| 摘要 |
PURPOSE:To provide a driving circuit by which the ON time of a cathode luminescence type lighting system can be variably adjusted and the life of the system can be kept long. CONSTITUTION:In a lighting system, electrons are released from a Joule heated cathode to an anode and collide with an anode-side phosphor to cause luminescence. In a method for driving the lighting system, the heating time (th) during which the cathode is heated by transmitting power thereto, the ON time (ton) during which power is not transmitted to the cathode but only electron emission is caused to cause luminescence, and a dummy time (td) during which power is not transmitted to the cathode and no luminescence is caused, are repeated in a fixed lighting period (t0). For the variable adjustment of the ON time (ton), the amount of change of the ON time is canceled out by the dummy time (td) so that the heating time (th) is held constant. The ON time (ton) is controlled at a timing independent of that of the heating time (th), and controlling the heating time (th) at timing dependent on that timing facilitates the timing control of the ON time (ton). |
