What is the Working Principle of Segment LCD Display?

The segment LCD screen is a type of LCD display used to show simple information such as numbers, letters and symbols. Its features include:

Fixed Display Content: Each pixel corresponds to a fixed display content and cannot be changed at will.

Simple Structure: Composed of upper and lower glass substrates, liquid crystal materials and electrodes, with low cost.

Low Power Consumption: It only requires a weak current to drive and has extremely low power consumption.

Widely Applied: It is often used in products such as automotive instruments, electronic scales, and watches.

1. Basic Structure

The segment LCD display mainly consists of the following parts:

1)Polarizing films (one upper and one lower): The polarization directions of these two polarizing films are perpendicular to each other (for example, the upper film is in the vertical direction and the lower film is in the horizontal direction).

2) Glass substrate (one piece each on the top and bottom): Carries transparent ITO electrodes.

3) Transparent electrode:

A. Common electrode: Located on one of the pieces of glass, it is shared by the entire screen.

B. Segment electrodes: Located on another piece of glass, they are etched into the fixed shape we want to display, such as each stroke of the number "8". A "8" character is usually composed of 7 segments (7 independent electrodes).

4) Liquid crystal material: Filled in the tiny gap between two pieces of glass.

5) Backlight panel/reflector: Located at the bottom layer, it provides the light source. The segment code screen itself does not emit light and can only be seen through back-lighting or the reflection of ambient light.

2. Drive Mode: AC AC drive

LCD can’t be subjected to DC for a long time, otherwise it will damage the LCD structure.

Therefore, the segment code display uses AC drive (usually 1-100Hz)

The driving methods include:

A.Static drive: high contrast, but with multiple pins.

B.Dynamic drive (1/2, 1/3, 1/4 Duty, etc.): commonly used, reducing the number of pins.

Summary of Principles

The working principle of a segment LCD display can be summarized as follows: by controlling the voltage between electrodes (segments) of a specific shape, the arrangement of liquid crystal molecules in the corresponding area can be changed, selectively allowing the backlight to pass through or not, displaying fixed numbers, symbols, or patterns.

Segment code screen is a non dot matrix display that uses liquid crystal molecules to change the optical path with voltage, drives specific electrodes through AC, and displays black corresponding segments, thereby forming numbers or symbols.

Shenzhen Jingda Display Technology Co., Ltd is focused on manufacturing monochrome LCD display(including segment LCD display, graphic LCD display and PM OLED), TFT display and HMI solution. With the development of LCD display market, JDA continuously innovates its products. After years of experience, JDA is particularly competitive in the field of segment code screens.