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LCM LCD Module Product Inspection Standards and Methods

Time : 2021-11-25 15:56:39 Popularity : 108

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1. Inspection standards for LCM LCD module products:

(1) Test conditions:

(1) The environmental conditions are (normal temperature) 20~25 degrees C (normal temperature) 65%+5% RH (humidity).

(2) Inspection lighting tools are 20W fluorescent lamp, 50 cm above the work surface (product) and 30 cm above the visual distance.

(2) Inspection criteria:

The test is mainly based on batch sampling, and the sampling standard is based on GB2828-93.

2. Common terms used in LCM module testing:

(1) Black points and lines

(1) Dark spots and dark linear spots are displayed when the power is on, and there is no significant change when the LCD drive voltage changes.

(2) Darker linear spots appear when the power is on, and large changes occur when the LCD drive voltage changes.

(2) White spots

(1) Light-colored spots are shown when the power is on, and there is no big change when the LCD drive voltage changes.

(2) Light-colored spots are displayed when the power is on, and large changes occur when the LCD drive voltage changes.

(3) White line

(1) Light-colored linear spots are displayed when the power is on, and there is no significant change when the LCD drive voltage changes.

(2) Light-colored linear spots are displayed when the power is on, and large changes occur when the LCD drive voltage changes.

(4) Blue spots

When the power is on, very dark spots appear, and the LCD drive changes greatly.

(5) Vertical line (vertical line) defect

When power is on, the longitudinal (usually short axis) line is not bright and light.

(6) Horizontal line defect

When the power is on, the horizontal (usually major) lines are not bright and light.

(7) Cross-line defect

When the power is on, the intersection of the horizontal and vertical lines is not bright.

3. Scope of inspection:

(1) General appearance inspection:

(1) All the dimensions of the LCM LCD module (each device).

(2) Polarizer appearance and color uniformity of LCD of LCM liquid crystal module. Polarizer appearance includes scratches, creases, bubbles and dirt.

(3) Leakage, virtual welding, insufficient solder, bridging and overflow of solder and solder joints.

(4) The appearance of LCM LCD module housing, whether the electroplating paint is even, whether there are scratches and paint stripping.

The uniformity and scratches of the lead between the components.

_Whether the resistance film on the PCB board is peeling off (with size limitation) or whether the copper foil of the line is scratched.

The tightness of screw and shell foot.

(2) Power-on display check:

1. Input voltage, operating frequency, consumption current, contrast of LCD and response speed.

(2) When the power is on (according to standard input voltage), its viewing angle range, whether the graphics have the above defects, and whether the graphics are out of alignment.

4. LCM LCD module sampling environment test:

Sampling of various environmental tests before LCM LCD modules leave the factory includes:

(1) High temperature charging, high temperature (40, 60 C) placement test.

(2) Low voltage charging and low temperature (0 or -20 C) placement test.

(3) Place at high temperature and humidity with electricity.

(4) Vibration test.

The above temperature and test are controlled within a certain period.

5. LCM LCD module product inspection methods:

LCM LCD module product inspection is divided into several situations. There are exemption from inspection, full inspection and sampling inspection according to the quantity of inspection. There are self-inspection, mutual inspection and special inspection according to the inspection methods. According to the means of inspection, there are rational test and sensory test.

(1) Sensory examination:

Sensory inspection of LCM LCD module, that is, visual inspection of LCM LCD module housing, scratches, electroplating shedding; Are there any scratches and bubbles on the surface of LCD screen? Whether the components and screws on the PCB board are defective (including lead); Visual items also include: solder spot, whether or not the resistance film falls off, and the color of the LCD screen.

(2) Physical and chemical tests:

The physical and chemical properties of LCM liquid crystal modules are measured by mechanical, electronic or chemical tools. For example:

(1) Detect the length of scratches, the number and size of bubbles on the polarizer of LCD screen with a cursor caliper and a magnifying glass. There are certain number and size limitations in the defect judgment criteria.

(2) Using a magnifying glass, the solder joints on PCB board of LCM LCD module can also be checked: whether there is leakage, virtual welding, insufficient solder, overflow of solder, bridging, etc.

(3) Examine with a microscope: PCB board graphics (gold-plated layer), whether the line has direction defect, connection, short circuit, break.

(4) Testing the performance of LCM LCD module appliances with self-made testing tools according to the test instructions of special standard files. For example:

Display the power-on check, detect the LCD screen, under the standard input voltage, its viewing angle range, display graphics, color depth conform to the test standards, show whether there are black, white, white lines in the area.


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Title:LCM LCD Module Product Inspection Standards and Methods
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