Matte Coating for IR Plastic?

[brianl6403]

I am looking for a coating that can be applied to IR plastic that takes away the "gloss" of the material, yet does not impact the clarity of the substrate.

Any assistance is appreciated.

Thanks.

 

[btrueblood]

What exactly is your "IR Plastic" in terms of a polymer? Polycarbonate?

I've seen matte IR cover lenses, and they appear to have a molded-in texture, not a coating.

 

[patprimmer]

Taking away the gloss by it's nature will change the characteristic from transparent to translucent. Are you sure of your terminology. And Btrue is correct re the IR We can only guess you mean IR transparent plastic of some type, or do you mean IR opaque but transparent to visible light. Your question is far from CLEAR, at least to me.

Regards
Pat
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[Demon3]

Gloss depends upon surface roughness so you can make the surface matte using a textured mold when you make the part. Any roughness of the right dimensions to scatter visible lights is likely to affect IR as well because the wavelengths are similar.

If the feature sizes were controlled very carefully then, in theory one could preferetially scatter mainly the visible light. However, I think developing that surface would be a multiyear project.

Chris DeArmitt

"Knowledge has no value except that which can be gained from its application toward some worthwhile end."
Think and Grow Rich - Napoleon Hill

 

[brianl6403]

I apologize for the lack of clarity (pun intended) in my question, as I'm not a polymer, IR, or optics expert, by any means - but I came to this site to hopefully find a creative solution from the experts...

Patprimmer, yes, I understand the difference between transparent and translucent. Let's assume, for this debate, that the plastic is polycarbonate, and that it needs to also remain IR transparent, optically clear (for camera use), but opaque to visible light. ie. I don't want anyone to see through it. I do understand that having a texture on the surface removes the gloss, yet, whether it's integrally molded, or applied, is what ruins the optical clarity. This is not acceptable. I'm looking for a film, coating, polymer, or other that would allow IR transparency, optically clear, yet opaque to the naked eye, without the high gloss on IR materials I've seen to date.

Does anyone have experience with IR inks? What would happen if I mixed IR inks into matte polymers, like a urethane resin?

Are there other IR materials that I might experiment with?

Or maybe it's a combination of polarizing filters that, when combined they achieve these results?

Or maybe something else? I'm open to anything, please be creative. This is not an effort of science, it's more for art, so I'm not concerned about "following rules", so to speak, and am not concerned about cost (yet).

Thanks again, I appreciate the dialogue.

 

[patprimmer]

Leave the surface glossy if you want true transparency.

You need a polymer that is IR transparent. PC is.

You need to colour it, either by incorporating pigments into the resin before moulding or by coating. Before moulding is best as it cannot scratch off.

There are pigments that transmit IR but not visable. Suppliers of pigments or colour masterbatches should be able to provide detailed info.

Regards
Pat
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[brianl6403]

Patprimmer,

You've nailed my problem: I want true transparency, but I can't have the gloss.

 

[IRstuff]

Then you can't have imaging either. The gloss is a byproduct of having a smooth surface, which is needed to get any degree of image quality.

Your only recourse is as Pat suggests, dyeing the window material with something that passes IR, but blocks visible, as is found in most TV remotes.

TTFN

FAQ731-376

 

[brianl6403]

IRstuff,

Dang! Can't I have it all??

So, if I were to use a dye, could I do it in a way that didn't produce a glossy surface?

 

[btrueblood]

What is your objection to a glossy (shiny/smooth/reflective surface) lens that is opaque to visible light, yet transparent to IR?

 

[patprimmer]

You can wish upon a star, but it still won't happen.

Regards
Pat
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[brianl6403]

btrueblood,

I don't want to call attention to it. It's an aesthetic issue, not a scientific one.

 

[IRstuff]

So, do the opposite:

http://en.wikipedia.org/wiki/Purloined_Letter,

make everything glossy

TTFN

FAQ731-376

 

[btrueblood]

Who are you spying on?

You can bury the lens in a hole to reduce incident light, or put it behind a grille or screen (both will degrade the image quality).

 

[Demon3]

Some guy with IR binoculars that doesn't want any reflections coming off the lens.

Chris DeArmitt

"Knowledge has no value except that which can be gained from its application toward some worthwhile end."
Think and Grow Rich - Napoleon Hill

 

[IRstuff]

You can minimize reflections with absorbing materials, but you cannot make it matte.

TTFN

FAQ731-376