Optical device with one-way mirror

Patent metadata

Field	Value
Publication number	US-2021302636-A1
Application number	US-202117211457-A
Country	US
Kind code	A1
Filing date	Mar 24, 2021
Priority date	Mar 25, 2020
Publication date	Sep 30, 2021
Grant date	—

Abstract

In some implementations, an optical device includes a one-way mirror formed by a polarization selective mirror and an absorptive polarizer. The absorptive polarizer has a transmission axis aligned with the transmission axis of the reflective polarizer. The one-way mirror may be provided on the world side of a head-mounted display system. Advantageously, the one-way mirror may reflect light from the world, which provides privacy and may improve the cosmetics of the display. In some implementations, the one-way mirror may include one or more of a depolarizer and a pair of opposing waveplates to improve alignment tolerances and reduce reflections to a viewer. In some implementations, the one-way mirror may form a compact integrated structure with a dimmer for reducing light transmitted to the viewer from the world.

First claim

1 . An optical device comprising:
a one-way mirror comprising:
a depolarizer;
a polarization selective mirror oriented to receive light from the depolarizer and having a transmission axis; and
an absorptive polarizer oriented to receive light from the polarization selective mirror and having a transmission axis aligned with the transmission axes of the polarization selective mirror,
wherein the polarization selective mirror is disposed between the depolarizer and the absorptive polarizer.

2 . The optical device of claim 1 , wherein the depolarizer comprises a quarter waveplate.

3 - 47 . (canceled)

48 . The optical device of claim 1 , wherein the depolarizer comprises a super retarder.

49 . The optical device of claim 1 , wherein the depolarizer is configured to output circularly polarized light from received polarized light.

50 . The optical device of claim 1 , wherein the polarization selective mirror comprises a reflective polarizer.

51 . The optical device of claim 1 , wherein the polarization selective mirror and the absorptive polarizer are spaced apart, and further comprising one or more retarders between the polarization selective mirror and the absorptive polarizer.

52 . The optical device of claim 51 , wherein one or more retarders comprises two spaced-apart quarter wave plates.

53 . The optical device of claim 1 , wherein the reflective polarizer comprises a wire-grid polarizer.

54 . The optical device of claim 53 , wherein the wire-grid polarizer comprises a nano-scale wire pattern with repeating parallel wires.

55 . The optical device of claim 54 , wherein the wires of the wire pattern are each elongated parallel to the transmission axis of the polarization selective mirror.

56 . The optical device of claim 1 , wherein the reflective polarizer comprises a multi-layer polarizer.

57 . The optical device of claim 56 , wherein the multi-layer polarizer is configured to reflect incident light of a pre-determined wavelength.

58 . The optical device of claim 56 , wherein the multi-layer polarizer comprises a plurality of polymer films.

59 . The optical device of claim 56 , wherein the multi-layer polarizer reflects 50% or less of incident light with an electric field vector perpendicular to the transmission axis of the multi-layer polarizer.

60 . The optical device of claim 56 , wherein the multi-layer polarizer reflects 30%-40% of incident light with an electric field vector perpendicular to the transmission axis of the multi-layer polarizer.

61 . The optical device of claim 1 , wherein the absorptive polarizer is configured to absorb linearly polarized light.

62 . The optical device of claim 1 , further comprising:
an actively variable dimmer comprising:
an array of liquid crystal elements; and
a polarizer,
wherein the array of liquid crystal elements is between the polarizer and the absorptive polarizer of the one-way mirror.

63 . The optical device of claim 1 , wherein the optical device is a head-mounted display system, wherein the display system comprises:
a head-mounted display, wherein the one-way mirror is disposed on the head-mounted display and opposite a user side of the display.

64 . The optical device of claim 63 , wherein the display comprises an eyepiece comprising a waveguide stack, the waveguide stack comprising:
a plurality of waveguides each configured to output light to a viewer.

65 . The optical device of claim 64 , wherein each waveguide of the plurality of waveguides is configured to output light with a different amount of wavefront divergence than one or more other waveguides of the plurality of waveguides,
wherein different amounts of wavefront divergence correspond to different depth planes.

Assignees

• Magic Leap Inc

Inventors

• Oh Chulwoo
• Komanduri Ravi Kumar
• Kleinman David
• Mathur Vaibhav
• Manly David

Classifications

• G02F2203/12

  spatial light modulator · CPC title

• G02F1/13306

  Circuit arrangements or driving methods for the control of single liquid crystal cells (G02F1/132, G02F1/133382 take precedence) · CPC title

• G02F2203/48

  Variable attenuator · CPC title

• G02B2027/0174

  holographic · CPC title

• G02B2027/0112

  comprising device for genereting colour display · CPC title