Planar diffractive relay

An optical system for directing image light to a viewer's eye comprising:

• a planar diffractive relay mounted on a helmet having a substantially planar body section, terminated at input and output ends, through which image light is directed,
• a pair of opposing first and second reflective surfaces located, respectively, at the input and output ends, and each angled relative to the planar body section for (a) directing the image light entering the planar body section at the input end along an optical path within the planar body section, and (b) redirecting the image light within the planar body section at the output end along an optical output path directed toward the viewer's eye, and
• each reflective surface having (a) an angular value relative to the planar body section of at least half a critical angle for producing substantially total internal reflection within the planar body section, and (b) a length dimension sufficiently large for preventing the image light from striking each reflective surface more than once,
• wherein an intermediate image is formed within the planar body section, and
• the intermediate image is substantially perpendicular to the planar body section.

An optical system for directing image light to a viewer's eye comprising:

• a planar diffractive relay mounted on a helmet having a substantially planar body section, terminated in a pair of opposing first and second tilted surfaces, each tilted surface angled relative to the planar body section for (a) directing the image light entering the planar body section adjacently to the first tilted surface along an optical path within the planar body section, and (b) redirecting the image light within the planar body section adjacently to the second tilted surface along an optical output path directed toward the viewer's eye,
• each tilted surface having an angular value relative to the planar body section of at least half a critical angle for producing substantially total internal reflection within the planar body section,
• a first DOE formed on the first tilted surface for converging the image light directed along the optical path within the planar body section, and
• a second DOE formed on the second tilted surface for collimating the image light redirected along the optical output path toward the viewer's eye,
• wherein an intermediate image is formed within the planar body section, and
• the intermediate image is substantially perpendicular to the planar body section.