Originally Posted by Tom Frank
Another user is also pursuing this approach.
FWIW, I have located a lens with glass, asperical lenses that has a 7mm thread which, I think, should screw right into the existing lens mount. It appears to have the same AOV of the stock lens, but has no IR filter on the rear surface like the stock lens. Downside is it costs about the same as the acmera, and still would need to have an appropriate IR filter added.
If I remember correctly, the IR filter on this cameras is a small square or disc of film/glass on the rear of the lens, it's not part of the lens itself. Or at least that's how I remember the one I opened up (I was checking if there was water inside after a splasdown
In any case it's possible to get IR blocking filters, the easiest way would be to use one meant for SLR camera lenses, cutting it to size.