There is no such thing on the LCD screen, so you can't see any display at all, because when the LCD screen is working, the remaining parallel light can't be seen by the naked eye unless it is polarized by the polarizer.
Polarizer is a soft and thin material. If it is scratched, stabbed or scratched, it will not work in production, so be careful when using it. Although it does not affect the overall display function, it is not so comfortable in appearance, so don't deliberately do harmful actions such as pressing, scratching and stabbing.
So the softer layer is called polarizer, which works with liquid crystal to realize optical rotation and development.
In the production process, people first printed wiring (transparent ITO material) on two ordinary tempered glasses, then coated frame glue on the periphery of the two glasses, aligned and pressed together, then poured liquid crystal between the two glasses to seal the liquid crystal port, and then the next job was to paste a layer of such polarizer on the top and bottom of the glass.
The polarizer attached to the upper glass and the lower glass cannot filter out the light in the same direction at the same time. For example, if the lower polarizer filters light in the X direction, the upper polarizer must filter light in the Y direction. If the filter angles of the upper polarizer and the lower polarizer are the same, the LCD will not be visible to the naked eye when it works. But the LCD is still working normally, but the polarized light is invisible to the naked eye.
At present, color LCD usually has only a top film and no bottom film, which is the result of technical development. . .