WAVEGUIDE GRATINGS TO IMPROVE INTENSITY DISTRIBUTIONS

• US 20170131546A1
• Filed: 11/10/2015
• Published: 05/11/2017
• Est. Priority Date: 11/10/2015
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Pasi Kostamo
• Inventors: Woltman, Scott, Robbins, Steven John, Wall, R. Andrew, Vallius, Tuomas, Levola, Tapani, Kostamo, Pasi
• Granted Patent: US 9,791,696 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/0123 comprising devices increasing the field of view
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 27/0081 with means for altering, e.g. enlarging, the entrance or exit pupil
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/0103 comprising holographic elements
• CPC Class Codes: G02B 27/4205 having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant
• CPC Class Codes: G02B 5/1866 Transmission gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials G02B5/1809, G02B5/1828, G02B5/1833, G02B5/1838 and G02B5/1847 take precedence
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements

Abstract

An apparatus for use in replicating an image associated with an input-pupil to an output-pupil includes a planar optical waveguide including a bulk-substrate, and also including an input-coupler, an intermediate-component and an output-coupler. The input-coupler couples light corresponding to the image into the bulk-substrate and towards the intermediate-component. The intermediate-component performs horizontal or vertical pupil expansion and directs the light corresponding to the image towards the output-coupler. The output-coupler performs the other one of horizontal or vertical pupil expansion and couples light corresponding to the image, which travels from the input-coupler to the output-coupler, out of the waveguide. In certain embodiments, one or more of the input-coupler, the intermediate-component or the output-coupler comprises a liquid crystal polymer (LCP) based surface relief grating (SRG) or a double-side diffractive optical element (DOE), each of which can be used to improve an intensity distribution of light output by the output-coupler.

Claims

1. An apparatus for use in replicating an image associated with an input-pupil to an output-pupil, the apparatus comprising:

a planar optical waveguide including a bulk-substrate, and also including an input-coupler, an intermediate-component and an output-coupler;

the input-coupler configured to couple light corresponding to the image associated with the input-pupil into the bulk-substrate of the waveguide and towards the intermediate-component;

the intermediate-component configured to perform one of horizontal or vertical pupil expansion and to direct the light corresponding to the image towards the output-coupler; and

the output-coupler configured to perform the other one of horizontal or vertical pupil expansion and to couple the light corresponding to the image, which travels in the planar optical waveguide from the input-coupler to the output-coupler, out of the waveguide so that the light is output and imaged from the output-pupil;

wherein one or more of the input-coupler, the intermediate-component or the output-coupler comprises as a surface relief grating (SRG) that is formed in a liquid crystal polymer (LCP) coating.

2. The apparatus of claim 1, wherein:

the bulk-substrate includes a first major planar surface and a second major planar surface opposite and parallel to the first major planar surface; and

the LCP coating, in which the one or more of the input-coupler, the intermediate-component or the output-coupler is formed as an SRG, covers one of the first and second major planar surfaces of the bulk-substrate.

3. The apparatus of claim 1, wherein the one or more of the input-coupler, the intermediate-component or the output-coupler that is formed as an SRG in the LCP coating is configured to rotate a polarization of light that is incident thereon.

4. The apparatus of claim 1, wherein each one of the input-coupler, the intermediate-component and the output-coupler is formed as an SRG in the LCP coating.

5. The apparatus of claim 4, wherein:

the bulk-substrate including a first major planar surface and a second major planar surface opposite and parallel to the first major planar surface; and

the LCP coating, in which each one of the input-coupler, the intermediate-component and the output-coupler is formed as an SRG, covers a same one of the first and second major planar surfaces of the bulk-substrate.

6. The apparatus of claim 1, wherein the intermediate-component comprises an SRG that is formed in an LCP coating, which mitigate adverse effects of multiple-loop interference that would be caused by the intermediate-component if the intermediate-component were an SRG formed in or on an isotropic material.

7. An apparatus for use in replicating an image associated with an input-pupil to an output-pupil, the apparatus comprising:

a planar optical waveguide including a bulk-substrate, and also including an input-coupler, an intermediate-component and an output-coupler;

the input-coupler configured to couple light corresponding to the image associated with the input-pupil into the bulk-substrate of the waveguide and towards the intermediate-component;

the intermediate-component configured to perform one of horizontal or vertical pupil expansion and to direct the light corresponding to the image towards the output-coupler; and

the output-coupler configured to perform the other one of horizontal or vertical pupil expansion and to couple the light corresponding to the image, which travels in the planar optical waveguide from the input-coupler to the output-coupler, out of the waveguide so that the light is output and imaged from the output-pupil;

wherein one or more of the input-coupler, the intermediate-component or the output-coupler comprises a double-sided diffractive optical element (DOE).

8. The apparatus of claim 7, wherein:

the bulk-substrate includes a first major planar surface and a second major planer surface opposite and parallel to the first major planar surface; and

each said double-sided DOE comprises a first grating that is formed in or on the first major planar surface of the bulk-substrate and a corresponding second grating that is formed in or on the second major planar surface of the bulk-substrate.

9. The apparatus of claim 8, wherein for each said double-sided DOE, the grating period and orientation of the first and second gratings of the double-sided DOE, which are formed respectively in or on the first and second major planar surfaces of the bulk-substrate, are matched to one another.

10. The apparatus of claim 9, wherein for each said double-sided DOE, the first and second gratings of the double-sided DOE comprise surface relief gratings (SRGs).

11. The apparatus of claim 10, wherein for each said double-sided DOE, at least one of the SRGs comprises an SRG that is formed in a liquid crystal polymer (LCP) coating.

12. The apparatus of claim 8, wherein for at least one said double-sided DOE, at least one of the first and second gratings of the double-sided DOE comprises a liquid crystal polymer (LCP) based surface relief grating (SRG).

13. The apparatus of claim 8, wherein for at least one said double-sided DOE, one of the first and second gratings comprises a transmissive grating, and the other comprises a reflective grating.

14. The apparatus of claim 8, wherein the intermediate-component comprises a said double-sided DOE, and wherein the first and second gratings of the intermediate-component comprise reflective gratings.

15. The apparatus of claim 7, wherein each one of the input-coupler, the intermediate-component and the output-coupler comprises a said double-sided DOE.

16. A see-through, mixed reality display device system, comprising:

a display engine configured to produce an image; and

a planar optical waveguide including a bulk-substrate, and also including an input-coupler, an intermediate-component and an output-coupler any one of each of which is either formed in, on or embedded within the bulk-substrate;

the input-coupler configured to couple light corresponding to the image into the bulk-substrate of the waveguide and towards the intermediate-component;

the intermediate-component configured to perform one of horizontal or vertical pupil expansion and to direct the light corresponding to the image towards the output-coupler;

the output-coupler configured to perform the other one of horizontal or vertical pupil expansion and to couple the light corresponding to the image, which travels in the planar optical waveguide from the input-coupler to the output-coupler, out of the waveguide;

the bulk-substrate includes a first major planar surface and a second major planar surface opposite and parallel to the first major planar surface;

wherein one or more of the input-coupler, the intermediate-component or the output-coupler comprises a double-sided diffractive optical element (DOE); and

wherein each said double-sided DOE comprises a first grating that is formed in or on the first major planar surface of the bulk-substrate and a corresponding second grating that is formed in or on the second major planar surface of the bulk-substrate.

17. The system of claim 16, wherein for each said double-sided DOE, the grating period and orientation of the first and second gratings of the double-sided DOE, which are formed respectively in or on the first and second major planar surfaces of the bulk-substrate, are matched to one another.

18. The system of claim 17, wherein for each said double-sided DOE, the first and second gratings of the double-sided DOE comprise surface relief gratings (SRGs).

19. The system of claim 18, wherein for each said double-sided DOE, at least one of the SRGs comprises a liquid crystal polymer (LCP) based SRG.

20. The system of claim 16, wherein each one of the input-coupler, the intermediate-component and the output-coupler comprises a said double-sided DOE.