Abstract: This disclosure provides a novel flow device having a fourth root pressure versus flow characteristic. The flow device includes an inlet, an orifice that focusses fluid pressure, a pair of parallel plates (or other surfaces which can be modeled as parallel plates), and an outlet. Preferably, the pair of parallel plates are a pair of two flat disks, one of which has a central aperture. When the device is used as a flow restrictor, the central aperture forms a seat against which the second plate (the impeder plate) is biased to restrict fluid flow. The orifice provides fluid pressure through the aperture, which forces the second plate away from the first plate, and against the bias. Fluid flow through the plates is directly proportional to displacement between the plates, and spent fluid escapes via a radial periphery of the second plate. Preferably, the second plate is mounted to a housing by a set of springs which also contain a strain gauge, such that displacement can be electronically measured.

Abstract: A flexible and efficient bulk micromachining method for fabricating a novel microstructure that is bounded by substantially planar surfaces meeting only at substantially right angle corner features. The novel microstructure of the present invention is useful as a spacer in assembly processes where high accuracy is required, such as precise positioning of optical fibers or conductors. In the preferred embodiment, the microstructure of the present invention includes a shelf feature disposed along a height dimension of the microstructure, which is required for some applications.The bulk micromachining method of the present invention includes providing a first substrate having a top planar surface and an opposing planar surface. The opposing surface of the substrate is anisotropically etched to provide a first thinned region. The top surface of the first substrate is anisotropically etched so that a first recessed feature having a vertical side is made integral with the first thinned region.

Abstract: A switching element defines a transmitting state and a reflecting state for a pair of intersecting waveguides that have a gap at their intersection. In the preferred embodiment, the switching element exhibits total internal reflection at the gap sidewall from one waveguide to the other when not in the transmitting state. In the transmitting state, index-matching liquid fills the gap, enabling light to continue in the original waveguide direction. The switching element may use ink jet techniques or bubble techniques to displace index-matching liquid. The index-matching fluid may be projected from a gap between the waveguides by a jet mechanism, or a vapor or dissolved gas bubble may be formed to fill the gap between the waveguides to provide the reflecting state for the switching element. Using either of the techniques, heaters are employed to initiate the switching operation. In some embodiments, more than one heater is utilized.

Abstract: A semiconductor flow sensor provides a self-aligning seal between the sensor and a manifold carrying the fluid being measured. The sensor includes a sensing element and a semiconductor body having a fluid flow region formed therein. The sensing element crosses through a portion of the flow region and is supported by the semiconductor body. A characteristic of the fluid flowing through the flow region is measured by operation of the sensing element. A sealing ring integrally disposed on the semiconductor body surrounds the flow region and further provides a seal between the sensor and a manifold. To ensure accurate placement of the sealing ring with respect to the sensing element, the sealing ring is electroplated to the semiconductor body prior to formation of the flow region. A pressure and temperature stable seal between the sensor and the manifold is achieved by either compression of the sealing ring, or solder bonding of the sealing ring to the manifold.

Abstract: A microminiature valve includes a crystalline substrate having a flow via and a raised valve seat structure. The valve seat structure has a planar bearing surface. The inner edge of the bearing surface defines an orifice to the flow via. The flow via has a varying cross sectional area and is narrowest at the orifice. From both the inner and outer edges of the bearing surface, parallel sloped walls along {111} planes are formed by an anisotropic etch. The microminiature valve has a high ratio of the area of the flow via at the orifice to the area within the outer edges of the valve seat structure.

Abstract: An electromechanical sensor is provided which comprises: first semiconductor wafer including a first stop surface residing in a first shallow recessed region of the first wafer; a second semiconductor wafer; wherein the first and second semiconductor wafers are laminated together such that the first recessed region of the first wafer and the second wafer define a first chamber in which the first stop surface and the second wafer are disposed close enough together such that the first stop surface restrains the second wafer from deflecting beyond the first stop surface; and an apparatus for measuring deflection of the second wafer.

Abstract: An electromechanical sensor is provided which comprises: a first silicon wafer which defines a resonant element; wherein the resonant element is doped with approximately the same impurity concentration as a background dopant concentration of the first wafer; and a second single crystal wafer which defines a device for coupling mechanical stress from the second wafer to the resonant element; wherein the first and second wafers are fusion bonded together.

Abstract: A microminiature valve having radially spaced, layered spider legs, with each leg having first and second layers of materials having substantially different coefficients of thermal expansion. The legs include heating elements and are fixed at one end to allow radial compliance as selected heating of the legs causes flexure. Below the legs is a semiconductor substrate having a flow orifice aligned with a valve face. Flexure of the legs displaces the valve face relative to the flow orifice, thereby controlling fluid flow through the orifice.

Abstract: A force or pressure sensor includes a monocrystalline silicon diaphragm coated with silicon dioxide upon which single crystalline silicon resistors are fused in a low profile pattern on the surface. The resistors are almost perfectly electrically isolated from each other and from the underlying silicon substrate. The structure is fabricated by forming resistors in a first wafer and then affixing that surface of the first wafer to the silicon dioxide layer on the second wafer. All of the first wafer except for the resistors has been removed, and metal contact capable of resisting elevated temperatures are formed to provide electrical connections to the resistors.

Abstract: A micromachined accelerometer includes integral bidirectional shock protection and controllable viscous damping. The accelerometer includes a frame in which a seismic mass is disposed and coupled to the frame by one or more cantilever beams. Upper and lower stops are provided around the periphery of the seismic mass and around the interior of the frame to limit the travel distance of the seismic mass. The accelerometer is fabricated, preferably from monocrystalline silicon, by defining an annular recess which extends into a first surface of a silicon substrate. Next, a layer is formed over the surface of the substrate but not in contact with the lower surface of the recessed region. An annular-shaped region of the substrate extending from the bottom surface of the substrate to the layer is then removed to define the seismic mass and frame. Finally, portions of the layer are removed to define the cantilever beams and integral bidirectional stops.

Abstract: A semiconductor pressure transducer includes a silicon substrate, a recessed portion in a major surface of the substrate, and a multiple level diaphragm overlying the recessed portion. A selectively etchable spacer material is employed when fabricating the diaphragm by forming successive layers of diaphragm material over the spacer material. Holes through the diaphragm are filled with the selectively etchable material thereby allowing the etching of the spacer material. Support posts can be provided in the recessed portion to help support the diaphragm.

Abstract: A method of forming a flexible array of circuit elements and electrical contacts where parallel lines of conductors joined by short perpendicular line of conductors are folded both about an axis parallel to the perpendicular line of elements and about an axis parallel to parallel lines thereby forming a linear array.

Abstract: A comb filter including a first plurality of generally parallel grooves and a capillary including a second groove connected to the first plurality of grooves are integrally formed in a substrate such as by selective etching a surface of a semiconductor substrate. A cover is affixed to the surface and covers the etched grooves. An input line is connected to the filter and an output line is connected to the capillary. A second comb filter can be included in the output line.

Abstract: Improved contacts to a semiconductor device such as a plural substrate pressure sensor are provided by forming recessed contact regions along the periphery of a semiconductor substrate and interconnecting the contact regions with an internal circuit. A second, glass substrate encapsulates the circuit and covers the recessed contact regions thereby defining tunnels in the edges of the device. A pre-tinned wire can be inserted into a tunnel and solder bonded to a metal layer therein, thereby forming a single and rugged lead attachment.

Abstract: A method for investigating the quality of dielectrically isolated thin film emiconductor layers in inversion-mode MOS devices having dual-gate control capabilities which allow two channels to be created in the semiconductor film. With one channel conducting and a drain voltage providing operation in the saturation region, a step voltage is applied to the gate associated with the second channel which has a transient effect on the current in the first channel. This transient may be analyzed to measure the generation lifetime and other parameters in the body of the device.