Why are the LCD screens all black? Not white or other colors?
LCD screens are generally divided into two types: normally white and normally black. The normally black ones include LG's IPS screen, Samsung's SPVA screen, and Taiwan AUO's MVA screen, etc., and their basic principles are the same:
1. Backlight It is a kind of light that is sealed to "all directions" from a point light source. After passing through the light guide plate, the backlight will become very uniform.
3. The "all directions" light will be filtered out when passing through the polarizer. The polarizer will only allow it to pass through the polarizer "horizontally", while those "vertical" cannot pass through.
4. The liquid crystal material is optically active, it will slowly rotate the "horizontal" light
5. When it rotates to 90°, 270°, etc., it can be completely "vertical", and then pass through the filter plate (this TN-type liquid crystal phase matching method filter plate and polarizing plate are 90°), and its brightness It is 100%; and when the rotation becomes 180°, 360°, etc., it will be completely unable to pass through its filter plate, and its brightness will be 0%; the gray scale of the other angles will be between 0-100%.
6. At this time, there is only the brightness color between black and white, so every 3 liquid crystals are a group, and they will pass through the red, green and blue color filter glass to form the three primary colors. 7. Such a group of 3 liquid crystals, 3 colors ( Its ratio is determined by the angle at which the liquid crystal is rotated) superimposed into a desired color, such a group of liquid crystals becomes a pixel.
