Method and light collection system for producing uniform arc image size

DETAILED DESCRIPTION In view of the foregoing problems of the conventional systems, it is an object of the present invention to provide an improved collection system which creates an arc image which is independent of the collection angle and which has an improved collection efficiency over the conventional arrangement.
Another object is to provide a collection system in which a smaller system aperture may be used than with the known projector systems.
A farther object of the present invention is to provide an improved collection system that produces a uniform arc image size in all zones for a collimated beam or a non-collimated beam.
Another object is to provide a uniform arc image size from either a spherical or a non-spherical light source.
An additional object is to reduce center obscuration.
In a first aspect according to the present invention, a collection system, provided for a projector, includes a light source, a collector, adjacent the light source, for reflecting light from the light source, and a correcting mechanism, typically adjacent the collector and the light source, for correcting the light and for outputting a light beam having a uniform image size.
With the inventive system, a collimated output beam is produced that prevents coma and spherical aberration.
With a second collection system according to the present invention, the system has a controlled amount of coma which compensates for the apparent change in arc size with collection angle.
This optimizes the collection system for an arc which is not spherical.
Finally, a third system is provided according to the present invention which at least partially corrects center obscuration, as compared to the conventional systems.