# US 2021/0240018 A1 · Display system with variable power reflector

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2021/0240018 A1
- Document ID: US20210240018A1
- Status: Published application
- Kind: A1
- Application number: 17/175,566
- Filed: 2021-02-12
- Published: 2021-08-05
- Earliest claimed: 2017-02-23
- Assignees: Magic Leap, Inc.
- Applicants: Magic Leap, Inc.
- Inventors: Brian T. Schowengerdt; John Graham Macnamara; Chulwoo Oh
- Web page: https://patentgrep.com/patent/US20210240018A1

## CPC

- G02B 5/20: Filters (polarising elements G02B5/30)
- G02F 1/137: characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
- G02B 5/30: Polarising elements (light-modulating devices with active elements G02F1/00)
- G02B 6/0026: {Wavelength selective element, sheet or layer, e.g. filter or grating}
- G02B 6/0055: {Reflecting element, sheet or layer}
- G02B 6/0056: {for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements}
- G02B 6/0076: {Stacked arrangements of multiple light guides of the same or different cross-sectional area}
- G02B 6/0088: {of the light guide or other optical sheets in the package}
- G02B 26/0825: {the reflecting element being a flexible sheet or membrane, e.g. for varying the focus (flexible mirrors for cosmetic use A45D42/24)}
- G02B 27/0172: {characterised by optical features}
- G02F 1/13306: {Circuit arrangements or driving methods for the control of single liquid crystal cells (G02F1/132, G02F1/133382 take precedence)}
- G02F 1/13718: {based on a change of the texture state of a cholesteric liquid crystal}
- G02F 1/29: for the control of the position or the direction of light beams, i.e. deflection
- G02F 2203/07: Polarisation dependent
- 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

## Abstract

A wearable augmented reality head-mounted display system can be configured to pass light from the world forward a wearer wearing the head-mounted system into an eye of the wearer. The head-mounted display system can include an optical display that is configured to output light to form an image. The system may include one or more waveguides that are disposed to receiving the light from the display. A variable power reflector can be disposed on the forward side of the one or more waveguides. The reflector can be configured to have an optical power that is adjustable upon application of an electrical signal.

## Claims

### Claim at position 1

1-36. (canceled)

### Claim 37

A display device, comprising:
a waveguide configured to propagate visible light under total internal reflection in a direction parallel to a major surface of the waveguide and to outcouple the visible light in a direction normal to the major surface; and
a deformable mirror configured to reflect visible light having a first polarization, wherein the deformable mirror comprises at least one of a notch reflector or one or more cholesteric liquid crystal (CLC) layers, wherein each of the CLC layers comprises a plurality of chiral structures, wherein each of the chiral structures comprises a plurality of liquid crystal molecules that extend in a layer depth direction and are successively rotated in a first rotation direction, and wherein arrangements of the liquid crystal molecules of the chiral structures vary periodically in a lateral direction perpendicular to the layer depth direction such that the one or more CLC layers are configured to Bragg-reflect incident light.

### Claim 38 (depends on 37)

The display device of claim 37, wherein the waveguide is configured to outcouple the visible light selectively towards the deformable mirror.

### Claim 39 (depends on 37)

The display device of claim 37, wherein different ones of the one or more CLC layers are configured to reflect visible light having a wavelength in a wavelength range corresponding to different ones of red, green or blue light, while being configured to transmit light having a wavelength outside the wavelength range.

### Claim 40 (depends on 37)

The display device of claim 37, wherein each of the chiral structures of the CLC layers comprises a plurality of liquid crystal molecules that extend in a layer depth direction by at least a helical pitch, and wherein different ones of the one or more CLC layers have different helical pitches.

### Claim 41 (depends on 37)

The display device of claim 37, wherein different ones of the one or more CLC layers have substantially the same optical power.

### Claim 42 (depends on 37)

The display device of claim 37, wherein the display device comprises a plurality of notch reflectors, wherein each of the notch reflectors is configured to reflect visible light having the first polarization, wherein each of the notch reflectors comprises one or more cholesteric liquid crystal (CLC) layers, wherein each of the CLC layers comprises a plurality of chiral structures, wherein each of the chiral structures comprises a plurality of liquid crystal molecules that extend in a layer depth direction and are successively rotated in a first rotation direction, and wherein arrangements of the liquid crystal molecules of the chiral structures vary periodically in a lateral direction perpendicular to the layer depth direction such that the one or more CLC layers are configured to Bragg-reflect incident light.

### Claim 43 (depends on 42)

The display device of claim 42, wherein different ones of the plurality of notch reflectors have different optical powers.

### Claim 44 (depends on 42)

The display device of claim 42, further comprising a half-wave plate corresponding to each of the plurality of notch reflectors.

### Claim 45 (depends on 37)

The display device of claim 37, wherein the waveguide comprises a cholesteric liquid crystal diffraction grating configured to outcouple some of the visible light propagating in the waveguide towards the deformable mirror.

### Claim 46 (depends on 37)

The display device of claim 37, wherein the deformable mirror is configured to redirect the visible light directed by the waveguide toward the deformable mirror back toward the waveguide.

### Claim 47 (depends on 46)

The display device of claim 46, wherein the deformable mirror comprises a forward side and a rearward side, the rearward side positioned closer to the waveguide than the forward side, and wherein the deformable mirror is configured to allow at least some light transmitted from an external light source positioned on the forward side of the deformable mirror to pass through the deformable mirror.

### Claim 48 (depends on 37)

The display device of claim 37, further comprising a frame configured to dispose the waveguide forward of an eye of a wearer such that the waveguide comprises a forward side and a rearward side, the rearward side positioned closer to the eye than the forward side, wherein the deformable mirror is disposed on the forward side and is configured to redirect light from the waveguide toward the eye of the wearer.

### Claim 49 (depends on 48)

The display device of claim 48, further comprising a light projector configured to output the visible light toward the waveguide, wherein the deformable mirror is configured to reflect the visible light having the first polarization while transmitting light from an external light source located forward of the deformable mirror.

### Claim 50 (depends on 49)

The display device of claim 49, further comprising one or more in-coupling elements disposed with respect to the waveguide to redirect the visible light from the light projector into the waveguide.

### Claim 51 (depends on 48)

The display device of claim 48, further comprising one or more out-coupling elements disposed with respect to the waveguide to selectively extract some of the visible light propagating in the waveguide and direct the extracted visible light toward the deformable mirror, the light being redirected from the deformable mirror back through the waveguide and into the eye of the wearer.

### Claim 52 (depends on 51)

The display device of claim 51, wherein the one or more out-coupling elements comprise a cholesteric liquid crystal diffraction grating.