Choosing a LED computer monitor

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  • #1
fluidistic
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Main Question or Discussion Point

Hey guys,
I'm currently using as monitor a Flatron ez T730SH. It's been almost 4 years I have it and sometimes it would change the coloration of the whole screen (red to greenish, red-greenish over and over). Apart this I don't have any problems with it and I don't really care about the color problem.
However I'm being seduced by a thinner, better quality and much bigger monitor. I've read on the internet about LCD's and LED's. I'm tempted to buy a LED monitor. So today I went to several stores in my city (Cordoba in Argentina) and there are only a few models. I've been in approximately 5 stores.
Here are the models I can buy:
LG W2486L, 24'. (more than 600 US dollars).
LG E2350V, 23'. (about 15 dollars more expensive than the previous).
Another LG 2340, 23'. I don't know the final letter(s) of the model. This one costs "only" 435 bucks.
Another one was a Samsung 22' which costs between 400 and 500 dollars but I don't know the model so I'll check it out again.
I'm interested in at least 22-23'.

Also just to be sure, I'm currently using a monitor that refreshes 85 times per second. At 60 Hz I can notice that the screen kind of turns off and on and off and on and it's really, really, really bothering me. From 80 Hz and on I don't see any difference.
I've read that LED monitors have generally a 60 Hz refresh rate but that the screen doesn't turn off and on. It's rather on all the time and the pixels change 60 times per second. So I'm guessing it wouldn't bother my eyes? Can you confirm this?

Lastly, I would like you to advice me on which model to choose. The cheaper the better so if there's a model in my small list that "do the job" and is cheaper than the best model, I'd go for it.
Oh and I won't buy by internet, here it's not like in Western Europe or North America. I simply don't trust in the shipping due to personal (bad) experiences.
Thanks for any help.
 

Answers and Replies

  • #2
rcgldr
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So called "LED" monitors are LCD monitros that use LED's around the perimeter or in the backplane to allow sections of the screen to be lighted at different levels.

True "LED" monitors will be OLED (organic LED, where organic is a chemical reference, not that the technology is based on some earth friendly technology). Currently these are used on the Samsung Galaxy S (smart phone), some small screens on specialized devices, and Sony makes a very expensive tiny TV based on OLED's. These should start show up as mainstream devices in 1 1/2 to 2 years.

http://en.wikipedia.org/wiki/Organic_light-emitting_diode

refresh rate
On a CRT monitor, the phosphors on the screen are designed to diminish in brightness in a short period of time (called persistance). This allows for quick motion of the images, but requires a corresponding refresh rate to avoid the dimming of the phosphors to appear as a flickering screen. Usually they're designed to look good at 75hz to 85hz. As a bit of trivia, and a extreme example, IBM made a monochromatic (green) display 3270 monitor where the phosphors had a persistance of over 1 second. It was great for producing very sharp text (since it could use a very thin electron beam and still be bright), but any motion, like scrolling, would look like a terrible blur until 1 second after the motion stopped. It was mostly used in data entry environments (like banks) where a fixed form was displayed, and the user filled in the empty fields.

Getting back to your question about refresh rates on digital monitors (LCD, Plasma, OLED), the pixels remain at a fixed brightness during each frame, quickly changing in brightness on each frame. You may be able to get response rate time for the pixels in the specification (usually the time it takes to make a 50% range change, a 100 % change is rarely specified). Contrast is limited by the range of blockage of light by the technology, generally an issue for dark scenes on LCD based televisions. To improve the quality of fast motion images, some digital monitors can refresh at 120 hz. However this can be an issue for some video cards, like the ATI HD5000 series cards, which have a max rate of 85hz, and due to some bug, are forced to 60 hz if resolution is 16x9 ratio.

LCD monitors - number of colors
LCD monitors may use 6 bits or 8 bits per color per pixel. This is old information and I'm not sure if 6 bit technology monitors are still being sold. The 6 bit technology results in noticable false edges ("stair stepping" in brightness or color) in smooth subtle changes in colors, such as backgrounds in videos or games. The LCD makers normally do not reveal this information in their specifications. Sometimes it's implied by the number of colors which should be 16.7 million on a 8-bit technology screen. Another issue is contrast ratio, which may include changing the brightness of the background light as opposed to the range of opacity of the actual pixel technology.

I still have 2 CRT monitors (20" and 18" viewable) that I plan to keep using until they stop working or until OLED monitors are reasonably priced (the early ones will be expensive). Their image quality is better than current LCD based monitors.
 
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  • #3
fluidistic
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First of all thanks for your lengthy reply.
So called "LED" monitors are LCD monitros that use LED's around the perimeter or in the backplane to allow sections of the screen to be lighted at different levels.
Ok, good to know.

True "LED" monitors will be OLED (organic LED, where organic is a chemical reference, not that the technology is based on some earth friendly technology). Currently these are used on the Samsung Galaxy S (smart phone), some small screens on specialized devices, and Sony makes a very expensive tiny TV based on OLED's. These should start show up as mainstream devices in 1 1/2 to 2 years.

http://en.wikipedia.org/wiki/Organic_light-emitting_diode
Ok. I had read that OLED screens lifespan is somewhere near 5 years compared to 10-15 years for the most used LCD. They will probably improve the lifespan of OLED but as of now I'd go for a LED and not OLED.
On a CRT monitor, the phosphors on the screen are designed to diminish in brightness in a short period of time (called persistance). This allows for quick motion of the images, but requires a corresponding refresh rate to avoid the dimming of the phosphors to appear as a flickering screen. Usually they're designed to look good at 75hz to 85hz. As a bit of trivia, and a extreme example, IBM made a monochromatic (green) display 3270 monitor where the phosphors had a persistance of over 1 second. It was great for producing very sharp text (since it could use a very thin electron beam and still be bright), but any motion, like scrolling, would look like a terrible blur until 1 second after the motion stopped. It was mostly used in data entry environments (like banks) where a fixed form was displayed, and the user filled in the empty fields.

Getting back to your question about refresh rates on digital monitors (LCD, Plasma, OLED), the pixels remain at a fixed brightness during each frame, quickly changing in brightness on each frame. You may be able to get response rate time for the pixels in the specification (usually the time it takes to make a 50% range change, a 100 % change is rarely specified). Contrast is limited by the range of blockage of light by the technology, generally an issue for dark scenes on LCD based televisions. To improve the quality of fast motion images, some digital monitors can refresh at 120 hz. However this can be an issue for some video cards, like the ATI HD5000 series cards, which have a max rate of 85hz, and due to some bug, are forced to 60 hz if resolution is 16x9 ratio.

LCD monitors may use 6 bits or 8 bits per color per pixel. This is old information and I'm not sure if 6 bit technology monitors are still being sold. The 6 bit technology results in noticable false edges ("stair stepping" in brightness or color) in smooth subtle changes in colors, such as backgrounds in videos or games. The LCD makers normally do not reveal this information in their specifications. Sometimes it's implied by the number of colors which should be 16.7 million on a 8-bit technology screen. Another issue is contrast ratio, which may include changing the brightness of the background light as opposed to the range of opacity of the actual pixel technology.
My graphic card is a Geforce. About the refresh time of LCD monitors, I'm guessing that 60 Hz shouldn't tire the eyes? As opposed to CRT monitos.
I still have 2 CRT monitors (20" and 18" viewable) that I plan to keep using until they stop working or until OLED monitors are reasonably priced (the early ones will be expensive). Their image quality is better than current LCD based monitors.
 
  • #4
rcgldr
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About the refresh time of LCD monitors, I'm guessing that 60 Hz shouldn't tire the eyes?
On a LCD monitor, the brightness of each pixel remains constant between frames, while it diminshes over time on the CRT (related to it's persistance). The CRT needs a refresh rate that corresponds to the persitance to minimize flicker effect.

On a LCD monitor at 60hz, the screen updates once every 16.7 milliseconds, if the transition time for the LCD pixels takes a significant amount of ths this 16.7 milliseconds, then you can see noticable effects if there is fast motion on images. I doubt this is an issue anymore on current LCD monitors, but I haven't researched this in a very long time. You can buy 120hz LCD computer monitors now, provided your video card supports this.
 
  • #5
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  • #6
fluidistic
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On a LCD monitor, the brightness of each pixel remains constant between frames, while it diminshes over time on the CRT (related to it's persistance). The CRT needs a refresh rate that corresponds to the persitance to minimize flicker effect.

On a LCD monitor at 60hz, the screen updates once every 16.7 milliseconds, if the transition time for the LCD pixels takes a significant amount of ths this 16.7 milliseconds, then you can see noticable effects if there is fast motion on images. I doubt this is an issue anymore on current LCD monitors, but I haven't researched this in a very long time. You can buy 120hz LCD computer monitors now, provided your video card supports this.
Ok thank you I understand. I don't really care if I see a "cut" image if I'm watching a movie or if I'm playing a fast video game, as long as my eyes aren't tired like with a 60 Hz CRT monitor.
$600 for a 24" LED monitor is stupidly expensive. Do most places ship to Argentina?

Here's a 24" LED Asus thats currently under $200
http://www.newegg.com/Product/Product.aspx?Item=N82E16824236102&cm_re=24"_LED-_-24-236-102-_-Product

I don't know if they ship to Argentina but I'm sure some online stores do.
Probably some stores do. The problem is that if I'm that lucky guy who does receive what I bought, I'll have to pay a ridiculous tax for the customers. By ridiculous I mean over 50% of the price of what I bought, as a minimum. So a 200 dollars monitor will cost me at least 300 dollars, considering I do receive it which isn't a given at all.
People working in customers here steal anything they like either for their family or to sell items to their friends at a reduced price.
I once bought a book on amazon (around 17 dollars) and the customers didn't want to give it to me if I didn't pay a 50% tax. I had to pay to get my book out of their hands. Later I read on the Internet that they can't tax books so I was pissed off. They don't respect the laws. When I was in the customers, I had seen a "poor" family waiting for a box coming from Florida, that their relatives in the US had sent them. It contained mostly food and products of the US that you can't find in Argentina. I think the value of the box was around 200 dollars and the customers wanted 100 dollars from the Argentinian family, in order to give it to them. They couldn't afford it so the customers were left with a big box. Also the police was in the same building and seems to work with the customers so that you can't complain.
I better not even try to buy something expensive on the internet. Too much stress.
 
  • #7
fluidistic
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I finally opted for the cheapest LED monitor I found, a 19 inches. I watched a movie with it yesterday night and watched some photos.
I do not have my eyes getting tired with the refresh rate (60 Hz) like I have with a CRT monitor. The resolution is much better than with my CRT monitor (85Hz), my screen bigger and the colors now are so awesome to my eyes I feel like I'd eat my screen. :biggrin:
The model is an LG Flatron E1940, it costed me 1060 pesos so around 265 dollars. Much cheaper than the 22-24 inches other monitor I could have bought.
I see no downsides as of now. I hope it will continue like that.
 
  • #8
Chronos
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I think you will be pleased with the compromise. LG is among the very best in picture quality. I had my mind made up to buy a different make until I went to the store and saw all of them in action side by side. I was immediately drawn to the LG monitor - a make I had not even heard of at the time. The picture quality stood out like a snow ball in a coal bin. A 19" is a big step up from a 17" monitor. Sure, a 22 or 24" would be nice, but not nice enough to justify the price difference. You saved enough to buy a very nice video card, if desired.
 

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