초록 ▼

A head up display includes a simplified holographic combiner which has a low surface spatial frequency for avoiding flare. Symbology generated by a cathode-ray-tube is focused by relay optics and then reflected by a holographic optical element toward the holographic combiner. The last mentioned holo

A head up display includes a simplified holographic combiner which has a low surface spatial frequency for avoiding flare. Symbology generated by a cathode-ray-tube is focused by relay optics and then reflected by a holographic optical element toward the holographic combiner. The last mentioned holographic optical element is provided with optical power in part compensating for distortions attributable to the large off-axis angle at which the holographic combiner is operated.

대표청구항 ▼

A system for providing an essentially flare-free head up display, comprising: a first holographic optical element functioning as a combiner through which an exterior view may be seen by an observer, a visual information source, lens means for forming an intermediate image of said information source,

A system for providing an essentially flare-free head up display, comprising: a first holographic optical element functioning as a combiner through which an exterior view may be seen by an observer, a visual information source, lens means for forming an intermediate image of said information source, and a second holographic optical element located out of the observer\s direct line of sight and positioned for reflecting the light which forms said intermediate image toward said first holographic optical element at an off-axis angle relative to said first holographic optical element to permit further imaging of said intermediate image at infinity by said first holographic optical element, said second holographic optical element having optical aberrating properties of a reverse sense to those of the first holographic optical element for compensating aberrating properties of said first holographic optical element causing said first holographic optical element to provide a high quality virtual image at infinity in response to said intermediate image, said first holographic optical element having a curved shape and a surface spatial frequency of approximately two or fewer line pairs per millimeter for reducing flare from bright objects viewed through said first holographic optical element.