Effects of a small exit pupil in an optical configuration for virtual reality

摘要

In the optical part of a virtual reality system often an exit pupil is used that is larger than the entrance pupil of the eye. However, a system with a small exit pupil could have several advantages: more efficient use of light, less accommodation/convergence conflict, better optical quality, and a larger angular image field. To see under which conditions one can benefit from these advantages, we examine two possible drawbacks of using a small exit pupil, one related to the loss in image quality at exit pupil decentration and the other related to the limitations in the freedom of movement of the eye. An optical system with a small exit pupil, preferably a little larger than 1 mm in diameter, is only feasible, if a combination of eye-tracker and exit pupil shifting mechanism is implemented.