Ch4 3D Optical Advice
 

David wrote:
"Martin" wrote in message
o.uk...

.......... But how do you make a TV screen produced polarised light
that
the polarised specs can separate into different left and right
images?

Alternate lines could have filters to polarise in the different directions -
although this would waste half of the power, so only generating the right
kind of light would be better, but I don't know if that's possible.

--
We are the Strasbourg. Referendum is futile.

Ch4 3D Optical Advice
 

In article , David
writes


"Martin" wrote in message
news:[email protected] co.uk...

.......... But how do you make a TV screen produced polarised light that
the polarised specs can separate into different left and right images?

2 TV sets, now there is a thought.
LOL
Don't knock it - that's exactly the solution that we used back in the
80s for some of the prototype 3D displays that resulted in some of the
broadcast experiments that were discussed earlier in the thread.

2 TVs behind left & right handed circular polarising screens viewed via
a semi-silvered mirror so that one display was transmitted by the mirror
and the other reflected - thus appearing as a single display. Viewed
with left and right handed circularly polarised glasses the images were
separated again for the viewer.
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's ****ed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)

Ch4 3D Optical Advice
 

In article , Basil Jet
writes
David wrote:
"Martin" wrote in message
o.uk...

.......... But how do you make a TV screen produced polarised light
that
the polarised specs can separate into different left and right
images?

Alternate lines could have filters to polarise in the different directions -
although this would waste half of the power, so only generating the right
kind of light would be better, but I don't know if that's possible.

Wouldn't waste any more power than current LCD sets, which are already
polarised in one direction anyway. Try looking at an LCD display
through polaroid glasses then rotate the glasses and you'll see what I
mean - which is one of the problems with simple polarised filters:
tilting your head while wearing the polaroid specs causes mixing of the
left and right images and loss of the 3D effect.

The solution to that is to use left and right handed circular polarised
light, with similarly circular polarised glasses. That eliminates the
tilt crosstalk effect, but it requires an extra layer on the screen and
on the glasses.
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's ****ed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)

Ch4 3D Optical Advice
 

Kennedy McEwen wrote:
In article , Basil Jet
writes
David wrote:
"Martin" wrote in message
o.uk...

.......... But how do you make a TV screen produced polarised light
that
the polarised specs can separate into different left and right
images?

Alternate lines could have filters to polarise in the different
directions - although this would waste half of the power, so only
generating the right kind of light would be better, but I don't know
if that's possible.

Wouldn't waste any more power than current LCD sets, which are already
polarised in one direction anyway.

I was aware of that, but there is a political and cultural climate of energy
saving now that wasn't around when the LCD screens were introduced.

--
We are the Strasbourg. Referendum is futile.

Ch4 3D Optical Advice
 

In article , Basil Jet
writes
Kennedy McEwen wrote:
In article , Basil Jet
writes
David wrote:
"Martin" wrote in message
o.uk...

.......... But how do you make a TV screen produced polarised light
that
the polarised specs can separate into different left and right
images?

Alternate lines could have filters to polarise in the different
directions - although this would waste half of the power, so only
generating the right kind of light would be better, but I don't know
if that's possible.

Wouldn't waste any more power than current LCD sets, which are already
polarised in one direction anyway.

I was aware of that, but there is a political and cultural climate of energy
saving now that wasn't around when the LCD screens were introduced.

If you were aware that there would be no waste of power, why mention it
in the first place, unless to endorse the political and cultural climate
which, as usual, has little and in this case nothing to do with the
facts.
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's ****ed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)

Ch4 3D Optical Advice
 

On 22 Nov, 09:42, Kennedy McEwen wrote:
In article , Roger
writes
"Dave W" wrote in message
....
Nobody has achromatic lenses in their eyes, i.e. red and blue need
different focus settings. The eyes of those under 40 adjust
automatically to suit the prevailing conditions, but pensioners like
me have lost the power of accommodation, and need different glasses
for different distances.

I found the right-eye blue image on Channel 4's 3D programmes badly
out of focus using my TV glasses.

So go to the opticians and have *pair of glasses made from a correct
prescription - or a correct eye test. *Avoid Specsavers as they use the
"nearest" that will do to save costs.

Rant missing the point snipped

No one else needs to do this - the problem is YOURS and only YOURS.
God knows why you think that your incorrect lenses in your glasses are
going to affect everyone else. *If you need a new prescription go and get
it.
If you need to rotate a lens it shows you have astigmatism and the current
lenses are no good. *If one eye and lens provides an image out of focus
compared to the other eye it means your sight has deteriorated since your
prescription or that your prescription does not match the lens.

No optician will prescribe lenses which fix the problem that the OP, and
myself, have and it ISN'T astigmatism. *Try reading the first sentence
of his post again and it might help you understand the problem. *The OP
may well be able to get very good, or at least acceptable, polychromatic
vision correction. *However, when filtered to specific colours, the
correction is off. *"Correct" glasses aren't going to fix this - as the
OP says, "nobody has achromatic lenses in their eyes" - and no optician
provides achromatic corrective lenses either!
--


Thank you very much Kennedy for standing up for me against Roger,
saving me the bother of doing it! I was just suggesting things to try
for those who had dismissed the 3D programmes as rubbish (like Roger).
As a matter of fact I find these amber/dark-blue ones are no worse
than the previous red/light-blue C4 programmes, after I did my thing
with the glasses. I wonder if it might be a better system if the amber
was on the normally dominant right eye for best colour impression,
leaving the left blue eye to give the 3D.

I was also interested in your account of the coloured dashboard
displays. This is certainly another thing to be considered when buying
a new car.

Re the discussion about future methods of 3D on TV, now that we have
digital broadcasts and LCD or plasma screens, everything is in place
for exact picture positioning. Lenticular lenses can be put precisely
above pixel columns, so that each eye sees alternate columns. The left
and right views would light up alternate columns so that each eye sees
its appropriate picture without glasses (but you couldn't move your
head sideways without reversing the 3D effect). I saw an excellent
demo of this at a BBC exhibition.

Alternatively, vertical or horizontal polarising strips could be used
instead of lenses (probably not on LCD though). The viewer would have
to use polarising glasses but would have unconstrained sideways
movement.

Dave W