Optical alignment system

Claim 1

AN ALIGNMENT APPARATUS FOR CONTINUOUSLY MAINTAINING A WORKPIECE IN A PRECISE PREDETERMINED POSITION COMPRISING, IN COMBINATION: (A) ELECTRO-OPTICAL MEANS FOR DETERMINING THE POSITION OF SAID WORKPIECE AND GENERATING ELECTRIC SIGNALS THAT INDICATE THE POSITION THEREOF; (B) COMPUTER MEANS ELECTRICALLY CONNECTED TO SAID OPTICAL MEANS FOR RECEIVING THE ELECTRIC SIGNALS FROM SAID OPTICAL MEANS AND GENERATING AN ERROR SIGNAL WHEN THE WORKPIECE IS OUT OF POSITION; (C) MOVABLE SUPPORT MEANS ON WHICH SAID WORKPIECE IS MOUNTED THAT ARE ELECTRICALLY CONNECTED TO SAID COMPUTER AND ACTUATED BY THE ERROR SIGNAL THEREFROM TO REPOSITION THE WORKPIECE; (D) SAID ELECTRO-OPTICAL MEANS INCLUDING: (1) INSTRUMENT MEANS FOR PROJECTING TOWARD THE WORKPIECE A LIGHT BEAM PATTERN HAVING THE FORM OF A RADIAL SECTOR OF LIGHT THAT ROTATES ABOUT A FIRST OPTICAL AXIS OF THE INSTRUMENT MEANS, (2) MEANS MOUNTED ON SAID WORKPIECE FOR REFLECTING THE LIGHT BEAM PATTERN BACK TO SAID INSTRUMENT WITH THE RADIAL SECTOR OF LIGHT ROTATING ABOUT A FIRST AXIS OF ROTATION THAT NORMALLY COINCIDES WITH THE FIRST OPTICAL AXIS, SAID FIRST AXIS OF ROTATION COINCIDING WITH THE FIRST OPTICAL AXIS WHEN SAID WORKPIECE IS IN ALIGNMENT, BUT BEING DISPLACED THEREFROM WHEN SAID WORKPIECE IS OUT OF ALIGNMENT, (3) BEAM SPLITTER MEANS MOUNTED IN SAID INSTRUMENT FOR DEFLECTING SAID REFLECTED LIGHT BEAM PATTERN ALONG A SECOND AXIS OF ROTATION NORMAL TO THE FIRST AXIS OF ROTATION OF SAID REFLECTED LIGHT BEAM PATTERN. (4) A PLURALITY OF PHOTOELECTRIC MEANS MOUNTED IN SAID INSTRUMENT AND POSITIONED IN A CIRCULAR ARRAY WHOSE CENTER COINCIDES WITH A SECOND OPTICAL AXIS NORMAL TO THE FIRST OPTICAL AXIS OF SAID INSTRUMENT MEANS; SAID SECOND AXIS OF ROTATION COINCIDING WITH THE SECOND OPTICAL AXIS WHEN THE WORKPIECE IS IN ALIGNMENT BUT DISPLACED THEREFROM WHEN THE WORKPIECE IS OUT OF ALIGNMENT; WHEREBY SAID PHOTOELECTRIC MEANS WILL GENERATE A SERIES OF ELECTRIC SIGNALS WHOSE TIME SEQUENCE INDICATES THE RELATIVE POSITIONS OF THE OPTICAL AXIS OF ROTATION.