The residual image of TFT LCD screen is also known as "burning screen". In a cathode ray tube display, this will cause phosphorus wear and the pattern will be burned into the display. But when used on LCD screens, it does not involve actual heating or combustion. How would you solve the problem of residual shadows when using a TFT LCD screen?
The residual image is a noticeable residue from the previous image, which some technicians may describe as a "screen burn". It is the result of continuously driving a certain point and other points for a long time. How is the residual shadow generated?
Liquid crystal (LC) in TFT is a polar crystalline material that can undergo corresponding distortion due to an electric field.
The liquid crystal in thin film transistors must be driven by alternating current. If DC drive is used, the polarity of the crystal will be disrupted.
When continuously driving TFT pixels, the associated slight imbalance will attract free ions to the internal electrode, and the ions adsorbed on the internal electrode will cause a driving effect similar to DC+AC.
Repair method for TFT LCD screen:
The content is fixed for a short period of time without any residual images. If there is residual shadow, the thin film transistor display screen can be repaired as follows:
Shutting down TFT will give you a chance to recover within a few hours. (May take 48 hours)
Create an all white image and move it on the screen for a few hours without turning on the backlight.
There are many shadow repair software available online, which may also be helpful. After the appearance of residual shadows, it will be easier to reproduce, and preventive measures need to be taken to prevent the reproduction of TFT LCD residual shadows.
Screen saver, which allows TFT pixels to display different content when the system is not running, such as displaying mobile screensavers or switching content irregularly, to avoid displaying static images for more than 20 minutes;
Turn off the backlight to further extend the lifespan of the backlight LED;
Signal: After power on, the display scanning signal should be continuously provided to avoid scanning pauses causing TFT drive;
TFT LCD screen residual test standard
Test (example):
Normal temperature; Black and white checkerboard display (approximately 60x60 pixels per grid); Static display for 30 minutes.
Full screen display 128 (50%) gray; After waiting for 10 seconds, no residue can be considered qualified.
How does a black and white chessboard produce a testing effect?
For a normal white thin film transistor, the white area receives the minimum driving voltage, while the black area receives the maximum driving voltage. Therefore, free ions inside the thin film transistor can be easily attracted to the black area. (Areas with high driving voltage)
When the entire screen becomes 128 (50%) grayscale, the same driving voltage will be used for the entire screen, and ions will leave the previously attracted position in a short period of time;
In addition, when the full screen 128 (50%) is gray, it is easier to detect abnormal display.