14380RE: [SeattleRobotics] Re: Laser Diodes from Laser Printers?
- Aug 2, 2003Well, I stand corrected - if these are near-IR lasers.
Of course all this begs the question of beam shape. A 1mW, collimated beam
pointed directly into the eye is a lot different than the amount of energy that
enters the pupil from a widely divergent source way past the focal point of the
lens. Aren't these printers focusing the beam to a very small point at very
close distances? That beam pattern has to be highly non-collimated and fairly
large at any significant distance from the laser.
We used to get annual "LASER-eye exams" until they discovered that flashing a
retina through a dilated pupil with enough light to take a photograph was much
worse for the eye compared to the chance of injury from any of our equipment. I
still think the danger is over-blown for legal reasons (OSHA regs included), but
better safe than sorry - play with at your own risk.
Anyway, I prefer LEDs and visible ones at that, primarily because you can "see"
where the light is impinging.
Laser light in the visible to near infrared spectrum
(400 - 1400 nm) is *focused* by the eye onto the retina.
These wavelengths are known, in laser eye safety literature,
as the "retinal hazard region".
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