| 摘要 |
An aim of this invention is to detect an unusual state when a thief or burglar breaks the glass plate of a glass window to attempt to enter a building, and to issue an alarm or make it possible to notify a security company. According to one aspect of this invention, a conductive pattern 50 of predetermined shape is formed by a conductive thin layer on the surface of a glass plate 47 of a window glass 45 , and a detector 51 is connected to the split or cut positions of this conductive pattern 50 . If the glass plate 47 is broken so that the conductive pattern 50 open, the detector 51 detects the open circuit of the conductive pattern, the detector 51 issues an alarm, transmits a damage detection signal to a relay 74 by radio, and transmits the damage detection signal from this relay 74 to a central monitoring unit 84.
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