Due to the special structure and performance of LCD devices and modules, certain special requirements must be followed in application:
1. Connection process of LCD
The liquid crystal display device is composed of two pieces of glass. The outer lead is made by photoetching the transparent conductive film attached to the surface, so the traditional welding process cannot be used. At present, the following connection processes are commonly used:
(1) conductive rubber connection
This is a more traditional way. The conductive rubber strip is called zebra conductive rubber strip. It consists of a layer of conductive rubber, one layer of insulating rubber is laminated into a very thick piece, and then cut into strips in the direction perpendicular to the surface.
(2) metal pin connection
The metal is punched into pins, which are fixed at the external lead end of the liquid crystal display device first, and can be used by users, or welded or inserted on the circuit board.
(3) soft connection of hot pressed film
Commonly used in calculators and digital communication equipment. The hot pressing conductive connecting belt is polyester film, and a stone ink conductive strip and insulating hot pressing adhesive are printed on the upper interval. When in use, align the conductive adhesive strip at one end with the external lead of the LCD device, and then align the conductive stripe at the other end with the lead end of the circuit board, and then attach, heat and pressurize it. Because it needs a certain pressure and temperature, users need to configure a special hot press.
(4) anisotropic conductive adhesive connection
The so-called anisotropic conductive adhesive is a hot pressed adhesive film as shown in Figure 1. The plastic ball with gold-plated surface is scattered in the adhesive film. After it is clamped between the LCD and the circuit board to be heated and pressurized, the lead wire is connected through the conductive plastic ball due to the thin pressure of the adhesive film. Because the lead wire spacing is large, it will not be horizontally connected in series. So it is called anisotropic conductive connection. Also known as tab connection.
2. Lighting of LCD
Liquid crystal display is a passive display device, which does not emit light by itself, and realizes display by modulating external light, so daylighting is the key technology of liquid crystal display application. Lighting is generally divided into natural lighting, external light source setting and projection light source.
(1) natural lighting
Using natural light is the most convenient, cheapest and energy-saving way. Most of the time, count and portable LCD are based on natural lighting.
(2) external light source setting
The external light source is set to solve the visibility without external light and improve the display effect.
The external light source setting of common LCD devices mainly refers to the back light source setting. The main requirement of backlight setting is that the brightness of surface light source with uniform brightness can be adjusted well, the body is thin and light, the color is accurate, the power consumption is small, and the cost is low.
3. Precautions for use of LCD devices and modules
(1) avoid applying pressure to the device surface;
(2) prevent wave damage;
(3) protect pins;
(4) the device is moisture-proof;
(5) prevent scratches and pollution;
(6) prevent DC current;
(7) UV protection;
(8) use and storage within the specified temperature range;
(9) anti static interference.