Abstract: Disclosed is a displacement sensor configuration, comprising a scale grating disposed in a first direction; and a scale light imaging configuration which includes first and second optical paths and a detector including first and second detector portions. The imaging portion inputs a first scale light component output by the scale grating along the first optical path and transmits the first scale light component to the first detector portion, the imaging portion inputs a second scale light component output by the scale grating along the second optical path and transmits the second scale light component to the second detector portion, the first detector portion is configured to output a first displacement signal indicative of a displacement along the first direction, and the second detector portion is configured to output a second displacement signal indicative of a displacement along a second direction perpendicular to the first direction.

Abstract: An image correlation displacement sensor is provided for measuring yaw rotation relative to a target surface using a simple configuration compatible with a fast measurement sample rate. The image correlation displacement sensor may include: an illumination portion (130) which emits illumination light to the target surface to produce a speckle field; an imaging portion (240) which captures a plurality of images including the speckle fields produced on the target surface; and a processing portion (200) which measures a displacement including a rotation about a yaw axis of the target surface in accordance with first and second region translational displacements determined based on the plurality of images captured along the first optical path and the second optical path, and a known separation between the first and second regions.

Abstract: Disclosed is a displacement sensor configuration, comprising a scale grating disposed in a first direction; and a scale light imaging configuration which includes first and second optical paths and a detector including first and second detector portions. The imaging portion inputs a first scale light component output by the scale grating along the first optical path and transmits the first scale light component to the first detector portion, the imaging portion inputs a second scale light component output by the scale grating along the second optical path and transmits the second scale light component to the second detector portion, the first detector portion is configured to output a first displacement signal indicative of a displacement along the first direction, and the second detector portion is configured to output a second displacement signal indicative of a displacement along a second direction perpendicular to the first direction.

Abstract: An image correlation displacement sensor is provided for measuring yaw rotation relative to a target surface using a simple configuration compatible with a fast measurement sample rate. The image correlation displacement sensor may include: an illumination portion (130) which emits illumination light to the target surface to produce a speckle field; an imaging portion (240) which captures a plurality of images including the speckle fields produced on the target surface; and a processing portion (200) which measures a displacement including a rotation about a yaw axis of the target surface in accordance with first and second region translational displacements determined based on the plurality of images captured along the first optical path and the second optical path, and a known separation between the first and second regions.

Abstract: A fixed wavelength absolute distance interferometer including a first interferometer comprising a first light source transmitting a first light beam having a wavelength W toward a measurement target, a wavefront radius detector configured to provide a first measurement responsive to the wavefront radius at the wavefront radius detector, and a first path length calculating portion calculating a coarse resolution absolute path length measurement R; and a second interferometer comprising a beam transmitting device transmitting a second-interferometer light beam having a wavelength ?, a beam splitting/combining device separating the second-interferometer light beam into reference and measurement beams and combining the returning reference and measurement beams into a combined beam, a second-interferometer detector configured to receive the combined beam and provide signals of a phase ? of the combined beam, and a second path length calculating portion configured to determine a medium resolution absolute path leng

Abstract: An image correlation displacement sensor for measuring a displacement component along a direction perpendicular to a target surface, with a simple configuration. The sensor may include: an illumination portion (130?) which emits illumination light; an imaging portion including at least two optical paths (A and B?) which are used to capture multiple images of a speckle field produced by the target surface (300), one of which (A) is inclined with respect to a normal to the target surface in proximity to the target surface, and an element (110?) which deflects an at least one of the optical paths (A and B?); and a processing portion (200) which measures a displacement relative to the target surface along a direction which includes a component normal to the target surface (300) in accordance with the correlation of multiple images captured in the optical paths (A) and (B?).

Abstract: A fixed wavelength absolute distance interferometer including a first interferometer comprising a first light source transmitting a first light beam having a wavelength W toward a measurement target, a wavefront radius detector configured to provide a first measurement responsive to the wavefront radius at the wavefront radius detector, and a first path length calculating portion calculating a coarse resolution absolute path length measurement R; and a second interferometer comprising a beam transmitting device transmitting a second-interferometer light beam having a wavelength ?, a beam splitting/combining device separating the second-interferometer light beam into reference and measurement beams and combining the returning reference and measurement beams into a combined beam, a second-interferometer detector configured to receive the combined beam and provide signals of a phase ? of the combined beam, and a second path length calculating portion configured to determine a medium resolution absolute path leng

Abstract: A reference mark configuration for an interferometric miniature grating encoder readhead using fiber optic receiver channels is provided. The readhead includes primary fibers that provide reference mark primary signals processed to generate a reference signal with accuracy of approximately 0.2 microns. The readhead may include secondary fibers used to generate reference mark secondary signals processed to generate a reference signal with accuracy of approximately 20 nanometers. Spatial filter masks configured for the secondary fiber optic receiver channels provide two spatially periodic secondary signals arising from interference fringes outside of the receiving area of the primary fiber optic receiver channels. The secondary signals are out of phase with one another and their spatial frequency is higher than that of the primary signals. A signal crossing of the reference mark secondary signals is identified that is spatially adjacent to a signal crossing of the reference mark primary reference signals.

Abstract: A method characterizes field of view (FOV) distortion and may correct machine vision measurements accordingly. A plurality of distorted images are acquired, with the same calibration target at a plurality of spaced-apart locations within the FOV. The method analyzes the images and determines distortion parameters that can correct the distortions in the images such that features included in the calibration target pattern achieve a sufficient or optimum degree of congruence between the various images. Distortion parameters may be determined for each optical configuration (e.g., lens combination, magnification, etc.) that is used by a machine vision inspection system. The distortion parameters may then be used to correct FOV distortion errors in subsequent inspection and measurement operations.

Abstract: A photoelectric encoder has a telecentric optical system in which a first lens and an aperture located at a focal position of the first lens are interposed between a main scale and a photoreceptor. At least a second lens is interposed between the aperture and the photoreceptor with a focus of the second lens on the aperture, thereby constituting a bilateral telecentric optical system. This makes it possible to improve the signal detection efficiency and increase the assembly tolerance.

Abstract: A reference mark configuration for an interferometric miniature grating encoder readhead using fiber optic receiver channels is provided. The readhead includes “primary” fibers that provide reference mark primary signals processed to generate a reference signal with accuracy of approximately 0.2 microns. The readhead may include “secondary” fibers used to generate reference mark secondary signals processed to generate a reference signal with accuracy of approximately 20 nanometers. Spatial filter masks configured for the secondary fiber optic receiver channels provide two spatially periodic secondary signals arising from interference fringes outside of the receiving area of the primary fiber optic receiver channels. The secondary signals are out of phase with one another and their spatial frequency is higher than that of the primary signals. A signal crossing of the reference mark secondary signals is identified that is spatially adjacent to a signal crossing of the reference mark primary reference signals.

Abstract: A fiber optic readhead and scale arrangement for measuring displacement provides a reference position indication. The scale includes a scale track comprising a first type of track portion providing first level of zero order reflectance, such as a grating, and a reference mark providing a second level of zero order reflectance, such as a mirror. The reference mark is configured with certain length or boundary spacing dimensions determined based on certain fiber optic receiver channel aperture dimensions in the readhead. In some configurations a fiber optic readhead and track that provides the reference position indication is separate from a fiber optic readhead and track that provides periodic incremental measurement signals. In some configurations an integrated fiber optic readhead and an integrated track structure provide both the reference position indication and the periodic incremental measurement signals.

Abstract: An adaptive light-path surface tilt sensing configuration is provided that identifies when a ray bundle is projected along a direction normal to a workpiece surface. As a result, the tilt of the workpiece surface may be determined. The surface tilt sensor may comprise an illumination and detector portion and an objective lens. The illumination and detector portion may comprise a light source, a collimating lens, a beamsplitter, a controllable ray bundle position control portion, and a photodetector configuration. These elements are configured to provide a ray bundle alignment sensing arrangement that provides a signal indicating when a projected ray bundle and a reflected ray bundle have the best degree of alignment, in addition to other functions. The best degree of alignment corresponds to a ray bundle that is projected along the direction normal to the workpiece surface provides.

Abstract: An adaptive light-path surface tilt sensing configuration is provided that identifies when a ray bundle is projected along a direction normal to a workpiece surface. As a result, the tilt of the workpiece surface may be determined. The surface tilt sensor may comprise an illumination and detector portion and an objective lens. The illumination and detector portion may comprise a light source, a collimating lens, a beamsplitter, a controllable ray bundle position control portion, and a photodetector configuration. These elements are configured to provide a ray bundle alignment sensing arrangement that provides a signal indicating when a projected ray bundle and a reflected ray bundle have the best degree of alignment, in addition to other functions. The best degree of alignment corresponds to a ray bundle that is projected along the direction normal to the workpiece surface provides.

Abstract: A hand-size structured-light three-dimensional metrology imaging system and method. Laser illumination stripes are scanned across a workpiece surface for obtaining z-height and x-coordinate information. A Scheimpflug configuration is used. Utilizing this configuration, a laser illumination stripe across a raised workpiece portion will be shown in a contour image at the image sensor in a focused manner, such that the offsets along the contour image line due to the raised portions of the workpiece surface can be accurately converted to a z-height measurement. The y-axis positions associated with each of the contour images, used for reassembling the information from the contour images into a surface map for the workpiece, may be determined without the need for a position sensor, by including a reference object in the contour images.

Abstract: A position sensor using a novel structured light generating scale or target member is provided. An imaging array is capable of measuring the relative translation and orientation of the structured light generating scale or target member in X, Y, Z, yaw, pitch, and roll (“6D”) simultaneously, and with high precision. The target member includes an array of lenses that provide an array of structured light patterns that diverge, converge, or both, to change the size of the corresponding structured light image as a function of the “Z” coordinate of the relative position, in various embodiments. The X-Y position of each individual structured light image on the imaging array varies with the relative X-Y position of the structured light generating target member, and the shape of structured light image changes as a function of the relative angular orientation.

Abstract: A method for connecting optical signals carried by optical fibers between an optical encoder readhead and an optical signal processing IC having a plurality of photodetector portions arranged in a photodetector configuration. The optical signal processing IC is fixed to a substrate at a first position and orientation. Then, a reference-surface block including at least one reference surface is fixed to the substrate in a second orientation and position based on the first position and orientation. A fiber-optic end piece is provided, which has at least one corresponding-reference surface and a plurality of optical fiber locating features that are arranged relative to the corresponding-reference surface. A plurality of the optical fibers are fixed to the plurality of optical fiber locating features to provide a coupling configuration of optical fiber ends that nominally matches the photodetector configuration.

Abstract: A displacement measuring device including a scale, and an optical readhead including an index pattern and a light receiving element is provided. A bright/dark pattern arising from a scale grating is detected by the readhead to measure displacement. In various embodiments, a magnification of the pattern is adjusted by the spacing between at least a lens element, aperture element, and detection plane of the readhead. An aperture can be designed to provide a diffraction-limited telecentric imaging configuration that filters an image of the scale grating to provide a sinusoidal intensity pattern that supports highly interpolated measurements. An aperture dimension, selected in relation to the grating pitch and other parameters, can provide a desirable combination of readhead operating characteristics including one or more of a desired depth of field; degree of spatial filtering; and optical signal power.

Abstract: A position sensor using a novel optical path array (OPA) element, an angle-selective spatial filter, and an imaging array is capable of measuring the translation and orientation relative to a target member in X, Y, Z, yaw, pitch, and roll (“6D”) simultaneously, and with high precision. A target member includes an array of target points surrounded by a contrasting surface. The position sensor uses the OPA element in combination with the angle-selective spatial filter in a target point imaging arrangement such that the imaging array of the position sensor only receives light rays that enter the OPA element according to an operable cone angle ?. Accordingly, each target point generally produces a ring-shaped image having a size on the imaging array that varies with the Z position of each target point. The X-Y position of each target point image on the imaging array varies with the X-Y position of each target point.

Abstract: A displacement measuring device including a scale, and an optical readhead including an index pattern and a light receiving element is provided. A bright/dark pattern arising from a scale grating is detected by the readhead to measure displacement. In various embodiments, a magnification of the pattern is adjusted by the spacing between at least a lens element, aperture element, and detection plane of the readhead. An aperture can be designed to provide a diffraction-limited telecentric imaging configuration that filters an image of the scale grating to provide a sinusoidal intensity pattern that supports highly interpolated measurements. An aperture dimension, selected in relation to the grating pitch and other parameters, can provide a desirable combination of readhead operating characteristics including one or more of a desired depth of field; degree of spatial filtering; and optical signal power.