Dot pitch

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Some types of pixel layout showing how pixel pitch is measured.

Dot pitch (sometimes called line pitch, stripe pitch, or phosphor pitch) is a specification for a computer display, computer printer, image scanner, or other pixel-based device that describes the distance, for example, between dots (sub-pixels) on a display screen. In the case of an RGB color display, the derived unit of pixel pitch is a measure of the size of a triad plus the distance between triads.

Dot pitch may be measured in linear units (with smaller numbers meaning higher resolution), usually millimeters (mm), or as a rate, for example dots per inch (with a larger number meaning higher resolution). Closer spacing produces a sharper image (as there are more dots in a given area). However, other factors may affect image quality, including:

  • Undocumented or inadequately documented measurement method, complicated by ignorance of the existence of different methods
  • Confusion of pixels and subpixels
  • Element spacing varying across screen area (e.g. widening in corners compared to center)
  • Differing pixel geometries
  • Differing image and pixel aspect ratios
  • Miscellanea such as Kell factor or interlaced video

The exact difference between horizontal and diagonal dot pitch varies with the design of the monitor (see pixel geometry and widescreen), but a typical entry-level 0.28 mm (diagonal) monitor has a horizontal pitch of 0.24 or 0.25 mm, a good quality 0.26 mm (diagonal) unit has a horizontal pitch of 0.22 mm.

The above dot pitch measurement does not apply to aperture grille displays. Such monitors use continuous vertical phosphor bands on the screen, so the vertical distance between scan lines is limited only by video input signal's vertical resolution and the thickness of electron beam, so there is no vertical 'dot pitch' on such devices. Aperture grille only has horizontal 'dot pitch', or otherwise known as 'stripe pitch'.

Common Dot Pitch sizes[edit]

LCD bigger than 15 inches
Resolution Display Megapixel Screen Size Pixel pitch Pixels per inch
1024×768 (XGA) 0.78 15 0.297 85.5
1280×768 (WXGA) 0.98 15.4 0.262 96.9
1280×800 (WXGA) 1.01 15.4 0.259 98.0
17 0.286 88.8
1280×1024 (SXGA) 1.31 17 0.264 96.2
18.1 0.280 90.7
19 0.294 86.3
1440×900 (WXGA+) 1.29 15.4 0.230 110.4
17 0.254 100.0
19 0.285 89.1
1400×1050 (SXGA+) 1.51 15 0.214 118.6
20.1 0.292 87.0
1680×1050 (WSXGA+) 1.76 15.4 0.197 128.9
17 0.218 116.5
19 0.244 104.0
20.1 0.258 98.4
21 0.269 94.4
22 0.282 90.0
1600×1200 (UXGA) 1.92 15 0.191 132.9
20.1 0.255 99.6
21.3 0.270 94.0
1920×1200 (WUXGA) 2.30 15.4 0.173 146.8
17 0.191 132.9
23 0.258 98.4
24 0.270 94.0
25.5 0.287 88.5
27 0.303 83.8
2560×1440 (WQXGA) 3.68 27 0.233 108.8
2560×1600 (WQXGA) 4.09 30 0.250 101.6
3840×2400 (WQUXGA) 9.21 22.2 0.125 203.2

Bolded screen sizes indicate primarily laptop use.

References[edit]

External links[edit]

  • PPI calculator – Shows dot pitch
  • Megapixel Calculator – Identifies aspect ratio and displays photo and video storage requirements for different formats at a given megapixel number