BASIC OPERATION ON AN LCD SCREEN BY BOYTECH japanz technology A liquid crystal display consists of two substrates that form A ((flat bottle) That contain liquid crystal mixture The inside surface of the flat bottle are coated with a polymer... that is buffed to align molecules of liquid crystal . The liquid crystal molecules align on the surfaces in the direction of the buffing. For twisted nematic devices, the two surfaces are buffed orthogonal to one another, forming a 90º twist of the liquid crystal from one surface to the other. See FIGURE 1. FIGURE 1 This helical structure has the ability to control light. A polarizer is applied to the front and an analyzer/reflector is applied to the back of the cell. When randomly polarized light passes through the front polarizer, it becomes linearly polarized. It then passes through the front glass and is rotated by the liquid crystal molecules and passes through the rear glass. If the analyzer is rotated 90º to the polarizer, the light will pass through the analyzer and be reflected back through the cell. The observer will see the background of the display, which in this case, is the silver-gray of the reflector. When an appropriate drive signal is applied to the cell electrodes, an electric field is set up across the cell. The liquid crystal molecules will re-align with the electric field perpendicularly to the glass surface. The incoming linearly polarized light passes through the cell unaffected and is absorbed by the rear analyzer. The observer sees a black character on a sliver-gray background. See FIGURE 2. When the electric field is turned off, the molecules relax back to their 90º twist structure. This is referred to as a Positive Image, Reflective Viewing Mode. to be continued boy technologySee More (4 photos) Photo
Posted on: Sun, 15 Sep 2013 09:08:12 +0000
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