| 摘要 |
PURPOSE:To facilitate the setting of a displacement meter to the register in a detection head having high dissolving power and to enable automatic measurement, by together providing a minute displacement meter having a wide measuring range in coaxial relation to a minute displacement having high resolving power and simultaneously measuring the same measuring point by a plurality of minute displacement meters. CONSTITUTION:The reflected beam from a specimen 6 is guided to the outside by the polarizing beam splitter 3 of a minute displacement meter and a beam splitter 30 is provided between the splitter 3 and a beam splitter 7. A part of the reflected beam from the specimen 6 through the splitter 30 is incident to a quartering photosensor 23 from a cylindrical lens 21 to form an image thereon and the focus error signal from the sensor 23 is processed by a differential amplifier 33 and a compensation circuit 34 to control a stage driving motor 37. The reflected beams divided by the splitter 7 are respectively applied to critical angle prisms 8, 9 and the signals thereof are applied to bisecting photosensors 31, 32. The signals from said sensors 31, 32 are processed by differential amplifier systems 38, 39 and an adder circuit 40 and applied to a displacement sensor 44 through a displacement output apparatus 40.
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