Scanning mirror and integrated projector

Abstract

To provide a favorable projector integrated with a scanning mirror.SOLUTION: A waveguide display system may include an eyepiece waveguide that can have a first surface and a second surface, the waveguide including an incoupling diffractive optical element (DOE) and an outcoupling DOE. The waveguide display system may include a light source and a scanning mirror, and may include reflective and collimating optical elements. The incoupling DOE can be configured to selectively propagate incident light beams to the outcoupling DOE in the waveguide through total internal reflection (TIR).SELECTED DRAWING: Figure 14

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application is a continuation of U.S. Provisional Patent Application No. 62 / 738,900, filed on September 28, 2018 and entitled “METHOD AND SYSTEM FOR PROJECTOR INTEGRATED WITH A SCANNING MIRROR” (Attorney Docket No. 101782-006501US-1090265), U.S. Provisional Patent Application No. 62 / 896,138, filed on September 5, 2019 and entitled “PROJECTOR INTEGRATED WITH A SCANNING MIRROR” (Attorney Docket No. 101782-006502US-1147050), and U.S. Provisional Patent Application No. 62 / 896,138, filed on September 28, 2018 and entitled “METHOD AND SYSTEM FOR FIBER SCANNING PROJECTOR WITH ANGLED No. 62 / 738,907 (Attorney Docket No. 101782-006400US-1090266), entitled "METHOD AND SYSTEM FOR FIBER SCANNING PROJECTOR WITH ANGLED EYEPIECE," all three applications being commonly owned and incorporated herein by reference in their entireties. This application was filed on the same date as International Patent Application No. PCT / US2019 / 053538 (Attorney Docket No. 101782-006410WO-1152141), entitled "METHOD AND SYSTEM FOR FIBER SCANNING PROJECTOR WITH ANGLED EYEPIECE," which claims priority to U.S. Provisional Patent Application No. 62 / 738,907 (Attorney Docket No. 101782-006410WO-1152141), entitled "METHOD AND SYSTEM FOR FIBER SCANNING PROJECTOR WITH ANGLED EYEPIECE," filed on September 28, 2018. [Background technology]

[0002] Modern computing and display technologies have facilitated the development of systems for so-called "virtual reality" or "augmented reality" experiences, in which digitally reproduced images, or portions thereof, are presented to a viewer in a manner that appears or may be perceived as real. Virtual reality, or "VR", scenarios typically involve the presentation of digital or virtual image information without transparency to other actual real-world visual input, while augmented reality, or "AR", scenarios typically involve the presentation of digital or virtual image information as an augmentation to the visualization of the real world around the viewer.

[0003] Despite the advances made in these display technologies, there remains a need in the art for improved methods and systems relating to augmented reality systems, and particularly to display systems. Summary of the Invention [Means for solving the problem]

[0004] According to an embodiment of the present invention, a waveguide display system is provided. The waveguide display system includes a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE. The waveguide display system also includes a first reflective optical element configured to receive a first light beam transmitted toward the in-coupling DOE of the waveguide and the first light beam passing through the in-coupling DOE of the waveguide. The first reflective optical element is configured to reflect a second light beam toward the in-coupling DOE of the waveguide. The waveguide display system is configured to prevent the first light beam from propagating to the out-coupling DOE in the waveguide through total internal reflection (TIR) ​​and propagate the second light beam to the out-coupling DOE in the waveguide through TIR.

[0005] According to another embodiment of the present invention, a waveguide display system is provided. The waveguide display system includes a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE. The in-coupling DOE is a polarization-sensitive DOE configured to pass a light beam of a first polarization and diffract a light beam of a second polarization. The waveguide display system also includes a light source for transmitting a first light beam of a first polarization toward and through the in-coupling DOE toward the first surface of the waveguide, a first reflective optical element disposed adjacent to the second surface of the waveguide, and a waveplate disposed adjacent to the second surface of the waveguide between the waveguide and the first reflective optical element. The first reflective optical element is configured to receive the first light beam after passing through the in-coupling DOE and the waveplate. The first reflective optical element is configured to reflect the received first light beam through the waveplate toward the waveguide. The waveguide display system is configured to convert the first light beam from the first polarization to a second polarization after the two have passed through the wave plate, and to cause the internal coupling DOE to diffract the first light beam received from the first reflective optical element and the wave plate and propagate within the waveguide to the external coupling DOE through total internal reflection (TIR).

[0006] According to an embodiment of the present invention, a waveguide display system is provided. The waveguide display system includes a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE. The waveguide display system also includes a collimated light source for transmitting an input collimated light beam toward the first surface of the waveguide at a first angle of incidence, and a scanning mirror disposed adjacent to the second surface of the waveguide. The scanning mirror is configured to receive the input collimated light beam and provide a reflected collimated light beam toward the waveguide at a second angle of incidence. The in-coupling DOE is configured to prevent the collimated input light beam from propagating to the out-coupling DOE in the waveguide through total internal reflection (TIR) ​​and to propagate the reflected collimated light beam to the out-coupling DOE in the waveguide through total internal reflection (TIR).

[0007] According to another embodiment of the present invention, a waveguide display system is provided. The waveguide display system includes a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE, and a scanning light source disposed adjacent to the first surface of the waveguide. The scanning light source is configured to scan a diverging input light beam toward the in-coupling DOE at a first angle of incidence. The waveguide display system also includes a scanning mirror disposed adjacent to the second surface of the waveguide, the scanning mirror being a collimating optical element configured to receive the diverging input light beam from the scanning light source through the waveguide and provide a collimated reflected light beam toward the in-coupling DOE of the waveguide. The internal coupling DOE is configured to prevent a diverging input light beam from propagating to the external coupling DOE in the waveguide through total internal reflection (TIR) ​​and to propagate a collimated reflected light beam to the external coupling DOE in the waveguide through total internal reflection (TIR).

[0008] According to an embodiment of the present invention, a waveguide display system is provided. The waveguide display system includes a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element), an out-coupling DOE, and a scanning light source disposed adjacent to the first surface of the waveguide. The scanning light source is configured to scan a diverging input light beam into the in-coupling DOE of the waveguide at a first incidence angle. The waveguide display system also includes a scanning mirror disposed adjacent to the second surface of the waveguide, the scanning mirror configured to receive the diverging input light beam from the scanning light source through the waveguide and provide a diverging reflected light beam toward the in-coupling DOE at a second incidence angle, and a collimating optical element positioned adjacent to the first surface of the waveguide, the collimating optical element configured to receive the diverging reflected light beam emitted from the scanning mirror through the in-coupling DOE of the waveguide and produce a collimated light beam toward the waveguide. The internal coupling DOE is configured to prevent a diverging input light beam from the scanning light source from propagating through total internal reflection (TIR) ​​to the external coupling DOE in the waveguide, to prevent a diverging reflected light beam from the scanning mirror from propagating through TIR to the external coupling DOE in the waveguide, and to propagate a collimated light beam through TIR to the external coupling DOE in the waveguide.

[0009] According to an alternative embodiment of the present invention, a waveguide display system is provided that includes a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE, and a scanning light source disposed adjacent to the first surface of the waveguide, the scanning light source configured to project a diverging input light beam onto the waveguide at a first angle of incidence. The waveguide display system also includes a collimating optical element positioned adjacent to a first surface of the waveguide, the collimating optical element configured to receive the diverging input light beam emitted from the scanning light source and provide a collimated reflected light beam at a first angle of incidence toward the in-coupling DOE of the waveguide, and a scanning mirror positioned adjacent to a second surface of the waveguide, the scanning mirror configured to receive the collimated reflected light beam from the collimating optical element and provide a collimated scanned light beam at a second angle of incidence toward the in-coupling DOE of the waveguide. The in-coupling DOE is configured to prevent the collimated reflected light beam from the collimating optical element from propagating to the out-coupling DOE in the waveguide through total internal reflection (TIR) ​​and to propagate the collimated scanned light beam from the scanning mirror to the out-coupling DOE in the waveguide through total internal reflection (TIR).

[0010] In some of the above waveguide display systems, the scanning light source can be a fiber scanner including an optical fiber and a scanning mechanism configured to scan the optical fiber in a linear direction such that a tip of the optical fiber is configured to scan along a track, the track defining a first optical axis. Alternatively, the scanning light source can be a cantilevered scanner including a cantilevered optical element having a waveguide and a scanning mechanism configured to scan the cantilevered optical element in a linear direction such that a tip of the cantilevered optical element is configured to scan along a track, the track defining a first optical axis.

[0011] According to yet another embodiment of the present invention, a waveguide display system is provided. The waveguide display system includes a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE, and a point light source disposed adjacent to the second surface of the waveguide. The point light source is configured to provide a diverging input light beam to a portion of the waveguide outside the in-coupling DOE. The waveguide display system also includes a scanning mirror disposed adjacent to the second surface of the waveguide, the scanning mirror configured to receive the diverging input light beam from the point light source and provide a diverging reflected light beam toward the in-coupling DOE of the waveguide, and a collimating lens positioned adjacent to the second surface of the waveguide between the scanning mirror and the waveguide. The collimating lens is configured to receive the diverging reflected light beam emitted from the scanning mirror and produce a collimated reflected light beam toward the in-coupling DOE of the waveguide. The in-coupling DOE is configured to diffract the collimated reflected light beam and propagate it through total internal reflection (TIR) ​​to the out-coupling DOE within a waveguide.

[0012] According to yet another specific embodiment of the present invention, a waveguide display system is provided. The waveguide display system includes a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE, and a point light source disposed adjacent to the first surface of the waveguide. The point light source is configured to provide a diverging input light beam to a portion of the waveguide outside the in-coupling DOE. The waveguide display system also includes a scanning mirror disposed adjacent to the second surface of the waveguide, the scanning mirror configured to receive the diverging input light beam from the point light source through the waveguide and provide a diverging reflected light beam toward the in-coupling DOE of the waveguide. The waveguide display system further includes a collimating optical element positioned adjacent to the first surface of the waveguide, the collimating optical element configured to receive the diverging reflected light beam emitted from the scanning mirror through the in-coupling DOE of the waveguide and produce a collimated reflected light beam toward the in-coupling DOE of the waveguide. The in-coupling DOE is configured to prevent the diverging reflected light beam from the scanning mirror from propagating to the out-coupling DOE in the waveguide through total internal reflection (TIR) ​​and to propagate the collimated reflected light beam to the out-coupling DOE in the waveguide through total internal reflection (TIR).

[0013] According to yet another alternative embodiment of the present invention, a waveguide display system is provided. The waveguide display system includes a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE, a collimating scanning optical element positioned adjacent to the first surface of the waveguide, and a scanning mirror disposed adjacent to the second surface of the waveguide. The waveguide display system also includes a point light source disposed adjacent to the second surface of the waveguide. The point light source is configured to provide a diverging input light beam to the scanning mirror. The scanning mirror is configured to receive the diverging input light beam from the point light source and provide a diverging reflected light beam toward the waveguide at a first angle of incidence. The collimating optical element is configured to receive the diverging reflected light beam emitted from the scanning mirror through the in-coupling DOE of the waveguide and produce a collimated reflected light beam toward the waveguide at a second angle of incidence. The internal coupling DOE is configured to prevent a diverging reflected light beam from the scanning mirror from propagating to the external coupling DOE in the waveguide through total internal reflection (TIR) ​​and to propagate a collimated reflected light beam to the external coupling DOE in the waveguide through total internal reflection (TIR).

[0014] In some of the above-described waveguide display systems, the point source may include a fiber point source or a cantilevered point source.

[0015] According to still some alternative embodiments of the present invention, the two-dimensional scanning light source includes a cantilevered scanner configured to provide a scanned light beam, and a reflective optical element disposed adjacent to the cantilevered scanner and configured to receive the scanned light beam and provide a reflected scanned light beam. The two-dimensional scanning light source also includes a collimating optical element disposed adjacent to the reflective optical element and configured to receive the reflected scanned light beam from the reflective optical element and provide a collimated scanned light beam. The two-dimensional scanning light source also includes a scanning optical element disposed adjacent to the collimating optical element and configured to receive the collimated scanned light beam and provide a collimated two-dimensional scanned light beam.

[0016] According to some embodiments of the present invention, a waveguide display system includes a waveguide, a cantilevered scanner, a reflective optical element, a collimating optical element, and a scanning optical element. The waveguide has a first surface and a second surface and includes an in-coupling DOE (diffractive optical element) and an out-coupling DOE. The cantilevered scanner is disposed adjacent to the first surface of the waveguide and configured to provide a scanning light beam. The reflective optical element is disposed adjacent to the cantilevered scanner and configured to receive the scanning light beam and provide a reflected scanning light beam. The collimating optical element is disposed adjacent to the reflective optical element and configured to receive the reflected scanning light beam from the reflective optical element and provide a collimated scanning light beam. The scanning optical element is disposed adjacent to the collimating optical element and configured to receive the collimated scanning light beam and provide a collimated two-dimensional scanning light beam. The cantilevered scanner, the reflective optical element, the collimating optical element, and the scanning optical element are disposed on the same side of the waveguide adjacent to the first surface, The waveguide is configured to receive the collimated two-dimensional scanning light beam at the in-coupling DOE and propagate the collimated two-dimensional scanning light beam to the out-coupling DOE through total internal reflection (TIR).

[0017] The following description, together with the accompanying drawings, provides further explanation of the nature and advantages of the claimed invention. The present invention provides, for example, the following: (Item 1) 1. A waveguide display system comprising: a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE; a first light beam transmitted toward the waveguide in-coupling DOE; a first reflective optical element configured to receive the first light beam passing through the waveguide in-coupling DOE, the first reflective optical element configured to reflect a second light beam towards the waveguide in-coupling DOE; Equipped with The waveguide display system comprises: Preventing propagation of the first light beam to an out-coupled DOE within the waveguide via total internal reflection (TIR); propagating the second light beam through a TIR to an outcoupled DOE in the waveguide; A waveguide display system configured to: (Item 2) 2. The waveguide display system of item 1, wherein the angles of incidence of the first and second light beams and the grating period of the internal coupling DOE are configured to determine a diffraction angle such that the first light beam transmitting through the internal coupling DOE does not satisfy the TIR condition for the first light beam to propagate to the external coupling DOE, and the second light beam reaching the internal coupling DOE satisfies the TIR condition for propagating to the external coupling DOE. (Item 3) diffraction of the first light beam by the incoupling DOE results in a first negative first order diffracted light beam that lacks a total internal reflection (TIR) ​​condition of the waveguide; diffraction of the second light beam by the incoupling DOE results in a second negative first order diffracted light beam that satisfies the TIR condition of the waveguide. Item 2. The waveguide display system of item 1. (Item 4) the first light beam is a non-scanned collimated image beam; the first reflective optical element is a scanning mirror; Item 2. The waveguide display system of item 1. (Item 5) Item 2. The waveguide display system of item 1, wherein the first light beam is a diverging light beam provided by a scanning light source and the first reflective optical element is a collimating scanning mirror. (Item 6) Item 6. The waveguide display system of item 5, wherein the scanning light source comprises a fiber scanner. (Item 7) Item 6. The waveguide display system of item 5, wherein the scanning light source comprises a cantilever scanner. (Item 8) the first light beam is a collimated light beam provided by a collimating mirror; The first reflective optical element can be a non-collimated scanning mirror. Item 2. The waveguide display system of item 1. (Item 9) a scanning mirror and a light source, the first light beam being a scanned diverging light beam provided by the scanning mirror; the scanning mirror is configured to receive an input light beam from the light source and provide the scanned diverging light beam, the scanned diverging light beam being transmitted through the waveguide to the first reflective optical element; the first reflective optical element is a collimating mirror configured to receive the scanned diverging light beam and provide a reflected collimated light beam to the waveguide; Item 2. The waveguide display system of item 1. (Item 10) 10. The waveguide display system of claim 9, wherein the light source comprises a fiber scanner. (Item 11) 10. The waveguide display system of claim 9, wherein the light source comprises a cantilever scanner. (Item 12) Item 10. The waveguide display system of item 9, wherein the light source comprises a fiber point source. (Item 13) 10. The waveguide display system of claim 9, wherein the light source comprises a waveguide disposed on a cantilever. (Item 14) 10. The waveguide display system of claim 9, wherein the light source and the scanning mirror are disposed on the same side of the waveguide. (Item 15) 10. The waveguide display system of claim 9, wherein the light source and the scanning mirror are disposed on opposite sides of the waveguide. (Item 16) Item 16. The waveguide display system of item 15, wherein the internal coupling DOE is configured to prevent propagation of the input light beam to the external coupling DOE within the waveguide via total internal reflection (TIR). (Item 17) Item 16. The waveguide display system of item 15, wherein the waveguide display system is configured such that the input light beam is incident on the waveguide without traveling through the internally coupled DOE. (Item 18) 1. A waveguide display system comprising: a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE, the in-coupling DOE being a polarization-sensing DOE configured to pass a light beam of a first polarization and diffract a light beam of a second polarization; a light source for transmitting a first light beam of a first polarization through the incoupling DOE towards a first surface of the waveguide; a first reflective optical element disposed adjacent to a second surface of the waveguide; a waveplate adjacent to a second surface of the waveguide and disposed between the waveguide and the first reflective optical element; Equipped with the first reflective optical element is configured to receive the first light beam after passing through the in-coupling DOE and the wave plate; the first reflective optical element is configured to reflect the received first light beam through the wave plate toward the waveguide; The waveguide display system comprises: converting the first light beam from the first polarization to the second polarization after the two have passed through the wave plate; causing the in-coupling DOE to diffract the first light beam received from the first reflective optical element and the waveplate and propagate through total internal reflection (TIR) ​​in the waveguide to the out-coupling DOE; A waveguide display system configured to: (Item 19) Item 19. The waveguide display system of item 18, wherein the first light beam is a collimated light beam. (Item 20) Item 19. The waveguide display system of item 18, wherein the first reflective optical element is a scanning mirror. (Item 21) Item 19. The waveguide display system of item 18, wherein the wave plate is a quarter wave plate. (Item 22) 1. A waveguide display system comprising: a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE; a collimated light source for transmitting an input collimated light beam toward a first surface of the waveguide at a first angle of incidence; a scanning mirror disposed adjacent to a second surface of the waveguide, the scanning mirror configured to receive the input collimated light beam and provide a reflected collimated light beam toward the waveguide at a second angle of incidence; Equipped with The internal bond DOE is preventing the collimated input light beam from propagating through total internal reflection (TIR) ​​to an out-coupled DOE within the waveguide; propagating the reflected collimated light beam to an out-coupled DOE within the waveguide via total internal reflection (TIR); A waveguide display system configured to: (Item 23) 23. The waveguide display system of claim 22, wherein an internally coupled DOE is disposed adjacent to a first surface of the waveguide. (Item 24) 23. The waveguide display system of item 22, wherein the angles of incidence of the input collimated light beam and the reflected collimated light beam and the grating period of the internal coupling DOE are configured to determine a diffraction angle such that the input collimated light beam transmitting through the internal coupling DOE does not satisfy the TIR condition for propagating to the external coupling DOE and the reflected collimated light beam reaching the internal coupling DOE satisfies the TIR condition for propagating to the external coupling DOE. (Item 25) 1. A waveguide display system comprising: a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE; a scanning light source disposed adjacent a first surface of the waveguide, the scanning light source configured to scan a diverging input light beam towards the incoupling DOE at a first angle of incidence; a scanning mirror disposed adjacent to a second surface of the waveguide, the scanning mirror being a collimating optical element configured to receive the diverging input light beam from the scanning light source through the waveguide and provide a collimated reflected light beam towards the waveguide-intercoupled DOE; and Equipped with The internal bond DOE is preventing the diverging input light beam from propagating through total internal reflection (TIR) ​​to an out-coupled DOE within the waveguide; propagating the collimated reflected light beam to an out-coupled DOE within the waveguide via total internal reflection (TIR); A waveguide display system configured to: (Item 26) Item 26. The waveguide display system of item 25, wherein the incoupling DOE is a periodic grating having a pitch configured to selectively incoupling light beams of different angles of incidence. (Item 27) 26. The waveguide display system of item 25, wherein the internal coupling DOE is configured to diffract the diverging input light beam to produce a first negative first order diffracted light beam that lacks a total internal reflection (TIR) ​​condition of the waveguide. (Item 28) 26. The waveguide display system of item 25, wherein the internal coupling DOE is configured to diffract the collimated reflected light beam to produce a second negative first-order diffracted light beam that satisfies the total internal reflection (TIR) ​​condition of the waveguide. (Item 29) The scanning light source comprises a fiber scanner, the fiber scanner comprising: An optical fiber; a scanning mechanism configured to scan the optical fiber in a linear direction such that a tip of the optical fiber is configured to scan along a trajectory, the trajectory defining a first optical axis; 26. The waveguide display system of item 25, comprising: (Item 30) The scanning light source comprises a cantilever scanner, the cantilever scanner comprising: a cantilevered optical member including a waveguide; a scanning mechanism configured to scan the cantilevered optical member in a linear direction such that a tip of the cantilevered optical member is configured to scan along a trajectory, the trajectory defining a first optical axis; 26. The waveguide display system of item 25, comprising: (Item 31) 26. The waveguide display system of claim 25, wherein the first angle of incidence is formed between an optical axis of the diverging input light beam and a normal to a first surface of the waveguide. (Item 32) 26. The waveguide display system of claim 25, wherein the scanning mirror is configured to provide a collimated reflected light beam along a second optical axis toward the waveguide at a second angle of incidence, the second angle of incidence being defined by the second optical axis and a normal to a first surface of the waveguide. (Item 33) Item 26. The waveguide display system of item 25, wherein the scanning mirror is a one-axis scanning mirror that scans in a direction perpendicular to a scanning direction of the scanning light source. (Item 34) 1. A waveguide display system comprising: a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE; a scanning light source disposed adjacent to a first surface of the waveguide, the scanning light source configured to scan a diverging input light beam into the waveguide-intercoupled DOE at a first angle of incidence; a scanning mirror disposed adjacent a second surface of the waveguide, the scanning mirror configured to receive the diverging input light beam from the scanning light source through the waveguide and to provide a diverging reflected light beam towards the incoupling DOE at a second angle of incidence; a collimating optical element positioned adjacent to a first surface of the waveguide, the collimating optical element configured to receive the diverging reflected light beam emitted from the scanning mirror through an internal coupling DOE of the waveguide and produce a collimated light beam towards the waveguide; Equipped with The internal bond DOE is preventing the diverging input light beam from the scanning light source from propagating through total internal reflection (TIR) ​​to an out-coupled DOE within the waveguide; preventing the diverging reflected light beam from the scanning mirror from propagating through total internal reflection (TIR) ​​to an outcoupled DOE in the waveguide; propagating the collimated light beam to an out-coupled DOE in the waveguide via total internal reflection (TIR); A waveguide display system configured to: (Item 35) Item 35. The waveguide display system of item 34, wherein the internally coupled DOE is disposed adjacent to a first surface of the waveguide. (Item 36) Item 35. The waveguide display system of item 34, wherein the incoupling DOE is a periodic grating having a pitch configured to selectively incoupling light beams of different angles of incidence. (Item 37) The scanning light source comprises a fiber scanner, the fiber scanner comprising: An optical fiber; a scanning mechanism configured to scan the optical fiber in a linear direction such that a tip of the optical fiber is configured to scan along a trajectory, the trajectory defining a first optical axis; Item 35. The waveguide display system of item 34, comprising: (Item 38) The scanning light source comprises a cantilever scanner, the cantilever scanner comprising: a cantilevered optical member including a waveguide; a scanning mechanism configured to scan the cantilevered optical member in a linear direction such that a tip of the cantilevered optical member is configured to scan along a trajectory, the trajectory defining a first optical axis; Item 35. The waveguide display system of item 34, comprising: (Item 39) Item 35. The waveguide display system of item 34, wherein the scanning mirror is a one-axis scanning mirror that scans in a direction perpendicular to a scanning direction of the scanning light source. (Item 40) 1. A waveguide display system comprising: a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE; a scanning light source disposed adjacent a first surface of the waveguide, the scanning light source configured to project a diverging input light beam onto the waveguide at a first angle of incidence; a collimating optical element positioned adjacent to a first surface of the waveguide, the collimating optical element configured to receive the diverging input light beam emitted from the scanning light source and to produce a collimated reflected light beam at a first angle of incidence towards an in-coupling DOE of the waveguide; a scanning mirror disposed adjacent to a second surface of the waveguide, the scanning mirror configured to receive the collimated reflected light beam from the collimating optical element and provide a collimated scanned light beam at a second angle of incidence towards an in-coupling DOE of the waveguide; Equipped with The internal bond DOE is preventing the collimated reflected light beam from the collimating optical element from propagating through total internal reflection (TIR) ​​to an out-coupled DOE in the waveguide; propagating the collimated scanned light beam from the scanning mirror to an out-coupled DOE in the waveguide via total internal reflection (TIR); A waveguide display system configured to: (Item 41) Item 41. The waveguide display system of item 40, wherein the internally coupled DOE is disposed adjacent to a first surface of the waveguide. (Item 42) Item 41. The waveguide display system of item 40, wherein the incoupling DOE is a periodic grating having a pitch configured to selectively incoupling light beams of different angles of incidence. (Item 43) The scanning light source comprises a fiber scanner, the fiber scanner comprising: an optical fiber having a facet that is angled such that a light beam emitted from a tip of the optical fiber is refracted at an angle relative to an axis of the optical fiber; a scanning mechanism configured to scan the optical fiber in a linear direction such that a tip of the optical fiber is configured to scan along a trajectory, the trajectory defining a first optical axis; Item 41. The waveguide display system of item 40, comprising: (Item 44) The scanning light source comprises a cantilever scanner, the cantilever scanner comprising: a cantilevered optical member including a waveguide; a scanning mechanism configured to scan the cantilevered optical member in a linear direction such that a tip of the cantilevered optical member is configured to scan along a trajectory, the trajectory defining a first optical axis; Item 41. The waveguide display system of item 40, comprising: (Item 45) Item 41. The waveguide display system of item 40, wherein the collimating optical element comprises a cross section of a concave collimating mirror. (Item 46) Item 46. The waveguide display system of item 45, wherein the normal of the collimating optical element is positioned at an angle to the scanning light source such that the collimated reflected light beam from the collimating optical element is directed away from the scanning light source. (Item 47) Item 41. The waveguide display system of item 40, wherein the scanning mirror is a one-axis scanning mirror that scans in a direction perpendicular to a scanning direction of the scanning light source. (Item 48) 1. A waveguide display system comprising: a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE; a point light source disposed adjacent a second surface of the waveguide, the point light source configured to provide a diverging input light beam to a portion of the waveguide outside the in-coupling DOE; a scanning mirror disposed adjacent to a second surface of the waveguide, the scanning mirror configured to receive the diverging input light beam from the point light source and to provide a diverging reflected light beam towards the waveguide-intercoupled DOE; and a collimating lens positioned adjacent a second surface of the waveguide and between the scanning mirror and the waveguide, the collimating lens configured to receive the diverging reflected light beam emitted from the scanning mirror and produce a collimated reflected light beam toward an in-coupling DOE of the waveguide; Equipped with The in-coupling DOE is configured to diffract the collimated reflected light beam and propagate it through total internal reflection (TIR) ​​to an out-coupling DOE within the waveguide, a waveguide display system. (Item 49) Item 49. The waveguide display system of item 48, wherein the point light source comprises a fiber point light source or a cantilevered point light source. (Item 50) 1. A waveguide display system comprising: a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE; a point light source disposed adjacent a first surface of the waveguide, the point light source configured to provide a diverging input light beam to a portion of the waveguide outside the in-coupling DOE; a scanning mirror disposed adjacent to a second surface of the waveguide, the scanning mirror configured to receive the diverging input light beam from the point light source through the waveguide and to provide a diverging reflected light beam towards the waveguide-intercoupled DOE; and a collimating scanning optical element positioned adjacent to a first surface of the waveguide, the collimating optical element configured to receive the diverging reflected light beam emitted from the scanning mirror through the waveguide in-coupling DOE and produce a collimated reflected light beam toward the waveguide in-coupling DOE; Equipped with The internal bond DOE is preventing the diverging reflected light beam from the scanning mirror from propagating through total internal reflection (TIR) ​​to an outcoupled DOE in the waveguide; propagating the collimated reflected light beam to an out-coupled DOE within the waveguide via total internal reflection (TIR); A waveguide display system configured to: (Item 51) Item 51. The waveguide display system of item 50, wherein the internally coupled DOE is disposed adjacent to a first surface of the waveguide. (Item 52) Item 51. The waveguide display system of item 50, wherein the incoupling DOE is a periodic grating having a pitch configured to selectively incoupling light beams of different angles of incidence. (Item 53) The internal bond DOE is passing the diverging reflected light beam from the scanning mirror; in-coupling the collimated reflected light beam from the collimating optical element and propagating it through total internal reflection (TIR) ​​to an out-coupling DOE in the waveguide; Item 53. The waveguide display system of item 52, configured to perform the following: (Item 54) Item 51. The waveguide display system of item 50, wherein the point light source comprises a fiber point light source, the fiber point light source including an optical fiber having a tip with an angled facet, the optical fiber configured to emit a light beam in a direction at an angle relative to an axis of the optical fiber. (Item 55) Item 51. The waveguide display system of item 50, wherein the point light source comprises a cantilever scanner with a waveguide. (Item 56) 1. A waveguide display system comprising: a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE; a collimating scanning optical element positioned adjacent to a first surface of the waveguide; a scanning mirror disposed adjacent to a second surface of the waveguide; a point light source disposed adjacent to a second surface of the waveguide, the point light source configured to provide a diverging input light beam to the scanning mirror; Equipped with the scanning mirror is configured to receive the diverging input light beam from the point source and to provide a diverging reflected light beam towards the waveguide at a first angle of incidence; the collimating scanning optical element is configured to receive the diverging reflected light beam emitted from the scanning mirror through an internal coupling DOE of the waveguide and produce a collimated reflected light beam toward the waveguide; The internal bond DOE is preventing the diverging reflected light beam from the scanning mirror from propagating through total internal reflection (TIR) ​​to an outcoupled DOE in the waveguide; propagating the collimated reflected light beam to an out-coupled DOE within the waveguide via total internal reflection (TIR); A waveguide display system configured to: (Item 57) Item 57. The waveguide display system of item 56, wherein the internally coupled DOE is disposed adjacent to a first surface of the waveguide. (Item 58) Item 57. The waveguide display system of item 56, wherein the incoupling DOE is a periodic grating having a pitch configured to selectively incoupling light beams of different angles of incidence. (Item 59) The internal bond DOE is passing the diverging reflected light beam from the scanning mirror; in-coupling the collimated reflected light beam from the collimated scanning optical element and propagating it through TIR to an out-coupling DOE in the waveguide; Item 57. The waveguide display system of item 56, configured to perform the following: (Item 60) Item 57. The waveguide display system of item 56, wherein the point light source comprises a fiber point light source, the fiber point light source including an optical fiber having a tip with an angled facet, the optical fiber configured to emit a light beam in a direction at an angle relative to an axis of the optical fiber. (Item 61) Item 57. The waveguide display system of item 56, wherein the point light source comprises a cantilever scanner with a waveguide. (Item 62) the scanning mirror is configured to provide the diverging reflected light beam towards the waveguide at a first angle of incidence; the collimated scanning optical element is configured to produce a collimated reflected light beam toward the waveguide at a second angle of incidence. Item 57. A waveguide display system according to item 56. (Item 63) A two-dimensional scanning light source, a cantilever scanner configured to provide a scanned light beam; a reflective optical element disposed adjacent to the cantilever scanner and configured to receive the scanning light beam and provide a reflected scanning light beam; a collimating optical element disposed adjacent to the reflective optical element and configured to receive the reflected scanning light beam from the reflective optical element and provide a collimated scanning light beam; a scanning optical element disposed adjacent to the collimating optical element and configured to receive the collimated scanning light beam and provide a collimated two-dimensional scanning light beam; A two-dimensional scanning light source comprising: (Item 64) The cantilever scanner includes: A base portion; a cantilevered optical member protruding from the base portion, the cantilevered optical member including a waveguide for coupling to a light source; a transducer assembly comprising one or more piezoelectric actuators coupled to the cantilevered optical member and configured to induce movement of the cantilevered optical member in a first scan plane to provide the scanned light beam; Item 64. The two-dimensional scanning light source according to item 63, comprising: (Item 65) Item 65. The two-dimensional scanning light source of item 64, wherein the base portion of the cantilever scanner comprises a layer of single crystal silicon, and the cantilever optical element is integrally formed with the layer of single crystal silicon and comprises a cantilever beam protruding therefrom. (Item 66) Item 65. The two-dimensional scanning light source of item 64, wherein each of the one or more piezoelectric actuators is oriented in a direction substantially parallel to a longitudinal axis of the cantilevered optical element. (Item 67) Item 65. The two-dimensional scanning light source of item 64, wherein the scanning optical element is a one-axis scanning mirror that scans in a second plane orthogonal to the first scanning plane of the cantilever scanner. (Item 68) Item 64. The two-dimensional scanning light source of item 63, wherein the collimating optical element comprises a mirror with positive refractive power. (Item 69) Item 69. The two-dimensional scanning light source of item 68, wherein the collimating optical element is a concave mirror. (Item 70) Item 64. The two-dimensional scanning light source of item 63, wherein the cantilever scanner, the reflective optical element, the collimating optical element, and the scanning optical element are integrated within a silicon MEMS device. (Item 71) 1. A waveguide display system comprising: a waveguide having a first surface and a second surface, the waveguide including an in-coupling DOE (diffractive optical element) and an out-coupling DOE; a cantilever scanner disposed adjacent to a first surface of the waveguide, the cantilever scanner configured to provide a scanned light beam; a reflective optical element disposed adjacent to the cantilever scanner and configured to receive the scanning light beam and provide a reflected scanning light beam; a collimating optical element disposed adjacent to the reflective optical element and configured to receive the reflected scanning light beam from the reflective optical element and provide a collimated scanning light beam; a scanning optical element disposed adjacent to the collimating optical element and configured to receive the collimated scanning light beam and provide a collimated two-dimensional scanning light beam; Equipped with the cantilevered scanner, the reflective optical element, the collimating optical element, and the scanning optical element are disposed on the same side of the waveguide adjacent the first surface; the waveguide is configured to receive the collimated two-dimensional scanning light beam at the in-coupling DOE and propagate the collimated two-dimensional scanning light beam to the out-coupling DOE through total internal reflection (TIR). Waveguide display system. (Item 72) The cantilever scanner includes: A base portion; a cantilevered optical member protruding from the base portion, the cantilevered optical member including a waveguide for coupling to a light source; a transducer assembly comprising one or more piezoelectric actuators coupled to the cantilevered optical member and configured to induce movement of the cantilevered optical member in a first scan plane to provide the scanned light beam; Item 72. The waveguide display system of item 71, comprising: (Item 73) Item 73. The waveguide display system of item 72, wherein the base portion of the cantilever scanner comprises a layer of single crystal silicon, and the cantilever optical element comprises a cantilever beam integrally formed with and protruding from the layer of single crystal silicon. (Item 74) Item 73. The waveguide display system of item 72, wherein each of the one or more piezoelectric actuators is oriented in a direction generally parallel to a longitudinal axis of the cantilevered optical member. (Item 75) Item 72. The waveguide display system of item 71, wherein the collimating optical element comprises a mirror with positive optical power. (Item 76) Item 76. The waveguide display system of item 75, wherein the collimating optical element is a concave mirror. (Item 77) Item 72. The waveguide display system of item 71, wherein the scanning optical element is a one-axis scanning mirror that scans in a direction perpendicular to the scanning direction of the cantilever scanner. (Item 78) Item 72. The waveguide display system of item 71, wherein the cantilevered scanner, the reflective optical element, the collimating optical element, and the scanning optical element are positioned adjacent to and on the same side of a first surface of the waveguide. (Item 79) Item 72. The waveguide display system of item 71, wherein the cantilevered scanner, the reflective optical element, the collimating optical element, and the scanning optical element are integrated within a semiconductor MEMS device. (Item 80) Item 72. The waveguide display system of item 71, wherein the internally coupled DOE is disposed adjacent to a first surface of the waveguide. [Brief description of the drawings]

[0018] [Figure 1A] FIG. 1A is a simplified perspective view illustrating a fiber scanner, according to an embodiment of the present invention.

[0019] [Figure 1B] FIG. 1B is a simplified cutaway perspective view illustrating a fiber scanner, according to an embodiment of the present invention.

[0020] [Figure 2A]FIG. 2A diagrammatically illustrates light paths within a viewing optics assembly (VOA) that may be used to present a digital or virtual image to a viewer, according to an embodiment of the present invention.

[0021] [Figure 2B] FIG. 2B is a partial cross-sectional view illustrating the structure of an eyepiece according to an embodiment of the present invention.

[0022] [Diagram 3] FIG. 3 diagrammatically illustrates a fiber scanning projector coupled to an eyepiece according to some embodiments of the present invention.

[0023] [Figure 4] 4A and 4B are simplified schematic diagrams illustrating diffractive coupling of light for an angled internal coupling diffractive optical element as illustrated in FIG. 3 upon a first pass and a second pass, respectively, in accordance with an embodiment of the present invention.

[0024] [Diagram 5] FIG. 5 diagrammatically illustrates a fiber scanning projector coupled to an eyepiece according to some other embodiments of the present invention.

[0025] [Figure 6] 6A and 6B are simplified schematic diagrams illustrating the diffractive coupling of light for an angled internal coupling diffractive optical element as illustrated in FIG. 5 upon a first pass and a second pass, respectively, in accordance with an embodiment of the present invention.

[0026] [Figure 7] FIG. 7 diagrammatically illustrates a fiber scanning projector coupled to an eyepiece according to some further embodiments of the present invention.

[0027] [Figure 8]FIG. 8 diagrammatically illustrates a fiber scanning projector coupled to an eyepiece according to some other embodiments of the present invention.

[0028] [Figure 9] FIG. 9 diagrammatically illustrates a configuration including two fiber scanning projectors coupled to an eyepiece, according to some embodiments of the present invention.

[0029] [Figure 10] FIG. 10 diagrammatically illustrates a top view of a wearable display, according to some embodiments of the present invention.

[0030] [Figure 11] FIG. 11 diagrammatically illustrates a fiber scanning projector coupled to an eyepiece according to some further embodiments of the present invention.

[0031] [Figure 12A] FIG. 12A is a simplified schematic diagram illustrating a waveguide display system including a projector integrated with a scanning mirror according to some embodiments of the present invention.

[0032] [Figure 12B] FIG. 12B is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror according to some embodiments of the present invention.

[0033] [Figure 13] FIG. 13 is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror according to some embodiments of the present invention.

[0034] [Figure 14] FIG. 14 is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror according to some embodiments of the present invention.

[0035] [Figure 15A] FIG. 15A diagrammatically illustrates a perspective view of a fiber scanning projector, according to some embodiments.

[0036] [Figure 15B] FIG. 15B diagrammatically illustrates a side view of the fiber scanning projector illustrated in FIG. 15A.

[0037] [Figure 15C] FIG. 15C is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror according to some embodiments of the present invention.

[0038] [Figure 16] FIG. 16 is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror according to some embodiments of the present invention.

[0039] [Figure 17A] FIG. 17A is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror, according to some embodiments of the present invention.

[0040] [Figure 17B] FIG. 17B is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror according to some embodiments of the present invention.

[0041] [Figure 18A] 18A-18C are simplified perspective views illustrating various examples of cantilevered MEMS scanners, according to some embodiments of the present invention. [Figure 18B]18A-18C are simplified perspective views illustrating various examples of cantilevered MEMS scanners, according to some embodiments of the present invention. [Figure 18C] 18A-18C are simplified perspective views illustrating various examples of cantilevered MEMS scanners, according to some embodiments of the present invention.

[0042] [Figure 18D] FIG. 18D is an electrical schematic illustrating a four-phase signal splitter network for driving a piezoelectric actuator, according to some embodiments of the present invention.

[0043] [Figure 19] FIG. 19 is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror according to some embodiments of the present invention.

[0044] [Figure 20] FIG. 20 is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror according to some embodiments of the present invention.

[0045] [Figure 21A] FIG. 21A is a perspective view illustrating a cantilever scanning projector according to some embodiments of the present invention.

[0046] [Figure 21B] FIG. 21B diagrammatically illustrates a side view of the cantilever scanning projector illustrated in FIG. 21A.

[0047] [Figure 21C] FIG. 21C is a simplified schematic diagram illustrating another waveguide display system including a cantilevered projector integrated with a scanning mirror, according to some embodiments of the present invention.

[0048] [Figure 22A] FIG. 22A is a perspective view illustrating a two-dimensional scanning light source, according to some embodiments of the present invention.

[0049] [Figure 22B] FIG. 22B is a side view illustrating the two-dimensional scanning light source of FIG. 22A.

[0050] [Diagram 23] FIG. 23 is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror according to some embodiments of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] The present invention generally relates to a method and system related to a projection display system, including a wearable display. More specifically, an embodiment of the present invention provides a method and system for a volumetric display, also called a light field display, which creates a volumetric image of light in more than one depth plane. The present invention is applicable to various applications in computer vision and image display systems.

[0052] 1A is a simplified perspective view illustrating a fiber scanner, according to an embodiment of the present invention. The fiber scanner 100, which may have dimensions of approximately 2 mm×2 mm×7 mm, includes a fiber input 110 and a fiber oscillation region 120. When driven by a piezoelectric actuator (not shown), the optical fiber oscillates within the fiber oscillation region 120, e.g., in a helical configuration, with increasing angular deflection over a given frame time during projection of light. The various elements of the fiber scanner are described more fully throughout this specification.

[0053] FIG 1B is a simplified cutaway perspective view illustrating a fiber scanner according to an embodiment of the present invention. In the view illustrated in FIG 1B, the fiber scanner 100 has been rotated horizontally. The fiber input 110 is illustrated on the right side of the figure and provides input to a fiber oscillating section 120 that includes a piezoelectric actuator 150 supported by a retaining collar 152 (and driven by an electrical signal from a wire, not shown), and a scanning fiber 154 disposed within a mechanical enclosure 156.

[0054] During operation, the scanning fiber 154, which is mechanically attached to the piezoelectric actuator 150, oscillates within the fiber oscillation region 120. In one embodiment, the piezoelectric actuator 150 includes four electrodes distributed at circumferential positions that are offset by 90° relative to one another. Thus, positive and negative voltages applied to opposite sides of the piezoelectric actuator can deflect the scanning fiber in the plane of the actuator and the electrodes. By synchronously driving all four electrodes, oscillation of the fiber can be achieved.

[0055] As described more fully herein, a small form factor comparable to standard eyeglasses is made possible by embodiments of the present invention. By utilizing embodiments of the present invention, displays with desired field of view, depth of resolution, integrated inertial measurement units (IMUs), cameras, audio components, and the like are provided. In some embodiments, the fiber scanner 100 illustrated in FIGS. 1A and 1B is mounted within the temples or frames of eyeglasses and operates in combination with an eyepiece disposed within the frame to direct projected light toward the user's eyes. The size of the fiber scanner 100 allows for the integration of multiple fiber scanners that can direct light toward each eye, increasing the field of view through tiling of the display area. As an example, if two projectors are used per eye, a diagonal field of view of 89° can be provided using two projectors. Using four projectors per eye, a diagonal field of view of 134° can be achieved. In addition to the increased field of view, additional depth planes can be provided through the use of multiple projectors. Additional discussion related to tiling the display area and the use of multiple projectors to increase the field of view is provided in U.S. patent application Ser. No. 15 / 927,821, filed Mar. 21, 2018, the disclosure of which is incorporated by reference in its entirety herein for all purposes.

[0056] In one embodiment, the fiber scanner 100 is fed by a fiber input 110 and the fiber oscillating region 120 is mounted within the outer edge of the frame as illustrated in Figure 2 of U.S. patent application Ser. No. 15 / 927,855, filed Mar. 21, 2018, the disclosure of which is incorporated herein by reference in its entirety for all purposes. Additional description of the fiber scanner is provided in U.S. patent application Ser. No. 15 / 927,765, filed Mar. 21, 2018, the disclosure of which is incorporated herein by reference in its entirety for all purposes.

[0057] FIG. 2A diagrammatically illustrates light paths within a viewing optics assembly (VOA) that may be used to present digital or virtual images to a viewer, according to an embodiment of the present invention. The VOA includes an eyepiece 260 that may be mounted around or in front of the viewer's eye. As discussed herein, the VOA may be integrated with the frames of a pair of eyeglasses to present digital or virtual images to a viewer wearing these eyeglasses. The eyepiece 260 may include one or more eyepiece layers. In one embodiment, the eyepiece 260 includes three eyepiece layers, one eyepiece layer for each of the three primary colors, i.e., red, green, and blue. In another embodiment, the eyepiece 260 may include six eyepiece layers, i.e., one set of eyepiece layers for each of the three primary colors configured to form a virtual image in one depth plane, and another set of eyepiece layers for each of the three primary colors configured to form a virtual image in another depth plane. In other embodiments, the eyepiece 260 may include three or more eyepiece layers, one for each of the three primary colors, for three or more different depth planes. Each eyepiece layer may include a planar waveguide and may include an internal coupling grating 267, an orthogonal pupil expander (OPE) region 268, and an exit pupil expander (EPE) region 269.

[0058] Still referring to FIG. 2A, an input light beam 264 (e.g., provided by fiber scanner 100 as illustrated in FIGS. 1A and 1B) projects image light onto an internal coupling grating 267 in the eyepiece layer 260. The internal coupling grating 267 couples the image light provided by the input light beam 264 into a planar waveguide that propagates in a direction toward an OPE region 268. The waveguide propagates the image light in a horizontal direction by total internal reflection (TIR). The OPE region 268 of the eyepiece layer 260 also includes a diffractive element that couples a portion of the image light propagating in the waveguide and redirects it toward an EPE region 269. The EPE region 269 includes a diffractive element that couples a portion of the image light propagating in the waveguide in a direction substantially perpendicular to the plane of the eyepiece layer 260 and directs it toward the viewer's eye 262. In this manner, the image projected by the input light beam 264 may be viewed by the viewer's eye 262 .

[0059] As described above, the image light generated by the projector may include light of three primary colors, namely, blue (B), green (G), and red (R). Such image light can be separated into its constituent colors, e.g., temporally or spatially, such that the image light in each constituent color can be coupled into separate waveguides in the eyepiece.

[0060] FIG. 2B is a partial cross-sectional view illustrating the structure of an eyepiece according to an embodiment of the present invention. The area shown in the cross-sectional view includes the area of ​​the incoupling diffractive optical element (e.g., an incoupling grating) of the eyepiece 200. As shown in FIG. 2B, the eyepiece 200 includes a stack of waveguide plates 220, 230, and 240 that receive input light from a fiber scanner and output image information to a viewer's eye 202. The eyepiece 200 illustrated in FIG. 2B includes an eye-side cover layer 210 positioned on the side of the eyepiece adjacent to the viewer's eye, and a world-side cover layer 250 positioned on the side of the eyepiece facing toward the world.

[0061] In some embodiments, the waveguide plates 220, 230, and 240 include individual planar waveguides 222, 232, or 242 for propagating light in the plane of the respective waveguide plate 220, 230, and 240. Each planar waveguide 222, 232, or 242 has a back surface facing the viewer's eye and a front surface facing the world. In the embodiment illustrated in FIG. 2B, the waveguide plates 220, 230, and 240 also include individual gratings 224, 234, or 244 disposed on the back surface of the respective waveguide 222, 232, or 242 for coupling and redirecting a portion of the light propagating within the respective waveguide 222, 232, or 242.

[0062] In the illustrated embodiment, each waveguide 222, 232, or 242 and each grating 224, 234, or 244 may be wavelength selective to selectively propagate or redirect light within a given wavelength range. In some embodiments, waveguide plates 220, 230, and 240 may each be configured for a separate primary color. For example, waveguide plate 220 is configured for red (R) light, waveguide plate 230 is configured for green (G) light, and waveguide plate 240 is configured for blue (B) light. It should be understood that eyepiece 200 may include two or more waveguide plates for red light, two or more waveguide plates for green light, and two or more waveguide plates for blue light for different depth planes, as described above. In some other embodiments, other colors, including magenta and cyan, may be used in addition to or to replace one or more of red, green, or blue.

[0063] To improve optical efficiency, some embodiments form a reflective structure behind the input coupling element (e.g., a vertically aligned internal coupling grating) and use a reflective surface, e.g., a surface metallization on one of the surfaces of the eye-side cover layer, e.g., the front surface, to provide a highly reflective surface (e.g., about 100% reflective coating), which reflects the input light, which may be RGB light, passing through the input coupling element and causing a second pass through the input coupling element, improving image brightness. As shown in FIG. 2B, the reflector 212 reflects the input light 201 coming from the fiber scanner that is not coupled into the waveguide. After reflecting from the reflector 212, the input light can make a second pass through the input coupling element, increasing the amount of light coupled into the waveguide.

[0064] In an alternative embodiment, an annular reflector 252, fabricated, for example, using a 100% reflective metal coating, can be placed on the world cover glass. Although this annular reflector 252 is shown on the back side of the world cover layer 250, this is not required by the present invention and may alternatively be mounted on the front side. Those skilled in the art will recognize many variations, modifications, and alternatives. In this alternative embodiment, the input light 201 from the fiber scanner passes through the center of the annular reflector 252 after being output from the optical assembly cross section of the fiber scanner. Because the input light is diverging, the beam spreads as it passes through the eyepiece and reflects off the reflector 212 behind the input coupling element. This reflected light 204 propagates back through the eyepiece and the cone of light expands during propagation. In some embodiments, the reflected light 204 is also coupled into the internal coupling grating during the return path, and is characterized by the same orientation as the input beam for presentation to the viewer, since the reflected light 204 is a mirror image of the input light 201, but incidence through the opposite side of the internal coupling grating results in the same orientation. A substantial portion, which may be a large portion of the light, can reflect off the annular reflector 252 on the world-side cover layer, as illustrated by the doubly reflected light 206, and make a third pass through the input coupling element, resulting in additional coupling of light into the waveguide plate. As will be apparent to one skilled in the art, a hall of mirrors effect can be achieved, resulting in increased brightness correlated with an increased number of light rays passing through the eyepiece, improving fill factor and image quality.

[0065] Channels are cut into the temples and frame to accommodate fiber and electrical wiring. As the fiber / wires pass over the spring hinges, the design dimensions ensure that the fiber is not bent beyond a minimum bend radius as the temples fold.

[0066] In addition to the reflective structures associated with the input coupling element discussed in connection with FIG. 2B, some embodiments utilize a partially reflective (e.g., 50% aluminized) surface on the inner surface of the world-side cover glass so that a portion (e.g., half) of the light propagating from the eyepiece toward the world is reflected and directed toward the user's eye, which increases overall brightness as a result of a slight lateral offset to the beam, increases beam density, and contributes to an improved fill factor.

[0067] Embodiments of the present invention provide improvements over conventional optical configurations. For example, as described in U.S. Patent Application Serial No. 15 / 927,765, a polarizing beam splitter may be utilized as a component of a collimating optical assembly to collimate an input light beam emitted from an optical fiber. However, it may be difficult to produce a polarizing beam splitter that performs well for a wide range of incidence angles. In addition, it may be desirable to have high optical throughput through the polarizing beam splitter, which requires high transmission on the first pass and high reflection on the second pass. For an unpolarized input light beam, approximately 50 percent of the light intensity may be lost on the first pass and another 25 percent of the light intensity may be lost on the second pass. To improve light throughput, it may be desirable to deliver a polarized input light beam using a polarization-maintaining (PM) optical fiber. Some PM optical fibers have stress members to introduce birefringence and promote polarization-maintaining properties. Depending on the etchant used to fabricate the fiber scanner components, the stress members may etch more quickly or more slowly than the fiber core, resulting in challenges associated with the use of PM optical fibers. Thus, some embodiments of the present invention utilize optical waveguides, including optical fibers, that are not polarization maintaining, thereby reducing system complexity and cost.

[0068] Additionally, embodiments of the present invention provide optical configurations that utilize collimating optical elements in an on-axis configuration. As will be apparent to those skilled in the art, it may be desirable to use optical elements in an on-axis configuration, where light is incident on the optical element at an angle that is approximately normal to the surface of the optical element, as opposed to implementations where light is incident on the optical element at an off-axis angle, i.e., a high incidence angle. By utilizing an on-axis configuration, embodiments of the present invention are characterized by a high level of optical performance, as opposed to off-axis configurations, where the optical element may introduce aberrations such as astigmatism and coma.

[0069] FIG. 3 diagrammatically illustrates a fiber scanning projector coupled to an eyepiece according to some embodiments of the present invention. A fiber scanning projector, also referred to as a fiber scanner, is an example of a scanning light source. A fiber scanner can include an optical fiber and a scanning mechanism configured to scan the optical fiber in a linear direction such that a tip of the optical fiber is configured to scan along a trajectory, the trajectory defining a first optical axis. As shown in FIG. 3, the fiber scanning projector can include an optical fiber 310 (or another suitable waveguide scanner). The optical fiber 310 can be deflected such that the trajectory of its tip defines a two-dimensional convex object surface 312 (e.g., a portion of a spherical surface). The optical axis 320 can be defined as a line that passes through the optical fiber 310 when the optical fiber 310 is not deflected. For example, the optical axis 320 can pass through a center of the convex object surface 312. The fiber scanning projector may further include a collimating optical element 330, such as a concave collimating mirror, positioned in an on-axis configuration along the optical axis 320. In this on-axis configuration, the optical axis 320 is aligned with a normal to the center of the collimating optical element 330. As the light exits the tip of the optical fiber 310, the light beam may diverge as a cone of rays (e.g., bounded by marginal rays 360a and 360b, as illustrated in FIG. 3) with a defined angle determined by the numerical aperture of the optical fiber 310. Thus, the collimating optical element 330 may be configured to receive a diverging input light beam characterized by marginal rays 360a and 360b emitted from the tip of the optical fiber 310 and produce a collimated light beam characterized by marginal rays 370a and 370b as a reflected light beam. Although only a single diverging input light beam is illustrated for the undeflected position of the optical fiber, it should be understood that the spatial extent of the collimating optical element 330 will be such that the diverging input light beam produced by the fiber tip across a range of deflection angles will be captured and collimated by the collimating optical element 330.

[0070] 3, the deflection of the optical fiber 310 defines a convex object surface 312. In some embodiments, the collimating optical element 330 may have a reflective surface, which may be a nearly spherical mirror, with a radius of curvature twice that of the convex object surface 312. Thus, in some embodiments, the majority of the focusing is achieved using the collimating optical element 330, which may be implemented as a curved mirror with an aspheric correction term. In alternative embodiments, the reflective surface is characterized by a radius of curvature that is greater than twice that of the scanning surface, i.e., the convex object surface 312.

[0071] In some embodiments, the profile of the reflective surface of the collimating optical element 330 may vary from a curvature of twice the radius of curvature of the convex object surface 312 as a function of, for example, the refractive index of an intermediate component in the optical path (e.g., the refractive index of the waveguide 342) and the angle of incidence, which may accommodate an asymmetric configuration due to the tilt of the waveguide 342 relative to the optical axis 320.

[0072] Referring to FIG. 3, the waveguide 342 and the internally coupled DOE 346 are aligned at an angle θ i As a result, light from the fiber 310 may be incident on the waveguide 342 at various and asymmetric angles. For example, ray 360a has an angle of incidence less than that of ray 360b, i.e., ray 360b is closer to a grazing incidence angle than ray 360a. For purposes of clarity, the light rays propagating through the waveguide 342 are illustrated as not refracted, but in actual practice, differences in the input angles will result in differences in the refraction angles and transmission through the waveguide 342. Thus, in some embodiments, a non-zero angle θ between the normal 302 to the surface of the waveguide 342 and the optical axis 320 may be used. i To compensate for the asymmetry imparted onto the convex object surface 312 after propagation through the waveguide 342, the asymmetry is compensated for by modifying the curvature of the collimating optical element 330. In these embodiments, the curvature or concavity of the collimating optical element 330 is adjusted to compensate for the angle θ i3, as well as a function of the refractive index and thickness of the waveguide 342 and other optical elements through which the diverging beam passes. By varying the curvature of the collimating optical element 330 as a function of position, compensation for the effect of the tilted orientation of the waveguide relative to the optical axis 320 of the optical fiber 310 and any resulting effect on the propagation angle of the light rays emitted by the optical fiber 310 is provided by some embodiments of the present invention.

[0073] 3, an eyepiece 340 may be positioned between the tip of the optical fiber 310 and the collimating optical element 330. The eyepiece 340 is configured such that the normal 302 to the surface of the waveguide 342 is at a non-zero angle θ with respect to the optical axis 320. i The eyepiece 340 may include a planar waveguide 342 tilted relative to the optical axis 320 to form a . The eyepiece 340 may further include an internally coupled diffractive optical element (DOE) 346, e.g., an internally coupled grating (ICG), coupled to a first lateral region of the waveguide 342 that intercepts the optical axis 320.

[0074] The eyepiece 340 may further include an out-coupling diffractive optical element (DOE) 348 (e.g., an out-coupling grating) coupled to a second lateral region of the surface of the waveguide 342 that is displaced a predetermined distance from the first lateral region. The out-coupling DOE 348 may comprise a diffraction grating configured to diffract a portion of the light propagating within the waveguide 342 out of the waveguide 342 toward the viewer's eye 350. For example, the out-coupling DOE 348 may be an exit pupil expander (EPE), discussed above in connection with FIG. 2A. To facilitate the discussion below, as illustrated in FIGS. 3 and 4A-4B, the direction oriented along the plane of the waveguide extending from the in-coupling DOE 346 toward the out-coupling DOE 348 is the "-X" direction, and the opposite direction is the "+X" direction.

[0075] As described more fully below in connection with Figures 4A-4B, light from the optical fiber 310 is incident on the internal coupling DOE 346 at an oblique incidence angle so that the diffractive coupling of the incident light into the waveguide 342 can be controlled to achieve desired diffractive coupling conditions.

[0076] FIG. 4A is a simplified schematic diagram illustrating the diffractive coupling of light for the angled in-coupling DOE 346 as illustrated in FIG. 3, according to an embodiment of the present invention. FIG. 4A diagrammatically illustrates the optical effect of the in-coupling DOE 346 as a diverging input light beam (represented by central ray 360-1) emitted from the tip of the optical fiber 310 is incident on the in-coupling DOE 346 on a first pass. For clarity, only the central ray 360-1 of the diverging input light beam, which is aligned with the optical axis 320, is shown. However, it should be understood that the analysis below is also applicable to other rays of the diverging input light beam. As illustrated in FIG. 4A, the in-coupling DOE 346 diffracts a first portion of the input light beam (in a transmission geometry) (represented by central ray 360-1) as a positive first order ("+1") diffraction 420 at a diffraction angle θ +1 and a second portion of the input light beam (in a transmission geometry) (represented by central ray 360-1) is diffracted as negative first order ("-1") 430 at a diffraction angle θ -1 The central ray 360-1 may be diffracted at a non-zero angle of incidence θ with respect to the normal 302 of the waveguide associated with the in-coupling DOE 346. i θ, the angles of the diffraction orders will not be equal. +1 If is positive, the diffraction angle θ +1 is the diffraction angle θ -1 Therefore, as explained below, the diffracted orders will not undergo uniform total internal reflection within the waveguide.

[0077] The operation of a diffraction grating can be governed by the grating equation: [ka] In the formula, θ m is the diffraction angle of light exiting the grating with respect to a vector normal to the surface of the grating, λ is the wavelength, m is an integer-valued parameter known as the "order", d is the period of the grating, and θ i is the angle of incidence of the light with respect to the vector normal to the surface of the grating. Hence, the diffraction angle θ for a particular order m (where m is nonzero) m is the angle of incidence θ i and the period d of the grating.

[0078] According to some embodiments, the incidence angle θ of the light constituting the diverging input light beam i (determined by the angle at which the waveguide 342 is tilted with respect to the optical axis 320) and the grating period d is the diffraction angle θ +1 While the positive first order diffraction 420 at the diffraction angle θ may satisfy the total internal reflection (TIR) ​​condition of the waveguide 342 and therefore propagate in the +X direction within the waveguide 342, -1 4A ) or may be selected such that the negative first diffraction light 430 at 4A ′ may lack the TIR condition of the waveguide 342 and therefore may either propagate along the surface of the waveguide 342 in the −X direction as an evanescent wave (represented by the long dashed line 430′ in FIG. 4A ) or be refracted out of the waveguide 342 at each bounce within the waveguide 342. The positive first diffraction light 420 propagates in the waveguide 342 away from the out-coupling DOE 348 in the +X direction and therefore will be diffracted out of the waveguide 342 by the out-coupling DOE 348 and will not reach the viewer's eye 350. Rather, a light trap or other light absorbing structure may be utilized as a beam dump to absorb the light that is diffracted into the positive first diffraction light on the first pass.

[0079] Referring again to FIG. 3, a portion of the diverging input light beam, characterized by marginal rays 360a and 360b, emerging from the tip of optical fiber 310 may be transmitted through in-coupling DOE 346 (e.g., as a zero-order transmission) and incident on collimating optical element 330 in an on-axis configuration. Collimating optical element 330 may reflect the diverging input light beam on a second pass as a collimated light beam (e.g., as a bundle of parallel rays bounded by marginal rays 370a and 370b, as illustrated in FIG. 3) that is directed back toward in-coupling DOE 346. As described above, the rays at the edges of the diverging light beam are illustrated by marginal rays 360a and 360b, although other rays will be collimated as well and form the collimated light beam represented by marginal rays 370a and 370b.

[0080] 4B is a simplified schematic diagram illustrating the diffractive coupling of a collimated light beam illustrated by central ray 370-1 for an angled in-coupling DOE 346 as illustrated in FIG. 3, in accordance with an embodiment of the present invention. For clarity, only the central ray 370-1 of the collimated light beam is shown. However, it should be understood that the analysis below is also applicable to other rays of the collimated input light beam. As illustrated in FIG. 4B, the in-coupling DOE 346 diffracts a first portion of the collimated light beam illustrated by central ray 370-1 (in a reflecting geometry) as a positive first order ("+1") diffraction 460 at a diffraction angle θ +1 , a second portion of the collimated light beam illustrated by central ray 370-1 (in the reflection geometry) is diffracted as negative first order ("-1") 470 at a diffraction angle θ -1 It can be diffracted by

[0081] As discussed in connection with light incident on the incoupling DOE during a first pass before collimation, the central ray 370-1 of the collimated light beam is incident at a non-zero angle of incidence θ with respect to the normal 302 of the waveguide associated with the incoupling DOE 346. iθ, the angles of the diffraction orders will not be equal. +1 If is positive, the diffraction angle θ +1 is the diffraction angle θ -1 Therefore, as explained below, the diffracted orders will not undergo uniform total internal reflection within the waveguide.

[0082] Referring to FIG. 4B, since the central ray 370-1 of the collimated light beam is incident on the internally coupled DOE 346 from an opposite direction compared to the central ray 360-1 of the input light beam 360 shown in FIG. 4A, the positive first order diffraction 460 may satisfy the TIR condition of the waveguide 342 and thus propagate in the −X direction within the waveguide 342, while the negative first order diffraction 470 may lack the TIR condition of the waveguide 342 and thus either propagate in the +X direction along the surface of the waveguide 342 as an evanescent wave (represented by the long dashed line 470′ in FIG. 4B) or be refracted out of the waveguide 342 at each bounce within the waveguide 342. The positive first order diffraction 460 propagates along the −X direction within the waveguide 342 towards the out-coupling DOE 348 and may be diffracted out of the waveguide 342 by the out-coupling DOE 348 to reach the viewer's eye 350 .

[0083] As described above, by taking advantage of the asymmetric behavior of the in-coupling DOE 346 and the waveguide 342 in the angled configuration of the eyepiece 340 for the fiber scanning projector, efficient coupling of the input light beam emitted from the optical fiber 310 into the waveguide 342 can be achieved using the on-axis collimating optical element 330. This optical configuration avoids the use of a polarizing beam splitter, as discussed in U.S. Patent Application No. 15 / 927,765. Thus, a non-polarized input light beam can be transmitted by using a non-polarization-maintaining optical fiber, which can eliminate one or more technical difficulties associated with conventional techniques. The fiber scanning projector illustrated in FIG. 3 can also have the advantage of having fewer optical components compared to configurations using polarizing beam splitters, and therefore can be easier to manufacture. The on-axis configuration of the collimating optical element 330 can prevent off-axis aberrations, such as astigmatism and coma, which can be difficult to correct in a single-element collimating optical element 330.

[0084] In some embodiments, the incoupling DOE 346 may be blazed (i.e., given a particular periodic profile) to preferentially diffract light into desired diffraction orders. For example, the incoupling DOE 346 may be blazed such that the intensity of the positive first diffraction order 460 may be higher than the intensity of the negative first diffraction order 470 to maximize the percentage of the input light beam that reaches the viewer's eye 350.

[0085] Additionally, the in-coupling DOE 346 may be configured to have a higher efficiency in the reflected order than in the transmitted order such that the in-coupling DOE 346 may have a higher coupling efficiency as the input light beam incident on the in-coupling DOE 346 on a second pass than as the input light beam incident on the in-coupling DOE 346 on a first pass. Thus, a smaller percentage of the input light beam may be wasted on the first pass, resulting in a larger percentage of the input light beam reaching the viewer's eye 350.

[0086] The periodic structure of the internally coupled DOE 346 may include a surface relief profile or volumetric modulation of the refractive index of a transparent material according to various embodiments. In some embodiments, the internally coupled DOE 346 may include a metasurface. A metasurface is an optically thin sub-wavelength structured interface. Metasurfaces are generally created by assembling an array of small anisotropic light scatterers (i.e., resonators such as optical antennas). The spacing between the antennas and their dimensions are much smaller than the wavelength. From Huygens' principle, metasurfaces can mold an optical wavefront into an arbitrary shape with sub-wavelength resolution by introducing spatial variations into the optical response of the light scatterers. Metasurfaces may allow for control of the polarization, phase, and amplitude of light. Factors that can be used to manipulate the wavefront of light include the material, size, geometry, and orientation of the nanostructures. The resonant wavelength of a metasurface can be engineered by varying the geometric size of its constituent nanostructures, thereby providing wavelength selectivity. For example, metasurfaces may be engineered to be highly wavelength selective in redirecting light. Thus, metasurfaces can be used as wavelength-selective incoupling and outcoupling optical elements. Additional description of metasurface diffractive optical elements is provided in U.S. patent application Ser. No. 15 / 683,644, filed Aug. 22, 2017, the disclosure of which is incorporated by reference in its entirety herein for all purposes.

[0087] FIG. 5 diagrammatically illustrates a fiber scanning projector coupled to an eyepiece 540 according to some other embodiments of the present invention. The eyepiece 540 includes a planar waveguide 542, an in-coupled DOE 546 coupled to a first lateral region of a back surface of the waveguide 542, and an out-coupled DOE 548 coupled to a second lateral region of the waveguide 542. Note that the out-coupled DOE 548 is illustrated in FIG. 5 as being coupled to the back surface of the waveguide 542, but can be coupled to either the front or back surface. The back surface of the in-coupled DOE 546 is metallized so that the in-coupled DOE 546 can operate in a reflective geometry. In general, a metallized in-coupled DOE can have a higher coupling efficiency than a non-metallized in-coupled DOE. The out-coupling DOE 548 may comprise a diffraction grating (which may be referred to herein as an out-coupling grating) configured to diffract a portion of the light propagating within the waveguide 542 out of the waveguide 542 toward the viewer's eye 550. To facilitate the discussion below, as illustrated in Figures 5 and 6A-6B, the direction extending from the in-coupling DOE 546 toward the out-coupling DOE 548 is designated the "-X" direction, and the opposite direction is designated the "+X" direction.

[0088] The fiber scanning projector includes an optical fiber 510 (or another suitable waveguide scanner). The optical fiber 510 may be deflected such that the trajectory 512 of its tip defines a two-dimensional convex object surface (e.g., a portion of a spherical surface). An optical axis 520 may be defined as a line that passes through the optical fiber 510 when the optical fiber 510 is not deflected. For example, the optical axis 520 may pass through the center of the convex object surface. The optical fiber 510 is deflected such that the optical axis 520 is at a non-zero angle θ with respect to a normal 502 to the waveguide 542. i 6A-6B , light from optical fiber 510 is incident on the in-coupling DOE 546 at an oblique incidence angle so that the diffractive coupling of the incident light into waveguide 542 can be controlled to achieve desired diffractive coupling conditions.

[0089] Because the in-coupling DOE 546 is metallized, a portion of the input light beam 560 may be reflected by the in-coupling DOE 546 on the first pass (e.g., as a zero-order reflection) and appear as a diverging input light beam emanating from the virtual object point 590. As described below in connection with FIG. 6A, the in-coupling DOE 546 will also diffract the input light beam 560 into other diffraction orders (e.g., positive and negative first diffraction orders).

[0090] The fiber scanning projector may further include a collimating optical element 530, such as a concave mirror, positioned on the same side of the eyepiece 540 as the optical fiber 510. The collimating optical element 530 is positioned in an on-axis configuration and receives a diverging input light beam 560' (i.e., zero-order reflection) reflected by the metallized in-coupled DOE 546. The collimating optical element 530 collimates the input light beam as a collimated reflected light beam 570 that is directed back toward the in-coupled DOE 546 on a second pass.

[0091] 6A is a simplified schematic diagram illustrating the diffractive coupling of light for an angled in-coupling DOE 546 as shown in FIG. 5, in accordance with an embodiment of the present invention. For clarity, only the central ray 560-1 of the diverging beam 560 is shown. As shown, the in-coupling DOE 546 diffracts a first portion of the input light beam 560 (in a reflecting geometry) as a positive first order ("+1") diffraction 620 at a diffraction angle θ +1 , and a second portion of the input light beam 560 (in the reflection geometry) is diffracted as a negative first order ("-1") 630 at a diffraction angle θ -1 Similar to the internally coupled DOE 346 illustrated in FIGS. 3 and 4A-4B, the incident angle θ i and the grating period d of the internally coupled DOE 546 is the diffraction angle θ -1 While the negative first order diffraction 630 at the diffraction angle θ +16A ) may be selected such that the positive first order diffraction 620 at may lack the TIR condition of the waveguide 542 and therefore may either propagate along the surface of the waveguide 542 in the −X direction as an evanescent wave (represented by the long dashed line 620′ in FIG. 6A ) or be refracted out of the waveguide 542 at each bounce within the waveguide 542. Thus, the incidence angle θ of the in-coupled DOE 546 i and the selection of the grating period d may result in little or no light being diffracted into the first positive order reflection 620 that reaches the out-coupling DOE 548. The negative first order diffraction 630 propagates in the +X direction within the waveguide 542 away from the out-coupling DOE 548 and therefore cannot be diffracted out of the waveguide 542 by the out-coupling DOE 548 and reach the viewer's eye 550, as illustrated in Figure 5. Rather, a light trap or other light absorbing structure may be utilized as a beam dump to absorb the light that is diffracted into the negative first order reflection 630 on the first pass.

[0092] 6B is a simplified schematic diagram illustrating the diffractive coupling of a collimated light beam 570 for an angled in-coupling DOE 546 as illustrated in FIG. 5, according to an embodiment of the present invention. For clarity, only a central ray 570-1 of the collimated light beam 570 is shown. However, it should be understood that the analysis below is also applicable to other rays of the collimated input light beam 570. As shown, the in-coupling DOE 546 may diffract a first portion of the collimated light beam 570 (in a reflection geometry) as a positive first order ("+1") diffracted light beam 660 and a second portion of the collimated light beam 650 (in a reflection geometry) as a negative first order ("-1") diffracted light beam 670. Here, the collimated light beam 570 is incident on the internally coupled DOE 546 from an opposite direction compared to the input light beam 560 shown in FIG. 6A, so that the negative first order diffracted light beam 670 may satisfy the TIR condition of the waveguide 542 as shown in FIG. 6B and thus propagate in the −X direction within the waveguide 542, while the positive first order diffracted light beam 660 may lack the TIR condition of the waveguide 542 and thus either propagate in the +X direction along the surface of the waveguide 542 as an evanescent wave (represented by the long dashed line 660′ in FIG. 6B) or be refracted out of the waveguide 542 at each bounce within the waveguide 542. The negative first order diffracted light beam 670 propagates within the waveguide 542 along the −X direction towards the out-coupling DOE 548 and may be diffracted out of the waveguide 542 by the out-coupling DOE 548 to reach the viewer's eye 550.

[0093] The angle θ between the optical axis 520 and the normal 502 of the waveguide 542 i may be selected to promote asymmetric behavior of the in-coupled DOE 546 and the waveguide 542, as described above. Other geometric considerations may also be taken into account. For example, the angle θ i may be selected to avoid any conflict between the trajectory 512 of the tip of the optical fiber 510 and the collimating optical element 530. In various embodiments, the angle θ imay be selected to be, for example, 15°, 20°, 25°, 30°, 35°, 40°, or 45°. In some other embodiments, the collimating optical element 530 may have a hole through which the optical fiber 510 may pass, similar to the configuration illustrated in FIG. 5 of U.S. Patent Application No. 15 / 927,765. This configuration is similar to the configuration illustrated in FIG. 5 of U.S. Patent Application No. 15 / 927,765, where the angle θ i may be used when the optical fiber 510 is selected such that it would otherwise be in geometric conflict with the collimating optical element 530 .

[0094] FIG. 7 diagrammatically illustrates a fiber scanning projector coupled to an eyepiece 740 according to some further embodiments of the present invention. Similar to eyepiece 540, eyepiece 740 includes a planar waveguide 742, an internally coupled DOE 746 coupled to a first lateral region of the back surface of waveguide 742, and an externally coupled DOE 748 coupled to a second lateral region of waveguide 742 (the externally coupled DOE 748 is illustrated in FIG. 7 as being coupled to the back surface of waveguide 742, but can be coupled to either the front or back surface). Externally coupled DOE 748 may comprise a diffraction grating (which may be referred to herein as an externally coupled grating) configured to diffract a portion of the light propagating within waveguide 742 out of waveguide 742 towards a viewer's eye 750. Here, the back surface of internally coupled DOE 746 is not metallized. Instead, the eyepiece 740 includes a separate plane mirror 780 positioned behind the in-coupling DOE 746 .

[0095] The fiber scanning projector includes an optical fiber 710 (or waveguide). The optical fiber 710 may be deflected such that the trajectory of its tip defines a two-dimensional convex object surface 712 (e.g., a portion of a spherical surface). The optical axis 520 may be defined as a line that passes through the optical fiber 710 when the optical fiber 710 is not deflected. For example, the optical axis 720 may pass through the center of the convex object surface 712. The optical fiber 710 is oriented such that the optical axis 720 is at a non-zero angle θ with respect to the normal 702 of the waveguide 742. iA portion of the input light beam 760 may pass through the in-coupled DOE 746 on a first pass and be reflected by the planar mirror 780. Thus, the input light beam 760 may appear as a diverging input light beam emanating from a virtual object point 790.

[0096] The fiber scanning projector may further include a collimating optical element 730, such as a concave mirror, positioned on the same side of the eyepiece 740 as the optical fiber 710. The collimating optical element 730 is positioned in an on-axis configuration and receives a diverging input light beam 760. The collimating optical element 730 reflects the input light beam 760 on a second pass as a collimated light beam 770 that is directed back towards the in-coupled DOE 746.

[0097] Similar to the fiber scanning projector shown in FIG. 5, the incidence angle θ i and the grating period d may be selected such that for an input light beam 760 incident on the in-coupling DOE 746 on a first pass, the negative first order diffraction (in a reflection geometry) may satisfy the TIR condition of the waveguide 742, while the positive first order diffraction (in a reflection geometry) may miss the TIR condition of the waveguide 742, similar to the illustration in Figure 6A. For a collimated light beam 770 incident on the in-coupling DOE 746 on a second pass, the negative first order diffraction (in a reflection geometry) may satisfy the TIR condition of the waveguide 742, while the positive first order diffraction (in a reflection geometry) may miss the TIR condition of the waveguide 742, similar to the illustration in Figure 6B.

[0098] In general, the eyepiece may include an externally coupled DOE (e.g., externally coupled DOE 548 shown in FIG. 5 or externally coupled DOE 748 shown in FIG. 7) that is configured to have the same lattice parameters, including periodicity, as the internally coupled DOE (e.g., internally coupled DOE 546 shown in FIG. 5 or internally coupled DOE 746 shown in FIG. 7). For example, in the system illustrated in FIGS. 5 and 6A-6B and replicated in FIG. 8, an incident angle θ on waveguide 542 may be used. i 6B , the diffracted light beam 670 may propagate within the waveguide 542 towards the out-coupling DOE 548 as a negative first order diffraction caused by the metallized in-coupling DOE 546 when the collimated light beam 570 is incident thereon during the second pass. If the out-coupling DOE 548 is configured to have the same lattice parameters (e.g., have the same lattice period d) as the in-coupling DOE 546, the out-coupling DOE 548 may diffract a portion of the light beam 670 at an output angle θ , for example, as a negative first order diffraction. e 550 toward the viewer's eye 550, and e is the angle of incidence θ i Thus, for an angled configuration of the fiber scanning projector relative to the eyepiece 540 as illustrated in FIG. 5 (or as illustrated in FIGS. 3 and 7), the light field projected to the eye 550 may only cover a certain angular field of view (FOV) that is biased on one side of the normal 504.

[0099] According to other embodiments of the invention, the eyepiece may be implemented in such a manner that the out-coupling DOE 548 has a different grating period d than the grating period of the in-coupling DOE 546. This may allow the out-coupling DOE 548 to diffract light at an angle different from the angle diffracted by the in-coupling DOE 546.

[0100] According to some embodiments, two fiber scanning projectors may be used to cover the FOV on both sides of the normal. FIG. 9 diagrammatically illustrates an example configuration including two fiber scanning projectors. The eyepiece 940 may include a waveguide 942, a first in-coupled DOE 946 coupled to a first lateral region of the right waveguide 942, a second in-coupled DOE 944 coupled to a second lateral region of the left waveguide 942, and an out-coupled DOE 948 (e.g., EPE) coupled to a third lateral region of the central waveguide 942. The first fiber scanning projector may include a first optical fiber 910 and a first collimating optical element 930 arranged in an angled configuration with respect to the eyepiece 940 near the first in-coupled DOE 946, similar to that illustrated in FIG. 5. The second fiber scanning projector may include a second optical fiber 920 and a second collimating optical element 932 arranged in a similarly angled configuration relative to the eyepiece 940 near the second internally coupled DOE 944 as a mirror image of the first fiber scanning projector.

[0101] As shown, a first fiber scanning projector may project a light field in a first angle FOV 980 to the left of the normal 904, while a second fiber scanning projector may be configured to project a light field in a second angle FOV 970 to the right of the normal 904. The first FOV 980 and the second FOV 970 may represent two portions of an image tiled relative to one another. In some embodiments, the first FOV 980 and the second FOV 970 may abut one another near the normal 904 (i.e., the gap 990 between the first FOV 980 and the second FOV 970 substantially disappears) to form a combined FOV that represents a persistent image. It may be necessary to ensure that no residual image is created in the area where the first FOV 980 and the second FOV 970 meet.

[0102] 10 diagrammatically illustrates a top view of a wearable display, according to some embodiments. The wearable display includes a first eyepiece 1030 for a viewer's right eye 1010 and a second eyepiece 1050 for the viewer's left eye 1020. The first eyepiece 1030 and the second eyepiece 1050 may be positioned within goggles, which may be worn around the viewer's face.

[0103] The first eyepiece 1030 may include a first planar waveguide 1032 and a first inwardly coupled DOE 1034 and a first outwardly coupled DOE 1036 coupled to the first waveguide 1032. The first fiber scanning projector may include a first optical fiber 1040 and a first collimating optical element 1042 coupled to the first eyepiece 1030 in an angled configuration similar to that illustrated in FIG. 5 or 7. Similarly, the second eyepiece 1050 may include a second planar waveguide 1052 and a second inwardly coupled DOE 1054 and a second outwardly coupled DOE 1056 coupled to the second waveguide 1052. The second fiber scanning projector may include a second optical fiber 1060 and a second collimating optical element 1062 coupled to a second eyepiece 1050 in an angled configuration.

[0104] It may be preferable to have eyepieces 1030 and 1050 with finite wrap angles, as compared to linear wrap angles, around the viewer's eyes 1010 and 1020. As illustrated in FIG. 10, a first eyepiece 1030 may be wrapped around the viewer's face such that a finite wrap angle β exists between a normal 1038 of the first waveguide 1032 and the viewer's sagittal plane 1012. Similarly, a second eyepiece 1050 may be wrapped around the viewer's face such that a finite wrap angle β exists between a normal 1058 of the second waveguide 1052 and the viewer's sagittal plane 1022. (Note that the illustration in FIG. 10 may be somewhat exaggerated.) According to some embodiments, the wrap angle β may substantially match the inclination angle θ of the first optical fiber 1040 relative to the first waveguide 1032 or the inclination angle θ of the second optical fiber 1060 relative to the second waveguide 1052. Thus, the light field projected by each of the first eyepiece 1030 and the second eyepiece 1050 may cover the FOV, including the normal incident on each respective eye 1010 or 1020. In some other embodiments, the wrap angle β may be less than the inclination angle θ of the optical fiber 1040 or 1060, such that the wrap angle has a more gradual wrap angle. By positioning the first eyepiece 1030 and the second eyepiece 1050 at a finite wrap angle β, a viewer may have a more immersive experience with the virtual content compared to a straight wrap angle (e.g., β=0).

[0105] FIG. 11 diagrammatically illustrates a fiber scanning projector coupled to an eyepiece 1140 according to some further embodiments of the present invention. The eyepiece 1140 may include a waveguide 1142 and a metallized, in-coupled DOE 1146 coupled to a lateral region of the waveguide 1142. The fiber scanning projector may include an optical fiber 1110 (or another suitable waveguide scanner). The optical fiber 1110 may be deflected such that the trajectory of its tip defines a two-dimensional convex object surface 1112 (e.g., a portion of a spherical surface). The fiber scanning projector may further include a solid "prism" 1130. The prism 1130 may include a first curved surface 1132 that may serve as an input surface for receiving an input light beam 1160 emitted from the tip of the optical fiber 1110. Prism 1130 may further include a second surface 1134 that may serve as an output surface for transmitting input light beam 1160. Prism 1130 may further include a third curved surface 1136. The third curved surface 1136 may have a reflective coating, e.g., a metallic coating, and may serve as a collimating mirror, similar to collimating optical elements 530 or 730 as illustrated in Figures 5 and 7, respectively.

[0106] In some embodiments, the first curved surface 1132 may be characterized by a refractive power, similar to the polarizing beam splitter described in U.S. Patent Application Serial No. 15 / 927,765. In some other embodiments, the first curved surface 1132 may be a portion of a spherical surface that substantially matches the object surface 1112. Thus, the light beam 1160 emitted from the tip of the optical fiber 1110 may be normally incident on the first curved surface 1132. The second surface 1134 may also be characterized by a refractive power. In some other embodiments, the second surface 1134 may be substantially flat and may be in physical contact with the waveguide 1142. The prism 1130 may include a material with a refractive index that substantially matches the refractive index of the waveguide 1142, such that light rays exiting the second surface 1134 may not be refracted or may experience negligible refraction. It should be noted that some embodiments utilizing prism 1130 as illustrated in FIG. 11 may benefit from a refractive index of the prism greater than 1, resulting in the angle at which light refracts within the prism being less than the angle at which the light is incident on the prism.

[0107] The methods described above in connection with FIGS. 3-11 can be used in a waveguide display system including a scanning mirror as described more fully below. Such a waveguide display system can be used in a wearable display system such as virtual reality or augmented reality glasses. In some embodiments, the waveguide display system may include an eyepiece waveguide, which may have a first surface and a second surface, and the waveguide includes an in-coupling diffractive optical element (DOE), e.g., an in-coupling grating (ICG), and an out-coupling DOE, e.g., an out-coupling grating (OCG). The waveguide display system may include a first light beam, e.g., an incident light beam, passing through the eyepiece waveguide and reaching a first reflective optical element. The first reflective optical element can be a scanning mirror, a collimating mirror, or a scanning collimating mirror. A second light beam, which is a light beam reflected from the first reflective optical element, may be in-coupled into the waveguide to form an image that can be viewed by a user. In this case, the in-coupling DOE is configured to prevent or inhibit the propagation of the first light beam to the out-coupling DOE in the waveguide through total internal reflection (TIR), and the in-coupling grating is also configured to propagate the second light beam to the out-coupling DOE in the waveguide through TIR.

[0108] As explained above, the angle of incidence and the period or pitch of the grating can be selected to determine the diffraction angle. The in-coupling DOE can be configured such that a first light beam transmitted through the in-coupling DOE does not satisfy the TIR condition for the first light beam to propagate to the out-coupling DOE. Similarly, the in-coupling DOE can be configured such that a second light beam reaching the in-coupling DOE satisfies the TIR condition, and therefore the second light beam can propagate to the out-coupling DOE.

[0109] In an embodiment, the first or incident light beam can be a non-scanned collimated image beam and the first reflective optical element can be a scanning mirror. The reflected scanned beam can be incoupled into a waveguide for imaging.

[0110] In another embodiment, the first or incident light beam may be a diverging light beam provided by a fiber scanner, and the first reflective optical element may be a collimated scanning mirror. For example, the collimated scanning mirror may be a scanning mirror having a reflective optical element with positive refractive power, e.g., a concave mirror. The collimated reflected scanned beam may be in-coupled into a waveguide to form an image.

[0111] In another embodiment, the first or incident light beam may be a collimated light beam provided by a collimating mirror, and the first reflective optical element may be a non-collimated scanning mirror. For example, the collimating mirror may be a segment or piece of a concave reflective optical element with positive refractive power, e.g., a concave mirror. The collimating mirror may be configured to receive the input light beam from a fiber scanner. The reflected scanned beam from the first reflective optical element may be in-coupled into a waveguide to form an image.

[0112] In another embodiment, the first or incident light beam may be a scanned diverging light beam provided by a scanning mirror that receives an input light beam from a fiber scanner and provides a scanned diverging light beam that is transmitted through a waveguide and reaches a first reflective optical element. The first reflective optical element can be a collimating mirror configured to receive the scanned diverging light beam and provide a reflected collimated light beam to the waveguide. The reflected scanned beam from the first reflective optical element can be in-coupled into the waveguide to form an image.

[0113] In some embodiments, the fiber scanner may be disposed on the opposite side of the waveguide to the scanning mirror. In this case, the light beam from the fiber scanner must pass through the waveguide. To prevent the light beam from the fiber scanner from being inwardly coupled into the waveguide and reaching the outwardly coupled DOE, the fiber scanner may be disposed such that the light beam transmits through the waveguide in a portion of the waveguide that does not have an inwardly coupled DOE. Alternatively, the inwardly coupled DOE may be configured such that the light beam from the fiber scanner transmitting through the inwardly coupled DOE does not satisfy the TIR condition because the first light beam does not propagate to the outwardly coupled DOE.

[0114] In the above embodiment, the waveguide display system includes an incident light beam that passes through an eyepiece waveguide and reaches a first reflective optical component. The reflected light beam may be internally coupled into the waveguide to form an image that may be viewed by a user. In an alternative embodiment, the first reflected light beam may pass through a waveguide and reach a second reflective optical component that may provide a second reflected light beam to be internally coupled into the waveguide. In this case, the internal coupling grating is configured to prevent the first light beam or the first reflected light beam from propagating through total internal reflection (TIR) ​​to an output grating in the waveguide. The internal coupling grating is also configured to propagate the second reflected light beam through total internal reflection (TIR) ​​to an output grating in the waveguide.

[0115] For example, in an embodiment, the incident light beam may be a diverging light beam from a fiber scanner that is not incoupling into the waveguide to the outcoupling DOE but transmits through the waveguide. The first reflective optical component can be a scanning mirror that receives the incident light beam from the fiber scanner and provides a first reflected light beam that is a scanned diverging light beam that transmits through the waveguide and reaches the second reflective optical element. The second reflective optical element can be a collimating mirror configured to receive the scanned diverging light beam and provide a second reflected light beam that is a reflected collimated light beam to the waveguide. The second reflected light beam can be incoupling into the waveguide to form an image.

[0116] FIG. 12A is a simplified schematic diagram illustrating a waveguide display system including a projector integrated with a scanning mirror according to some embodiments of the present invention. As shown in FIG. 12A, the waveguide display system 1200 includes an eyepiece waveguide 1240 having a planar waveguide 1242. A non-scanning input light beam 1210, such as emitted from a liquid crystal on silicon (LCOS) projector, is incident on the eyepiece 1240. The eyepiece 1240 includes the waveguide 1242, an internally coupled diffractive optical element (DOE) 1246 coupled to a first lateral region of the waveguide 1242, and an externally coupled DOE 1248, such as an exit pupil expander (EPE) or an external coupling grating (OCG), coupled to a second lateral region of the waveguide 1242. For example, the DOE 1248 can be an exit pupil expander (EPE), such as an external coupling grating (OCG). The display system includes a scanning mirror 1230 positioned on the opposite side of the eyepiece 1240 from the input light beam 1210. The scanning mirror 1230 may be scanned about a scan axis perpendicular to the plane of the paper. The scanning mirror 1230 may be positioned flat against the eyepiece 1240, and the mirror may be placed close to the eyepiece to be as compact as possible, possibly considering the smallest possible scan angle range.

[0117] In the system of FIG. 12A, the scanned reflected light beam from the scanning mirror 1230 is incoupling into the waveguide by the incoupling DOE 1246 and propagates by TIR to the OCG to provide an image viewable by a user. In this configuration, it is desirable to prevent the input light beam 1210 from being coupled by TIR, effectively in the waveguide 1242, into the EPE or OCG region of the eyepiece 1240 (i.e., the second lateral region to which the DOE 1248 is coupled). In some embodiments, the input light beam 1210 can be a polarized collimated light beam and the incoupling DOE 1246 can be a polarization sensitive incoupling grating such that the input light beam 1210 is not coupled into the waveguide. Additionally, the system may include a quarter-wave plate 1232 between the waveguide 1242 and the scanning mirror 1230 such that the scanned reflected light beam has a different polarization than the polarization of the input light beam 1210 and may be internally coupled into the waveguide by TIR to form an output image for the user's eye 1270.

[0118] In some embodiments, an alternative system can be provided without a polarization-sensitive grating or beam splitter and quarter-wave plate. In these embodiments, the angle of incidence of the light beam and / or the period or pitch of the grating can be selected to prevent the incident light beam from propagating to the output grating in the waveguide through total internal reflection (TIR). The angle of incidence of the light beam and / or the period or pitch of the grating can also be configured to propagate the reflected light beam to the output grating in the waveguide through total internal reflection (TIR). An example is illustrated in FIG. 12B.

[0119] 12B is a simplified schematic diagram illustrating a waveguide display system including a projector integrated with a scanning mirror according to some embodiments of the present invention. As shown in FIG. 12B, the waveguide display system 1250 includes an eyepiece waveguide 1242 having a first surface 1221 and a second surface 1222. The waveguide 1242 includes an inward coupling diffractive element (DOE) 1246, which may be an inward coupling grating (ICG), and an outward coupling diffractive element (DOE) 1248, which may be an outward coupling grating (OCG) or an exit pupil expander (EPE).

[0120] The collimated light beam 1211 is projected onto a first surface 1221 of the waveguide 1242 at a first angle of incidence θ. A scanning mirror 1230 is disposed adjacent to a second surface 1222 of the waveguide 1242. The scanning mirror receives the collimated input light beam 1210 and projects a collimated reflected light beam 1220 towards the waveguide at a second angle of incidence θ. r 12. The reflected light beam 1250 may span a range of incidence angles, with dotted lines marking marginal light rays. Because the collimated light beam 1211 is incident on the in-coupling DOE 1246 at an oblique incidence angle, the diffractive coupling of the incident light into the waveguide 1242 can be controlled to achieve a desired diffractive coupling condition. For ease of discussion, the direction oriented along the plane of the waveguide extending from the in-coupling DOE 1246 towards the out-coupling DOE 1248 is the "-X" direction, and the opposite direction is the "+X" direction.

[0121] As shown in FIG. 12B , the input light beam 1210 is incident on the eyepiece 1240 off-axis, e.g., at an angle θ, with respect to the normal 1202 of the waveguide 1242. The collimated light beam 1211 is incident on the in-coupling DOE 1246 at an oblique incidence angle, so that the diffractive coupling of the incident light into the waveguide 1242 can be controlled to achieve a desired diffractive coupling condition. For example, the incidence angle θ and the grating period d of the in-coupling DOE 1246 may be selected to achieve a desired diffractive coupling condition. In some embodiments, the in-coupling DOE 1246 is configured to prevent the collimated input light beam from the collimated light source from propagating in the waveguide to the out-coupling DOE 1248 through total internal reflection (TIR) ​​and to propagate the reflected light beam 1220 collimated in the waveguide to the out-coupling DOE 1248 through total internal reflection (TIR).

[0122] For example, when a collimated light beam 1211 passes through the in-coupling DOE 1246, the negative first order diffraction by the in-coupling DOE 1246 at a diffraction angle θ on the first pass (in a reflection geometry) may lack the TIR condition of the waveguide 1242 toward the out-coupling DOE in the “−X” direction. In FIG. 12B, lacking the TIR condition, the light beam propagates along the surface of the waveguide 1242 as an evanescent wave 1262 or is refracted out of the waveguide 1242 at each bounce within the waveguide 1242, as shown by the dotted line 1264. However, after the input light beam 1210 is reflected by the scanning mirror 1230, when the scanned reflected light beam 1220 is incident on the in-coupled DOE 1246, the negative first order diffraction by the in-coupled DOE 1246 (in a transmission geometry) may satisfy the TIR condition of the waveguide 1242 toward the out-coupled DOE 1248 in the "-X" direction, as shown by light beam 1266. To illustrate the light path for image projection, the light beams that are diffracted in the waveguide and emitted to reach the viewer's eye 1270 are marked by grey arrows 1271, 1272, 1273, and 1274. To simplify the drawing, the light beams in the "-X" direction away from the out-coupled DOE 1248 are omitted in FIG. 12B. Further details on the selective diffraction function of the in-coupled DOE are described above in connection with FIGS. 3, 4A, and 4B.

[0123] The scanning mirror 1230 can be a MEMS (microelectromechanical system) two-axis scanning mirror, which is a two-dimensional scanning mirror configured to rotate in two dimensions with a pitch axis and a roll axis. Depending on the embodiment, the scanning mirror may be driven by a magnetic, electric, or piezoelectric actuator. The movement of the scanning mirror can be resonant in one degree of freedom and quasi-statically controlled in a second degree of freedom. For example, the resonant axis can correspond to a movement similar to a movement along a line of the display, and the quasi-statically controlled second degree of freedom can correspond to a movement similar to a vertical movement between the lines of the display. In one possible case, the resonant axis can be the pitch axis and the quasi-statically controlled axis can be the yaw axis. For a relatively high resolution image, it is desirable to have the equivalent of, for example, 1,000 or 2,000 scan lines and a frame refresh rate of 30 to 60 frames per second. Such parameters call for a line rate of 30 Khz to 120 KHz. For miniature MEMS scanners, small enough to be included within an augmented reality wearable, there is generally a trade-off between the angular range of the resonant axis related to the field of view (FOV) and the resonant frequency compatible with the line rate.

[0124] FIG. 12B illustrates an example of a waveguide display system with a light source providing collimated image light integrated with a scanning mirror. The system allows the light source and the scanning mirror to be placed on opposite sides of the eyepiece waveguide. One advantage of this configuration is the reduced size of the device. Furthermore, this configuration can be implemented without polarization-sensitive DOEs, waveplates for modifying polarization, or polarization-dependent light sources, etc. The complexity and cost of the display system can be substantially reduced.

[0125] In some embodiments, a diverging light source and a collimating optical element can be placed on opposite sides of the waveguide. For example, the incident light beam can be a diverging light beam provided by a fiber scanner, and the collimating scanning mirror can be a scanning mirror, e.g., a scanning concave mirror, having a reflective optical element with positive refractive power. The incidence angle of the light beam and / or the period (or pitch) of the in-coupling DOE can be selected to prevent the incident light beam from propagating to the output grating in the waveguide through total internal reflection (TIR). The incidence angle of the light beam and / or the period or pitch of the grating can also be configured to propagate the collimated scanned reflected light beam in the waveguide through total internal reflection (TIR) ​​to the out-coupling DOE to form an image that can be viewed by a user. An example is illustrated in FIG. 13.

[0126] FIG. 13 is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror, according to some embodiments of the present invention. As shown in FIG. 13, the waveguide display system 1300 includes an eyepiece waveguide 1340 having a planar waveguide 1342 with a first surface 1321 and a second surface 1322. The eyepiece waveguide 1340 also has an internally coupled diffractive optical element (DOE) 1346 coupled to a first lateral region of the waveguide 1342 and an externally coupled DOE 1348 coupled to a second lateral region of the waveguide 1342. A fiber scanner 1315 is disposed adjacent to the first surface 1321 of the waveguide 1342. A collimating scanning optical element, for example a collimating scanning mirror 1330, is disposed adjacent to the second surface of the waveguide. The configuration of the fiber scanner, waveguide, and collimating mirror in Figure 13 may be similar to the configuration of the corresponding components as shown in Figure 3. However, in the waveguide display system 1300, the fiber scanner 1315 is configured to be a line scanner, i.e., with one scan axis, and the collimating mirror 1330 is a scanning mirror configured to scan with one scan axis, which may be orthogonal to the scan axis of the fiber scanner.

[0127] The fiber scanner 1315 may include an optical fiber 1310 (or another suitable waveguide scanner) configured to scan a diverging input light beam 1311 toward an internally coupled DOE 1346 of the waveguide 1342 at a first angle of incidence θ. The optical fiber 1310 may be deflected such that the trajectory of its tip defines a one-dimensional convex object surface. As the light beam exits the tip of the optical fiber 1310, the light beam may diverge as a cone of rays (e.g., bounded by marginal rays 1350, as illustrated in FIG. 13 ) with a defined angle determined by the numerical aperture of the optical fiber 1310. An optical axis 1320 may be defined as a line that passes through the optical fiber 1310 when the optical fiber 1310 is not deflected.

[0128] A collimating scanning mirror 1330, disposed adjacent to the second surface 1322 of the waveguide 1342, receives the diverging input light beam 1311 from the fiber scanner 1315 through the waveguide 1342 and directs a collimated reflected light beam 1360 toward the waveguide-internal coupled DOE 1346 at a second angle of incidence θ r The method is configured to provide the

[0129] As shown in FIG. 13, an input light beam 1311 is incident on the eyepiece 1340 off-axis, e.g., at an angle θ, with respect to a normal 1302 of the waveguide 1342. The diffractive coupling of the incident light into the waveguide 1342 can be configured to achieve a desired diffractive coupling condition. For example, the incident angle θ and the grating period d of the in-coupling DOE 1346 may be selected to achieve a desired diffractive coupling condition. In some embodiments, the in-coupling DOE 1346 is configured to prevent a collimated input light beam from a collimated light source from propagating in the waveguide to the out-coupling DOE 1348 through total internal reflection (TIR) ​​and to propagate a reflected light beam 1360 collimated in the waveguide to the out-coupling DOE 1348 through total internal reflection (TIR). For ease of discussion, the direction oriented along the plane of the waveguide extending from the inner-coupled DOE 1346 towards the outer-coupled DOE 1348 is the "-X" direction, and the opposite direction is the "+X" direction.

[0130] For example, when an input light beam 1311 passes through the in-coupled DOE 1346, the negative first order diffraction by the in-coupled DOE 1346 at the diffraction angle on the first pass (in a reflection geometry) may lack the TIR condition of the waveguide 1342 towards the out-coupled DOE 1348 in the "-X" direction. In FIG. 13, lacking the TIR condition, the light beam propagates along the surface of the waveguide 1342 as an evanescent wave 1362 or is refracted out of the waveguide 1342 at each bounce within the waveguide 1342, as shown by the dotted line 1364. However, after the input light beam 1311 is reflected by the collimated scanning mirror 1330 and the scanned reflected light beam 1360 is incident on the in-coupling DOE 1346, the negative first order diffraction by the in-coupling DOE 1346 (in a transmission geometry) may satisfy the TIR condition of the waveguide 1342 towards the out-coupling DOE 1348 in the "-X" direction, as shown by light beam 1366. The out-coupling DOE 1348 may comprise a diffraction grating (which may be referred to herein as an out-coupling grating) configured to diffract a portion of the light propagating in the waveguide 1366 out of the waveguide 1342 towards the viewer's eye 1350. To illustrate the light path for image projection, the light beams diffracted in the waveguide and emitted to reach the viewer's eye 1370 are marked by grey arrows 1371, 1372, 1373, and 1374. To simplify the drawing, the light beam in the "+X" direction leaving the out-coupled DOE 1348 is omitted in Figure 13. Further details about the selective diffraction function of the in-coupled DOE are described above in connection with Figures 3, 4A, and 4B.

[0131] FIG. 13 illustrates an example of a waveguide display system with a fiber scanner providing a diverging light beam integrated with a collimated scanning mirror to provide a collimated light beam. This system allows the light source and the scanning mirror to be placed on opposite sides of the eyepiece waveguide. One advantage of this configuration is the reduced size of the device. Furthermore, this configuration can be implemented without polarization-sensitive DOEs, waveplates for modifying polarization, or polarization-dependent light sources, etc. The complexity and cost of the display system can be substantially reduced.

[0132] In some embodiments, the diverging light source and the collimating optical element can be placed on the same side of the waveguide and the scanning mirror on the other side of the waveguide. For example, the diverging input light beam may be provided by a fiber scanner that transmits the diverging input light beam through the in-coupling DOE to the scanning mirror. The scanning mirror can receive the diverging input light beam and transmit the diverging reflected light beam through the in-coupling DOE to the collimating optical element. The collimating optical element can reflect the collimated light beam towards the in-coupling DOE of the waveguide. In this case, the light beam passes through the in-coupling DOE three times. To reduce undesired diffraction, the in-coupling DOE can be configured to prevent the diverging input light beam from the fiber scanner and the reflected light beam from the scanning mirror from propagating to the out-coupling DOE in the waveguide through total internal reflection (TIR). The in-coupling DOE can also be configured to propagate a collimated light beam to the out-coupling DOE in a waveguide through total internal reflection (TIR). As with the embodiments described above, the angle of incidence of the light beam and / or the period (or pitch) of the in-coupling DOE can be selected to enable desired diffraction and suppress undesired diffraction. An example is illustrated in FIG.

[0133] FIG. 14 is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror, according to some embodiments of the present invention. As shown in FIG. 14, the waveguide display system 1400 includes an eyepiece waveguide 1440 having a planar waveguide 1442 with a first surface 1421 and a second surface 1422. The eyepiece waveguide 1440 also has an internally coupled diffractive optical element (DOE) 1446 coupled to a first lateral region of the waveguide 1442 and an externally coupled DOE 1448 coupled to a second lateral region of the waveguide 1442. A fiber scanner 1415 is disposed adjacent to the first surface 1421 of the waveguide 1442. A scanning optical element, e.g., a scanning mirror 1420, is disposed adjacent to the second surface of the waveguide. A collimating scanning optical element, such as a collimating scanning mirror 1430, is disposed adjacent to the first surface of the waveguide. The configuration of the fiber scanner, waveguide, scanning mirror, and collimating mirror in Figure 14 may be similar to the configuration of the corresponding components as shown in Figure 5. However, in the waveguide display system 1400, the fiber scanner 1415 is configured to be a line scanner, i.e., with one scanning axis, and the scanning mirror 1430 is a scanning mirror configured to scan with one scanning axis, which may be orthogonal to the scanning axis of the fiber scanner.

[0134] The fiber scanner 1415 may include an optical fiber 1410 (or another suitable waveguide scanner) configured to scan a diverging input light beam 1411 toward an internally coupled DOE 1446 of the waveguide 1442 at a first angle of incidence θ. The optical fiber 1410 is configured to be scanned linearly such that its tip moves along an arc in and out of the page (i.e., line scan), similar to the optical fiber 1310 illustrated in FIG. 13. The optical fiber 1410 may be deflected such that the trajectory of its tip defines a one-dimensional convex object surface. As the light beam exits the tip of the optical fiber 1410, it may diverge as a cone of rays (e.g., bounded by marginal rays 1450, as illustrated in FIG. 14) with a defined angle determined by the numerical aperture of the optical fiber 1410. Similar to the optical axis 1320 in FIG. 13, the optical axis may be defined in FIG. 14 as a line that passes through the optical fiber 1410 when the optical fiber 1410 is undeflected.

[0135] A scanning mirror 1420 is disposed adjacent to a second surface 1422 of the waveguide 1442. The scanning mirror 1420 can be configured to scan in a slow axis perpendicular to the plane of the page. The scanning mirror is configured to receive a diverging input light beam 1411 and provide a reflected light beam 1455 towards the waveguide at a second angle of incidence. The reflected light beam 1455 can span a range of angles of incidence with dotted lines marking marginal rays.

[0136] A collimating mirror 1430, positioned adjacent to the first surface 1421 of the waveguide 1442, is configured to receive the diverging reflected light beam 1455 from the scanning mirror 1420 through the internally coupled DOE 1446 of the waveguide 1442 and provide a collimated reflected light beam 1460 toward the internally coupled DOE 1446 of the waveguide at a third angle of incidence.

[0137] As shown in FIG. 14 , the diverging input light beam 1450, the scanned reflected diverging light beam 1455, and the collimated light beam 1460 are incident on the eyepiece 1440 off-axis, e.g., at an angle, with respect to the normal of the waveguide 1442. The diffractive coupling of the incident light beams into the waveguide 1442 can be configured to achieve a desired diffractive coupling condition. For example, the incident angle θ and the grating period d of the in-coupling DOE 1446 may be selected to achieve a desired diffractive coupling condition. In some embodiments, the in-coupling DOE 1446 is configured to prevent the diverging input light beam 1450 and the reflected diverging light beam 1455 from the collimated light source from propagating in the waveguide to the out-coupling DOE 1448 through total internal reflection (TIR), and to propagate the collimated light beam 1460 in the waveguide to the out-coupling DOE 1448 through total internal reflection (TIR). For ease of discussion, the direction oriented along the plane of the waveguide extending from the inner-coupled DOE 1446 towards the outer-coupled DOE 1448 is the "-X" direction, and the opposite direction is the "+X" direction.

[0138] For example, when a diverging input light beam 1450 passes through the in-coupling DOE 1446, the negative first order diffraction by the in-coupling DOE 1446 at the diffraction angle on the first pass (in transmission geometry) may lack the TIR condition of the waveguide 1442 towards the out-coupling DOE 1448 in the "-X" direction. In FIG. 14, the light beam lacking the TIR condition propagates along the surface of the waveguide 1442 as an evanescent wave 1462 or is refracted out of the waveguide 1442 at each bounce within the waveguide 1442, as shown by the dotted line 1464. Similarly, the reflected diverging light beam 1455 is also configured to lack the TIR condition of the waveguide 1442 towards the out-coupling DOE 1448 in the "-X" direction. However, after the input light beam 1411 is reflected by the collimating scanning mirror 1430 and the collimated reflected light beam 1460 (also marked by grey arrow 1461) is incident on the in-coupling DOE 1446, the negative first order diffraction by the in-coupling DOE 1446 (in a transmission geometry) may satisfy the TIR condition of the waveguide 1442 towards the out-coupling DOE 1448 in the "-X" direction, as shown by light beam 1466. The out-coupling DOE 1448 may comprise a diffraction grating (which may be referred to herein as an out-coupling grating) configured to diffract a portion of the light beam 1466 out of the waveguide 1442 towards the viewer's eye 1470. To illustrate the light paths for image projection, the light beams that are diffracted in the waveguide and emitted to reach the viewer's eye 1470 are marked by grey arrows 1471, 1472, 1473, and 1474. To simplify the drawing, the light beams that are diffracted in the "+X" direction away from the out-coupled DOE 1448 are omitted in Figure 14. Further details about the selective diffraction function of the in-coupled DOE are described above in connection with Figures 3, 4A, 4B, 5, 6A, and 6B.

[0139] As explained above, FIG. 14 illustrates an example of a waveguide display system with a fiber scanner providing a diverging light beam integrated with a scanning mirror to provide a two-dimensional scanning light beam. A collimating mirror is then used to produce a collimated light beam for incoupling into the waveguide to form an image. This system allows the light source and the scanning mirror to be placed on opposite sides of the eyepiece waveguide. The collimating mirror can be placed on the same side as the light source. One advantage of this configuration is the reduced size of the device. Furthermore, this configuration can be implemented without polarization-sensitive DOEs, waveplates for modifying polarization, or polarization-dependent light sources, etc. The complexity and cost of the display system can be substantially reduced.

[0140] 15A diagrammatically illustrates a perspective view of a fiber scanning projector, according to some embodiments. The fiber scanning projector includes an optical fiber 1510 configured to be scanned linearly along an arc 1512 in the plane of the page (i.e., line scan). Instead of a perfectly round mirror, the fiber scanning projector further includes a cross section of a collimating mirror 1530. The cross section of the collimating mirror 1530 may be configured to receive a diverging input light beam 1550 or 1552 emitted from the tip of the optical fiber 1510 and produce a collimated light beam 1560 or 1562.

[0141] FIG. 15B diagrammatically illustrates a side view of the fiber scanning projector illustrated in FIG. 15A. The optical fiber 1510 is configured to scan along an arc into and out of the page. As shown, the normal 1502 of the cross section of the collimating mirror 1530 may be slightly tilted at an angle β with respect to the optical axis 1552 of the optical fiber 1510 such that the reflected collimated light beam 1560 is directed upwards and avoids the optical fiber 1510 (instead of being directed back towards the optical fiber 1510). The tilt angle β may be relatively small such that only a small amount of off-axis aberrations may be introduced.

[0142] In some embodiments, the diverging light source and the collimating optical element can be placed on the same side of the waveguide, and the scanning mirror on the other side of the waveguide, similar to the system illustrated in FIG. 14. However, in alternative embodiments, the diverging input light beam can be provided by a fiber scanner that transmits the diverging input light beam directly to the collimating optical element, which can transmit a collimated light beam through the in-coupling DOE on the other side of the waveguide to the scanning mirror. In this case, the light beam passes through the in-coupling DOE twice. To reduce undesired diffraction, the in-coupling DOE can be configured to prevent the collimated light beam from the collimating mirror from propagating through total internal reflection (TIR) ​​to the out-coupling DOE in the waveguide. The in-coupling DOE can also be configured to propagate the collimated light beam provided by the scanning mirror to the out-coupling DOE in the waveguide through total internal reflection (TIR). As with the embodiments described above, the angle of incidence of the light beam and / or the period (or pitch) of the incoupling DOE can be selected to enable desired diffraction and suppress undesired diffraction. An example is illustrated in FIG. 15C.

[0143] FIG. 15C is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror, according to some embodiments of the present invention. As shown in FIG. 15C, the waveguide display system 1500 includes an eyepiece waveguide 1540 having a planar waveguide 1542 with a first surface 1521 and a second surface 1522. The eyepiece waveguide 1540 also has an internally coupled diffractive optical element (DOE) 1546 coupled to a first lateral region of the waveguide 1542 and an externally coupled DOE 1548 coupled to a second lateral region of the waveguide 1542. A fiber scanner 1515 is disposed adjacent to the first surface 1521 of the waveguide 1542. A collimating scanning optical element, e.g., a collimating scanning mirror 1530, is disposed adjacent to the first surface of the waveguide on the same side as the fiber scanner. A scanning optical element, such as a scanning mirror 1520, is disposed adjacent to the second surface of the waveguide. In the waveguide display system 1500, the fiber scanner 1515 is configured to be a line scanner, i.e., with one scan axis, and the scanning mirror 1520 is a scanning mirror configured to scan with one scan axis, which may be orthogonal to the scan axis of the fiber scanner.

[0144] The fiber scanner 1515 may include an optical fiber 1510 (or another suitable waveguide scanner). The tip 1510 of the optical fiber may have an angled facet 1514 such that the optical axis 1552 of the input light beam 1550 emitted from the tip of the optical fiber 1510 is refracted at an angle α relative to the extension 1517 of the optical fiber 1510. The collimating mirror 1530 may be a cross section or piece of a collimating mirror instead of a perfectly round mirror. The cross section of the collimating mirror 1530 may be configured to receive the diverging input light beam 1550 emitted from the tip of the optical fiber 1510. The optical fiber 1510 may scan along an arc in and out of the page. As shown, the normal 1502 of the cross section of the collimating mirror 1530 may be slightly tilted at an angle β with respect to the optical axis 1552 such that the reflected collimated light beam 1560 is directed upward and misses the optical fiber 1510 (instead of being directed back toward the optical fiber 1510). The optical axis 1552 of the diverging input light beam 1550 is incident on the collimating mirror 1530 at an incidence angle β. Because of the tilt angle α, the magnitude of the angle β required to make the collimated light beam 1560 miss the optical fiber 1510 may be smaller. Thus, off-axis aberrations may be reduced, as described above in connection with FIGS. 15A and 15B.

[0145] The scanning mirror 1520 is disposed adjacent to a second surface 1522 of the waveguide 1542, on the opposite side of the waveguide from the fiber scanner and collimating mirror. The scanning mirror 1520 can be configured to scan in a slow axis perpendicular to the plane of the page. The scanning mirror is configured to receive a collimated light beam 1560 through the in-coupled DOE and provide a scanned reflected light beam 1565 towards the waveguide at a second angle of incidence.

[0146] Similar to the embodiments described above, the diffractive coupling of the incident light beam into the waveguide can be configured to achieve a desired diffractive coupling condition. For example, the incident angle θ of the light beam and the grating period d of the inward coupling DOE 1546 may be selected to achieve a desired diffractive coupling condition. In some embodiments, the inward coupling DOE 1546 is configured to prevent the collimated light beam 1560 from propagating to the outward coupling DOE in the waveguide through total internal reflection (TIR). The inward coupling DOE 1546 is also configured to propagate the collimated scanned light beam from the scanning mirror to the outward coupling DOE in the waveguide through total internal reflection (TIR). To facilitate discussion, the direction oriented along the plane of the waveguide extending from the inward coupling DOE 1546 toward the outward coupling DOE 1548 is the "-X" direction, and the opposite direction is the "+X" direction.

[0147] For example, when a diverging light beam 1560 passes through the in-coupled DOE 1546, the negative first order diffraction by the in-coupled DOE 1546 at the diffraction angle on the first pass (in transmission geometry) may lack the TIR condition of the waveguide 1542 towards the out-coupled DOE 1548 in the "-X" direction. In FIG. 15, lacking the TIR condition, the light beam propagates along the surface of the waveguide 1542 as an evanescent wave 1562 or is refracted out of the waveguide 1542 at each bounce within the waveguide 1542, as shown by the dotted line 1564. However, when the collimated reflected light beam 1565 is incident on the in-coupling DOE 1546, the negative first order diffraction by the in-coupling DOE 1546 (in a transmission geometry) may satisfy the TIR condition of the waveguide 1542 towards the out-coupling DOE 1548 in the "-X" direction, as shown by the light beam 1566. The out-coupling DOE 1548 may comprise a diffraction grating (which may be referred to herein as an out-coupling grating) configured to diffract a portion of the light beam 1566 out of the waveguide 1542 towards the viewer's eye 1570. To illustrate the light path for image projection, the light beams diffracted within the waveguide and emitted to reach the viewer's eye 1570 are marked by grey arrows 1571, 1572, 1573, and 1574. To simplify the drawing, the light beams diffracted in the "+X" direction away from the out-coupling DOE 1548 are omitted in FIG. 15C. Further details regarding the selective diffraction function of the internally coupled DOE are described above in connection with Figures 3, 4A, 4B, 5, 6A, and 6B.

[0148] As described above, FIG. 15C illustrates an example of a waveguide display system with a fiber scanner providing a diverging light beam integrated with a scanning mirror to provide a two-dimensional scanning light beam. A collimating mirror is then used to produce a collimated light beam for incoupling into the waveguide to form an image. This system allows the light source and the collimating mirror to be placed on the same side of the eyepiece waveguide and the scanning mirror on the other side. Furthermore, the collimating mirror is in the shape of a cross section or a small piece to avoid the fiber scanner being in the optical path of the light beam reflected from the collimating mirror. One advantage of this configuration is the reduced size of the device. Furthermore, this configuration can be implemented without a polarization-sensitive DOE, a wave plate for modifying the polarization, or a polarization-dependent light source, etc. The complexity and cost of the display system can be substantially reduced.

[0149] FIG. 16 is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror according to some embodiments of the present invention. The waveguide display system may include an optical fiber 1610. The tip of the optical fiber 1610 may have an angled facet 1612 such that an input light beam 1650 is refracted at the facet 1612 and incidents upwards towards a MEMS mirror 1620. The MEMS scanning mirror 1620 may be configured to be scanned in a slow axis perpendicular to the plane of the page. Here, the MEMS mirror 1620 scans a diverging light beam 1650 instead of a collimated light beam. The fiber scanning projector may further include a collimating lens 1630 configured to receive the diverging light beam 1650′ reflected by the MEMS mirror 1620 and produce a collimated light beam 1670 for incidence on the eyepiece lens 1640. The eyepiece 1640 includes a waveguide 1642 and an in-coupled DOE 1646 coupled to a first lateral region of the waveguide 1642. A collimated light beam 1670 may be diffracted within the waveguide by the in-coupled DOE 1646, propagate by total internal reflection (TIR), and reach an out-coupled DOE (not shown).

[0150] The light source illustrated in the example of Figure 16 is an optical fiber. In other embodiments, the light source can be provided by a cantilever scanner with a waveguide, similar to the cantilever scanners described below in connection with Figures 18A-18D, 19-20, 21A-21C, and 22A-22B.

[0151] In some embodiments, it may be desirable to modify the system of FIG. 16 to position the collimating mirror on the other side of the waveguide, allowing for a more compact configuration. In some embodiments, the diverging light source and the collimating optical element can be placed on the same side of the waveguide and the scanning mirror on the other side of the waveguide. In an embodiment, the diverging input light beam may be provided by a fiber point source that transmits the diverging input light beam to the scanning mirror. The scanning mirror can receive the diverging input light beam and transmit the diverging scanned light beam through the in-coupling DOE to the collimating optical element. The collimating optical element can reflect the collimated light beam towards the in-coupling DOE of the waveguide. The configuration of the scanned diverging light beam from the scanning mirror and the collimated light beam from the collimating mirror is similar to that in the system of FIG. 14. However, in the system of FIG. 14, the diverging light beam from the fiber is transmitted through the in-coupling DOE of the waveguide before reaching the scanning mirror. Thus, the light beam passes through the in-coupling DOE three times. In alternative embodiments, the diverging light beam from the fiber is transmitted through the waveguide without passing through the in-coupling DOE. For example, the diverging light beam from the fiber is transmitted through a region of the waveguide outside the in-coupling DOE. In alternative embodiments, the fiber light source can be positioned on the same side of the scanning mirror such that the diverging light beam from the fiber can reach the scanning mirror without traveling through a waveguide. In these alternative embodiments, the light beam passes through the in-coupling DOE only two times. To reduce undesired diffraction, the in-coupling DOE can be configured to prevent the light beam reflected from the scanning mirror from propagating through total internal reflection (TIR) ​​to the out-coupling DOE in the waveguide. The in-coupling DOE can also be configured to propagate a collimated light beam from the collimating mirror to the out-coupling DOE in a waveguide through total internal reflection (TIR).As with the embodiments described above, the angle of incidence of the light beam and / or the period (or pitch) of the in-coupling DOE can be selected to enable desired diffraction and suppress undesired diffraction. Two examples are illustrated in Figures 17A and 17B.

[0152] 17A is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror, according to some embodiments of the present invention. As shown in FIG. 17A, the waveguide display system 1700 includes an eyepiece waveguide 1740 having a planar waveguide 1742 with a first surface 1721 and a second surface 1722. The eyepiece waveguide 1740 also has an internally coupled diffractive optical element (DOE) 1746 coupled to a first lateral region of the waveguide 1742 and an externally coupled DOE 1748 coupled to a second lateral region of the waveguide 1742. A fiber point source 1715 is disposed adjacent to the first surface 1721 of the waveguide 1742. A scanning optical element, e.g., a scanning mirror 1720, is disposed adjacent to the second surface of the waveguide. A collimating scanning optical element, such as a collimating scanning mirror 1730, is disposed adjacent to the first surface of the waveguide. The configuration of the fiber light source, waveguide, scanning mirror, and collimating mirror in Figure 17A may be similar to the configuration of the corresponding components as shown in Figure 14.

[0153] However, in waveguide display system 1400, fiber scanner 1415 is configured to be a line scanner, i.e., with one scanning axis, and scanning mirror 1430 is a scanning mirror configured to scan with one scanning axis that may be orthogonal to the scanning axis of the fiber scanner.

[0154] Optical fiber tip 1710 has an angled facet 1712 such that an input light beam 1750 emitted from optical fiber tip 1710 is refracted at facet 1712 and incident on MEMS scanning mirror 1720 at an angle θ.

[0155] The fiber point source 1715 may include an optical fiber 1710 (or another suitable waveguide scanner). In some embodiments, the tip 1710 of the optical fiber has an angled facet 1712, which may be metallized, such that an input light beam 1750 emitted from the tip of the optical fiber 1710 is refracted at the facet 1712 and incident on the MEMS scanning mirror 1720 at an angle θ. As the diverging light beam exits the tip of the optical fiber 1710, the light beam may diverge as a cone of rays (e.g., bounded by marginal rays 1750, as illustrated in FIG. 17A ).

[0156] The scanning mirror 1720 is disposed adjacent to a second surface 1722 of the waveguide 1742. The scanning mirror is configured to receive a diverging input light beam 1750 from the fiber point source and provide a reflected light beam 1755 towards the waveguide at a second angle of incidence.

[0157] A collimating mirror 1730, positioned adjacent to the first surface 1721 of the waveguide 1742, is configured to receive the diverging reflected light beam 1755 from the scanning mirror 1720 through the internally coupled DOE 1746 of the waveguide 1742 and provide a collimated reflected light beam 1760 toward the internally coupled DOE 1746 of the waveguide at a third angle of incidence.

[0158] As shown in FIG. 17A, the diverging input light beam 1750, the scanned reflected diverging light beam 1755, and the collimated light beam 1760 are incident on the eyepiece 1740 off-axis, e.g., at an angle, with respect to the normal of the waveguide 1742. In the embodiment of FIG. 17A, the fiber point source 1715 is configured to provide the diverging input light beam to a portion of the waveguide outside the in-coupling DOE at a first incidence angle θ. The diffractive coupling of the incident light beam into the waveguide 1742 can be configured to achieve a desired diffractive coupling condition. For example, the incidence angle θ and the grating period d of the in-coupling DOE 1746 may be selected to achieve a desired diffractive coupling condition for the scanned reflected diverging light beam 1755 and the collimated light beam 1760. In some embodiments, the inward coupling DOE 1746 is configured to prevent a reflected diverging light beam 1755 from a collimated light source from propagating within the waveguide to the outward coupling DOE 1748 through total internal reflection (TIR) ​​and to allow a collimated light beam 1760 to propagate within the waveguide to the outward coupling DOE 1748 through total internal reflection (TIR). Similar to the description in connection with FIG. 14 , the direction oriented along the plane of the waveguide extending from the inward coupling DOE 1746 towards the outward coupling DOE 1748 is the “−X” direction and the opposite direction is the “+X” direction.

[0159] For example, when the reflected diverging light beam 1755 passes through the in-coupled DOE 1746, the negative first order diffraction by the in-coupled DOE 1746 at the diffraction angle on the first pass (in transmission geometry) may lack the TIR condition of the waveguide 1742 towards the out-coupled DOE 1748 in the "-X" direction. In Figure 17A, lacking the TIR condition, the light beam propagates along the surface of the waveguide 1742 as an evanescent wave 1762 or is refracted out of the waveguide 1742 at each bounce within the waveguide 1742, as shown by the dotted line 1764. However, when the collimated reflected light beam 1760 is incident on the in-coupling DOE 1746, the negative first order diffraction by the in-coupling DOE 1746 (in a transmission geometry) may satisfy the TIR condition of the waveguide 1742 towards the out-coupling DOE 1748 in the "-X" direction, as shown by light beam 1766. The out-coupling DOE 1748 may comprise a diffraction grating (which may be referred to herein as an out-coupling grating) configured to diffract a portion of the light beam 1766 out of the waveguide 1742 towards the viewer's eye 1770. To illustrate the light path for image projection, the light beams that are diffracted in the waveguide and emitted to reach the viewer's eye 1770 are marked by grey arrows 1771, 1772, 1773, and 1774. To simplify the drawing, the light beam that is diffracted in the "+X" direction away from the out-coupling DOE 1748 is omitted in Figure 17A. Further details about the selective diffraction function of the in-coupling DOE are described above in connection with Figures 3, 4A, 4B, 5, 6A, 6B, and 14.

[0160] As described above, FIG. 17A illustrates an example of a waveguide display system with a fiber point source providing a diverging light beam integrated with a scanning mirror to provide a two-dimensional scanning light beam. A collimating mirror is then used to produce a collimated light beam to be incoupled into a waveguide to form an image. The light source illustrated in the example of FIG. 17A is a fiber point source. In other embodiments, the light source can be provided by a cantilevered scanner with a waveguide, similar to the cantilevered scanner described below in connection with FIGS. 18A-18D, 19-20, 21A-21C, and 22A-22B. This system allows the light source and the scanning mirror to be placed on opposite sides of the eyepiece waveguide, and the collimating mirror can be placed on the same side as the light source. One advantage of this configuration is the reduced size of the device. Furthermore, this configuration can be implemented without a polarization-sensitive DOE, a waveplate for modifying the polarization, or a polarization-dependent light source, etc. The complexity and cost of the display system can be substantially reduced.

[0161] FIG. 17B is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror, according to some embodiments of the present invention. As shown in FIG. 17B, the waveguide display system 1701 includes an eyepiece waveguide 1740 having a planar waveguide 1742 with a first surface 1721 and a second surface 1722. The eyepiece waveguide 1740 also has an internally coupled diffractive optical element (DOE) 1746 coupled to a first lateral region of the waveguide 1742 and an externally coupled DOE 1748 coupled to a second lateral region of the waveguide 1742. A fiber point source 1715 is disposed adjacent to the first surface 1721 of the waveguide 1742. A scanning optical element, e.g., a scanning mirror 1720, is disposed adjacent to the second surface of the waveguide. A collimating scanning optical element, for example a collimating scanning mirror 1730, is disposed adjacent to the first surface of the waveguide.

[0162] FIG. 17B illustrates a waveguide display system 1701, which is similar to the waveguide display system 1700 of FIG. 17A. One difference is that in FIG. 17B, the fiber point source 1715 is located on the same side as the scanning mirror 1720. Thus, the diverging input light beam 1750 from the fiber point source 1715 to the scanning mirror 1720 does not pass through the waveguide 1742. The operation of the waveguide display system 1701 in FIG. 17B is otherwise similar to that of the waveguide display system 1700 in FIG. 17A. Thus, the detailed description will not be repeated here. To illustrate the light path for image projection, the light beams that are diffracted in the waveguide and emitted to reach the viewer's eye 1770 are marked by gray arrows 1771, 1772, 1773, and 1774. To simplify the drawing, the light beam that is diffracted in the "+X" direction away from the out-coupling DOE 1748 is omitted in FIG. 17B.

[0163] As described above, FIG. 17B illustrates an example of a waveguide display system with a fiber point source providing a diverging light beam integrated with a scanning mirror to provide a two-dimensional scanning light beam. A collimating mirror is then used to produce a collimated light beam for incoupling into the waveguide to form an image. The light source illustrated in the example of FIG. 17B is a fiber point source. In an alternative embodiment, the point source can be provided by a cantilevered point source, such as a cantilevered scanner with a waveguide, similar to the cantilevered scanner described below in connection with FIGS. 18A-18D, 19-20, 21A-21C, and 22A-22B. This system allows the light source and the scanning mirror to be located on the same side of the eyepiece waveguide, and the collimating mirror can be located on the opposite side of the waveguide. One advantage of this configuration is the reduced size of the device. Furthermore, the configuration can be implemented without polarization-sensitive DOEs, waveplates for modifying polarization, or polarization-dependent light sources, etc. The complexity and cost of the display system can be substantially reduced.

[0164] In various embodiments of the waveguide display system described above, a light source is used that includes a fiber scanner. In alternative embodiments, a light source incorporating a MEMS cantilever scanner can be used. Some examples are described below.

[0165] 18A-18C are simplified perspective views illustrating various examples of a cantilever-shaped MEMS scanner, according to some embodiments of the present invention. As illustrated in FIGS. 18A-18C, discrete piezoelectric film actuators are used to induce movement of the cantilever beam in the MEMS scanner 1800. In some embodiments, the MEMS scanner 1800 can be formed using a silicon-on-insulator (SOI) wafer structure, including a base region 1802 and a cantilever beam 1804. FIG. 18A illustrates how the base region 1802 and a portion of the cantilever beam 1804 can be formed from a layer of material, such as a single crystal silicon layer 1806. In some embodiments, the single crystal silicon layer 1806, which forms the base region 1802 and a portion of the cantilever beam 1804, can be about 100 μm thick, thereby enabling deflection of the cantilever beam 1804 during operation of the MEMS scanner 1800. A waveguide 1808 can be formed along the base region 1802 and the upper surface of the cantilever beam 1804. In some embodiments, light can be received by the waveguide 1808 from laser diodes 1809-1, 1809-2, and 1809-3, which are affixed to the surface of the single crystal silicon layer 1806. In some embodiments, the laser diode 1809-1 can be a red laser diode, the laser diode 1809-2 can be a blue laser diode, and the laser diode 1809-3 can be a green laser diode. In some embodiments, additional laser diodes can be added to allow a greater variety of colors to be produced by mixing light generated by two or more of the laser diodes 1809 and propagated through the waveguide 1808. The base region 1802 can be affixed to a support structure to secure the MEMS scanner 1800 in place and to accommodate additional optics for propagating light emitted from the distal end of the cantilever and the distal end of the waveguide 1808.

[0166] Base region 1802 may also include a layer of silicon 1812 bonded to single crystal silicon layer 1806. In some embodiments, single crystal silicon layer 1806 may be bonded to silicon layer 1812 by a compressive bonding operation resulting in the two layers being bonded by a silicon oxide layer. Silicon layer 1812 may be configured to provide structural support to base region 1802 and may be approximately 200 μm thick, i.e. twice as thick as single crystal silicon layer 1806, which may have a thickness of approximately 100 μm. In some embodiments, silicon layer 1812 may provide a mounting surface to which one or more actuation structures may be affixed.

[0167] FIG. 18A also depicts a scanning mechanism including four piezoelectric film actuators 1814 configured to cooperatively steer the cantilever beam 1804 in a desired scanning pattern. Each of the actuators 1814-1 and 1814-4 can be actuated in the same or different directions to impart different forces on the cantilever beam 1804. Because the piezoelectric film actuators 1814-1 and 1814-2 are substantially coplanar, an input that causes both the piezoelectric actuators 1814-1 and 1814-2 to expand longitudinally will induce a downward movement of the cantilever beam 1804 in the −y direction, while an input that causes the piezoelectric film actuators 1814-1 and 1814-2 to contract longitudinally will induce an upward movement of the cantilever beam 1804 in the +y direction. Simultaneous actuation of all four of the piezoelectric film actuators 1814 can increase the amount of force imparted on the cantilever beam 1804. For example, sending a contraction signal to piezoelectric film actuators 1814-1 and 1814-2 and an expansion signal to piezoelectric film actuators 1814-3 and 1814-4 will induce upward movement of cantilever beam 1804 in the +y direction. Sending an expansion signal to piezoelectric film actuators 1814-1 and 1814-3 and a contraction signal to piezoelectric film actuators 1814-2 and 1814-4 will induce lateral movement of cantilever beam 1804 in the +X direction, while reversing the signals will induce lateral movement of cantilever beam 1804 in the -x direction.

[0168] 18B shows an alternative configuration for the MEMS scanner 1803 in which the piezoelectric film actuators 1814-5, 1814-6, 1814-7, and 1814-8 are arranged on the lateral surfaces of the cantilever beam 1804. This configuration has the advantage of placing the piezoelectric film actuators 1814-5-1814-8 on a different surface than the waveguide 1808, thereby allowing the piezoelectric actuators 1814 to occupy a larger area of ​​the cantilever beam 1804. The contraction and expansion inputs can be adjusted to achieve movement of the cantilever beam 1804 in the +x, -x, +y, and -y directions. For example, by sending a contraction signal to the piezoelectric actuators 1814-5 and 1814-6 and an expansion signal to the piezoelectric film actuators 1814-7 and 1814-8, movement of the cantilever beam in the +y direction can be achieved. A circular scan pattern of the cantilever beam 1804 can be established by applying a differential signal to the piezoelectric actuator 1814. Vertical and horizontal patterns are also possible if a line scan pattern is desired.

[0169] 18C shows another alternative configuration of the MEMS scanner 1805 in which piezoelectric film actuators 1814-1 and 1814-2 are positioned on the upwardly facing surface of the cantilever 1804. The piezoelectric film actuators 1814-1 and 1814-2 can steer the cantilever 1804 in the +x, -x, -y, and +y directions, such that the cantilever 1804 can be driven in a single axis or circular scan pattern, as discussed above. For example, providing a contraction signal / input to the piezoelectric film actuator 1814-1 and an expansion signal / input to the piezoelectric film actuator 1814-2 will move the cantilever 1804 laterally in the +X direction.

[0170] The piezoelectric actuator 1814 can be controlled according to the control methods described below in conjunction with Figure 18D. In some embodiments, a strain gauge positioned on or adjacent to the cantilever beam 1804 can be configured to track the movement of the cantilever beam 1804 and can provide feedback for the control methods described above.

[0171] FIG. 18D is an electrical schematic diagram illustrating a four-phase signal splitter network 1850 for driving a piezoelectric actuator 1826, according to an embodiment of the present invention. For purposes of clarity, the piezoelectric actuator is illustrated separately from the rest of the piezoelectric scanner. In some embodiments, the four phases are applied to the piezoelectric actuators 1826, which are arranged on opposite sides of the scanning assembly. A signal generator 1812 provides an output that is connected to the conductive paths and, in turn, to a corresponding actuation input. The signal generator 1812 is also connected to a first 90° phase shifter 1824 and a second 90° phase shifter 1826, which are connected to the piezoelectric actuators 1816-1 and 1816-4. Thus, the signal generator 1812 in conjunction with the phase shifters 1824 and 1826 provides four phases that are 90° out of phase with respect to each other.

[0172] For purposes of the discussion of FIG. 18D, the piezoelectric actuators 1826 may all be considered to be polarized in the same vertical direction. The four piezoelectric actuators 1826 may be considered to be grouped in two pairs. The first pair may be considered to include a first piezoelectric actuator 1816-1 and a third piezoelectric actuator 1816-3, while the second pair may be considered to include a second piezoelectric actuator 1816-2 and a fourth piezoelectric actuator 1816-4. The four-phase splitter network 1850 is configured such that within each of the actuators of said pairs, the electric field directions established by the network 1850 within the piezoelectric actuators associated with each pair are directed in opposite directions. Thus, when one member of each pair is induced to contract by an applied electric field acting through the medium of the piezoelectric effect, the other member of the pair will be induced to expand. The two pairs, a first pair of piezoelectric actuators 1816-1 and 1816-3 and a second pair of piezoelectric actuators 1816-2 and 1816-4, can be said to drive two perpendicular axes (the X'-axis and Y'-axis shown) of the scanner. For purposes of discussion, imagine the X'-axis rotated about the stationary axis of the scanner out of plane.

[0173] 18D, a single signal generator 1812 provides signals to all four piezoelectric actuators 1826, although, as discussed below, circuitry may alternatively be provided to provide separate phase and amplitude control signals to a first (X'-axis) pair of piezoelectric actuators 1816-1 and 1816-3 and a second (Y'-axis) pair of piezoelectric actuators 1816-2 and 1816-4. Additionally, the network 1850 and signal generator 1812 can be employed to drive a scanner with only two piezoelectric actuators 1826. Further details of cantilevered scanners and piezoelectric actuators are described in PCT Application No. PCT / US2019 / 039088, filed June 25, 2019, the contents of which are incorporated herein by reference in their entirety.

[0174] In some embodiments, the diverging light source and the collimating optical element can be placed on opposite sides of the waveguide. For example, the incident light beam can be a diverging light beam provided by a cantilever scanner such as that described above in connection with Figs. 18A-18D, and the collimating scanning mirror can be a scanning mirror, e.g., a scanning concave mirror, having a reflective optical element with positive refractive power. The incidence angle of the light beam and / or the period (or pitch) of the in-coupling DOE can be selected to prevent the incident light beam from propagating to the output grating in the waveguide through total internal reflection (TIR). The incidence angle of the light beam and / or the period or pitch of the grating can also be configured to propagate the collimated scanned reflected light beam in the waveguide through total internal reflection (TIR) ​​to the out-coupling DOE to form an image that can be viewed by a user. An example is illustrated in Fig. 19.

[0175] 19 is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror, according to some embodiments of the present invention. As shown in FIG. 19, the waveguide display system 1900 is similar to the waveguide display system 1300 illustrated in FIG. 13. The difference between these waveguide display systems is that the waveguide display system 1300 illustrated in FIG. 13 has a fiber scanner 1315, while the waveguide display system 1900 illustrated in FIG. 19 has a cantilever scanner 1915. Thus, similar components within the waveguide display systems are designated with the same reference numbers, and the discussion provided in connection with FIG. 13 is applicable to FIG. 19, where appropriate.

[0176] As shown in FIG. 19, the waveguide display system 1900 includes an eyepiece waveguide 1340 having a planar waveguide 1342 with a first surface 1321 and a second surface 1322. The eyepiece waveguide 1340 also has an internally coupled diffractive optical element (DOE) 1346 coupled to or integrally formed with a first lateral region of the waveguide 1342, and an externally coupled DOE 1348 coupled to or integrally formed with a second lateral region of the waveguide 1342. A cantilevered scanner 1915 is disposed adjacent to the first surface 1321 of the waveguide 1342. A collimating scanning optical element, for example, a collimating scanning mirror 1330, is disposed adjacent to the second surface of the waveguide. The configuration of the fiber scanner, waveguide, and collimating mirror in FIG. 13 may be similar to the configuration of the corresponding components as shown in FIG. 3. However, in the waveguide display system 1900, the cantilevered scanner 1915 is configured to be a line scanner, i.e., with one scanning axis, and the collimating mirror 1330 is a scanning mirror configured to scan with one scanning axis that may be orthogonal to the scanning axis of the fiber scanner.

[0177] The cantilevered scanner 1915 may include a cantilevered optical member 1910, which may include a cantilever and a waveguide, coupled to a light source similar to that described above in connection with FIGS. 18A-18C. The cantilevered scanner 1915 is configured to scan the diverging input light beam 1311 toward the in-coupled DOE 1346 of the waveguide 1342 at a first angle of incidence θ. The cantilevered optical member 1910 may be deflected such that the trajectory of its tip defines a one-dimensional convex object surface. As the light beam exits the tip of the cantilevered optical member 1910, the light beam may diverge as a cone of rays (e.g., bounded by marginal rays 1350, as illustrated in FIG. 19) with a defined angle determined by the numerical aperture of the cantilevered optical member 1910. The optical axis 1320 may be defined as a line that passes through the cantilevered optical element 1910 when the cantilevered optical element 1910 is undeflected.

[0178] A collimating scanning mirror 1330, disposed adjacent to the second surface 1322 of the waveguide 1342, receives the diverging input light beam 1311 from the cantilever scanner 1915 through the waveguide 1342 and directs a collimated reflected light beam 1360 toward the waveguide-internal coupled DOE 1346 at a second angle of incidence θ r The method is configured to provide the

[0179] As shown in FIG. 19 , the input light beam 1311 is incident on the eyepiece 1340 off-axis, e.g., at an angle θ, with respect to the normal 1302 of the waveguide 1342. The diffractive coupling of the incident light into the waveguide 1342 can be configured to achieve a desired diffractive coupling condition. For example, the incident angle θ and the grating period d of the in-coupling DOE 1346 may be selected to achieve a desired diffractive coupling condition, as described above in connection with FIG. 3 . In some embodiments, the in-coupling DOE 1346 is configured to prevent the collimated reflected light beam 1360 from the collimating scanning mirror 1330 from propagating in the waveguide to the out-coupling DOE 1348 through total internal reflection (TIR), and to propagate the collimated reflected light beam 1360 in the waveguide to the out-coupling DOE 1348 through total internal reflection (TIR). For ease of discussion, the direction oriented along the plane of the waveguide extending from the inner-coupled DOE 1346 towards the outer-coupled DOE 1348 is the "-X" direction, and the opposite direction is the "+X" direction.

[0180] For example, when the input light beam 1311 passes through the in-coupled DOE 1346, the negative first order diffraction by the in-coupled DOE 1346 at the diffraction angle on the first pass (in a reflection geometry) may lack the TIR condition of the waveguide 1342 towards the out-coupled DOE 1348 in the "-X" direction. In FIG. 19, lacking the TIR condition, the light beam may propagate along the surface of the waveguide 1342 as an evanescent wave 1362 or may be refracted out of the waveguide 1342 at each bounce within the waveguide 1342, as shown by the dotted line 1364. However, after the input light beam 1311 is reflected by the collimated scanning mirror 1330 and the scanned reflected light beam 1360 is incident on the in-coupling DOE 1346, the negative first order diffraction by the in-coupling DOE 1346 (in a transmission geometry) may satisfy the TIR condition of the waveguide 1342 towards the out-coupling DOE 1348 in the "-X" direction, as shown by light beam 1366. The out-coupling DOE 1348 may comprise a diffraction grating (which may be referred to herein as an out-coupling grating) configured to diffract a portion of the light propagating in the waveguide 1366 out of the waveguide 1342 towards the viewer's eye 1350. To illustrate the light path for image projection, the light beams diffracted in the waveguide and emitted to reach the viewer's eye 1370 are marked by grey arrows 1371, 1372, 1373, and 1374. To simplify the drawing, the light beam in the "+X" direction leaving the out-coupling DOE 1348 is omitted in Figure 19. Further details about the selective diffraction function of the in-coupling DOE are described above in connection with Figures 3, 4A, and 4B.

[0181] FIG. 19 illustrates an example of a waveguide display system with a cantilevered scanner providing a diverging light beam integrated with a collimated scanning mirror to provide a collimated light beam. This system allows the light source and the scanning mirror to be placed on opposite sides of the eyepiece waveguide. One advantage of this configuration is the reduced size of the device. Furthermore, this configuration can be implemented without polarization-sensitive DOEs, waveplates for modifying polarization, or polarization-dependent light sources, etc. The complexity and cost of the display system can be substantially reduced.

[0182] In some embodiments, the diverging light source and the collimating optical element can be placed on the same side of the waveguide and the scanning mirror on the other side of the waveguide. For example, the diverging input light beam can be provided by a cantilevered scanner that transmits the diverging input light beam through the in-coupling DOE to the scanning mirror. The scanning mirror can receive the diverging input light beam and transmit the diverging reflected light beam through the in-coupling DOE to the collimating optical element. The collimating optical element can reflect the collimated light beam towards the in-coupling DOE of the waveguide. In this case, the light beam passes through the in-coupling DOE three times. To reduce undesired diffraction, the in-coupling DOE can be configured to prevent the diverging input light beam from the fiber scanner and the reflected light beam from the scanning mirror from propagating to the out-coupling DOE in the waveguide through total internal reflection (TIR). The in-coupling DOE can also be configured to propagate the collimated light beam to the out-coupling DOE in the waveguide through total internal reflection (TIR). As with the embodiments described above, the angle of incidence of the light beam and / or the period (or pitch) of the in-coupling DOE can be selected to enable desired diffraction and suppress undesired diffraction. An example is illustrated in FIG. 20. Thus, in some embodiments, a cantilevered mirror that scans in one dimension is used to generate a line, and a second scanning mirror (e.g., a MEMS mirror that scans in one dimension in an orthogonal direction) is used to convert the line to a plane. In some implementations, the order of the mirrors can be switched such that a collimating mirror is utilized before the second scanning mirror (e.g., a MEMS mirror), although this is not required by the present invention.

[0183] 20 is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror, according to some embodiments of the present invention. As shown in FIG. 20, the waveguide display system 2000 is similar to the waveguide display system 1400 illustrated in FIG. 14. The difference is that the waveguide display system 1400 illustrated in FIG. 14 has a fiber scanner 1415, while the waveguide display system 2000 illustrated in FIG. 20 has a cantilever scanner 2015. Thus, similar components within the waveguide display system are designated with the same reference numbers, and the discussion provided in connection with FIG. 14 is applicable to FIG. 20, where appropriate.

[0184] As shown in FIG. 20, the waveguide display system 2000 includes an eyepiece waveguide 1440 having a planar waveguide 1442 with a first surface 1421 and a second surface 1422. The eyepiece waveguide 1440 also has an internally coupled diffractive optical element (DOE) 1446 coupled to a first lateral region of the waveguide 1442 and an externally coupled DOE 1448 coupled to a second lateral region of the waveguide 1442. A cantilevered scanner 2015 is disposed adjacent to the first surface 1421 of the waveguide 1442. A scanning optical element, e.g., a scanning mirror 1420, is disposed adjacent to the second surface of the waveguide. A collimating scanning optical element, e.g., a collimating scanning mirror 1430, is disposed adjacent to the first surface of the waveguide. The configuration of the cantilever scanner, waveguide, scanning mirror, and collimating mirror in Figure 20 may be similar to the configuration of the corresponding components as shown in Figure 19. In the waveguide display system 2000, the cantilever scanner 2015 is configured to be a line scanner, i.e., with one scan axis, and the scanning mirror 1430 is a scanning mirror configured to scan with one scan axis, which may be orthogonal to the scan axis of the fiber scanner.

[0185] The cantilevered scanner 2015 may include a cantilevered optical member 2010, which may include a cantilever and a waveguide, coupled to a light source similar to that described above in connection with Figures 18A-18C. The cantilevered scanner 2015 is configured to scan the diverging input light beam 1411 toward the in-coupled DOE 1446 of the waveguide 1442 at a first angle of incidence θ. The cantilevered optical member 2010 is configured to be scanned linearly such that its tip moves along an arc in and out of the page (i.e., line scan), similar to the cantilevered optical member 1910 illustrated in Figure 19. The cantilevered optical member 2010 may be deflected such that the trajectory of its tip defines a one-dimensional convex object surface. As the light beam exits the tip of the cantilevered optical element 2010, it may diverge as a cone of rays (e.g., bounded by marginal rays 1450, as illustrated in FIG. 20) with a defined angle determined by the numerical aperture of the cantilevered optical element 2010. Similar to the optical axis 1320 in FIG. 19, the optical axis may be defined in FIG. 20 as a line that passes through the cantilevered optical element 2010 when it is undeflected.

[0186] A scanning mirror 1420 is disposed adjacent to a second surface 1422 of the waveguide 1442. The scanning mirror 1420 can be configured to scan in a slow axis perpendicular to the plane of the page. The scanning mirror is configured to receive a diverging input light beam 1411 and provide a reflected light beam 1455 towards the waveguide at a second angle of incidence. The reflected light beam 1455 can span a range of angles of incidence with dotted lines marking marginal rays.

[0187] A collimating mirror 1430, positioned adjacent to the first surface 1421 of the waveguide 1442, is configured to receive the diverging reflected light beam 1455 from the scanning mirror 1420 through the internally coupled DOE 1446 of the waveguide 1442 and provide a collimated reflected light beam 1460 toward the internally coupled DOE 1446 of the waveguide at a third angle of incidence.

[0188] 20, the diverging input light beam 1450, the scanned reflected diverging light beam 1455, and the collimated light beam 1460 are incident on the eyepiece 1440 off-axis, e.g., at an angle, with respect to the normal to the waveguide 1442. The diffractive coupling of the incident light beams into the waveguide 1442 can be configured to achieve a desired diffractive coupling condition. For example, the incidence angle θ and the grating period d of the in-coupling DOE 1446 may be selected to achieve a desired diffractive coupling condition, as described above in connection with FIG. In some embodiments, the inward coupling DOE 1446 is configured to prevent the diverging input light beam 1450 and the reflected diverging light beam 1455 from the collimated light source from propagating within the waveguide to the outward coupling DOE 1448 through total internal reflection (TIR), and to allow the collimated light beam 1460 to propagate within the waveguide to the outward coupling DOE 1448 through total internal reflection (TIR). For ease of discussion, the direction oriented along the plane of the waveguide extending from the inward coupling DOE 1446 towards the outward coupling DOE 1448 is the "-X" direction, and the opposite direction is the "+X" direction.

[0189] For example, when a diverging input light beam 1450 passes through the in-coupling DOE 1446, the negative first order diffraction by the in-coupling DOE 1446 at the diffraction angle on the first pass (in transmission geometry) may miss the TIR condition of the waveguide 1442 towards the out-coupling DOE 1448 in the "-X" direction. In FIG. 20, the light beam, which misses the TIR condition, may propagate along the surface of the waveguide 1442 as an evanescent wave 1462 or may be refracted out of the waveguide 1442 at each bounce within the waveguide 1442, as shown by the dotted line 1464. Similarly, the reflected diverging light beam 1455 is also configured to miss the TIR condition of the waveguide 1442 towards the out-coupling DOE 1448 in the "-X" direction. However, after the input light beam 1411 is reflected by the collimating mirror 1430 and the collimated reflected light beam 1460 (also marked by grey arrow 1471) is incident on the in-coupling DOE 1446, the negative first order diffraction by the in-coupling DOE 1446 (in a transmission geometry) may satisfy the TIR condition of the waveguide 1442 towards the out-coupling DOE 1448 in the "-X" direction, as shown by light beam 1466. The out-coupling DOE 1448 may comprise a diffraction grating (which may be referred to herein as an out-coupling grating) configured to diffract a portion of the light beam 1466 out of the waveguide 1442 towards the viewer's eye 1470. To illustrate the light path for image projection, the light beams diffracted in the waveguide and emitted to reach the viewer's eye 1470 are marked by grey arrows 1471, 1472, 1473, and 1474. To simplify the drawing, the light beam that is diffracted in the "+X" direction away from the out-coupling DOE 1448 is omitted in Figure 20. Further details about the selective diffraction function of the in-coupling DOE are described above in connection with Figures 3, 4A, 4B, 5, 6A, and 6B.

[0190] As described above, FIG. 20 illustrates an example of a waveguide display system with a cantilevered scanner providing a diverging light beam integrated with a scanning mirror to provide a two-dimensional scanning light beam. A collimating mirror is then used to produce a collimated light beam for incoupling into the waveguide to form an image. This system allows the light source and the scanning mirror to be placed on opposite sides of the eyepiece waveguide. The collimating mirror can be placed on the same side as the light source. One advantage of this configuration is the reduced size of the device. Furthermore, this configuration can be implemented without a polarization-sensitive DOE, a waveplate for modifying the polarization, or a polarization-dependent light source, etc. The complexity and cost of the display system can be substantially reduced.

[0191] 21A is a perspective view illustrating a cantilever scanning projector according to some embodiments of the present invention. The cantilever scanning projector includes a cantilever scanner 2115 with a cantilevered optical element 2110 configured to be scanned linearly along an arc 2112 in the plane of the page (i.e., line scan). Instead of a perfectly round mirror, the cantilever scanning projector further includes a cross section of a collimating mirror 2130. The cross section of the collimating mirror 2130 may be configured to receive a diverging input light beam 2150 or 2152 emitted from the tip of the cantilevered optical element 2110 and produce a collimated light beam 2160 or 2162.

[0192] FIG. 21B diagrammatically illustrates a side view of the cantilevered scanning projector illustrated in FIG. 21A. The cantilevered optical element 2110 is configured to scan along an arc in and out of the plane of the figure (i.e., in and out of the page). As shown, the normal 2102 of the cross section of the collimating mirror 2130 may be slightly tilted at an angle β with respect to the optical axis 2152 of the cantilevered optical element 2110 such that the reflected collimated light beam 2160 is directed upwards and avoids the cantilevered optical element 2110 (instead of being directed back towards the cantilevered optical element 2110). The tilt angle β may be relatively small such that only a small amount of off-axis aberrations may be introduced.

[0193] In some embodiments, the diverging light source and the collimating optical element can be placed on the same side of the waveguide, and the scanning mirror on the other side of the waveguide, similar to the system illustrated in FIG. 20. However, in alternative embodiments, the diverging input light beam may be provided by a cantilevered scanner that transmits the diverging input light beam directly to the collimating optical element, which can transmit a collimated light beam through the in-coupling DOE on the other side of the waveguide to the scanning mirror. In this case, the light beam passes through the in-coupling DOE twice. To reduce undesired diffraction, the in-coupling DOE can be configured to prevent the collimated light beam from the collimating mirror from propagating through total internal reflection (TIR) ​​to the out-coupling DOE in the waveguide. The in-coupling DOE can also be configured to propagate the collimated light beam provided by the scanning mirror to the out-coupling DOE in the waveguide through total internal reflection (TIR). As with the embodiments described above, the angle of incidence of the light beam and / or the period (or pitch) of the incoupling DOE can be selected to enable desired diffraction and suppress undesired diffraction. An example is illustrated in FIG. 21C.

[0194] 21C is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror, according to some embodiments of the present invention. As shown in FIG. 21C, the waveguide display system 2100 includes an eyepiece waveguide 2140 having a planar waveguide 2142 with a first surface 2121 and a second surface 2122. The eyepiece waveguide 2140 also has an internally coupled diffractive optical element (DOE) 2146 coupled to or otherwise formed with a first lateral region of the waveguide 2142, and an externally coupled DOE 2148 coupled to or otherwise formed with a second lateral region of the waveguide 2142. Although the DOE 2146 and the DOE 2148 are shown on the first surface 2121, in other embodiments, one or more of the DOE 2146 and the DOE 2148 can be configured to operate in a reflective mode and can be disposed on the second surface 2122. A cantilevered scanner 2115 is positioned adjacent to a first surface 2121 of the waveguide 2142. A collimated scanning optical element, e.g., a collimated scanning mirror 2130, is positioned adjacent to the first surface of the waveguide on the same side as the cantilevered scanner. A scanning optical element, e.g., a scanning mirror 2120, is positioned adjacent to a second surface of the waveguide. In the waveguide display system 2100, the cantilevered scanner 2115 is configured to be a line scanner, i.e., with one scan axis, and the scanning mirror 2120 is a scanning mirror configured to scan with one scan axis that may be orthogonal to the scan axis of the cantilevered scanner.

[0195] The cantilevered scanner 2115 may include a cantilevered optical member 2110 (or another suitable waveguide scanner). The tip of the cantilevered optical member 2110, which may include a waveguide, may be configured such that the optical axis 2152 of the input light beam 2150 emitted from the tip of the cantilevered optical member 2110 is refracted at an angle α with respect to the extension 2117 of the cantilevered optical member 2110. For example, the end of the waveguide may be cut at an angle such that the tip surface is not perpendicular to the axis of the waveguide, or a waveguide with a tip surface perpendicular to the axis of the waveguide is mounted such that the tip is angled with respect to the long axis of the cantilevered scanner. The collimating mirror 2130 may be a section or piece of a collimating mirror instead of a perfectly round mirror. The cross section of the collimating mirror 2130 may be configured to receive the diverging input light beam 2150 emitted from the tip of the cantilevered optical member 2110. The cantilevered optical element 2110 can scan along an arc in and out of the page. As shown, the normal 2102 of the cross section of the collimating mirror 2130 can be tilted slightly at an angle β with respect to the optical axis 2152 so that the reflected collimated light beam 2160 is directed upward and misses the cantilevered optical element 2110 (instead of being directed back toward the cantilevered optical element 2110). The optical axis 2152 of the diverging input light beam 2150 is incident on the collimating mirror 2130 at an incidence angle β. Because of the tilt angle α, the magnitude of the angle β required to make the collimated light beam 2160 miss the cantilevered optical element 2110 can be smaller. Thus, off-axis aberrations can be reduced as described above in connection with FIGS. 21A and 21B.

[0196] The scanning mirror 2120 is positioned adjacent to a second surface 2122 of the waveguide 2142, on the opposite side of the waveguide from the cantilevered scanner and collimating mirror. The scanning mirror 2120 can be configured to scan in a slow axis perpendicular to the plane of the page. The scanning mirror is configured to receive a collimated light beam 2160 through the in-coupled DOE and provide a scanned reflected light beam 2165 towards the waveguide at a second angle of incidence.

[0197] Similar to the embodiments described above, the diffractive coupling of the incident light beam into the waveguide can be configured to achieve a desired diffractive coupling condition. For example, the incident angle θ of the light beam and the grating period d of the inward coupling DOE 2146 may be selected to achieve a desired diffractive coupling condition, as described above in connection with FIG. 3. In some embodiments, the inward coupling DOE 2146 is configured to prevent the collimated light beam 2160 from propagating to the outward coupling DOE in the waveguide through total internal reflection (TIR). The inward coupling DOE 2146 is also configured to propagate the collimated scanned light beam from the scanning mirror to the outward coupling DOE in the waveguide through total internal reflection (TIR). To facilitate discussion, the direction oriented along the plane of the waveguide extending from the inward coupling DOE 2146 towards the outward coupling DOE 2148 is the “−X” direction, and the opposite direction is the “+X” direction.

[0198] For example, when a collimated light beam 2160 passes through the in-coupled DOE 2146, the negative first order diffraction by the in-coupled DOE 2146 at the diffraction angle on the first pass (in transmission geometry) may lack the TIR condition of the waveguide 2142 towards the out-coupled DOE 2148 in the "-X" direction. In FIG. 21C, lacking the TIR condition, the light beam may propagate along the surface of the waveguide 2142 as an evanescent wave 2162 or may be refracted out of the waveguide 2142 at each bounce within the waveguide 2142, as shown by the dotted line 2164. However, when the collimated reflected light beam 2165 is incident on the in-coupling DOE 2146, the negative first order diffraction by the in-coupling DOE 2146 (in a transmission geometry) may satisfy the TIR condition of the waveguide 2142 towards the out-coupling DOE 2148 in the "-X" direction, as shown by light beam 2166. The out-coupling DOE 2148 may comprise a diffraction grating (which may be referred to herein as an out-coupling grating) configured to diffract a portion of the light beam 2166 out of the waveguide 2142 towards the viewer's eye 2170. To illustrate the light path for image projection, the light beams that are diffracted in the waveguide and emitted to reach the viewer's eye 2170 are marked by grey arrows 2171, 2172, 2173, and 2174. To simplify the drawing, the light beam that is diffracted in the "+X" direction away from the out-coupling DOE 2148 is omitted in Figure 21C. Further details about the selective diffraction function of the in-coupling DOE are described above in connection with Figures 3, 4A, 4B, 5, 6A, and 6B.

[0199] As described above, FIG. 21C illustrates an example of a waveguide display system with a cantilevered scanner providing a diverging light beam integrated with a scanning mirror to provide a two-dimensional scanning light beam. A collimating mirror is then used to produce a collimated light beam for incoupling into the waveguide to form an image. This system allows the light source and the collimating mirror to be placed on the same side of the eyepiece waveguide and the scanning mirror on the other side. Furthermore, the collimating mirror is in the shape of a cross section or a strip to avoid the cantilevered scanner being in the optical path of the light beam reflected from the collimating mirror. One advantage of this configuration is the reduced size of the device. Furthermore, this configuration can be implemented without a polarization-sensitive DOE, a waveplate for modifying the polarization, or a polarization-dependent light source, etc. The complexity and cost of the display system can be substantially reduced.

[0200] FIG 22A is a perspective view illustrating a two-dimensional scanning light source according to some embodiments of the present invention, and FIG 22B is a side view illustrating the two-dimensional scanning light source of FIG 22A. As shown, the two-dimensional scanning light source 2200 includes a cantilevered scanner 2210 configured to provide a scanned light beam 2261 and a reflective optical element 2220 disposed adjacent to the cantilevered scanner 2210 and configured to receive the scanned light beam 2261 and provide a reflected scanned light beam 2262. The two-dimensional scanning light source 2200 also includes a collimating optical element 2230 disposed adjacent to the reflective optical element 2220 and configured to receive the reflected scanned light beam 2262 from the reflective optical element 2220 and provide a collimated scanned light beam 2263. The two-dimensional scanning light source 2200 further includes a scanning optical element 2240 disposed adjacent to the collimating optical element 2230 and configured to receive the collimated scanning light beam 2263 and provide a collimated two-dimensional scanning light beam 2264.

[0201] 22A and 22B, cantilevered scanner 2210 includes a base portion 2211 and a cantilevered optical member 2212 protruding from base portion 2211. Base portion 2211 and cantilevered optical member 2212 can be similar to corresponding components in example cantilevered scanner 1800, described above in connection with FIGS. 18A-18C. Cantilevered optical member 2212 can include a waveguide 2213 for coupling to light source 2214. Light source 2214 can be a laser diode, similar to laser diode 1809, described above in connection with FIGS. 18A-18C. The cantilevered scanner 2210 also includes a scanning mechanism provided by a transducer assembly 2215 having one or more piezoelectric actuators 2216 coupled to the cantilevered optical member 2212 and configured to induce movement (indicated by the sweeping arrow) of the cantilevered optical member 2212 in a first plane 2217 to provide a scanned light beam 2261 that travels back and forth along the width of the reflective optical element 2220. The piezoelectric actuators 2216 may be similar to the piezoelectric film actuators 1814 described above in connection with FIG.

[0202] The base portion 2211 of the cantilevered scanner 2210 includes a layer of material, such as a single crystal silicon layer 2218. The base portion 2211 may also include another silicon layer 2219 that is bonded to the single crystal silicon layer 2218 and provides mechanical support. The cantilevered optical member 2212 includes a cantilever beam that is integrally formed with and projects therefrom. One or more piezoelectric actuators 2216 are each oriented generally parallel to a longitudinal axis 2251 of the cantilevered optical member 2212.

[0203] The collimating optical element 2230 includes a mirror 2232 with positive refractive power. For example, the collimating optical element 2230 can be a concave mirror. In some embodiments, the collimating optical element 2230 is configured to compensate for differences in the light path in the scanning light emitted by the cantilevered optical member 2212. The scanning optical element 2240 is a one-axis scanning mirror that scans in a second scanning plane 2248 (indicated by a sweeping arrow) that is orthogonal to the first scanning plane 2238 of the cantilevered scanner.

[0204] As shown in Figures 22A and 22B, the cantilevered scanner 2210 is configured as a one-dimensional scanner, i.e., with one scanning axis. The scanning optical element 2240 is a scanning mirror, which is configured to scan with one scanning axis, which may be orthogonal to the scanning axis of the cantilevered scanner 2210. In some embodiments, the scanning optical element 2240 can be a MEMS scanning mirror. In alternative embodiments, the scanning optical element 2240 can be a square or triangular shaped structure that always rotates at the same speed and in the same direction, generating a planar image from a 1D cantilevered line scan. The advantage of this approach is duality, i.e., there is no light build-up at the end of each slow pass as the mirror comes to a stop and reverses direction, since the rotating object travels at a constant speed. Furthermore, it will always scan the line in the same direction (go to the bottom of the image and then jump back to the top for the next image) so that the time between refreshes of each pixel is the same.

[0205] In some embodiments, the cantilever scanner 2210, the reflective optical element 2220, the collimating optical element 2230, and the scanning optical element 2240 can be fabricated separately and then assembled into a light source device. In alternative embodiments, the cantilever scanner 2210, the reflective optical element 2220, the collimating optical element 2230, and the scanning optical element 2240 are integrated into a single semiconductor MEMS device, such as a silicon MEMS device, to form an integrated two-dimensional scanning light source. In these embodiments, the scanning cantilever and the scanning mirror are located on the same side of the device and coplanar with each other, so that they can be fabricated from the same silicon part, with cost and complexity savings. As described above, the two-dimensional scanning light source 2200 can be fabricated into a compact device that provides a collimated scanning light source in two dimensions that can be easily integrated into a display system. An example is described below with reference to FIG. 23. In other embodiments, the components can be fabricated separately and assembled into a two-dimensional scanning light source.

[0206] FIG. 23 is a simplified schematic diagram illustrating another waveguide display system including a projector integrated with a scanning mirror, according to some embodiments of the present invention. As shown in FIG. 23, the waveguide display system 2300 includes an eyepiece waveguide 2340 having a planar waveguide 2342 with a first surface 2321 and a second surface 2322. The eyepiece waveguide 2340 also has an in-coupling diffractive optical element (DOE) 2346 coupled to a first lateral region of the waveguide 2342 and an out-coupling DOE 2348 coupled to a second lateral region of the waveguide 2342. Although the in-coupling and out-coupling DOEs are described as being offset laterally, other configurations are possible. For example, the in-coupling DOE may be offset vertically on the waveguide surface or offset at an angle from the out-coupling DOE. A cantilever-based two-dimensional scanning light source 2315 is positioned adjacent to a first surface 2321 of the waveguide 2342 .

[0207] The two-dimensional scanning light source 2315 is similar to the two-dimensional scanning light source 2200 of Figures 22A and 22B, corresponding components are marked with the same reference numbers, and the discussion provided in connection with Figures 22A and 22B is applicable to Figure 23, as appropriate.

[0208] As shown, the two-dimensional scanning light source 2315 includes a cantilevered scanner 2210 configured to provide a scanned light beam 2261 and a reflective optical element 2220 disposed adjacent to the cantilevered scanner 2210 and configured to receive the scanned light beam 2262 and provide a reflected scanned light beam 2222. The two-dimensional scanning light source 2315 also includes a collimating optical element 2230 disposed adjacent to the reflective optical element 2220 and configured to receive the reflected scanned light beam 2262 from the reflective optical element 2220 and provide a collimated scanned light beam 2263. The two-dimensional scanning light source 2200 further includes a scanning optical element 2240 disposed adjacent to the collimating optical element 2230 and configured to receive the collimated scanned light beam 2263 and provide a collimated two-dimensional scanned light beam 2264. Further details of the two-dimensional scanning light source 2315 may be found in the description of the two-dimensional scanning light source 2200 in Figures 22A and 22B and will not be repeated here.

[0209] The waveguide 2342 is configured to receive the collimated two-dimensional scanning light beam 2264 at the inward coupling DOE 2346 and propagate the collimated two-dimensional scanning light beam to the outward coupling DOE 2348 through total internal reflection (TIR). For example, the collimated two-dimensional scanning light beam 2264 is incident on the inward coupling DOE 2346 and satisfies the TIR condition of the waveguide 2342 towards the outward coupling DOE 2348 in the "-X" direction as shown by the light beam 2366. The dimensions of the inward coupling DOE 2346 can be selected such that all angles of light scanned by the scanning optical element 2240 towards the waveguide are incident on the inward coupling DOE 2346. In some embodiments, the inward coupling DOE 2346 is extended laterally. The out-coupling DOE 2348 may include a diffraction grating (which may be referred to herein as an out-coupling grating) configured to diffract a portion of the light beam 2366 out of the waveguide 2342 towards the viewer's eye 2350. To illustrate the light path for image projection, the light beams that are diffracted within the waveguide and emitted to reach the viewer's eye 2350 are marked by grey arrows 2371, 2372, 2373, and 2374.

[0210] 23, the components of the two-dimensional scanning light source 2315, including the cantilevered scanner 2210, the reflective optical element 2220, the collimating optical element 2230, and the scanning optical element 2240, are disposed on the same side of the waveguide adjacent the first surface 2321. In an alternative embodiment, the two-dimensional scanning light source 2315 can also be disposed adjacent the second surface 2322 of the waveguide 2342, with the angle of incidence of the collimated two-dimensional scanning light beam 2264 being selected such that the collimated two-dimensional scanning light beam 2264 is received at the in-coupling DOE 2346 and propagated through total internal reflection (TIR) ​​to the out-coupling DOE 2348. The appropriate angle of incidence can be selected using the techniques described above in connection with various configurations of the waveguide display system.

[0211] It should also be understood that the examples and embodiments described herein are for illustrative purposes only, and that various modifications or changes in light thereof will be suggested to those skilled in the art and are within the spirit and scope of the present application and the appended claims.

Claims

1. 1. A waveguide display system comprising: a waveguide having a first surface and a second surface, the waveguide including an in-coupling diffractive optical element (DOE) and an out-coupling DOE; a point light source disposed adjacent the first surface of the waveguide, the point light source configured to provide a diverging input light beam to a portion of the waveguide outside the in-coupling DOE; a scanning mirror disposed adjacent to the second surface of the waveguide, the scanning mirror configured to receive the diverging input light beam from the point source through the waveguide and to provide a diverging reflected light beam towards the in-coupled DOE of the waveguide; a collimating scanning optical element positioned adjacent to the first surface of the waveguide, the collimating scanning optical element configured to receive the diverging reflected light beam emitted from the scanning mirror through the waveguide in-coupling DOE and produce a collimated reflected light beam that propagates towards the waveguide in-coupling DOE; Equipped with The internally coupled DOE is preventing the diverging reflected light beam from the scanning mirror from propagating through total internal reflection (TIR) ​​to the out-coupled DOE in the waveguide; propagating the collimated reflected light beam within the waveguide to the out-coupled DOE through total internal reflection (TIR); A waveguide display system configured to:

2. 10. The waveguide display system of claim 1, wherein the incoupling DOE is a periodic grating having a pitch configured to selectively incoupling light beams of different angles of incidence.

3. 2. The waveguide display system of claim 1, wherein the point light source comprises a fiber point source including an optical fiber having a tip with an angled facet, the optical fiber configured to emit a light beam in a direction at an angle relative to an axis of the optical fiber.

4. 2. The waveguide display system of claim 1, wherein the incidence angle of the diverging input light beam, the collimated reflected light beam, and the grating period of the internal coupling DOE are configured to determine a diffraction angle such that the diverging input light beam transmitted through the internal coupling DOE does not satisfy the TIR condition for the diverging input light beam to propagate to the external coupling DOE, and the collimated reflected light beam reaching the internal coupling DOE satisfies the TIR condition for propagating to the external coupling DOE.

5. diffraction of the diverging input light beam by the in-coupling DOE results in a first negative first order diffracted light beam that lacks a total internal reflection (TIR) ​​condition of the waveguide; 2. The waveguide display system of claim 1, wherein diffraction of the collimated reflected light beam by the in-coupling DOE results in a second negative first order diffracted light beam that satisfies the TIR condition of the waveguide.

6. 10. The waveguide display system of claim 1, wherein the diverging input light beam, the diverging reflected light beam, and the collimated reflected light beam are incident on the waveguide at an angle relative to a normal to the waveguide.

7. 10. The waveguide display system of claim 1, wherein the out-coupling DOE comprises a diffraction grating configured to diffract a portion of the collimated reflected light beam out of the waveguide.

8. 1. A waveguide display system comprising: a waveguide having a first surface and a second surface, the waveguide including an in-coupling diffractive optical element (DOE) and an out-coupling DOE; a cantilever scanner disposed adjacent the first surface of the waveguide, the cantilever scanner configured to provide a scanned light beam; a reflective optical element disposed adjacent to the cantilever scanner, the reflective optical element configured to receive the scanning light beam and provide a reflected scanning light beam; a collimating optical element disposed adjacent to the reflective optical element and configured to receive the reflected scanning light beam from the reflective optical element and provide a collimated scanning light beam; a scanning optical element disposed adjacent to the collimating optical element and configured to receive the collimated scanning light beam and provide a collimated two-dimensional scanning light beam; Equipped with the cantilevered scanner, the reflective optical element, the collimating optical element, and the scanning optical element are disposed on a same side of the waveguide adjacent the first surface; The waveguide display system is configured to receive the collimated two-dimensional scanning light beam at the in-coupling DOE and propagate the collimated two-dimensional scanning light beam to the out-coupling DOE through total internal reflection (TIR).

9. The cantilever scanner includes: A base portion; a cantilevered optical member protruding from the base portion, the cantilevered optical member including a waveguide for coupling to a light source; a transducer assembly comprising one or more piezoelectric actuators coupled to the cantilevered optical member and configured to induce movement of the cantilevered optical member in a first scan plane to provide the scanned light beam; 9. The waveguide display system of claim 8 comprising:

10. 9. The waveguide display system of claim 8, wherein the collimating optical element comprises a mirror with positive optical power (e.g., a concave mirror).

11. 9. The waveguide display system of claim 8, wherein the scanning optical element is a one-axis scanning mirror that scans in a direction perpendicular to a scan direction of the cantilever scanner.

12. The waveguide display system of claim 8 , wherein the cantilevered scanner, the reflective optical element, the collimating optical element, and the scanning optical element are positioned on the same side of the waveguide adjacent to the first surface.

13. The waveguide display system of claim 8 , wherein the cantilevered scanner, the reflective optical element, the collimating optical element, and the scanning optical element are positioned on the same side of the waveguide adjacent to the second surface.

14. 9. The waveguide display system of claim 8, wherein the scanning optical element comprises a square or triangular shaped structure that always rotates at the same speed and in the same direction to generate a planar image from a one-dimensional line scan.

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