LCD Display Usage Precautions
- Jul 18, 2018 -

         

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The LCD display should prevent the application of a DC voltage: the smaller the DC component of the drive voltage, the better. 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.

    The LCD display should be protected from UV radiation: avoid direct sunlight for long periods of time. The liquid crystal and the polarizing plate are organic substances, and photochemical reaction and deterioration occur under ultraviolet irradiation. Therefore, in the assembly of the liquid crystal display device, it is necessary to consider whether or not it is necessary to provide an ultraviolet shielding filter or other ultraviolet shielding method in front of the liquid crystal display device depending on its use and environment.

    The LCD display should be protected from harmful gases: liquid crystals and polarizers are organic, chemical reactions and deterioration occur in the environment of harmful gases, so use isolation measures that should take harmful gases, and do not carry out after the machine is assembled. Sealed and stored for a long time to prevent the concentration of chemical gases generated by the plastic case and the circuit board cleaning agent from damaging the liquid crystal and the polarizer.

    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.

    The liquid crystal state disappears beyond a certain temperature range, so it must be stored and used within the specified temperature range. When the temperature is too high, the liquid crystal state disappears and becomes liquid, and the display surface is black, which cannot work. Please be careful not to energize at this time, and the self-recovery can be resumed after the temperature is lowered. 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.

    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.

    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%.

    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, only use isopropyl alcohol (glycerol), alcohol, freon, and never use acetone, aromatic solvents, such as toluene, etc., otherwise the polarizer on the surface of the device will be damaged.

    The liquid crystal display device is driven by the COMS circuit, so it is also necessary to pay attention to the fact that the input module cannot be added when the display module is not powered. It is necessary to prevent static electricity during assembly, wear anti-static overalls, ground the human body, work table and soldering iron, tools, etc. should be grounded.

    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 80 °C. Do not wash with detergent at the pin, because the detergent will decompose chlorine in sunlight and form hydrochloric acid after absorbing water, thus corroding the electrode.