Checking for dead pixels on a laptop.

  [DELETED] 15:48 23 Apr 2006
Locked

How do you set about checking a new laptop for dead pxels?

Cheers.

  [DELETED] 15:50 23 Apr 2006

Look at the screen ?

Seriuosly though - this page click here shows you how to do a decent test at all colours.

  [DELETED] 15:51 23 Apr 2006

Look at the screen ?

Seriuosly though - this page click here shows you how to do a decent test at all colours.

  [DELETED] 15:55 23 Apr 2006

Taken from an article I read,

"Before trying to grasp the meaning of a dead pixel, first you need to understand the technology behind LCD displays. An LCD display is essentially made up of pixels. Each pixel is made up of red, blue and green valves. The valves in each colour either block or pass the light source. By manipulating the amount of light passed through, each pixel displays a distinctive colour on screen. Pixels consisting of these valves are what make up the image that is ultimately displayed on the screen. A typical monitor has millions of pixels. A dead pixel refers to a pixel with a defect in its ability to display the correct colour output. It may look like a tiny black spot on your screen, or any other colour that does not correspond to what the actual image should look like"

Cheers Chris.

  [DELETED] 15:56 23 Apr 2006

Just look at the screen on a still picture, or black.

If you can't see a white pixel on a black screen, it shouldn't worry you.

on the other hand a black pixel on a light spot shouldn't cause you any bother.

the only time you may have a problem is if a white pixel is near centre of screen, then your eyes may be drawn toward it, and you could find it annoying..

No screen is perfect, and usually they are made so any duff pixel automatically goes to black..

a few dead pixels are acceptable on all laptop sreens, I think the average allowance is about eight.

  [DELETED] 15:59 23 Apr 2006

To regulate the acceptability of defects and to protect the end user, ISO have created a standard for manufacturers to follow. ISO 13406-2 recommends how many defaults are acceptable in a display before it should be replaced, within the terms & conditions of warranty.
All reputable manufacturers conform to and support the ISO 13406-2 standard.

The table below shows the allowable number of malfunctioning pixels that are acceptable, depending on the native resolution of the LCD and allowing for 2 malfunctioning pixels per million pixels.
Native resolution No. of pixels No. of million pixels Acceptable defects
1024 x 768 786,432 0.8 2
1280 x 1024 1,310,720 1.3 3
1600 x 1200 1,920,200 1.9 4
2048 x 1536 3,145,728 3.1 6

The table below shows the allowable number of malfunctioning sub-pixels that are acceptable, depending on the native resolution of the LCD and allowing for 5 malfunctioning sub-pixels per million pixels.
Native resolution No. of pixels No. of million pixels Acceptable defects
1024 x768 786,432 0.8 4
1280 x 1024 1,310,720 1.3 7
1600 x 1200 1,920,200 1.9 10
2048 x 1536 3,145,728 3.1 16

The table below shows the allowable number of malfunctioning sub-pixels that are acceptable within a 5 x 5 block of pixels, depending on the native resolution and allowing for 2 malfunctioning sub-pixels within a 5 x 5 block, per million pixels.
Native resolution No. of pixels No. of million pixels Acceptable defects
1024 x 768 786,432 0.8 2
1280 x 1024 1,310,720 1.3 3
1600 x 1200 1,920,200 1.9 4
2048 x 1536 3,145,728 3.1 6

The above is relevant to Class II LCD panels.

  [DELETED] 16:01 23 Apr 2006

It's not posted how it should have done. Here's the full article click here

  [DELETED] 16:13 23 Apr 2006

Very many thanks guys for your very precise replies. I checked from the site that you sent me DieSse and could not find one dead pixel. It´s an Acer laptop and did expect to find at least one or two - but there you go!

Cheers again.

  [DELETED] 16:33 23 Apr 2006

If you are happy, don't forget to tick as solved.

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