Grating waveguide combiner for optical engine

Patent metadata

Field	Value
Publication number	US-10656426-B2
Application number	US-201816231328-A
Country	US
Kind code	B2
Filing date	Dec 21, 2018
Priority date	Dec 22, 2017
Publication date	May 19, 2020
Grant date	May 19, 2020

Abstract

Systems, devices, and methods of manufacturing optical engines and laser projectors that are well-suited for use in wearable heads-up displays (WHUDs) are described. Generally, the optical engines of the present disclosure integrate a plurality of laser diodes (e.g., 3 laser diodes, 4 laser diodes) within a single, hermetically or partially hermetically sealed, encapsulated package. A grating waveguide combiner comprising a plurality of waveguides having grating couplers thereon may be used to combine beams of light emitted by the plurality of laser diodes into a coaxially superimposed aggregate beam. Such optical engines may have advantages over existing designs including, for example, smaller volumes, better manufacturability, faster modulation speed, etc. WHUDs that employ such optical engines and laser projectors are also described.

First claim

The invention claimed is:

1. A wearable heads-up display (WHUD), comprising:
a support structure that in use is worn on the head of a user;
a laser projector carried by the support structure, the laser projector comprising:
an optical engine, comprising:
a base substrate;
a plurality of laser diodes, each of the plurality of laser diodes bonded directly or indirectly to the base substrate;
at least one laser diode driver circuit operatively coupled to the plurality of laser diodes to selectively drive current to the plurality of laser diodes;
a plurality of collimation lenses, each of the plurality of collimation lenses positioned proximate a respective one of the plurality of laser diodes collimates light emitted therefrom;
a cap comprising at least one wall and at least one optical window that, together with the base substrate, define an interior volume sized and dimensioned to receive at least the plurality of laser diodes and the plurality of collimation lenses, the cap being bonded to the base substrate to provide a hermetic or partially hermetic seal between the interior volume of the cap and a volume exterior to the cap, and the optical window positioned and oriented to allow beams of light emitted from the plurality of laser diodes through the collimation lenses to exit the interior volume; and
a grating waveguide combiner positioned proximate the optical window of the cap, the grating waveguide combiner comprising a plurality of input grating couplers and at least one output grating coupler, in operation, the grating waveguide combiner receives a plurality of beams of light at the respective plurality of input grating couplers and combines the plurality of beams of light to provide a collimated aggregated beam of light at the output grating coupler; and

at least one scan mirror positioned to receive the aggregate beam of light output at the output grating coupler of the grating waveguide combiner, the at least one scan mirror controllably orientable to redirect the aggregate beam of light over a range of angles.

2. The WHUD of claim 1 , further comprising a processor communicatively coupled to the laser projector to modulate the generation of light signals.

3. The WHUD of claim 1 , further comprising:
a transparent combiner carried by the support structure and positioned within a field of view of the user, in operation the transparent combiner directs laser light from an output of the laser projector into the field of view of the user.

4. An optical engine, comprising:
a base substrate;
a plurality of laser diodes, each of the plurality of laser diodes bonded directly or indirectly to the base substrate;
at least one laser diode driver circuit operatively coupled to the plurality of laser diodes to selectively drive current to the plurality of laser diodes;
a plurality of collimation lenses, each of the plurality of collimation lenses positioned proximate a respective one of the plurality of laser diodes collimates light emitted therefrom;
a cap comprising at least one wall and at least one optical window that, together with the base substrate, define an interior volume sized and dimensioned to receive at least the plurality of laser diodes and the plurality of collimation lenses, the cap being bonded to the base substrate to provide a hermetic or partially hermetic seal between the interior volume of the cap and a volume exterior to the cap, and the optical window positioned and oriented to allow beams of light emitted from the plurality of laser diodes through the collimation lenses to exit the interior volume; and
a grating waveguide combiner positioned proximate the optical window of the cap, the grating waveguide combiner comprising a plurality of input grating couplers and at least one output grating coupler, in operation, the grating waveguide combiner receives a plurality of beams of light at the respective plurality of input grating couplers and combines the plurality of beams of light to provide a collimated aggregated beam of light at the output grating coupler.

5. The optical engine of claim 4 wherein the grating waveguide combiner comprises a first grating waveguide and a second grating waveguide.

6. The optical engine of claim 5 wherein each of the first and second grating waveguides includes at least two input grating couplers.

7. The optical engine of claim 4 wherein the grating waveguide combiner comprises at least four waveguides.

8. The optical engine of claim 4 wherein the plurality of collimation lenses are formed as a micro-optic lens array.

9. The optical engine of claim 4 wherein the plurality of collimation lenses are bonded to the base substrate.

10. The optical engine of claim 4 wherein the grating waveguide combiner is bonded to the base substrate proximate the optical window of the cap.

11. The optical engine of claim 4 , further comprising:
a common collimation lens positioned and oriented to receive and collimate the aggregate beam of light from the output grating coupler of the grating waveguide combiner.

12. The optical engine of claim 11 wherein the common collimation lens comprises an achromatic lens or an apochromatic lens.

13. The optical engine of claim 4 , further comprising at least one diffractive optical element positioned and oriented to receive the aggregate beam of light, in operation, the at least one diffractive optical element provides wavelength dependent focus correction for the aggregate beam of light.

14. The optical engine of claim 4 , further comprising:
a plurality of chip submounts bonded to the base substrate, wherein each of the laser diodes are bonded to a corresponding one of the plurality of chip submounts.

15. The optical engine of claim 4 wherein the plurality of laser diodes includes a red laser diode to provide a red laser light, a green laser diode to provide a green laser light, a blue laser diode to provide a blue laser light, and an infrared laser diode to provide infrared laser light.

16. The optical engine of claim 4 wherein the at least one laser diode driver circuit is bonded to a first surface of the base substrate, and the plurality of laser diodes and the cap are bonded to a second surface of the base substrate, the second surface of the base substrate opposite the first surface of the base substrate.

17. The optical engine of claim 4 wherein the at least one laser diode driver circuit, the plurality of laser diodes, and the cap are bonded to a first surface of the base substrate.

18. The optical engine of claim 4 wherein the plurality of laser diodes and the cap are bonded to the base substrate, and the at least one laser diode driver circuit is bonded to another substrate separate from the base substrate.

19. The optical engine of claim 4 wherein each of the laser diodes comprises one of an edge emitter laser or a vertical-cavity surface-emitting laser (VCSEL).

20. A laser projector, comprising:
an optical engine, comprising:
a base substrate;
a plurality of laser diodes, each of the plurality of laser diodes bonded directly or indirectly to the base substrate;
at least one laser diode driver circuit operatively coupled to the plurality of laser diodes to selectively drive current to the plurality of laser diodes;
a plurality of collimation lenses, each of the plurality of collimation lenses positioned proximate a respective one of the plurality of laser diodes collimates light emitted therefrom;
a cap comprising at least one wall and at least one optical window that, together with the base sub

Assignees

• North Inc

Inventors

• Pierer Jörg
• James Rony Jose
• Mohrdiek Stefan
• Kiik Martin Joseph
• Haque Syed Moez
• Dykaar Douglas Raymond

Classifications

• G02B6/124

  Geodesic lenses or integrated gratings · CPC title

• G02B27/0176 Primary

  characterised by mechanical features · CPC title

• G02B26/101

  with both horizontal and vertical deflecting means, e.g. raster or XY scanners (colour television using laser beams scanning a display screen H04N9/3129) · CPC title

• G02B6/4214

  the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device (G02B6/4246 takes precedence) · CPC title

• G02B2006/12164

  Multiplexing; Demultiplexing · CPC title