In-Plane-Switching Technology

One item of LCD TV that manufacturers don’t usually make a big deal about happens to be the aspect of any display that seems to matter most is the panel technology. There are three general categories of panel technology:

1. TN – Twisted Nematic (cheaper to produce and biggest market share)
2. IPS – In Plane Switching
3. MVA / PVA – Multi-domain Vertical Alignment / Patterned Vertical Alignment

Opinions about which technology is actually best differ somewhat, but there’s no denying the fact that TN is substantially cheaper to produce whereas PVA and IPS are more expensive. Vast majority of LCD TVs (and monitors) today are once again using TN panels, largely because of the pricing advantage.

TN (Twisted Nematic) Panel Technology

TN (Twisted Nematic) panels are the most widely used panel type in the manufacture of LCD panels. TN panels are cheap and offer excellent response times. The response times of current TN panels range from 2ms to 5ms. However, color reproduction, viewing angles and contrast ratios of TN panels are the worst of any current LCD panel technology, particularly vertical viewing angles. Unlike most 8-bit IPS/VA based panels, TN is only 6-bit and unable to display the full 16.7 million colors available in 24-bit true color. Most TN panels are natively 6-bit panels that use dithering to approximate 8-bit color. Most people won’t notice the difference in color accuracy of TN panels. They can mimic the 16.7 million colors of 8-bit panels using a technique called dithering, but the results are unimpressive. TN panels dominate LCD TV market because they are very inexpensive and produce good enough display for most buyers.

IPS (In-Plane-Switching) Panel Technology – S-IPS/H-IPS

IPS (In Plane Switching) panels are generally considered the best overall LCD technology for image quality, color accuracy, good viewing angles, true 8-bit colors, but all this comes at a price. S-IPS (Super-IPS, Hitachi in 1998) panels offer the best viewing angles of any current LCD technology, with wide viewing angles up to 178 degrees. The response time of S-IPS is adequate, ranging from 6ms to 16ms. It responds time is only slightly slower than TN panels. Fast paced motion picture (sport game show) may suffer from motion blur or ghosting with S-IPS panels that have a response time higher than 8ms.

S-IPS panels can be identified by a slight purple hue on blacks when viewed from a wide angle. There are currently few manufacturers using S-IPS panels in comparison to the other panels types making choices limited and they often carry a premium price tag. H-IPS (Horizontal-IPS, NEC in 2007) is a newer variation of S-IPS with a different pixel structure that improves contrast ratios and lowers pixel pitch to provide better picture quality.

The famous LCD TV manufacturers based on IPS technology are LG-Philips, and IPS Alpha Technology (formed by Hitachi, Panasonic and Toshiba).

VA (Vertical Alignment) Panel Technology – MVA / PVA

VA (Vertical Alignment) technology such as S-PVA/MVA is middle of the road LCD panels. They offer better color reproduction and wider viewing angles than TN panels, but have slower response times. They are very similar to S-IPS on paper. They also offer large viewing angles and good color reproduction, though not as good as S-IPS. The response times are generally worse than TN or S-IPS panels.

PVA and IPS viewing angle comparison

VA panels have the advantage of higher contrast ratios compared to other panel types, which leads to better black levels. The biggest disadvantage of VA based panels is color shifting. Color shifting is when the image viewed from one angle changes or “shifts” when viewed from a slightly different angle, making various uneven brightness levels across the display. Color shifts also cause a loss of shadow detail in dark scenes when viewed directly from the center. VA panels are much easier to find compared to IPS because so many manufacturers use them. They offer better image quality than TN at lower price than IPS based panels.

MVA (Multi-domain Vertical Alignment) was originally developed in 1998 by Fujitsu as a compromise between TN and IPS. It achieved fast pixel response, wide viewing angles and high contrast at the cost of brightness and color reproduction. Modern MVA panels can offer wide viewing angles (second only to S-IPS technology), good black depth, good color reproduction and depth, and fast response times.

PVA (patterned vertical alignment) and S-PVA (super patterned vertical alignment) offers similar features to MVA, but boasts very high contrast ratios such as 3000:1. S-PVA panels all use at least true 8-bit color electronics and do not use any color simulation methods. S-PVA panels offered by Eizo (at least newer ones) use even 10-bit color internally, which enables gamma and other corrections without banding. PVA and S-PVA can offer good black depth, wide viewing angles and S-PVA can offer additionally fast response times thanks to modern RTC technologies.

Famous LCD TV manufacturers using S-PVA panels for their LCD TV are Samsung and Sony.

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Panasonic IPS-Alpha LCD Panel Technology

A quick overview of the panel technologies

Viewing angles on TN are substantially worse, particularly vertical viewing angles, and all TN LCD panels are natively 6-bit panels that use dithering to approximate 8-bit color. Most people won’t notice the difference in color accuracy, but imaging professionals would definitely prefer something better. The advantage of TN panels is that input lag is not a problem. Response times are usually lower on paper, but again it’s difficult to actually see the difference between a 2ms panel and a 6ms panel, especially when the display refreshes every 17ms (60 Hz refresh rate).

PVA and IPS are basically the exact opposite of TN: great viewing angles, very good color reproduction, and true 8-bit colors. However, pixel response times are a little lower (it’s not something that has ever bothered us). The big problem on the S-PVA panels are input lag, ranging from as low as 20ms up to nearly 50ms. However, S-IPS panels (example of S-IPS brand LCD TV is Panasonic Viera) don’t seem to have a problem with input lag.

Viewing Angle Comparison Chart Released By Sharp

A less common panel type is MVA, which in practice is similar to PVA but seems to perform better in regards to input lag. Color quality and other aspects are also good, but pricing and availability is a concern.

Frequently, the choice will come down to getting something larger with a cheaper TN panel versus getting a smaller LCD with a PVA/IPS panel. Even among the same panel technology, however, there are wide variations in quality. Most LCD panels are manufactured by one of only a few companies (Taiwan Chung Hwa Picture Tubes, Chi Mei Optoelectronics), but similar to processors these panels are “binned” based on quality. Bottom line, you get what you pay for! If you’re wondering why LCD A seems to have the same specifications as LCD B but costs significantly less, it’s very likely that the panel doesn’t meet the same quality standards. Color uniformity is one of the big differences between various LCD panels, with the best panels often ending up in displays that cost twice as much as LCDs that are otherwise equal in terms of specs.

LG Display - TrueMotion 480Hz

The scanning backlight from LG Display is a technology that enables a backlight to be repeatedly turned on and off to reduce motion blur. When combined with the company’s 240Hz technology, the display can refresh 480 images per second.

The display is claimed to have a 4ms response time, and uses a “scanning backlight” technology to leverage the company’s 240Hz Trumotion technology into an effective 480 images per second. Important details information like screen size and resolution not available at this moment. Due to no detail information, it might be kind of interpolation effects technology.
The Trumotion 480Hz LCD TV panel is to be launched in the second half of 2009.

What the different of LCD and Plasma technology?
Plasma and LCD panels may look similar, but the flat screen and thin profile is where the similarities end. Plasma screens, uses a matrix of tiny gas plasma cells charged by precise electrical voltages to create picture. While LCD screens, as it name suggests, liquid crystal display are liquid crystal sandwiches between two glass panel. Again, electrical charge voltage applied to varying the liquid crystals. Plasma TV have slightly edge over LCD in term of black color display, which mean better contrast and detail in dark-colored movie scenes. The LCD technology, light source from CCFL (Cold Cathode Fluorescent Light) or white LED (latest version) shines through crystals panel and glasses layer, hard to achieve perfect black color because there is alway some light leakage in between pixels. Manufacturer keep improving with new technology and manufacturing advancement from generation to generation. Apart from better contrast with better ability to show perfect black, plasma screens do have wider viewing angles than LCD screens. Viewing angle mean how far you can sit on either side of screen before the image of screen disappear.

Samsung LED backlight Full HD LCD TV

For LCD screen, some brightness and color shift happen when viewing angle is high (far from center of screen). Plasma screen have better viewing angle compare to LCD screen. Manufacturer are improving the lagging of LCD screen technology to catch up with Plasma screen technology, and steadily changing with more and better LCD screen technology entering the market, where now the viewing angles of some model of LCD screen is equal or better then plasma screen. Plasma produce brighter color too, compare to LCD screen due to light leakage on LCD between pixels that affecting its color saturation.

Advantages of Plasma over LCD technology
LCD screens tend to has blur images in fast moving scenes in action movie or sport due to slow switching time of crystals from black to white. While this was true for older generation LCD screens, new models have improve significantly and close the gap between these two technology. The lowest the switching time for LCD, the better the image quality in fast moving scenes. Currently there is some manufacturer claim their LCD TV switching time as low as 2ms, while typically 6ms switching time will provide good fast moving scenes. Another advantage of Plasma is low price for screen size larger than or equal to 42-inch. This has changed recently where LCDs’ price for screen size of above 42-inch are matching or even beating plasma in both resolution and price.

Advantages of LCD over Plasma technology
Apart from being price competitive, LCD has the edge over plasma in several other key areas. LCDs tend to have higher native resolution than plasmas of similar size, in layman term, it mean more pixels on same area of screen. LCDs also consume less power than plasma screens with estimated power saving of more than 30 percents. Except for greener for LCD technology, it weight lighter than similar sized plasma TV and making it more feasible to mount on wall. The lifespan of LCD TV out-perform plasma TV where plasma screen would lose half of their brightness after more than 20,000 hours of viewing. While almost all LCD TVs have lifespan of 60,000 hours or more. However, newer version of plasmas have bumped up that lifespan to between 30,000 and 60,000 hours. Plasma TV prone to screen burn effect if static image left display on screen too long and resulting the ghost of image burned in permanently to plasma screen. Newer plasma TV less susceptible to this with improved technology. LCD screen do not suffer from this due to the picture is display via changing crystals.

LCD or plasma the mainstream technology in market today?
Currently only 3 manufacturer continue to roll out new models of Plasma TV, there are Panasonic, Pioneer and Hitachi. For LCD TV, there are tones of manufacturer and the price had drop more than 15 percents year-on-year. If you look for better resolution, go for LCD TV. If you prefer big screen size with good image quality, but not on resolution, Plasma is the right choice for you. Today LCD TV manufacturer drive full HD (High Definition) as the selling point to fight Plasma TV, but now new version of Plasma TV do support 1080p high resolution. Despite the current HD buzz, the content available in 1080p is still very little and you are paying the premium price of Full-HD for future, not tmorrow.