The light emitting principle of TFT-LCD (Thin Film Transistor Liquid Crystal Display) is based on the optical properties of liquid crystal molecules and the auxiliary lighting of the backlight. The following is a brief description of the light emitting principle of the TFT-LCD display:
- Arrangement of liquid crystal molecules: The TFT-LCD display is composed of two parallel glass substrates, with liquid crystal molecules in the middle layer. Under the action of an electric field, liquid crystal molecules can control their alignment. There is a layer of induced electrode array (TFT array) on the two glass substrates of the LCD screen. By controlling the electric field at each pixel, the alignment direction of the liquid crystal molecules can be controlled.
- Light polarization: The arrangement of liquid crystal molecules will affect the polarization of light. When the liquid crystal molecules are arranged, the polarization direction of light can be rotated or blocked by adjusting the electric field, so as to realize the control of light.
- Backlight: TFT-LCD displays usually need a backlight to provide illumination. The backlight is located behind the LCD screen, and commonly used technologies include cold cathode fluorescent lamps (CCFL) or LED backlights. These backlights will produce uniform white light and adjust the degree of light transmission through the control of liquid crystal molecules.
- Image display: In the operation of the TFT-LCD display, controlling the arrangement of liquid crystal molecules can adjust the degree of light transmission 4 to control the brightness of each pixel. By adjusting the arrangement of liquid crystal molecules, the display of images can be realized. Each pixel in the LCD screen is controlled by liquid crystal molecules and TFT circuits to adjust the degree of light transmission and form visible images under the illumination of the backlight.
To sum up, the TFT-LCD display uses the optical properties of liquid crystal molecules to control the arrangement of liquid crystal molecules by adjusting the electric field, thereby adjusting the degree of light transmission and realizing image display. The backlight provides the illumination to make the image visible on the LCD screen.