Abstract: In one embodiment of a wireless method of animal control, using animal borne wireless receivers and warning devices, the animal is warned to remain within a lobe of the transmitter station. The lobe is readily moved to facilitate herding and rotational grazing. In another embodiment, the animal is warned not to cross a line (electronic fence) defined between a pair of overlapping lobes of the transmitter station. A third overlapping lobe of radiation provides an electronic gate in the electronic fence by disabling the animal warning device within the localized region of the third lobe. Alternately energizing the pair of overlapping lobes facilitates detection of the electronic fence.

Abstract: A batch method for fabricating semiconductor capacitive force transducers is disclosed wherein a first wafer of silicon or fused silica is recessed by etching to define an array of force transducer structures, each including a deflectable portion supported from a surrounding frame portion. The first wafer is thermoelectrically bonded between a pair of glass or quartz plates, each plate having an array of electrode structures for capacitively sensing deflection of the individual force transducers. Each electrode structure includes a lead portion passing over the frame portion of the transducers and being spaced from the frame to provide a gas communication passageway through the frame to the capacitive gap between the electrode structure and the deflectable portion of each transducer. The composite assembled wafers are notched along cleave lines generally outlining the individual transducer structures.

Abstract: A thermal mass flow meter includes a comb-shaped structure having a plurality closely spaced septa carried from a common spine and disposed within the flow stream to be measured for partitioning the flow therein into a plurality of generally parallel elongated ribbon-shaped flow stream portions. Temperature-dependent fluid flow sensing resistor means is coupled in heat-exchanging relation predominantly with the narrow face of at least one of said ribbon-shaped flow stream portions for measuring the fluid flow. In a preferred embodiment, the comb-shaped flow partitioning structure is fabricated by anisotropically etching the parallel flow channels through the (110) face of diamond cubic material such as silicon.

Abstract: Folded cantilever structures and solid state force transducers using same are made by chemical etching of a semiconductive wafer. In the chemical etching process, an etch stop layer is provided on a wafer of semiconductive material. The etch stop layer is opened in a certain pre-determined pattern and etchant is introduced through the opening in the etch stop layer to produce substantial undercut etching of portions of the etch stop layer. The opening is patterned to define a support structure (frame) for the folded cantilever portion which is undercut. The etch is terminated such that one end of the undercut folded cantilever structure is supported from the frame and the other end terminates on a structure such as a mass that is supported from the frame by means of the folded cantilever structure.

Abstract: Miniature thermal fluid flow sensors of the airfoil type are made in batch form by forming the thermal fluid flow sensors on a thin sheet of material and bonding the sheet over an array of duct structures and dicing the individual sensors and duct structures apart. In one thermal flow sensor configuration, a flow heater is dispsoed inbetween first and second thermal flow sensors in heat exchanging relation therewith. A third thermal flow sensor is disposed upstream of the others out of heat exchanging relation with the heater for operation of the heater at a certain temperature above that sensed by the third sensor. In the low flow regime, flow is measured by the difference between the outputs of the first and second sensors, whereas in the high flow regime, the power required to maintain the temperature of the heater serves as a measure of the flow.

Abstract: A batch method for fabricating semiconductive capacitive force transducers is disclosed wherein a first wafer of silicon or fused silica is recessed by etching to define a array of force transducer structures, each including a deflectable portion supported from a surrounding frame portion. The first wafer is thermoelectrically bonded between a pair of glass or quartz plates, each plate having an array of electrode structures for capacitively sensing deflection of the individual force transducers. Each electrode structure includes a lead portion passing over the frame portio of the transducers and being spaced from the frame to provide a gas communication passageway through the frame to the capacitive gap between the electrode structure and the deflectable portion of each transducer. The composite assembled wafers are notched along cleave lines generally outlining the individual transducer structures.

Abstract: An immersion-type thermal fluid flow sensor is disclosed in which the temperature dependent sensing resistor means is carried from a flexible ribbon-shaped septum immersed in the flow and arranged in a spiral, meander or other geometrical configuration to partition the total flow passageway into a plurality of parallel flow portions. In one embodiment, the partitioned flow passageways are dimensioned to have a length to cross-sectional dimension ratio for providing laminar flow conditions over the operating flow range of interest. In another embodiment, a heater is provided for heating the septum to a temperature near that of the sensing resistor to reduce the time constant of the flow measurement. In another embodiment, a thermal loading element is coupled in heat exchanging relation with the sensing resistors for increasing the critical flow rate and thus for increasing the operating range of the flow regime wherein the temperature difference .DELTA.

Abstract: Miniature thermal fluid flow sensors of the airfoil type are made in batch form by forming the thermal fluid flow sensors on a thin sheet of material and bonding the sheet over an array of duct structures and dicing the individual sensors and duct structures apart. In another embodiment, thin carrier sheet portions of a wafer bearing the thermal fluid flow sensors of the airfoil or grid type are supported by surrounding frame portions of the wafer. The wafer is diced to separate the individual sensing chips. The respective chips are mounted across respective fluid flow ducts. For the airfoil type sensor, portions of the frame are broken away for undisturbed flow over the thin carrier and sensor. In one thermal flow sensor configuration, a flow heater is disposed in between first and second thermal flow sensors in heat exchanging relation therewith.

Abstract: A thermally insulative buoyant swimming pool cover floats on the surface of the pool for covering the pool and for retaining the heat within the pool. Sinking means, such as weights or a mechanical pull-down structure, may be secured to the pool cover along certain predetermined action lines such as fold lines. In one embodiment, an inflatable and deflatable bladder is coupled to the weights. The bladder is dimensioned relative to the weights such that when inflated it overcomes the negative buoyancy of the weights to retain the pool cover in the fully covered position. However, when the bladder is deflated, the weights overcome the positive buoyancy of the cover along the certain fold lines causing the cover to be at least partially pulled below the surface of the pool and folded while at the same time being retracted against one of the side walls of the pool. Pool water is circulated over or through channels of the pool cover to provide solar heating.

Abstract: An etch stopped layer portion overlying a (100) or (110) major face of a diamond cubic semiconductor material is undercut anisotropically etched by orienting a side edge of the etch stopped layer portion which is to be undercut, at an angle to the most nearly parallel {111} trace on the (100) or (110) face. The etch time is further reduced by slotting through the etch stopped layer with slots oriented at an angle to the {111} traces on the underlying (100) or (110) face. Undercut bridge structures are formed by undercutting quadrilateral etch stopped layer portions from opposite sides of the quadrilateral or from the sides plus slots forming diagonals of {111} trace quadrilaterals having combined areas coextensive with the area to be undercut.

Abstract: Three dimensional single crystalline structures, such as folded cantilever beams supported from a frame and supporting a central structure free to move relative to the frame, are fabricated by anisotropically etching through openings in etch stop layers on opposite sides of the substrate wafer. The openings are patterned and aligned so that the etch stop layers are undercut to define etch stop portions interconnected by unetched substrate material.

Abstract: In a miniature valve, a valve seat is formed by aperturing a plate. A cantilever leaf spring is disposed overlying the apertured plate for controlling the flow of fluid therethrough. An electrostatic potential applied between the cantilever leaf spring and the valve plate pulls the leaf spring over the apertured plate for variably controlling flow through the valve in accordance with the magnitude of the applied potential. In a preferred embodiment, the cantilever leaf springs are made in batch form by etching a silicon wafer. A flow controller is provided by measuring the electrical capacitance of the valve, comparing it with a reference voltage and deriving a feedback voltage applied to the valve for controlling flow therethrough. In one embodiment, the width of the cantilever leaf spring valve member is narrowed toward its free end for finer control of flow.

Abstract: A thin film of magnetic recording material is sputter deposited over a base layer of gold and tantalum on a polished substrate. A protective layer of gold and tantalum is deposited overlaying the magnetic recording film. A solid lubricant layer such as carbon, preferably in the form of graphite, gold, silver, tin, molybdenum disulfide, and tungsten disulfide is sputter deposited or ion plated over the protective layer to reduce wear. The recording contacting portion of the recording head is similarly coated with a solid lubricant material. Other suitable protective materials include tantalum, niobium, tungsten and nitrides and carbides of such metals. In a preferred method for making such recording members, the layers are successively sputter deposited in an evacuated sputter chamber, whereby the recording layers and protective coatings are formed in a continuous process requiring only one pump down.

Abstract: A thin film of magnetic recording material is sputter deposited over a base layer of gold and tantalum on a polished substrate. A protective layer of gold and tantalum is deposited overlaying the magnetic recording film. A solid lubricant layer such as carbon, preferably in the form of graphite, gold, silver, tin, molybdenum disulfide, and tungsten disulfide is sputter deposited or ion plated over the protective layer to reduce wear. The recording contacting portion of the recording head is similarly coated with a solid lubricant material. Other suitable protective materials include tantalum, niobium, tungsten and nitrides and carbides of such metals. In a preferred method for making such recording members, the layers are successively sputter deposited in an evacuated sputter chamber, whereby the recording layers and protective coatings are formed in a continuous process requiring only one pump down.

Abstract: A thermally insulative buoyant swimming pool cover floats on the surface of the pool for covering the pool and for retaining the heat within the pool. Sinking means, such as weights or a mechanical pull-down structure, is secured to the pool cover along certain predetermined action lines such as fold lines. In one embodiment, an inflatable and deflatable bladder is coupled to the weights. The bladder is dimensioned relative to the weights such that when inflated it overcomes the negative buoyancy of the weights to retain the pool cover in the fully covered position. However, when the bladder is deflated, the weights overcome the positive buoyancy of the cover along the certain fold lines causing the cover to be at least partially pulled below the surface of the pool and folded while at the same time being retracted against one of the side walls of the pool. Pool water is circulated over or through channels of the pool cover to provide solar heating.

Abstract: A thermally insulative buoyant swimming pool cover floats on the surface of the pool for covering the pool and for retaining the heat within the pool. Sinking means, such as weights or a mechanical pull-down structure, may be secured to the pool cover along certain predetermined action lines such as fold lines. In one embodiment, an inflatable and deflatable bladder is coupled to the weights. The bladder is dimensioned relative to the weights such that when inflated it overcomes the negative buoyancy of the weights to retain the pool cover in the fully covered position. However, when the bladder is deflated, the weights ovecome the positive buoyancy of the cover along the certain fold lines causing the cover to be at least partially pulled below the surface of the pool and folded while at the same time being retracted against one of the side walls of the pool. Pool water is circulated over or through channels of the pool cover to provide solar heating.

Abstract: Solid state dual leaf spring transducers are fabricated by batch photolithographic etching techniques from a monocystalline nonmetallic material, such as silicon. Each leaf spring structure includes a leaf spring portion surrounded by a support structure defined by an intervening region of the wafer disposed between adjacent leaf spring structures etched into the wafer. A pair of such leaf spring structures with their respective surrounding support structures are joined together in mutually opposed relation to form a composite dual leaf spring transducer structure of the type wherein a pair of leaf spring structures are mechanically coupled together in axially spaced relation along an axis of sensitivity for equal displacement along said axis of sensitivity in response to displacement of either one of the spring structures relative to the support structure.

Abstract: A plastic foam rigid swimming pool cover is fabricated by forming an amorphous plastic foam material into a shape conforming generally to the periphery of the pool and into a shape for covering the swimming pool. The cover is also shaped for lifting as an integral unit from a covering position to an uncovered position above the pool via the intermediary of a plurality of lifts such as electric or hydraulic jacks coupled to the pool cover at a plurality of points spaced around the periphery thereof. The amorphous plastic foam material is formed to the desired shape by either casting or spraying the material into or onto a form of proper shape. In some embodiments, the reinforcing members are embedded in the foam to provide added strength and rigidity. The foam cover may include soil and plant receptacles for landscaping. The cover may be formed in situ or at a remote location to a template and segmented for transport to the pool and reassembled in situ.

Abstract: A curved architectural structure is formed by tensioning a membrane into a curved shape and forming an intermediate structure conforming to the contour of the tensioned membrane by applying a rigidizing material such as foam, resin or other lightweight rigidizing material to form a rigidized curved architectural structure or form for same. Cemetitious material having discontinuous reinforcing fibers, as of steel or glass, dispersed therein is applied overlaying a surface of the rigidized structure to shape and support a curved architectural structure of reinforced cemetitious material.

Abstract: A thin film of magnetic recording material is sputter deposited over a base layer of gold and tantalum on a polished substrate. A protective layer of gold and tantalum is deposited overlaying the magnetic recording film. A solid lubricant layer such as carbon, preferably in the form of graphite, gold, silver, tin, molybdenum disulfide, and tungsten disulfide is sputter deposited or ion plated over the protective layer to reduce wear. The recording contacting portion of the recording head is similarly coated with a solid lubricant material. Other suitable protective materials include tantalum, niobium, tungsten and nitrides and carbides of such metals. In a preferred method for making such recording members, the layers are successively sputter deposited in an evacuated sputter chamber, whereby the recording layers and protective coatings are formed in a continuous process requiring only one pump down.