Dot pitch (sometimes called line pitch or phosphor pitch) is a specification for a computer display that describes the distance between phosphor dots (sub-pixels) or LCD cells of the same color on the inside of a display screen. Thus, dot pitch is a measure of the size of a triad plus the distance between the triads. Nineteen inch (48 cm) CRT computer monitor A computer display, monitor or screen is a computer peripheral device capable of showing characters and/or still or moving images generated by a computer and processed by a graphics card. ... A phosphor is a substance that can exhibit the phenomenon of fluorescence (glowing during absorption of radiation of another kind) or phosphorescence (sustained glowing without further stimulus). ... A pixel (pix, 1932 abbreviation of pictures, coined by Variety headline writers + element) is one of the many tiny dots that make up the representation of a picture in a computers memory. ... For other meanings see Triad (disambiguation). ...

Measured in millimetres, a smaller number generally means a sharper image, and vice versa, as there are more dots in an area of any given size. Note, however, that a monitor with a smaller dot pitch usually has a better-quality image, but by no means always, due to a number of factors, including: A millimetre (American spelling: millimeter, symbol mm) is an SI unit of length that is equal to one thousandth of a metre. ...

• measurement method not documented, complicated by general ignorance of the existence of multiple methods
• differing pixel geometries
• differing screen resolutions when attempting to judge picture quality
• tightness of electron beam focus and aim

Traditionally, dot pitch was always measured on the diagonal, as this gives the most accurate representation of the monitor. Starting about the mid-1990s, however, some companies introduced a horizontal dot pitch as a marketing ploy. 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. A display with a diagonal dot pitch of 0.25 mm has four dots per linear millimeter, and a 0.20 mm horizontal dot pitch display has five dots per linear millimeter. The components of the pixels (primary colors red, green and blue) in an image sensor or display can be ordered in different patterns, called pixel geometry. ... The 1990s decade refers to the years from 1990 to 1999, inclusive. ...

The exact difference between horizontal and diagonal dot pitch varies with the design of the monitor (see Pixel geometry), 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 a horizontal pitch of 0.22 mm. The components of the pixels (primary colors red, green and blue) in an image sensor or display can be ordered in different patterns, called pixel geometry. ...

Some modern manufacturers quote dot pitch measurements made on the horizontal, others on the diagonal, and many use both. In general, low-end manufacturers tend to quote a horizontal measurement, while quality manufacturers tend to use the diagonal method, but there are many exceptions.

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 are 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'. An aperture grille is one of two major technologies used to manufacture cathode ray tube (CRT) televisions and computer displays; the other is shadow mask. ...

See also

• Pixel
• Pixel geometry discusses how sub-pixels are arranged
• Triad