Integrated heater element array and drive matrix

Claim 1

A thermal display comprising: a. an insulating substrate; b. a semiconductor wafer having one face mounted on said insulating substrate by an insulating adhesive, said semiconductor wafer comprising a plurality of physically separated wafer parts forming an array, said wafer parts respectively comprising heat dissipative elements of different heights and widths positioned at said one face to provide overlapping boundaries between adjaCent elements in diagonal and curved line directions, said heat dissipative elements being electrically and thermally isolated from each other, said wafer parts being formed in a first area of said semiconductor wafer; c. means coupled to said heat dissipative elements for selectively energizing said elements; d. a plurality of circuit elements formed on said one face in a second spaced area of said semiconductor wafer, the number of said plurality of circuit elements being at least as large as the number of said plurality of heat dissipative elements, said second area having P-N junctions which electrically isolate said plurality of circuit elements from one another through the semiconductor material, said second area of said semiconductor wafer being integral throughout; e. conductive means located between said one face and said insulating substrate electrically interconnecting said heat dissipative elements and said plurality of circuit elements, said second area being larger than said first area and the number of said plurality of circuit elements being larger than the number of said plurality of heat dissipative elements, said conductive means comprising diffused conductive tunnels in said one face of said semiconductor wafer between said first and second areas of said semiconductor wafer; and f. thermally sensitive means disposed near the opposite face of said semiconductor wafer and thermally coupled to said array of wafer parts.