Head-up display device for vehicle

Patent metadata

Field	Value
Publication number	US-8970933-B2
Application number	US-201313756949-A
Country	US
Kind code	B2
Filing date	Feb 1, 2013
Priority date	Feb 3, 2012
Publication date	Mar 3, 2015
Grant date	Mar 3, 2015

Abstract

A HUD device includes a stepper motor, which rotates a reflection mirror for adjusting a display position of a virtual image. The stepper motor has an electric stabilization point and a mechanical stabilization point. A control system controls a drive signal for the stepper motor to change by a step angle at every predetermined period Ts in response to an adjustment instruction inputted from an adjustment switch. The control system continues to apply the drive signal until the electric stabilization point is attained even after the adjustment instruction is stopped to operate the stepper motor in a powered rotation mode. The stepper motor then operates in an inertia rotation mode toward the mechanical stabilization point is attained.

First claim

What is claimed is:

1. A head-up display device for a vehicle comprising:
a display unit for displaying a light-emitted image;
an optical system including a reflection mirror, which is provided rotatably to reflect the light-emitted image and project a reflected image toward a projection target so that a virtual image of vehicle related information is displayed;
a stepper motor for driving, when powered by a drive signal, the reflection mirror to rotate for adjusting a display position of the virtual image, the stepper motor having plural electric stabilization points, at which a motor operation is electrically stabilized by a holding torque generated when powered, and plural mechanical stabilization points, at which the motor operation is stabilized by a detent torque generated when not powered;
a control system for controlling the drive signal for the stepper motor in response to an adjustment instruction inputted from an external side,
wherein the stepper motor is configured to have a powered rotation mode and an inertia rotation mode,
wherein, in the powered rotation mode, the control system is configured to continue to apply the drive signal even after the adjustment instruction is stopped until the electric stabilization point is attained, so that the stepper motor performs powered rotation, and immediately stop applying the drive signal when the electric stabilization point is attained,
wherein, in the inertia rotation mode, the stepper motor performs inertia rotation toward the mechanical stabilization point after the powered rotation mode; and
wherein the stepper motor has phase coils, to which electric power is supplied by the drive signal to electrically stabilize the stepper motor by the holding torque at the electric stabilization points in the powered rotation mode and no electric power is supplied to mechanically stabilize the stepper motor by the detent torque at the mechanical stabilization points during the inertia rotation.

2. The head-up display device for a vehicle according to claim 1 , wherein:
the control system is configured to change an electric angle of the drive signal applied to the stepper motor by a step angle at every predetermined time period while application of the adjustment instruction is continued, the step angle being smaller than an interval between two electric stabilization points; and
the control system is configured to stop application of the stepper motor after continuing the application of the drive signal for the predetermined time period when an electric angle, which is one step angle before the electric stabilization point, in the powered rotation mode, which is after the application of the adjustment instruction is stopped.

3. The head-up display device for a vehicle according to claim 2 , wherein:
the step angle is predetermined to be 90/N with N being greater than 2.

4. The head-up display device for a vehicle according to claim 1 , wherein:
the control system is configured to check whether a present electric angle of the stepper motor is at the electric stabilization point after the adjustment instruction is stopped.

5. The head-up display device for a vehicle according to claim 1 , wherein the electrical stabilization point and the mechanical stabilization point are different in phase.

6. The head-up display device for a vehicle according to claim 1 , wherein the control system does not apply the drive signal in the inertia rotation mode.

Assignees

• Denso Corp

Inventors

• Sasaki Tatsuya
• Nakane Hideyuki

Classifications

• B60L1/003

  to auxiliary motors, e.g. for pumps, compressors · CPC title

• B60L2250/16

  by display · CPC title

• G02B2027/0154

  with movable elements · CPC title

• Y02T10/641

  Cross-Sectional Technologies · mapped topic

• H02P8/22

  Control of step size; Intermediate stepping, e.g. microstepping · CPC title