Patent ID: 6559955
Filing Date: 2003-05-06
Classification: G01B

Abstract:
A straightness measuring apparatus for a rectilinearly moving body, comprising:a horizontal, parallel two-surface mirror positioned in a horizontal plane and including two reflection mirrors whose reflection surfaces face each other and are spaced by a distance (2)d; a vertical, parallel two-surface mirror positioned in a vertical plane and including two reflection mirrors whose reflection surfaces face each other and are spaced by a distance (2)d; a light source for generating a laser beam; semi-transparent mirrors for splitting the laser beam into two laser beams; optical path changing reflection mirrors for changing a direction of each laser beam; and position sensors for detecting positions of the laser beam reflected from said horizontal, parallel two-surface mirror and said vertical, parallel two-surface mirror, wherein a direction of said horizontal, parallel two-surface mirror is set so that directions of each normal to a bottom surface of each reflection surface take respectively: [Expression 1]mH1=(âˆ’1/(2), 0, 1/(2)), mH2=(1/(2), 0, 1/(2)) or mâ€²H1 (1/(2), 0, âˆ’1/(2), mâ€²H2 (âˆ’1/(2), 0, âˆ’1/(2)) a direction of said vertical parallel two-surface mirror is set so that directions of each normal to a bottom surface of each reflection surface take respectively:[Expression 2]mV1=(0, 1/(2), âˆ’1/(2)), mV2=(0, âˆ’1/(2), 1/(2)) or mâ€²V1=(0, 1/(2), 1/(2)), mâ€²V2=(0, âˆ’1/(2), âˆ’1/(2)) and said light source, said semi-transparent mirrors, said optical path changing reflection mirrors and said position sensors are fixed to positions outside of the rectilinearly moving body.