Geert J Wijntjes

6718143, Apr 6, 2004

May 13, 2002

10/144585

Geert Johannes Wijntjes - Chelsea MA

Visidyne, Inc. - Burlington MA

H04B 1006

398202, 398188, 398212

An improved system and method of decoding a phase modulated encoding of a pair of optical beams is preferably achieved by generating a plurality of optical fringes from the pair of optical beams, sampling each optical fringe and generating a set of at least three phase offset signals from each sampled optical fringe, each generated signal having a unique and known phase difference relative to each sampled optical fringe, and by deriving a quantitative representation of the phase encoding of the pair optical beams from information provided from each set of generated signals. Optionally, the quantitative representation is converted into an electric signal.

20030095257, May 22, 2003

Nov 6, 2002

10/288875

Geert Wijntjes - Chelsea MA, US
Constantine Markos - Lynn MA, US

G01J004/00

356/364000

An optically coupled rotary encoder that is capable of measuring and encoding the angle of rotation of a rotating or stationary object. A polarizer rotates synchronously with the rotatable object and inputs broadband or single frequency unpolarized light. The polarizer outputs and directs polarized light towards a plurality of fixed analyzers and light detectors. Each fixed analyzer outputs and directs further polarized light towards one of the light detectors. Each light detector outputs an electrical signal to a phase processor based upon one attribute of the further polarized light. The phase processor outputs a phase angle with high resolution ( 10 bit) with high accuracy and frequency (5 Mhz). The system and method can operate in harsh environments having high temperatures, dirt and debris and is not susceptible to EMI/RFI.

20050002032, Jan 6, 2005

May 5, 2004

10/839073

Geert Wijntjes - Chelsea MA, US
Constantine Markos - Lynn MA, US

G01D005/34
G01J004/00

356364000, 250231160, 250225000

An optically coupled rotary encoder that is capable of measuring and encoding the angle of rotation of a rotating or stationary object. A polarizer rotates synchronously with the rotatable object and inputs broadband or single frequency unpolarized light. The polarizer outputs and directs polarized light towards a plurality of fixed analyzers and light detectors. Each fixed analyzer outputs and directs further polarized light towards one of the light detectors. Each light detector outputs an electrical signal to a phase processor based upon one attribute of the further polarized light. The phase processor outputs a phase angle with high resolution (>12 bit) with high accuracy and frequency (5 MHz). The system and method can operate in harsh environments having high temperatures, dirt and debris and is not susceptible to EMI/RFI.

46726187, Jun 9, 1987

Jul 9, 1986

6/884872

Geert Wijntjes - Belmont MA
Michael Hercher - Marblehead MA

Beckman Instruments, Inc. - Fullerton CA

H01S 313

372 32

A method and means for stabilizing the difference in frequencies between the frequency components of a two frequency laser beam influenced by Zeeman effect frequency splitting, accurately determines the frequency separation independently of the individual frequencies or intensities of either of the frequency components. Frequency stabilization is accomplished by mechanical and thermal adjustments to the lasing chamber length of the laser by a closed loop servo control referencing the frequency difference between laser beam components and a reference signal having a frequency equal to the desired frequency difference.

46555870, Apr 7, 1987

Sep 25, 1985

6/781185

Geert Wijntjes - Belmont MA
Michael Hercher - Marblehead MA

Beckman Instruments, Inc. - Fullerton CA

G01J 345
G01B 902

356346

An improved mirror scan control for driving a movable mirror in an interferometer with a constant scan velocity comprises a closed loop servo control which provides constant velocity mirror scan in response to a phase comparison of a signal derived from the beat frequency of a two frequency laser beam passing through the interferometer and a selected frequency reference signal, wherein the difference in frequencies or beat frequency of the two frequency laser beam is stabilized at a specified difference in frequencies. The mirror scan control employs a phase lock control loop which locks the frequency of the referenced signal with the frequency of the signal derived from the laser beam to provide precise mirror velocity control.

47115734, Dec 8, 1987

Dec 12, 1986

6/940196

Geert Wijntjes - Belmont MA
Michael Hercher - Marblehead MA

Beckman Instruments, Inc. - Fullerton CA

G01J 345

356346

An improved mirror alignment control for dynamically aligning the reflecting mirrors bounding the optical path in an interferometer comprises a closed loop servo control which utilizes a two frequency laser beam to provide phase comparison between beams traversing differing portions of the optical paths in the interferometer to determine alignment of the mirrors, said phase comparison providing a correction signal to direct multi-axial alignment of at least one of the mirrors.

50981900, Mar 24, 1992

Aug 7, 1989

7/390192

Geert J. Wijntjes - Chelsea MA
Michael Hercher - Marblehead MA

Optra, Inc. - Beverly MA

G01B 902

356356

A metrology system includes means for generating an interference fringe pattern as a function of a parameter to be measured, transducer apparatus for simultaneously generating three intensity-modulated optical signals, I. sub. R, I. sub. S and I. sub. T, that are related to the interference fringe pattern; signal processing apparatus for accurately determining an aspect of the interference fringe pattern from the three signals; means for accumulating phase information proportional to the aspect of the interference fringe pattern; and means for converting the accumulated phase and aspect information to desired outputs indicative of the parameter to be measured.