Looking for a one cell lcd display (or something else) to use as a light diode

[supak111]

Hi everyone, I need a device that will block light ONLY when voltage is applied to it. I know LCD displays can do this, in fact they have these cheap little keychains now that are solar and blink the screen ON / OFF to show and hide whatever message you have behind the screen. I just need this in a larger version about 7x4 inches.

I tried using switchable "smart glass" tint but that technology is opaque when power OFF and see through when power is ON, I need it to be opposite and not use any power to be visible. Anyone have any ides?

 

[(*steve*)]

Do these devices use any power anyway (other than for switching)? How long would the charge on a capacitor hold these "open" and would this be sufficient for your needs?

 

[supak111]

That keychain LCD uses power for when the screen is dart. If you cover the solar cell screen goes clear, just like what I'm looking for. And judging from the tiny size of the solar panel they use very small amount of power even to be in the DARK state