# US 2019/0171016 A1 · Compact optical engine and method of manufacturing same

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- Number: US 2019/0171016 A1
- Document ID: US20190171016A1
- Status: Published application
- Kind: A1
- Application number: 16/201,664
- Filed: 2018-11-27
- Published: 2019-06-06
- Earliest claimed: 2017-11-27
- Assignees: North Inc.
- Applicants: North Inc.
- Inventors: Jörg Pierer; Rony Jose James; Stefan Mohrdiek; Douglas R. Dykaar; Martin Joseph Kiik; Syed Moez Haque
- Web page: https://patentgrep.com/patent/US20190171016A1

## CPC

- G02B 27/0176: {characterised by mechanical features}
- G02B 19/0014: {at least one surface having optical power}
- G02B 19/0052: {the light source comprising a laser diode (coupling into light guides using intermediate optical elements G02B6/4204; semiconductor lasers having optical devices external to the laser cavity H01S5/005)}
- G02B 19/009: {for use with infrared radiation}
- G02B 27/0172: {characterised by optical features}
- G02B 27/0911: {Anamorphotic systems}
- G02B 27/0916: {Adapting the beam shape of a semiconductor light source such as a laser diode or an LED, e.g. for efficiently coupling into optical fibers (coupling into light guides using intermediate optical elements G02B6/4204; details of lighting devices in general F21V)}
- G02B 27/102: {for generating a colour image from monochromatic image signal sources}
- G02B 27/1086: {operating by diffraction only}
- 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}
- H01S 5/02224: the gas comprising oxygen, e.g. for avoiding contamination of the light emitting facets
- H01S 5/02253: using lenses
- H01S 5/02255: using beam deflecting elements
- H01S 5/02257: using windows, e.g. specially adapted for back-reflecting light to a detector inside the housing
- H01S 5/0237: by soldering
- H01S 5/4093: {Red, green and blue [RGB] generated directly by laser action or by a combination of laser action with nonlinear frequency conversion}
- G02B 26/101: {with both horizontal and vertical deflecting means, e.g. raster or XY scanners (colour television using laser beams scanning a display screen H04N9/3129)}
- G02B 2027/015: {involving arrangement aiming to get less bulky devices}
- G02B 2027/0174: {holographic}
- G02B 2027/0178: {Eyeglass type (eyeglass details G02C)}
- H01S 5/0071: {for beam steering, e.g. using a mirror outside the cavity to change the beam direction}
- H01S 5/02216: Butterfly-type, i.e. with electrode pins extending horizontally from the housings
- H01S 5/02325: Mechanically integrated components on mount members or optical micro-benches
- H01S 5/042: Electrical excitation {; Circuits therefor (monolithically integrated laser drive components H01S5/0261)}
- H01S 5/4012: {Beam combining, e.g. by the use of fibres, gratings, polarisers, prisms}
- H01S 5/4087: {emitting more than one wavelength}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL

## 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. Such optical engines may have various 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.

## Claims

### Claim 1

A method of manufacturing an optical engine, the method comprising:
bonding a plurality of chip submounts to a base substrate, each of the chip submounts including a laser diode bonded thereto; and
bonding a cap comprising at least one wall and at least one optical window to the base substrate, the at least one wall, the at least one optical window, and at least a portion of the base substrate together delimit an interior volume sized and dimensioned to receive at least the plurality of chip submounts and laser diodes bonded to the plurality of chip submounts, the bonding of the cap to the base substrate providing 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 light emitted from the laser diodes to exit the interior volume.

### Claim 2 (depends on 1)

The method of claim 1, further comprising:
bonding at least one of the laser diodes to a corresponding one of the plurality of chip submounts.

### Claim 3 (depends on 2)

The method of claim 2 wherein bonding at least one of the laser diodes to a corresponding one of the plurality of chip submounts comprises bonding at least one of the laser diodes to a corresponding one of the plurality of chip submounts using a eutectic gold tin (AuSn) solder process.

### Claim 4 (depends on 1)

The method of claim 1, further comprising:
positioning a plurality of collimation lenses to be adjacent the at least one optical window, each of the plurality of collimation lenses positioned and oriented to receive light from a corresponding one of the laser diodes through the at least one optical window; and
actively aligning each of the plurality of collimation lenses.

### Claim 5 (depends on 4)

The method of claim 4, further comprising:
subsequent to actively aligning each of the plurality of collimation lenses, bonding each of the collimation lenses to the at least one optical window.

### Claim 6 (depends on 4)

The method of claim 4 wherein actively aligning each of the plurality of collimation lenses comprises positioning each of the collimation lenses to optimize spot and pointing for each of the respective laser diodes.

### Claim 7 (depends on 4)

The method of claim 4, further comprising:
positioning a beam combiner to combine light beams received from each of the collimation lenses into a single aggregate beam.

### Claim 8 (depends on 1)

The method of claim 1, further comprising:
prior to bonding the cap to the base substrate, bonding an optical director element to the base substrate proximate the laser diodes, the optical director element positioned and oriented to direct laser light from the laser diodes toward the optical window of the cap.

### Claim 9 (depends on 8)

The method of claim 8 wherein bonding an optical director element comprises bonding one of a mirror or prism to the base substrate proximate the laser diodes.

### Claim 10 (depends on 8)

The method of claim 8 wherein bonding an optical director element comprises bonding an optical director element to a base substrate using at least one of a reflow oven process, thermosonic bonding, thermocompression bonding, transient liquid phase (TLP) bonding, or laser soldering.

### Claim 11 (depends on 1)

The method of claim 1, further comprising:
providing a coupling between at least one laser diode driver circuit and the laser diodes, in operation the at least one laser diode driver circuit selectively drives current to the laser diodes.

### Claim 12 (depends on 1)

The method of claim 1, further comprising:
bonding at least one laser diode driver circuit to the base substrate; and
providing a coupling between the at least one laser diode driver circuit and the laser diodes, in operation the at least one laser diode driver circuit selectively drives current to the laser diodes.

### Claim 13 (depends on 12)

The method of claim 12 wherein bonding the at least one laser diode driver circuit to the base substrate comprises bonding the at least one laser diode driver circuit to a first surface of the base substrate, and bonding the cap to the base substrate comprises bonding the cap to a second surface of the base substrate, the second surface of the base substrate opposite the first surface of the base substrate.

### Claim 14 (depends on 12)

The method of claim 12 wherein bonding the at least one laser diode driver circuit to the base substrate comprises bonding the at least one laser diode driver circuit to a first surface of the base substrate, and bonding the cap to the base substrate comprises bonding the cap to the first surface of the base substrate.

### Claim 15 (depends on 1)

The method of claim 1, further comprising:
providing the base substrate, wherein the base substrate is formed from one of low temperature co-fired ceramic aluminum nitride (AlN), Kovar® or alumina.

### Claim 16 (depends on 1)

The method of claim 1 wherein bonding a plurality of chip submounts to a base substrate comprises step-soldering a plurality of chip submounts to a base substrate.

### Claim 17 (depends on 1)

The method of claim 1 wherein bonding a plurality of chip submounts to a base substrate comprises bonding a plurality of chip submounts to a base substrate using at least one of a reflow oven process, thermosonic bonding, thermocompression bonding, transient liquid phase (TLP) bonding, or laser soldering.

### Claim 18 (depends on 1)

The method of claim 1 wherein bonding a cap to the base substrate comprises bonding a cap to the base substrate using at least one of a seam welding process, a laser assisted soldering process, or a diffusion bonding process.

### Claim 19 (depends on 1)

The method of claim 1, further comprising:
prior to bonding the cap to the base substrate, flooding the interior volume with an oxygen rich atmosphere.

### Claim 20 (depends on 1)

The method of claim 1 wherein bonding a plurality of chip submounts to a base substrate comprises bonding a chip submount that has a red laser diode bonded thereto, bonding a chip submount that has a green laser diode bonded thereto, bonding a chip submount that has a blue laser diode bonded thereto, and bonding a chip submount that has an infrared laser diode bonded thereto.

### Claim 21 (depends on 1)

The method of claim 1 wherein bonding a plurality of chip submounts to a base substrate comprises soldering a plurality of chip submounts to a base substrate using a reactive multi-layer foil material preform.