Constraining the path of an infrared LED

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Discussion Overview

The discussion revolves around methods to constrain the beam width of infrared LEDs, particularly over a distance of about 2 feet. Participants explore various approaches, including the use of lenses, reflectors, and optical fibers, as well as considerations for alternative light sources like laser emitters.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about specific infrared LEDs with narrow beam widths and suggests the possibility of using a lens to control the beam.
  • Another participant proposes using a reflector element to focus the beam and questions the availability of IR lenses.
  • It is noted that for typical 905nm infrared LEDs, simple lenses may perform similarly to those for deep red LEDs, and a B+W security camera could assist in setup and focusing.
  • A suggestion is made to use a short length of tubing to maintain a narrow beam over a couple of feet, with the method depending on specific requirements.
  • One participant shares a link to an infrared LED with a 7-degree beam width and mentions a past modification involving changing the diode.
  • There are discussions about the visibility of infrared light through cameras, with some participants experimenting with cell phone cameras and webcams to observe the emitted light.
  • Another participant recalls using optical fibers in labs to contain the beam from IR emitters and suggests this as a potential solution.
  • One participant expresses a need for low-cost suppliers of laser pointers, noting confusion in their search results.
  • A question is raised about the relevance of laser pointers, which typically emit visible light, in the context of the original inquiry about infrared LEDs.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best method to constrain the beam width of infrared LEDs, with multiple competing views and suggestions remaining throughout the discussion.

Contextual Notes

Some participants express uncertainty about the definitions of "constrained" and the specific requirements for beam width control. There are also unresolved questions regarding the effectiveness of different methods and the characteristics of various light sources.

dingpud
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Are there any specific infrared LED's that have a narrow "beam width" when emitting? If not, does anyone know of a way to constrain it? A lens perhaps?

I would like to control the beam width over a distance of about 2 ft. I might need to go with a laser emitter...

Any suggestions would help.

Thanks,
 
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Maybe use a reflector element to focus the beam? Not sure about IR lenses. Did you google that?
 
For a typical 905nm (TV remote type) infrared led, most simple lenses will work pretty much the same as for a deep red led.
A B+W security camera is very useful for setup and focussing.
 
Using a short length of tubing will keep the beam fairly narrow over a couple feet.
The method you need to use depends on your exact requirements.
 
This all helps.

Thanks for the links.

If I get any results, I'll try and post them on this thread.

Thanks again.
 
mgb_phys said:
For a typical 905nm (TV remote type) infrared led, most simple lenses will work pretty much the same as for a deep red led.
A B+W security camera is very useful for setup and focussing.

I wouldn't know if my TV remote is IR or UV. Out of curiosity I tried my cell phone camera. It picks up the LED output, and displays it as pale blue.
 
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Out of curiosity I tried my remote on a web cam.
It's definitely an IR remote, but it does indeed show blue.

Looks like the camera color processing folds redder than red back over into blue.
I wonder if a UV source would show up as red for the same reason.
I don't have a UV source to try this.
 
The fiberoptics we used in labs at school had IR emitters that were encased in reflective material, so all the energy went into the fiber. BTW, have you thought of using an optical fiber to contain the beam?
 
  • #10
NoTime said:
Out of curiosity I tried my remote on a web cam.
It's definitely an IR remote, but it does indeed show blue.

Looks like the camera color processing folds redder than red back over into blue.
I wonder if a UV source would show up as red for the same reason.
I don't have a UV source to try this.

I don't have a web cam for comparison, so still using the cell camera.

I've been racking my brain for a UV source. It dawned on me, I had an old UV windowed eprom eraser. There's no filter over the tube. My samsung verizon cellphone camera picks up the light and displays it as saturated white surrounded by pale blue. The direct TV remote has a very dark red lense over the LEDs. On closer inspection, the LEDs are displayed as saturated white, and what I percieve as a surrounding pale red halo, itself surrounded with a pale blue halo.

I should add that I've been placing the camera too close to focus.
 
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  • #11
Phrak said:
I've been racking my brain for a UV source. It dawned on me, I had an old UV windowed eprom eraser. There's no filter over the tube. My samsung verizon cellphone camera picks up the light and displays it as saturated white surrounded by pale blue. The direct TV remote has a very dark red lense over the LEDs. On closer inspection, the LEDs are displayed as saturated white, and what I percieve as a surrounding red halo, itself surrounded with a blue halo.

My IR shows saturated white to dark blue depending on how much I attenuate the beam.
Didn't notice any haloing effect that I can see. The image on the PC is fairly large compared to a cell phone.
I have a few UV sources, like your eprom eraser, but they all produce far to much visible light.
 
  • #12
LURCH said:
BTW, have you thought of using an optical fiber to contain the beam?

No, haven't thought about it at all...please give any suggestions that you may have.
 
  • #13
I know the time from the past thread has been a little bit, but thought I would continue this...

Does anyone know of any low price suppliers of laser pointers? I googled them and got all kinds of stuff I wasn't looking for... I thought I remembered seeing nice single point lasers on the boardwalk for like $5...where'd they all go?
 
  • #14
Can you explain more about what you are trying to do? I thought you were using IR ... laser pointers are generally visible light. What about a simple lens and an LED (IR or visible)?

Anyway, I see laser pointers at my local Ace Hardware store for around $5 or $10.
 

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