Sony Magnescale Inc.

Sony Precision Technology Inc.

Sony Magnescale Incorporation

Takamoto Yoshioka

Akihisa Narimatsu

Tadahiko Shimano

Kiyoshi Himuro

Junichi Tada

Katsutoshi Mibu

The present invention provides a position detection apparatus capable of suppressing a crosstalk between a scale signal and an origin signal and detecting a position with a high accuracy. A recording medium 12 of a round bar shape has a magnetic signal alternately reversing the polarity at a predetermined recording wavelength .lambda..sub.1 and recorded as a scale signal in the longitudinal direction of the recording medium 12. This scale signal is recorded over the entire outer circumferential surface of the recording medium 12 and almost over the entire length of the recording medium 12. Moreover, the recording medium 12 has a one-wavelength origin signal of recording wavelength .lambda..sub.2 recorded at least at one position over the scale signal. The recording wavelength .lambda..sub.2 of this origin signal is longer than the recording wavelength .lambda..sub.1 of the scale signal. The origin signal is recorded at a part of the outer circumference. An origin signal detection head is arranged to face the origin signal whereas a scale signal detection head is arranged opposite to the origin signal detection head so as to sandwich the recording medium 12.

Position detection apparatus

A position detecting apparatus is comprised of a magnetic scale formed by sequentially disposing magnets at a lattice pitch .lambda., and a magnetic sensor disposed in an opposing relation to the magnetic scale so as to become relatively movable to each other, wherein the magnetic sensor includes a plurality of magnetic sensor elements, each having first and second magnetic reluctance elements, the first and second magnetic reluctance elements are spaced apart from each other by 1/6.lambda. in the direction in which the magnets are disposed and connected in series, and the first and second magnetic reluctance elements are disposed so as not to overlap each other as seen from the direction parallel to the direction in which the magnets are disposed.

Position detector with magnetic scale and magnetic sensor that has

A detector head for use in a measuring device includes a plurality of constituent measuring elements arranged in at least two blocks, each block producing an output signal of equal amplitude, and a phase shifter provided to shift the relative phases of the output signals of the blocks to have a predetermined relative phase difference, whereby selected higher-order harmonic components are cancelled from the resultant signal formed by summing the signals produced by the separate blocks of constituent elements.

Detector for use for measuring dimensions of an object

Growing community of inventors

Kanagawa, Japan

Takamoto Yoshioka