In order to provide a detection device that can accurately detect thermal deformation in any state including a case where thermal deformation has already occurred, there is provided a detection device which includes: a scale with a strained grating; and two sensor heads mounted on a pedestal at a predetermined distance, the sensor heads detecting positions on the scale based on the grating. Thermal deformation of the pedestal or the scale is detected based on a change in a difference between the positions detected by the two sensor heads.

A main object of the present disclosure is to provide a reflection-type optical encoder scale capable of sufficiently reducing the reflectance on a low reflection region. The present disclosure achieves the object by providing a reflection-type optical encoder scale comprising a high reflection region and a low reflection region alternately placed on a substrate, wherein the low reflection region includes a low reflection portion including a metallic chromium film formed on the substrate, and a chromium oxide film and a chromium nitride film randomly formed on the metallic chromium film; and the high reflection region has higher reflectance of incident light from opposite side to the substrate of the reflection-type optical encoder scale, than the low reflection region.

There is provided an optical encoder with alignable relative positions between elements including an encoding medium, a sensor package and a memory. The sensor package includes a photodiode array and two alignment photodiodes opposite to the encoding medium. The memory records an alignment pattern associated with output signals of the two alignment photodiodes when the encoding medium and the sensor package are at nominal operating positions. When the encoding medium and the sensor package are not at the nominal operating positions, the relative position alignment is performed by adjusting current relative positions between the encoding medium and the sensor package to cause a current pattern associated with output signals of the two alignment photodiodes to be identical to the alignment pattern.

A rotation angle encoder apparatus is disclosed. The rotation angle encoder apparatus may comprise a plurality of light sources, a plurality of light detectors, and a plurality of pinions rotatable about a shaft. Each of the pinions may comprises a plurality of teeth and a plurality of gaps. The rotation angle encoder apparatus may comprise a plurality of stacked configurations such that, when the shaft is rotated, transmissivity may be measured to determine or calculate at least one measurement, such as an angle of rotation, position, movement, distance, or other discernable measurement. The rotation angle encoder apparatus with a plurality pinions and associated measurable transmissivities may enable an optical spectrum analyzer to increase wavelength accuracy and improve resolution in optical measurements.

A light-emitting unit includes: a light source; and a reflector having reflection faces of first and second partial paraboloids, the first and second partial paraboloids being spaced from each other in an optical axis direction of the light source, the first and second partial paraboloids having a focal point on the light source, wherein: the second partial paraboloid is between the light source and the first partial paraboloid in the optical axis direction; the second partial paraboloid has a coefficient different from that of the first partial paraboloid; and the second partial paraboloid is positioned on a reflection direction side of a light from the light source reflected by the first partial paraboloid, with respect to a plane that is obtained on a presumption that the first partial paraboloid is extended to the light source side in accordance with the coefficient of the first partial paraboloid.

An encoder includes a disc and a sensor. The disc has a circular surface with a central axis and is rotatable around the central axis. The disc has a slit row provided on the circular surface. The slit row includes slits arranged in a circumferential direction of the circular surface around the central axis and in a radial direction of the circular surface. The sensor is provided opposite to the slit row on circular surface. The sensor has a first light receiver and a second light receiver. The first light receiver is configured to output a first light receiving signal as the slit row rotates along the circumferential direction when the disc rotates around the central axis. The second light receiver is configured to output a second light receiving signal as the slit row moves along the radial direction when the disc rotates around the central axis.

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.

A position detecting member includes a base portion including a light-receiving surface having a black color tone and a back surface located on an opposite side to the light-receiving surface. A surface layer portion including at least the base portion is made of ceramic. An average value of root mean square slopes (RΔq) on the light-receiving surface in a roughness curve is larger than an average value of root mean square slope (RΔq) on the back surface.

A rotary encoder includes a rotating shaft, first and second encoder wheels, first and second detectors and a processor. The first encoder wheel includes coaxially disposed first and second portions. The first portion has first graduation features. The second portion has a first positioning structure. The second encoder wheel includes coaxially disposed third and fourth portions. The third portion has second graduation features. The fourth portion has a second positioning structure meshing with the first positioning structure, so that the first graduation features and the second graduation features are staggered, and the first encoder wheel and the second encoder wheel are coaxially mounted on the rotating shaft. The first and second detectors detect the first and second graduation features and output first and second signals, respectively. The processor calculates a rotating angle of the rotating shaft according to the first and second signals.

A position detection device, for detecting a change in relative position of a detection object with respect to a reference portion, includes: a base portion immovable with respect to the reference portion; a following portion deformable or movable following relative movement of the detection object with respect to the reference portion; an expandable and contractible member; and a heat flux detection section. The expandable and contractible member is provided between the base portion and the following portion, is made of a material expandable and contractible according to deformation or movement of the following portion, and generates heat during contraction and absorbs heat during expansion. The heat flux detection section is provided to be subjected to heat of the expandable and contractible member, and is configured to detect a heat flux that is a flow of heat between an inside and an outside of the expandable and contractible member.