| 摘要 |
<p>PURPOSE: To make it possible to easily prevent the access to safety information from the outside by encapsulating a device preventing access to safety information into a piezoelectric material which generates a voltage to destroy the safety information when a force is applied. CONSTITUTION: An electric circuit 21 which can made into the form of, for example, a printed circuit board or semiconductor chip is partially enveloped by an encapsulating body which is a sandwich body consisting of two electrodes 22, 24 holding the piezoelectric material 23. The space between the electric circuit 21 and the sandwich body is filled with a packing material (for example, curable foam). An electric field is generated when such a stress as compressive force is applied on the piezoelectric material 23. Then, the voltage attaining a high voltage is generated when the force is applied on the encapsulating body by, for example, a drill which is placed on the encapsulating body. This voltage is used for triggering a circuit for destroying the information or for directly destroying the information by the voltage itself.</p> |
