LCDs switching to cheaper, lower quality white LED backlights
By Richard Lawler 
posted Oct 10th 2008 1:42PM
posted Oct 10th 2008 1:42PM
In the year 2009....LED-backlit LCDs will probably be increasingly common, and why not? Everyone wants a flat panel with questionably-measured contrast ratios full of so many zeroes they run off the spec sheet. but in order to bring the tech to the masses, Digitimes reports manufacturers may switch from current red/green/blue LEDs to white LEDs.They claim white LEDs meet the mark in terms of power savings, but won't measure up when it comes to accurate color reproduction. Specifically mentioned? Sharp, LG, AUO and "others" (Samsung has already jumped on the bandwagon) so when you meet a guy selling cheap LED HDTVs from the of a van, add one more thing to check while making sure you aren't purchasing an oven door.
Are these still better than florescent light as far as color reproduction, size of color gamut and longevity? Also, don't LED's lack the flicker associated with florescent lighting?
Current LED LCD's are just too expensive.
Fluorescents with electronic ballasts flicker at about 40,000 Hz or higher You can't see the flicker, it just isn't an issue. This includes not only backlights, but also compact fluorescents and every T8 fixture (and even older fixtures when paired with electronic ballasts).
LEDs are generally driven by switching power supplies, so in theory they flicker too. The switching rate is going to be probably 200,000 Hz or higher (perhaps even 100x higher), so you'll never see it either.
The white LEDs in question use single-color LEDs exiciting phosphor coatings. Since they use phosphors like a fluorescent light, they have similar color rendition to fluorescent light in may ways.
Not that 3 color LEDs gives great color rendition either, since LEDs produce line spectra too (perhaps not as tight as phosphors though).
If you are wondering why the Sony XBR 8 cost so much keep in mind they are NOT using White LEDs they are using the Tri-Color LEDs.
As long as someone continues to make tri-color LED TVs, and they don't abandon it completely, assuming that even white LEDs are better than CCFLs, then it shouldn't be a bad thing, right?
It disappoints me to hear that there is yet another consideration that has to be made when comparing televisions. I wonder if this will even be something that you can read on a spec sheet, or if the manufacturers will hide it all together. Adam http://www.hdupdate.com
Well, for what is out there now:
Samsung A950/81 - white
LG LG90 - white
Sony XBR8 - tri-color
Sharp XS1U-S - tri-color (just announced)
Not sure what else is coming.
What I've been wondering is how long is the LED sets going to be around.
Everyone is on this bandwagon of OLED's as the future.
Sony and Samsung say they should have large OLEDs around 2010.
That would give LEDs only a REAL 3rd generation on the market by the time larger OLEDs are released.
Granted it might turn out that the LEDs will be the lower end at that time with the OLEDs with the premium prices.
I will say the times I've seen the LED models in person they lose quite a bit of color detail at side angles. It looks perfect sitting right in front of the set but the colors wash out at wide angles.
John-MichaelDelValle.com