Patent ID: 8368341

Claim:
A head up display device for a vehicle, comprising: a display configured to display a light-emitting image; an optical system that includes a reflecting mirror, which is disposed rotatably relative to the display to reflect the image displayed by the display, and that is configured to project the image reflected on the reflecting mirror onto a projection member of the vehicle and to thereby display a virtual image of vehicle-related information on the projection member; a stepping motor configured to rotate the reflecting mirror as a result of application of a drive signal to the stepping motor and thereby to adjust a display position of the virtual image, wherein: the drive signal has an amplitude in accordance with an electrical angle; and a stabilizing point of the stepping motor appears at every predetermined electrical angle in accordance with detent torque of the stepping motor; and a control system configured to control the drive signal such that the electrical angle changes in accordance with an adjustment command from an outside, the control system including: a determining means for determining whether the adjustment command for micro-step control is given or not, wherein through the micro-step control, the drive signal is controlled such that the electrical angle changes by a set angle each time, the set angle being smaller than a stabilizing point interval; a micro-step control means for performing the micro-step control as long as the determining means determines that the adjustment command for the micro-step control is given; and a forcible control means for forcibly controlling the drive signal such that the electrical angle changes to the stabilizing point, wherein when determination made by the determining means whether the adjustment command for the micro-step control is given or not switches from determination that the adjustment command is given to determination that the adjustment command is not given, the forcible control means forcibly controls the drive signal, provided that the electrical angle as of a time of the determination that the adjustment command is not given is shifted from the stabilizing point.