| 摘要 |
<p>PURPOSE:To measure the position of a surface to be detected irrelevant to the surface shape without contacting by splitting luminous flux into two by using a light source which has short coherence distance, reflecting one piece of the luminous flux by the surface to be detected and passing the other piece through a reference optical system, and superposing the both again on each other and reading interference fringes. CONSTITUTION:Light from a light source 8 is collimated by a collimator 12 into parallel light, which is split into two through a polarization beam splitter 18. One light beam is converged on the object surface of a lens 1 to be detected by adjusting an objective lens 12 and then reflected. The other light beam is reflected by a corner cube 20. The corner cube 20 is movable in the y-direction and the quantity of the movement is measured. Two reflected light beams are superposed on each other and interference fringes are measured. The corner cube 20 is moved and when the output of a photoelectric element 33 peaks, the two split light beams become equal to optical path length.</p> |
