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Steve_L
24-06-2004, 10:52 AM
Do LCD screens have a longer life than CRT screens?

I will be upgrading to a new system and cannot decide if LCD is the way to go. They are of course more expensive but I seem to recall reading that the only long-term replacement needed is a small bulb that will eventually burn out - if true, this is a big advantage over a CRT since if it burns out then it is virtually non repairable.

A 17 inch LCD is appealing, but in Wellington yesterday (at ATech Computers) they had a 19 inch CRT with incredible resolution. I want a screen for video and photo editing and possibly for viewing DVD movies (but not for gaming). I have heard that CRTs still have a better refresh rate and resolution compared to LCDs. Would I be disappointed with a LCD ? If LCDs last longer would they be a better buy in the long run e.g over 5 or 10 years?

Thanks -- Steve L

Winston001
24-06-2004, 11:10 AM
LCD televisions are claimed to have a life of 45,000 hours so a good quality comp screen should be similar.

My belief was that a CRT was better than an LCD for photos, gaming, video etc. But others disagree. See this thread

http://pressf1.pcworld.co.nz/thread.jsp?forum=1&thread=47422&message=273074&q=CRT#273074

Rob99
24-06-2004, 11:20 AM
Godfather explains here (http://pressf1.pcworld.co.nz/thread.jsp?forum=1&thread=47116&message=270025&q=lcd+crt+life+screen#270025)

Steve_L
25-06-2004, 12:06 AM
Thanks guys. Godfather says "Life is limited by the backlight. New screens seem to be rated at 60,000 hours. 6 years +"

.... but I still wonder if the "backlight" he mentions can be replaced. It is still not clear to me. After 60,000 hours (that is a LOT of time!!) can the backlight be replaced? If so, then this is a BIG advantage over CRTs when they burn out and have to be junked.

By the way, I went into our local newspaper this afternoon (had a fantastic photo with a story that they will print tomorrow) and lo and behold the reporter-journalist-editor-or whatever they are called had a 17in Ultrasharp LCD screen - as seen in current Dell systems; she raved about how good it was and she was processing photos as I stood there.

Reading Godfather's account (as per the link given above), another thing is not clear: can LCD screens be damaged, i.e. scratched - or do some of them have glass over them to protect the screens?

willie_M
25-06-2004, 12:10 AM
But, much better things may be coming along by 2010...

Holographic screens anyone?

metla
25-06-2004, 12:10 AM
Perhaps this person raving about the screen should have mentioned they don't display colours correctly.

And once you've seen a near brand new screen with a couple stuck pixels that aren't covered by warrenty you won't be at all worried about the backlight.

Steve_L
25-06-2004, 12:11 AM
..... just to clarify..... Godfather states that there IS glass..... but maybe it was a typo error on his part. I don't think there is glass over LCD screens but maybe on some newer models??

To shell out extra $$ for a 17in LCD, and then to have my wife or some visiting kid scratch it with a ring, finger nail or pencil - egad!!!

Steve_L
25-06-2004, 12:15 AM
"with a couple stuck pixels that aren't covered by warrenty"

Egad again! I recall a friend who dropped his laptop (he is old and has the shakes and is an absent minded type) and wound up with only half a viewable screen. I guess LCD screens are easier to drop since they are so light and easily movable compared to heavy CRTs that are moved slowly with care.

Was set to go with an LCD but now I dunno. :(

metla
25-06-2004, 12:16 AM
a comparison.

http://compreviews.about.com/library/weekly/aa-crtvlcd.htm

putting lcd vs crt into google pulls up a boatload of articles.

and putting crt vs lcd into google pulls up another entirely different boatload.

metla
25-06-2004, 12:19 AM
You don't need to drop them to get a dead pixel,its a weakness in the tech and can happen at anytime to any lcd,irrilvent of which brand or how much you pay.

I would stress paying the extra and purchasing a screen with a 3 year stuck pixel warrenty,and make sure its in writing.

Pheonix
25-06-2004, 12:20 AM
Economics again rears it's head. To make them cheaper , a number of manufacturers are integrating the backlights into the unit. This makes them "throw=away" items.

Metla is right too, each manufacturer has their own method of working out what positon/number/light or dark dead pixels constitute a replacement under warranty. They can even arrive with a couple of dead pixels and not be covered by warranty.

You pays your money and you take your chances.

Coming soon that may be more economic, is organic displays. Mmm hold there a moment...just got to feed my display. :D

willie_M
25-06-2004, 08:08 AM
*chrunch munch crunch* mmmm

:D

Sb0h
25-06-2004, 09:48 AM
Many of the new LCD's come with zero dead pixel guarantees, if you see a dead pixel on it they replace it. I have just received (start of this month) a Samsung Syncmaster 172x and it is used for video, gaming, commercial web design and a bit of photo editing. I have no problem with the colours or the response of the display. The first time I played Far Cry on it I had to muck about for a bit setting up the contrast and brightness to display the black correctly but now I don't even notice I'm playing on a LCD. LCD's have come a long way recently and colour rendering is quite acceptable IMO. DVD's look fine on it although not as good as a widescreen TV (obviously). Of course the quality of the monitors varies quite a bit and it is best to do your research and see a few before you make your choice. The best thing about an LCD.....the great expanse of workspace left on your desk when you drop kick that huge, chunky and heavy CRT out the door. I wouldn't go back to a CRT if you paid me.....well it depends how much you'd pay me ;-)

metla
25-06-2004, 10:18 AM
I would agree that they have improved, the ones I used a year ago were greatly inferior to the ones I handle now, however 90 percent of lcd's on the market do not come with a zero stuck pixel warranty and none (to my knowledge) come with a zero tolerance dead pixel warranty (dead and stuck are 2 different issues)..A dead pixel is far easier to live with then a stuck one.


The inability to display shades correctly is still an issue as far as I am aware, whether its of any real-world concern is another matter entirely.

My next monitor purchase will be an Lcd, however I have 3 17" crt's that will have to die before I part with any cash, so i should be set for a good 15 years...

godfather
25-06-2004, 10:32 AM
The "glass" referred to as being at risk from scratching is the polarising layer bonded on the front of the screen. Directly under this is a hard glass layer.

The exact make-up of the filter layer is unknown, as to being a pure glass (unlikely) or a synthetic mix (likely).

I have never seen a badly (or even slightly) scratched LCD monitor, so have the logical assumption that it is reasonably durable.

Sb0h
25-06-2004, 02:05 PM
The Sony SDMX series offer a zero dead pixel guarantee and the Viewsonic VE series offer a 12 month zero pixel fault guarantee. I would take the Viewsonic wording to mean ANY pixel fault, stuck, dead or otherwise.

FWIW I have searched intensively over my Samsung and have not found any pixel faults.

metla
25-06-2004, 02:26 PM
Thats interesting,i'll have to look into it further,i'm a big fan of worthwhile garentee's.

and if you did have a pixel fault you wouldn't have had to search for it intensivley,they stick out like dogs balls.

Sb0h
25-06-2004, 04:28 PM
Yeah, my laptop has a bung pixel and its an annoying dark spot....I thought it was dust at first and tried cleaning it away....bah cheap laptop LCD's.

metla
25-06-2004, 05:01 PM
In a strange twist of fate,trust me i never went looking for this it was sitting on the main page of madonion....

here (http://discuss.futuremark.com/forum/showflat.pl?Board=techotherhardware&Number=4011691)

lagbort
25-06-2004, 05:18 PM
my parents computers (not used for gaming) both have phillips 170B4 17inch LCD's and they are very happy with them (althugh i must say once i got my computer with an crt i oculd notice the difference when playing movies/games), but i can recall a piece of paper that came with these screens that said something about a lifetime screen replacement warranty in the event of any dead and or stuck pixels :D

Sb0h
26-06-2004, 01:06 AM
Hmmmm, interesting. I must say I was on the lookout for pixel problems when the monitor arrived, it's one thing I didn't want to see. I'm glad to say I haven't seen any yet and hopefully they won't appear later. Overall I am very pleased with this LCD, makes the six week backorder not seem so bad now.
As monitor manufacturers move to migrate people from CRT to LCD they will have to offer better guarantees and "no-pixel defect" guarantees will become more and more common.

Growly
26-06-2004, 08:35 AM
LCDs are easy on the eyes because of the lack of refresh rate, ie no flicker. This makes them great for working and such, but only, in my experience, if they are set to their highest resolution. Because they can't change their screen size, they to shift their pixels around to make it look as if it was at a lower resolution, which compromises clarity.

So the first thing you should do is set it to its highest capable resolution. This can actually be harmful if you have bad eyesight - oh dear.

But it really depends on what you pay, as others have said; two of my friends use LCDs, one is just great for gaming because the refresh rate for each pixel is low, and the other's is horrible - the response time of those pixels give me headaches.

They do, as others have mentioned, take less space, and often that is the deciding factor. Personally, I have a "flat" CRT, which is just dandy. The laptop I am using now's TFT is too bright for my liking ( I am a creature of the night ..... )

As for dead pixels, I think that the warranty is a must. And I think the easiest way to do that is to make your screen completely white. (Easiest way to do that in windows is to make a white picture and set it as the screensaver). To protect from scratches, why not leave the protective plastic that comes with the thing on it?

Graham L
26-06-2004, 03:37 PM
LCD and TFT screens all are built between two sheets of glass , with a very good seal around the edges. It's "glass" glass.

It breaks when hit hard enough. There must be many millions of broken screens around these days (lots of cellphones get dropped. :D)

It's reasonably scratch resistant. But it's not idiot proof.

godfather
26-06-2004, 04:25 PM
But what you touch is not the actual glass "sandwich", but the polarising filter. Exaxctly what its made of is not readily disclosed.

Cross sectional view is here:
http://sharp-world.com/aquos/products/a.html

Steve_L
26-06-2004, 07:04 PM
Hello Guys... as the one B-) who started this thread, here are replies to your posts (bold = your's; regular text = my comments). By the way, I drove down to Wgtn yesterday and placed an order for a new PC (besides the usual, it will be for video and photo editing but not for gaming). The hardest decision was choosing the monitor and in the end I went for a 19in Philips CRT but now realise that there will be no decent place to put the two speakers on my computer desk - therefore I may ?:| change the order to a 17in flat CRT unless I can find a decent LCD guarantee - but see my comments below.


To make them cheaper , a number of manufacturers are integrating the backlights into the unit. This makes them "throw=away" items.

Now it seems to me that this is important - to know if the backlight can be replaced. If the backlight burns out after the guarantee period and before the expected 60k hour lifetime, then this would be a hell of a situation.X-(


The best thing about an LCD.....the great expanse of workspace left on your desk.

I'll have to pull my computer desk away from the wall another 5 cm if I get the 19in CRT. No problem but I am in the living room and the further away from the wall, the more the mess of wires is exposed. My old 17in CRT is heavy enough but the 19in would have to be an anchor. Add a point for getting an LCD.


a Samsung Syncmaster 172x and it is used for video, gaming, commercial web design and a bit of photo editing. I have no problem with the colours or the response of the display.

THIS is very useful info. Thanks. I'll check to see if they are still available; failing this, I guess what I would have to do before deciding on an LCD is to watch a movie on it, or something else that demands a good refresh rate. I wonder if SYNMASTER means that it has a great refresh rate or ???


90 percent of lcd's on the market do not come with a zero stuck pixel warranty and none (to my knowledge) come with a zero tolerance dead pixel warranty (dead and stuck are 2 different issues)..A dead pixel is far easier to live with then a stuck one.

What is the difference between a dead and a stuck pixel? Is one black and the other white? Whatever... getting a decent warranty (zero problems with pixels) seems to be a MUST. Yesterday in Wgtn the sales/tech guy who served me (he was super - knew heaps and was very helpful) said that with most LCDs, if you buy it, take it out of the box, plug it in and find a few dead/stuck pixels, then it is tough luck cuz there is no warranty that will cover it. Jeeesh! So I pay 700 bucks for a bum screen and I cannot return/exchange it??!!! X-( X-(


The "glass" referred to as being at risk from scratching is the polarising layer bonded on the front of the screen. Directly under this is a hard glass layer. ... I have never seen a badly (or even slightly) scratched LCD monitor, so have the logical assumption that it is reasonably durable....but then another person says LCD and TFT screens all are built between two sheets of glass , with a very good seal around the edges. It's "glass" glass.

Well, actual glass or not, I too have never seen a scratched LCD screen.

The Sony SDMX series offer a zero dead pixel guarantee and the Viewsonic VE series offer a 12 month zero pixel fault guarantee. I would take the Viewsonic wording to mean ANY pixel fault, stuck, dead or otherwise.

Another EXCELLENT bit of info. Thanks. If movies look good on a Viewsonic VE, then this would be a good choice.


From the link that was given:
http://discuss.futuremark.com/forum.....
I see this: <<Re: Just got the Samsung 172X! - I'm extremly pleased with mine...though I had to go through 3 of them before I got one without any dead pixels. // Samsung says its 10 dead pixels in order for a replacemnet or a fix.>> Other comments on this thread referred to the fact that the shop (Best Buy, I guess in USA) has a no problem refund policy for a period of 14 days or maybe it was 30 days - sounds good to me.




LCDs are easy on the eyes because of the lack of refresh rate, ie no flicker. This makes them great for working and such, but only, in my experience, if they are set to their highest resolution. Because they can't change their screen size, they to shift their pixels around to make it look as if it was at a lower resolution, which compromises clarity...So the first thing you should do is set it to its highest capable resolution. This can actually be harmful if you have bad eyesight - oh dear.

Sorry but this does not make sense to me. You first say LCDs are easy on the eyes at the highest resolution but then you say it could be harmful with bad eyesight. ?? And what is meant by "bad" eyesight?


But it really depends on what you pay, as others have said; two of my friends use LCDs, one is just great for gaming because the refresh rate for each pixel is low, and the other's is horrible.

From what I have picked up, I believe the best refresh rate is 20 milliseconds (or whatever the unit) which is still far from a CRT. But if it looks good while gaming and when viewing a movie, then that is all that matters.


>>>THANKS for all of the feedback. The way I feel now is to go for a 17in flat CRT instead of the 19in which will max out the space for a screen in my computer desk, meaning that the two small speakers would have no decent place to sit. But an LCD screen would look VERY cool so if I can find a decent warranty against dead/stuck/junk pixels, and can live with the pain of spending an extra 6-700 bucks, then I'll get an LCD.

agent
26-06-2004, 08:50 PM
I'm not quite sure what Megaman meant too, but there is something you should know about resolutions on LCDs.

If you get an LCD, you'll want to watch for it's native resolution. This is the ideal resolution that you should run it at - larger resolutions mean it is trying to fit more into one real pixel than it normally does, and so things will start to look blurry (though this shouldn't be very noticeable if you stick close to the native resolution). Similarly, you wouldn't want to go under the native resolution too much, because again, the quality of the images displayed will deteriorate.

The lowest response time for LCDs at the moment is 12ms, I believe. The Samsung SyncMaster 172x sports this response time. 16ms appears to be the standard for the moment though.

The April issue of PC Authority did a round up of 23 17" LCDs. The top one was the Acer AL1751W (which is a widescreen LCD monitor) - going for $930 at the moment, according to PriceSpy (http://www.pricespy.co.nz).

Megaman
26-06-2004, 09:54 PM
> I'm not quite sure what Megaman meant too, but there
> is something you should know about resolutions on
> LCDs.

???

kiki
26-06-2004, 09:55 PM
I saw LCDs were down to 10ms on Anandtech less than a month ago, but can't find the article now.

Growly
26-06-2004, 11:36 PM
Sorry, I should have made myself clear.. ( I was on the hills in the back seat of the car while being driven home, with a latop while posting)

LCD screens have no refresh rate like CRT screens do. This makes it easier to look at, because your eyes are not being hit light 60 times a second, rather they are hit more and so you don't notice it.

For this reason, they are nice for the eyes.

Ironically, the bad part is that LCDs, being LCDs (as someone else has also said), cannot change the size of their display. The are constantly displaying with every single pixel they have. A CRT screen can use as many pixels as it wants (in theory). For this reason, when at lower resolutions, CRT screens just display fewer but bigger pixels, meaning the picture still looks the same, just zoomed in.

An LCD has a fixed pixel size, so when you want to make the the resolution (how many pixels it displays) smaller, it has to combine a few pixels into one, while leaving other pixels on their own. This gives a very uneven and messy look. The counter-act this, LCD screens are best when they are displaying at their highest resolution, because then every pixel they have is being used as an individual pixel, and not as a part of an uneven clump.

Because the highest resolutions are large (1240 x 1024 ish), it makes everything small, which is bad for people with vision that struggles to read small things at shot distances. I apologise for saying "bad" eyesight, I'm afraid that I am a victim of common generalisation and colloquial attitude :D:D:D:p

I know i can't explain very well, but there you go, I tried...

Winston001
27-06-2004, 12:01 AM
for people with vision that struggles to read
> small things at shot distances

Well I can certainly understand that Growly! I'd have great difficulty on reading anything at a shot distance. I imagine I'd have other concerns. ;)

Steve_L
27-06-2004, 10:29 AM
Hello Guys - I am working on replies to what you have said since my last post yesterday. In the mean time, have a look at the following info found on: http://www.lcd-monitor-reviews.com
This is an excellent site and has links to other sites. The only gripe I have with "lcd-monitor-reviews" is that they don't date their reviews, so we cannot tell how current the info is. More to come from me later this morning..... Cheers - Steve_L

"There are some lemons out there and some crazy monitor pricing you can take advantage of. You can save HUNDREDS of DOLLARS so make sure you make an informed choice before parting with your cash."

With a response time of 16ms this monitor would be ideal for games. ... The major problem with this monitor is that it only has an analog input. This means if you can never connect this monitor up digitally. Digital connectors do offer some benefits and it's starting to become really commont for LCD computer monitors to support them.

LCD monitor dead pixel guide...
Dead pixels are not the major issue they used to be. Manufacturing techniques have improved to the point that there are far fewer monitors produced with dead pixels that ever before.

As of writing this the best brands are:
Lite On, Phillips and Hitachi. All three have a zero tolerance to dead pixels but Phillips doesn't count unlit pixels as dead.

If you do a lot of image editing you'll want a contrast ratio of at least 700:1

If you want to play games then you'll need a response time 20ms or below.

Steve_L
27-06-2004, 12:10 PM
Hello again guys...
DVI input - anyone considering buying an LCD screen should, imho, be sure it has DVI. You will probably be sorry at sometime in the future if your new screen has only analogue input.

>agent wrote: The lowest response time for LCDs at the moment is 12ms, I believe. The Samsung SyncMaster 172x sports this response time. 16ms appears to be the standard for the moment though.... The April issue of PC Authority did a round up of 23 17" LCDs. The top one was the Acer AL1751W (which is a widescreen LCD monitor) - going for $930 at the moment, according to PriceSpy.

Thanks for the PriceSpy referral - I had a look there and at Ascent (NZ), and have found that the best 17in LCDs are a good more expensive - around 850 or more. I am going over to a friend's house today - he has a 17in Philips, bought at the same store where I am getting my new PC (Atech, Wellington). He is happy with it, including game playing, and has no bad pixels. If I choose to go with an LCD, maybe Atech will let me check the screen for bad pixels before paying.


>Growly wrote: Because the highest resolutions are large (1240 x 1024 ish), it makes everything small, which is bad for people with vision that struggles to read small things at shot distances.

An excellent explanation. Thanks. Considering you first wrote on your laptop in the back seat of a moving car, your writing is commendable. ;)


>I wrote (from LCD Monitors Review web site): Lite On, Phillips and Hitachi. All three have a zero tolerance to dead pixels but Phillips doesn't count unlit pixels as dead.

So I wonder if unllit pixels would be noticed, or not noticed to the degree of other dead pixels? ?:|


>>Here is some more info on warranties, from http://www.lcd-monitor-reviews.com
Lite On, Phillips and Hitachi: All three have a zero tolerance to dead pixels but Phillips doesn't count unlit pixels as dead. HP will only replace a monitor with there are 4 scattered faulty pixels or 3 clustered. LG will replace a monitor if there are 2 within a 10cm circle. NEX-NEC will replace 3 lit, 3 unlit or 6 color. Samsung could try harder. Six dead pixels allowed on a 15", or nine on a 17", are too many. Sony will replace if on a 15" panel there is 2 lit, 2 unlit or 4 dead. On 17" panels Sony will replace if there are 3 lit, 3 unlit or 7 dead. Viewsonic will replace if on a 15" panel there is 2 lit, 2 unlit or 4 dead. On 17" panels Viewsonic will replace if there are 3 lit, 3 unlit or 7 dead.

Egad - what a mess with warranties! :O What a load of rubbish - for manufacturers to have a consumer shell out big bucks for their LCD and expect them to be content with the likes of "2 lit, 2 unlit or 6 dead" (acceptable for Sony). X-(

> From my post above: If you want to play games then you'll need a response time 20ms or below.
What about watching movies - the same response time of 20ms or below?

>>>Does anyone know of a NZ computer store that has a shop money-back / right of exchange guarantee for LCD monitors? I guess DSE Dick Smith and Noel Lemmings would be a good bet so I will check their prices.

Cheers - Steve

Sb0h
27-06-2004, 12:24 PM
Trying before you buy is a great idea, especially if you can take a DVD you are familiar with into the shop. Bear in mind that the LCD in the shop may require a bit of setup in order to get the best out of them, ie contrast and brightness etc. Most monitors should come with some type of setup application which makes this process a bit easier.

Also as far as the dead pixel issue goes....get the shop to open the box and let you see the monitor running before you purchase it, explain you are concerned about the pixels and you want to physically check the monitor before you buy it. I think most stores offer a 7 day return of you are unhappy with the purchase...someone here may know the legalities of the Consumer Guarantees Act. In either case you are pretty well protected I think. If you are unhappy then you can get your money back or exchange for a different product. I see Noel Leeming offers a 28 day exchange guarantee now....maybe we will see this from other stores as well?

I have to say choosing an LCD was a big decision for me also. My PC is used for all manner of tasks and I was concerned that the display should perform well for all of them. I read many reviews and did a lot of research on forums etc to see what other people thought of various brands. It did take a hour or two to get used to the monitor (they just look different) but now I don't even notice it, except for the fact it is only a couple of cm thick and looks dead sexy :x

Have fun with your new PC.

Sb0h
27-06-2004, 12:34 PM
As far as noticing dead pixels, unlit or otherwise...my laptop has one stuck pixel (it is a fixed colour). It apears as a tiny dot on the screen and it always there. As I mentioned previously I originally thought it was a speck of dust, but it can't be wiped away. Initially it was very annoying as my eyes were drawn to it, but now I have to actually look for it...I must have got used to it being there. But in saying that I would not be happy shelling out a grand for a new LCD to find a bung pixel on it.

As with most things though, you get what you pay for.

agent
27-06-2004, 01:16 PM
> LCD screens are best when they are displaying at their highest resolution

This statement needs a minor correction: LCD screens look sharpest (ie, best) when they are displaying at their native resolution. Hence why it's called the native resolution.

The native resolution and an LCDs top resolution are always (read: in most cases that you will find) different, as far as I have seen. Has anyone seen an LCD with a native resolution of 2048x1536, or higher?

So the main things you want to be looking out for a decent native resolution (most these days are higher than 1024x768), a good contrast ratio (higher is better), digital and analogue inputs, perhaps power consumption, and an excellent pixel warranty.

And now, without making this post too long, I'll tell you some basic stuff you should try testing on an LCD that you are thinking of buying.

Firstly, you'll want to get the whole displaying a single colour - go through red, green, blue, black, and white. This can be done easily with a simple HTML file and putting Internet Explorer into kiosk mode, or via Paint, or similar. Look for any subtle differences in colour when the LCD is displaying each colour.

You'll also want to try displaying gradients - you can make one using The GIMP, Paint Shop Pro, Photoshop, etc - a simple black to white gradient would be sufficient. If the LCD cannot display this correctly (ie, it becomes banded), you might want to move on.

Steve_L
27-06-2004, 11:51 PM
>A dead pixel is far easier to live with then a stuck one.

>>>What is the difference between a dead and stuck pixel?

metla
28-06-2004, 12:03 AM
a dead pixel is just that,dull,no light.

A stuck pixel is stuck on one colour.

Fire-and-Ice
28-06-2004, 09:57 AM
Excellent advice agent. All I gotta do now is find a friendly retailer who will allow me to run all those tests on their collection of LCD screens.

If I can find any who have more than a couple of different models on display, that is. ;-)

Steve_L
28-06-2004, 10:08 AM
Thanks Metla.

By the way, here is what I found on a NZ computer sales page, for a Philips 17in LCD: ** ZERO BRIGHT DOT WARRANTY EXCLUDED **

Grrrrrrrrr.....!!!

metla
28-06-2004, 10:27 AM
> Excellent advice agent. All I gotta do now is find a
> friendly retailer who will allow me to run all those
> tests on their collection of LCD screens.
>
> If I can find any who have more than a couple of
> different models on display, that is. ;-)



Just don't buy via mail order,get them to get one in for you and have them fire it up before youe make the purchase.

Sb0h
28-06-2004, 11:07 AM
Philips LCD with zero bright dot warranty here (http://www.ascent.co.nz/mn-product-spec.asp?pid=141024). But looks like it only protects against "bright" pixels, I wonder if it also covers "dark" pixels. Best to try before you buy. Mind you I'm a good one to say that considering I bought mine online, but then I was quite prepared to send it back if I wasn't happy.

Steve_L
28-06-2004, 09:22 PM
I rang Philips today and found that they have a Zero Bright Dot warranty. Black pixels will not be covered. In any case I plan to have the retailer turn the LCD screen on so I can see if there are any bad pixels, or if Noel Leemings can order the same or similar screen I'll go with their right of return - and Fly Buys :) .

They emailed me the following, which seems fairly good to me:
Philips' Flat Panel Monitors Pixel Defect Policy
Philips strives to deliver the highest quality products. We use some of the industry's most advanced manufacturing processes and practice stringent quality control. However, pixel or sub pixel defects on the TFT LCD panels used in flat panel monitors are sometimes unavoidable. No manufacturer can guarantee that all panels will be free from pixel defects, but Philips guarantees that any monitor with an unacceptable number of defects will be repaired or replaced under warranty. This notice explains the different types of pixel defects and defines acceptable defect levels for each type. In order to qualify for repair or replacement under warranty, the number of pixel defects on a TFT LCD panel must exceed these acceptable levels. For example, no more than 0.0004% of the sub pixels on a 15" XGA monitor may be defective. Furthermore, Philips sets even higher quality standards for certain types or combinations of pixel defects that are more noticeable than others. This policy is valid worldwide.

Pixels and Sub pixels
A pixel, or picture element, is composed of three sub pixels in the primary colors of red, green and blue. Many pixels together form an image. When all sub pixels of a pixel are lit, the three colored sub pixels together appear as a single white pixel. When all are dark, the three colored sub pixels together appear as a single black pixel. Other combinations of lit and dark sub pixels appear as single pixels of other colors.

Types of Pixel Defects
Pixel and sub pixel defects appear on the screen in different ways. There are two categories of pixel defects and several types of sub pixel defects within each category.
Bright Dot Defects Bright dot defects appear as pixels or sub pixels that are always lit or 'on'.

Black Dot Defects Black dot defects appear as pixels or sub pixels that are always dark or 'off'.

Pixel Defect Tolerances
In order to qualify for repair or replacement due to pixel defects during the warranty period, a TFT LCD panel in a Philips flat panel monitor must have pixel or sub pixel defects exceeding the tolerances listed in the following tables.

Steve_L
28-06-2004, 09:24 PM
>>>They emailed me the following

"They" meaning Philips, not Noel Leemings.

- Steve

Sb0h
28-06-2004, 09:33 PM
Thanks for that, it's nice to have an explanation from the manufacturer regarding their warranty.

metla
28-06-2004, 10:07 PM
>In order to qualify for repair or replacement due to pixel defects during the warranty period, a TFT LCD panel in a Philips flat panel monitor must have pixel or sub pixel defects exceeding the tolerances listed in the following tables.


Do you have the data from the tables mentioned?

Steve_L
29-06-2004, 08:43 AM
Hello Metla,

In the next few minutes, will email (where you work) you the html file that has the tables.

Cheers, Steve

Steve_L
29-06-2004, 08:53 AM
In summary, the Philips pixel policy is this:

The "B" and "P" models of LCD screens, e.g. 170B, have ZERO tolerance to bright dots. But the cheaper "S" models can have 4 or fewer as acceptable unless the dots are adjacent where 1 or 2 are acceptable.

BLACK DOTS: For all models, 4 or fewer are acceptable unless adjacent where only 1 is acceptable for B and P models, and 2 or fewer for S models.

I wonder if anyone knows of the Viewsonic pixel warranty?

>>This post did not seem to get through so is being sent twice.

- Steve

Steve_L
29-06-2004, 08:08 PM
From Viewsonic web site:
http://www.viewsonic.com/support/qa.cfm?topic=lcd&question=01

[ It is not as good as Philip's pixel warranty. ]


LCD Pixel Criteria

ViewSonic is committed to customer satisfaction by providing the highest quality products in the industry. The result is that our LCD displays generally have very few non-performing pixels. For example, an 18" SXGA (1280 x 1024) display has nearly 4 million sub-pixels. A product exhibiting 7 non-performing pixels would equate to an extremely small 0.00018 percent of the total sub-pixels.

(1280 Horizontal Pixels) * (1024 Vertical Pixels) * (3 sub-pixels per pixel) = 3,932,160 sub-pixels

[(7 non-performing pixels) / (3,932,160 sub-pixels)] * 100% = 0.00018%

To ensure the highest performing displays, ViewSonic sets limits as to the allowable number of pixel anomalies. ViewSonic has adopted the following pixel criteria to supplement our existing three-year limited warranty. This policy applies to all ViewSonic LCD displays during the warranty period.

ViewSonic sets limits on 14" - 15" LCD's at 4 bright sub-pixels, 4 dark sub-pixels, or a combination of 4.
ViewSonic sets limits on 17" - 19" LCD's at 7 bright sub-pixels, 7 dark sub-pixels, or a combination of 7.
ViewSonic sets limits on 20" & greater LCD's at 10 bright sub-pixels, 10 dark sub-pixels, or a combination of 10.

It is possible that any replacement display may also have some non-performing sub-pixels. This should be considered when requesting a warranty exchange.

Steve_L
29-06-2004, 08:15 PM
>>>Crikey! Wonder why the text above is all underlined? I did not add anything....