LCD (Liquid Crystal Display), also known as Liquid Crystal Display, is a flat panel display technology widely used in various electronic devices. LCD screens adjust the transmittance of light by controlling the arrangement of liquid crystal molecules, thereby displaying images and text. Compared with early CRT (cathode ray tube) displays, LCD displays have advantages such as small size, light weight, and low power consumption. Therefore, they have been widely used in various devices such as televisions, computer displays, mobile phones, tablets, laptops, digital cameras, and watches.

working principle:

The working principle of LCD display screens is based on the characteristics of liquid crystal materials. Liquid crystal is a material state that lies between liquid and solid, with fluidity and optical anisotropy. In an LCD screen, the liquid crystal layer is located between two parallel transparent electrodes (usually a glass substrate), which are coated with transparent conductive material. When voltage is applied to these electrodes, the arrangement direction of liquid crystal molecules will change, affecting the light passing through.

Structural composition:

A typical LCD display screen mainly consists of the following parts:

Backlight source: Provides a uniform light source, typically using cold cathode fluorescent lamps (CCFL) or LEDs (light-emitting diodes).

Polarizer: located on both sides of the liquid crystal layer, used to control the polarization direction of light.

Liquid crystal layer: containing liquid crystal molecules, the arrangement of molecules is controlled by an electric field to adjust the transmittance of light.

Color filter: located above the liquid crystal layer, used to generate three primary colors of red, green, and blue, and synthesize various colors.

TFT (thin film transistor) array: used to control the switching and brightness of each pixel, ensuring image clarity and response speed.

Driver circuit: responsible for receiving input signals and converting them into an electric field to control liquid crystal molecules.

Type:

According to the different backlight sources, LCD displays can be divided into:

CCFL Backlit LCD: It uses cold cathode fluorescent lamps as the backlight source and is now less commonly used.

LED Backlit LCD: Using LED as the backlight is currently the mainstream LCD technology, with longer lifespan and better energy efficiency.