Tae Won Hahn

US Patent:

6542777, Apr 1, 2003

Filed:

Jan 19, 2001

Appl. No.:

09/766290

Inventors:

Glen A. Griffith - Newbury Park CA
Janusz A. Kuzma - Englewood CO
Tae W. Hahn - Northridge CA

Assignee:

Advanced Bionics Corporation - Sylmar CA

International Classification:

A61N 140

US Classification:

607 57, 607 61, 607137, 607 33, 607 36, 607 60

Abstract:

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 SILBIONEÂLSR 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 SILBIONEÂLSR 70, allowing for a thin and flexible coil.

US Patent:

6745077, Jun 1, 2004

Filed:

Oct 9, 2001

Appl. No.:

09/975042

Inventors:

Glen A. Griffith - Newbury Park CA
Tae W. Hahn - Northridge CA

Assignee:

Advanced Bionics Corporation - Sylmar CA

International Classification:

A61N 108

US Classification:

607 61

Abstract:

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.

US Patent:

20100292759, Nov 18, 2010

Filed:

Mar 24, 2005

Appl. No.:

11/089171

Inventors:

Tae W. Hahn - Northridge CA, US
Richard C. Ross - Westlake Village CA, US

International Classification:

A61F 11/04
A61N 1/375

US Classification:

607 57

Abstract:

Disclosed is a cochlear stimulation system and associated methods that utilizes a magnetic field sensor to determine the status of magnetically-coupled components. The cochlear stimulation system includes an implantable portion positionable beneath the skin of a patient and an external portion positionable outside the skin of the patient. The implantable portion includes a multi-electrode array having a plurality of electrodes configured to be placed in cochlear duct of a patient and an internal magnet. The external portion includes a speech processor configured to generate control signals in response to received sound signals and an external magnet. The external magnet and the internal magnet generate an attractive magnetic force that maintains the external portion in position relative to the internal portion against the scalp of the patient. The cochlear stimulation system further includes a magnetic field sensor configured to sense the value of a magnetic field generated by the external magnet and the internal magnet in order to monitor changes in the magnetic field.

US Patent:

63211181, Nov 20, 2001

Filed:

Jan 27, 2000

Appl. No.:

9/492735

Inventors:

Tae Whan Hahn - Northridge CA

Assignee:

Advanced Bionics Corporation - Sylmar CA

International Classification:

A61N 1378

US Classification:

607 61

Abstract:

A dual directional coupler is placed in the forward power-delivery path of an external transmitter adapted to transmit power to a receiver of an implantable medical device. The dual directional coupler monitors both the forward and reflected (or reverse) power being sent to, and being reflected from, the implantable device. When a valid power link is established between the external transmitter and the implantable medical device, the reflected power falls below a prescribed threshold. When a valid power link does not exist, or when a previously-established power link is broken, then the reflected power rises above the prescribed threshold. The presence of a valid power link is established by monitoring whether the reflected power is above or below the prescribed threshold. The dual directional coupler may be realized using passive discrete circuit components, such as capacitors and inductors; or alternatively using a pair of small transformers, each having a primary and secondary winding wound on a magnetic toroidal core.

US Patent:

51574624, Oct 20, 1992

Filed:

Jan 12, 1990

Appl. No.:

7/475078

Inventors:

Tae Hahn - Chatsworth CA

Assignee:

Litton Systems, Inc. - Beverly Hills CA

International Classification:

G01B 902
H01S 3083

US Classification:

356350

Abstract:

A rotational sensing system for a split gain, multi-mode ring laser gyroscope is disclosed herein that can operate with a simple upright symmetric optics mechanism, where the required signal separation is performed fully electronically. In a preferred embodiment, signal separation circuitry is provided which performs a 180. degree. or. pi. radians phase shift to one of a set of heterodyned signals, A. sub. in, and B. sub. in, with respect to a second set of Split Gain frequency signals, A. sub. out and B. sub. out, in order to extract these Split Gain frequency signals.

US Patent:

52086534, May 4, 1993

Filed:

Aug 6, 1991

Appl. No.:

7/741291

Inventors:

John G. Mark - Pasadena CA
Daniel A. Tazartes - West Hills CA
Tae W. Hahn - Chatsworth CA

Assignee:

Litton Systems, Inc. - Beverly Hills CA

International Classification:

G01B 902

US Classification:

356350

Abstract:

Disclosed herein is a Digitally Controlled Cavity Length Control System comprising, in a preferred embodiment, an adaptive servo-loop for cavity length, modulation depth and amplitude control, and of the multioscillator ring laser gyroscope; thereby, permitting the simultaneous control of these elements. The cavity length control of the multioscillator, by including a variable RF detector gain, allows the operation of the gyroscope in a slightly detuned fashion to minimize magnetic sensitivity. In this manner, the multioscillator gyroscope may be maintained at a stable operating point suitable for modeling.

US Patent:

51969050, Mar 23, 1993

Filed:

Apr 6, 1990

Appl. No.:

7/517644

Inventors:

Tae W. Hahn - North Hollywood CA
Salim N. Jabr - Woodland Hills CA

Assignee:

Litton Systems, Inc. - Beverly Hills CA

International Classification:

H01S 305
G01C 1964
G01B 902
G01P 900

US Classification:

356350

Abstract:

A radio frequency excitation system is disclosed for use in conjunction with a ring laser gyroscope. The radio frequency excitation system is comprised of a closed resonant cavity which surrounds a helical coil driven at a high radio frequency at a range of 5 to 550 megahertz. This closed resonant coil surrounds one leg of a ring laser gyroscope which is carved out and exposed so that it may be surrounded by the resonant cavity. Using such a radio frequency excitation system eliminates the need for high power DC discharge components such as cathodes and anodes, as well as problems inherent with properly sealing the cathodes and anodes to the monolithic frame of the ring laser gyroscope.

US Patent:

62124315, Apr 3, 2001

Filed:

Aug 18, 1999

Appl. No.:

9/376881

Inventors:

Tae W. Hahn - Northridge CA
Glen A. Griffith - Newbury Park CA

Assignee:

Advanced Bionics Corporation - Sylmar CA

International Classification:

A61N 1378

US Classification:

607 61

Abstract:

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.