Mitutoyo Corporation

Michelle Mary Milvich

Joseph Daniel Tobiason

Vidya Venkatachalam

Michael Nahum

David William Sesko

Benjamin K Jones

Daniel John Kapner

Michael M Nahum

An encoder configuration comprises an illumination portion, a scale comprising a scale track, and a signal processing electronics. The signal processing electronics may include a detector comprising a first set of three detector sub-portions that provide a first set of signals comprising three respective sub-portion signal subsets that have nominally the same signal characteristics when the scale track is not contaminated or defective. The processing electronics analyze the first set of signals and identify a least-similar sub-portion signal subset that has a corresponding signal characteristic value that is least similar to comparable signal characteristic values associated with more-similar sub-portion signal subsets of the first set of signals. Position measurements are based on valid signals including a plurality of the more-similar sub-portion signal subsets and not including the least-similar sub-portion signal subset if it is significantly different. Accurate measurement may be provided despite significant scale contamination or defects.

Optical encoder having contamination and defect resistant signal processing

An encoder configuration comprises a dual-modulation scale track pattern that provides a first intensity modulation component for producing periodic signals, and a second intensity modulation component for producing a long-range absolute signal. The dual-modulation scale track pattern increases the range-to-resolution ratio of the encoder without the use of additional scale tracks that would increase the width of the encoder components. The long-range signal may be encoded in the dual-modulation scale track pattern either by varying certain dimensions of pattern elements included in the scale track or by superimposing a layer including an optical density variation along on the track on pattern elements of similar areas. In either case, the net offset and/or amplitude levels of the associated signals are modified along the scale track. These modified offset and/or amplitude levels provide the basis for the long-range absolute signal.

Absolute optical encoder with long range intensity modulation on scale

An encoder configuration comprises an illumination portion, absolute scale pattern comprising absolute tracks, and a detector having a width dimension YDETABS. An absolute track pattern comprises geometrically congruent sub tracks, and the congruent sub tracks are arranged such that if one is translated by the width dimension YDETABS, then they will nominally coincide. The congruent sub tracks may be separated by a dimension YCENT that is less than YDETABS, and may each have a dimension YTOL, such that [YCENT+2(YTOL)] is greater than YDETABS. Thus, the detector may be narrower than the absolute track pattern, but because the detector edges are each nominally located over congruent sub tracks the detected signal is not sensitive to lateral misalignment of the detector within the pattern. These principles provide great freedom in configuring advantageous individual pattern features in the absolute track, even though the detector is narrower than the absolute track.

Scale track configuration for absolute optical encoder including a detector electronics with plurality of track detector portions

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

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. Accordingly, three or more structured light images analyzed in the same image are usable to determine a 6D measurement between the structured light generating target member and the array detector. X and Y displacement of the target member can be accumulated by known methods and the other 6D measurement components are absolute measurements at any position.

Scale for use with a translation and orientation sensing system

An induced current position transducer reduces spatial phase errors associated with layout constraints. Each winding of the transducer comprises a set of loops arranged in hypothetical basic polarity zones that alternate along the measuring axis and a set of loops arranged in hypothetical offset polarity zones that are offset from the basic polarity zones along the measuring axis. Hypothetical offset zones are defined at positions where basic and offset polarity zones that have opposite polarities overlap. Due to layout constraints, each winding may have an offset zone including an unbalancing coupling area that differs from the coupling area in the majority of offset zones. The windings are configured such that the amount of unbalanced coupling area included in the offset zones of each respective winding is approximately the same for each of the windings, making their respective phase errors approximately the same.

Compact pitch-compensated inductive displacement transducer

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 &#x3b1;. 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. Accordingly, three or more target point images analyzed in the same image are usable to determine a 6D measurement relative to the target member. X and Y displacement of the target member can be accumulated by known methods and the other 6D measurement components are absolute measurements at any position.

Optical path array and angular filter for translation and orientation sensing

A scale loop formed by a loop trace of electrically conductive material is usable in an induced current position transducer. The scale loop is continuous and has a particular shape depending on the configuration of the induced current position transducer. The scale loop is not in contact with other highly conductive materials. The dimensions of the cross-section of the conducting trace are chosen to increase the transfer of energy through the transducer.

Induced current position transducers having improved scale loop structures

A reduced-offset induced current position transducer uses a tape scale to inductively couple at least one transmitter winding on a read head to one or more receiver windings on the read head. The at least one transmitter winding generates a primary magnetic field coupled to the tape scale. Apertures in the tape scale determine a pattern of induced current flow in the tape scale, including induced current flow in a region away from the primary magnetic field. At least one receiver winding is inductively coupled to the tape scale in a region away from the primary magnetic field. At least one of the transmitter winding or the receiver windings is formed in a periodic pattern complementary to the configuration of the apertures on the tape scale. Depending on the relative position between the read head and the scale, the receiver windings inductively couple to the tape scale to various degrees. A compact, high accuracy, high resolution inductive position sensor using an economical tape scale results. Low power operation is possible.

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Seattle, WA, United States of America

Michelle Mary Milvich