[Beowulf] cold cathode fluorescent backlighting

duane at duaneberry.net duane at duaneberry.net
Thu Jun 28 03:29:58 PDT 2007

> 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.

Even naive questions are a quest for knowledge and therefore honorable.
[Even if they are a bit off-topic ;) ]

Executive summary:
  You have nothing to worry about.

  For a truly informed opinion look for the list of approving authorities
that must be clearly visible on each device. In the USA that would be
the FCC and the UL. Other countries have their own equivalents. The
standards they use for testing should be publicly available and include
radiation metrics if applicable.

                        Primer on Radiation

  Alpha and Beta "radiation" are actually particles like neutrons. These
are the most dangerous forms of radiation BUT they are also the easiest
to stop. If I remember arightly Alpha can be stopped by a sheet of paper
and Beta is blocked by normal clothing.
  Gamma radiation (aka X-rays) is true radiation and requires some thing
like lead shielding to stop. This is why an X-ray technician steps
behind the lead shield or leaves the room after they get the film and
the emitter positioned around your body.

*** NOTHING *** in the world of consumer electronics, including computers
and peripherals, emits Gamma radiation.

> Firstly, do Liquid Crystal Display TV or computer monitors emit any
> ionizing radiation?

  For CRT's there has been long debate, for LCD's no.

> If 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?


> 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. If 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.

  Even if a beta source inside a monitor/TV was continuously emitting the
physical  construction would provide more than enough shielding. For
power and regulatory considerations I doubt the source is on

  IMHO moving from CRT to LCD is a good move in general.

  Wikipedia is a good source of keywords for use in further research. I
would not consider Wikipedia an authoritative source of information on
it's own.

> Looing forward to your informed response,
> Julia Howard
> email: juliarachel_howard at yahoo.co.uk
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