Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

Thanks for supporting LPF!

Avery's Instagram | Open Source Cybersecurity Software by Avery | Considering selling LPF, DM if interested

Absurd LED thrower optics?

Toke

New member
Joined
Jul 25, 2010
Messages
1,109
Points
0
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

Well-known member
Joined
Sep 16, 2007
Messages
3,583
Points
113
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

New member
Joined
Jul 25, 2010
Messages
1,109
Points
0
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

New member
Joined
May 4, 2009
Messages
1,837
Points
0
^ Your looking for a flashlight with very good throw, as opposed to spread...
 

jmgallego

Active member
Joined
Apr 9, 2008
Messages
374
Points
28
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

New member
Joined
Jul 25, 2010
Messages
1,109
Points
0
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

Well-known member
Joined
Dec 29, 2009
Messages
3,151
Points
63
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

New member
Joined
Jul 25, 2010
Messages
1,109
Points
0
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. :)
 

millirad

Well-known member
Joined
Apr 28, 2009
Messages
2,425
Points
63
Combine that focusing element with the evil high powered red led in the Casio projector. ;-)
 

millirad

Well-known member
Joined
Apr 28, 2009
Messages
2,425
Points
63
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!
 
Last edited:

BShanahan14rulz

Well-known member
Joined
Dec 29, 2009
Messages
3,151
Points
63
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.
 




Top