In 2014 the Nobel prize for physics was awarded to a research team who invented a new kind of LED diode. Light emitting diodes (LEDs) have been around for ages, so what makes this new variant so special? This article discusses how LEDs work and what makes this light-emitting technology so special.
Light Emitting Diodes – or LEDS for short – are a variety of semiconductor that generates light when current passes through it. First invented in 1962, LEDs have always been good as indication lights but for a long time their low levels or brightness kept them away from from traditional lighting applications. Due to recent developments in the technology they have started replacing incandescent light bulbs in everyday use. This article will introduce the LED, discuss the technology, applications, and why a certain LED was worthy of the 2014 Nobel prize in physics.
Light has always been a necessity for life as we know it. For most creatures, early humans included, light came from the sun. The discovery of fire, an invention of mythological proportions brought about humanity’s first artificial and controllable light source, illuminating caves, little houses on the prairie, and big Victorian manors. The next milestone didn’t come for thousands of years at the invention of the incandescent light bulb. The incandescent bulb would reign supreme for about a century until fluorescent bulbs were invented, and then, finally, the led bulb.
LED light bulbs have been gaining immense popularity in the past few years because they can be just as bright as incandescents, but with higher efficiency and a longer expected lifetime.
But there is a half-century unaccounted for during which LEDs existed but LED light bulbs did not. In the first few years LEDs could do no more than generate tiny, barely visible amounts of light; the idea of illuminating any real amount of space was completely infeasible. In general, LED bulbs lacked price efficiency and energy efficiency. The metric for measuring the efficiency of a light bulb is in lm/W, or lumens per watt. A lumen is a measure of light brightness over an area, and a watt is a measure of energy consumption. In layman’s terms, light efficiency is (brightness / energy).
Before we begin talking about light emitting diodes it would do us well to discuss the physics behind light itself. Light is a kind of electromagnetic wave. The everyday light that we think of as “Light” is actually only a narrow band on the electromagnetic spectrum. Other kinds of electromagnetic waves are radio waves, microwaves, x-rays and gamma rays. All of these are forms of light, but they are outside the visible spectrum so we do not see them as traditional light. The wavelength of the light will determine what kind of wave it is, and with in the visible light spectrum it will also determine the color of the light: As seen in Figure 2, Light with a wavelength of approximately 700nm will appear red, and light with a wavelength of approximately 400nm will appear blue or purple.
This means that if we have light of a specific wavelength, we will see it only in that color. Everyday objects have color because they reflect certain wavelengths of light more than others. A green apple reflects green light, a red fire hydrant reflects red light. If one shines red light on a green apple, the light is absorbed instead of reflected. White light is a composition of every color of light. When one shines white light on a green apple the green is reflected but the other colors are all absorbed. Therefore, the light coming off of the apple is green and the apple appears green to the human eye.
Light Emission and the Bohr Model
There is no specific wavelength of visible light with the color white. This is because it is possible to generate different colors of light by combining multiple different wavelengths of light. White light is actually the equal combination of every wavelength of visible light. A typical light bulb with a whitish-yellow light happens when the light emits most colors of light, but emits more light with a yellow wavelength than others. The typical emission spectrum of a household light bulb can be seen below in Table 1. Our sun is also strong around the yellow spectrum, and other stars that appear red or blue have their corresponding color intensities.
LEDs, on the other hand, only emit a handful of wavelengths of light. This is because the materials that LEDs are made of, unlike stars or incandescents, are only able to emit a certain few wavelengths when electrically excited. As Table 1 shows, different LEDs have different emission spectra: each with a very thin emission spectrum. LEDs only emit one color of light not because they have colored plastic over white light, but because they only emit light at a single wavelength.
The Bohr model of the atom explains how atoms emit various lights. A typical atom has some amount of both electrons and protons: typically these counts are are equal and they define the atom’s behavior. Typically, the electrons come in shells: each with a different associated energy.
When the atom receives energy, (electrical, thermal, mechanical, etc) electrons can move out to higher energy shells. Then, when the electrons move back down to lower energy shells they release a specific wavelength of light. This is an oversimplification of the behavior, but the important takeaway is that there are only a few specific frequencies of light that can be emitted by atoms.
The typical operation of an incandescent light bulb can be seen in Figure 3. When electricity passes through a coil of a certain material, the electrons crash into the atoms of the material, exciting the atoms. Then, as the atoms lose energy, they emit light. Incandescent lights force electrons to higher energy levels, then when the electrons fall back down the light is emitted. However, incandescent lights brute force this process: there is no control over how the energy is absorbed and released. This means that the color of the light coming out of an incandescent bulb is essentially random, and the composition of all those random colors is the white light we see from those bulbs.
LEDs generate light differently than incandescents. While incandescent filaments randomly and haphazardly throw out light of many wavelengths, LEDs go about the process in a much more regulated and refined way. Through a process known as recombination, electrons flowing in one direction combine with holes – a current that flows via the absence of electrons – flowing in the other direction. When these two currents meet, the electrons and the holes recombine, restoring the electrical neutrality of the conductor. The electrons will be in a higher energy level than the holes though, so as the electron falls down it emits exactly the right wavelength of light desired.
Different LED colors are generated by controlling how far the electron falls into the hole it combines with. Different wavelengths of light are produced by different voltage potentials between the two currents. In general, the color and intensity of the light produced depends on the chemical makeup of the semiconductor. Infrared emitting LEDs, which emit a wavelength slightly longer than visible red light, were the first LEDs ever invented back in 1962. (Hall et al.) Infrared LEDs were first made of Gallium Arsenide (GaAs. By adding phosphorous to make GaP or Gallium Phosphide diodes, all sorts of other colors such as red green and yellow. A lot of work has gone into discovering new semiconductors that emit colors brighter or more efficiently, but for a very long time researchers struggled to make blue LEDs, let alone affordable blue light.
Blue LEDs, White LEDs and Spectrum Adjustment
For a long time, scientists and researchers chased the holy grail that was the fabrication of blue or short wavelength LEDs. Green and red LEDs had already existed, but to build a white LED light blue would also be needed. The problem was that while blue LEDs could be made out of GaN, or Gallium Nitride, growing a pure crystalline lattice of the material proved exceptionally difficult. It wasn’t until 1989 that the first blue led appeared in research labs thanks to completely new fabrication techniques that introduced new levels of precision and control to the process. By 1992, the addition of Aluminum Gallium Nitride (AlGaN) and layers of Indium Gallium Nitride (GaInN) improved light efficiency tenfold. Since then, efficiency has improved tenfold again. For their efforts in this development, Isamu Akasaki, Hiroshi Amano and Shuji Nakamura were awarded the 2014 Nobel Prize in physics.
Alone, a blue LED does not mean much. These days, pure blue leds are mostly used for power buttons or other decals and indicators. The invention of the blue LED was not important because it is blue, it is important because it enabled white colored LED light. When a red LED. A green LED and a blue LED are put in close proximity to each other and the light is diffused, the resulting color is a white led. And if only one or two of the LEDs are on, any color of light can be created. The other method of creating white light is known as spectrum adjustment.
Spectrum adjustment happens when light is absorbed and then re-emitted again. By doing so, the color and appearance of the light can be altered. There is a caveat, however, that the light can only be shifted to larger wavelengths. If a material were able to absorb a long wavelength of light and emit the same amount of a shorter wavelength, this would violate the conservation of energy. This is why it was not possible to generate blue light from other diodes. However, the reverse process does in fact work: if a blue diode is passed thorough a yellow phosphor, the blue and yellow combine into a white light well suited for everyday tasks.
LEDs in Everyday Applications
Before they were available as household lights, LEDs served as indicators in devices and continue to to this day. LEDs as indicators are an essential and powerful learning tool for beginner electronics: They provide immediate feedback as to if a circuit is properly working. In fact, one ofthe first programs that anyone learning the Arduino platform will write is called “blink” and all that it does is blink an LED.
Beyond homes and headlights, LED lamps have started moving into city planning offices. Due to their efficiency and long lifetimes, LED street lamps have begun phasing into many cities across the globe, including Somerville, Arlington, and many other towns in Massachusetts. LEDs as lights is where the big breakthroughs have been in the past few years, so the primary question now is how many devices can we integrate LEDs into and how quickly can we integrate these bew lighting forms into society’s infrastructure.
Now that LEDs have surpassed traditional lighting methods in terms of lifetime and efficiency, they have opened the floodgates of efficiency to other light-using technologies. LCD televisions, for example, once required large fluorescent lights that would be filtered through an LDC display to produce an image on screen. By using an array of white LEDs instead, not only is power usage drastically lowered, but it’s even possible to make higher contrast screens, by actually dimming the light in certain areas instead of just filtering it out.
On the subject of screens, some screens are made entirely of OLEDs – or organic LEDs. Rather than standard LEDs which typically have a small light-emitting area, OLEDs are made of many planar sheets that form a full surface capable of light emission. OLEDs reduce the thickness of devices and allow screens that are made of just LEDs – no LCD filter required. While the technologies and chemical compositions are different than normal LEDs, they are still relevant as one of the next big frontiers of LEDs.
To quote the Nobel Prize article on the invention: “Incandescent light bulbs had lit the 20th century; the 21st century will be lit by LED lamps.“ Compared to Incandescents lights, LEDs are better in almost every way. They have a smaller energy footprint, they have a longer lifespan and they can be put into a smaller package. Lights account for 19% of the energy that the whole world uses, and incandescent lights are only 5% effective. If all of that energy went into incandescent lights, that would mean over 18% of the world’s energy is immediately lost as heat. That’s a huge amount. LEDs are more expensive to create and manufacture but they pay for themselves in energy savings in no time at all.
New technology often struggles with mass adaption. However, thanks to the short lifespan of incandescent bulbs, the process of phasing them out is much easier than it could be. As energy usage rises worldwide, the integration of this technology could be key for butting back. Blue LEDs are not only for lighting, they also appear in the new LED and OLED based screens for televisions and phones. Upon closer inspection of many devices, LEDs much more prevalent and much more significant to everyday technology than one might think.
- Akasaki, I. (2007). Key inventions in the history of nitride-based blue LED and LD 300(1). DOI: 10.1016/j.jcrysgro.2006.10.259
- Aspense, D.E., Studna, A.A. (1983). Dielectric functions and optical parameters of Si, Ge, GaP, GaAs, GaSb, InP, InAs, and InSb from 1.5 to 6.0 eV. Phys. Rev. B 27(2). DOI: 10.1103/PhysRevB.27.985
- Bergstrom, L., Delsing, P., L’Huillier, A., Inganas, O., Rose, J., Blue LEDs – Filling the world with new light. Retrieved from the Royal Swedish Academy of Sciences
- Hall, R.N., Fenner, G.E., Kingsley, J.D., Soltys, T.J., Carlson, R.O. ( ). Coherent Light Emission from GaAs Junctions. Phys. Rev. Letters 9(9). DOI: 10.1103/PhysRevLett.9.366
- Kalinowsk, J., Di Marco, P., Fattori, V., Giuletti, L., Cocchi, M., (1998). Voltage-induced evolution of emission spectra in organic light-emitting diodes. Journal of Applied
Physics, 4242-4242. DOI: 10.1063/1.367181
- Kamtekarm, K., Monkman, A., Bryce, M., (2009) Recent Advances in White Organic Light-Emitting Materials and Devices (WOLEDs). Adv. Mater. 2010, 22, 572–582. DOI: 10.1002/adma.200902148
- Park, J., Lee J.H., Raju, S.R., Moon, B.K., Jeong, J.H., Choi, B.C., Kim, J.H. (2014). Ceramics International, 40(4). DOI: 10.1016/j.ceramint.2013.11.007
- Sato, T., Imai, M.(2002). Characteristics of Nitrogen-Doped GaAsP Light-Emitting Diodes. Jpn. J. Appl. Phys. DOI: 10.1143/JJAP.41.5995
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Thermal hand gesture recognition
Human-Machine interfaces (HMI) based on hand gesture recognition allow natural, intuitive, and simple communication. Among the different existing technologies, the computer vision stands out for not being intrusive or invasive: the user has not to wear sensors or any additional hardware, providing a great interactivity experience.
In this project, a visual hand-gesture recognition system using very low resolution infrared imagery has been developed. This kind of images has a lot of competitive advantages over the images taken in the visible light spectrum, due to the better signal-interference ratio and independency of the illumination conditions. The main challenges are: the low resolution of the thermal images (80x60) and the reduced hand size inside the image (it only occupies about a 10% of the image). The developed system is based on deep learning algorithms, using Convolutional Neural Networks with a ResNet architecture.


|Year : 2016 | Volume
| Issue : 4 | Page : 145-152
The use of adaptive optics for retinal imaging with microscopic resolution
Mortada A Abozaid
Department of Ophthalmology, Faculty of Medicine, Sohag University, Sohag, Egypt
|Date of Submission||07-Dec-2016|
|Date of Acceptance||27-Feb-2017|
|Date of Web Publication||19-Apr-2017|
Mortada A Abozaid
Department of Ophthalmology, Faculty of Medicine, Sohag University, Sohag
Source of Support: None, Conflict of Interest: None
Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effects of optical aberrations. Adding AO to retinal imaging tools allows noninvasive direct visualization of the photoreceptor cells, capillaries, and nerve fiber bundles by correcting the eye’s monochromatic aberrations. AO can provide new information on the early pathological changes of the retinal microstructures in various retinal diseases, can also monitor response to novel treatments at the cellular level, and can help better select candidates for such treatments. This review discusses the basics, clinical applications, and challenges of AO retinal imaging.
Keywords: adaptive optics, high resolution, noninvasive, retinal imaging
|How to cite this article:|
Abozaid MA. The use of adaptive optics for retinal imaging with microscopic resolution. J Egypt Ophthalmol Soc 2016;109:145-52
| Introduction|| |
The benefits of adaptive optics (AO) were known long before the technology was available for retinal imaging . The original problem was of image degradation arising in ground-based telescopes owing to turbulence in the earth’s atmosphere. The US army appreciated the benefits of this and funded programs during the 1970s and 1980s to develop the technology for imaging foreign satellites with ground-based telescopes . Much of the military’s information was declassified in 1992 after dissolution of the Soviet Union, a move that accelerated progress for all nonmilitary applications of AO. In 1996, AO were successfully applied to high-resolution imaging in the human eye .
AO imaging can provide clinicians with high-resolution views of the retina which allow better understanding of the early pathological changes of the retinal microstructures in various retinal diseases in addition to tracking of disease progression and following treatment response with greater sensitivity and over a much shorter time than other outcome measures such as visual acuity and visual field sensitivity.
Adaptive optics components
AO is a technology used to improve the performance of optical systems by reducing the effects of optical aberrations. By correcting the eye’s monochromatic aberrations, AO provides nearly diffraction-limited high-resolution imaging of the retina. AO by itself does not provide a retinal image, rather an AO subsystem must be incorporated into an existing imaging device, for example, flood illumination fundus camera, confocal scanning laser ophthalmoscope, or spectral-domain optical coherence tomography (OCT), with each modality having its own advantages and limitations.
AO retinal imaging system has three main components: a wavefront sensor, a corrective (adaptive) element, and a control system ([Figure 1]). The wavefront sensor (mostly a Hartman–Shack design) is used to measure the aberrations of the eye. The corrective element is used to compensate for these aberrations, most commonly by using a deformable mirror, which relies on a series of piezoelectric actuators to deflect the mirror surface. The third main component, a software system, controls the interaction between the wavefront sensor and the corrective element .
|Figure 1 Schematic diagram of an adaptive optics retinal imaging system .|
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Retinal structures visible with adaptive optics
Cone photoreceptors serve as relatively easy targets for AO imaging because of the unique waveguiding properties of their outer segments. In fact, in eyes of good optical quality, it is possible to resolve cone photoreceptors without the use of AO ,. The first images of the cone mosaic were published in 1996, using a conventional fundus camera equipped with AO ,. One of the first observations was then made in patients with color vision deficit, where AO found a reduction of one type of cones rather than total absence of particular cone type as previously thought . Another significant observation was that both cones and rods vary in their intensity over time ,. AO imaging efforts usually focus on analyzing the cone density and spacing ,,,,,,,,. In addition, assessment of mosaic geometry and regularity may detect more subtle changes of the photoreceptors .
Recently, Scoles et al.  developed a new ‘split-detector’ adaptive optics scanning laser ophthalmoscope (AOSLO) method to directly visualize the cone inner segment structures in a manner independent of the waveguide properties of the photoreceptor (which conventional confocal AOSLO imaging relies on) ([Figure 2]).
|Figure 2 Confocal (a) and split-detector (b) adaptive optics scanning laser ophthalmoscope images of the photorecetotors of the left eye of a normal patient (JC_10329), taken at ∼7° eccentricity (scale bar 20 µm, crop 150×150 µm).|
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The difficulties in rod imaging are attributed to their small diameter (∼2 µm)  and poor waveguiding properties compared with cones ,,. Dubra et al.  were the first to image the smallest photoreceptors, the cones at the foveal center and the rods, using AOSLO. Rods are of great importance as they are the most abundant of photoreceptors and are often the first cells to get disrupted in many types of retinal disease.
Apart from the photoreceptors, the retinal pigment epithelium (RPE) cells can be seen using reflectance-based AO imaging . Also, with AO, we can observe individual leukocytes moving through small retinal blood vessels, which allows imaging of the parafoveal capillary network and measurement of leukocyte velocity without contrast dyes . In addition, AO can be used to identify individual nerve fiber bundles and provide high-resolution images of both the retinal nerve fiber layer (RNFL) and the optic nerve head ,,.
Clinical retinal imaging with adaptive optics
Retinal dystrophies represent a heterogeneous group of retinal degenerations which all produce progressive death of the photoreceptors. The first published application of AO to image human retinal pathology was in 2000, where images, with microscopic resolution comparable with that of histology, from a patient with cone-rod dystrophy were presented and revealed a reduction in cone density .
Patients with RP and cone-rod dystrophy show different patterns of cone loss in AO images; primary cone degenerations cause increased cone spacing centrally, whereas cone-rod degeneration causes cone cell death adjacent to scotomas beginning around 10° eccentric to fixation, the retinal region with the highest density of rods  ([Figure 3]).
|Figure 3 Confocal (a) and split-detector (b) adaptive optics scanning laser ophthalmoscope images of the right eye of a patient with retinitis pigmentosa (KS_10070), taken at ∼7° eccentricity (scale bar 20 µm, crop 150×150 µm) .|
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Because the rate of disease progression is typically slow in inherited retinal degenerations, it is estimated that patients with RP, for example, must be monitored for 7–10 years before standard clinical measures of visual function, such as visual acuity and visual field sensitivity, to show significant evidence of disease progression ,.
Talcott et al.  monitored the cone mosaic using AOSLO in three patients with retinitis pigmentosa undergoing an experimental treatment with sustained-release of ciliary neurotrophic factor over 24 months and revealed a relative preservation of cone structure despite an absence of significant functional improvement as shown by significant differences in cone spacing between the treated eye and the fellow sham treated eye. This study suggests that AO-based imaging tools could provide sensitive anatomical outcome measures for clinical trials, providing more immediate feedback as to whether the therapeutic intervention has positively affected retinal structure or not.
In addition, assessment of the relative integrity of the photoreceptor mosaic may be useful for identifying individuals who may be good candidates for experimental therapies, such as gene therapy, and may permit specific areas of retained photoreceptor structure to be targeted for treatment .
AO imaging in patients and carriers with choroideremia demonstrated abnormalities of cone morphology and spacing, suggesting simultaneous RPE and photoreceptor cell degeneration. Such findings provide insight into the effect of choroideremia mutations on macular retinal structure, with implications for the development of future treatments .
AOSLO images of patients with X-linked retinoschisis revealed increased cone spacing and abnormal packing in the macula with near-normal cone coverage and function outside the central foveal schisis cavities. The limitation of degeneration of cone photoreceptors to regions near the anatomic fovea affected by large schisis cavities makes therapies for X-linked retinoschisis to be more likely to succeed than therapies for retinal degenerations that cause photoreceptor degeneration diffusely and directly .
In both dog and mouse models of achromatopsia, it was shown that cone function could be restored using a gene therapy approach ,,,. Translation of this specific approach to human trials requires that some cone cells remain intact. AO imaging of patients with achromatopsia revealed a substantial number of foveal and parafoveal cone photoreceptors with apparently intact inner segments .
A major obstacle that faces the use of AO in clinical trials is the need for assessing the reliability and repeatability of cone density measurements in these patients before subjecting them to novel treatments  ([Figure 4]).
|Figure 4 Confocal (a, b) and split-detector (c, d) adaptive optics scanning laser ophthalmoscope images of two patients with achromatopsia; JC_10069 (a, c) and MM_0005 (b, d) .|
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Albinism is an inherited disorder of melanin biosynthesis and is associated with a disruption in normal retinal development, with foveal hypoplasia (absence of a foveal pit) being the predominant ocular phenotype.
Marmor et al.  used AO to image the parafoveal cones in four patients with unspecified foveal hypoplasia. They observed ‘normal’ cone specialization (cone packing and outer nuclear layer thickening); however, no quantitative analysis was provided.
McAllister et al.  examined six individuals with albinism and found variation in the degree of foveal hypoplasia and corresponding variation in foveal cone specialization (measuring cone packing gradients and foveal outer segment lengthening).
Wilk et al.  showed a wide range of foveal morphology and foveal cone specialization in patients with albinism and concluded that although a foveal pit is not required for foveal cone specialization, it may facilitate further cone packing.
Glaucoma is the leading cause of irreversible, preventable blindness worldwide. Primary open-angle glaucoma is a chronic optic neuropathy characterized by progressive loss of retinal ganglion cells, usually associated with ocular hypertension . AO imaging tools can visualize both the RNFL and lamina cribrosa with high resolution ,,,.
Akagi et al.  noted that the laminar pore area was affected by axial length and intraocular pressure. Nadler et al.  showed regional differences in microarchitecture in healthy lamina cribrosa as obtained in-vivo using three-dimensional AO-OCT scans. Such structural variation should prove useful in further evaluation of the role of lamina cribrosa microarchitecture in glaucoma .
Chen et al.  showed that the details near the borders between OCT measured RNFL thickness within and outside normal limits can be visualized with AOSLO. Details in these regions are difficult or impossible to see using OCT scans or to measure using perimetry. They concluded that AOSLO may have a role in clinical trials needing a measure of progression . Moreover, Hood et al.  showed that relatively similar 10–2 defects with similar OCT RNFL thickness profiles can have very different degrees of RNF bundle damage as seen on OCT and AOSLO.
AO may help recognize early glaucomatous damages and identify patients who may progress rapidly and also may benefit from more intensive observation and management.
In addition, AO imaging can have an important role in the evaluation of benefits of the neuroprotective agents.
Diabetic retinopathy (DR) is a microangiopathy resulting from blood rheological abnormalities because of chronic hyperglycemia ,,.
Rather than purely a vascular disease, it is now considered a neurovascular disorder. The neurodegeneration in DR consists of apoptosis affecting the photoreceptors, bipolar cells, and ganglion cells ,. AO imaging can provide noninvasive images of the retinal microvascular damages in patients with DM without the need of contrast agents, by detecting microaneurysms, increased foveal avascular zone (FAZ) size, and dropout of capillaries at the edge of the FAZ ,,. Tam et al.  evaluated the parafoveal capillary network in 15 patients with type 2 diabetes and no retinopathy. They showed a higher tortuosity of the arteriovenous channels in eyes of patients with diabetes and no DR than in healthy controls . In a follow-up study, assessment of the capillaries near the FAZ showed microaneurysm formation and disappearance as well as the de novo formation of tiny capillary bends similar in appearance to intraretinal microvascular abnormalities . Sun et al.  reported disruption of the cone photoreceptor mosaic in patients with type 1 diabetes using AOSLO.
Han et al.  used AO to visualize photoreceptors after macular laser photocoagulation with pattern laser and noted no evidence of reduced photoreceptor density around the laser lesions, no apparent size reduction of the lesions relative to the initial application diameters, and thus, no direct evidence of photoreceptor migration or healing was found.
Burns et al.  used large aperture AOSLO imaging to visualize directly numerous capillary abnormalities in patients with mild and moderate nonproliferative diabetic retinopathy, and suggested that these changes could contribute to the variability in response to treatment in diabetic patients and could be useful for improving clinical classification of diabetic patients, better understanding of the mechanisms of DR, and development of more effective therapies through better patient monitoring of pharmacological intervention.
Age-related macular degeneration
Age-related macular degeneration (AMD) is a multifactorial disease involving ocular, systemic, and genetic risk factors that can cause severe vision loss owing to either tissue loss in the macula or development of subfoveal choroidal neovascular membranes. AMD is the leading cause of blindness in the elderly across the developed world .
Although the changes in late stages of AMD are known, it is important to detect very early stages of the disease to predict its course ,. AO imaging can monitor drusen over time and assess their effect on the overlying photoreceptor mosaic. Preservation of cones over the drusen was observed in a patient with early-onset large colloid drusen , as well as in a patient with basal laminar drusen . Boretsky et al.  identified several small drusen deposits that were not observed with wide-field fundus imaging or spectral-domain OCT in early AMD. They also investigated large coalescent drusen and areas of geographic atrophy in advanced stages of dry AMD and showed a significant decrease in photoreceptor density. Nakashima et al.  showed disruptions of the photoreceptor mosaic outside the clinically visible geographic atrophy lesions and tracked the progression of the geographic atrophy (GA) lesions over time.
Soudry et al.  measured cone spacing at the margin of GA and over drusen in eyes with non-neovascular AMD and found that cone spacing was normal at baseline and remained normal over time. However, these regions showed focal areas of abnormal morphologic features and decreased cone reflectivity suggesting that changes in cone spacing may not represent a primary structural change in AMD progression .
Challenges to adaptive optics imaging
Although established as a powerful research tool, AO still lacks a widespread clinical use. This is owing to lack of clinical access and availability because of the high cost, large size of the imaging machine, and the time and expertise required for acquisition registration, montaging, and quantitative analysis of the images obtained by AO. However, numerous compact designs and commercial clinical prototypes have been developed ,,,,, and some companies having developed AO machines (Boston Micromachines Corporation).
Patient factors, such as unstable fixation, small pupil size, and media opacities, can add to the difficulties with image stabilization and light scatter, resulting in image blur. Another challenge facing AO technology is the need for characterizing the properties of normal photoreceptor mosaic, with establishment of normative databases for the cone density and spacing and mosaic geometry. Such databases are critical to detect deviation from normality. Similar databases are also needed for quantifying blood flow, determining capillary density, measuring RNFL bundles, measuring lamina cribrosa pore size, and assessing intrinsic RPE autofluorescence. Many studies to assess the reliability and repeatability of methods used to quantify these variables are also needed.
In addition, there is a lack of systematic studies that examine the same diseases with different AO imaging modalities (flood, SLO, and OCT) to detect the relative information provided by each modality and hence the advantages and disadvantages of each, which would certainly vary on a disease-by-disease basis.
| Conclusion|| |
Although there are many challenges to the clinical application of AO retinal imaging, the current opportunities are many. The early diagnosis of retinal diseases and the monitoring of treatment efficacy at a cellular level provides promising clinical applications of AO technology. The use of AO imaging in clinical trials could potentially enable targeting of treatments to specific patients or specific retinal areas and allow for more sensitive evaluation of treatment effects.
The author thanks Joseph Carroll, PhD, Lynn Sun, MD, PhD, and Christopher S. Langlo, MD, Eye Institute, Medical College of Wisconsin, Milwaukee, USA, for providing the figures.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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Chui TY, Song H, Burns SA. Adaptive-optics imaging of human cone photoreceptor distribution. J Opt Soc Am A Opt Image Sci Vis 2008; 25:3021–3029.
Song H, Chui TYP, Zhong Z, Elsner AE, Burns SA. Variation of cone photoreceptor packing density with retinal eccentricity and age. Invest Ophthalmol Vis Sci 2011; 52:7376–7384.
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Scoles D, Sulai YN, Langlo CS, Fishman GA, Curcio CA, Carroll J, Dubra A. In vivo imaging of human cone photoreceptor inner segments. Invest Ophthamol Vis Sci 2014; 55:4244–4251.
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Dubra A, Sulai Y, Norris JL, Cooper RF, Dubis AM, Williams DR, Carroll J. Noninvasive imaging of the human rod photoreceptor mosaic using a confocal adaptive optics scanning ophthalmoscope. Biomed Opt Express 2011; 2:1864–1876.
Roorda A, Zhang Y, Duncan JL. High-resolution in vivo imaging of the RPE mosaic in eyes with retinal disease. Invest Ophthalmol Vis Sci 2007; 48:2297–2303.
Roorda A, Romero-Borja F, Donnelly W 3rd, Queener H, Hebert T, Campbell M. Adaptive optics scanning laser ophthalmoscopy. Opt Express 2002; 10:405–412.
Takayama K, Ooto S, Hangai M, Arakawa N, Oshima S, Shibata N et al.
High-Resolution imaging of the retinal nerve fiber layer in normal eyes using adaptive optics scanning laser ophthalmoscopy. PLoS One 2012; 7:e33158.
Huang G, Qi X, Chui TY, Zhong Z, Burns SA. A clinical planning module for adaptive optics SLO imaging. Optom Vis Sci 2012; 89:593–601.
Kocaoglu OP, Cense B, Jonnal RS, Wang Q, Lee S, Gao W, Miller DT. Imaging retinal nerve fiber bundles using optical coherence tomography with adaptive optics. Vis Res 2011; 51:1835–1844.
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Sun LW, Johnson RD, Langlo C, Cooper RF, Razeen M, Russillo MC et al.
Assessing photoreceptor structure in retinitis pigmentosa and usher syndrome. Invest Ophthalmol Vis Sci 2016; 57:2428–2442.
Grover S, Fishman GA, Anderson RJ, Alexander KR, Derlacki DJ. Rate of visual field loss in retinitis pigmentosa. Ophthalmology 1997; 104:460–465.
Fishman GA, Bozbeyoglu S, Massof RW, Kimberling W. Natural course of visual field loss in patients with Type 2 Usher syndrome. Retina 2007; 27:601–608.
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Longitudinal study of cone photoreceptors during retinal degeneration and in response to ciliary neurotrophic factor treatment. Invest Ophthalmol Vis Sci 2011; 52:2219–2226.
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Identifying photoreceptors in blind eyes caused by RPE65 mutations: Prerequisite for human gene therapy success. Proc Natl Acad Sci USA 2005; 102:6177–6182.
Syed R, Sundquist SM, Ratnam K, Zayit-Soudry S, Zhang Y, Crawford JB et al.
High-resolution images of retinal structure in patients with choroideremia. Invest Ophthalmol Vis Sci 2013; 54:950–961.
Duncan JL, Ratnam K, Birch DG, Sundquist SM, Lucero AS, Zhang Y et al.
Abnormal cone structure in foveal schisis cavities in X-linked retinoschisis from mutations in exon 6 of the RS1 gene. Invest Ophthalmol Vis Sci 2011; 52:9614–9623.
Alexander JJ, Umino Y, Everhart D, Chang B, Min SH, Li Q et al.
Restoration of cone vision in a mouse model of achromatopsia. Nat Med 2007; 13:685–687.
Komaromy AM, Alexander JJ, Chiodo VA, Hauswirth WW, Acland GM, Aguirre GD. Cone directed gene therapy with rAAV leads to restoration of cone function in a canine model of achromatopsia. Invest Ophth Vis Sci 2007; 48:4614.
Komaromy A, Alexander JJ, Rowlan JS, Garcia MM, Chiodo VA, Kaya A et al.
Gene therapy rescues cone function in congenital achromatopsia. Hum Mol Genet 2010; 19:2581–2593.
Carvalho LS, Xu J, Pearson R, Smith AJ, Bainbridge JW, Morris LM et al.
Long-term and age-dependent restoration of visual function in a mouse model of CNGB3-associated achromatopsia following gene therapy. Hum Mol Genet 2011; 20:3161–3175.
Abozaid MA, Langlo CS, Dubis AM, Michaelides M, Tarima S, Carroll J. Reliability and repeatability of cone density measurements in patients with congenital achromatopsia. Adv Exp Med Biol 2016; 854:277–283.
Marmor MF, Choi SS, Zawadzki RJ, Werner JS. Visual insignificance of the foveal pit: reassessment of foveal hypoplasia as fovea plana. Arch Ophthalmol 2008; 126:907–913.
McAllister JT, Dubis AM, Tait DM, Ostler S, Rha J, Stepien KE et al.
Arrested development: high-resolution imaging of foveal morphology in albinism. Vision Res 2010; 50:810–817.
Wilk MA, McAllister JT, Cooper RF, Dubis AM, Patitucci TN, Summerfelt P et al.
Relationship Between Foveal Cone Specialization and Pit Morphology in Albinism. Invest Ophthalmol Vis Sci 2014; 55:4186–4198.
Quigley HA. Glaucoma. Lancet 2011; 377:1367–1377.
Scoles D, Gray DC, Hunter JJ, Wolfe R, Gee BP, Geng Y et al.
In-vivo imaging of retinal nerve fiber layer vasculature: imaging − histology comparison. BMC Ophthalmol 2009; 9:9.
Ivers KM, Li C, Patel N, Sredar N, Luo X, Quenner H et al.
Reproducibility of measuring lamina cribrosa pore geometry in human and nonhuman primates with in vivo adaptive optics imaging. Invest Ophth Vis Sci 2011; 52:5473–5480.
Akagi T, Hangai M, Takayama K, Nonaka A, Ooto S, Yoshimura N. In vivo imaging of lamina cribrosa pores by adaptive optics scanning laser ophthalmoscopy. Invest Ophthalmol Vis Sci 2012; 53:4111–4119.
Nadler Z, Wang B, Schuman JS, Ferguson RD, Patel A, Hammer DX et al.
In vivo three-dimensional characterization of the healthy human lamina cribrosa with adaptive optics spectral-domain optical coherence tomography. Invest Ophthalmol Vis Sci 2014; 55:6459–6466.
Chen MF, Chui TYP, Alhadeff P, Rosen RB, Ritch R, Dubra A et al.
Adaptive optics imaging of healthy and abnormal regions of retinal nerve fiber bundles of patients with glaucoma. Invest Ophthalmol Vis Sci 2015; 56:674–681.
Hood DC, Chen MF, Lee D, Epstein B, Alhadeff P, Rosen RB et al.
Confocal adaptive optics imaging of peripapillary nerve fiber bundles: implications for glaucomatous damage seen on circumpapillary OCT scans. Trans Vis Sci Tech 2015; 4:12.
Cunha-Vaz JG. Pathophysiology of diabetic retinopathy. Br J Ophthalmol 1978; 62:351–355.
Kern TS, Engerman RL. Vascular lesions in diabetes are distributed non-uniformly within the retina. Exp Eye Res 1995; 60:545–549.
Moore J, Bagley S, Ireland G, McLeod D, Boulton ME. Three dimensional analysis of microaneurysms in the human diabetic retina. J Anat 1999; 194:89–110.
Lieth E, Gardner TW, Barber AJ, Antonetti DA. Retinal neurodegeneration: early pathology in diabetes. Clin Exp Ophthalmol 2000; 28:3–8.
Barber AJ. A new view of diabetic retinopathy: a neurodegenerative disease of the eye. Prog Neuropsychopharmacol Biol Psychiatry 2003; 27:283–290.
Tam J, Dhamdhere KP, Tiruveedhula P, Manzanera S, Barez S, Bearse MA Jr et al.
Disruption of the retinal parafoveal capillary newtork in type 2 diabetes before the onset of diabetic retinopathy. Invest Ophth Vis Sci 2011; 52:9257–9266.
Tam J, Dhamdhere KP, Tiruveedhula P, Lujan BJ, Johnson RN, Bearse MA Jr et al.
Subclinical capillary changes in non-proliferative diabetic retinopathy. Optom Vis Sci 2012; 89:E692–E703.
Lombardo M, Parravano M, Serrao S, Ducoli P, Stirpe M, Lombardo G. Analysis of retinal capillaries in patients with type 1 diabetes and non proliferative diabetic retinopathy using adaptive optics imaging. Retina 2013; 33:1630–1639.
Han DP, Croskrey JA, Dubis AM, Schroeder B, Rha J, Carroll J. Adaptive optics and spectral domain optical coherence tomography of human photoreceptor structure after short-duration [corrected] pascal macular grid and panretinal laser photocoagulation. Arch Ophthalmol 2012; 130:518–521.
Burns SA, Elsner AE, Chui TY, VanNasdale DA Jr, Clark CA, Gast TJ et al.
In vivo adaptive optics microvascular imaging in diabetic patients without clinically severe diabetic retinopathy. Biomed Opt Express 2014; 5:961–974.
Bressler NM. Age-related macular degeneration is the leading cause of blindness. JAMA 2004; 291:1900–1901.
Freeman SR, Kozak I, Cheng L, Bartsch DU, Mojana F, Nigam N et al.
Optical coherence tomography raster scanning and manual segmentation in determining drusen volume in age-related macular degeneration. Retina 2010; 30:431–435.
Greenberg JP, Duncker T, Woods RL, Smith RT, Sparrow JR, Delori FC. Quantitative fundus autofluorescence in healthy eyes. Invest Ophthalmol Vis Sci 2013; 54:5684–5693.
Querques G, Massamba N, Guigui B, Lea Q, Lamory B, Soubrane G et al.
In vivo evaluation of photoreceptor mosaic in early onset large colloid drusen using adaptive optics. Acta Ophthalmol (Copenh) 2012; 90:e327–e328.
Godara P, Siebe C, Rha J, Michaelides M, Carroll J. Assessing the photoreceptor mosaic over drusen using adaptive optics and SD-OCT. Ophthalmic Surg Lasers Imaging 2010; 41:S104–S108.
Boretsky A, Khan F, Burnett G, Hammer DX, Ferguson RD, van Kuijk F et al.
In vivo imaging of photoreceptor disruption associated with age-related macular degeneration: a pilot study. Lasers Surg Med 2012; 44:603–610.
Nakashima K, Ullern M, Benchaboune M, Sahel JA, Paques M. Adaptive optics imaging of geographic atrophy. Invest Ophth Vis Sci 2012; 53:2052.
Soudry SZ, Duncan JL, Syed R, Menghini M, Roorda AJ. Cone structure imaged with adaptive optics scanning laser ophthalmoscopy in eyes with nonneovascular age-related macular degeneration. Invest Ophthalmol Vis Sci 2013; 54:7498–7509.
Zhang Y, Poonja S, Roorda A. MEMS-based adaptive optics scanning laser ophthalmoscopy. Opt Lett 2006; 31:1268–1270.
Mujat M, Ferguson RD, Patel AH, Iftimia N, Lue N, Hammer DX. High resolution multimodal clinical ophthalmic imaging system. Opt Express 2010; 18:11607–11621.
Bigelow CE, Iftimia NV, Ferguson RD, Ustun TE, Bloom B, Hammer DX. Compact multimodal adaptive-optics spectral-domain optical coherence tomography instrument for retinal imaging. J Opt Soc Am A Opt Image Sci Vis 2007; 24:1327–1336.
Burns SA, Tumbar R, Elsner AE, Ferguson D, Hammer DX. Large-field-of-view, modular, stabilized, adaptive-optics-based scanning laser ophthalmoscope. J Opt Soc Am A Opt Image Sci Vis 2007; 24:1313–1326.
Mujat M, Ferguson RD, Iftimia N, Hammer DX. Compact adaptive optics line scanning ophthalmoscope. Opt Express 2009; 17:10242–10258.
[Figure 1], [Figure 2], [Figure 3], [Figure 4]


This NEON Science video overviews what lidar or light detection and ranging is, how it works and what types of information it can provide. The video was produced by the National Ecological Observatory Network – a non-profit project devoted to open science and open data. Suggested citation for this video: National Ecological Observatory Network. November 6, 2014. How Does LiDAR Remote Sensing Work? Light Detection and Ranging [Video file]. Courtesy: Battelle.
Retrieved from https://youtu.be/EYbhNSUnIdU.
The systems that currently drive robot cars cost upward of US$100,000 per vehicle – not counting the cost of the car itself.
Lower Cost LiDar Makers.


Safety glasses have always been considered as an important equipment in any working industry or factory. Safety glasses not only protects our eyes from damage, but from the chemicals and dust particles too.
Modern range of safety glasses
Modern range of eye protection glasses helps in bringing a proper functionality, quality, design, and safety of the glass and eyes. This helps in maintaining a pace with the rapid increase of industrial advancements and constructions that is going on. And, this is the major expectation of the customers that their eyes are kept safe from any chemical or physical damage.
Market of glasses
You will get a wide range of models of safety glasses and safety eye goggles too in Singapore. There is a wide range of protective eyewear that will provide the ultimate safety for your eyes. The products of eyewear include anti scratch safety glasses, safety spectacles, anti-fog goggles, safety sunglasses, safety goggles, welding protection eyewear, and many more.
Before you buy the glasses, just make sure to differentiate between these glasses as they are highly classified on the basis of their use in different places such as welding protection eyewear in welding industries, and anti-scratch safety glasses in factories.


The possibility of using electric hydrogels as materials in lenses with variable focal length (“smart lenses”) has been investigated. The focus is on identifying and controlling parameters such as the density of the surface connection and the degree of neutralization that affects the properties of the required gel. These characteristics include optical transparency, structural strength and electrical reactivity. The transmission of an electrical signal to the gel is investigated by determining the ideal shape, location, and material for the electrodes used in Smart Lens applications. Types of materials are tested with mixed results, and suitable electrode materials are recommended. The structural and optical properties of the gels are evaluated through swelling and optical transmissivity measurements. However, there are some apparent anomalies that are attributed to limitations in existing knowledge about gel swelling processes.


Jan 05, 2021 · Lens Coating. Lens coating is an important feature of a spotting scope, especially for viewing images at high magnifications. The lens can be fully coated, multi-coated, or fully multi-coated. Each lens coating improves the light transmitting into the lens, but the quality depends on the coating chosen for the specific scope.
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Dec 21, 2020 · For such an affordable m4/3 lens, the Panasonic 25mm f/1.7 is offers a lot in the way of high quality build, despite being so lightweight. The metal mount provides durability for active use, and uses multi-coated lens elements that minimize ghosts and flare to further enhance its shooting performance.
A119S Dashcam F1.6 v1 Lens vs F1.8 v2 Lens Comparison Original 7G F1.6 v1 Lens = 98 degree HView, uncoated lens, metal base, blurry on left issue/soft focus New F1.8 v2 Lens = 101 degree HView, coated lens, plastic base, great focus. (discovered new F1.8 Lens has.
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Jun 01, 2017 · The 135mm f3.5 Takumar is a medium telephoto lens made by the Asahi Optical Company. One of the best telephoto vintage lenses, the 135mm Takumar has several versions, such as the Super, Super-Multi-Coated, and SMC. They all have the M42 mount and are basically the same in terms of optics and design.
Apr 26, 2017 · Lens coating is meant to improve color rendition, sharpness, contrast, and transmission. In general, a coated lens will give noticeably better results than an uncoated lens, and a multi-coated lens will give slightly better results than a single-coated lens. The difference will probably be most noticeable when using color reversal film (slide ...
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Barlow Lens 2X, Bysameyee 1.25 Inch Fully Multi-Coated Metal Barlow Lens with M42 Thread Camera Connect Interface for Telescope Eyepiece 4.4 out of 5 stars 169 £23.99 Jun 01, 2011 · I would go cheapie if I were to be in blowing grit, but otherwise, I just get the best multi-coated filter I can find for my largest lens, and step rings to attach it to smaller diameter lenses. I am frankly surprised that you could get any image at all through fifty filters, some of which are likely to be uncoated or single-coated.
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We deliver trendiest & fashionable colored contact lenses to alter the appearance of your natural eye color with broad color spectrum. Check out our latest items and Shop nowhere at the O-Lens online store for our latest cosmetic contact lenses. Enjoy it with our worldwide shipping service.H igh Quality: Blue AR Coating increasing optical clarity and colour fidelity. Multiple coated filter allows 99% transmittance compared to 90% transmittance of normal UV filters on the market. F ul ly Pro tection: Multi-coated glass blocks and prevents the harmful effect of UV rays and eliminates haze that can register a bluish cast from scenic ... How to finish a 4 strand braidReferences zuiko lenses — single vs. multi coating? การเคลือบผิวเลนส์ เกร็ดความรู้….เลนส์ Olympus OM Zuiko.Fully Multi Coated Optics For a pair of binoculars that's great for both astronomy and long-distance terrestrial observation, you'll want the saxon 20x80 Night Sky Waterproof Binoculars. Images will come up bright, clear and crisp with these binoculars' large, oversized 80mm objective lens with anti-reflection coatings, BaK-4 prism and fully ... A119S Dashcam F1.6 v1 Lens vs F1.8 v2 Lens Comparison Original 7G F1.6 v1 Lens = 98 degree HView, uncoated lens, metal base, blurry on left issue/soft focus New F1.8 v2 Lens = 101 degree HView, coated lens, plastic base, great focus. (discovered new F1.8 Lens has.Jan 01, 2008 · A thin anti-reflective coating (usually of magnesium fluorite) on one or more of the lens surfaces. Fully coated. At least one thin anti-reflective coating on both sides of the objective lens system, both sides of the ocular lens system, and the long side of the prism. Multi-coated. Multiple layers of coatings on one or more of the lens surfaces. High school musical karaoke with troyMost photographers leave a UV filter attached to the lens all the time as a form of protection. But the filter also plays an important role in filtering through UV Haze. Waterproof top coat for easy cleaning, 1 year HOYA USA Warranty, Schott B270 clear glass, 10-layers of HMC multi-coatings, Low-profile....
Multicoating is a development from the older single coating system. The single coats were usually blue or occasionally yellow or red. The idea behind coating a lens is to reduce reflections from the surface and (Surprisingly) increase transmission of light into the glass. The single coatings were not all that efficient al all wavelengths.
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An integrated system of coating layers densely packed using ion-assisted deposition results in a lens surface that is three times harder than the previous generation of hard anti-reflective (AR) coated plastic ZEISS lenses and 35 % harder than AR coated glass ZEISS lenses*.
Features Compact foldable roof prism binocular that fits in your pocket! Fully-coated optics for increased clarity Sleek and fashionable rubber armor built with a unique bridge design Compact, lightweight and ideal for travel, concerts and sporting events Includes carrying case and neckstrap What's in The Box 10x25 Tre
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By coating the surface of the lens, the amount of reflection can be minimized, decreasing flare and ghosting. Different Types of Coatings: coated optics: one or more surfaces coated. fully coated: all air-to-glass surfaces coated. multi-coated: one or more surfaces are multi-layer coated. Single Vision Hard Multi Coated (HMC) Lens The second most common lens type, normally used for the graded vision offered to people without a 20/20 eyesight. This is also one the cheapest type of lens that offers normal radiation protection and eyesight correction from near to distant.
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Aug 24, 2020 · The improved aluminum material increases durability while the multi-element coated glass minimizes lens flare and reflections. The soft rubber clip is easy to adjust and you won’t have to worry about unnecessary scratches on your device.
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On “Re-Lens” orders using a rimless frame, the custom drilling and mounting fees cannot be refunded. * Excluded Lenses: Multifocal Lenses: Bifocal and progressive lens orders may be exchanged or remade one time at no cost within the first 90 days after delivery. Any changes to an order prior to shipping will count as the allowed free ...
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It is an upper mid-range quality lens with a price under $100 for most any budget. Its multi-coated 3-element Apochromatic lenses make it perform as well as the more expensive Barlows for the average astronomer on most telescopes. The reasons this guy won; it is 1.25″ and will fit in 99% of all telescopes. Reverse Aspherical Backside Lenses (RABS). When first developing prescription lenses for VR headsets, we The blue light radiation emitted by digital device screens also interferes with your melatonin production Aside from these VR specific features all our lenses are multi-coated, this...


Cataract is the cloudiness in the lens which stop people from seeing clearly. The symptoms range from reduced vision/blurred vision, double vision, glare or seeing haloes at night and colour become less bright.
Cataract is usually due to aging process but it can occur at a younger age if someone is born with it (congenital), suffer an eye injury, diabetes and those take steroids.
While there may be someone offering magic eye drops ( yet to be proven its efficacy), cataract surgery is still the ultimate treatment at present. Phacoemulsification is the preferred and common way to remove cataract.
It uses ultrasonic handpieces through a small wound (2.75mm) on the eye and the cataract is aspirated from the eye. It is performed under local anaesthesia, very often anaesthetic drop onto the eye. Patient is awake but usually will not feel any pain. After about less than half an hour, the operation finish and the patient can go home the same day.
During the surgery, an intraocular lens (IOL) will be implanted into the eye. Depending on one’s need, Dr Ho. Shu Fen will discuss the type of lens to be inserted. It can be a monofocal lens with proven track record, well tolerated by most and allow one to see far clearly but require one to wear reading classes to read; toric lens implant to correct high astigmatism, multifocal IOL/lens implant to allow one to see far and near but with higher price. Dr Ho will discuss all the pros and cons of this lens choice with patient so that patients will have clear expectations of what can be achieved.


Pros of LED Lighting
LED Lighting is one of the most energy reliable lighting technology readily available today. It uses much less electricity to operate than incandescent bulbs, and even newer LED lighting is just as reliable.
Another benefit of LED lighting is that they can provide the same color and brightness as incandescent bulbs. Therefore, it is similar to using a regular bulb for home lighting as it provides a similar quality, even if it doesn’t provide the same ‘warm’ color. This eliminates the want for introducing added lighting in areas where light sources other than those from LED lighting are used.
So, what is so distinctive about LED technology? The leading distinction between LED bulbs and conventional bulbs is the fact that LEDs don’t make use of any filament, however instead make use of a diode. Incandescent bulbs make use of a filament; this filament is then heated up and burned.
A reason that LED technology makes it possible to utilize only a tiny amount of power is because of how the LED bulbs are made. Unlike conventional bulbs, the LED light is powered by the electrons produced within its semiconductor. With conventional bulbs, the electrons will flow into the filament and then begin the procedure of generating heat.
Another benefit of LED lighting is that it can be modified to almost any color or temperature, so they are ideal for many various purposes. For example, LED lamps can be used to illuminate track lighting, as well as use in wall sconces.
One of the main benefits of LED lighting is the ability to control it with a simple twist of a switch. For example, you can simply improve the lighting in your home by replacing the lights in a room. There is no need to hire an electrician, because you can simply replace the lights conveniently yourself.
The other benefit of LED lighting is that it is extremely simple to install, so it is a cost successful way to improve your home. No matter how small the light source, LED bulbs can supply even more light without the expense of hiring an electrician or electrical contractor.
Finally, LED lighting has quite little impact on the environment. Since it is environmentally friendly, it helps to make our world a cleaner put. Even if you don’t like the thought of greener products, LED lighting does not make your home a green living space.


Bai Chu Electronics (688188): Leader in fiber laser control system transformation and upgrading
The pioneer of fiber laser cutting control system.
The company is the first private enterprise in the development of a complete set of military fiber laser cutting control system in China. With independent software development as the core, the company integrates with hardware such as board cards, bus masters, and capacitor height controllers for sale.
The company’s main business focuses on laser PC-based motion controllers, including servo systems, board systems, bus systems and other related supporting products.
From 2016 to 2018, the company’s revenue / attribution net profit CAGR was 41.
7% / 36.
1%, gross margin is over 80%.
Relying on a high-quality technical team, the company entered a strategic switching period and set sail for high-power new technologies.
Fiber laser cutting tens of billions of markets, domestically produced forces have risen.
Fiber lasers are the third generation of new-type lasers, with a global compound laser growth rate of 24 between 2013 and 2017.
78%, estimated at $ 2.5 billion in 2020.
The scale of fiber laser industry expansion has been above 60% since 2013, reaching 79 in 2017.
At present, domestic production of low-power 南宁桑拿 fiber lasers has basically been achieved, and the number of domestically produced low-power fiber lasers has soared.
High power localization rate 13.
6%, the first decline in imports in 2018.
PC-based motion controllers are the key upstream components of fiber lasers. The domestic compound growth rate in recent years is about 13%, and it is expected to exceed 32 in 2020.
Customers & R & D & products build three moats.
1) Product: The company holds about 60% of the domestic low-power laser processing control system market, and the board / follow-up production-sales ratio has remained at a high level.
2) R & D: In 2018, R & D investment accounted for 11%, and R & D personnel accounted for more than half. The core team came from Shanghai Jiaotong University.
The company has 17 patented 杭州桑拿 technologies, 34 software copyrights, 14 software product registration certificates, 32 reserve patents, five independent research and development technologies such as CAD, CAM, and NC, which have reached the international advanced level and can provide a complete set of laser cutting solutions.
3) Customers: We have cooperated with 500 large laser cutting equipment manufacturers, and active customers account for about 60% of the total number of customers in the industry.
The IPO raised a total of 8.
3.5 billion to cultivate new tracks.
Of which 3.
14 ppm for “Bus Laser Cutting System Intelligent Upgrade Project”, 2.
30,000 yuan for “Superfast Laser Precision Micro / Nano Processing System Construction Project”, 1.
97 ppm is used for “the equipment health cloud and MES system data platform construction project”, 0.
Construction of 83 million USD R & D center
$ 3.9 billion to expand marketing network.
The construction period of the bus & ultra-fast laser project is 3 years, and after the completion of production, it will contribute an annual revenue of 9 in total.
500 million (before tax).
Inquiry interval and investment recommendations: We expect the company’s net profit growth rate to be 11 in 2019-2021.
9%, corresponding to an EPS of 1.
72, 2.00 yuan.
Relative estimation method and comprehensive consideration are given to the company’s PE inquiry range of 27-29 times in 2019, and the inquiry range is 42.
24 yuan / share; the reasonable estimate range after listing is 29-32 times, and the reasonable and reasonable price is 45.
Risk reminders: risk of technology and product development, risk of loss of core technical staff and leakage of core technology, risk of intensified competition in the low and medium power laser cutting market, and risk of market development of the high power laser cutting.


MOON is an innovative solution for very small form factor luminaires requiring both a zoom and a colour mixing function. MOON is a silicone light guide and projection lens based on our experience in stage lighting and entertainment.
It was developed in collaboration with one of our most important customers in the stage lighting market. Since the colors or white colour temperature are mixed using multiple internal reflections inside a silicone rod, the homogeneity of the colour is perfect, even on the most difficult colors. This is the best possible solution for high-end luminaires with a diameter of less than 20 mm.
Please note that as a partner product, it will not be available for all applications. Do not hesitate to contact your sales representative for more information.
MOON being a very innovative and atypical optical solution, you will need some guidelines to prototype and integrate it. We have published a MOON Application Note to help you in this process. This application note covers the main questions you will be facing while designing you upcoming fixture. It covers mechanical integration, qualification of beam angles and LED selection option.
A LED injects light on the base of the light guide. Multiple reflections among the light guide length ensure a perfect light homogeneity on the output surface. The image of the output surface is projected by the lens to create the beam.
MOON L : Imaging lens
As a light guide technology based system, MOON consists of two references :
MOON G : Assembled part containing silicone light guide and two-parts holder
MOON is recommended to be integrated with high power flat top LED. As the light guide technology is capable of color/chip emission mixing, single or multi chip, white or RGBW references can be used.
The input part of the light guide has been designed to fit with up to total 4 mm² LES. Using bigger LES might impact efficacy as a significant part of the light will not be collected by the light guide. To ensure the best possible light collection in the light guide, a distance of 0.1 mm is recommended between the LED and the light guide input. The MOON G holder has been designed to fit LED presenting a 1.3 mm thickness thus presenting a 1.4 mm difference between the PCB surface and the light guide input. When using a LED with a lower thickness, it is recommended to create routed areas on the PCB surface to compensate the difference.
MOON beam angle will vary while adjusting distance between MOON G light guide output and MOON
L lens input. This range has to be kept between 1.95 mm (wide beam) and 8.45 mm (narrow beam).
1.95mm corresponds to MOON G and MOON L in mechanical contact.
8.45mm corresponds to a 6.5 mm distance between the top of MOON G and bottom of MOON L.
Beam angle (°) vs Distance (mm)
Projection Lens is the MOON L DD-FF-T-M .
Available reference is MOON L 22-16-C-7


Don’t dim your world when the sun shines
Standard tinted lenses can protect your eyes from harmful rays but can distort how your eyes perceive colour.
They are ideal for people with light sensitivity, or for when driving in bright sunshine, as your perception of the colours of road signs and traffic lights is unaffected
Available in a range of colours and graduations, Essilor Tints are specially treated to give 100% protection against damaging UV rays, without altering colour perception.
Better vision for all outdoor activities in the sun
A real step forward in quality of outdoor vision for all spectacle wearers. In addition to providing protection against the effects of UV light, Polarising lenses give effective protection against the glare caused by reflected sunlight and numerous benefits for greater comfort and safety for activities outdoors.
- Glare reduction
- Enhanced colour perception
- Improved contrast
- Greater visual comfort
- 100% UVA/UVB protection


In vivo Imaging Facility
- Multi-channel in vivo flow cytometry
Our group developed a multi-channel in vivo flow cytometer, based on confocal design. Contrary to the conventional flow cytometer, the in vivo flow cytometer can provide real-time detection and quantitative information on fluorescently labeled cells while in circulation in a live animal model. As the labeled cells pass through a slit of light focused across a blood vessel, fluorescence is excited. Its confocal detection makes it possible to observe the cell population of interest without the need to extract a blood sample. Furthermore, the same cell population can be tracked continuously and over long periods of time to examine the dynamic changes in the circulation of different types of cells in the same animal. The in vivo flow cytometer has been used to measure the circulation lifetime of different tumor cells and leukocyte populations in the peripheral circulation in response to immunological stress or therapeutic manipulation.
- Whole body imaging system (reflectance mode configuration)
Reflectance imaging is a noninvasive, quantitative method that enables longitudinal studies of physiological changes in individual animals over time. Bioluminescence imaging measures visible light that is emitted by luciferase-driven reactions on the luciferin substrate in the presence of oxygen. Fluorescence imaging quantifies the signal that is emitted by cells and tissues in the animal that have been fluorescently labeled either by transfection (direct insertion of a fluorescent protein promoter into the genome), by direct injection of fluorescence probes or by adoptive transfer of ex vivo isolated fluorescent cell populations. Whole body imaging has been used extensively in cancer imaging, to image the development of implanted tumors in mice, and to monitor metastasis and response to therapeutic intervention. In conjunction with the in vivo flow cytometer, the whole body system has also been employed to investigate the biodistribution and homing kinetics of therapeutic delivery vehicles (microparticles) in animal models. These optical techniques afford the opportunity to quantitatively monitor microparticles in circulation, to detect and image their biodistribution and incorporation in cells and organs of healthy and tumor bearing mice, as well as to acquire anatomical information on cancer size and location.


Buying Eyeglasses For Your Eyesight
Regardless of whether you need glasses for your eyesight, you’ll be happy to know that there are many eyeglasses styles available to choose from. There are also a number of different eyeglasses options for people with specific eye conditions, such as myopia or cataracts. In addition, there are eyeglasses with scratch-resistant coatings and progressive lenses.
Choosing the right glasses frame for your face shape is important. It will help balance your face and highlight your unique features. It is also important to ensure that the frame fits well. This will ensure a comfortable and durable fit.
The types of glasses frames available include:
The materials used for making glasses frames vary from metal to acetate. These are durable and can be available in many colors and finishes. They offer style features and are available in different rim types. They are also lightweight.
Glasses frames are fastened to the temples using hinges. Hinge types vary from mechanical hinges to tenon hinges. Mechanical hinges are not as stable as tenon hinges and are less commonly used in high-end technical glasses frames.
The main types of hinges used in glasses frames are tenon hinges, hidden hinges, and spring hinges. Each hinge has threaded loops that protrude from the base of the hinge. The loops are interlocked with screws.
Tenon hinges are typically used for solid full-rim glasses. They are secured with two or three metal rivets. These rivets are placed in a tightly packed cluster on the frame’s front endpiece.
Spring hinges are a modern adaptation of the traditional tenon hinge. These hinges provide a flexible and adaptable mechanism. They are commonly used in low-cost glasses frames. They conceal the spring in the temple half-joint. They are less stable than tenon hinges and may require manual adjustments. They are also more common among reader readers.
The type of material used for making glasses frames can also be important. Acetate is a plastic that is commonly considered to be more environmentally friendly than petroleum-based plastics. It is also available in a variety of colors and patterns. Acetate is also more durable than plastic and can simulate the look of other materials better.
Adding a scratch-resistant coating to your glasses can increase their lifespan and give them a hard, scratch-free surface. However, it’s not a complete guarantee.
Scratch-resistant coatings on glasses are designed to make the lens harder and more resistant to scratches. They are usually applied to both sides of the lens. These coatings are sometimes optional, but they are available with many glasses.
There are many different types of coatings on glasses. These coatings can be expensive, but they do provide a number of benefits. Many coatings are designed to last a long time. For example, a lens with a hydrophobic coating will help prevent your glasses from fogging up in cold conditions. They also repel water and oil.
An anti-glare coating will reduce glare and improve the quality of your vision. This is an important feature to look for when buying glasses. A UV light filter is also an added benefit.
The best way to clean your glasses is by using a microfiber cloth and a lens-cleaning solution recommended by an optician. Never use paper towels to wipe your glasses, or you could end up with a scratch.
An anti-reflective coating is also a good idea. It will reduce glare and give your eyes a rest. However, these coatings are pricier than scratch-resistant coatings, but the benefits are worth it.
An anti-fog coating can prevent your glasses from fogging up when you walk into a warm room or when you perspire. Lastly, an anti-static coating will repel water and oil.
The most important thing to remember is to store your glasses in a case or cushioned bag when they are not in use. Scratches can occur when you drop your glasses, so you want to keep them protected.
Unlike the traditional bifocal, progressive lenses are truly multifocal that allow you to see clearly at different distances. They also offer a more youthful look.
Progressives are also more comfortable to wear than bifocals. They have a smooth transition from distance to near.
The upper portion of a progressive lens provides clear vision at long distances, while the lower portion provides the strength to see close up. This is the newest lens technology.
Progressives are a good choice for people over 40 years of age who are experiencing presbyopia. They also help prevent the development of farsightedness. They can also be worn by children to prevent myopia.
If you are having trouble adapting to progressive lenses, talk to your optometrist. They can help you pick the best frame and help you select the right lens type for your needs.
There are many different types of progressive lenses, including soft, hard, and computer-specific. The most important thing to keep in mind when choosing the correct progressive lens is your lifestyle and preferences. For example, people who work on computers may want a different pair of glasses for up-close activities.
The American Optometric Association reported that 44.8 percent of glasses ordered online were not prescribed by an eye doctor. A knowledgeable optician can help you find the right lens for your needs and protect your investment.
While a progressive lens is a big step forward in eyewear technology, it is not for everyone. Some people may never adjust. Others may require a month or more of adaptation. Luckily, quality optical shops can help you find the right frame and lens. The more you know about eyeglasses, the more comfortable you will be wearing them.
Approximately half of all young adults in the United States and Europe are nearsighted. Myopia is caused by a refractive error, which is a bend in the light rays that focuses them in front of the retina.
Myopia is usually corrected by wearing glasses or contacts. In some cases, surgery can correct the problem. In more serious cases, blindness may occur. A person with high myopia may also develop cataracts. In these cases, surgery can be performed to reshape the eye’s cornea.
Children’s vision continues to change as they grow. They may need to have their eyes tested more often as they reach different stages of development. Children can also be referred to a pediatric ophthalmologist if they have vision issues. Children’s eye exams may include pictures, eye chart tests, and a physical examination.
Most schools conduct eye screenings. However, these tests are often not complete enough to diagnose myopia. Usually, the eye care provider will use a phoropter to test vision. If the doctor finds myopia, he or she will recommend a way to control it.
Nearsightedness can be prevented by wearing glasses only during long-distance viewing and taking breaks during the day. Taking breaks during the day is important because wearing glasses can interfere with the eye’s ability to adjust when looking at close objects.
Eye drops may also be used to prevent nearsightedness. However, it is important to see an eye care provider as soon as you suspect you have nearsightedness. The American Academy of Ophthalmology recommends annual eye exams for people with myopia.
The Mayo Clinic offers extensive background on myopia as well as actionable guidance. It also provides current clinical trials and research on myopia.
Prescription for children
Buying prescription glasses for children is not as simple as you might think. You have to be careful to look for the best features and find a retailer that can meet your child’s specific needs.
There are many different online retailers that sell glasses for kids. Many of these stores offer similar quality glasses as you would find at a doctor’s office.
The best sites to look for glasses for kids are those that accept vision insurance plans. Make sure to read their policies before committing to a purchase. Also, check to see if they offer any manufacturer rebates.
For example, many online retailers have virtual try-on options. This feature makes it easy to see how the glasses look on your child. You can also check customer reviews to see how others like the glasses you’re considering.
Another great feature of many online retailers is that they offer customizable frames. This means you can pick the frames that look the best for your child. You can also find frames that are trendier and more stylish than those you might find in a store.
Another feature you might want to look for is a site that offers free replacement glasses for kids. Most retailers that sell prescription glasses for kids don’t offer this feature.
There are also sites that offer blue light-blocking glasses for kids. These glasses are designed to block the blue light from reaching your child’s eyes, which can help them sleep better. These glasses are available in both prescription and non-prescription versions.
If you’re looking for prescription glasses for kids, then you’ll probably need to make an appointment at your local eye doctor. Some pediatric hospitals offer optical services, but you’ll want to check with your child’s doctor to make sure it’s a good fit.
Health A to Z. (n.d.). HSE.ie. https://www2.hse.ie/az/
U.S. National Library of Medicine. (n.d.). https://www.ncbi.nlm.nih.gov/
Directory Health Topics. (n.d.). https://www.healthline.com/directory/topics
Health A-Z. (2022, April 26). Verywell Health. https://www.verywellhealth.com/health-a-z-4014770
Health Conditions A-Z Sitemap. (n.d.). EverydayHealth.com. https://www.everydayhealth.com/conditions/


The Labino® BigBeam Helios UV Led Duo Power is a portable lamp based on UV LED technology. The lamp is battery operated, but it is possible to run the unit via mains while charging the battery. The light emitting diodes emit a beam of light that is “evenly” distributed. The lamp is available in two different beams – Midlight and Floodlight. The Labino® BigBeam Helios UV Led is 100% free from UV-B. The diodes emit almost no visible light1. Its compact size makes it easy to work with and with an instant-start function you get full power immediately. At a distance of 380 mm the Labino BigBeam Helios UV Floodlight has an initial intensity of approximately 5 500 µW/cm2. The Midlight version has an initial intensity of approximately 8 500 µW/cm2 (the intensity goes down with approximately 500 µW after it has been warmed up).
Midlight ≈ 8 500-8 000 μW/cm2 at 38 cm (15 inches)
Ø 275 mm (total area with a mini-mum intensity of 1200 μW/cm2 at 38 cm)
Take advantage of over 50 years combined experience from our sales team.
International equipment supplier Oceanscan has added underwater acoustic positioning technology from Sonardyne International Ltd. to its rental fleet.
Oceanscan sister company Sercal are proud and excited to be sponsors of the University of Wolverhampton's new 2018 Formula 3 racing car!
Denmore Road, Aberdeen
Oceanscan Ltd (Southern Office)
Orbis Energy Centre, Wilde Street
Lowestoft, NR32 1XH
Tel: +44(0)1502 509247
Oceanscan Ltd. is registered under the Scotland Companies Act 2012 - Registration No. 116255 - VAT registration No. 498 4896 57
Copyright 2017 Oceanscan Ltd. All Rights Reserved.


The study of the function of Ca2+ ions inside cells is one the most dynamic areas of modern cell biology. Ca2+ is known to control neurosynaptic transmission, secretion of hormones, muscle contraction, and a myriad of physiological functions. It is suspected to be involved in cell division, movements of non-muscle cells, as well as memory and learned patterns of the nervous system. In all cases, localized fluctuations in cytosolic free Ca2+ levels inside cells are believed to control these functions. Techniques for the measurement and manipulation of Ca2+ are therefore crucial and have been advancing rapidly largely as a result of invention of fluorescent ion indicators.
We list our fluorescent calcium indicators by grouping them according to the color of the light they emit on binding calcium, namely Red, Green, and Near UV. We also sell non-fluorescent BAPTA derivatives.
Standard instrumentation is readily available in most laboratories and core imaging facilities for compatibility with the multitude of green fluorescent probes in the market. Photochemical constraints and low quantum yields have contributed to the relatively small amounts of red-emitting probes compared to the green-emitting probes.
Red-Emitting Fluorescent Calcium Indicators
Our new red calcium indicator, Ion Red Calcium 660 (IRC-660) is under development. Upon completion, this product will have properties that exceed the normal criteria for fluorescent calcium indicators:
- Good loading
- Good quantum yield
- Great pKa
- Good extinction coefficient (22,000)
Advantages over green emitting fluorescent indicators1
The Red-emitting wavelength region is attractive for biological research because it affords:
- Higher tissue penetration due to reduced scattering and reduced absorption by endogenous fluorophores (usually green)
- Lower phototoxicity
- Reduced spectral overlap by spectrally broad autofluorescence
- Work in an optical window where water and hemoglobin absorption is reduced
- Monitoring Ca2+ in cells or tissues expressing yellow or green fluorescent protein or labelled with other green-emitting fluorophores
These advantages will make the dye usable in almost all cells and hence widen the scope of screening tremendously.
Table 4.1 Ion Indicators Calcium Indicators
|ION Calcium Red 660 K+ Salt||1056||580 nm||660 nm||40||0.400||H2O||5.7|
|ION Calcium Red 660 AM||1190||*||*||*||*||DMSO||*|
*The AM is for non-invasive loading and generates the salt inside the cell by non-specific esterases.
Protocol- to be written by Dr. Joe Kao (U. Maryland).
Modifications of IRC-660 can be made for other applications upon request in a CUSTOM SYNTHESIS.
Green-Emitting Fluorescent Calcium Indicators
Most useful and inexpensive lasers operate in the green part of the visible spectrum and that has made green-emitting fluorescent calcium indicators very useful for confocal microscopy, flow cytometry, and screening. The popular green-emitting fluorescent calcium indicators for screening are FLUO-2, FLUO-3 and FLUO-4. They are all derived from the original FLUO compound (Figure 1) invented by Minta and Tsien (1989).2
|FLUO-2||x = H||R = CH3|
|FLUO-3||x = Cl||R = CH3|
|FLUO-4||x = F||R = CH3|
Table of Properties for FLUO-2, FLUO-3, and FLUO-4
|Indicator||MW||Excitation (nm)||Emission (nm)||Kd||Extinction||Solubility|
|FLUO-2 K+ Salt||891||490||515||230||80,000||H2O|
|FLUO-3 K+ Salt||960||506||526||390||80,000||H2O|
|FLUO-4 K+ Salt||927||490||515||345||80,000||H2O|
Near UV (Traditional) Calcium Indicators
We offer Fura-2 (Figure 1) as a traditional calcium indicator which emits near UV. Fura-2 is very useful because it is ratiometric. It displays a shift in fluorescence upon binding calcium and the ratio of the two wavelengths can be used to effect calibration. The ratiometry figure below (Figure 2) makes it useful even though the excitation ratio is in the UV region where the energy is very high and there is great autofluorescence.
Ca2+ indicators that are excited at visible wavelengths have advantages over UV-excited indicators. Whereas UV light can cause cell damage, visible light is generally biologically benign. Moreover, much less cellular autofluorescence is excited by visible light than by UV light. The ready availability of low-cost lasers that emit visible light makes the visible indicators ideal for confocal microscopy and flow cytometry.
- Oheim M, Hoff MV, Feltz A, Zamateeva A, Mallet J-M, Collot M (2014), New red-fluorescent calcium indicators for optogenetic, photoactivation, and multi-color imaging. Biochimica et Biophysica Acta.
- Minta A, Tsien R (1989), JBC 264, 8171.


Home security is a top priority for many homeowners. We want to protect our families and possessions, especially when we’re away or sleeping. One essential tool is the security camera – but what good is a camera that can’t see in the dark? That’s where night vision comes in. In this post, we’ll take a deep dive into night vision technology and how it allows security cameras to keep watch even after the sun goes down.
An Overview of Night Vision
Night vision refers to the ability to see in low-light conditions. Humans have limited natural night vision compared to many animals. But with technological aids like night vision devices, we can enhance our ability to see in the dark. Night vision is made possible thanks to physics and biology.
Certain materials are able to emit photons – packets of light energy – when exposed to an electric current. Electrons get boosted to a higher energy level and then release photons when they return to their natural state. The photons that are released are in the infrared spectrum, which is invisible to the human eye. But with the right equipment, these photons can be detected and converted into visible light.
The human eye also contains rods and cones. Cones are color receptors activated by visible light. Rods handle peripheral and night vision but need very low light levels to function. Night vision devices amplify the available light to boost the rod cells’ response. This enhances the natural night vision capacity of our eyes.
How Night Vision Security Cameras Work
Night vision security cameras have additional technology to enable 24-hour surveillance. Here are the main components and functions:
- Infrared Illuminator: This is an IR LED light source that emanates infrared light, illuminating the camera’s field of view. It’s invisible to the naked eye but detectable by the security camera. The wavelength is specially matched to be sensed by the camera’s image sensor.
- Image Sensor: The camera’s image sensor is specially engineered to be sensitive to infrared wavelengths from the IR illuminator. It can capture crisp images in very low ambient light. The sensor converts the photons into a digital signal to form the video image.
- Low Light Image Processing: The camera’s processor includes algorithms to enhance low light footage. Techniques like overlaying multiple frames can reduce noise and increase details in dim conditions.
- Infrared Cut-off Filter: A filter blocks visible light from entering the sensor so only IR wavelengths get through. This improves image quality and contrast for the night vision footage.
- High Resolution Image: Night vision security cameras are able to capture high definition footage in dark settings. Many models offer at least 1080p resolution for sharp images and detail.
- Wide Dynamic Range: WDR technology helps balance bright and dark areas in the same scene. This reveals details that would normally be lost in shadows or highlights.
- IR Illuminator Range: The IR illuminator can disperse infrared light across distances of up to 150 feet or more. The range depends on the power of the infrared LEDs and camera specifications.
Types of Night Vision Cameras
There are a few main technology categories when it comes to night vision in security cameras:
This is the most common type of night vision. The camera uses an IR cut filter and IR LED illuminator to capture video in low ambient light. NIR cameras provide between 20-30 meters of night vision.
Thermal cameras detect temperature differences and do not need IR illumination. They can see in total darkness and through obscurants like smoke, fog, or foliage. Thermal imaging has a long range but lower resolution.
Intensifier night vision amplifies any available ambient light. Stars, moonlight, or streetlights are intensified to provide usable images in very dark settings. But no IR illuminator is used.
Infrared and Visible Light
Dual camera systems have separate IR and visible light cameras. Video analytics can merge the feeds for simultaneous night and day vision. But the cameras are more expensive.
Key Features and Benefits of Night Vision Security Cameras
There are many good reasons to invest in night vision for home security:
- 24-hour surveillance – No lapse in coverage means full monitoring day and night. The camera isn’t blind after dark.
- Increased safety – Better visibility at night helps deter crime and gives insight into any activity on your property.
- Peace of mind – You’ll rest easy knowing your home is protected at all hours. Night vision provides that added security.
- High-quality images – Night vision footage is clear, sharp, and detailed even in pitch black. Many models offer full 1080p HD resolution.
- Long detection range – IR illuminators extend detection from 20 to 150 feet or more. The camera can cover large areas at night.
- Motion alerts – Intelligent motion detection can send alerts with video clips when movement occurs in the dark.
- Lower costs – No need for expensive constant lighting. Night vision cameras see in the dark on their own.
- Flexibility – Night vision models can be used indoors and outdoors. They work in all low light settings.
- Smart home integration – View night vision feeds on your smartphone and integrate cameras with other smart devices.
Positioning Tips for Security Cameras with Night Vision
Proper placement is key to getting the most out of your night vision security cameras. Follow these tips for optimal coverage:
- Angle cameras to capture key areas like entryways, driveways, and backyard patios. Consider motion detector floodlights near doors.
- Avoid pointing cameras into sunlight or reflective surfaces that could cause glare and overexposure.
- Locate cameras under eaves or other covered spots to avoid precipitation and spider webs on the lens.
- Elevate cameras for a wider vantage point if possible. Higher mounting spots like second floors and poles can expand the viewing angle.
- Consider overlapping multiple camera views to reduce or eliminate blind spots in the coverage area.
- Adjust the IR illuminator angle to reach outward toward the key areas under surveillance.
- Test night vision performance after installation and make adjustments to ensure optimal visibility.
- Set up alerts and remote access to view and respond to nighttime activity when it occurs.
Proper set up together with high-performance night vision technology allows continuous monitoring and protection of your property after dark. Give yourself peace of mind with cameras that never stop watching.
We hope this overview has provided useful insight into how night vision works in modern security cameras. The technology grants an extra set of virtual eyes on your home 24 hours a day. Talk to a security professional about implementing an automated camera system suited for your needs and budget. With the right equipment, you can rest easy knowing your family and home are protected day and night.
Contact Callaway Security if you’re around North and Central Georgia.


Mirror - Concave/convex (10)
Description / Mirror - Concave/convex (10)
One side concave, one side convex, 100mm square. Interior mirror 70mm diameter. High quality mirror finish, protected with peel off film. Packet of 10.
A mirror that bulges outwards is called a convex mirror. Convex mirrors show things the right way up and usually smaller.
A mirror that bulges inwards is called a concave mirror. How you appear in a concave mirror depends on how close you are to it. From close you look bigger and right way up. Further away you look smaller and upside down.
An object placed between two mirrors can generate many images.
|Alternative Codes||E2D006 F2D006 H2D006 L2D006 M2D006|