ORIGINAL INQUIRY:

2/15/13

Looking for a wise optics consultant who can help evenly light gnarly plastic lightpipes with a single LED.

Thanks,

Art

RESPONSES

Hi Art

I sometimes do some moonlighting and I've done a lot of optics work.  Sometimes I use SolidWorks + FRED and other times write custom component shape optimization codes in python.  Let me know if you're interested and you think the project would fit in 10-15 hrs week of availability.

Jamie Page

jamespage01@gmail.com

I used this guy in the past:

http://spie.org/profile/Stefan.Baumer-10853

but that was when he was working at Philips.  There might be someone else you could find through SPIE, though.  If you want to peruse his book, Handbook of Plastic Optics, I can drop it off at Lunar some evening on the way home.

I have also used Ray Hebert at Prisma Optics in Oregon - a lot cheaper and easier to work with, and he was very thorough.

http://www.prisma-optics.com/

I should mention that all this was about 5 years ago at another company.

Good luck,

Mark Glusker

glusker@yahoo.com

Art - The trick is to get as much light as you can collumnated and into the bundle at less than the internal angle of complete reflection. That is typically a few degrees.  The problem is that most stock LEDs have a much wider angle of dispersion than that, so a lot of light leaks out towards the sides in the first few inches. If you get to specify the design of the LED body, make the lens so that the die is right at the focal point of the lens. That way you'll get as many of the rays coming out as parallel as possible.  Am I making sense?

The angle of complete internal reflection is determined by the ratio of the densities of the two materials, typically acrylic plastic and air. I'm a tad rusty on that math, but you can look it up.

Roy Askeland did the light pipe for the AppleFax Modem and by limiting the minimum bend radius of the pipe got nearly all the light from the LED up, bent 90 degrees, and out the front. 

This is all pretty general advice since I don't know the details of your design.

-df

Dexter Francis <dwmfrancis@gmail.com>

Hi Art,

I hope all is well.

If you can't find an "expert" here's a design guide we've referred to in designing challenging light pipes we've worked on.

Regards,

Mike Strasser

Think2Build LLC

179 11th St., 3rd Floor

San Francisco, CA 94103

415.235.2233

think2build.com

Agilent Light Pipe Design Guide.pdf