Mitutoyo Corporation

Fujitsu Corporation

Jatco Corporation

Tektronix, Inc.

Yoshiaki Kato

Yoshifumi Kajiwara

Hiroaki Matsuda

Hiroaki Sakashita

Manabu Hongo

Hidekatsu Kobayashi

Tatsuhito Araki

Hidehiko Hizuka

Wataru Murata

Toshiyuki Itoh

Nariyasu Hayakawa

Toshikazu Ishioka

Masamichi Watanabe

Hiroshi Kobayashi

Toru Yaku

Shigeru Yamaguchi

Miyako Mizutani

Kazuhiro Kakuguchi

Atsuko Yamamoto

The photoelectric rotary encoder includes: a generally disk-shaped scale with a grating-like pattern formed with a predetermined period along a measurement direction, the measurement direction being a direction of rotation of a measurement target that rotates on a predetermined axis, the scale being plate-like and centered on an axis of rotation; and a head that detect, from the scale, the amount of displacement caused by the rotation of the measurement target. The head includes a light source, a diffraction unit with grating parts, and a light-receiving unit with light-receiving elements. The grating parts of the diffraction unit are formed as deformed grating parts that spread cut wide, from the center on the axis of rotation, along the grating-like pattern of the scale. The light-receiving elements are formed as linear grating parts.

Photoelectric rotary encoder

A scale capable of maintaining measurement accuracy even if the pattern of the scale pattern is scratched is provided. The scalecomprises a scale patternhaving a plurality of unit patterns provided at a predetermined pitch along the measurement direction on a surface thereof. At least one of the plurality of unit patterns comprises a plurality of loop portionsformed with conductors in a loop shape. The plurality of loop portionsincluded in the unit pattern are arranged so as to be spaced from each other such that the centers of gravity of the loop portionsare at the same position in the measurement direction on the surface of the scale. Thereby, the plurality of loop portionsincluded in the unit pattern can prevent deviation of the center of gravity of the magnetic flux distribution in the measurement direction, even if any of the plurality of the loop portionsis scratched. Therefore, the scalecan maintain the measurement accuracy.

Scale used in an electromagnetic inductive encoder or a magnetic encoder

An optical encoder includes a scale, a calculator, and a head having a light source, an image capturer, and a lens array having first and second lenses. The calculator includes a signal generator, an extractor, a signal combiner, and a displacement calculator. The signal generator generates a sine wave signal. The extractor extracts first and second regions. The signal combiner, based on an inter-regional distance, uses a sine wave signal of the second region to generate a sine wave signal that extends to a first end of the first region such that the generated sine wave signal overlaps with a sine wave signal of the first region. The signal combiner also combines the sine wave signal of the first region with the generated sine wave signal. The displacement calculator calculates an amount of relative displacement based on the sine wave signal that is combined by the signal combiner.

Optical encoder and calculation method for calculating relative displacement between an encoder scale and an encoder head facing the scale

Scale pattern in a scale of an optical encoder includes a first scale mark that blocks a first light from being guided to an image capturer and guides a second light to the image capturer, and a second scale mark that guides the first light and the second light to the image capturer. Second scale mark is arranged in an ABS pattern and the first scale mark is arranged in an INC pattern by incorporating the second scale mark. Image capturer includes a first image capturing section that captures an image of the ABS pattern from the first light that arrives via the second scale mark, and a second image capturing section that captures an image of the INC pattern from the second light that arrives via the first scale mark and the second scale mark. Calculator calculates a position of a head relative to the scale.

Optical encoder using two different wavelengths to determine an absolute and incremental output for calculating a position

There is provided a signal processing method, for a photoelectric encoder, capable of correctly determining a bright part and a dark part of a bright/dark pattern having distorted light intensity distribution by setting an appropriate threshold. A detector unit includes a light source, a light-receiving detector that receives transmitted light from a scale to acquire a bright/dark image, and a lens arranged between the light source and the light-receiving detector. The detector unit classifies the bright/dark image acquired by the light-receiving detector into an image-forming region corresponding to a center region of the lens and a non-image-forming region corresponding to a region except for the center region of the lens, calculates a representative value reflecting a light intensity of the image-forming region, and obtains a pre-processed bright/dark image in which the light intensity of the non-image-forming region is replaced with the representative value.

Signal processing method for photoelectric encoder

There is provided an electromagnetic inductive encoder that allows reduction in the number of tracks on a scale for reduction in the size of the scale. The electromagnetic inductive encoder includes a scale having a scale pattern, a head, and computation unit. The head includes transmission unit, which includes transmission coils, and reception unit, which includes reception coils. The scale pattern has a first pattern, which causes the reception coils to receive positive current, and a second pattern, which causes the reception coils to receive negative current. The computation unit includes a determination unit, which, when the positive current is detected, determines that the current is associated with the first pattern, and, when the negative current is detected, determines that the current is associated with the second pattern, a signal generation unit, which generates a signal formed of '1' representing the first pattern and '0' representing the second pattern based on the result of the determination, and a position calculation unit, which calculates the position of the head based on the signal generated by the signal generation unit.

Electromagnetic inductive encoder

A head provided to a shape measuring apparatus includes a translucent stylus head that displaces integrally with a light source and a photoreceiver, and is arranged between the light source and the photoreceiver. The stylus head includes an incident portion that causes the light from the light source to be incident on an interior of the stylus head, a reflection portion that totally reflects the incident light, and a light emission portion that emits the light that is totally reflected toward the photoreceiver. Evanescent light is generated at the measurement surface by the light that is totally reflected by the total reflection surface. The stylus head brings the measurement surface and a surface of a measurable object to face each other, separates the measurement surface from the surface of the measurable object, and is arranged such that the evanescent light reaches the surface of the measurable object.

Shape measuring apparatus

An encoder includes a scale having graduations arranged in a measurement direction, a head including a light receiving unit configured to receive, via the scale, light emitted from a light source, and being configured to detect a relative movement amount with respect to the scale by relatively moving in the measurement direction of the scale, and a control unit configured to control the head. The control unit includes a light amount control unit configured to perform control so as to keep a predetermined light receiving amount by increasing or decreasing a light amount of the light source, an error determination unit configured to determine an error based on light received by the light receiving unit, and a light amount suppression unit configured to suppress a light amount of the light source by stopping control performed by the light amount control unit, when the error determination unit determines as an error.

Photoelectric encoder

A scale includes a scale grating formed with a period P. A light source grating includes a grating formed with a period 2P, the light source grating being disposed between a light source and the scale. Interference fringe detection means is configured to be able to detect a bright part of an interference fringe with the period P, the interference fringe being generated by the light source grating and the scale. The interference fringe detection means detects a first interference fringe formed by light coming from the scale and a second interference fringe formed by light coming from the scale, a position of a bright part of the second interference fringe being shifted from a position of a bright part of the first interference fringe by a half of the period P (i.e., P/2).

Optical encoder

The photoelectric encoderincludes a scale, and a detection headincluding a light emitting unit, an index, and a detection unit. The indexincludes a first index portionconsisting of diffraction portions and non-diffraction portions alternately juxtaposed at a predetermined pitch along the longitudinal direction of the scale, and a second index portionconsisting of diffraction portions and non-diffraction portions alternately juxtaposed at twice the pitch of the first index portion. The scaleis configured to include a first pattern portionconsisting of diffraction portions and non-diffraction portions alternately juxtaposed at a predetermined pitch along the longitudinal direction of the scale, and a second pattern portionconsisting of diffraction portions and non-diffraction portions arranged in a checkered pattern.

An optical encoder includes an origin point detection scale having an origin point detection pattern and an inverse origin point detection pattern that is the inverse of the origin point detection pattern; a light source emitting light at the origin point detection scale; a light source grid that is inserted on the light source side of the origin point detection scale, the light source grid having two first light source grid patterns corresponding to the origin point detection pattern and the inverse origin point detection pattern, respectively; a photoreceiver detecting a signal from light that has passed through the origin point detection scale; and a photoreceiver grid inserted on the photoreceiver side of the origin point detection scale, the photoreceiver grid having two first photoreceiver grid patterns that are a pattern either identical to or the inverse of the first light source grid pattern.

Optical encoder comprising an origin point detection scale having an origin point detection pattern

In a scale, a reference detection pattern and a displacement detection pattern are formed. A detection head outputs a reference detection signal, a phase compensation signal, and a displacement detection signal. A signal processing unit generates a reference signal by amplifying one or both of the phase compensation signal and the reference detection signal and adding up them, and detects a position of the detection head relative to the scale. A combined light receiving grating includes a reference detection light receiving grating and a phase compensation light receiving grating disposed so as to be shifted from the reference detection light receiving grating in the measurement direction. A combined light receiving element includes a reference detection light receiving element configured to output the reference detection signal and a phase compensation light receiving element configured to output the phase compensation signal.

Encoder having a detection head with a reference detection receiving grating and a phase compensation receiving grating

A scale and an optical encoder capable of maintaining an accuracy of a reference position irrespective of an error in attaching a detection head are provided. The scale according to the present invention is a scale including main-signal scale gratings having grating patterns of a predetermined pitch, and a reference-signal pattern, in which the main-signal scale gratings are arranged in parallel in a direction perpendicular to a length measurement axis of the main-signal scale gratings and are different from each other in phase by &#xbd;, and the reference-signal pattern is formed on the length measurement axis of the main-signal scale gratings. The optical encoder according to the present invention includes a light source, main-signal light source gratings, reference-signal light source gratings, main-signal receiver gratings, and a reference-signal receiver element.

Scale and optical encoder

An optical encoder according to the present invention includes a light source that emits light; a scale including scale gratings each having a predetermined pitch; a light source grating disposed between the light source and the scale and having a predetermined pitch; and an interference fringe detector that detects an interference fringe generated by the light source grating and the scale. The scale gratings are disposed side by side, and the adjacent scale gratings are displaced from each other by a &#xbd; period.

A photoelectric encoder includes an absolute scale provided with an absolute pattern based on pseudo-random data, and a detection head including a light source that emits light to the absolute pattern of the absolute scale, and a light receiving unit that receives light from the absolute pattern, and it detects an absolute position of the detection head with respect to the absolute scale. In the photoelectric encoder, the absolute pattern is composed of a grating part and a dark part arranged in a repetitive manner. The photoelectric encoder further includes an interference pattern generation means that generates an interference pattern in combination with the grating part, and an interference pattern signal processing unit that detects the pseudo-random data of the absolute pattern based on the interference pattern received by the light receiving unit.

Photoelectric encoder having an interference pattern signal processing unit detects the pseudo-random data of the absolute pattern of an absolute scale

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Kawasaki, Japan

Yoshiaki Kato