Looking for lens that will collimate 4 led dies 2mm apart

[JimboJones21]

I have an LED that has 4 1mm chips inside it, RGBA. When I use a standard luxeon LED lens the beam angle doubles because the led chips are all offset from the center by 2.5mm. It's a result of the light being reflected internally and exiting the lens not in a straight beam but more at an anlge. Without diffusion I can see the four separate sources on my projection surface.

I was wondering if anyone had any solutions for this probelm? I was looking at micro lenses because you could prossibly have a separate lens for each chip and keep them within the 2.5mm distance of each other.

The chips have to stay close for the color mixing, so to have 4 separate LEDs and 4 separate lenses creates too many color shadows because the LEDs are too far apart.

Thanks.

 

[IRstuff]

What divergence do you require?

TTFN

 

[JimboJones21]

The lens I have has a 15deg half angle, that works with a single led die. With the 4 led die place around the center the half angle has changed to 24deg (for the same 15deg lens). I want to be able to tighten the beam angle back down to 15deg.

 

[BioLED]

I have used a 4 die RGGB module (also 1mm die) from Lamina Ceramics (laminaceramics.com)with Fraen FHS series lenses that are designed for LED use. You can get a Lamina BL-4000 developers kit with the module and driver and two of the lenses in it (small angle and medium angle), or you can order the lenses separately from DigiKey (search on Lamina). The die spacing in this module is also >2mm, so it might work for your LED. The RGB light convergence works well.

Who makes your RGBA LED? I'd like to give it a try.
- Thanks

 

[JimboJones21]

Hey, lamina makes it, I've tried the fraen lens and you can see the 4 separate dies on the projection surface. I've thrown a micro lens array over the lens to diffuse the light. It works, but my beam spread is still too wide. I think somehow a lens that will colimate the light from each die has to be made. Since the dies are only mm's apart I'm not sure how that lens would look. I'll check out the BL4000 lens, that's the massive square led correct?

 

[JimboJones21]

My bad, the Bl4000 is similar to my LED!! But the dies I have are arranged in a square, these seem to be arranged in some unsymetrical way, there are also more dies, but I will try the lens, 10deg. That's pretty tight, the front looks like a micro lens array. I wonder what the losses are like. Thanks BioLED.