LCD module assembly and problems to be aware of when using

The liquid crystal module is a component that assembles the liquid crystal device and the LCD controller, the driving circuit, and the circuit board PCB. He can connect directly to the computer. When using this kind of module, in addition to the precautions when using the general LCD screen, you should also pay attention to the following items during assembly and use:

1. Handle the protective film

A protective film is placed on the surface of the finished liquid crystal module to prevent contamination of the surface during assembly. It cannot be removed before the end of the entire machine assembly to avoid soiling or staining the display surface.

2. Add padding

Preferably, a pad of about 0.1 MM is added between the module and the front panel. The panel should also remain absolutely flat. Make sure that no distortion is produced after assembly. And improve the performance of earthquake resistance.

3. Strictly prevent static electricity

The control and drive circuit in the liquid crystal display module is a micro-power, low-voltage CMOS circuit, which is easily broken down by static electricity, and the human body sometimes generates high-voltage static electricity of up to several volts or hundreds of volts. We must be very careful in handling, assembly and use, to prevent static electricity. to this end:

 

1) Never touch the outer leads, the circuit on the board, and the metal frame with your hands.

2) If it is necessary to directly contact, the human body and the module should be kept at the same potential, or the human body should be well connected to the ground.

3) The soldering iron used in soldering must be well grounded to ensure that it does not leak.

4) Some operating electric cones and other tools must be well grounded to ensure that they are not leaking.

5) Do not use a vacuum cleaner for cleaning. Because the vacuum cleaner can generate a lot of static electricity.

6) When the air is relatively dry, static electricity may also be generated. Therefore, the humidity in the workplace should be above RH60%.

7) Ground, chairs, carts, work benches, shelves, and tool rooms should all form a resistive contact to maintain the same potential, otherwise static electricity may be generated.

8) When taking out or putting it back in the bag or moving the position, you should also be extra careful not to generate static electricity. Do not arbitrarily change or discard the original packaging.

9) Electrostatic breakdown It is a kind of damage that cannot be repaired. Be sure to pay extra attention and not care.

 

4. Some precautions during assembly operations.

The modules are carefully designed and assembled, so please do not process and trim them.

1) Metal frame claws must not be twisted and disassembled at will.

2) Do not arbitrarily modify the shape, wiring, assembly holes and components of the processed PCB.

3) It is not possible to modify the conductive strip.

4) Please do not modify any internal brackets.

5) Do not touch, drop, bend, or twist the module.

5. Welding

When soldering the external connection and interface circuit of the module, the following procedures should be followed.

1) The temperature of the tip should be less than 280 ° C

2) Welding time must be less than 3-4 hours

3) Welded material: eutectic, low melting point.

4) Do not use acid flux.

5) Repeat the welding as much as possible not more than three times, and each repetition needs to be separated by 5 minutes.

6. Module use and maintenance

1) When the module is connected to the power supply and disconnected from the power supply, it must be performed according to the timing of the diagram. That is: it must be input at the positive power supply (5±0.25V) before the signal voltage can be input. If the signal voltage is input before the power supply is stably connected or after being disconnected, the integrated circuit in the module will be damaged and the module will be damaged.

Power supply 4.75V 4.75V

a, power-on sequence b, power-down sequence

2) The dot matrix module is a high-resolution liquid crystal display, which has a great relationship with display contrast, viewing angle, temperature and driving voltage. Therefore, Vee should be adjusted to the best contrast and viewing angle. If the Vee is set too high, it will not only affect the display, but also affect the life of the display device.

3) When used at the lower limit of the specified operating temperature range, the display response will be slow. When the upper limit of the specified operating temperature range is used, the entire display interface will turn black directly. This is not damage. After the temperature range is restored, it can be restored.

4) Pressing the displayed part hard will produce an abnormal display. As long as we cut off the power and reconnect it, it can be restored.

5) When the surface of the LCD screen or module is fogging, do not go to the power supply, because this will react to the electrode chemistry and produce a broken wire.

6) If it is used for a long time in the sun and under strong light, it may produce a residual image.

7. Storage of liquid crystal module

If you store for a long time (such as several years), we can recommend the following ways.

1) Insert into a polyethylene bag (preferably with an antistatic coating) and seal the mouth.

2) Store between -10 °C and +35 °C.

3) Put it in the dark to avoid glare.

4) It is absolutely impossible to press any item on the surface.

5) Strictly avoid storage under extreme temperature/humidity conditions. It must be stored under special conditions. It can also be stored at 40 ° C, 85% RH, or 60 ° C, less than 60% RH, but should not exceed 168 hours.

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