IR to visible converter

I have in my hands a little credit card sized piece of plastic which has a little square of a substance painted in the centre. You charge up the substance in daylight for a few seconds and then it emits light in the visible spectrum when expose to an IR source like a TV remote control.

As the remote control is activated the substance flashes.

I think it may be some kind of fluorescent powder/ink but the ones I have found are hugely expensive.

What do you folks think is being use as the IR/Visiblr converter?

TIA

Streak

The susbstance on the credit card sized detector is basically Calcium Sulphide or Strontium Sulphide doped with Europium, Samarium, Ytterbium, or Erbium, typically in metal pairs. Apparently this is always done with rare earth pairs! The Sulphide's are simple enough, they phosphoresce in nature, but what do the dopant metals have to do with IR you may wonder? You DO have to "light-pump" this stuff with higher energy photons before you can make the IR trigger the emission of visible photons thus the IR merely triggers the release of the stored "visible light" photons. As for price, I have the one that they sell at Radio Shaft, and it wasn't terribly expensive, but then again that was over five yrs ago.

Regards,

Abbie

Thanks Abbie. Great answer.
I was thinking of trying to get hold of the material/compound that is being used to try and make some of my own detectors.
Do you think there is a company who can supply the compound or would I have to formulate my own?

Streak

does Radio 'Shaft' still sell this?

I have one with an active area of about 3" by 2" and it's double-sided so you can view it from the back. This is helpful for inspecting fiber optic connectors for the presence of IR.

IUt was really expensive back in the early 90s (over a hundred bucks for the wavelength sensitivity that I needed) but I've seen the larger ones now for around $35.

There's also a new formulation that does not require pre-charging and thus doesn't 'fatigue' when being used to view IR.

AbnerCadaver,

I've never noticed you posting on CPF before. Welcome!!! I appreciate good technical explanations! Thank you!

Larry