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-   -   Absurd LED thrower optics? (https://laserpointerforums.com/f49/absurd-led-thrower-optics-53990.html)

Toke 08-06-2010 08:25 PM

Absurd LED thrower optics?
 
I am not quite sure where to put this.

Does anyone know of optics that will let a small flash light give a laser like beam at night?
It would have limited practical purpose, but I think it would look cool to have a LED 1xAAA or such that can make a dot at several hundred meters.

RA_pierce 08-06-2010 08:32 PM

Re: Absurd LED thrower optics?
 
It is possible to get good throw with an LED with the right optics and reflector but a dot at several hundred meters is unlikely to happen. Otherwise we would all have a cheap LED pointer in all colors.

The reason laser light can do the amazing things it does is because all the photons are in phase. Put simply, they all travel parallel to each other. Coherent light is a unique property of lasers.

Other light sources like incandescent bulbs and LEDs emit incoherent light, meaning that the photons emitted are scattered. This makes it impossible to get a laser-like beam from a flashlight.

Toke 08-06-2010 08:36 PM

Re: Absurd LED thrower optics?
 
Ok, I guess I put it wrong. :(
I realise the difference between laser and other light.

What I am looking for is a flash light with a really narrow beam that will go far.

Gryphon 08-06-2010 08:39 PM

Re: Absurd LED thrower optics?
 
^ Your looking for a flashlight with very good throw, as opposed to spread...

Toke 08-06-2010 09:20 PM

Re: Absurd LED thrower optics?
 
Quote:

Originally Posted by Gryphon (Post 759787)
^ Your looking for a flashlight with very good throw, as opposed to spread...

Yes, and a quite small one.

jmgallego 08-06-2010 09:46 PM

Re: Absurd LED thrower optics?
 
Quote:

Originally Posted by Toke (Post 759802)
Yes, and a quite small one.

Deluxe Extreme has some good throwers at a good price. Read the reviews and posts for those that you may be interested. Candlepower has also good reviews by pros.

Toke 08-06-2010 10:14 PM

Re: Absurd LED thrower optics?
 
Quote:

Originally Posted by jmgallego (Post 759816)
Deluxe Extreme has some good throwers at a good price. Read the reviews and posts for those that you may be interested. Candlepower has also good reviews by pros.

Thanks, candlepower look like a great site.

BShanahan14rulz 08-07-2010 02:13 AM

Re: Absurd LED thrower optics?
 
You know how with lasers, the fatter you expand the beam the better it can be collimated? Well an LED is a larger source compared to the tiny emitting area of a laser, so to get the best throw you would end up with a pretty big beam.

This is usually achieved with an aspheric lens, just like what we use with lasers, but much bigger, the bigger the better, generally speaking.

You can imagine, buying a lens from a scientific supply company can get pretty expensive. Coming from the automotive HID retrofit crowd (not the annoying drop-in kits), I can also remind you that there are other sources for large clear aspherics. Search for ZKW-r lens (3" diameter) or TSX-r and FX-R lens' (2.5" diameter) to get some ideas. They are used to provide a sharper, more colorful cutoff on automotive headlamp projectors that are commonly used in the retrofit community. Usually sold in pairs, though.

You can also get decent results with narrow-angle TIR optics (total internal reflection). These look like moulded cones of clear plastic. I don't know if you will find one that is compact and still gives the parallel beam that you are looking for, though.

If you are looking around CPF, search for DEFT ;-)

Toke 08-07-2010 04:05 AM

Re: Absurd LED thrower optics?
 
If you are looking around CPF, search for DEFT ;-)

DEFT looks like a cool custom :D
The beam looks great, but not pocket sized. As expected am not the first to wonder about this, and the answer there seems, as you point out, to be that size matters. :)

3zuli 08-07-2010 07:13 AM

Re: Absurd LED thrower optics?
 
ur loking for this: DealExtreme: $9.52 C30 Flood-to-Throw Zooming Glass Optics Cree P4-WC 100-Lumen LED Flashlight with Strap (3*AAA)
I own it, it's an epic thrower :D but it doesn't make "dot", but an square with shape of the emitter (see this video @ 0:51)


btw if u want longer run time buy the 18650 battery version http://www.dealextreme.com/details.dx/sku.14450

Toke 08-07-2010 10:04 AM

Re: Absurd LED thrower optics?
 
Thanks. :)

millirad 08-07-2010 10:41 AM

Re: Absurd LED thrower optics?
 
Combine that focusing element with the evil high powered red led in the Casio projector. ;-)

3zuli 08-07-2010 11:34 AM

Re: Absurd LED thrower optics?
 
Quote:

Originally Posted by millirad (Post 760337)
Combine that focusing element with the evil high powered red led in the Casio projector. ;-)

that would melt that plastic lens LOL

and if not, then
:lasergun:

millirad 08-07-2010 11:55 AM

Re: Absurd LED thrower optics?
 
I looked at the advertisement and it says glass optic. But the plastic housing would have to be replaced with aluminium. ;-) It could be our first flashlight burner!

BShanahan14rulz 08-09-2010 06:24 PM

Re: Absurd LED thrower optics?
 
the x2000 was my first flashlight. The optic made amazingly smooth output, and a nice sharp image of the die at distance. Mine the body was metal and the lens was plastic. Came with a 3xAAA carrier and a spacer sleeve for 18650.

Tech_Junkie 08-09-2010 08:53 PM

Re: Absurd LED thrower optics?
 
Quote:

Originally Posted by millirad (Post 760364)
It could be our first flashlight burner!

There are a few. I cant find the video where is shows a glass lens from DX added to a flash light, and starts cardboard on fire.







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