Abstract: Systems and methods are provided for in vivo measurement of pressure. An implantable sensor assembly includes a pressure sensor configured to provide an analog signal representing pressure and a signal conditioning component configured to convert the pressure sensor output into a digital signal. A transmitter is configured to transmit the digital signal to an external base unit. A power control unit is configured to dynamically allocate power throughout the implantable sensor assembly, such that during an active measurement interval of the implantable sensor assembly, each of the pressure sensor, the signal conditioning component, and the transmitter are powered only for a portion of the active measurement interval necessary to perform a related function.

Abstract: A system and method for a Micro Electro-Mechanical System acoustic sensor, or MEMS acoustic sensor, to be used as an implanted microphone for totally implantable cochlear implants or middle ear implants is presented. The MEMS acoustic sensor comprises a coupler that attaches the sensor to an inner part of the ear, a MEMS acoustic sensor that converts acoustic vibrations into a change in capacitance, and a low-noise interface electronics circuit chip that detects the change in capacitance in the MEMS acoustic sensor, creates an signal representing a portion of the acoustic vibrations, and transmits the signal to one or more other devices, such as a cochlear implant. A method of fabrication enables the MEMS acoustic sensor to be fabricated as a small, less than 1 mm3, light weight, less than 30 mg, device suitable for implantation on a structure of the middle ear.

Abstract: An implantable flat blood pressure sensing cuff structure and an implantable blood pressure monitoring device use a first portion of the cuff structure that comprises a sidewall that extends from a surface and contains a pressure sensor, and a second portion of the cuff structure that is configured to overlie and be removably relative to the first portion. The first and second portions of the cuff structure are configured to provide an aperture extending transversely through the cuff structure for receiving a blood vessel therein generally sandwiched between the first portion and the second portion when the second portion is positioned on the first portion such that the pressure sensor is operative to detect vessel expansion and contraction.

Abstract: A method for forming an electrical-conductor-free vapor barrier suitable for protecting long-term implanted electronic systems is disclosed. The method comprises forming a nascent layer of a partially cured layer and repeatedly compressing the layer via a roller-based process. Once the layer has been suitably compressed, the layer is fully cured. In some embodiments, a multi-layer protective layer is formed by repeating the roller-based formation process for each of a plurality of layers. In some embodiments, a multi-layer protective layer comprising layers of different materials is formed.

Abstract: An implantable flat blood pressure sensing cuff structure and an implantable blood pressure monitoring device use a first portion of the cuff structure that comprises a sidewall that extends from a surface and contains a pressure sensor, and a second portion of the cuff structure that is configured to overlie and be removably relative to the first portion. The first and second portions of the cuff structure are configured to provide an aperture extending transversely through the cuff structure for receiving a blood vessel therein generally sandwiched between the first portion and the second portion when the second portion is positioned on the first portion such that the pressure sensor is operative to detect vessel expansion and contraction.

Abstract: Manufacturing all-silicon force sensors, such as capacitive pressure sensors (100, 200) that have long term stability and good linear sensitivity, and can be built into of a pneumatic tire. The sensors include buried electrical feedthrough (112b) to provide an electrical connection into a sealed silicon cavity (108). The buried feedthrough consists of a conductor (112b) in a shallow groove (106) in a substrate (102), communicating between the sensing cavity (108) and an external contact area (110). The sensor designs also feature a method for forming a silicon-to-silicon fusion bond (SFB) wherein at least one of the two surfaces (152, 252) to be has a tough silicon surface unsuitable for good SFB joints because it was bonded heavily boron-doped by means of diffusion. The method of this invention includes preparing each doped surface (152, 252) for SFB by polishing the surface with a Chemical-Mechanical Polishing (CMP) process.

Abstract: A dual output capacitance interface circuit (100) based on switched capacitor circuits and charge subtraction technique provides both voltage output (104) and frequency output (106). The circuit is programmable independently with sensitivity and offset adjustment, and is insensitive to fixed stray capacitance. Temperature compensation methods are described.

Abstract: The rotation of a pneumatic tire is monitored by a self powered tire revolution counter. A piezoelectric (“piezol”) element is mounted in the tire in a manner so as to be subjected to periodic mechanical stresses as the tire rotates and to provide periodic pulses in response thereto. The output of the piezo element is utilized by revolution counting circuitry to count rotations of the tire, as well as by power circuitry to power the revolution counting circuitry.

Abstract: This invention discloses a multi-range fiber-optic reflective micrometer, which comprises a light source for emitting a beam to an object surface, a receiving fiber-optic array, a photo-detector array, and a processor. The processor output a measured value in accordance with a differential signal and a summation signal both derived from the two electric signals corresponding to two adjacent receiving optical fibers which output two sampled lights of stronger intensities as well as a scale voltage. Since the ratio of the differential and the summation signals is proportional to a section of a whole displacement of the object, the whole measuring range could be extended by increasing the number of the receiving optical fibers while its resolution is kept at a degree of deep-sub-micrometer.

Abstract: This invention discloses a multi-range fiber-optic reflective micrometer, which comprises a light source for emitting a beam to an object surface, a receiving fiber-optic array, a photo-detector array, and a processor. The processor output a measured value in accordance with a differential signal and a summation signal both derived from the two electric signals corresponding to two adjacent receiving optical fibers which output two sampled lights of stronger intensities as well as a scale voltage. Since the ratio of the differential and the summation signals is proportional to a section of a whole displacement of the object, the whole measuring range could be extended by increasing the number of the receiving optical fibers while its resolution is kept at a degree of deep-sub-micrometer.

Abstract: An implantable hearing device for improvement of extreme partial and total hearing loss has a transducer mounted to the malleus of the ossicular chain by METABOND adhesive. The device responds to auditory vibrations of the malleus to establish an electrical signal in response thereto. For total hearing loss restoration, a speech processing unit is mounted inside the mastoid cavity having a intracochlear electrode which is inserted into the cochlea through the oval window to reach the nerve endings thereof and transmit speech signals capable of being understood by the brain. For total hearing loss a totally implantable system with a rechargeable battery, receiving antenna for remote control of on/off switch, volume, speech processor and programing is used with a biologic-electronic microphone activated by the implanted rechargeable battery to interact with implanted electronics for transmission of electrical signals from the transducer directly to the cochlear nerve endings.

Abstract: A capacitive absolute pressure sensor. The sensor includes a substrate having an electrode deposited thereon and a diaphragm assembly disposed on the substrate. As pressure increases, the diaphragm deflects, touches the electrode (in the touch mode), and changes the capacitance of the sensor. The changed capacitance is sensed to thus sense pressure changes. A buried feedthrough is used to sense the change in a capacitance in a chamber under the diaphragm and thus determine the pressure sensed. A vacuum in the chamber is maintained by proper selection of a thickness of a sensing electrode and an insulating layer, exposition thereof to a thermal cycle, and the hermetic bonding of the diaphragm assembly to the substrate.

Abstract: A capacitive absolute pressure sensor. The sensor includes a substrate having an electrode deposited thereon and a diaphragm assembly disposed on the substrate. As pressure increases, the diaphragm deflects, touches the electrode (in the touch mode), and changes the capacitance of the sensor. The changed capacitance is sensed to thus sense pressure changes. A buried feedthrough is used to sense the change in a capacitance in a chamber under the diaphragm and thus determine the pressure sensed. A vacuum in the chamber is maintained by proper selection of a thickness of a sensing electrode and an insulating layer, exposition thereof to a thermal cycle, and the hermetic bonding of the diaphragm assembly to the substrate.

Abstract: A system for creating a control signal having a value indicative of the position of the lateral edge of a moving web wherein the system creates a succession of ultrasonic pulses from a transmitter, each of the pulses being created at a known transmit time in response to a transmit signal with the pulses each having a number of oscillations defining a pulse envelope having a pulse start portion. The system directs the ultrasonic pulses toward an ultrasonic receiver along a selected path whereby the position of the lateral edge of the web in the path determines the energy of the pulse as it is received by the receiver and converts the received pulse into an electronic signal having an amplitude determined by the energy of the received pulse. The receiver is spaced from the transmitter a predetermined distance causing the pulses to be received by the receiver at a given time after the transmit signals for a given ambient temperature.

Abstract: There is provided an improvement in a pulsating radiation detector system comprising means in a series circuit for emitting radiation in pulses of a selected, adjusted frequency, means responsive to pulses of radiation at the frequency for creating a control signal related to the received radiation and a driving circuit for pulsating the radiation emitting means in the series circuit. The improvement comprises a modification of the driving circuit to produce voltage pulses in the series circuit at a time base width less than the reciprocal of the frequency (in seconds), with means for sensing current flow in the series circuit, means for limiting current flow in the series circuit and means for adjusting the pulse width continuously as an inverse function of the sensed circuit whereby short distinct pulses can be created for better discrimination and accuracy in the detector system.

Abstract: An implantable intracranial pressure (ICP) telemetry transmitter. Data transmission is accomplished by means of a radio frequency (RF) link coupled to a silicon piezoresistive pressure transducer. Electrostatic bonding of this transducer onto a tubular glass support provides long-term stability, stress isolation and a hermetic package. Because of the large temperature coefficient of the electrostatically bonded pressure transducer (-6 to -9 mm Hg/.degree.C.), a temperature sensor is added to allow temperature compensation to be carried out. Pulse code modulation is employed to assure accurate data transmission. Use of low duty cycle pulse powering techniques lowers the power consumption of the telemeter. The complexity of the electronics is reduced by the use of a custom integrated circuit. Two lithium batteries can provide more than one month of continuous operation and an RF command receiver provides ON/Off control of the telemeter to extend the lifetime of the telemeter.

Abstract: A sensing device for sensing the position of a continuously moving strip of metal and providing a signal for centering the strip on a given line of movement which has good linearity, good stability, and a time stable output. Segments of a pair of capacitor plates overlap each edge of the strip. These are energized by a square wave signal and the variation in capacity between the plates and the strip caused by lateral movement of the strip is detected by a diode bridge and the resultant signal made available to power apparatus for correcting the position of the web.

Abstract: An apparatus for delivering continuous positive airway pressure to a patient (e.g., an infant) includes a cradle assembly for firmly and adjustably supporting the head of a patient to whom continuous positive airway pressure is to be delivered, a support frame assembly mounted on the cradle assembly for adjustably supporting a disposable airway set, and a disposable airway set which receives fresh air and delivers it, under pressure, to a patient. The cradle assembly includes a head-supporting cradle which may be moved to any one of a number of angular positions. A pair of adjustable head-restraining plates are mounted in the cradle for firmly supporting heads of different sizes. The support frame assembly which receives and holds the disposable airway set is mounted on one end of the head-supporting cradle and can be adjusted relative to the cradle for accurate positioning of a nasal cannula at the delivery end of the disposable airway set.

Abstract: A fluidtight, hermetically sealed, miniature transducer adapted to be inserted into the human body and useful for directly monitoring internal fluid or pneumatic pressures within the human body is disclosed. Semiconductor strain gauge elements constituting a piezoresistive bridge are formed by diffusion on the surface of one side of an integral flexible, rectangular, silicon diaphragm area of a single crystal silicon base. A single crystal silicon cover is eutectically bonded to the base by a metallic laminate seal. The base, cover, and seal define an evacuated fluidtight chamber containing the strain gauge elements. Electrical conductors, which include diffused conductor paths under an insulating oxide layer, extend from the piezoresistive bridge to contact pads outside the fluidtight chamber. The contact pads can be connected to a readout device for electrically measuring the pressure differential between the evacuated chamber and fluid external to the transducer as a function of time.