# US 11,309,464 B2 · Micro-LED design for chief ray walk-off compensation

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- Number: US 11,309,464 B2
- Document ID: US11309464B2
- Status: Granted
- Kind: B2
- Application number: 16/840,114
- Filed: 2020-04-03
- Published: 2021-04-15
- Granted: 2022-04-19
- Earliest claimed: 2019-10-14
- Assignees: Facebook Technologies, LLC
- Applicants: Facebook Technologies, LLC
- Inventors: Stephan Lutgen; François Gérard Franck Olivier; Vasily Zabelin; William Padraic Henry; Markus Broell; Thomas Lauermann; David Massoubre; Daniel Bryce Thompson; Michael Grundmann
- Web page: https://patentgrep.com/patent/US11309464B2

## CPC

- H10H 20/855: Optical field-shaping means, e.g. lenses
- F21V 5/004: {using microlenses}
- F21V 5/005: {using microprisms}
- G02B 9/10: one + and one - component
- G02B 9/16: all the components being simple
- G02B 19/0028: {refractive and reflective surfaces, e.g. non-imaging catadioptric systems}
- G02B 19/0061: {the light source comprising a LED}
- G02B 27/0172: {characterised by optical features}
- G02B 27/0955: {Lenses (lenses per se G02B3/00)}
- G02B 27/0972: {Prisms (prisms per se G02B5/04)}
- G02F 1/133603: {with LEDs}
- H10H 20/84: Coatings, e.g. passivation layers or antireflective coatings
- H10H 29/10: Integrated devices comprising at least one light-emitting semiconductor component covered by group H10H20/00 (active-matrix LED displays H10H29/30)
- H10W 90/00: Package configurations
- F21Y 2115/10: Light-emitting diodes [LED]
- G02B 2027/0112: {comprising device for genereting colour display}
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- F21V: FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- F21Y: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED

## Abstract

Techniques disclosed herein relate to micro light emitting diodes (micro-LEDs) for a display system. A display system includes an array of micro light emitting diodes (micro-LEDs), an array of output couplers optically coupled to the array of micro-LEDs and configured to extract light emitted by respective micro-LEDs in the array of micro-LEDs, a waveguide display, and display optics configured to couple the light emitted by the array of micro-LEDs and extracted by the array of output couplers into the waveguide display. Each output coupler in the array of output couplers is configured to direct a chief ray of the light emitted by a respective micro-LED in the array of micro-LEDs to a different respective direction.

## Claims

### Claim 1

A device comprising:
a micro light emitting diode (micro-LED) including:
a mesa structure including semiconductor materials and sidewalls that are vertical or inwardly tilted in a light emitting direction; and
a backside reflector on a back surface of the mesa structure; and
a micro-lens on top of the micro-LED and configured to extract light emitted by the micro-LED, wherein:
a lateral size of the micro-lens is equal to or greater than 80% of a lateral size of the mesa structure; and
a distance between a focal point of the micro-lens and a top surface of the mesa structure is between 0.8 and 1.25 times of a thickness of the semiconductor materials in the mesa structure.

### Claim 2 (depends on 1)

The device of claim 1, wherein the micro-lens is offset from the micro-LED by a horizontal displacement that is equal to or greater than zero.

### Claim 3 (depends on 1)

The device of claim 1, further comprising at least one of a second micro-lens, a wedge, a prism, a roughened surface, an antireflective coating, a diffractive optical element, or a photonic crystal.

### Claim 4 (depends on 1)

The device of claim 1, wherein the micro-lens includes a spherical micro-lens, an aspherical micro-lens, or a toroidal micro-lens.

### Claim 5 (depends on 1)

The device of claim 1, wherein the micro-lens includes a semiconductor material, a dielectric material including SiO2, TiO2, SiN, HfO, or AlN, or a polymer.

### Claim 6 (depends on 1)

The device of claim 1, wherein the micro-LED further includes a mesa reflector on the sidewalls of the mesa structure.

### Claim 7 (depends on 1)

The device of claim 1, further comprising:
an array of micro-LEDs including a one-dimensional or two-dimensional array of micro-LEDs; and
an array of micro-lenses optically coupled to the array of micro-LEDs, wherein each micro-lens in the array of micro-lenses is configured to direct a chief ray of light emitted by a corresponding micro-LED in the array of micro-LEDs to a different respective direction.

### Claim 8 (depends on 7)

The device of claim 7, wherein each micro-lens in the array of micro-lenses is characterized by a different respective horizontal displacement from the corresponding micro-LED.

### Claim 9

A device comprising:
a micro light emitting diode (micro-LED) including:
a mesa structure including semiconductor materials and sidewalls that are outwardly tilted in a light emitting direction; and
a backside reflector on a back surface of the mesa structure; and
a micro-lens on top of the micro-LED and configured to extract light emitted by the micro-LED, wherein:
a lateral size of the micro-lens is equal to or greater than 80% of a lateral size of the mesa structure; and
a distance between a focal point of the micro-lens and a top surface of the mesa structure is between 1.2 and 4 times of a thickness of the semiconductor materials in the mesa structure.

### Claim 10 (depends on 9)

The device of claim 9, wherein the micro-LED further comprises a mesa reflector conformally formed on the sidewalls of the mesa structure.

### Claim 11 (depends on 9)

The device of claim 9, wherein the micro-LED is characterized by a half-width half-magnitude light emission angle less than 60°, between 30° and 50°, between 15° and 30°, or less than 15°.

### Claim 12 (depends on 9)

The device of claim 9, wherein the micro-lens is offset from the micro-LED by a horizontal displacement that is equal to or greater than zero.

### Claim 13 (depends on 9)

The device of claim 9, further comprising at least one of a second micro-lens, a wedge, a prism, a roughened surface, an antireflective coating, a diffractive optical element, or a photonic crystal.

### Claim 14 (depends on 9)

The device of claim 9, wherein the micro-lens includes a semiconductor material, a dielectric material including SiO2, TiO2, SiN, HfO, or AlN, or a polymer.

### Claim 15 (depends on 9)

The device of claim 9, wherein the mesa structure is characterized by a parabolic or conic shape.

### Claim 16 (depends on 15)

The device of claim 15, wherein the mesa structure is characterized by the conic shape and a mesa facet angle between 30° and 40°.

### Claim 17 (depends on 9)

The device of claim 9, further comprising:
an array of micro-LEDs including a one-dimensional or two-dimensional array of micro-LEDs; and
an array of micro-lenses optically coupled to the array of micro-LEDs, wherein each micro-lens in the array of micro-lenses is configured to direct a chief ray of light emitted by a corresponding micro-LED in the array of micro-LEDs to a different respective direction.

### Claim 18 (depends on 17)

The device of claim 17, wherein each micro-lens in the array of micro-lenses is characterized by a different respective horizontal displacement from the corresponding micro-LED.