Purpose/Function of Liquid Crystal Display (LCD)
Purpose
Numbers, characters and other symbols can be displayed by liquid crystal displays (LCDs). They are therefore used as output units of electronic Systems. They are being increasingly used as a replacement for conventional analog pointer instruments and indicator lamps.
Function (principle)
The functional principle of the liquid crystal display is explained by the example of a seven-segment display (of illustration). A spacer (d) which envelopes the thin liquid crystal (e) is located between the glass plates (a) and (f). Translucent electrodes (segments) in the form of required symbols are attached to the glass plate (a).
The translucent electrode (h) is located on the glass plate (f). If a voltage is now applied between the connector (g) of the counter-electrode (h) and one or more connectors (b) of the segmented electrodes, (c), the liquid crystal between the counter-electrode (h) and the live electrodes (c) changes its optical properties. If you now look at the arrangement in the direction of the arrow, the surfaces of the live electrodes (c) appear dark and therefore visible. All numbers can therefore be shown by actuating the electrodes (c) accordingly.
The liquid crystal display is also provided with 2 polarization filters (i). Such types of displays have a better contrast and manage with a lower supply voltage (approx. 1.5 - 5 V).
Other symbols can also be displayed if a different arrangement or form of electrodes is chosen. In particular strip-shaped electrodes are used on the multifunction display (A1p13). Strip-shaped electrodes are located on each of the two glass plates (a) and (f). The strips on the glass plate (a) are perpendicular to the strips on the glass plate (f). Individual dots (pixels) can now be actuated by means of this arrangement. If various dots are actuated repeatedly in sequence at sufficient speed, almost any <