I need to know whether I can just use a lense or if I need a collimator

I am building a DIY headlight. It is a cree LED for CHA0410. I bought it off digi key. Here is the link.

https://www.digikey.com/en/products/detail/creeled-inc/CHA0410-0000-000N0H0A30G/17627920

I am not a physicist, please don’t make things complicated. I am just an ebike builder needing a headlamp… Also please don’t tell me to go and buy a head lamp, because I already built this one.

Ok here’s what I need to know

DO I need a collimator for this LED?

OR can I get away with just using a lense?’

What would happen if I just pop a bracket over the LED with a lense and no collimator? An unsuable working light?

?Here is a link to the lense. They sell a collimator bvut IT"S TOO BIG for this LEd

IF you have a 12 volt LED that will fit that collimator and is high quality, an cheap, ill bite. But you won’t find it. I already did my research.s\

or converserly if you know a collimator FOR THIS LED but i already asked digi key they don’t have it…

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A collimator is a lens. A lens refracts light.

An optical window is not a lens. It does not refract light. Sure, most people call optical windows lenses, but I am not one of those.

Because of the above mentioned, it is not super clear what you mean when you say:

You also did not state what you are trying to achieve. Nobody can answer your question without knowing your objective.

Headlight for your head, or headlight for a vehicle?

If you’re building something for a vehicle, just buy an off the shelf product instead.

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FOr the head hoop, it’s a working light and might be used for a bicycle if the main head light fails…

Ok.

I meant the reflecty thing inside flashlights when I Say collimate. Would just the 60 degree lens be fine or do I need the reflecty silver thing you find inside most flashlights?

I know the light throw will be crazy with out the silver reflecty thing. But I can live with that I suppose. Just spewing lumens everywhere.

I

The collimator should be used by itself, not in combination with a reflector. The collimator should produce a “beam” of sorts, it will not spew lumens everywhere. The distance of the collimator from the LED will affect the beam angle produced.

It would be safer to purchase a decent bike light, unless you are good at design and fabrication and can produce something reliable.

Ok, so all I need is the collimator? The light is built, and works, and is reliable, so there is not way I am going to buy a bike light.

The only issues I am facing is protecting the cob LED from damage. My original was damaged. I can handle everything except the lens design

CAN you explain what each peice does…

1)Lens
2) Glass relfector
3) Collimator.

Would it be ok to use just the lens from this kit? How would the light get thrown? Im not picky about exactly how the light gets thrown as long as it is directed SOMEWHAT. Doesn’t have to be amazing, just good enouggh

Depends on “good enough”.

Some setups use the optical system (reflector/TIR/etc) to press down on the LED to get good heat transfer to the heatsink.

If you’ve already got good heat transfer, yes sticking the flat glass window over the top will protect the LED, though the light will be more of a floodlight than spotlight.

Just go for it and tell us how it works. If it’s no good, upload some pics and you’ll get some more specific advice.

Oh I see. I didn’t look at the kit closely before. I’ve never seen a kit like that but it looks like the reflector is more of a holder / positioner for the collimator, and it blocks the spill light from escaping. It might affect the beam quality negatively because an “image” of the reflector may be projected.

There are three pieces to the kit but there is only one lens. There is a lens, a metal bracket, and a reflector/holder piece. The collimator can be used without the reflector, yes, and the projected image may actually be better without the reflector.

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I think you mean a “reflector”. The shiny usually sort of conical part that has the light source at the bottom (focal point). Typically this part is just called a reflector, not collimator. If anything, the Total Internal Reflectance (TIR) part is closer to meeting the definition of collimator

Most designs use either a reflector or a TIR optic (many call it a lens) , or, like your kit, an aspheric lens, but not both reflector and optic.

Yeah, without seeing the beam, I think that reflector will just sort of muddy up the beam pattern. But it is the part that locates the lens…

Pretty sure the bracket would hold the lens flush to a flat surface. No need for the reflector.

Where do you buy your kits? This is the only kit on Ebay, and Ali baba. IF I could get one with a slimmer reflector it would do a better job reflecting. I checked digi key and they don’t have the reflector that mates perfectly with this LED. I think it was designed for a high end flashlight. I don’t think I could replicate that lens design

I plan on using thermal glue and I have a good heat sink for it. Will thermal GLUE be enough? I was using thermal paste and the lens I was using was pushing down on the LED which ultimatey destroyed the COB. The array was damaged and now won’t turn on.

Flood light is fine. I tested this LED “naked” to ensure it wasn’t DOA. IT seemed to a pretty good job as a flood flight.

BUt I do hope the Lens can get my beam just a LITTLE pointed. Just a little bit would be awesome. I am looking hard at the 60 degree kit, unless you guys have a better kit in mind.

I just buy optics and pair them with a given LED. KaiDomain has a large selection of reflectors as well as AR coated windows. Ledil, Carclo, Khatod, et. al. are optics manufacturers with extensive catalogs. Most of their optics can be purchased from Mouser, Digi-Key, etc. Convoy store offers most of their TIR optics and windows and reflectors as stand alone items.

CHA04010 has a 4.2mm diameter LES which is not too large. It should work ok in many common reflectors and optics. “Orange peel” reflectors or diffused TIR optics would help to smooth out the resulting beam from the COB LED. Reflectors and TIR optics tend to be more efficient than spherical or aspheric lenses.

What about a bracket that perfectly mates with the lens? I really need that bracket to hold everything in place with screws.

Also the glass reflector cannot push down on the board because it will ruin the circuity. I think I will have to fore go the reflector

Yea, mount things as required. You’ll get it figured out.

Best of luck.

I think youre missing the 4th piece. The bracket that goes over the cob. Kinda like this image shows

Cree says you can use any existing high intensity cob holder that fits. If you have a bracket that works go with that.

Then screw it down to a good sized heatsink

Thanks jeff,

I think the plan then is to only buy the bracket off of ebay. I will size up everything else to that bracket. Wish me luck. Its gonna be a lot of searching.

If it helps, Cree suggests using brackets and optics made for Citizen high intensity cobs for their CHA series. I’m guessing because they have similar dimensions and the citizens have been around for awhile so there’s more support for them at the moment than the new CHAs

Looks like I can get away with just using a reflector that perfectly mates with this LED. any ideas on a good lens? OR will pretty much any do?