PDLC film on low voltage (3-6V)?

[ma55imo]

Hello community,
I am working on a device project that requires a stripe of roughly 6cm*2cm to hide something beneath programmatically. A PDLC film could do the job, but I need to find a way to power with a series of coin cells battery, something between 3 and 6V. All the PDLC films I found are running at a much higher voltage.
Do you believe for such a small surface I have a way to power a PDLC film over one or more coin batteries?

thanks for tips.

 

[anorlunda]

I did a quick search on Amazon and found "Black Box Battery Smart Film Starter Kit 4" X 3" Film Switchable Glass Pdlc"

So, I think a little google searching will find what you want.

 

[ma55imo]

I know thanks for your answer, but they are all 3*12V. As I wrote, I wonder if I can get it to work a smaller size 6cm*2cm with much lower voltage, something around 3 to 6V as I need to use coin cell like batteries.

 

[anorlunda]

To get 60VAC from button batteries would require a high frequency switching circuit and a transformer. I'm not sure about the practical limits of that design. Nor am I sure about the power losses which affect battery life.

Does you design allow for the size and weight of a transformer, a circuit board, and potentially "short" lifetime?

 

[ma55imo]

Live time could be ok, size might not.
Thanks for your answer. Appreciated.

 

[berkeman]

I am working on a device project that requires a stripe of roughly 6cm*2cm to hide something beneath programmatically. A PDLC film could do the job, but I need to find a way to power with a series of coin cells battery, something between 3 and 6V. All the PDLC films I found are running at a much higher voltage.

Yeah, coin batteries and medium high voltage don't really go together very well. It can be done, but it's not a good fit, IMO.

Can you say more about what you want to hide? There are other low-power techniques for hiding and revealing stuff that size. Would it be best if the state were latching? That is, once the hide/show state was changed, it requires no more power to maintain the state.

 

[ma55imo]

I have a green stripe, size 6cm*1cm, the device is 5cm*20cm but it's thin, I could get it to 10-12mm. I have a microcontroller 10mm*20mm and I could use any CR2032 or multiple of them. Been looking at Electrochromic Display which would be better as once the state has changed, they don't need any power, they are also super low power, but I guess they have to be manufactured, I can find screens already commercialized.
I could find cheap PDLC screens but I haven't found anything that could run on a small voltage.
Thanks for any tips.

 

[berkeman]

I have a green stripe, size 6cm*1cm, the device is 5cm*20cm but it's thin

So you want the green stripe to turn black? Or white?

Since the stripe is smaller across than your device, can you just use a low-power mechanical means to move it from one side of the device to the other to hide it?

 

[ma55imo]

Yes, I just need to hide the stripes, they could be black or white or any color really.
The mechanical means is a good idea but the device is flexible so not sure I would manage to do it nicely. I think I need more an ECD or PDLC or something similar.

 

[anorlunda]

Instead of hiding what is beneath, can you put the beneath content on a lcd screen? Lcds are low power, low voltage (as in our phones) and some are flexible.

 

[ma55imo]

yes, that is another solution, for the PoC it will work, but it is not sustainable, those screens will get to 15+ usd when you need to scale, it will have a relevant impact on the device cost.

 

[Tom.G]

How about miniature venetian blinds. They could even be colored green on one side and white on the other. The gear drive you normally see in blinds would not be needed. To open/close the blinds, use a lever arm on each blind and pull with a string (Nylon? Kevlar?) with an electromagnet.

Or if you want single-use, instead of an electromagnet, use a spring to preload the blinds appropriately and a release mechanism (electro-thermal?) to release.

(Just throwing ideas at the wall to see if they stick. )

EDIT:
(found with: https://www.google.com/search?&q=flexible+lcd+shutter)
http://www.lc-tec.se/products/fast-optical-shutters/

also try: https://www.google.com/search?&q=flexible+electrophoretic+shutter
end edit:

Cheers,
Tom