| 摘要 |
PURPOSE:To decide on the unevenness of a measurement surface easily and securely without contacting a sample directly by placing a pattern recognizing member in luminous flux having the coherence decreased and deflecting it by a specific angle, and varying the angle of incidence on an optical member and varying interference fringes. CONSTITUTION:Laser light from a laser oscillator 1 is reflected by a reflecting mirror 3 and incident on an object lens 4. A diffusing plate 6 made of frosted glass is arranged near the focus of the lens 4 to decrease the coherence of the laser light. The luminous flux is reflected by reflecting mirrors 7 and 8 and incident on a wedge primary standard 10 (optical member) through a collimator lens 9. Then, parallel luminous flux incident on an incidence surface 10a is reflected by the reference surface 10b of the standard 10 and the measurement surface 11a of the sample 11. Further, its reflected light is reflected by a reflecting plate 12 and interference fringes formed owing to the optical path difference between the both are read by an image pickup device 13. For the purpose, the pattern recognizing member 17 is placed in the optical path automatically and moved by 0-30 deg. perpendicularly to the optical axis to vary the angle of the parallel luminous flux incident on the standard 10, thereby deciding on a projection and a recess of the measurement surface 11a from variation of the interference fringes A. |
