bad pixel

(redirected from Dead pixel)

bad pixel

A defective pixel on an LCD screen. Bad pixels are often transistors that are permanently dead and appear as black dots or permanently energized and show up as white or colored dots ("hot pixels"). These pixel defects usually occur at the time of manufacture. However, if a bad pixel appears after the screen has been in use for some time, it may also be due to a dented or scratched polarizer (see LCD).

Sometimes, it is possible to repair a bad pixel by gently rubbing the screen with a cloth or running a pixel repair over the area for several hours, the latter repetitively flashing colors on and off to attempt to dislodge a stuck pixel.

Does It Matter?
It depends. On an LCD TV, which is displaying motion and is situated several feet from the viewer, dead or lit pixels may not matter. On a computer monitor only two feet away, they may be very annoying, especially if located in the center of the screen. Equipment manufacturers have different policies regarding defective pixels. They typically state that if a certain number of bad pixels exist when the display was purchased, the unit may be returned.


Polarizer Damage
This red pixel is due to damage on the polarizer, which is the screen layer in front of the user (see LCD).







It Can Be Annoying
One bad pixel can be very glaring, depending on where it shows up; witness the single, green pixel on this man's black coat.







Test for Yourself
Dead pixel testers such as Dead Pixel Locator from Astris.com let the user find bad spots by displaying different colors across the entire screen.







Repair Stuck Pixels
Pixel repair programs cycle rapidly through all the colors to possibly dislodge a stuck pixel. There is no guarantee, but if a stuck pixel is annoying, it is worth a try. When this animated GIF is retrieved from Killdeadpixel.com, it is placed over the stuck pixel and left alone for an hour or more.
References in periodicals archive ?
In their latest move, they are offering the “0-1 Dead Pixel Guarantee,” this beats the industry standard which is set at 0-5 dead pixels.
Other programmable features include fast global reset, exposure time, frame rate, subsampling, window size, analog and digital gain, horizontal and vertical inversion and dead pixel removal.
Founded by G4TV co-founder Scot Rubin as a distribution outlet for independent podcasters and musicians, the station has grown to include over 25 hours of live interactive programming each week from Dead Pixel Live, The Bobby Blackwolf Show, Orange Lounge Radio, The Video Game Outsiders and more.
Other programmable features include exposure time, frame rate, subsampling, window size, analog and digital gain, horizontal and vertical inversion and dead pixel removal.
3 MegaPixel image sensors significantly reduce the BOM with higher quality by providing on-chip electronic exposure control, programmable color gain, dead pixel removal, low light sensitivity and a flexible interface for wide acceptance and compatibility in the industry.
It ships with an industry leading 5-year standard warranty and a zero dead pixel policy at a low factory-direct price of just US$859.
Others reported too of dead pixels on screen and part of the display screen falling away, no thanks to shoddy craftsmanship.
The high throughput and low latency of the Camera Link standard make the frame grabber ideal for line-scan image sensors, which engineers can use for surface inspection of large areas, including finding esthetic and functional defects in solar panels and dead pixels in flat panel displays.
What's more, xVx is one of the few companies in the industry to offer a free guarantee of no partially lit or dead pixels during the system's warranty period.
The hand-selected Platinum(TM) line offers a 3-year warranty and allows a maximum of 2 dead pixels, the lowest pixel anomaly in the industry.