Abstract: A wafer pre-alignment apparatus according to this invention includes a wafer rotating member, a rotation detecting member, a light emitting member for emitting light toward the periphery of the wafer, a COD linear sensor linearly arranged and signal processing member for detecting the edge position of the wafer to acquire at least one of an orientation flat position, notch position and center position of the wafer on the basis of the edge position detected, and further includes an up-down counter for converting a signal received from the rotation detecting member into rotating position information, a measured angle setting register for storing the rotation position information when the wafer rotating member rotates by an interval angle and a comparator for comparing a set value in the measured angle setting register and a counted value in the up-down counter.

Abstract: An absolute encoder comprising a first memory operable to store a first absolute value signal produced every constant time period, the absolute value signal representing an absolute value position. A second memory stores a second absolute value signal produced in a previous time period. A comparing/calculating section compares the first absolute value and the second absolute value and produce a difference amount. A dividing process section divides the difference amount in an equal rate within a producing time period of said first absolute value signal. An interpolated absolute value signal producing section reads the second absolute value signal and adds the difference amount in a stepwise manner.

Abstract: A prealignment sensor comprising a frame fixed to a base and having a U-shape when viewed from its side. A light source is attached to a lower part of the flame. A convex lens is attached to a lower part of an inside of the frame by which diffused light of the light source is transformed into parallel light. A lens holder is provided for fixing the convex lens to the frame. An optical receiver is attached to an upper part of an inside of the frame by which the parallel light is received and is transformed into an electrical signal. A signal processing circuit is attached to the frame by which the electric signal is transformed into a desired displacement magnitude. The frame is formed of aluminum subjected to sulfuric-acid hard alumite treatment and then to steam sealing.

Abstract: A wafer prealignment apparatus comprising a CCD linear sensor and a wafer prealignment method which facilitate the sensing of wafer presence, improvement in precision of position sensing, and edge sensing adapted to the material of the wafer even of the material is transparent or not. A photodiode (27) is provided in a vicinity of the first pixel from the center shaft of the wafer rotation means of a CCD linear sensor (5) to detect a wafer (1) on the basis of the luminous energy value. The time from the issuance of a measurement command to the sensor (5) to that of an ROG signal for transmitting the detection timing of the sensor (5) is measured to correct the angular error of a measurement position due to the rotation during this measurement. For sensing an edge position of the wafer (1), the scan start point of the sensor (5) is set on the opposite side of the center shaft of the wafer rotation means. When the wafer is transparent a sense signal is binarized to set its change point as the edge position.

Abstract: A wafer prealignment apparatus comprising a CCD linear sensor and a wafer prealignment method which facilitate the sensing of wafer presence, improvement in precision of position sensing, and edge sensing adapted to the material of the wafer even of the material is transparent or not. A photodiode (27) is provided in a vicinity of the first pixel from the center shaft of the wafer rotation means of a CCD linear sensor (5) to detect a wafer (1) on the basis of the luminous energy value. The time from the issuance of a measurement command to the sensor (5) to that of an ROG signal for transmitting the detection timing of the sensor (5) is measured to correct the angular error of a measurement position due to the rotation during this measurement. For sensing an edge position of the wafer (1), the scan start point of the sensor (5) is set on the opposite side of the center shaft of the wafer rotation means. When the wafer is transparent a sense signal is binarized to set its change point as the edge position.

Abstract: This invention intends to enable it to easily determine that the wafer has come to a predetermined measurement position so that a measurement command is issued to a sensor controller to start measurement.

Abstract: ABSTRACT An absolute encoder is arranged by a first memory 23 for storing thereinto an absolute value signal which is produced by an absolute value signal producing section 6 every constant time period; a second memory 24 for storing thereinto an absolute value signal which has been produced in one-preceding time period with respect to a time period of an absolute value signal entered into the first memory 23; a comparing/calculating section 25 for comparing the absolute value signal stored in the first memory 23 with the absolute value signal which has been produced in the one-preceding time period and has been stored in the second memory 24 so as to calculate an increase/decrease amount; a dividing process section 26 for dividing the increase/decrease amount in an equal rate within a producing time period of the absolute value signal; and an interpolated absolute value signal producing section 27 for reading the absolute value signal which has been produced in the one-preceding time period, and thereafter,

Abstract: A wafer prealignment apparatus comprising a CCD linear sensor and a wafer prealignment method which facilitate the sensing of wafer presence, improvement in precision of position sensing, and edge sensing adapted to the material of the wafer even of the material is transparent or not. A photodiode (27) is provided in a vicinity of the first pixel from the center shaft of the wafer rotation means of a CCD linear sensor (5) to detect a wafer (1) on the basis of the luminous energy value. The time from the issuance of a measurement command to the sensor (5) to that of an ROG signal for transmitting the detection timing of the sensor (5) is measured to correct the angular error of a measurement position due to the rotation during this measurement. For sensing an edge position of the wafer (1), the scan start point of the sensor (5) is set on the opposite side of the center shaft of the wafer rotation means. When the wafer is transparent a sense signal is binarized to set its change point as the edge position.

Abstract: An absolute encoder that can generate an absolute value signal by performing simple operation processing.