I think I have this in the right forum since it does pertain to dash lighting . Can anyone tell me how to control the wavelength of an LED bulb . I was poking around on a Volkswagon site and discovered exactly what VW does to achieve the intense violetish blue of their dash lighting for the guages and LCD displays . They use 3.5 volt blue leds , and the wavelength needs to be 430nm , then that is run thru a translucent white filter ( i.e. the layer of white on the back of the guage face that make the icons look white when unlit ) . I know how to do everything but control the wavelenth , if that is even something you can control . All the Blue LED's I see advertised are 470nm , which the same site said will produce a darker blue than the VW lighting . VW actually has this color patented , another worthless bit info I noticed .

Thanks for any help

Derek

 

The wavelength is basically another word for the color and is an inherent property of the LED itself. You'd have to find LEDs made to produce that specific color, and if that's true (that the "color is patented"), then you may not be able to get a hold of them save from a wrecked VW.

To some extent you could modify the perceived wavelength by using filters, but getting the exact hue wouldn't be easy.