Aspheric + Reflector?

[Codiak]

I'm wondering about the benefits of using both an aspheric and a reflector in the same application. For my purposes the lens is a given; however, since the domed-led creates a 180degree light source would a short smooth reflector offer any value?

• short = no taller than the dome (SST-50 in this case)

If a reflector would be useful:

• What diameter or angle would be ideal?
• Would the Focal Length of the Aspheric matter?
• Where could one be purchased?

Thanks

 

[The Dane]

Aspheric + Reflector = Weird beam!!!
If it worked it would have been done by now:shrug:

 

[KuKu427]

It would look like this.

 

[Codiak]

It would look like this.

Thanks!

 

[Codiak]

Aspheric + Reflector = Weird beam!!!
If it worked it would have been done by now:shrug:

Stopped by Walmart today... found a new 3watts LED light they call "Daylight"

They have implemented an asherphic + reflector and made it focusable.
Nice simple design and having fun taking it apart.

 

[Benson]

Aspheric + Reflector = Weird beam!!!
If it worked it would have been done by now:shrug:

It has been done by now. My First Alert 10-color has an RGB emitter with a diffusing element over the 3 dies, so you've got ~8mm (almost) uniform glowing disk. They put that in a reflector behind a lens, so that the flood from the reflector comes right to the edge of the rather wide beam from the emitter. If you look into the light, you can just see a dark line between the emitter and it's reflection in the reflector, but because the aspheric is defocused, that doesn't show up in the beam. It's great for a nice smooth flood...

 

[HumanLumen]

I have used small section of a mcr-16 reflector (about 10mm in height) to capture the spill from an XRE when used with an aspheric. The aspheric captured +/-45 degrees (30mm diameter and 15mm focal length) and the reflector captured the remaining light outside of this area. Note that the focal height of the reflector needs to be further away from the LED as the aspheric will refract the captured spill from the reflector. In my application, this enabled a reasonable spill in addition to the intense hotspot from the lens. If the focal point in too low, you end up with a void around the hotspot.
Aspherics do not work well with an LED with a wide dispersion angle - you cannot capture enough of the light to make it any better than a reflector.
HTH

HL

 

[Codiak]

I have used small section of a mcr-16 reflector (about 10mm in height) to capture the spill from an XRE when used with an aspheric. The aspheric captured +/-45 degrees (30mm diameter and 15mm focal length) and the reflector captured the remaining light outside of this area. Note that the focal height of the reflector needs to be further away from the LED as the aspheric will refract the captured spill from the reflector. In my application, this enabled a reasonable spill in addition to the intense hotspot from the lens. If the focal point in too low, you end up with a void around the hotspot.
Aspherics do not work well with an LED with a wide dispersion angle - you cannot capture enough of the light to make it any better than a reflector.
HTH

HL

great info... Spill is the bane of my light, short of using a pinhole to filter prehaps theres value here... will play for a while

 

[HarryN]

Hi, I have done it with several LEDs. The most challenging with with a Lux V 4 die LED with only 12mm dia to work with.

I will be honest - it was an expensive learning experience, but I learned a lot. The LED, reflector, and lens need to match to each other to be happy with the results. The tolerances required are much tighter than you expect they will be in multiple aspects of alignment, or it just does not work well.

It is a LOT cheaper and faster to buy an off the shelf optic, with 90% of the same result.

If you really want to pursue this, I pm me and I can save you a lot of time and money on it.

 

[gcbryan]

Stopped by Walmart today... found a new 3watts LED light they call "Daylight"

They have implemented an asherphic + reflector and made it focusable.
Nice simple design and having fun taking it apart.

I'd like to hear more about what you figure out from playing around with this light.

Is the aspheric anything that would fit any of the dive lights that we talk about in the diving forum (W200 for instance) and how is this light focused?

Is it a sliding motion in a tube or is it a threaded head with a fixed emitter?

 

[bshanahan14rulz]

Isn't that the duracell light?

 

[Codiak]

yeah, just forgot to post the brand name