TFT LCD Image Retention or Ghosting: An Overview

Definition:

TFT LCD Image Retention or Ghosting is a common phenomenon in Thin-Film Transistor Liquid Crystal Displays (TFT LCDs), where an image continues to be faintly visible on the screen even after a new image has replaced it. This issue, also known as “ghosting” or “image retention,” arises when certain pixels in the LCD do not immediately revert to their inactive state. Consequently, the previous image’s faint outline, or “ghost,” persists on the display.

Primary Causes and Contributing Factors:

1. Pixel Response Time
   • Main Factor: Slow response time of liquid crystals is the primary cause of ghosting. Delayed pixel transitions between states result in the previous image lingering, creating a ghosting effect.
2. Prolonged Display of Static Images
   • Impact on Pixels: Continuously displaying static or high-contrast images for extended durations can render some pixels less responsive to change, intensifying ghosting.
3. Temperature Effects
   • Sensitivity to Temperature: Liquid crystals’ reaction to extreme temperatures can slow down their response time, thus elevating the ghosting likelihood.
4. Quality of the Display
   • Display Efficiency: Inferior quality TFT LCDs, including older models, might show more ghosting due to less effective liquid crystal materials or substandard electronic components.
5. Age of the Display
   • Degradation Over Time: The liquid crystals in TFT LCDs can deteriorate with age, resulting in slower response times and heightened ghosting.
6. Compatibility of the AD Driver Board
   • Driver Board Match: Ghosting can be related to the compatibility between the AD driver board and the LCD screen. Incompatibility in driving voltages between the motherboard and the LCD screen’s design can contribute to ghosting.

Avoid Ghosting in TFT LCDs:

To avoid the ghosting phenomenon on LCD screens, the following measures can be taken:

1. Use Screen Savers: Allow the pixels of the LCD screen to display different content, avoiding static images for more than 20 minutes.
2. Regular Screen Cleaning: Create a completely white image and move it around the screen for several hours without turning on the backlight.
3. Turn Off Backlight: Further extend the lifespan of the backlight LEDs.
4. Power Off Sleep Mode: Let the LCD screen go into sleep mode when not in use to avoid any unnecessary driving.

These measures help reduce the occurrence of ghosting on LCD screens. Additionally, adjusting the motherboard’s voltage to match the LCD screen is also an important step in avoiding ghosting.