TFT displays do not generate light themselves – they utilize an LED backlight, which is controlled by liquid crystals to allow or block light.
For complete “black,” the crystals in IPS-technology TFTs should entirely block the light. If they fail to do so, for instance due to internal display stresses, this phenomenon is referred to as backlight bleeding.
Typical Symptoms
- Bright spots or glowing corners on a black image
- Typically more visible in dark environments.
- Often appears in the upper or lower corners, but can also occur laterally.
Causes of Backlight Bleeding
| Housing Pressure / Panel Tension | If the display is overtightened or under tension, it can deform the crystal structure, allowing light to pass through. |
| Assembly Tolerances / Manufacturing Defects | A panel that is not perfectly flat or uneven bonding. Ultra-thin designs can lead to larger gap dimensions. |
| Non-uniform Backlight | The backlight is not perfectly distributed or diffused. |
| IPS Technology | While IPS offers excellent viewing angles and color reproduction, it is prone to bleeding (compared to TN). |
