如何检查屏幕上的坏点

You just bought a new monitor and noticed a tiny bright dot that won't go away. Or a faint black spot in the middle of your laptop screen. That's a pixel defect. This guide explains the three types of pixel defects, how to test for them, and which ones you can actually fix.

Dead vs Stuck vs Hot Pixels

Three different defects, each looking different against different backgrounds:

Dead pixel: permanently off, appears black on any background. The transistor controlling that pixel has failed. Cannot be repaired.

Stuck pixel: permanently on in one sub-pixel (red, green, or blue). Appears as a bright dot of that color on a black background, and invisible on a matching color background. Sometimes repairable.

Hot pixel: all three sub-pixels stuck on, appears bright white. Rarer than stuck pixels. Sometimes repairable.

How to Test for Dead Pixels

Open our free Dead Pixel Test and cycle through solid colors fullscreen. On a clean screen, every pixel should be the same color. Any pixel that's a different color is faulty.

Run the test in a dark room with the screen at maximum brightness. Sit 12–18 inches from the display. Inspect carefully: small defects are easy to miss without the contrast that solid colors provide.

Can You Fix a Dead Pixel?

Dead pixels are unrecoverable. The transistor is broken at the silicon level. No software, technique, or repair tool can bring it back.

Stuck pixels are sometimes recoverable using rapid color cycling. The theory: rapidly switching colors over the stuck pixel may overwhelm the stuck sub-pixel's transistor and free it. Success rates vary widely: some report 30–50% success.

Stuck Pixel Fixer

Our Stuck Pixel Fixer rapidly flashes RGB colors in a draggable box. Position the box over the stuck pixel and leave it running for 10–30 minutes. Some users report success only after multiple hour-long sessions over several days.

An older trick: gently apply pressure with a soft cloth over the stuck pixel while the colors are flashing. Use minimal pressure: too much will damage the LCD permanently. Skip pressure entirely on OLED phone screens, which are more delicate.

When to Claim Warranty

Manufacturers warranty against more than a threshold number of dead pixels: typically 3–5 for monitors and laptops. Apple, Dell, HP, Lenovo, ASUS each publish their own policies. Run the dead pixel test within the return window and photograph any defects.

Some retailers offer "zero dead pixel" guarantees for an additional fee. For high-end displays where a single defect would bother you, this is worth considering.

Prevention Tips

You can't prevent random pixel failures, but you can extend display lifespan. Avoid leaving static images on OLED screens for long periods (causes burn-in, which looks similar to stuck pixels). Keep the display cool: heat accelerates pixel degradation. Don't press hard on LCD screens or store laptops with the lid pressing against objects.