An encoder apparatus includes a detection unit, a scale disposed to oppose the detection unit and relatively rotatable with respect to the detection unit, and a processor configured to process an output signal output from the detection unit to obtain a relative position of the scale with respect to a standard position and thus detect an absolute position of the scale. The processor is configured to execute a setting process in which a position where a deviation amount of the scale in a predetermined direction with respect to a rotation axis is equal to or smaller than a threshold value is set as the standard position, the deviation amount changing in accordance with relative rotation of the scale with respect to the detection unit.

An encoder including a rotary disc that rotates around a rotating shaft, and a sensor that detects a rotational position of the rotary disc, in which the rotary disc is provided with first patterns and second patterns, the first patterns are arranged at positions obtained by equally dividing a first circumference which is a circumference of a first circle into M (M is natural number of 2 or more) at intervals, the second patterns are arranged at positions obtained by equally dividing a second circumference which is a circumference of a second circle which is a concentric circle of the first circle and has a different radius from that of the first circle into N (N is natural number of 2 or more) at intervals, and M and N are different from each other and a greatest common divisor of M and N is 1.

An encoder is provided that is capable of suppressing accuracy deterioration even if a scale is disposed in a tilted manner with respect to a receiving unit by being rotated around an axis (i.e., a rotation axis) orthogonal to a receiving surface. The encoder 1 includes scale 2 and detection head 3. The detection head 3 includes light source (transmitting unit) 4 and light-receiving unit (receiving unit) 5. The light-receiving unit includes light-receiving surface (receiving surface) 50 and converts light received at the light-receiving surface 50 into differential detection signals with two phases and outputs the same. The light-receiving surface 50 includes element array group 7 including four element arrays 71-74 provided in a parallel manner along an orthogonal direction, with each element array 71-74 including a plurality of light-receiving elements (receiving elements) 500. The plurality of element arrays 71-74 in the element array group 7 are disposed at positions where the sum of: (i) a distance in the orthogonal direction from a reference position to a positive phase signal element array 71, 72; and (ii) a distance in the orthogonal direction from the reference position to the negative phase signal element array 73, 74, is the same for all the phases of the at least two phases.

An encoder apparatus includes an encoder and a processor. The encoder includes a scale portion, a light emitting portion, and a light receiving portion. The scale portion includes a first track and a second track. The processor obtains a plurality of candidate values of a gap between the light emitting portion and the scale portion on a basis of an amplitude of a first signal obtained by receiving light reflected on or transmitted through the first track by the light receiving portion. The processor determines a measured value from among the plurality of candidate values on a basis of an amplitude of a second signal obtained by receiving light reflected on or transmitted through the second track by the light receiving portion.

An encoder includes scale and detection head. The detection head includes light source (transmitting unit) and light-receiving unit (receiving unit). The light-receiving unit includes light-receiving surface (receiving surface) and converts light received at the light-receiving surface 50 into differential detection signals with two phases and outputs the same. The light-receiving surface includes element array group including four element arrays provided in a parallel manner along an orthogonal direction, with each element array including a plurality of light-receiving elements (receiving elements). The plurality of element arrays in the element array group are disposed at positions where the sum of: (i) a distance in the orthogonal direction from a reference position to a positive phase signal element array; and (ii) a distance in the orthogonal direction from the reference position to the negative phase signal element array, is the same for all the phases of the at least two phases.

An encoder apparatus includes a detection unit, a scale disposed to oppose the detection unit and relatively rotatable with respect to the detection unit, and a processor configured to process an output signal output from the detection unit to obtain a relative position of the scale with respect to a standard position and thus detect an absolute position of the scale. The processor is configured to execute a setting process in which a position where a deviation amount of the scale in a predetermined direction with respect to a rotation axis is equal to or smaller than a threshold value is set as the standard position, the deviation amount changing in accordance with relative rotation of the scale with respect to the detection unit.

A position detection method includes obtaining a first phase value of a first signal that repetitively changes by a first cycle number, a second phase value of a second signal that repetitively changes by a second cycle number larger than the first cycle number, and a third phase value of a third signal that repetitively changes by a third cycle number larger than the second cycle number, selecting one cycle corresponding to the first phase value from cycles of the second cycle number, selecting one cycle corresponding to the second phase value and the cycle selected from the cycles of the second cycle number, obtaining a fourth phase value of the third signal corresponding to the second phase value of the cycle selected from the cycles of the second cycle number, and obtaining a position of the scale by using the third phase value and the fourth phase value.

There is provided a position detection device to suppress an influence of a signal distortion due to a processing error or the like, the position detection device including: a reference position calculation unit that calculates a reference position of a moving body on the basis of a first signal and a second signal, the first signal being detected from a first track provided on the moving body and having a scale of predetermined cycles, and the second signal being detected from a second track provided on the moving body and having a scale of cycles less than the predetermined cycles; a slit specifying unit that specifies a slit corresponding to a position of the moving body; an in-slit position calculation unit that calculates an in-slit position of the moving body in the specified slit; and a correction unit that corrects an absolute position of the moving body.

A digital adaptive optics encoder module includes an input mounting flange, a collimating lens, a bandpass filter, digital adaptive optic elements, refocusing lens, an output mounting flange, and a housing. The input mounting flange is capable of attaching to a telescope. The collimating lens is capable of expanding light from a target to fill a plurality of primary apertures. The bandpass filter has a bandwidth ranging from about 40 nm to about 100 nm. The digital adaptive optic elements include the plurality of primary apertures, an optical spreader, a focusing optic, and a detector. The refocusing lens is capable of refocusing an output from the digital adaptive optic elements onto a sensor plane. The output mounting flange is capable of attaching to an output connection. The housing encloses all of the interior components of the digital adaptive optics encoder module.

There is provided a position detection device to suppress an influence of a signal distortion due to a processing error or the like, the position detection device including: a reference position calculation unit that calculates a reference position of a moving body on the basis of a first signal and a second signal, the first signal being detected from a first track provided on the moving body and having a scale of predetermined cycles, and the second signal being detected from a second track provided on the moving body and having a scale of cycles less than the predetermined cycles; a slit specifying unit that specifies a slit corresponding to a position of the moving body; an in-slit position calculation unit that calculates an in-slit position of the moving body in the specified slit; and a correction unit that corrects an absolute position of the moving body.