White LED and heachaches

I was excited to see a Coast LED Lenser Tac Torch at our local Costco. I picked up four at $29.00 each. It takes 3 AAA instead of something less common and puts out 117.6 mW. It's brighter than my 2-D maglite.

Here's the issue: After I use the flashlight around the house or outside, even for only a few minutes, I feel a headache comming on especially behind my eyes. (No, I've never looked directly at the light) I'm not expecting any medical diagnosis here as I am healthy man, but I am wondering if the wavelengths of these LED white lights are not good for the human eye. Can these lights be used for everyday uses or are they designed to blind people/suspects ie: in police work?

Any thoughts would help as I am trying to decide whether to keep them or return them and stick to my old Maglite which is still going strong after ten years.

Thanks everyone.

Chris
Northern CA

Don't know about the your condition with them bright white LEDs. Maybe just having your eyes take some time to get used to it.

Anyways, Welcome to CPF!

It could be my imagination, but I think I've noticed something similar with bright blue LEDs. Seems like this topic came up before long ago.

Geoff

Hmm. Only headache I get is when I wear glasses and not contacts. My poor sides of my head have dents in them!

Some people might be more suspetible, as a royal blue mag mod does not bother me one bit.

Is the tint on those very blue? I tend to get headaches whenever I'm using light which is too far from white, although in my case yellow (incandescent) light is what really bothers me. I just find the blue-tinted LEDs a bit unpleasant rather than headache-inducing like incandescent and especially candle light.

The light does not appear to be blue to me. I just shone it on our white walls and it seemed pretty white to me. Is there a better way to tell?

Chris

I know someone who has a computer (HP I think) that has very bright blue LED's illuminating logos on the tower and monitor. When the room is dark, it hurts my eyes to try to focus on the logos, and I get a little bit of a headache if I look at them for too long. In my case, I think it is the aura coming off the logos that obscures their edges and makes it hard to focus my eyes that causes the headache, and not the wavelength. It doesn't sound like this is the problem you are having though.

Your problem could be that your specific LED has an odd tint as a component of the white that it emits that is causing irritation.

sonko2010 said:

The light. . .seemed pretty white to me. Is there a better way to tell?

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Do you have another LED that you can compare it to? That way you can "see" the differences in hue, varying from one LED to another LED.

bexteck said:

I know someone who has a computer. . .that has very bright blue LED's illuminating. . .it hurts my eyes to try to focus on the logos, and I get a little bit of a headache. . .I think it is the aura coming off the logos. . .that causes the headache

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Hopefully that doesn't happen with them Alienware computers and those "glowing alien eyes," Blue, Red, or Green.

I'll bet it's because the LEDs are pulse modulated, as part of a voltage regulation circuit.

(This can affect some people, especially epilectics)

Most led circuits seem to use a multivibrator, just wave the torch around and see if you see a continuous line, or disjointed.

(Also wave your fingers vertically in front of your TV...scary )

bexteck said:

I know someone who has a computer (HP I think) that has very bright blue LED's illuminating logos on the tower and monitor. When the room is dark, it hurts my eyes to try to focus on the logos, and I get a little bit of a headache if I look at them for too long. In my case, I think it is the aura coming off the logos that obscures their edges and makes it hard to focus my eyes that causes the headache, and not the wavelength. It doesn't sound like this is the problem you are having though.

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I'm guessing that the blue LEDs are close enough to NUV in wavelength that they're fluorescing your corneas a little bit, and that's causing the haze. I've noticed this effect before.

abvidledUK said:

I'll bet it's because the LEDs are pulse modulated, as part of a voltage regulation circuit.

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I tend to agree, and I'll add that I never really cared for the whole concept of PWM to begin with. We started running fluorescents on electronic ballasts to get rid of flicker, and now it seems a step backwards to take LEDs which run on DC and make them flicker. All we need is for people to get a negative association with LEDs and flicker, and then they won't use them for the same reasons they shunned fluorescents for years.

Flying Turtle said:

It could be my imagination, but I think I've noticed something similar with bright blue LEDs. Seems like this topic came up before long ago.

Geoff

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Normally you can get this fenomen when using to blue LEDs combined with a to narrow light angle.

This is due to that the light contrast is to big comparing the light from the LEDs to the surrounding light.

I guess that you have bigger problems like this using the LED lamp at night than when using the LED lamp at the afternoon.

I get headaches when using Blue LEDs - the Blue LED lights I have are resistored (I built them), no PMW involved.

"white" LED emitters that are off into the blue end of the spectrum have a similar effect on me making me feel slightly dizzy. It's extremely unpleasant for me. Lights that are pulse modulated bother me too. The worst is when the two combine (an older el-cheapo led headlamp I have has both...I can't use it at all).