Liquid Crystal Box (LCD Module) Parameters

The liquid crystal box is the core component of a liquid crystal display (LCD), and the display effect is mainly influenced by the liquid crystal box. The main parameters of the liquid crystal box include transmittance, contrast ratio, viewing angle, response time, driving voltage, and operating temperature. Among them:

• Transmittance: This is the primary parameter of the liquid crystal box, which reflects the efficiency of backlight transmission through the liquid crystal box, jointly determining the brightness of the display.

• Contrast Ratio: It represents the ratio of brightness between the bright state and the dark state (also known as the black state) of the display, reflecting the clarity and vividness of the displayed image.

• Viewing Angle: It characterizes the range of viewing angles at which the display can be viewed with a certain contrast ratio.

• Response Time: It indicates the time required for liquid crystal molecules to switch between the bright state (also known as the white state) and the dark state under pixel voltage driving. A longer response time makes it easier for the human eye to observe trailing effects in the image.

• Driving Voltage: It reflects the driving power consumption of the liquid crystal box and the driving capability of the IC.

• Operating Temperature: It determines the suitable temperature environment for the liquid crystal box.

Common LCD Display Modes

LCD displays operate by controlling the rotation of liquid crystal molecules through electrical signals. Based on the different rotation modes of liquid crystal molecules, LCD displays can be divided into different display modes. The common LCD display modes include:

• Twisted Nematic (TN) Mode: This is the most basic and widespread display mode. In TN mode, the pixel electrode and the common electrode are located on the lower and upper substrates of the liquid crystal box, respectively. Liquid crystal molecules rotate vertically under the control of a vertical electric field to achieve display.

• Vertical Alignment (VA) Mode: This mode also controls the rotation of liquid crystal molecules in the vertical direction to achieve display. The pixel electrode and the common electrode are located on the lower and upper substrates, respectively. Unlike other modes, VA mode uses a vertical alignment method and uses negative liquid crystal.

• In-Plane Switching (IPS) Mode: In this mode, pixel electrodes and common electrodes are located on the same glass substrate and in the same plane. Liquid crystal molecules are controlled to rotate within the plane by a horizontal electric field.

• Fringe Field Switching (FFS) Mode: Similar to IPS mode, liquid crystal molecules also rotate within the plane in FFS mode. However, there is a difference in electrode structure: the pixel electrode and the common electrode are not on the same plane, separated by an insulating layer. The main control of liquid crystal molecules’ rotation in FFS mode is through the fringe electric field formed between the pixel electrode and the common electrode. Additionally, transparent electrodes (ITO) replace the opaque metal layer used in IPS mode, giving FFS mode higher transmittance in addition to the wide viewing angle advantages of IPS mode.