Path: utzoo!utgpu!radio.astro!helios!dooley
From: dooley@helios.toronto.edu (Kevin Dooley)
Newsgroups: comp.sys.mac
Subject: Re: Radiation from the Mac screens?
Summary: there is no significant radiation
Keywords: radiation, protection
Message-ID: <837@helios.toronto.edu>
Date: 3 Jul 89 15:52:29 GMT
References: <134@nisca.ircc.ohio-state.edu> <4400004@macknife> <29836@ucbvax.BERKELEY.EDU> <1509@bucket.UUCP>
Reply-To: dooley@helios.physics.utoronto.ca (Kevin Dooley)
Distribution: comp.sys.mac, sci.physics
Organization: University of Toronto Physics/Astronomy/CITA
Lines: 52

In article <1509@bucket.UUCP> johnw@bucket.UUCP (John Wong) writes:
>In article <29836@ucbvax.BERKELEY.EDU>, thom@dewey.soe.berkeley.edu (Thom Gillespie) writes:
>> Don't mean to disturb anyone but I was wondering if anyone has measured any
>> radiation coming from a Mac screen?
>> 
>> Are there any screen sheilds for Mac screens?
>> 
>
>There is a screen available for PC's, I believe, called Vu-Pro-Tek that
>blocks radiation.  It's expensive (>$200).  It may be adaptable for the Mac.
>
>Laptops that use LCD technology, rather than CRT, I suspect, would be
>safer in that there isn't a high voltage electron gun firing behind
>the tube.  One selling point for the new Macintosh laptop...
>
>John.
>
>tektronix!tessi!bucket!johnw

    There is already an extremely effective radiation shield on your
monitor.  It is called the screen.  The highest energy that an
electron hitting the glass can possibly have is ~20keV.  This means
that the highest energy x-ray that can be produced is ~20keV.  These
x-rays have to pass through a huge chunk of glass (the screen).
The radation which does make it through is very soft and its intensity
is considerably less than what you would measure coming from a large
chunk of cement.  If somebody markets a radiation screen for computer
monitors, they are running a scam.  If the glass were not enough to
filter out practically everything, then you would probably have to use
lead (which makes reading the old screen kind of difficult).

      Now, having said that, let me add one caveat.  There is a fair
amount of radio frequency radiation (non-ionizing, very very low energy)
coming from a computer monitor.  Many people have claimed that prolonged
exposure to rf radiation can be a health risk, although there is no
evidence to support this claim.  It is commonly accepted that the
principle health problems associated with the use of video displays
are:
   - back and neck pain associated with poor posture, poor positioning
     of the monitor and keyboard relative to the body, and uncomfortable
     chairs.  
   - eyestrain resulting from improper lighting, glare and just plain
     staring at those tiny phophor dots to 8 hours at a crack.

    Common sense tells you that the best way to avoid these problems
is to take frequent breaks.  For more information contact the Ministry
of Labour.

-- 
 Kevin Dooley         UUCP - {uunet,pyramid}!utai!helios.physics!dooley
 Physics Dept.        BITNET - dooley@utorphys
 U. of Toronto        INTERNET - dooley@helios.physics.utoronto.ca