Head-Mounted Display with Volume Substrate-Guided Holographic Continuous Lens Optics
This application relates to a see-through head-mounted display using recorded substrate-guided holographic continuous lens (SGHCL) and a microdisplay with laser illumination. The high diffraction efficiency of the volume SGHCL creates very high luminance of the virtual image.
1 . A holographic substrate-guided head-mounted see-through display comprising:
(a) an image source comprising a scanning laser beam or a microdisplay with laser illumination;
(b) an edge-illuminated transparent substrate, and;
(c) a single volume substrate-guided holographic continuous lens (SGHCL).
2 . The holographic substrate-guided head-mounted see-through display of claim 1 wherein:
(a) the image source comprises a microdisplay with laser-based illumination;
(b) the edge-illuminated transparent substrate comprises an angled edge or an index-matched transparent prism, and;
(c) the single volume SGHCL comprises a reflection SGHCL, which is index-matched to the substrate, and which is rotated 180° around a perpendicular axis of symmetry passing through the center of the SGHCL;
wherein upon playback, an incident guided beam experiences total internal reflection and hits the SGHCL at Bragg condition.
3 . The holographic substrate-guided head-mounted display of claim 1 wherein the substrate comprises a thickness of about 3-6 mm.
4 . The holographic substrate-guided head-mounted display of claim 2 wherein the substrate and the prism each comprise glass, quartz, acrylic plastic, polycarbonate plastic, or a mixture thereof.
5 . The holographic substrate-guided head-mounted display of claim 1 wherein the substrate comprises a single plate or multiple plates.
6 . The holographic substrate-guided head-mounted display of claim 1 wherein the substrate comprises a 15°-25° angled edge or a 15°-25° index-matched prism.
7 . The holographic substrate-guided head-mounted display of claim 1 wherein the microdisplay comprises a laser-illuminated monochrome or an RGB (full color) liquid crystal on silicon (LCOS), digital light processing (DLP), or liquid crystal display (LCD).
8 . The holographic substrate-guided head-mounted display of claim 1 wherein a side of the substrate, opposite to an eye of the viewer, comprises an anti-reflective coating.
9 . The holographic substrate-guided head-mounted display of claim 1 wherein the substrate comprises a curved shape.
10 . The holographic substrate-guided head-mounted display of claim 1 wherein the substrate comprises prescription glasses.
11 . The holographic substrate-guided head-mounted display of claim 1 wherein the substrate comprises a unitary body or a plurality of bodies made of the same material or different materials.
12 . The holographic substrate-guided head-mounted display of claim 1 wherein one or more edges of the substrate comprise a light absorptive coating.
13 . The holographic substrate-guided head-mounted display of claim 1 wherein the microdisplay is directly attached to the substrate or comprises a gap relative to the substrate.
14 . The holographic substrate-guided head-mounted display of claim 1 wherein the SGHCL comprises a first side and a second side opposite to the first side; and wherein, upon playback, the SGHCL has a diffracted beam on the first side and has a playback beam on the second side.
15 . The holographic substrate-guided head-mounted display of claim 1 wherein, upon playback, the SGHCL has a diffracted beam and a playback beam on a same side.
16 . The holographic substrate-guided head-mounted display of claim 1 wherein the substrate comprises a shape including rectangular, oval, circular, tear-drop, hexagon, rectangular with rounded corners, square, or a mixture thereof.
17 . The holographic substrate-guided head-mounted display of claim 1 wherein a retrieved image comprises a monochrome or RGB (full-color) image.
18 . The holographic substrate-guided head-mounted display of claim 1 comprising a focused, modulated, scanning laser beam and a diffuser.
19 . A method of recording a volume reflection SGHCL comprising shining two beams onto a holographic polymer index-matched to a substrate, wherein a first recording beam is guided from an edge of the substrate and convergent to a first focus point and a second recording beam is a divergent beam, and wherein both beams cover the holographic polymer.
20 . The method of recording the volume reflection SGHCL of claim 19 wherein the substrate is index-matched to a first rectangular block having an angled edge or an index-matched prism;
wherein a first recording beam is guided and convergent with focus in a recording point 01 using a long focus lens and a second recording beam is divergent with focus 02 , in a plane created by a high numerical aperture lens;
wherein a second rectangular block is placed underneath the holographic polymer to avoid total internal reflection of a guided beam back from a bottom surface of the holographic polymer to avoid recording unwanted transmission SGHCL;
wherein the recording convergent beam comprises angles with the substrate and holographic polymer less than or equal to about 48°;
wherein a reliable guided angle is greater than about 12°;
wherein a microdisplay or focused laser beams are positioned at equivalent focus of the recording convergent beam and the divergent beam;
wherein a cylinder lens is used in the convergent recording beam to minimize aberrations; wherein a position, tilt and focus of the cylinder lens are adjusted to minimize aberrations; wherein an HMD image comprises a virtual image coming from infinity; and
wherein a minimum angle of a convergent beam with a holographic polymer surface comprises about 14° and a maximal angle of the convergent beam with the holographic polymer surface comprises about 31° with a central beam having 15°-25° angle.