What are the LCD screens of LCD TVs?

Technically, LCD panels can be divided into two camps: VA soft screen and IPS hard screen.

1, VA soft screen

VA is called vertical alignment panel, which can provide 16.7M color and large viewing angle. The front contrast of VA panel is the highest, but the uniformity of the screen is not good enough, and color shift often occurs.

2, IPS hard screen

IPS panel technology is a LCD panel technology introduced by Hitachi at 200 1, commonly known as "super TFT". The biggest feature of IPS is that the two poles are on the same plane and arranged in three dimensions. Because the electrodes are on the same plane, the liquid crystal molecules are parallel to the screen in any state, which will reduce the aperture ratio and light transmittance.

Working principle of LCD screen

The basic principle of LCD is that liquid crystal is placed between two conductive glass substrates. Under the action of two electrodes of the upper and lower glass substrates, liquid crystal molecules are distorted, which changes the polarization state of the light beam passing through the liquid crystal box and realizes the on-off control of the backlight beam.

LCD technology changes the brightness according to the voltage, and the color displayed by each LCD subpixel depends on the color screening program. Because liquid crystal itself has no color, color filters are used to produce various colors instead of sub-pixels. Sub-pixels can only adjust the gray level by controlling the passing intensity of light. Only a few active matrix displays are controlled by analog signals, and most of them are controlled by digital signals.

Most digitally controlled LCD screens use an eight-bit controller, which can generate 256 shades of gray. Each sub-pixel can represent 256 levels, then 2563 colors can be obtained, and each pixel can represent 16,777,216 colors.

The human eye's perception of brightness is not linear, and the human eye is more sensitive to the change of low brightness, so this 24-bit chromaticity can not fully meet the ideal requirements. Engineers use the method of pulse voltage adjustment to make the color change look more uniform.