The digital flat panel monitors are also called "soft" screens, since their images seems to have a "softer" quality than those from traditional CRT monitors. The image does not flicker thus causing less eye strain.
People, like myself, who have become accustomed to these soft images will not return to the traditional monitors. I cannot express this with enough emphasis: The flat display is the best monitor available. It is so good to your eyes!
Modern research has shown that a steadily illuminated screen image is a very important element in a good work environment. The eye responds to all light impressions, and the brain interprets all light impressions continually. When a mediocre monitor flickers, the brain will continually receive superfluous light impressions "noise" to sort out. Thus the brain works permanent overtime interpreting the screen flicker. No wonder that people get tired from watching their monitors.
At the same time the LCD screen is by far the most environmentally safe product. These flat screens emit zero radiation, and they consume significantly less power than the traditional monitors. Another reason to expect LCD screens to become the monitors of the future.
No refresh rate
A big advantage in the LCD screen is that it does not flicker. Traditional CRT monitors flicker all the time which is not ideal. Of course the best CRT monitors have a high refresh rate (85 Hz or more), which provides a very stable image with no noticeable flicker. But the LCD screen does not flicker at all (when digitally connected). They have a refresh rate of 0 Hz!
Please notice that looking at LCD displays, you may read information like:
* Pixel Frequency 65MHz
* Horizontal 30 ~ 50KHz
* Vertical: 55 ~ 70Hz
This indicates that there is a refresh rate. There is, but it is only working when the screen image is changing. So if you move a window across the screen, the changes will be updated with a refresh rate of 60 Hz or what ever you choose.
To many users this does not really matter; using Office programs, most of the time the screen image does not change, hence it does not flicker. Obviously it is a problem if you expect to use your flat panel monitor to show full motion videos or games.
The digital interface
The most important thing about the flat panel monitor is that it is connected to a digital graphics port. Unfortunately, this is not always the case.
Back in 1997, when I got my first flat panel monitor (the Siemens 3501T mentioned above) it was only available with a (total proprietary) digital graphics adapter. This was a 1st generation flat panel monitor. Later the manufactures found out to add an analog port in the displays. This way people could buy a flat panel monitor and reuse their exixting graphics adapter. It is a marketing stunt, which should not be followed!
The only way to benefit from a flat panel monitor is to feed it digitally.
In spring 2001 I bought a new flat panel monitor; it is a Dell model 1701FP. A nice 17.3" monitor, which I paid around $900 for (the price have decreased later). The monitor holds both an analog (VGA-) port and a digital port (DVI).
A 17.3" flat panel monitor has a visible area much bigger than that from a traditional 17" CRT monitor - you can compare it to a 19" CRT. The 17.3 inches is the visible diameter.
I was told, that it should work fine using the analog port with my existing Matrox G400 graphics controller. The manual emphased that one should use the 60Hz mode. I installed the hardware, and it worked fine. Only the image was terrible! It was flickering and very unsharp, kind of "dirty".
The weird thing is, that the Dell manual holds almost nothing on these issues. But through testing we found out that the 75 Hz analog mode was the best possible. But it was not satisfactory, not at all. Having paid quite a lot of money, we desided to go for a digital graphigs controller. We found an ATI Radeon VE, which turned out to be a great card at a reasonable price:
From the box, the product seems to be aimed gamers. To those I am sure, that the RADEON chipset and the 32 MB of DDR RAM is fine. To us, the very important issue was, that there is a DVI connector on the board:
With the DVI connector in use, the DELL flat panel monitor works absolutely perfectly. Thinking about it, it is incredible, that the company does not tell this in the manual. With digital interface the image is extremely sharp and completely flicker free.
A flat panel monitor is digital by nature. There is no analog electronics included, and that is the big advantage of this technology. Hence, the monitor should not be connected through an analog interface. In fact, using the analog interface, you get to conversions, which both add noise to the final image. First the graphics adapter has to convert the digital data of the PC to analog electronical signals. Then these analog signals have to be converted back til digital information to feed the display.
Using the digital interface, each pixel consists of three transistors, which each is mapped to the corresponding memory cell holding the image info. A purely digital to digital transmission with no electronical noise involved - that is the way to produce a stunning image!
It is difficult to produce a flat panel display without flaws. Most panels sold have a few defect pixels, where one or more transistors are gone.
The bigger the panel gets, the more flaws you find (due to the increasing number of transistors). This helps keeping up the prices - the manufactures have to throw away a large percantage of the production - you cannot repair flawed pixels.
All vendors have some kind of quality policy in this area. Some only accept up to 3 or 5 pixel flaws per panel. Others accept up to 15, if they are not situated in the middle of the display. When you buy a flat panel display you should make sure that you can return it if the number of pixel-flaws is to big. This can be hard to achieve.
In the summer 2001, a German survey showed that some vendors take advantage of the consumers ignorance in this area. More than 30% of the flat panel monitors were of second range quality and should not have been brought to the shops. Obviously it has been tempting to some companies to sell some of the displays, which should have been dismissed.
Using a LCD display, you should remember to install the Windows screen saver. I use "Black screen" after 5 minutes. Like in the "old days", the monitor may get damaged from longer periods of showing the same image.
Yes, DVI is DVI. It is funny that they charge more for DV output, because you are bypassing RAMDAC
chip completely in straight Digital to Digital. (I'm sure you've seen those Geforce blurbs on their high
speed 350MHZ RAMDAC)
In straight thru digital, the true quality of the card GPU is evident.
What you see is what you get.
And don't buy a digital monitor online, or new in the box. Make them fire it up in the store and teach
yourself to spot dead pixels. I cannot bear even one dead pixel.
Edit:I built an "integrated" system for a friends business, and told him LCDs are better, so, on his own, he
saw the Viewsonic VG150 on sale at CompUSA and bought it. The mobo was the Abit SA6R, which has a
very mediocre on board graphics chip. Much to my surprise, we hooked it up, loaded the given drivers,
and it played quite decently, thank you. I simply didn't have the heart to tell him "the rest of the story"
(heh heh).
LCD Pixel Criteria Guidelines
Due to current manufacturing methods of LCD display panels, a certain number of sub-pixel anomalies (a pixel stuck on or off) are acceptable. Because the manufacturing yield of perfect LCD Displays are very low, displays may have some sub-pixels that are either always on or always off. The cost of accepting only perfect displays could nearly double the price of a and LCD Display. This is true of all products using LCD technology, not specific to one manufacturer. If the industry attempted to set a zero standard, the current manufacturing yield would be so low that the cost of an LCD display would be many times higher than it is today. Luckily, most customers and applications are tolerant of a low level of non-performing pixels and prefer the lower cost that the existing standards allow.
It is advised that if you think your LCD screen contains an excessively high number of pixel anomalies, you can contact tech support to arrange an evaluation. However, you should be aware that we will not replace a screen with just one or a small number of dead pixels.
Pixel Guidelines:
Each LCD Manufacturer 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 10 non-performing pixels would equate to an extremely small 0.00025 percent of the total sub-pixels.
(1280 Horizontal Pixels) * (1024 Vertical Pixels) * (3 sub-pixels per pixel) = 3,932,160 sub-pixels
[(10 non-performing pixels) / (3,932,160 sub-pixels)] * 100% = 0.00025%
To ensure the highest performing displays, the manufacturer sets limits as to the allowable number of pixel anomalies. The manufacturer has adopted the following pixel criteria to supplement our existing limited warranty. This policy applies to all the manufacturer LCD displays during the warranty period.
The manufacturer sets limits on 14" - 15" LCD?s at 5 bright sub-pixels, 5 dark sub-pixels, or a combination of 8.
The manufacturer sets limits on 17" - 18" LCD?s at 8 bright sub-pixels, 8 dark sub-pixels, or a combination of 10.
the manufacturer sets limits on 20" & greater LCD?s at 10 bright sub-pixels, 10 dark sub-pixels, or a combination of 15.
*It is possible that any replacement display may also have some non-performing sub-pixels. This should be considered when requesting a warranty exchange.