What material blocks IR, but passes visible light?

[trains are bad]

I built a visible light meter using a light-to-frequency IC and it totally works, but it's too IR sensitive. I knew the absorption spectrum of the silicon sensor was biased toward IR but I figured it might work anyway since lots cameras use Si sensors, plus I hoped that my glass lens in my meter would absorb some IR and of course it will be OOF on the measurement plane compared to visible light. However grass makes the sensor respond much more than a sheet of white paper even though the paper is much whiter. So clearly I have terminal IR problems at this point.

The only solution I can think of is to get some kind of filter that will filter out IR and pass visible light, but I don't know what material to use. Most common "IR filters" are designed to pass IR and block visible, such as for remote controls and stuff.

I know that some projectors take the light from the lamp and bounce it off a special mirror that lets the IR pass and reflects the visible light, but I don't know what's special about the mirror. How do cameras that use silicon photosensors get around this problem?

[Spider-TW]

Idk where you would get a scrap, but there are those car and house window films that are mostly clear, but block IR.

[vf-xx]

Talk to a high end car tint shop. They should be able to get you a scrap.

I know that when I was looking to tint my car they offered films that didn't darken the window noticably, but were designed to reflect IR and UV.

[Warwitch]

Idk where you would get a scrap, but there are those car and house window films that are mostly clear, but block IR.


Ive never seen IR window coatings, only UV??

Only way to filter out the IR wavelengths (and only those) would require a bandpass coating of some kind.

[vf-xx]

just a quick Google (http://www.anapro.com/english/product/ir-blocking-film.asp)

[FinchMan]

you might find an old digital camera or webcam and steal its IR filter.