Abstract: A head up display system having a diffusing image plane or diffuser. The light output of a relatively small image source is imaged on the diffuser by way of imaging optics. A mirror is used to image light from the diffuser onto a windshield and correct for distortion caused by the windshield. The diffuser is advantageously used when a large field-of-view is desired, or sun load characteristics need to be addressed. The diffuser may be flat or curved in order to optimize the system for different applications. The magnification of the mirror may be made relatively low, and the solar energy density that is made incident on the image source is reduced, providing for a low cost, high performance, color head up display system.

Abstract: An FET switch and an inductor in series with a DC motor supply voltage pulses at a high frequency, a power diode permits current recirculation, and a capacitor connected to the motor maintains a mean DC voltage level on the motor which is proportional to the switching duty cycle. The motor speed is proportional to the mean voltage. Smoothing due to the capacitor and the inductor converts the voltage pulses due to switching to a small sinusoidal ripple to attain low radiated emissions.