| 摘要 |
PURPOSE:To obtain electric heated glass excellent in safety wherein electric power supply to a broken pane of the electric heated glass is avoided by preventing restart of power supply after disconnection due to a glass crack is detected and the power supply is stopped. CONSTITUTION:An electric conductive filament 15 is arranged so as to be in contact with neither an electric heating part 12 nor a power supply bus bar 11. When disconnection of the filament 15 is detected to detect a glass crack, electric power supply is stopped and suspension of the power supply is continued even when the detected part is recovered. Namely, a judgement control resistor RB is set to a value equal to or lower than an operating point voltage of a semi-conductor Q1 when a resistor RA of the electric conductive filament 15 is in a normal state, and thus the Q1 is connected to supply a current to operate a relay RL1 when the RA is disconnected. The operation of the relay RL1 activates a relay RL2 to cut of a power supply source for electric heated glass and continue the supply suspension. Accordingly, power supply to a broken pane of the electric heated glass 10 is avoided. |
