Douglas G Kirkpatrick

US Patent:

6353290, Mar 5, 2002

Filed:

Mar 6, 1996

Appl. No.:

08/611899

Inventors:

Chance Glenn - Columbia MD
Roger Kaul - Olney MD
Louis Jasper, Jr. - Fulton MD
George Bergeron, III - Springfield VA
Douglas A. Kirkpatrick - Great Falls VA

Assignee:

The United States of America as represented by the Secretary of the Army - Washington DC

International Classification:

H01J 116

US Classification:

315 3, 313309, 313336, 3151691, 361 42

Abstract:

An apparatus using field emission techniques to limit voltage on RF transmission lines. A voltage limiter comprises a cathode and an anode housed in an airtight tube, whereby the cathode comprises a field emitter array having a plurality of field tips distributed about the surface of an insulating layer, and a microstrip transmission line overlying the insulating layer and having a predetermined width to form electrical contact with a selected group of the field tips. The microstrip transmission line enables propagation of electromagnetic microwave energy over a bandwidth of multiple octaves. The field emitters enable the generation of a flow of electrons at a predetermined breakdown threshold voltage, without the necessity for an external source to induce electron flow. Generation of the electron flow by the field tips creates a reflection wave on the transmission line that interferes with the incident electromagnetic energy to limit the voltage on the transmission line.

US Patent:

6424099, Jul 23, 2002

Filed:

Feb 6, 2001

Appl. No.:

09/776698

Inventors:

Douglas A. Kirkpatrick - Great Falls VA
Gary K. Bass - Mt. Airy MD
Jesse F. Copsey - Germantown MD
Vincent H. Kwong - Vancouver, CA
Izrail Levin - Silver Spring MD
Donald A. MacLennan - Gaithersburg MD
Robert J. Roy - Frederick MD
Paul E. Steiner - Olney MD
Peter Tsai - Olney MD
Brian P. Turner - Damascus MD

Assignee:

Fusion Lighting, Inc. - Rockville MD

International Classification:

H05B 4116

US Classification:

315248, 315246

Abstract:

An ultra bright, low wattage inductively coupled electrodeless aperture lamp is powered by a solid state RF source in the range of several tens to several hundreds of watts at various frequencies in the range of 400 to 900 MHz. Numerous novel lamp circuits and components are disclosed including a wedding ring shaped coil having one axial and one radial lead, a high accuracy capacitor stack, a high thermal conductivity aperture cup and various other aperture bulb configurations, a coaxial capacitor arrangement, and an integrated coil and capacitor assembly. Numerous novel RF circuits are also disclosed including a high power oscillator circuit with reduced complexity resonant pole configuration, parallel RF power FET transistors with soft gate switching, a continuously variable frequency tuning circuit, a six port directional coupler, an impedance switching RF source, and an RF source with controlled frequency-load characteristics. Numerous novel RF control methods are disclosed including controlled adjustment of the operating frequency to find a resonant frequency and reduce reflected RF power, controlled switching of an impedance switched lamp system, active power control and active gate bias control.

US Patent:

6465959, Oct 15, 2002

Filed:

Sep 3, 1999

Appl. No.:

09/380506

Inventors:

Yonglai Tian - Fairfax VA
Douglas A. Kirkpatrick - Great Falls VA
Bradley D. Craig - Cottage Grove MN
John F. Rasmussen - North Potomac MD
Michael G. Ury - Great Barrington MA

Assignee:

Fusion Lighting, Inc. - Rockville MD

International Classification:

H01J 6504

US Classification:

315 39, 315248, 313238, 313110

Abstract:

A screen ( ) including mesh portions ( and ) for a discharge lamp ( ) bears a protective coating which inhibits degradation of the screen under lamp operating conditions. The coating does not absorb microwave energy, is transparent or reflective to visible light, and is capable of protecting the screen for at least several thousand hours of operation without substantial oxidation or tarnishing of the screen. The coating remains on the screen at screen temperatures above about 300 degrees C, and the coating does not significantly crack as the screen heats and cools. The coating may include, for example, a solgel deposited single phase or two phase glass.

US Patent:

6552620, Apr 22, 2003

Filed:

Sep 12, 2001

Appl. No.:

09/949770

Inventors:

Aleksandr Gitsevich - Montgomery Village MD
Douglas A. Kirkpatrick - Great Falls VA
Donald A. MacLennan - Gaithersburg MD

Assignee:

Fusion Lighting, Inc. - Rockville MD

International Classification:

H03B 518

US Classification:

331 99, 331177 V, 331107 DP, 331117 FE

Abstract:

An oscillator includes a solid state active device having an input and an output, a feedback circuit connected from the output of the active device to the input of the active device, the feedback circuit providing suitable positive feedback to initiate and sustain an oscillating condition at a fundamental frequency, and a waveform modifying circuit connected to the output of the active device, wherein the waveform modifying circuit is adapted to modify the waveform on the output in a manner which increases an efficiency of the oscillator. For example, the waveform modifying circuit comprises transmission lines and optionally components which provide a high impedance for odd harmonics of the fundamental frequency. The waveform modifying circuit may further include transmission lines and optionally components which provide a low impedance for even harmonics of the fundamental frequency. The waveform modifying circuit utilize class F amplifier principles to cause the waveform on the output to be relatively more square in shape.

US Patent:

6617806, Sep 9, 2003

Filed:

Feb 6, 2001

Appl. No.:

09/776914

Inventors:

Douglas A. Kirkpatrick - Great Falls VA
James T. Dolan - Frederick MD
Donald A. MacLennan - Gaithersburg MD
Brian P. Turner - Damascus MD
James E. Simpson - Gaithersburg MD

Assignee:

Fusion Lighting, Inc. - Rockville MD

International Classification:

H05B 4116

US Classification:

315248, 315 39, 313113

Abstract:

An electrodeless microwave discharge lamp includes a source of microwave energy, a microwave cavity, a structure configured to transmit the microwave energy from the source to the microwave cavity, a bulb disposed within the microwave cavity, the bulb including a discharge forming fill which emits light when excited by the microwave energy, and a reflector disposed within the microwave cavity, wherein the reflector defines a reflective cavity which encompasses the bulb within its volume and has an inside surface area which is sufficiently less than an inside surface area of the microwave cavity. A portion of the reflector may define a light emitting aperture which extends from a position closely spaced to the bulb to a light transmissive end of the microwave cavity. Preferably, at least a portion of the reflector is spaced from a wall of the microwave cavity. The lamp may be substantially sealed from environmental contamination.

US Patent:

6949887, Sep 27, 2005

Filed:

Oct 12, 2001

Appl. No.:

09/975552

Inventors:

Douglas A. Kirkpatrick - Great Falls VA, US
Aleksandr Gitsevich - Montgomery Village MD, US

Assignee:

Intel Corporation - Santa Clara CA

International Classification:

H05B041/16

US Classification:

315248, 315 5, 315246, 315247

Abstract:

An oscillator includes an amplifier having an input and an output, a feedback network connected between the input of the amplifier and the output of the amplifier, the feedback network being configured to provide suitable positive feedback from the output of the amplifier to the input of the amplifier to initiate and sustain an oscillating condition, and a tuning circuit connected to the input of the amplifier, wherein the tuning circuit is continuously variable and consists of solid state electrical components with no mechanically adjustable devices including a pair of diodes connected to each other at their respective cathodes with a control voltage connected at the junction of the diodes. Another oscillator includes an amplifier having an input and an output, a feedback network connected between the input of the amplifier and the output of the amplifier, the feedback network being configured to provide suitable positive feedback from the output of the amplifier to the input of the amplifier to initiate and sustain an oscillating condition, and transmission lines connected to the input of the amplifier with an input pad and a perpendicular transmission line extending from the input pad and forming a leg of a resonant “T”, and wherein the feedback network is coupled to the leg of the resonant “T”.

US Patent:

20020101190, Aug 1, 2002

Filed:

Dec 14, 2001

Appl. No.:

10/014809

Inventors:

Douglas Kirkpatrick - Great Falls VA, US
Robert Riedell - Clarksville MD, US

International Classification:

H05B041/16

US Classification:

315/246000

Abstract:

An aperture lamp includes a light transmissive envelope enclosing a discharge forming fill which emits light having both a visible light component and an infrared light component, a first reflector structure surrounding the envelope and defining a visible light transmissive aperture, and a second reflector structure surrounding the envelope and defining an infrared light transmissive aperture, wherein the area of the infrared light transmissive aperture is larger than the area of the visible light transmissive aperture.

US Patent:

20020180356, Dec 5, 2002

Filed:

Apr 5, 2002

Appl. No.:

10/116748

Inventors:

Douglas Kirkpatrick - Great Falls VA, US
Donald MacLennan - Gaithersburg MD, US
Tzvetelina Petrova - Springfield VA, US
Victor Roberts - Burnt Hills NY, US
Brian Turner - Germantown MD, US

International Classification:

H01J011/02

US Classification:

313/607000

Abstract:

An electrodeless discharge lamp includes a pair of opposed couplers aligned along an axis, a stationary light transmissive envelope positioned between the pair of opposed couplers, the envelope having an interior length along the axis which is greater than a maximum interior dimension of the envelope orthogonal to the axis, a light emitting fill disposed inside the envelope, the fill including at least one fill substance selected from the group of sulfur, selenium, and tellurium in a concentration of at least 1 mg/cc for each selected fill substance, and a power source connected to the couplers, wherein power applied to the couplers from the power source is effective to initiate and sustain a stable light emitting discharge from the fill. For example, the envelope may be capsule shaped or have the shape of a prolate ellipsoid. The lamp operates at low power and is stable without rotation.