| 摘要 |
PURPOSE:To eliminate an error by extracting only a steep pulselike defective detection signal by performing irradiation with two kinds of different-wavelength laser beams at a fine interval, and then removing a noise due to slight unevenness by finding a difference between their scattered light signals. CONSTITUTION:A blue laser beam 6 and a red laser beam 7 are illuminated a half-mirror 8 at right angles to each other, and thus the surface of a sample 9 is irradiated with both the beams in parallel at an interval of several mum. Light scattered by the surface of the sample 9 is guided into an integral ball 10 and then passed through a red filter 11 and a blue filter 12 to separate the scattered reflection light, which is converted photoelectrically converted by photomultipliers 13 and 14. Those two signals are inputted to a differential amplifier 15 to eliminate a noise signal due to unevenness and consequently only a defective signal remains, thus improving detection precision. |
