LCD is a flat display technology widely used in electronic Equipment

Working principle

The working principle of the LCD screen is based on the properties of liquid crystal, a special substance. Liquid crystal is a substance between a liquid and a solid, and its molecules have a highly ordered structure. Without an electric field, the liquid crystal molecules will exhibit a specific arrangement that prevents light from passing through.

However, when an electric field is applied to the liquid crystal layer, the arrangement of the liquid crystal molecules changes. This is because the electric field changes the direction of the liquid crystal molecules, causing them to rearrange themselves. By controlling the intensity and direction of the electric field, the arrangement of liquid crystal molecules can be adjusted, thereby changing the degree of light transmission. In this way, an image can be formed.

Structure and composition

LCD screens usually consist of multiple layers:

Backlight: The light source behind the LCD screen, used to provide light to illuminate the entire screen. Traditional LCD screens use cold cathode tubes (CCFL) as backlight sources, while modern LCD screens mostly use LEDs as backlight sources, which are called LED backlight LCDs.

Liquid Crystal Layer: This is the core component of LCD, which contains liquid crystal molecules. The arrangement of liquid crystal molecules is affected by the electric field, thereby controlling the degree of light transmission.

Color Filter: Located above the liquid crystal layer, it is used to separate white light and generate three basic colors of red, green, and blue. The combination of these colors creates the various colors on the screen.

TFT array (Thin Film Transistor Array): Located below the liquid crystal layer, it consists of a large number of thin film transistors, each transistor corresponding to a pixel on the screen. Transistors control the arrangement of liquid crystal molecules, allowing them to pass light or block it.

Glass Substrate: The upper and lower sides of the liquid crystal layer are usually supported by glass substrates to maintain the stability of the screen.

Advantages and features

Thin and lightweight: Compared with traditional CRT monitors, LCD monitors are very thin and lightweight, suitable for use in limited spaces.

Energy-saving and efficient: LCD displays are relatively energy-saving, especially LED-backlit LCDs, which can significantly reduce energy consumption.

Not easy to produce radiation: Compared with CRT monitors, LCD screens produce less radiation and have less impact on users’ health.

Wider viewing angle: LCD screens usually have a wider viewing angle range, allowing users to view the screen from multiple angles without distortion in color and brightness.

Good color performance: LCD screens are better than many other display technologies in terms of color performance, providing bright and rich colors.

Application areas

LCD technology is widely used in various electronic devices:

TV: LCD TV is one of the most common types of TV currently, with excellent picture quality and low energy consumption.

Computer monitors: LCD monitors have replaced many traditional CRT monitors and become the mainstream computer display device.

Laptops: LCD screens are the standard display device for laptops and have the advantages of portability and high resolution.

Mobile phones and tablets: Almost all mobile phones and tablets use liquid crystal technology such as LCD or OLED.

Digital photo frames: LCD screens are also used in digital photo frames to display photos and multimedia content.

Overall, LCD technology plays a vital role in electronic devices, providing users with a high-quality image display experience. With the continuous development of technology, the performance and functions of LCD screens will be further improved, bringing users a better visual experience.