A semiconductor transducer comprising an improved strain-yielding body yielding a strain in response to the impartation of a force or displacement, and a semiconductor strain gauge bonded to the strain-yielding body. The improved strain-yielding body is made of an iron-nickel-cobalt alloy containing 28.2 to 31.0% by weight of nickel and 15.0 to 19.5% by weight of cobalt. This iron-nickel-cobalt alloy is initially heated up to a temperature above 600.degree. C. for the purpose of standard heat treatment for removing its internal strain. After the standard heat treatment, the iron-nickel-cobalt alloy is subjected to cold working at a working rate of more than and including 60%, and is then subjected to heat treatment at a temperature between 350.degree. C. and 600.degree. C. The heat-treated iron-nickel-cobalt alloy is shaped into the predetermined form of the strain-yielding body.
A strain transducer system 10 and process for making same is disclosed wherein a beryllium-copper ring 13 having four strain gages 12, 14, 26 and 28 disposed thereon and electrically connected in Wheatstone bridge fashion to output instrumentation 25. Tabs 16 and 20 are bonded to a balloon or like surface 11 with strain on the surface 11 causing bending of ring 13 and providing an electrical signal through gages 12, 14, 26 and 28 proportional to the surface strain. FIG. 2 illustrates a pattern of a one-half ring segment as placed on a sheet of beryllium-copper for chem-mill etch formation, prior to bending and welding of a pair of the segments to form a ring structure 13.
A microminiature cantilever structure is provided having a cantilever arm with a piezoresistive resistor embedded in at least the fixed end of the cantilever arm. Deflection of the free end of the cantilever arm produces stress in the base of the cantilever. That stress changes the piezoresistive resistor's resistance at the base of the cantilever in proportion to the cantilever arm's deflection. Resistance measuring apparatus is coupled to the piezoresistive resistor to measure its resistance and to generate a signal corresponding to the cantilever arm's deflection. The microminiature cantilever is formed on a semiconductor substrate. A portion of the free end of the cantilever arm is doped to form an electrically separate U-shaped piezoresistive resistor. The U-shaped resistor has two legs oriented parallel to an axis of the semiconductor substrate having a non-zero piezoresistive coefficient. A metal layer is deposited over the semiconductor's surface and patterned to form an electrical connection between the piezoresistive resistor and a resistance measuring circuit, enabling measurement of the piezoresistive resistor's resistance. Finally, the semiconductor substrate below said cantilever arm is substantially removed so as to form a cantilevered structure, and a tip is connected to the free end of the cantilever arm to facilitate the structure's use in an atomic force microscope.
A strain transducer system 10 and process for making same is disclosed wherein a beryllium-copper ring 13 having four strain gages 12, 14, 26 and 28 disposed thereon and electrically connected in Wheatstone bridge fashion to output instrumentation 25. Tabs 16 and 20 are bonded to a balloon or like surface 11 with strain on the surface 11 causing bending of ring 13 and providing an electrical signal through gages 12, 14, 26 and 28 proportional to the surface strain. FIG. 2 illustrates a pattern of a one-half ring segment as placed on a sheet of beryllium-copper for chem-mill etch formation, prior to bending and welding of a pair of the segments to form a ring structure 13.
The measuring element for a dynamometer consists of a band-shaped substrate of amorphous metal. The band-shaped substrate has one or two necked-down sections on which strain gauge resistors are arranged in the direction of load application. The resistor or resistors may be connected in a bridge circuit together with reference resistors. The load-dependent elongation of the resistors unbalances the bridge circuit to create the desired output measuring signal. Use of a suitable alloy of amorphous metal results in good mechanical characteristic of the measuring element. Specifically, there is a high resistance to creep and to hysteresis effects, while relatively high loads may be measured. Further, such a measuring element is also immune to temperature variations.
A micromachined strain gauge comprising a plastically deformable piezoresistive microstructure formed on a surface of a substrate so that deformation of the substrate plastically deforms the microstructure to thereby change the resistance of the microstructure. The stress in the substrate can be determined from the change in the resistance of the microstructure.
