I maintain the web site you linked in your post. I assume the lens in question came from the "middle-left" portion of the optical block as pictured below (from a photo originally posted by "tdma" a few posts up):
When you say it is the "third lens," could you provide a list of the lenses that occur prior to the first mirror in the upper-left? Doesn't the first lens look very similar to the one you posted about (a "series of parallelograms")?
You don't explicitly state it, but can I assume that you just ended up removing the lens, because it appeared it scorched, and you were unable to clean it without breaking it?
My concern would be that it is a filter that removes IR and/or UV light. Unfiltered IR and UV light are known to accelerate degradation of the more sensitive filters and LCD panels downstream. So, while things may look brighter in the short-term, you might be damaging other parts.
Alternatively, it may be an "integrator" (creates the rectangular area of light necessary for the TV, a "relay lens," a "collimator lens" (makes all of the light waves parallel to each other so that the LCD panel will scatter them properly), or something else. If anybody knows, please speak up. Here is a schematic from a Sony patent that I posted previously:
I think this diagram is for the A10/ A2000 models.
You are on the right path with this. (pun intended). This light path is now very intense and will damage the mirrors, magnifiers and LCD panels in a very short period of time. It may even shatter the first reflector because the light will convert to heat when changed thats why that part gets cooked. I suggest putting the optical block back together with the proper parts before it gets damaged beyond a reasonable repair. A new one will cost over $500.00
Steve, not sure if you received my email. I will rebuild your optical block whenever you are ready. Let me know.<<