LCD Screen And LCD Module Use Precautions

- Aug 30, 2018-

               

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Liquid crystal display (LCD):


1. The liquid crystal display (LCD) should prevent the DC component of the DC voltage driving voltage from being applied as small as possible. Do not exceed 50mV at most. If a large DC component is applied for a long time, electrolysis and electrode aging will occur, thus reducing the life.


2. The liquid crystal display (LCD) should be protected from ultraviolet light: the liquid crystal and the polarizer are organic, and photochemical reaction and deterioration occur under ultraviolet irradiation. Therefore, when the liquid crystal display device is assembled, it should be considered according to its use and environment. UV protection filters or other UV protection methods. Avoid long periods of direct sunlight when using.


3. The liquid crystal display (LCD) should be protected from harmful gases: liquid crystals and polarizers are organic substances, which cause chemical reactions and deterioration in the environment of harmful gases. Therefore, isolation measures should be taken to use harmful gases, and the whole machine is assembled. After that, do not store it for a long time to prevent the concentration of chemical gas generated by the plastic case and the circuit board cleaning agent from damaging the liquid crystal and the polarizer.


4. The liquid crystal display device is made of two pieces of glass with only 5 to 10 um between them and is very thin. Moreover, the inner surface of the glass is also coated with an oriented film, which is easily damaged. Therefore, the following points should also be noted: the surface of the liquid crystal device cannot be overstressed to avoid damaging the alignment layer. In case of excessive pressure during the assembly process or by pressing the device, it is necessary to stand for one hour and then power on. Remember that there must be no drastic temperature changes during power-on. The pressure should be uniform when the device is pressed, only the side of the device is pressed, the middle cannot be pressed, and the force cannot be tilted.


5. Since the liquid crystal state will disappear beyond a certain temperature range, it must be stored and used within the specified temperature range. If the temperature is too high, the liquid crystal state disappears and becomes liquid. The display surface is black and cannot work. Please be careful not to pass the power at this time. If the temperature is too low, the liquid crystal begins to form ice, causing permanent damage. In addition, when stored at extreme temperatures for a long time or subjected to vibration and shock, the LCD also generates air bubbles.


6. Prevent glass breakage: Since the display device is made of glass, if it is lost, the glass will definitely rupture, so the design of the assembly and the vibration and impact resistance of the assembly must be tested.


7. Moisture resistance of the device: Due to the low voltage and micro power consumption of the liquid crystal display device, the resistivity of the liquid crystal material is extremely high (up to 1×1010 Ω or more). Therefore, the surface of the glass caused by moisture may cause "string" between the segments when the device is displayed, so the design of the whole machine must consider moisture. Usually, place it at a temperature of 5~30°C and a humidity of 65%.


8. Cleaning treatment of liquid crystal display device: Since the liquid crystal surface is a plastic polarizing plate and a reflective sheet, scratching and staining should be avoided during assembly and storage. In addition, there is a protective film on the front polarizer, which is removed when used. If the surface of the device is dirty, it can be treated with a soft, fine cloth and cotton. If it is necessary to use a solvent to clean, use only isopropyl alcohol (glycerol), alcohol, and freon, and never use acetone or aromatic solvents such as toluene, otherwise the polarizer on the surface of the device will be damaged.


9. In the case of an LCD with metal pins, when soldering the pins, the solder joints should be 4 mm or more from the root and should not be overstressed or overheated to avoid damaging the connections. The maximum temperature resistance at the joint must not exceed


Liquid crystal display module (LCM):


First, the operation notes:

1. The display is made of glass. Do not apply mechanical shock, such as falling from a height.

2. If the display is damaged, the internal liquid crystal leaks, do not let it enter the mouth. If it gets on your clothes or skin, wash it off quickly with soap and water.

3. Do not apply excessive force to the display surface or the connection area of the LCD module as this will cause a change in hue.

4. The polarizing plate on the surface of the LCD module display is soft and easy to scratch and handle carefully.

5. If the surface of the LCD module display is dirty, wipe it with a soft, dry cloth. If it is heavily soiled, wipe it with isopropyl alcohol or ethanol (alcohol) and damp cloth.

6, other solvents may damage the polarizer, especially water, ketones, fragrances and so on.

7. When installing the LCD module using the mounting holes, be sure not to twist, bend and deform. Deformation can have a major impact on display quality.

8. When installing the LCD module, do not forcibly pull or bend the I/O leads or backlight leads.

9. Touching the TAB of the LCD module may cause an abnormal display, and do not touch the TAB.

10. Do not disassemble the LCD module.

11, NC feet should be suspended, do not pick up anything.

12. If the logic circuit is powered off, do not input a signal.

13. In order to prevent static damage of components, maintain a good working environment.


14, to avoid open circuit, be careful of the operation of heat sealing paper.

15. The edge of the glass screen is sharp and careful.


Second, storage considerations

1. When storing the LCD module, avoid direct exposure to sunlight or fluorescent light. Store the LCD module in an anti-static bag and store it at room temperature under normal humidity. (Avoid high humidity/high temperature and low temperature below 0 °C.) If possible, the LCD module should be stored under the conditions when it is shipped from our company.

   a. When you move the module, don't fall to the ground.

   b. The assembled tools, such as soldering irons, must be properly grounded.

   c. In order to reduce the generation of static electricity, do not perform assembly and other work in a dry environment.

   d. The LCD module has a film that protects the display. Be careful when tearing off this protective film as static electricity may be generated.

2. Minimize electrode corrosion. Water droplets, moisture condensation, or currents in high temperature environments can accelerate electrode corrosion.

Third, other


1. At low temperatures (below the storage temperature range), liquid crystal solidification can cause directional defects or bubbles (black or white). Air bubbles are also generated when the liquid crystal module is subjected to strong vibration at a low temperature.


2. If the LCD module works for a long time and displays the same pattern, the pattern will remain on the screen like a phantom and there will be subtle contrast differences. If you want to regain normal working status, you can temporarily stop using it for a while. It is worth noting that this phenomenon does not adversely affect the reliability of performance.