Eye tracking fundus imaging system

Abstract

A fundus illumination system includes a light source array, a first light combiner, and a second light combiner. The light source array is configured to be selectively enabled to emit invisible light to illuminate the fundus of an eye. The first light combiner is configured to receive reflected invisible light reflected by the eye, direct a first component of the reflected invisible light to a first camera to generate an image of the eye, and pass a second component of the reflected invisible light. The second light combiner is configured to receive fundus imaging light in response to the second component of the reflected invisible light, and direct the fundus imaging light to a second camera to generate a fundus image.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 983,339, entitled “Fundus Tracking Imaging System,” filed on February 28, 2020. The entire contents of U.S. Provisional Application No. 62 / 983,339 are expressly incorporated herein by reference. Technical Field

[0003] Aspects of the present disclosure generally relate to fundus illumination and imaging systems. Background Art

[0004] Fundus imaging involves imaging (e.g., taking a photograph) of the back of the eye, also called the fundus. In particular, the fundus is the inner surface of the eye opposite the lens, and may include the retina, optic disc, macula, fovea, and posterior pole. In some cases, analysis of fundus images may be used by a care provider for diagnostic or therapeutic response purposes. For example, a doctor may be able to identify problems such as infection, degenerative eye disease, or even congenital conditions based on examination of fundus images.

[0005] Some conventional fundus imaging systems may include various optical devices and cameras capable of flash. The operation of these conventional imaging systems may include directing the patient to gaze at a target image (e.g., a dot) projected onto the retina, and then flooding the pupil with light (e.g., activating a flash) to obtain an image. Summary of the invention

[0006] In one aspect, the present invention relates to a fundus imaging system, comprising: a light source array configured to be selectively enabled to emit invisible light to illuminate the fundus of an eye; a first light combiner disposed between the light source array and the eye-facing side of the fundus imaging system, wherein the first light combiner is configured to: receive reflected invisible light reflected by the eye, direct a first component of the reflected invisible light to a first camera to generate an image of the eye, and pass a second component of the reflected invisible light; and a second light combiner disposed between the light source array and the first light combiner, wherein the second light combiner is configured to: receive fundus imaging light in response to the second component of the reflected invisible light, and direct the fundus imaging light to a second camera to generate an image of the fundus.

[0007] In an embodiment of the fundus imaging system according to the present invention, the system may also include a computing device configured to determine movement of the eye based on an image of the eye, and selectively enable at least one light source in the light source array based on the movement to maintain illumination of the fundus.

[0008] In an embodiment of the fundus imaging system according to the present invention, the invisible light may include infrared light or near-infrared light.

[0009] In an embodiment of the fundus imaging system according to the present invention, the system may further include a lens system disposed between the first light combiner and the second light combiner, wherein the lens system is configured to guide the invisible light emitted by at least one light source in the light source array to illuminate the fundus of the eye. In addition, the lens system may be configured to focus the invisible light to the pupil plane of the eye.

[0010] In an embodiment of the fundus imaging system according to the present invention, the first component of the reflected invisible light can be a first polarization orientation, and the second component of the reflected invisible light can be a second polarization orientation orthogonal to the first polarization orientation. In addition, the first light combiner can also include a first polarization volume hologram, which is configured to guide the reflected invisible light with the first polarization orientation and allow the reflected invisible light with the second polarization orientation to pass.

[0011] In an embodiment of the fundus imaging system according to the present invention, the second light combiner may be configured to guide the light to the second camera based on the wavelength of the fundus imaging light having the same wavelength as the invisible light. In addition, the second light combiner may further include a second polarization volume hologram configured to guide the fundus imaging light to the second camera based on the polarization orientation and wavelength of the fundus imaging light.

[0012] In an embodiment of the fundus imaging system according to the present invention, the second light combiner may be configured to guide the light to the second camera based on the wavelength of the fundus imaging light having the same wavelength as the invisible light. In addition, the second light combiner may further include a hot mirror configured to guide the fundus imaging light to the second camera based on the wavelength of the fundus imaging light.

[0013] In an embodiment of the fundus imaging system according to the present invention, the light source array may include a transparent substrate, and wherein each light source of the light source array is arranged on the transparent substrate.

[0014] In an embodiment of the fundus imaging system according to the present invention, the first light combiner and the second light combiner may transmit visible light.

[0015] In an embodiment of the fundus imaging system according to the present invention, the system may further include a first camera configured to generate at least one image of the eye and a second camera configured to generate at least one image of the fundus of the eye.

[0016] In one aspect, the present invention relates to a head-mounted display (HMD), comprising: a display layer configured to emit display light for presentation to a user; a light source array disposed on the display layer and configured to be selectively enabled to emit invisible light to illuminate the fundus of the user's eye; a first optical combiner disposed between the light source array and an eye-facing side of the HMD, wherein the first optical combiner is configured to: receive reflected invisible light reflected by the eye, direct a first component of the reflected invisible light to a first camera to generate an image of the eye, and pass a second component of the reflected invisible light; and a second light combiner disposed between the light source array and the first light combiner, wherein the second light combiner is configured to: receive fundus imaging light in response to the second component of the reflected invisible light, and direct the fundus imaging light to a second camera to generate an image of the fundus.

[0017] In an embodiment of the HDM according to the present invention, the first component of the reflected invisible light can be a first polarization orientation, and the second component of the reflected invisible light can be a second polarization orientation orthogonal to the first polarization orientation. In addition, the first light combiner can also include a first polarization volume hologram configured to guide the reflected invisible light with the first polarization orientation and allow the reflected invisible light with the second polarization orientation to pass.

[0018] In an embodiment of the HDM according to the present invention, the second light combiner may be configured to guide the light to the second camera based on the wavelength of the fundus imaging light having the same wavelength as the invisible light. In addition, the second light combiner may further include a second polarization volume hologram configured to guide the fundus imaging light to the second camera based on the polarization orientation and wavelength of the fundus imaging light.

[0019] In an embodiment of the HDM according to the present invention, the second light combiner may be configured to guide the light to the second camera based on the wavelength of the fundus imaging light having the same wavelength as the invisible light. In addition, the second light combiner may further include a hot mirror configured to guide the fundus imaging light to the second camera based on the wavelength of the fundus imaging light.

[0020] In an embodiment of the HDM according to the present invention, the first light combiner and the second light combiner may transmit the display light.

[0021] In one aspect, the present invention also relates to a fundus imaging system, comprising: a first camera, which is configured to generate at least one image of an eye; a second camera, which is configured to generate at least one image of the fundus of the eye; a light source array, which is configured to be selectively enabled to emit invisible light to illuminate the fundus of the eye; a first light combiner, which is arranged between the light source array and the eye-facing side of the fundus imaging system, wherein the first light combiner is configured to: receive reflected invisible light reflected by the eye, guide a first component of the reflected invisible light to the first camera to generate the at least one image of the eye, and allow a second component of the reflected invisible light to pass; and a second light combiner, which is arranged between the light source array and the first light combiner, wherein the second light combiner is configured to: receive fundus imaging light in response to the second component of the reflected invisible light, and guide the fundus imaging light to the second camera to generate the at least one image of the fundus. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Non-limiting and non-exhaustive aspects of the present disclosure are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the views unless otherwise specified.

[0023] Figure 1A and Figure 1B A fundus imaging system according to aspects of the present disclosure is shown.

[0024] Figure 2A An example image of an eye captured by a first camera for eye tracking is shown in accordance with aspects of the present disclosure.

[0025] Figure 2B An example image of the fundus captured by the second camera is shown in accordance with aspects of the present disclosure.

[0026] Figure 3 A computing device in accordance with aspects of the present disclosure is shown.

[0027] Figure 4 is a flow chart illustrating a process for imaging the fundus according to aspects of the present disclosure.

[0028] Figure 5 A head mounted display (HMD) according to aspects of the present invention is described. DETAILED DESCRIPTION

[0029] Various aspects and embodiments are disclosed in the following description and related drawings to illustrate specific examples related to fundus imaging systems including eye tracking. After reading this disclosure, alternative aspects and embodiments will be apparent to those skilled in the relevant art and may be constructed and practiced without departing from the scope or spirit of the disclosure. In addition, well-known elements will not be described in detail or may be omitted to avoid obscuring the relevant details of the aspects and embodiments disclosed herein.

[0030] In some implementations of the present disclosure, the term "near eye" may be defined to include elements configured to be placed within 50 mm of a user's eye when a near eye device is in use. Thus, a "near eye optical element" or "near eye system" would include one or more elements configured to be placed within 50 mm of a user's eye.

[0031] In various aspects of the invention, visible light may be defined as having a wavelength range of about 380nm-700nm. Invisible light may be defined as light having a wavelength outside the visible light range, such as ultraviolet light and infrared light. Infrared light having a wavelength range of about 700nm-1mm includes near infrared light. In aspects of the invention, near infrared light may be defined as having a wavelength range of about 700nm-1.4μm. White light may be defined as light that includes a wide range of wavelengths, and in some cases may include multiple colors of the visible spectrum.

[0032] As described above, the operation of some conventional fundus imaging systems may include guiding a patient (or user) to look at a target image (e.g., a point) projected onto their retina. One purpose of guiding the patient to look at the target image is to ensure proper alignment between the eye and an illumination source (e.g., a flash) to maximize illumination of the fundus. However, in some cases, due to reduced physical or developmental abilities, the patient may not be able to follow directions to look at the target. For example, a user may have eye movement problems that prevent them from focusing on the target, or an infant / child may not be able to follow directions to focus on the target, etc. If the eye is not aligned with the illumination source, the pupil of the eye will vignette the illumination and prevent light from reaching the fundus, which may degrade the resulting image.

[0033] Thus, aspects of the present invention provide a fundus imaging system that is invariant to eye movement and / or eye alignment. That is, the fundus imaging system can maintain illumination of the fundus even when the eye is not directly aligned with the illumination source and / or even when the eye moves. In one aspect, a fundus illumination source is provided that includes an array of light sources. An eye tracker that tracks eye movement may also be provided, wherein one or more light sources in the array are selectively enabled to emit illumination light based on determined eye movement to maintain illumination of the fundus while obtaining fundus images. These and other features will be described in more detail below.

[0034] Figure 1A Fundus imaging system 100 is shown in accordance with aspects of the present disclosure. Fundus imaging system 100 is also shown to include light source arrays 102A-102G, layer 104, optical combiner 106, lens system 108, optical combiner 110, first camera 120, computing device 122, and second camera 126.

[0035] like Figure 1A As shown, light sources 102A-102G are disposed on layer 104. Layer 104 can be a transparent substrate, such as glass or plastic. In one example, light sources 102A-102G can be encapsulated in a transparent substrate. The transparent substrate can transmit visible light (e.g., 400nm-750nm) and can be configured to be placed on a display plane of an electronic or optical display layer (e.g., a liquid crystal display (LCD), an organic light emitting diode (OLED) display, a micro-LED display, a waveguide, etc.), the electronic or optical display layer being configured to generate display light for presentation to a user. In another example, layer 104 itself is an electronic or optical display layer, wherein light sources 102A-102G are disposed on the display layer and dispersed in the display light generated by the display layer (e.g., within the user's field of view).

[0036] Each light source 102A-102G can be a micro light emitting diode (microLED), an edge emitting LED, a vertical cavity surface emitting laser (VCSEL) diode, or a super luminescent diode (SLED). In addition, each light source 102A-102G can be individually enabled to emit invisible light 107 to illuminate the eye 114. In some examples, the invisible light 107 is infrared light or near infrared light. In some aspects, each light source 102A-102G is arranged on layer 104 in a two-dimensional (2D) array of columns and rows. In some examples, each light source 102A-102G can be referred to as a point light source, where only one of the light sources 102A-102G is enabled to emit invisible light 107 at a time (e.g., in Figure 1A In the example shown, only a single light source 102D is currently enabled to emit invisible light 107).

[0037] In some examples, the array of light sources 102A-102G is positioned in a plane conjugate to the pupil plane 116 of the eye 114. In some implementations, the positioning of the light source array 102A-102G relative to the eye 114 is achieved by a head / chin rest (not shown) provided to the user / patient. In other implementations, the positioning of the light source array 102A-102G relative to the eye 114 is achieved by a head / chin rest (not shown) provided to the user / patient. Figure 5 head-mounted display) to provide positioning.

[0038] like Figure 1A As shown, lens system 108 is configured to receive invisible light 107 and direct invisible light 107 to illuminate fundus 112 of eye 114. In some examples, lens system 108 provides a Maxwell view, wherein lens system 108 focuses invisible light 107 onto pupil plane 116. Figure 1A As shown, invisible light 107 expands toward the back of eye 114 when passing through pupil 118 to illuminate a larger area of ​​fundus 112. In some aspects, lens system 108 includes a Fresnel lens. In other examples, lens system 108 can include one or more other optical elements, such as a quarter wave plate and / or a reflective polarizer. In some examples, invisible light 107 is generated by light sources 102A-102G to have a specific polarization orientation. Therefore, in some aspects, lens system 108 can change the polarization orientation of invisible light 107 as it propagates through the system.

[0039] Figure 1A Also shown is the fundus imaging system 100, which includes an optical combiner 106 and an optical combiner 110. The optical combiner 106 is shown as being disposed between the array of light sources 102A-102G and the optical combiner 110. In particular, the optical combiner 106 can be disposed between the array of light sources 102A-102G and the lens system 108. The optical combiner 110 is shown as being disposed between the array of light sources 102A-102G and the eye-facing side 103 of the fundus imaging system 100, and in particular can be disposed between the lens system 108 and the eye-facing side 103. As will be described in more detail below, the optical combiner 110 can be configured to direct reflected invisible light (i.e., invisible light reflected by the eye 114) to a first camera 120 to generate an image 123 of the eye 114. Similarly, the optical combiner 106 can be configured to direct reflected invisible light to a second camera 126 to produce an image 127 of the fundus 112.

[0040] In some aspects, optical combiners 106 and 110 can be transmissive to visible light (e.g., approximately 400 nm-700 nm), such as scene light (e.g., from the environment) incident on back side 105 of fundus imaging system 100. Even in some examples, optical combiners 106 and 110 are transmissive to visible light generated by display layers (e.g., layer 104). In some examples, optical combiners 106 and 110 can each be configured as a respective polarization-selective volume hologram (also referred to as a "hologram") that diffracts (reflects) a specific polarization orientation of incident light having a specific wavelength to cameras 126 and 120, respectively, while passing other polarization orientations / wavelengths.

[0041] When configured as a PVH, the light combiner may include a plurality of liquid crystal molecules that are spatially oriented to achieve the optical function of the PVH. In some examples, the PVH may be configured to diffract light via Bragg diffraction. In some embodiments, the Bragg grating in the PVH may be produced by adding a chiral dopant to the liquid crystal to induce a helical twist along the direction of light propagation. The helical twist may be left-handed or right-handed, and therefore, the PVH may be referred to as a left-handed or right-handed PVH. In some embodiments, the PVH may diffract circularly polarized light having the same handedness as the helical twist of the PVH and transmit circularly polarized light having an orthogonal handedness. That is, a left-handed PVH layer may diffract left-handed circularly polarized ("LCP") light and transmit right-handed circularly polarized ("RCP") light, while a right-handed PVH layer may diffract RCP light and transmit LCP light.

[0042] The angle between the incident light and the diffracted light can depend on the wavelength of the incident light and the Bragg period of the Bragg grating in the PVH. In some embodiments, the PVH can further converge or diverge the incident light depending on the arrangement of the liquid crystal molecules in the PVH. In some examples, the PVH of the light combiner can also be referred to as a "polarization-sensitive grating", "polarization-sensitive optical element", "liquid crystal grating" or "chiral liquid crystal element". When configured as a PVH, the light combiners 106 and 110 can include flat or curved surfaces.

[0043] In some embodiments, the light combiner 106 may alternatively be configured as a "hot mirror". When configured as a hot mirror, the light combiner 106 may include one or more reflective layers that reflect invisible light (e.g., having the same wavelength as the invisible light 107) to the second camera 126 while passing visible light. The one or more hot mirrors may be within the user's line of sight, but because the hot mirror passes visible light, external scene light and / or display light will still propagate to the user's eyes. Thus, in an augmented reality (AR) implementation, the user's view of the external environment remains visible, and in a virtual reality (VR) implementation, the user may view display light from a virtual reality display. In some examples, the hot mirror of the light combiner 106 may include a dichroic multilayer optical film that is configured to reflect a particular spectrum of invisible light and pass light of other wavelengths including visible light.

[0044] Figure 1B An imaging optical path of a fundus imaging system 100 for generating images of an eye 114 and a fundus 112 according to aspects of the present disclosure is shown. In some aspects, when illuminated by invisible light 107, each point on the fundus 112 of the eye 114 can operate as a point light source that reflects the invisible light 107 as reflected invisible light 109. In addition, the reflected invisible light 109 can leave the eye 114 nearly collimated and include multiple components (e.g., multiple polarization orientations). In some examples, one component of the reflected invisible light 109 is the same polarization orientation as the invisible light 107 incident on the fundus 112.

[0045] like Figure 1B As shown, the reflected invisible light 109 is received at the light combiner 110. The light combiner 110 may then direct the first component 111 of the reflected invisible light to the first camera 120, where the first camera 120 then generates one or more images 123 of the eye 114. Figure 2A An example image 202A is shown that may be captured by first camera 120. In some examples, first camera 120 may be configured to filter out light other than invisible light 107 / reflected invisible light 109 such that first camera 120 images only wavelengths of reflected invisible light 109.

[0046] Figure 1B Also shown is a light combiner 110 that passes a second component 113 of reflected invisible light 109. In some examples, first component 111 of reflected invisible light 109 is a first polarization orientation (e.g., RCP) and second component 113 is a second polarization orientation orthogonal to the first polarization orientation (e.g., LCP).

[0047] The second component 113 of the reflected invisible light 109 then passes through the lens system 108, which then transmits the fundus imaging light 115 in response to the second component 113. For example, in some aspects, the lens system 108 can change the polarization orientation of the reflected second component 113 of the invisible light to a different polarization orientation, and transmit the changed second component as the fundus imaging light 115. In yet another example, the lens system 108 can maintain the polarization state of the second component 113 as it propagates through the lens system as the fundus imaging light 115. In either case, when the light combiner 106 is implemented as a PVH, the PVH can be configured to reflect light having the same specific polarization orientation (and wavelength) as the fundus imaging light 115 received from the lens system 108. In some examples, the fundus imaging light 115 has the same wavelength as the reflected invisible light 109. The optical combiner 106 receives the fundus imaging light 115 and directs it to a second camera 126 , which then produces one or more images 127 of the fundus 112 . Figure 2B An example image 202B is shown that may be captured by second camera 126. In some examples, second camera 126 may be configured to filter out light other than reflected invisible light 109, such that second camera 126 images only wavelengths of reflected invisible light 109.

[0048] In some examples, fundus imaging system 100 can include an eye tracking system for tracking movement of eye 114. In the example shown, the eye tracking system is provided by first camera 120. First camera 120 is communicatively coupled to computing device 122, which is configured to track movement of eye 114 based on one or more images 123. In some examples, the eye tracking system is a pupil tracker that is configured to determine movement of the eye based on movement of pupil 118.

[0049] In some examples, the eye tracking module of computing device 122 may be configured to determine eye tracking information (e.g., the position, orientation, gaze angle, etc. of eye 114). In some aspects, the eye tracking module may be configured to receive image 123 captured by first camera 120 and process the image to detect one or more specular reflections. The eye tracking module may then locate the detected specular reflections to determine eye tracking information (e.g., the position, orientation, gaze angle, etc. of eye 114). For example, the eye tracking module may determine whether eye 114 is looking in a straight, left, right, upward, or downward direction.

[0050] In some embodiments, computing device 122 may include a control module communicatively coupled to the array of light sources 102A-102G. Figure 1AAs shown, eye 114 is generally looking forward and aligned with the center of light source array 102A-102G. Therefore, in this case, the center light source (e.g., light source 102D) can be enabled to emit invisible light 107. However, as described above, if eye 114 is not directly aligned, or if eye 114 moves, pupil 118 can blur invisible light 107. Therefore, the control module of computing device 122 can generate one or more control signals 124 to selectively enable at least one of light sources 102A-102G based on the detected movement of eye 114 to maintain illumination of fundus 112.

[0051] For example, in some aspects, each light source 102A-102G of the array of light sources may include a corresponding position within the array. The control module may be configured to translate the detected movement of the eye 114 into a position within the array in order to determine which of the light sources 102A-102G are enabled. In some embodiments, a change in which of the light sources 102A-102G is enabled changes the angle of the invisible light 107 emitted from the lens system 108. Thus, in operation, the eye tracking module of the computing device 122 may detect movement of the eye 114 based on one or more images 123, wherein the control module then translates the detected movement of the eye into a position of a light source in the array of light sources.

[0052] Figure 3 A computing device 302 is shown in accordance with aspects of the present disclosure. The illustrated example of computing device 302 is shown to include a communication interface 304, one or more processors 306, hardware 308, and memory 310. Figure 3 The computing device 302 is Figure 1A One possible implementation of computing device 122 .

[0053] Communication interface 304 may include wireless and / or wired communication components that enable computing device 302 to send data to and receive data from other devices / components. Hardware 308 may include additional hardware interfaces, data communication, or data storage hardware. For example, a hardware interface may include a data output device and one or more data input devices.

[0054] Memory 310 may be implemented using computer-readable media such as computer storage media. In some aspects, computer-readable media may include volatile and / or non-volatile, removable and / or non-removable media implemented in any method or technology for storing information such as computer-readable instructions, data structures, program modules, or other data. Computer-readable media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD), high-definition multimedia / data storage disk, or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission media that can be used to store information for access by a computing device.

[0055] The processor 306 and memory 310 of the computing device 302 may implement an eye tracking module 312 and a fundus illumination source control module 314. The eye tracking module 312 and the fundus illumination source control module 314 may include routines, program instructions, objects, and / or data structures that perform specific tasks or implement specific abstract data types. The memory 310 may also include a data store (not shown) used by the eye tracking module 312 and / or the fundus illumination source control module 314.

[0056] The eye tracking module 312 may be configured to receive an image (e.g., Figure 1B The eye tracking module 312 may then communicate with the fundus illumination source control module 314 based on the determined movement / position. The fundus illumination source control module 314 may be configured to convert the eye movement into a position within the array of light sources 102A-102G and generate one or more control signals (e.g., control signals 124) to enable at least one of the light sources 102A-102G to maintain illumination of the fundus 112.

[0057] Figure 4 4 is a flow chart illustrating a process 400 for imaging the fundus according to aspects of the present disclosure. The process 400 includes Figure 1A The computing device 122 and / or Figure 3 One or more process blocks executed by the computing device 302.

[0058] Processing block 402 includes capturing one or more images (e.g., Figure 1B123). In processing block 404, the movement of the eye 114 is tracked. As described above, the computing device 122 can analyze the image 123 to determine the position and / or movement of the eye 114. Next, in processing block 406, the computing device 122 selectively enables at least one light source in the array of light sources 102A-102G based on the movement of the eye. As described above, the enabling of the light source can include translating the movement of the eye 114 into a position within the array of light sources to maintain illumination of the fundus 112 with the invisible light 107. Next, in processing block 408, the second camera 126 can capture one or more images of the fundus 112.

[0059] In some implementations, such as Figure 1A Various aspects of the present disclosure, such as the fundus imaging system 100, may be used in a head-mounted device such as a virtual reality (VR) or augmented reality (AR) device. In some aspects, the head-mounted device may be combined with an eye tracking system to enhance the user's viewing experience. In some cases, eye tracking may be assisted by determining the position and / or movement of one or more features present in the fundus. For example, the head-mounted device may be configured to identify a foveal region from an image of the fundus, and then determine the gaze angle of the eye based on the identified foveal region. The foveal region may be determined using one or more image processing techniques. When the gaze angle is determined, the virtual image presented to the user by the display of the head-mounted device may be adjusted in response to the determined gaze angle.

[0060] As an example, Figure 5 A head mounted display (HMD) 500 is shown in accordance with various aspects of the present disclosure. An HMD (e.g., HMD 500) is a type of head mounted device that is typically worn on a user's head to provide artificial reality content to the user. Artificial reality is a form of reality that has been adjusted in some way before being presented to the user, which may include, for example, virtual reality (VR), augmented reality (AR), mixed reality (MR), hybrid reality, or some combination and / or derivative thereof. The example of the HMD 500 shown includes a viewing structure 540, a top fixing structure 541, a side fixing structure 542, a rear fixing structure 543, and a front rigid body 544. In some examples, the HMD 500 is configured to be worn on the head of a user of the HMD 500, wherein the top fixing structure 541, the side fixing structure 542, and / or the rear fixing structure 543 may include a fabric strap including an elastic member for fixing the HMD 500 to the user's head and one or more rigid structures (e.g., plastic). The HMD 500 may also optionally include one or more headphones 520 for delivering audio to the ears of a user of the HMD 500 .

[0061] The illustrated example of HMD 500 also includes an interface film 518 for contacting the face of a user of HMD 500 , where interface film 518 is used to block at least some ambient light from reaching the eyes of the user of HMD 500 .

[0062] The example HMD 500 may also include a frame for supporting hardware for the viewing structure 540 of the HMD 500 (the frame and hardware are not shown in FIG. Figure 5 ). The hardware of the viewing structure 540 may include any processing logic, wired and / or wireless data interfaces for sending and receiving data, a graphics processor, and one or more memories for storing data and computer executable instructions. In one example, the viewing structure 540 may be configured to receive wired power and / or may be configured to be powered by one or more batteries. In addition, the viewing structure 540 may be configured to receive wired and / or wireless data including video data.

[0063] The viewing structures 540 may include a display system having one or more electronic displays for directing light to the eyes of a user of the HMD 500. The display system may include one or more of a liquid crystal display (LCD), an organic light emitting diode (OLED) display, a micro-LED display, etc., for emitting light (e.g., content, images, video, etc.) to the user of the HMD 500. The viewing structures 540 may also include an optical assembly configured to receive image light from the display system and generate a virtual image for viewing by the eyes of the wearer of the HMD 500 (e.g., by collimating the image light).

[0064] In some examples, the viewing structure includes a fundus imaging system 545 for obtaining one or more images of the fundus of the user's eye. The fundus imaging system 545 can be implemented by any of the embodiments discussed herein, including Figure 1A A fundus imaging system 100 is provided.

[0065] Embodiments of the present invention may include an artificial reality system or be implemented in conjunction with an artificial reality system. Artificial reality is a form of reality that has been adjusted in some way before being presented to a user, which may include, for example, virtual reality (VR), augmented reality (AR), mixed reality (MR), mixed reality, or some combination and / or derivative thereof. Artificial reality content may include fully generated content or a combination of generated content and captured (e.g., real world) content. Artificial reality content may include video, audio, tactile feedback, or some combination thereof, and any of them may be presented in a single channel or multiple channels (such as stereoscopic video that produces a three-dimensional effect on the viewer). In addition, in some embodiments, artificial reality may also be associated with an application, product, accessory, service, or some combination thereof, which is used, for example, to create content in artificial reality and / or otherwise used for artificial reality (e.g., performing activities in artificial reality). An artificial reality system that provides artificial reality content can be implemented on a variety of platforms, including a head-mounted display (HMD) connected to a host system, a standalone HMD, a mobile device or computing system, or any other hardware platform capable of providing artificial reality content to one or more viewers.

[0066] The above description of illustrative embodiments of the present invention (including what is described in the Abstract) is not intended to be exhaustive or to limit the present invention to the precise form disclosed. Although specific embodiments and examples of the present invention are described herein for illustrative purposes, those skilled in the relevant art will recognize that various modifications may be made within the scope of the present invention.

[0067] These modifications may be made to the invention in light of the above detailed description. The terms used in the following claims should not be interpreted as limiting the invention to the specific embodiments disclosed in the specification. Instead, the scope of the invention is determined entirely by the appended claims, which should be interpreted in accordance with established principles of claim interpretation.

Claims

1. A fundus imaging system, comprising: an array of light sources configured to be selectively enabled to emit invisible light to illuminate the fundus of the eye; A first light combiner is disposed between the light source array and the eye-facing side of the fundus imaging system, wherein the first light combiner is configured as follows: receiving reflected invisible light reflected by the eye, directing a first component of the reflected invisible light to a first camera to generate an image of the eye, and passing a second component of the reflected invisible light; and A second light combiner is disposed between the light source array and the first light combiner, wherein the second light combiner is configured as follows: receiving fundus imaging light in response to the second component of the reflected invisible light, and The fundus imaging light is directed to a second camera to generate an image of the fundus.

2. The fundus imaging system according to claim 1, further comprising: A computing device is configured to determine movement of the eye based on the image of the eye, and selectively enable at least one light source in the array of light sources based on the movement to maintain illumination of the fundus. The fundus imaging system according to claim 1 , wherein the invisible light comprises infrared light. The fundus imaging system according to claim 3 , wherein the infrared light comprises near infrared light.

5. The fundus imaging system according to claim 1, further comprising: A lens system is disposed between the first light combiner and the second light combiner, wherein the lens system is configured to guide the invisible light emitted by at least one light source in the light source array to illuminate the fundus of the eye, wherein the lens system is configured to focus the invisible light onto a pupil plane of the eye.

6. The fundus imaging system according to claim 1, wherein the first component of the reflected invisible light is a first polarization orientation, and wherein the second component of the reflected invisible light is a second polarization orientation orthogonal to the first polarization orientation, wherein the first light combiner includes a first polarization body hologram, and the first polarization body hologram is configured to guide the reflected invisible light with the first polarization orientation and allow the reflected invisible light with the second polarization orientation to pass. 7 . The fundus imaging system according to claim 1 , wherein the second light combiner is configured to guide light to the second camera based on a wavelength of the fundus imaging light having the same wavelength as the invisible light.

8. The fundus imaging system according to claim 7, wherein the second light combiner comprises: a second polarization volume hologram configured to direct the fundus imaging light to the second camera based on the polarization orientation of the fundus imaging light and the wavelength; or A hot mirror is configured to guide the fundus imaging light to the second camera based on the wavelength of the fundus imaging light.

9. The fundus imaging system according to claim 1, wherein the light source array comprises: A transparent substrate, wherein each light source of the light source array is disposed on the transparent substrate.

10. The fundus imaging system of claim 1, wherein the first light combiner and the second light combiner are transmissive to visible light.

11. A head mounted display (HMD), comprising: A display layer configured to emit display light for presentation to a user; a light source array disposed on the display layer and configured to be selectively enabled to emit invisible light to illuminate the fundus of the user's eye; A first light combiner is disposed between the light source array and the eye-facing side of the HMD, wherein the first light combiner is configured to: receiving reflected invisible light reflected by the eye, directing the first component of the reflected invisible light to a first camera to generate an image of the eye, and passing a second component of the reflected invisible light; and A second light combiner is disposed between the light source array and the first light combiner, wherein the second light combiner is configured as follows: receiving fundus imaging light in response to the second component of the reflected invisible light, and The fundus imaging light is directed to a second camera to generate an image of the fundus.

12. The HMD of claim 11 , wherein the first component of the reflected invisible light is of a first polarization orientation, and wherein the second component of the reflected invisible light is of a second polarization orientation orthogonal to the first polarization orientation, wherein the first light combiner comprises a first polarization volume hologram configured to guide the reflected invisible light having the first polarization orientation and pass the reflected invisible light having the second polarization orientation. 13 . The HMD of claim 11 , wherein the second light combiner is configured to guide light to the second camera based on a wavelength of the fundus imaging light, the fundus imaging light having the same wavelength as the invisible light.

14. The HMD of claim 13, wherein the second light combiner comprises: a second polarization volume hologram configured to direct the fundus imaging light to the second camera based on the polarization orientation of the fundus imaging light and the wavelength; or A hot mirror is configured to guide the fundus imaging light to the second camera based on the wavelength of the fundus imaging light.

15. The HMD of claim 11, wherein the first light combiner and the second light combiner are transmissive to the display light.

16. A fundus imaging system, comprising: a first camera configured to generate at least one image of an eye; a second camera configured to generate at least one image of the fundus of the eye; an array of light sources configured to be selectively enabled to emit invisible light to illuminate the fundus of the eye; A first light combiner is disposed between the light source array and the eye-facing side of the fundus imaging system, wherein the first light combiner is configured as follows: receiving reflected invisible light reflected by the eye; directing the first component of the reflected invisible light to the first camera to generate the at least one image of the eye, and passing a second component of the reflected invisible light; and A second light combiner is disposed between the light source array and the first light combiner, wherein the second light combiner is configured as follows: receiving fundus imaging light in response to the second component of the reflected invisible light, and The fundus imaging light is directed to the second camera to generate the at least one image of the fundus.

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