HIGH TEMPERATURE, HIGH VACUUM, DIFFUSION BONDED PIEZOELECTRIC MOTOR SANDIWCH, UTILIZING INTERMEDIATE WAFFLELIKE LAYERS

• US 3,573,511 A
• Filed: 06/05/1969
• Issued: 04/06/1971
• Est. Priority Date: 01/04/1968
• Status: Expired due to Term

• Current Assignee: Don W. Noren
• Original Assignee: Don W. Noren
• Inventors: Noren, Don W.
• Application Number:
  US04/830,680
• Time in Patent Office: 670 Days
• US Class Current: 310/364
• CPC Class Codes: H10N 30/073 by fusion of metals or by adhesives
• CPC Class Codes: H10N 30/204 using bending displacement, e.g. unimorph, bimorph or multimorph cantilever or membrane benders
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

This invention presents a construction for piezoelectric-type motor devices commonly termed '"'"''"'"''"'"''"'"'bimorphs'"'"''"'"''"'"''"'"' and obtains an improved bimorph that is suitable for operation at high temperatures and in high vacuum environments. The bimorph is constructed of two thin flat piezoelectric layers, each of which is plated on the front and back faces with an electrically conductive material by conventional techniques, such as ion plating. This plating preferably consists of successive layers of chrome, copper, and gold. One face of each element functions as an outer electrode. The middle electrode of the bimorph is a thin flat metal which has physical characteristics which match those of the piezoelectric bodies, suitably molybdenum. The molybdenum sheet is copper plated on both sides. This electrode is sandwiched between the two piezoelectric layers. However, sandwiched between each of the piezoelectric layers and the plated middle electrode is a thin layer of electrically conductive material, suitably gold, having a wafflelike or indented lattice surface configuration. These elements are sandwiched together as indicated and are diffusion bonded together to form a unitary mass. One representative application is the use of the bimorph as a driving mechanism in tuners located within the evacuated regions of microwave tubes, such as the coaxial magnetron. Additionally, because the construction retains its operational characteristics in high vacuum environments without outgassing, the motor mechanism is suitable for application in high vacuum electron tubes and in outer space.

Claims

2. The invention as defined in claim 1, further comprising:

d. a fourth thin layer of piezoelectric material having some surface unevenness plated with conductive material on the front and back sides thereof; and

e. means uniting together said fourth layer and the remaining side of said second layer comprising a fifth thin metal layer of electrically conductive material having an indented lattice configuration sandwiched between and metal-to-metal bonded to said second and fourth layers to from therewith a unitary mass.

3. The invention as defined in claim 1 wherein said plating of conductive material on said first thin layer comprises a layer of chrome, a layer of copper, and a layer of gold;

and wherein said second thin layer of conductive material comprises molybdenum material plated with copper, and said third thin layer of conductive material comprising gold.

4. The invention as defined in claim 2 wherein said plating of conductive material on said first and fourth thin layers of piezoelectric material comprises a layer of chrome, a layer of copper, and a layer of gold;

and wherein said second thin layer of conductive material comprises molybdenum plated on the front and back sides thereof with a layer of copper; and

wherein said third and fifth thin layers of conductive material comprises gold.

5. The process of forming a union between a plated thin brittle piezoelectric layer having some surface unevenness and a thin plated metal body having some surface uneveness and rigidness comprising the steps of:

inserting a second thin metal body between said piezoelectric body and said metal body, said second metal body having an indented lattice surface configuration; and

diffusion bonding said members together.