| 摘要 |
PROBLEM TO BE SOLVED: To provide a substrate capable of simply inspecting its service life. SOLUTION: This substrate is characterized by having an element whose output signal is changed according to the time during which a current is supplied and the operation environment temperature, a detection part for detecting an output signal of the element, and a circuit for supplying the element with the current while the substrate is operated. Hereby, even if the operation time or the operation environment of the substrate is unknown, the service life of the substrate can be estimated, to thereby enable recycle of the substrate. COPYRIGHT: (C)2003,JPO
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