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Are You Ready for Super Thin TVs the Thickness of Cardboard?

Updated
By Alfred Poor, dealnews contributor

thinnest HDTVsThere once was a time not too long ago, when consumers were so caught up in the massive difference between old-fashioned TVs (and even DLP types) and flat-screens, that they didn't even worry too much about how flat is flat.

Now, though, the race is on for manufacturers to make the biggest and thinnest TVs they possibly can. How much thinner can a flat screen really get? The answers are different for the two major types of flat screens — plasma and LCD — so here is the scoop.

Plasma
Plasma HDTVs have the advantage of being less expensive than most LCDs of equivalent size and features. One of the trade-offs for this lower price is that the image generally is not as bright, so you need to be able to control the room lighting to get an equivalent picture.

Plasma works much like a fluorescent light; you run an electrical current through a gas and it gives off invisible ultraviolet light. This hits chemical phosphors that glow red, green, or blue, depending on their chemical composition. These panels are relatively easy to build, and they can use low-quality glass for the front and back substrates.

For years, the plasma manufacturers used the same thickness for their glass, mostly through inertia. In recent years, they have discovered that they can use thinner sheets, which saves on material and shipping costs. This can only provide limited reductions in thickness, however. Much of the space is taken up by the cells that are coated with phosphors. If you make the panel thinner, then the cells get smaller. This means that there is less room for the phosphor, which means that less light is produced.

Increased efficiencies and smaller controlling electronics can help reduce the size of plasma panels, but at present they are still a few inches thick. Our most popular current plasma deal is the Panasonic VIERA 42" TC-P42S30 for $623 plus free shipping from 6th Avenue Electronics (with coupon code "AFL4COUPON"). Its width is 2.8", but that still can't match how thin LCD panels have become.

LCD
Unlike plasma panels, LCD panels do not produce any light on their own. The liquid crystal layer simply provides millions of tiny shutters that either transmit or block light. You need to put a very bright light behind the panel in order to produce an image that you can see. In fact, even when it is showing an all-white screen, as much as 95% of the light is absorbed by the panel, so the backlight has to be very bright.

Traditionally, this light came from fluorescent light tubes that snaked across the back of the panel. These are relatively inexpensive to make, but they contain mercury with is an environmentally hazardous material.

As a result, LCD display makers have turned to LEDs as a light source. They are highly efficient and very small, so they were initially adopted for use in mobile LCD devices such as cell phones and MP3 players. The cost of LEDs has dropped rapidly, however, and they have become much brighter. The first LED backlights for HDTVs simply replaced the fluorescent lamps behind the panel. This require lots of LEDs, but it made it possible to dim different regions of the screen to increase contrast and lower power consumption. Our most popular backlit LCD model listed at the moment is a 40" TCL Widescreen set for $400, that is less than 2" thick.

Improvements in light guides and diffusers to spread the light out made it possible to move the LEDs to the sides of the LCD panel. This meant that the backlight became an "edgelight," and LCD HDTVs became much thinner. Initially, the LEDs were placed along all four sides of the panel, but brighter LEDs and better light guides have allowed manufacturers to use LEDs on fewer sides. One recent top pick by our readers was a Toshiba 3D bundle for $1,500, that is 1.15" thick.

How far can this technology go? LG Electronics has demonstrated a 42-inch LCD HDTV that is just 2.6 mm thick. That is only as thick as a sheet of corrugated cardboard. This technology is not yet available commercially, but some products come very close to this. For example, the Samsung 9000 Series sets are less than a third of an inch thick, which is about three times as thick as the LG demonstration.

How Thin Can You Get?
Are we at the end of the line? Hardly! There are other technologies on the horizon that could result in even thinner television sets. LG has committed to starting a Gen 8 production line for OLED displays this year, which could be used to make panels as large as 55". OLED is an emissive technology — no backlight required — and it only needs one layer of glass as a substrate. As a result, the display panel could be as thin as a sheet of glass. And Corning can make high-quality glass that is as thin as 0.5 mm thick for Gen 8 panels (that's about 2 hundredths of an inch, or about half the thickness of a sheet of printer paper).

You'll probably have to wait a few years before these new technologies are affordable, but the dream of a large screen HDTV that you can roll up like a window shade is not out of the question in the next five or 10 years.


Alfred Poor, known on the web as the HDTV Professor, is an independent technology industry analyst and freelance writer based in Pennsylvania, specializing in PC-compatible microcomputer hardware and software products. He was a contributing editor to PC Magazine and Computer Shopper, and currently is a columnist at HDTV Magazine.
Please note that, although prices sometimes fluctuate or expire unexpectedly, all products and deals mentioned in this feature were available at the lowest total price we could find at the time of publication (unless otherwise specified).
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7 comments
Dealjones
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RobS
I'm afraid this bozo (Alfred Poor) knows very little about the technology he's describing. His description of plasma panels and why they cannot be made thinner (the glass they use) is so very, very wrong. The plasmas have dramatically different drive requirements (both voltage and current) that necessitates certain physical constructions...putting high voltage drivers with heatsinks directly behind the panel itself.

Shame on Dealnews for giving this idiot a forum.
uronacid
You clearly haven't used a decent plasma in the past 4-5 years. Plasma TVs are extremely reliable today and have improved in the areas you mentioned. 
drshuey
One problem with thinner TVs is that they don't have enough support.  The current 55" Sumsung D7000 has a tendency to warp because it is too thin.  There isn't enough plastic around it to keep it straight and level.
youthattack
The backlit LG model you listed at $1,699, the LW5600, is not backlit at all.  It is LED edge-lit with LED Plus, a basic from of local dimming using the edgelight.  it still can't compete with real LED-backlit sets.  LG's backlit sets using their new nano LED backlighting tech have not been release yet, and will be sure to cost more than $1,699.

On another note, "brightness" alone does not win the TV game, which this article seems to imply.  LCDs are brighter, will hold up better in bright lighting conditions, and don't suffer image retention.  Plasmas, on the other hand, give you much better dim-to-dark room performance - generally deeper blacks, MUCH better motion resolution, better shadow detail, better viewing angle, richer color performance (color does not get washed out by an always-on back or edge-light), and just about perfect uniformity across the entire image panel.  LED-edge lit sets almost always horrendous to view in the dark because of the flashlighting/clouding.  You can match or best the performance of a plasma in some areas with an LCD, but you'll have to pay A LOT more for one than a similar plasma.  There's a reason 9G Pioneer Elite plasmas from 2008 are still considered reference sets by many.  
cs85b03
Yep, plasmas are awesome if you like distorted red pixelization after less than a year of use.  But if you want a TV that doesn't degrade over time, LCDs are the way to go.
uronacid
"One of the trade-offs for this lower price is that the image generally is not as bright, so you need to be able to control the room lighting to get an equivalent picture." 

You contrast LCDs with plasma in the area of brightness, and I feel it gives the illusion that brighter is better. There is a reason pros give Panasonic and Pioneer (while they were around) kudos for making fantastic televisions. You fail to mention the broader color spectrum that plasma TVs have.  To preform well in dark scenery LCD televisions cheat by dimming the back-light so you can differentiate between colors on the screen. Problems occur when there are combinations of dark and light scenery with detail on both sides of the spectrum.

Plasma blows LCD away when it comes to this kind of imagery, and it's not as if I'm speaking about a niche either. Popular movies like the Dark Knight, Inception, or Terminator 2 have many dark scenes where detail is barely visible on an LCD. Video games are the real problem though. While playing high def video games, detail is important and dark scenery is common.
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