question: Difference between physical screen size and resolution
comment: Picture graph paper...the number of intersections (pixels) on the page (screen) ...if you make the page (screen) bigger then the intersections (pixels) get larger and more spaced apart...make the graph more dense by adding more intersecting lines more pixels) you get more places but you don't HAVE to make the paper bigger...yes, typically one goes with the other...but they are separate measurements
passages: Comparison of high-definition smartphone displays
  
  The following is a comparison of high-definition smartphone displays, containing information about their specific screen technology, resolution, size and pixel density. It is divided into three categories, containing smartphones with 720p, 1080p and 1440p displays. 
   On two-dimensional display devices such as computer monitors the display size or view able image size is the actual amount of screen space that is available to display a picture, video or working space, without obstruction from the case or other aspects of the unit's design. The main measurements for display devices are: width, height, total area and the diagonal.
   BULLET::::- Spatial performance: For a computer monitor or some other display that is being viewed from a very close distance, resolution is often expressed in terms of dot pitch or pixels per inch, which is consistent with the printing industry. Display density varies per application, with televisions generally having a low density for long-distance viewing and portable devices having a high density for close-range detail. The Viewing Angle of an LCD may be important depending on the display and its usage, the limitations of certain display technologies mean the display only displays accurately at certain angles.
   The size of a screen is usually described by the length of its diagonal, which is the distance between opposite corners, usually in inches. It is also sometimes called the physical image size to distinguish it from the "logical image size," which describes a screen's display resolution and is measured in pixels.
   BULLET::::- Display resolution: the number of pixels in each dimension on a display. In general a higher resolution will yield a clearer, sharper image.
   One use of the term "display resolution" applies to fixed-pixel-array displays such as plasma display panels (PDP), liquid-crystal displays (LCD), Digital Light Processing (DLP) projectors, OLED displays, and similar technologies, and is simply the physical number of columns and rows of pixels creating the display (e.g. 1920 × 1080). A consequence of having a fixed-grid display is that, for multi-format video inputs, all displays need a "scaling engine" (a digital video processor that includes a memory array) to match the incoming picture format to the display.
   Section::::Current standards.:Computer monitors.:Evolution of standards.
   Graphics display resolution
  
  The graphics display resolution is the width and height dimension of an electronic visual display device, such as a computer monitor, in pixels. Certain combinations of width and height are standardized and typically given a name and an initialism that is descriptive of its dimensions. A higher display resolution in a display of the same size means that displayed photo or video content appears sharper, and pixel art appears smaller.
  
  Section::::Aspect ratio.
   For device displays such as phones, tablets, monitors and televisions, the use of the word "resolution" as defined above is a misnomer, though common. The term "display resolution" is usually used to mean "pixel dimensions," the number of pixels in each dimension (e.g. 1920 × 1080), which does not tell anything about the pixel density of the display on which the image is actually formed: resolution properly refers to the pixel density, the number of pixels per unit distance or area, not "total" number of pixels. In digital measurement, the display resolution would be given in pixels per inch (PPI). In analog measurement, if the screen is 10 inches high, then the horizontal resolution is measured across a square 10 inches wide. For television standards, this is typically stated as "lines horizontal resolution, per picture height"; for example, analog NTSC TVs can typically display about 340 lines of "per picture height" horizontal resolution from over-the-air sources, which is equivalent to about 440 total lines of actual picture information from left edge to right edge.
   Section::::Current standards.:Computer monitors.:2010s.
  
  , 1366 × 768 was the most common display resolution.
  
  In 2010, 27-inch LCD monitors with the 2560 × 1440-pixel resolution were released by multiple manufacturers including Apple, and in 2012, Apple introduced a 2880 × 1800 display on the MacBook Pro. Panels for professional environments, such as medical use and air traffic control, support resolutions of up to 4096 × 2160 pixels.
  
  Section::::Current standards.:Computer monitors.:Common display resolutions.
  
  The following table lists the usage share of display resolutions from several sources, as of May 2019. The numbers are not representative of computer users in general.
   Section::::Optimal screen size and viewing distance.
   Display size
  
  On 2D displays, such as computer monitors and TVs, the display size (or viewable image size or VIS) is the physical size of the area where pictures and videos are displayed. The size of a screen is usually described by the length of its diagonal, which is the distance between opposite corners, usually in inches. It is also sometimes called the physical image size to distinguish it from the "logical image size," which describes a screen's display resolution and is measured in pixels.
  
  Section::::History.
   BULLET::::- Display resolution is the number of distinct pixels in each dimension that can be displayed. For a given display size, maximum resolution is limited by dot pitch.
  
  BULLET::::- Dot pitch is the distance between sub-pixels of the same color in millimeters. In general, the smaller the dot pitch, the sharper the picture will appear.
  
  BULLET::::- Refresh rate is the number of times in a second that a display is illuminated. Maximum refresh rate is limited by response time.
   The eye's perception of "display resolution" can be affected by a number of factors see image resolution and optical resolution. One factor is the display screen's rectangular shape, which is expressed as the ratio of the physical picture width to the physical picture height. This is known as the aspect ratio. A screen's physical aspect ratio and the individual pixels' aspect ratio may not necessarily be the same. An array of 1280 × 720 on a display has square pixels, but an array of 1024 × 768 on a 16:9 display has oblong pixels.
   The PPI/PPCM of a computer display is related to the size of the display in inches/centimetres and the total number of pixels in the horizontal and vertical directions. This measurement is often referred to as dots per inch, though that measurement more accurately refers to the resolution of a computer printer.
   Section::::Considerations.
   BULLET::::- 8K UHD (7680 × 4320 progressive scan)
  
  Section::::Current standards.:Computer monitors.
  
  Computer monitors have traditionally possessed higher resolutions than most televisions.
  
  Section::::Current standards.:Computer monitors.:2000s.
  
  , 1024 × 768 eXtended Graphics Array was the most common display resolution. Many web sites and multimedia products were re-designed from the previous 800 × 600 format to the layouts optimized for 1024 × 768.
   BULLET::::- The closest a hand held screen can comfortably be viewed is 250mm (approx. 10 inches)
  
  Section::::Smallest Visible Pixel Size for a Hand Held Device.
  
  The smallest visible pixel size ("p") for a hand held device can be calculated assuming the screen is held at a comfortable distance (250mm) for someone with "normal" vision (able to see detail at a 1/60 degree angle):
  
  It can therefore be concluded that the pixel size for the Hitachi DX07 screen is only 5% greater than the smallest possible for practical use.
   For example, on the Android operating system a device-independent pixel is equivalent to one physical pixel on a 160 dpi screen, while the Windows Presentation Foundation specifies one device-independent pixel as equivalent to 1/96th of an inch.
  
  As dp is a physical unit it has an absolute value which can be measured in traditional units, e.g. for Android devices 1 dp equals 1/160 of inch or 0.15875 mm.
  
  While traditional pixels only refer to the display of information, device-independent pixels may also be used to measure user input such as input on a touch screen device.
   Programs designed to mimic older hardware such as Atari, Sega, or Nintendo game consoles (emulators) when attached to multiscan CRTs, routinely use much lower resolutions, such as 160 × 200 or 320 × 400 for greater authenticity, though other emulators have taken advantage of pixelation recognition on circle, square, triangle and other geometric features on a lesser resolution for a more scaled vector rendering.
  
  Section::::Current standards.:Computer monitors.:Commonly used.
  
  The list of common display resolutions article lists the most commonly used display resolutions for computer graphics, television, films, and video conferencing.
  
  Section::::See also.
  
  BULLET::::- Graphics display resolution
  
  BULLET::::- Computer display standard
   Monitors do not have dots, but do have pixels; the closely related concept for monitors and images is pixels per inch or PPI. Many resources, including the Android developer guide, use the terms DPI and PPI interchangeably.
  
  Section::::DPI measurement in printing.
  
  DPI is used to describe the resolution number of dots per inch in a digital print and the printing resolution of a hard copy print dot gain, which is the increase in the size of the halftone dots during printing. This is caused by the spreading of ink on the surface of the media.
   BULLET::::- Brightness: The amount of light emitted from the display. It is sometimes synonymous with the term "luminance", which is defined as the amount of light per area and is measured in SI units as candela per square meter.
   Modern HDTV plasma televisions usually have a resolution of 1,024×768 found on many 42 inch plasma screens, 1280×768, 1,366×768 found on 50 in, 60 in, and 65 in plasma screens, or 1920×1080 found in plasma screen sizes from 42 inch to 103 inch. These displays are usually progressive displays, with non-square pixels, and will up-scale and de-interlace their incoming standard-definition signals to match their native display resolution. 1024×768 resolution requires that 720p content be downscaled in one direction and upscaled in the other.
  
  Section::::Design.
   BULLET::::- British media also frequently uses the football pitch for equivalent purposes, although soccer pitches are not of a fixed size, but instead can vary within defined limits ( long, and wide, giving an area of ). However the UEFA Champions League field must be exactly giving an area of or . Example: HSS vessels are aluminium catamarans about the size of a football pitch... - Belfast Telegraph 23 June 2007
  
  BULLET::::- Larger areas are sometimes expressed as a multiple of the areas of certain American states, or subdivisions of the UK etc.
  
  Section::::Non-standard units.:Energy.
   Smartphones use small displays, but modern smartphone displays have a larger PPI rating, such as the Samsung Galaxy S7 with a quad HD display at 577 PPI, Fujitsu F-02G with a quad HD display at 564 PPI, the LG G6 with quad HD display at 564 PPI or – XHDPI or Oppo Find 7 with 534 PPI on 5.5" display – XXHDPI (see section below). Sony's Xperia XZ Premium has a 4K display with a pixel density of 807 PPI, the highest of any smartphone as of 2017.
  
  Section::::Named pixel densities.
  