https://www.thinkwiki.org/w/api.php?action=feedcontributions&user=84.174.31.109&feedformat=atomThinkWiki - User contributions [en]2024-03-28T09:53:58ZUser contributionsMediaWiki 1.31.12https://www.thinkwiki.org/w/index.php?title=Problem_with_Pixel_Error&diff=8432Problem with Pixel Error2005-07-12T19:16:16Z<p>84.174.31.109: /* What are dead pixels or dead subpixels? */</p>
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<div>This page provides information about pixel and subpixel errors.<br />
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==What are dead pixels or dead subpixels?==<br />
Dead Pixels are a phenomenon caused by the technology of LCD displays. TFT displays consist of a huge number of individual display cells, each controlled by its own transistor. I.E. a display with a resolution of 1024x768 pixels consists of 1024x768x3 = 2,36 million cells. A such enormous number makes the production of a display without any faulty cell difficult. The more strict the quality restrictions are, the more expensive the panels get, because this simply means raising the number of garbage panels.<br />
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==Types of pixel errors==<br />
Here is a listing of possible types of dead pixels / subpixels:<br />
{| cellspacing=0 cellpadding=2 border=1 style="text-align:center"<br />
! pixel type<hr />state type !! pixel !! red subpixel !! green subpixel !! blue subpixel<br />
|-<br />
| always lit || <span style="width:15px;height:15px;border:1px solid black;background-color:black;color:white;">&nbsp;&nbsp;&#183;&nbsp;&nbsp;</span> || <span style="width:15px;height:15px;border:1px solid black;background-color:black;color:#ff0000;">&nbsp;&nbsp;&#183;&nbsp;&nbsp;</span> || <span style="width:15px;height:15px;border:1px solid black;background-color:black;color:#00ff00;">&nbsp;&nbsp;&#183;&nbsp;&nbsp;</span> || <span style="width:15px;height:15px;border:1px solid black;background-color:black;color:#0000ff;">&nbsp;&nbsp;&#183;&nbsp;&nbsp;</span><br />
|-<br />
| always unlit || <span style="width:15px;height:15px;border:1px solid black;background-color:white;color:#000000;">&nbsp;&nbsp;&#183;&nbsp;&nbsp;</span> || <span style="width:15px;height:15px;border:1px solid black;background-color:white;color:#00ffff;">&nbsp;&nbsp;&#183;&nbsp;&nbsp;</span>&nbsp;<span style="width:15px;height:15px;border:1px solid black;background-color:#ff0000;color:#000000;">&nbsp;&nbsp;&#183;&nbsp;&nbsp;</span> || <span style="width:15px;height:15px;border:1px solid black;background-color:white;color:#ff00ff;">&nbsp;&nbsp;&#183;&nbsp;&nbsp;</span>&nbsp;<span style="width:15px;height:15px;border:1px solid black;background-color:#00ff00;color:#000000;">&nbsp;&nbsp;&#183;&nbsp;&nbsp;</span> || <span style="width:15px;height:15px;border:1px solid black;background-color:white;color:#ffff00;">&nbsp;&nbsp;&#183;&nbsp;&nbsp;</span>&nbsp;<span style="width:15px;height:15px;border:1px solid black;background-color:#0000ff;color:#000000;">&nbsp;&nbsp;&#183;&nbsp;&nbsp;</span><br />
|}<br />
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You can notice here, that always lit complete pixels, red subpixels and green subpixels are the most annoying ones. Also, dead pixels located closer to the center of the screen are more annoying than such located closer to the edge of the screen.<br />
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Dead pixels do not always have to be a constant phenomena. You might in fact experience your pixel in question be faulty at times and working perfectly at other times. Or you might experience it to be a little flickering. This is only logical since a faulty transistor might sometimes work and sometimes not, depending on environmental conditions or even just randomly.<br />
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{{HINT|The table above also shows you a way of detecting dead pixels and subpixels. Just use plain colored screens.}}<br />
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==The ISO 13406-2 norm==<br />
However, to give the concerned customer more transparency when bying LCD displays, the ISO norm 13406-2 was introduced, providing a basis for warranty claims. By assuring one of the classes of this specification, the producer is bound to keep that quality standard throughout the whole production series. However, Manufacturers are not necessarily going with this standard. For values for IBM displays look at [http://www-307.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-4U9P53 this page].<br />
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The values in the following table state the acceptable errors per 1 million pixels. Dead pixels form a cluster when they are within a square of 5x5 pixels.<br />
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{| cellspacing=0 cellpadding=2 border=1 style="text-align:center"<br />
! Error class !! Type 1<br />(always lit pixel) !! Type 2<br />(always unlit pixel) !! Type 3<br />(always lit or always unlit subpixel) !! Type 4<br />(clusters with more than one Type 1 or Type 3 faults) !! Type 4<br /> (clusters of Type 3 faults)<br />
|-<br />
| I || 0 || 0 || 0 || 0 || 0<br />
|-<br />
| II || 2 || 2 || 5 || 0 || 2<br />
|-<br />
| III || 5 || 15 || 50 || 0 || 5<br />
|-<br />
| IV || 50 || 150 || 500 || 5 || 50<br />
|}<br />
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==Causes for dead pixels/subpixels==<br />
* As stated above, dead pixels are an inherent feature of the technology/production process of TFT displays. How many of them are in the final displays sold is just a mater of quality control standards.<br />
* Furthermore, they can also accur at random time after production. Transistors can have faults that are not recognizable at production time. These faults may make the transistor stop working after it has been in use for a certain amount of time.<br />
* Mechanical or environmental stress (i.e. heat) can possibly damage a transistor, leading to pixel errors.<br />
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<br />
==Don't panic!==<br />
Dead pixels are a really common phenomena on TFT displays. In fact there are other things about TFT displays that matter a lot more, like brightness and contrast, picture stability, color reproduction and response time. People just tend to focus on those things that are the most obvious, that's why everyone cries for dead pixels and response time when it comes to TFT displays.<br />
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However, as stated above there can be truely annoying types of dead pixels. If their count is higher than the displays quality class permits you might get the device replaced under warranty.<br />
The best thing, however, is to look for dead pixels right after purchase (you might have a chance to return it without special reason then):<br />
* Do it three times over two days - different moods and different environemental light have an influence on your perception.<br />
* Be concious about how hard it was to find the dead pixel - if it was really hard it can't be too bothering.<br />
* Also make sure that what you consider a dead pixel isn't just a piece of dirt or dust.<br />
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==Solutions==<br />
Besides some april jokes there isn't really any solution except looking for a replacement.<br />
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However, for {{Windows}} an interesting program exists that can help you making annoying subpixels and pixels more bearable. It works by trying to compensate dead a subpixel by adjusting the values for the remaining working subpixels. This way you can i.e. get rid of a most annoying always lit red subpixel. The program is german only and a download link can be found in its german [http://www.prad.de/board/thread.php?threadid=11797 PixChanger discussion].<br />
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==External sources==<br />
* [http://www-307.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-4U9P53 IBMs page on defective pixel display replacement criteria]<br />
* [http://graphics.tomshardware.com/display/20030319/index.html "An autopsy of Dead Pixels" at Tom's Hardware Guide]</div>84.174.31.109https://www.thinkwiki.org/w/index.php?title=Category:Fedora&diff=6454Category:Fedora2005-07-12T13:58:52Z<p>84.174.31.109: /* OS Homepage */</p>
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<div>{| width="100%"<br />
<div style="margin: 0; margin-right:10px; border: 1px solid #dfdfdf; padding: 0em 1em 1em 1em; background-color:#F8F8FF; align:right;"><br />
=== Fedora Core ===<br />
This page gives an introduction to Fedora Core and an overview of related articles.<br />
</div><br />
|}<br />
{| style="margin-left:20px;margin-right:20px;"<br />
|<br />
__NOTOC__<br />
=== What is Fedora Core? ===<br />
Fedora Core is a linux distribution.<br />
<br />
=== OS Homepage ===<br />
* [http://fedora.redhat.com fedora.redhat.com]<br />
|}<br />
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[[Category:Distributions]]</div>84.174.31.109https://www.thinkwiki.org/w/index.php?title=Category:Fedora&diff=6447Category:Fedora2005-07-12T13:58:36Z<p>84.174.31.109: </p>
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<div>{| width="100%"<br />
<div style="margin: 0; margin-right:10px; border: 1px solid #dfdfdf; padding: 0em 1em 1em 1em; background-color:#F8F8FF; align:right;"><br />
=== Fedora Core ===<br />
This page gives an introduction to Fedora Core and an overview of related articles.<br />
</div><br />
|}<br />
{| style="margin-left:20px;margin-right:20px;"<br />
|<br />
__NOTOC__<br />
=== What is Fedora Core? ===<br />
Fedora Core is a linux distribution.<br />
<br />
=== OS Homepage ===<br />
* [http://fedora.redhat.com www.debian.org]<br />
|}<br />
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[[Category:Distributions]]</div>84.174.31.109https://www.thinkwiki.org/w/index.php?title=Installation_instructions_for_the_ThinkPad_T43&diff=6451Installation instructions for the ThinkPad T432005-07-12T13:55:55Z<p>84.174.31.109: </p>
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<div>*[[:Category:Debian | Debian/Sarge]] [[Installing Debian/Sarge on a Thinkpad T43 | Installation]]<br />
*[[:Category:Debian | Debian/Sid]] [[Installing Debian/Sid on a Thinkpad T43 | Installation]]<br />
*[[:Category:Fedora | Fedora Core 4]] [[Installing Fedora Core 4 on a Thinkpad T43 | Installation]]<br />
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[[Category:T43]] [[Category:Debian]] [[Category:Fedora]]</div>84.174.31.109https://www.thinkwiki.org/w/index.php?title=Installing_Fedora_Core_4_on_a_ThinkPad_T43&diff=6452Installing Fedora Core 4 on a ThinkPad T432005-07-12T13:51:37Z<p>84.174.31.109: </p>
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<div>Installation Log<br />
Fedora Core 4<br />
System components<br />
Thinkpad T43 (1871-4AG)<br />
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Preparations:<br />
* When first switched on, preinstalled Win XP immediately converted almost the entire hard disk to NTFS. The last 4 GB are occupied by a FAT partition containing IBM recovery software<br />
* Boot into Win XP and burn recovery CDs (access IBM button or start menu entry) <br />
* Boot Knoppix (3.9, http://www.knopper.net/knoppix/index-en.html) and use qtparted to reduce the size of the NTFS partition<br />
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Installation of Fedora Core 4:<br />
* DVD ISO downloaded from mirror (http://fedora.redhat.com)<br />
* Installation without any difficulty<br />
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Working out of the box:<br />
* Touchpad<br />
* Touchpad buttons<br />
* Trackpoint<br />
* LAN<br />
* USB flash<br />
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Need some attention:<br />
* WLAN (Intel Wireless 2200 BG):<br />
The driver is already included in the kernel. The only thing missing is the firmware. Apparently, this is proprietary and thus not included in the distribution. It can be downloaded however. The kernel I installed with the first upgrade (2.6.12-1.1387_FC4) includes driver version 1.0.2 (?). This driver version requires firmware version 2.2.<br />
- Download appropriate firmware from http://ipw2200.sourceforge.net/firmware.php<br />
- Extract and copy files to /lib/firmware<br />
- Configure wireless network using<br />
# /usr/bin/system-config-network<br />
* Suspend to RAM<br />
- As described on http://www.ces.clemson.edu/linux/suspend_mem.shtml<br />
- Additional comment: make sure there are no backup copys (FILE~) left in the directories. If there are, the laptop will go straight back into suspend after waking up and you have to wake it again. Backup files seem to be read as well, so that all events are processed twice.<br />
- You can restart the acpi daemon straight away using<br />
# /etc/init.d/acpid restart<br />
- You can also configure klaptop<br />
* Special keys (volume, brightness)<br />
- Install tpb and xosd from extras repository<br />
# yum install tpb xosd<br />
- If you like, you can also use the kde thinkpad configuration settings:<br />
kcontrol - System Administration - IBM Thinkpad Laptop - KMilo</div>84.174.31.109https://www.thinkwiki.org/w/index.php?title=Installation_instructions_for_the_ThinkPad_T43&diff=6446Installation instructions for the ThinkPad T432005-07-12T13:45:15Z<p>84.174.31.109: </p>
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<div>*[[:Category:Debian | Debian/Sarge]] [[Installing Debian/Sarge on a Thinkpad T43 | Installation]]<br />
*[[:Category:Debian | Debian/Sid]] [[Installing Debian/Sid on a Thinkpad T43 | Installation]]<br />
*[[:Category:Fedora | Fedora/Core 4]] [[Installing Fedora Core 4 on a Thinkpad T43 | Installation]]<br />
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[[Category:T43]] [[Category:Debian]] [[Category:Fedora]]</div>84.174.31.109