Display System

Abstract

A display system includes a polarization beamsplitter, a first quarter-wave plate, a first reflective element, a second quarter-wave plate, a second reflective element, a polarizer, a half-wave plate, a first waveguide combiner, and a second waveguide combiner. The first waveguide combiner includes a first polarization-sensitive input grating and a first output grating. The second waveguide combiner includes a second polarization-sensitive input grating and a second output grating. The second polarization-sensitive input grating overlaps with the first polarization-sensitive input grating and is closer to a fourth side of the polarization beamsplitter than the first polarization-sensitive input grating, such that a first beam having a first type of polarization passes through the second polarization-sensitive input grating before being incident on the first polarization-sensitive input grating with the first type of polarization.

Description

[0001] This application is a divisional application of patent application No. 202180069337.6 entitled "Optical System and Display Engine for Augmented Reality and Near-Eye Head-Mounted Devices", which was filed on October 12, 2021, with international application number PCT / US2021 / 054516 and entered the Chinese national phase on April 10, 2023. Technical Field

[0002] This invention relates to an optical display engine for a display, such as a light-emitting display, including LED (light-emitting diode) displays, including micro-LED displays, OLED displays, and micro-OLED displays. More specifically, this invention relates to an optical display engine for light-emitting displays (e.g., LED displays, quantum dot displays, thin-film electroluminescent (TEEL) displays, plasma displays, etc.) or transmissive displays (e.g., liquid crystal displays (LCDs), etc.); for example, micro-LED displays that can be used in applications include, but are not limited to, projectors, head-up displays, and augmented reality (AR), mixed reality (MR), and virtual reality (VR) systems or devices (such as headsets or other near-eye devices or systems). Background Technology

[0003] AR imaging typically involves overlaying synthetic images (e.g., digital data, digital content media, or computer-generated images (e.g., 3D images)) onto what a user is seeing in the real world. Because AR images are usually projected onto a single plane for the user to view, while the real-world image the user naturally sees appears on a continuous plane, a mismatch often exists between the synthetic and real-world images. Consequently, the eye must adjust between the two viewing angles, which can lead to visual fatigue over time, for example, fatigue due to visual convergence-accommodation conflict (VAC). Increasing the size of the AR system to improve VAC may not be feasible. A typical AR headset is a device worn around the face or head. To generate AR images, the headset must house many components, such as displays (including stereoscopic displays), optical components (e.g., optical display engines), and power supplies. Therefore, AR headsets can be bulky and large in size. Increasing the size or volume of the AR system or device to address VAC fatigue may not improve VAC and may also reduce the optical power of existing components. Summary of the Invention

[0004] This disclosure provides a display system comprising: a polarization beamsplitter positioned to receive one or more light beams from a display device via a third side of the polarization beamsplitter, wherein the display device emits at least one unpolarized light beam; a first quarter-wave plate positioned outside a first side of the polarization beamsplitter; a first reflective element positioned adjacent to the first quarter-wave plate; a second quarter-wave plate positioned outside a second side of the polarization beamsplitter; a second reflective element positioned adjacent to the second quarter-wave plate; a polarizer positioned between the display device and the polarization beamsplitter, wherein the unpolarized light beam becomes a polarized light beam when passing through the polarizer; and a half-wave plate positioned between the polarizer and the polarization beamsplitter, the half-wave plate being used to polarize the light beams. The polarization of the polarized beam is rotated before it is received by the polarization beam splitter; a first waveguide combiner includes a first polarization-sensitive input grating and a first output grating, the first polarization-sensitive input grating being used to receive a first beam of a first type polarization emitted from a first optical path via a fourth side of the polarization beam splitter, and to propagate the first beam of the first type polarization toward the first output grating in a first direction; and a second waveguide combiner includes a second polarization-sensitive input grating and a second output grating, the second polarization-sensitive input grating being used to receive a second beam of a second type polarization emitted from a second optical path via a fourth side of the polarization beam splitter, and to propagate the second beam of the second type polarization toward the second output grating in a first direction. The second polarization-sensitive input grating overlaps with the first polarization-sensitive input grating and is closer to the fourth side of the polarization beam splitter than the first polarization-sensitive input grating, such that the first beam of the first type polarization passes through the second polarization-sensitive input grating before being incident on the first polarization-sensitive input grating with the first type polarization. Attached Figure Description

[0005] The present disclosure is illustrated and described herein with reference to various accompanying drawings, in which similar reference numerals are appropriately used to denote similar system components, and in the drawings:

[0006] Figure 1 An optical system for providing a separated optical path for unpolarized light according to an embodiment of the present invention is shown;

[0007] Figure 2 An optical system for providing a separated optical path for selectively polarized light according to an embodiment of the present invention is shown;

[0008] Figure 3 This illustrates portions of an image, according to an embodiment of the present invention, which are transmitted through separate optical paths and incident on different observation planes;

[0009] Figure 4A and Figure 4BA half-wave plate (HWP) configuration for routing portions of an image to separate observation planes is shown according to an embodiment of the present invention.

[0010] Figure 5 An optical system for providing separate optical paths pointing to the left and right eyes, according to an embodiment of the present invention, is shown;

[0011] Figure 6 An optical system including a waveguide combiner according to an embodiment of the present invention is shown;

[0012] Figure 7 A schematic diagram of an optical system for displaying images on different viewing planes according to an embodiment of the present invention is shown;

[0013] Figures 8A to 8C The projection of image portions with different resolutions according to an embodiment of the present invention is shown.

[0014] Figures 9A to 9B Approximate dimensions of an optical system according to an embodiment of the present invention are shown.

[0015] Figure 9C Approximate dimensions of the optical system based on the comparative example are shown. Detailed Implementation

[0016] The exemplary embodiments described herein provide an optical system and an optical display engine that separates or divides electromagnetic radiation (e.g., light) output from a spatial light modulator or display into beams of different polarizations, and provides a separate optical path for each beam of different polarizations, such that the recombined beams can be routed to, transmitted to, or received by or incident on different observation planes. The components of the optical display engine described herein are arranged to maximize the brightness and / or optical power from a finite-brightness display such as a micro-LED. Furthermore, the disclosed embodiments reduce the size and / or improve the efficiency of a display system or device that integrates, includes, or couples (physically and / or electrically) a display (e.g., an LED display, such as a micro-LED display and / or an OLED display) into such a system or device. For the purposes of this disclosure, an LED display is used as an example to describe the invention. However, the invention is applicable to any type, shape, and / or size of light-emitting display, and this will be apparent to those skilled in the art. Embodiments of the present invention can receive unpolarized or linearly polarized light and route light components of different polarizations into separate optical paths via novel arrangements or combinations of optical components (e.g., polarization beam splitters (PBS), quarter-wave plates (QWP), and reflective components such as mirrors or reflecting lenses).

[0017] Embodiments of the present invention project different images or portions of images onto different viewing planes by means of separate optical paths associated with different types of polarization. This may be desirable in AR head-mounted devices to project more realistic synthetic images (e.g., computer-generated images or computer-generated 3D images) and improve user comfort.

[0018] Embodiments of the present invention project (or display) images or portions of images at different resolutions, enabling the display of a large composite field of view (FOV) at high apparent resolution from a single small and efficient display.

[0019] A display system according to the present invention includes a polarization beam splitter (PBS), a first quarter-wave plate (QWP) positioned outside a first side of the PBS, a first reflective element positioned adjacent to the first QWP, a second QWP positioned outside a second side of the PBS, and a second reflective element positioned adjacent to the second QWP. A first optical path for a first type of polarization is generated by a combination of at least the PBS, the first QWP, and the first reflective element, and a second optical path for a second type of polarization is generated by a combination of at least the PBS, the second QWP, and the second reflective element. In embodiments of the invention, the PBS is positioned to receive one or more light beams from a display device via a third side, and to output one or more light beams traversing the first and second optical paths to one or more viewing planes via a fourth side. In some embodiments of the invention, the display device includes one or more of a light-emitting diode (LED), a micro-LED, an organic LED (OLED), a micro-OLED, or a liquid crystal display (LCD). In embodiments of the invention, the display device emits at least one unpolarized light beam. The PBS splits an unpolarized light beam into a first optical component with a first type of polarization and a second optical component with a second type of polarization. The first optical component is reflected into a first optical path to reach a first QWP and a first reflecting element, while the second optical component is transmitted into a second optical path to reach a second QWP and a second reflecting element. In an embodiment of the invention, as the first and second optical components travel along the first and second optical paths respectively, the polarization of each of the first and second optical components is reversed. For example, the first optical component is s-polarized (also called σ-polarized or transverse electric field (TE)) when it enters the PBS, and becomes p-polarized (also called π-polarized or transverse magnetic field (TM)) after entering the first optical path, passing through the first QWP to reach the first reflecting element, being reflected by the first reflecting element, and returning through the first QWP to enter the PBS. The PBS causes the first optical component to transmit through a fourth side. Furthermore, the second light component is p-polarized when it enters the PBS, and becomes s-polarized after entering the second optical path, passing through the second QWP to reach the second reflective element, being reflected by the second reflective element, and returning through the second QWP to enter the PBS, wherein the PBS causes the second light component to be transmitted through the fourth side.

[0020] In another embodiment of the invention described herein, the display system further includes: a polarizer positioned between the display device and the PBS, wherein an unpolarized beam becomes a polarized beam as it passes through the polarizer; and a half-wave plate (HWP) positioned between the polarizer and the PBS, wherein the HWP rotates the polarization of the polarized beam such that the polarized beam is guided into one of a first optical path or a second optical path depending on the polarization rotation. For example, the polarized beam is s-polarized when it enters the PBS, and becomes p-polarized after entering the first optical path, passing through the first QWP to a first reflective element, being reflected by the first reflective element, and returning through the first QWP to enter the PBS. For example, the polarized beam is p-polarized when it enters the PBS, and becomes s-polarized after entering the second optical path, passing through the second QWP to a second reflective element, being reflected by the second reflective element, and returning through the second QWP to enter the PBS. In one embodiment of the invention, the HWP includes a controllable HWP, and the HWP is coupled to a controller that determines how the controllable HWP rotates the polarization of the polarized beam. The controllable HWP rotates the polarization of different polarized beams at different specific times. In another embodiment of the invention, the HWP includes an addressable HWP, which further includes a plurality of independently controlled elements, each of which rotates the polarization of a polarized beam. Individual portions of the plurality of independently controlled elements rotate the polarization of different beams associated with individual image portions. In some embodiments of the invention, the addressable HWP includes one or more of a spatial light modulator or a transmissive spatial light modulator.

[0021] In another embodiment of the invention described herein, one or more beams output via the fourth side of the PBS are incident on one or more input gratings. For example, one or more input gratings include polarization-sensitive input gratings, wherein a first beam with a second type of polarization exiting from a first optical path is incident on the first input grating, and wherein a second beam with a first type of polarization exiting from a second optical path is incident on a second input grating. In some embodiments of the invention, one or more input gratings include electrically switchable input gratings. In some embodiments of the invention, each of one or more input gratings is coupled to a waveguide combiner. For example, an exemplary optical system may also include a waveguide grating or output grating coupled to a waveguide combiner, wherein one or more beams propagate along the waveguide combiner until reaching the output grating and are thereby guided to a corresponding observation plane. Differences between observation planes can be generated by using different combinations of components or optical parameters (e.g., mirror shape, waveguide characteristics, refractive elements, etc.) in the two optical paths. Alternatively or additionally, the output grating itself may have different amounts of optical power encoded therein, such that the two optical paths are optically identical, and the difference in viewing plane distance is generated by the output grating itself. One or more beams may correspond to a composite image, and wherein the output grating guides the composite image to the eye, so that the eye perceives both the composite image and reality simultaneously, thereby generating an augmented reality (AR) image in which the composite image appears as if it were combined with and / or superimposed on the real-world scene within the viewer's field of view (FOV). In embodiments of the invention, the waveguide combiner may include holographic polymer-dispersed liquid crystal (HPDLC). The invention is not limited to HPDLC-type waveguide combiners, and virtually any polarization-selective grating may be used.

[0022] Detailed embodiments are disclosed herein as needed. It must be understood that the disclosed embodiments are merely examples of various and alternative forms. As used herein, the term "exemplary" is broadly used to refer to embodiments used as illustrations, samples, models, or patterns. The drawings are not necessarily drawn to scale, and some features may be enlarged or reduced to show details of specific components. In other instances, well-known components, systems, materials, or methods known to those skilled in the art have not been described in detail to avoid obscuring the content of this disclosure. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but rather as a representative basis for the claims and for teaching those skilled in the art.

[0023] In the following detailed description, reference is made to the accompanying drawings, which form part of this detailed description and illustrate, by way of illustration, possible embodiments. It should be understood that other embodiments may be utilized, and structural or logical changes may be made without departing from the scope. Therefore, the following detailed description should not be construed as limiting, and the scope of the embodiments is defined by the appended claims and their equivalents.

[0024] Descriptions may use perspective-based descriptions, such as up / down, back / front, and top / bottom. Such descriptions are for facilitating discussion only and are not intended to limit the application of the disclosed embodiments. The terms “coupled” and “connected” and their derivatives (e.g., “communically coupled”) may be used. It should be understood that these terms are not intended to be synonyms with each other. Rather, in a particular embodiment, “connected” may be used to indicate that two or more elements are in direct physical contact with each other. “Coupled” can mean that two or more elements are in direct physical contact. However, “coupled” can also mean that two or more elements are not in direct contact with each other but still cooperate or interact with each other, such as when two or more elements are optically coupled (i.e., where electromagnetic radiation, such as light, is transmitted or directed between parts, elements, and / or planes in space (along a path known in some cases as an optical path)) or electrically coupled via, for example, a wired or wireless connection. For descriptive purposes, phrases of the form “A / B,” “A or B,” or “A and / or B” mean (A), (B), or (A and B). For the purposes of description, the phrase in the form "at least one of A, B, and C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C). For the purposes of description, the phrase in the form "(A)B" means (B) or (AB), that is, A is an optional element.

[0025] The description may use the terms "implementation" or "various implementations," both of which may refer to one or more of the same or different implementations. Furthermore, the terms "comprising," "comprise," "including," "having," etc., used with respect to implementations are synonymous and are generally intended as "open-ended" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "at least having," the term "include" should be interpreted as "including but not limited to," etc.). Regarding the use of any plural and / or singular terms herein, those skilled in the art may appropriately convert from plural to singular and / or from singular to plural depending on the context and / or application. For clarity, various singular / plural arrangements may be explicitly stated herein.

[0026] Various embodiments will now be described with reference to the accompanying drawings, wherein similar reference numerals are always used to refer to similar elements. In the following description, numerous specific details are set forth for illustrative purposes to facilitate a thorough understanding of one or more embodiments. However, in some or all instances, it will be apparent that any of the embodiments described below can be practiced without employing the specific design details described below.

[0027] Figure 1 An embodiment of the present invention of an optical display system is illustrated, the optical display system including an optical display engine 100 and a display 110. The optical display engine 100 may include a polarization beam splitter (PBS) 101 (in the illustrated example, including two separate halves 101a, 101b and an interface 101c therebetween), at least two quarter-wave plates (QWPs) 102, 104, and at least two reflective elements 103, 105. The interface 101c is not a separate component, but rather the location where one of the halves meets the other. However, in some implementations, additional components such as coatings, gratings, films, and / or adhesives may be disposed along the interface 101c. In one embodiment of the invention, at least two QWPs 102, 104 are placed or located outside the PBS 101. In one embodiment of the invention, a first QWP 102 is placed or located on a first side of the PBS 101 (e.g., Figure 1 The first QWP 102 is placed or located between the PBS 101 and the first reflective element 103, outside the top side of the PBS 101. In an embodiment of the invention, the second QWP 104 is placed or located outside the second side of the PBS 101 (the side opposite to the side facing the display device 110). In an embodiment of the invention, the second QWP 104 is placed or located between the PBS 101 and the second reflective element 105. Figure 1 In the embodiment shown, at least two QWPs 102, 104 and at least two reflective elements 103, 105 are placed or located outside the PBS 101 and along adjacent sides of the PBS 101 such that the first QWP 102 and the second QWP 104 form right angles to each other.

[0028] In embodiments of the invention, QWPs 102, 104 may be laminated, coupled, or attached to PBS 101. In embodiments of the invention, reflective elements 103, 105 may include curved mirrors or reflective lenses, which, for a given curvature, may impart greater optical power and less dispersion relative to a refractive lens.

[0029] In operation, the display device 110 according to the invention (e.g., an unpolarized display, such as a micro-LED display without a polarizer or polarizing film) generates or outputs an image in the form of an unpolarized beam 107 directed at the PBS 101. In embodiments of the invention, the display 110 may be, for example, an LED display, including but not limited to micro-LED displays and OLED displays. The PBS 101 polarizes the unpolarized beam 107 by transmitting incident light having an electric field parallel to the plane of incidence (p-polarized) and reflecting light having an electric field perpendicular to the plane (s-polarized). For example, the electric field of s-polarized light oscillates along the z-axis, while the electric field of p-polarized light oscillates in the xy-plane. In embodiments of the invention, the PBS 101 divides the unpolarized light into a first light component reflected along a first optical path 108 (also referred to as "path 1") and a second light component transmitted along a second optical path 109 (also referred to as "path 2"). For example, the PBS 101 may be formed by joining or coupling two halves 101a, 101b (e.g., two prisms), thereby creating an interface 101c between the two halves. In some embodiments of the invention, PBS 101 may be a single device or structure (e.g., formed by molding or other patterning methods), thereby selecting the material for each of the two halves 101a, 101b such that p-polarized light is transmitted through interface 101c and s-polarized light is reflected by interface 101c. In one embodiment of the invention, one or more of the two halves 101a, 101b of PBS 101 may be coated on the side of the two halves 101a, 101b facing the other half of the two halves 101a, 101b (i.e., coated at the location where the two halves 101a, 101b meet or abut each other, or coated at the interface 101c of the two halves 101a, 101b). In another embodiment of the invention, PBS 101 may include a grating or film at the interface 101c of the two halves 101a, 101b. A grating or film at interface 101c can be formed by patterning one or both surfaces of the two halves 101a, 101b and / or by providing one or more material layers between the two halves 101a, 101b. The dimensions of the coating and / or grating or film are designed such that p-polarized light is transmitted while s-polarized light is reflected, or vice versa.

[0030] Furthermore, in the example operation, when the unpolarized beam 107 is initially received (i.e., the beam 107 passes through PBS 101 for the first time), PBS 101 causes the s-polarized light to be reflected along the first path 108 until the polarization of the s-polarized light is changed to p-polarized light by the first QWP 102 before it passes through PBS 101 for the second time. Additionally, when the unpolarized beam 107 is initially received (i.e., the beam 107 passes through PBS 101 for the first time), PBS 101 causes the p-polarized light component to be transmitted along the second path 109 until the polarization of the p-polarized light component is changed to s-polarized light by the second QWP 104 before it passes through PBS 101 for the second time. In both of the current paths (i.e., optical paths 108 and 109), the light travels through PBS 101, and at least two QWPs 102 and 104 are oriented such that each of QWPs 102 and 104 causes the polarization of the p-polarized and s-polarized light components to change from linearly polarized light to circularly polarized light (i.e., from linear polarization to circular polarization) upon first passing through at least two QWPs 102 and 104. This can be achieved, for example, by orienting at least QWPs 102 and 104 such that their respective fast axes are oriented at a 45-degree angle relative to the polarization direction of the incident linearly polarized light.

[0031] One or more reflecting elements 103, 105 respectively apply optical power and change the polarization directionality (e.g., left-handed to right-handed, or vice versa, right-handed to left-handed) of the polarized light components traveling along each optical path. The light components, now with different polarization directions, then pass through each of QWP 102, QWP 104 a second time. During this second pass, each of QWP 102, QWP 104 converts the light component traveling along the first path 108 and the second path 109 back to linear polarization, but due to the change in directionality, converts it to an orientation orthogonal to the orientation of each of the light components during the first pass through QWP 102, 104. Therefore, each light component exits from the exit surface of PBS 101 (e.g., as shown in the image). Figure 1 (The bottom surface of the PBS 101 shown) is emitted. Although Figure 1 For illustrative purposes, the emitted light component corresponding to the first path 108 and the emitted light component corresponding to the second path 109 are shown as laterally separated, but in actual implementation, the emitted light components can be combined (i.e., substantially coaxial).

[0032] In embodiments of the invention, the reflective elements 103, 105 may be, for example, reflective lenses, mirrors with curvature, deformable mirrors, movable mirrors, or substrates with reflective surfaces or properties. In embodiments of the invention, at least two reflective elements 103, 105 are located at the same distance from the PBS 101. Those skilled in the art will understand that a mirror is any reflective lens or device. Thus, light components (i.e., the s-polarized light components and p-polarized light components corresponding to the respective portions of the image displayed by the display device 110) are reflected away from the corresponding reflective elements 103, 105 and combined in the PBS 101. In other words, the original unpolarized light beam 107 is initially split into two polarized light components when it first passes through the PBS 101, each light component traversing separate optical paths 108, 109, and then the light components are recombined in the PBS 101 during the second passage through the PBS 101. Unlike known related technologies, this exemplary configuration achieves these effects in a compact system because, for example, the separation and subsequent recombination of unpolarized light in PBS101 reduces the spatial volume of the optical display engine 100 and eliminates or minimizes the need for a brighter display (as would be the case in a system with only a single optical path), which might be necessary in existing systems.

[0033] Furthermore, in embodiments of the present invention, one or more refractive lenses 111, 112, 113, 114 can be combined with... Figure 1In the optical system of the present invention, a micro-LED display 110 is placed in front of or to one side of a first refractive lens 111, and such a refractive lens 111, for example, focuses the light beam transmitted from the display 110 (when the refractive lens 111 is placed, the light from the display 110 is transmitted directly when it reaches the position of the refractive lens 111 before reaching the PBS 101, and / or when the refractive lens 111 is placed, the light from the display 110 is transmitted time-grounded when it reaches the position of the refractive lens 111 after reaching the PBS 101). In the embodiment of the present invention, the PBS 101 is placed after the first refractive lens 111, such that the light transmitted from the display 110 travels directly or indirectly (e.g., when another element or optical component is placed in the optical path after the refractive lens 111 but before the PBS 101) via the refractive lens 111 to the PBS 101. In the embodiment of the present invention, the PBS 101 is placed on or to the other side of the first refractive lens 111 (i.e., on the side opposite to the side facing the display 110). In an embodiment of the invention, a first refractive lens 111 is placed outside or located on a first side of the PBS 101, and a second refractive lens 112 is placed outside or located on a second side of the PBS 101. In an embodiment of the invention, the second refractive lens 112 is placed outside or located on a side of the PBS 101 perpendicular to the side of the PBS 101 where the first refractive lens 111 is located. In an embodiment of the invention, a third refractive lens 113 is placed outside or located on a third side of the PBS 101, and a fourth refractive lens 114 is placed outside or located on a fourth side of the PBS 101. In an embodiment of the invention, the third refractive lens 113 is placed outside or located on a side of the PBS 101 opposite to the side of the PBS 101 where the first refractive lens is located. In an embodiment of the invention, the fourth refractive lens 114 is placed outside or located on a side of the PBS 101 opposite to the side of the PBS 101 where the second refractive lens 112 is located. Those skilled in the art will understand from this disclosure that the use of one, some, or all of the refractive lenses 111 to 114 is optional, depending on whether and to what extent a particular component of light is modified (e.g., refracted, shaped, etc.), and that the optical power and effects achieved by the optical display engine 100 are attributable to the reflective elements 103, 105.

[0034] In embodiments of the invention, refractive lenses 111 to 114 and reflective elements 103 and 105 together form an eyepiece or optical assembly that presents the image generated by the display 110 to the observer. Although in Figure 1The refractive and reflective elements are depicted as single components, but those skilled in the art will understand that they can: 1) be decomposed into multiple elements at various locations to reduce optical aberrations; or 2) be implemented by one or more components (optical or otherwise). The reflective elements 103, 105 have a large optical power with virtually no dispersion relative to the refractive lenses, and thus the use of one or more such reflective lenses enables compact systems (e.g., display systems). The change in polarization rotation during reflection, combined with the operation of QWPs 102, 104, makes it possible to achieve efficient and compact systems. According to... Figure 1 In the implementation of the display system, splitting the light corresponding to the image into light components with opposite polarization and recombining the light components can achieve the advantages of reduced engine size or increased light efficiency.

[0035] Figure 2 An optical system for providing separate optical paths for different polarized light is illustrated according to an embodiment of the invention. In this embodiment, an unpolarized beam emitted from a display device 210 is linearly polarized by a polarizer 215, and the polarization is rotated and / or controlled by a half-wave plate (HWP) 217. Thus, the unpolarized beam becomes a polarized beam 207 after passing through the polarizer 215, and when the polarized beam 207 reaches the HWP 217, the HWP 217 rotates the polarization of the beam, causing the polarized beam to be guided into one of a first optical path 208 or a second optical path 209 depending on the rotation of the polarization. For example, if HWP 217 is controlled to rotate polarized beam 207 so that polarized beam 207 is s-polarized when it enters display engine 200, then when s-polarized beam 207 travels through display engine 200, s-polarized beam 207 becomes p-polarized because it travels along first optical path 208, passes through first QWP 202 to reach first reflective element 203, is reflected by first reflective element 203, and returns to pass through first QWP 202 and enters PBS 201.

[0036] Conversely, when HWP 217 rotates the polarized beam 207 so that the polarized beam 207 is p-polarized upon entering the display engine, then as the p-polarized beam 207 travels through the display engine 200, it becomes s-polarized because it travels along the second optical path 209, passes through the second QWP 204 to reach the second reflective element 205, is reflected by the second reflective element 205, and returns through the second QWP 204 and enters the PBS 201. The two light components (e.g., the separated beams traversing optical paths 208, 209) are combined in the PBS 201 and emitted from the bottom side of the PBS 201 (where "bottom side" refers to...). Figure 2 (as shown in the orientation) is emitted. Although Figure 2For illustrative purposes, the emitted light component corresponding to the first path 208 and the emitted light component corresponding to the second path 209 are shown as laterally separated, but in actual implementation, the emitted light components can be combined (i.e., substantially coaxial).

[0037] In embodiments of the invention, the position of reflective element 203 relative to QWP 202 differs from the position of reflective element 205 relative to QWP 204. In embodiments of the invention, the curvatures of reflective elements 203 and 205 are different. In one embodiment of the invention, one or more reflective elements 203, 205 may comprise deformable or movable mirrors, enabling control of the viewing distance via changes in the power and / or position of reflective elements 203, 205. In embodiments of the invention, the optical power of reflective elements 203, 205 is changed by deforming the surface, wherein the surface deformation alters the curvature of reflective elements 203, 205 such that during operation, each of the initial p-polarized light component 208 and s-polarized light component 209 is reflected away from the optical elements within the optical display engine 200. These modifications enable the change of focal position and viewing distance (i.e., the perceived distance from the viewer's eye to the viewing plane) of the light corresponding to path 1 and the light corresponding to path 2 via different or variable optical powers and / or positions of reflective elements 203 and 205 (where any of deformation, curvature alteration, and / or position alteration can change the optical power, focal length, and / or viewing distance). Figure 7 (further details are provided below).

[0038] In one embodiment of the invention, HWP 217 includes a controllable HWP and is coupled to a controller (not shown) that determines how the controllable HWP 217 rotates the polarization of the polarized beam 207. The controller may provide a control signal to the controllable HWP 217 that causes the HWP 217 to rotate the polarization of different polarized beams at different specific times. For example, the controllable HWP 217 may include a liquid crystal layer, and the control signal may change the orientation of the liquid crystal in the liquid crystal layer. In another embodiment of the invention, HWP 217 includes an addressable HWP that also includes a plurality of independently controlled polarization elements (which may be referred to as pixels), each of which rotates the polarization of the polarized beam. Individual portions of the plurality of independently controlled elements rotate the polarization of different beams associated with individual image portions. In embodiments of the invention, the addressable HWP 217 includes one or more spatial light modulators or transmissive spatial light modulators, and a control output or signal (e.g., voltage or mechanical output) can cause one or more modulation elements of the spatial light modulator and / or transmissive spatial light modulator to change orientation. See, for example, [link to relevant documentation]. Figure 3 as well as Figure 4A and Figure 4B The images shown are different portions produced by different configurations of controllable HWP and addressable HWP, respectively.

[0039] In embodiments of the invention, HWP 217 (whether controllable or addressable) may be external to optical display engine 200. In embodiments of the invention, HWP 217 may be assembled with display 210 within a package. In embodiments of the invention, polarizer 215 may be external to optical display engine 210. In embodiments of the invention, polarizer 215 may be assembled within a package including display 210. In embodiments of the invention, polarizer 215 may be located between display 210 and HWP 217. In embodiments of the invention, HWP 217 is placed or located between polarizer 215 and refractive lens 211. In embodiments of the invention, controllable HWP 217 may be a device comprising liquid crystal (e.g., liquid crystal cells) between transparent electrodes, the liquid crystal being controlled to change its orientation, thereby imparting a corresponding polarization to light passing through it. In an example, controllable HWP 217 causes polarization rotation of an image / light polarized by polarizer 215, and thereby determines which of the optical paths 208, 209 the polarized beam 207 traverses. In the example, a controllable HWP 217 (e.g., a controller or driver circuit and / or software that modulates the electric field across the electrodes of the controllable HWP 217) is controlled to cause the controllable HWP 217 to rotate the polarization of the polarized beam 207, thereby determining which of the optical paths 208, 209 it follows. In the example, the controllable HWP 217 outputs p-polarized or s-polarized light. In the example, the controllable HWP 217 is set to a position such that p-polarized or s-polarized light is output or transmitted by the controllable HWP 217. In the example, the controllable HWP 217 is used to rotate or pass through a particular polarization image or image portion in a time-divisional manner, thereby causing light to traverse the first optical path 208 or the second optical path 209 in a time-divisional manner (e.g., see...). Figure 3 (As shown in the embodiment). In the example, when the controllable HWP 217 transmits s-polarized light, the beam 207 follows optical path 208. In the example, when the controllable HWP 217 transmits p-polarized light, the beam 207 follows optical path 209.

[0040] In an embodiment of the present invention, via the exit surface of the PBS ( Figure 2One or more light beams output from the bottom surface of the waveguide (208, 209) are incident on one or more input gratings 222, 223. The input gratings couple light passing through optical paths 208, 209 into waveguides 220, 221, respectively. For example, one or more input gratings 222, 223 include polarization-sensitive input gratings, wherein a first light beam with a second type of polarization exiting from the first optical path 208 is incident on the first input grating 222, and wherein a second light beam with a first type of polarization exiting from the second optical path 209 is incident on the second input grating 223. In some examples, one or more input gratings 222, 223 include electrically switchable input gratings and / or polarization-selective gratings, such that incident light is coupled into the corresponding waveguide depending on the state of the switch. In some examples, each of one or more input gratings 222, 223 is located in and / or coupled to waveguide combiners 220, 221, respectively. In addition, the output grating (hereinafter referred to as...) Figure 7 (Discussed in more detail) can be coupled to waveguide combiners 220, 221, wherein one or more beams propagate along the waveguide combiner until reaching the output grating, wherein the output grating combines the synthesized image with reality to generate an augmented reality (AR) image (see, for example) Figure 7 The implementation shown is illustrated.

[0041] In embodiments of the invention, the addressable HWP 217 can be driven, guided, or controlled to output s-polarized light from addressable elements of the addressable HWP 217 (e.g., individual reflective or transmissive elements of modulation elements in an array), and this s-polarized light travels along optical path 208 and transmits, guides, or outputs an image portion to input grating 222. In embodiments of the invention, the addressable HWP 217 can be driven, guided, or controlled to output p-polarized light from addressable elements of the addressable HWP 217, and this p-polarized light travels along optical path 209 and transmits or outputs an image portion to input grating 223. In an example, such as... Figure 4A and Figure 4B As shown, the addressable HWP 217 can be a spatial light modulator. In the example, the addressable HWP 217 can be made or constructed from liquid crystal materials / materials and silicon, such as high-temperature polycrystalline silicon (HTPS). In the example, the addressable HWP 217 can be a transmissive spatial light modulator. Furthermore, the two oppositely polarized portions of the image can be placed at different viewing planes, such as... Figure 7 As shown in the image.

[0042] In embodiments of the invention, light of one polarization (e.g., s-polarization) travels along a different path than light of another polarization (e.g., p-polarization). For example, the first polarized light component travels along optical path 208, while the second polarized light component travels along path 209. In the example, after the first polarized light component is reflected away from the first reflecting element 203 (including a mirror or reflecting lens), the first polarized light component passes through PBS 201 a second time, and after the second polarized light is reflected away from the second reflecting element 205, the second polarized light passes through PBS 201 a second time. In the example, the first polarized light travels along optical path 208 (i.e., path 1) and is incident on input grating 222, and light of a different polarization travels along optical path 209 (i.e., path 2) and is incident on input grating 223. In the example, each of input gratings 222, 223 is located on, coupled to, and / or integrated into waveguide combiners 220, 221. Therefore, after light of the first polarization is incident on input grating 222, the light of the first polarization propagates through waveguide combiner 220. After light of a different or second polarization is incident on input grating 223, the light of a different or second polarization propagates through waveguide combiner 221. In the example, p-polarized light propagates through waveguide combiner 220, and s-polarized light propagates through waveguide combiner 221. In the example, each of waveguide combiners 220, 221 includes or may include, incorporate, or couple to polarization-sensitive input gratings 222, 223. In the example, waveguide combiners 220, 221 may be constructed of phase-separated structures or devices such as holographic polymer-dispersed liquid crystal (HPDLC) media, gratings, matter, or materials. In the example, input gratings 222, 223 couple light beams (e.g., corresponding to an image or image portion received at each of input gratings 222, 223) to the waveguide combiners 220, 221 where input gratings 222, 223 are respectively located. In the example, at least one of the input gratings 222 and 223 can be an electrically switchable grating. In the example, an HPDLC device can be used as an electrically switchable grating. In the example, light emitted from the PBS 201 is demultiplexed via input gratings 222 and 223 based on the polarization of the incident light / image portion. In the example, light directed to each observation plane is coupled into separate waveguides 220 and 221 such that light directed to each plane can be independently manipulated by downstream optics, as described below. Figure 7 Described in more detail. This capability of the invention is advantageous when using known pupil replication techniques to enlarge the eyebox (i.e., the area where the user's eye can see the projected image), because, due to differences in the perceived position of each observation plane, it may be necessary to manipulate or compensate the optical path of each observation plane differently. See, for example, [link to relevant documentation]. Figures 3 to 4A and Figure 4B as well as Figure 7 This shows portions of an image of beams with different polarizations projected onto different viewing planes.

[0043] Figure 3 This illustrates portions of an image, according to an exemplary embodiment, routed by separate optical paths and incident on different viewing planes. As described herein, one or more beams processed by an exemplary optical system (e.g., any optical system according to the embodiments described herein) may correspond to composite images and / or portions of composite images, and such composite images can be combined with reality to generate augmented reality (AR) images. In the embodiment, Figure 3 Image 330 is a composite image projected onto one or more observation planes via one or more optical paths. Figure 3 In the example shown, image 330 is a composite image comprising two composite portions 331 and 332 (i.e., image portions corresponding to a mountain at a distant observation plane and a bird at a close observation plane, respectively). In this example, a controllable HWP can be used to output different image portions 331 and 332 using HWP configuration 334 at different times (e.g., subframes) T=1 and T=2. For example, the light component or beam corresponding to image portion 331 travels along the first optical path and arrives at the first input grating (e.g., at a certain moment or within a certain time period) at a certain moment or within a certain time period. Figure 2 The light component or beam corresponding to image portion 332 travels along the second optical path and reaches or arrives at the second input grating, and is output from the system at different times or within a second time period. These time periods are shorter than the integration time of the human visual system, allowing the observer to perceive the simultaneous existence of two image portions 331 and 332. Therefore, the two image portions 331 and 332 (i.e., the mountain portion and the bird portion) can be transmitted in a time-division manner, and thus appear to the human eye as if they appear in a single image, such as... Figure 3 As shown in the cube, the light is simultaneously incident on different input gratings in different waveguide combiners and thus appears on different observation planes. This is achieved, for example, by encoding different lens parameters in the output grating, changing the focal plane of each image path (e.g., by changing the shape or position of the corresponding reflective element, by using a refractive element, etc.), or by inserting physical lenses between the waveguide combiners.

[0044] Figures 4A to 4B A half-wave plate (HWP) configuration for routing portions of an image to separate observation planes, according to an example embodiment, is shown. As described herein, one or more beams processed by the exemplary optical system may correspond to a synthesized image and / or portions thereof, whereby the synthesized image is combined with reality to generate an augmented reality (AR) image. Therefore, Figure 4A The image 430 is projected onto one or more viewing planes and includes at least two composite portions 431 and 432 (i.e., a mountain and a bird, respectively). In this example, an addressable HWP can be used to output different image portions 431, 432 using an HWP configuration 435 that instructs different elements of the HWP to transmit different beams of light into different optical paths of the exemplary optical display engine. For example, an addressable HWP (e.g., Figure 2 HWP 217 (in the image) includes multiple independently controlled elements, each of which rotates the polarization of a polarized beam. Individual portions of the multiple independently controlled elements rotate the polarization of different beams associated with individual image portions 431, 432. (See reference...) Figure 4B HWP mapping 436 corresponds to HWP setting 434. In some examples, the addressable HWP includes one or more spatial light modulators or transmissive spatial light modulators. In an implementation, the addressable HWP is controlled by a control unit that sets the delay of each pixel element of the addressable HWP to guide the incident beam to path 1 or path 2 (by rotating the polarization). The pixel mapping of the HWP is similar to a binary image. One image value (i.e., the HWP setting) is routed along path 1, while the other image value is routed along path 2.

[0045] Figure 5 An optical system for providing separate optical paths pointing to the left and right eyes, according to an example embodiment, is shown. Figure 5The system shown includes at least an optical display engine 500, a display 510, a polarizer 515, an HWP 517, waveguide combiners 520 and 521, and input gratings 522 and 523. In this example, an unpolarized beam emitted from the display device 510 is linearly polarized by the polarizer 515, and the polarization is rotated and / or controllably selected by the half-wave plate (HWP) 517. Thus, the unpolarized beam becomes a polarized beam 507 as it passes through the polarizer 515 and the HWP 517, wherein the HWP 517 rotates the polarization of the beam, such that the polarized beam is guided, depending on the rotation of polarization, into one of a first optical path 508 or a second optical path 509. For example, polarized beam 507 is s-polarized when it enters PBS 501, and becomes p-polarized after entering the first optical path 508, passing through the first QWP 502 to the first reflective element 503, being reflected by the first reflective element 503, and returning after passing through the first QWP 502 and entering PBS 501. Alternatively or additionally, polarized beam 507 is p-polarized when it enters PBS 501, and becomes s-polarized after entering the second optical path 509, passing through the second QWP 504 to the second reflective element 505, being reflected by the second reflective element 505, and returning after passing through the second QWP 504 and entering PBS 501. The two optical components (e.g., separate beams passing through optical paths 508, 509) are combined in PBS 501 and exit from the bottom side of PBS 501 (where "bottom side" refers to...). Figure 5 (The orientation shown).

[0046] In this example, one or more beams output from the bottom side of PBS 501 are incident on one or more input gratings 522, 523. For example, one or more input gratings 522, 523 include polarization-sensitive input gratings, wherein a first beam with a second type of polarization exiting from a first optical path 508 is incident on the first input grating 522, and wherein a second beam with a first type of polarization exiting from a second optical path 509 is incident on the second input grating 523. In some examples, one or more input gratings 522, 523 include electrically switchable input gratings. In some examples, each of one or more input gratings 522, 523 is coupled to waveguide combiners 520, 521, respectively. Furthermore, the output grating (hereinafter referred to as...) Figure 7 (Discussed in more detail) can be coupled to waveguide combiners 520, 521, wherein one or more beams propagate along the waveguide combiner until they reach an output grating, wherein the output grating combines the synthesized image with reality to generate an augmented reality (AR) image (see, for example...). Figure 7(The implementation shown herein). In this particular example, one waveguide / waveguide combiner 520 is used for the left eye and another waveguide combiner 521 is used for the right eye. This makes it possible to produce a binocular head-mounted device using only a single optical system as shown herein, which uses only one display 510, such as a micro-LED display.

[0047] Figure 6 An optical system including a waveguide combiner according to an embodiment of the present invention is illustrated. In this example, an image in the form of an unpolarized beam 607 generated by a display device 610 (e.g., a micro-LED display device) is received at a polarizer 615 and passes through the polarizer 615, and after such passage, the unpolarized beam 607 becomes polarized. In this example, any number of refractive lenses 611 can focus the unpolarized beam 607 before it passes through the waveguide combiner 620. In this example, the refractive lenses 611 first focus the light that has already passed through the polarizer 615, and then, due to the specific polarization of the input grating 622 relative to the incident light, the focused light passes through the waveguide combiner 620 with minimal interaction with the polarization-sensitive input grating 622. Then, a properly oriented QWP 604 (e.g., a QWP 604 positioned such that its fast axis is at forty-five degrees relative to the polarization direction of the incident beam 607) converts the polarization of the light emitted from the waveguide combiner 620 from linear polarization to circular polarization. Figure 6 In the illustration, the fast axis is located in the same plane as QWP 604 and is therefore not shown separately. In some embodiments, any number of refractive lenses 611, 612 impose optical power on the light, for example, based on the shape and / or material of the refractive lenses 611, 612. In embodiments, a reflecting element 605 (e.g., a reflecting lens or a curved mirror) imposes optical power based on the curvature of the reflecting element 605 and alters the directionality of the polarization of the polarized beam transmitted from QWP 604 to the reflecting element 605 and received by the reflecting element 605 from QWP 604. In an example, the light reflected from the reflecting element 605 passes through QWP 604 (and optionally, the refractive lens 612) a second time, and QWP 604 converts the light back to linear polarization, the converted linear polarization having an orientation orthogonal to the orientation of the beam 607 when it passes through the input grating 622 during its first pass. Then, the input grating 622 will optically couple or guide the beam received at the input grating 622 from the reflective element 605 into the waveguide combiner 620.

[0048] Figure 7 A schematic diagram of an optical system for displaying images on different viewing planes according to an example embodiment is shown, thereby illustrating the behavior of light downstream of an optical display engine. In this example, it includes, for example... Figure 1 , Figure 2 , Figure 5 and Figure 6 The optical display engine 700 of the components shown can operate in conjunction with, for example, a display 710 (which may include an LED display, a micro-LED display, an OLED display, a micro-OLED display, etc.). Some or all of the components of the optical display engine 700 can be coupled to, integrated with, and / or assembled with the display 710, such that images are generated, such as composite images (e.g., computer-generated images or images created as overlays of real-world scenes or images, such as...). Figure 3 (As shown in Figures 4 to 4). The input grating 722 receives one or more beams corresponding to the synthesized image (and / or portions of the image) and couples them into the waveguide combiner 720. The one or more beams then propagate along the waveguide combiner 720 until they reach the output grating 724, which combines the synthesized image with reality (i.e., a real-world scene or image), enabling the desired AR image or portion of the image (e.g., a synthesized image combined with reality or a real image) to be presented to the eye 740.

[0049] In embodiments of the present invention, according to the disclosed embodiments (e.g., such as...) Figure 1 , Figure 2 , Figure 5 and Figure 6 The display system described herein includes a controllable or addressable HWP that guides s-polarized and p-polarized light along different paths by means of specific control applied to the HWP, directing two or more oppositely polarized light beams corresponding to different image portions to different observation planes 741, 742. For example, s-polarized light is guided to one of the observation planes 741, 742, and p-polarized light is guided to the other of the observation planes 741, 742. Those skilled in the art will understand that the observation planes 741, 742 can be spatial or optical planes, devices and / or substrates (e.g., planes on which real, virtual, enhanced, or other images are placed, presented, or positioned).

[0050] In some examples, one or more reflective elements within the optical display engine 700 may include deformable or movable mirrors, enabling control of the viewing distance via changes in the mirror's power and / or position. In one example, the angle of the reflective element is changed by deforming the surface and altering its curvature, such that during operation, each of the initial p-polarized and s-polarized light portions reflects away from the optical elements within the optical display engine 700. This allows control of the viewing distance (i.e., the distance from the viewer's eye 740 to the viewing planes 741, 742) via changes in the power and / or position of the reflective element, reducing mismatch between the synthesized image and the real-world image and enabling mitigation of VAC (Vibration Variability and Distress).

[0051] In some exemplary implementations, the perceived resolution of the display (e.g., an AR display incorporating the example optical display engine described herein or a near-eye display) can be dynamically changed using time-multiplexing techniques. For example, refer to Figures 8A to 8C According to the present invention, an optical system that provides different optical paths for different polarized light, such as the one described above, is used. Figure 1 , Figure 2 , Figure 5 , Figure 6 and / or Figure 7 Those optical systems enable or demonstrate an increase in the perceived resolution of the display. For example, according to embodiments of the invention, a high-resolution image or image portion 832 (via path 2 of the exemplary optical display engine described herein) is displayed at a location corresponding to the portion of the viewer's FOV defined by the fovea of ​​the retina, while a lower-resolution image or image portion 831 (via path 1 of the exemplary optical display engine described herein) is displayed at a portion of the viewer's FOV surrounding the fovea of ​​the retina. Those skilled in the art generally understand that human visual acuity is very high only over a narrow FOV defined by the fovea of ​​the retina (i.e., retinal resolution). Therefore, a system according to any of the embodiments mentioned above can be used to project images of different resolutions from a single display unit as a desired composite image 830 onto the viewing plane. For example, when using a controllable HWP, an image or image portion of a first resolution (e.g., one of image portions 831, 832) is projected at a first moment or time period (T=1), and a second image or image portion of a second resolution (e.g., one of image portions 831, 832) is projected at a second moment or time period (T=2). In the example, during the same frame, a controllable HWP is used to project an image or image portion of a first resolution at a first moment (or within a first time period) and a second image or image portion at a second moment (or within a second time period). In the example, the first image or image portion travels along path 1, and the second image or image portion travels along path 2.

[0052] By directing or generating high-resolution images onto the display only for the portion of the image that the viewer can see at high resolution, large, high-resolution fields of view (FOV) can be simulated using small, lower-resolution, more energy-efficient displays. For example... Figure 8AAs shown, light traveling along path 1 projects or generates a first image or image portion 831 (i.e., a low-resolution image, region, or image portion represented by an "x" or "diamond" hash pattern) from a display (e.g., a microdisplay) with low angular resolution across a wide FOV (and the region or central area of ​​the high-resolution image that the human eye 840 can distinguish or perceive is left blank). Conversely, light traveling along path 2 projects or generates a second image or image portion 832 (i.e., a high-resolution or higher-resolution image, region, or image portion represented by a "square" pattern) from a display (e.g., a microdisplay) with much higher angular resolution across a narrow central FOV. These projected regions form the peripheral region (i.e., the shaded low-resolution "x" or "diamond" region) and the central concave region (i.e., the "square" high-resolution region) of the image seen by the eye 840. In this example, the display system switches between outputting or generating low-resolution and high-resolution images faster than the user can perceive, ensuring that the user will perceive a single image at retinal resolution or higher across the entire FOV.

[0053] Those skilled in the art may also assume that people try to keep their eyes in a centered and relaxed position to avoid muscle tension. Therefore, in some examples, the higher resolution area can be fixed to the center of the FOV so that the image or image portion 832 (e.g., the higher resolution area, image, or image portion) is naturally aligned with the user's fovea, such as... Figure 8B As shown. Alternative locations or others, such as Figure 8C As shown, some examples can utilize deformable and / or movable reflective elements 803 to move a high-resolution area (including image portion 832) around the user's field of view (FOV). Figure 8C The image shows a portion of the optical system, including PBS 801, QWP 802, and a portion of reflective element 803. This corresponds to the above regarding... Figure 2 and / or Figure 7 Any of the optical systems described, for example Figure 2 PBS 201, second QWP 204, and second reflective element 205; and / or Figure 7 The optical display engine 700. In Figure 8C In configuration (1), the reflective element 803 is not tilted or deformed, and therefore the image or image portion 832 is located at the center of the composite image 830. Figure 8C In configuration (2), the reflective element 803 is tilted or deformed in a first direction, and therefore the image or image portion 832 is located in the upper region of the composite image 830. Figure 8CIn configuration (3), the reflective element 803 is tilted or deformed in a second direction opposite to the first direction, and thus the image or image portion 832 is located in the lower region of the composite image 830.

[0054] In this example, the region, image, or image portion can be moved to any combination of locations in the x, y, and z planes, and is not limited to movement in the vertical direction. When combined with eye-tracking sensors and related technologies, a system configured with movable and / or deformable reflective elements 803 can move the image, region, or image portion (e.g., high-resolution region, image, or image portion 832) to align with the user's gaze. Therefore, a large FOV image with high perceived resolution can be created using a single, relatively low-resolution microdisplay. The lower-resolution microdisplay results in a smaller, lower-cost, and more energy-efficient system.

[0055] Figures 9A to 9B Approximate dimensions of an optical system according to an example embodiment are shown. These figures depict different embodiments (e.g., Figure 2 and Figure 6 Approximate dimensions of the implementation method. Figure 9C Approximate dimensions of the optical system according to the comparative example are shown. For comparison, the display system shown in these figures includes a 0.37” color-micro LED 910 display with a resolution of 2720 × 1530 (Bayer pattern), a pixel pitch of 3.015 μm, a display space f / # of 2, a FOV of 40°, and an exit pupil diameter of 6 mm. Figure 9A An optical display engine 901 is shown, coupled to reflective elements 903 and 905, a display 910, and a refractive lens 911. The optical display engine 901 is also coupled to an input grating 922 and a waveguide combiner 920. This embodiment corresponds to, for example... Figure 2 The optical system shown. Figure 9B An optical display engine 905 and a display 910, further coupled to the input grating 922 and the waveguide combiner 920, are shown, corresponding to Figure 6 The optical system shown. Figure 9C A comparative system is shown with a display coupled to an input grating and a waveguide combiner, but without an optical engine disposed therebetween. Those skilled in the art will understand that these dimensions are exemplary and that different components and applications will result in different dimensions. All examples are similar and function as expected for AR systems when image quality is taken into account. However, Figure 9A and Figure 9B The systems shown (corresponding to respectively) Figure 2 and Figure 6The exemplary optical system results in a significant reduction in size and shape factor compared to a standalone refractive optical system. When compared by volume, Figure 9A and Figure 9B The system (i.e., the system according to the example implementation) has respectively Figure 9C The system volume (i.e., the system according to the comparative example) is 50% and 25% of the total volume. Additionally, the system's folded optical path and orientation (e.g., as...) Figure 1 , Figure 2 , Figure 5 , Figure 6 and Figures 9A to 9B (As shown) This allows for improved industrial design and heat dissipation in top-mounted AR systems because the main body of the optical engine can be oriented upwards and away from the user's face, and the main heat source (display) can be placed or located on the top side of the system to allow for better natural convection.

[0056] In the examples, in any of the embodiments mentioned above, the HWP may include a switchable HWP with a pre-polarizer, such as a 38 mm × 35.5 mm × 1.4 mm BVO (Boulder Vision Optik) (RTM) Pi-cell. In the examples, in any of the embodiments mentioned above, the PBS may include a 15 mm × 15 mm × 15 mm Colorlink (RTM) film PBS. In the examples, in any of the embodiments mentioned above, the QWP may include a Colorlink (RTM) QWG with a 138 nm delay. In the examples, in any of the embodiments mentioned above, the reflective element may include a concave mirror with a 15 mm focal length, such as Edmund Optics (RTM) part number 46-234. In the examples, in any of the embodiments mentioned above, the reflective element can be mounted on a translation stage, wherein there is a translation of 0.5 mm between the infinity focal point and the 18” distance focal point. In the examples, in any of the embodiments mentioned above, one or more axes of motion of the reflective element can be realized by miniaturized voice coils or piezoelectric actuators, and deformation can be realized by using a piezoelectric film on a glass film on a polymer substrate or by utilizing a microelectromechanical system (MENS) structure under the surface of a thin mirror.

[0057] The operation of the optical display engine 100 and / or display device 110 may be controlled by one or more processors not shown herein, but should be understood to be incorporated by those skilled in the art based on this disclosure. In exemplary embodiments, one or more processors may include a GPU (“Graphics Processing Unit”), a SoC (“System-on-Chip”), a CPU (“Central Processing Unit”), a DSP (“Digital Signal Processor”), an ASIC (“Application-Specific Integrated Circuit”), etc. Furthermore, additional components not shown herein will be conceived by those skilled in the art based on this disclosure. For example, a sensor data acquisition module for acquiring, receiving, and / or storing sensor data acquired from various sensors such as inertial measurement sensors, ambient light sensors, temperature sensors, image sensors, and / or eye-tracking sensors. These are specific illustrative and non-exhaustive examples of sensors, and other sensors may also be used.

[0058] The aspects of the subject matter described herein can be implemented in digital electronic circuits or in computer software, firmware, or hardware—including the structural devices and their structural equivalents disclosed in this specification—or in combination thereof. The subject matter described herein can be implemented in special-purpose logic circuits such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits).

[0059] It should be understood that the disclosed subject matter, in its application, is not limited to the construction details and arrangement of components set forth in the following description or shown in the accompanying drawings. The disclosed subject matter can have other embodiments and can be practiced and performed in various ways. Furthermore, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be construed as limiting. Therefore, those skilled in the art will recognize that the concepts upon which this disclosure is based can readily be used as the basis for designing other structures, methods, and systems for performing several purposes of the disclosed subject matter. Therefore, it is important that the claims be considered to include such equivalent structures without departing from the spirit and scope of the disclosed subject matter.

[0060] Although the disclosed subject matter has been described and illustrated in the above exemplary embodiments, it should be understood that this disclosure has been made by way of example only, and many changes may be made to the details of the implementation of the disclosed subject matter without departing from the spirit and scope of the disclosed subject matter, which is limited only by the appended claims.

[0061] In addition, this technology can also be configured as follows.

[0062] (1) A display system, comprising:

[0063] Polarizing beam splitter (PBS);

[0064] The first quarter-wave plate (QWP) is positioned outside the first side of the PBS.

[0065] Positioned adjacent to the first reflective element of the first QWP;

[0066] The second QWP is located outside the second side of the PBS; and

[0067] Positioned adjacent to the second reflective element of the second QWP,

[0068] Specifically, a first optical path for a first type of polarization is generated by combining the PBS, the first QWP, and the first reflective element, and a second optical path for a second type of polarization is generated by combining the PBS, the second QWP, and the second reflective element.

[0069] (2) The display system according to (1), wherein the PBS is positioned to receive one or more light beams from the display device via a third side and to output the one or more light beams passing through the first optical path and the second optical path to one or more observation planes via a fourth side.

[0070] (3) The display system according to (2), wherein the display device includes one or more of a light-emitting diode (LED), a micro LED, an organic LED (OLED), a micro OLED, and a liquid crystal display (LCD).

[0071] (4) The display system according to (2), wherein the display device emits at least one unpolarized light beam.

[0072] (5) The display system according to (4), wherein the PBS splits the unpolarized beam into a first light component having the first type of polarization and a second light component having the second type of polarization, reflects the first light component into the first optical path to reach the first QWP and the first reflective element, and transmits the second light component into the second optical path to reach the second QWP and the second reflective element.

[0073] (6) The display system according to (5), wherein when the first light component and the second light component travel along the first optical path and the second optical path respectively, the polarization of each of the first light component and the second light component is reversed.

[0074] (7) The display system according to (6), wherein:

[0075] The first light component is s-polarized when it enters the PBS, and becomes p-polarized after entering the first optical path, passing through the first QWP to the first reflective element, being reflected by the first reflective element, and returning through the first QWP to enter the PBS, wherein the PBS allows the first beam to be transmitted through the fourth side; and

[0076] The second light component is p-polarized when it enters the PBS, and becomes s-polarized after entering the second optical path, passing through the second QWP to the second reflective element, being reflected by the second reflective element, and returning through the second QWP to enter the PBS, wherein the PBS allows the second beam to be transmitted through the fourth side.

[0077] (8) The display system according to (4) further includes:

[0078] A polarizer positioned between the display device and the PBS, wherein the unpolarized light beam becomes a polarized light beam as it passes through the polarizer; and

[0079] A half-wave plate (HWP) is positioned between the polarizer and the PBS, wherein the HWP rotates the polarization of the polarized beam.

[0080] The polarized beam is guided into one of the first optical path or the second optical path depending on the rotation of the polarization.

[0081] (9) The display system according to (8), wherein the polarized beam is s-polarized when it enters the PBS and becomes p-polarized after entering the first optical path, passing through the first QWP to the first reflective element, being reflected by the first reflective element, and returning through the first QWP to enter the PBS.

[0082] (10) The display system according to (8), wherein the polarized beam is p-polarized when it enters the PBS and becomes s-polarized after entering the second optical path, passing through the second QWP to the second reflective element, being reflected by the second reflective element, and returning through the second QWP to enter the PBS.

[0083] (11) The display system according to (8), wherein the HWP includes a controllable HWP and the HWP is coupled to a controller that determines how the controllable HWP causes the polarization rotation of the polarized beam.

[0084] (12) The display system according to (11), wherein the controllable HWP rotates the polarization of different polarized beams at different specific times.

[0085] (13) The display system according to (8), wherein the HWP includes an addressable HWP, the addressable HWP further including a plurality of independently controlled elements, wherein each of the independently controlled elements causes polarization rotation of the polarized beam.

[0086] (14) The display system according to (13), wherein individual portions of the plurality of independently controlled elements cause polarization rotation of different light beams associated with individual image portions.

[0087] (15) The display system according to (14), wherein the addressable HWP includes one or more of a spatial light modulator or a transmissive spatial light modulator.

[0088] (16) The display system according to (2), wherein the one or more light beams output via the fourth side of the PBS are incident on one or more input gratings.

[0089] (17) The display system according to (16), wherein:

[0090] The one or more input gratings include polarization-sensitive input gratings.

[0091] A first beam of the second type of polarization emitted from the first optical path is incident on the first input grating, and

[0092] A second beam with the first type of polarization emitted from the second optical path is incident on the second input grating.

[0093] (18) The display system according to (17), wherein the one or more input gratings comprise electrically switchable input gratings.

[0094] (19) The display system according to (16), wherein each of the one or more input gratings is coupled to a waveguide combiner.

[0095] (20) The display system according to (19) further includes an output grating coupled to the waveguide combiner, wherein the one or more beams propagate along the waveguide combiner until they reach the output grating.

[0096] (21) The display system according to (20), wherein:

[0097] The one or more beams correspond to the synthesized image, and

[0098] The output grating combines the synthesized image with reality to generate an augmented reality (AR) image.

[0099] (22) The display system according to (19), wherein the input grating and / or the output grating comprises holographic polymer dispersed liquid crystal (HPDLC).

[0100] (23) The display system according to (1), wherein each of the first reflective element and the second reflective element includes at least one of a mirror, a deformable mirror or a movable mirror.

[0101] (24) An optical display engine, comprising:

[0102] A polarization beam splitter (PBS) includes at least four sides, wherein a first side is positioned to receive one or more beams from a display device, and a second side is positioned to output the one or more beams to one or more observation planes;

[0103] A first quarter-wave plate (QWP) and a first reflecting element are positioned outside the third side of the PBS opposite to the second side, wherein a first optical path is created for a first light component having a first polarization in one or more light beams, and wherein the first polarization is reversed when the first light component traverses the first optical path and exits from the second side of the PBS; and

[0104] A second QWP and a second reflective element are positioned outside the fourth side of the PBS opposite to the first side, wherein a second optical path is created for a second light component with a second polarization in one or more light beams, and wherein the second polarization is reversed when the second light component passes through the second optical path and exits from the second side of the PBS.

[0105] (25) The optical display engine according to (24), wherein the display device emits at least one unpolarized light beam.

[0106] (26) The optical display engine according to (25), wherein the PBS splits the unpolarized beam into a first light component having the first polarization and a second light component having the second polarization, reflects the first light component into the first optical path to reach the first QWP and the first reflective element, and transmits the second light component into the second optical path to reach the second QWP and the second reflective element.

[0107] (27) The optical display engine according to (26), wherein when the first light component and the second light component travel along the first optical path and the second optical path respectively, the polarization of each of the first light component and the second light component is reversed.

[0108] (28) The optical display engine according to (27), wherein:

[0109] The first beam is s-polarized when it enters the PBS, and becomes p-polarized after entering the first optical path, passing through the first QWP to the first reflective element, being reflected by the first reflective element, and returning through the first QWP to enter the PBS, wherein the PBS allows the first beam to be transmitted through the fourth side; and

[0110] The second beam is p-polarized when it enters the PBS, and becomes s-polarized after entering the second optical path, passing through the second QWP to the second reflective element, being reflected by the second reflective element, and returning through the second QWP to enter the PBS, wherein the PBS allows the second beam to be transmitted through the fourth side.

[0111] (29) The optical display engine according to (25) further includes:

[0112] A polarizer positioned between the display device and the PBS, wherein the unpolarized light beam becomes a polarized light beam as it passes through the polarizer; and

[0113] A half-wave plate (HWP) is positioned between the polarizer and the PBS, wherein the HWP rotates the polarization of the polarized beam.

[0114] The polarized beam is guided into one of the first optical path or the second optical path depending on the rotation of the polarization.

[0115] (30) The optical display engine according to (29), wherein the polarized beam is s-polarized when it enters the PBS and becomes p-polarized after entering the first optical path, passing through the first QWP to the first reflective element, being reflected by the first reflective element, and returning through the first QWP to enter the PBS.

[0116] (31) The optical display engine according to (29), wherein the polarized beam is p-polarized when it enters the PBS, and becomes s-polarized after entering the second optical path, passing through the second QWP to the second reflective element, being reflected by the second reflective element, and returning through the second QWP to enter the PBS.

[0117] (32) The optical display engine according to (29), wherein the HWP includes a controllable HWP and the HWP is coupled to a controller that determines how the controllable HWP causes the polarization rotation of the polarized beam.

[0118] (33) The optical display engine according to (32), wherein the controllable HWP rotates the polarization of different polarized beams at different specific times.

[0119] (34) The optical display engine according to (29), wherein the HWP includes an addressable HWP, the addressable HWP further including a plurality of independently controlled elements, wherein each of the independently controlled elements causes polarization rotation of the polarized beam.

[0120] (35) The optical display engine according to (34), wherein individual portions of the plurality of independently controlled elements cause polarization rotation of different light beams associated with individual image portions.

[0121] (36) The optical display engine according to (35), wherein the addressable HWP includes one or more of a spatial light modulator or a transmissive spatial light modulator.

[0122] (37) The optical display engine according to (24), wherein the one or more beams output via the fourth side of the PBS are incident on one or more input gratings.

[0123] (38) The optical display engine according to (37), wherein:

[0124] The one or more input gratings include polarization-sensitive input gratings.

[0125] The first beam with the second type of polarization emitted from the first optical path is incident on the first input grating, and

[0126] A second beam with the first type of polarization emitted from the second optical path is incident on the second input grating.

[0127] (39) The optical display engine according to (38), wherein the one or more input gratings include electrically switchable input gratings.

[0128] (40) The optical display engine according to (38), wherein each of the one or more input gratings is coupled to a waveguide combiner.

[0129] (41) The optical display engine according to (40) further includes an output grating coupled to the waveguide combiner, wherein the one or more beams propagate along the waveguide combiner until they reach the output grating.

[0130] (42) The optical display engine according to (41), wherein the one or more light beams correspond to a composite image, and wherein the output grating combines the composite image with reality to generate an augmented reality (AR) image.

Claims

1. A display system, comprising: A polarization beam splitter, the polarization beam splitter being positioned to receive one or more beams from a display device via a third side of the polarization beam splitter, wherein the display device emits at least one unpolarized beam; The first quarter-wave plate is positioned outside the first side of the polarization beam splitter; The first reflecting element is positioned adjacent to the first quarter-wave plate; The second quarter-wave plate is positioned outside the second side of the polarization beam splitter; The second reflecting element is positioned adjacent to the second quarter-wave plate; A polarizer positioned between the display device and the polarizing beam splitter, wherein an unpolarized light beam becomes a polarized light beam as it passes through the polarizer; and A half-wave plate positioned between the polarizer and the polarization beam splitter, the half-wave plate being used to rotate the polarization of the polarization beam before it is received by the polarization beam splitter; A first waveguide combiner, comprising a first polarization-sensitive input grating and a first output grating, wherein the first polarization-sensitive input grating is used to receive a first beam of a first type of polarization emitted from a first optical path via a fourth side of the polarization beam splitter, and to propagate the first beam of the first type of polarization toward the first output grating in a first direction; and The second waveguide combiner includes a second polarization-sensitive input grating and a second output grating. The second polarization-sensitive input grating is used to receive a second beam of second polarization emitted from the second optical path via the fourth side of the polarization beam splitter, and to propagate the second beam of second polarization toward the second output grating in the first direction. The second polarization-sensitive input grating overlaps with the first polarization-sensitive input grating and is closer to the fourth side of the polarization beam splitter than the first polarization-sensitive input grating, such that the first beam having the first type of polarization passes through the second polarization-sensitive input grating before being incident on the first polarization-sensitive input grating with the first type of polarization.

2. The display system according to claim 1, wherein, The first beam corresponds to a first image portion of the synthesized image, and the second beam corresponds to a second image portion of the synthesized image, and the first output grating and the second output grating combine the synthesized image with reality to generate an augmented reality (AR) image.

3. The display system according to claim 2, wherein, The first polarization-sensitive input grating receives the first beam at a first time, and the second polarization-sensitive input grating receives the second beam at a second time, different from the first time.

4. The display system according to claim 2, wherein, The first output grating guides the first beam to a first observation plane at a first observation distance, and the second output grating guides the second beam to a second observation plane at a second observation distance different from the first observation distance.

5. The display system according to claim 2, wherein, The second image portion has a resolution greater than that of the first image portion.

6. The display system according to claim 5, wherein, The second image portion corresponds to the portion of the viewer's field of view defined by the fovea region of the viewer's retina, and the first image portion corresponds to the portion of the viewer's field of view surrounding the fovea region.

7. The display system according to claim 5, wherein, The second reflective element is tiltable, and the position of the second image portion in the composite image can be adjusted based on the tilt of the second reflective element.

8. The display system according to claim 1, wherein, The polarization beam splitter splits one or more light beams into a first light component having the first type of polarization and a second light component having the second type of polarization, reflects the first light component into the first optical path to reach the first quarter-wave plate and the first reflective element, and transmits the second light component into the second optical path to reach the second quarter-wave plate and the second reflective element.

9. The display system according to claim 8, wherein, When the first light component travels along the first optical path, the polarization of the first light component is reversed, and when the second light component travels along the second optical path, the polarization of the second light component is reversed.

10. The display system according to claim 9, wherein: The first light component is s-polarized when it enters the polarizing beam splitter, and becomes p-polarized after entering the first optical path, passing through the first quarter-wave plate to the first reflecting element, being reflected by the first reflecting element, and returning through the first quarter-wave plate to enter the polarizing beam splitter. The polarizing beam splitter allows the first light component to be transmitted through the fourth side; and The second light component is p-polarized when it enters the polarizing beam splitter, and becomes s-polarized after entering the second optical path, passing through the second quarter-wave plate to the second reflecting element, being reflected by the second reflecting element, and returning through the second quarter-wave plate to enter the polarizing beam splitter, which allows the second light component to be transmitted through the fourth side.

11. The display system according to claim 1, wherein, The polarized beam includes a first polarized beam that is s-polarized when it first enters the polarization beam splitter, and becomes p-polarized after entering the first optical path, passing through the first quarter-wave plate to the first reflecting element, being reflected by the first reflecting element, and returning through the first quarter-wave plate to enter the polarization beam splitter. The polarized beam also includes a second polarized beam that is p-polarized when it re-enters the polarization beam splitter, and becomes s-polarized after entering the second optical path, passing through the second quarter-wave plate to the second reflecting element, being reflected by the second reflecting element, and returning through the second quarter-wave plate to enter the polarization beam splitter.

12. The display system according to claim 1, wherein, The first quarter-wave plate is attached to the first side of the polarization beam splitter, and the second quarter-wave plate is attached to the second side of the polarization beam splitter.

13. The display system according to claim 1, wherein, The first reflecting element is a first distance away from the first side of the polarization beam splitter, and the second reflecting element is a second distance away from the second side of the polarization beam splitter, the second distance being the same as the first distance.

14. The display system according to claim 1, further comprising a plurality of refractive lenses, the plurality of refractive lenses comprising at least one of the following: A first refractive lens is disposed between the display device and the third side of the polarizing beam splitter; A second refractive lens is disposed between the first quarter-wave plate and the first reflective element; A third refractive lens is disposed between the second quarter-wave plate and the second reflective element; and A fourth refractive lens is disposed on the fourth side of the polarizing beam splitter.

15. The display system according to claim 1, wherein, The half-wave plate includes a controllable half-wave plate, and the display system further includes: A controller coupled to the controllable half-wave plate, the controller being configured to determine how the controllable half-wave plate causes the polarization rotation of the polarized beam, and to output a control signal to the controllable half-wave plate according to the determination, the control signal causing the half-wave plate to cause the polarization rotation of the polarized beam.

16. The display system according to claim 15, wherein, The controllable half-wave plate includes a liquid crystal layer, the liquid crystal layer includes liquid crystal, and the control signal changes the orientation of the liquid crystal.

17. The display system according to claim 1, wherein, The half-wave plate includes an addressable half-wave plate, which includes a plurality of independently controlled optical modulators, each of which is used to rotate the polarization of the polarized beam. In this context, individual portions of the plurality of independently controlled optical modulators cause polarization rotation of different light beams associated with individual image portions.

18. The display system according to claim 1, wherein, The first polarization-sensitive input grating and the second polarization-sensitive input grating are electrically switchable input gratings.

Images