摘要:
A spiral shield for an implantable secondary coil confines the electrical field of the coil, and thus prevents capacitive coupling of the coil through surrounding dielectrics (such as human tissue.) Known implantable devices receive power inductively, through a secondary coil, from a primary coil in an external device. Efficient power reception requires that the coils be tuned to the same resonant frequency. Use of the spiral shield results in predictable electrical behavior of the secondary coil and permits the secondary coil to be accurately tuned to the same resonate frequency as the primary coil. To further improve performance, spacers made from SILBIONE®LSR 70 reside between turns of the coil to reduce turn to turn and turn to shield capacitances. Reducing the capacitances prevents excessive reduction of the self resonant frequency of the coil. The coil is imbedded in SILBIONE®LSR 70, allowing for a thin and flexible coil.
摘要:
A fixed frequency external power source having an external coil is inductively coupled with an implanted coil of an implanted medical device. The implant device has an electronic impedance transformer as part of its load circuit. Such electronic impedance transformer sets a proper voltage and current ratio (impedance) so that the coil set, i.e., the external coil and the implanted coil, are loaded with an optimal load. Such optimal loading, in turn, significantly minimizes any mismatch loss from the inductive link between the external coil and the implant coil, and allows wide ranges in the voltage and load resistance and coil separation, while at the same time maintaining an optimal load condition. The impedance transformer is especially applicable to fully implantable cochlear stimulation systems wherein, during one mode of operation, a relatively large power level must be transferred for charging the implanted power storage element, e.g., a rechargeable battery, but wherein another mode of operation, the implant is operated and powered from an external unit and a relatively small power level is transferred to the implant device. The ratio of these power levels may be large, e.g., about 30 to 1, and unless the coil set, i.e., the external coil and implanted coil, are altered between these different load conditions, a huge mismatch loss may occur, which mismatch greatly reduces the power transfer efficiency. The impedance transformer of the invention minimizes such a mismatch loss.
摘要:
An external power transfer circuit (12) couples ac power having a fixed frequency into an implantable electrical circuit (14), e.g., an implantable tissue stimulator, while automatically maintaining optimum power transfer conditions. Optimum power transfer conditions exist when there is an impedance match between the external and implanted circuits. The external transfer circuit includes a directional coupler (42) and an impedance matching circuit (44). The directional coupler senses the forward power being transferred to the implant device, as well as the reverse power being reflected form the implant device (as a result of an impedance mismatch). The impedance matching circuit includes at least one variable element controlled by a control signal. The sensed reverse power is used as a feedback signal to automatically adjust the variable element in the impedance matching circuit, and hence the output impedance of the external power transfer circuit, so that it matches the input impedance of the implant device, despite variations that occur in the input impedance of the implant device due to variations in implant distance and implant load.
摘要:
An exemplary apparatus for use with an auditory prosthesis system includes a housing, a connector port disposed at least partially within the housing and configured to be communicatively coupled to an auxiliary audio input device, a telecoil disposed at least partially within the housing, and a multi-position switch disposed at least partially within the housing and configured to selectively enable the auxiliary audio input device and the telecoil. The auxiliary audio input device is enabled and the telecoil is disabled when the switch is in a first position, both the auxiliary audio input device and the telecoil are enabled when the switch is in a second position, and the telecoil is enabled and the auxiliary audio input device is disabled when the switch is in a third position. Corresponding apparatuses, systems, and methods are also disclosed.
摘要:
An implantable medical device, such as an implantable cochlear stimulator (ICS) system, utilizes laminated, sectionalized or particle-ized permanent magnets and/or keepers in both the implant portion and external (non-implanted) portion so as to reduce the electrical energy absorbed by both the implant device and the external device when in use. In one embodiment, the implant device employs a sectionalized, laminated or particle-based “keeper”, while the external device employs a sectionalized, laminated or particle-ized magnet, making the implant device immune to being damaged by MRI (magnetic resonance imaging). The combination of the sectionalized/laminated/particle magnets and the sectionalized/laminated/particle keepers creates a very high electrical resistance path across the boundaries of the laminations, sections, or particles, thereby reducing the magnitude of eddy currents that would otherwise flow transversely through the keeper in the presence of a magnetic flux passing through the keeper or magnet. The reduction of eddy currents, in turn, reduces energy loss.
摘要:
Cochlear implant systems include a circuit board having electronic circuitry configured to generate one or more signals configured to direct electrical stimulation of one or more stimulation sites within a patient, an induction coil configured to transmit a telemetry signal by generating a telemetry magnetic field, and a telemetry flux guide positioned between the induction coil and the circuit board. The telemetry flux guide is configured to direct magnetic flux of the telemetry magnetic field away from the circuit board.
摘要:
A discharge-excited waveguide gas laser is disclosed utilizing a transverse rf excitation voltage at a frequency of at least about 30 MHz applied between elongated electrodes on opposite sides of the laser discharge chamber. A plurality of shunt inductances are coupled between the electrodes externally of the chamber at periodically spaced locations along the length of the chamber. These inductances provide a negative admittance which compensates for the variation in the phase angle of the transmission line reflection coefficient along the length of the laser discharge chamber. The variation in the magnitude of the standing wave voltage produced in the chamber by the excitation voltage is reduced accordingly, thereby improving the uniformity of the laser-exciting discharge.
摘要:
The present invention is an improved drum mechanism for use in combination with an automatic photographic processing system which includes a housing, a bi-directional motor that has a shaft and that is mounted on the housing, a control unit for controlling the bi-directional motor and a drain tray that is mounted on the housing. The automatic photographic processing system also includes a fluid injector unit for injecting fluids into said improved drum mechanism that is electrically coupled to the control unit and that is mounted on the housing. The improved drum mechanism includes an elongated, cylinder-shaped member which is adapted to receiver photographic print materials and which is fluidly coupled to the fluid injector unit and a drum mounting that includes a set of four rollers, one of which is mechanically coupled to the shaft of the bi-directional motor and which is mechanically coupled to the elongated, cylinder-shaped member, and that is mechanically coupled to the housing adjacent to the drain tray so that when the elongated, cylinder-shaped member is placed on the set of four rollers it can be bi-directionally rotated by the bi-directional motor. The improved drum mechanism has a draining apparatus which is a slot which travels longitudinally along the sidewall of the elongated cylinder-shaped member and which may be disposed parallelly above the drain tray.
摘要:
A cochlear implant configured to be implanted within a patient may comprise an integrated circuit including a driver configured to generate a back telemetry signal encoded with information to be transmitted over a wireless communication link to a sound processor located external to the patient. The cochlear implant may also comprise a filter network that includes a first plurality of impedance components including a damping resistor, and a first and a second impedance component such as a capacitor or an inductor. The cochlear implant may also comprise an isolation network including a second plurality of impedance components configured to isolate, from the filter network and the driver, a forward telemetry signal received by the cochlear implant from the sound processor.
摘要:
Systems and methods for efficiently transmitting power using a high frequency (e.g., RF) telemetry transmitter are provided. The telemetry transmitter may include a fixed clock source (which may provide a fixed clock signal), telemetry phase shift circuitry (which may include switching circuitry and phase shifting circuitry), and a push-pull network. The telemetry phase shift circuitry generates a phase shifted clock signal that is phase shifted with respect to the fixed clock signal. The fixed and phase shifted clock signals may drive the switching circuitry to produce a high frequency signal that is passed through the push-pull network. The power or magnitude of the high frequency signal is based on the phase delay between the fixed clock signal and the phase shifted clock signal.