A mirror comprises a myriad of reflecting surfaces so aligned as to produce a virtual image which may be plain or focused. The surfaces may be irregular in outline to minimize or prevent glint patterns.
BACKGROUND OF THE INVENTION
This application is a continuation of Ser. No. 385,544 filed June 7, 1982, now U.S. Pat. No. 4,470,665 which is a continuation-in-part of Ser. No. 233,106 filed Feb. 10, 1981, (now U.S. Pat. No. 4,368,951), which is a continuation-in-part of Ser. No. 109,970 filed Jan. 7, 1980, now abandoned .
A casting die, for forming a segmented mirror, is formed by the steps including: providing a negative or positive casting of the desired continuous surface shape; cutting the casting into small segments to form non-circular gaps between segment cross-sections; translating the segments relative to one another in a common direction to contact a shaping surface or surfaces, while maintaining constant gap widths between the segments; joining the segments to form a unitary body by adding filler material to the gaps.
An apparatus controls positions of plural mirror segments in a segmented mirror with an edge sensor system and a controller. Current mirror segment edge sensor measurements and edge sensor reference measurements are compared with calculated edge sensor bias measurements representing a global radius of curvature. Accumulated prior actuator commands output from an edge sensor control unit are combined with an estimator matrix to form the edge sensor bias measurements. An optimal control matrix unit then accumulates the plurality of edge sensor error signals calculated by the summation unit and outputs the corresponding plurality of actuator commands. The plural mirror actuators respond to the actuator commands by moving respective positions of the mirror segments. A predetermined number of boundary conditions, corresponding to a plurality of hexagonal mirror locations, are removed to afford mathematical matrix calculation.
