| 摘要 |
PURPOSE:To measure the size of an object to be measured with less error by arranging plural charge coupling elements at the positions shifted so that respective straight photosensitive areas are continued in the measuring length direction of the object to be measured and irradiating parallel luminous flux from plural directions. CONSTITUTION:A photodetecting part 4 is fixed at its bottom on the positions shifted so that the same CCDs 1, 2 having the straight photosensitive areas at two positions of one plane are arranged in parallel. In the measuring length direction of the object 3 to be measured, unsensitive areas 1a, 2b of the CCDs 1, 2 are arranged so as to be covered with a part of the photosensitive area 2a and a part of the photosensitive area 1a respectively. The parallel luminous flux phi1, phi2 irradiated in the directions of respective photosensitive areas 1a, 2a of the CCDs 1, 2 are parallel with each other when observing from the projecting direction of the measuring length of the object 3 to be measured, and then crossed at a measuring point with theta angle. The diameter L of the object 3 to be measured is found out from an equation L=l3-l4-l5. |
