Dot pitch

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Color displays express dot pitch as a measure of the size of a triad plus the distance between the triads.

Dot pitch (sometimes called line pitch, phosphor pitch or pixel 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) of the same color on the inside of a display screen. In the case of a color display dot pitch is a measure of the size of a triad plus the distance between the triads.

Dot pitch may be measured in linear units, usually millimetres, with a smaller number meaning closer spacing, or in dots per linear unit, for example dots per inch, with a larger number meaning wider spacing. Closer spacing generally produces a sharper image (as there are more pixels in a given area). However, other factors may affect image quality, including:

measurement method not documented, complicated by general ignorance of the existence of multiple methods
pixel spacing varying across screen area (e.g., increasing in corners compared to center)
differing pixel geometries
differing screen resolutions when attempting to judge picture quality
tightness of electron beam focus and aim (in CRTs)
differing aspect ratios

Traditionally, dot pitch in displays has been measured on the diagonal, as this gives the most accurate representation of image quality. Starting about the mid-1990s, however, some companies introduced a horizontal dot pitch as a marketing ploy^{[citation needed]}. By measuring only the horizontal component of the dot pitch and ignoring the vertical component, even a cheap, low-quality monitor could be awarded a small-seeming dot pitch.

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 smallest dot pitch at the current time is 0.099 mm.

The above dot pitch measurement do not apply to aperture grille displays. Such monitors use continuous vertical phosphors band 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'.

1 Common dot pitches in monitors
2 Common dot pitches in printers
3 Common dot pitches in scanners
4 See also
5 External links

[edit] Common dot pitches in monitors

LCD screens larger than 15 inches
Display resolution	Megapixel	Aspect Ratio	Screen size	Pixel pitch	Pixels per inch
1024×768 (XGA)	0.78	4:3	15 in	0.297 mm	85.5
1024×768 (XGA)	0.78	4:3	17	0.337	75.3
1280×768 (WXGA)	0.98	5:3	15.4	0.262	96.9
1280×800 (WXGA)	1.01	16:10	12.1	0.204	124.7
			13.3	0.224	113.5
			14.1	0.237	107.1
			15.4	0.259	98.0
			17	0.286	88.8
1280×1024 (SXGA)	1.31	5:4	17	0.264	96.2
			18.1	0.280	90.7
			19	0.294	86.3
1440×900 (WXGA+)	1.29	16:10	14.1	0.211	120.4
			15.4	0.230	110.4
			17	0.254	100.0
			19	0.285	89.1
1400×1050 (SXGA+)	1.51	4:3	15	0.214	118.6
1400×1050 (SXGA+)	1.51	4:3	20.1	0.292	87.0
1680×1050 (WSXGA+)	1.76	16:10	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	4:3	15	0.191	132.9
			20.1	0.255	99.6
			21.3	0.270	94.0
1920×1200 (WUXGA)	2.30	16:10	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
2560×1600 (WQXGA)	4.09	16:10	30	0.250	101.6
3840×2400 (WQUXGA)	9.21	16:10	22.2	0.125	203.2