Eyebox steering and field of view expansion using beam steering elements

Abstract

An eyewear device includes a light guide having a world-side surface and an eye-side surface, a display oriented to emit light toward the light guide, and a beam-steering element including a first polarization grating positioned along a light path between the display. The first polarization grating diffracts light emitted by the display into orders having different polarizations, and the orders are selectively transmitted into different eyeboxes. The eyewear device also includes a frame that supports the light guide, the display, and the first polarization grating. In some cases, the different polarizations include right circular polarization or left circular polarization, and the beam-steering element includes a polarization-dependent filter that filters right circularly polarized light in a first state and filters left circularly polarized light in a second state.

Description

Background Technology

[0001] Wearable electronic goggles include an optical system that magnifies and delivers virtual images into the user's field of view (FOV). The device also allows the user to see the outside world through lenses or see-through eyepieces. Some wearable electronic goggles incorporate near-eye optics to display content to the user. For example, previous goggle designs included miniature displays ("displays") located in the temples or edge areas of the wearable head frame, much like a pair of traditional glasses. The displays generate images such as computer-generated images (CGI), which are transmitted to the user's FOV via optical elements such as curved waveguides deployed in lenses (or see-through eyepieces) of the wearable head frame. Therefore, wearable electronic goggles can serve as a hardware platform for implementing augmented reality (AR). Different modes of augmented reality include optical see-through augmented reality, video see-through augmented reality, or opaque (VR) modes. Summary of the Invention

[0002] Electronically enhanced goggles (EEGs) have the potential for numerous practical and recreational applications; however, the development and adoption of wearable EEGs have been limited by the quality, cost, size, weight, thickness, field of view, and efficiency of the optical systems used to implement existing goggles. For example, the geometric and physical constraints of conventional designs result in a low field of view (FOV) for the display. Furthermore, the potential user population exhibits a wide range of facial geometries, characterized by the distribution of nose geometry, ear-to-ear distance, and interpupillary distance (i.e., the distance between the centers of the user's pupils). It is impossible for a single wearable EEG to provide an optimal experience for all users while satisfying all the physical and geometric constraints of the wearable device. For instance, if a user's pupil falls within the "eyebox" created by the optical system implemented in the device, the user only sees the entire image displayed by the wearable EEG. However, conventional wearable EEGs produce a relatively small eyebox whose distribution across the entire facial geometry does not cover the pupil position. Therefore, not all users are able to view the image displayed by the wearable EEG.

[0003] One aspect of the proposed solution relates to a goggle device comprising: a waveguide having a world-side surface and an eye-side surface; a display oriented to emit light toward the waveguide; and a beam steering element comprising at least one of a first polarizing grating and a polarization-dependent filter positioned along an optical path between the display and the waveguide, the beam steering element being configured to operate in at least two different states, wherein in a first state, light enters directly into a first eye box, and in a second state, light enters directly into a second eye box, the second eye box having a different size than the first eye box, specifically a different volume. In one embodiment, the first polarizing grating is configured to diffract the light emitted from the display into different polarization orders and selectively deliver these orders to different eye boxes, the eye box being defined as a three-dimensional volume within the space of the pupil of the user's eye in the goggle device. Generally, an "eye box" is generated from the emission cone of light emitted from an optical waveguide in an electronic goggle device. Therefore, goggle devices and their beam steering elements can be configured to provide emission cones of different geometries and / or sizes. As used herein, the term "eyebox" refers to a three-dimensional (3D) volume in space within which the pupil of the eye is located to satisfy one or more viewing experience criteria. An example of a viewing experience criterion is that a user sees the four edges of a magnified virtual image. In this case, the eyebox is a 3D volume in space within which the user's pupil is located to see the four edges of the magnified virtual image. In some embodiments, the volume and orientation of the eyebox generated by the electronic goggle device are evaluated based on the pupil diameter, the angular range of the emission cone generated by the electronic goggle device, a set of criteria, and thresholds used for the criteria. Using beam steering elements in the goggle device, for example, allows selective operation of the goggle device in at least two different states that generate different eyeboxes. In a first state, light representing an image can directly enter a first eyebox, while in a second state, light can directly enter a second eyebox.

[0004] In one embodiment, a user can (e.g., using a switch, button, or other device on the goggle device) selectively place the goggle device in a first or second state, thereby moving the resulting eye box through a range corresponding to the first and second images. Therefore, the effective size of the eye box can be increased, for example, by implementing a switchable beam steering element. The size of the eye box can be a measurable parameter used to address crowd coverage in AR or VR-based devices. In many cases, the size of the eye box determines how many users can see the displayed image while wearing the goggle device. Using the techniques described herein, goggle devices for AR and VR applications are created with large eye boxes to accommodate the increasing number of people in the general population. The position or orientation of the eye box can therefore be moved from one location to another using a beam steering element. For example, the beam steering element can switch between at least two states and between at least two different eye box volumes, the at least two states corresponding to at least two different steering angles at which light exits from the beam steering element.

[0005] In some embodiments, different polarizations include right circular polarization or left circular polarization.

[0006] In some embodiments, right circular polarization corresponds to the +1 order of the polarization grating, while left circular polarization corresponds to the -1 order of the polarization grating.

[0007] In some embodiments, for right-circularly polarized light, the first polarization grating causes the light to diffract at a positive offset angle, and for left-circularly polarized light, the first polarization grating causes the light to diffract at a negative offset angle.

[0008] In some embodiments, the first polarization grating is a basic achromatic liquid crystal polarization grating.

[0009] Some embodiments of the goggle device include a polarization-dependent filter that filters light received from a first polarization grating, and that the polarization-dependent filter filters right-circularly polarized light in a first state and left-circularly polarized light in a second state.

[0010] Some embodiments of the goggle device include a second polarization grating located near the eye-side surface of the light guide, the second polarization grating being configured to selectively direct light emitted from the display into different fields of view (FOV).

[0011] In some embodiments, a second polarization grating is configured to time-multiplex content representing different FOVs to present a larger effective FOV as perceived by a user wearing goggles.

[0012] In some embodiments, the second polarization grating includes a switchable polarization grating that switches between polarizations to time-multiplex content representing different FOVs.

[0013] Another aspect of the proposed solution relates to a goggle device comprising: a waveguide having a world-side surface and an eye-side surface; a display oriented to emit light toward the waveguide; a beam steering element including a polarizing grating positioned along the optical path between the eye-side of the waveguide and the eye of the user of the goggle device, for example, near the eye-side surface of the waveguide, the polarizing grating being configured to selectively direct the light emitted by the display into different fields of view (FOVs); and a frame supporting the waveguide, the display, and the polarizing grating. In some embodiments, as discussed herein, additional beam steering elements may be included that allow the goggle to switch between multiple states to provide different goggle volumes.

[0014] In general, the proposed solution specifically relates to a goggle device comprising: a waveguide having a world-side surface and an eye-side surface; a display oriented to emit light toward the waveguide; at least one beam steering element; and a frame supporting the waveguide, the display, and the at least one beam steering element, wherein the beam steering element is configured to (a) diffract the light emitted by the display into different orders of polarization and selectively deliver the orders to different eye boxes and / or (b) selectively deliver the light emitted by the display to different fields of view (FOVs).

[0015] The embodiments of the proposed goggle device can be configured to implement embodiments of the proposed method. Therefore, the features discussed herein in conjunction with embodiments of the proposed goggle device are also applicable to corresponding embodiments of the proposed method, and vice versa.

[0016] In some embodiments, a method is disclosed comprising emitting light from a display toward a first polarizing grating in a goggle device, the goggle device including a light guide having a world-side surface and an eye-side surface, such that light received from the first polarizing grating is diffracted into orders having different polarizations, and selectively transmitting one of the diffraction orders via the first polarizing grating through the eye-side surface of the light guide to one of a plurality of eye cases.

[0017] In some embodiments, selectively transmitting light emitted by the display to one of a plurality of eyeboxes includes generating orders with right circular polarization and left circular polarization.

[0018] In some embodiments, right circular polarization corresponds to the +1 order of the polarization grating, while left circular polarization corresponds to the -1 order of the polarization grating.

[0019] In some embodiments, causing the light emitted by the display to diffract includes: for right-circularly polarized light, causing the light to diffract at a positive offset angle, and for left-circularly polarized light, causing the light to diffract at a negative offset angle.

[0020] In some embodiments, the first polarization grating is a basic achromatic liquid crystal polarization grating.

[0021] In some embodiments, selectively transmitting one diffraction order includes filtering right-circularly polarized light in a first state and left-circularly polarized light in a second state at a polarization-dependent filter.

[0022] Some embodiments of the method include selectively directing light emitted by the display into different fields of view (FOVs) at a second polarization grating located near the eye-side surface of the light guide.

[0023] In some embodiments, selectively transmitting light includes time-multiplexed content representing different FOVs to present a larger effective FOV as perceived by a user wearing goggles.

[0024] In some embodiments, time multiplexing of content includes switching between circular polarizations associated with different FOVs.

[0025] In some embodiments, a goggle device is disclosed, the goggle device comprising: a light guide having a world-side surface and an eye-side surface; a display oriented to emit light toward the light guide; a polarizing grating positioned near the eye-side surface of the light guide, the polarizing grating being configured to selectively transmit the light emitted by the display into different fields of view (FOV); and a frame supporting the light guide, the display, and the polarizing grating.

[0026] In some embodiments, the beam steering element is configured to time-multiplex content representing different FOVs to present a larger effective FOV as perceived by a user wearing goggles.

[0027] In some embodiments, the beam steering element includes a switchable polarization grating that switches between polarizations to time-multiplex content representing different FOVs.

[0028] In some embodiments, a method is provided that includes emitting light from a display toward a first polarizing grating in a goggle device, the goggle device including a waveguide having a world-side surface and an eye-side surface. The method also includes selectively directing the light emitted from the display to different fields of view (FOVs) via the first polarizing grating.

[0029] In some embodiments, selectively transmitting the light emitted by the display includes time-multiplexed content representing different FOVs to present a larger effective FOV as perceived by a user wearing a goggle device.

[0030] In some embodiments, selectively transmitting light emitted by the display includes switching between polarizations to time-multiplex content representing different FOVs using a switchable polarization grating. Attached Figure Description

[0031] This disclosure is better understood by referring to the accompanying drawings, and many of its features and advantages will be apparent to those skilled in the art. The same reference numerals are used in different drawings to denote similar or identical items.

[0032] Figure 1 It is a scatter plot of head width distribution and interpupillary distance (IPD) distribution.

[0033] Figure 2 Two comparisons of eye boxes generated by different emission cones for light emitted from the optical light guide in the electronic goggle device are shown.

[0034] Figure 3 This is a block diagram of the design of an electronic goggle device according to some embodiments, which provides an extended eye box area at the nominal exit pupil distance plane.

[0035] Figure 4 A perspective view of an electronic goggle device according to some embodiments is shown, the electronic goggle device having a beam steering element and a display for each user's eye.

[0036] Figure 5 The diagram illustrates the relationship between [various embodiments] and [other embodiments]. Figure 4 A front view of the edge frame portion of an alternative embodiment of a goggle device similar to the goggle device.

[0037] Figure 6 This is an illustration of an optical system that uses a beam steering element to generate an enhanced eyebox according to some embodiments.

[0038] Figure 7 This is an illustration of an achromatic polarization grating according to some embodiments.

[0039] Figure 8 This is a block diagram of a beam steering element operating in a first state and a second state according to some embodiments.

[0040] Figure 9 This is an illustration of an optical system that implements selective beam steering to generate an extended eyebox according to some embodiments.

[0041] Figure 10 This is an illustration of an optical system that uses beam steering elements to generate an extended field of view (FOV) according to some embodiments. Detailed Implementation

[0042] Figures 1 to 10 An optical imaging system is disclosed, implemented in a wearable electronic goggle device, to generate eye boxes of different sizes, particularly eye boxes of different volumes, by deploying a first beam steering element along the optical path between a display that generates an image and an optical guide that directs the image to the user's eyes when the user is wearing the device. This allows for the generation, for example, of larger (or adjustable) eye boxes. Some embodiments of the first beam steering element include a switchable polarization grating that shifts the eye box by different offsets according to the order of the diffracted light that generates the eye box. For example, the polarization grating generates orders of diffracted light, and each order has an associated circular chirality. For right-circularly polarized light, the polarization grating causes the light to diffract at a positive offset angle, and for left-circularly polarized light, the polarization grating causes the light to diffract at a negative offset angle. Therefore, the position of the eye box can be switched by switching between right-circular polarization and left-circular polarization, corresponding to the +1 and -1 orders of the polarization grating. Some embodiments use a switchable polarization-dependent filter to switch between right and left circular polarization. In some embodiments, the optical imaging system generates a larger field of view (FOV) by deploying a second beam steering element near the output region of a curved optical guide. The second beam steering element may include a switchable polarization grating that (e.g., by interleaving frames representing different FOVs) switches between polarizations to time-multiplex the content representing different portions of the FOV to present a larger effective FOV as perceived by the user. Some embodiments of wearable electronic goggles devices include a first beam steering element, a second beam steering element, or both the first and second beam steering elements.

[0043] Figure 1 This is a scatter plot 100 comparing the ear tip distribution with the interpupillary distance (IPD) distribution. The vertical axis of scatter plot 100 indicates the width between an individual's ear tips (in millimeters), and the horizontal axis represents the individual's IPD (in millimeters). Each point in scatter plot 100 represents a measurement of both the width and IPD of an individual. The number of individuals with measurements for each width is projected onto distribution 105, and the number of individuals with measurements for each IPD is projected onto distribution 110. Distributions 105 and 110 are characterized by the mean (μ) and standard deviation (σ). For example, distribution 110 of IPD is characterized by:

[0044] μ IPD =62mm

[0045] σ IPD=3.9mm

[0046] The characteristics of width distribution 105 are:

[0047] μ EtE =145.6mm

[0048] σ EtE =7.5mm

[0049] Where EtE represents the width from ear to ear.

[0050] Figure 2 Two comparisons, 200 and 201, are shown of eyeboxes 210 and 215 generated using different emission cones for light emitted from the optical light guide in the electronic goggle device. As used herein, the term "eyebox" refers to a three-dimensional (3D) volume in space within which the pupil of the eye is located to meet one or more viewing experience criteria. An example of a viewing experience criterion is that a user can see the four edges of a magnified virtual image. In this case, the eyebox is a 3D volume in space within which the user's pupil is located to see the four edges of the magnified virtual image. In some embodiments, the volume and orientation of the eyebox generated by the electronic goggle device are evaluated based on the pupil diameter, the angular range of the emission cone generated by the electronic goggle device, a set of criteria, and thresholds used for the criteria.

[0051] Used in a horizontal dimension with 50 ° Full width / half maximum (FWHM) and having 30 in the vertical dimension ° The eyebox 210 is generated using an FWHM firing cone. The eyebox 210 has a dimension of 8.2 mm in the x-direction and 4.8 mm in the y-direction. A 30mm diameter is used in the horizontal dimension. ° FWHM, with a vertical dimension of 50 ° The eyebox 215 is generated using an FWHM (Free-Wide Meter) emitter cone. The eyebox 215 has a dimension of 6.7 mm in the x-direction and 4.8 mm in the y-direction. Therefore, the additional 20℉ WHM improvement in the horizontal dimensions increases the size of the eyebox 210 by 1.5 mm relative to the eyebox 215. In the illustrated embodiment, the thickness of the optical system limits the size of the eyeboxes 210 and 215 along the y-direction.

[0052] Figure 3This is a block diagram of a design 300 for an electronic goggle device providing an extended eye box according to some embodiments. Design 300 includes: an optical system 305 implemented using a display to generate an image; a beam steering element for selectively modifying the direction of light representing the image; and an optical guide for directing the light representing the image toward the user's eyes, as discussed herein. In the illustrated embodiment, the optical system 305 selectively operates in one of two states that generate different eye boxes. In a first state, the optical system 305 introduces light representing the image into a first eye box 310, while in a second state, the optical system 305 introduces light into a second eye box 315. Therefore, the effective eye box generated by the optical system 305 is equal to the combination of the first eye box 310 and the second eye box 315. The optical system 305 generates 50 ° The emission cone is 30℉WHM, and the directional angles of the eye boxes 310 and 315 are respectively... Some embodiments of the optical system 305 operate in more than two states that generate two or more different (possibly overlapping) eyeboxes. The optical system 305 can also generate different FWHM emission cones or steering angles.

[0053] Figure 4 A perspective view of an electronic goggle device 400 having a beam-directing element 401 for each user's eye and a display 405 according to some embodiments is shown. As discussed herein, in some embodiments, the beam-directing element 401 includes a polarization-dependent grating and a switchable polarization-dependent filter. The device 400 includes at least a frame 410, a pair of light guides 402, and a beam-directing element 401 and a display 405 for each user's eye. The beam-directing element 401, also referred to as a polarization grating lens, alters at least one property of the light passing through it. The device 400 generally illustrates the components and their arrangement in various types of goggle devices for providing AR and VR-based vision. The device 400 provides binocular AR-based vision. For clarity, the user's eyes are not shown in this figure.

[0054] The device 400 has the appearance of ordinary eyeglasses, and the display 405 mounted therein has almost no light leakage. In the illustrated embodiment, the display 405 and the beam steering element 101 are located at corresponding leg positions 120 in the device 400. In some embodiments, the light guide 402 is curved, and in other embodiments, the light guide 402 is substantially planar. A frame 410 holds the light guide 402 between its top side 114 and bottom side 122. The frame 410 and the light guide 402 are shaped like lenses of ordinary eyeglasses. Typically, the light guide 402 is transparent and functions as a lens for viewing. The light guide 402 is positioned in front of the user and directs light 406 from the corresponding display 405 toward the user's eyes.

[0055] For the corresponding display 405, each light guide 402 includes a surface with a dielectric mirror coating, which acts as a combiner, wherein light 406 from the display 405 and light 404 entering from the world side 413 are combined to form a resulting image 417, which is then directed toward the user's eye at the eye side 415 of the device 400. Light 404 from the world side 413 passes through the light guide 402 to reach the eye side 415 of the light guide 402, and the light 404 originates from the visible scene on the world side 413 of the goggle device 400.

[0056] As shown, each display 405 is mounted at the edge 425 of the light guide 402, at the leg position 420 of the corresponding light guide 402, and each display 404 is positioned inside or near the frame 410. The light guide 402 allows ambient light 404 to be combined with display light 406 reflected at the combiner surface, which is not separately labeled in the figure for clarity. The frame 410 includes two arms 411 that extend from the leg positions of the frame 410 on the corresponding sides of the frame 410 toward and beyond the user's ear (not shown).

[0057] In some embodiments, device 400 includes or houses components for receiving image data signals and providing image data signals to display 405. The image data signals are a source input to display lamp 406. For example, an arm 411 includes wireless components for receiving wireless signals including the image data signals. Power is provided by local energy sources such as batteries, solar panels, or other forms of energy native to device 400. In another example, cables (not shown) serve as a mechanism for providing power from an external source to various components including display 405 and its corresponding electronic packages. In addition to having power lines, one or more wires in device 400 deliver image data signals to display 405. In some embodiments, the image data signals originate from a computing device or other display driving data source (not shown).

[0058] The placement of the display 405 on the outer side of the light guide 402 is one example of the placement of the display 405. In other embodiments, the display 405 is located at or within the top of the frame 410. Each light guide 402 includes an eye-side surface 424 and a world-side surface 423. Display light 406 is reflected between these surfaces 423, 424 before reaching the user's eye, and is reflected at least once on each surface 423, 424.

[0059] According to some embodiments, each of the light-guiding surfaces 423, 424 is curved and spherical in at least one dimension (e.g., uniform along a fixed radius relative to the focal point of the respective light guide 402), and each of these surfaces 423, 424 has characteristic dimensions (e.g., spherical dimensions, radius, set of curvature parameters) that are similar or approximately the same size as each other to implement zero optical power (diopter) optical permeability. The eye-side surface and the world-side surface can also be designed to integrate prescription correction as part of the light guide.

[0060] For the purposes of description, world-side surface 423 is the first surface, and eye-side surface 424 is the second surface. Each of surfaces 423 and 424 is provided by the same or different physical components in device 400. According to some embodiments, surface 425 of light guide 402 adjacent to display 405 and beam steering element 401 is curved or free-form to correct, if any, astigmatism associated with display 405 and the light 406 emitted therefrom due to the specific arrangement of components of device 400. Surface 425 of light guide 402 adjacent to display 405 is the third surface of device 400 and is curved in one or two dimensions relative to the resulting image 417 at eye side 415 of device 400.

[0061] Another (fourth) surface of the light guide 402, such as the surface at the combiner 419, provides the final reflection of light 406 from the display 405 toward the user's eye, and in at least some embodiments, this fourth surface of the light guide 402 is also curved and bent in a freeform shape. This final surface is equivalently referred to herein as combiner 419 or combiner surface. The image 417 reflected from it is referred to as the light field and is provided to the user's eye. In other embodiments of combiner 419, the final reflecting surface of the light guide 402 is a rotationally symmetric aspherical surface, a deformed aspherical surface, a toroidal surface, a Zernike polynomial shaped surface, a radial basis function shaped surface, an xy polynomial shaped surface, or a non-uniform rational b-spline shaped surface.

[0062] During operation, when the beam steering element 401 changes from a first state to a second state, image 417 moves from a first position to a second position, as shown in the second image 418. Although the movement between the first image 417 and the second image 408 is essentially... Figure 1In the vertical direction, however, in other embodiments, the shift is vertical or a combination of vertical and horizontal. In some embodiments, the position of the first image 417 and its position on the surface of the combiner 419 overlaps with the position of the second image 418, but for clarity, it is shown as a separate and distinct position. Between the first and second states of the beam steering element 401, when the beam steering element 401 is off, a position (not shown) of the image from the display 405 is projected and provided to the eye located between the first image 417 and the second image 418, as shown in one or more other figures.

[0063] In some embodiments, at least some of the components of the light guide 402 of the device 400 operate as optical amplifiers for light 406 emitted from the display 405 due to their arrangement relative to each other and their composition and shape. The techniques described herein are applicable to all types of see-through devices, such as eyeglasses, helmets, head-mounted display (HMD) devices, and windproof shields, and even though only goggle devices such as goggle device 400 are described and shown, the techniques described herein enable the optical merging of computer-generated and real-world scenes to form a combined view.

[0064] The goggle device 400 is selectively placed in a first state or a second state (e.g., using a switch, button, or... for clarity). Figure 1 (Other devices not shown) move the eye box through the range corresponding to the first image 417 and the second image 418. Thus, the effective size of the eye box is increased by implementing a switchable beam steering element 401. The size of the eye box is a measurable parameter used to address crowd coverage in AR or VR-based devices. In many cases, the size of the eye box determines how many users can see the displayed image when wearing the HMD goggle device 400. Using the techniques described herein, goggle devices for AR and VR applications are created with large eye boxes to accommodate the increasing number of people in the general population. The position or orientation of the eye box containing images 417, 418 can be moved from one location to another using the beam steering element 401. Typically, the size of the eye box is a factor of several variables and parameters associated with a particular device, including: the resolution of the display 405 and its light-emitting elements, the color uniformity of the light-emitting elements, field curvature, distortion, and pupil movement.

[0065] Figure 5 Similar to some embodiments are shown. Figure 4A front view of the edge frame portion 510 of an alternative embodiment of the goggle device 500. For clarity, the arms of the device 500 are not shown. The dimensions of the device 500 are based on a pupil diameter 527 of approximately 4 mm positioned relative to the pupil center 526. The pupil diameter 527 is also referred to as the pupil size. Each of the light guides 502 for the left and right eyes (not shown) is based on a frame horizontal box distance 524 of approximately 53 mm—such as between 50 mm and 60 mm—and a frame vertical box distance 531 of approximately 44 mm—such as between 40 mm and 50 mm. The light guides 502 are separated by a bridge length 525 of approximately 17.5 mm. When the user wears the goggle device 500, the bridge length 525 is typically centered at a middle position 530. The fitting height 532 is the distance from the bottom side 522 to the top edge 526 of the light guide 502, and the fitting height is approximately 23 mm from the bottom side 522 to the pupil center 526. The edge frame portion 510 is based on an interpupillary distance (IPD) 534 in the range of approximately 60 mm to 65 mm, such as an IPD 534 based on 62 mm, and has a standard deviation of approximately 3.9 mm. Devices 400, 500 and their components are sized to accommodate a user with an IPD 534 of 62 mm and the two standard deviations in this measurement. Arms for devices 400, 500—such as arm 411 of device 400—are sized and positioned to accommodate ear tips in the range of approximately 140 mm to 150 mm—such as 145.6 mm, and have a standard deviation of approximately 7.5 mm and two standard deviations of 15 mm.

[0066] Regarding the example dimensions of the goggle device 500, the thickness of the light guide 502 in some embodiments is up to about 5 mm, and preferably up to about 4 mm or less. Some optical elements, including the display 505, occupy about 3.5 mm of space hidden in the edge frame portion 510 of the device 500. The top of the edge frame portion 510 has an edge thickness 233 of up to 5 mm, and some embodiments have an edge thickness 233 of 3.5 mm or less, and accommodate various components including optical and electronic components other than the light guide 502.

[0067] To support the electronic components including display 505 and PG 201, electronic cable 212 is shown, and electronic cable 212 will be coupled to one or more goggle arms, a portion of the edge frame portion 510, or a combination thereof. That is, as Figure 1One or more of the goggle arms 111 shown house cables 212 with two or more wires for powering various components, including the display 405 and its supporting electronic package, and for providing image data signals from a computing device or other display driving data source (not shown), to the display 405. In other embodiments, the edge frame portion 510 or one or more arms include or house components for receiving signals and wirelessly providing signals to the display 405. In some embodiments, power is provided by a battery or other form of energy, either local to the device 500 or from a source external to the device 500.

[0068] In the illustrated embodiment, the display 505 is positioned inside the edge thickness 533 at the top of the edge frame portion 510 to provide an image with an aspect ratio of approximately 3:1. The corresponding thickness is approximately 3.5 mm in the headspace within the edge thickness 233 at the top of the edge frame portion 510 to accommodate certain device components. For the display 505 producing images 517, 518 with an aspect ratio of approximately 8:1, the headspace within the edge thickness 533 is up to approximately 4 mm. To reduce the weight of the goggle device 500, although not shown, some embodiments are monocular (having only one light guide 502, one display 505, and one beam steering element 501) in AR or VR-based vision within the device 500, while other embodiments have two displays 505 and two beam steering elements 501 for each of the two light guides.

[0069] Figure 6 The illustration shows an optical system 600 according to some embodiments, which uses a beam steering element 605 to generate an enhanced eyebox. The optical system 600 is shown in [details omitted]. Figure 3 Some embodiments of the optical system 305 shown and Figure 4 and Figure 5 The illustrated goggle devices 400 and 500 are shown in part. Optical system 600 includes a microdisplay 610 that generates an image and provides light represented in the image to an angle filter 615, which provides filtered light to a beam steering element 605. As discussed herein, some embodiments of beam steering element 605 are implemented as liquid crystal polarizing gratings. Optical system 600 also includes a light guide 620 that transmits light received from beam steering element 605 to an exit position located in front of the user's eye 625. In the illustrated embodiment, beam steering element 605 can switch between two states corresponding to two different steering angles, as indicated by the arrows emanating from beam steering element 605, and can switch between two different eye box volumes, as indicated by the arrows emanating from light guide 620 in the direction of the eye 625.

[0070] Figure 7 This is an illustration of an achromatic polarization grating 700 according to some embodiments. The achromatic polarization grating 700 is used to implement... Figure 3 The optical system 305 shown Figure 4 The beam steering element 401 shown Figure 5 The beam steering element 501 shown and Figure 6 Some embodiments of the beam steering element 605 are shown. For example, it can be combined with a switchable polarization filter (for clarity, Figure 7 (Not shown in the image) to implement the achromatic polarization grating 700 to form a switchable polarization grating. Some embodiments of the achromatic polarization grating 700 are formed from polymerizable liquid crystals that use two anti-symmetrical chiral circular polarization gratings with opposite twist to perform chromatic aberration and polarization separation concurrently across the visible light wavelength range with approximately 100% efficiency.

[0071] In operation, the achromatic polarization grating 700 receives unpolarized light 705. The achromatic polarization grating 700 diffracts the unpolarized light 705 to form outgoing beams 710 and 715 with different circular polarizations. Outgoing beam 710 represents the +1 order in the diffraction pattern and is right-circularly polarized. The turning angle of outgoing beam 710 is θ. +1 The outgoing beam 715 represents the -1st order in the diffraction pattern and is left-circularly polarized. The turning angle of the outgoing beam 715 is θ. -1 Use a polarization-dependent filter (for clarity, in...). Figure 7 The emitted light 710 or emitted light 715 is selectively supplied to the optical guide (such as...) in a state where the emitted light is not shown in the image. Figure 6 (See the light guide 620 shown). For example, the polarization-dependent filter can transmit right circularly polarized light 710 in the first state and left circularly polarized light 715 in the second state.

[0072] Figure 8 This is a block diagram of a beam steering element 800 operating in a first state 801 and a second state 802 according to some embodiments. The beam steering element 800 is used to implement... Figure 3 The optical system 305 shown Figure 4 The beam steering element 401 shown Figure 5 The beam steering element 501 shown and Figure 6 Some embodiments of the beam steering element 605 are shown. In the illustrated embodiments, the beam steering element 800 includes, for example, Figure 7The achromatic polarization grating 700 shown includes a polarization grating 805, a polarization-dependent filter 810, and a controller 815, which provides signals to change the operating state of the polarization-dependent filter 810 between a first operating state in which the polarization-dependent filter 810 filters a first circular polarization and a second operating state in which the polarization-dependent filter 810 filters a second circular polarization.

[0073] Beam steering element 800 receives unpolarized light 820, although in some embodiments, light 820 is at least partially polarized. Polarizing grating 805 diffracts light 820 into orthogonal circularly polarized beams—for example, right-handed and left-handed circularly polarized, respectively. Order. The diffracted light is indicated by arrows 825 and 830, while orthogonal circular polarization is represented as first circular polarization 135 and second circular polarization 840. The diffracted light 825 and 830 impacts the polarization-dependent filter 810. When operating in the first state 801, the polarization-dependent filter 810 filters out the light 830 with the second circular polarization 840, and only the light 825 with the first circular polarization 835 is transmitted. When operating in the second state 802, the polarization-dependent filter 810 filters out the light 825 with the first circular polarization 835, and only the light 830 with the second circular polarization 840 is transmitted.

[0074] Figure 9 This is an illustration of an optical system implementing selective beam steering to generate an extended eyebox according to some embodiments. The optical system 800 is illustrated in a first state 901, which is considered the nominal state because the optical system in the first state 901 is transmitting unpolarized light, i.e., a 0th-order polarization grating implemented in the optical system. In the first state 901, a first image 911 generated by a display in the optical system appears at a first position in the user's field of view (FOV). When operating in a second state 902, the optical system selectively transmits light having a first circular polarization, for example, a +1 order polarization produced by the polarization grating implemented in the optical system. In the second state 902, a second image 912 generated by the display appears at a second position in the user's FOV, offset from the position of the first image 911. When operating in a third state 903, the optical system selectively transmits light having a second circular polarization, for example, a -1 order polarization produced by the polarization grating implemented in the optical system. In the third state 903, a third image 913 generated by the display appears in a third position, which is in the user's field of view (FOV) relative to the first image 911 and offset in the opposite direction to the second image 912.

[0075] Figure 10This is an illustration of an optical system 1000 that uses a beam steering element 1005 to generate an extended field of view (FOV) according to some embodiments. The optical system 1000 includes a microdisplay 1010 that generates an image and provides light represented in the image to optical elements 1015 and 1020, which provide filtered light to a light guide 1025 that directs the light to an exit position near the beam steering element 1005. As discussed herein, some embodiments of the beam steering element 1005 are implemented as liquid crystal polarization gratings. In the illustrated embodiment, the beam steering element 1005 can be switched at two different angles. Switching between the two corresponding states.

[0076] In the absence of beam steering element 1005 (or at order 0 of the polarization grating in beam steering element 1005), the light emitted from light guide 1025 covers the nominal FOV 1030. However, with the switching angle... Switching between corresponding states expands the effective field of view (FOV) perceived by the user, for example, if the switching occurs at a sufficiently high frequency. In some embodiments, the display 1010 generates interlaced frames representing scenes using different FOVs, and these frames are associated with corresponding switching angles. The switching between states is coordinated. The interleaved frames are generated by time multiplexing between a first state where the beam steering element 1005 diffracts light to the direction indicated by the switching angle +α and a second state where the beam steering element 1005 diffracts light to the direction indicated by the switching angle -α. The result of the time-multiplexed interleaved frames is an effective FOV 1035 equal to the nominal FOV 1030 plus an additional opening angle 2α. Although in Figure 10 Not depicted, but some embodiments of the optical system 1000 also include additional beam steering elements (such as... Figure 8 The beam steering element 800 shown is an additional beam steering element deployed between optical elements 1015 and 1020 and switching between multiple states to provide enhanced eyebox volume, as discussed herein.

[0077] Broadly speaking, as described above, these embodiments relate to see-through HMD devices, such as glasses, helmets, and visors, which combine computer-generated and real-world light to form a combined view or combined image to the user's eyes. To improve upon previous geometry and design, according to some embodiments, a display is placed on top of or to the side of a light guide, which is held in place in front of one or both eyes of the user via a frame in a manner similar to that of a pair of conventional eyeglasses.

[0078] The technologies used in the HMD devices described herein can be applied in conjunction with various types of displays. For example, these technologies can be used in conjunction with organic light-emitting displays (OLEDs), active-matrix OLEDs (AMOLEDs), liquid crystal on silicon (LCOS) displays, light-emitting diode (LED) displays, liquid crystal displays (LCDs), and TFT (thin-film transistor) LCDs. References to light guides herein include one or more components that reflect light based on substantial or total internal reflection (TIR) ​​between the light guide surfaces. The described embodiments combine light guides with certain components in VR-based or AR-based devices, where ambient light and display light are combined to provide a combined image to the user's eyes.

[0079] In some embodiments, certain aspects of the above-described technology are implemented using one or more processors of a processing system, which execute software such as to drive an electronic display and provide content, and to operate a PG. The software includes one or more sets of executable instructions stored or otherwise tangibly embodied on a non-transitory computer-readable storage medium. The software includes instructions and certain data that, when executed by the one or more processors, manipulate the one or more processors to perform one or more aspects of the above-described technology. The non-transitory computer-readable storage medium may include, for example, disk or optical disc storage devices, solid-state storage devices such as flash memory, cache, random access memory (RAM), or other non-volatile storage devices. The executable instructions stored on the non-transitory computer-readable storage medium may be in the form of source code, assembly language code, object code, or other instruction formats that are interpreted or otherwise executable by one or more processors.

[0080] Computer-readable storage media can include any storage medium or combination of storage media accessible to a computer system during use to provide instructions and / or data to the computer system. Such storage media can include, but are not limited to, optical media (e.g., optical discs (CDs), digital versatile discs (DVDs), Blu-ray discs), magnetic media (e.g., floppy disks, magnetic tapes, or hard magnetic drives), volatile memory (e.g., random access memory (RAM) or cache), non-volatile memory (e.g., read-only memory (ROM) or flash memory), or microelectromechanical systems (MEMS) based storage media. Computer-readable storage media can be embedded in a computing system (e.g., system RAM or ROM), fixedly attached to a computing system (e.g., a hard magnetic drive), removably attached to a computer system (e.g., an optical disc or a flash memory based on a universal serial bus (USB)), or coupled to a computer system via a wired or wireless network (e.g., network accessible memory (NAS)).

[0081] It should be noted that not all of the activities or elements generally described above are essential, and may not be required as part of a particular activity or device. Furthermore, it should be noted that one or more other activities or elements may be performed in addition to those described. Moreover, the order in which the activities are listed is not necessarily the order in which they are performed. These concepts have been described with reference to specific embodiments. However, those skilled in the art will understand that various modifications and changes can be made without departing from the scope of this disclosure as set forth in the claims. Accordingly, the specification and drawings are to be regarded as illustrative rather than restrictive, and all such modifications are intended to be included within the scope of this disclosure.

[0082] Regarding specific embodiments, benefits, other advantages, and solutions to problems have been described above. However, the benefits, advantages, solutions to problems, and any features that may lead to or make more apparent any benefit, advantage, or solution should not be construed as key, essential, or fundamental features of any or all claims. Furthermore, the embodiments disclosed above are merely illustrative, as the disclosed subject matter can be modified and practiced in different but equivalent ways that will be apparent to those skilled in the art who have benefited from the teachings herein. The construction or design details shown herein are not limited in any way except as set forth in the claims below. Therefore, it is apparent that the embodiments disclosed above can be changed or modified, and all such changes are considered to be within the scope of the disclosed subject matter. Accordingly, the protection sought herein is as set forth in the following claims.

Claims

1. Eyewear apparatus comprising: a light guide having a world-side surface and an eye-side surface; a display oriented to emit light toward the light guide; a beam steering element comprising a first polarization grating positioned along an optical path between the display and the light guide, wherein the first polarization grating is configured to diffract light emitted by the display into orders having different polarizations, wherein each of the orders is selectively transmitted into one of a plurality of different eyeboxes, and wherein the beam steering element comprises a polarization dependent filter that filters light received from the first polarization grating and a controller that provides a signal to change an operating state of the polarization dependent filter to transmit light into one of the plurality of different eyeboxes; and a frame that supports the light guide, the display, and the first polarization grating. The different polarizations include right circular polarization or left circular polarization.

2. The eyewear device of claim 1, wherein, The right circular polarization corresponds to a +1 order of the polarization grating and the left circular polarization corresponds to a -1 order of the polarization grating.

3. The eyewear device of claim 2, wherein, The first polarization grating diffracts light with a positive deviation angle for right circularly polarized light and diffracts light with a negative deviation angle for left circularly polarized light.

4. The eyewear device of claim 2, wherein, The first polarization grating is a substantially achromatic liquid crystal polarization grating.

5. The eyewear device of claim 1, wherein, The polarization dependent filter filters right circularly polarized light in a first state and left circularly polarized light in a second state, and wherein the first state is associated with a first eyebox of the plurality of different eyeboxes and the second state is associated with a second eyebox of the plurality of different eyeboxes.

6. The eyewear device of claim 2, wherein, 7. The eyewear apparatus of claim 1, further comprising: a second polarization grating positioned proximate the eye-side surface of the light guide, the second polarization grating configured to selectively transmit light emitted by the display into different fields of view (FOVs). The second polarization grating is configured to time multiplex content representing the different FOVs to present a larger effective FOV perceived by a user wearing the eyewear apparatus.

8. The eyewear device of claim 7, wherein, The second polarization grating comprises a switchable polarization grating that switches between polarizations to time multiplex the content representing the different FOVs.

9. The eyewear device of claim 8, wherein, 10. A method for an eyewear apparatus comprising: emitting light in the eyewear apparatus from a display toward a beam steering element comprising a first polarization grating, the eyewear apparatus comprising a light guide having a world-side surface and an eye-side surface, wherein the beam steering element further comprises a polarization dependent filter that filters light received from the first polarization grating and a controller that provides a signal to change an operating state of the polarization dependent filter; diffracting, by the first polarization grating, light received from the first polarization grating into orders having different polarizations; and ​ ​ based on the operating state of the polarization dependent filter, selectively transmitting, via the beam steering element, one of the diffracted orders into one eyebox of a plurality of different eyeboxes by: transmitting light associated with the one of the diffracted orders and filtering out light associated with other ones of the diffracted orders.

11. The method of claim 10, wherein, selectively transmitting the light emitted by the display into one eyebox of the plurality of eyeboxes includes generating orders having right and left circular polarizations.

12. The method of claim 11, wherein, the right circular polarization corresponds to a +1 order of the polarization grating and the left circular polarization corresponds to a -1 order of the polarization grating.

13. The method of claim 11, wherein, diffracting the light emitted by the display includes diffracting the light at a positive deviation angle for right circularly polarized light and diffracting the light at a negative deviation angle for left circularly polarized light.

14. The method of claim 10, wherein, the first polarization grating is a substantially achromatic liquid crystal polarization grating.

15. The method of claim 13, wherein, selectively transmitting one of the diffracted orders includes filtering the right circularly polarized light in a first state and the left circularly polarized light in a second state.

16. The method of claim 10, further comprising: selectively transmitting the light emitted by the display into different fields of view (FOVs) at a second polarization grating positioned proximate the eye-side surface of the light guide.

17. The method of claim 16, wherein, selectively transmitting the light includes time multiplexing content representing the different FOVs to present a larger effective FOV perceived by a user wearing the eyewear device.

18. The method of claim 17, wherein, time multiplexing the content includes switching between circular polarizations associated with the different FOVs.

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