Vertical emitters with integral microlenses

Patent metadata

Field	Value
Publication number	US-11469573-B2
Application number	US-202016779609-A
Country	US
Kind code	B2
Filing date	Feb 2, 2020
Priority date	Feb 4, 2019
Publication date	Oct 11, 2022
Grant date	Oct 11, 2022

Abstract

An optoelectronic device includes a semiconductor substrate having first and second faces. A first array of emitters are formed on the first face of the semiconductor substrate and are configured to emit respective beams of radiation through the substrate. Electrical connections are coupled to actuate selectively first and second sets of the emitters in the first array. A second array of microlenses are formed on the second face of the semiconductor substrate in respective alignment with the emitters in at least one of the first and second sets and are configured to focus the beams emitted from the emitters in the at least one of the first and second sets so that the beams are transmitted from the second face with different, respective first and second focal properties.

First claim

The invention claimed is:

1. An optoelectronic device, comprising:
a semiconductor substrate having first and second faces;
an emitter array comprising first and second sets of emitters, which are formed on the first face of the semiconductor substrate and are configured to emit respective first and second beams of radiation through the substrate;
electrical connections, which are coupled to actuate selectively the first and second sets of the emitters in the emitter array; and
a microlens array comprising microlenses, which are formed on the second face of the semiconductor substrate in respective alignment with the emitters in at least one of the first and second sets and are configured to focus the beams emitted from the emitters in the at least one of the first and second sets so that the first and second beams are transmitted from the second face with different, respective first and second focal properties.

2. The device according to claim 1 , wherein the semiconductor substrate comprises a III-V semiconductor substrate, and wherein the device comprises a silicon substrate on which the electrical connections are formed, the electrical connections comprising bonding pads to which the emitters in the first array are respectively connected.

3. The device according to claim 1 , wherein the emitters comprise vertical-cavity surface-emitting lasers (VCSELs).

4. An optoelectronic device, comprising:
a semiconductor substrate having first and second faces;
an emitter array comprising emitters, which are formed on the first face of the semiconductor substrate and are configured to emit respective beams of radiation through the substrate;
electrical connections, which are coupled to actuate selectively first and second sets of the emitters in the emitter array; and
a microlens array comprising microlenses, which are formed on the second face of the semiconductor substrate in respective alignment with the emitters in at least one of the first and second sets and are configured to focus the beams emitted from the emitters in the at least one of the first and second sets so that the beams are transmitted from the second face with different, respective first and second focal properties; and
projection optics, which are configured to focus the beams from the emitters in the first set to form a pattern of structured light in an area of a far field while spreading the beams from the emitters in the second set so as to project flood illumination over the area.

5. The device according to claim 4 , wherein the emitters in the first set are disposed across the semiconductor substrate in a predefined spatial distribution, and wherein the pattern of structured light comprises a pattern of spots reproducing the spatial distribution of the emitters in the first set.

6. The device according to claim 4 , wherein the microlenses are formed only in alignment with the emitters in the second set.

7. The device according to claim 4 , wherein the microlenses that are formed in alignment with the emitters in the second set are displaced transversely on the second face relative to respective ones of the emitters in the second set so as to focus the beams emitted from the emitters in the second set toward a peripheral region of a focal plane of the device, and wherein the projection optics comprises a diffuser disposed in the peripheral region of the focal plane and configured to spread the beams that pass through the peripheral region, while the beams that pass through a central region of the focal plane are not diffused.

8. The device according to claim 7 , wherein the projection optics comprise a diffractive optical element (DOE), which is disposed in a central region of the focal plane and is configured to create multiple replicas of the pattern of structured light in the far field.

9. The device according to claim 1 , wherein the microlenses in the second array comprise doublet lenses.

10. An optical device, comprising:
a semiconductor substrate having a first face and a second face, which is etched to define a first array of first microlenses configured to focus optical radiation that has been transmitted through the substrate; and
a second array of second microlenses, which is disposed on the substrate over the first array in alignment with the first microlenses so as to form microlens doublets.

11. The device according to claim 10 , wherein the semiconductor substrate comprises a III-V semiconductor substrate.

12. The device according to claim 10 , and comprising a third array of emitters, which are formed on the first face of the semiconductor substrate in alignment with the first microlenses and are configured to emit respective beams of the optical radiation through the substrate.

13. The device according to claim 12 , wherein the emitters comprise vertical-cavity surface-emitting lasers (VCSELs), and wherein the first and second microlenses are configured to focus multiple modes of each of the VCSELs to a respective beam waist outside the semiconductor substrate.

14. The device according to claim 10 , wherein the second microlenses comprise a polymer.

15. The device according to claim 10 , wherein the second microlenses comprise a glass.

16. The device according to claim 10 , wherein the second microlenses are offset in a transverse direction along the second face relative to the first microlenses with which they are respectively aligned.

17. A method for manufacturing an optical device, the method comprising:
etching a semiconductor substrate, having a first face and a second face, to define, on the second face, a first array of first microlenses configured to focus optical radiation that has been transmitted through the substrate; and
depositing a second array of second microlenses over the first array in alignment with the first microlenses so as to form microlens doublets.

18. The method according to claim 17 , wherein depositing the second microlenses comprises molding a polymer over the second face to define the second microlenses.

19. The method according to claim 17 , wherein depositing the second microlenses comprises applying a photolithographic process to a polymer layer extending over the second face to define the second microlenses.

20. The method according to claim 17 , wherein depositing the second microlenses comprises detecting a misalignment between the first microlenses and emitters of the optical radiation disposed on the first face of the semiconductor substrate, and offsetting the second microlenses in a transverse direction along the second face relative to the first microlenses so as to compensate for the detected misalignment.

Assignees

• Apple Inc

Inventors

• Lyon Keith
• Laflaquiere Arnaud

Classifications

• H01S5/18388 Primary

  Lenses · CPC title

• G02B27/0961

  Lens arrays (lens arrays per se G02B3/0006) · CPC title

• H01S5/021

  Silicon based substrates · CPC title

• H01S5/18305

  with emission through the substrate, i.e. bottom emission · CPC title

• H01S5/026

  Monolithically integrated components, e.g. waveguides, monitoring photo-detectors, drivers (stabilisation of output H01S5/06) · CPC title