Novel L.E.D. source for interior lights

[TIMEMACHINE]

Originally Posted by bhayden

What about lens covers. I realize this isn't the optimal solution but if the choice of LEDs is fixed can the light be "toned down" with a plastic diffuser?

-Bernie

Bernie...you are headed in the right direction...very good question.

LEDs are perfect light sources for shaping beam patterns using a fairly new form of optics known as Non-Imaging Optics or NIO. The primary function of the NIO is to collimate the light which is emitted by the LED. An LED with a lambertian emission pattern is best for this type of optic. I know this is pretty techy, but for those who are really interested I will continue. Once the light is collimated (the beam pattern is restricted to less than 5 degree spread), then a diffuser can be placed in front of the light to produce the desired final light pattern. A holographic diffuser is best for this job due to its high transmission value, in other words 90% to 95% of the light passes through the beam shaping diffuser. Conventional diffusers are far less efficient, many allowing less than 40% of the light to pass.

Up until recently, most LED products for the consumer market have had either no or poor performing optics. This is changing as the market matures and it is probable that manufacturers will start providing optics to match the application as opposed to just throwing out light in all directions.

3M has been the pioneer in high transmission plastic diffusers (similar to the material used on a laptop or PDA) and other start ups are producing similar product giving the manufacturers new opportunity to give us new designs.

In regards to a practical example of the optical techniques, take a look at the newer generation of LED lamps in the automotive market, great effort has been made in smoothing out the illumination of an LED brake lamp to eliminate the spotty look of LEDs. My guess is that this is the type of optic that the majority of our members would prefer when implementing LEDs into their interior lighting scheme.

Maybe techy, but I hope it throws a little more light on the subject.

John

[HowieE]

Originally Posted by TIMEMACHINE

Maybe techy, but I hope it throws a little more light on the subject.

Keep the "techy" coming because the LED sellers are short on Tech in thier advrtising and it's information we need.

[Fishnstream]

WOW LED'S I have jut purchased two 7 inch tail lights for my 64
Tradewind. Looks like they should mount very nice without changing the look of the rear of the unit. They are BRIGHT. Purchased from Princess Auto Will post pics later Thanks