Abstract: A fusible link is described. It comprises a semiconductor substrate, an electrically insulating layer on the substrate, a pair of conductor elements on the surface of the insulating layer opposite the substrate, and a fuse conductor layer on the surface of the insulating layer opposite the substrate electrically connecting the conductor elements. A cavity is formed in the insulating layer and the substrate adjacent the fuse conductor layer. The cavity has a configuration to provide a substantial reduction in the thermal conductivity cross-section between the fuse conductor layer and the substrate. Such substantial reduction is selected to enable a predetermined electrical power input to the fuse conductor layer to generate an open circuit in the layer. In a preferred form, the cavity has a configuration to form a bridge comprised of the fuse conductor layer and the portion of the insulating layer upon which the fuse conductor layer is disposed.

Abstract: A trimmable microminiature force-sensitive switching device for detecting the state of external conditions, such as pressure, acceleration and temperature, is disclosed. The device includes a silicon substrate having a reduced-thickness, deflectable member adapted to change its deflection in response to changes in the external condition to be detected. Increasing deflection of the member establishes electrical contact between a common contact and first one, then progressively more, spaced electrical contacts of a plurality of switches. Each of the spaced electrical contacts is connected to a common terminal. Trimming of the switching device is accomplished by application of a preselected external force, such as pressure, that causes the deflection of the deflectable member and the closing of one or more of the switches.

Abstract: A system for monitoring vehicle tire pressure, or the like. The system includes a transmitter and a receiver mounted on the vehicle body, and magnetically coupled inductor and enhancer circuits carried on the vehicle wheel. The inductor circuit contains an open/closed condition switch which is responsive to tire pressure. The transmitter signal, acting through the inductor and enhancer circuits, produces a response voltage in the receiver which varies at a selected transmitter frequency according to the condition of the switch. In one embodiment of the invention, the inductor and enhancer circuits are tuned to enhance the response voltage in the receiver, at a selected transmitter frequency and at one inductor circuit switch condition.

Abstract: A microminiature switch for digitizing different-valued external conditions, such as pressure, temperature of acceleration, is disclosed. The switch includes a silicon wafer having a deflectable, reduced-thickness membrane adapted to move from a relaxed position toward increasingly flexed or bulged positions in response to greater-value changes in such external condition. Movement of the membrane from its relaxed position to more strained positions establishes electrical contact between a common terminal and first one and then progressively more switch-state terminals in the switch, wherein the number of switch states which are closed corresponds to the external condition acting on the switch.

Abstract: Hermetically sealed electrical feedthrough conductors are formed across the periphery or boundary between a hermetically sealed region on a semiconductor substrate and a second or external region thereof by first forming a planar insulative layer on the surface of the silicon substrate along the predetermined path of the feedthrough conductor across the periphery, said insulative layer having at least one planar projection on each side thereof extending out from the path and coming to a point, and then forming thereon a planar metal feedthrough conductor layer that substantially covers the insulative layer, including corresponding metal planar projections. An insulator element sized to encapsulate the region to be sealed is then mallory bonded to the periphery, including the feedthrough conductor, so as to form a hermetic seal along the entire periphery including in the region of said feedthrough conductor.