Ch4 3D Optical Advice
 

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. I was able to solve the problem by
swinging my glasses off my right eye so that it saw the screen
directly through the blue filter. Both eyes saw a focussed image and
the 3D experience became a pleasure not a pain.

Those oldies who need glasses for everything would not be able to do
this - all they could do is use their distance glasses on their right
eye and their TV glasses on their left, probably looking through them
from front to back to keep the ear hooks out of their face.

Varifocal users might be able to rotate their glasses clockwise a bit
so that the right eye sees a weaker part of the lens.

Dave W

Ch4 3D Optical Advice
 

On Sat, 21 Nov 2009 02:51:43 -0800 (PST), Dave W
wrote:

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. I was able to solve the problem by
swinging my glasses off my right eye so that it saw the screen
directly through the blue filter. Both eyes saw a focussed image and
the 3D experience became a pleasure not a pain.

Those oldies who need glasses for everything would not be able to do
this - all they could do is use their distance glasses on their right
eye and their TV glasses on their left, probably looking through them
from front to back to keep the ear hooks out of their face.

Varifocal users might be able to rotate their glasses clockwise a bit
so that the right eye sees a weaker part of the lens.

Dave W

I think you are maybe looking for perfection here!!!

How about investigating prescription tinted glasses with one lens
tinted red and the other tinted blue? You would need to have your
eyes tested separately under coloured lights. This would maken an
interesting challenge for your optician.

Any opticians out there that could comment on this?

Ch4 3D Optical Advice
 

In article , Scott
wrote:
How about investigating prescription tinted glasses with one lens
tinted red and the other tinted blue? You would need to have your
eyes tested separately under coloured lights. This would maken an
interesting challenge for your optician.

Don't waste your money. (And in any case it's amber and blue). This
system is not going to catch on - the results are far too flawed and
eyestrain making. Its attempts to represent colour mean that there are
more problems than even the red/green system (which only works on
monochrome originals) and that's problematic enough. I got considerable
ghosting caused by breakthrough of the other eye's image, a strange
ripping on the blue eye on panned shots, very dodgy colour effects and
a headache.

Several firms are working on 'proper' 3-D TV (presumably all
incompatible as usual) so I should wait for the dust to settle.

Ch4 3D Optical Advice
 

Why are they using the 2 colour glasses, these failed in the cinema years
and years ago.
Going to see Disney's A Christmas Carol tonight in 3D Imax I doubt they will
use red/ green or blue glasses.
When I went to see Dolby Digital and a Real 3D films the glasses were not
the above coloured ones.

--
Regards,
David

FREESAT HD as it is now it is a joke.

Ch4 3D Optical Advice
 

On Sat, 21 Nov 2009 17:52:48 -0000, "David"
wrote:

Why are they using the 2 colour glasses, these failed in the cinema years
and years ago.

Possibly because the 2 colour method is the only one that can be used
with standard TVs.

Going to see Disney's A Christmas Carol tonight in 3D Imax I doubt they will
use red/ green or blue glasses.
When I went to see Dolby Digital and a Real 3D films the glasses were not
the above coloured ones.

Were they polarised?

--
Peter Duncanson
(in uk.tech.digital-tv)

Ch4 3D Optical Advice
 

David schrieb:
Why are they using the 2 colour glasses, these failed in the cinema
years and years ago.
Going to see Disney's A Christmas Carol tonight in 3D Imax I doubt they
will use red/ green or blue glasses.
When I went to see Dolby Digital and a Real 3D films the glasses were
not the above coloured ones.


Please try to think about it first - normal TV sets are not able to
separate left and right vision frames electronically. Only colour
separation (red/blue or amber/blue like in this case) can provide for
cheap "glasses" and many spectators (private TV needs viewers for ads).

There is 3D-TV with HDTV quality and LCD-shutter glasses like in digital
3D cinemas - but it´s not cheap enough for the avarage viewer...

Klaus

Ch4 3D Optical Advice
 

"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.

I was able to solve the problem by
swinging my glasses off my right eye so that it saw the screen
directly through the blue filter. Both eyes saw a focussed image and
the 3D experience became a pleasure not a pain.


It was a load of rubbish the whole 3D thing, it was NOT correct 3d
so very few people saw the effects that were possible in tests on TV
in the 80's. What you saw was a remastered original of poor quality
with various colour filters and images pieced back together. It was a
complete waste of time as there was no real 3D images.


Those oldies who need glasses for everything would not be able to do
this - all they could do is use their distance glasses on their right
eye and their TV glasses on their left, probably looking through them
from front to back to keep the ear hooks out of their face.


You seem to forget that not everyone is wearing glasses that are not
effective or match their current needs! Jut because your glasses are
not suitable it doesn't mean everyone else is the same. The problem is
individual to YOU and YOU alone.

Varifocal users might be able to rotate their glasses clockwise a bit
so that the right eye sees a weaker part of the lens.


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.

Dave W

Ch4 3D Optical Advice
 

"David" wrote in message
...
Why are they using the 2 colour glasses, these failed in the cinema years
and years ago.
Going to see Disney's A Christmas Carol tonight in 3D Imax I doubt they
will use red/ green or blue glasses.
When I went to see Dolby Digital and a Real 3D films the glasses were not
the above coloured ones.

--
Regards,
David



I still have my 3D glasses from the mid 80's when CH4 tried a few 3D films.
They were red and blue, not red and green as the glasses are now. With the
red and blue the picture looked perfect and 3D worked quite well with things
poking out of the screen etc. What was on the other night was a complete
joke, it wasn't 3D, it was old films manipulated and put togther using
different
coloured filters - it didn't work as they did it incorrectly.
It was a total flop due to a misunderstanding of those responsible about 3D.

Ch4 3D Optical Advice
 

"Roger" wrote in message
...

I still have my 3D glasses from the mid 80's when CH4 tried a few 3D
films.
They were red and blue, not red and green as the glasses are now.

What do you mean *now*?

With the
red and blue the picture looked perfect and 3D worked quite well with
things
poking out of the screen etc.

....but very washed out colour.

What was on the other night was a complete
joke, it wasn't 3D, it was old films manipulated and put togther using
different
coloured filters - it didn't work as they did it incorrectly.
It was a total flop due to a misunderstanding of those responsible about
3D.

Did you watch the recent C4 3-D with *blue/amber* (ColorCode) glasses as you
should have done?

(I agree it wasn't very good, but you've got to get the colours right for it
to work at all.)

--
Max Demian

Ch4 3D Optical Advice
 

Went to see Disney's A Christmas Carol last night at the proper Imax cinema,
giant floor to ceiling square's screen from 2 70mm films running
horizontally, in 3D, it was fantastic as they say in the adverts for proper
Imax... Crystal Clear and high powered sound.
They did not use the whole height of the screen but used the width so it was
the usual widescreen cinema format.
I can recommend you to go see this in today's 3D.
I may well go to see it in Digital Real 3D at the multiplex to compare.
Because of the effects in this film I would think the normal film
presentation would be a let down. The local multi-plex has the film on in
one screen as 3D and in another as 2D, they charge £2 extra for the 3D
usually, I assume for use of glasses or just to take more money as you only
get the loan of the glasses.

--
Regards,
David

FREESAT HD as it is now it is a joke.

Ch4 3D Optical Advice
 

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!
--
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
,
Dave W writes
Nobody has achromatic lenses in their eyes, i.e. red and blue need
different focus settings.

Tell me about it. I started needing corrective glasses for reading a
few years ago, although my distance vision is still better than 20/20
which, contrary to popular opinion, is merely an acceptable standard and
not perfect vision.

However, when I rented a VW Passat a while back I noticed that I could
not read any of the red LED indicators on the dashboard at night without
my reading glasses, but while I couldn't read the blue LED indicators
*with* my reading glasses I could read them perfectly well without
glasses. In other words, I could focus closer with blue than with red
when it was relatively dark and my irises were wide open.

That led me to investigate further. The difference isn't so much in
daylight, in fact it is very difficult to detect at all. However once
the light levels drop so that my irises are open wide then it becomes
much more noticeable. Red focuses well at distance but require +2.5
diopter correction at arms length and more closer. Blue is the opposite
and focus well at arms length yet require -1 dioptre correction at
distance. Green seems to be ok at distance but requires about +1
diopter at arms length.


--
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
 

"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. I was able to solve the problem by
swinging my glasses off my right eye so that it saw the screen
directly through the blue filter. Both eyes saw a focussed image and
the 3D experience became a pleasure not a pain.

Those oldies who need glasses for everything would not be able to do
this - all they could do is use their distance glasses on their right
eye and their TV glasses on their left, probably looking through them
from front to back to keep the ear hooks out of their face.

Varifocal users might be able to rotate their glasses clockwise a bit
so that the right eye sees a weaker part of the lens.

Dave W



I was really looking forward to "Friday the 13th Part III (3D)" having so
much enjoyed Jaws III 3D and the the 3D adventures of the early 1980s when
everything worked perfectly.

Sadly, this week's Channel 4 3D week has been a failure for me and I've had
to abandon Friday the 13th after about 20 minutes.

I see a double image in most, but not all frames, and what I see has very
little 3D effect.

I believe the problem may be poor quality or sub-spec glasses. The blue lens
seems cloudy and obfuse to me compared to the clearer yellow lens.

I've tried adjusting it and cleaning it with no joy.

It's a relief to take the glasses off and get back to high quality (tongue
in cheek) digital terrestrial TV. *



* The over-compressed pixilated picture quality of yesterday's rugby match,
apart from the benefit of widescreen, was worse, nay far worse, than the TV
picture I used to have in the early 1980s using an indoor aerial. Pointless,
digital TV really is pointless.

Ch4 3D Optical Advice
 

On 22 Nov, 23:19, "Light of Aria"
wrote:
"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. I was able to solve the problem by
swinging my glasses off my right eye so that it saw the screen
directly through the blue filter. Both eyes saw a focussed image and
the 3D experience became a pleasure not a pain.

Those oldies who need glasses for everything would not be able to do
this - all they could do is use their distance glasses on their right
eye and their TV glasses on their left, probably looking through them
from front to back to keep the ear hooks out of their face.

Varifocal users might be able to rotate their glasses clockwise a bit
so that the right eye sees a weaker part of the lens.

Dave W

I was really looking forward to "Friday the 13th Part III (3D)" having so
much enjoyed Jaws III 3D and the the 3D adventures of the early 1980s when
everything worked perfectly.

Sadly, this week's Channel 4 3D week has been a failure for me and I've had
to abandon Friday the 13th after about 20 minutes.

I see a double image in most, but not all frames, and what I see has very
little 3D effect.

I believe the problem may be poor quality or sub-spec glasses. The blue lens
seems cloudy and obfuse to me compared to the clearer yellow lens.

I've tried adjusting it and cleaning it with no joy.

It's a relief to take the glasses off and get back to high quality (tongue
in cheek) digital terrestrial TV. *

* The over-compressed pixilated picture quality of yesterday's rugby match,
apart from the benefit of widescreen, was worse, nay far worse, than the TV
picture I used to have in the early 1980s using an indoor aerial. Pointless,
digital TV really is pointless.

Is the Digital Switchover ********? :)

Ch4 3D Optical Advice
 

Light of Aria wrote:


"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. I was able to solve the problem by
swinging my glasses off my right eye so that it saw the screen
directly through the blue filter. Both eyes saw a focussed image and
the 3D experience became a pleasure not a pain.

Those oldies who need glasses for everything would not be able to do
this - all they could do is use their distance glasses on their
right eye and their TV glasses on their left, probably looking
through them from front to back to keep the ear hooks out of their
face.

Varifocal users might be able to rotate their glasses clockwise a
bit so that the right eye sees a weaker part of the lens.

Dave W



I was really looking forward to "Friday the 13th Part III (3D)"
having so much enjoyed Jaws III 3D and the the 3D adventures of the
early 1980s when everything worked perfectly.

Sadly, this week's Channel 4 3D week has been a failure for me and
I've had to abandon Friday the 13th after about 20 minutes.

I see a double image in most, but not all frames, and what I see has
very little 3D effect.



Friday 13th Part 3 was a dire conversion. Firstly they had to deal with
a horrendously grainy print. It was awful. Secondly the conversion
from Polarised 3D to the ColorCode3D that channel 4 used was awful.
Conversion from the Red/Blue 3D of old would be more suited but Friday
13th was not filmed that way. The double image syndrome was more
visible during the darker scenes and as there was a lot of dark scenes
it seemed more noticable overall.

I too gave up after 20 minutes because to get any kind of decent 3D
effect you had to be almost on top of the TV but the print was so bad
it was unwatchable so close up (and I was watching on CH4 HD).


I believe the problem may be poor quality or sub-spec glasses. The
blue lens seems cloudy and obfuse to me compared to the clearer
yellow lens.


Me too. However, I think the quality of the conversion matters. It
was worse when programs were converted from other 3D formats but was
acceptable on original ColorCode formated programs like the Derren
Brown thing.


MC

Ch4 3D Optical Advice
 

Modern 3D TV when launched is likely to use circularly polarised
specs.

UKM

Ch4 3D Optical Advice
 

"UKMonitor" wrote in message
...
Modern 3D TV when launched is likely to use circularly polarised
specs.

I've always wondered about polarised 3D. In a cinema you can have two
projectors aimed at the screen, using polarising filters at 90 degrees to
each other. But how do you make a TV screen produced polarised light that
the polarised specs can separate into different left and right images?

Ch4 3D Optical Advice
 

"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?

2 TV sets, now there is a thought.
LOL

Regards
David

Ch4 3D Optical Advice
 

Martin wrote:

"UKMonitor" wrote in message

...
Modern 3D TV when launched is likely to use circularly polarised
specs.

I've always wondered about polarised 3D. In a cinema you can have two
projectors aimed at the screen, using polarising filters at 90
degrees to each other. But how do you make a TV screen produced
polarised light that the polarised specs can separate into different
left and right images?

Interlaced?

MC

Ch4 3D Optical Advice
 

Me too. However, I think the quality of the conversion matters. It
was worse when programs were converted from other 3D formats but was
acceptable on original ColorCode formated programs like the Derren
Brown thing.


MC


Thanks MC. I am glad it wasn't just me experiencing this. It was a joy to
get back to 2D 16:9 after this!

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