What Causes Dead Pixels and Can You Prevent Them?
Understanding the science behind pixel defects, what makes them happen, and what you can realistically do about them.
Understanding the science behind pixel defects, what makes them happen, and what you can realistically do about them.
Last updated: February 2026
To understand what causes a pixel to die, you first need to understand what a pixel is and how it operates. In an LCD (liquid crystal display), a single pixel is actually composed of three sub-pixels: one red, one green, and one blue. Each sub-pixel consists of a thin-film transistor (TFT), a layer of liquid crystal material, and color filters sandwiched between two glass substrates with polarizers on each side.
The TFT acts as a tiny electrical switch. When a voltage is applied to the transistor, it creates an electric field across the liquid crystal layer, causing the rod-shaped liquid crystal molecules to rotate. This rotation changes how much light from the backlight passes through the sub-pixel. When the crystals are fully aligned with the polarizers, maximum light passes through (the sub-pixel appears bright). When they are perpendicular, the light is blocked (the sub-pixel appears dark). By varying the voltage across each of the three sub-pixels independently, the pixel can produce a wide range of colors.
A 4K display contains 3840 × 2160 = 8,294,400 pixels, which means 24,883,200 individual sub-pixels, each with its own transistor. The fact that the vast majority of these transistors function flawlessly for years is a remarkable manufacturing achievement. But with that many components, the occasional failure is statistically inevitable.
OLED (organic light-emitting diode) displays work on a fundamentally different principle. Each sub-pixel is a self-emissive element: it contains organic compounds that emit light when electrical current passes through them. There is no backlight and no liquid crystal layer. The organic material is deposited in extremely thin layers (measured in nanometers) between an anode and cathode. When current flows, electrons and holes recombine in the organic layer, releasing energy as photons.
The composition of the organic material determines the color of light emitted. In most OLED displays, each pixel contains red, green, and blue OLED sub-pixels (or in Samsung's implementation, a PenTile arrangement with red, green, green, blue). Because each sub-pixel generates its own light, an OLED pixel that fails simply stops emitting, appearing as a permanent black spot against lit neighbors, which makes it more noticeable than a dead pixel on an LCD where the backlight provides some ambient glow even through a failed pixel.
People often use “dead pixel” as a catch-all term, but there are actually distinct types of pixel defects, and the distinction matters because it affects whether the defect is fixable. You can check your display for both types using the DisplayPixels pixel test tool, which cycles through solid colors to make defective pixels easy to spot.
A truly dead pixel is one where the transistor has permanently failed. In an LCD, this means the transistor can no longer apply voltage to the liquid crystal layer. Depending on the panel type, the default (undriven) state of the liquid crystals may be either transparent or opaque. On a normally-black panel (most modern IPS and VA panels), a dead pixel appears as a permanently dark spot. On an older normally-white panel (some TN displays), a dead pixel might appear as a permanently bright spot. On an OLED display, a dead pixel is always dark because the organic material requires current to emit light. Dead pixels are almost always permanent; the transistor failure is irreversible without physically replacing the pixel, which is not feasible.
A stuck pixel is one where a sub-pixel is locked in a permanently on state, displaying a constant color regardless of the signal it receives. This typically occurs because the transistor is stuck in a partially or fully conducting state, keeping the liquid crystal layer (or OLED emitter) permanently active. Stuck pixels appear as a bright dot of a specific color: always red, always green, always blue, or a combination like cyan, magenta, or yellow if multiple sub-pixels are stuck. Stuck pixels are sometimes fixable because the transistor has not permanently failed; it is just stuck in one position and may respond to pixel-exercising techniques. For methods to attempt fixing stuck pixels, see our guide to fixing stuck and dead pixels.
Sometimes only one of the three sub-pixels fails while the other two continue working. The pixel can still display colors, but with a reduced range. For example, if the blue sub-pixel dies, the pixel can display combinations of red and green (producing yellows, oranges, and so on) but cannot produce blue, cyan, magenta, or white accurately. These partial defects are less noticeable in normal viewing because the pixel still contributes to the image, just with slightly inaccurate color in that one-pixel location.
The most common cause of dead pixels, especially those present from the moment you unbox a new display, is a manufacturing defect in the thin-film transistor layer. TFTs are fabricated using photolithography processes similar to semiconductor manufacturing, but on much larger substrates (glass sheets that can measure several meters across). Any microscopic particle of dust, a slight impurity in the deposition chemicals, or a minor misalignment during lithography can render an individual transistor non-functional. Given that a single 4K panel contains nearly 25 million transistors, achieving a 99.999% yield still means multiple potential defects per panel. Manufacturers sort panels by defect count: panels with zero defects go to premium product lines, panels with a few defects go to standard consumer products, and panels with many defects are rejected or downgraded.
Applying pressure to an LCD screen can permanently damage the liquid crystal alignment layer, the TFT, or the color filter. This is why you should never poke an LCD screen with a sharp object or press hard against it. Even moderate, sustained pressure (such as stacking heavy items on a closed laptop) can create clusters of dead or stuck pixels. On OLED displays, pressure can damage the extremely thin organic layers, causing localized failure. The damage may not appear immediately; micro-fractures in the substrate can propagate over time, eventually causing pixel failure days or weeks after the initial pressure event.
Power surges, static discharge, and voltage irregularities can destroy individual transistors. This is more common in environments with unstable power or during electrical storms, though modern display electronics include protection circuitry. In rare cases, a defect in the display's driver IC (the chip that distributes signals to rows and columns of pixels) can cause entire rows or columns of pixels to fail simultaneously, which is a more dramatic and distinct issue from individual dead pixels.
Extreme temperatures can cause dead pixels. LCD panels are sensitive to freezing conditions because the liquid crystal material can undergo phase transitions at very low temperatures, potentially damaging the alignment layer when it re-liquefies. High temperatures accelerate the degradation of organic materials in OLED displays and can cause delamination of the various thin-film layers in both LCD and OLED panels. Repeated rapid temperature changes (thermal cycling) can create mechanical stress at the microscopic junctions between different materials in the pixel structure, leading to fatigue failure over time.
All displays degrade over time. In LCDs, the backlight gradually loses brightness and may shift in color temperature, but the pixel layer itself is relatively stable over many years. Individual TFTs may fail as electromigration (the gradual movement of metal atoms within the transistor's conductors due to electron flow) eventually breaks a critical connection. This process takes years and is why older monitors sometimes develop a few dead pixels that were not present when new. In OLED displays, the organic emitters degrade with use, and blue OLED materials degrade faster than red or green due to the higher energy required to produce blue light. While this degradation primarily manifests as reduced brightness rather than dead pixels, advanced degradation can eventually cause individual sub-pixels to fail entirely.
The International Organization for Standardization defines pixel defect tolerance classes in ISO 9241-302 (formerly ISO 13406-2). This standard categorizes pixel defects into three types and assigns four quality classes:
| Class | Type 1 (Bright) | Type 2 (Dark) | Type 3 (Sub-pixel) |
|---|---|---|---|
| Class 0 | 0 | 0 | 0 |
| Class 1 | 1 | 1 | 2 |
| Class 2 | 2 | 2 | 5 |
| Class 3 | 5 | 15 | 50 |
These numbers represent the maximum allowed defects per million pixels. For a 4K panel with approximately 8.3 million pixels, Class 1 allows up to about 8 bright defects and 8 dark defects. Most reputable monitor manufacturers target Class 1 or better. Some premium brands offer zero-bright-pixel guarantees, meaning they will replace any panel with even one bright defect, though dark defects may still be allowed under their warranty terms.
When purchasing a new monitor, check the manufacturer's specific dead pixel policy. It may be more generous than the ISO class they officially target. Some retailers also offer their own pixel-perfect guarantees for an additional fee, which can be worthwhile if pixel defects would be particularly bothersome for your use case (such as photo editing on a solid-color background).
While you cannot prevent manufacturing defects or the inevitable effects of aging, you can take steps to minimize the risk of premature pixel failure.
Never touch, poke, or press directly on an LCD or OLED screen. When cleaning, use a soft microfiber cloth with gentle, even pressure. Avoid using paper towels or household cleaning products, as they can scratch coatings and create pressure points. When transporting a laptop, make sure nothing heavy is pressing against the closed lid, and use a padded sleeve or case.
Keep your display in a climate-controlled environment. Avoid placing monitors near heating vents, in direct sunlight, or in unheated spaces where temperatures drop below freezing. If a display has been in a cold environment (such as during shipping in winter), allow it to acclimate to room temperature for several hours before powering it on. The moisture condensation that can form on cold electronics when brought into a warm room can cause electrical shorts in sensitive components.
Connect your monitor through a quality surge protector or UPS (uninterruptible power supply). This protects the display's electronics from voltage spikes that can damage transistors and driver circuits. Avoid plugging your monitor into extension cords of questionable quality or outlets known to have electrical issues.
While this is primarily an OLED concern (see the burn-in section below), even LCD pixels can develop persistence issues if the same static image is displayed continuously for very long periods. Use a screensaver or set your display to turn off after a reasonable idle period. Vary your displayed content and avoid leaving static toolbars, taskbars, or watermarks visible at the same position for months on end.
Higher-quality panels from established manufacturers undergo more rigorous quality control and use better materials. While dead pixels can occur on any display, the probability is lower on panels from manufacturers with strict QC processes. Monitors from brands like EIZO, Dell, BenQ, and LG in their professional lines typically have lower defect rates and better dead pixel warranties than the cheapest available options.
OLED burn-in is sometimes confused with dead pixels, but they are fundamentally different phenomena. Burn-in occurs when the organic emitting materials in certain pixels degrade unevenly due to prolonged display of static content. The affected pixels do not die; they continue to function but emit less light than surrounding pixels, creating a faint “ghost image” of the static content that was displayed.
The mechanism behind burn-in is cumulative electroluminescence degradation. Every time an OLED pixel emits light, a tiny fraction of the organic molecules in the emitting layer undergo irreversible chemical changes. Over thousands of hours, this degradation measurably reduces the pixel's light output. If certain pixels are driven harder than others (because they are constantly displaying a bright UI element like a white taskbar or a channel logo), they degrade faster, creating a visible brightness differential.
Blue OLED sub-pixels are most susceptible because blue light requires higher-energy photon emission, which causes faster degradation of the organic material. This is why OLED manufacturers use various mitigation strategies: pixel shifting (subtly moving the image by one or two pixels periodically), brightness limiting on static content detection, and periodic pixel refresh cycles that attempt to even out degradation across the panel.
In severe cases, burn-in can progress to the point where affected sub-pixels produce noticeably wrong colors or fail to emit light at the expected intensity even for dynamic content. At this extreme stage, burn-in starts to resemble partial sub-pixel defects. However, unlike sudden dead pixels caused by transistor failure, burn-in is always a gradual process that develops over months or years of specific usage patterns.
The practical advice for OLED users is to use your display normally without anxiety. Modern OLED panels are far more resistant to burn-in than earlier generations. Use the built-in panel-care features, avoid leaving static high-contrast elements on screen when you walk away, and enjoy the superior contrast and color that OLED provides. For a quick check on your display's sub-pixel health, the DisplayPixels pixel test can cycle through solid colors that make any uneven degradation visible.
If you discover a dead pixel on a new monitor, your first step should be to check the manufacturer's dead pixel policy. Some companies will replace the entire panel for a single bright defect but require multiple dark defects before authorizing a replacement. Others offer zero-defect warranties on their premium lines but have more lenient policies on budget models.
Document the defect by photographing it against both a white and black background, and note its position on the screen. If the retailer has a return window (most offer 14–30 days), returning the monitor for a replacement is often easier than going through the manufacturer's warranty process. Be aware that a replacement panel may also have a dead pixel; this is the “panel lottery” reality of display manufacturing. Buying from a retailer with a generous return policy gives you the best chance of ending up with a defect-free panel.
If a dead pixel develops after the initial return window but within the warranty period, contact the manufacturer directly. Provide your serial number, proof of purchase, and documentation of the defect. Most manufacturers handle warranty claims by shipping a replacement unit and providing a return label for the defective one.
A dead pixel receives no electrical signal and appears permanently black (on LCD) or unlit (on OLED). A stuck pixel is locked in an always-on state, displaying a constant color like red, green, or blue. The key difference is that stuck pixels are often fixable using pixel-exercising software or gentle pressure techniques, while truly dead pixels are usually permanent because the underlying transistor has failed.
Dead pixels do not physically spread like a disease. Each pixel has its own independent transistor, and the failure of one does not directly cause adjacent pixels to fail. However, if the root cause is physical damage (such as a crack in the substrate or pressure damage), the affected area may include multiple pixels, and the damage zone might appear to grow over time as stress propagates through the glass.
Under the ISO 9241-302 standard, the acceptability depends on the defect class. Class 0 (the highest quality) allows zero defects. Class 1 allows up to 1 bright and 1 dark defective pixel per million pixels. Most consumer monitors are manufactured to Class 1 or Class 2 standards. Many manufacturers have their own zero-dead-pixel warranties, especially on professional and gaming displays. Check the specific warranty terms before purchasing.
A screen protector can help prevent dead pixels caused by physical impact or pressure damage by distributing force across a larger area rather than concentrating it on individual pixels. However, it cannot prevent dead pixels caused by manufacturing defects, electrical failure, or age-related degradation, which account for the majority of dead pixel occurrences. A protector is most useful for portable devices like laptops and phones that are subject to physical contact.
No. OLED burn-in is uneven degradation of the organic compounds in certain pixels, causing them to emit less light or slightly different colors compared to surrounding pixels. The affected pixels still work but have reduced output. Dead pixels, by contrast, have completely failed and produce no light at all. Burn-in is gradual and affects areas that displayed static content for extended periods, while dead pixels typically appear suddenly due to transistor failure.