HEADS-UP DISPLAY FOR VEHICLE USING HOLOGRAPHIC OPTICAL ELEMENTS

A heads-up display device for a vehicle including a holographic projection optical system constituted by a transmissive holographic optical element and a holographic combiner constituted by a reflective holographic optical element, capable of reducing the number of constituting elements thereof and, thus, the total volume thereof. With the reduced volume, the holographic projection optical system is rotatable totally by use of a drive motor. By virtue of the rotatable construction of the holographic projection optical system, a driver can adjust properly the position of a reflected image indicative of various information projected onto the windshield of the vehicle, depending on the position of his eyes. A position sensor is provided for sensing the rotation of the holographic projection optical system beyond a predetermined range corresponding to a variation range of the position of driver's eyes. When the position sensor senses the rotation of the holographic projection optical system beyond the predetermined range, a power cut-off element cuts off the drive power from the drive motor transmitted to the holographic projection optical system. Since various information can be displayed on the windshield of the vehicle, the driver can drive the vehicle safely in a convenient and comfortable state.