Strain relief technique for surface acoustic wave devices

Claim 2

A surface acoustic wave (SAW) device, comprising: an elastic SAW substrate having a surface with at least one strain sensitive surface area; a cover bonded to the elastic SAW substrate to form a chamber above at least a portion of one of the strain sensitive surface areas of the elastic SAW substrate; a cut extending into the elastic SAW substrate and surrounding a selected surface region of the portion of the strain sensitive surface area which is within the chamber formed by the cover, said cut having a width and a depth sufficient to isolate the selected surface region from surface strains originating outside the selected surface region; at least one acousto-electric coupling means disposed on the isolated surface region; and connector means for electrically connecting each acousto-electric coupling means to electronic circuitry.

Claim 3

A surface acoustic wave (SAW) device comprising: an elastic SAW substrate having a strain sensitive surface with a cut in the surface of the substrate surrounding a region to isolate the region from surface strains originating outside the region; at least one acousto-electric coupling means disposed on the isolated surface region; at least one pair of inner electrical conductors connected to each acousto-electric coupling means and extending over said isolated surface region toward the inner edge of said cut; a matching pair of outer electrical conductors for each pair of inner electrical conductors, each matching pair of outer conductors having one end located on the substrate surface at the outside edge of said cut and having their other end extending out onto the substrate surface for connection to electronic circuitry; and flexible connector means for electrically connecting each matching pair of outer electrical conductors, across said cut, to the corresponding pair of inner electrical conductors on the isolated surface region.

Claim 4

A surface acoustic wave (SAW) device comprising: an elastic SAW substrate having a strain sensitive surface with a cut in the surface of the substrate surrounding a region to isolate the region from surface strains originating outside the region; at least one acousto-electric coupling means disposed on the isolated surface region; at least one pair of inner electrical conductors connected to each acousto-electric coupling means and extending over said isolated surface region toward the inner edge of said cut; a matching pair of outer electrical conductors for each pair of inner electrical conductors, each matching pair of outer conductors having one end located on the substrate surface at the outside edge of said cut and having their other end extending out onto the substrate surface for connection to electronic circuitry; and flexible connector means for electrically connecting each matching pair of outer electrical conductors, across said cut, to the corresponding pair of inner electrical conductors on the isolated surface region.

Claim 5

A surface acoustic wave device comprising: a substrate having a surface of piezoelectric material; a cover bonded to the substrate to form a chamber above the piezoelectric material; a cut extending into the substrate surface enclosing a surface region of the piezoelectric material within said chamber, said cut having a width and depth sufficient to isolate said enclosed surface region from surface strains originating outside said enclosed surface region; at least one acousto-electric coupling means disposed on the piezoelectric surface in said enclosed surface region; electrical conductors extending from the outside to the inside of said chamber; and flexible electrical connectors extending across said cut for electrically connecting said electrical conductors to said acousto-electric couplers across said cut.

Claim 6

A surface acoustic wave device comprising: a substrate having a surface of piezoelectric material; a cover bonded to the substrate to form a chamber above the piezoelectric material; a cut extending into the substrate surface enclosing a surface region of the piezoelectric material within said chamber, said cut having a width and depth sufficient to isolate said enclosed surface region from surface strains originating outside said enclosed surface region; at least one acousto-electric coupling means disposed on the piezoelectric surface in said enclosed surface region; electrical conductors extending from the outside to the inside of said chamber; and flexible electrical connectors extending across said cut for electrically connecting said electrical conductors to said acousto-electric couplers across said cut.

Claim 7

The surface electro-acoustic wave device as recited in claim 3 wherein said cut has a depth of between 25% to 75% of the thickness of the substrate.