Wearable pupil-forming display apparatus
A wearable display apparatus is described herein. The wearable display apparatus includes an image generator that forms a 2D image, a partially transmissive mirror having a curved focal surface and a partially transmissive curved reflective surface, a beam splitter, and an optical image relay positioned between the image generator and the beam splitter. The optical image relay includes a right-angle prism, a first plano-aspheric lens, a doublet positioned between the first plano-aspheric lens and the image generator, a meniscus singlet lens positioned between the doublet and the image generator, and a concave-plano field lens.
1. A wearable display apparatus comprising:
a catadioptric pupil-forming optical system including:
an image generator that forms a 2D image;
a partially transmissive mirror having a curved focal surface and a partially transmissive curved reflective surface;
a beam splitter disposed to reflect light toward the partially transmissive mirror, wherein the curved focal surface is defined in a space between the partially transmissive curved reflective surface and the beam splitter; and
an optical image relay positioned between the image generator and the beam splitter, and configured to conjugate the formed 2D image from the image generator to the curved focal surface of the partially transmissive mirror, the optical image relay includes:
a right-angle prism having a prism input surface, a prism output surface, and a folding surface extending from the prism input surface to the prism output surface, the folding surface is configured to fold an optical path for light generated by the image generator towards the beam splitter;
a first plano-aspheric lens cemented to the prism input surface and configured to guide light from the image generator toward the folding surface and to form an aperture stop for the optical image relay at the folding surface;
a doublet positioned between the first plano-aspheric lens and the image generator;
a meniscus singlet lens positioned between the doublet and the image generator;
a concave-plano field lens positioned between the meniscus singlet and the image generator; and
a second plano-aspheric lens cemented to the prism output surface and configured to direct the light to the curved focal surface;
wherein the optical image relay, the partially transmissive mirror, and the beam splitter are configured to form an exit pupil for viewing the 2D image superimposed on a portion of a visible object scene.
2. The wearable display apparatus of claim 1 , wherein the image generator includes a flat-panel display.
3. The wearable display apparatus of claim 1 , wherein the image generator includes an organic light-emitting device (OLED).
4. The wearable display apparatus of claim 1 , wherein the image generator includes a micro-LED array and lenslets.
5. The wearable display apparatus of claim 1 , wherein the partially transmissive mirror has a conic surface shape.
6. The wearable display apparatus of claim 1 , wherein the partially transmissive mirror is between about 30% to 70% transmissive.
7. The wearable display apparatus of claim 1 , wherein the folding surface of the right-angle prism is coated to enhance reflection.
8. The wearable display apparatus of claim 1 , wherein the beam splitter is a wire grid polarization beam splitter.
9. The wearable display apparatus of claim 1 , further comprising a cylindrically curved quarter-wave plate (QWP) between the partially transmissive mirror and the beam splitter.
10. The wearable display apparatus of claim 1 , wherein the catadioptric pupil-forming optical system forms a 10 mm exit pupil at a viewer's eye-box.
11. An augmented reality head-mounted-display (AR-HMD) system, comprising:
a headset including an optical module housing configured to be disposed above an eyes of a viewer;
a left-eye catadioptric pupil-forming optical system coupled to the optical module housing and configured to display a first image to a left-eye of the viewer; and
a right-eye catadioptric pupil-forming optical system coupled to the optical module housing and configured to display a second image to a right-eye of the viewer;
wherein each left-eye and right-eye catadioptric pupil-forming optical system includes:
an image generator that forms a 2D image;
a partially transmissive mirror having a curved focal surface and a partially transmissive curved reflective surface;
a beam splitter disposed to reflect light toward the partially transmissive mirror, wherein the curved focal surface is defined in a space between the partially transmissive curved reflective surface and the beam splitter; and
an optical image relay positioned between the image generator and the beam splitter, and configured to conjugate the formed 2D image from the image generator to the curved focal surface of the partially transmissive mirror, the optical image relay includes:
a right-angle prism having a prism input surface, a prism output surface, and a folding surface extending from the prism input surface to the prism output surface, the folding surface is configured to fold an optical path for light generated by the image generator towards the beam splitter;
a first plano-aspheric lens cemented to the prism input surface and configured to guide light from the image generator toward the folding surface and to form an aperture stop for the optical image relay at the folding surface;
a doublet positioned between the first plano-aspheric lens and the image generator;
a meniscus singlet lens positioned between the doublet and the image generator;
a concave-plano field lens positioned between the meniscus singlet and the image generator; and
a second plano-aspheric lens cemented to the prism output surface and configured to direct the light to the curved focal surface;
wherein the optical image relay, the partially transmissive mirror, and the beam splitter are configured to form an exit pupil for viewing the 2D image superimposed on a portion of a visible object scene.
12. The AR-HMD system of claim 11 , wherein the image generator includes a flat-panel display.
13. The AR-HMD system of claim 11 , wherein the image generator includes an organic light-emitting device (OLED).
14. The AR-HMD system of claim 11 , wherein the image generator includes a micro-LED array and lenslets.
15. The AR-HMD system of claim 11 , wherein the partially transmissive mirror has a conic surface shape.
16. The AR-HMD system of claim 11 , wherein the partially transmissive mirror is between about 30% to 70% transmissive.
17. The AR-HMD system of claim 11 , wherein the folding surface of the right-angle prism is coated to enhance reflection.
18. The AR-HMD system of claim 11 , wherein the beam splitter is a wire grid polarization beam splitter.
19. The AR-HMD system of claim 11 , wherein each left-eye and right-eye catadioptric pupil-forming optical system includes a cylindrically curved quarter-wave plate (QWP) between the partially transmissive mirror and the beam splitter.
20. The AR-HMD system of claim 11 , wherein each left-eye and right-eye catadioptric pupil-forming optical system forms a 10 mm exit pupil at a viewer's eye-box.