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EP-4740051-A1 - PROJECTOR COMPENSATION WITH IN-COUPLER GRATING LINE OFFSET

EP4740051A1EP 4740051 A1EP4740051 A1EP 4740051A1EP-4740051-A1

Abstract

Certain aspects of the present disclosure include an optical device. The optical device generally includes an in-coupler (IC) configured to receive light from a projector, where the IC includes at least one grating line offset (GLO) associated with one or more phase deviations of the light from the projector. The device also includes a waveguide and an output coupler (OC), where the IC is configured to redirect the light from the projector to the OC through the waveguide.

Inventors

  • Wang, Evan
  • SELL, DAVID ALEXANDER
  • MESSER, Kevin

Assignees

  • Applied Materials, Inc.

Dates

Publication Date
20260513
Application Date
20240703

Claims (20)

  1. 1. An optical device, comprising: an in-coupler (IC) configured to receive light from a projector, wherein the IC includes at least one grating line offset (GLO) associated with one or more phase deviations of the light from the projector; a waveguide; and an output coupler (OC), wherein the IC is configured to redirect the light from the projector to the OC through the waveguide.
  2. 2. The optical device of claim 1 , wherein the at least one GLO comprises different GLOs applied to at least two grating lines of the IC.
  3. 3. The optical device of claim 1 , wherein the at least one GLO is determined based on an average of the phase deviations of the light.
  4. 4. The optical device of claim 1 , wherein different weights are applied for different wavelengths of the light or field of views (FOVs) associated with the optical device, and wherein the at least one GLO of the IC is determined based on the different weights.
  5. 5. The optical device of claim 4, wherein the different weights are determined based on a contribution of the different wavelengths or FOVs to a modulation transfer function of the optical device.
  6. 6. The optical device of claim 1 , wherein the at least one GLO is an offset of a grating line of the IC from a grating line of an IC having periodic grating lines.
  7. 7. The optical device of claim 1 , wherein the at least one GLO is associated with a determined phase shift to be applied to the light to reduce effects of the one or more phase deviations in one or more image metrics.
  8. 8. A method for optical signal processing, comprising: receiving, via an in-coupler (IC), light from a projector; applying at least one phase shift to the light via the IC, wherein, to apply the at least one phase shift, the IC includes at least one grating line offset (GLO) associated with one or more phase deviations of the light from the projector; and redirecting, via the IC, the light from the projector to an out-coupler (OC) through a waveguide.
  9. 9. The method of claim 8, wherein the at least one GLO comprises different GLOs applied to at least two grating lines of the IC.
  10. 10. The method of claim 8, wherein the at least one GLO is determined based on an average of the phase deviations of the light.
  11. 11. The method of claim 8, wherein different weights are applied for different wavelengths of the light or field of views (FOVs) associated with an optical device, and wherein the at least one GLO of the IC is determined based on the different weights.
  12. 12. The method of claim 11 , wherein the different weights are determined based on a contribution of the different wavelengths or FOVs to a modulation transfer function of the optical device.
  13. 13. The method of claim 8, wherein the at least one GLO comprises an offset of a grating line of the IC from a grating line of an IC having periodic grating lines.
  14. 14. The method of claim 8, wherein the at least one GLO is associated with a determined phase shift to be applied to the light to reduce an effect of the one or more phase deviations in one or more image metrics.
  15. 15. An augmented reality (AR) device, comprising: a projector; an in-coupler (IC) configured to receive light from the projector, wherein the IC includes at least one grating line offset (GLO) associated with one or more phase deviations of the light from the projector; a waveguide; and an output coupler (OC), wherein the IC is configured to redirect the light from the projector to the OC through the waveguide.
  16. 16. The AR device of claim 15, wherein the at least one GLO comprises different GLOs applied to at least two grating lines of the IC.
  17. 17. The AR device of claim 15, wherein the at least one GLO is determined based on an average of the phase deviations of the light.
  18. 18. The AR device of claim 15, wherein different weights are applied for different wavelengths of the light or field of views (FOVs) associated with the AR device, and wherein the at least one GLO of the IC is determined based on the different weights.
  19. 19. The AR device of claim 18, wherein the different weights are determined based on a contribution of the different wavelengths or FOVs to a modulation transfer function of the AR device.
  20. 20. The AR device of claim 15, wherein the at least one GLO is an offset of a grating line of the IC from a grating line of an IC having periodic grating lines.

Description

PROJECTOR COMPENSATION WITH IN-COUPLER GRATING LINE OFFSET BACKGROUND Field [0001] Certain aspects of the present disclosure generally relate to a waveguide display. More particularly, the present disclosure provides a waveguide having an incoupler implemented with projector compensation. Description of the Related Art [0002] Augmented reality (AR) is a technology that blends virtual and physical worlds to provide users with immersive experiences. Creating a virtual image that appears integrated with the real environment is important for the AR display. AR may be implemented with a waveguide including an in-coupler (IC) and an out-coupler (OC), where the IC redirects light from a projector towards an OC, and the OC redirects light towards a user’s eye. SUMMARY [0003] Certain aspects of the present disclosure include an optical device. The optical device generally includes an in-coupler (IC) configured to receive light from a projector, where the IC includes at least one grating line offset (GLO) associated with one or more phase deviations of the light from the projector. The device also includes a waveguide and an output coupler (OC), where the IC is configured to redirect the light from the projector to the OC through the waveguide. [0004] Certain aspects of the present disclosure include a method for optical signal processing. The method generally includes receiving, via an IC, light from a projector. The method also includes applying at least one phase shift to the light via the IC, where, to apply the at least one phase shift, the IC includes at least one GLO associated with one or more phase deviations of the light from the projector. The method may also include redirecting, via the IC, the light from the projector to an OC through a waveguide. BRIEF DESCRIPTION OF THE DRAWINGS [0005] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments of the present disclosure and are therefore not to be considered limiting of scope, and may admit to other equally effective embodiments. [0006] Figure 1 illustrates an optical device having a waveguide and an in-coupler (IC), in accordance with certain aspects of the present disclosure. [0007] Figure 2A illustrates phase deviations of light from a projector. [0008] Figure 2B illustrates a GLO implemented for an IC to reduce effects of phase deviations in light from a projector, in accordance with certain aspects of the present disclosure. [0009] Figure 3 is a flow diagram illustrating example operations for optical signal processing, in accordance with certain aspects of the present disclosure. [0010] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other aspects without further recitation. DETAILED DESCRIPTION [0011] An in-coupler (IC) of a waveguide combiner diffracts light from a projector into total internal reflection (TIR) (e.g., total internal reflection within a medium, such as the waveguide). Some aspects are directed towards shifting the grating lines across the IC, resulting in a spatially varying phase applied to the diffracted light from the projector. The phase shift may be used to compensate for the effects of imperfections in the projector output. As used herein, compensation refers to any reduction in the effects of the imperfections and does not require complete compensation for such effects. [0012] Augmented reality (AR) waveguide combiners may be designed assuming the projector output is a plane wave with a flat wavefront. This is often not the case in real projectors, and any deviations from the flat wavefront may degrade the system’s modulation transfer function (MTF) or sharpness. MTF refers to the optical device’s capability to transfer an object’s contrast from an input of the optical device to an output of the optical device. From the user’s perspective, the deviations may manifest as a blurry virtual image and inhibit the readability of small text or lines. Certain aspects reduce the effects of such deviations from the flat wavefront by implementing a grating line offset (GLO) for an IC for the waveguide. [0013] Figure 1 illustrates an optical device 100 having a waveguide 110 and an IC 106, in accordance with certain aspects of the present disclosure. As shown, light 104 may be received from a projector 102. The light 104 may be directed towards an IC 106. The IC 106 redirects the light into TIR within the waveguide 110 until the light 104 reaches an OC 108. The OC 108 may redirect the light toward a user 112, as shown.