This article explains pixel behavior and image sticking on Elo LCD displays.
LCD Monitors and Pixel Behavior
LCD monitors may occasionally display a small dot that appears permanently on or off. This can show as a red, green, or blue point, or a small black dot resembling a period. In most cases, these are minor and often go unnoticed during normal use.
What Is a Pixel?
An LCD panel is made up of a fixed grid of pixels. Each pixel contains three sub-pixels: red, green, and blue.
For example, a 1280 × 1024 display contains over 1.3 million pixels and approximately 3.9 million sub-pixels. With this scale, the presence of a small number of faulty sub-pixels is expected and considered normal.
A full pixel defect (all three sub-pixels failing together) is rare. Most defects are single sub-pixel issues that occur during manufacturing. Field failures are uncommon.
Acceptable Pixel Criteria
Elo follows the ISO9241-30x:2008 standard, which defines acceptable levels of pixel defects for LCD displays.
Elo displays meet or exceed ISO9241-30x:2008 Class 2 requirements for pixel defects.
Class 2 allows:
- 2 bright pixel faults (Type 1) per million pixels
- 2 dark pixel faults (Type 2) per million pixels
- 5 sub-pixel faults (Type 3) per million pixels
Refer to the table below for detailed limits:
| Monitor Size | Resolution | Total Pixels | Type 1 Stuck "ON" |
Type 2 Stuck "OFF" |
Type 3 Sub-pixel Faults |
|---|---|---|---|---|---|
| 10.1" | 1280 × 800 | 1,024,000 | 2 | 2 | 5 |
| 12" | 800 × 600 | 480,000 | 1 | 1 | 2 |
| 15" | 1024 × 768 | 786,432 | 2 | 2 | 4 |
| 15.6" | 1366 × 768 | 1,049,088 | 2 | 2 | 5 |
| 17" | 1280 × 1024 | 1,310,720 | 3 | 3 | 7 |
| 19" | 1280 × 1024 | 1,310,720 | 3 | 3 | 7 |
| > 19" | 1920 × 1080 | 2,073,600 | 4 | 4 | 10 |
A display qualifies for warranty service only if defect counts exceed ISO Class 2 limits.
Ruling Out Video Card Issues
Not all pixel issues originate from the display. A failing graphics card can produce artifacts that resemble pixel defects.
To verify:
- Change the system resolution
- Connect the display to a different system
If the defect moves or disappears, the issue is likely with the video source, not the display.
Image Sticking (Image Retention)
Image sticking, also called image persistence or burn-in, occurs when a static image is displayed for an extended period.
This causes a temporary electrical charge buildup inside the panel, preventing pixels from returning immediately to their normal state.
Key Facts
- All display types can experience image retention
- LCDs are less susceptible than CRT and plasma displays
- LCD image retention is typically temporary and reversible
What Affects Image Sticking
- Duration of static content
- Brightness and contrast levels
- Ambient temperature
- Panel characteristics
Use screen savers, power management settings, or rotating content to reduce the risk of image sticking.
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