# aspheric lens idea



## Bushman5 (Sep 13, 2007)

i keep reading how aspheric lens transmit the image of the LED itself. What would happen if you VERY lightly frosted the outer portion of the aspheric lens? ie: just barely enough to remove the sheen from the lens...

thoughts? ideas?


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## Led_Blind (Sep 14, 2007)

Remember that optics work by refraction. ANY material placed on them will change their properties. 

Just like painting the bottom side of an optic with shiny paint effectively destroys the optic.


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## Bushman5 (Sep 14, 2007)

mmm.. good point... i never considered that... 

thanks.


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## LuxLuthor (Sep 15, 2007)

You are better off (at least with the asphericals I have) to just put it slightly out of focus to get rid of the LED details displaying. It's still as effective for throw and small spot.


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## Nitro (Sep 15, 2007)

What might work is if you frosted the LED itself. You then would be projecting a ball of light, instead of the emitter.


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## HarryN (Sep 15, 2007)

Nitro said:


> What might work is if you frosted the LED itself. You then would be projecting a ball of light, instead of the emitter.



Sort of like the Cree package, with the phos on the inside of the outer plastic lens. Putting it slightly out of focus works well for me also.


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## sysadmn (Sep 17, 2007)

The effect isn't pronounced in the real world. At 20 feet I can get a nice image of either the led or an incan filament on a smooth wall. When I shine the same light at my neighbor's garage door (across the street from me), you just see a bright rectangle with a bit of pattern. When you shine it on an irregular surface such as trees, you can't even see the pattern.


Beamshots:
https://www.candlepowerforums.com/posts/2083323&postcount=3
https://www.candlepowerforums.com/threads/171503

Neither of these are my photos - just threads that Search found.


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## faiz23 (Sep 24, 2007)

in my acura i am having hid retrofitted from infiniti fx35 bixenon and acura tsx. both those models also came with fresnel lenses in 2006. they have a wavy frosted lens that helps smoothen out the cutoff instead of being super sharp.i have the ultra clear version that throws a very nice cutoff on both projectors. could you not use a fresnel lens. the projector on the left is a tsx with clear lens and it will be used in the projector on the right with the fresnel lens fx35. i found these pictures on a another forum they are not mine.


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## sysadmn (Sep 26, 2007)

Yes, a fresnel can work. Several flashlights use them. Here is an example.
Google "fresnel flashlight patent" for other applications.


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## faiz23 (Sep 30, 2007)

i think a fresnel would work great in a light since it has rings to soften the beam a little and reduce sharpness. In HID's for car most people hate fresnel since they like a nice sharp cutoff and want the color from a clear lens. Check out www.hidplanet.com/forums you will find fresnel lenses for cheap since everyone hates them on there. not sure if the focal length and all that good stuff matches but in the university section of the forum they have a thread that gives specs of all projectors and lenses. 

thank you


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