A dot-matrix display is an electronic digital display device that displays information on machines, clocks and watches, public transport departure indicators and many other devices requiring a simple display device of limited resolution.
The display consists of a dot matrix of lights or mechanical indicators arranged in a rectangular configuration (other shapes are also possible, although not common) such that by switching on or off selected lights, text or graphics can be displayed. A dot matrix controller converts instructions from a processor into signals which turns on or off lights in the matrix so that the required display is produced.
- A common size for a character is 5×7 pixels, either separated with blank lines with no dots (in most text-only displays), or with lines of blank pixels (making the real size 6×8). This is seen on most graphic calculators, such as Casio calculators or TI-82 and superior.
- A smaller size is 3×5 (or 4×6 when separated with blank pixels). This is seen on the TI-80 calculator as a “pure”, fixed-size 3×5 font, or on most 7×5 calculators as a proportional (1×5 to 5×5) font. The disadvantage of the 7×5 matrix and smaller is that lower case characters with descenders are not practical. A matrix of 11×9 is often used to give far superior resolution.
- Dot matrix displays of sufficient resolution can be programmed to emulate the customary seven-segment numeral patterns.
- A larger size is 5×9 pixels, which is used on many Natural Display calculators.