Mitutoyo Corporation

Synrad, Inc.

Speed Control, Inc.

Benjamin K Jones

Michael Nahum

Andrew Patzwald

David William Sesko

Scott Allen Harsila

Jason W Bethel

Jeffery A Broderick

Karl Gustav Masreliez

Eugene F Yelden

Joseph Daniel Tobiason

Kim W Atherton

Avron Zwilling

Robert Kamil Bryll

Casey Edward Emtman

Vidya Venkatachalam

Yong Xie

Michelle Mary Milvich

Ned D Mills

Patrick A Renalds

Stephen Gareth Alexander Smele

Jason Stuart Hartman

Erik R Stockinger

Bernadette T Baqui

Michael M Nahum

Avron M Zwilling

An interchangeable chromatic range sensor (CRS) probe for a coordinate measuring machine (CMM). The CRS probe is capable of being automatically connected to a CMM under program control. In one embodiment, in order to make the CRS probe compatible with a standard CMM auto exchange joint, all CRS measurement light transmitting and receiving elements (e.g., the light source, wavelength detector, optical pen, etc.) are included in the CRS probe assembly. The CRS probe assembly also includes an auto exchange joint element that is attachable through a standard auto exchange joint connection to a CMM. In one embodiment, in order to provide the required signals through the limited number of connections of the standard CMM auto exchange joint (e.g., 13 pins), a low voltage differential signaling (LVDS) serializer may be utilized for providing additional control and data signals on two signal lines.

Interchangeable chromatic range sensor probe for a coordinate measuring machine

A micrometer drive configuration for a handheld micrometer comprises: a frame; a spindle; a linear displacement sensor that senses a displacement of the spindle; a threaded spindle drive having a relatively coarse thread pitch, wherein the threaded spindle drive is attached to a spindle drive gear; a planetary drive gear that mates to the spindle drive gear; a ring gear surrounding and mating to the planetary drive gear; and a thimble generally surrounding the spindle drive gear, the planetary drive gear, and the ring gear. The thimble is coupled to drive the spindle drive gear through the planetary drive gear, and the planetary drive gear is sized and mounted such that the spindle drive gear turns faster than the thimble.

Fast rotary drive for a handheld micrometer

An optical pen for use in a chromatic range sensor (CRS) may be used in a probe system for a coordinate measuring machine (CMM). The optical pen includes a confocal optical path, an interchangeable optics element, an optical pen base member, and a repeatable fast exchange mount. The confocal optical path includes a confocal aperture and a chromatically dispersive optics portion. The interchangeable optics element includes the chromatically dispersive optics portion. The optical pen base member includes an external mounting surface for mounting to an external reference frame. The repeatable fast exchange mount includes a first mating half located on the base member and a second mating half located on the interchangeable optics element. The repeatable fast exchange mount is configured to allow the base member to receive and hold the interchangeable optics element in a fixed relationship relative to the base member and the external reference frame.

Interchangeable optics configuration for a chromatic range sensor optical pen

A chromatically dispersive lens configuration including thermal compensation may be utilized in chromatic confocal point sensor optical pens for chromatic range sensing. The lens configuration may include a negative power doublet lens and a positive power lens portion. The positive power lens portion comprises at least two lens elements which compensate for the overall thermal sensitivity of a chromatic confocal point sensor optical pen. The lens elements of the positive power lens portion which compensate for thermal sensitivity have an average coefficient of thermal defocus which is in a range that is at lowest 10 ppm per 10&#xb0; C. The lens configuration can be implemented with dimensions which fit a standard commercial chromatic confocal point sensor optical pen, while maintaining a level of optical performance sufficient for chromatic range sensing.

Lens configuration for a thermally compensated chromatic confocal point sensor

A correlation function peak finding method for an image correlation displacement sensing system is provided. The method may include capturing a reference image and a displaced image, and searching for an initial peak correlation function value point (CFVP) with pixel-level resolution based on correlating the reference image and displaced images at a plurality of offset positions. Then a complete set of CFVPs may be determined at each offset position in an analysis region surrounding the initial peak CFVP. Then a preliminary correlation function peak location is estimated with sub-pixel resolution, based on CFVPs included in the analysis region. Finally, curve-fitting operations are performed to estimate a final correlation function peak location with sub-pixel accuracy, wherein the curve-fitting operations apply a windowing function and/or a set of weighting factors that is/are located with sub-pixel resolution based on the preliminary sub-pixel correlation function peak location.

Correlation peak finding method for image correlation displacement sensing

A displacement measurement device has a detector area which is larger than the area of the beam spot reflected from the measurement surface. The detector area is made larger than the size of the beam spot on the detector area, in order to accommodate shifts in the location of the beam spot due to changes in the precise locations of the components of the displacement measurement device. The subset of pixels in the detector area having advantageous correlation characteristics, is then selected to perform the correlation calculation, thereby reducing data processing time requirements.

Displacement transducer with selectable detector area

A method of determining an amount of tilt may include projecting at least two coherent wavefronts toward a target surface, the wavefronts reflecting from the target surface to create an interference fringe pattern on a detector, and transmitting a beam toward the target surface, the transmitted beam reflecting from the target surface to form a beam spot on the detector. A fringe pitch indicative of a distance to the target surface may be determined based on the interference fringe pattern. A displacement on the detector of the beam spot, relative to a nominal location of the beam spot when the target surface is at a nominal angle of incidence relative to the beam, may be determined. The amount of tilt of the target surface relative to the nominal angle of incidence, may be determined based on the displacement of the beam spot and the determined fringe pitch.

Systems and methods for tilt and range measurement

An operator interface apparatus and associated methods may allow an operator to select and verify various operating parameters for an image correlation type of displacement transducer. A subset of pixels from a detector array or camera may be defined to participate in an image correlation displacement measurement operations.

Operator interface apparatus and method for displacement transducer with selectable detector area

A system and method for improving the accuracy of a speckle-based image correlation displacement sensor provides ultra-high accuracy by ensuring that, in the absence of motion, the speckle image does not vary over time. In one embodiment, the speckle image is stabilized by reducing or compensating for laser diode wavelength changes. Various methods for stabilizing the wavelength include thermoelectric temperature control, measuring and correcting the wavelength by any suitable means, or providing a specific wavelength of light feedback from an external grating. Image stabilization may also be accomplished by monitoring the warm-up process of the system. Once the system is determined to have completed the warm-up process, an indicator is provided to the user to indicate that the system is ready for use. Sensor geometric configurations that reduce or eliminate wavelength-related errors are also disclosed.

System and method for improving accuracy in a speckle-based image correlation displacement sensor

A position error correcting, or reducing, method and system used in an image-correlation system which obtains an error function generally reflecting an error occurring over a nominal reference image update length and an error occurring at a first frequency and various other system errors. The error can be compared to a first reference to fit the position error. In various embodiments, parameters of an error function can be varied in fitting the error function to the first reference. The obtained error function can then be used to determine the position error and render more accurate the image correlation system. In one exemplary implementation, the first frequency is related to a pixel pitch and the nominal reference image update length related to the distance between reference image changes is the maximum usable reference image update length.

Systems and methods for reducing position errors in image correlation systems during intra-reference-image displacements

An absolute 2D position-sensing device is usable to measure the position of a first element with respect to a second element. A 2D absolute scale includes an integrated 2D absolute scale pattern extending over the 2D scale area along each measuring axis of the scale. The integrated 2D absolute scale pattern includes a predetermined quasi-random pattern repeatedly interleaved with a plurality of code portions along each axis. Each code portion includes a plurality of code elements indicative of an absolute measurement value. The offset of the quasi-random pattern relative to a readhead of the device is combined with the absolute measurement value to determine an absolute position to a very high resolution over a relatively large 2D range.

Systems and methods for absolute positioning using repeated quasi-random pattern

An absolute 2D position-sensing device is usable to measure the relative position of two elements. A 2D absolute scale includes an integrated 2D absolute scale pattern extending over the 2D scale area along each measuring axis of the scale. The integrated 2D absolute scale pattern includes a plurality of periodic portions interleaved with a plurality of non-periodic portions along each axis. Each periodic portion includes a plurality of periodically-placed scale elements. Each non-periodic portion includes a plurality of code elements indicative of an absolute measurement value. The code elements may have a length that is narrower along each measuring axis is than the length of the periodic scale elements along each measuring axis. The offset of the periodically-placed elements relative to a readhead of the device is combined with the absolute measurement value to determine an absolute position.

Two-dimensional scale structures and method usable in an absolute position transducer

An optical displacement sensing device is provided for determining the relative displacement of a diffraction scale grating that may have a grating pitch less than the wavelength of the light of the sensing device. The sensing device includes a split light beam input portion for inputting two split light beams along respective light paths, and light beam directing elements for directing the two split beams along converging light paths toward a first zone on the scale grating to give rise to two diffracted beams along light paths which diverge. The sensing device further includes retroreflector elements for receiving the two diverging diffracted beams and retroreflecting them along light paths which converge toward a second zone on the scale grating to give rise to two later-diffracted light beams that are then directed to a shared zone. The retroreflectors may be positioned to eliminate cross-over beams and the need for polarizers. An optical detector detects at least one illumination characteristic arising from the shared zone, thus sensing displacement of the scale grating along the measuring axis.

Optical displacement sensing device with reduced sensitivity to misalignment

An absolute position-sensing device is usable to measure the relative position of two elements. An absolute scale includes an integrated track extending along a measuring axis of the scale. The integrated track includes a plurality of periodic portions interleaved with a plurality of non-periodic portions. Each periodic portion includes a plurality of periodically-placed scale elements. Each non-periodic portion includes a plurality of code elements indicative of an absolute measurement value. The code elements may have a length that is narrower along the measuring axis than the length of the periodic scale elements. The offset of the periodic-placed elements relative to a readhead of the device is combined with the absolute measurement value to determine an absolute position.

Growing community of inventors

Seattle, WA, United States of America

Benjamin K Jones