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Dead Pixel Test


Guest Dox
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What seems like ages ago, I bought an iPAQ 3970 and after I'd had it a while tried to play a video on it. It was only then, during a dark scene in the movie that I found the display had a stuck red pixel in the centre of the screen. Too late to return it, I cursed a bit and chalked it up to experience. The iPAQ is now gathering dust on my desk.

When T-Mobile's courier dropped of my Vario III, I looked around the web for a small pixel testing application to see if the new phone had any dead/stuck pixels. The best I could come up with were a few "little" apps that needed a meg's worth of support files installing too. ;) I tend to browse with Pocket IE in full screen mode, and figured a few simple web pages in White, Black and assorted other colours would be a quick cheap way to test the display.

So I've cobbled some together, and when I'd put them online, I figured it would be good if you could put them on a storage card too, so you could try them on a prospective device there and then, perhaps in a shop without the device have a SIM card in or a WiFi connection to use the online pages. So I zipped up some slimmed down versions of the pages, tweaked the main page to be more 240x320 friendly and am offering it to anyone who might find it useful. Either view online, or from the zip'd version, with PIE in Full Screen mode to test all the pixels without installing any extra apps.

I'm not an LCD expert, or an HTML guru either, so if anyone wants to offer suggestions about either my choice of colours, or html skills, feel free... :(

The online version is here, or you can grab the zipped up offline version here or attached to this post. I hope they're of use to somebody... :D

Regards,

Dox.

PixelTest.zip

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Guest dolbe666
What seems like ages ago, I bought an iPAQ 3970 and after I'd had it a while tried to play a video on it. It was only then, during a dark scene in the movie that I found the display had a stuck red pixel in the centre of the screen. Too late to return it, I cursed a bit and chalked it up to experience. The iPAQ is now gathering dust on my desk.

When T-Mobile's courier dropped of my Vario III, I looked around the web for a small pixel testing application to see if the new phone had any dead/stuck pixels. The best I could come up with were a few "little" apps that needed a meg's worth of support files installing too. ;) I tend to browse with Pocket IE in full screen mode, and figured a few simple web pages in White, Black and assorted other colours would be a quick cheap way to test the display.

So I've cobbled some together, and when I'd put them online, I figured it would be good if you could put them on a storage card too, so you could try them on a prospective device there and then, perhaps in a shop without the device have a SIM card in or a WiFi connection to use the online pages. So I zipped up some slimmed down versions of the pages, tweaked the main page to be more 240x320 friendly and am offering it to anyone who might find it useful. Either view online, or from the zip'd version, with PIE in Full Screen mode to test all the pixels without installing any extra apps.

I'm not an LCD expert, or an HTML guru either, so if anyone wants to offer suggestions about either my choice of colours, or html skills, feel free... :(

The online version is here, or you can grab the zipped up offline version here or attached to this post. I hope they're of use to somebody... :D

Regards,

Dox.

Its a novel idea that online test. a bit of a suggestion though, all the colours you need to test an lcd screen is red green blue black and white. this is due to lcd screens using RGB colour settings to produce the colours needed to produce onscreen colour combinations of any variation. so its (Red Green Blue) for colour and( Black White) for contrast although black and white are not actually colours but the lack of or increase of light intensity. lcd screen pixals have 3 colours bundled per pixal and they alternate between the 3 to produce the pixal colour needed. thats basically the RGB colour control for most mobile lcd screens

Edited by dolbe666
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White is broken.

Looks good.

Thanks for pointing that out... I've been having a running battle with OpenOffice which insisted on putting in relative links to the files when they were on a folder on my desktop. ;) Should be fixed now (trusty Notepad isn't smart enough to muck about with your work)... :(

Dox.

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Guest Swampie

Single Dead/stuck/hot pixels aren't usually a reason for rejecting or repairing of the majority of displays. ISO 13406-2 defines the number of acceptable duff pixels of various class of displays. The vast majority of displays are Class II. A few are Class I, but these tend to be high-spec, top of the range ones.

http://en.wikipedia.org/wiki/ISO_13406-2

In effect though, the majority of manufacturers stick to ISO 13406-2, which for Class II states the following duff pixels (per million pixels) are acceptable:

Hot pixels (white): 1

Dead pixels (black): 1

Stuck pixels (sub-pixel fault - R/B/G element): 5

Note: The count of each type of fault is separate, so 1 hot pixel and 1 dead pixel is fine. 2 hot pixels would not be.

It's not clear whether these figures stand for sub 1MP displays (or whether they're scaled to match the display size), but as fractions of pixels aren't really possible, I would expect the figures are rounded up to 1 if it's in the 0.x range, so in effect you probably can have 1 hot pixel and 1 dead pixel and 1 stuck sub-pixel and it'll still be to spec.

That's what most display manufacturers and retailers are sticking to at present. Whether phone retailers are up to date on the latest specs, and particularly, whether all their staff are, is another matter - but almost certainly going direct to HTC on a warranty repair will be met with refusal. The leaked HTC Wizard service manual stated those above figures for the QVGA display (1/1/5), and I can't imagine they've relaxed their criteria whilst display manufacturers have tightened them.

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Its a novel idea that online test. a bit of a suggestion though, all the colours you need to test an lcd screen is red green blue black and white. this is due to lcd screens using RGB colour settings to produce the colours needed to produce onscreen colour combinations of any variation. so its (Red Green Blue) for colour and( Black White) for contrast although black and white are not actually colours but the lack of or increase of light intensity. lcd screen pixals have 3 colours bundled per pixal and they alternate between the 3 to produce the pixal colour needed. thats basically the RGB colour control for most mobile lcd screens

Hi dolbe666, thanks for the comments. ;)

You're right, and I did originally think about just putting a black and a white page to cover "live" and "dead" pixels. Then, when it seemed like two minutes extra work to create the primary and additive primaries, and not much extra web/page space to put them on, I thought what the heck!

I don't know if it's possible for a pixel to work correctly in isolation, but also come on (incorrectly) when the either one or both of the other two colours in the bundle are lit, but if it is, it may show up on the single or double colour pages.

If it had meant hours of extra work, or a couple of megs of extra download for the offline version I'd have gone with your point of view. However, even if my neighbouring colours idea is complete bobbins, the other colours are quite pretty. :(

Dox.

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I did post some where, not sure if it's this forum, that many tytn 2 that left the factory with dead pixels, mine had a white pixels, but I have like 14 days for exchange, along with a few other ppl.

I have two program in the exe. extention, that you execute on the phone to check pixels, and one of them will actaully repair them, well 70% chance, but you need to leave your phone one running for hours.

kms

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