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TMD's new LED display family
Toshiba Matsushita Display Technology Corporation display panels

LED technology is slowly being accepted by notebook manufacturers looking to improve the quality of their displays. With LED technology, manufacturers can produce thinner, lighter LCD panels which offer superior contrast and luminance. Other perks include high brightness levels, faster response times and lower power consumption than traditional CCFL LCD displays.

We've already seen notebooks hit the market that feature LED-backlit displays including the Sony VAIO TX3 Series, the Asus U1F and the Fujitsu LifeBook P7230. Toshiba Matsushita Display Technology Corporation (TMD) hopes to expand the LED-backlit field by offering a new family of displays ranging in size from 8.9" to 13.3" aimed at UMPCs, notebooks and Tablet PCs.

The displays have a thickness of just 2.5mm and advances have been made to reduce the weight of the panels. In the case of the 10.4" and 12.1" panels, weight comes in at a mere 4.2 ounces and 4.8 ounces respectively.

Power consumption ranges from 2.4 watts for the 10.4" XGA display to 4 watts for the 13.3" WXGA display. Brightness varies between 200 cd/m2 on the 8.9" display to 300 cd/m2 for the 12.1", 10.6" and 13.3" displays.

TMD is forecasting that over 50% of its LCD production will be shifted over to LED technology by the latter half of 2007.

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Why now?
By Kuroyama on 3/20/2007 9:46:39 AM , Rating: 2
What took so long? LEDs aren't exactly new technology, so unless there was recently a big drop in LED prices then what makes this economically feasible now but not say a few years ago?




RE: Why now?
By pro510 on 3/20/2007 10:09:07 AM , Rating: 2
I think LEDs do have a sort of Moores law, where for the same power they produce twice the light every 18 months or so. So it may be something to do with cost/power/brightness. It could also be to do with the spectrum of light emitted by the LEDs. You will need a white LED which has is made up of a broad even spectrum of light.


RE: Why now?
By AnnihilatorX on 3/20/2007 10:50:06 AM , Rating: 5
White LED isn't exactly new. While the familiar red, yellow, green LEDs have been around for centuries, blue LED hasn't. This is because making blue wavelength light is not poossible with Silicon based LEDs. Gallium Arsenide is used instead. Because the industry is so mature on Silicon, not much money had been invested in GaAs technology.

Since Red, Green and Blue light make white, the missing blue LED until now means we couldn't produce white LEDs earlier


RE: Why now?
By masher2 (blog) on 3/20/2007 12:29:23 PM , Rating: 4
Just to correct a few things, blue LEDs are made from gallium nitride, not gallium arsenide (which is used to make infrared LEDs instead). Also, white LEDs are not made from red, blue, and green ones combined. The most common process is a blue LED combined with a reactive yellow phosphorus. Another method uses an ultraviolet LEDs combined with RBG phosphors.


RE: Why now?
By ZmaxDP on 3/20/2007 1:33:31 PM , Rating: 2
There are quite a few color changing architectural grade LED lights out there that are a combination of individual Red, Green, and Blue LEDs that have individual dimmer controls for each. If all are on you get "white" light. You can approximate almost any color in the spectrum using these systems. They aren't technically "one" LED, but they are packaged into one "unit." So, you're both right...


RE: Why now?
By Oregonian2 on 3/20/2007 1:57:58 PM , Rating: 2
That "most common" method also is the cheapest (probably why it's the most common).


RE: Why now?
By Oregonian2 on 3/20/2007 2:02:43 PM , Rating: 2
I think the driving force for this development has been for large screen HDTV sets where the LED backlighting would cut power consumed a lot (one of the big problems). Having the LED's colors be appropriate, having it bright enough, having them be able to distribute their light evenly, and having all of that economically viable has taken a while.


RE: Why now?
By Omega215D on 3/20/2007 9:33:51 PM , Rating: 2
I was wondering the same thing. I have a LED flashlight from INOVA and it is damn bright white that goes up to 120 feet so imagine putting these in a display.


RE: Why now?
By Stele on 3/20/2007 9:52:56 PM , Rating: 5
Continuing from both AnnihilatorX and masher2's posts to answer Kuroyama's question, the point, therefore, is that we cannot (yet) make a 'pure' white LED the way we make red, green or blue LEDs... white LEDs, as masher2 noted, are made by using an LED combined with reactive phosphor to give off the white colour.

The problem is that this means there are two variables to watch over during the manufacturing process - the LED itself and the phosphor layer, compared to just the LED for the primary colour LEDs. LEDs, being semiconductor devices, are quite well understood and controllable in terms of manufacturing consistency and quality. The phosphor layer, however, is not.

As such, the manufacturing consistency - and hence the uniformity of the resultant 'white' colour - is notoriously difficult to maintain, resulting in many shades of 'white' in a particular lot. Worse, unlike CCFL tubes which generally span the entire height or width of an LCD, many LEDs are required per 'bar' for the backlight of large panels. Anything short of nearly-perfect colour uniformity across the board would result in off-colour patches on the LCD, and the LCD's colour uniformity subsequently suffers. This is the single largest obstacle, aside from the comparatively high unit costs of LEDs, to fully-LED backlit large displays. We are only now starting to see larger LED-backlit LCDs thanks to improvements in manufacturing processes for the phosphor, the deposition of the phosphor layer and the creation of optimum combinations of LED colours and phosphors. This improves both colour uniformity and yield, thus driving costs down.

Smaller displays, on the other hand, get off more easily because generally only one, or at most two, bright white LEDs are required: the LEDs are placed at a corner of the LCD and are coupled with lightguide tubes or plates to distribute their light throughout the panel. This small number of LEDs makes it a lot easier to ensure a uniform shade of white throughout the panel compared to large LCDs, which is why they are much more prevalent - at least for now.


Amen
By lumbergeek on 3/20/2007 11:11:34 AM , Rating: 2
One of my biggest headaches has been LCD monitors that have their backlight CCFL blow out. Nothing wrong with the panel, but the monitor is dead anyways. I see LED backlighting as being a solid-state life extender of LCD displays. I've had so many issues with the backlighting of monitors at work that it has kept me from being willing to invest my own dollars in an LCD TV at home. The fact that one can adjust the colour temperature and brightness of individual regions of the backlight will also go a long way to fixing the other problem of black level in LCD TVs. I for one will be glad to see CCFL backlights go the way of the dodo.




RE: Amen
By dgingeri on 3/20/2007 11:59:51 AM , Rating: 3
The problem with this is that while LED's are more durable and have a more predictable lifetime, they do actually have a shorter average lifetime than cold cathode tubes.

They generally last about 10% shorter than equal CC tube lights, but the bell curve of LED failures is more centralized. They have a less likely chance of failing early, but also a less likely chance to last longer.

Figure on LED backlit displays to last about 5-6 years, while the CCFL displays can possibly last as long as 10 years.


RE: Amen
By masher2 (blog) on 3/20/2007 12:42:59 PM , Rating: 2
Any references, as this is exactly the opposite of what I've heard. The figures I remember are CCFLs averaging an MTBF of around 50K hours, whereas LED backlights ran up to 100K hours.


RE: Amen
By Den on 3/21/2007 1:47:37 PM , Rating: 2
The problem is that MTBF is a measure of how likely something is to fail in it's service life, NOT how long it is expected to last. So if LEDs fail one fourth as often during their service life as CCFLs do, you could still have a CCFL with twice the service life and half the MTBF of an LED. There was a good article on MTBF and hard drives a few weeks ago, you can read that for more details on how MTBF say nothing about how long something will last, just how likely it is to fail during it's service life (which is almost never published).


RE: Amen
By ChronoReverse on 3/20/2007 1:47:30 PM , Rating: 2
I thought LEDs didn't usually burn out but rather grow dimmer with age. Would be rather similar to what happens with CRTs.


RE: Amen
By therealnickdanger on 3/20/07, Rating: 0
RE: Amen
By FrankM on 3/20/2007 6:19:10 PM , Rating: 2
And I'm more and more convinced that laser projection screens are the way to go, and not plasma. It's just a pity that there's rarely news of it.


RE: Amen
By therealnickdanger on 3/22/2007 9:14:10 AM , Rating: 2
Great, you go right ahead and buy a laser display. Oh wait...

If they can ever sort it out, SED would be ideal, but it's not coming for some time, so it's not really practical to pine over tech that isn't avilable yet.


RE: Amen
By ProxyOne on 3/21/2007 9:10:32 AM , Rating: 2
quote:
They generally last about 10% shorter than equal CC tube lights... LED backlit displays to last about 5-6 years, while the CCFL displays can possibly last as long as 10 years.

Umm...numbers don't add up? 10% isn't much but 40-50% sure is!


Terrific!
By lotharamious on 3/20/2007 9:34:37 AM , Rating: 2
quote:
TMD is forecasting that over 50% of its LCD production will be shifted over to LED technology by the latter half of 2007.

Wonderful. LEDs make LCDs absolutely terrific. The backlighting uniformity and color spectrum issues are tremendously improved. This truly is something that makes me happy to hear.




RE: Terrific!
By therealnickdanger on 3/20/2007 9:47:31 AM , Rating: 2
Maybe it's because the last review I read was over a year ago, but I thought that LED LCDs haven't turned out to be quite the quantum leap they are supposed to be. I know they offer improvements, but are they really that dramatically better? I have yet to see one in person, so I'm hesitant to get really excited.


RE: Terrific!
By TSS on 3/20/2007 10:12:24 AM , Rating: 2
well they are better and better is always....better.

point is that if the price stays (relatively) the same while quality improves, then it's never a bad thing.

though i am curious to see what technology we'll see for notebooks next, revolutionairy that is. i mean notebook displays have gotten thinner and thinner by a process of refinement, which this really is just another step in. bring on the laser displays :P


RE: Terrific!
By Quijonsith on 3/20/2007 10:13:41 AM , Rating: 2
LED backlighting enhances overall contrast. With LED backlighting, where there are specific areas of the picture that are dark the LEDs behind those areas can be turned down/off. With todays backlighting this isn't possible and the backlight can wash out dark areas if set too high, or make bright areas look too dim for the image if set low enough for shadows to look good. This is of course in addition to the other advantages LED backlighting has. I can't wait for this to become the norm, esp for desktop LCDs.


RE: Terrific!
By Aversio on 3/20/2007 10:46:50 AM , Rating: 2
quote:
Other perks include high brightness levels, faster response times and lower power consumption than traditional CCFL LCD displays....
Brightness varies between 200 cd/m2 on the 8.9" display to 300 cd/m2 for the 12.1", 10.6" and 13.3" displays.

Don't get me wrong I'm all for LED LCD's.. but aren't all current displays already that "bright"?


RE: Terrific!
By melgross on 3/20/2007 4:27:57 PM , Rating: 2
Not for laptops.


wtf
By goku on 3/21/2007 12:15:00 AM , Rating: 2
Huh? How the fuck would changing the backlight effect the response times???




RE: wtf
By Zoomer on 3/21/2007 10:11:52 AM , Rating: 2
If the whole screen goes from light to dark, they can turn off the backlight, which would have a response time of <1ms.

A little like cheating, I know.


"There is a single light of science, and to brighten it anywhere is to brighten it everywhere." -- Isaac Asimov











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