Visual optical system

Abstract

This application discloses a visual optical system, which sequentially includes, from a first side to a second side, the following along the optical axis: a first lens with positive optical power, wherein the near-optical axis region of its first side is concave and the near-optical axis region of its second side is convex; a reflective polarizing element; a quarter-wave plate; a second lens with optical power, wherein its first side is planar; and a third lens with optical power. The visual optical system satisfies: 6.0 < f1 / R2 / (F2 / R4) < 9.2 and 13.4 < f2 / CT2 < 21.7, where f1 is the effective focal length of the first lens, R2 is the radius of curvature of the second side of the first lens, F2 is the combined focal length of the reflective polarizing element, the quarter-wave plate, and the second lens, R4 is the radius of curvature of the second side of the second lens, f2 is the effective focal length of the second lens, and CT2 is the center thickness of the second lens along the optical axis.

Description

Technical Field

[0001] This application relates to the field of optical components, and more specifically, to a visual optical system. Background Technology

[0002] Virtual Reality (VR) technology, based on computer science and interwoven with multiple disciplines such as graphics processing and optical display, is breaking through the limitations of traditional space. VR is a computer-generated, interactive, and immersive three-dimensional visual virtual environment that can integrate diverse information to create dynamic three-dimensional scenes. It can generate various virtual environments as needed and plays an important role in many fields such as entertainment, urban planning, driver training, and interior design.

[0003] Since the concept of the "metaverse" was proposed, VR has ushered in its second opportunity for development. Visual optical systems, as the entry point for human-computer interaction in VR devices, play a crucial role. At the same time, users are placing more stringent demands on the projection quality and user experience of visual optical systems.

[0004] Current visual optical systems generally suffer from drawbacks such as large size, heavy weight, and poor imaging and / or projection quality at the edges of the field of view. Therefore, miniaturization, weight reduction, and high imaging and / or projection quality have become the most important factors in improving the consumer experience. How to eliminate the shortcomings of current visual optical systems, improve their imaging and / or projection quality, and reduce their overall length has become one of the most pressing challenges for many visual optical system designers. Summary of the Invention

[0005] This application provides a visual optical system. The visual optical system comprises, sequentially from a first side to a second side along the optical axis: a first lens with positive optical power, wherein the near-optical axis region of its first side is concave and the near-optical axis region of its second side is convex; a reflective polarizing element; a quarter-wave plate; a second lens with optical power, wherein its first side is planar; and a third lens with optical power. The visual optical system satisfies: 6.0 < f1 / R2 / (F2 / R4) < 9.2 and 13.4 < f2 / CT2 < 21.7, where f1 is the effective focal length of the first lens, R2 is the radius of curvature of the second side of the first lens, F2 is the combined focal length of the reflective polarizing element, the quarter-wave plate, and the second lens, R4 is the radius of curvature of the second side of the second lens, f2 is the effective focal length of the second lens, and CT2 is the center thickness of the second lens along the optical axis.

[0006] In one embodiment, at least one of the mirror surfaces of the first side surface of the first lens to the second side surface of the third lens is an aspherical mirror surface.

[0007] In one embodiment, the visual optical system can satisfy: 1.7 < (R4 + R2) / (R4 - R2) < 7.5, where R2 is the radius of curvature of the second side surface of the first lens and R4 is the radius of curvature of the second side surface of the second lens.

[0008] In one embodiment, the third lens has positive optical power, and the radii of curvature of its first and second sides have the same positive and negative properties.

[0009] In one embodiment, the visual optical system can satisfy: -0.6 < (SAG31 + SAG32) / f3 < 2.0, where SAG31 is the distance on the optical axis from the intersection of the first side surface of the third lens with the optical axis to the effective radial vertex of the first side surface of the third lens, SAG32 is the distance on the optical axis from the intersection of the second side surface of the third lens with the optical axis to the effective radial vertex of the second side surface of the third lens, and f3 is the effective focal length of the third lens.

[0010] In one embodiment, the visual optical system can satisfy: -6.5 < R4 / (CT2+ET2) < -3.5, where R4 is the radius of curvature of the second side surface of the second lens, CT2 is the center thickness of the second lens on the optical axis, and ET2 is the edge thickness at the maximum effective radius of the second lens.

[0011] In one embodiment, the visual optical system may satisfy: 1.0 < (DT21 + DT22) / (DT11 + DT12) < 1.5, where DT11 is the effective half-aperture of the first side of the first lens, DT12 is the effective half-aperture of the second side of the first lens, DT21 is the effective half-aperture of the first side of the second lens, and DT22 is the effective half-aperture of the second side of the second lens.

[0012] In one embodiment, the visual optical system may satisfy: 0.8 < (SAG11 + SAG12) / SAG22 < 3.0, where SAG11 is the distance on the optical axis from the intersection of the first side surface of the first lens with the effective radial vertex of the first side surface of the first lens, SAG12 is the distance on the optical axis from the intersection of the second side surface of the first lens with the effective radial vertex of the second side surface of the first lens, and SAG22 is the distance on the optical axis from the intersection of the second side surface of the second lens with the effective radial vertex of the second side surface of the second lens.

[0013] In one embodiment, the visual optical system may satisfy: 10.5 < ET2 / ET1 < 21.2, where ET2 is the edge thickness at the maximum effective radius of the second lens, and ET1 is the edge thickness at the maximum effective radius of the first lens.

[0014] In one embodiment, the visual optical system can satisfy: 0 < BFL / (CT1+CT3) < 1.7, where BFL is the distance on the optical axis from the second side of the third lens to the display screen of the visual optical system, CT1 is the center thickness of the first lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

[0015] In one embodiment, the visual optical system may satisfy: SAG22 / SAG12 < 1.3, where SAG12 is the distance on the optical axis from the intersection of the second side surface of the first lens with the optical axis to the effective radial vertex of the second side surface of the first lens with the optical axis, and SAG22 is the distance on the optical axis from the intersection of the second side surface of the second lens with the optical axis to the effective radial vertex of the second side surface of the second lens with the optical axis.

[0016] In one embodiment, the visual optical system may satisfy: 0.7 < V2 / V3 < 2.7, where V2 is the Abbe number of the second lens and V3 is the Abbe number of the third lens.

[0017] In one embodiment, the visual optical system may satisfy: 0.5 < V1 / V3 < 2.7, where V1 is the Abbe number of the first lens and V3 is the Abbe number of the third lens.

[0018] In one embodiment, the visual optical system further includes a partial reflective element disposed on a second side of the second lens.

[0019] In one embodiment, the visual optical system may satisfy: 1.0 < F2 / f < 1.5, where F2 is the combined focal length of the reflective polarizing element, the quarter-wave plate, and the second lens, and f is the total effective focal length of the visual optical system.

[0020] In one embodiment, the visual optical system can satisfy: 4.0 < (f1 + F2) / f < 7.5, where f1 is the effective focal length of the first lens, F2 is the combined focal length of the reflective polarizing element, the quarter-wave plate, and the second lens, and f is the total effective focal length of the visual optical system.

[0021] In one embodiment, the visual optical system may satisfy: 1.2 < TTL / CT2 < 3.0, where TTL is the distance on the optical axis from the first side of the first lens to the display screen of the visual optical system, and CT2 is the center thickness of the second lens on the optical axis.

[0022] In one implementation, the visual optical system may satisfy: 7.2 < FNO × TAN (Semi-FOV) < 8.0, where FNO is the aperture number of the visual optical system and Semi-FOV is half of the maximum field of view of the visual optical system.

[0023] In an exemplary embodiment of this application, by reasonably setting the three lenses, the optical power and surface shape of some lenses, the reflective polarizing element, and the quarter-wave plate, and by combining 6.0 < f1 / R2 / (F2 / R4) < 9.2 and 13.4 < f2 / CT2 < 21.7, the visual optical system provided by this application can have characteristics such as small overall length, edge field of view imaging, strong manufacturability, and / or high projection quality. For example, by setting the reflective polarizing element, the quarter-wave plate, and the second lens, these three components can bear the main optical power of the system. At the same time, by controlling the ratio of the effective focal length to the radius of curvature of the first and second lenses, as well as the shape of the first and second lenses, the main optical power of the system can be allocated, effectively shortening the overall length of the system. Furthermore, by setting the near-optical axis region of the first lens to a meniscus shape, the spherical aberration of the system can be effectively reduced while controlling the field curvature of the system, thereby improving the imaging and / or projection quality of the edge field of view and enhancing the imaging and / or projection quality of the optical system in a large field of view. At the same time, by controlling the ratio of the effective focal length of the second lens to the center thickness of the second lens, the center thickness and radius of curvature of the second lens can be controlled to a certain extent, giving the second lens good manufacturability. Attached Figure Description

[0024] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0025] Figure 1 This is a schematic diagram of the visual optical system in Example 1;

[0026] Figures 2A to 2C The on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the visual optical system of Example 1 are shown respectively.

[0027] Figure 3 This is a schematic diagram of the visual optical system in Example 2;

[0028] Figures 4A to 4C The on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the visual optical system of Example 2 are shown respectively.

[0029] Figure 5 This is a schematic diagram of the visual optical system in Example 3;

[0030] Figures 6A to 6C The on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the visual optical system of Example 3 are shown respectively.

[0031] Figure 7 This is a schematic diagram of the visual optical system in Example 4;

[0032] Figures 8A to 8CThe on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the visual optical system of Example 4 are shown respectively.

[0033] Figure 9 This is a schematic diagram of the visual optical system in Example 5;

[0034] Figures 10A to 10C The on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the visual optical system of Example 5 are shown respectively.

[0035] Figure 11 This is a schematic diagram of the visual optical system in Example 6;

[0036] Figures 12A to 12C The on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the visual optical system of Example 6 are shown respectively; and

[0037] Figure 13 This is a partially enlarged schematic diagram of a visual optical system according to an embodiment of this application. Detailed Implementation

[0038] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0039] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of this application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0040] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0041] In this document, the optical axis region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the optical axis region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the optical axis region. The first side refers to, for example, the side closer to the user's eye, and the second side refers to, for example, the side closer to the display screen, where the display screen may have an image source surface. The surface of each lens closest to the first side is called the first side surface of the lens, and the surface of each lens closest to the second side is called the second side surface of the lens.

[0042] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0043] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formalized sense, unless expressly so specified herein.

[0044] It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other. The following embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application.

[0045] The features, principles and other aspects of this application are described in detail below.

[0046] A visual optical system according to an exemplary embodiment of this application may include three lenses with optical power, namely a first lens, a second lens, and a third lens. These three lenses are arranged sequentially along the optical axis from the first side to the second side. Any two adjacent lenses among the first to third lenses may have a gap distance between them.

[0047] In an exemplary implementation, such as Figure 1As shown, the visual optical system according to this application further includes a reflective polarizing element RP and a quarter-wave plate QWP located between the first lens E1 and the second lens E2. Exemplarily, as... Figure 13 As shown, the quarter-wave plate QWP can be attached to the first side of the second lens E2. The reflective polarizing element RP can be attached to the surface of the quarter-wave plate QWP. In other words, the second side of the quarter-wave plate QWP can be attached to the first side of the second lens E2. The second side of the reflective polarizing element RP can be attached to the first side of the quarter-wave plate QWP.

[0048] In an exemplary implementation, such as Figure 13 As shown, the visual optical system according to this application also includes a partially reflective element BS attached to the second side surface of the second lens E2. The partially reflective element BS can be a semi-reflective and semi-transparent film, that is, it can be configured to allow a portion of the light to pass through while the other portion of the light is reflected. The partially reflective element BS can serve as one of the key components for realizing the folded optical path in the visual optical system provided in this application. For example, the second side surface of the second lens has a large radius of curvature. Arranging the partially reflective element BS on the second side surface of the second lens can effectively reduce the attachment difficulty of the partially reflective element BS and ensure its manufacturability.

[0049] In an exemplary implementation, such as Figure 1 As shown, the visual optical system according to this application also includes an aperture STO disposed on the first side and a display screen S9 disposed on the second side. The user's eyes can view the image projected by the display screen S9 at the position of the aperture STO. That is, the image light on the display screen S9 is finally projected to the user's eyes after multiple refractions and reflections through the third lens E3, the partial reflective element BS, the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, and the first lens E1.

[0050] This application, by reasonably setting up a reflective polarizing element RP, a quarter-wave plate QWP, a partial reflective element BS, and multiple lenses such as the first lens E1, the second lens E2, and the third lens E3, can reduce the length of the lens group required for system projection without affecting the projection quality by utilizing light reflection and / or refraction.

[0051] According to exemplary embodiments of this application, such as Figure 1As shown, the image light emitted by the light source can be emitted from the display screen S9 on the second side, and passes sequentially through the third lens E3 and the second lens E2 to the first side of the quarter-wave plate QWP, where it is reflected to form the first reflected image light. The first reflected image light passes through the quarter-wave plate QWP to the partial reflective element BS of the second lens E2, where it is reflected to form the second reflected image light. The second reflected image light passes sequentially through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, and the first lens E1 to the aperture stop STO (i.e., the position where the user's eye views the image). This application can fold the required optical path by combining light reflection and refraction, which can effectively shorten the length of the visual optical system.

[0052] In an exemplary embodiment, the first lens may have positive optical power, the near-optical axis region of its first side may be concave, and the near-optical axis region of its second side may be convex; the first side of the second lens may be planar.

[0053] In an exemplary embodiment, the visual optical system according to this application satisfies: 6.0 < f1 / R2 / (F2 / R4) < 9.2 and 13.4 < f2 / CT2 < 21.7, where f1 is the effective focal length of the first lens, R2 is the radius of curvature of the second side of the first lens, F2 is the combined focal length of the reflective polarizing element, the quarter-wave plate, and the second lens, R4 is the radius of curvature of the second side of the second lens, f2 is the effective focal length of the second lens, and CT2 is the center thickness of the second lens on the optical axis.

[0054] In this application, by rationally setting three lenses, the optical power and surface shape of some lenses, a reflective polarizing element, and a quarter-wave plate, and by combining 6.0 < f1 / R2 / (F2 / R4) < 9.2 and 13.4 < f2 / CT2 < 21.7, the visual optical system provided by this application can have characteristics such as small overall length, edge field of view imaging, strong manufacturability, and / or high projection quality. For example, by setting a reflective polarizing element, a quarter-wave plate, and a second lens, these three components can bear the main optical power of the system. At the same time, by controlling the ratio of the effective focal length to the radius of curvature of the first and second lenses, as well as the shape of the first and second lenses, the main optical power of the system can be distributed, effectively shortening the overall length of the system. Furthermore, by setting the near-optical axis region of the first lens to a meniscus shape, the spherical aberration of the system can be effectively reduced while controlling the field curvature of the system, thereby improving the imaging and / or projection quality of the edge field of view and enhancing the imaging and / or projection quality of the optical system in a large field of view. At the same time, by controlling the ratio of the effective focal length of the second lens to the center thickness of the second lens, the center thickness and radius of curvature of the second lens can be controlled to a certain extent, giving the second lens good manufacturability.

[0055] In an exemplary embodiment, the visual optical system according to this application satisfies: 1.7 < (R4 + R2) / (R4 - R2) < 7.5, where R2 is the radius of curvature of the second side surface of the first lens, and R4 is the radius of curvature of the second side surface of the second lens. By satisfying 1.7 < (R4 + R2) / (R4 - R2) < 7.5, the ratio of the radii of curvature of the second side surface of the first lens to the second side surface of the second lens can be controlled to effectively control the light path of the system light rays through the first and second lenses, thereby facilitating CRA matching with the system.

[0056] In an exemplary embodiment, the third lens has positive optical power, and the radii of curvature of its first and second side surfaces have the same positive and negative properties. This configuration of optical power and surface shape of the third lens facilitates a meniscus structure, which can reduce the introduction of spherical aberration and help reduce system field curvature.

[0057] In an exemplary embodiment, the visual optical system according to this application satisfies: -0.6 < (SAG31 + SAG32) / f3 < 2.0, where SAG31 is the distance on the optical axis from the intersection of the first side surface of the third lens with the effective radial vertex of the first side surface of the third lens, SAG32 is the distance on the optical axis from the intersection of the second side surface of the third lens with the effective radial vertex of the second side surface of the third lens, and f3 is the effective focal length of the third lens. By satisfying -0.6 < (SAG31 + SAG32) / f3 < 2.0, the shape of the third lens can be controlled by adjusting the ratio of the sagittal height of the first and second side surfaces of the third lens to the effective focal length of the third lens. This improves the manufacturability of the third lens while ensuring a reasonable allocation of the optical power of each component.

[0058] In an exemplary embodiment, the visual optical system according to this application satisfies: -6.5 < R4 / (CT2+ET2) < -3.5, where R4 is the radius of curvature of the second side surface of the second lens, CT2 is the center thickness of the second lens on the optical axis, and ET2 is the edge thickness at the maximum effective radius of the second lens. By satisfying -6.5 < R4 / (CT2+ET2) < -3.5, the surface shape of the second side surface of the second lens can be controlled by adjusting the numerical relationship between the radius of curvature of the second side surface and the center and edge thicknesses of the second lens, ensuring that the second lens has a reasonable thickness ratio.

[0059] In an exemplary embodiment, the optical system according to this application satisfies: 1.0 < (DT21 + DT22) / (DT11 + DT12) < 1.5, where DT11 is the effective half-aperture of the first side of the first lens, DT12 is the effective half-aperture of the second side of the first lens, DT21 is the effective half-aperture of the first side of the second lens, and DT22 is the effective half-aperture of the second side of the second lens. Satisfying 1.0 < (DT21 + DT22) / (DT11 + DT12) < 1.5 allows for the reasonable setting of the effective apertures of the two lenses by controlling the ratio of their effective apertures. This is beneficial for constraining the light path of the system and for avoiding large step differences, thus improving the stability of the system assembly.

[0060] In an exemplary embodiment, the visual optical system according to this application satisfies: 0.8 < (SAG11 + SAG12) / SAG22 < 3.0, where SAG11 is the distance on the optical axis from the intersection of the first side surface of the first lens with the effective radial vertex of the first side surface of the first lens, SAG12 is the distance on the optical axis from the intersection of the second side surface of the first lens with the effective radial vertex of the second side surface of the first lens, and SAG22 is the distance on the optical axis from the intersection of the second side surface of the second lens with the effective radial vertex of the second side surface of the second lens. Satisfying 0.8 < (SAG11 + SAG12) / SAG22 < 3.0 allows for effective constraint of the surface profile of the first lens and improves its manufacturability by controlling the relationship between the sagitta of the first and second side surfaces of the first lens and the sagitta of the second side surface of the second lens.

[0061] In an exemplary embodiment, the visual optical system according to this application satisfies: 10.5 < ET2 / ET1 < 21.2, where ET2 is the edge thickness at the maximum effective radius of the second lens, and ET1 is the edge thickness at the maximum effective radius of the first lens. Satisfying 10.5 < ET2 / ET1 < 21.2 allows for the control of the edge thickness ratio at the effective radii of the first and second lenses, simultaneously constraining the edge thicknesses of both lenses. This not only facilitates the subsequent installation of support components at the edges of the two lenses but also improves the manufacturability of the two lenses.

[0062] In an exemplary embodiment, the visual optical system according to this application satisfies: 0 < BFL / (CT1+CT3) < 1.7, where BFL is the distance on the optical axis from the second side of the third lens to the display screen of the visual optical system, CT1 is the center thickness of the first lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis. By satisfying 0 < BFL / (CT1+CT3) < 1.7, the ratio of the system's back focal length BFL to the center thicknesses of the first and third lenses can be controlled within a reasonable range while meeting the system's optical power requirements.

[0063] In an exemplary embodiment, the visual optical system according to this application satisfies: SAG22 / SAG12 < 1.3, where SAG12 is the distance on the optical axis from the intersection of the second side surface of the first lens with the optical axis to the effective radial vertex of the second side surface of the first lens, and SAG22 is the distance on the optical axis from the intersection of the second side surface of the second lens with the optical axis to the effective radial vertex of the second side surface of the second lens. Satisfying SAG22 / SAG12 < 1.3 allows for the reasonable allocation of the system's optical power by controlling the ratio of the sagittal heights of the second side surface of the first and second lenses, and also constrains the shapes of the second side surfaces of the first and second lenses, improving the manufacturability of these two lenses.

[0064] In an exemplary embodiment, the visual optical system according to this application satisfies: 0.7 < V2 / V3 < 2.7, where V2 is the Abbe number of the second lens and V3 is the Abbe number of the third lens. Satisfying 0.7 < V2 / V3 < 2.7 allows for the reasonable allocation of the dispersion of the second and third lenses by controlling the relationship between their Abbe numbers, and also facilitates the selection of more suitable lens materials.

[0065] In an exemplary embodiment, the visual optical system according to this application satisfies: 0.5 < V1 / V3 < 2.7, where V1 is the Abbe number of the first lens and V3 is the Abbe number of the third lens. Satisfying 0.5 < V1 / V3 < 2.7 allows for the reasonable allocation of dispersion between the first and third lenses by controlling the relationship between their Abbe numbers, and also facilitates the selection of more suitable lens materials.

[0066] In an exemplary embodiment, the visual optical system according to this application satisfies the following condition: 1.0 < F2 / f < 1.5, where F2 is the combined focal length of the reflective polarizing element, the quarter-wave plate, and the second lens, and f is the total effective focal length of the visual optical system. By satisfying 1.0 < F2 / f < 1.5, the optical power of the main lenses in the system can be reasonably allocated by controlling the ratio of the combined focal length of the reflective polarizing element, the quarter-wave plate, and the second lens to the total effective focal length of the visual optical system, thus ensuring the rationality of the system structure.

[0067] In an exemplary embodiment, the visual optical system according to this application satisfies: 4.0 < (f1 + F2) / f < 7.5, where f1 is the effective focal length of the first lens, F2 is the combined focal length of the reflective polarizing element, the quarter-wave plate, and the second lens, and f is the total effective focal length of the visual optical system. In this application, the first lens, the reflective polarizing element, the quarter-wave plate, and the second lens constitute the main reflective optical path of the system and bear the main optical power of the system. By controlling the focal length of these lenses, a reasonable distribution of the system's optical power can be ensured, and it is beneficial for the miniaturization design of the system.

[0068] In an exemplary embodiment, the visual optical system according to this application satisfies: 1.2 < TTL / CT2 < 3.0, where TTL is the distance on the optical axis from the first side of the first lens to the display screen of the visual optical system, and CT2 is the center thickness of the second lens on the optical axis. Satisfying 1.2 < TTL / CT2 < 3.0 allows for pre-allocation of the system's optical power by controlling the relationship between the center thickness of the second lens and the total length of the system, ensuring the optical power contribution of the second lens and facilitating the control of the second lens's thickness within a reasonable range.

[0069] In an exemplary embodiment, the visual optical system according to this application satisfies: 7.2 < FNO × TAN (Semi-FOV) < 8.0, where FNO is the aperture number of the visual optical system, and Semi-FOV is half of the maximum field of view of the visual optical system. In this application, by reasonably setting three lenses, the optical power and surface shape of some lenses, reflective polarizing elements, and a quarter-wave plate, and in conjunction with 7.2 < FNO × TAN (Semi-FOV) < 8.0, the numerical relationship between the aperture number and the field of view of the visual optical system can be controlled to achieve the selection of a reasonable aperture number while meeting the field of view design requirements. This is beneficial for improving the edge image quality of the system and for realizing the miniaturization design of the optical system.

[0070] In an exemplary embodiment, the visual optical system according to this application may further include a filter for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the second side.

[0071] The visual optical system according to the above embodiments of this application can employ multiple lenses, such as the three lenses described above. By rationally allocating the structure of each lens and the on-axis spacing between them, the size of the visual optical system can be effectively reduced and its manufacturability improved, making it more suitable for manufacturing and production and applicable to portable electronic products. The visual optical system configured as described above features small size, light weight, good assembly stability, good edge field of view imaging and / or projection quality, large field of view, high manufacturability, compact structure, and good projection quality, which can well meet the usage needs of various portable electronic products in projection scenarios.

[0072] In embodiments of this application, at least one of the mirror surfaces of each lens is an aspherical mirror surface; that is, at least one mirror surface from the first side surface of the first lens to the second side surface of the third lens is an aspherical mirror surface. An aspherical lens is characterized by a continuously changing curvature from the lens center to the lens periphery. Unlike a spherical lens, which has a constant curvature from the lens center to the lens periphery, an aspherical lens has better curvature radius characteristics, offering advantages in improving distortion aberrations and astigmatism. By using an aspherical lens, aberrations occurring during projection can be eliminated as much as possible, thereby improving projection quality. Optionally, at least one of the first and second side surfaces of each of the first, second, and third lenses is an aspherical mirror surface. Optionally, the second side surface of the second lens, and the first and second side surfaces of the first and third lenses are all aspherical mirror surfaces.

[0073] However, those skilled in the art will understand that the number of lenses constituting the visual optical system can be varied to obtain the various results and advantages described herein without departing from the technical solutions claimed in this application. For example, although three lenses are described as an example in the embodiments, the visual optical system is not limited to including three lenses. If desired, the visual optical system may also include other numbers of lenses.

[0074] Specific embodiments of the visual optical system applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

[0075] Example 1

[0076] The following is for reference Figures 1 to 2C A visual optical system according to Embodiment 1 of this application is described. Figure 1 It is the visual optical system in Example 1.

[0077] like Figure 1As shown, the visual optical system includes, from the first side to the second side, the following components in sequence: aperture STO, first lens E1, reflective polarizing element RP, quarter-wave plate QWP, second lens E2, partial reflective element BS (not shown), third lens E3, and display screen S9.

[0078] The first lens E1 has positive optical power, with its first side surface S1 being concave and its second side surface S2 being convex. The second lens E2 has positive optical power, with its first side surface S5 being planar and its second side surface S6 being convex. The third lens E3 has positive optical power, with its first side surface S7 being convex and its second side surface S8 being concave. A quarter-wave plate QWP is attached to the first side surface S5 of the second lens E2. A reflective polarizing element RP is attached to the first side surface of the quarter-wave plate QWP. A partial reflective element BS is attached to the second side surface S6 of the second lens E2.

[0079] In this example, a light source may be provided on the display screen S9. Image light from the display screen S9 sequentially passes through the third lens E3, the second lens E2, and reaches the first side of the quarter-wave plate QWP, where it undergoes a first reflection. The light after the first reflection passes through the quarter-wave plate QWP and reaches the partial reflective element BS on the second side of the second lens E2, where it undergoes a second reflection. The light after the second reflection sequentially passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, and the first lens E1, and is finally projected onto a target object (not shown) in space. For example, when this visual optical system is mounted on an electronic device such as VR, the light after the two reflections is finally projected into the eyes of the user.

[0080] Table 1 shows the basic parameters of the visual optical system of Example 1, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0081]

[0082]

[0083] Table 1

[0084] In this example, the effective focal length f1 of the first lens is 91.15 mm, the effective focal length f2 of the second lens is 231.13 mm, the effective focal length f3 of the third lens is 1220.79 mm, the combined focal length F2 of the reflective polarizing element, quarter-wave plate, and second lens is 35.65 mm, the total effective focal length f of the visual optical system is 28.72 mm, the distance TTL from the first side of the first lens to the display screen of the visual optical system on the optical axis is 27.20 mm, half the diagonal length ImgH of the effective pixel area on the display screen of the visual optical system is 23.03 mm, half the maximum field of view (Semi-FOV) of the visual optical system is 53.00°, and the aperture number FNO of the visual optical system is 5.74.

[0085] In Embodiment 1, the second side surface of the second lens E2, the first side surface of the first lens E1, and the second side surface of the third lens E3 are all aspherical surfaces. The surface shape x of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0086]

[0087] Where x is the distance vector from the vertex of the aspherical surface at a height h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 2 below gives the conic coefficient k and higher-order coefficients A4, A6, A8 and A4 that can be used for each aspherical mirror in Example 1. 10 .

[0088] Face number A4 A6 A8 A10 k S1 -4.61E-01 9.27E-03 8.57E-03 2.84E-03 0 S2 -2.30E-01 1.53E-01 -2.10E-02 -8.32E-03 0 S6 -7.11E-02 -1.16E-02 8.33E-04 1.27E-04 0 S7 5.90E-01 -3.02E-01 3.98E-02 4.44E-02 0 S8 -1.80E+00 4.45E-01 -9.24E-02 2.25E-02 0

[0089] Table 2

[0090] Figure 2A The on-axis chromatic aberration curve of the visual optical system of Embodiment 1 is shown, which represents the deflection of the focal point of light of different wavelengths after passing through the visual optical system. Figure 2B The astigmatism curves of the visual optical system of Embodiment 1 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 2C The distortion curves of the visual optical system of Embodiment 1 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. According to... Figures 2A to 2C It can be seen that the visual optical system given in Example 1 can achieve good imaging and / or projection quality.

[0091] Example 2

[0092] The following is for reference Figures 3 to 4CA visual optical system according to Embodiment 2 of this application is described. In this embodiment and the following embodiments, for the sake of brevity, some descriptions similar to those in Embodiment 1 will be omitted. Figure 3 It is the visual optical system in Example 2.

[0093] like Figure 3 As shown, the visual optical system includes, from the first side to the second side, the following components in sequence: aperture STO, first lens E1, reflective polarizing element RP, quarter-wave plate QWP, second lens E2, partial reflective element BS (not shown), third lens E3, and display screen S9.

[0094] The first lens E1 has positive optical power, with its first side surface S1 being concave and its second side surface S2 being convex. The second lens E2 has positive optical power, with its first side surface S5 being planar and its second side surface S6 being convex. The third lens E3 has negative optical power, with its first side surface S7 being concave and its second side surface S8 being concave. A quarter-wave plate QWP is attached to the first side surface S5 of the second lens E2. A reflective polarizing element RP is attached to the first side surface of the quarter-wave plate QWP. A partial reflective element BS is attached to the second side surface S6 of the second lens E2.

[0095] In this example, a light source may be provided on the display screen S9. Image light from the display screen S9 sequentially passes through the third lens E3, the second lens E2, and reaches the first side of the quarter-wave plate QWP, where it undergoes a first reflection. The light after the first reflection passes through the quarter-wave plate QWP and reaches the partial reflective element BS on the second side of the second lens E2, where it undergoes a second reflection. The light after the second reflection sequentially passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, and the first lens E1, and is finally projected onto a target object (not shown) in space. For example, when this visual optical system is mounted on an electronic device such as VR, the light after the two reflections is finally projected into the eyes of the user.

[0096] In this example, the effective focal length f1 of the first lens is 94.18 mm, the effective focal length f2 of the second lens is 236.28 mm, the effective focal length f3 of the third lens is -392.71 mm, the combined focal length F2 of the reflective polarizing element, quarter-wave plate, and second lens is 36.42 mm, the total effective focal length f of the visual optical system is 29.56 mm, the distance TTL from the first side of the first lens to the display screen of the visual optical system on the optical axis is 27.58 mm, half the diagonal length ImgH of the effective pixel area on the display screen of the visual optical system is 23.42 mm, half the maximum field of view (Semi-FOV) of the visual optical system is 53.00°, and the aperture number FNO of the visual optical system is 5.91.

[0097] Table 3 shows the basic parameters of the visual optical system of Example 2, where the units for radius of curvature and thickness / distance are millimeters (mm). Table 4 shows the conic coefficients and higher-order coefficients that can be used for each aspherical mirror in Example 2, where each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0098]

[0099]

[0100] Table 3

[0101] Face number A4 A6 A8 A10 k S1 -3.02E-01 2.62E-02 -4.19E-03 -1.67E-04 0 S2 -2.11E-01 1.50E-01 -4.06E-03 -4.46E-03 0 S6 -9.68E-02 -1.24E-02 2.01E-03 -8.27E-05 0 S7 2.38E+00 -6.85E-01 2.25E-01 -2.30E-02 0 S8 -4.33E+00 1.03E+00 -3.19E-01 6.99E-02 0

[0102] Table 4

[0103] Figure 4A The on-axis chromatic aberration curve of the visual optical system of Embodiment 2 is shown, which represents the deflection of the focal point of light of different wavelengths after passing through the visual optical system. Figure 4B The astigmatism curves of the visual optical system of Embodiment 2 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 4C The distortion curves of the visual optical system of Embodiment 2 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. According to... Figures 4A to 4C It can be seen that the visual optical system given in Example 2 can achieve good imaging and / or projection quality.

[0104] Example 3

[0105] The following is for reference Figures 5 to 6C A visual optical system according to Embodiment 3 of this application is described. Figure 5 It is the visual optical system in Example 3.

[0106] like Figure 5 As shown, the visual optical system includes, from the first side to the second side, the following components in sequence: aperture STO, first lens E1, reflective polarizing element RP, quarter-wave plate QWP, second lens E2, partial reflective element BS (not shown), third lens E3, and display screen S9.

[0107] The first lens E1 has positive optical power, with its first side surface S1 being concave and its second side surface S2 being convex. The second lens E2 has positive optical power, with its first side surface S5 being planar and its second side surface S6 being convex. The third lens E3 has positive optical power, with its first side surface S7 being convex and its second side surface S8 being concave. A quarter-wave plate QWP is attached to the first side surface S5 of the second lens E2. A reflective polarizing element RP is attached to the first side surface of the quarter-wave plate QWP. A partial reflective element BS is attached to the second side surface S6 of the second lens E2.

[0108] In this example, a light source may be provided on the display screen S9. Image light from the display screen S9 sequentially passes through the third lens E3, the second lens E2, and reaches the first side of the quarter-wave plate QWP, where it undergoes a first reflection. The light after the first reflection passes through the quarter-wave plate QWP and reaches the partial reflective element BS on the second side of the second lens E2, where it undergoes a second reflection. The light after the second reflection sequentially passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, and the first lens E1, and is finally projected onto a target object (not shown) in space. For example, when this visual optical system is mounted on an electronic device such as VR, the light after the two reflections is finally projected into the eyes of the user.

[0109] In this example, the effective focal length f1 of the first lens is 170.26 mm, the effective focal length f2 of the second lens is 212.83 mm, the effective focal length f3 of the third lens is 267.50 mm, the combined focal length F2 of the reflective polarizing element, quarter-wave plate, and second lens is 33.66 mm, the total effective focal length f of the visual optical system is 28.00 mm, the distance TTL from the first side of the first lens to the display screen of the visual optical system on the optical axis is 30.00 mm, half the diagonal length ImgH of the effective pixel area on the display screen of the visual optical system is 23.17 mm, half the maximum field of view (Semi-FOV) of the visual optical system is 53.00°, and the aperture number FNO of the visual optical system is 5.60.

[0110] Table 5 shows the basic parameters of the visual optical system of Example 3, where the units for radius of curvature and thickness / distance are millimeters (mm). Table 6 shows the conic coefficients and higher-order coefficients that can be used for each aspherical mirror in Example 3, where each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0111]

[0112] Table 5

[0113]

[0114]

[0115] Table 6

[0116] Figure 6A The on-axis chromatic aberration curve of the visual optical system of Embodiment 3 is shown, which represents the deflection of the focal point of light of different wavelengths after passing through the visual optical system. Figure 6BThe astigmatism curves of the visual optical system of Embodiment 3 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 6C The distortion curves of the visual optical system of Embodiment 3 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. According to... Figures 6A to 6C It can be seen that the visual optical system given in Example 3 can achieve good imaging and / or projection quality.

[0117] Example 4

[0118] The following is for reference Figures 7 to 8C A visual optical system according to Embodiment 4 of this application is described. Figure 7 It is the visual optical system in Example 4.

[0119] like Figure 7 As shown, the visual optical system includes, from the first side to the second side, the following components in sequence: aperture STO, first lens E1, reflective polarizing element RP, quarter-wave plate QWP, second lens E2, partial reflective element BS (not shown), third lens E3, and display screen S9.

[0120] The first lens E1 has positive optical power, with its first side surface S1 being concave and its second side surface S2 being convex. The second lens E2 has positive optical power, with its first side surface S5 being planar and its second side surface S6 being convex. The third lens E3 has positive optical power, with its first side surface S7 being convex and its second side surface S8 being concave. A quarter-wave plate QWP is attached to the first side surface S5 of the second lens E2. A reflective polarizing element RP is attached to the first side surface of the quarter-wave plate QWP. A partial reflective element BS is attached to the second side surface S6 of the second lens E2.

[0121] In this example, a light source may be provided on the display screen S9. Image light from the display screen S9 sequentially passes through the third lens E3, the second lens E2, and reaches the first side of the quarter-wave plate QWP, where it undergoes a first reflection. The light after the first reflection passes through the quarter-wave plate QWP and reaches the partial reflective element BS on the second side of the second lens E2, where it undergoes a second reflection. The light after the second reflection sequentially passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, and the first lens E1, and is finally projected onto a target object (not shown) in space. For example, when this visual optical system is mounted on an electronic device such as VR, the light after the two reflections is finally projected into the eyes of the user.

[0122] In this example, the effective focal length f1 of the first lens is 90.49 mm, the effective focal length f2 of the second lens is 231.98 mm, the effective focal length f3 of the third lens is 1328.61 mm, the combined focal length F2 of the reflective polarizing element, quarter-wave plate, and second lens is 35.32 mm, the total effective focal length f of the visual optical system is 28.00 mm, the distance TTL from the first side of the first lens to the display screen of the visual optical system on the optical axis is 28.90 mm, half the diagonal length ImgH of the effective pixel area on the display screen of the visual optical system is 22.62 mm, half the maximum field of view (Semi-FOV) of the visual optical system is 53.00°, and the aperture number FNO of the visual optical system is 5.60.

[0123] Table 7 shows the basic parameters of the visual optical system of Example 4, where the units for radius of curvature and thickness / distance are millimeters (mm). Table 8 shows the conic coefficients and higher-order coefficients that can be used for each aspherical mirror in Example 4, where each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0124]

[0125] Table 7

[0126] Face number A4 A6 A8 A10 k S1 -1.65E-01 4.50E-02 -2.54E-03 -1.20E-03 0 S2 1.41E+00 6.93E-01 -1.44E-01 -7.73E-03 0 S6 1.60E-02 -1.92E-02 2.92E-03 -9.66E-05 0 S7 4.33E-01 -3.92E-01 9.94E-02 4.34E-02 0 S8 4.62E-01 2.11E-01 -3.03E-02 -6.12E-02 0

[0127] Table 8

[0128] Figure 8A The on-axis chromatic aberration curve of the visual optical system of Embodiment 4 is shown, which represents the deflection of the focal point of light of different wavelengths after passing through the visual optical system. Figure 8B The astigmatism curves of the visual optical system of Embodiment 4 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 8C The distortion curves of the visual optical system of Example 4 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. According to... Figures 8A to 8C It can be seen that the visual optical system given in Example 4 can achieve good imaging and / or projection quality.

[0129] Example 5

[0130] The following is for reference Figures 9 to 10C A visual optical system according to Embodiment 5 of this application is described. Figure 9 It is the visual optical system in Example 5.

[0131] like Figure 9As shown, the visual optical system includes, from the first side to the second side, the following components in sequence: aperture STO, first lens E1, reflective polarizing element RP, quarter-wave plate QWP, second lens E2, partial reflective element BS (not shown), third lens E3, and display screen S9.

[0132] The first lens E1 has positive optical power, with its first side surface S1 being concave and its second side surface S2 being convex. The second lens E2 has positive optical power, with its first side surface S5 being planar and its second side surface S6 being convex. The third lens E3 has positive optical power, with its first side surface S7 being convex and its second side surface S8 being concave. A quarter-wave plate QWP is attached to the first side surface S5 of the second lens E2. A reflective polarizing element RP is attached to the first side surface of the quarter-wave plate QWP. A partial reflective element BS is attached to the second side surface S6 of the second lens E2.

[0133] In this example, a light source may be provided on the display screen S9. Image light from the display screen S9 sequentially passes through the third lens E3, the second lens E2, and reaches the first side of the quarter-wave plate QWP, where it undergoes a first reflection. The light after the first reflection passes through the quarter-wave plate QWP and reaches the partial reflective element BS on the second side of the second lens E2, where it undergoes a second reflection. The light after the second reflection sequentially passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, and the first lens E1, and is finally projected onto a target object (not shown) in space. For example, when this visual optical system is mounted on an electronic device such as VR, the light after the two reflections is finally projected into the eyes of the user.

[0134] In this example, the effective focal length f1 of the first lens is 109.56 mm, the effective focal length f2 of the second lens is 248.22 mm, the effective focal length f3 of the third lens is 291.32 mm, the combined focal length F2 of the reflective polarizing element, quarter-wave plate, and second lens is 36.98 mm, the total effective focal length f of the visual optical system is 28.00 mm, the distance TTL from the first side of the first lens to the display screen of the visual optical system on the optical axis is 30.00 mm, half the diagonal length ImgH of the effective pixel area on the display screen of the visual optical system is 22.90 mm, half the maximum field of view (Semi-FOV) of the visual optical system is 53.00°, and the aperture number FNO of the visual optical system is 5.60.

[0135] Table 9 shows the basic parameters of the visual optical system of Example 5, where the units for radius of curvature and thickness / distance are millimeters (mm). Table 10 shows the conic coefficients and higher-order coefficients that can be used for each aspherical mirror in Example 5, where each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0136]

[0137] Table 9

[0138] Face number A4 A6 A8 A10 k S1 6.49E-03 -2.71E-04 -4.30E-04 -4.35E-04 0 S2 1.60E+00 3.17E-01 -6.27E-02 -1.81E-02 0 S6 -7.79E-02 -9.91E-03 1.42E-03 -8.04E-05 0 S7 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0 S8 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0

[0139] Table 10

[0140] Figure 10A The on-axis chromatic aberration curve of the visual optical system of Embodiment 5 is shown, which represents the deflection of the focal point of light of different wavelengths after passing through the visual optical system. Figure 10B The astigmatism curves of the visual optical system of Embodiment 5 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 10C The distortion curves of the visual optical system of Example 5 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. According to... Figures 10A to 10C It can be seen that the visual optical system given in Example 5 can achieve good imaging and / or projection quality.

[0141] Example 6

[0142] The following is for reference Figures 11 to 12C A visual optical system according to Embodiment 6 of this application is described. Figure 11 It is the visual optical system in Example 6.

[0143] like Figure 11 As shown, the visual optical system includes, from the first side to the second side, the following components in sequence: aperture STO, first lens E1, reflective polarizing element RP, quarter-wave plate QWP, second lens E2, partial reflective element BS (not shown), third lens E3, and display screen S9.

[0144] The first lens E1 has positive optical power, with its first side surface S1 being concave and its second side surface S2 being convex. The second lens E2 has positive optical power, with its first side surface S5 being planar and its second side surface S6 being convex. The third lens E3 has positive optical power, with its first side surface S7 being concave and its second side surface S8 being convex. A quarter-wave plate QWP is attached to the first side surface S5 of the second lens E2. A reflective polarizing element RP is attached to the first side surface of the quarter-wave plate QWP. A partial reflective element BS is attached to the second side surface S6 of the second lens E2.

[0145] In this example, a light source may be provided on the display screen S9. Image light from the display screen S9 sequentially passes through the third lens E3, the second lens E2, and reaches the first side of the quarter-wave plate QWP, where it undergoes a first reflection. The light after the first reflection passes through the quarter-wave plate QWP and reaches the partial reflective element BS on the second side of the second lens E2, where it undergoes a second reflection. The light after the second reflection sequentially passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, and the first lens E1, and is finally projected onto a target object (not shown) in space. For example, when this visual optical system is mounted on an electronic device such as VR, the light after the two reflections is finally projected into the eyes of the user.

[0146] In this example, the effective focal length f1 of the first lens is 89.77 mm, the effective focal length f2 of the second lens is 233.55 mm, the effective focal length f3 of the third lens is 496.01 mm, the combined focal length F2 of the reflective polarizing element, quarter-wave plate, and second lens is 35.95 mm, the total effective focal length f of the visual optical system is 29.44 mm, the distance TTL from the first side of the first lens to the display screen of the visual optical system on the optical axis is 29.43 mm, half the diagonal length ImgH of the effective pixel area on the display screen of the visual optical system is 23.83 mm, half the maximum field of view (Semi-FOV) of the visual optical system is 53.00°, and the aperture number FNO of the visual optical system is 5.89.

[0147] Table 11 shows the basic parameters of the visual optical system of Example 6, where the units for radius of curvature and thickness / distance are millimeters (mm). Table 12 shows the conic coefficients and higher-order coefficients that can be used for each aspherical mirror in Example 6, where each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0148]

[0149] Table 11

[0150] Face number A4 A6 A8 A10 k S1 3.01E-01 -4.88E-02 8.36E-03 -1.35E-03 0 S2 1.35E-01 5.54E-02 -1.04E-02 -5.73E-03 0 S6 2.35E-02 -9.41E-03 -4.71E-04 2.56E-04 0 S7 -1.24E-01 -4.11E-02 7.79E-03 1.58E-02 0 S8 -1.24E-01 -4.11E-02 7.79E-03 1.58E-02 0

[0151] Table 12

[0152] Figure 12A The on-axis chromatic aberration curve of the visual optical system of Embodiment 6 is shown, which represents the deflection of the focal point after light of different wavelengths passes through the visual optical system. Figure 12B The astigmatism curves of the visual optical system of Embodiment 6 are shown, representing the meridional image plane curvature and the sagittal image plane curvature. Figure 12CThe distortion curves of the visual optical system of Example 6 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. According to... Figures 12A to 12C It can be seen that the visual optical system given in Example 6 can achieve good imaging and / or projection quality.

[0153] In summary, Examples 1 to 6 can satisfy the relationships shown in Table 13.

[0154] Conditional / Example 1 2 3 4 5 6 f1 / R2 / (F2 / R4) 8.02 8.98 6.67 6.60 8.70 6.33 F2 / f 1.24 1.23 1.20 1.26 1.32 1.22 (f1+F2) / f 4.42 4.42 7.28 4.49 5.23 4.27 (R⁴+R²) / (R⁴-R²) 1.94 1.81 7.29 2.27 2.03 2.30 V2 / V3 1.17 1.13 0.93 1.07 1.00 2.55 V1 / V3 1.17 1.13 0.86 1.07 0.99 2.48 TTL / CT2 1.60 1.58 2.71 1.95 2.61 1.73 R4 / (CT2+ET2) -3.87 -3.84 -6.17 -4.44 -6.38 -3.89 FNO×TAN(Semi-FOV) 7.62 7.85 7.43 7.43 7.43 7.81 (DT21+DT22) / (DT11+DT12) 1.28 1.34 1.22 1.20 1.29 1.18 (SAG11+SAG12) / SAG22 2.56 2.67 1.03 2.06 1.82 2.01 (SAG31+SAG32) / f3 0.41 2.82 1.86 0.16 0.65 -0.41 BFL / (CT1+CT3) 0.13 0.15 1.50 0.36 1.21 0.11 SAG22 / SAG12 0.47 0.48 1.11 0.49 0.68 0.48 ET2 / ET1 20.33 21.05 12.55 17.79 12.52 10.84 f2 / CT2 13.59 13.54 19.21 15.62 21.56 13.74

[0155] Table 13

[0156] This application also provides an optical device, which can be a stand-alone projection device such as a projector, or a projection module integrated into a mobile electronic device such as a VR device. This optical device is equipped with the visual optical system described above.

[0157] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A visual optical system, characterized in that, Along the optical axis, from the first side to the second side, the following are included in sequence: A first lens with positive optical power has a concave surface on its first side near the optical axis and a convex surface on its second side near the optical axis. Reflective polarizing element; quarter wave plate; A second lens with positive optical power has a first side surface that is flat and a second side surface that is convex in the near-optical axis region. A partial reflective element is disposed on the second side of the second lens; and A third lens with optical power; The quarter-wave plate is disposed on the first side of the second lens, and the reflective polarizing element is disposed on the first side of the quarter-wave plate. The first side is the side closer to the user's eyes, and the second side is the side closer to the display screen; The visual optical system satisfies: 6.33≤f1 / R2 / (F2 / R4)≤8.98 and 13.54≤f2 / CT2≤21.56, where f1 is the effective focal length of the first lens, R2 is the radius of curvature of the second side of the first lens, F2 is the combined focal length of the reflective polarizing element, the quarter-wave plate, and the second lens, R4 is the radius of curvature of the second side of the second lens, f2 is the effective focal length of the second lens, and CT2 is the center thickness of the second lens on the optical axis. The number of lenses with optical power in the visual optical system is three.

2. The visual optical system according to claim 1, characterized in that, The visual optical system satisfies: 1.81≤(R4+R2) / (R4-R2)≤7.29, where R2 is the radius of curvature of the second side surface of the first lens and R4 is the radius of curvature of the second side surface of the second lens.

3. The visual optical system according to claim 1, characterized in that, The third lens has positive optical power, and the radii of curvature of its first and second sides have the same positive and negative properties.

4. The visual optical system according to claim 1, characterized in that, The visual optical system satisfies: -6.38≤R4 / (CT2+ET2)≤-3.84, where R4 is the radius of curvature of the second side surface of the second lens, CT2 is the center thickness of the second lens on the optical axis, and ET2 is the edge thickness at the maximum effective radius of the second lens.

5. The visual optical system according to claim 1, characterized in that, The visual optical system satisfies: 1.18≤(DT21+DT22) / (DT11+DT12)≤1.34, where DT11 is the effective half-aperture of the first side of the first lens, DT12 is the effective half-aperture of the second side of the first lens, DT21 is the effective half-aperture of the first side of the second lens, and DT22 is the effective half-aperture of the second side of the second lens.

6. The visual optical system according to claim 1, characterized in that, The visual optical system satisfies: 1.03≤(SAG11+SAG12) / SAG22≤2.67, where SAG11 is the distance from the intersection of the first side surface of the first lens on the optical axis to the effective radial vertex of the first side surface of the first lens on the optical axis, SAG12 is the distance from the intersection of the second side surface of the first lens on the optical axis to the effective radial vertex of the second side surface of the first lens on the optical axis, and SAG22 is the distance from the intersection of the second side surface of the second lens on the optical axis to the effective radial vertex of the second side surface of the second lens on the optical axis.

7. The visual optical system according to claim 1, characterized in that, The visual optical system satisfies: 10.84≤ET2 / ET1≤21.05, where ET2 is the edge thickness at the maximum effective radius of the second lens, and ET1 is the edge thickness at the maximum effective radius of the first lens.

8. The visual optical system according to claim 1, characterized in that, The visual optical system satisfies: 0.11≤BFL / (CT1+CT3)≤1.5, where BFL is the distance from the second side of the third lens to the display screen of the visual optical system on the optical axis, CT1 is the center thickness of the first lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

9. The visual optical system according to claim 1, characterized in that, The visual optical system satisfies: 0.47≤SAG22 / SAG12≤1.11, where SAG12 is the distance from the intersection of the second side surface of the first lens on the optical axis to the effective radial vertex of the second side surface of the first lens on the optical axis, and SAG22 is the distance from the intersection of the second side surface of the second lens on the optical axis to the effective radial vertex of the second side surface of the second lens on the optical axis.

10. The visual optical system according to claim 1, characterized in that, The visual optical system satisfies: 0.93≤V2 / V3≤2.55, where V2 is the Abbe number of the second lens and V3 is the Abbe number of the third lens.

11. The visual optical system according to claim 1, characterized in that, The visual optical system satisfies: 0.86≤V1 / V3≤2.48, where V1 is the Abbe number of the first lens and V3 is the Abbe number of the third lens.

12. The visual optical system according to any one of claims 1-11, characterized in that, The visual optical system satisfies: 1.20≤F2 / f≤1.32, where F2 is the combined focal length of the reflective polarizing element, the quarter-wave plate, and the second lens, and f is the total effective focal length of the visual optical system.

13. The visual optical system according to any one of claims 1-11, characterized in that, The visual optical system satisfies: 4.27≤(f1+F2) / f≤7.28, where f1 is the effective focal length of the first lens, F2 is the combined focal length of the reflective polarizing element, the quarter-wave plate and the second lens, and f is the total effective focal length of the visual optical system.

14. The visual optical system according to any one of claims 1-11, characterized in that, The visual optical system satisfies: 1.58≤TTL / CT2≤2.71, where TTL is the distance from the first side of the first lens to the display screen of the visual optical system on the optical axis, and CT2 is the center thickness of the second lens on the optical axis.

15. The visual optical system according to any one of claims 1-11, characterized in that, The visual optical system satisfies: 7.43≤FNO×TAN(Semi-FOV)≤7.85, where FNO is the aperture number of the visual optical system and Semi-FOV is half of the maximum field of view of the visual optical system.

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