| 摘要 |
PURPOSE:To increase the measurement range of a substantial thickness of an object to be measured, by a method wherein a correction is made based on a reference plate with an arbitrary thickness serving as a reference point. CONSTITUTION:When a correction takes place by depressing a correction instruction switch 9 of a thickness gauge, a reference plate 10 is driven and drawn out to an irradiation region of radiant rays 4. Then, a certain plate thickness, i.e., a reference plate thickness Tr, serves as a reference, a computation of a plate thickness is made as shown in a formula, where mu is a constant. If an output (reference voltage) Vr of a detector to the reference plate thickness Tr is previously measured and stored, a comparision with an object to be measured can be made. This causes a measurement range to be shifted in a direction of a reference plate and permits the increase in a measurement range of a substantial thickness of the object to be measured. |
