There is provided an optical encoder including a photodiode array and a code disk opposite to each other. The photodiode array includes at least three sets of position photodiodes and two index photodiodes arranged transversally. The two index photodiodes are adjacently arranged at the same side of the at least three sets of position photodiodes. A first set of position photodiodes and a last set of position photodiodes of the at least three sets of position photodiodes are partially covered to alleviate the total harmonic distortion. The rest position photodiodes of the at least three sets of position photodiodes other than the first and last sets of position photodiodes are not covered.

A detection method includes obtaining first count data and second count data during rotation of an encoder disc mounted at and configured to rotate together with a rotation object and determining a rotation parameter of the rotation object according to the first count data and the second count data. The encoder disc includes N detection target portions arranged along a circumferential direction of the encoder disc. The N detection target portions include N−K first detection target portions and K second detection target portions. Along the circumferential direction of the encoder disc, a width of one of the N−K first detection target portions is different from a width of one of the K second detection target portions. The first count data is obtained when one detection target portion of the N detection target portions is detected. The second count data is recorded between two neighboring detection target portions.

An optical encoder is provided. The encoder includes an optical disc mounted on a shaft, the optical disc containing pit and land markings; an optical pickup unit for an optical disc that receives light from the optical disc and supplies as an output an electrical signal representative of the received light, comprising: a reading head objective lens, and dynamic steering actuators that control the focus and tracking of the reading head objective lens; a processor that receives as an input the electrical signal from the optical pickup unit and reports motion of the substrate based on the received at least one electrical signal.

A controller for use with a position encoder includes one or more motion inputs suitable to couple to motion outputs of the position encoder and a limit input suitable to couple to a limit output of the position encoder. The controller also includes an actuator interface, a command interface, and circuitry coupled to the one or more motion inputs, the limit input, the actuator interface, and the command interface. The circuitry is configured to receive a command through the command interface to move a structural member coupled to the position encoder to a new position and control an actuator through the actuator interface to move the structural member toward the new position. A limit indication is received from the position encoder through the limit input and the controller stops or reverses the movement of the structural member by controlling the actuator in response to receiving the limit indication.

A reference voltage generator circuit generates a reference voltage corresponding to a power supply voltage. A current/voltage converter circuit converts a photocurrent output by a photoreceiver into voltage, and outputs a voltage obtained by adding the converted voltage and the reference voltage. A sample and hold circuit holds a voltage of a capacitor in response to a sample and hold signal, the capacitor having the voltage input at one end and the reference voltage input at another end. An amplifier circuit outputs an output signal where a voltage held by the sample and hold circuit is amplified with the reference voltage as a reference.

A method is provided for spatially modulating electromagnetic radiation at high frequency where the modulation is phase, polarization or direction of propagation comprises a substrate carrying an ordered array of optical elements in relative motion with respect to an incident beam of electromagnetic radiation to be modulated and measuring the relative motion. The array contains at least three optical elements and at least two different types of optical elements. At least some of the optical elements are formed from and integral to the substrate material. The optical elements may be fabricated on the substrate material by a subtractive process. The electromagnetic radiation to be modulated is incident on a region of the substrate termed the active region. As the substrate moves relative to the incident electromagnetic radiation, the active region also moves and the designation of individual optical elements changes also.

For providing an apparatus and method for providing a graphic representation (1) or a graphic representation sequence for detection by a detector (3) which provide a simple and effective variation of a graphic representation (1) or a graphic representation sequence for detection by the detector (3) an apparatus is claimed, comprising: a sequence of graphic representations (1) along an optical axis (2), an optical device (4) for focusing on at least one of the graphic representations (1), so that the at least one of the graphic representations (1) is visible by a detector (3) preferably with a predefinable sharpness, a control unit (5) for defining and providing a focusing sequence on the at least one of the graphic representations (1) by the optical device (4) for providing a change of visibility of the graphic representations (1) or of a part of the graphic representations (1) by the detector (3) in order to allow for the verification of the correct functioning of the detector.

A scale includes: a substrate; scale gratings that are formed on a face of the substrate and has a plurality of gratings at a predetermined interval; and a protective layer that is made of fluoride and covers the scale gratings and an exposed portion of the face of the substrate.

A position detection encoder includes a scale that has a position detection pattern and a linear pattern that is formed in a direction parallel to a length direction of the position detection pattern; and a position detector generating a position detection signal with a different value due to a displacement of the position detection pattern in the length direction. In the position detector, a position confirmation pattern is formed that includes two markers arranged at an interval equal to or less than an offset tolerance value for a positional relationship of the position detector and the scale in a width direction of the position detection pattern.

A method for forming an assembly of a plurality of components. The method includes receiving, by a controller, one or more assembly identification parameters and controlling, by the controller, a light array disposed along an assembly jig based on the one or more assembly identification parameters.