I am looking for the right acrylic lens. Since will be buying at least 1000 pieces I don't want to make any mistake.

I want to concentrate the signal from IR LED in a 1cm diameter tube at one point 20cm in diameter. From what I know, IR LEDs disperse the beam too widely, hence the need for a lens. What shape of lens should I buy? Are there any online resources that could help me

The distance between wall and led is 5-10m. Size of LED is the standard one I guess 5mm. Wave length is 970nm.


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    \$\begingroup\$ No help on the optics question, but I would definitely get a sample or similar item from another supplier (Edmund? Thor?) before buying 1,000 pieces. You might want to link the proposed LED datasheet- different parts will have different "viewing angles" (radiant intensity vs. angular displacement charts). \$\endgroup\$ Commented Nov 15, 2014 at 18:14
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    \$\begingroup\$ You need physics.se \$\endgroup\$ Commented Nov 15, 2014 at 18:34
  • \$\begingroup\$ Thank you both :) I already posted it on physics, should I delete it from here? \$\endgroup\$ Commented Nov 15, 2014 at 18:46
  • \$\begingroup\$ @OndrejTokar You will need to specify how far the LED is from the wall, and the diameter of the LED. It's basically an optics question. \$\endgroup\$ Commented Nov 16, 2014 at 10:08

1 Answer 1


You'll need to know the LED's beam angle and wavelength, the distance to the wall and the spot size on the wall, and then you can get ahold of the folks at Fresnel Technologies for help.

They make plastic Fresnel lenses and can help you out with the optics and materials to use for your application.

I used them to supply me with lenses for a long-distance PIR project and was well satisfied with their performance.

BTW, here's some interesting reading.


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