초록 ▼

A specimen or in-service structural member in which strain is to be measured is fabricated as a unit which generates a signal in response to strain occurring in a given region of its surface. A film of piezoelectric material is deposited upon the surface in a manner providing a strong molecular bond

A specimen or in-service structural member in which strain is to be measured is fabricated as a unit which generates a signal in response to strain occurring in a given region of its surface. A film of piezoelectric material is deposited upon the surface in a manner providing a strong molecular bond between the specimen or member and the piezoelectric film. The film material is chosen from the class having a 6 mm type crystal lattice structure and is formed as a crystalline deposit with the c-axis perpendicular to the surface of the specimen or member. An arrangement of electrodes is provided for direct electrical coupling between spatially separated portions of the piezoelectric film. The electrodes form an output coupling for an electrical signal generated by the piezoelectrically active properties of the piezoelectric film in response to strain mechanically coupled from the substrate surface to the piezoelectric film through the molecular bond. In constructions in which there is a possibility of the electrode arrangement becoming short-circuited through minute vacancies present as imperfections in the piezoelectric film, an ultrathin film of insulating material is deposited adjacent one or the other sides of the piezoelectric film.

대표청구항 ▼

Signal generating apparatus responsive to strain in a given region of a body member, said apparatus comprising: a. a body member having a substrate surface formed along the exterior thereof in the region from which a signal is desired, b. a piezoelectric film affixed upon said substrate surface, sai

Signal generating apparatus responsive to strain in a given region of a body member, said apparatus comprising: a. a body member having a substrate surface formed along the exterior thereof in the region from which a signal is desired, b. a piezoelectric film affixed upon said substrate surface, said piezoelectric film being made of a crystalline material having a predetermined crystal lattice structure characteristic, c. output signal coupling means for direct coupling of an electrical signal generated by the piezoelectrically active properties of said piezoelectric film between selected spatially separated portions of said piezoelectric film, d. said output signal coupling means comprising an arrangement of first and second electrodes in spaced relationship in the thickness dimension the the piezoelectric film, e. said body member being made of a conductor material and forming said first electrode, f. a conductor disposed adjacent to and in signal coupling relationship to the outer face of the piezoelectric film, said conductor forming said second electrode, g. insulating film means cooperative with said piezoelectric film to obviate possible short circuit effects between the conductor and the body member which may be caused by portions of said conductor extending into minute vacancies which may be present as imperfections in the piezoelectric film, h. said insulating film means comprising an insulating film interposed between the outer face of the piezoelectric film and the adjacent conductor, and i. the thickness of said piezoelectric film being no greater than 1.5 microns and the thickness of said insulating film being of no more than about 500 Angstroms. Signal generating apparatus responsive to strains occurring in a given region of a body member, said apparatus comprising: a. a body member of a conductive material having a zone of its exterior surface adapted to receive in molecularly bonded relationship thereto a deposit of a different solid-state material, said zone adjoining the region of the body member from which a signal responsive to strain is desired, b. a dual layered arrrangement of solid-state films affixed to the body member on said zone prepared for receiving solid-state material, said dual layered arrangement comprising an inner film layer made of insulator material and an outer film layer made of piezoelectric material, c. said inner insulator film layer being deposited onto the body member by a vapor deposit-type process to effect the formation of the inner insulator film layer as a stratum of solid-state material in molecularly bonded relationship to the body member, d. said outer piezoelectric film layer being deposited onto the outer surface of the inner insulator film layer by a vapor deposit-type process to effect the formation of the outer piezoelectric film layer as a stratum of crystalline piezoelectric material in molecularly bonded relationship to the inner insulator film layer, e. a pair of electrodes comprising said body member forming one electrode of the pair and a conductor element affixed to the outer surface of said outer piezoelectric film layer forming the other electrode, said pair of electrodes being operative to pick off an electrical potential generated by the portion of the outer piezoelectric film layer disposed therebetween, and f. said inner insulator film layer sealing minute vacancies which may be present as imperfections in said outer piezoelectric film layer to obviate presence of a low impedance electrical path between the body member and the conductor element, whereby said dual layered arrangement composed of said inner and outer film layers constitutes a high internal impedance source of piezoelectric signals.