Patent ID: 7111944
Filing Date: 2006-09-26
Classification: G03B,H05B,Y02B

Abstract:
1. An image projector comprising: a discharge lamp; a discharge lamp driving circuit, an image reproducer; an image reproducer driving circuit for driving the image reproducer with using an image data outputted from an external apparatus; a projection lens for projecting an image reproduced by the image reproducer on a screen; and a display device for displaying at least information of a condition of the discharge lamp; wherein the discharge lamp driving circuit further comprises: a driving signal generator generating a driving signal applied to the discharge lamp, and executing a feedback control for varying voltage of the driving signal corresponding to variation of a load of the discharge lamp in a manner so that power consumption of the discharge lamp becomes substantially constant; a lamp condition judger sensing a signal corresponding to the voltage or current of the driving signal applied to the discharge lamp, and judging that the discharge lamp has been damaged, the discharge lamp has been normally lighted, the discharge lamp has not been lighted or the life of the discharge lamp reaches to the late stage corresponding to a value of the sensed voltage or the sensed current; and an alarm output unit connected between the lamp condition judger and the display device and outputting an alarm corresponding to at least that the discharge lamp has been damaged, the discharge lamp has not been lighted and the life of the discharge lamp reaches to the late stage based on a result of judgment of the lamp condition judger.