A head up display system for a vehicle that includes a compact image
source for projecting an image. The compact image source may be foldable
up toward or into a cockpit ceiling of the vehicle, be positioned within
a dashboard of the vehicle, or located at another suitable position. A
combiner reflects the projected image with optical power toward an
observer for observation. The combiner is positioned so that the
observer, in a line of sight, may see a visual exterior view of an
outside scene through the combiner and the projected image in the
combiner. In a preferred embodiment, the image source includes an
illumination system that includes a high power light emitting diode (LED)
array assembly. A Fresnel lens array is operatively associated with the
LED array assembly for receiving light produced by the LED and providing
a nearly collimated light output. A spatial light modulator receives the
nearly collimated light output. The preferred combiner is a meniscus
combiner that includes a meniscus lens; a multi-layer dichroic coating
formed on a first surface of the meniscus lens; and, an anti-reflection
coating formed on a second, opposite surface of the meniscus lens. The
meniscus combiner preferably utilizes a non-symmetric aspheric meniscus
lens.