| 摘要 |
<p>In order to electrically detect the presence or absence of a pinhole or a crack on a package (1) in which a conductive content is sealed by an insulating material, the package (1) is disposed at suitable gaps between a pair of electrodes (2, 3). There is applied across the electrodes (2, 3) a voltage of such a range that a corona discharge occurs when no pinhole nor crack is present on the package (1) and a flash occurs when a pinhole or a crack is present on the package (1). An electric current containing a high frequency component will flow in both cases. The frequency band of the high frequency component is in the regions of several tens of kHz when the corona discharge occurs (see fig. 4(a)) while it is in the region of several kHz when the flash occurs (see fig. 4(b)). Therefore, the presence or absence of the pinhole or crack maz be detected by observing the frequency component of the current.</p> |
