Google 'LCD shutter'. I'd be experimenting with a cheap commerical device for < $3. This is normally an application for welding goggles or protecting against the flash (or trying to!) when a nuclear weapon ia exploded. The normal twisted nematic device with typically a few to tens of milliseconds switching is too slow for this and other effects such as electrochromic displays have been explored. In terms of making a chiral smectic C* (the standard form for such a device) normally devices are spaced thicker than TN devices and hold the orientation of the LC after switching and need a 0V signal to return to the opposite state. remember if polarizers are used in any device they're not 100% effective in the crossed position and a completely efficient single polarizer would block 50% of the light. Remember too that LC's require AC fields to switch between ITO electrodes. Are you building your own device? Needs a clean room and a fair bit of investment to do this well and more than a one-off. You'd probably get Far East manufacturers to offer an engineering service here against a specification. What switching speed do you require? Do you require a bistable device? What's the application?

Hey Alan,

First off thank you very much for the quick response.

I am working currently in a lab that handles liquid crystals.

I am working on my spare time on creating a device that will involve smectic or chiral liquid crystal.

The goal of the project is to create a mixture of chiral \ smectic liquid crystal with a transparent UV glue, sandwiched between to ITO glasses. I will than polymerize the UV glue. In my end result in want to try to create a device that when switched off reflects most of the visible light, and when switched on is transparent.

For this device I can chose to go both ways, either to use Smectic liquid crystal, or to us chiral liquid crystal with polarizers.

The switching time is less important.

I have the UV equipment and the AC supply.

If you need any more information I just ask and I replay shortly.

Thank you very much for the help.

Buy a shutter device then if switching time isn’t important. However, you will find entertainment in building your own device. A disclaimer - I worked in the LCD industry for 7 years.... Main piece of advice - cleanliness is everything. I assume you can work in Class 100 conditions at home? And you can space your 2 pieces of glass in the region of 5 - 25 microns with a tolerance of 0.1 microns or better. And that you can fill your devices under vacuum - or will you splat seal before polymerizing the UV adhesive?

I can space my 2 pieces together with a 5-25 um. Cleanliness is not a problem. I cant fill it under vacuum. What I might do is use ITO coated PET, and put the mixture in between them and use a coater. that way I wont need vacuum between my glasses. the coating will take out the air. but the main problem is the materials to us. which kind of chiral liquid crystal should i use to block the 400-700 nm light spectrum.

The LC doesn’t block the spectrum - it’s the change in orientation of the LC structure that does. Chiral smectic C is the most studied system here. You could also consider a dyed-nematic effect with 3pi/2 structure (super twist) to reduce the switching time. What size of device are you considering? How will you space internally (within the LC structure)?

Thank you again for the answer.

I understand that the change in orientation of the LC structure blocks the spectrum. I space the device eventually with spacers that are per-mixed in the mixture.

Do you have a Chiral smectic C liquid crystal to recommend me? An LC that I could work in room temperture?

See:

https://booksite.elsevier.com/9780125137454/pdf/nal0701.pdf

and contact your local Merck liquid crystal distributor

Thank you very much for the book and the information.

Do you have any recommendations ? there are many different chiral \ smectic liquid crystals out there.