Your Guide To LCD Television » Technology

Type of LCD TV Panel Technology

admin — Sun, 25 Jul 2010 15:25:43 +0000

Today LCD TV dominant display technology, compare to Plasma, CRT, and etc. For LCD (liquid crystal display), there are many different type of panel technologies used for production of LCD televisions and LCD monitors. LCD panel technology not limit by LED LCD TV or CCFL LCD TV, it is independent from the backlighting technology and it do contribute to contract ratio, brightness, switching speed (or respond time), viewing angle and color depth. The budget panel technology is TN panel, while the expensive panel technology target high-end market and professional quality are S-IPS and S-PVA panels. The average consumer usually has no idea what panel technology is used in their LCD TV, simply because the panel type is rarely listed by the manufacturer in the LCD TV specifications. Many buyers buy LCD TV based on price and size. Price should be a factor, but you should still know the advantages and disadvantages of the different LCD panel types and be able to identify them before you decide which LCD TV (model and brand) to purchase.

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:

TN – Twisted Nematic (cheaper to produce and biggest market share)
IPS – In Plane Switching
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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TV Technology Overview

admin — Sat, 13 Dec 2008 03:17:13 +0000

Rear Projection TV

Rear-projection television
Rear-projection HDTVs still offer the biggest screen for your buck, although falling prices among big-screen plasmas – 58 inches and up – are forcing RPTV makers to cut prices on their own. It’s pretty obvious, in fact, that eventually RPTVs will go the way of the dodo as flat-panel HDTVs take over completely, but we’re still a couple years away from that. Rear-projection sets start at a sizeable 50 inches and go up from there. RPTV utilizes digital light projection or DLP technology that is driven by a lamp that bounces light through an assembly that produces color and then projects it onto the big screen. Upside for Rear-projection television is less-expensive at very large screen sizes than plasma or LCD TV, and able to produce good black-level performance on certain best models. The only downside is the lamp requires periodic replacement, thicker and bulkier than flat-panels, rainbow effects (on the projected light beam), less impressive off-angle performance than plasma and LCD televisions.

The lamps inside these sets, which cost $200 and more, must be replaced every 3,000 to 6,000 hours (around 2 years operating with ~8 hours per day), depending on conditions of use and users can replace most lamp assemblies on their own. The lamps take from 20 seconds to a minute to warm up and cool down. In the warm-up phase, the image is either dim or completely dark. DLP is getting cheaper as flat panels get bigger and reduce price. Currently, RPTVs still the best technology to deliver huge image with great value.

Plasma television
With prices starting about $700 for the least expensive models, a coveted plasma TV is within reach of most shoppers. But now that you can get a 42-inch LCD for a similar chunk of change, plasma TVs have to depend on factors other than price to remain competitive. One area where plasma still reigns, however, is in very large screen sizes. Today’s 50-inch plasmas – the plasma TV sweet spot – are still less expensive than similarly sized LCDs, and in even larger screen sizes the gap widens considerably. That said, big-screen plasmas are still a solid chunk of change more than rear-projection sets. The pros of plasma TV is thickness of around 3 inches, with very good home-theater image quality, wide viewing angle and superior motion resolution. However, for green concern buyers, they might complaint it less energy-efficient than LCD TV. Plasma TV also slight potential for burn-in, and sometimes lower resolution than similarly sized LCD TV.

Flat-panel TV In Living Room

LCD television
LCDs will generally have a higher resolution than plasmas of the same size. Larger LCDs, as big as 65 inches, remain more expensive than plasma and rear-projection models. In the popular 40 to 42 inch size range, LCD prices have dropped. As of fall 2008, flat-panel LCDs in this size range can be had for as little as $750, just a bit more than plasmas. The upside of LCD TV is available in a range of sizes, and matte screens generally reflect less light. LCD TV theoretically immune to burn-in. Low-end LCD TVs’ image quality generally not as good as on plasma models, and relatively narrow viewing angle compare to plasma TV.

Direct-view television
This is the television a majority of people have. Direct-view or tube TVs can be found in sizes up to 36 inches (diagonal), and as their screen sizes increase, so do their heft and depth. The largest models in the mid-30-inch range can weigh nearly 200 pounds and measure two feet deep. Because of size and weight issues, it doesn’t pay for companies to make larger tube TVs; they simply aren’t practical. Upside is relatively inexpensive. Downside is bulky and heavy; limited screen size; lower resolution; usually incapable of displaying HDTV sources, and rarely PC-compatible (but you still can use S-Video to display your computer image on it, provided your video-card has S-Video output port). Tube TVs are becoming uncommon in stores, but this technology still has a few years left before it dies completely.

HDTV resolutions
Resolution, or picture detail, is the main reason why HDTV look so good. The standard-definition programming most of us watch today has at most 480 visible lines of detail, whereas HDTV has as many as 1,080. HDTV looks sharper and clearer than regular TV by a wide margin, especially on big-screen televisions. It actually comes in two different resolutions, called 1080i and 720p. One is not necessarily better than the other; 1080i has more lines and pixels, but 720p delivers a smoother image that stays sharper during motion. Another format is also becoming better known: 1080p, which combines the superior resolution of 1080i with the progressive-scan smoothness of 720p. True 1080p content is scarce outside of Blu-ray, HD-DVD and the latest video games and none of the major networks has announced 1080p broadcasts.

How important is resolution?
Not as important as you might think. Once you get to high-definition, most people are satisfied with the sharpness of the picture. All other things being equal, HDTV looks more or less spectacular on just about any high-def television regardless of its size or the HDTV signal’s resolution itself.

What Is “HD Ready”

admin — Wed, 15 Oct 2008 14:15:28 +0000

Walk into Best Buy, you would see a lot of televisions put a sticker with label of “HD Ready” or “Full HD” on the corner of the television frame. What is the real meaning of “HD Ready” and what kind requirements the product need to meet to classify as “HD Ready”?

HD ready

Requirements For The Logo “HD Ready”

The EICTA minimum requirements for display devices to label with “HD Ready” are neutral towards the technology used (plasma, LCD, DLP, DLA, LCoS, CRT, and etc) as well as the implementation, thereof flat panel, rear projection, front projection, direct view, and etc can be classify as HD Ready. A display device has to cover the following requirements to be awarded the logo “HD ready”:

Display – The minimum native resolution of the display or display engine is 720 physical lines in wide aspect ratio.
Video Interfaces – The display device accepts HD input via analogue YPbPr1 and DVI or HDMI. For display signal to be classify as HD capable input, it must accept the following HD video formats: 1280×720 @ 50 Hz and 60 Hz progressive (720p), 1920×1080 @ 50 Hz and 60 Hz interlaced (1080i). For digital HD input (DVI or HDMI), it must supports content protection technology (HDCP).