HEAD MOUNTED DISPLAY

• US 20150062707A1
• Filed: 08/25/2014
• Published: 03/05/2015
• Est. Priority Date: 04/29/2009
• Status: Active Grant

• Current Assignee: Snap, Inc.
• Original Assignee: BAE Systems Plc
• Inventors: SIMMONDS, Michael David, VALERA, Mohmed Salim
• Granted Patent: US 9,618,750 B2
• Time in Patent Office: Days
• US Class Current: 359/567
• CPC Class Codes: G02B 2027/0123 comprising devices increasing the field of view
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/4205 having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant
• CPC Class Codes: G02B 27/4272 having plural diffractive elements positioned sequentially along the optical path
• CPC Class Codes: G02B 27/44 Grating systems; Zone plate systems G02B27/46 takes precedence
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements

Abstract

A head-mounted or helmet-mounted display apparatus is provided. The apparatus includes an optical element which in use is disposed in front of the eyes of a user. The optical element comprises a waveguide portion. The apparatus further includes a first light source and a second light source of image-bearing light. The apparatus further includes first diffraction element for propagation of image-bearing light of the first light source through the optical element. The apparatus further includes a second diffraction element for propagation of image-bearing light of the second light source through the optical element. The first light source and the second light source is disposed such that relative angular movement of the first light source and the second light source about an axis of symmetry of the optical element adjusts the inter-pupillary spacing of a first visible image and a second visible image presented to a respective eye of a user.

Claims

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;

a first light source and a second light source of image-bearing light; and

a first diffraction means for propagation of image-bearing light of the first light source through the optical element, the first diffraction means being arranged to release the image bearing light from the optical element, the optical element and the first diffraction means 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 optical element, the second diffraction means being arranged to release the image bearing light from the optical element, the optical element and the second diffraction means having optical powers such that the released light provides a second visible image to the other of the user'"'"'s eyes, the first light source and the second light source being disposed such that relative angular movement of the first light source and the second light source about an 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.

2. The apparatus of claim 1, wherein the optical element is curved in both azimuth and elevation relative to the eyes of a user.

3. The apparatus of claim 2, wherein each of the first diffraction means and the second diffraction means include grating lines including a curved diffractive component arranged to converge the image-bearing light exiting the optical element.

4. The apparatus of claim 3, wherein each of the first diffraction means and the second diffraction means includes an input diffractive element and an output diffractive element.

5. The apparatus of claim 4, wherein at least the output diffractive element has spherical optical power in azimuth and elevation relative to the eyes of a user.

6. The apparatus of claim 5, wherein spherical optical power is provided by non-parallel diffractive features of the output diffractive element.

7. The apparatus of claim 4, wherein the output diffractive element has an angular bandwidth which is less than the angular field of view of the first visible image or the second visible image which is provided to a respective eye, the angle of diffraction of the output diffractive element varying across the element so as to present the first visible image or the second visible image to the respective eye.

8. The apparatus of claim 2, wherein an optical axis of a waveguide formed within the optical element lies in a plane containing a sagittal axis of symmetry of the optical element and the eyes of the user.

9. The apparatus of claim 1, wherein the first light source and the second light source comprise a display panel and means for illuminating it, or a self-illuminating display panel.