(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
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):
Best Wishes
Auto darkening welding helmets.
Regards,
Boris Mohar
Got Knock? - see: Viatrack Printed Circuit Designs (among other things)
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.Mike Harrison schrieb:
I will post there as a second try - but maybe I'm already on the right way with the 3D glasses technology...
Far too high voltage drive requirements, I think. Thanks anyway.
Roger Hamlett schrieb:
That might eventually be a problem. I will have to check that...
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.
Thanks, I will also look at those.
John Fields schrieb:
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.
snipped-for-privacy@hotmail.com schrieb:
That was exactly my first guess.
That sounds good. Do you have more detailed information about the maker, especially that of the screens themselves?
Boris Mohar schrieb:
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?
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