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LCDs Vs CRT

 
 
Bret
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      08-19-2003
On Tue, 19 Aug 2003 16:06:22 +1200, "Howard Johnson" <(E-Mail Removed)>
wrote:

>
>"Russell Smithies" <(E-Mail Removed)> wrote in message
>news:5Og0b.120636$(E-Mail Removed).. .
>>
>> "back again" <(E-Mail Removed)> wrote in message
>> news:Xns93DC9CC23FC90backnowherecom@130.133.1.4...
>> > Allistar <(E-Mail Removed)> wrote in
>> > news:nef0b.12360$(E-Mail Removed):
>> >
>> > > Subject: Re: LCDs Vs CRT
>> > > From: Allistar <(E-Mail Removed)>
>> > > Newsgroups: nz.comp
>> > >
>> > > back again wrote:
>> > >
>> > >> I know CRTs spit out some nasty types of energy, but wondered whether
>> > >> LCD displays spit out any junk too - eg., ultra violet. Does anyone
>> > >> here know?
>> > >>
>> > >> Cheers,
>> > >> Mark
>> > >
>> > > What sort of nasty energy do CRTs spit out?
>> >
>> >
>> > X-Rays for a start. I don't know if other wavelengths (UV) also make it
>> > though the glass, I assume so though.
>> >
>> >
>> > > All it spits out is
>> > > electromagnetic radiation (as visible light out the front and possibly
>> > > some out the back).
>> >
>> >
>> > Nope. CRTs also spit out crap outside the visible spectrum too.
>> >
>> >
>> > > LCDs also emit electromagnetic radiation as well
>> > > (they would be pretty useless if they didn't).
>> >
>> >
>> > I am interested in whether LCDs emit _damaging_ types of radiation (eg.,
>> > UV) as opposed to for example visible spectrum. I'm also interested in
>> > whether the amount if any of damaging rays are so low as to be

>equivalent
>> > (for example) that standing outside for 5 minutes would results in a
>> > similar level of exposure to 8 hours LCD usage.
>> >
>> >
>> > > Allistar.
>> >

>>
>>
>> Latest "Atomic" magazine has a nice comparison of how much nasty radiation
>> comes from various comp related gadgets.
>> IIRC monitors 'leak' most from the rear and sides.
>>
>> Russell

>
>Well that would make sense.
>They have a big metal shadow mask at the front
>Much like the door on a microwave oven
>A good quality heavy duty tinfoil hat should protect you at the rear and
>sides.
>Be sure not to expose your gonads close to one of these devices.
>There has been a worldwide drop in fertility due to meatbeating in the
>presence of CRTs
>(Thats why woger switched.)
>

ROTFL
 
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Anybody
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      08-19-2003
In article <bhrt4n$v3h$(E-Mail Removed)>, "Rupert"
<(E-Mail Removed)> wrote:

> > I know CRTs spit out some nasty types of energy

>
> no they don't


EVERYTHING spits out "nasty energy" to some degree, especially
electronic equipment.

CRT screens throw out most of their "nasty energy" from the back and
the sides (as someone else said), partyly because the glass tube acting
as a shield. If you don't like your next door co-worker then trun the
monitor so that the back end points at them.

LCD screens still throw out "nasty energy", but levels are *SAID* to be
better for you than a CRT. Now, as we all know, the so-called
"experts" who make these claims are always changing their minds, so
talk it with a HUGEMUNGOUS pinch of salt (a large portion of these
claims are probably just the marketing guys trying to get you to buy
the more expensive LCD monitors).
 
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back again
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      08-19-2003
"Uncle StoatWarbler" <(E-Mail Removed)> wrote in
news(E-Mail Removed):

> The light in a LCD is a cold cathode flourescent. There would be some
> UV coming out, but as UV cooks LCDs in short order I expect there are
> heavy filters on the back of the display to prevent that happening.


That matches my suspicions - thanks
 
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Ross Dawson
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      08-19-2003
On 19 Aug 2003 03:24:31 GMT, back again <(E-Mail Removed)> wrote:

>Allistar <(E-Mail Removed)> wrote in
>news:nef0b.12360$(E-Mail Removed):
>
>> Subject: Re: LCDs Vs CRT
>> From: Allistar <(E-Mail Removed)>
>> Newsgroups: nz.comp
>>
>> back again wrote:
>>
>>> I know CRTs spit out some nasty types of energy, but wondered whether
>>> LCD displays spit out any junk too - eg., ultra violet. Does anyone
>>> here know?
>>>
>>> Cheers,
>>> Mark

>>
>> What sort of nasty energy do CRTs spit out?

>
>
>X-Rays for a start. I don't know if other wavelengths (UV) also make it
>though the glass, I assume so though.
>
>
>> All it spits out is
>> electromagnetic radiation (as visible light out the front and possibly
>> some out the back).

>
>
>Nope. CRTs also spit out crap outside the visible spectrum too.
>
>
>> LCDs also emit electromagnetic radiation as well
>> (they would be pretty useless if they didn't).

>
>
>I am interested in whether LCDs emit _damaging_ types of radiation (eg.,
>UV) as opposed to for example visible spectrum. I'm also interested in
>whether the amount if any of damaging rays are so low as to be equivalent
>(for example) that standing outside for 5 minutes would results in a
>similar level of exposure to 8 hours LCD usage.


If that's the case me thinks you need to get out more

--
Cheers for now

Ross Dawson.
 
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Henry Falkner
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      08-20-2003


"Allistar" <(E-Mail Removed)> wrote in message
news:nef0b.12360$(E-Mail Removed)...
> back again wrote:
>
> > I know CRTs spit out some nasty types of energy, but wondered whether

LCD
> > displays spit out any junk too - eg., ultra violet. Does anyone here

know?
> >
> > Cheers,
> > Mark

>
> What sort of nasty energy do CRTs spit out? All it spits out is
> electromagnetic radiation (as visible light out the front and possibly

some
> out the back). LCDs also emit electromagnetic radiation as well (they

would
> be pretty useless if they didn't).
>
> Allistar


Cathode Ray Tubes use accelerated electron beams, which are converted to
light by the phosphor coating on the inside of the front glass. There are
three beams in colour tubes, hitting blue, green and red phosphors. A metal
'mask' insures that the right beam hits the right coloured phospors. This
mask also protects the viewer to some extent. But the beams are scattered by
the same mask. CRTs have metal boxes round the 'electron guns' at the back
these days. This reduces 'stray radiation'.

Radio amateurs complained for years that CRTs are jamming transmitters. It
was not considered commercially viable to do something about it. But when
office girls began to worry about their health, suddenly the screening of
CRTs became commercially feasable.

The light is not the main problem. But because of the acceleration, the
electron beams have the ability to 'ionise', that is knock electrons out of
their orbits around atoms. This makes the atoms 'charged'. The body does not
like too many of its atoms charged. It is one method by which genetic
information is more likely to alter spontaneously.

Liquid Crystal Displays are either passive arrangements of variable Liquid
Crystal filters, but mostly 'active' these days, that is, they have light
emitting transistors behind the Liquid Crystal filters. But there are no
'rays' ionising anything. Also because there is no energy required to
accelerate electrons in the way CRTs do, Liquid Crystal Displays need less
power than CRTs.

From a radio point of view, the computers themselves are still jamming
transmitters, because they work in the same 'bands' that radios work in,
which is why air lines don't like people using computers on their planes
terribly much. So, manufacturers have to 'screen' laptops all over, like
they have to do with CRTs, so people are allowed now to use laptops once the
planes are airborne.

This also helps radio amateurs like myself, who use a laptop to convert
pictures into sound for transmitting, then convert the sound back into
pictures again after it has been received. Laptops are a lot quieter on the
radio bands than desktop computers are.

And with far less unwanted radiation coming out of a laptop, they are also
better for your health.

Henry


 
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