| 摘要 |
PROBLEM TO BE SOLVED: To provide a projector device capable of detecting the position of a projection lens and detecting the driving range end of the projection lens without using a linear sensor and a microswitch.SOLUTION: The projector includes: a DC motor 201 for driving the projection lens; and a back electromotive force detection circuit 202 for detecting the number of rotations based on the back electromotive force generated from the DC motor 201; wherein the driving range end of the projection lens is detected by comparing the number of rotations when the projection lens is normally driven and the number of rotations when the projection lens reaches the driving range end, and also, the position of the projection lens is detected by counting the number of rotations from the end. |
