Liquid crystal display (LCD) is a kind of display. The basic principle is to seal the liquid crystal in a glass box, and then apply electrodes to make it change cold and hot, so as to affect its light transmittance to achieve the effect of light extinction.
At present, common liquid crystal display devices include twisted nematic (TN), super twisted nematic (STN), DSTN (double layer TN) and thin film transistors (TFT). The first three kinds of manufacturing principles are the same, becoming passive matrix liquid crystal, while TFT is more complex, and is called active matrix liquid crystal because it retains memory.
Because LCD has the advantages of small space, thin panel thickness, light weight, flat right angle display, low power consumption, no electromagnetic radiation, no thermal radiation and so on, it gradually replaces the traditional CRT image tube monitor.
LCD displays basically have four display modes: reflection, reflection transmission conversion, projection and transmission.
(1). Basically, the reflective LCD does not emit light by itself. It is injected into the LCD panel by the light source in the space, and then the light is reflected into people's eyes by its reflector;
(2). The reflection transmission conversion type can be regarded as the reflection type when the light source in the space is sufficient, and when the light source in the space is insufficient, the hidden light source is used as the illumination;
(3). Projection type uses the principle similar to film playing, and uses the projection optics system to project the image displayed by the LCD onto a larger screen at the far end;
(4). The transmissive liquid crystal display makes full use of the built-in light source as illumination.
Relevant test conditions of LCD display:
High temperature storage: 60 ℃, 30% RH, 120 hours
Low temperature storage: -20 ℃, 120 hours
High temperature and humidity: 40 ℃, 95% RH (non wetting), 120 hours
High temperature operation: 40 ℃, 30% RH, 120 hours, standard voltage
Temperature shock: -20 ℃ (30 minutes) ↓ 25 ℃ (10 minutes) ↓ 20 ℃ (30 minutes) ↓ 25 ℃ (10 minutes), 10cycle
Note: the tested module should be placed under normal conditions (15 ~ 35 ℃, 45 ~ 65% RH) for one hour before testing
