<br><font size=2 face="sans-serif">Dear Julia,</font>
<br>
<br><font size=2 face="sans-serif"> </font><font size=3>your
question: "Firstly, do Liquid Crystal Display TV or computer monitors
emit any ionizing radiation? "</font>
<br>
<br><font size=2 face="sans-serif"> CRT
computer monitors emit a small amount of radiation. LCD display do not
emit radiation (beyond light).</font>
<br>
<br><font size=2 face="sans-serif">from http://en.wikipedia.org/wiki/Cathode_ray_tube</font>
<p><a href=http://en.wikipedia.org/wiki/Ionizing_radiation><font size=3 color=blue><b><u>Ionizing
radiation</u></b></font></a><font size=3><b>:</b> CRTs emit a small amount
of </font><a href="http://en.wikipedia.org/wiki/X-ray"><font size=3 color=blue><u>X-ray</u></font></a><font size=3>
band radiation as a result of the electron beam's bombardment of the shadow
mask/aperture grille and phosphors. Almost all of this radiation is blocked
by the thick leaded glass in the screen, so the amount of radiation escaping
the front of the monitor is widely considered harmless. The </font><a href=http://en.wikipedia.org/wiki/Food_and_Drug_Administration><font size=3 color=blue><u>Food
and Drug Administration</u></font></a><font size=3> regulations in 21 </font><a href=http://en.wikipedia.org/wiki/Code_of_Federal_Regulations><font size=3 color=blue><u>C.F.R.</u></font></a><font size=3>
</font><a href="http://frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?YEAR=current&TITLE=21&PART=1020&SECTION=10&SUBPART=&TYPE=TEXT"><font size=3 color=blue><u>1020.10</u></font></a><font size=3>
are used to strictly limit, for instance, television receivers to 0.5 milliroentgens
per hour (mR/h) (0.13 µC/(kg·h) or 36 pA/kg) at a distance of 5 cm from
any external surface; most CRT emissions fall well below this limit </font><a href="http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=1020.10"><font size=3 color=blue><u>[1]</u></font></a><font size=3>.</font>
<br>
<br><font size=3>Your question "If the LCD screen becomes damaged
through the inadvertent use of the wrong typed of cleaner or by using any
abrasive cloth could it expose one to increased ionizing radiation?"</font>
<br>
<br><font size=3>No. </font>
<br>
<br><font size=2 face="sans-serif">In a LCD display damaging the display
results in poor viewing of the liquid crystals. You can only make
the display murky or dim by using an abrasive on the screen and over-cleaning
it...</font>
<br>
<br><font size=2 face="sans-serif"> http://en.wikipedia.org/wiki/Lcd_display</font>
<br>
<br><font size=2 face="sans-serif">There is a small fluorescent light in
a display but it is very safe. All fluorescent lights need a mechanism
to ionize the plasma to make the fluorescent tube light up. The usual methods
involve electrons (beta radiation) and those are low energy. </font>
<br>
<br><font size=2 face="sans-serif"> http://en.wikipedia.org/wiki/Fluorescent_lighting</font>
<br>
<br><font size=2 face="sans-serif">There are occasional lighting methods
that can have a health issue. This was more common in the past with
radium paint, and less so today with tritum lighting. </font>
<br>
<br><font size=2 face="sans-serif">http://en.wikipedia.org/wiki/Self-powered_lighting</font>
<br><font size=2 face="sans-serif">------<br>
Sincerely,<br>
<br>
Tom Pierce<br>
</font>
<br>
<br>
<br>
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<td width=40%><font size=1 face="sans-serif"><b>"julia howard"
<juliarachelhoward@googlemail.com></b> </font>
<br><font size=1 face="sans-serif">Sent by: beowulf-bounces@beowulf.org</font>
<p><font size=1 face="sans-serif">05/25/2007 03:14 PM</font>
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<div align=right><font size=1 face="sans-serif">To</font></div>
<td valign=top><font size=1 face="sans-serif">beowulf@beowulf.org</font>
<tr>
<td>
<div align=right><font size=1 face="sans-serif">cc</font></div>
<td valign=top>
<tr>
<td>
<div align=right><font size=1 face="sans-serif">Subject</font></div>
<td valign=top><font size=1 face="sans-serif">[Beowulf] cold cathode fluorescent
backlighting</font></table>
<br>
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<tr valign=top>
<td>
<td></table>
<br></table>
<br>
<br>
<br><font size=3>Not having an Electronics background my questions may
seem naive. However as the following issues give me concern I should
very much appreciate it if they could be sorted out with some reliable
knowledge. <br>
<br>
Firstly, do Liquid Crystal Display TV or computer monitors emit any ionizing
radiation? <br>
I f the LCD screenbecomes damaged through the inadvertent use of the wrong
typed of cleaner or by using any abrasive cloth could it expose one
to increased ionizing radiation?<br>
<br>
Regarding the cold cathode fluorescent backlights of monitors I read in
the Wikipedia encyclopedia under Cold Cathode that some ccfls use a source
of beta radiation to start the ionization process. I f this is the case
then could LCD televisions expose us to beta or gamma radiation. I should
like to replace my CRT TV with a LCD TV, but the thought of a radioactive
material being present causes me much anxiety. <br>
<br>
Looing forward to your informed response,<br>
<br>
Julia Howard<br>
email: </font><a href=mailto:juliarachel_howard@yahoo.co.uk><font size=3 color=blue><u>juliarachel_howard@yahoo.co.uk</u></font></a><font size=2><tt>_______________________________________________<br>
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