| 摘要 |
PROBLEM TO BE SOLVED: To provide a means to secure safety by promptly cutting off a power source even when a PDP(plasma display panel) is damaged by overturning, etc. SOLUTION: A piezoelectric sensor 1 is mounted to connect with a discharge cell of PDP opened to a PDP. An electric signal from pressure sensor 1 showing a gas pressure in PDP is amplified by an amplifier 2, and the pressure signal S1 is compared with a constant comparison voltage S2 generated by a comparison voltage generation circuit 4 by a comparison circuit 3. This comparison voltage S2 is made to be a middle value between a value corresponding to a normal pressure of PDP and a value corresponding to the atmospheric pressure. Since the normal pressure of PDP is lower than the atmospheric pressure, the pressure signal S1 rises up to a value corresponding to the atmospheric pressure when PDP is damaged by overturning, etc. The comparison circuit 3 outputs a damage signal S3 when the pressure signal S is higher than the comparison voltage S2. This damage signal S3 drives a control circuit 5 for controlling a power source 6 of PDP to cut off the power source 6 of PDP. |
