[Cialug] OT: LCD Pixel power?

[Nathan Stien]

On 5/24/07, Nathan C. Smith <nathan.smith at ipmvs.com> wrote:
>
> I have a question regarding LCD displays.  Does it take more power to show
> pixels of a particular color - are dark pixels harder on power than light
> ones?  Or does the nature of the LCD require even power through screen at
> once?  Is the backlight itself a bigger power hog than the screen?  (If it
> is bring on the LED backlights!)

I'm not an LCD expert, but I can tell you that the backlight is
definitely the power hog.  My cell phone, for example, keeps a time
display on the external LCD at all times, and it has great idle
battery life.  And just think of how long a non-backlit LCD wristwatch
can live off a tiny watch battery.  Years sometimes.

> The background of this question is if there is if there are any screen
> contents or color schemes that can reduce battery usage - I'm betting there
> aren't.

I am inclined to agree.  It's the photons that are expensive; all the
LCD itself has to do is selectively filter the light source.  A dark
but backlit screen is basically just heating itself up, since the dark
pixels are absorbing the light.  You're burning the same wattage on
the backlight no matter what you do.  (Well, unless you just turn down
the backlight...)

-- 
Nathan P. Stien
Consulting Engineer / Software Developer
Embedded Systems Electronics and Software
http://linkedin.com/in/nathanstien
Mobile: 309.241.2581