SOUND VELOCITY MEASURING METHOD IN INSULATING SOLID AND SOUND VELOCITY MEASURING DEVICE

摘要

PURPOSE: To enable highly accurate measurement whose operation is easy and which is hardly influenced by a temperature or humidity by performing operation from a difference or the like in reaching time to a piezoelectric element of a wave passing through an insulating solid and an unpassed wave of an electric oscillatory wave. ;CONSTITUTION: An insulating solid 2 is sandwiched by electrodes 5 and 6, and pulse voltage is impressed while impressing DC voltage from the electrode 5 side. Then, electric charge induced to a solid 2 surface vibrates, and an oscillatory wave is generated. At this time, an oscillatory wave (oscillatory wave A) generated on a surface where the solid 2 contacts with the electrode 5 passes through the solid 2 and the electrode 6, and reaches a piezoelectric element 7. On the other hand, an oscillatory wave (oscillatory wave B) generated on a surface where the solid 2 contacts with the electrode 6 passes through only the electrode 6, and reaches the element 7. Thereby, since the oscillatory wave A reaches the element 7 later than the oscillatory wave B, a detector 9 detects the appearing time and appearance of the two peaks different in codes, and finds a difference in the appearing time from these. Then, sound velocity in the solid 2 can be found from a difference in a thickness of the solid 2/the peak detecting time.;COPYRIGHT: (C)1995,JPO