Patent ID: 9618751
Date: 2017-04-11
CPC Classifications: G02B

Claim:
1. A head-mounted or helmet-mounted display apparatus comprising: an optical element which in use is disposed in front of the eyes of a user, the optical element comprises a waveguide portion, the waveguide portion which in use is also disposed in front of the eyes of the user; a light source of image-bearing light; an input element configured to input the image-bearing light to the waveguide portion; a first diffraction means for propagation of image-bearing light of the light source through the waveguide portion, the first diffraction means being arranged to release the image bearing light from the waveguide portion, the waveguide portion having optical powers such that the released light provides a first visible image to one of the user's eyes; a second diffraction means for propagation of image-bearing light of the light source through the waveguide portion, the second diffraction means being arranged to release the image bearing light from the waveguide portion, the waveguide portion having optical powers such that the released light provides a second visible image to the other of the user's eyes, the waveguide portion including the first diffraction means and the second diffraction means; and a switching means for switching the image-bearing light repeatedly between the first diffraction means and the second diffraction means whereby to provide the first visible image or the second visible image to a respective eye of a user.