GRYNX

8th 2005f June, 2005

Part 2 – New IR LED

by @ 11:26. Filed under
  Use your webcam in the dark.
– Part 2
 
  Finding a better light source

Last update: 2005-04-14

 

From this in normal light (without IR filter)


 

to this in total darkness


 

to this with two different IR LED types


Note – You can click on all pictures to see a full size version


The problem


The solution

The components


The result


Disclaimer

The problem

So, in part 1 I tried to use 10 regular IR LED’s (CQY99) as illumination for my modified Philips PCVC740k webcam. It did work well, but using 10 LED’s takes up a lot of space, at the same time as they’re not that efficient. So can we do this better? I looked trough all IR LED’s at my preferred supplier (Elfa in Stockholm), and came up with one LED that was interesting. (By the way, Elfa ships all over the world, but I’m sure that you can find a similar supplier in your country)

The solution

So, I found a LED called HSDL-4220 with a brother called HSDL-4230. The difference between these are the angle of the emitted beam. The 4220 emits a 30° beam while 4230 emits a 17° beam. And the 4220 emits 38mW/sr while 4230 emits 75mW/sr, where the difference is due to the angle of the beam. Electrically they’re the same. The datasheet for them is here.

The continuous electrical specifications for them are 875nm centre, max 100mA, 1.5V. At a 100mA the 4220 delivers 76mW/sr and 4230 delivers 150mW/sr (in the middle that is). The LED emits a small amount of red light when running on 50 and 100mA.

Now, let’s have a look at the test rig and the pictures of the emitted light from the IR LED’s.

The components

I’ve used a similar setup as in the first part as this will enable me to experiment with the values more flexibly.

As you can see the 4230 really lights up, and I got very exited about it when I first took this picture.

Next, let’s have a result with all the test projections will the different IR LED’s.

The result

So, what’s the conclusion?

Of first the 4230 (17° beam) I actually were a bit disappointed. The beam is so focused that in my 1.5m test setup I got circles on the wall.

1*4230 100mA

 

 

3*4230 100mA all focused in the middle


 

2*4230 50mA each


3*4230 100mA focused on three points


As you can see there is nothing wrong with the intensity in it self, but the way it looks (!) makes it unusable for my needs.

As for the 4220 the results were a..lot..better..

1*4220 100mA


3*4220 100mA


10*CQY99 20mA


Even only one 4220 LED outperforms the 10* CQY99 that I used earlier. And I guess that I could get ever smoother results on the three 4220 if a managed to focus them a little more spread, but I’ll do that some other time…

By the way, I noticed a smooth headache coming on while doing these experiments! You might want to avoid looking into the LED’s as I really doesn’t know if it good or bad for you. After all 3*4230 at 100mA generates 450mW of light that your eye can’t protect itself from.

If you know anything about it then drop me a email, before I loose my eyesight :(

 Note. Looking into an IR light source might (?!) damage your eyesight. I don’t take any responsibility for any personal damages, but hey, I can still see good :) (or at least I’m under that impression.)


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27 Responses to “Part 2 – New IR LED”

  1. Joe Eckstein Says:

    “hey, I can still see good :) (or at least I’m under that impression.)”
    *as he crashes into the doorjam on the way out of his office*

  2. computerxpert Says:

    hmmm. i think IR does do somthing to your eyes, i have forgotten what though. I think its to do with radiation.

  3. Oscar Says:

    Chris:
    It looks like if you were making your experiments in total darkness, so probably
    the problem with your headache comes from your eye trying to catch light where there
    is not. Your iris makes efforts, wide open, to let pass light that doesn’t arrive,
    so the wear is reflected in headache. As you remark in your text, it is not a good
    idea looking straight into a lit LED like the one you’re using (no one would make
    it in a pointer LASER, I think), for the emitted power is so great that it could
    be dangerous for retina integrity.
    My best wills to your investigations, which I hope you’ll get on…

  4. hans Says:

    I got this from searching within PubMed

    Cataracts occur frequently among workers who deal with hot material such as molten glass or steel, as a result of exposure to intense infra-red radiation (i.r.) emitted from it.

    It is suggested that i.r. cataracts in the workplace result from the generation of heat by absorption of i.r. in the cornea and heat conduction to the lens.

    This absorbtion depends on the emitted power from the IR led over the surface area of your retina.

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  7. seb Says:

    I don’t think this kind of IR could be dangerous for your eyes. UV makes you blind not IR, that’s why we wear sunglasses.

    Most of camera are using IR for their auto-focus system, and I never heard about people getting blind because of this.

  8. Chris Says:

    Hmm, I guess you have a point! Thanks!

  9. NoviceScotty Says:

    Hi – my work involves infra-red lasers, and I can tell you the following:
    1) Near Infra-red causes burns to the retina at high powers.
    2) The problem is that the blink reflex doesnt work with IR, so you dont realise you’re getting burnt
    3) IR lasers are generally considered to be eye safe for powers below 1mW
    4) IR Lasers above 5mW are considered definitely an eye hazard

    So I would recommend being careful, and not looking at the LED at close range –
    at larger distance the beam spread means that not all the energy enters your eye,
    but at short distances you could do yourself permanent damage.
    (A laser is just a LED with much tighter beam spread, and so all the laser light can enter the eye
    at large distances. )

    Treat it the same way as you would a high-power white LED – you wouldn’t stare into that would you!

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  11. Amber Says:

    It looks like if you were making your experiments in total darkness, so probably
    the problem with your headache comes from your eye trying to catch light where there
    is not. Your iris makes efforts, wide open, to let pass light that doesn’t arrive,

  12. Megan Says:

    I can still see good (or at least I’m under that impression.)”

  13. backgammon Says:

    Hi – my work involves infra-red lasers, and I can tell you the following:
    1) Near Infra-red causes burns to the retina at high powers.

  14. tramadol Says:

    Most of camera are using IR for their auto-focus system, and I never heard about people getting blind because of this.

  15. Mark Says:

    Hi,

    I would definitely say that it isn’t intelligent to look into lit LED’s.

    Otherwise, thanks for the great project, just what I have been looking for.!

  16. tramadol Says:

    I never heard about people getting blind because of this.

  17. tramadol Says:

    It looks like if you were making your experiments in total darkness, so probably
    the problem with your headache comes from your eye trying to catch light where there
    is not. Your iris makes efforts, wide open, to let pass light that doesn’t arrive,

  18. rxtramadol Says:

    Hi,

    I would definitely say that it isn’t intelligent to look into lit LED’s.

    Otherwise, thanks for the great project, just what I have been looking for.!

  19. backgammon Says:

    I would definitely say that it isn’t intelligent to look into lit LED’s.

  20. backgammon online Says:

    Most of camera are using IR for their auto-focus system, and I never heard about people getting blind because of this.

  21. Backgammon Says:

    It looks like if you were making your experiments in total darkness, so probably
    the problem with your headache comes from your eye trying to catch light where there
    is not.

  22. משחק לוח Says:

    I don’t think this kind of IR could be dangerous for your eyes. UV makes you blind not IR, that’s why we wear sunglasses.

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    Cataracts occur frequently among workers who deal with hot material such as molten glass or steel, as a result of exposure to intense infra-red radiation (i.r.) emitted from it.

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    so the wear is reflected in headache. As you remark in your text, it is not a good
    idea looking straight into a lit LED like the one you’re using (no one would make

  25. jumpjack Says:

    Warning man, IR rays just COOK your eyes!
    Te proof is that you CAN’T use a negative film to protect your eyes while looking at a solar eclipse, as you’ll THINK it’s shielding, as it shields VISIBLE light, but the sun IR will BURN your eye!
    And negative film is what you use to get an IR cam from a standard cam, right?

  26. Jimmy S Says:

    Hi ther my mane is Jimmy. i have installed a few night vision camera in a vets holding room, and the ? has come up about the camara uses Infrared LED for it’s night vision. Are there any long trem problems with being under the LED for a long time frams.. i have not been able to find any info about this can u help???

  27. spiffmds Says:

    “(A laser is just a LED with much tighter beam spread, and so all the laser light can enter the eye
    at large distances. )”

    Not to nitpick, but a laser is very different than an LED. A laser emits coherent, virtually monochromatic light, while an LED emits over a broad frequency range. Some lasers are based on LEDs (i.e. diode lasers), but are also based on many other materials (dye lasers, rubies etc.).

    I would guess that lasers at the right wavelength would be more dangerous than leds not only because all the energy is focused in a narrow spatial range, but also in a narrow wavelength range.

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