INTERNAL INSPECTION METHOD AND INSTRUMENT FOR SPECIMEN USING ULTRASONIC WAVE

摘要

PURPOSE: To expand the range wherein two kinds of detected foreign matters possible to exist inside can be discriminated one from another. CONSTITUTION: Wedge-shaped bodies 1c and 1c are provided to tilt a transmitting probe 1a and receiving probe 1b to a subject 2 to be inspected by a desired angle. (p) represents an incident wave on the surface of a foreign matter (x), and (q) the reflected wave from the surface of the foreign matter. The phase in a section giving an angle at which reflection factor is 0 and a critical angle, is grasped beforehand by an experiment or a logic calculation to tilt the probes by such an angle as to give the reflection facor of 0 and the critical angle in the phase. As the angle and the critical angle at which the reflection factor is zero vary with materials composing the subject and foreign matter, the angles are known beforehand according to a specified object to be inspected and an ultrasonic wave is admitted at an angle within a range as expected. The reflected wave thus obtained is used to judge whether the foreign matter (x) as cause of generating the reflected wave is a forecast specified foreign matter or not.