multiple-color backlight

[dpopiz]

this may not exactly be highly technical, but I think it's the most appriate forum here...
AT MODS: how about an electronics forum?

It won't be happening.

AnandTech Moderator

I've suddenly been seeing a lot of electronics with LCDs where you can choose from 7 colors or something for the backlight. It must be pretty cheap to implement. Is this a new development? How do they do it?

 

[arcas]

I don't know if the devices you're referring to use LEDs for backlighting but variable-color LEDs exist and could conceivably be used for such purposes. Nichia makes one (model NSTM515S) that features true RGB operation: has red-, blue- and green-emitting chips inside, each with its own cathode pin so the LED has 4 pins total. By hooking each cathode to a variable resistor, you can vary the color...just like varying the R, G, and B settings in a typical color palette.

 

[dpopiz]

I don't think they use leds for backlighting, because don't led backlights always have uneven lighting? the ones I've seen just look like EL. you can probably find something like this at any electronics store -- lots of recent stereo components, etc have them

 

[Mark R]

LEDs are the most common illumination for backlighting in devices like mobile telephones, and other items with small screens (certainly all Nokia telephones use LEDs, with the exception of the 7650).

For devices with larger screens, then EL is used because it is slightly more even.

Multi-colour LEDs are readily available, and these can be used for this. Although, you don't actually need to have the different LEDs in one package - they can be seperate, if there is enough diffusion in the system.