Printed circuit board projection imaging system

Claim 1

Apparatus for producing printed circuit boards including a projection imaging system for projecting an electrical circuit image from a master onto a radiation sensitive coated printed circuit board panel positioned at a location spaced apart from said master, said projection imaging system comprising: means for generating radiation; first support means for supporting said master, said master having said circuit pattern formed thereon in a predetermined size format, said radiation being incident on said pattern; a projection lens assembly positioned with respect to said master for receiving radiation transmitted through said master and for projecting an image having a size format larger than said predetermined size format onto said radiation sensitive coated printed circuit board panel; second support means for supporting said radiation sensitive coated printed circuit board panel at said spaced apart location; registration means for maintaining said second support means in optical alignment with the image projected from said master, said registration means comprising at least two air bearings for positioning said second support means in first and second axial directions, said two air bearings comprising first and second air bearings positioned at opposite edges of said second support means and operating in a push-pull arrangement to position said second support means in said first and second axial directions, a third air bearing along the lateral edge of said second support means operating to position said second support means in third and fourth axial directions transverse to said first and second axial directions, a fourth air bearing along the same lateral edge of said second support means and adjacent to said third air bearing and operating in synchronization with said third air bearing to position said second support means in said third and fourth axial directions, or independently of said third bearing to provide a rotational adjusting movement to said second support means; said second support means including an illumination source on one side of said printed circuit board panel and a radiation detector on the other side of said printed circuit board panel, said printed circuit board panel having holes associated therewith, the panel being in optical alignment with the image projected from said master when the radiation generated by said illumination source passes through said holes and is detected by said radiation detector; and means for maintaining the spacing between the radiation generating means and the master and the master and the radiation sensitive coated printed circuit board panel substantially constant.