Tunable lens with deformable reflector
Patent Information
- Authority / Receiving Office
- TW · TW
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2022-05-31
- Publication Date
- 2023-06-01
Smart Images
Figure TWG2TA000909906_001 
Figure TWG2TA000909906_002 
Figure TWG2TA000909906_003
Abstract
Description
[Technical Field]
[0001] This invention relates to optical devices, and more particularly to adjustable optical elements and visual display devices using such adjustable optical elements. Reference to related applications.
[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 230,344, filed August 6, 2021, entitled “Lens with Deformable Reflector”, and U.S. Non-Provisional Patent Application No. 17 / 411,647, filed August 25, 2021, which are incorporated herein by reference in their entirety. [Previous Technology]
[0003] Visual displays are used to provide information to viewers, including still images, videos, data, etc. Visual displays have applications in a variety of fields, including entertainment, education, engineering, science, professional training, and advertising, to name just a few. Some visual displays (such as televisions) display images to multiple users, while some visual display systems are intended for individual users. Visual displays can be viewed directly or with the aid of specific glasses that may include optical shields and specific zoom lenses.
[0004] Artificial reality systems typically include near-eye displays (e.g., headphones or a pair of glasses) configured to present content to a user. Near-eye displays can display images of virtual objects or combinations of real and virtual objects, as in virtual reality (VR), augmented reality (AR), or mixed reality (MR) applications. For example, in an AR system, a user can view images of virtual objects (e.g., computer-generated images (CGI)) superimposed onto their surroundings. In some near-eye displays, each of the user's eyes views an image displayed on a small display panel. The image can be observed via an eyepiece.
[0005] Compact and efficient display systems are required for head-mounted displays. Since HMD or NED displays are typically worn on the user's head, larger, bulky, unbalanced, and / or heavy display devices would be cumbersome and potentially uncomfortable for the user. Compact display devices require compact and efficient light sources, bezels, display panels, eyepieces, etc. [Summary of the Invention]
[0006] One embodiment of the present invention is a lens comprising: a first reflector and a second reflector opposite to each other; wherein the first reflector is configured to at least partially transmit a light beam passing through it to illuminate the second reflector; wherein the second reflector is configured to at least partially reflect the light beam propagating through the first reflector back to the first reflector; wherein the first reflector is further configured to at least partially reflect the light beam reflected by the second reflector back to the second reflector; wherein the second reflector is further configured to at least partially transmit the light beam reflected by the first reflector; and wherein at least one of the first reflector or the second reflector can be deformed by applying a control signal to tune the optical power of the lens.
[0007] Another aspect of the present invention is a near-eye display (NED), comprising: a display panel for providing an image in a linear domain; and an adjustable eyepiece for converting the image in the linear domain into an image in an angular domain at an eye window of the NED, the adjustable eyepiece comprising opposing first and second reflectors; wherein the first reflector is configured to at least partially transmit a light beam passing through it to illuminate the second reflector; wherein the second reflector is configured to at least partially reflect the light beam propagating through the first reflector back to the first reflector; wherein the first reflector is further configured to at least partially reflect the light beam reflected by the second reflector back to the second reflector; wherein the second reflector is further configured to at least partially transmit the light beam reflected by the first reflector; and wherein at least one of the first or second reflector can be deformed by applying a control signal for tuning the adjustable eyepiece.
[0008] Another aspect of the present invention is a disc lens comprising: a partial reflector; a linear reflective polarizer; and a quarter-wave plate located in the optical path between the partial reflector and the linear reflective polarizer; wherein at least one of the partial reflector or the linear reflective polarizer is curved; and wherein at least one of the partial reflector or the linear reflective polarizer includes a flexible film that can be deformed by applying a control signal for tuning the optical power of the disc lens.
Implementation Method
[0010] Although this teaching is described in conjunction with various specific examples and instances, it is not intended that this teaching be limited to such specific examples. Rather, as those skilled in the art will understand, this teaching covers various alternatives and equivalents. All statements herein describing the principles, forms, and specific examples of the invention, as well as specific examples thereof, are intended to cover both structural and functional equivalents. Furthermore, it is intended that such equivalents include both currently known equivalents and future-developed equivalents, that is, any element developed to perform the same function, regardless of its structure.
[0011] As used herein, the terms “first,” “second,” etc., are not intended to imply a sequence, but rather to distinguish one element from another unless explicitly stated otherwise. Similarly, the sequence of method steps does not imply the order in which they are performed, unless explicitly stated otherwise.
[0012] Presenting simulated or augmented scenes to users of near-eye displays can cause visual fatigue and nausea. This is because existing headphones are unable to properly compensate for the difference between eye convergence and eye focus in order to adjust visual distance. This problem is called convergence-accommodation conflict. Convergence-accommodation conflict arises because the user's eye convergence changes depending on the virtual object being viewed. Eye accommodation (i.e., focus) is usually fixed and determined by the distance between the electronic display that generates the virtual image and the lens system that projects the image into the user's eye.
[0013] One solution to the convergence-diffraction conflict problem in near-eye display systems based on small display panels viewed through an eyepiece is to move the display panel back and forth according to the convergence-diffraction angle of the object displayed on the display panel. This physical movement of the display panel causes speed and reliability issues. Another solution is to zoom the eyepiece, such as the lens of the eye itself, i.e., dynamically tune or change the optical power (i.e., focusing or defocusing power) of the eyepiece to adapt to changes in the eye's convergence-diffraction.
[0014] For example, the solutions described herein provide compact zoom lenses that can not only change the optical power but also adapt to the eye prescription requirements of potential users (such as astigmatism). The zoom lens of the present invention may be based on a so-called pie lens, which includes refractive and reflective optical elements in an optical path folded by polarization. A pie lens may include two reflectors, a polarization-selective reflector and a partial reflector. By placing at least one of these reflectors onto a flexible deformable film, the shape of the reflector can be dynamically changed as needed. For example, the shape may be modified to include changing the variable spherical or parabolic component of the focal point and changing the cylindrical component of astigmatism. Various other shapes are also conceivable.
[0015] According to the present invention, a lens is provided, comprising a first reflector and a second reflector opposite to each other. The first reflector is configured to at least partially transmit a light beam passing through the first reflector to illuminate the second reflector. The second reflector is configured to at least partially reflect the light beam propagating through the first reflector back to the first reflector. The first reflector is further configured to at least partially reflect the light beam reflected by the second reflector back to the second reflector. The second reflector is further configured to at least partially transmit the light beam reflected by the first reflector. At least one of the first reflector or the second reflector can be deformed by applying a control signal to tune the optical power (i.e., focusing or defocusing power) of the lens.
[0016] In some specific examples, the first reflector includes a partial mirror, such as a 50 / 50 mirror. In a specific example where the second reflector includes a reflective polarizer, the lens may further include a quarter-wave plate between the first and second reflectors for converting the polarization state of the beam from a first polarization state to a second orthogonal polarization state after the beam has traveled two paths through the quarter-wave plate. The reflective polarizer may be, for example, a linear reflective polarizer.
[0017] In some specific embodiments, at least one of the first or second reflectors includes a flexible membrane that can be deformed by applying a radial force to its periphery. In a specific embodiment where the lens includes a support ring disposed in concentric contact with the flexible membrane, the support ring has a diameter smaller than the diameter of the flexible membrane, and the flexible membrane can be deformed by applying a force component to its periphery to press the flexible membrane against the support ring, such that the force component is parallel to the optical axis of the lens.
[0018] In a specific example where the flexible film includes an electroactive material layer, at least one of the first reflector or the second reflector may further include a transparent electrode layer and a conductive reflective layer, and the electroactive material layer may be disposed between the transparent electrode layer and the conductive reflective layer.
[0019] In some specific examples, both the first reflector and the second reflector can be deformed by applying a control signal to tune the optical power of the lens. At least one refractive lens element may be disposed between the first reflector and the second reflector.
[0020] According to the present invention, a near-eye display (NED) is provided, comprising: a display panel for providing an image in a linear domain; and an adjustable eyepiece for converting the image in the linear domain into an image in the angular domain at the eye window of the NED, wherein the adjustable eyepiece includes any of the adjustable lenses disclosed herein. In a specific example where the first reflector includes a partial mirror and the second reflector includes a linear reflective polarizer, the adjustable eyepiece may further include a quarter-wave plate between the first reflector and the second reflector for converting the polarization state of the light beam from a first polarization state to a second orthogonal polarization state after the light beam has traveled through the quarter-wave plate in a two-way propagation.
[0021] In a specific example in which at least one of the first reflector or the second reflector includes a flexible membrane, the flexible membrane can be deformed by applying a radial force to the periphery of the flexible membrane, and / or by applying a force component to the periphery of the flexible membrane to press the flexible membrane against the support ring mentioned above, such that the force component is parallel to the optical axis of the adjustable eyepiece.
[0022] In some specific examples, at least one of the first reflector or the second reflector includes a flexible film, which is stacked to include: a transparent electrode layer; an electroactive material layer; and a conductive reflective layer. The electroactive material layer may be disposed between the transparent electrode layer and the conductive reflective layer.
[0023] According to the present invention, a disc lens is further provided. The disc lens includes a partial reflector, a linear reflective polarizer, and a quarter-wave plate in the optical path between the partial reflector and the linear reflective polarizer. At least one of the partial reflector or the linear reflective polarizer may be flexible. At least one of the partial reflector or the linear reflective polarizer may include a flexible film that can be deformed by applying a control signal to tune the optical power of the disc lens. The flexible film can be deformed by applying a radial force to the periphery of the flexible film; and / or applying a force component to the periphery of the flexible film to press the flexible film against the aforementioned support ring; the force component is parallel to the optical axis of the disc lens.
[0024] The flexible film may be stacked and includes: a transparent electrode layer; an electroactive material layer; and a conductive reflective layer. The electroactive material layer may be disposed between the transparent electrode layer and the conductive reflective layer.
[0025] Referring now to FIG. 1A, lens 100 includes opposing first reflectors 111 and second reflectors 112, and, depending on the circumstances, first refractive lens element 101 and second refractive lens element 102 arranged in series between the first reflector 111 and the second reflector 112. Lens 100 can serve as an adjustable eyepiece for viewing an image in the linear domain displayed on a small display panel 106 at a short distance by converting an image in the linear domain into an image in the angular domain at the pupil 110 of the eyeball. Throughout this document and throughout the rest of this specification, the term "image in the linear domain" refers to an image in which individual pixels are represented by pixel linear coordinates, i.e., the number of columns and rows of the display panel, and the term "image in the angular domain" refers to an image in which individual pixels are represented by the angle of a collimated beam at the pupil 110 of the eyeball.
[0026] The first reflector 111 is configured to at least partially transmit the light beam 104 passing through the first reflector 111 to illuminate the second reflector 112. The second reflector 112 is configured to at least partially reflect the light beam 104 propagating through the first reflector 111 back to the first reflector 111. The first reflector 111 is further configured to at least partially reflect the light beam 104 reflected by the second reflector 112 back to the second reflector 112. The second reflector 112 is further configured to at least partially transmit the light beam 104 reflected by the first reflector 111 to the pupil 110 of the eyeball.
[0027] Lens 100 possesses optical power due to the presence of elements with optical power. For example, the first reflector 111 may be curved, as shown in FIG1A. The first refractive lens element 101 and the second refractive lens element 102, selected as appropriate, may also provide optical power to lens 100. The curvature of individual optical elements may be selected to offset or reduce overall optical aberrations. At least one or both of the first reflector 111 or the second reflector 112 may be deformed by applying a control signal in the form of an electrical signal, mechanical pressure, or force to tune lens 100, i.e., to controllably change the optical power of the lens.
[0028] A particular exemplary arrangement of the first reflector 111 and the second reflector 112 will now be considered. The first reflector 111 may be a partial reflector, such as a 50 / 50 mirror, which reflects the same amount of light during its transmission; that is, the transmitted light and the reflected light have the same light energy per unit time. The second reflector 112 may be a reflective polarizer, such as a linear reflective polarizer. The lens 100 may further include a quarter-wave plate (QWP) 108 disposed between the first reflector 111 and the second reflector 112 for converting the polarization state of the beam 104 from a first polarization state to a second orthogonal polarization state after the beam has traveled through the QWP 108 in a two-way propagation. In FIG. 1A, the QWP 108 is shown as laminated onto the first refractive lens element 101 as a non-limiting example.
[0029] Figure 1B illustrates the optical path of beam 104 folded using a reflective polarizer, a QWP, and a partial reflector. The display panel 106 may include a linear transmission polarizer 120 coupled to the display-side QWP 122. The beam 104 emitted from the display panel 106 becomes left-circularly polarized (LCP) after propagating through the display-side QWP 122.
[0030] The LCP beam 104 propagates through the first reflector 111, i.e., the 50 / 50 reflectors in this specific example, and illuminates the QWP 108, which converts the polarization state to a linear polarization state of 45 degrees. The second reflector 112 (i.e., the linear reflective polarizer in this specific example) is configured to reflect 45-degree linearly polarized light, so the beam 104 is reflected from the second reflector 112 and propagates back through the QWP 108, which converts the polarization state back to LCP. After reflection from the first reflector 111, the LCP beam 104 becomes right circularly polarized (RCP) because the propagation direction of the beam 104 changes. The RCP beam 104 propagates through the QWP 108, becomes linearly polarized at 135 degrees, and is transmitted to the pupil 110 of the eye by the reflective polarizer. It should be noted that the polarization state and the angle of linear polarization are only meant as examples, and other configurations for folding the beam path according to polarization are possible.
[0031] Lens 100 is a specific example of a pie lens that can be used as an eye lens for a near-eye display. The polarization beam folding of the pie lens achieves an extremely compact overall NED setup. This pie lens includes: a partial reflector (first reflector 111); a linear reflective polarizer (second reflector 112); and a quarter-wave plate (QWP 108) located in the optical path between the partial reflector and the linear reflective polarizer. At least one of the partial reflector or the linear reflective polarizer may be curved to provide optical power for the pie lens; and at least one of the partial reflector or the linear reflective polarizer may include a flexible film that can be deformed by applying a control signal to tune the optical power of the pie lens.
[0032] Figure 1C illustrates the "offset to angle" function of lens 100. The coordinates of pixels 106A to 106E of display panel 106 are converted into the incident angles of image beams 104A to 104E emitted from the corresponding pixels 106A to 106E to the viewer's pupil 110, thereby converting the image in the linear domain displayed by display panel 106 into an image in the angular domain at the viewer's pupil 110.
[0033] Turning to FIG. 1D for comparison with FIG. 1C, the first reflector 111 may include a flexible film supporting a reflective polarizer. In FIG. 1C, the flexible film is curved, thereby increasing the focal length of the lens 100. This is demonstrated by the fact that, compared to FIG. 1C, the pixels 106A to 106E, which are spaced further apart in FIG. 1D, have similar output angles for the image beams 104A to 104E. In FIG. 1C and FIG. 1D, for ease of illustration, the image beams 104A to 104E are traced back from the viewer's pupil 110 to the display panel 106. At least one of the first reflector 111 or the second reflector 112 may include a flexible film whose radius of curvature and associated optical power can be changed by applying an external signal.
[0034] Several non-limiting examples of deformable reflectors based on flexible films will now be considered. Referring first to FIG2A, a deformable reflector 200 includes a flexible film 202 supporting a reflective layer 204, such as a partial reflector or a reflective polarizer. The flexible film 202 may be mounted in a ring 206. When a radial force (i.e., perpendicular to the optical axis 210 of the deformable reflector 200) is applied to the ring 206, as illustrated by arrow 208 in FIG2B, the flexible film 202 changes its shape from nearly flat to curved. Astigmatism of the reflective layer 204 may be introduced by providing a non-uniform radial compressive force 208 to the periphery of the flexible film 202. The flexible film 202 may be slightly pre-bent in its initial state to disrupt symmetry and define the direction in which the flexible film 202 will bend after the radial force 208 is applied.
[0035] Turning to FIG. 3A, the deformable reflector 300 is a specific example of the first reflector 111 and / or the second reflector 112 of the lens 100 of FIGS. 1A to 1D. The deformable reflector 300 of FIG. 3A includes a flexible film 302 supporting a reflective layer 304, such as a partial reflector or a reflective polarizer. A support ring 306 is positioned to contact the flexible film 302 concentrically. The support ring 306 has a diameter smaller than the diameter of the flexible film 302. The flexible film 302 can be deformed by applying a force component indicated by arrow 308 to the periphery of the flexible film 302 to press the flexible film 302 against the support ring 306. The force component in the direction of arrow 308 is parallel to the optical axis 310 of the adjustable lens 300, thereby bending the flexible film 302, as indicated by the dashed line 302*.
[0036] In Figure 3B, the deformable reflector 300 is shown in plan view. The intensity of force components 308-1 to 308-8 can be varied such that the deformable film 302 and the reflective layer 304 adopt an asymmetrical shape to compensate for various ocular defects, such as astigmatism, as defined by the prescription of the eye's lens. The application of force components 308-1 to 308-5 can result in the formation of an approximately cylindrical lens with optical power (i.e., focusing / defocusing power) in the vertical plane 312, and the application of force components 308-3 and 308-7 can result in the formation of an approximately cylindrical lens with optical power in the horizontal plane 314, and so on.
[0037] Referring to FIG4, the deformable reflector 400 is a specific example of the first reflector 111 and / or the second reflector 112 of the lens 100 of FIG1A to FIG1D. The deformable reflector 400 of FIG4 includes an electroactive material (such as polyvinylidene fluoride (PVDF)) layer 402, which may be supported by a back layer 403 bonded to the electroactive material layer 402. A reflective layer 404 may be supported by the back layer 403. Suitable back layer materials include: polymers, such as polymethyl methacrylate, polycarbonate, or cyclic polyolefins; glass; ceramics, such as sapphire; and combinations thereof. The Young's modulus of the back layer 403 may be greater than the Young's modulus of the electroactive material layer 402 to provide greater elasticity to the deformable reflector 400. A ring spring 406 may support the deformable reflector 400 around its periphery. The annular spring 406 can have spatially variable stiffness around the periphery of the deformable reflector 400. The predetermined stiffness can be provided, for example, by varying the modulus of the spring material, the shape of the spring 406, or a combination of both.
[0038] Referring to Figures 5A and 5B, the deformable reflector 500 is a specific example of the first reflector 111 and / or the second reflector 112 of the lens 100 of Figures 1A to 1D. The deformable reflector 500 of Figures 5A and 5B includes a flexible film 520 mounted on a ring 515. The flexible film 520 includes a stack of the following layers (Figure 5B): a first electrode layer 502 that combines the functions of an electrode and a flexible reflector, a first material 504, a second electrode layer 506, a second material 508, and a reflective electrode layer 510. When an electric field is applied to the first material 504 and / or the second material 508 by means of the first electrode layer 502, the second electrode layer 506, and the reflective electrode layer 510, the flexible film 520 deforms, causing a change in the optical power (i.e., the focusing or defocusing power) of the reflective electrode layer 510. It can provide at least one transparent electrode layer and a conductive reflective layer, and an electroactive material layer disposed between the transparent electrode layer and the conductive reflective layer.
[0039] The first material 504 may be, for example, a piezoelectric material or an electrostrictive polymer. The first electrode layer 502 and the second electrode layer 506 may be, but are not limited to, transparent conductive oxides, such as indium tin oxide (ITO) or indium gallium zinc oxide (IGZO); or nanowire electrodes; graphene or carbon nanotube electrodes; metal electrodes (including aluminum or silver); or multilayer optical stacks of, for example, ITO and silver thin films. The electrostrictive material may be an acrylate elastomer, polysiloxane, PVDF-TrFE-CTF, and the like. The piezoelectric material may be PVDF, PVDF-TrFE polymer, or ceramics, such as PMN-PT, PZT, LiNbO3, and the like. For a single-crystal film, either the first material 504 or the second material 508 may be a passive material, such as a polymer, glass, or ceramic, or a combination thereof. The rigidity of the ring 515 may be spatially variable.
[0040] Turning to FIG. 6, the near-eye display (NED) 600 may include any of the adjustable lenses disclosed herein. The NED 600 includes a display panel 106 coupled to the lens 100 of FIG. 1A through FIG. 1D or any variation of the lens 100 considered herein. The display panel 106 is configured to provide an image in a linear domain, that is, an image in which the individual pixels of the image are represented by the number of columns and rows of the individual pixels of the display panel 106. Three such display panel pixels are shown in FIG. 6: a first pixel 601, a second pixel 602, and a third pixel 603. The second pixel 602 is a coaxial pixel, that is, the second pixel 602 is disposed on the optical axis 613 of the lens 100, while the first pixel 601 and the third pixel 603 are off-axis pixels disposed away from the optical axis 613.
[0041] Lens 100 is configured to convert the image in the linear domain into an image in the angular domain at the eye window 612 of NED 600 for direct observation by the user's eye (not shown) at the eye window 612. The term "image in the angular domain" refers to the image in which the individual pixels of the image are represented by the angle of the collimated beam at the eye window 612. For example, first pixel 601 emits a first diverging cone 661 collimated by lens 100 into a first collimated beam 671, which has an oblique angle of incidence at the exit pupil 650 of NED 600 located in the eye window 612. Second pixel 602 emits a second diverging cone 662 collimated by lens 100 into a second collimated beam 672, which has a zero (or normal) angle of incidence at the exit pupil 650. Finally, the third pixel 603 emits a third diverging cone 663 collimated by lens 100 into a third collimated beam 673, which has an angle of incidence at the exit pupil 650 with the opposite sign to that of the first collimated beam 671. In other words, lens 100 operates as an angle element to convert the deflection of the diverging beam upstream of lens 100 into the angle of the collimated beam downstream of lens 100.
[0042] Referring to FIG. 7, the near-eye display 700 includes a frame 701 having the external dimensions of a pair of eyeglasses. The frame 701 supports for each eyeball: an electronic display panel 708, an eye lens 710 optically coupled to the electronic display panel 708, an eye-tracking camera 704, and a plurality of illuminators 706. The eye lens 710 may include any of the adjustable lenses disclosed herein. The illuminators 706 may be supported by the eye lens 710 to illuminate the eye window 712. The electronic display panel 708 provides an image in the linear domain, which is converted by the eye lens 710 into an image in the angular domain for the user's eye to observe.
[0043] The purpose of the eye-tracking camera 704 is to determine the position and / or orientation of the user's two eyeballs. Once the position and orientation of the user's eyeballs are known, the gaze convergence distance and direction can be determined. The image displayed on the display panel 708 can be dynamically adjusted to take into account the user's gaze, for better fidelity in immersing the user in the displayed augmented reality scene, and / or to provide specific functions for interaction with augmented reality. The focal length of the eye lens 710 can be tuned to reduce convergence and divergence conflicts, reducing fatigue and headaches for users of the near-eye display 700. In operation, the illuminator 706 illuminates the eyeball at the corresponding eye window 712 so that the eye-tracking camera 704 can acquire an image of the eyeball and provide a reference reflection, i.e., a flash. The flash can act as a reference point in capturing the image of the eyeball, thereby facilitating the determination of the gaze direction by determining the position of the pupil image relative to the flash image. To avoid distracting the user with illumination, the latter can be made invisible to the user. For example, infrared light can be used to illuminate the eye window 712.
[0044] Referring to Figure 8, the HMD 800 is an example of an AR / VR wearable display system that encloses the user's face for maximum immersion in the AR / VR environment. The HMD 800 can generate full virtual 3D images. The HMD 800 may include a front body 802 and a strap 804. The front body 802 is positioned reliably and comfortably in front of the user's eyes, and the strap 804 can be stretched to secure the front body 802 to the user's head. A display system 880 may be placed in the front body 802 to present AR / VR images to the user. The display system 880 may include any of the adjustable lenses disclosed herein. The side 806 of the front body 802 may be opaque or transparent.
[0045] In some specific embodiments, the front body 802 includes a positioner 808 for tracking acceleration of the HMD 800 and an inertial measurement unit (IMU) 810, and a position sensor 812 for tracking the position of the HMD 800. The IMU 810 is an electronic device that generates data indicating the position of the HMD 800 based on measurement signals received from one or more of the position sensors 812, which generate one or more measurement signals in response to movement of the HMD 800. Examples of position sensors 812 include: one or more accelerometers, one or more gyroscopes, one or more magnetometers, another suitable type of sensor for detecting movement, a type of sensor for error correction of the IMU 810, or a combination thereof. The position sensor 812 may be located outside the IMU 810, inside the IMU 810, or a combination thereof.
[0046] The locator 808 is tracked by an external imaging device of the virtual reality system, enabling the virtual reality system to track the position and orientation of the entire HMD 800. Information generated by the IMU 810 and position sensor 812 can be compared with the position and orientation obtained by tracking the locator 808 to improve the tracking accuracy of the HMD 800's position and orientation. Accurate position and orientation are crucial for presenting appropriate virtual scenes to the user when they move and rotate in 3D space.
[0047] The HMD 800 may further include a depth camera assembly (DCA) 811, which captures data describing depth information surrounding some or all of local areas of the HMD 800. For better accuracy in determining the position and orientation of the HMD 800 in 3D space, the depth information may be compared with information from the IMU 810.
[0048] The HMD 800 may further include an eye-tracking system 814 for real-time determination of the orientation and position of the user's eyes. The obtained position and orientation of the eyes also allow the HMD 800 to determine the user's gaze direction and adjust the image generated by the display system 880 accordingly. In one specific example, convergence, i.e., the angle of convergence of the user's gaze, is determined. The determined gaze direction and convergence angle can be used to adjust the focal length of the lens of the display system 880 to reduce convergence-accommodation conflict. Direction and convergence can also be used to compensate for visual artifacts in real time, depending on the viewing angle and eye position. In addition, the determined convergence and gaze angle can be used for user interaction, highlighting objects, bringing objects to the foreground, generating additional objects or indicators, etc. The audio system may also provide, for example, a smaller speaker set built into the front body 802.
[0049] Specific examples of the present invention may include artificial reality systems, or may be implemented in combination with artificial reality systems. Before being presented to a user, the artificial reality system adjusts sensory information about the external world obtained through sensing, such as visual information, audio, tactile (hyaluronic) information, acceleration, balance, etc., in a certain way. By way of non-limiting examples, artificial reality may include virtual reality (VR), augmented reality (AR), mixed reality (MR), mixed reality, or a combination and / or derivative thereof. Artificial reality content may include fully generated content or generated content combined with captured (e.g., real-world) content. Artificial reality content may include visual, audio, bodily or haptic feedback, or a combination thereof. Any of this content may be presented in a single channel or in multiple channels, such as in stereoscopic video that creates a three-dimensional effect for the viewer. Furthermore, in some specific examples, artificial reality may also be associated with applications, products, accessories, services, or a combination thereof used, for example, to create content in artificial reality and / or otherwise used in artificial reality (e.g., to perform activities in artificial reality). Artificial reality systems that deliver artificial reality content can be implemented on a variety of platforms, including wearable displays such as HMDs connected to host computer systems, stand-alone HMDs, near-eye displays with the appearance size of glasses, mobile devices or computing systems, or any other hardware platform capable of delivering artificial reality content to one or more viewers.
[0050] The scope of this invention is not limited to the specific examples described herein. In fact, various other examples and modifications, besides those described herein, will be apparent to those skilled in the art from the foregoing description and accompanying drawings. Therefore, such other examples and modifications are intended to fall within the scope of this invention. Furthermore, although the invention has been described herein in the context of specific embodiments in specific environments for specific purposes, those skilled in the art will recognize that its effectiveness is not limited thereto, and that the invention can be advantageously practiced in any number of environments for any number of purposes. Therefore, the claims set forth below should be interpreted in light of the full scope and spirit of the invention as described herein. [Simplified Explanation of the Diagram]
[0009] Exemplary specific examples will be described in conjunction with the figures, wherein: [Fig. 1A] is a side cross-sectional view of the adjustable lens of the present invention; [Fig. 1B] is a polarization diagram of the adjustable lens of Fig. 1A; [Fig. 1C] is a ray tracing diagram of the adjustable lens of Fig. 1A having a non-curved deformable reflective polarizer; [Fig. 1D] is a ray tracing diagram of the adjustable lens of Fig. 1A having a curved deformable reflective polarizer; [Fig. 2A] is a side cross-sectional view of a deformable reflector in an undeformed state according to a specific example; [Fig. 2B] is a side cross-sectional view of the deformable reflector of Fig. 2A deformed by applying radial pressure; [Fig. 3A] is a side cross-sectional view of a deformable reflector in an undeformed state according to a specific example; [Fig. 3B] is a side cross-sectional view of the deformable reflector of Fig. 3A deformed by applying pressure parallel to the optical axis; [Fig. 4] is a side cross-sectional view of a deformable reflector having an electroactive material layer. [Figure 5A] is a three-dimensional cut view of a deformable reflector having two electroactive layers; [Figure 5B] is an enlarged view of Figure 5A; [Figure 6] is a schematic diagram of a near-eye display including the adjustable lenses of Figures 1A to 1D used as eye lenses for near-eye displays; [Figure 7] is a top view of the near-eye display of the present invention having the appearance size of a pair of glasses; and [Figure 8] is a three-dimensional view of the head-mounted display of the present invention.
Claims
1. A lens comprising: a first reflector and a second reflector opposite to each other; wherein the first reflector is configured to at least partially transmit a light beam passing through it to illuminate the second reflector; wherein the second reflector is configured to at least partially reflect the light beam propagating via the first reflector back to the first reflector; wherein the first reflector is further configured to at least partially reflect the light beam reflected by the second reflector back to the second reflector; wherein the second reflector is further configured to at least partially transmit the light beam reflected by the first reflector; and wherein at least one of the first reflector or the second reflector can be deformed by applying a control signal for tuning the optical power of the lens.
2. The lens of claim 1, wherein the first reflector comprises a partial reflector.
3. The lens as requested in claim 2, wherein the reflector portion is a 50 / 50 mirror.
4. The lens of claim 2, wherein the second reflector includes a reflective polarizer, and the lens further includes a quarter-wave plate located between the first reflector and the second reflector for converting the polarization state of the beam from a first polarization state to a second orthogonal polarization state after the beam has traveled through the quarter-wave plate in a two-way propagation.
5. The lens of claim 4, wherein the reflective polarizer is a linear reflective polarizer.
6. The lens of claim 1, wherein at least one of the first reflector or the second reflector comprises a flexible membrane.
7. The lens of claim 6, wherein the flexible membrane can be deformed by applying a radial force to the periphery of the flexible membrane.
8. The lens of claim 6 further includes a support ring disposed in concentric contact with the flexible membrane, the support ring having a diameter smaller than the diameter of the flexible membrane, wherein the flexible membrane can be deformed by applying a force component to the periphery of the flexible membrane to press the flexible membrane against the support ring, wherein the force component is parallel to the optical axis of the lens.
9. The lens of claim 6, wherein the flexible film comprises an electroactive material layer.
10. The lens of claim 9, wherein the first reflector or the second reflector, at least one of them, further comprises a transparent electrode layer and a conductive reflective layer, wherein the electroactive material layer is disposed between the transparent electrode layer and the conductive reflective layer.
11. The lens of claim 1, wherein both the first reflector and the second reflector can be deformed by applying a control signal to tune the optical power of the lens.
12. The lens of claim 1, further comprising a first refractive lens element located between the first reflector and the second reflector.
13. The lens of claim 12, further comprising a second refractive lens element connected in series with the first refractive lens element located between the first reflector and the second reflector.
14. A near-eye display (NED) comprising: a display panel for providing an image in a linear domain; and an adjustable eyepiece for converting the image in the linear domain into an image in an angular domain at an eye window of the NED, the adjustable eyepiece comprising opposing first and second reflectors; wherein the first reflector is configured to at least partially transmit a light beam passing through it to illuminate the second reflector; wherein the second reflector is configured to at least partially reflect the light beam propagating via the first reflector back to the first reflector; wherein the first reflector is further configured to at least partially reflect the light beam reflected by the second reflector back to the second reflector; wherein the second reflector is further configured to at least partially transmit the light beam reflected by the first reflector; and wherein at least one of the first or second reflector can be deformed by applying a control signal for tuning the adjustable eyepiece.
15. The near-eye display of claim 14, wherein the first reflector includes a partial mirror, and wherein the second reflector includes a linear reflective polarizer, the adjustable eyepiece further including a quarter-wave plate located between the first reflector and the second reflector for converting the polarization state of the beam from a first polarization state to a second orthogonal polarization state after the beam has traveled through the quarter-wave plate in a two-way propagation.
16. The near-eye display of claim 14, wherein at least one of the first reflector or the second reflector comprises a flexible membrane, wherein at least one of the following: the flexible membrane is deformable by applying a radial force to the periphery of the flexible membrane; or the adjustable eyepiece further comprises a support ring disposed in concentric contact with the flexible membrane, the support ring having a diameter smaller than the diameter of the flexible membrane, wherein the flexible membrane is deformable by applying a force component to the periphery of the flexible membrane to press the flexible membrane against the support ring, wherein the force component is parallel to the optical axis of the adjustable eyepiece.
17. The near-eye display of claim 14, wherein at least one of the first reflector or the second reflector comprises a flexible film, the flexible film being disposed in a stacked manner and comprising: a transparent electrode layer; an electroactive material layer; and a conductive reflective layer; wherein the electroactive material layer is disposed between the transparent electrode layer and the conductive reflective layer.
18. A disc lens comprising: a partial reflector; a linear reflective polarizer; and a quarter-wave plate located in an optical path between the partial reflector and the linear reflective polarizer; wherein at least one of the partial reflector or the linear reflective polarizer is curved; and wherein at least one of the partial reflector or the linear reflective polarizer includes a flexible film that can be deformed by applying a control signal for tuning the optical power of the disc lens.
19. The disc lens of claim 18, wherein at least one of the following is true: the flexible membrane can be deformed by applying a radial force to the periphery of the flexible membrane; or the disc lens further includes a support ring disposed in concentric contact with the flexible membrane, the support ring having a diameter smaller than the diameter of the flexible membrane, wherein the flexible membrane can be deformed by applying a force component to the periphery of the flexible membrane to press the flexible membrane against the support ring, wherein the force component is parallel to the optical axis of the disc lens.
20. The disc lens of claim 18, wherein the flexible film is disposed in a stacked manner and includes: a transparent electrode layer; an electroactive material layer; and a conductive reflective layer; wherein the electroactive material layer is disposed between the transparent electrode layer and the conductive reflective layer.