I seem to remember some site recently that gave the dead pixel information for LCD manufacturers and other warrenty stuff. Does anyone know where i could find that info? Any brand recommendations for LCDs?
I am terribly happy with my Dell 1900FP, which is just a re-branded Samsung flat panel. I've bought three of them and not one dead pixel amongst all three.
has an article (near top of page) reviewing a Samsung 172T. One thing he mentions is that Samsung will replace an LCD monitor even with only ONE bad pixel - and pick up the shipping charge free to boot.
He's in Australia, so you might want to check US policy.
Most manufacturers tell you to lump it if you have a few bad pixels, so Samsung looks pretty attractive from that viewpoint.
I cribbed this from a site called neqx.com:
*********************************
LCDs & DEAD PIXELS
BACKGROUND:
A 1280x1024 LCD Display has a total of 1,310,720 pixels. Each pixel has 3 pels (1 red pel, 1 blue pel, & 1 green pel). The total number of pels on a 1280x1024 LCD is 3,932,160.
Assume that the chance of a single pel failing is 1 chance out of 1,000,000. Given that there are 3,932,160 pels on the 1280x1024 LCD, the odds are, that there will be a few dead pels in the display.
While manufacturing could always trash an LCD that has 1 or more dead pels, the cost of this waste would need to be added to the cost of the panels being sold to cover the loss. Considering that the price of LCD Displays is already high, this would not be a good idea. Thus, manufacturers of LCDs allow some dead pixels (pels) in their products.
INDUSTRIAL SUMMARY:
Most manufacturers do not wish to talk about the number of allowed missing pixels nor publish them officially in product specifications. However, some of the replacement standards have been documented in different places.
Company Model Dead Pixels Allowed
CTX 745 10
HP 1024 1 pixel, 15 pels on, 18 pels off
NEC LCD400 Depends on the number / location
Sceptre FT15 9
ViewSonic VP140 7, 2 if adjacent
Source: Computer Shopper, January 20, 1999
Company Model Dead Pixels Allowed
Iiyama 38b 13 pels or 3 consecutive spots
Mitsubishi LCD50 6 or 3 adjacent
Philips 151AX replace at 10 or more
Samsung 520TFT 4 bright, 7 dark, or 2 adjacent
Seceptre BT15 18
IBM Comments:
Source: Windows Magazine, April 1998:
"Vendors with high standards for quality control tolerate very few bad pixels and would fail a panel with visible defects or as few as a dozen or so dead pixels scattered about the screen. Others may be more tolerant. . ..Alan Petersburg, IBM's worldwide brand manager for visual products."
Source: IBM-Austria - PC-HW-Support 11 Jul 99 WEB Pages
"2640 ECA007 - LCD PIXEL POLICY CHANGE . . . The IBM ThinkPad pixel policy pertaining to LCD replacement has changed. The old policy required 21 or more defective pixels to replace the TFT LCD panel during warranty. This policy has been revised to read 8 or more defective pixels."
NOTE: While this refers to the LCD in an IBM notebook computer, it does show that IBM allows for dead pixels in their displays.
CONCLUSION:
While manufacturers of LCD Displays would like to have zero dead pixels (or pels) in 100% of their products, the current state of the art in technology does not make this possible within a reasonable cost. Even the high end manufacturers consider 5 to 7 dead pixels (or pels) within the allowed specification.
***********************************
I know if I laid out the $$$ for a big LCD and was told to live with 8 bad pixels (IBM) I would be mighty irked.
There have been a series of articles on THG covering lcds. They describe the standards and the rules that different mfgs use.
Some mfgs will not tell you what their policy is!
Stay away from them.
Yeah haha, Samsung Australia has a phenomenal dead pixel policy. Samsung has extremely tight quality control with perhaps the most stringent of requirements before they ship off any of their products.
Comments
http://www.planar.com/monitors/PL150.asp
(I will be looking for a 15" screen)
~dodo
http://www.dansdata.com/
has an article (near top of page) reviewing a Samsung 172T. One thing he mentions is that Samsung will replace an LCD monitor even with only ONE bad pixel - and pick up the shipping charge free to boot.
He's in Australia, so you might want to check US policy.
Most manufacturers tell you to lump it if you have a few bad pixels, so Samsung looks pretty attractive from that viewpoint.
I cribbed this from a site called neqx.com:
*********************************
LCDs & DEAD PIXELS
BACKGROUND:
A 1280x1024 LCD Display has a total of 1,310,720 pixels. Each pixel has 3 pels (1 red pel, 1 blue pel, & 1 green pel). The total number of pels on a 1280x1024 LCD is 3,932,160.
Assume that the chance of a single pel failing is 1 chance out of 1,000,000. Given that there are 3,932,160 pels on the 1280x1024 LCD, the odds are, that there will be a few dead pels in the display.
While manufacturing could always trash an LCD that has 1 or more dead pels, the cost of this waste would need to be added to the cost of the panels being sold to cover the loss. Considering that the price of LCD Displays is already high, this would not be a good idea. Thus, manufacturers of LCDs allow some dead pixels (pels) in their products.
INDUSTRIAL SUMMARY:
Most manufacturers do not wish to talk about the number of allowed missing pixels nor publish them officially in product specifications. However, some of the replacement standards have been documented in different places.
Source: PC Magazine Online, www.zdnet.com/pcmag/features/lcd/lcd-s2.htm
Company Model Dead Pixels Allowed
CTX 745 10
HP 1024 1 pixel, 15 pels on, 18 pels off
NEC LCD400 Depends on the number / location
Sceptre FT15 9
ViewSonic VP140 7, 2 if adjacent
Source: Computer Shopper, January 20, 1999
Company Model Dead Pixels Allowed
Iiyama 38b 13 pels or 3 consecutive spots
Mitsubishi LCD50 6 or 3 adjacent
Philips 151AX replace at 10 or more
Samsung 520TFT 4 bright, 7 dark, or 2 adjacent
Seceptre BT15 18
IBM Comments:
Source: Windows Magazine, April 1998:
"Vendors with high standards for quality control tolerate very few bad pixels and would fail a panel with visible defects or as few as a dozen or so dead pixels scattered about the screen. Others may be more tolerant. . ..Alan Petersburg, IBM's worldwide brand manager for visual products."
Source: IBM-Austria - PC-HW-Support 11 Jul 99 WEB Pages
"2640 ECA007 - LCD PIXEL POLICY CHANGE . . . The IBM ThinkPad pixel policy pertaining to LCD replacement has changed. The old policy required 21 or more defective pixels to replace the TFT LCD panel during warranty. This policy has been revised to read 8 or more defective pixels."
NOTE: While this refers to the LCD in an IBM notebook computer, it does show that IBM allows for dead pixels in their displays.
CONCLUSION:
While manufacturers of LCD Displays would like to have zero dead pixels (or pels) in 100% of their products, the current state of the art in technology does not make this possible within a reasonable cost. Even the high end manufacturers consider 5 to 7 dead pixels (or pels) within the allowed specification.
***********************************
I know if I laid out the $$$ for a big LCD and was told to live with 8 bad pixels (IBM) I would be mighty irked.
Prof
(Who still likes his 21" .22 dp Nokia 445Xi)
Some mfgs will not tell you what their policy is!
Stay away from them.
~dodo