CurtPalme.com Home Theater Forum

[Jeremy112]

ok this isn't about a CRT, its about a lens for a DLP, but I figure since they both have coatings on them they should act somewhat similar...

I have a 50" DLP TV here that I just replaced the bulb in, but the problem is I noticed when I was cleaning out the inside of the screen where the mirror is, that the coating on the lens is cracking (like paint would do on a dirty or oily surface)

Does this affect focus? I ask because the image is clear in most spots except there are some areas where its a little fuzzy

Any ideas?

[garyfritz]

I would not expect it to, unless it's really really severe. The surface of a lens is nowhere near the focal point, so it takes a LOT of stuff there to affect the image. Try sticking your fingers in front of your CRT lenses -- it darkens the image a bit, because you're blocking a lot of light, but generally it doesn't affect the focus much.

Your DLP's lens is much smaller, so a smaller imperfection will be noticeable. But just small cracks on the surface? I wouldn't think that would be visible.

[Jeremy112]

Thats all I wanted to know, I expect that there is some dirt inside the light engine causing this issue then (The TV was outside for a few days when someone threw it away and then a friend took it and gave it to me)

Thats all I wanted to know, Thanks gary!

[Spanky Ham]

You might want to redeposit an AR coating on the lens. According to James (piratepowwow), it isn't that difficult. I mentioned it to Scott and he thought it wasn't that hard to do either.