A photoelectric encoder includes light receiving units configured to output a plurality of photocurrent signals obtained by receiving light emitted from a light emission unit, via a scale, a signal conversion unit configured to output a conversion signal by converting the plurality of photocurrent signals, a position calculation unit configured to calculate an absolute position based on the conversion signal, and a microcomputer configured to perform drive control of the light emission unit, the signal conversion unit, and the position calculation unit. The microcomputer intermittently drives at least either one of the light emission unit and the signal conversion unit, and causes the position calculation unit to execute calculation according to a timing of intermit driving.

A robot includes a first member, a second member that is provided to be turnable about a turning axis with respect to the first member, marks that are disposed around the turning axis on a surface of the second member, and a mark detection portion that is disposed in the first member and detects the marks.

A rotation angle detection device that is capable of detecting an absolute rotation position with a high accuracy without an error. A rotation detection target rotates together an operatable rotation member and has an outer scale and an inner scale. Two rotation detection elements are arranged at opposite positions across the rotation axis in the radial direction so as to respectively irradiate the outer and the inner scales with light beams and output signals corresponding to reflected components. A control unit calculates a rotation angle of the rotation detection target using the signals. The outer and inner scales are so formed that a signal output from one of the two rotation detection elements increases and the signal output from the other decreases when the rotation member is rotated.

An absolute encoder includes a scale having a sequence of marks, a detector configured to detect a signal corresponding to a plurality of marks of the scale, and a processor configured to obtain an absolute position corresponding to the signal. The processor is configured to select code sequences, from a group of code sequences corresponding to absolute positions, as a candidate group for a code sequence corresponding to the signal, and to select the code sequence corresponding to the signal from the candidate group.

The invention relates to a detector device having pixels in a two-dimensional arrangement, the detector device comprising row pixels, a row readout wiring for each row of said row pixels and a column select wiring for each column of said row pixels, as well as column pixels, a column readout wiring for each column of said column pixels and a row select wiring for each row of said column pixels. Analog-to-digital converters adapted for row-parallel and column-parallel operation are connected to the readout wirings, and simultaneously one or more columns of row pixels for row parallel readout and one or more rows of column pixels for column parallel readout can be selected. The invention further relates to a positioning code and to a position detecting method.

An encoder apparatus comprising a scale and a readhead assembly comprising a scale signal receiver. The scale and the scale signal receiver are located within a protective housing which is configured to protect them from contamination located outside the protective housing and comprises a seal through which the scale signal receiver can be connected to a part outside the protective housing. The arrangement of the scale signal receiver inside the protective housing is independent of the scale and protective housing.

A rotary encoder for detecting the angle of rotation of a first rotatable shaft, with a first mark which is coupled with the first shaft, a second mark which is coupled with the second rotatable shaft, a third mark which is coupled with the second shaft, a fixed fourth mark and means for detecting a passage of the third mark though a vicinity of the fourth mark and means for detecting a coincidence of the angles of rotation of the first and the second marks.

A sealed encoder module for mounting onto a machine so as to measure relative displacement of first and second parts of the machine. The sealed encoder module can comprise, a scale, a readhead comprising a scale signal receiver, and an integral protective housing which encapsulates at least the scale and said scale signal receiver. The sealed encoder module can be configured to determine and output diagnostic information regarding a scale signal detected by the readhead.

There is provided an absolute position detection type photoelectric encoder which improves robustness to dirt while maintaining high resolution. A two-level code pattern according to a pseudo random code sequence is provided on a scale along a length measurement direction. Each code of the two-level code pattern indicates a code 1 or a code 0, and includes two bits. Each of the two bits is L or H. The code 1 is represented by an A pattern which is a combination of L and H, and the code 0 is represented by a B pattern which is a combination of L and L or a C pattern which is a combination of H and H. When the codes 0 are continued, the B pattern and the C pattern are alternately used.

Disclosed embodiments include a two-dimensional scale with a simple arrangement capable of omitting setting of an origin mark in the Y-axis direction. In a linear scale, a reference origin mark array and a tilting origin mark array that is a tilting marker array are provided in an origin mark region. Since the reference origin mark array is parallel to X-coordinates, an X-direction origin signal is correctly generated. On the other hand, for the Y direction in which no origin mark is provided, the distance between a reference origin mark and a tilting origin mark is detected. A Y-direction absolute position is decided in accordance with the distance.