LOC RED SLED - The Other Diode Information

I removed the other diode from the LOC sled. This diode is the one in the hexagon shaped heat sink. It has a lens, and a "sandwitch" of two pieces of glass with a film in between the glass. I operated it at about 90ma and projected the expanded image on the wall. I viewed it with my infrared viewer "find-r-scope" The "spot" had thousands of vertical lines equally spaced very precisely. The dark lines appeared to be about 1/2 the width of the "light" sections. It was a very cool looking pattern.

Does anyone know what this thing does?