Let's Talk Panel Technologies

We've already given a brief rundown of TN panels and what they offer, but let's expand that to include the other three panel technologies. Here's the breakdown:

LCD Panel Technology Comparison
Panel Type IPS MVA PVA TN
Viewing Angles Excellent Excellent Excellent Okay Horizontal; Poor Vertical
Color Quality Usually Excellent Good to Very Good Usually Excellent Usually Good
Contrast Ratio >500:1 >500:1 >500:1 Usually >500:1
Color Gamut Depends on Backlight Depends on Backlight Depends on Backlight Depends on Backlight
Processing Lag 0ms (Usually?) 0-3ms 17-50ms 0-2ms
Response Time 6ms GTG 6ms GTG 6ms GTG Typically 2ms GTG
Cost Very High Very High? High to Very High Low to Medium

There are many similarities between IPS, MVA, and PVA - and note that these are now usually "Super" IPS/PVA or "Advanced" MVA. There are a few variants within the base panel type (i.e. E-IPS, H-IPS, and S-IPS), but the patterns generally remain true. Even TN panels have several areas that often overlap with the other techs. Let's look at the various areas in detail.

Starting with contrast ratios and color gamuts, modern LCDs have now reached the point where all panels will generally achieve a greater than 500:1 contrast ratio. Do not confuse this with "dynamic" contrast ratios, where the backlight can vary in intensity to help produce darker blacks and brighter whites at the cost of color accuracy - and it's also impossible to have bright whites and dark blacks concurrently, unless you have zoned backlighting, as current panels run the backlight at a uniform level for the entire display. Backlights also affect color gamut, with the key aspect being how much of the standard color spectrum the backlighting creates. Anything over 100% of Adobe RGB 1998 is overkill, and for most users even 82% of Adobe RGB 1998 (100% NTSC) is sufficient.

The other areas show more differentiation. Viewing angles greatly favor anything other than TN. It's worth noting that while vertical viewing angles often aren't as important as horizontal angles, if you want a display that can run in portrait mode you will definitely want to avoid TN panels (since in portrait mode the poor vertical viewing angles become horizontal angles). Manufacturers are also very generous in how they determine viewing angles, as they only require the display to maintain a 10:1 contrast ratio to qualify as "viewable". Realistically, we would say TN panels have a vertical viewing range of about 30° (15° up/down) before you notice severe image quality changes (i.e. from above the display becomes washed out, and from below it becomes very dark). Horizontal viewing angles on TN panels are probably closer to 60°, or even 90° if you're not super demanding. Compare that to the claimed 160° vertical/170° horizontal and you'll realize how inflated this spec has become with the target 10:1 contrast ration. In contrast, IPS/MVA/PVA all manage a fairly consistent 120° viewing angle in both vertical and horizontal alignments - possibly more if you don't mind the trapezoidal distortion caused by viewing from oblique angles. These displays advertise 176 or 178° viewing angles.

Color quality is also generally better on everything that's not TN, although here the (only) MVA panel we've tested seems to fall a bit short. When combined with viewing angles and the distortion that can cause to colors on TN panels, we'd stick with one of the other technologies if you want to get accurate color. In truth, this is mostly important for imaging professionals, as your eyes and brain will compensate to the point where you usually won't notice the difference. TN panels can also perform well in color accuracy, but they frequently do not because the manufacturers don't feel that's the target market - and in fact many displays have poor color accuracy by default because a lot of people prefer saturated colors. Also note that TN panels do not natively reproduce 8-bit color spectrums, relying instead on dithering and interpolation (switching rapidly between the two closest gray levels) to expand their 6-bit panels into pseudo-8-bit displays. This often shows up in color accuracy testing on TN displays with one or two colors having a high delta E while the rest are very close to ideal.

Pixel response times are another bloated statistic, with claimed response times of as low as 1ms for some TN panels and most now stating 2ms GTG (gray to gray). In theory, that would mean refresh rates of up to 500 Hz would be possible with no image persistence between frames. While no LCD currently available offers a refresh rate higher than 120Hz - and even those are relatively rare, only recently showing up with NVIDIA's 3D Vision technology - we still see image persistence on every LCD we've tested. That's not to say TN isn't a bit faster, but the difference is small enough that most users won't notice; either the response time will be "slow" on any LCD (relative to a CRT), or else it will be fast enough that you won't care.

Processing lag is potentially related to pixel response time. We don't know for sure if the lag comes after the crystal matrix receives a new voltage or if it comes before the voltage change, but we do know that of the tested panel technologies currently available, PVA seems to suffer the worst in this area by far. We only have one reference point on MVA panels, but we've read other reviews that support the idea that MVA response times are significantly better than on PVA. Processing lag can also come from hardware scalers used to support other resolutions, the prime example being Dell's 3008WFP. Even at native resolution, that display reportedly has anywhere from 10ms to 50ms of processing lag (depending on the revision that was tested). We have not seen any similar issues with other panels, most likely because scalers for lower resolutions have been around for quite a while and have been tweaked for optimal performance.

We also haven't tested any IPS panels outside of 30" LCDs, so we don't know for sure how IPS fares at other resolutions. Given 30" panels command a price premium, they may perform better overall than the smaller IPS displays; however, we believe IPS panels inherently process images as fast as any other LCD technology. Finally, it's worth noting that we have not been able to compare any LCD panel to a CRT for processing lag - we don't have access to any good CRTs anymore for comparison. Anecdotal evidence suggests that the best LCDs may still introduce a 15-30ms lag relative to a CRT. For better or worse, LCDs are here to stay and CRTs are a dying breed, so we'll constrain processing lag comparisons to LCDs and other newer panel technologies (i.e. OLED, SED, plasma, etc.)

Finally, we have to put all of this into perspective by introducing price into the equation. TN panel LCDs are by far the cheapest, often costing half as much as the same size display with an IPS/MVA/PVA panel. Since the non-TN displays do cater more towards professionals, some of the price difference may be artificial, but TN panels are still the least expensive option. They are also the oldest LCD technology, having been around since the dawn of LCDs. As much as you might want a high quality IPS display, when it comes down to a choice between a $400 22" IPS display or a $175 TN display, it's no surprise that a high percentage of people go with the inexpensive TN option.

So which panel technology is "best"? Clearly, it depends on many factors including pricing. Without price, I'd personally take an IPS display over any of the others, but again I may be biased by having only used 30" IPS panels. Many LCD HDTVs also use IPS panels, and given the recent growth in the HDTV market we'd expect there to be a few more improvements in the base technology. Like other displays, however, many HDTVs are now beginning to ship with TN panels, so if you're thinking about getting a new HDTV you'll definitely want to exercise care in what you buy.

Index A Closer Look at the BenQ FP241VW
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  • TA152H - Saturday, June 20, 2009 - link

    Even back 20 years ago, only a certain amount of companies made shadow masks too. Nanao did not make their own, but, yet, their screens were the best. It's not as simple as you make it sound.

    It's actually possible that NEC might make a better monitor in some instance, although I've never seen it, but, by and large, Eizo is much better. You know when you're looking at an Eizo.

    The picture quality is much better than NEC, or anyone else. I'll say this though, I have had uneven reliability with Eizo. Some monitors have been fine, and but more than there should be died quickly or had intermittent problems they should not have. This happens with all monitors, of course, but, in my small sample set, Eizo monitors have had more problems than others, but a small degree.

    Clearly, all that money is put into picture quality, not reliability.
    Reply
  • darklight0tr - Wednesday, June 17, 2009 - link

    Expensive != Quality and Eizo is proof of this.

    Our internal graphics department recently moved to 24" Eizo monitors at $1700 a pop and HATE them. They are inconsistent across the display, and are no better than the standard DELLs we use for the rest of the environment. They had high expectations for those displays and were really let down and the Eizo rep was no help at all. Its funny how communication diminished as soon as the sale was completed.

    What a waste of money.
    Reply
  • TA152H - Saturday, June 20, 2009 - link

    It's funny, because two people where I work got two Eizo's, and everyone wants them, and comments on them.

    Even on independent reviews, when they actually do get reviewed, they always are rated extremely highly, except for price. I don't know why your experience would be so much different, but, it sounds like you guys are either stupid (for not looking at the monitors first before buying a bunch), or it's made up.

    Probably the latter, since no one would buy a monitor that was really expensive without seeing it and judging it first.
    Reply
  • darklight0tr - Monday, June 22, 2009 - link

    Wow, a whole two people. What a great example you have there.

    We have a whole department with them (almost 20 monitors) and while they work okay, most of them don't live up to the price tag. As I said, the colors aren't consistent across the display, even after calibration (yeah, us stupid people actually know how to do that). This happens with pretty much every one we have. We didn't buy them sight unseen either, which would have been pretty moronic. I think it is the backlight that causes many of the issues, which is unfortunate. I hope LED backlight displays help with this problem.

    Who cares if they are reviewed well? I have them here in person and they don't live up to the price OR the reviews.

    Calling me stupid, how mature. How about not judging me based on your own limited experience?
    Reply
  • JarredWalton - Wednesday, June 17, 2009 - link

    See, that's the problem: server CPUs start out as super fast but the tech makes its way to consumer products. The same thing has happened with GPUs, HDDs, RAM, etc. to varying degrees - it's all substantially cheaper now and performance has improved. But LCDs? Well, Eizo makes high quality LCDs, certainly, but they cost an arm and a leg. The cheapest 24" Eizo (taking a quick look) is over $800, with other models costing $1500 or more. They may be the best displays on the market, but what I want is to see that quality make its way into $500 LCDs. Reply
  • Spoelie - Wednesday, June 17, 2009 - link

    http://translate.google.com/translate?prev=hp&...">http://translate.google.com/translate?p...mp;sl=nl...

    Launched in japan just yesterday with a $500 pricetag...

    Now if only they would sell it abroad as well with a similar pricetag. And we need a review, it's "VA" technology but which one?
    Reply
  • Mastakilla - Wednesday, June 17, 2009 - link

    Eizo is not at all that good for it's price

    For a similar price you get a muuuuuuch better NEC monitor (check out the xx90 series)
    Reply
  • Griswold - Wednesday, June 17, 2009 - link

    Not going to happen. Well, maybe eventually the cheapos arrive at todays quality of Eizo, but then Eizo would have moved beyond that again. :P

    Quality and spending a few hundred bucks just doesnt go together. Buy Eizo and be happy for many, many years - not only due to the 5 years on-site warranty (not that I've ever had to make use of it, though..)
    Reply
  • HexiumVII - Wednesday, June 17, 2009 - link

    I've been using of those old Soyo 24" with the MVA I got for $250 a few years back, its great, has all the advantages of MVA and color is very accurate with my spyder. At school we have 24" iMacs and the screen is just friggin amazing. It's just so much better than everything else out there. A lot of it has to do with the glossy screen. So here's to a 24" 16:10 screen with gloss for a reasonable price one day. Reply
  • marraco - Wednesday, June 17, 2009 - link

    I got crazy trying to play Crisys 2 at the morning on a glossy monitor. There was no way to see clearly the image without reflections. There was no way to accommodate the monitor to reduce reflex.
    glossy is an absolute crap. I hate it from gut.
    Reply

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