Liquid Crystals work with polarized light. I’ll stick to the basic digit segment in a digital watch or calculator.On such a display, the polarizing filters are aligned so that they appear clear. When the voltage is applied between the two printed electrodes o the opposite panels of glass that contain the liquid crystal compound, the crystal begin rotating, and one they get all the way to 90 degrees, that particular segment turns dark.
If the front polarizing filter is reversed, the screen is dark by default. When the crystals are subjected to the same voltage, the 90 degree twist causes them to align so that the segment becomes clear. Some digital watches are deliberate produced with “reverse” front filters in an attempt to look more futuristic.
Read also:How do LCD displays work?
When it comes to color displays, the default arrangement of filters is shown on the left, blocking the back-light from coming through. Over time, we have learned to control the voltage that twists the crystals so that they can be shaded. For color, each pixel is divided into three sub-pixels with color filters of Red, Green, and Blue. When activated to full, all three colors mix to create a white screen.
By utilizing the ability to vary the shading of each sub-pixel, we’re currently able to generate 16 million individually defined colors which exceeds the number that the average human eye can perceive. This “standard” used 24-bits, with 8-bits per color, allowing each color to have a range of 256 levels of brightness. Mixing them all on the screen is what creates the appearance of full color for our eyes.