--- In SkunkworksAMA_at_yahoogroups.com, Scrapper Black Dragon
<scrapperbd_at_y...> wrote:
> --- Tethasandry J'kress <tethas_at_s...> wrote:
> > Every moniter is different slightly, even the same make
> > and model #...
> In this case it a dodgey old CRT system that was probably
> set dim to avoid 'flame out'. Hence when viewed on either
> of the other systems both of which have TFTs. No, they are
> NOT LCDs; LCD is like a digital watch and can't do colour!
>
> > Through, it does look a little
> > blue to me...so our moniter settings are likely close to
> > the same.
> I 'fixed' the pic on the dark monitor, hence it is now too
> light on a 'more correct' screen.
>
> > Doesn't look bad at all however.
> Thank-you; we aim to please. :-)
>
> Incidentally, those 'flat panel' monitors, despite what you
> may see advertised etc, are NOT LCD (Liquid Crystal
> Display). Liquid Crystal only comes in one colour - black.
> Tiny magnetic particles are polarised to form an opaque
> surface between two thin sheets of glass. 'Colours' in
> watches with LCD screens are background colours that are
> obscured by the black liquid crystal when it is 'on'. The
> monitors are TFT (Thin Film Transistor); like tiny LEDs
> (Light Emitting Diodes) all bunched together. Some of the
> real big 'monitors' can be plasma that uses a modified CRT
> (Cathode Ray Tube) system - like many tiny monitors joined
> together, each the size of one pixel.
>
> So feel free to call them 'flat panel', but please don't
> call them LCD!
>
> Scrapper, Black Dragon, picky with his technology terms.
>
Ouch, I detect a good amount of anger about this subject. Chances
are I may fuel it, though I hope this explanation may help to soothe
it next time you come across a monitor advertised as LCD.
It's true that LCDs cannot produce color. A passive LCD pixel can
either block light or let it pass through, which is what you'd find in
inexpensive displays on watches, radios and various appliances. An
active LCD pixel can allow light to pass in varying degrees. This is
where TFTs come into play (actually, there's also a capacitor for each
transistor but it probably would've made the name clunky so it's
played down). The TFT circuit allows the LCD pixel to display a
greyscale of 256 shades, which would make a nice monocrome display. We
want color, so the pixel count is upped by a factor of three and a
tinted layer is placed above each one. They are also scaled down so
three rectangular subpixels fit into the space of one real pixel (they
are really small, so chances are you'll need a magnifying glass to see
them, but they are there).
So to make one of today's common flat-panel screens, both LCD and TFT
is needed. A pure LCD monitor would be a boring sight and purely TFT
would be no sight at all. :)
Other technologies are SED (very interesting, but not mass-produced
for at least another year), OLED (need more work, before it can be
used in large, long-lived displays) and plasma (flawed, but put into
production anyway), all of which are lightsources by themselves and so
does not need to be backlit like current LCD displays.
Uh, also, I'd better point out that LCDs are not based on magnetism.
The current passed through the crystal layer causes it to twist and go
out of alignment with the polarised layers of glass and hence block
light from passing. Removing the current snaps the crystal back into
alignment. There's a lot more to it that just this, but if that level
of detail is desired it can easily be looked up.
Regards,
-pawtuxet
Received on Wed Oct 06 2004 - 09:42:27 CDT