METHOD AND SYSTEM FOR FIBER SCANNING PROJECTOR WITH ANGLED EYEPIECE
A wearable display system includes a fiber scanner including an optical fiber and a scanning mechanism configured to scan a tip of the optical fiber along an emission trajectory defining an optical axis. The wearable display system also includes an eyepiece positioned in front of the tip of the optical fiber and including a planar waveguide, an incoupling diffractive optical element (DOE) coupled to the planar waveguide, and an outcoupling DOE coupled to the planar waveguide. The wearable display system further includes a collimating optical element configured to receive light reflected by the incoupling DOE and collimate and reflect light toward the eyepiece.
1 . A wearable display system comprising:
a fiber scanner including:
an optical fiber; and
a scanning mechanism configured to scan a tip of the optical fiber along an emission trajectory defining an optical axis;
an eyepiece positioned in front of the tip of the optical fiber, the eyepiece including:
a planar waveguide having a first surface facing the tip of the optical fiber and a second surface opposite the first surface, the planar waveguide oriented such that a normal of the planar waveguide is tilted at a first angle with respect to the optical axis;
an incoupling diffractive optical element (DOE) coupled to the second surface of the planar waveguide in a first lateral region that is intercepted by the optical axis, the incoupling DOE comprising a metallized back surface and configured to reflect a first portion of an input light beam emitted from the optical fiber; and
an outcoupling DOE coupled to a second lateral region of the planar waveguide and configured to diffract a portion of light propagating in the planar waveguide out of the planar waveguide toward an eye of a viewer; and
a collimating optical element configured to:
receive the first portion of the input light beam reflected by the incoupling DOE; and
collimate and reflect the first portion of the input light beam toward the eyepiece;
wherein the incoupling DOE is further configured to diffract a first fraction of the first portion of the input light beam.
2 . The wearable display system of claim 1 wherein the first portion of the input light beam is reflected by the incoupling DOE as a zeroth order reflection.
3 . The wearable display system of claim 2 wherein the first fraction of the first portion of the input light beam is diffracted by the incoupling DOE as a negative first order diffraction.
4 . The wearable display system of claim 1 wherein the incoupling DOE diffracts the first fraction of the first portion of the input light beam to form and direct a first pass first diffracted light beam into the planar waveguide that fails to propagate within the planar waveguide via total internal reflection.
5 . The wearable display system of claim 4 wherein the first pass first diffracted light beam comprises a positive first order diffraction.
6 . The wearable display system of claim 1 wherein the incoupling DOE diffracts the first fraction of the first portion of the input light beam to form and direct a first pass second diffracted light beam into the planar waveguide that propagates within the planar waveguide via total internal reflection.
7 . The wearable display system of claim 6 wherein the first pass second diffracted light beam comprises a negative first order diffraction.
8 . The wearable display system of claim 1 wherein the incoupling DOE diffracts the first fraction of the first portion of the input light beam to form and direct a second pass second diffracted light beam into the planar waveguide that fails to propagate within the planar waveguide via total internal reflection.
9 . The wearable display system of claim 8 wherein the second pass second diffracted light beam comprises a positive first order diffraction.
10 . The wearable display system of claim 1 wherein the collimating optical element comprises a concave mirror.
11 . The wearable display system of claim 1 wherein the tip of the optical fiber is positioned on a first side of the eyepiece and the collimating optical element is positioned on the first side of the eyepiece.
12 . The wearable display system of claim 1 wherein the emission trajectory of the tip of the optical fiber is forms a two-dimensional convex surface.
13 . The wearable display system of claim 1 wherein the emission trajectory of the tip of the optical fiber forms a one-dimensional arc.
14 . The wearable display system of claim 1 wherein the tip of the optical fiber comprises an angled facet.
15 . The wearable display system of claim 1 wherein the input light beam is imagewise modulated.
16 . The wearable display system of claim 1 wherein the optical fiber comprises a non-polarization-maintaining optical fiber and the input light beam is unpolarized.
17 . The wearable display system of claim 1 wherein the first angle comprises an oblique angle.