| 摘要 |
A device for continually measuring the displacement of an object utilizing a laser beam. A photoreceiver is attached to the object in such a manner as to be subject to displacement corresponding to the displacement of the object. The photoreceiver has a measuring photoelectric cell extending in the direction in which displacement is being measured. The photoelectric cell has a sensitivity which changes continuously in the direction of measurement. A source of a laser beam is positioned on a reference point, and the beam is directed toward the photocell to generate an electrical signal in response to the position of the beam on the cell. The beam is fanned out along a path which intersects and crosses the cell, and accordingly displacement of the object causes a displacement of the cell which generates a change in the electrical output. In order to produce an electrical output signal which is free from fluctuations due to causes other than the displacement of the object, a comparison photoelectric cell is disposed parallel to the measuring photocell, and the laser beam crosses the comparison cell as well. The comparison cell produces a signal which is fed to an amplifier and which may be used as a reference to compare the magnitude of the output from the measuring photoelectric cell. In addition, the amplifier for the comparison cell may be self adjusting to produce a constant output and may be coupled to the amplifier at the output of the measuring cell to control the amplification factor thereof. In this way, the amplification can be varied without losing the reference as a means for determining the displacement of the measuring cell.
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