Richard A Dorman

US Patent:

6809542, Oct 26, 2004

Filed:

Oct 3, 2002

Appl. No.:

10/263952

Inventors:

Richard Dorman - Wynantskill NY

Assignee:

MTI Instruments Inc. - Albany NY

International Classification:

G01R 3126

US Classification:

324765, 324760

Abstract:

Apparatus for non-contact determination of wafer resistance of a semiconductor wafer includes a first sensor element, separated from a surface of the wafer by a first air gap, for capacitively coupling an AC drive signal into a portion of the wafer. A second sensor element, separated from the surface of the wafer by a second air gap, capacitively couples an AC output signal out of the wafer portion. An inductor, in series connection with the sensor elements is included in the sensor/wafer circuit. A frequency of the AC drive signal is automatically tuned to a resonant frequency at which capacitance impedance of the first air gap and of the second air gap is canceled by inductive impedance of the inductor. A voltage value of the drive signal required to drive an AC current signal of fixed magnitude through the wafer portion is automatically determined. The voltage value provides a measure of wafer resistance.

US Patent:

40672255, Jan 10, 1978

Filed:

Mar 21, 1977

Appl. No.:

5/779748

Inventors:

Richard A. Dorman - Troy NY
Curtis D. Kissinger - Gloversville NY
Lawrence J. Lagace - Albany NY

Assignee:

Mechanical Technology Incorporated - Latham NY

International Classification:

G01B 722
G01H 1100

US Classification:

73 1DV

Abstract:

A new capacitance type non-contact displacement and/or vibration measurement instrument sensing head is described together with a novel method of maintaining calibration of the instrument using such sensing head. The invention takes the form of a central probe member having a first guard ring disposed in coaxial, electrically insulated relationship about the central probe member and driven at the same potential and frequency as the probe member. A secondary driven guard ring coaxially surrounds the first guard ring and is electrically isolated from it and is driven at the same alternating current frequency but at a higher voltage of the order of 1. 5 to 1 times higher. The additional secondary guard ring, driven at a suitably boosted voltage level and the same frequency as the central probe member, serves to focus the otherwise divergent electric field, thus producing a very significant improvement in the output linearity when operated at relatively large displacements. Experiments have shown that a probe in accordance with the invention of 1 inch overall diameter can now be used to measure displacements up to approximately 1 inch, whereas previously a probe of the similar outside diameter could be used to measure displacements of only approximately 1/10 of an inch, unless some form of electronic linearization of its output was employed. With the improved sensing head assembly of this invention calibration of the instrument can be more easily maintained by simply removing the probe from a measurement position, applying a ground potential to the secondary guard ring and adjusting the output of the instrument to a fixed reference value to thereby recalibrate the instrument.

US Patent:

43532209, Oct 12, 1982

Filed:

Jun 17, 1980

Appl. No.:

6/160429

Inventors:

Peter W. Curwen - Ballston Spa NY
Richard A. Dorman - Troy NY

Assignee:

Mechanical Technology Incorporated - Latham NY

International Classification:

F04B 4906
F25B 4104

US Classification:

62228

Abstract:

A method and apparatus for controlling a resonant piston compressor of the type comprising an electrodynamic linear reciprocating motor adapted to be driven cyclically by an alternating current power source and having at least one piston coupled to and adapted to be driven within a selectively valved working cylinder by the linear reciprocating motor in synchronism with the frequency of the alternating current power source. Enclosed volumes of gas act as resilient gas springs coacting with the piston and with the linear reciprocating motor to form a mechanical resonant system having a resonant frequency substantially centered on the frequency of the alternating current power source. A midstroke porting arrangement is responsive to the position of the resonant piston for selectively communicating a gas spring control valve with said gas springs. The invention operates to variably control with the gas spring control valve the pressure of the gas in the gas springs to thereby dynamically modulate the stiffness of the resilient gas spring in a manner to control the stroke of the resonant piston compressor within predetermined safe limits.

US Patent:

47194090, Jan 12, 1988

Filed:

Oct 2, 1985

Appl. No.:

6/782887

Inventors:

Richard A. Dorman - Troy NY

Assignee:

Mechanical Technology Incorporated - Latham NY

International Classification:

G01H 1100
G01R 2702

US Classification:

324 60CD

Abstract:

A new variable impedance type system is described for measuring a preselected physical parameter such as spacing, displacement, pressure, vibration, etc. A sensor/transducer is positioned to provide the variable impedance. The sensor/transducer is part of a self-oscillatory circuit which produces pulses having a pulse rate proportional to the physical parameter being measured.

US Patent:

43454429, Aug 24, 1982

Filed:

Jun 17, 1980

Appl. No.:

6/160306

Inventors:

Richard A. Dorman - Troy NY

Assignee:

Mechanical Technology Incorporated - Latham NY

International Classification:

F25B 1300
F04B 4906

US Classification:

62160

Abstract:

A control system for controlling the operation of a reciprocating resonant free-piston variable stroke compressor of the type driven by electrodynamic linear motors wherein the spring-mass system of the compressor which is forced into vibration by the linear motor, is arranged to have a selectively variable mechanical resonant frequency generally centered on the power line frequency of the alternating current power source used to drive the linear motor. The control system provided by this invention variably controls the opening and closing of a gas spring control valve that in turn regulates the pressure of gas filled volumes selectively connected to a manifold vented by the valve. The volumes comprise the resilient gas springs for the resonant piston compressor. For this purpose, the control system comprises an alternating current sensor for deriving a sensed output signal representative of the magnitude and phase of the alternating current supplied to the linear reciprocating motor, a reciprocating piston displacement/velocity sensor for deriving a signal representative of the reciprocating free piston velocity, and an. alpha.

US Patent:

51335271, Jul 28, 1992

Filed:

Apr 29, 1991

Appl. No.:

7/692564

Inventors:

Hsiang M. Chen - Latham NY
Paul Lewis - Scotia NY
Donald S. Wilson - Clifton Park NY
Richard A. Dorman - Wynantskill NY

Assignee:

Mechanical Technology Incorporated - Latham NY

International Classification:

F16M 1300

US Classification:

248550

Abstract:

The present invention relates to an active mount system in which a vibration sensor such as a force gauge or an accelerometer senses vibrational forces transmitted through a resilient mount by a load such as a machine. The invention further includes a digital narrow-band least mean square filter that receives a sinusoid synchronous with the rotating machinery and an error signal from the load cell and generates a corrective signal to be amplified and transmitted to the electromagnet which supplies an attenuating force to the resilient mount in response to the signal. As an alternative, a wide frequency range control can be realized by the use of a wide frequency range, high gain amplifier and multi-filter phase compensation circuitry to generate the corrective force signal which is amplified and transmitted to the electromagnet.

US Patent:

47513810, Jun 14, 1988

Filed:

Aug 13, 1986

Appl. No.:

6/896604

Inventors:

Richard A. Dorman - Troy NY

Assignee:

Mechanical Technology Incorporated - Latham NY

International Classification:

H01J 516

US Classification:

250227

Abstract:

This invention relates to a detection circuit for use in a servo controlled fiber optic sensor. A low noise signal with an amplitude proportional to the magnitude of the synchronous detection output is produced without the use of filter by a calculation of the average vale of the synchronous detector output signal driving one complete cycle of the dither signal cycle. This value is fed into sample and hold circuitry, which in turn controls the series motor.

US Patent:

42543312, Mar 3, 1981

Filed:

Jan 26, 1979

Appl. No.:

6/006654

Inventors:

Richard A. Dorman - Troy NY
Curtis D. Kissinger - Gloversville NY

Assignee:

Mechanical Technology Incorporated - Latham NY

International Classification:

G01J 132

US Classification:

250205

Abstract:

A fiber optic proximity measuring instrument for measuring dynamic changes in the gap between a probe tip and a target includes a light source, two sensors for measuring reflected light and lamp brightness, and a light conducting cable for transmitting light to the target and conducting light reflected from the target back to the reflected light sensor. The lamp intensity is set by a brightness control during setup to produce a mean level of reflected light intensity, and then is automatically regulated to maintain an equal mean intensity at the reflected light sensor despite changes in target reflectivity and cable light conductance.

Author:

Richard George Dorman

ISBN #:

0080167500