View Single Post
  #7   Report Post  
Posted to sci.electronics.repair
Arfa Daily Arfa Daily is offline
external usenet poster
 
Posts: 6,772
Default LCD H - Lin ...?


"hr(bob) " wrote in message
...
On Oct 18, 6:11 pm, " wrote:
On Oct 18, 4:44 pm, "Arfa Daily" wrote:





"Dave Platt" wrote in message


...


Anyone else ever seen this effect on an LCD display, or have any
thoughts
on
how it could occur ?


Might the screen have been an LCD, or a CRT, which "bounces" the image
onto a translucent display screen via a mirror or lens arrangement of
some sort? All sort of opportunity for linearity and misalignment
issues with that sort of arrangement.


--
Dave Platt AE6EO


No evidence of any kind of 'line structure' on the display Dave, so I
don't
think that it was any kind of CRT display, direct or indirect. It was
just a
typical flat panel display on a bulkhead wall, the other side of which
was a
toilet. As well as these main bulkhead displays (there were several
throughout the length of the aircraft) there were also 'repeater'
displays
suspended from the cabin ceiling at regular intervals over the left and
right aisles. These were definitely small LCDs and were perfectly linear
in
both axes, which rules out there being any intrinsic non linearity in
the
original picture before it was placed on whatever media was used onboard
the
aircraft. It's a strange one, for sure ...


Arfa


I have seen this, and stranger effects, in LCD sets. For instance,
I've seen the image "fold-over" on the right side of the screen as if
it's hitting the inside of the CRT, but much more subtly, confined to
about 1/4" of the picture. I always figured it was some sort of
phenomenon arising from the A-to-D of the analog input signal, but I
don't even know if that's possible. I'd also be interested in hearing
what others think of this.- Hide quoted text -

- Show quoted text -


Was only the one bulkhead display non-linear? Did you get a chance to
see the bulkhead display on the other side of the plane? I've
traveled a lot over the years and seen minor non-linearity, but all
the LCD displays were always equal and so it was the source. LCD's
should by their very nature be linear unless the digital electronics
are "counting" wrong.

My thoughts exactly, Bob, which is why I am having so much trouble getting
my head around this one. As to other displays being like it, there was only
one more bulkhead one in front of me, right at the front of the cabin just
before business class, and then there was another in there with them, which
I couldn't see - remember that this was a crappy little 767 that Delta had
put on in place of the wide-bodied plane that we should have been on, and
which would have had individual seatback LCDs. The 767 has a 2 - 3 - 2 seat
configuration, so only large bulkhead displays up the middle. (In defence of
the aircraft though, I have to say that it was very quick - 7hrs 22m across
the Atlantic - and the leather seats were very comfortable). Anyways, the
display right at the front wasn't close enough to see in detail, but the
repeater screens over the aisles certainly were, and as I think I said
elsewhere, these were perfectly linear in both axes, which I feel eliminates
the source signal as being in error in any way.

Arfa