Defective pixel

Defective Pixel

A defective pixel is a malfunctioning pixel on a digital display. These anomalies can manifest as a pixel that does not illuminate (a "dead pixel"), one that is always illuminated (a "stuck pixel"), or one that does not display the correct color output. Defective pixels are a common issue in various types of digital displays, including LCD (Liquid Crystal Display), OLED (Organic Light Emitting Diodes), and other display technologies. The presence of defective pixels can affect the quality and visual experience of the display.

Causes

Defective pixels can be caused by a variety of factors during the manufacturing process or throughout the lifespan of the display. During manufacturing, imperfections in the photolithographic process, contamination of the substrate, or errors in the alignment of the liquid crystal material can lead to defective pixels. After manufacturing, physical damage to the screen, excessive heat, or electrical failure can also result in pixel defects.

Types of Defective Pixels

• Dead Pixels: These pixels remain black when the screen displays an image. They fail to light up and are most noticeable against a white background.
• Stuck Pixels: Unlike dead pixels, stuck pixels are permanently "on". They typically show red, green, blue, or a combination of these colors, and are visible against any background.
• Hot Pixels: Primarily found in digital cameras and less common in display screens, hot pixels appear as brightly colored dots on images, especially in low-light conditions.

Detection and Repair

Various software tools and methods exist for detecting and potentially fixing defective pixels. These tools often work by rapidly cycling the display through a sequence of colors, encouraging the malfunctioning pixel to resume normal operation. However, the effectiveness of these methods can vary, and in some cases, hardware replacement may be the only solution.

Manufacturer Policies

The policies regarding defective pixels differ among manufacturers and product types. Some manufacturers follow the ISO 13406-2 standard, which allows for a certain number of defective pixels in a display before it is considered defective. Consumers are advised to review the manufacturer's policy on defective pixels before purchasing a display.

Prevention

While it is difficult to completely prevent the occurrence of defective pixels, purchasing displays from reputable manufacturers with strict quality control standards can reduce the likelihood of encountering this issue. Additionally, handling displays with care and avoiding physical stress or extreme temperatures can help preserve pixel integrity.

See Also

• Liquid Crystal Display
• Organic Light Emitting Diode
• ISO 13406-2