# US 2020/0402871 A1 · Polymer patterned disk stack manufacturing

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- Number: US 2020/0402871 A1
- Document ID: US20200402871A1
- Status: Published application
- Kind: A1
- Application number: 16/909,760
- Filed: 2020-06-23
- Published: 2020-12-24
- Earliest claimed: 2019-06-24
- Assignees: Magic Leap, Inc.
- Applicants: Magic Leap, Inc.
- Inventors: Ling Li; Chieh Chang; Sharad D. Bhagat; Christophe Peroz; Brian George Hill; Roy Matthew Patterson; Satish Sadam
- Web page: https://patentgrep.com/patent/US20200402871A1

## CPC

- G02B 3/0062: {Stacked lens arrays, i.e. refractive surfaces arranged in at least two planes, without structurally separate optical elements in-between}
- H10W 46/00: Marks applied to devices, e.g. for alignment or identification
- B29C 39/026: {characterised by the shape of the surface}
- B29D 11/0073: {Optical laminates}
- B29D 11/00769: {Producing diffraction gratings}
- B29D 11/00951: {Measuring, controlling or regulating}
- G01B 11/27: for testing the alignment of axes {(means for centering or aligning a light guide within a ferrule G02B6/3834)}
- G02B 27/34: illuminated
- G02B 27/4272: {having plural diffractive elements positioned sequentially along the optical path}
- G02B 27/62: Optical apparatus specially adapted for adjusting optical elements during the assembly of optical systems
- G02B 5/1814: {structurally combined with one or more further optical elements, e.g. lenses, mirrors, prisms or other diffraction gratings (G02B5/189 takes precedence)}
- G02B 6/0016: {Grooves, prisms, gratings, scattering particles or rough surfaces}
- G02B 6/0031: {Reflecting element, sheet or layer}
- G02B 6/34: utilising prism or grating {(G02B6/293 takes precedence)}
- G02B 27/0172: {characterised by optical features}
- H10P 74/27: {Structural arrangements therefor}
- H10W 46/301: {for alignment}
- H10W 46/401: {for identification or tracking}
- H10W 46/607: {Located on parts of packages, e.g. on encapsulations or on package substrates}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00)
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A method of aligning a stencil to an eyepiece wafer includes providing the stencil, positioning the stencil with respect to a first light source, and determining locations of at least two stencil apertures. The method also includes providing the eyepiece wafer. The eyepiece wafer includes at least two eyepiece waveguides, each eyepiece waveguide including an incoupling grating and a corresponding diffraction pattern. The method further includes directing light from one or more second light sources to impinge on each of the corresponding diffraction patterns, imaging light diffracted from each incoupling grating, determining at least two incoupling grating locations, determining offsets between corresponding stencil aperture locations and incoupling grating locations, and aligning the stencil to the eyepiece wafer based on the determined offsets.

## Claims

### Claim 1

A method of aligning a stencil to an eyepiece wafer, the method comprising:
providing the stencil;
positioning the stencil with respect to a first light source;
determining locations of at least two stencil apertures;
providing the eyepiece wafer, wherein the eyepiece wafer includes at least two eyepiece waveguides, each eyepiece waveguide including an incoupling grating and a corresponding diffraction pattern;
directing light from one or more second light sources to impinge on each of the corresponding diffraction patterns;
imaging light diffracted from each incoupling grating;
determining at least two incoupling grating locations;
determining offsets between corresponding stencil aperture locations and incoupling grating locations; and
aligning the stencil to the eyepiece wafer based on the determined offsets.

### Claim 2 (depends on 1)

The method of claim 1 wherein the at least two stencil aperture locations comprise four aperture locations or six aperture locations.

### Claim 3 (depends on 1)

The method of claim 1 wherein determining the at least two stencil aperture locations comprises:
imaging light from the first light source using a first camera after the light from the first light source passes through a first aperture of the at least two stencil apertures; and
imaging light from the first light source using a second camera after the light from the first light source passes through a second aperture of the at least two stencil apertures.

### Claim 4 (depends on 1)

The method of claim 1 wherein determining the at least two stencil aperture locations comprises:
imaging light from the first light source using a camera after the light from the first light source passes through a first aperture of the at least two stencil apertures; and
imaging light from the first light source using the camera after the light from the first light source passes through a second aperture of the at least two stencil apertures.

### Claim 5 (depends on 1)

The method of claim 1 further comprising, after directing light from each of the one or more second light sources to impinge on each of the corresponding diffraction patterns, redirecting at least a portion of the light from each of the one or more second light sources to each of the incoupling gratings via total internal reflection.

### Claim 6 (depends on 1)

The method of claim 1 wherein imaging light diffracted from each incoupling grating comprises:
imaging light from a primary light source of the one or more second light sources using a first camera after the light from primary light source diffracts from a first incoupling grating of the incoupling gratings; and
imaging light from a secondary light source of the one or more second light sources using a second camera after the light from the secondary light source through a second incoupling grating of the incoupling gratings.

### Claim 7 (depends on 1)

The method of claim 1 wherein imaging light diffracted from each incoupling grating comprises:
imaging light from a primary light source of the one or more second light sources using a camera after the light from the primary light source diffracts from a first incoupling grating of the incoupling gratings; and
imaging light from a secondary light source of the one or more secondary light sources using the camera after the light from the secondary light source diffracts from a second incoupling grating of the incoupling gratings.

### Claim 8 (depends on 1)

The method of claim 1 wherein aligning the stencil to the eyepiece wafer comprises moving the eyepiece wafer with respect to the stencil to reduce the determined offsets.

### Claim 9 (depends on 8)

The method of claim 8 wherein moving the eyepiece wafer comprises translating and rotating the eyepiece wafer and reducing the determined offsets comprises minimizing the determined offsets.

### Claim 10

A system comprising:
a first chuck operable to support a stencil including a plurality of apertures;
a wafer chuck operable to support and move a wafer including a plurality of incoupling gratings;
a first light source operable to direct light to impinge on a first surface of the stencil;
one or more second light sources operable to direct light to impinge on the wafer;
one or more lens and camera assemblies operable to:
receive light from the first light source passing through the plurality of apertures in the stencil; and
receive light from the one or more second light sources diffracted from the plurality of incoupling gratings in the wafer; and
an alignment system operable to move the wafer with respect to the stencil in order to reduce an offset between aperture locations and incoupling grating locations.

### Claim 11 (depends on 10)

The system of claim 10 wherein the one or more lens and camera assemblies comprises:
a first camera operable to detect an aperture position of a first aperture of the plurality of apertures; and
a second camera operable to detect an aperture position of a second aperture of the plurality of apertures.

### Claim 12 (depends on 10)

The system of claim 10 wherein the one or more lens and camera assemblies comprises a single camera operable to detect an aperture position of a first aperture of the plurality of apertures and an aperture position of a second aperture of the plurality of apertures.

### Claim 13 (depends on 10)

The system of claim 10 wherein the light from the one or more second light sources diffracted from the incoupling gratings in the wafer propagates by total internal reflection prior to being diffracted out of the wafer from the incoupling gratings.

### Claim 14 (depends on 10)

The system of claim 10 wherein moving the wafer with respect to the stencil comprises:
rotating and translating the wafer; and
thereafter, bringing the wafer into contact with the stencil.

### Claim 15 (depends on 10)

The system of claim 10 wherein the first light source and the one or more second light sources are positioned on opposing sides of the wafer.

### Claim 16

An assembly system comprising:
a wafer casting station;
a stencil placement station;
a deposition station;
a stencil separation station;
a first inspection station;
a layer assembly station; and
a second inspection station.

### Claim 17 (depends on 16)

The assembly system of claim 16 wherein the stencil placement station comprises:
a first chuck operable to support a stencil including a plurality of apertures;
a wafer chuck operable to support and move a wafer including a plurality of incoupling gratings;
a first light source operable to direct light to impinge on a first surface of the stencil;
one or more second light sources operable to direct light to impinge on the wafer;
one or more lens and camera assemblies operable to:
receive light from the first light source passing through the plurality of apertures in the stencil; and
receive light from the one or more second light sources diffracted from the plurality of incoupling gratings in the wafer; and
an alignment system operable to move the wafer with respect to the stencil in order to reduce an offset between aperture locations and incoupling grating locations.

### Claim 18 (depends on 17)

The assembly system of claim 17 wherein the one or more lens and camera assemblies comprises:
a first camera operable to detect an aperture position of a first aperture of the plurality of apertures; and
a second camera operable to detect an aperture position of a second aperture of the plurality of apertures.

### Claim 19 (depends on 17)

The assembly system of claim 17 wherein the one or more lens and camera assemblies comprises a single camera operable to detect an aperture position of a first aperture of the plurality of apertures and an aperture position of a second aperture of the plurality of apertures.

### Claim 20 (depends on 17)

The assembly system of claim 17 wherein the light from the one or more second light sources diffracted from the incoupling gratings in the wafer propagates by total internal reflection prior to being diffracted out of the wafer from the incoupling gratings.