A measurement device has: a slider which holds a substrate and is movable parallel to the XY plane; a drive system that drives the slider; a position measurement system which emits beams from a head section to a measurement surface in which grating section are provided on the slider, which receives respective return beams of the beams from the measurement surface, and which is capable of measuring position information in at least directions of three degrees of freedom including the absolute position coordinates of the slider; a mark detection system that detects a mark on the substrate; and a controller which detects the marks on the substrate using the mark detection system while controlling the drive of the slider, and which obtains the absolute position coordinates of each mark based on the detection result of each mark and measurement information by the position measurement system at the time of detection.

An optical module includes a fixed substrate, and a sensor substrate secured to the fixed substrate and having a through-hole formed therein. A light emitting device is secured to the fixed substrate at a position in the through-hole. A light receiving device is provided in the sensor substrate. A dummy light receiving device is formed between the light receiving device and the through-hole, around the through-hole, and in the sensor substrate. The light receiving device and the dummy light receiving device are made of an impurity diffusion layer having a same conductive type as a conductive type of a surface layer of the sensor substrate. The dummy light receiving device is deeper than the light receiving device.

An improved optical encoder uses an optical pick-up unit that provides for degrees of freedom in the tracking and focus axes that are unavailable in conventional optical encoders thereby improving the encoders' performance. In an embodiment the encoder employs an optical disc marked with pits and lands which may be arranged in a spiral pattern. The optical disc is mounted on the shaft whose motion is to be monitored by the optical encoder. The encoder may be arranged to read the markings on the optical disc using the three-beam pickup method.

A plug gauge includes a housing, defining an internal volume, first openings, and second openings. The plug gauge includes first contact elements, each at least partially received in a respective one of the first openings. The plug gauge includes a first plunger in the internal volume and movable relative to the housing. The first plunger is biased to urge the first contact elements radially outward through the first openings. The plug gauge includes a first sensor sensing movement of the first plunger. The plug gauge includes second contact elements, each at least partially received in a respective one of the second openings. The plug gauge includes a second plunger in the internal volume and movable relative to the housing. The second plunger is biased to urge the second contact elements radially outward through the second openings. The plug gauge includes a second sensor sensing movement of the second plunger.

A position-measuring device includes a graduation carrier which carries a measuring graduation and is non-rotatably connectable to a shaft. A scanner is configured to generate scanning signals by scanning the measuring graduation. Evaluation electronics are configured to process the scanning signals into a digital angle value of the shaft. An interface is configured to communicate with subsequent electronics. The scanner is mountable on a machine part that is supported so as to be movable in an axial direction of the shaft, so that the scanning signals are dependent on a position of the machine part in the axial direction of the shaft, and so that a measure of the position of the machine part in the axial direction of the shaft is determinable from the scanning signals by the evaluation electronics.

An optical encoder includes a light source, a plurality of diffraction gratings including grating faces on which a plurality of grooves are disposed in parallel, and a light-receiving unit configured to receive the light diffracted at the plurality of diffraction gratings. The diffraction gratings include a first diffraction grating that is a first-stage diffraction grating adjacent to the light source, a third diffraction grating that is a last-stage diffraction grating adjacent to the light-receiving unit, and a second diffraction grating that is an output-stage diffraction grating of the first-stage diffraction grating and an input-stage diffraction grating of the last-stage diffraction grating. The diffraction gratings are disposed such that the ratio of the first gap to the third gap equals the ratio of the second gap to the fourth gap, and a length of the first gap differs from a length of the second gap.

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.

In an exposure apparatus, on a substrate holder, a plurality of grating areas is arranged mutually apart in the X-axis direction, and a plurality of heads that irradiates a measurement beam with respect to the grating area and can move in the Y-axis direction is arranged outside of the substrate holder. A control system controls movement of the substrate holder in at least directions of three degrees of freedom within an XY plane, based on measurement information of at least three heads of the plurality of heads facing the grating area and measurement information of a measurement device that measures position information of the plurality of heads. The measurement beam of each of the plurality of heads, during the movement of substrate holder in the X-axis direction, moves off of one of the plurality of grating areas and switches to another adjacent grating area.

A life detection device of an encoder is used for the encoder including a scale and a head. The scale is housed in a scale frame. The head relatively moves along the scale to detect an amount of relative movement with the scale. The life detection device includes environmental condition detection means, life determination means, and informing means. The environmental condition detection means is configured to detect an environmental condition related to life detection in the encoder. The life determination means is configured to determine a life of a component constituting the encoder based on a detection result by the environmental condition detection means. The informing means is configured to inform the life based on a determination result by the life determination means.

By configuring an encoder scale as an angled or inclined magnet or pair of oppositely arranged, adjacent magnets, a magnetic field sensor in a travel path of the scale can detect an absolute position of the scale for use in an industrial control system. Due to the angle or incline, when a first side of the scale is proximal to the sensor, the sensor can detect an angle of 180. As the scale moves to center with respect to the sensor, the sensor can detect an increasing angle to 0. Then, as a second side of the scale becomes proximal to the sensor, the sensor can detect an increasing angle to +180. The angle changes linearly with position. In one aspect, the pair of oppositely arranged magnets can be rotated with respect to the travel path to provide the angle. In another aspect, the pair of oppositely arranged magnets can be magnetized diagonally to provide the angle.