Projector with the greatest projection angle

[SAZAR]

A bit about optics. I was wondering what is the film (slide, or motion picture) projector with the widest projection angle. What are the current limitations?

 

[Andy Resnick]

The limitation is on the source brightness; as the projection field increases, the lamp must be brighter and brighter, which approaches damage thresholds of the film stock. Possibly the newer direct projection technologies (like the TI micro-mirror based technology) can overcome this. The problem is not really the optics: there are lots of fish-eye designs that cover close to 180 degrees field of view.

There are IMAX theaters that cover a hemisphere, but those use multiple projector system, AFAIK.

 

[SAZAR]

Hmm... But, if projectors were using LED light instead of incandescent source, it could solve the problem, right?

 

[Andy Resnick]

LED brightness does not come anywhere near close to arc sources.

 

[SAZAR]

Quote:
"There are IMAX theaters that cover a hemisphere, but those use multiple projector system, AFAIK. "

It would be nice to have one unit which projects upwards and covers even more than half of sphere (some 15m diameter or greater)...

Incandescent light bulbs create more useless wavelengths (infrared) than visible light (somewhere they say that 90% is wasted on heat) - maybe the heat problem in projectors could be solved with filters which pass only visible light to film?

I like those micromirrors projectors... LED technology...

Maybe it's not much of a problem to make even larger surface - based on LED semi-conductors technology, but spread on a greater surface - tightly packed -- that could create strong light...

On the other hand - simple white LEDs could be spread on wide rectangular surface, and then their light could be concentrated on a film with some lenses - right? Hmm, I wonder how large surface would be needed for cinemas?