| 摘要 |
The device is provided for the high-precision dimensional measurement and the control of the absence of exceeding of tolerances of a prescribed value either for a dimension or for the displacement of an object. It comprises a light source (1) and at least one pair of photodetectors (21, 22) illuminated through two windows (31, 32) of surface area which can be varied in opposition. The windows are formed by a diaphragm (4) and a moving mask (3) which is thinner than the aperture of the diaphragm. In order to exploit the difference in illumination of the two photodetectors and to draw from this information the desired measurement, these photodetectors (21, 22) have a common electrode (34) and are connected in series between two electrical supply lines (21, 22). The device makes it possible to measure small dimensions of the order of 1 micron and less. <IMAGE>
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