Top-emission VCSEL-array with integrated diffuser

Patent metadata

Field	Value
Publication number	US-10295145-B2
Application number	US-201816055104-A
Country	US
Kind code	B2
Filing date	Aug 5, 2018
Priority date	Jun 23, 2016
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

A radiation source includes a semiconductor substrate, an array of vertical-cavity surface-emitting lasers (VCSELs) formed on the substrate, which are configured to emit optical radiation, and a transparent crystalline layer formed over the array of VCSELs. The transparent crystalline layer has an outer surface configured to diffuse the radiation emitted by the VCSELs.

First claim

The invention claimed is:

1. A radiation source, comprising:
a semiconductor substrate;
an array of vertical-cavity surface-emitting lasers (VCSELs) formed on the substrate, which are configured to emit optical radiation; and
a crystalline layer formed over the array of VCSELs and having an outer surface patterned to define microlenses arrayed in an irregular pattern and having different, respective optical powers so as to diffuse the radiation emitted by the VCSELs.

2. The radiation source according to claim 1 , wherein the crystalline layer is transparent.

3. The radiation source according to claim 1 , wherein the outer surface of the crystalline layer is randomly roughened.

4. The radiation source according to claim 1 , wherein the crystalline layer comprises an epitaxial layer of a semiconductor material.

5. The radiation source according to claim 4 , wherein the array of VCSELs comprises multiple epitaxial layers formed on the substrate, and wherein the epitaxial layer of the semiconductor material matches one of the epitaxial layers of the VCSELs.

6. The radiation source according to claim 4 , and comprising anode contacts electrically connected to the VCSELs through the crystalline layer.

7. The radiation source according to claim 1 , wherein the crystalline layer comprises a dielectric material.

8. A method of manufacturing a radiation source, the method comprising:
forming an array of vertical-cavity surface-emitting lasers (VCSELs) on a semiconductor substrate;
forming a crystalline layer over the VCSEL array; and
etching an outer surface of the crystalline layer to create a surface structure that comprises microlenses arrayed in an irregular pattern and having different, respective optical powers and thereby diffuses optical radiation emitted by the VCSELs.

9. The method according to claim 8 , wherein etching the outer surface comprises:
forming a photoresist layer over the crystalline layer;
photolithographically patterning the photoresist layer so as to define precursors for microlenses;
baking the patterned photoresist layer so as to cause the precursors to reflow into rounded shapes;
transferring the rounded shapes into the crystalline layer by etching so as to form the microlenses in the crystalline layer; and
removing the photoresist remaining on the etched crystalline layer.

10. The method according to claim 8 , wherein etching the outer surface comprises randomly roughening the outer surface by etching.

11. The method according to claim 8 , wherein the crystalline layer comprises an epitaxial layer of a semiconductor material.

12. The method according to claim 11 , and comprising forming anode contacts for the VCSELs over the crystalline layer.

13. The method according to claim 8 , wherein the crystalline layer comprises a dielectric material.

Assignees

• Apple Inc

Inventors

• Mackinnon Neil
• Li Weiping
• Fan Xiaofeng

Classifications

• H01S5/005 Primary

  Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping (H01S5/026, H01S5/18388 take precedence) · CPC title

• F21Y2115/30

  Semiconductor lasers · CPC title

• H01S5/18388

  Lenses · CPC title

• H01S5/423

  having a vertical cavity · CPC title

• H01S5/18386

  Details of the emission surface for influencing the near- or far-field, e.g. a grating on the surface · CPC title