| 摘要 |
PURPOSE:To detect a resistance on a surface when a panel is broken so as to inhibit an output of a high voltage by grounding a part of the end portion of a transparent film to a ground, and connecting a part of the other end portion to a logic power source via a resistance. CONSTITUTION:On a display surface of a panel 1, there is provided a conductive transparent film, on one side of the left end of which is grounded by the use of metal electrodes 2. A part of the end portion of the transparent film is connected to a logic power source via a resistance R2. There are further provided a surface resistance RP of the transparent film and a resistance R3 having a resistance value slightly higher than the resistance RP. Accordingly, since a differential input voltage of a comparator 3 becomes a value relating to a voltage VCC of the logic power source, it is normally plus so that an output is also plus, thus leading to operation of a high voltage power source 4. When the panel 1 is broken, the resistance RP is increased. As a result, the differential input voltage of the comparator 3 becomes minus. Consequently, the output of the comparator 3 comes into a low level, thus stopping the output of the high voltage power source 4. |
