How to troubleshoot and resolve 90% of TFT screen malfunctions?

I. Signal/Driver-Related Abnormalities (White Screen/Distorted Screen/Flickering Screen) Abnormal Phenomena: White screen, black screen, distorted screen, vertical lines, horizontal lines, flickering, ghosting. Causes:

1. Poor contact of the FPC cable. Never plug or unplug the screen while it's hot, as this can easily cause "screen burn-in."

2. Abnormal IC or FPC bonding, indicating a functional malfunction.

3. Unstable current and voltage.

4. Abnormal timing or power supply parameter settings on the motherboard, which can cause ghosting, especially with MIPI screens, often resulting in backlight being on but the screen not lighting up.

5. EMI electromagnetic interference. Excessive interference can cause flickering, and in severe cases, black or white screens.

Solutions:

Re-plug the screen cable and check for foreign objects. Always disconnect the power first.

Cross-verify by replacing the screen or motherboard to see if the phenomenon recurs.

Check if the screen current and voltage are normal, and check for damage to the IC or LCD screen ITO area. Damage and Scratches

Check if the motherboard screen parameter settings are correct, adjust timing parameter settings. For MIPI screens, confirm if the initialization code is correct and successfully distributed. With 15 years of technical experience and strong technical support from the original manufacturer, we at Fanuo can assist in resolving screen anomalies.

Close interference sources and verify if there are any anomalies. Anti-interference measures need to be implemented according to the design.

II. Brightness and Optical Anomalies (Brightness/Color/Contrast):

Abnormal Phenomena: Insufficient brightness, uneven brightness, light leakage, color cast (blue/red), whitening, graying, abnormal grayscale, local color blocks

Causes:
1. Incorrect backlight drive current parameter settings; setting it too high or too low will cause excessively high or low brightness.
2. Backlight LED aging and light decay; prolonged use. The lifespan of a typical display screen is 15,000 hours, after which varying degrees of degradation will occur.
3. Light guide plate and diffuser sheet... Unevenness, improper assembly methods, or structural design can cause film arching, resulting in patches of black and bright light on the outside.

4. Poor optical bonding, such as OCA bubbles or abnormal debubbling, can cause reflection, making the display appear washed out.

5. Insufficient bonding precision or improper design of the light-shielding adhesive can lead to light leakage.

6. Improper selection of polarizers, LED beads, or film materials can cause color casts, resulting in excessive blue or red.

7. Incorrect Gamma or color temperature settings can cause abnormal contrast, manifesting as abnormal grayscale display.

Solutions:
1. Check the backlight power supply parameters to ensure they match requirements. Both voltage and current should be measured to adjust brightness to normal.

2. Consider the display's lifespan from the initial project stage. For example, our company, Fanno, can customize displays with a 50,000-hour lifespan.

3. Modify the design scheme and standardize the assembly process. Most film supply and light leakage anomalies are design issues.

4. Choose a reputable lamination manufacturer and clearly define acceptance standards.

III. Environmental & Reliability Anomalies:

Abnormal Phenomena: Low temperature failure to start/ghosting, high temperature black screen, yellowing, fogging

Causes: Each LCD has a specific operating temperature. Exceeding the temperature range will cause abnormal displays. UV rays, moisture, etc., can cause chemical reactions in the materials, aging, color shift, and poor waterproof and dustproof effects, leading to internal foreign objects or screen damage.

Solutions: Use wide-temperature LCDs. Standard operating temperature is -20°C to 70°C, with a wide temperature range of -30°C to 85°C. We at Fanuo can also customize -40°C operating displays. Replace with anti-UV materials. Using Fanuo's UV-blocking technology, it can block 99% of UV rays and intercept 86% of infrared rays, making the internal temperature of the display controllable. Choose waterproof materials during assembly.