Visual optical system and VR device comprising the same

Abstract

The application discloses a visual optical system, which comprises a lens barrel and a first lens group, a second lens and a third lens arranged in sequence from a first side to a second side along an optical axis and accommodated in the lens barrel, wherein the first lens group comprises a first lens, a reflective polarizing element and a quarter-wave plate; a first spacing element is arranged between the first lens and the second lens, and a first side surface of the first spacing element is at least partially in contact with a second side surface of the first lens; a second spacing element is arranged between the second lens and the third lens, and a first side surface of the second spacing element is at least partially in contact with a second side surface of the second lens. The combined focal length f23 of the second lens and the third lens, the refractive index N3 of the third lens and the distance EP12 of the first spacing element to the second spacing element along a direction parallel to the optical axis satisfy the following formula: 3.5 < f23 / (N3 x EP12) < 26.0.

Description

Technical Field

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

[0002] In recent years, the metaverse field has been developing rapidly. The metaverse refers to a virtual space built upon the real world, where users engage in social and spiritual activities such as culture, social interaction, and entertainment. With the rapid development of the metaverse, augmented reality (AR) and virtual reality (VR) technologies, as entry points for human-computer interaction, have received considerable attention. Among visual display devices, virtual reality (VR) technology is becoming increasingly mature, especially the catadioptric optical system structure, which is gaining increasing consumer anticipation due to its ability to significantly reduce device thickness.

[0003] However, limited by current coating technology, the curvature of optical systems has low degrees of freedom, and the performance improvement potential of conventional structural systems is limited. This often results in a series of problems such as large aberrations, high sensitivity, difficult molding, poor assembly stability, and low yield, severely affecting and restricting the improvement of optical system quality. Therefore, how to comprehensively consider all components of an optical system, including lenses, spacers, and lens barrels, to further improve and optimize the design of structures and parameters, and to control and mitigate these problems as much as possible to effectively improve system performance, is one of the technical problems that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] This application provides a visual optical system, which may include a lens barrel and a first lens group, a second lens, and a third lens arranged sequentially along the optical axis from a first side to a second side, housed within the lens barrel. The first lens group includes a first lens, a reflective polarizing element, and a quarter-wave plate. A first spacer element is provided between the first lens and the second lens, with a first side of the first spacer element at least partially contacting a second side of the first lens. A second spacer element is provided between the second lens and the third lens, with a first side of the second spacer element at least partially contacting a second side of the second lens. The combined focal length f23 of the second lens and the third lens, the refractive index N3 of the third lens, and the distance EP12 between the first spacer element and the second spacer element along a direction parallel to the optical axis can satisfy: 3.5. <f23 / (N3×EP12)<26.0。

[0005] In one embodiment, the first lens or the second lens has a partial reflective layer.

[0006] In one embodiment, the first side of the reflective polarizing element is attached to the second side of the first lens, and the first side of the quarter-wave plate is attached to the second side of the reflective polarizing element.

[0007] In one embodiment, the second side of the reflective polarizing element is attached to the first side of the quarter-wave plate, and the second side of the quarter-wave plate is attached to the first side of the first lens.

[0008] In one embodiment, the radius of curvature R4 of the second side surface of the second lens, the inner diameter d2s of the first side surface of the second spacer element, the outer diameter D2m of the second side surface of the second spacer element, and the radius of curvature R5 of the first side surface of the third lens can satisfy: -4 <R4 / d2s+D2m / R5<7。

[0009] In one embodiment, the maximum height L of the lens barrel along the optical axis, the center thickness CT2 of the second lens on the optical axis, and the air gap T23 between the second and third lenses on the optical axis can satisfy: 2.0 <L / (CT2+T23)<5.0。

[0010] In one embodiment, the inner diameter d0s of the first side end face of the lens barrel, the distance EP01 from the first side end face of the lens barrel to the first side surface of the first spacer element along the direction parallel to the optical axis, the inner diameter d0m of the second side end face of the lens barrel, and the effective focal length f of the visual optical system can satisfy: 13 <d0s / EP01+d0m / f<24。

[0011] In one embodiment, the radius of curvature R5 of the first side surface of the third lens, the radius of curvature R6 of the second side surface of the third lens, the inner diameter d0m of the second side end face of the lens barrel, and the inner diameter d0s of the first side end face of the lens barrel can satisfy: 8.0<(R5+R6) / |d0m-d0s|<20.0.

[0012] In one embodiment, the Abbe number V2 of the second lens, the Abbe number V3 of the third lens, the center thickness CT2 of the second lens on the optical axis, the distance EP12 between the first spacer element and the second spacer element along a direction parallel to the optical axis, and the combined focal length FG12 of the first lens, the reflective polarizing element, the quarter-wave plate and the second lens can satisfy: 33 < (V2 + V3) × (CT2 + EP12) / FG12 < 78.

[0013] In one embodiment, the distance TD between the first side surface of the first lens and the second side surface of the third lens on the optical axis and the distance EP12 between the first spacer element and the second spacer element along a direction parallel to the optical axis can satisfy: 1 <TD / EP12<9。

[0014] In one embodiment, the outer diameter D2s of the first side of the second spacer element, the inner diameter d2s of the first side of the second spacer element, the axial distance SAG31 from the intersection of the first side of the third lens and the optical axis to the vertex of the effective radius of the first side of the third lens, and the axial distance SAG32 from the intersection of the second side of the third lens and the optical axis to the vertex of the effective radius of the second side of the third lens can satisfy: -5 < (D2s - d2s) / (SAG31 - SAG32) < 2.5.

[0015] In one embodiment, the outer diameter D2s of the first side of the second spacer element, the inner diameter d2m of the second side of the second spacer element, the center thickness CT2 of the second lens on the optical axis, and the center thickness CT1 of the first lens on the optical axis can satisfy: 1.0 < (D2s-d2m) / (CT2-CT1) < 5.5.

[0016] In one embodiment, the effective focal length f of the visual optical system, the outer diameter D1m of the second side of the first spacer element, and the inner diameter d1m of the second side of the first spacer element can satisfy: 1 <f / (D1m-d1m)<7。

[0017] In one embodiment, the maximum height L of the lens barrel along the optical axis, the outer diameter D0m of the second side end face of the lens barrel, and the outer diameter D0s of the first side end face of the lens barrel can satisfy: 4.0 <L / |D0m-D0s|<13.0。

[0018] On the other hand, this application also provides a VR device, which includes a visual optical system provided by at least one embodiment of the above-described embodiments, wherein the first side is the human eye side and the second side is the display side.

[0019] The visual optical system disclosed in the present application includes a first lens group, a second lens, and a third lens sequentially arranged along the optical axis from the first side to the second side and accommodated in a lens barrel. The first lens group includes a first lens, a reflective polarizing element, and a quarter-wave plate. It also includes a plurality of spacer elements disposed between adjacent lenses. At least a first spacer element in contact with the first lens is provided between the first lens and the second lens, and at least a second spacer element in contact with the second lens is provided between the second lens and the third lens. At the same time, by controlling the combined focal length f23 of the second lens and the third lens, the refractive index N3 of the third lens, and the distance EP12 along the optical axis from the first spacer element to the second spacer element to satisfy the conditional formula 3.5 < f23 / (N3 × EP12) < 26.0, the optical powers of the second lens and the third lens can be reasonably distributed, the contribution of the aberrations of the two lenses can be controlled, balanced with the aberrations generated by other optical elements, and the system aberrations can be kept at a reasonable level. The edge thicknesses of the third lens and the first lens can be reasonably controlled to achieve the best molding structure and assembly stability within a certain range, which is beneficial to effectively improving the system performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] With reference to the accompanying drawings, through the following detailed description of non-limiting embodiments, other features, objects, and advantages of the present application will become more apparent. In the drawings:

[0021] Figure 1 、 Figure 2 and Figure 3 respectively show schematic structural diagrams of the visual optical system according to Embodiment 1 of the present application under three embodiments;

[0022] Figure 4 、 Figure 5 and Figure 6 respectively show the axial chromatic aberration curve, astigmatism curve, and distortion curve of the visual optical system of Embodiment 1;

[0023] Figure 7 、 Figure 8 and Figure 9 respectively show schematic structural diagrams of the visual optical system according to Embodiment 2 of the present application under three embodiments;

[0024] Figure 10 、<000(0068>and Figure 12 respectively show the axial chromatic aberration curve, astigmatism curve, and distortion curve of the visual optical system of Embodiment 2; ​​​​​​​​

[0026] Figure 16 , Figure 17 and Figure 18 The on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the visual optical system of Example 3 are shown respectively; and

[0027] Figure 19 A schematic diagram showing the structure and some parameters of a visual optical system according to an exemplary embodiment of this application is shown. Detailed Implementation

[0028] 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.

[0029] 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.

[0030] 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.

[0031] In this paper, the paraxial 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 paraxial 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 paraxial region.

[0032] 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.

[0033] 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 a 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.

[0034] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. The following embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this application. It should be pointed out that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] The features, principles and other aspects of this application are described in detail below.

[0036] A visual optical system according to an exemplary embodiment of this application may include a lens barrel and a first lens group, a second lens and a third lens arranged sequentially along the optical axis from a first side to a second side within the lens barrel, wherein the first lens group may include at least a first lens, a reflective polarizing element and a quarter-wave plate.

[0037] In an exemplary embodiment, at least one spacer element may be present between two adjacent lenses. For example, at least a first spacer element may be present between a first lens and a second lens, with a first side of the first spacer element at least partially contacting a second side of the first lens. At least a second spacer element may be present between a second lens and a third lens, with a first side of the second spacer element at least partially contacting a second side of the second lens. In a visual optics system, the surface of each element that is closer to the first side and farther from the second side is the first side of the element, and the surface of each element that is closer to the second side and farther from the first side is the second side of the element.

[0038] In an exemplary embodiment, the first side may be, for example, the human eye side, and the second side may be, for example, the display side. The visual optical system may be used in various VR display devices.

[0039] In an exemplary embodiment, at least one of the first and second lenses may have a partially reflective layer on its first or second side. The provision of a partially reflective layer can increase the light reflection length and improve space utilization.

[0040] In an exemplary embodiment, the first side of the reflective polarizing element may be attached to the second side of the first lens, and the first side of the quarter-wave plate may be attached to the second side of the reflective polarizing element.

[0041] The first side of the reflective polarizing element (the surface away from the display side) is attached to the second side of the first lens (the surface near the display side), and the first side of the quarter-wave plate (the surface away from the display side) is attached to the second side of the reflective polarizing element (the surface near the display side). Utilizing the phase-adding function of the quarter-wave plate and the beam-splitting function of the reflective polarizing element, as well as the fact that at least one of the first and second lenses has a partially reflective layer on its first or second side, a folding effect in the imaging optical path is achieved. Both the reflective polarizing element and the quarter-wave plate are attached to the second side of the first lens, allowing for a composite structure. This single attachment operation achieves the desired structure, eliminating the need for two attachment operations, reducing angular position errors caused by attachment, and improving image quality.

[0042] In an exemplary embodiment, the second side of the reflective polarizing element may be attached to the first side of the quarter-wave plate, and the second side of the quarter-wave plate may be attached to the first side of the first lens.

[0043] The second side of the reflective polarizing element (the surface near the display side) is bonded to the first side of the quarter-wave plate (the surface away from the display side), and the second side of the quarter-wave plate (the surface near the display side) is bonded to the first side of the first lens (the surface away from the display side). Utilizing the phase-adding function of the quarter-wave plate and the beam-splitting function of the reflective polarizing element, as well as the fact that at least one of the first and second lenses has a partially reflective layer on its first or second side, a folding effect in the imaging optical path is achieved. Both the reflective polarizing element and the quarter-wave plate are bonded to the first side of the first lens, allowing for a composite structure. This single bonding operation achieves the desired structure, eliminating the need for two bonding operations, reducing angular position errors caused by bonding, and improving image quality.

[0044] In an exemplary embodiment, the visual optical system of the present application can satisfy the conditional formula 3.5 < f23 / (N3×EP12) < 26.0, where f23 is the combined focal length of the second lens and the third lens, N3 is the refractive index of the third lens, and EP12 is the distance from the first spacer element to the second spacer element along the direction parallel to the optical axis. By controlling the combined focal length of the second lens and the third lens, the refractive index of the third lens, and the distance from the first spacer element to the second spacer element along the direction parallel to the optical axis to satisfy the conditional formula 3.5 < f23 / (N3×EP12) < 26.0, the optical power of the second lens and the third lens can be reasonably distributed, the contribution of the aberrations of the two lenses can be controlled, and the aberrations generated by other optical elements can be balanced, so that the system aberrations are in a reasonable level state; controlling the refractive index of the third lens and the distance from the first spacer element to the second spacer element along the direction parallel to the optical axis can respectively control the edge thicknesses of the third lens and the first lens, so that the best molding structure and assembly stability can be achieved within a certain range.

[0045] In an exemplary embodiment, the visual optical system of the present application can satisfy the conditional formula -4 < R4 / d2s + D2m / R5 < 7, where R4 is the curvature radius of the second side surface of the second lens, d2s is the inner diameter of the first side surface of the second spacer element, D2m is the outer diameter of the second side surface of the second spacer element, and R5 is the curvature radius of the first side surface of the third lens. By controlling the curvature radius of the second side surface of the second lens, the inner diameter of the first side surface of the second spacer element, the outer diameter of the second side surface of the second spacer element, and the curvature radius of the first side surface of the third lens to satisfy the conditional formula -4 < R4 / d2s + D2m / R5 < 7, the curvature radii of the second side surface of the second lens and the first side surface of the third lens are reasonably restricted, which is beneficial to reducing the sensitivity of the second lens and the third lens, thereby improving the assembly yield; secondly, the inner diameter of the first side surface and the outer diameter of the second side surface of the second spacer element can be reasonably restricted to ensure its processability.

[0046] In an exemplary embodiment, the visual optical system of the present application can satisfy the conditional formula 2.0 < L / (CT2 + T23) < 5.0, where L is the maximum height of the lens barrel along the optical axis direction, CT2 is the central thickness of the second lens on the optical axis, and T23 is the air gap between the second lens and the third lens on the optical axis. By controlling the ratio of the maximum height of the lens barrel along the optical axis direction to the sum of the central thickness of the second lens on the optical axis and the air gap between the second and third lenses on the optical axis within this range, it is beneficial to control the shape of the second lens, thereby determining a position favorable for attaching the reflective polarizing element; and it is beneficial to reduce the height of the body, making the entire lens group more compact, which is beneficial to miniaturized design.

[0047] In an exemplary embodiment, the visual optical system of the present application can satisfy the conditional formula 13 < d0s / EP01 + d0m / f < 24, where d0s is the inner diameter of the first side end face of the lens barrel, EP01 is the distance along the optical axis direction from the first side end face of the lens barrel to the first side face of the first spacer element, d0m is the inner diameter of the second side end face of the lens barrel, and f is the effective focal length of the visual optical system. By controlling the sum of the ratio of the inner diameter of the first side end face of the lens barrel to the distance along the optical axis direction from the first side end face of the lens barrel to the first side face of the first spacer element and the ratio of the inner diameter of the second side end face of the lens barrel to the effective focal length of the visual optical system within this range, the external dimensions of the lens barrel can be ensured, which is beneficial for molding; the wall thickness of the first side face of the lens barrel and the mechanical diameter thickness of the first spacer element can also be controlled, which is beneficial for the molding of the lens barrel and the spacer element.

[0048] In an exemplary embodiment, the visual optical system of the present application can satisfy the conditional formula 8.0 < (R5 + R6) / |d0m - d0s| < 20.0, where R5 is the curvature radius of the first side face of the third lens, R6 is the curvature radius of the second side face of the third lens, d0m is the inner diameter of the second side end face of the lens barrel, and d0s is the inner diameter of the first side end face of the lens barrel. By controlling the curvature radius of the first side face of the third lens, the curvature radius of the second side face of the third lens, the inner diameter of the second side end face of the lens barrel, and the inner diameter of the first side end face of the lens barrel to satisfy the conditional formula 8.0 < (R5 + R6) / |d0m - d0s| < 20.0, it is beneficial for correcting off-axis aberrations and improving the overall image quality of the system; the external dimensions of the lens barrel can also be ensured, which is beneficial for molding.

[0049] In an exemplary embodiment, the visual optical system of the present application can satisfy the conditional formula 33 < (V2 + V3)×(CT2 + EP12) / FG12 < 78, where V2 is the Abbe number of the second lens, V3 is the Abbe number of the third lens, CT2 is the central thickness of the second lens on the optical axis, EP12 is the distance along the optical axis direction from the first spacer element to the second spacer element, and FG12 is the combined focal length of the first lens, reflective polarizing element, quarter-wave plate, and the second lens. By controlling the Abbe number of the second lens, the Abbe number of the third lens, the central thickness of the second lens on the optical axis, the distance along the optical axis direction from the first spacer element to the second spacer element, and the combined focal length of the first lens, reflective polarizing element, quarter-wave plate, and the second lens to satisfy the conditional formula 33 < (V2 + V3)×(CT2 + EP12) / FG12 < 78, it is beneficial for correcting the chromatic aberration of the optical system and improving the wearing experience of consumers; it is beneficial for restricting the overall length of the optical system, ensuring the strength of the second lens, and ensuring the assembly stability; and it is beneficial for ensuring the optical performance of the system.

[0050] In an exemplary embodiment, the visual optical system of the present application can satisfy the conditional formula 1<TD / EP12<9, where TD is the distance on the optical axis from the first side surface of the first lens to the second side surface of the third lens, and EP12 is the distance between the first spacer element and the second spacer element in the direction parallel to the optical axis. By controlling the ratio of the distance on the optical axis from the first side surface of the first lens to the second side surface of the third lens to the distance between the first spacer element and the second spacer element in the direction parallel to the optical axis within this range, it is beneficial to control the barrel length and indirectly control the focal length of the system.

[0051] In an exemplary embodiment, the visual optical system of the present application can satisfy the conditional formula -5<(D2s - d2s) / (SAG31 - SAG32)<2.5, where D2s is the outer diameter of the first side surface of the second spacer element, d2s is the inner diameter of the first side surface of the second spacer element, SAG31 is the axial distance from the intersection of the first side surface of the third lens and the optical axis to the vertex of the effective radius of the first side surface of the third lens, and SAG32 is the axial distance from the intersection of the second side surface of the third lens and the optical axis to the vertex of the effective radius of the second side surface of the third lens. By controlling the ratio of the difference between the outer diameter and the inner diameter of the first side surface of the second spacer element to the difference between the axial distance from the intersection of the first side surface of the third lens and the optical axis to the vertex of the effective radius of the first side surface of the third lens and the axial distance from the intersection of the second side surface of the third lens and the optical axis to the vertex of the effective radius of the second side surface of the third lens within this range, on the one hand, it can improve the stray light of the lens, and on the other hand, considering the abutting relationship between the third lens and the second spacer element, it is beneficial to the assembly stability; and it is beneficial to control the optical power of the third lens and is beneficial to correcting the aberration of the VR lens.

[0052] In an exemplary embodiment, the visual optical system of the present application can satisfy the conditional formula 1.0<(D2s - d2m) / (CT2 - CT1)<5.5, where D2s is the outer diameter of the first side surface of the second spacer element, d2m is the inner diameter of the second side surface of the second spacer element, CT2 is the central thickness of the second lens on the optical axis, and CT1 is the central thickness of the first lens on the optical axis. By controlling the ratio of the difference between the outer diameter and the inner diameter of the first side surface of the second spacer element to the difference between the central thickness of the second lens and the central thickness of the first lens on the optical axis within this range, it is beneficial to reduce the body height and is beneficial to the miniaturization of the VR lens.

[0053] In an exemplary embodiment, the visual optical system of the present application can satisfy the conditional formula 1 < f / (D1m - d1m) < 7, where f is the effective focal length of the visual optical system, D1m is the outer diameter of the second side surface of the first spacer element, and d1m is the inner diameter of the second side surface of the first spacer element. By controlling the ratio of the effective focal length of the visual optical system to the difference between the outer diameter of the second side surface of the first spacer element and the inner diameter of the second side surface of the first spacer element within this range, the field angle of the system can be effectively constrained, so that the system meets the characteristics of a large field angle of a VR lens; in addition, the radial thickness of the lens barrel mechanism can be indirectly controlled, which is beneficial to ensuring assembly.

[0054] In an exemplary embodiment, the visual optical system of the present application can satisfy the conditional formula 4.0 < L / |D0m - D0s| < 13.0, where L is the maximum height of the lens barrel along the optical axis, D0m is the outer diameter of the second side end surface of the lens barrel, and D0s is the outer diameter of the first side end surface of the lens barrel. By controlling the maximum height of the lens barrel along the optical axis, the outer diameter of the second side end surface of the lens barrel, and the outer diameter of the first side end surface of the lens barrel to satisfy the conditional formula 4.0 < L / |D0m - D0s| < 13.0, it is beneficial to the stability of the lens barrel forming and assembly.

[0055] In an exemplary embodiment, the visual optical system of the present application may include at least one aperture stop. The aperture stop can constrain the light path and control the light intensity. The aperture stop can be set at an appropriate position of the visual optical system. For example, the aperture stop can be set between the first side (the human eye side) and the first lens.

[0056] In an exemplary embodiment, optionally, the above-mentioned visual optical system may further include a filter for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the imaging surface.

[0057] [[ID=~12]]According to the visual optical system of the above embodiment of the present application, by arranging a first lens group, a second lens, and a third lens accommodated in the lens barrel and arranged in sequence along the optical axis from the first side to the second side, where the first lens group includes a first lens, a reflective polarizing element, and a quarter-wave plate; and arranging at least a first spacer element contacting the first lens between the first lens and the second lens, and at least a second spacer element contacting the second lens between the second lens and the third lens; at the same time, controlling the combined focal length f23 of the second lens and the third lens, the refractive index N3 of the third lens, and the distance EP12 along the optical axis from the first spacer element to the second spacer element to satisfy the conditional formula 3.5 < f23 / (N3 × EP12) < 26.0, the contribution amount of the aberration of the second lens and the third lens can be reasonably controlled, balanced with the aberration generated by other optical elements, and the system aberration can be in a reasonable level state; the edge thicknesses of the third lens and the first lens can be reasonably controlled to achieve the best forming structure and assembly stability within a certain range; it is beneficial to effectively improve the system performance.

[0058] Specific embodiments of the visual optical system applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

[0059] Example 1

[0060] The following is for reference Figure 1 , Figure 2 , Figure 3 as well as Figure 4 , Figure 5 and Figure 6 A visual optical system according to Embodiment 1 of this application is described. Figure 1 , Figure 2 and Figure 3 The diagrams show the structure of the visual optical system according to Embodiment 1 of this application under three different implementations (Implementation 1-1, Implementation 1-2, and Implementation 1-3).

[0061] like Figure 1 , Figure 2 and Figure 3 As shown, the visual optical system includes a lens barrel and, mounted within the lens barrel, sequentially arranged along the optical axis from a first side (eye side) to a second side (display side): a first lens E1, a first spacer element P1, a second lens E2, a second spacer element P2, and a third lens E3. The first side of the first spacer element P1 is in at least partial contact with the second side of the first lens E1. The first side of the second spacer element P2 is in at least partial contact with the second side of the second lens E2.

[0062] In this embodiment, a reflective polarizing element and a quarter-wave plate are sequentially attached to the second side of the first lens E1 from the first side to the second side. That is, the first side of the reflective polarizing element is attached to the second side of the first lens E1, and the first side of the quarter-wave plate is attached to the second side of the reflective polarizing element.

[0063] In this embodiment, the second side of the second lens E2 has a partially reflective layer.

[0064] In this embodiment, the first lens E1 has a first side surface S1 and a second side surface S2. The reflective polarizing element has a first side surface S2 and a second side surface S3. The quarter-wave plate has a first side surface S3 and a second side surface S4. The second lens E2 has a first side surface S5 and a second side surface S6. The third lens E3 has a first side surface S7 and a second side surface S8. Furthermore, in this embodiment, the visual optical system also includes a display located on the second side, which has a surface S9.

[0065] 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).

[0066] surface element Surface type radius of curvature thickness Refractive index Abbe number Refraction / Reflection spherical endless endless refraction STO Stabilizer (STO) spherical endless 15.0000 refraction S1 First lens (E1) aspherical 549.0671 1.0773 1.49 70.4 refraction S2 Reflective polarizing element (RP) spherical 0.0000 0.2000 1.50 57.0 refraction S3 Quarter-wave plate (QWP) spherical 0.0000 0.2000 1.50 57.0 refraction S4 spherical 0.0000 1.7500 refraction S5 Second lens (E2) aspherical 655.9635 5.4397 1.49 70.4 refraction S6 Partial reflective layer (BS) aspherical -118.5162 -5.4397 reflection S5 aspherical 655.9635 -1.7500 refraction S4 Quarter-wave plate (QWP) spherical 0.0000 -0.2000 1.50 57.0 refraction S3 spherical 0.0000 0.2000 reflection S4 spherical 0.0000 1.7500 refraction S5 Second lens (E2) aspherical 655.9635 5.4397 1.49 70.4 refraction S6 aspherical -118.5162 2.8551 refraction S7 Third lens (E3) aspherical 45.7854 8.7311 1.49 70.4 refraction S8 aspherical 91.1570 10.7468 refraction S9 monitor spherical endless refraction

[0067] Table 1

[0068] In Embodiment 1, the first side surface S1 of the first lens E1, the first side surface S5 and the second side surface S6 of the second lens E2, and the first side surface S7 and the second side surface S8 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:

[0069]

[0070] 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 higher-order coefficients A4, A6, A8, A1, A2, A3, A4, A5, A6, A8, A1, A1, A2, A3, A4, A5 ...6, A7, A8, A1, A1, A1, A1, A1, A1, A1, A1, A1, A1, A1, A1, A1, A 10 and A 12 .

[0071] Face number A4 A6 A8 A10 A12 S1 3.1541E+01 -5.1643E-02 2.4539E-02 -3.7175E-03 1.5634E-03 S5 2.7326E+01 3.7806E-01 7.6281E-02 -9.9810E-02 -1.2299E-02 S6 2.9845E+01 -5.8125E-02 1.5137E-01 -8.7095E-02 1.0382E-04 S7 2.2869E+01 -1.7395E+00 2.8152E-01 1.0364E-01 2.0176E-02 S8 2.6465E+01 -2.4240E+00 -1.2244E+00 8.8838E-01 1.0974E-01

[0072] Table 2

[0073] The relevant parameter values ​​in this embodiment are shown in Table 7, combined with... Figure 1 , Figure 2 , Figure 3 as well as Figure 19 Wherein, d1m is the inner diameter of the second side surface of the first spacer element P1; D1m is the outer diameter of the second side surface of the first spacer element P1; d2s is the inner diameter of the first side surface of the second spacer element P2; d2m is the inner diameter of the second side surface of the second spacer element P2; D2s is the outer diameter of the first side surface of the second spacer element P2; D2m is the outer diameter of the second side surface of the second spacer element P2; d0s is the inner diameter of the first side end face of the lens barrel; d0m is the inner diameter of the second side end face of the lens barrel; D0s is the outer diameter of the first side end face of the lens barrel; D0m is the outer diameter of the second side end face of the lens barrel; EP01 is the distance from the first side end face of the lens barrel to the first side surface of the first spacer element P1 along the direction parallel to the optical axis; EP12 is the distance from the first spacer element P1 to the second spacer element P2 along the direction parallel to the optical axis; and L is the maximum height of the lens barrel along the optical axis. The units of all the parameters shown in Table 7 are millimeters (mm).

[0074] Figure 4 The on-axis chromatic aberration curve of the visual optical system of Embodiment 1 is shown, which represents the deviation of the convergence focal point of light of different wavelengths after passing through the lens. Figure 5The 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 6 The distortion curves of the visual optical system of Embodiment 1 are shown, representing the distortion magnitude values ​​corresponding to different image heights. According to... Figures 4 to 6 It can be seen that the visual optical system given in Example 1 can achieve good imaging quality.

[0075] Example 2

[0076] The following is for reference Figure 7 , Figure 8 , Figure 9 as well as Figure 10 , Figure 11 and Figure 12 A 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 7 , Figure 8 and Figure 9 Schematic diagrams of the visual optical system according to Embodiment 2 of this application are shown in three different implementations (Implementation 2-1, Implementation 2-2, and Implementation 2-3).

[0077] like Figure 7 , Figure 8 and Figure 9 As shown, the visual optical system includes a lens barrel and, mounted within the lens barrel, sequentially arranged along the optical axis from a first side (eye side) to a second side (display side): a first lens E1, a first spacer element P1, a second lens E2, a second spacer element P2, and a third lens E3. The first side of the first spacer element P1 is in at least partial contact with the second side of the first lens E1. The first side of the second spacer element P2 is in at least partial contact with the second side of the second lens E2.

[0078] In this embodiment, a reflective polarizing element and a quarter-wave plate are sequentially attached to the first side of the first lens E1 from the first side to the second side. That is, the second side of the reflective polarizing element is attached to the first side of the quarter-wave plate, and the second side of the quarter-wave plate is attached to the first side of the first lens E1.

[0079] In this embodiment, the second side of the first lens E1 has a partially reflective layer.

[0080] In this embodiment, the reflective polarizing element has a first side surface S1 and a second side surface S2. The quarter-wave plate has a first side surface S2 and a second side surface S3. The first lens E1 has a first side surface S3 and a second side surface S4. The second lens E2 has a first side surface S5 and a second side surface S6. The third lens E3 has a first side surface S7 and a second side surface S8. Furthermore, in this embodiment, the visual optical system also includes a display located on the second side, which has a surface S9.

[0081] 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 higher-order coefficients A4, A6, A8, and A6 that can be used for the aspherical mirrors S4 to S8 in Example 2. 10 and A 12 Each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0082] surface element Surface type radius of curvature thickness Refractive index Abbe number Refraction / Reflection spherical endless endless refraction STO Stabilizer (STO) spherical endless 15.0000 refraction S1 Reflective polarizing element (RP) spherical 0.0000 0.2000 1.50 57.0 refraction S2 Quarter-wave plate (QWP) spherical 0.0000 0.2000 1.50 57.0 refraction S3 First lens (E1) spherical 0.0000 3.2669 1.49 70.4 refraction S4 Partial reflective layer (BS) aspherical -115.6172 -3.2669 reflection S3 Quarter-wave plate (QWP) spherical 0.0000 -0.2000 1.50 57.0 refraction S2 spherical 0.0000 0.2000 reflection S3 First lens (E1) spherical 0.0000 3.2669 1.49 70.4 refraction S4 aspherical -115.6172 0.9879 refraction S5 Second lens (E2) aspherical 76.1904 4.8802 1.49 70.4 refraction S6 aspherical 256.4662 0.7549 refraction S7 Third lens (E3) aspherical 35.7269 5.2793 1.49 70.4 refraction S8 aspherical 71.8880 15.4308 refraction S9 monitor spherical endless refraction

[0083] Table 3

[0084] Face number A4 A6 A8 A10 A12 S4 2.9652E+01 1.1643E-01 9.4089E-02 -3.3439E-02 -3.6244E-02 S5 2.9925E+01 -8.6535E-01 -9.3872E-01 -8.1909E-01 -2.1812E-01 S6 2.7964E+01 -4.0841E+00 -1.7746E+00 -4.0432E-02 -4.3952E-01 S7 4.7125E+01 9.1219E-01 -1.5715E+00 -2.9776E+00 -9.0556E-01 S8 2.4406E+01 -8.5442E-01 -1.4073E+00 3.3137E-01 1.8678E-01

[0085] Table 4

[0086] The relevant parameter values ​​in Example 2 are shown in Table 7. The meaning of each parameter is as described above and will not be repeated here. The unit of each parameter in Table 7 is millimeters (mm).

[0087] Figure 10 The on-axis chromatic aberration curve of the visual optical system of Embodiment 2 is shown, which represents the deviation of the convergence focal point of light of different wavelengths after passing through the lens. Figure 11 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 12 The distortion curves of the visual optical system of Embodiment 2 are shown, representing the distortion magnitude values ​​corresponding to different image heights. According to... Figures 10 to 12 It can be seen that the visual optical system given in Example 2 can achieve good imaging quality.

[0088] Example 3

[0089] The following is for reference Figure 13 , Figure 14 , Figure 15 as well as Figure 16 , Figure 17 and Figure 18 A visual optical system according to Embodiment 3 of this application is described. Figure 13 , Figure 14 and Figure 15Schematic diagrams of the visual optical system according to Embodiment 3 of this application are shown in three different implementations (Implementation 3-1, Implementation 3-2, and Implementation 3-3).

[0090] like Figure 13 , Figure 14 and Figure 15 As shown, the visual optical system includes a lens barrel and, mounted within the lens barrel, sequentially arranged along the optical axis from a first side (eye side) to a second side (display side): a first lens E1, a first spacer element P1, a second lens E2, a second spacer element P2, and a third lens E3. The first side of the first spacer element P1 is in at least partial contact with the second side of the first lens E1. The first side of the second spacer element P2 is in at least partial contact with the second side of the second lens E2.

[0091] In this embodiment, a reflective polarizing element and a quarter-wave plate are sequentially attached to the first side of the first lens E1 from the first side to the second side. That is, the second side of the reflective polarizing element is attached to the first side of the quarter-wave plate, and the second side of the quarter-wave plate is attached to the first side of the first lens E1.

[0092] In this embodiment, the second side of the first lens E1 has a partially reflective layer.

[0093] In this embodiment, the reflective polarizing element has a first side surface S1 and a second side surface S2. The quarter-wave plate has a first side surface S2 and a second side surface S3. The first lens E1 has a first side surface S3 and a second side surface S4. The second lens E2 has a first side surface S5 and a second side surface S6. The third lens E3 has a first side surface S7 and a second side surface S8. Furthermore, in this embodiment, the visual optical system also includes a display located on the second side, which has a surface S9.

[0094] 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 higher-order coefficients A4, A6, A8, and A6 that can be used for each aspherical mirror S4 to S8 in Example 3. 10 and A 12 Each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0095] surface element Surface type radius of curvature thickness Refractive index Abbe number Refraction / Reflection spherical endless endless refraction STO Stabilizer (STO) spherical endless 15.0000 refraction S1 Reflective polarizing element (RP) spherical 0.0000 0.2000 1.50 57.0 refraction S2 Quarter-wave plate (QWP) spherical 0.0000 0.2000 1.50 57.0 refraction S3 First lens (E1) spherical 0.0000 3.0405 1.52 67.0 refraction S4 Partial reflective layer (BS) aspherical -116.2882 -3.0405 reflection S3 Quarter-wave plate (QWP) spherical 0.0000 -0.2000 1.50 57.0 refraction S2 spherical 0.0000 0.2000 reflection S3 First lens (E1) spherical 0.0000 3.0405 1.52 67.0 refraction S4 aspherical -116.2882 0.2055 refraction S5 Second lens (E2) aspherical 42.4663 10.2223 1.54 65.8 refraction S6 aspherical -181.8876 0.1000 refraction S7 Third lens (E3) aspherical 186.3709 1.1836 1.76 27.6 refraction S8 aspherical 75.4616 14.9841 refraction S9 monitor spherical endless refraction

[0096] Table 5

[0097] Face number A4 A6 A8 A10 A12 S4 2.8939E+01 1.0708E-01 2.7492E-02 -1.2377E-02 -2.5877E-03 S5 2.4928E+01 -5.9127E-01 -4.3209E-01 1.8430E-02 5.7858E-03 S6 2.5517E+01 -8.4560E-03 -3.9296E-02 -4.2223E-02 7.2103E-02 S7 1.9455E+01 1.1687E-01 -7.6035E-02 4.0654E-02 2.7049E-03 S8 2.1568E+01 -1.0381E+00 -5.7249E-01 1.9298E-01 -1.7068E-02

[0098] Table 6

[0099] The relevant parameter values ​​in Example 3 are shown in Table 7. The meaning of each parameter is as described above and will not be repeated here. The unit of each parameter in Table 7 is millimeters (mm).

[0100] Figure 16 The on-axis chromatic aberration curve of the visual optical system of Embodiment 3 is shown, which represents the deviation of the convergence focal point of light of different wavelengths after passing through the lens. Figure 17 The 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 18 The distortion curves of the visual optical system of Embodiment 3 are shown, representing the distortion magnitude values ​​corresponding to different image heights. According to... Figures 16 to 18 It can be seen that the visual optical system given in Example 3 can achieve good imaging quality.

[0101]

[0102]

[0103] Table 7

[0104] Furthermore, in Embodiments 1 to 3, the effective focal length f of the visual optical system, the combined focal length FG12 of the first lens group (first lens, reflective polarizing element, quarter-wave plate) and the second lens, the combined focal length f23 of the second lens and the third lens, the axial distance SAG31 from the intersection of the first side surface of the third lens and the optical axis to the vertex of the effective radius of the first side surface of the third lens, and the axial distance SAG32 from the intersection of the second side surface of the third lens and the optical axis to the vertex of the effective radius of the second side surface of the third lens are shown in Table 8.

[0105] Parameters / Examples 1 2 3 f(mm) 27.89 25.89 24.80 FG12(mm) 32.43 27.10 25.37 f23(mm) 82.30 80.92 76.32 SAG31 (mm) 10.31 8.76 1.15 SAG32 (mm) 3.82 4.40 3.52

[0106] Table 8

[0107] Examples 1 to 3 respectively satisfy the conditions shown in Table 9.

[0108] Conditional / Example 1-1 1-2 1-3 2-1 2-2 2-3 3-1 3-2 3-3 R4 / d2s+D2m / R5 -0.59 -0.64 -0.68 6.87 6.86 6.64 -3.50 -3.54 -3.55 f23 / (N3×EP12) 23.21 23.50 14.09 6.70 6.55 25.50 3.99 4.10 4.10 L / (CT2+T23) 3.93 3.76 3.54 4.72 4.53 4.33 2.25 2.18 2.09 d0s / EP01+d0m / f 17.12 18.13 23.76 13.11 15.56 17.81 19.43 17.69 20.81 (R5+R6) / |d0m-d0s| 8.35 9.94 12.25 8.27 8.98 9.45 15.23 15.98 19.55 (V2+V3)×(CT2+EP12) / FG12 33.95 33.82 40.64 67.45 68.44 36.43 77.69 76.59 76.59 TD / EP12 8.51 8.62 5.17 1.87 1.83 7.12 1.36 1.39 1.39 (D2s-d2s) / (SAG31-SAG32) 2.18 1.75 1.55 1.95 1.97 0.86 -3.51 -4.41 -3.91 (D2s-d2m) / (CT2-CT1) 3.25 2.61 2.31 5.27 5.34 2.34 1.24 1.46 1.29 f / (D1m-d1m) 3.07 3.76 3.05 3.04 2.94 6.76 1.63 1.75 2.03 L / |D0m-D0s| 7.28 5.92 12.65 7.99 7.39 9.88 4.57 5.42 7.95

[0109] Table 9

[0110] This application also provides an imaging device equipped with an electronic photosensitive element for imaging. The electronic photosensitive element can be a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) device. The imaging device can be a standalone imaging device such as a digital camera, or an imaging module integrated into a mobile electronic device such as a mobile phone. This imaging device is equipped with the visual optical system described above.

[0111] 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 protection 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 concept of this application. 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 by, comprising a lens barrel and a first lens group, a second lens and a third lens accommodated in the lens barrel in order from a first side to a second side along an optical axis, wherein the first lens group comprises a first lens, a reflective polarizing element and a quarter wave plate; the reflective polarizing element and the quarter wave plate are attached to the first side or the second side of the first lens; a first spacer element is provided between the first lens and the second lens, a first side of the first spacer element being at least partially in contact with a second side of the first lens; a second spacer element is provided between the second lens and the third lens, a first side of the second spacer element being at least partially in contact with a second side of the second lens; the number of lenses having optical power in the visual optical system is three; the visual optical system satisfies: 3.99 ≤ f23 / (N3 x EP12) ≤ 25.50, wherein f23 is a combined focal length of the second lens and the third lens, N3 is a refractive index of the third lens, and EP12 is a distance of the first spacer element to the second spacer element along a direction parallel to the optical axis.

2. The visual optical system according to claim 1, characterized in that the first lens or the second lens has a partial reflection layer.

3. The visual optical system of claim 1, wherein a first side of the reflective polarizing element is attached to a second side of the first lens, and a first side of the quarter wave plate is attached to a second side of the reflective polarizing element.

4. The visual optical system of claim 1, wherein a second side of the reflective polarizing element is attached to a first side of the quarter wave plate, and a second side of the quarter wave plate is attached to a first side of the first lens.

5. The visual optical system of claim 1, wherein a radius of curvature R4 of a second side of the second lens, an inner diameter d2s of a first side of the second spacer element, an outer diameter D2m of a second side of the second spacer element, and a radius of curvature R5 of a first side of the third lens satisfy: -3.55 ≤ R4 / d2s + D2m / R5 ≤ 6.

87.

6. The visual optical system of claim 1, wherein a maximum height L of the lens barrel along the optical axis direction, a central thickness CT2 of the second lens on the optical axis, and an air separation T23 of the second lens and the third lens on the optical axis satisfy: 2.09 ≤ L / (CT2 + T23) ≤ 4.

72.

7. The visual optical system according to any one of claims 1 to 6, characterized in that an inner diameter d0s of a first side end surface of the lens barrel, a distance EP01 of the first side end surface of the lens barrel to the first side of the first spacer element along a direction parallel to the optical axis, an inner diameter d0m of a second side end surface of the lens barrel, and an effective focal length f of the visual optical system satisfy: 13.11 ≤ d0s / EP01 + d0m / f ≤ 23.

76.

8. The visual optical system according to any one of claims 1 to 6, characterized in that a radius of curvature R5 of a first side of the third lens, a radius of curvature R6 of a second side of the third lens, the inner diameter d0m of the second side end surface of the lens barrel, and the inner diameter d0s of the first side end surface of the lens barrel satisfy: 8.27 ≤ (R5 + R6) / |d0m - d0s| ≤ 19.

55.

9. The visual optical system according to any one of claims 1 to 6, characterized in that An Abbe number V2 of the second lens, an Abbe number V3 of the third lens, a central thickness CT2 of the second lens on the optical axis, a distance EP12 of the first spacer element to the second spacer element along a direction parallel to the optical axis, and a combined focal length FG12 of the first lens group and the second lens satisfy: 33.82 ≤ (V2 + V3) x (CT2 + EP12) / FG12 ≤ 77.

69.

10. The visual optical system according to any one of claims 1 to 6, characterized in that A distance TD of the first side surface of the first lens to the second side surface of the third lens on the optical axis and the distance EP12 of the first spacer element to the second spacer element along the direction parallel to the optical axis satisfy: 1.36 ≤ TD / EP12 ≤ 8.

62.

11. The visual optical system according to any one of claims 1 to 6, characterized in that An outer diameter D2s of the first side surface of the second spacer element, an inner diameter d2s of the first side surface of the second spacer element, an on-axis distance SAG31 of an intersection of the first side surface of the third lens and the optical axis to an effective radius vertex of the first side surface of the third lens, and an on-axis distance SAG32 of an intersection of the second side surface of the third lens and the optical axis to an effective radius vertex of the second side surface of the third lens satisfy: -4.41 ≤ (D2s - d2s) / (SAG31 - SAG32) ≤ 2.

18.

12. The visual optical system according to any one of claims 1 to 6, characterized in that The outer diameter D2s of the first side surface of the second spacer element, an inner diameter d2m of the second side surface of the second spacer element, a central thickness CT2 of the second lens on the optical axis, and a central thickness CT1 of the first lens on the optical axis satisfy: 1.24 ≤ (D2s - d2m) / (CT2 - CT1) ≤ 5.

34.

13. The visual optical system according to any one of claims 1 to 6, characterized in that An effective focal length f of the visual optical system, an outer diameter D1m of the second side surface of the first spacer element, and an inner diameter d1m of the second side surface of the first spacer element satisfy: 1.63 ≤ f / (D1m - d1m) ≤ 6.

76.

14. The visual optical system according to any one of claims 1 to 7, characterized in that A maximum height L of the lens barrel along the optical axis direction, an outer diameter D0m of the second side end surface of the lens barrel, and an outer diameter D0s of the first side end surface of the lens barrel satisfy: 4.57 ≤ L / |D0m - D0s| ≤ 12.

65.

15. A VR device comprising the visual optical system of any one of claims 1 to 14, wherein, The first side is an eye side, and the second side is a display side.

Images