Patent ID: 9618750
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 first moveable light source and a second moveable light source of image-bearing light, the first moveable light source and the second moveable light source being configured to move about an axis of symmetry of the optical element; an input element configured to input the image-bearing light to the waveguide portion; and a first diffraction means for propagation of image-bearing light of the first 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 second 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, the first moveable light source and the second moveable light source being disposed such that relative angular movement of the first light source and the second light source about the axis of symmetry of the optical element adjusts the inter-pupillary spacing of the first visible image and the second visible image presented to a respective eye of a user.