How to determine if the LCD screen is damaged due to high temperature?
Date:2026-05-28
How to determine whether the LCD screen is damaged due to high temperature can be observed from three aspects: appearance, display performance, and touch. High temperatures often cause denaturation of liquid crystal materials, aging of polarizing films, or failure of adhesive layers. The following are specific inspection methods:
1. Appearance inspection (most intuitive)
Yellowing/browning of edges or corners: Yellow or brown patches resembling burnt spots appear on the edges of the screen, commonly found in direct sunlight or high-temperature enclosed environments (such as the dashboard in a car).
Screen bubbling or delamination: Irregular bubbles or separation between the surface glass/plastic and the internal liquid crystal layer indicate that the adhesive has melted or vaporized due to high temperature.
Edge leakage (black spots): Irregular black spots appear in the corners of the screen, shaped like ink seeping open, and may expand with pressure or time - high temperatures cause the liquid crystal material to expand and the seal to fail.
Surface cracks or fine lines: The screen is not impacted by external forces, but there are spider like fine cracks on the surface, which may be caused by uneven thermal expansion and contraction of the plastic substrate or polarizer due to high temperature.
2. Display performance test
Image Retention:
Display high contrast still images (such as black and white checkerboards) for 5-10 minutes, then switch to a pure gray background.
If the contour of the previous image is still faintly visible and does not fade for a long time, it indicates that high temperature has accelerated the aging of liquid crystal molecules or organic materials.
Severe response tailing:
When quickly dragging windows or playing dynamic videos, the edges of objects leave obvious colored or dark trailing, which is much more severe than normal use.
Contrast or color abnormality:
The overall image appears white or gray, with impure black (presenting a grayish purple color), or local colors noticeably yellowish/reddish. High temperature may damage the distortion angle of the liquid crystal or the color filter film.
Dark or bright spots:
Some areas of the screen are noticeably darker than the surrounding area (like being smoked), or irregular bright areas appear, often accompanied by abnormal temperature (can be lightly touched with the back of the hand, this area may be hotter).
3. Physical and environmental verification
Touch temperature: The screen will feel hot to the touch (over about 60 ℃) for a period of time before the above symptoms appear. Short term high temperatures (such as 10 minutes outdoors in summer) generally do not cause immediate damage, but long-term or repeated high temperatures accumulate damage.
Odor: Smelling burnt plastic or chemical odor (even if no smoke is emitted) indicates that the internal film or adhesive layer has thermally decomposed.
Usage scenario: Recall whether the device was placed in a car during summer, next to a heater, exposed to direct sunlight on a windowsill, or if the device's heat dissipation holes were blocked, resulting in internal heat accumulation.
Special attention
Distinguishing from physical impacts: The black spots affected by impacts are usually radial or have stress points at the center of cracks, while high-temperature black spots have blurred boundaries and no stress cracks.
Low pressure/high temperature composite fault: Some black spots may temporarily shrink after the temperature drops, but reappear after heating, indicating that the seal has been damaged and will eventually deteriorate.
Touch function: Some capacitive screens may experience touch drift or no response after high temperature (due to changes in ITO layer resistance).
Urgent handling and conclusion
If it is confirmed that the damage is caused by high temperature and cannot be repaired on its own, the only option is to replace the screen. Continuing to use may exacerbate damage or cause a short circuit.
Mild yellowing may sometimes partially recover after cooling, but long-term reliability decreases.
Prevention: Avoid working or storing equipment in environments above 50 ℃ for extended periods of time, especially in vehicles or near kitchen equipment during summer.
If black liquid seeps out or smoke appears on the screen, immediately turn off the power and stay away from flammable materials - this indicates that the LCD box has ruptured and there may be a small amount of irritating gas (although not highly toxic, ventilation is required).
If you are unsure whether it is due to high temperature or other aging (such as prolonged use of screen burn-in), you can compare it with normal equipment of the same model, or observe it again after being placed in a cold state (25 ℃) for 2 hours. High temperature damage usually does not completely disappear due to cooling.
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