Philips 150P user manual Q What is Liquid Crystal Display?

FAQs (Frequently Asked Questions)

Q:What is Liquid Crystal Display?

A:A Liquid Crystal Display (LCD) is an optical device that is commonly used to display ASCII

characters and images on digital items such as watches, calculators, portable game consoles etc. LCD is the technology used for displays in notebook and other small computers. Like light-emitting diode and gas-plasma technologies, LCD allows displays to be much thinner than cathode ray tube (CRT) technology. LCD consumes much less power than LED and gas-display displays because they work on the principle of blocking light rather than emitting it.

Q:How are LCDs made?

A:LCDs are created from two glass plates separated from each other at a distance of a few

microns. Plates are filled with liquid crystal, then seals together. The top plate is colored with a RGB pattern to make the color filter. Then polarizers are glued to both plates. This combination is sometimes called "glass" or "cell." The LCD cell is assembled into a "module" by adding the backlight, driver electronics and frame.

Q:What is the structure of TFT LCD ?

A:The LCD TFT components include:

●Polarizing filter : Regulates in and out

●Glass substrate : With electrodes

●Transparent electrodes : These electrodes with high transparency ratios are used to operate the LCD materials.

●Alignment layer : Films used to align liquid crystal elements in fixed direction

●Liquid crystal

●Spacer : Keeps a consistent gap between two glass plates

●Color filter : Displays all colors with RGB filter

●Backlighting : Sends light to the screen.

In the active matrix LCD, a switching transistor (TFT) and a diode are attached to each of the color elements to turn each element on/off. X and Y electrodes are attached to the same circuit board as the TFT is arranged. Switching signal is impressed on X electrode and video signal is Y electrode.

Q:What is polarization ?

A:Polarization is basically directing light to shine in one direction. Light is electromagnetic wave.

Electric and magnetic fields oscillate in a direction perpendicular to the propagation of the light beam. The direction of these fields is called "polarization direction." Normal or non-polarized light has fields in several directions; polarized light has a field in only one direction.

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