Optical imaging systems, optical microstructures, and head-mounted display devices

Abstract

This application provides an optical imaging system, an optical microstructure, and a head-mounted display device. The optical imaging system includes a display screen and a reflective polarizer, and further includes: an optical structure layer comprising multiple optical microstructures arranged in parallel. Each optical microstructure includes a first coupling structure, a second coupling structure, a microcavity, and a coupling-out structure. The first coupling structure couples first circularly polarized light from one side of the display screen into the microcavity. The microcavity transmits the first circularly polarized light to the coupling-out structure, which couples the first circularly polarized light out and directs it toward the reflective polarizer. The second coupling structure couples first circularly polarized light from one side of the reflective polarizer into the microcavity. The microcavity also converts the first circularly polarized light from the second coupling structure into second circularly polarized light. The coupling-out structure further couples the second circularly polarized light out and directs it toward the reflective polarizer. The optical imaging system of this application has advantages such as low cost and ease of implementation.

Description

Technical Field

[0001] This application relates to the field of optical technology, and in particular to an optical imaging system, optical microstructure, and head-mounted display device. Background Technology

[0002] With the development of near-eye display technology, head-mounted devices (HMDs) are widely used in work, life, and entertainment. The most critical component in an HMD is the optical imaging system. To reduce the size of the optical imaging system, an ultra-short focal length optical folding path (pancake) scheme can be adopted. This scheme achieves a thinner and lighter design of the imaging system by using light reflection and changes in the polarization state of light.

[0003] The related technology provides an optical imaging system that achieves light transmission and reflection by setting a magnetic response layer (MRL) between the display screen and the reflective polarizer (RF). That is, the MRL transmits forward visible light from front to back and reflects backward visible light from back to front, thereby reducing light intensity loss while realizing optical path folding.

[0004] However, MRLs are expensive to produce, have stringent environmental requirements, and require strong magnetic fields, which can cause magnetic interference to other electronic components within the HMD. These factors significantly reduce the usability of MRL-based optical imaging systems and make implementation difficult. Therefore, providing a low-cost and easily implemented optical imaging system has become a pressing technical problem. Summary of the Invention

[0005] This application provides an optical imaging system, an optical microstructure, and a head-mounted display device. The optical imaging system of this application realizes the transmission and reflection of light by setting a microcavity-based optical structure layer, which has the advantages of low cost and easy implementation.

[0006] In a first aspect, an optical imaging system is provided, including a display screen and a reflective polarizer, and further comprising: an optical structure layer located between the display screen and the reflective polarizer, the optical structure layer including a plurality of optical microstructures arranged in parallel, the optical microstructures including a first coupling structure, a second coupling structure, a microcavity, and a coupling-out structure; the first coupling structure is used to couple first circularly polarized light from one side of the display screen into the microcavity, the microcavity is used to transmit the first circularly polarized light to the coupling-out structure, the coupling-out structure is used to couple the first circularly polarized light out and direct it toward the reflective polarizer; the second coupling structure is used to couple the first circularly polarized light from one side of the reflective polarizer into the microcavity, the microcavity is also used to convert the first circularly polarized light from the second coupling structure into second circularly polarized light, the coupling-out structure is also used to couple the second circularly polarized light out and direct it toward the reflective polarizer.

[0007] The optical imaging system provided in this application includes a display screen, an optical structure layer, and a reflective polarizer arranged sequentially. The optical structure layer includes multiple optical microstructures arranged in parallel, including microcavities, enabling the microstructures to transmit first circularly polarized light from one side of the display screen and reflect first circularly polarized light from the other side of the reflective polarizer, converting it into second circularly polarized light. This allows the optical structure layer to achieve light transmission and reflection, breaking the forward and reverse time-reversal symmetry of the light field. Compared to the MRL scheme in related technologies, the optical structure layer in this application is a purely passive hardware structure layer that does not require external field driving. It has no special requirements for the materials used, is easy to manufacture, has a simple production process, and can reuse the optical path design of other existing parts. The system assembly steps are no different from those of a normal optical module. These reasons give the optical imaging system provided in this application advantages such as low cost and ease of implementation, which is conducive to the large-scale promotion and application of the product.

[0008] Furthermore, compared to the 50 / 50 beam splitter (semi-transparent and semi-reflective film) scheme in related technologies, the optical imaging system provided in this application embodiment loses 50% of the light intensity in the initial polarization stage, and there is no further light intensity loss in subsequent processes. That is, the setting of the optical structure layer will not cause additional light intensity loss, which is equivalent to the light intensity of the optical imaging system provided in this application embodiment of the related technology being nearly four times higher.

[0009] Optionally, the microcavity in the embodiments of this application can be a microcavity structure based on the whispering gallery mode, in which the first circularly polarized light can be transmitted through total internal reflection.

[0010] Optionally, the microcavity in the embodiments of this application may include a single microcavity or may be formed by multiple microcavities occasionally interacting with each other.

[0011] Optionally, in the embodiments of this application, the first circularly polarized light can be left-handed circularly polarized light, and the second circularly polarized light can be right-handed circularly polarized light. Alternatively, the first circularly polarized light can also be right-handed circularly polarized light, and the second circularly polarized light can be left-handed circularly polarized light.

[0012] In one possible implementation, the first coupling structure includes a first coupling lens and a first coupling waveguide, the light-incident surface of the first coupling lens facing the display screen, and the first coupling lens being connected to the microcavity via the first coupling waveguide.

[0013] The above settings help simplify the structural design of optical microstructures, reduce the difficulty of processing, and facilitate the coupling of the first circularly polarized light from one side of the display screen into the optical microstructure.

[0014] In one possible implementation, the coupling structure includes a coupling lens and a coupling waveguide, the light-emitting surface of the coupling lens facing the reflective polarizer, and the coupling lens being connected to the microcavity via the coupling waveguide.

[0015] The above settings help simplify the structural design of optical microstructures, reduce the difficulty of processing, and allow transmitted and reflected light to share the same coupling structure, making it convenient for transmitted and reflected light to be directed toward the reflective polarizer.

[0016] In one possible implementation, the second coupling structure includes a second coupling lens and a second coupling waveguide, the incident surface of the second coupling lens facing the reflective polarizer, and the second coupling lens being connected to the microcavity via the second coupling waveguide.

[0017] The above settings help simplify the structural design of optical microstructures, reduce the processing difficulty, and facilitate the coupling of the first circularly polarized light from one side of the reflective polarizer into the optical microstructure.

[0018] In one possible implementation, the optical imaging system further includes an imaging lens, with the optical structure layer located on one of the surfaces of the imaging lens.

[0019] The imaging lens, located between the display screen and the reflective polarizer, is used for the transmission and refraction of light. Optical imaging systems can be configured with different lens types and numbers according to actual needs. By combining lenses, image quality can be improved to meet more imaging requirements; for example, increasing the number of imaging lenses can increase image sharpness. An optical structure layer is formed on one surface of the imaging lens, which facilitates the fabrication of the optical structure layer and reduces the size and weight of the optical imaging system.

[0020] Optionally, the imaging lens includes one or more of a Fresnel lens, a plano-convex lens, a biconvex lens, a meniscus positive lens, a plano-concave lens, a biconcave lens, or a meniscus negative lens.

[0021] Alternatively, the imaging lens can be an optical resin lens or a glass lens.

[0022] In one possible implementation, the first coupling structure is configured to correspond one-to-one with the pixels of the display screen. This configuration ensures that the display screen presents a uniform brightness and clear image.

[0023] In one possible implementation, the microcavity includes at least one of the following: microring (e.g., circular or elliptical ring), microsphere, microdisk, micropillar, microtube, microbubble, microcore ring, deformable cavity, Fabry-Perot cavity, or photonic crystal microcavity.

[0024] In one possible implementation, the optical imaging system further includes a first quarter-wave plate located between the optical structure layer and the reflective polarizer, wherein the first quarter-wave plate is used to convert the first circularly polarized light from the coupling structure into first polarized light, and to convert the second circularly polarized light from the coupling structure into second polarized light, and to convert the first polarized light from the reflective polarizer into the first circularly polarized light; the reflective polarizer is used to reflect the first polarized light from the first quarter-wave plate and to transmit the second polarized light from the first quarter-wave plate.

[0025] In one possible implementation, the first circularly polarized light is left-handed circularly polarized light, the second circularly polarized light is right-handed circularly polarized light, the first polarized light is S-light, and the second polarized light is P-light; or, the first circularly polarized light is right-handed circularly polarized light, the second circularly polarized light is left-handed circularly polarized light, the first polarized light is P-light, and the second polarized light is S-light.

[0026] In one possible implementation, the optical imaging system further includes a first polarizer and a second quarter-wave plate located between the display screen and the optical structure layer, wherein the first polarizer is used to transmit second polarized light; and the second quarter-wave plate is used to convert the second polarized light from the first polarizer into the first circularly polarized light and direct it toward the first coupling structure.

[0027] In a second aspect, an optical microstructure is provided, including a first coupling structure, a second coupling structure, a microcavity, and a coupling-out structure; the first coupling structure is used to couple first circularly polarized light from one side of a display screen into the microcavity, the microcavity is used to transmit the first circularly polarized light to the coupling-out structure, and the coupling-out structure is used to couple the first circularly polarized light out and direct it toward a reflective polarizer; the second coupling structure is used to couple the first circularly polarized light from one side of the reflective polarizer into the microcavity, the microcavity is also used to convert the first circularly polarized light from the second coupling structure into second circularly polarized light, and the coupling-out structure is also used to couple the second circularly polarized light out and direct it toward the reflective polarizer.

[0028] In one possible implementation, the first coupling structure includes a first coupling lens and a first coupling waveguide, the light-incident surface of the first coupling lens is directed toward the display screen, and the first coupling lens is connected to the microcavity via the first coupling waveguide.

[0029] In one possible implementation, the coupling structure includes a coupling lens and a coupling waveguide, the light-emitting surface of the coupling lens being oriented toward the reflective polarizer, and the coupling lens being connected to the microcavity via the coupling waveguide.

[0030] In one possible implementation, the second coupling structure includes a second coupling lens and a second coupling waveguide, the incident surface of the second coupling lens is directed toward the reflective polarizer, and the second coupling lens is connected to the microcavity via the second coupling waveguide.

[0031] In one possible implementation, the microcavity includes at least one of microrings, microspheres, microdisks, micropillars, microtubes, microbubbles, micro-core rings, deformable cavities, Fabry-Perot cavities, or photonic crystal microcavities.

[0032] In one possible implementation, the first circularly polarized light is left-handed circularly polarized light and the second circularly polarized light is right-handed circularly polarized light; or, the first circularly polarized light is right-handed circularly polarized light and the second circularly polarized light is left-handed circularly polarized light.

[0033] Thirdly, a head-mounted display device is provided, comprising an optical imaging system provided by any of the implementations of the first aspect or an optical microstructure provided by any of the implementations of the second aspect. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of an optical imaging system provided by related technology 1.

[0035] Figure 2 yes Figure 1 The diagram shows the imaging principle of the optical imaging system.

[0036] Figure 3 This is a schematic diagram of the optical imaging system provided by related technology 2.

[0037] Figure 4 yes Figure 3 The diagram shows the imaging principle of the optical imaging system.

[0038] Figure 5 This is a schematic diagram of wearing the head-mounted display device provided in the embodiments of this application.

[0039] Figure 6 This is a schematic diagram of a head-mounted display device applied in a certain game scenario.

[0040] Figure 7 yes Figure 6 The diagram shows the interaction between the game scene and the virtual world.

[0041] Figure 8 This is a schematic diagram of the modular structure of the main body.

[0042] Figure 9 This is a simplified diagram of the disassembled structure of a head-mounted display device.

[0043] Figure 10 This is a schematic diagram of the structure of the optical imaging system provided in the embodiments of this application.

[0044] Figure 11 This is a schematic diagram of the imaging principle of the optical imaging system provided in the embodiments of this application.

[0045] Figure 12 This is a top view of the optical structure layer provided in the embodiments of this application.

[0046] Figure 13 This is a schematic diagram of the optical microstructure provided in the embodiments of this application.

[0047] Figure 14 This is a schematic diagram of light propagation in an optical microstructure.

[0048] Figure 15 This is a schematic diagram of the optical path loss of the related technology and the solution of this application.

[0049] Figure label:

[0050] 100. Optical imaging system; 110. Display screen; 120. Reflective polarizer; 130. First quarter-wave plate; 140. First polarizer; 150. Second quarter-wave plate; 160. Third quarter-wave plate; 170. Second polarizer;

[0051] 200. Head-mounted display device; 210. Main body; 211. Housing; 212. Control device; 213. Eye-tracking system; 214. Wireless communication module; 220. Wearing part;

[0052] 300, Optical structural layer; 310, Optical microstructure; 311, Microcavity; 312, First coupling lens; 313, First coupling waveguide; 314, Coupling lens; 315, Coupling waveguide; 316, Second coupling lens; 317, Second coupling waveguide;

[0053] L1, first circularly polarized light; L2, second circularly polarized light. Detailed Implementation

[0054] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0055] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between the components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0056] In the description of this application, it should be understood that the terms "upper", "lower", "side", "front", "rear", etc., indicate the orientation or positional relationship based on the installation orientation or positional relationship, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0057] It should also be noted that in the embodiments of this application, the same reference numerals are used to represent the same component or part. For the same part in the embodiments of this application, the reference numerals may only be used to mark one part or component as an example. It should be understood that the reference numerals are also applicable to other identical parts or components.

[0058] Head-mounted devices (HMDs) can enhance or expand the real-world scene seen by users using additional information generated by computers, greatly changing the way humans interact with computers or the outside world. These devices integrate multiple technologies from different research fields and are rapidly being applied to entertainment, scientific research, simulation training, telemedicine, and other fields.

[0059] HMDs based on virtual reality (VR) technology can project digital content onto the viewer's eyes, making them feel as if they are in a virtual world, achieving an immersive virtual experience. The most crucial component in VR devices is the optical imaging system. Figure 1 This is a schematic diagram of the structure of an optical imaging system provided by related technology 1. For example... Figure 1 As shown, light emitted from the display screen is refracted by the imaging lens and enters the pupil of the human eye. The backward extensions of the light rays entering the pupil converge at a distance to form a virtual image, which is the image seen by the human eye. The virtual image is simply an enlarged image displayed on the display screen, and the angle at which this virtual image is open to the human eye is called the field of view (FoV).

[0060] Due to the realism requirements of VR devices, the image distance of any object needs to match the imaging angle of the entrance pupil to achieve a sufficiently realistic effect. Therefore, considering the main ray beam, the ray tracing from the entrance pupil in a VR device must be consistent with the actual object's image point in the real physical environment. Furthermore, due to the requirement of matching the angle with the physical depth of the actual object, the optical path in a VR device must be a very long physical path, much longer than the thickness of a comfortable-to-wear device. This is similar to... Figure 1 and Figure 2 The application of the pancake-folded optical path design shown is inevitable in VR devices.

[0061] Figure 2 yes Figure 1 The diagram shows the imaging principle of an optical imaging system. Figure 1 and Figure 2 As shown, the optical imaging system includes a display screen, a quarter wave plate (QWP) 1, a polarizer (POL) 1, a QWP 2, a 50 / 50 beam splitter (BS), a QWP 3, a reflective polarizer (RP), a POL 2, and an imaging lens.

[0062] The display screen is an image source used to display images. This display screen can be a microdisplay, such as a liquid crystal display (LCD), a liquid crystal on silicon (LCoS) display, an organic light-emitting diode (OLED) display, or a micro-light-emitting diode (Micro-LED) display, etc. The video light emitted by the display screen can be polarized or unpolarized light. For example, LCDs emit polarized light, while OLEDs emit unpolarized light.

[0063] A quarter-wave plate (QWP) can also be called a 45-degree phase retardation plate. A quarter-wave plate is made of a birefringent material. When the light vector of linearly polarized light forms a ±45° angle with the fast or slow axis of the waveplate, the light passing through the quarter-wave plate is circularly polarized; conversely, when circularly polarized light passes through the quarter-wave plate, it becomes linearly polarized.

[0064] A polarizer (POL) is an optical element that can convert natural light into polarized light. Polarizers can be divided into natural polarizers and artificial polarizers. Natural polarizers are made of crystal. Artificial polarizers can be composite materials laminated together from a polarizing film, an inner protective film, a pressure-sensitive adhesive layer, and an outer protective film. Based on the base color, polarizers can be divided into black-and-white polarizers and colored polarizers. Based on their application, polarizers can be classified into three types: transmission-type, transmission-reflection-type, and anti-transmission-type. For example, an absorptive polarizer has the function of both blocking and transmitting incident light. For instance, it can allow longitudinal light to pass through while blocking transverse light; or it can allow transverse light to pass through while blocking longitudinal light. In the embodiments of this application, the polarizer can be a linear polarizer. For example, it can be a metal wire grid type, a multilayer birefringent polymer film type, or a MacNeille type, etc. The polarized light transmitted by a linear polarizer is linearly polarized light, which can be P-light or S-light. It is understood that unpolarized light includes both P-light and S-light. P-rays are light rays whose polarization direction is parallel to a certain reference plane, which is related to the structure of the polarizer. S-rays are light rays whose polarization direction is perpendicular to the reference plane. Typically, linear polarizers (e.g., Figure 1 and Figure 2 POL1 and POL2 in the POL1 transmit P light and block S light.

[0065] A 50 / 50 beam splitter (BS) is used for transmission and reflection in folded optical paths. Each transmission and reflection indiscriminately results in a loss of half the light intensity, exhibiting characteristics of non-mutual benefit and indiscriminate reflection. A 50 / 50 beam splitter can be, for example, a semi-transparent, semi-reflective film, which allows incident light to partially pass through and partially reflect. For example, a film with both 50% transmittance and 50% reflectance. Transmission is the phenomenon of incident light exiting an object after refraction. The object through which light is transmitted is transparent or translucent, such as glass or a color filter. If the transparent object is colorless, most light passes through it, except for a small amount reflected. To represent the degree of light transmission, the ratio of the intensity of the transmitted light to the intensity of the incident light is typically used to characterize transmissivity. The ratio of the intensity of the reflected light to the intensity of the incident light is used to characterize reflectivity.

[0066] A reflective polarizer (RP) enables the polarizer to selectively reflect light. For example, a reflective polarizer can include a wire grid polarizer to transmit P-polarized light and reflect S-polarized light, i.e., transmit P-polarized light and reflect S-polarized light. Of course, in some cases, a reflective polarizer can also be configured to transmit S-polarized light and reflect P-polarized light.

[0067] An imaging lens is an optical element made of a transparent material. The material of an imaging lens can be glass or optical resin. Optical resin is an organic compound that is easy to injection mold or compression molded, not easily broken, has good light transmittance, and a density of less than 1.6 g / cm³. 3 Glass lenses can also be called phase-independent imaging lenses. Optical resin lenses can also be called phase-dependent imaging lenses. A phase-independent imaging lens means that when light passes through the device, light with different polarization directions does not introduce a phase difference, or it can be understood as the device not exhibiting birefringence. A phase-dependent imaging lens means that when light passes through the device, its polarization characteristics change, resulting in stray light or ghosting. The device exhibits birefringence, reducing image sharpness. For example, light that should transmit linearly polarized light (e.g., P-light or S-light) becomes elliptically polarized light, and light that should transmit circularly polarized light becomes elliptically polarized light. Typically, optical imaging systems use glass lenses for imaging. Furthermore, to further improve image sharpness, aberration compensation can be performed by increasing the number of imaging lenses in the optical imaging system to improve image sharpness.

[0068] The aforementioned quarter-wave plate (QWP), polarizer (POL), 50 / 50 beam splitter (BS), and reflective polarizer (RP) can be formed on the surface of the imaging lens as a coating layer or film. For example, Figure 1 and Figure 2The 50 / 50 beam splitter BS and QWP3 are formed on two opposing surfaces of one of the imaging lenses, while RP and POL2 are stacked on the surface of the other imaging lens facing the human eye.

[0069] like Figure 1 and Figure 2 As shown, the pancake-style folded optical path solution is currently the main solution in VR devices. The idea behind achieving the folded optical path is to use a reflective polarizer RP on one side to allow P-light to pass through and reflect S-light; while on the other side is a 50 / 50 beam splitter BS that does not distinguish polarization states, thus achieving the folding of the optical path. How the polarization state of the light changes between the two sides requires embedding quarter-wave plates QWP and polarizers POL, etc., and the specific implementation process will not be elaborated here.

[0070] It should be noted that because the input side uses a 50 / 50 beam splitter (BS), the VR device's optical path experiences one refraction and one reflection, resulting in a loss of 1 - 1 / 2 × 1 / 2 = 3 / 4 of the light intensity. Additionally, because the optical path needs to be polarized before the input side, half of the light intensity is lost at the outset. Therefore, theoretically, without considering the limited efficiency of the film for polarization state conversion in practice, the... Figure 1 and Figure 2 The optical imaging system shown will cause at least 1 - 1 / 2 × 1 / 2 × 1 / 2 = 7 / 8 of the actual entrance pupil light intensity loss.

[0071] To address the aforementioned issue of light intensity loss, several solutions based on the Faraday effect and special optical surfaces have been proposed, such as the magneto-optical materials (MOD) scheme in waveguides embedded in external fields. The aim of this scheme is to reduce the back-reflected light field during transmission, requiring a structure to break the symmetry of the physical field in both the forward and backward directions of light transmission. A common approach is to form a film using a magnetically responsive material. Under a certain magnetic field strength, this film breaks the time-reversal symmetry of the light field in both directions.

[0072] Figure 3 This is a schematic diagram of the optical imaging system provided by related technology 2. Figure 4 yes Figure 3 The diagram shows the imaging principle of the optical imaging system. Figure 3 and Figure 4In the optical imaging system shown, a magnetic response layer (MRL) can replace the 50 / 50 beam splitter in the previous embodiment. This MRL is made of a magnetically responsive material and, under the influence of a magnetic field (B-field), can achieve light transmission and reflection; that is, it can transmit forward light from front to back and reflect backward light from back to front, thereby breaking the time-reversal symmetry of visible light. Compared to the 50 / 50 beam splitter in the previous embodiment, the MRL does not cause additional light loss, thus reducing the overall light intensity loss of the optical imaging system.

[0073] However, Figure 3 and Figure 4 While the optical imaging system shown solves the light intensity loss problem of the pancake folding optical path scheme, it also introduces the following three significant problems:

[0074] (1) High cost. The magnetic material itself is a heavy metal hybrid, so the MRL film layer must be processed by complementary metal oxide semiconductor (CMOS) technology to form a structure with the best response to external field coupling, which is extremely costly.

[0075] (2) The application environment is very demanding. Generally, to break the time reversal symmetry in the visible light band, a magnetic field of about two Tesla (Tesla, T) is required. This field strength is beyond the normal range for humans and will react to local electromagnetic field perturbations.

[0076] (3) It is difficult to integrate into actual equipment. Because a strong electromagnetic field is required, other electronic components in HMD will inevitably have changes in electrical or optical properties under strong field or unisolated micro-perturbations. Therefore, it is very difficult to integrate magnetic films in practical applications.

[0077] In summary, the above analysis shows that using an MRL (Medium Linear Reflector) to transmit forward visible light from front to back and reflect backward visible light from back to front can reduce light intensity loss while achieving optical path folding. However, MRLs are expensive to produce, have stringent environmental requirements, and require a strong magnetic field, which may cause magnetic interference to other electronic components within the HMD (High-Density Mirroring Device). These factors significantly reduce the usability of MRL-based optical imaging systems and make implementation difficult. Therefore, providing a low-cost and easily implemented optical imaging system has become a pressing technical problem.

[0078] This application provides an optical imaging system that achieves light transmission and reflection by setting a microcavity-based optical structure layer. This optical structure layer is a purely passive hardware structure layer that does not require external field driving, giving the optical imaging system provided by this application advantages such as low cost and ease of implementation. This optical imaging system can be applied to head-mounted display devices. To facilitate understanding of the technical solution of this application, the head-mounted display device with this optical imaging system provided by this application embodiment will be introduced first, that is, the application background of this optical imaging system will be introduced first.

[0079] Please refer to this simultaneously. Figures 5 to 9 This application provides a head-mounted display device 200, which is a display device worn on the head to provide an immersive experience different from televisions, mobile phones, etc. The head-mounted display device 200 can be a VR device, an augmented reality (AR) display device, or a mixed reality (MR) display device, etc. The form of the head-mounted display device 200 can be, for example, glasses, a helmet, or a mask, but is not limited to these.

[0080] Figure 5 This is a schematic diagram illustrating the wearing of the head-mounted display device 200 provided in an embodiment of this application. Figure 5 As shown, when the head-mounted display device 200 is worn on a user's head, the user's eyes can see the image displayed on the screen of the head-mounted display device 200. When the screen is transparent, the user's eyes can also see physical objects in front of them through the screen. The application scenarios of the head-mounted display device 200 mainly involve various interactions with virtual scenes, such as an application that can recognize human gestures and facial expressions and perform high-bitrate interactions in real time using a certain communication protocol. The head-mounted display device 200 provided in this application embodiment will be described below with reference to a specific application scenario.

[0081] Figure 6 This is a schematic diagram of a head-mounted display device 200 applied in a certain game scenario. Figure 7 yes Figure 6 The diagram illustrates the interaction between the game scene and the virtual world. (See attached image.) Figure 6 and Figure 7 The game scenario shown can connect two people who are not in the same physical space. Their real-time body motion images, sounds and other information are respectively input into their respective head-mounted display devices 200, and they are fully immersed in a new reality that has been reconstructed based on the reality framework and has all the interacting parties present, with an extremely high sense of immersion.

[0082] Figure 6 and Figure 7 The illustration depicts a hypothetical game scenario where the physical environment and user of the head-mounted display device 200 on the left are mapped into the virtual reality perceived by the user on the right. Conversely, the actions and person of the user on the right head-mounted display device 200 are mapped into the real-world environment perceived by the user on the left, along with a virtual interactive tool (here, a "bow and arrow"). This game scenario allows two users, separated by physical space, to simultaneously experience an immersive and interactive virtual world.

[0083] like Figure 5 As shown, the head-mounted display device 200 provided in this embodiment includes a main body 210 and a wearing part 220. When a user wears the head-mounted display device 200, the main body 210 is located in front of the user's eyes to provide a display image for the user's eyes, while the wearing part 220 is used to fix it to the user's head or ears, thus achieving reliable wearing of the head-mounted display device 200. Figure 5 In the illustration, the wearing part 220 takes the form of a strap. In other embodiments, the wearing part 220 may also take the form of eyeglass temples or a helmet to hold the main body 210 on the user's head. When the wearing part 220 is in the form of a helmet, the wearing part 220 and the main body 210 may also be integrally formed.

[0084] Figure 8 This is a schematic diagram of the modular structure of the main body 210. (For example...) Figure 8 As shown, the main body 210 includes a housing 211, and various functional modules such as an optical imaging system 100, a control device 212, an eye-tracking system 213, and a wireless communication module 214. The housing 211 is used to install the aforementioned functional modules; for example, the functional modules can be installed inside the housing 211 or disposed on the housing 211.

[0085] Specifically, the housing 211 provides the external structure of the main body 210, and the remaining modules can be housed inside the housing 211 and protected by the housing 211.

[0086] Figure 9 This is a simplified schematic diagram of the disassembled structure of the head-mounted display device 200. (See diagram for example.) Figure 9 As shown, the optical imaging system 100 may include components such as a display screen and imaging lenses, used to provide a display image to the user, for example, to display a virtual image. There can be two optical imaging systems 100, corresponding to the user's left and right eyes respectively. The two optical imaging systems 100 can achieve stereoscopic imaging through interleaved display, image swapping, or parallax fusion.

[0087] like Figure 8 , Figure 9 As shown, the control device 212 is electrically connected to the optical imaging system 100 and is used to control the image displayed by the optical imaging system 100. The control device 212 may include functional devices such as a motherboard, a system-on-chip (SoC), and a graphics processing unit (GPU). For example, the motherboard and SoC can act as the control device 212 to output GPU-rendered images to the displays of the optical imaging system 100 for the left and right eyes. The displays corresponding to the left and right eyes will simulate the physical depth and light field angle of the actual object as completely as possible, and output images in conjunction with the SoC's inversion of image distortion caused by the optical system. The eye-tracking system 213 is also electrically connected to the control device 212 and is used to identify the user's gaze direction using eye-tracking technology. In some embodiments, the control device 212 may include a part electrically connected to the optical imaging system 100 and a part electrically connected to the eye-tracking system 213, with the two parts independently arranged inside the housing 211. In other embodiments, the control device 212 may also be a single unit; this application does not particularly limit the specific implementation of the control device 212.

[0088] The head-mounted display device 200 may also include a wireless communication module 214 disposed inside the housing 211 to enable wireless communication with other devices. This wireless communication module 214 may include, for example, a Wi-Fi module, a Bluetooth (BT) module, etc., but is not limited thereto. In addition, the head-mounted display device 200 may also include one or more functional modules such as a battery for powering the aforementioned modules, a camera module for capturing images or videos, a speaker for outputting audio, a microphone for acquiring user voice commands, and various sensors; this application does not limit the scope of these modules.

[0089] This application mainly relates to the structural improvement of the optical imaging system 100 in the head-mounted display device 200. As a core component in the head-mounted display device 200, the optical imaging system 100 provided in this application embodiment will be further described below with reference to the accompanying drawings.

[0090] Figure 10 This is a schematic diagram of the structure of the optical imaging system 100 provided in the embodiments of this application. Figure 11 This is a schematic diagram illustrating the imaging principle of the optical imaging system 100 provided in an embodiment of this application. For example... Figure 10 and Figure 11As shown, the optical imaging system 100 provided in this application embodiment includes a display screen 110 and a reflective polarizer 120, as well as an optical structure layer 300 disposed between the display screen 110 and the reflective polarizer 120. The display screen 110 and the reflective polarizer 120 can be referred to the aforementioned... Figures 1-4 The relevant content will be understood and will not be repeated here. The optical structure layer 300 is generally in the form of a film or sheet, and is disposed between the two, with one surface facing the display screen 110 and the other surface facing the reflective polarizer 120.

[0091] Figure 12 This is a top view of the optical structure layer 300 provided in an embodiment of this application. (See attached image.) Figure 12 As shown, the optical structure layer 300 includes a plurality of optical microstructures 310 arranged side by side on a surface parallel to the display screen 110, thereby forming the optical structure layer 300. Alternatively, the plurality of optical microstructures 310 are arranged side by side along the surface of the optical structure layer 300. The plurality of optical microstructures 310 are arranged in an array according to a certain pattern and spacing, and gaps can be formed between adjacent optical microstructures 310, with the gaps at any position being equal.

[0092] Figure 13 This is a schematic diagram of the optical microstructure 310 provided in the embodiments of this application. Figure 14 This is a schematic diagram of light propagation within the optical microstructure 310. (Example) Figures 12-14 As shown, the optical microstructure 310 includes a first coupling structure, a second coupling structure, a microcavity 311, and a coupling structure.

[0093] The first coupling structure is used to couple the first circularly polarized light L1 from one side of the display screen 110 into the microcavity 311. The microcavity 311 is used to transmit the first circularly polarized light L1 to the coupling structure. The coupling structure is used to couple the first circularly polarized light L1 out of the microcavity 311 and direct it toward the reflective polarizer 120. In other words, the optical microstructure 310 can transmit light from front to back (i.e., from the display screen 110 to the user's eyeball), and after the first circularly polarized light L1 enters the optical microstructure 310, it still exits as the first circularly polarized light L1, that is, the polarization state (phase) of the light does not change.

[0094] The second coupling structure is used to couple the first circularly polarized light L1 from one side of the reflective polarizer 120 into the microcavity 311. The microcavity 311 is also used to convert the first circularly polarized light L1 from the second coupling structure into a second circularly polarized light L2. The coupling structure is also used to couple the second circularly polarized light L2 out and direct it toward the reflective polarizer 120. In other words, the optical microstructure 310 can also reflect light from back to front (i.e., from the human eye to the display screen 110), and after the first circularly polarized light L1 enters the optical microstructure 310, the first circularly polarized light L1 is converted into the second circularly polarized light L2 and emitted as the second circularly polarized light L2, that is, the polarization state (phase) of the light changes.

[0095] For example, the first circularly polarized light L1 can be Figure 11 The left-handed (L) circularly polarized light in the middle, and the second circularly polarized light L2 are... Figure 11 The light in question is right-handed (R) circularly polarized light. Alternatively, the first circularly polarized light L1 can also be right-handed circularly polarized light, and the second circularly polarized light L2 can be left-handed circularly polarized light.

[0096] The optical imaging system 100 provided in this application includes a display screen 110, an optical structure layer 300, and a reflective polarizer 120 arranged sequentially. The optical structure layer 300 includes multiple optical microstructures 310 arranged in parallel. The optical microstructures 310 include structures such as microcavities 311, enabling the optical microstructures 310 to transmit first circularly polarized light L1 from one side of the display screen 110 and reflect first circularly polarized light L1 from one side of the reflective polarizer 120, converting it into second circularly polarized light L2. This allows the optical structure layer 300 to achieve light transmission and reflection, breaking the forward and reverse time reversal symmetry of the light field. Compared to the MRL scheme in related technology 2, the optical structure layer 300 in this application is a purely passive hardware structure layer that does not require external field driving. It has no special requirements for the materials used in its fabrication, is easy to manufacture, has a simple production process, and can reuse the optical path design of other existing parts. The system assembly steps are no different from those of a normal optical module. For these reasons, the optical imaging system 100 provided in this application has advantages such as low cost and ease of implementation, which is conducive to the large-scale promotion and application of the product.

[0097] Figure 15 This is a schematic diagram of the optical path loss of the related technology and the solution of this application. Figure 15 Part (a) in the diagram is a schematic diagram of the optical path loss of related technology one. Figure 15 Part (b) is a schematic diagram of the optical path loss of the scheme in this application, as shown below. Figure 15As shown, compared to the 50 / 50 beam splitter (semi-transparent and semi-reflective film) scheme in related technology one, the optical imaging system 100 provided in this application embodiment loses 50% of the light intensity in the initial polarization stage, and there is no further light intensity loss in the subsequent process. That is, the setting of the optical structure layer 300 will not cause additional light intensity loss. Compared with related technology one, the light intensity of the optical imaging system 100 provided in this application embodiment is nearly four times higher.

[0098] In this embodiment, the microcavity 311 is a key component of the optical structure layer 300 that enables light transmission and reflection. The microcavity 311 can convert the first circularly polarized light L1 from the side of the reflective polarizer 120 into the second circularly polarized light L2. The microcavity 311 in this embodiment will be further described below.

[0099] Microcavities, also known as optical microcavities, have attracted much attention and in-depth research due to their enormous application potential and scientific significance. Microcavities mainly include geometric shapes such as microspheres, micropillars, and microrings; they are shape-dependent optical resonators. Among these, the whispering gallery mode-based microcavity is the most representative. Light waves within a microcavity undergo total internal reflection at the microcavity interface, generating a resonant mode known as the whispering gallery mode (WGM), or echo-gallery mode. Compared to other optical resonators, microcavities possess a high Q value (greater than 10). 6 With its characteristics of low mode size, small size and easy integration, it has been applied to high-sensitivity biochemical sensing, ultra-low threshold lasers and nonlinear effects.

[0100] Optionally, the microcavity 311 in this embodiment can be a microcavity structure based on the whispering gallery mode, in which the first circularly polarized light L1 can be transmitted through total internal reflection within the microcavity 311.

[0101] Optionally, the microcavity 311 in the embodiments of this application includes a microring (such as...) Figures 12-14 As shown, for example, a ring or elliptical ring), microsphere, microdisk, micropillar, microtube, microbubble, microcore ring, deformable cavity, Fabry-Perot cavity or photonic crystal microcavity.

[0102] Optionally, the microcavity 311 in the embodiments of this application may include a single microcavity or may be formed by multiple microcavities occasionally interacting with each other.

[0103] In the design of the microcavity 311, considering that the human eye can only observe the visible light band, the first consideration is that the cavity width and thickness of the microcavity 311 must match the range of the visible light band. The relevant parameters are determined based on the n and k values ​​of the specific materials selected. Secondly, considering that visible light may propagate clockwise or counterclockwise within the microcavity 311, to ensure that the visible light can be successfully projected onto the reflective polarizer 120 instead of being reflected back to the display screen 110, the second step should consider coupling the counterclockwise propagation direction of the etched microcavity 311 to the visible light band. For example, this can be achieved by inputting a strong continuous wave (CW) laser beam to modulate the forward and reverse directions of the visible light band propagation, thus ensuring that the visible light propagates along... Figure 14 The light is transmitted counterclockwise, thus achieving complete transmission of the forward light field and complete reflection of the reverse light field. The specific reference formulas used to modulate the light field are shown in formulas (1) and (2) below:

[0104]

[0105]

[0106] Where I is the light intensity, Q is the quality factor of the microcavity 311, n and n' are the refractive indices of the linear and nonlinear microcavity 311, respectively, and V... mode Let η be the volume of the microcavity 311, η be the coupling coefficient of the microcavity 311, and the others be the center wavelength (λ0), the half-width at half maximum (WHM) of the offset wavelength (δλ), and the intensity of the modulation laser beam (P). in ).

[0107] like Figure 13 and Figure 14 As shown in part (a) of this application embodiment, the first coupling structure includes a first coupling lens 312 and a first coupling waveguide 313. The light incident surface of the first coupling lens 312 faces the display screen 110, and the first coupling lens 312 is connected to the microcavity 311 through the first coupling waveguide 313.

[0108] At this time, the first circularly polarized light L1 from the display screen 110 can enter the first coupling waveguide 313 through the light incident surface of the first coupling lens 312, and continue to be coupled into the microcavity 311 through the first coupling waveguide 313, where it will then undergo further coupling. Figure 14 The counterclockwise transmission shown in the diagram is followed by coupling out the first circularly polarized light L1 through the coupling structure and then exiting to the reflective polarizer 120.

[0109] The first coupling lens 312 can be set as large as possible to capture as much light as possible and ensure light transmission efficiency. The first coupling lens 312 can be in the shape of a bowl or a frustum. The larger side is the light-incident surface facing the display screen 110, while the smaller side opposite to the larger side can be connected to the first coupling waveguide 313. The first coupling waveguide 313 can be in the shape of a rod, for example, a straight rod. One end is connected to the first coupling lens 312, and the other end is connected to the microcavity 311 to ensure that light can form a path.

[0110] The above settings help simplify the structural design of the optical microstructure 310, reduce the processing difficulty, and facilitate the coupling of the first circularly polarized light L1 from one side of the display screen 110 into the optical microstructure 310.

[0111] like Figure 13 and Figure 14 As shown in part (b) of this application embodiment, the second coupling structure includes a second coupling lens 316 and a second coupling waveguide 317. The light incident surface of the second coupling lens 316 faces the reflective polarizer 120, and the second coupling lens 316 is connected to the microcavity 311 through the second coupling waveguide 317.

[0112] At this time, the first circularly polarized light L1 from the reflective polarizer 120 can enter the second coupling waveguide 317 through the incident surface of the second coupling lens 316, and continue to be transmitted and coupled into the microcavity 311 through the second coupling waveguide 317, where it is then subjected to... Figure 14 The counterclockwise transmission shown in the diagram involves the conversion of the first circularly polarized light L1 into the second circularly polarized light L2, which is then coupled out through a coupling structure and emitted to the reflective polarizer 120.

[0113] Similarly, the second coupling lens 316 can be made as large as possible to capture as much light as possible to ensure light transmission efficiency. The second coupling lens 316 can be in the shape of a bowl or a frustum, with the larger side serving as the light-incident surface facing the reflective polarizer 120, while the smaller side opposite to the larger side can be connected to the second coupling waveguide 317. The second coupling waveguide 317 can be in the shape of a rod, for example, a straight rod, with one end connected to the second coupling lens 316 and the other end connected to the microcavity 311 to ensure that light can form a path.

[0114] The above settings help simplify the structural design of the optical microstructure 310, reduce the processing difficulty, and facilitate the coupling of the first circularly polarized light L1 from the side of the reflective polarizer 120 into the optical microstructure 310.

[0115] Optionally, the first coupling waveguide 313 and the second coupling waveguide 317 can be integrally formed into a straight rod-shaped structure, that is, a part of the straight rod-shaped structure serves as the first coupling waveguide 313 and the other part serves as the second coupling waveguide 317, thereby simplifying the manufacturing process. Alternatively, the first coupling waveguide 313 and the second coupling waveguide 317 can also be connected to the microcavity 311 as two independent rod-shaped structures, which is not limited in this application.

[0116] like Figure 13 and Figure 14 As shown in the embodiment of this application, the coupling structure includes a coupling lens 314 and a coupling waveguide 315. The light-emitting surface of the coupling lens 314 faces the reflective polarizer 120, and the coupling lens 314 is connected to the microcavity 311 through the coupling waveguide 315.

[0117] At this time, the first circularly polarized light L1 in the microcavity 311 can be coupled out through the coupling waveguide 315 and transmitted to the coupling lens 314. Then, the first circularly polarized light L1 is emitted to the reflective polarizer 120 through the coupling lens 314. The second circularly polarized light L2 in the microcavity 311 can also be coupled out through the coupling waveguide 315 and transmitted to the coupling lens 314. Then, the second circularly polarized light L2 is emitted to the reflective polarizer 120 through the coupling lens 314.

[0118] Similarly, the coupling lens 314 can also be in the form of a bowl-shaped structure or a frustum-shaped structure, with the larger side serving as the light-emitting surface facing the reflective polarizer 120, while the smaller side opposite to the larger side can be connected to the coupling waveguide 315. The coupling waveguide 315 can be in the form of a rod, for example, a straight rod structure, with one end connected to the coupling lens 314 and the other end connected to the microcavity 311 to ensure that light can form a path.

[0119] The above settings help simplify the structural design of the optical microstructure 310, reduce the processing difficulty, and allow the transmitted and reflected light to share the same coupling structure, making it convenient for the transmitted and reflected light to be directed toward the reflective polarizer 120.

[0120] Optionally, the first coupling structure can be formed in Figure 13 or Figure 14 The second coupling structure can be formed at the upper left corner of the microcavity 311, while the coupling structure can be formed at the lower right corner. The three lenses—the first coupling lens 312, the second coupling lens 316, and the coupling lens 314—can have the same shape and size. The light-incident surface of the second coupling lens 316 and the light-exit surface of the coupling lens 314 can be located on the same plane. The coupling waveguide 315 can be arranged parallel or approximately parallel to the first coupling waveguide 313 and / or the second coupling waveguide 317.

[0121] Optionally, the optical microstructure 310 can be made into an integral structure from one or more materials through processes such as integral molding. For example, the constituent materials of the optical microstructure 310 include polymers (such as long-chain molecules like polyesteramide), silicon dioxide, silicon nitride, lithium niobate, calcium fluoride, barium fluoride, magnesium fluoride, diamond, glass, or silicon-based materials.

[0122] like Figure 9 and Figure 10 As shown, the optical imaging system 100 provided in this application embodiment also includes an imaging lens, and the optical structure layer 300 is located on one of the surfaces of the imaging lens.

[0123] An imaging lens is located between the display screen 110 and the reflective polarizer 120, used for transmitting and refracting light. The optical imaging system 100 can be configured with different lens types and numbers according to actual needs. By combining lenses, the image quality can be improved to meet more imaging requirements. For example, the image sharpness can be improved by increasing the number of imaging lenses. An optical structure layer 300 is formed on one surface of the imaging lens, which facilitates the fabrication of the optical structure layer 300 and reduces the size and weight of the optical imaging system 100.

[0124] Optionally, the imaging lens includes one or more of a Fresnel lens, a plano-convex lens, a biconvex lens, a meniscus positive lens, a plano-concave lens, a biconcave lens, or a meniscus negative lens.

[0125] Alternatively, the imaging lens can be an optical resin lens or a glass lens.

[0126] As one possible implementation, the imaging lens can be a glass lens, and the optical structure layer 300 can be made of materials such as polyesteramide long-chain molecules and silicon dioxide. The optical structure layer 300 is formed on the surface of the glass lens facing the display screen 110, and the glass lens constitutes the substrate of the optical structure layer 300. In this case, three lenses can be made using polyesteramide long-chain molecules, and silicon dioxide can be used to make the waveguides (i.e., the first coupling waveguide 313, the second coupling waveguide 317, and the coupling waveguide 315) and the microcavity 311 structure of the intermediate layer. The optical structure layer 300 can be formed by processing according to the following steps:

[0127] (1) A lens array consisting of a second coupling lens 316 and a coupling lens 314 is obtained by performing spin coating, exposure and etching processes on the surface of the glass lens facing the display screen 110.

[0128] (2) Continue chemical vapor deposition (CVD) growth, exposure, etching and other processes to obtain the intermediate layer waveguide (i.e., the first coupled waveguide 313, the second coupled waveguide 317 and the coupled waveguide 315) and microcavity 311.

[0129] (3) Repeat the spin coating, exposure and etching processes in step (1) to obtain an array of another lens (i.e., the first coupling lens 312).

[0130] Furthermore, in this embodiment, the first coupling structure is configured in a one-to-one correspondence with the pixels of the display screen 110. That is, the first coupling lens 312 is configured in a one-to-one correspondence with the pixels (main ray) of the display screen 110, and the first coupling lens 312 is matched one-to-one with the display units of the display screen 110. For example, their sizes are basically the same, and the minimal divergence angle and divergence distance of the main ray in the actual device need to be considered. Through the above configuration, it can be ensured that the display screen 110 presents a uniform brightness and clear image.

[0131] Furthermore, such as Figure 10 and Figure 11 As shown in this embodiment, the optical imaging system 100 further includes a first quarter-wave plate 130 located between the optical structure layer 300 and the reflective polarizer 120. The first quarter-wave plate 130 is used to convert first circularly polarized light L1 from the coupling structure into first polarized light, and to convert second circularly polarized light L2 from the coupling structure into second polarized light, and to convert first polarized light from the reflective polarizer 120 into first circularly polarized light L1. The reflective polarizer 120 is used to reflect the first polarized light from the first quarter-wave plate 130 and to transmit the second polarized light from the first quarter-wave plate 130.

[0132] Specifically, after the first circularly polarized light L1 from one side of the display screen 110 enters the optical microstructure 310, it is transmitted through the coupling lens 314. The first quarter-wave plate 130 receives the first circularly polarized light L1 from the coupling lens 314, converts it into first polarized light, and directs it towards the reflecting polarizer 120. The reflecting polarizer 120 then reflects the first polarized light back to the first quarter-wave plate 130, which converts it back into the first circularly polarized light L1 and directs it into the optical microstructure 310 through the second coupling lens 316. The optical microstructure 310 converts the first circularly polarized light L1 into second circularly polarized light L2, which is transmitted through the coupling lens 314. The first quarter-wave plate 130 receives the second circularly polarized light L2 from the coupling lens 314, converts it into second polarized light, directs it towards the reflecting polarizer 120, and then transmits it to the human eye.

[0133] Optionally, such as Figure 11 As shown in the embodiment of this application, the first circularly polarized light L1 is left-handed (L) circularly polarized light, the second circularly polarized light L2 is right-handed (R) circularly polarized light, the first polarized light is S light, and the second polarized light is P light.

[0134] At this point, after the left-hand circularly polarized light enters the optical microstructure 310, it is transmitted through the coupling lens 314 to the first quarter-wave plate 130. The first quarter-wave plate 130 converts the left-hand circularly polarized light into S-light and directs it towards the reflecting polarizer 120. The reflecting polarizer 120 reflects the S-light back to the first quarter-wave plate 130, which then converts the S-light back into left-hand circularly polarized light and sends it into the optical microstructure 310. The optical microstructure 310 converts the left-hand circularly polarized light into right-hand circularly polarized light and directs it towards the first quarter-wave plate 130. The first quarter-wave plate 130 converts the right-hand circularly polarized light into P-light and directs it towards the reflecting polarizer 120. The P-light is then transmitted through the reflecting polarizer 120 to the human eye.

[0135] Optionally, in the embodiments of this application, the first circularly polarized light L1 can also be right-handed circularly polarized light, in which case the second circularly polarized light L2 is left-handed circularly polarized light, the first polarized light is P light, and the second polarized light is S light.

[0136] Furthermore, such as Figure 10 and Figure 11As shown in the embodiment of this application, the optical imaging system 100 further includes a first polarizer 140 and a second quarter-wave plate 150 located between the display screen 110 and the optical structure layer 300. The first polarizer 140 is used to transmit second polarized light (e.g., P-light) and block first polarized light (e.g., S-light). The second quarter-wave plate 150 is used to convert the second polarized light from the first polarizer 140 into first circularly polarized light L1 (e.g., left-handed circularly polarized light) and direct it toward the first coupling structure of the optical microstructure 310.

[0137] Furthermore, such as Figure 10 and Figure 11 As shown in this embodiment, the optical imaging system 100 further includes a third quarter-wave plate 160 located between the display screen 110 and the first polarizer 140, and a second polarizer 170 located on the eye-facing side of the reflective polarizer 120. The third quarter-wave plate 160, the first polarizer 140, and the second quarter-wave plate 150 can be sequentially stacked on the surface of the display screen 110 facing the eye. The optical structure layer 300 is disposed on the surface of one of the lenses facing the display screen 110, and the first quarter-wave plate 130 is disposed on the eye-facing surface of that lens. The reflective polarizer 120 and the second polarizer 170 are stacked on the surface of the other lens facing the eye.

[0138] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An optical imaging system, characterized in that, Including a display screen (110) and a reflective polarizer (120), and also including: An optical structure layer (300) is located between the display screen (110) and the reflective polarizer (120). The optical structure layer (300) includes a plurality of optical microstructures (310) arranged in parallel. The optical microstructures (310) include a first coupling structure, a second coupling structure, a microcavity (311), and a coupling structure. The first coupling structure is used to couple the first circularly polarized light (L1) from one side of the display screen (110) into the microcavity (311), the microcavity (311) is used to transmit the first circularly polarized light (L1) to the coupling structure, and the coupling structure is used to couple the first circularly polarized light (L1) out and direct it toward the reflective polarizer (120). The second coupling structure is used to couple the first circularly polarized light (L1) from one side of the reflective polarizer (120) into the microcavity (311). The microcavity (311) is also used to convert the first circularly polarized light (L1) from the second coupling structure into second circularly polarized light (L2). The coupling structure is also used to couple the second circularly polarized light (L2) out and direct it toward the reflective polarizer (120).

2. The optical imaging system according to claim 1, characterized in that, The first coupling structure includes a first coupling lens (312) and a first coupling waveguide (313). The light-incident surface of the first coupling lens (312) faces the display screen (110), and the first coupling lens (312) is connected to the microcavity (311) through the first coupling waveguide (313).

3. The optical imaging system according to claim 1 or 2, characterized in that, The coupling structure includes a coupling lens (314) and a coupling waveguide (315). The light-emitting surface of the coupling lens (314) faces the reflective polarizer (120), and the coupling lens (314) is connected to the microcavity (311) through the coupling waveguide (315).

4. The optical imaging system according to any one of claims 1-3, characterized in that, The second coupling structure includes a second coupling lens (316) and a second coupling waveguide (317). The light incident surface of the second coupling lens (316) faces the reflective polarizer (120). The second coupling lens (316) is connected to the microcavity (311) through the second coupling waveguide (317).

5. The optical imaging system according to any one of claims 1-4, characterized in that, The optical imaging system also includes: An imaging lens, wherein the optical structure layer (300) is located on one of the surfaces of the imaging lens.

6. The optical imaging system according to any one of claims 1-5, characterized in that, The first coupling structure is configured to correspond one-to-one with the pixels of the display screen (110).

7. The optical imaging system according to any one of claims 1-6, characterized in that, The microcavity (311) includes at least one of the following: microring, microsphere, microdisk, microcolumn, microtube, microbubble, microcore ring, deformable cavity, Fabry-Perot cavity, or photonic crystal microcavity.

8. The optical imaging system according to any one of claims 1-7, characterized in that, The optical imaging system further includes a first quarter-wave plate (130) located between the optical structure layer (300) and the reflective polarizer (120), wherein, The first quarter-wave plate (130) is used to convert the first circularly polarized light (L1) from the coupling structure into first polarized light, and to convert the second circularly polarized light (L2) from the coupling structure into second polarized light, and to convert the first polarized light from the reflective polarizer (120) into the first circularly polarized light (L1). The reflective polarizer (120) is used to reflect the first polarized light from the first quarter-wave plate (130) and transmit the second polarized light from the first quarter-wave plate (130).

9. The optical imaging system according to claim 8, characterized in that, The first circularly polarized light (L1) is left-handed circularly polarized light, and the second circularly polarized light (L2) is right-handed circularly polarized light; the first polarized light is S-light, and the second polarized light is P-light; or... The first circularly polarized light (L1) is right-handed circularly polarized light, the second circularly polarized light (L2) is left-handed circularly polarized light, the first polarized light is P light, and the second polarized light is S light.

10. The optical imaging system according to any one of claims 1-9, characterized in that, The optical imaging system further includes a first polarizer (140) and a second quarter-wave plate (150) located between the display screen (110) and the optical structure layer (300), wherein, The first polarizer (140) is used to transmit second polarized light; The second quarter-wave plate (150) is used to convert the second polarized light from the first polarizer (140) into the first circularly polarized light (L1) and direct it toward the first coupling structure.

11. An optical microstructure, characterized in that, It includes a first coupling structure, a second coupling structure, a microcavity (311), and a coupling structure; The first coupling structure is used to couple the first circularly polarized light (L1) from the display screen (110) side into the microcavity (311), the microcavity (311) is used to transmit the first circularly polarized light (L1) to the coupling structure, and the coupling structure is used to couple the first circularly polarized light (L1) out and direct it toward the reflective polarizer (120). The second coupling structure is used to couple the first circularly polarized light (L1) from one side of the reflective polarizer (120) into the microcavity (311). The microcavity (311) is also used to convert the first circularly polarized light (L1) from the second coupling structure into second circularly polarized light (L2). The coupling structure is also used to couple the second circularly polarized light (L2) out and direct it toward the reflective polarizer (120).

12. The optical microstructure according to claim 11, characterized in that, The first coupling structure includes a first coupling lens (312) and a first coupling waveguide (313). The light-incident surface of the first coupling lens (312) is directed toward the display screen (110). The first coupling lens (312) is connected to the microcavity (311) through the first coupling waveguide (313).

13. The optical microstructure according to claim 11 or 12, characterized in that, The coupling structure includes a coupling lens (314) and a coupling waveguide (315). The light-emitting surface of the coupling lens (314) is directed toward the reflective polarizer (120). The coupling lens (314) is connected to the microcavity (311) through the coupling waveguide (315).

14. The optical microstructure according to any one of claims 11-13, characterized in that, The second coupling structure includes a second coupling lens (316) and a second coupling waveguide (317). The light-incident surface of the second coupling lens (316) is directed toward the reflective polarizer (120). The second coupling lens (316) is connected to the microcavity (311) through the second coupling waveguide (317).

15. The optical microstructure according to any one of claims 11-14, characterized in that, The microcavity (311) includes at least one of the following: microring, microsphere, microdisk, microcolumn, microtube, microbubble, microcore ring, deformable cavity, Fabry-Perot cavity, or photonic crystal microcavity.

16. The optical microstructure according to any one of claims 11-15, characterized in that, The first circularly polarized light (L1) is left-handed circularly polarized light, and the second circularly polarized light (L2) is right-handed circularly polarized light; or, The first circularly polarized light (L1) is right-handed circularly polarized light, and the second circularly polarized light (L2) is left-handed circularly polarized light.

17. A head-mounted display device, characterized in that, Includes the optical imaging system as described in any one of claims 1-10 or the optical microstructure as described in any one of claims 11-16.

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