Not All LCD Panels Are Created Equal

Jeff Atwood -

When I purchased my last set of LCD monitors, I didn't fully understand that not all LCD panels are created equal. There are three distinct families of LCD display technology, each with their own tradeoffs and peculiarities. Before you buy a new LCD display, you should take note of what kind of panel technology you're investing in.

Color Reproduction Viewing Angle Response Time Price Quirks
*-IPS
In Plane Switching		 Excellent Excellent Good Expensive Slight color tinges may be visible at an angle.
*VA
Vertical Alignment		 Good Good Average Reasonable Colors shift when viewed at an angle.
TN
Twisted Nematic		 Average Average Excellent Inexpensive Limited to 6-bit color; restricted vertical viewing angles.

Most panels these days are TN, which isn't much of a surprise; if a consumer has the choice between a 22" or 24" display at the same price, they're naturally going to go with the larger one. Although TN displays can be quite good, they all suffer to some degree from the genetic defects of their TN family lineage.

Right now, one of my monitors is PVA, and the other two are TN. The color reproduction is slightly more pleasing on the PVA monitor, but the TN is in the ballpark. I'm only able to tell because the monitors are literally right next to each other. What I do notice in regular use on my TN displays, however, is their incredibly limited vertical view angle. I'm no graphics designer, but even I can see that colors vary quite noticeably in intensity from top-to-bottom on my TN display. You have to keep your head perfectly aligned in the tiny "sweet spot" to see consistent vertical color on these displays. Horizontally, it's fine, but vertically, it is far too sensitive.

Unfortunately, the vast majority of LCDs on the market now are TN. You can opt to pay a little bit more for one of the few models with *VA -- if there are any available in the size you want. *-IPS is widely considered the best all around LCD display technology, but it is rapidly being pushed into the vertical "pro" graphics designer market due to the big jump in price. It's usually not an option, unless you're willing to pay more than twice as much for a monitor.

But even within the TN and *VA families, there are new improvements and variants being introduced all the time. For example, LED backlighting, which is just now catching on for laptops, should eventually trickle down to the humble TN display. That one upgrade will allow it to reproduce all 100% of the NTSC color gamut for the first time. There's a more detailed chart at LCD Resource that illustrates how the various LCD display technologies have evolved over time. I've adapted it here in simple HTML:

Bright Black Level Resp Time Color
Depth		 Gamma Sat View Angle (H) View Angle (V) Input Lag Cost
TN                    
20/22" TN                    
P-MVA                    
20"+ P-MVA                    
PVA                    
20"+ PVA                    
S-PVA                    
S-IPS                    
20" S-IPS                    
AS-IPS                    
A-TW-IPS                    

Don't get discouraged, though. Modern, inexpensive TN based LCDs can still perform quite well, as you can see in this review of the Samsung 245BW. The main downside is-- you guessed it-- the severely limited vertical viewing angles.

The next time you set out to buy a LCD, be informed about the underlying display technology you're getting. If you're in the market, I recommend paging through the excellent LCD Monitor Buying guide at X-bit Labs, which covers that crucial aspect, and much more.