Patent ID: 8749890
Filing Date: 2014-06-10
Classification: G02B

Abstract:
1. A head up display, comprising: a micro display image source; collimating optics capable of providing a field of view of at least 30 degrees horizontally by 18 degrees vertically; and a combiner, the collimating optics being disposed between the combiner and the image source, the collimating optics providing collimated light associated with the micro display image source, the collimating optics having a compact folded beam path, the combiner receiving the collimated light from the collimating optics at an input and providing the collimated light to an output, the collimating light traveling from the input to the output within the combiner by total internal reflection, wherein an input diffraction grating is disposed in a first area at the input and an output diffraction grating is disposed in a second area at the output, wherein the first area is smaller than the second area by a factor of greater than or equal to 3, wherein the combiner provides pupil expansion in the vertical direction.