Abstract: An offset correction device includes: an amplitude adjuster that adjusts an amplitude of a detection signal output from an encoder by adjusting a gain of the detection signal so that the amplitude is within a predetermined range; an offset corrector that corrects an offset of an amplitude center of the detection signal; and a storage that stores a relationship between the gain and an offset amount in advance, wherein the offset corrector refers to the relationship stored in the storage when the amplitude adjuster changes the gain, obtains the offset amount corresponding to the changed gain, and corrects the offset based on the obtained offset amount.

Abstract: An electromagnetic induction type encoder, wherein at least one of widths of a first transceiver coil, a first plurality of conductors and a first receiver coil of a first track in a direction vertical to facing direction between a detection head and a scale and a measurement direction is different from corresponding width of a second transceiver coil, a second plurality of conductors and a second receiver coil in the direction vertical to the facing direction and the measurement direction.

Abstract: An offset correction device includes: an amplitude adjuster that adjusts an amplitude of a detection signal output from an encoder by adjusting a gain of the detection signal so that the amplitude is within a predetermined range; an offset corrector that corrects an offset of an amplitude center of the detection signal; and a storage that stores a relationship between the gain and an offset amount in advance, wherein the offset corrector refers to the relationship stored in the storage when the amplitude adjuster changes the gain, obtains the offset amount corresponding to the changed gain, and corrects the offset based on the obtained offset amount.

Abstract: An electromagnetic induction type encoder, wherein at least one of widths of a first transceiver coil, a first plurality of conductors and a first receiver coil of a first track in a direction vertical to facing direction between a detection head and a scale and a measurement direction is different from corresponding width of a second transceiver coil, a second plurality of conductors and a second receiver coil in the direction vertical to the facing direction and the measurement direction.

Abstract: An electromagnetic induction type encoder, wherein a detection head has a drive coil generating magnetic flux, wherein a scale has a plurality of connection coils arrayed in a fundamental period ? in a measurement axis direction, are electromagnetically coupled with the magnetic flux generated by the drive coil and generates magnetic flux fluctuating in a predetermined spatial period in the measurement axis direction, wherein the detection head has a plurality of receiver coils arrayed in the fundamental period ? in the measurement axis direction and are electromagnetically coupled with the magnetic flux generated by the plurality of connection coils and detects a phase of the magnetic flux, wherein ?/2?2d<L<?/2 is satisfied when a distance between line width centers of the plurality of connection coils is “L” and a line width of the plurality of connection coils is “d”.

Abstract: Provided is an encoder that can sense an abnormality in the attitude of a detector with respect to a scale. An encoder includes a scale and a detector, the scale being provided on one measurement target part with marks arranged on the scale, and the detector being provided on another measurement target part and configured to detect an amount of relative movement with the scale. The scale includes a sensing unit that senses the attitude of the detector with respect to the scale, and thus even in a case where an abnormality in the attitude of the detector with respect to the scale cannot be sensed on the basis of a change in a signal read by a reading unit, the abnormality can nevertheless be sensed.

Abstract: An electromagnetic induction type encoder, wherein a detection head has a drive coil generating magnetic flux, wherein a scale has a plurality of connection coils arrayed in a fundamental period ? in a measurement axis direction, are electromagnetically coupled with the magnetic flux generated by the drive coil and generates magnetic flux fluctuating in a predetermined spatial period in the measurement axis direction, wherein the detection head has a plurality of receiver coils arrayed in the fundamental period ? in the measurement axis direction and are electromagnetically coupled with the magnetic flux generated by the plurality of connection coils and detects a phase of the magnetic flux, wherein ?/2?2d<L<?/2 is satisfied when a distance between line width centers of the plurality of connection coils is “L” and a line width of the plurality of connection coils is “d”.

Abstract: Provided is an encoder that can sense an abnormality in the attitude of a detector with respect to a scale. An encoder includes a scale and a detector, the scale being provided on one measurement target part with marks arranged on the scale, and the detector being provided on another measurement target part and configured to detect an amount of relative movement with the scale. The scale includes a sensing unit that senses the attitude of the detector with respect to the scale, and thus even in a case where an abnormality in the attitude of the detector with respect to the scale cannot be sensed on the basis of a change in a signal read by a reading unit, the abnormality can nevertheless be sensed.

Abstract: An optical encoder includes a light source fiber holder holding a light source fiber and a collecting lens therein, and a nut. The light source fiber holder includes an end fitting together with a light source base. An outer circumferential surface of the end includes an inclined surface inclining such that a cross-sectional area increases as the surface approaches the light source fiber; and a projection capable of advancing into a groove of the light source base. The optical encoder includes a light source connector and the light source fiber holder.

Abstract: An optical encoder includes a scale having bar-like scale marks; a detection head having a light source fiber emitting coherent light at the scale and a photoreceiver fiber receiving light reflected off the scale; electronic components connected to the detection head via the light source fiber and the photoreceiver fiber; and a protector covering the scale marks at a predetermined distance from the scale marks. The protector is a member configured with light-transmissive material and includes a top surface that is inclined with respect to a principal surface of the scale.

Abstract: An optical encoder includes a light source fiber holder holding a light source fiber and a collecting lens therein, and a nut. The light source fiber holder includes an end fitting together with a light source base. An outer circumferential surface of the end includes an inclined surface inclining such that a cross-sectional area increases as the surface approaches the light source fiber; and a projection capable of advancing into a groove of the light source base. The optical encoder includes a light source connector and the light source fiber holder.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.