Bias field apparatus for magnetic domain memory device

Claim 2

An improved magnetic bias field apparatus comprising: a. a first assembly including i. a first magnet means for establishing a magnetic pole over a first planar area, and ii. a first magnetically permeable plate contiguous to and generally coextensive with the first planar area; b. a second assembly including i. a second magnet means for establishing a magnetic pole over a second planar area, and ii. a second magnetically permeable plate contiguous to and generally coextensive with the second planar area; and c. spacing means for holding said first and said second assemblies in generally parallel relationship with said first and said second magnetically permeable plates being between said first magnet means and said second magnet means.

Claim 3

An improved bias field apparatus as recited in claim 1 wherein said first and said second magnet means are made of permanently magnetized materials.

Claim 4

An improved bias field apparatus as recited in claim 2 wherein said spacing means includes means for varying the separation of said first and said second assemblies.

Claim 5

For use in a magnetic domain memory device including domain material chips mounted on substrates and an orthogonal drive coil assembly surrounding the substrates, an improved bias field apparatus comprising: a. an upper assembly including i. a first permanent magnet having dissimilar magnetic poles at opposite major surfaces, and ii. a first magnetically permeable plate contiguous with one major surface of said first permanent magnet; b. a lower assembly including i. a second permanent magnet having dissimilar magnetic poles at opposite major surfaces, and ii. a second magnetically permeable plate contiguous with one major surface of said second permanent magnet; and c. spacing means for holding said upper assembly and said lower assembly in generally parallel relationship on opposite sides of the drive coil assembly with said first and said second magnetically permeable plates being between said first permanent magnet and said second permanent magnet and with dissimilar magnetic poles of said first and second slab magnets being adjacent.

Claim 6

For use in a magnetic domain memory device including domain material chips mounted on substrates and an orthogonal drive coil assembly surrounding the substrates, an improved bias field apparatus comprising: a. an upper assembly including i. a first permanent magnet having dissimilar magnetic poles at opposite major surfaces, and ii. a first magnetically permeable plate contiguous with one major surface of said first permanent magnet; b. a lower assembly including i. a second permanent magnet having dissimilar magnetic poles at opposite major surfaces, and ii. a second magnetically permeable plate contiguous with one major surface of said second permanent magnet; and c. spacing means for holding said upper assembly and said lower assembly in generally parallel relationship on opposite sides of the drive coil assembly with said first and said second magnetically permeable plates being between said first permanent magnet and said second permanent magnet and with dissimilar magnetic poles of said first and second slab magnets being adjacent.

Claim 7

An improved bias field apparatus as recited in claim 4 wherein said first and second magnetically permeable plates are laminar in construction.

Claim 8

An improved bias field apparatus as recited in claim 4 wherein said spacing means includes means for varying the separation of said first and said second assemblies.

Claim 9

An improved bias field apparatus as recited in claim 4 wherein said lower assembly includes a predetermined number of threaded openings, said upper assembly includes a like number of openings, each of which is aligned with one of the threaded openings in the lower assembly, and said spacing means comprises a like number of nonmagnetic bolts, each having a threaded shank extending into one of the threaded openings in the lower assembly and a head portion rotatable within but axially immovable with respect to the aligned opening in said upper assembly.

Claim 10

An improved bias field apparatus as recited in claim 7 wherein the number of nonmagnetic bolts and the number of openings in each of the upper and lower assemblies is four.

Claim 11

An improved bias field apparatus as recited in claim 7 wherein said first and second magnetically permeable plates are laminar in construction.

Claim 12

An improved bias field apparatus as recited in claim 8 wherein each of the upper and lower assemblies in rectangular and wherein the aligned openings and the nonmagnetic bolts are located near the corners of the rectangles.