Page 1013 - Basic Electrical Engineering
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Figure 14.50 Numerical display boards using seven segments illuminated by LEDs
Figure 14.51 (a) Cross-section of a liquid crystal cell; (b) LCD
14.13.4 Liquid Crystal Displays
LCDs use liquid crystal cells which has a very thin liquid crystal material
placed between two glass sheets. On the inner side of the glass sheets a
transparent metal film is deposited as shown in Fig. 14.51 (a).
On the surface of the two glass sheets, polarizing optical filters are placed.
The liquid crystal material twists the light passing through the polarizing
filters and the cell looks semi-transparent. When the cell is energized with
