Mitutoyo Corporation

Shu Hirata

Joseph Daniel Tobiason

Akihide Kimura

Norman Laman

Toru Yaku

Akio Kawai

Tomohiro Tahara

Shun Mugikura

Tatsuhiko Mukuta

A preamplifier amplifies signals input to first and second input terminals. A first switching circuit receives first and second input signals and respectively outputs those signals to the first and second input terminals. A switched capacitor circuit samples two signals amplified by the preamplifier. An integration circuit includes a fully differential operational amplifier outputting amplifying differential signals input between third and fourth input terminals between second and first output terminals, and first and second integration capacitors. A second switching circuit switches a connection relationship between the switched capacitor circuit, and the first and second integration capacitors. A third switching circuit switches a connection relationship between the first and second integration capacitors, and third and fourth output terminals. A cycle including sampling and signal integration is performed twice, and the first to third switching circuits switch the connection relationships each time the cycle changes.

Front-end circuit and encoder

An encoder includes scale and detection head. The detection head includes light source (transmitting unit) and light-receiving unit (receiving unit). The light-receiving unit includes light-receiving surface (receiving surface) and converts light received at the light-receiving surfaceinto differential detection signals with two phases and outputs the same. The light-receiving surface includes element array group including four element arrays provided in a parallel manner along an orthogonal direction, with each element array including a plurality of light-receiving elements (receiving elements). The plurality of element arrays in the element array group are disposed at positions where the sum of: (i) a distance in the orthogonal direction from a reference position to a positive phase signal element array; and (ii) a distance in the orthogonal direction from the reference position to the negative phase signal element array, is the same for all the phases of the at least two phases.

Encoder

An optical encoder configuration comprises a scale, an illumination source, and a photodetector configuration. The illumination source is configured to output structured illumination to the scale. The scale extends along a measuring axis direction and is configured to output scale light that forms a detector fringe pattern comprising periodic high and low intensity bands that extend over a relatively longer dimension along the measuring axis direction and are relatively narrow and periodic along a detected fringe motion direction transverse to the measuring axis direction. The high and low intensity bands move along the detected fringe motion direction transverse to the measuring axis direction as the scale grating displaces along the measuring axis direction. The photodetector configuration is configured to detect a displacement of the high and low intensity bands along the detected fringe motion direction and provide respective spatial phase displacement signals that are indicative of the scale displacement.

Contamination and defect resistant optical encoder configuration including first and second illumination source diffraction gratings arranged in first and second parallel planes for providing displacement signals

Contamination and defect resistant optical encoder configuration including a normal of readhead plane at a non-zero pitch angle relative to measuring axis for providing displacement signals

Contamination and defect resistant optical encoder configuration outputting structured illumination to a scale plane for providing displacement signals

An optical encoder configuration comprises an illumination portion, a scale, and a photodetector configuration. The illumination portion transmits source light to a scale which outputs a periodic scale light pattern to the photodetector configuration. The photodetector configuration comprises a set of N spatial phase detectors arranged in a spatial phase sequence along a direction transverse to the measuring axis comprising two outer spatial phase detectors at a start and end of the sequence along the direction transverse to the measuring axis. At least a majority of the respective spatial phase detectors are relatively elongated along the measuring axis direction and relatively narrow along the direction perpendicular to the measuring axis direction, and comprise periodic scale light receptor areas positioned corresponding to a respective spatial phase of that spatial phase detector relative to the periodic scale light pattern, and are configured to provide a respective spatial phase detector signal.

Contamination and defect resistant optical encoder configuration for providing displacement signal having a plurality of spatial phase detectors arranged in a spatial phase sequence along a direction transverse to the measuring axis

There is provided an absolute position detection type photoelectric encoder which improves robustness to dirt while maintaining high resolution. A two-level code pattern according to a pseudo random code sequence is provided on a scale along a length measurement direction. Each code of the two-level code pattern indicates a code '1' or a code '0', and includes two bits. Each of the two bits is L or H. The code &#x201c;1&#x201d; is represented by an A pattern which is a combination of L and H, and the code &#x201c;0&#x201d; is represented by a B pattern which is a combination of L and L or a C pattern which is a combination of H and H. When the codes &#x201c;0&#x201d; are continued, the B pattern and the C pattern are alternately used.

Scale for an absolute position detection type photoelectric encoder with three or more two-bit combination patterns are used to represent a two-level code pattern

A scale is provided with a two-level code pattern according to a pseudo random code sequence along a length measurement direction. Each code of the two-level code pattern indicates a code '1' or '0', each code includes two bits, and each bit of the two bits is L or H. The code &#x201c;1&#x201d; is represented by an A pattern which is a combination of L and H, and the code &#x201c;0&#x201d; is represented by a B pattern which is a combination of L and L or by a C pattern which is a combination of H and H. When the codes &#x201c;0&#x201d; are continued, the B pattern and the C pattern are alternately used. The scale is commonly used in a reflective type encoder or transmissive type encoder. A detection head part includes an inversion processing unit which performs inversion processing to a detection image of the scale as required.

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Kawasaki, Japan

Shu Hirata