Mitutoyo Corporation

Hiroaki Kawada

Hiroatsu Mori

Yasuo Yamaguchi

Toru Yaku

Kenichi Hayashi

Seiji Sakagami

Kimitoshi Ono

Shingo Kuroki

Yuichi Ichikawa

Masashi Tsuboi

Hiroshi Yamashiro

Masaki Tomiya

Toshiharu Ozeki

Tsuyoshi Kuroiwa

A photoelectric encoder includes an irradiation unit configured to apply first and second irradiation light beams having a first linear polarization direction, a scale configured to produce first and second diffraction light beams having the first linear polarization direction by diffracting the first and second irradiation light beams, respectively, the scale having a glass plate whose front surface has a grating shape, a polarizing unit configured to convert the first diffraction light beam into a third diffraction light beam having a second linear polarization direction which is perpendicular to the first linear polarization direction, to produce first and second composite light beams by combining the second diffraction light beam and the third diffraction light beam, and to convert the first composite light beam into a circularly polarized third composite light beam, and a light receiver configured to receive the second composite light beam and the third composite light beam.

Photoelectric encoder

An optical encoder includes a detection head. The detection head includes an optical system including a lens including a pair of bosses integrally formed with the lens and disposed with an optical axis of the lens therebetween, and an aperture plate having a pair of reference-pin-insertion holes disposed with an aperture therebetween; a housing including a pair of attachment portions and having a pair of lens-boss-insertion holes and a pair of reference-pin-insertion holes disposed on a central symmetry plane; a lens holder having a pair of lens-boss-insertion holes and a pair of reference-pin-insertion holes disposed on the central symmetry plane; and a pair of reference pins for positioning the lens holder and the aperture plate relative to the housing. An optical axis of the optical system is adjusted with respect to the bosses and the reference pins.

Optical encoder including scale having track and detection head for detecting the track

In a structure for protecting scale graduations, in which a graduation unit formed on a scale base is protected by a scale cover arranged on the top surface side of the graduation unit, a space between the scale base and the scale cover along the entire lateral periphery of the graduation unit is sealed using an adhesive agent mixed with a powder material such as a glass powder for blocking penetration of graduations-deteriorating components, to form a periphery adhesive layer. The scale cover may be supported on the scale base by a height regulating unit provided along the periphery of the graduation unit, so that variations in encoder output due to unevenness in thickness of the adhesive agent for joining the scale cover with the graduation unit can be prevented.

Structure for protecting scale graduations

A photoelectric encoder includes a scale in which diffraction gratings are formed at predetermined pitches in a measurement axis direction, a detection head which is relatively movable with respect to the scale, and which includes an illuminating portion configured to illuminate the scale, and a light receiving portion configured to receive light reflected by or transmitted through the diffraction gratings of the scale, a signal processing device configured to process a light reception signal output from the light receiving portion of the detection head, and a signal transmitting unit configured to transmit a signal between the detection head and the signal processing device. The signal processing device includes a display unit configured to display information indicating an attachment posture of the detection head with respect to the scale.

Photoelectric encoder and photoelectric encoder system

A photoelectric encoder has a scale in which a main track for detecting an amount of movement is formed in a measuring direction. The photoelectric encoder includes an origin signal generating portion provided at a part of the main track in a direction orthogonal to the measuring direction. Thereby, change in a light receiving signal due to passage of the origin signal generating portion is detected to generate an origin signal. Thus, the origin signal which is in agreement with a main signal in phase is obtained and improve the reproducibility of an origin position.

A photoelectric encoder includes: a scale; a detection head; fibers through which light that is to be irradiated on the scale and light reflected by the scale propagates; first and second cables each having a space in which the fibers are partially disposed; and a case that encloses a light source that supplies light to one of the fibers and a light-sensitive element that receives the reflected light propagating through the others of the fibers and converts the received light into an electric signal. The first cable, the second cable, and the case are disposed in this order in the direction of propagation of the reflected light. The positions of the fibers are fixed relative to one another inside the first cable in the direction orthogonal to the direction of length of the fibers and variable relative to one another inside the second cable in the orthogonal direction.

Photoelectric encoder including detection head and a plurality of fibers within a first and second cable

The present invention provides: a lens optical system having: a plastic lens; and a lens restraining member for mechanically restraining a thermal expansion of the plastic lens to control a variation of a curvature of lens due to a temperature change so as to suppress a variation of a focal position due to a temperature change; and a photoelectric encoder including the lens optical system.

Lens optical system and photoelectric encoder

A linear scale that is used for displacement measurement is provided. The linear scale includes a scale board, a graduation unit, and an attachment unit. The scale board is made of low expansion ceramics. The graduation unit is fixed to an upper surface of the scale board. The graduation unit is read at the time of measurement. The attachment unit is a unit for attaching the scale board to a base member.

Linear scale

The present invention provides: a lens optical system having a lens and a plastic block having two parallel planes, the plastic block being provided between the lens and a focal position of the lens to suppress a variation of a focal length due to a temperature change, and a photoelectric encoder including the lens optical system.

A photoelectric encoder using a lens array for dividing an image of a scale pattern into a plurality of regions to be detected and focusing them onto an array of light receiving elements, comprises, between the scale pattern and the lens array, a light-shielding array for reducing the effect of external disturbance light. The light-shielding array may be formed as a thin film pattern on a lens array side of a transparent cover glass which provides internal protection.

In a photoelectric encoder (incremental encoder and absolute encoder) having a detector that is displaceable relative to a scale having a predetermined pattern (incremental pattern and pseudorandom pattern) formed thereon, the detection range, to be simultaneously detected, of the pattern is divided in at least the detection direction, and a plurality of light-receiving systems are provided to detect each of the respective detection areas, whereby measurement of a wide detection range is enabled by using a small-sized and simple optical system and light-receiving system.

Photoelectric encoder having multiple light-receiving elements

An elastic fixture which is employed for attaching a length measuring apparatus to an object to be measured having a different linear expansion coefficient therefrom. The elastic fixture is elastically deformable in the lengthwise direction of the length measuring apparatus. The elastic fixture includes a sheet-metal curved beam having one end fixedly attached to the length measuring apparatus and the other end fixedly attached to the object to be measured. The sizes and the machining accuracy of the elastic fixture are less restricted, and the elastic fixture can be manufactured easily. In addition, the elastic fixture is applicable to relatively severe temperature environments in a manual machine tool or the like. Further, the sizes and the cost of the elastic fixture can be reduced as compared with a parallel spring mechanism.

Elastic fixture and attachment method for length measuring apparatus

A linear scale attachment device for holding and securely attaching a linear scale on an object to be measured is disclosed. The device includes an aluminum base formed with a holding groove having a larger opening than the width of a linear scale that is fitted in this groove, and a retainer for preventing the linear scale fitted in the holding groove from falling off. The base is permanently attached to the object at one location in the lengthwise direction, and resiliently attached at one or more other locations such as to be pressed in the X and Y directions using a cantilever plate spring. While using an aluminum base, the attachment device allows easy attachment and maintenance of the scale and relieves the effect of thermal stress caused by a difference in the thermal expansion coefficient between the aluminum base and the object.

Linear scale attachment device and attachment method

A multi-point frame-fixing unit type linear displacement measuring apparatus adapted to lessen the thermal stress while the strength of the apparatus with respect to an external force, such as vibration and an impact is maintained. Some portions of a frame of the apparatus in the length measuring direction are completely fixed to an object machine, and some other portions in the length measuring direction of the frame are elastically fixed to the object machine by using a bush provided with an elastic layer between the bush and the frame.

Multi-point frame-fixing unit type linear displacement measuring apparatus and method of fixing the same

An end fixing block fixed to one end in a length measuring direction of a frame body has a parallel plate spring mechanism capable of absorbing a thermal expansion of the frame body. The frame body has a plate spring mechanism which is provided at the end of the frame body fixed by the end fixing block, the plate spring mechanism being capable of absorbing a deflection of the one end of the frame body in a direction perpendicular to a direction to which the thermal expansion occurs.

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Kawasaki, Japan

Hiroaki Kawada