| 摘要 |
PURPOSE:To enable simple and highly accurate measurement irrespective the size of an object of measurement, by irradiating the measured end portions of the object by two parallel beams of light being reverse in the direction to each other. CONSTITUTION:Parallel beams 10 of light are applied to an object 9 of measurement from the directions reverse to each other so that the respective parts of the parallel beams 10 are intercepted by the measured end portions 9a of the object 9. The areas W2 of the parallel beams 10 intercepted by the object 9 (or the areas thereof not intercepted by the object) are detected to measure the size of the object 9 of measurement. According to this method, the same detecting means (photosensors) 1 can be used irrespective of the size of the object 9 of measurement, and the object 9 can be measured constantly with the same accuracy. |
