| 摘要 |
PURPOSE:To shorten the down time of an apparatus, by holding the history data of fluctuation in characteristics of an optical projecting system even if an unexpected state such as power failure occurs, and correcting the data after the power is recovered. CONSTITUTION:When the normal projection of objects is interrupted by, e.g., power outage, predicted data for the fluctuation in characteristics of images at the time of interruption are stored in a memory Q4 by a battery backup part Q6. A timer Q5 starts counting. When a power source is recovered, a time required for the recovery is inputted into a CPU Q1 from the timer Q5. The stored data in the memory Q4 is also inputted into the CPU Q1. In the CPU Q1, the correct predicted data of the fluctuation of the image forming characteristics in the optical projecting system at the time of the recovery of the power source is obtained based on the inputted data, and the image forming characteristics of the optical projecting system are controlled. Thus the down time of the system is shortened. |
