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What is the basic principle of LCD display?


The principle of LCD display:

The principle of the LCD display is to use the physical characteristics of the LCD. When the electricity is turned on, the arrangement becomes orderly, so that the light can easily pass through; Use this principle to make a LCD display.

In terms of scope of use, LCD displays can be divided into notebook computer (Notebook) LCD displays and desktop computer (Desktop) LCD displays. NotebookLCD is the most popular LCD display product we see in China at present. It is integrated with other parts of the notebook computer, and it brings convenience to notebook computer users with its lightness and compactness. DesktopLCD is an alternative product of traditional CRT display, which is relatively rare in China at present. Although both of the above are LCDs, the difference is quite large in comparison.

Brightness can be said to be the biggest difference, and users can easily perceive it. The acceptable brightness standard of DesktopLCD is 150cd/m2 (cd/m2 is a unit to measure brightness). Several DesktopLCDs that are currently advertised in China, such as AcerFP555, PHILPS151AX, Samsung520TFT, etc., have a brightness of around 200cd/m2. Already on par with CRT monitors. The brightness of Notebook LCD is usually about 100cd/m2, which is naturally much darker than CRT monitors. This is why it is difficult for us to see the images of Notebook LCD when the ambient light is too strong.

Secondly, the viewing angles (ViewingAngle) of the two LCDs are also different. The viewing angle of the LCD refers to the viewing angle of the display with a contrast ratio greater than or equal to 10. For the same viewing angle, the greater the contrast, the better the visual effect. DesktopLCD requires a larger viewing angle than NotebookLCD.

In addition, many Notebook LCDs cannot automatically adjust the size of the image to fill the screen when the resolution changes, so when running the notebook computer at a certain resolution, we will see that only the center of the screen has an image. DesktopLCD does not have this problem.

According to the physical structure, LCD can be divided into dual scan passive matrix display (DSTN-LCD) in passive matrix display and thin film transistor active matrix display (TFT-LCD) in active matrix display.

DSTN (DualScanTortuosityNomograph) dual-scanning twisted array is a kind of LCD. The LCD display composed of this LCD has poor contrast and brightness, small viewing angle and less rich colors, but its structure is simple and cheap, so it still exists. market.

TFT (Thinfilmtransistor) thin film transistor means that each LCD pixel on the LCD display is driven by a thin film transistor integrated behind it. Compared with DSTN-LCD, TFT-LCD has the characteristics of fast screen response, high contrast and brightness, large viewing angle, rich colors, etc. It overcomes many inherent weaknesses of the former and is currently the mainstream display device for DesktopLCD and NotebookLCD. .