No, the fact that the chips don't move at ALL means they need NO alignment.
"In any case nothing stays perfectly aligned."
Like I tried to relate to you before... the chips on you computer's motherboard don't un-align do they????
The 3 display chips I'm talking about whether LCD, DLP, GLV, or LCoS are all just computer chips that have their leads soldered to a one piece board/housing. No chip can move out of alligment from the others.
How would you know? Are you sure? Would you notice if the CPU on your motherboard shifted 0.001 mm or raised one corner a few fractions of seconds of arc? I bet the chips on a typical circuit board do shift in relation to each other across a 60 degree F range enough to be optically detected. More to the point, I bet they shift a lot more in relation to the case, or maybe the hard drive.
Whether they shift an amount that is significant I couldn't say, but to say absolutely something is perfectly aligned (hint - not possible) and never moves is silly.
They're ALL 3 chip systems, and ALL only have one output lens (which can't get un-aligned except with the screen (which can happen to ANY projector design), or out of focus (which, again.. can happen to ANY projector design), but even those can hardly happen if nothing touches the projector.
From the illustration on the DLP site I can see at least (1) variations in manufacturing the housing that holds the prizm and (2) variations in the prizm and (3) possible thermal shifts due to the housing expanding and contracting that could (actually will) happen. Now I've not examined an accurate drawing or done any math to see whether it's likely to be 0.1 pixel or 0.0000001 pixel error in the worst case, but error will be present due to unavoidable variations in manufactured parts.
CRT's don't shift with age. They shift from movement and heating/cooling cycles, and it's a very very tiny amount.
I tweak my CRT's guns about every month or so. It just takes a few minutes. Do it during a commercial and you'll never call it an 'issue'.
This comment was intended with regard to the paragraph immediately preceeding it regarding color rendition. CRT phosphor fades (I'm told) as they age.
From an older post:
I forgot to mention some other cool things about the GLV system....The micro ribbons of the chip don't have to be either 'on or off' like DLP has to do.
They can 'partically deflect light' to create grayscale whereas DLP has to turn on/off super fast to do this. Not that the DLP chip doesn't do a good job on grayscale, just that it physically works WAY harder to do it.
Actually the on/off nature of DLP is one of its' strongest good points to my mind, as accurate linear control of duration is simple compared to analog control of intesity.
[This message has been edited by charlie (edited November 22, 2002).]
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