Linked by Howard Fosdick on Tue 2nd Aug 2011 22:18 UTC
Editorial Your computer is an important energy consumer in your home. Can you save energy when using it? This article offers a few tips.
Thread beginning with comment 483253
To read all comments associated with this story, please click here.
White instead of black
by Dr-ROX on Wed 3rd Aug 2011 08:00 UTC
Dr-ROX
Member since:
2006-01-03

For LCD screens, you can make a screensaver, that shows white color instead of black. LCD works in that way, that power is needed to make black color. White is the natural state of the screen, so it only uses power for backlight. And if you turn of the screen light, then it saves power completely. Try white color with a voltmeter.
With plasma and CRT screens black is the natural state of them, so showing black should save power. But those screens are eating more of it naturally.

Reply Score: 1

RE: White instead of black
by Neolander on Wed 3rd Aug 2011 08:58 in reply to "White instead of black "
Neolander Member since:
2010-03-08

What about LED-backlit LCD ? Aren't they smart enough to selectively turn off some of the white LEDs when displaying black ?

Ah, can't wait until we have OLED and transflective screens everywhere ;)

Reply Parent Score: 1

RE[2]: White instead of black
by David on Wed 3rd Aug 2011 17:02 in reply to "RE: White instead of black "
David Member since:
1997-10-01

I believe that most LED backlights don't actually have a lot of LEDs behind the screen (known as "full array") that can be turned on and off, but rather have LED emitters at the edges of the screen that uniformly illuminate the area behind the LCD panel.

There is a technology known as "local dimming" that works like you describe, but it's only in high end TVs at this point. I don't know if anyone is making computer monitors with local dimming.

Reply Parent Score: 1

RE: White instead of black
by transputer_guy on Wed 3rd Aug 2011 18:39 in reply to "White instead of black "
transputer_guy Member since:
2005-07-08

I think you are quite wrong there.

It is a fact that the LCD screen pixel structure is only about 5% efficient at letting the light through when fully on, that means 95% of whatever the light source is either CC tube or LED is blocked and is therefore turned to black body heat. If the screen is black it would just be 99.9% instead. To save power means controlling the light source power.

There was/is a company called Unipixel that had a LCD alternative that claimed 60% efficient light cell based on a neat MEMs opto capacitive structure. They even licensed it to Samsung in 2009, not a squeek since though. When driven by side lit LEDs, its power use would be far below todays LED LCD panels which are mostly already good enough.

Reply Parent Score: 2