Line drawing photoexposure device with image rotating means

Claim 1

A photoexposure mechanism for exposing lines on a photosensitive surface by means of a light spot moved thereover, said mechanism comprising means defining a supporting surface for supporting a piece of material having a photosensitive surface, and a photoexposure device supported for movement relative to said supporting means in a plane generally parallel to said Supporting surface, said photoexposure device comprising an aperture, means for illuminating said aperture, and an optical imaging system for forming an image of said aperture on said photosensitive surface which image is a substantially undistored optical reproduction of said aperture and constitutes the aforesaid spot which is moved over said photosensitive surface to expose lines thereon as a result of movement of said photoexposure device relative to said supporting surface, the path of light rays through said optical imaging system including at least one zone of non-parallel light rays, and an image rotator capable of rotating said non-parallel light rays, said image rotator being located in said zone of non-parallel light rays for rotating said image relative to said photosensitive surface, said imaging system comprising a lens located between said aperture and said photosensitive surface and said image rotator being located between said aperture and said lens, said image rotator comprising a mirror assembly defining an odd number of planar reflecting surfaces encountered successively by a light ray passing through said assembly and arranged to deflect such a ray traveling along the optical axis of said rays first away from and then eventually back to a straight line colinear with said optical axis as said optical axis enters said mirror assembly, and means for rotating said mirror assembly about said given straight line, said photoexposure device also including a first support member to which said mirror assembly is fixed, a second support member, means attaching said first support member to said second support member and permitting said first support member to be manually adjusted relative to said second member to shift said first support member toward and away from said given straight line along a first line perpendicular to said straight line and to vary the inclination of said first support member relative to said straight line in the plane defined by said first line and said given straight line, a third support member, means attaching said second support member to said third support member and permitting said second support member to be manually adjusted relative to said third member to shift said second support member toward and away from said given straight line along a second line perpendicular to both said given straight line and first line and to vary the inclination of said second support member relative to said given straight line in the plane defined by said second line and said given straight line, and a main frame, said means for rotating said mirror assembly including means mounting said third support member to said main frame for rotation relative to said main frame about said given straight line.