70" XBR2 Screen issue: light Oval Shape around Dark Rectangle

I saw on owen's posts about dismantling his 70" (to paint the interior) that the lens is masked horizontally with some thick black tape, presumably to reduce light leakage a little. It's not masked vertically.


I'm looking at your image and seeing that the top and bottom edges of the dark area are nice and sharp and straight. The left and right edges are fuzzy and *could* be a little convex, hard to tell.


Of course, then the question is: Why would it be *darker* inside of your shape that mimics the masked opening on the lens? I don't know. It's just a correlation, not a conclusion.


Perhaps it's some sort of secondary reflection inside the lens? The top edge of the rectangle may actually be an artifact caused by the bottom mask, for instance. The lighter area above the rectangle could actually be light that's bounced around inside the lens to the point that it exits from the bottom, is partially blocked by the tape at the bottom, and strikes your screen at the top. Dang, I should just draw this or something. I'm not explaining it very well. Let's see...


Okay, a very craptacular diagram should be attached. Sorry it's so bad, I only have mspaint available to me at the moment.


Note that extra light could be coming from something other than internal reflections in the lens. It could be leaking around the side of the LCoS panels, or around some other element of the optical block. This is just a general idea of something that could satisfy my theory...

You actually draw a diagram for me and apologize for the quality. I have to chuckle. I appreciate the thought you put into this!


Your theory seems sound to me.


For me, the exact rectangle shape is the interesting part. I assume that the "effect" is actually the oval shape. For the most part, the middle rectangle is the same level of black as areas outside the oval (except for the very top of the screen, which has always been a bit lighter). Since the effect is dimmed by the iris, I have to assume the light output of the OB is the source -- whether its generated inside the OB or reflection from light once it leaves the lens (as you suggest) is unknown.


After the light level gets high enough, I can't see it. So any color field besides 10-15 IRE gray doesn't show it.


I assume you don't see anything like this on your XBR2?

I haven't looked. I'm not sure I want to know if it does it.

I wonder if this isn't caused by the lamp and/or the lamp reflector. The TV has always had a hot spot in the middle:



But when I edit the dark and gray screens together, I can see that the rectangle is visible in the bright middle of the gray screen (the camera turned it a bit blue).



It is visible in all color fields, if I reduce the picture level low enough.


Maybe this has always been present and I simply never noticed it before. Or perhaps as the lamp has aged the effect is more visible (whether it's the lamp or a reflection, different output levels from the lamp could still change the visbility of the effect).

I agree that the panels don't seem to affect the level of the effect. However, the iris does affect it. So does power saving mode. And it's not caused by the lamp or the lamp reflector, clearly.


I also find that the oval shape is visible in any color field, provided I lower the picture setting low enough (around 5). And the oval is always a slightly brighter version of the same color. When I raise the picture level enough, the image light masks the effect. That suggests that all three light paths are equally affected.


I wonder if it might be a weakness in the polarizing filter. Or some light is by-passing it. Un-polarized light would pass through the LCoS panels unblocked.


I'm going to watch the effect and see if it gets worse. I know for sure it was present 6 months ago (I saw part of the oval on a star field but thought it was a part of the image) and maybe longer.


I find it hard to believe that I'm the only user on this forum who has noticed this (or has the problem).