Quickly understand the LCD segment display

segement LCD displays  itself does not emit light, so we will install lamps as light sources on both sides of the display screen. The name of the segment code liquid crystal originated from the early days when the liquid crystal display screen was first used. It was mainly used to replace the LED digital tube. There is also a backlight panel on the back of the liquid crystal display screen. The light emitted by the backlight panel will enter the liquid crystal layer of thousands of crystal droplets after passing through the first layer of polarization filter.
The liquid crystal layer is orthogonal polarization. Each crystal droplet is contained in a tiny cell structure. There are transparent electrodes between the glass plate and the liquid crystal material.
What is an electrode? First of all, the electrode is divided into rows and columns. At the intersection of rows and columns, the light state of the liquid crystal is changed by changing the voltage. When the electrode in the segment code screen generates an electric field, the liquid crystal molecules will be distorted, thereby refracting the light in it in a regular manner, and then displaying it on the screen through the polarizer filter layer.
If a voltage is added to the segment code screen, the molecules will rearrange and be completely parallel, so that the light will not be twisted, so it is just blocked by the surface filter. In simple terms, the light with electricity will be blocked, and the light without electricity can be refracted.
7 segment screen (it is composed of 7  segments, used to display the numbers 0~9), such as calculators, clocks, etc., the displayed content is basically numbers, and it is relatively simple. Industry segmentation Non-lattice LCD screens are collectively referred to as segment code LCD screens.
The main control chip requirements of segment code LCD screens are low, the software is simple, and the cost of controlling LCD screens and main controls is low. Only a single-chip microcomputer can drive it.
LCD screens usually have three modes: full-transmission, semi-transmission and reflection. Liquid crystal will not emit light actively, and an external light source is required. The light source of the fully transparent liquid crystal comes from the backlight behind the LCD screen; the light source of the reflective liquid crystal comes from the characteristics of natural light reflected through the film. It is reflected to the observer's eyes by the polarizer of the LCD screen; the semi-transmission liquid crystal is between the two, with both light from the back of the liquid crystal and reflected light from the front. Therefore, fully transparent LCD needs to use backlight, reflective LCD does not need backlight, and semi-transparent LCD can use backlight or not. LCD screens without backlight cannot be observed in the dark.
The materials of segment LCD screens are divided into TN, HTN, STN, BTN (ie VATN), FSTN, which are distinguished according to the distortion of liquid crystal. The higher the distortion, the wider the visible area.
There are two display modes: positive display and negative display. Usually, the display effect is usually white background with black text for positive display and black background with negative display.
The driving conditions depend on the selected driver chip. Whether it matches is related to the bias ratio and duty cycle. For example, the commonly used HT1621 chip has a duty ratio of 1/4DUTY and a bias ratio of 1/3BIAS.
Common connection methods include PIN/zebra/hot seal /FPC.
The operating voltage is usually set between 3~5V, and the LCD power consumption is about 10μA.
The temperature range can be set according to the working environment of the LCD, and the widest temperature is about -35℃~85℃.