Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84; site petrus.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!gamma!epsilon!zeta!sabre!bellcore!petrus!karn
From: karn@petrus.UUCP (Phil R. Karn)
Newsgroups: net.audio
Subject: Re: cleaning cd-player optics
Message-ID: <412@petrus.UUCP>
Date: Sun, 21-Jul-85 00:32:05 EDT
Article-I.D.: petrus.412
Posted: Sun Jul 21 00:32:05 1985
Date-Received: Mon, 22-Jul-85 07:23:49 EDT
References: <696@charm.UUCP>
Organization: Bell Communications Research, Inc
Lines: 22

> The laser only has a few
> mW of power, which is safe to look in the eye.  Only on Star
> Trek are little lasers powerful enough to really blow
> things away.

A correction on this point: milliwatt lasers are definitely NOT safe to look
in the eye! A compact disc player is generally a Class 1 Laser Product.
While this is low power as lasers go, the energy densities that can be
achieved by focusing even a weak laser are spectacular. Since the laser
operates in the infrared, its radiation is invisible and therefore even more
hazardous.

Fortunately, the depth of focus of a compact disk laser is extremely small
(typically 4 micron -- this is how surface scratches are defocused), small
in diameter (typically 1 square micron) and very close to the lens. In
addition, the physical design of a typical player, along with various
interlocks, makes it rather unlikely that any light will leak out of a
typical player, so in practice there's nothing to worry about unless you
disassemble your player, defeat the interlocks and hold your eyeball up to
the lens.

Phil