Power saving method in LED TV?

[eem2am]

Hello,

I have heard that the latest method of saving power in LED-Back-lit, LCD Televisions is to dim the LEDs behind certain parts of the screen image that are dark.

Do you know if this is true?

-The thing is, Television pictures are moving constantly, and from frame to frame, different parts of the screen are constantly varying in light level depending on the particular movie scenes playing.

So how on earth are they going to manage to dynamically and differentially dim the particular LEDs over each square inch of the screen throughout the course of a typical movie?

This would require hundreds of switch-mode Dimmable LED Drivers.
-It is completely impratical.(?)
-There would be losses associated with each of the hundreds of Dimming LED Drivers that would make the efficiency relatively poor.

So is this idea of dynamically and differentially dimming various LED banks in a TV Backlight just a rumour?

 

[Resqueline]

I haven't seen the actual wiring diagrams for this but comparing it to the task of driving all the individual pixels of a power-hungry plasma screen I'd say it's trivial.
The computing task is certainly trivial compared to the calculation of intermediate picture frames to make up for the originals "missing" (for high frame rate TV's).
I'd be very surprised if it's just a rumour, or a marketing gimmick.

 

[(*steve*)]

eem2am, the only backlights I have seen are actually ones that run along one edge of the screen. Admittedly these are for smaller screens than TVs, but the general concept behind these things are that the light is diffused over a very wide area.

If you can get some hard information that screens use this, then that would be interesting to see.