A monolithic optical element for an eyepiece in a head mounted display
system has a body, in which a first surface of the body receives light
from a display device, the light passes through a second surface of the
body to an eye of a user, and a reflective folding surface is located
optically between the first surface and the second surface. The
reflective folding surface folds an optical path between the first
surface and the second surface. Finally, a diffractive optical element is
provided on at least one of the first surface or the second surface. The
use of the diffractive optical surface enables the eyepiece element to be
constructed of a single optical substrate material, yet function over a
broad color spectrum with superior resolution and minimal distortion over
a large field of view.