Searching a fast LCD shutter

[Tilmann Reh]

(Xpost + Fup2 s.e.c)

Hello, I am looking for a fast optical shutter (probably LCD).
It must switch between (almost) transparent and black at a frequency of
about 100 Hz, with switching times of about 1 ms. The needed area is
only about 1x1 cm, but the device may also be somewhat larger.

I am aware of "3D glasses" that contain two LCD shutters, maybe this is
the right technology. However, I don't know any company that produces
(and delivers) such shutters as bare LCDs...

Any hints/ideas?

Thanks,

 

[Mike Harrison]

(Xpost + Fup2 s.e.c)

Hello, I am looking for a fast optical shutter (probably LCD).
It must switch between (almost) transparent and black at a frequency of
about 100 Hz, with switching times of about 1 ms. The needed area is
only about 1x1 cm, but the device may also be somewhat larger.

I am aware of "3D glasses" that contain two LCD shutters, maybe this is
the right technology. However, I don't know any company that produces
(and delivers) such shutters as bare LCDs...

Any hints/ideas?

Thanks,

May be worth posting to sci.optics - I'm sure this sort of thing is available for lab optical uses,
but won't be cheap.
Also do a search on Kerr and pockels cells

 

[Roger Hamlett]

(Xpost + Fup2 s.e.c)

Hello, I am looking for a fast optical shutter (probably LCD).
It must switch between (almost) transparent and black at a frequency of
about 100 Hz, with switching times of about 1 ms. The needed area is
only about 1x1 cm, but the device may also be somewhat larger.

I am aware of "3D glasses" that contain two LCD shutters, maybe this is
the right technology. However, I don't know any company that produces
(and delivers) such shutters as bare LCDs...

Any hints/ideas?

Thanks,

Such shutters are very common, but most do not produce the contrast range
you are hoping for (the commonest designs require one layer to be a
polariser, giving about 50% attenuation when 'open'. There are some newer
designs though. Look at (for an example):
http://www.bnonlinear.com/Shutter/Intro/LFSeries.html
These require higher voltages to drive, and should just about meet your
requirements.
The same company also does polariser based units, that are much faster.

Best Wishes

 

[John Fields]

(Xpost + Fup2 s.e.c)

Hello, I am looking for a fast optical shutter (probably LCD).
It must switch between (almost) transparent and black at a frequency of
about 100 Hz, with switching times of about 1 ms. The needed area is
only about 1x1 cm, but the device may also be somewhat larger.

I am aware of "3D glasses" that contain two LCD shutters, maybe this is
the right technology. However, I don't know any company that produces
(and delivers) such shutters as bare LCDs...

Any hints/ideas?

 

[Boris Mohar]

(Xpost + Fup2 s.e.c)

Hello, I am looking for a fast optical shutter (probably LCD).
It must switch between (almost) transparent and black at a frequency of
about 100 Hz, with switching times of about 1 ms. The needed area is
only about 1x1 cm, but the device may also be somewhat larger.

I am aware of "3D glasses" that contain two LCD shutters, maybe this is
the right technology. However, I don't know any company that produces
(and delivers) such shutters as bare LCDs...

Any hints/ideas?

Thanks,

Auto darkening welding helmets.



Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca

 

[[email protected]]

(Xpost + Fup2 s.e.c)

Hello, I am looking for a fast optical shutter (probably LCD).
It must switch between (almost) transparent and black at a frequency of
about 100 Hz, with switching times of about 1 ms. The needed area is
only about 1x1 cm, but the device may also be somewhat larger.

I am aware of "3D glasses" that contain two LCD shutters, maybe this is
the right technology. However, I don't know any company that produces
(and delivers) such shutters as bare LCDs...

Any hints/ideas?

Thanks,

You might try the LCD screen from some shutter glasses. I have a pair
I built the controller for. About 20 volts of about 1 KHz square wave
blackens the LCD. The squarewave itself is turned on and off at about
60 Hz from the CRTs video sync, so the LCD will switch that fast.

 

[Tilmann Reh]

May be worth posting to sci.optics - I'm sure this sort of thing is
available for lab optical uses, but won't be cheap.

I will post there as a second try - but maybe I'm already on the right
way with the 3D glasses technology...

Also do a search on Kerr and pockels cells

Far too high voltage drive requirements, I think.
Thanks anyway.

 

[Tilmann Reh]

Such shutters are very common, but most do not produce the contrast range
you are hoping for (the commonest designs require one layer to be a
polariser, giving about 50% attenuation when 'open'.

That might eventually be a problem. I will have to check that...

There are some newer
designs though. Look at (for an example):
http://www.bnonlinear.com/Shutter/Intro/LFSeries.html
These require higher voltages to drive, and should just about meet your
requirements.

Thanks for the link, these are really interesting devices.
However, from the datasheet they open fast (1-3 ms) but close rather
slowly (10-20 ms), and the working frequency is specified at max. 30 Hz.

The same company also does polariser based units, that are much faster.

Thanks, I will also look at those.

 

[Tilmann Reh]

Google is your friend.

Not always. In this case it is not trivial to find the right links out
of the 839.000 hits...

In such cases the experience and practical help of colleagues is
welcome. I think that's exactly what Usenet is for.

 

[Tilmann Reh]

You might try the LCD screen from some shutter glasses.

That was exactly my first guess.

I have a pair
I built the controller for. About 20 volts of about 1 KHz square wave
blackens the LCD. The squarewave itself is turned on and off at about
60 Hz from the CRTs video sync, so the LCD will switch that fast.

That sounds good. Do you have more detailed information about the maker,
especially that of the screens themselves?

 

[Tilmann Reh]

Auto darkening welding helmets.

I also thought in that direction, and was pointed to ferroelectric LCD
technology that is used for these. Much faster than "normal" LCDs, but
their transparency is only about 25% in the "open" state.

I will have to check if there also are more transparent devices using
this technology. Do you know concrete makers of the pure LCDs?