Abstract: An improved head up display utilizes a prism to direct the image of a display CRT upward to a semi-transparent combiner element, permitting a substantially smaller vertical profile of the overall structure. An image is presented to a viewer that appears to be at infinity and is indistinguishable from the exterior scene as viewed from that vantage point. In alternative embodiments, the display unit can utilize more than one prism with one or more combiner elements to increase the vertical height of the viewed image of the CRT while dramatically reducing the vertical space required for the display unit in an instrument panel.

Abstract: A field sequential color head-up display system includes image generating means including a source of light of at least two different wavelengths. A color selective polarizing filter having first and second absorption axes, enables the passage of linearly polarized light of first and second colors. Optical retardation imposed by variable optical retarding means determines the color of the light transmitted by circular polarizing means. Image collimating means apply a generated image of selected colors to an image combiner placed in the line of sight between an observer and a scene, thereby superimposing a generated image over the scene visible to the observer. Holographic elements tuned to the selected wavelengths improve reflection of those wavelengths to the observer.