Liquid Crystal Pixel
Purpose
Demonstrates how an applied electric field reorients liquid crystal molecules, switching their birefringence on and off between crossed polarizers. Connects molecular-level physics directly to LCD display technology — every pixel on a laptop screen works this way.
Figure 1:
Setup on overhead projector. The 9V battery in the film canister connects to the LC cell, which sits between crossed polarizing filters on the projector stage.
Figure 2:
No voltage applied: LC birefringence rotates the polarization, and light passes through the crossed polarizers. The pixel appears bright.
Figure 3:
Voltage applied: the electric field reorients LC molecules, eliminating birefringence. The crossed polarizers now block the light and the pixel goes dark.
Equipment
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