An information processing apparatus includes an acquisition unit configured to acquire a first phase signal and a second phase signal that are acquired by measuring a rotation of a moving object, and a calculation unit configured to calculate a rotational angle by an iterative calculation so as to satisfy a relational expression bearing an arctangent. The relational expression bearing the arctangent uses a first cosine wave and a second cosine wave at a higher harmonic of the first cosine wave for the first phase signal, and a first sine wave and a second sine wave at a higher harmonic of the first sine wave for the second phase signal. The first phase signal and the second phase signal may, for example, be analog signals having a wave shape.

An example apparatus is described which comprises a rotary member supported by a bearing. A rotary encoder is registered with respect to the rotary member to rotate therewith and a sensing arrangement is registered with respect to a surface of the bearing. The sensing arrangement is responsive to rotation of the encoder to generate a signal indicative of a rotational characteristic of the rotary member.

A scale fixating device includes a fixing block unmovably fixating a first end of a scale to an object, and a pulling block fixating a second end of the scale to the object while pulling the second end of the scale to the second end side. The pulling block includes a fixated base fixated to an object, a slide holding the second end of the scale and installed slidably with respect to the fixated base, and a pulling mechanism having a first end engaged to the slide and a second end engaged to the fixated base, the pulling mechanism pulling the slide toward the second end relatively with respect to the fixated base. The scale fixating device either prevents a friction force from changing between the slide and the fixated base or generates an extremely large friction force between the slide and the fixated base.

A scale (20) has a plurality of patterns so as to spatially modulate an energy distribution, and the scale includes a first pattern having a first modulation period in a moving direction, and a second pattern having a second modulation period different from the first modulation period in the moving direction, a relative phase between the first pattern and the second pattern changes in accordance with a direction perpendicular to the moving direction, each of the first pattern and the second pattern is configured by including a reflective portion (26) that reflects light and a non-reflective portion (25) that does not reflect the light, and a width of the reflective portion (26) in the moving direction at a first position is different from the width at a second position different from the first position along the direction perpendicular to the moving direction.

An index grating of an optical encoder provided by the invention has a main technical feature of increasing a ratio of light-transmissible area of a grating per unit area, thereby increasing a light source utilization efficiency and a signal intensity, and reducing light-blocking ratio caused by dust and other foreign matters, thereby reducing a degree of influence on light intensity, so as to improve a sensing precision of the optical encoder.

A rotary laser emitting apparatus that rotates and emits a laser beam comprises an emission-side control unit that controls an entire operation of the apparatus, a laser emitting mechanism that emits the laser beam while rotating an irradiation optical axis that is an emission direction of the laser beam, and a rotating direction detecting unit that detects a rotating direction of the irradiation optical axis. The emission-side control unit generates a rotating posture signal showing the rotating direction of the irradiation optical axis detected by the rotating direction detecting unit and drives the laser emitting mechanism for superimposing the rotating posture signal on the laser beam.

In an optical position measuring device for detecting the relative position of a first measuring standard and a second measuring standard, movable relative to each other along at least one measuring direction, at a splitting grating, a beam bundle emitted by a light source is split up into at least two partial beam bundles. When passing through scanning beam paths, the partial beam bundles undergo different polarization-optical effects. After the differently polarized partial beam bundles are recombined at a combination grating, a plurality of phase-displaced, displacement-dependent scanning signals is able to be generated from the resulting beam bundle. No polarization-optical components are arranged in the scanning beam paths of the partial beam bundles between the splitting and recombination. To generate the different polarization-optical effects on the partial beam bundles, a conically incident illumination beam bundle impinges upon the splitting grating, the incident illumination beam bundle extending in a plane perpendicular to the measuring direction at an angle other than 0°, the plane of incidence being defined by the grating normal to the splitting grating and the direction of incidence of the illumination beam bundle. The scanning beam paths of the partial beam bundles are arranged in mirror symmetry with respect to the plane of incidence between the splitting and recombination.

The instant disclosure provides an optical scanning light-guiding encoder including a light-guiding grating wheel, a light-emitting module and an optical sensing module. The optical sensing module includes a plurality of sensor elements adjacent to the light-guiding grating wheel, and a plurality of exposed sensor areas of the plurality of sensor elements are offset in the transverse direction and are arranged along a plurality of different horizontal lines parallel to each other. The optical scanning light-guiding encoder provided by the instant disclosure utilizes the coordination of the light projected on the optical sensing module and the plurality of exposed sensor areas to increase the resolution thereof without increasing the size of the encoder and the number of blades thereof.

An optical sensor, an optical encoder, a torque detection apparatus, and an electric power steering apparatus less affected by fluctuations in the amount of detected light and with an improved resolution are provided. The optical sensor includes a first polarizing layer that splits incident light to light with a first polarization direction, a first photoreceiver that receives first polarized light split by the first polarizing layer, a second polarizing layer that splits the incident light to light with a second polarization direction, and a second photoreceiver that receives second polarized light split by the second polarizing layer. The first photoreceiver and the second photoreceiver are positioned alternatingly and spaced uniformly with each other.

An optical sensor including a light-emitting element, four light-receiving elements facing the light-emitting element, and a substrate at which the light-emitting element and the light-receiving elements are provided. The substrate includes a first portion at which the light-emitting element is provided and a second portion at which the light-receiving elements are provided, the first portion and the second portion being integrated. Respective distances from the four light-receiving elements to one point on a predetermined plane are equal, four line segments that connect the one point and centers of respective light-receiving regions of the four light-receiving elements form right angles with each other, and a normal line of the predetermined plane that passes through the one point passes through an emission point of the light of the light-emitting element or a center of an emission surface of the light of the light-emitting element.