Holographic Combiners for Head-Up Displays.

摘要

The use of holographic optical elements as combiners in Head-Up Displays (HUD) offers performance improvements in two respects; because the holographic combiner has a high reflectivity over a narrow spectral region, it can make more efficient use of the light, and by forming the final element of the collimating lens, it can increase the field-of-view. Both improvements were examined separately in an analytical and experimental investigation directed at evaluating holographic combiners in existing HUD systems. Flat holographic combiners that can be substituted on a one-for-one replacement basis for the conventional combiner in an existing HUD were designed and fabricated. The combiners were fabricated in dichromated gelatin, and were characterized by diffraction efficiencies in excess of 90% and angular bandwidths of 10 to 12 deg. A computer analysis of curved holographic combiners in the A-10 HUD generated a design that shows promise for increasing the instantaneous field-of-view to 15 deg and the total field-of-view to 20 deg.