Increased depth of field for mixed reality displays

Abstract

An optical system and a method for operating the same are disclosed. A delimited area is defined as a function of a distance from the optical system based on a VAC limit, the delimited area having at least one distance threshold. A virtual distance of a virtual depth plane from the optical system is determined, at which a virtual object is to be displayed. Whether the virtual distance is outside the delimited area is determined by comparing the virtual distance to at least one distance threshold. A collimated pixel beam associated with the virtual object is generated by a projector of the optical system. If the virtual distance is outside the delimited area, the collimated pixel beam is modified to generate a modified pixel beam. Modifying the collimated pixel beam includes converging the collimated pixel beam and / or reducing the diameter of the collimated pixel beam.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 946,291, filed on December 10, 2019, entitled “INCREASED DEPTH OF FIELD FOR MIXED-REALITY DISPLAY,” the entire contents of which are incorporated herein by reference for all purposes. Background Art

[0003] Modern computing and display technologies have facilitated the development of systems for so-called "virtual reality" or "augmented reality" experiences, in which digitally reproduced images, or portions thereof, are presented to a user in a manner that appears to be real or can be perceived as real. A virtual reality or "VR" scene typically involves the presentation of digital or virtual image information without being transparent to other actual real-world visual input; an augmented reality or "AR" scene typically involves the presentation of digital or virtual image information as an enhancement to the visualization of the real world around the user.

[0004] Regardless of the advances made in these display technologies, there is a need in the art for improved methods, systems, and apparatus related to augmented reality systems, and in particular, for improved methods, systems, and apparatus related to augmented reality display systems. Summary of the invention

[0005] The present disclosure generally relates to techniques for improving the performance and user experience of optical systems. More particularly, embodiments of the present disclosure provide systems and methods for operating a fixed focal plane optical system including a microdisplay and a leaky grating light guide pupil extension eyepiece element having a scheme for disrupting human visual system accommodation cues by dynamically extending the depth of field of the system in a compact form factor. Although the present disclosure is described with reference to an optical system such as an augmented reality (AR) device, the present disclosure is applicable to a variety of applications in computer vision and image display systems.

[0006] The following provides an overview of the present invention with reference to a series of examples. As used hereinafter, any reference to a series of examples will be understood as a reference to each of those examples separately (e.g., "Examples 1-4" will be understood as "Examples 1, 2, 3, or 4").

[0007] Example 1 is a method of operating an optical system, the method comprising: defining a demarcated area according to a distance from the optical system based on a convergence-accommodation conflict (VAC) limit, the demarcated area having at least one distance threshold; determining a virtual distance of a virtual depth plane from the optical system at which a virtual object is to be displayed; determining whether the virtual distance is outside the demarcated area by comparing the virtual distance with the at least one distance threshold; generating a collimated pixel beam associated with the virtual object by a projector of the optical system; based on determining that the virtual distance is outside the demarcated area, modifying the collimated pixel beam to generate a modified pixel beam, wherein modifying the collimated pixel beam comprises at least one of the following: converging the collimated pixel beam; or reducing the diameter of the collimated pixel beam; injecting the modified pixel beam into an eyepiece of the optical system; and outputting the modified pixel beam from the eyepiece to an eye of a user.

[0008] Example 2 is an optical system comprising: a projector configured to generate a collimated pixel beam associated with a virtual object; a light modification device configured to modify the collimated pixel beam to generate a modified pixel beam; an eyepiece configured to output the modified pixel beam; and a processing module configured to perform operations including: determining a virtual distance of a virtual depth plane from the optical system at which the virtual object is to be displayed; comparing the virtual distance with at least one distance threshold; and based on comparing the virtual distance with the at least one distance threshold, causing the light modification device to modify the collimated pixel beam to generate the modified pixel beam.

[0009] Example 3 is an optical system according to Example 2, wherein modifying the collimated pixel beam includes: converging the collimated pixel beam.

[0010] Example 4 is an optical system according to Examples 2 to 3, wherein modifying the collimated pixel beam includes: reducing the diameter of the collimated pixel beam.

[0011] Example 5 is an optical system according to Examples 2 to 4, wherein the operation further comprises: defining a demarcated area according to a distance from the optical system, the demarcated area including the at least one distance threshold.

[0012] Example 6 is an optical system according to Example 5, wherein comparing the virtual distance with the at least one distance threshold includes: determining whether the virtual distance is outside the defined area.

[0013] Example 7 is an optical system according to Examples 5-6, wherein the defined area is defined based on a VAC limit.

[0014] Example 8 is an optical system according to Example 7, wherein the VAC limit is defined by a user of the optical system.

[0015] Example 9 is an optical system according to Examples 2-8, wherein the at least one distance threshold includes an upper distance threshold.

[0016] Example 10 is an optical system according to Example 9, wherein comparing the virtual distance with the at least one distance threshold includes: determining whether the virtual distance is greater than the upper distance threshold.

[0017] Example 11 is an optical system according to Example 10, wherein modifying the collimated pixel beam based on comparing the virtual distance with the at least one distance threshold includes: in response to determining that the virtual distance is greater than the upper distance threshold, causing the light modification device to modify the collimated pixel beam.

[0018] Example 12 is an optical system according to Examples 2-11, wherein the at least one distance threshold includes a lower distance threshold.

[0019] Example 13 is an optical system according to Example 12, wherein comparing the virtual distance to the at least one distance threshold includes: determining whether the virtual distance is less than the lower distance threshold.

[0020] Example 14 is an optical system according to Example 13, wherein modifying the collimated pixel beam based on comparing the virtual distance with the at least one distance threshold includes: in response to determining that the virtual distance is less than the lower distance threshold, causing the light modification device to modify the collimated pixel beam.

[0021] Example 15 is an optical system according to Examples 2-14, wherein the eyepiece is configured to receive the modified pixel light beam from the light modifying device.

[0022] Example 16 is an optical system according to Examples 2-15, wherein the light modifying device is located in the optical path between the projector and the eyepiece.

[0023] Example 17 is a method of operating an optical system, the method comprising: determining a virtual distance of a virtual depth plane from the optical system at which a virtual object is to be displayed; comparing the virtual distance with at least one distance threshold; generating a collimated pixel beam associated with the virtual object by a projector of the optical system; and modifying the collimated pixel beam to generate a modified pixel beam based on comparing the virtual distance with the at least one distance threshold.

[0024] Example 18 is a method according to Example 17, wherein modifying the collimated pixel beam includes: converging the collimated pixel beam.

[0025] Example 19 is a method according to Examples 17-18, wherein modifying the collimated pixel beam includes: reducing the diameter of the collimated pixel beam.

[0026] Example 20 is a method according to Examples 17-19, further comprising: defining a defined area based on a distance from the optical system, the defined area including the at least one distance threshold.

[0027] Example 21 is a method according to Example 20, wherein comparing the virtual distance with the at least one distance threshold includes: determining whether the virtual distance is outside the defined area.

[0028] Example 22 is a method according to Examples 20-21, wherein the defined area is defined based on VAC restrictions.

[0029] Example 23 is a method according to Example 22, wherein the VAC limit is defined by a user of the optical system.

[0030] Example 24 is a method according to Examples 17-23, wherein the at least one distance threshold includes an upper distance threshold.

[0031] Example 25 is a method according to Example 24, wherein comparing the virtual distance with the at least one distance threshold includes: determining whether the virtual distance is greater than the upper distance threshold.

[0032] Example 26 is a method according to Example 25, wherein modifying the collimated pixel beam based on comparing the virtual distance with the at least one distance threshold includes: modifying the collimated pixel beam in response to determining that the virtual distance is greater than the lower distance threshold.

[0033] Example 27 is a method according to Examples 17-26, wherein the at least one distance threshold includes a lower distance threshold.

[0034] Example 28 is a method according to Example 27, wherein comparing the virtual distance to the at least one distance threshold comprises: determining whether the virtual distance is less than the lower distance threshold.

[0035] Example 29 is a method according to Example 28, wherein modifying the collimated pixel beam based on comparing the virtual distance with the at least one distance threshold includes: modifying the collimated pixel beam in response to determining that the virtual distance is less than the lower distance threshold.

[0036] Example 30 is a method according to Examples 17-29, further comprising: injecting the modified pixel light beam into an eyepiece of the optical system.

[0037] Example 31 is a method according to Examples 17-30, further comprising: outputting the modified pixel light beam from an eyepiece of the optical system to an eye of a user.

[0038] Example 32 is a method according to Examples 17-31, wherein the collimated pixel light beam is modified by a light modifying device located in the optical path between the projector and the eyepiece of the optical system.

[0039] The present disclosure achieves many benefits over conventional techniques. For example, embodiments enable a single focal plane system to have many of the same benefits as a dual focal plane system, such as reduced VAC in both the near and far virtual depth planes. In addition, because the pixel beams can be modified prior to injection into the eyepiece, embodiments are compatible with existing eyepieces that employ pupil expansion combiner eyepiece technology. Embodiments also eliminate the need for a crop plane that is often used for the near depth plane, thereby reducing the inconvenience to the user due to disappearance of virtual content. Other benefits of the present disclosure will be readily apparent to those skilled in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings, which are incorporated in this specification and form a part thereof, and are included to provide a further understanding of the present disclosure, illustrate embodiments of the present disclosure and, together with the detailed description, serve to explain the principles of the present disclosure. No attempt is made to show the structural details of the present disclosure and the various ways in which it can be practiced in more detail than is necessary for a basic understanding of the present disclosure.

[0041] Figure 1 An augmented reality (AR) scene as viewed through a wearable AR device is shown.

[0042] Figure 2A An AR device with a single fixed focal plane is shown.

[0043] Figure 2B An AR device with two fixed focal planes is shown.

[0044] Figure 3 The relationship between the vergence-accommodation conflict (VAC) and the distance to the virtual depth plane is shown.

[0045] Figure 4 A schematic diagram of an example wearable AR device is shown.

[0046] Figure 5 Example functionality of viewing optics components of an AR device and the resulting user visual perception of system output are shown.

[0047] Figure 6 Example functionality of viewing optics components of an AR device and the resulting user visual perception of system output are shown.

[0048] Figure 7 Example functionality of viewing optics components of an AR device and the resulting user visual perception of system output are shown.

[0049] Figure 8 Example functionality of viewing optics components of an AR device and the resulting user visual perception of system output are shown.

[0050] Fig. 9 Example functionality of viewing optics components of an AR device and the resulting user visual perception of system output are shown.

[0051] FIG. 10A to FIG. 10C An example light-modifying device for reducing the diameter of a collimated pixel light beam is shown.

[0052] Fig.11 Example control schemes for light-modifying devices and corresponding user visual perception of system outputs are shown.

[0053] Fig.12 An example method for defining a VAC demarcation area is shown.

[0054] Fig.13 Various examples of VAC demarcation areas are shown.

[0055] Fig.14 An example method of operating an optical system is shown.

[0056] Fig.15 A simplified computer system is shown.

[0057] In the drawings, identical components and / or features may have identical numerical reference labels. Further, various components of the same type may be distinguished by following the reference label with a letter, or by following the reference label with a dash followed by a second numerical reference label that distinguishes between similar components and / or features. If only the first numerical reference label is used in the specification, the description applies to any of the similar components and / or features having the same first numerical reference label regardless of the suffix. DETAILED DESCRIPTION

[0058] Mixed reality (MR) and augmented reality (AR) wearable displays are able to present virtual content to users over a wide range of depths. For many displays, users may experience different levels of accommodation-convergence conflict (VAC) at different depths, which occurs when the user's brain receives mismatch cues between the distance of a virtual object from the user's eyes and the focus distance required for the eyes to focus on the virtual object. VAC causes visual fatigue, headaches, nausea, and eyestrain, and remains a significant source of user discomfort. Therefore, in order to keep users comfortable, modern MR and AR wearable displays may consider VAC budget limits when delivering virtual content over a range of depths, which may result in a significantly reduced depth range.

[0059] Various approaches to mitigate VAC have been implemented. One approach includes adding a second depth plane to the optical system and a zoom switch based on eye tracking. Another approach is to add a zoom element with the ability to scan the eyepiece focal plane across a wide range. These approaches add bulk in the form of additional eyepiece layers and / or by integrating a pair of liquid-fillable adjustable lenses that span the eyepiece, as well as added complexity due to complex illumination schemes.

[0060] Some embodiments of the present invention provide an optical system with a demarcated area within which a user tolerates a limited amount of VAC, and outside of which an extended depth of field can be turned on to disrupt human visual system accommodation cues. In some embodiments, the demarcated area can be defined based on a single or multiple fixed focal planes or a single or multiple variable focal planes. Virtual content with an associated virtual depth plane located within the demarcated area can be projected to the user in a normal manner, while virtual content outside the demarcated area is modified by a light modification device to reduce the reliability of accommodation cues.

[0061] In some instances, the light modification device can cause the collimated light generated by the projector to become convergent when entering the eyepiece. This causes the virtual image light (i.e., light associated with the virtual image) coupled out of the leakage grating of the eyepiece to also be converged. However, the main light of each sub-beam does not change direction, resulting in a virtual image with convergence cues but very weak accommodation cues. In the depth of field region where the VAC will exceed the threshold tolerance, such a virtual image may destroy the convergence-accommodation response. Therefore, the embodiments disclosed herein can extend the depth of field of the optical system because the user's eye may not be able to focus on the pixels at the virtual depth plane. Additionally or alternatively, the light modification device can reduce the diameter of each collimated pixel beam generated by the projector. This may cause the light coupled out of the leakage grating of the eyepiece to also have a pixel beam of reduced diameter, thereby destroying the accommodation cues associated with the coupled-out light.

[0062] In some instances, an optical see-through (OST) AR device can improve the virtual content presented to a user by applying optical power to the virtual image light using one or more lens assemblies arranged within an optical stack. Embodiments of the present invention are compatible with existing systems that utilize lens assemblies to change the virtual depth plane of a virtual object.

[0063] Figure 1 An AR scene 100 as viewed through a wearable AR device is shown in accordance with some embodiments. The AR scene 100 is depicted in which a user of the AR technology sees a real-world park-like setting 106 featuring various real-world objects 130 in the background, such as people, trees, buildings, and a real-world concrete platform 120. In addition to these items, the user of the AR technology also perceives that they "see" various virtual objects 102 such as a robotic statue 102-2 and a flying cartoon-like avatar character 102-1 that appears to be an avatar of a bumblebee standing on the real-world concrete platform 120, even though these elements (character 102-1 and statue 102-2) do not exist in the real world. Due to the extreme complexity of human visual perception and the nervous system, it is challenging to produce virtual reality (VR) or AR technology that promotes a comfortable, natural feeling, rich rendering of virtual image elements among other virtual or real-world image elements.

[0064] Figure 2A An AR device 200A with a single fixed focal plane is shown in accordance with some embodiments. During operation, a projector 214 of the AR device 200A can project virtual image light 223 (i.e., light associated with virtual content) onto an eyepiece 202-1, which can cause a light field (i.e., an angular representation of the virtual content) to be projected onto a user's retina in a manner such that the user perceives the corresponding virtual content as being positioned at a location within the user's environment. For example, the virtual image light 223 coupled out by the eyepiece 202-1 can cause the user to perceive the character 102-1 as being positioned at a first virtual depth plane 210-1 and the statue 102-2 as being positioned at a second virtual depth plane 210-2. The user perceives the virtual content together with world light 232 corresponding to one or more world objects 230 (such as the platform 120).

[0065] In some embodiments, the AR device 200A includes a first lens assembly 205-1 located on the user side of the eyepiece 202-1 (the side of the eyepiece 202-1 closest to the user's eyes) and a second lens assembly 205-2 located on the world side of the eyepiece 202-1. Each of the lens assemblies 205-1, 205-2 can be configured to apply a refractive power to light passing therethrough.

[0066] Figure 2BAn AR device 200B with two fixed focal planes is shown in accordance with some embodiments. During operation, the projector 214 can project virtual image light 223 to the first eyepiece 202-1 and the second eyepiece 202-2, which may cause the light field to be projected onto the user's retina in a manner such that the user perceives the corresponding virtual content as being positioned at a certain location within the user's environment. For example, the virtual image light 223 coupled out by the first eyepiece 202-1 can cause the user to perceive the character 102-1 as being positioned at the first virtual depth plane 210-2 and the virtual image light 223 coupled out by the second eyepiece 202-2 can cause the user to perceive the statue 102-2 as being positioned at the second virtual depth plane 210-2.

[0067] Figure 3 Reference Figure 2A and Figure 2B The relationship between the VAC and the distance of the virtual depth plane for each of the AR devices 200A, 200B is described. For AR device 200B, the dual focal plane system provides switchable focal planes at 1.95 diopters (0.51 meters) and 0.65 diopters (1.54 meters), with a switch point at 1.3 diopters (0.77 meters), a near content limit (crop plane) at 2.7 diopters (0.37 meters), and the ability to provide images with no more than 1.0 diopters VAC between this plane and infinity. For AR device 200A, the single fixed focal plane system has a focal plane position at 1.5 diopters (0.6 meters) and a near content limit of 2.5 diopters (0.4 meters) and a far content limit of 0.31 diopters (3.2 meters), assuming a maximum allowed VAC of 1.0 diopters. Such a configuration would have a usable range of 0.4-3.2 meters, with content falling outside of this range requiring some solution to mitigate exceeding the VAC limits.

[0068] Figure 4A schematic diagram of an example wearable AR device 400 according to some embodiments of the present invention is shown. The AR device 400 may include a left eyepiece 402A and a left lens assembly 405A arranged in a side-by-side configuration and a right eyepiece 402B and a right lens assembly 405B also arranged in a side-by-side configuration. In some embodiments, the AR device 400 includes one or more sensors, including but not limited to: a left-front facing world camera 406A, which is directly attached to the left eyepiece 402A or near the left eyepiece 402A; a right-front facing world camera 406B, which is directly attached to the right eyepiece 402B or near the right eyepiece 402B; a left-facing world camera 406C, which is directly attached to the left eyepiece 402A or near the left eyepiece 402A; and a right-facing world camera 406D, which is directly attached to the right eyepiece 402B or near the right eyepiece 402B. In some embodiments, the AR device 400 includes one or more image projection devices, such as a left projector 414A, which is optically linked to the left eyepiece 402A, and a right projector 414B, which is optically linked to the right eyepiece 402B.

[0069] Some or all of the components of AR device 400 may be head-mounted so that the projected images can be viewed by the user. Figure 4 All components of the AR device 400 are shown mounted to a single device (e.g., a single head-mounted device) that can be worn by a user. In another embodiment, one or more components of the processing module 450 are physically separated from other components of the AR device 400 and communicatively coupled to the other components of the AR device 400 through one or more wired and / or wireless connections. For example, the processing module 450 may include a local module 452 on a head-mounted portion of the AR device and a remote module 456 that is physically separated from the local module 452 and communicatively linked to the local module 452. The remote module 456 can be mounted in a variety of configurations, such as being fixedly attached to a frame, fixedly attached to a helmet or hat worn by a user, embedded in headphones, or otherwise removably attached to the user (e.g., in a backpack-type configuration, a belt-coupled configuration, etc.).

[0070] Module 450 may include a processor and associated digital memory, such as non-volatile memory (e.g., flash memory), both of which may be used to assist in the processing, caching, and storage of data. The data may include data captured from a sensor (which may, for example, be operatively coupled to AR device 400) or otherwise attached to the user, such as camera 406, an ambient light sensor, an eye tracker, a microphone, an inertial measurement unit, an accelerometer, a compass, a GPS unit, a radio, and / or a gyroscope. For example, processing module 450 may receive (one or more) images 420 from camera 406. Specifically, processing module 450 may receive (one or more) left front images 420A from left front facing world camera 406A, receive (one or more) right front images 420B from right front facing world camera 406B, receive (one or more) left side images 420C from left side facing world camera 406C, and receive (one or more) right side images 420D from right side facing world camera 406D. In some embodiments, image(s) 420 may include a single image, a pair of images, a video including an image stream, a video including a paired image stream, etc. Image(s) 420 may be generated periodically and sent to processing module 450 when AR device 400 is powered on, or may be generated in response to instructions sent by processing module 450 to one or more of the cameras. As another example, processing module 450 may receive ambient light information from an ambient light sensor. As another example, processing module 450 may receive gaze information from one or more eye trackers. As another example, processing module 450 may receive image information (e.g., image brightness values) from one or both of projectors 414.

[0071] Cameras 406A, 406B may be positioned to capture images that substantially overlap within the fields of view of the user's left and right eyes, respectively. Thus, the camera 406 may be positioned near the user's eyes, but not too close to obscure the user's field of view. Alternatively or additionally, cameras 406A, 406B may be positioned to align with the coupling-in locations of virtual image lights 422A, 422B, respectively. Cameras 406C, 406D may be positioned to capture images of one side of the user, for example, within the user's peripheral vision or outside the user's peripheral vision. Image(s) 420C, 420D captured using cameras 406C, 406D do not necessarily need to overlap with image(s) 420A, 420B captured using cameras 406A, 406B.

[0072] The eyepieces 402A, 402B may include a transparent or semi-transparent waveguide, respectively, which is configured to guide and couple out the light generated by the projectors 414A, 414B. Specifically, the processing module 450 may cause the left projector 414A to output the left virtual image light 422A to the left eyepiece 402A, and may cause the right projector 414B to output the right virtual image light 422B to the right eyepiece 402B. In some embodiments, each of the eyepieces 402A, 402B may include a plurality of waveguides corresponding to different colors. In some embodiments, the lens assemblies 405A, 405B may be coupled to the eyepieces 402A, 402B and / or integrated with the eyepieces 402A, 402B. For example, the lens assemblies 405A, 405B may be included in a multi-layer eyepiece and may form one or more layers constituting one of the eyepieces 402A, 402B.

[0073] In some embodiments, the AR device 400 includes one or more light modification devices 404A, 404B for modifying the virtual image light 422A, 422B. Specifically, the left light modification device 404A can be positioned in the optical path between the left projector 414A and the left eyepiece 402A to modify the left virtual image light 422A before being output to the left eyepiece 402A, and the right light modification device 404B can be positioned in the optical path between the right projector 414B and the right eyepiece 402B to modify the right virtual image light 422B before being output to the right eyepiece. In some embodiments, the light modification devices 404A, 404B can be integrated with the projectors 414A, 414B. In some embodiments, the light modification devices 404A, 404B can be integrated with the eyepieces 402A, 402B.

[0074] In some embodiments, the projectors 414A, 414B may include a micro-electromechanical system (MEMS) spatial light modulator (SLM) scanning device. In such embodiments, the light modification devices 404A, 404B may employ a zoom mirror or lens that may be used in the laser beam prior to the scanning mirror. If a relay optical system is used, one of the optical elements within the relay optical system may be variable focus and may be switched to provide convergent pixel light to the ICG formed on the eyepiece. If a standard projection system is used with a pixel-based SLM such as a liquid crystal on silicon (LCOS), the SLM itself may be translated in the z-axis (perpendicular to the array) so that the projection lens produces a finite external focal plane (and therefore a converging pixel array). In some embodiments, a zoom lens may be incorporated between the projection / relay lens of the microdisplay and the ICG of the eyepiece itself to convert the output collimated pixel light into a converging state.

[0075] Figure 5An example function of an observation optical assembly 500 of an AR device and a user's visual perception of the resulting system output is shown. The observation optical assembly 500 includes a projector 514 and an eyepiece 502. The projector 514 generates a collimated pixel beam 516, which is carried to the eyepiece 502 at an input coupling grating (ICG) 503 formed on the eyepiece 502. After being diffracted by the ICG 503, the collimated pixel beam 516 propagates in the eyepiece 502 until the output grating formed on the eyepiece 502 diffracts the light toward the user.

[0076] A leaky grating light guide pupil expansion eyepiece with no programmed refractive power produces a virtual image at infinity. The perception is produced by multiple output "sub-beams" (emitted replicas of the input pixel wavefront) that are collected by the pupil and imaged onto the retina of the user's eye. In this case, when the user's eye is focused at infinity, a sharp pixel image is formed on the retina. When the eye is focused on another plane (e.g., at 1.33 meters from the user), a blurred image of the pixel is formed on the retina.

[0077] Figure 6 An example function of an observation optical assembly 600 of an AR device and a user's visual perception of the resulting system output is shown. The observation optical assembly 600 includes a projector 614 that generates a collimated pixel beam 616 that is carried to the eyepiece 602 at an ICG 603 formed on the eyepiece 602. After being diffracted by the ICG 603, the collimated pixel beam 616 propagates in the eyepiece 602 until an output grating formed on the eyepiece 602 diffracts the light toward the user.

[0078] The viewing optical assembly 600 includes a -0.75 diopter lens assembly 605 that modulates the wavefronts of the emitted beamlets, causing them to diverge relative to each other and diverging each ray independently to focus the pixel light and converge the beamlets at 1.33 meters from the user's eye. The lens assembly 605 displaces the chief ray of the emerging beamlets and diverges the collimated output to a single pixel focus position at the focal length of the lens. In this case, when the user's eye is focused at 1.33 meters, a sharp pixel image is formed on the retina. When the eye is focused at infinity, the image is blurred.

[0079] exist Figure 6 In the example shown, the depth of focus of the image is determined by multiple factors, including the beamlet packing density (determined by the beam diameter, eyepiece substrate thickness, and multiple other factors), the size of the user's pupil, the optical quality of the lens assembly 605, and the inherent depth of field of the user's eye. Each of these factors can be considered to determine an acceptable VAC budget number for the system. In some embodiments, 1.0 diopters can be used as the VAC budget number, although this value can be higher or lower in practice.

[0080] Figure 7 Example functionality of an observation optical assembly 700 of an AR device and a user visual perception of the resulting system output is shown. The observation optical assembly 700 includes a projector 714 that generates a collimated pixel beam 716, which is modified by a light modification device 704 to produce a modified pixel beam 752 having a converging wavefront. The modified pixel beam 752 is carried to the eyepiece 702 at an ICG 703 formed on the eyepiece 702. After being diffracted by the ICG 703, the modified pixel beam 752 propagates in the eyepiece 702 until an output grating formed on the eyepiece 702 diffracts the light toward the user.

[0081] exist Figure 7 In the example shown, modifying the wavefront of the imaging pixel introduces refractive power into the projection system, converting an infinitely focused system into one that produces a finite image position in front of the projector. In such a configuration, a single pixel produces a converging (curved) wavefront at the pupil plane of the projector. When the converging pixel light enters the eyepiece, the outgoing beamlets maintain that convergence, however, the chief ray of each beamlet does not change direction. In this case, when the user's eye is focused at 1.33 meters or at infinity, a blurred image of the pixel is formed on the retina. Furthermore, the perceived pixel when the user's eye is focused at 1.33 meters may be different from the perceived pixel when the user's eye is focused at infinity, as shown in FIG. Figure 7 The different types of blur are depicted in Figure 2.

[0082] Figure 8 Example functionality of an observation optical assembly 800 of an AR device and a user visual perception of the resulting system output is shown. The observation optical assembly 800 includes a projector 814 that generates a collimated pixel beam 816, which is modified by a light modification device 804 to produce a modified pixel beam 852 having a converging wavefront. The modified pixel beam 852 is carried to the eyepiece 802 at an ICG 803 formed on the eyepiece 802. After being diffracted by the ICG 803, the modified pixel beam 852 propagates in the eyepiece 802 until an output grating formed on the eyepiece 802 diffracts the light toward the user. The observation optical assembly 800 also includes a -0.75 diopter lens assembly 805 located between the eyepiece 802 and the user's eye, which modulates the wavefront of the emitted sub-beam.

[0083] exist Figure 8In the example shown, the lens assembly 805 collimates each beamlet output while redirecting the principal ray of each beamlet to pivot about a point at the focal plane of the lens. Thus, when the user's eye is focused at 1.33 meters, a blurred image of pixels is formed on the retina. When the user's eye is focused at infinity, a perception of a repeating structure including the blurred image is produced. The user's eye is unable to focus the blurred image, thereby disrupting the user's physiological vergence-accommodation cues and reducing the uncomfortable effects of vergence-accommodation conflict. This perception of a repeating structure allows virtual content to exist on a plane outside the VAC threshold. Thus, the depth of field of the optical system can be extended beyond the VAC threshold without discomfort because the user's eye will not be able to focus on pixels at the virtual depth plane.

[0084] Fig. 9 Example functionality of an observation optical assembly 900 of an AR device and a user visual perception of the resulting system output is shown. The observation optical assembly 900 includes a projector 914 that generates a collimated pixel beam 916 that is modified by a light modification device 904, such as a spatial light modulator (SLM), relay optics, polarizers, beam splitters, lenses, or a combination thereof, to produce a modified pixel beam 952 having a reduced diameter. The modified pixel beam 952 is carried to the eyepiece 902 at an ICG 903 formed on the eyepiece 902. After being diffracted by the ICG 903, the modified pixel beam 952 propagates in the eyepiece 902 until an output grating formed on the eyepiece 902 diffracts the light toward the user. The observation optical assembly 900 also includes a lens assembly 905 that includes a -1 diopter component located between the eyepiece 902 and the user's eye and a +1 diopter component located on the world side of the eyepiece 902.

[0085] exist Fig. 9 In the example shown, the vergence-accommodation cue is destroyed and the depth of field of the system is extended by modulating the diameter of the laser beam rather than by divergence / convergence of the image light. This can be performed by a light modification device 904 before injecting the light into the ICG 903. In this case, the perception is driven by the inability of the lens assembly between the eyepiece 902 and the user's eye to provide a small focal spot due to the reduction in pixel beam size.

[0086] FIG. 10A to FIG. 10C An example light modification device for reducing the diameter of a collimated pixel beam according to some embodiments of the present invention is shown. By changing the position of the second lens 1004 relative to the first lens 1002 and the third lens 1006, the diameter of the input collimated pixel beam can be enlarged, reduced, or kept unchanged. Fig. 10A, the second lens 1004 is adjusted to be positioned closer to the first lens 1002 (eg, adjacent to the first lens 1002) than the third lens 1006, so that the diameter of the collimated pixel light beam becomes enlarged when leaving the light-modifying device. Fig. 10B , the second lens 1004 is adjusted to be located at the midpoint between the first lens 1002 and the third lens 1006 so that the diameter of the collimated pixel beam remains unchanged when leaving the light modification device. Fig. 10C , the second lens 1004 is adjusted to be positioned closer to the third lens 1006 (eg, adjacent to the third lens 1006) than the first lens 1002, such that the diameter of the collimated pixel light beam becomes smaller when leaving the light-modifying device.

[0087] In some embodiments, FIG. 10A to FIG. 10C The light modification device shown is used to dynamically change the diameter of a MEMs laser beam.In some examples, the light modification device may be positioned before the MEMs mirror(s) to modify the laser beam before entering the MEMs mirror(s).

[0088] Fig.11 An example control scheme for a light modifying device and corresponding user visual perception of a system output according to some embodiments of the invention are shown. In some embodiments, a VAC demarcation region 1102 is defined based on a desired VAC limit, such as 1 diopter. The VAC demarcation region 1102 may include: a lower distance threshold 1104 below which the VAC experienced by the user exceeds the VAC limit; and an upper distance threshold 1106 above which the VAC experienced by the user exceeds the VAC limit.

[0089] Under the control scheme, when it is determined that the distance of the virtual depth plane (from the AR device or user) is less than the lower distance threshold 1104, the light modification device is caused to modify the wavefront of the collimated pixel beam. When it is determined that the distance of the virtual depth plane is greater than the lower distance threshold 1104 and less than the upper distance threshold 1106 (i.e., within the VAC demarcated area 1102), the light modification device is caused not to modify the collimated pixel beam and output the collimated pixel beam without modification. When it is determined that the distance of the virtual depth plane is greater than the upper distance threshold 1106, the light modification device is caused to modify the wavefront of the collimated pixel beam.

[0090] The control scheme may optionally implement a gradual modification of the collimated pixel beam at or near a distance threshold. For example, the light-modifying device may impart a partial modification to the collimated pixel beam at a virtual distance just before the distance threshold, a greater modification at the distance threshold, and a complete modification when well beyond the distance threshold. As an example, for an upper distance threshold of 3.2 meters, a control scheme may be implemented in which the collimated pixel beam converges 0% for a virtual distance of 2.8 meters, 25% for a virtual distance of 3.0 meters, 50% for a virtual distance of 3.2 meters, 75% for a virtual distance of 3.4 meters, and 100% for a virtual distance of 3.6 meters. In the same or different example, for a lower distance threshold of 0.4 meters, a control scheme may be implemented in which the collimated pixel beam converges 0% for a virtual distance of 0.6 meters, 25% for a virtual distance of 0.5 meters, 50% for a virtual distance of 0.4 meters, 75% for a virtual distance of 0.3 meters, and 100% for a virtual distance of 0.2 meters. Control schemes with longer or shorter transition bands than those in the examples above may be implemented. Various changes, substitutions, and modifications will occur to those of ordinary skill in the art.

[0091] Fig.12 An example method for defining a VAC demarcation area 1202 according to some embodiments of the present invention is shown. First, the VAC experienced by the user is plotted as a function of the distance of the virtual depth plane from the AR device (alternatively also referred to as a "VAC map"). In some embodiments, the VAC map is determined based on the focal plane design of the AR device. Fig.12 The VAC map shown uses a 0.75 meter focal plane. Next, the VAC limits are plotted along with the VAC experienced by the user. Next, the intersections 1204, 1206 between the two maps are identified and the corresponding distances are used as the lower and upper distance thresholds for the VAC region 1202, respectively.

[0092] Fig.13 Various examples of VAC demarcation areas that can be defined based on VAC diagrams for various single focal plane systems are shown. As the focal plane of the AR device increases, the lower and upper distance thresholds of the VAC demarcation area increase, presenting a tradeoff between near and far view performance. Additional depth planes can be added to the system to increase the VAC demarcation area.

[0093] Fig.14An example method 1400 of operating an optical system (e.g., AR device 400) according to some embodiments of the present invention is shown. One or more steps of method 1400 may be performed in a different order than the illustrated embodiment, and one or more steps of method 1400 may be omitted during execution of method 1400. In addition, two or more steps of method 1400 may be performed simultaneously or concurrently with each other.

[0094] At step 1402, VAC delineated areas (e.g., VAC delineated areas 1102, 1202) are defined. In some embodiments, the VAC delineated areas are defined based on the number of focal planes of the optical device and / or their corresponding focal plane positions. For example, the VAC associated with a single focal plane system having a focal plane position at 1.5 diopters can be estimated and used to determine a VAC delineated area, which can be significantly smaller than a VAC delineated area determined using a VAC associated with a multi-focal plane system, such as a dual focal plane system having focal plane positions at 1.95 diopters and 0.65 diopters. In some embodiments, the VAC delineated areas are additionally (or alternatively) defined based on VAC limits, which can be specified by a user or can be predetermined by the system. In some embodiments, the VAC delineated areas are defined by finding (one or more) intersection points (e.g., intersection points 1204, 1206) between the VAC associated with the optical system and the VAC limits, such as with reference to at least Figure 3 , Fig.12 and Fig.13 As described.

[0095] In some embodiments, a VAC delimited area is defined based on a distance from the optical system, wherein the distance within the VAC delimited area corresponds to a virtual depth plane at which the virtual content causes the user to experience a VAC that is less than the VAC limit, and the distance outside the VAC delimited area corresponds to a virtual depth plane at which the virtual content causes the user to experience a VAC that is greater than the VAC limit. In some embodiments, the VAC delimited area includes at least one distance threshold. For example, the VAC delimited area may include a lower distance threshold (e.g., lower distance threshold 1104) and / or an upper distance threshold (e.g., upper distance threshold 1106), the lower distance threshold being less than the upper distance threshold.

[0096] At step 1404, a virtual distance of a virtual depth plane (e.g., virtual depth plane 210) from an optical system to display a virtual object (e.g., virtual object 102) is determined. The virtual distance may be expressed in meters, diopters, or some other unit indicating a physical displacement. In some embodiments, the virtual distance is determined by a processing module (e.g., processing module 450). In some embodiments, the virtual distance is determined before, during, or after a collimated pixel beam associated with the virtual object is generated by the optical system.

[0097] At step 1406, the virtual distance is compared to a lower distance threshold and / or an upper distance threshold. In some embodiments, it is determined whether the virtual distance is less than the lower distance threshold, greater than the lower distance threshold and less than the upper distance threshold, or greater than the upper distance threshold. For example, in some embodiments, step 1406 may include determining whether the virtual distance is less than the lower distance threshold. As another example, in some embodiments, step 1406 may include determining whether the virtual distance is greater than the upper distance threshold. As another example, in some embodiments, step 1406 may include determining whether the virtual distance is less than the lower distance threshold or greater than the upper distance threshold. In some embodiments, step 1406 is equivalent to determining whether the virtual distance is outside the VAC demarcated area.

[0098] At step 1408, a collimated pixel beam (e.g., collimated pixel beam 516, 616, 716, 816, 916) associated with the virtual object is generated by the optical system. In some embodiments, the collimated pixel beam is generated by a projector (e.g., projector 214, 414, 514, 614, 714, 814, 914) of the optical system. The collimated pixel beam may include color, brightness, and size information for displaying the virtual object. For example, the collimated pixel beam may include light from a single LED color source (e.g., red) or from multiple LED color sources (e.g., red, green, and blue).

[0099] At step 1410, the collimated pixel beam is modified to generate a modified pixel beam (e.g., modified pixel beam 752, 852, 952). In some embodiments, the collimated pixel beam is modified by a light modification device of the optical system (e.g., light modification device 404, 704, 804, 904). In some embodiments, whether step 1410 is performed may depend on the comparison performed in step 1406. For example, in some embodiments, step 1410 is performed only when it is determined that the virtual distance is outside the VAC demarcated area. For example, step 1410 may be performed only in response to determining that the virtual distance is less than a lower distance threshold or in response to determining that the virtual distance is greater than an upper distance threshold. In some embodiments, the light modification device is integrated with the projector. In some embodiments, the light modification device is separate from the projector.

[0100] In some embodiments, step 1410 includes step 1412 and / or step 1414. At step 1412, the collimated pixel beam is converged. In some embodiments, the collimated pixel beam is converged by a light modification device. At step 1414, the diameter of the collimated pixel beam is reduced. In some embodiments, the diameter of the collimated pixel beam is reduced by a light modification device.

[0101] At step 1416, the modified pixel beam is injected into the eyepiece of the optical system (e.g., eyepiece 202, 402, 502, 602, 702, 802, 902). In some embodiments, the modified pixel beam is injected into an ICG formed on the eyepiece (e.g., ICG 503, 603, 703, 803, 903).

[0102] At step 1418, the modified pixel beam is output from the eyepiece of the optical system. In some embodiments, the modified pixel beam is output from a leakage grating formed on the eyepiece. In some embodiments, the modified pixel beam is output from the eyepiece toward the user's eye.

[0103] Fig.15 1 shows a simplified computer system 1500 according to the embodiments described herein. Fig.15 The computer system 1500 shown may be incorporated into the devices described herein. Fig.15 A schematic diagram of one embodiment of a computer system 1500 is provided that can perform some or all of the steps of the methods provided by various embodiments. It should be noted that Fig.15 It is intended only to provide a generalized illustration of the various components, any or all of which may be used as appropriate. Fig.15 It is broadly shown how individual system elements may be implemented in a relatively discrete or relatively more integrated manner.

[0104] A computer system 1500 is shown that includes hardware elements that may be electrically coupled via a bus 1505 or that may otherwise communicate as appropriate. The hardware elements may include one or more processors 1510, including but not limited to one or more general-purpose processors and / or one or more special-purpose processors, such as digital signal processing chips, graphics acceleration processors, and / or the like; one or more input devices 1515, which may include but are not limited to a mouse, keyboard, camera, and / or the like; and one or more output devices 1520, which may include but are not limited to a display device, a printer, and / or the like.

[0105] The computer system 1500 may also include and / or communicate with one or more non-transitory storage devices 1525, which may include, but are not limited to, local and / or network access storage, and / or may include, but are not limited to, disk drives, drive arrays, optical storage devices, solid-state storage devices, such as random access memory ("RAM") and / or read-only memory ("ROM"), which may be programmable, flash-updated, and / or the like. Such storage devices may be configured to implement any suitable data storage, including, but not limited to, various file systems, database structures, and / or the like.

[0106] The computer system 1500 may also include a communication subsystem 1519, which may include but is not limited to a modem, a network card (wireless or wired), an infrared communication device, a wireless communication device, and / or a chipset such as a Bluetooth TM Devices, 802.11 devices, WiFi devices, WiMax devices, cellular communication facilities, etc. and / or the like. The communication subsystem 1519 may include one or more input and / or output communication interfaces that allow data to be exchanged with a network (such as the network described below, to name just one example), other computer systems, televisions, and / or any other device described herein. Depending on the desired functionality and / or other implementation issues, a portable electronic device or similar device can transmit images and / or other information via the communication subsystem 1519. In other embodiments, a portable electronic device (e.g., a first electronic device) can be included in the computer system 1500, for example, as an electronic device of the input device 1515. In some embodiments, the computer system 1500 will also include a working memory 1535, which can include a RAM or ROM device, as described above.

[0107] The computer system 1500 may also include software elements shown as currently located within the working memory 1535, including an operating system 1540, device drivers, executable libraries, and / or other code, such as one or more application programs 1545, which may include computer programs provided by various embodiments, and / or may be designed to implement methods, and / or configure systems provided by other embodiments, as described above. By way of example only, one or more programs described with respect to the methods discussed above may be implemented as code and / or instructions executable by a computer and / or a processor within a computer; in one aspect, then, such code and / or instructions may be used to configure and / or adapt a general purpose computer or other device to perform one or more operations according to the described methods.

[0108] The set of these instructions and / or codes may be stored on a non-transitory computer-readable storage medium, such as the storage device(s) 1525 described above. In some cases, the storage medium may be contained within a computer system, such as computer system 1500. In other embodiments, the storage medium may be separate from the computer system, for example, a removable medium, such as an optical disk, and / or provided in an installation package so that the storage medium can be used to program, configure, and / or adapt a general-purpose computer using the instructions / codes stored thereon. These instructions may take the form of executable code that can be executed by computer system 1500 and / or may take the form of source and / or installable code, which is based on compilation and / or installation on computer system 1500, for example, using any of the commonly available compilers, installers, compression / decompression utilities, etc., and then takes the form of executable code.

[0109] It will be apparent to those skilled in the art that substantial variations may be made depending on specific requirements. For example, custom hardware may also be used, and / or specific elements may be implemented in hardware, software (including portable software, such as applets, etc.), or both. Further, connections to other computing devices such as network input / output devices may be employed.

[0110] As mentioned above, in one aspect, some embodiments may use a computer system, such as computer system 1500, to perform methods according to various embodiments of the technology. According to one set of embodiments, some or all of the processes of such methods are performed by computer system 1500 in response to processor 1510 executing one or more sequences of one or more instructions, which may be included in operating system 1540 and / or other code, such as application programs 1545 contained in working memory 1535. Such instructions may be read into working memory 1535 from another computer-readable medium, such as one or more of storage devices 1525. By way of example only, execution of the sequences of instructions contained in working memory 1535 may cause processor(s) 1510 to perform one or more processes of the methods described herein. Additionally or alternatively, portions of the methods described herein may be performed by dedicated hardware.

[0111] As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any medium that participates in providing data that causes a machine to operate in a particular manner. In an embodiment implemented using computer system 1500, various computer-readable media may be involved in providing instructions / code to (one or more) processors 1510 for execution and / or may be used to store and / or carry such instructions / code. In many embodiments, computer-readable media are physical and / or tangible storage media. Such media may take the form of non-volatile media or volatile media. Non-volatile media include, for example, optical and / or magnetic disks, such as (one or more) storage devices 1525. Volatile media include, but are not limited to, dynamic memory, such as working memory 1535.

[0112] Common forms of physical and / or tangible computer readable media include, for example, floppy disks, diskettes, hard disks, magnetic tape, or any other magnetic medium, CD-ROMs, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, RAM, PROM, EPROM, FLASH-EPROM, any other memory chip or cassette, or any other medium from which a computer can read instructions and / or code.

[0113] Various forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to processor(s) 1510 for execution. By way of example only, the instructions may initially be carried on a magnetic disk and / or optical disk of a remote computer. The remote computer may load the instructions into its dynamic memory and send the instructions as signals over a transmission medium to be received and / or executed by computer system 1500.

[0114] The communication subsystem 1519 and / or its components will typically receive the signal, and the bus 1505 may then carry the signal and / or the data, instructions, etc. carried by the signal to the working memory 1535, from which the instructions are retrieved and executed by the processor(s) 1510. The instructions received by the working memory 1535 may optionally be stored on the non-transitory storage device 1525 before or after execution by the processor(s) 1510.

[0115] The methods, systems, and devices discussed above are exemplary. Various configurations may omit, replace, or add various processes or components as appropriate. For example, in alternative configurations, the methods may be performed in an order different from the order described, and / or the stages may be added, omitted, and / or combined. Moreover, the features described with respect to certain configurations may be combined in various other configurations. Different aspects and elements of the configurations may be combined in a similar manner. Moreover, technology evolves, and therefore many of the elements are examples and do not limit the scope of the present disclosure or the claims.

[0116] Specific details are given in the description that provides a thorough understanding of exemplary configurations (including embodiments). However, the configuration can be practiced without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques have been shown without unnecessary details in order to avoid confusing configurations. This specification only provides example configurations and does not limit the scope, applicability, or configuration of the claims. On the contrary, the foregoing description of the configuration will provide an enabling description for implementing the described technology to those skilled in the art. Various changes can be made to the functions and arrangements of the elements without departing from the spirit or scope of the present disclosure.

[0117] Moreover, a configuration may be described as a process depicted as a schematic flow chart or block diagram. Although each configuration may describe an operation as a sequential process, many operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. The process may have additional steps not included in the figure. In addition, examples of methods may be implemented by hardware, software, firmware, middleware, microcode, hardware description language, or any combination thereof. When implemented in software, firmware, middleware, or microcode, the program code or code segments that perform the necessary tasks may be stored in a non-transitory computer-readable medium such as a storage medium. The processor may perform the described tasks.

[0118] A number of example configurations have been described, and various modifications, alternative configurations, and equivalents may be used without departing from the spirit of the present disclosure. For example, the above elements may be components of a larger system, wherein other rules may be superior to or otherwise modify the application of the technology. Moreover, a number of steps may be taken before, during, or after considering the above elements. Therefore, the above description is not in conjunction with the scope of the claims.

[0119] As used herein and in the following claims, the singular forms "a", "an", and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to "a user" includes a plurality of such users and reference to "a processor" includes reference to one or more processors and equivalents thereof known to those skilled in the art, and so forth.

[0120] Furthermore, when used in this specification and in the following claims, the words "comprises," "comprising," "containing," "containing," "includes," "including," and "comprising" are intended to specify the presence of stated features, integers, components, or steps, but do not exclude the presence or addition of one or more other features, integers, components, steps, actions, or combinations.

[0121] It should also be understood that the examples and embodiments described herein are for illustrative purposes only, and that various modifications or changes thereto will be suggested to those skilled in the art and are to be included within the spirit and purview of the present application and the scope of the claims.

Claims

1. A method of operating an optical system, the method comprising: Based on a vergence-accommodation conflict VAC limit, defining a delimited area according to a distance from the optical system, the delimited area having at least one distance threshold, wherein within the delimited area, a user tolerates a limited amount of vergence-accommodation conflict VAC; determining a virtual distance of a virtual depth plane from the optical system at which a virtual object is to be displayed; determining whether the virtual distance is outside the defined area by comparing the virtual distance to the at least one distance threshold; generating, by a projector of the optical system, a collimated pixel beam associated with the virtual object; Based on determining that the virtual distance is outside the defined area, modifying the collimated pixel beam to generate a modified pixel beam to switch to an extended depth of field to disrupt accommodation cues of a human visual system, wherein modifying the collimated pixel beam comprises at least one of: converging the collimated pixel beam; or reducing the diameter of the collimated pixel beam; injecting the modified pixel beam into an eyepiece of the optical system; and The modified pixel light beam is output from the eyepiece to the user's eye.

2. An optical system comprising: a projector configured to generate a collimated pixel beam associated with the virtual object; a light modification device configured to modify the collimated pixel beam to generate a modified pixel beam; an eyepiece configured to output the modified pixel light beam; as well as A processing module configured to perform operations including: determining a virtual distance of a virtual depth plane from the optical system at which the virtual object is to be displayed; comparing the virtual distance to at least one distance threshold; as well as causing the light-modifying device to modify the collimated pixel beam to generate the modified pixel beam to switch to an extended depth of field to disrupt accommodation cues of a human visual system based on comparing the virtual distance to the at least one distance threshold; as well as A delimited area is defined according to a distance from the optical system, the delimited area having at least one distance threshold, wherein within the delimited area a user tolerates a limited amount of vergence-accommodation conflict VAC.

3. The optical system according to claim 2, wherein: Modifying the collimated pixel beam comprises: The collimated pixel beam is focused.

4. The optical system according to claim 2, wherein: Modifying the collimated pixel beam comprises: The diameter of the collimated pixel beam is reduced.

5. The optical system according to claim 2, wherein: Comparing the virtual distance to the at least one distance threshold comprises: It is determined whether the virtual distance is outside the defined area.

6. The optical system according to claim 2, wherein: The demarcated area is defined based on the convergence-regulation conflict VAC limits.

7. The optical system according to claim 6, wherein: The convergence-accommodation conflict VAC limit is defined by the user of the optical system.

8. The optical system according to claim 2, wherein: The eyepiece is configured to receive the modified pixel light beam from the light modifying device.

9. The optical system according to claim 2, wherein: The light modifying device is located in the optical path between the projector and the eyepiece.

10. A method of operating an optical system, the method comprising: determining a virtual distance of a virtual depth plane from the optical system at which a virtual object is to be displayed; comparing the virtual distance to at least one distance threshold; generating, by a projector of the optical system, a collimated pixel beam associated with the virtual object; modifying the collimated pixel beam to generate a modified pixel beam to switch to an extended depth of field to disrupt accommodation cues of a human visual system based on comparing the virtual distance to the at least one distance threshold; as well as A delimited area is defined according to a distance from the optical system, the delimited area having at least one distance threshold, wherein within the delimited area a user tolerates a limited amount of vergence-accommodation conflict VAC.

11. The method according to claim 10, wherein: Modifying the collimated pixel beam comprises: The collimated pixel beam is focused.

12. The method according to claim 10, wherein: Modifying the collimated pixel beam comprises: The diameter of the collimated pixel beam is reduced.

13. The method according to claim 10, wherein: Comparing the virtual distance to the at least one distance threshold comprises: It is determined whether the virtual distance is outside the defined area.

14. The method according to claim 10, wherein: The demarcated area is defined based on the convergence-regulation conflict VAC limits.

15. The method according to claim 14, wherein: The convergence-accommodation conflict VAC limit is defined by the user of the optical system.

16. The method according to claim 11, further comprising: The modified pixel beam is injected into an eyepiece of the optical system.

17. The method according to claim 11, further comprising: The modified pixel light beam is output from an eyepiece of the optical system toward an eye of a user.

18. The method according to claim 11, wherein: The collimated pixel light beam is modified by a light modification device located in the light path between the projector and an eyepiece of the optical system.

Images