POLARIZATION-SENSITIVE PANCAKE OPTICS

Number: 20190243147
Published: 2019-08-08
Filed: 2018-02-07
Assignee: Disney Enterprises, Inc.
Inventors: SMITHWICK; Quinn Yorklun Jen, HASELTINE; Eric C.
CPC: G02B27/0103; G02B5/0294; G02B3/08; G02B5/3025; G02B27/283; G02B5/3083; G02B5/30; G02B27/0172; G02B27/10
Verdict: Medium Hardware
Source: Google Patents · FreePatentsOnline

The keeper's note

Polarization-sensitive pancake optics (AR/VR display hardware).

Abstract

Implementations of augmented reality (AR)/virtual reality (VR) display devices with optical arrangements that are compact and brighter than traditional pancake optics are disclosed herein. One embodiment provides a display device in which the traditional pancake optics' concave 50/50 beam splitter mirror element is replaced with a linearly polarization-selective mirror element, producing four times the brightness of traditional pancake optics while being approximately half as thick as a simple magnifier. In another embodiment, a display device includes both the concave linearly polarization-selective mirror element and a circularly polarization-selective mirror element, producing even brighter output. In a further embodiment, a display device includes a flat (rather than concave) linearly polarization-selective mirror element and one or more additional lens elements that collimate light, which may reduce aberrations and/or thickness. In yet another embodiment, the arrangement of optical elements is “flipped” such that the polarization-selective mirror element is flat and relatively easier to manufacturer.

Background

BACKGROUNDField

The present disclosure generally relates to computer-based entertainment, and more specifically to optical arrangements suitable for augmented reality (AR) and/or virtual reality (VR) display devices.Description of the Related Art

Computer graphics technology has significantly progressed since the first video games were developed. Relatively inexpensive 3D graphics engines can now produce nearly photo-realistic interactive virtual environments. Virtual reality (VR) in particular involves generating images, sounds, etc. that simulate a user's presence in a virtual environment, typically using specialized equipment such as VR headsets. In contrast, augmented reality (AR) involves superimposing computer generated imagery on a user's view of the real-world environment.

VR/AR head-mounted displays, as well as other types of displays such as those of flight simulators, can require a wide field of view and high resolution with a large eyebox. A simple magnifier, such as that shown in FIG. 1, is one approach for making a wide field of view, high-resolution display with a large eyebox. As shown in FIG. 1, a display device 100 with a simple magnifier typically includes a display 110 disposed at a focal plane of a lens element 120 that collimates light emitted by the display 110, making the displayed imagery appear to be “at infinity,” or very far away. The longer the focal length of the lens element 120, the larger the eyebox, making for easier eye ali

Claims

1. A display device, comprising: a display configured to emit light; and an optical arrangement including: a first beam splitter mirror element, the first beam splitter mirror element being linearly polarization-selective and configured to transmit a portion of the emitted light as a first linearly polarized light, a quarter-wave plate element configured to convert the first linearly polarized light into a first circularly polarized light, and a second beam splitter mirror element configured to reflect, toward the quarter-wave plate element, a first portion of the first circularly polarized light, wherein: the quarter-wave plate converts the reflected first portion of the first circularly polarized light into a second linearly polarized light, the first beam splitter mirror element reflects, toward the quarter-wave plate element, the second linearly polarized light with a 180 degree rotation as a third linearly polarized light, the quarter-wave plate element converts the third linearly polarized light into a second circularly polarized light, and the second beam splitter mirror element transmits a portion of the second circularly polarized light. | 20. A display device, comprising: a display configured to emit light; and an optical arrangement including: a circular polarizer element configured to transmit a portion of the emitted light as a first circularly polarized light, a concave first beam splitter mirror element configured to transmit a portion of the first circularly polarized light, a quarter-wave plate element configured to convert the portion of the first circularly polarized light transmitted by the first beam splitter into a first linearly polarized light, and a flat second beam splitter mirror element, the second beam splitter mirror element being linearly polarization-selective and configured to reflect, toward the quarter-wave plate element, the first linearly polarized light, wherein: the reflected first linearly polarized light is converted by the quarter-wave plate into a second circularly polarized light, the first beam splitter mirror element reflects, toward the quarter-wave plate element, the second circularly polarized light with an orthogonal polarization as a third circularly polarized light, the quarter-wave plate element converts the third circularly polarized light into a second linearly polarized light, and the second beam splitter mirror element transmits the second linearly polarized light. | 24. A display device, comprising: a display; a linearly polarization-selective beam splitter mirror element; a quarter-wave plate element; and at least one of a half-silvered beam splitter mirror element and a circularly polarization-selective mirror element.