Visual system

Abstract

The application provides a visual system. The visual system comprises a first lens barrel, a second lens barrel, a first element group and a second element group. The first element group comprises a first lens, a polarizer, a reflective polarizing element and a quarter-wave plate in sequence from a first side to a second side along an optical axis of the visual system. The second element group comprises a second lens, a reflective element and a display in sequence from the first side to the second side along the optical axis. The second element group is movably arranged along the optical axis. The following conditions are met: 2.07<=R1 / damin<=2.70; and 3.99<=(La+Lb) / DeltaL<=5.99. The application solves the problem that the prior art visual system with two pieces has a limited size design of the first lens due to control of the focal power and the surface type of the first lens, poor assembly and support stability of the first lens, and a large variation of the surface type of the field curvature.

Description

Technical Field

[0001] This invention relates to the field of optical imaging equipment technology, and more specifically, to a visual system. Background Technology

[0002] In existing optical systems, visual systems consisting of two lenses are widely used in various scenarios, including but not limited to VR devices and AR devices.

[0003] This type of visual system typically matches actual needs by setting up refractive and reflective elements and controlling the optical power and surface shape of the front lens, i.e., the first lens. However, in this case, the size design of the first lens is easily limited, especially the design of the center thickness and edge thickness of the first lens. Unreasonable size can easily lead to poor assembly and support stability of the first lens, making the first lens susceptible to deformation under pressure during assembly, which in turn leads to a deterioration of the surface curvature of the first lens and affects the image quality.

[0004] In other words, the existing two-piece visual system has the problem of controlling the optical power and surface shape of the first lens, which limits the size design of the first lens, resulting in poor assembly and support stability of the first lens, and consequently, large changes in surface curvature. Summary of the Invention

[0005] The main objective of this invention is to provide a visual system that addresses the problem in existing two-piece visual systems where controlling the optical power and surface shape of the first lens restricts its size design, leading to poor assembly and support stability of the first lens and consequently large variations in surface curvature.

[0006] To achieve the above objectives, according to one aspect of the present invention, a visual system is provided, comprising a first lens barrel, a second lens barrel, a first element group, and a second element group. At least a portion of the first element group is housed in the first lens barrel, and at least a portion of the second element group is housed in the second lens barrel. The first element group, along the optical axis of the visual system from a first side to a second side, sequentially includes a first lens, a polarizer, a reflective polarizing element, and a quarter-wave plate. The polarizer, the reflective polarizing element, and the quarter-wave plate are sequentially disposed on the second side surface of the first lens in a direction away from the first lens. The first lens has positive optical power, the first side surface of the first lens is convex, and the second side surface of the first lens is planar. The second element group, along the optical axis from a first side to a second side, sequentially includes a second lens, a reflective element, and a display. The reflective element is disposed... On the second side surface of the second lens; the second lens has positive optical power, the first side surface of the second lens is convex, and the second side surface of the second lens is convex; the second element group is movably arranged along the optical axis; the number of lenses in the visual system is two; the radius of curvature R1 of the first side surface of the first lens and the minimum inner diameter damin of the first lens barrel satisfy: 2.07≤R1 / damin≤2.70; the distance La between the first side surface of the first lens barrel and the second side surface of the first lens barrel on the optical axis, the distance Lb between the first side surface of the second lens barrel and the second side surface of the second lens barrel on the optical axis, and the distance ΔL that the second element group moves along the optical axis when the visual system moves from +2D state to -5D state satisfy: 3.99≤(La+Lb) / ΔL≤5.99.

[0007] According to another aspect of the present invention, a visual system is also provided, comprising a first lens barrel, a second lens barrel, a first element group, and a second element group. At least a portion of the first element group is housed in the first lens barrel, and at least a portion of the second element group is housed in the second lens barrel. The first element group, along the optical axis of the visual system, sequentially includes a first lens, a polarizer, a reflective polarizing element, and a quarter-wave plate from a first side to a second side. The polarizer, the reflective polarizing element, and the quarter-wave plate are sequentially disposed on the second side surface of the first lens in a direction away from the first lens. The first lens has positive optical power, the first side surface of the first lens is convex, and the second side surface of the first lens is planar. The second element group, along the optical axis, sequentially includes a second lens, a reflective element, and a display from a first side to a second side. The reflective element is disposed on the second lens. On the second side surface; the second lens has positive optical power, the first side surface of the second lens is convex, and the second side surface of the second lens is convex; the second element group is movably arranged along the optical axis; the number of lenses in the visual system is two; the radius of curvature R4 of the second side surface of the second lens and the minimum inner diameter dbmin of the second lens barrel satisfy: -2.91≤R4 / dbmin≤-2.59; the distance La between the first side surface of the first lens barrel and the second side surface of the first lens barrel on the optical axis, the distance Lb between the first side surface of the second lens barrel and the second side surface of the second lens barrel on the optical axis, and the distance ΔL that the second element group moves along the optical axis when the visual system moves from +2D state to -5D state satisfy: 3.99≤(La+Lb) / ΔL≤5.99.

[0008] Furthermore, the outer diameter Das of the first side surface of the first lens barrel and the center thickness CT1 of the first lens on the optical axis satisfy the following condition: 8.51≤Das / CT1≤10.20.

[0009] Furthermore, the central thickness CT2 of the second lens on the optical axis and the distance Lb between the first side surface and the second side surface of the second lens barrel on the optical axis satisfy the following condition: 0.94≤CT2 / Lb≤1.47.

[0010] Furthermore, the radius of curvature R4 of the second side surface of the second lens satisfies the following relationship with the minimum inner diameter dbmin of the second lens barrel: -2.91≤R4 / dbmin≤-2.59.

[0011] Furthermore, the inner diameter dbs of the first side surface of the second lens barrel, the inner diameter dbm of the second side surface of the second lens barrel, and the change in the effective focal length Δf of the visual system when the visual system moves from the +2D state to the -5D state satisfy the following: 2.18≤(dbs-dbm) / Δf≤5.43.

[0012] Furthermore, the distance La between the first side surface and the second side surface of the first lens barrel on the optical axis, the combined focal length fz of the first lens, the polarizer, the reflective polarizing element and the quarter-wave plate, and the effective focal length f2 of the second lens satisfy the following: 3.31mm≤La×(fz / f2)≤6.50mm.

[0013] Furthermore, the radius of curvature R3 of the first side surface of the second lens and the outer diameter Dbs of the first side surface of the second lens barrel satisfy the following condition: 4.82≤R3 / Dbs≤7.68.

[0014] Furthermore, the inner diameter dam of the second side surface of the first lens barrel, the inner diameter das of the first side surface of the first lens barrel, and the distance ΔL that the second element group moves along the optical axis when the visual system moves from the +2D state to the -5D state satisfy the following: 2.43≤(dam-das) / ΔL≤5.53.

[0015] Furthermore, the effective focal length f1 of the first lens and the outer diameter Dam of the second side surface of the first lens barrel satisfy the following condition: 2.76≤f1 / Dam≤3.29.

[0016] Furthermore, the minimum inner diameter dbmin of the second lens tube, the minimum inner diameter damin of the first lens tube, and the distance ΔL that the second element group moves along the optical axis when the visual system moves from the +2D state to the -5D state satisfy the following: 1.49≤(dbmin-damin) / ΔL≤4.19.

[0017] Furthermore, the outer diameter Dbm of the second side surface of the second lens barrel, the inner diameter dbm of the second side surface of the second lens barrel, and the distance BFL from the second side surface of the second lens to the display on the optical axis satisfy the following condition: 3.61≤(Dbm-dbm) / BFL≤7.20.

[0018] Furthermore, the minimum inner diameter damin of the first lens tube and the distance La between the first side surface and the second side surface of the first lens tube on the optical axis satisfy the following condition: 3.97≤damin / La≤9.26.

[0019] Furthermore, the minimum inner diameter dbmin of the second lens tube and the distance Lb between the first side surface and the second side surface of the second lens tube on the optical axis satisfy the following condition: 5.35≤dbmin / Lb≤8.89.

[0020] Furthermore, the effective focal length f2 of the second lens, the refractive index N2 of the second lens, and the inner diameter dbs of the first side surface of the second lens barrel satisfy the following condition: 1.94≤(f2 / N2) / dbs≤2.22.

[0021] By applying the technical solution of this invention, and designing the first lens to have positive optical power and a convex-flat surface, and setting a polarizer, a reflective polarizing element, and a quarter-wave plate on the second side surface of the first lens, while simultaneously designing the second lens to have positive optical power and a convex-convex surface, and setting a reflective element on the second side surface of the second lens, it is evident that the size design of the first lens is limited, especially the center thickness and edge thickness of the first lens. An unreasonable size of the first lens can easily lead to a decrease in the assembly and support stability of the first lens, making the first lens prone to deformation under pressure during assembly, thereby resulting in a deterioration in the surface curvature of the first lens and affecting the imaging quality. By constraining 2.07≤R1 / damin≤2.70 and 3.99≤(La+Lb) / ΔL≤5.99, this application helps to ensure the rationality of the surface shape and size of the first lens. This results in better assembly and support stability of the first lens in the first lens barrel in both +2D and -5D states of the visual system. This improves the assembly stability of the first lens, reduces the risk of assembly deformation, reduces the amount of surface curvature change of the first lens, and ensures field curvature stability, thereby guaranteeing the imaging quality of the visual system. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram showing the dimensioning of a visual system according to an alternative embodiment of the present invention is illustrated. Figure 2 A schematic diagram of the visual system of Embodiment 1-1 of the present invention in the +2D state is shown; Figure 3 A schematic diagram of the visual system of Embodiment 1-1 of the present invention in the -5D state is shown; Figure 4 The diagram shows the structure of the visual system of Embodiments 1-2 of the present invention in the +2D state; Figure 5 The diagram shows the structural schematics of the visual systems of embodiments 1-2 of the present invention in the -5D state; Figure 6 The diagram shows the structural schematics of the visual systems of embodiments 1-3 of the present invention in the +2D state; Figure 7 The diagram shows the structural schematics of the visual systems of embodiments 1-3 of the present invention in the -5D state; Figure 8 The diagram shows the optical modulation function curve of the visual system of Embodiment 1 of the present invention in +2D state; Figure 9The diagram shows the optical modulation function curve of the visual system of Embodiment 1 of the present invention in -5D state; Figure 10 A schematic diagram of the visual system of Embodiment 2-1 of the present invention in the +2D state is shown; Figure 11 A schematic diagram of the visual system of Embodiment 2-1 of the present invention in -5D state is shown; Figure 12 A schematic diagram of the visual system of Embodiment 2-2 of the present invention in the +2D state is shown; Figure 13 A schematic diagram of the visual system of Embodiment 2-2 of the present invention in the -5D state is shown; Figure 14 The diagram shows the structural schematics of the visual system of embodiments 2-3 of the present invention in the +2D state; Figure 15 The diagram shows the structural schematics of the visual system of embodiments 2-3 of the present invention in the -5D state; Figure 16 The diagram shows the optical modulation function curve of the visual system of Embodiment 2 of the present invention in +2D state; Figure 17 The diagram shows the optical modulation function curve of the visual system of Embodiment 2 of the present invention in -5D state; Figure 18 A schematic diagram of the visual system of Embodiment 3-1 of the present invention in the +2D state is shown; Figure 19 A schematic diagram of the visual system of Embodiment 3-1 of the present invention in the -5D state is shown; Figure 20 A schematic diagram of the visual system of Embodiment 3-2 of the present invention in the +2D state is shown; Figure 21 A schematic diagram of the visual system of Embodiment 3-2 of the present invention in the -5D state is shown; Figure 22 A schematic diagram of the visual system of Embodiment 3-3 of the present invention in the +2D state is shown; Figure 23 A schematic diagram of the visual system of Embodiment 3-3 of the present invention in the -5D state is shown; Figure 24 The diagram shows the optical modulation function curve of the visual system of Embodiment 3 of the present invention in +2D state; Figure 25 The diagram shows the optical modulation function curve of the visual system of Embodiment 3 of the present invention in -5D state.

[0023] The above figures include the following reference numerals: Pa, first lens barrel; Pb, second lens barrel; E1, first lens; E2, second lens; LP, polarizer; RP, reflective polarizing element; QWP, quarter-wave plate; BS, reflective element; IMG, image plane. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0026] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0027] 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 drawn strictly to scale.

[0028] In this paper, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of that 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 that concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The determination of the surface shape in the paraxial region can be based on the judgment method commonly used by those knowledgeable in the field, using the R value (R refers to the radius of curvature of the paraxial region, usually the R value in the lens database of optical software) to determine convexity or concavity. For the first side surface, when the R value is positive, it is determined to be convex, and when the R value is negative, it is determined to be concave; for the second side surface, when the R value is positive, it is determined to be concave, and when the R value is negative, it is determined to be convex. When the R value is infinite, it is determined to be a plane.

[0029] In this application, the first side refers to the side of the viewing system facing the human eye (not shown in the figure), and the second side refers to the side of the viewing system facing the display, which has an image surface (IMG). In the following text, the first side surface of a lens refers to the surface of the lens facing the human eye (not shown in the figure), and the second side surface of a lens refers to the surface of the lens facing the display. In the structural schematic diagram shown in this application, the left side is the first side, and the right side is the second side.

[0030] To address the problem in existing two-piece visual systems where controlling the optical power and surface shape of the first lens restricts its size design, leading to poor assembly and support stability and consequently large variations in surface curvature, this invention provides a visual system.

[0031] like Figures 1 to 25 As shown, in an optional embodiment of this application, the visual system includes a first lens barrel, a second lens barrel, a first element group, and a second element group. At least a portion of the first element group is housed in the first lens barrel, and at least a portion of the second element group is housed in the second lens barrel. The first element group, along the optical axis of the visual system, sequentially includes a first lens, a polarizer, a reflective polarizing element, and a quarter-wave plate from the first side to the second side. The polarizer, reflective polarizing element, and quarter-wave plate are sequentially disposed on the second side surface of the first lens in a direction away from the first lens. The first lens has positive optical power, the first side surface of the first lens is convex, and the second side surface of the first lens is planar. The second element group, along the optical axis, sequentially includes a second lens, a reflective element, and a display from the first side to the second side. The reflective element is disposed on the second lens. On the second side surface of the mirror; the second lens has positive optical power, the first side surface of the second lens is convex, and the second side surface of the second lens is convex; the second element group is movably arranged along the optical axis; the number of lenses in the visual system is two; the radius of curvature R1 of the first side surface of the first lens and the minimum inner diameter damin of the first lens barrel satisfy: 2.07≤R1 / damin≤2.70; the distance La between the first side surface of the first lens barrel and the second side surface of the first lens barrel on the optical axis, the distance Lb between the first side surface of the second lens barrel and the second side surface of the second lens barrel on the optical axis, and the distance ΔL that the second element group moves along the optical axis when the visual system moves from +2D state to -5D state satisfy: 3.99≤(La+Lb) / ΔL≤5.99.

[0032] By designing the first lens to have positive optical power and a convex-flat surface, and setting a polarizer, a reflective polarizing element, and a quarter-wave plate on the second side surface of the first lens, while designing the second lens to have positive optical power and a convex-convex surface, and setting a reflective element on the second side surface of the second lens, it is evident that the size design of the first lens is limited, especially the center thickness and edge thickness of the first lens. An unreasonable size of the first lens can easily lead to poor assembly and support stability of the first lens, making the first lens prone to deformation under pressure during assembly, which in turn leads to a deterioration of the surface curvature of the first lens and affects the image quality. By constraining 2.07≤R1 / damin≤2.70 and 3.99≤(La+Lb) / ΔL≤5.99, this application helps to ensure the rationality of the surface shape and size of the first lens. This results in better assembly and support stability of the first lens in the first lens barrel in both +2D and -5D states of the visual system. This improves the assembly stability of the first lens, reduces the risk of assembly deformation, reduces the amount of surface curvature change of the first lens, and ensures field curvature stability, thereby guaranteeing the imaging quality of the visual system.

[0033] It should be noted that the refractive accommodation capability of the visual system in this application covers a continuous range from hyperopia correction to myopia correction. Specifically, when the visual system is in +2D mode, it can accommodate users with hyperopia up to 200 degrees; while when the visual system switches to -5D mode, it can accommodate users with myopia up to 500 degrees. It is worth noting that the visual system in this application is not limited to these two extreme states; it also has several intermediate states where the refractive power can be flexibly adjusted between +2D and -5D to meet the needs of a wide range of users from mild hyperopia to moderate myopia. This broad range of refractive power accommodation is achieved by precisely adjusting the position of the second element assembly on the optical axis, ensuring smooth and efficient adjustment of the visual system between +2D and -5D modes.

[0034] Furthermore, referring to Table 1 below, Table 1 is a comprehensive sensitivity table of surface curvature of the first lens during the assembly process. The table below shows the changes in field curvature of the first side surface and the second side surface of the first lens under different fields of view from 0.1F to 1.0F for Scheme 1, Comparative Example 1, and Comparative Example 2 of the present invention.

[0035] As shown in Table 1, when the visual system of Scheme 1 of the present invention satisfies R1 / damin=2.45 and (La+Lb) / ΔL=4.59, the size of the first lens is more reasonable. During assembly, the shape deformation of the first lens is smaller, and the field curvature changes of the first and second side surfaces of the first lens are smaller, resulting in better performance. When the visual system of Comparative Example 1 satisfies R1 / damin=3.1 and (La+Lb) / ΔL=7.8, during assembly, the shape deformation of the first lens is larger, and the field curvature changes of the first and second side surfaces of the first lens are larger, resulting in poorer performance. When the visual system of Comparative Example 2 satisfies R1 / damin=1.7 and (La+Lb) / ΔL=2.4, during assembly, the shape deformation of the first lens is larger, and the field curvature changes of the first and second side surfaces of the first lens are larger, resulting in poorer performance. Therefore, when the visual system satisfies 2.07≤R1 / damin≤2.70 and 3.99≤(La+Lb) / ΔL≤5.99, the deformation of the first lens under pressure during assembly is small, and the change in surface curvature on both sides of the first lens is also small. Thus, by constraining 2.07≤R1 / damin≤2.70 and 3.99≤(La+Lb) / ΔL≤5.99, this application ensures the rationality of the surface shape and dimensions of the first lens. This results in better assembly and support stability of the first lens in the first lens barrel in both +2D and -5D states, improving the assembly stability of the first lens, reducing the risk of assembly deformation, decreasing the change in surface curvature, ensuring field curvature stability, and ultimately guaranteeing the imaging quality of the visual system.

[0036] Table 1

[0037] It should be noted that since the second element group is housed in the second lens barrel, when the second element group moves along the optical axis toward the direction of approaching or moving away from the first element group, the second lens barrel moves together with the second element group.

[0038] In this embodiment, the outer diameter Das of the first side surface of the first lens barrel and the center thickness CT1 of the first lens on the optical axis satisfy the following condition: 8.51≤Das / CT1≤10.20. By reasonably controlling the range of this condition, it is beneficial to improve the manufacturability of the first lens while ensuring the assembly stability of the visual system, thereby ensuring the light deflection effect of the first lens.

[0039] In this embodiment, the center thickness CT2 of the second lens on the optical axis and the distance Lb between the first side surface and the second side surface of the second lens barrel on the optical axis satisfy the condition: 0.94≤CT2 / Lb≤1.47. By reasonably controlling this condition range, it is beneficial to improve the manufacturability and assembly stability of the second lens, and ensure the refractive effect of the second lens on light.

[0040] In this embodiment, the radius of curvature R4 of the second side surface of the second lens and the minimum inner diameter dbmin of the second lens barrel satisfy the following relationship: -2.91 ≤ R4 / dbmin ≤ -2.59. By controlling the ratio between the radius of curvature of the second side surface of the second lens and the minimum inner diameter of the second lens barrel, the shape of the second lens is constrained, ensuring the surface stability of the second lens, which helps to reduce the sensitivity of the second lens and thus improve the assembly yield. On the other hand, it can ensure that the inner diameter of the second lens barrel and the refractive properties of the second lens are matched, control the inner diameter of the second lens barrel to prevent blocking of effective light rays, and block ineffective light rays, which helps to reduce the risk of stray light and ensure light efficiency.

[0041] In this embodiment, the inner diameter dbs of the first side surface of the second lens barrel, the inner diameter dbm of the second side surface of the second lens barrel, and the change in effective focal length Δf of the visual system when the visual system moves from a +2D state to a -5D state satisfy the following condition: 2.18 ≤ (dbs - dbm) / Δf ≤ 5.43. By reasonably controlling the range of this condition, it is possible to prevent it from exceeding the upper limit, which would increase the size of the module that cooperates with the visual system and thus affect the overall size of the device, and to prevent it from falling below the lower limit, which would result in insufficient strength of the second lens barrel for the performance of the module that cooperates with it.

[0042] In this embodiment, the distance La between the first and second side surfaces of the first lens barrel on the optical axis, the combined focal length fz of the first lens, polarizer, reflective polarizing element, and quarter-wave plate, and the effective focal length f2 of the second lens satisfy the following condition: 3.31mm ≤ La × (fz / f2) ≤ 6.50mm. By reasonably controlling the range of this condition, the first element group can generate positive spherical aberration, which is balanced with the negative spherical aberration generated by other lenses in the visual system, thereby ensuring good on-axis imaging quality of the visual system. Secondly, controlling the distance between the first and second side surfaces of the first lens barrel on the optical axis, while ensuring its function of limiting the first lens, is beneficial to improving the manufacturability of the first lens barrel.

[0043] In this embodiment, the radius of curvature R3 of the first side surface of the second lens and the outer diameter Dbs of the first side surface of the second lens barrel satisfy the following condition: 4.82 ≤ R3 / Dbs ≤ 7.68. By reasonably controlling the range of this condition, on the one hand, the shape of the second lens is constrained, which helps to reduce the sensitivity of the second lens and thus improve the assembly yield; on the other hand, it can ensure the feasibility of forming the second lens barrel.

[0044] In this embodiment, the inner diameter dam of the second side surface of the first lens barrel, the inner diameter das of the first side surface of the first lens barrel, and the distance ΔL that the second element group moves along the optical axis when the visual system moves from a +2D state to a -5D state satisfy the following condition: 2.43 ≤ (dam-das) / ΔL ≤ 5.53. By reasonably controlling the range of this condition, it is possible to prevent the value from being less than the lower limit, which would cause an unreasonable maximum thickness of the first lens barrel due to its size, thus affecting the user experience; and it is also possible to prevent the value from exceeding the upper limit, which would cause interference problems with the first lens barrel under high-power focusing conditions, thus avoiding situations where the function cannot be achieved.

[0045] In this embodiment, the effective focal length f1 of the first lens and the outer diameter Dam of the second side surface of the first lens barrel satisfy the following relationship: 2.76 ≤ f1 / Dam ≤ 3.29. By controlling the above relationship, the shape of the first lens is restricted, improving the manufacturability of the first lens; at the same time, the outer diameter of the first lens barrel is restricted, which is beneficial to the reduction of the overall size and meets the miniaturization requirements.

[0046] In this embodiment, the minimum inner diameter dbmin of the second lens barrel, the minimum inner diameter damin of the first lens barrel, and the distance ΔL that the second element group moves along the optical axis when the visual system moves from a +2D state to a -5D state satisfy the following relationship: 1.49 ≤ (dbmin - damin) / ΔL ≤ 4.19. By controlling the above relationship, the minimum inner diameters of the first lens and the second lens barrel, and the distance that the second element group moves along the optical axis under different focusing states are controlled within a certain range. This is beneficial for controlling the stability of the light transmission of the visual system under different focusing states, preventing the problem of increased stray light due to a large inner diameter and the problem of excessively low brightness entering the eye due to a small inner diameter.

[0047] In this embodiment, the outer diameter Dbm of the second side surface of the second lens barrel, the inner diameter dbm of the second side surface of the second lens barrel, and the distance BFL from the second side surface of the second lens to the display on the optical axis satisfy the following condition: 3.61 ≤ (Dbm - dbm) / BFL ≤ 7.20. By limiting the ratio between the difference between the outer and inner diameters of the second side surface of the second lens barrel and the distance from the second side surface of the second lens to the display on the optical axis, the amount of light emitted from the display passing through the second lens is effectively controlled, preventing excessively low brightness at the eye; it also prevents problems such as high stray light risk caused by an excessively large aperture.

[0048] In this embodiment, the minimum inner diameter damin of the first lens barrel and the distance La between the first side surface and the second side surface of the first lens barrel on the optical axis satisfy the following relationship: 3.97≤damin / La≤9.26. By controlling the above relationship, on the one hand, the processing feasibility of the first side end of the first lens barrel can be improved, and the dispensing assembly of the first lens and the first lens barrel can be facilitated. On the other hand, the overall shape and length of the first lens barrel are limited, which is beneficial to the miniaturization of the visual system.

[0049] In this embodiment, the minimum inner diameter dbmin of the second lens barrel and the distance Lb between the first side surface and the second side surface of the second lens barrel on the optical axis satisfy the following relationship: 5.35≤dbmin / Lb≤8.89. By controlling the above relationship, it is beneficial to ensure the feasibility of manufacturing the second lens barrel; in addition, it indirectly restricts the overall shape and length of the second lens barrel, preventing interference between the second lens barrel and other components during focusing.

[0050] In this embodiment, the effective focal length f2 of the second lens, the refractive index N2 of the second lens, and the inner diameter dbs of the first side surface of the second lens barrel satisfy the following relationship: 1.94 ≤ (f2 / N2) / dbs ≤ 2.22. By controlling the relationship between the effective focal length and refractive index of the second lens, aberrations can be effectively corrected and image quality improved. At the same time, limiting the inner diameter of the first side surface of the second lens barrel can better address the issue of stray light, enabling the second lens barrel to effectively intercept stray light.

[0051] In another optional embodiment of this application, a visual system is also provided, including a first lens barrel, a second lens barrel, a first element group, and a second element group. At least a portion of the first element group is housed in the first lens barrel, and at least a portion of the second element group is housed in the second lens barrel. The first element group, along the optical axis of the visual system, sequentially includes a first lens, a polarizer, a reflective polarizing element, and a quarter-wave plate from the first side to the second side. The polarizer, reflective polarizing element, and quarter-wave plate are sequentially disposed on the second side surface of the first lens in a direction away from the first lens. The first lens has positive optical power, the first side surface of the first lens is convex, and the second side surface of the first lens is planar. The second element group, along the optical axis, sequentially includes a second lens, a reflective element, and a display from the first side to the second side. The reflective element is disposed on... On the second side surface of the second lens; the second lens has positive optical power, the first side surface of the second lens is convex, and the second side surface of the second lens is convex; the second element group is movably arranged along the optical axis; the number of lenses in the visual system is two; the radius of curvature R4 of the second side surface of the second lens and the minimum inner diameter dbmin of the second lens barrel satisfy: -2.91≤R4 / dbmin≤-2.59; the distance La between the first side surface of the first lens barrel and the second side surface of the first lens barrel on the optical axis, the distance Lb between the first side surface of the second lens barrel and the second side surface of the second lens barrel on the optical axis, and the distance ΔL that the second element group moves along the optical axis when the visual system moves from +2D state to -5D state satisfy: 3.99≤(La+Lb) / ΔL≤5.99.

[0052] By designing the first lens to have positive optical power and a convex-flat surface, and setting a polarizer, a reflective polarizing element, and a quarter-wave plate on the second side surface of the first lens, and simultaneously designing the second lens to have positive optical power and a convex-convex surface, and setting a reflective element on the second side surface of the second lens, it is evident that the size design of the first and second lenses is limited. Unreasonable sizes of the first and second lenses can easily lead to poor assembly and support stability of the first and second lenses, making them prone to deformation under pressure during assembly, which in turn leads to a deterioration in the surface curvature of the first and second lenses, affecting the image quality. This application, by constraining -2.91≤R4 / dbmin≤-2.59 and 3.99≤(La+Lb) / ΔL≤5.99, helps to ensure the rationality of the surface shape and size of the first and second lenses. This results in better assembly and support stability of the first lens in the first lens barrel and better assembly stability in the second lens barrel in both +2D and -5D states of the visual system. This improves the assembly stability of the first and second lenses, reduces the risk of assembly deformation of the first and second lenses, reduces the amount of surface curvature change of the first and second lenses, ensures field curvature stability, and thus ensures the imaging quality of the visual system.

[0053] Of course, this embodiment may also include other parametric expressions as described in the above embodiments, which will not be elaborated here.

[0054] The visual system in this application may employ multiple lenses, such as the two lenses described above. In this application, at least one of the mirror surfaces of each 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 superior curvature radius characteristics, offering advantages in improving distortion aberrations and astigmatism. By using aspherical lenses, aberrations occurring during imaging can be eliminated as much as possible, thereby improving image quality.

[0055] However, those skilled in the art will understand that the number of lenses constituting the visual 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 two lenses are described as an example in the embodiments, the visual system is not limited to including two lenses. If necessary, the visual system may also include other numbers of lenses.

[0056] Figure 1 A schematic diagram of the dimensioning of a visual system according to an optional embodiment of the present invention is shown. Figure 1 The parameters Dbs, dbs, Das, das, damin, dbmin, dbm, dam, Dbm, Dam, La, and Lb are clearly and intuitively illustrated to provide a clear understanding of their meaning. To facilitate the description of the visual system and the specific lens profiles, these parameters will not be shown in the accompanying drawings when describing specific embodiments.

[0057] The following description, with reference to the accompanying drawings, further illustrates examples of specific surface shapes and parameters applicable to the visual system described above.

[0058] It should be noted that in the following Embodiment 1, there are three examples: Embodiment 1-1, Embodiment 1-2, and Embodiment 1-3; in Embodiment 2, there are three examples: Embodiment 2-1, Embodiment 2-2, and Embodiment 2-3; and in Embodiment 3, there are three examples: Embodiment 3-1, Embodiment 3-2, and Embodiment 3-3. The optical system parameters in the visual system under the three examples in the same embodiment are the same. Specifically, the radius of curvature, center thickness, and other parameters of the first and second lenses of the visual system, as well as the spacing distance between the lenses and the higher-order coefficients, are the same. However, the inner and outer diameters of the first and second lens barrels are different.

[0059] It should be noted that any one of the examples in Embodiments 1 to 3 described below is applicable to all implementations of this application.

[0060] Example 1

[0061] like Figures 2 to 9 As shown, the visual system of Embodiment 1 is described. Figure 2 A schematic diagram of the visual system of Embodiment 1-1 in the +2D state is shown. Figure 3 A schematic diagram of the visual system of Embodiment 1-1 in -5D state is shown. Figure 4 The diagram shows the structure of the visual system of Embodiments 1-2 in the +2D state. Figure 5 The diagram shows the structure of the visual system of Embodiments 1-2 in -5D state. Figure 6 The diagram shows the structural schematics of the visual systems of Embodiments 1-3 in the +2D state. Figure 7 A schematic diagram of the visual system of Embodiments 1-3 in the -5D state is shown.

[0062] like Figures 2 to 7 As shown, the visual system includes a first lens barrel Pa, a second lens barrel Pb, a first element group, and a second element group. The first element group, along the optical axis of the visual system from the first side to the second side, sequentially includes a first lens E1, a polarizer LP, a reflective polarizing element RP, and a quarter-wave plate QWP. The polarizer LP, reflective polarizing element RP, and quarter-wave plate QWP are sequentially disposed on the second side surface of the first lens in a direction away from the first lens E1. The second element group, along the optical axis from the first side to the second side, sequentially includes a second lens E2, a reflective element BS, and a display. The display has an image surface IMG. The reflective element BS is disposed on the second side surface of the second lens; the second element group is movably disposed along the optical axis.

[0063] In this embodiment, the first lens E1, polarizer LP, reflective polarizing element RP, and quarter-wave plate QWP are housed in the first lens barrel Pa, the second lens E2 and reflective element BS are housed in the second lens barrel Pb, and the display is located on the side of the second lens barrel Pb away from the first lens barrel Pa.

[0064] In this embodiment, the light emitted from the image plane IMG passes through the second lens E2 and the quarter-wave plate QWP in sequence, and then enters the reflective polarizing element RP. After being reflected by the reflective polarizing element RP, it is transmitted towards the display side. Then, after passing through the quarter-wave plate QWP and the second lens E2 in sequence, it enters the reflective element BS. After being reflected by the reflective element BS, it is transmitted towards the human eye side. Finally, after passing through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, the polarizer LP, and the first lens E1 in sequence, it enters the human eye to form an image.

[0065] In summary, the structural parameters of the visual system of Embodiment 1 under Embodiments 1-1, 1-2, and 1-3 are shown in Table 2 (unit: millimeters mm). It should be noted that the following parameters are the same for each embodiment in both the -5D and +2D states.

[0066] Table 2

[0067] In Embodiment 1, the first lens E1 has positive optical power, the first side surface of the first lens is convex, and the second side surface of the first lens is flat; the second lens E2 has positive optical power, the first side surface of the second lens is convex, and the second side surface of the second lens is convex.

[0068] In Embodiment 1, the effective focal length f1 of the first lens is 120.6365 mm, the effective focal length f2 of the second lens is 138.3122 mm, the combined focal length fz of the first lens, polarizer, reflective polarizing element and quarter-wave plate is 120.6365 mm, the distance BFL from the second side surface of the second lens to the display on the optical axis is 0.9944 mm, when the visual system moves from +2D state to -5D state, the distance ΔL that the second element group moves along the optical axis is 2.1374 mm, and when the visual system moves from +2D state to -5D state, the change in the effective focal length of the visual system Δf is 1.1740 mm.

[0069] Table 3 shows the basic structural parameters of the visual system in Embodiment 1, where the units for radius of curvature and thickness / distance are millimeters (mm). In the table below, STO (not shown in the figure) is the aperture stop, which is located on the first side of the first lens E1.

[0070] Table 3

[0071] Table 4 shows the values ​​of D1, D2, D3, and D4 in the table above for the visual system of Embodiment 1 in +2D and -5D states. D1 represents the virtual image distance of the visual system in this embodiment. D2, D3, and D4 are all distances on the optical axis from the second side surface of the quarter-wave plate (QWP) to the first side surface of the second lens. When D1, D2, D3, and D4 are positive values, the direction is from the first side to the second side; when they are negative values, the direction is from the second side to the first side. The units of D1, D2, D3, and D4 are all millimeters (mm).

[0072] Table 4

[0073] In Embodiment 1, the first side surface of the first lens, the first side surface of the second lens, and the second side surface of the second lens are all aspherical surfaces. The surface shape of each aspherical surface can be defined using, but is not limited to, the following aspherical surface formula: Formula (1).

[0074] 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 3 above; k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 5 below gives the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for each aspherical surface in Example 1.

[0075] Table 5

[0076] Figure 8 The diagram shows the optical modulation function curves of the visual system in the +2D state according to Embodiment 1. As can be seen from the figure, the optical modulation function values ​​of the curves with a field of view of 0, 0.5, and 1.0 in the meridional direction are all relatively high, indicating that the imaging quality at this spatial frequency is good. Figure 9 The diagram shows the optical modulation function curves of the visual system in Embodiment 1 at -5D. As can be seen from the diagram, the optical modulation function values ​​of the curves at 0 field of view in the meridional direction, 0.5 field of view in the meridional direction, and 1.0 field of view in the meridional direction are all relatively high, indicating that the imaging quality at this spatial frequency is good.

[0077] Example 2

[0078] like Figures 10 to 17 As shown, the visual system of Embodiment 2 is described. Figure 10 A schematic diagram of the visual system of Embodiment 2-1 in the +2D state is shown. Figure 11 A schematic diagram of the visual system of Embodiment 2-1 in -5D state is shown. Figure 12 A schematic diagram of the visual system of Embodiment 2-2 in the +2D state is shown. Figure 13 A schematic diagram of the visual system of Embodiment 2-2 in -5D state is shown. Figure 14 The diagram shows the structure of the visual system of Embodiments 2-3 in the +2D state. Figure 15 A schematic diagram of the visual system of Embodiments 2-3 in the -5D state is shown.

[0079] like Figures 10 to 15As shown, the visual system includes a first lens barrel Pa, a second lens barrel Pb, a first element group, and a second element group. The first element group, along the optical axis of the visual system from the first side to the second side, sequentially includes a first lens E1, a polarizer LP, a reflective polarizing element RP, and a quarter-wave plate QWP. The polarizer LP, reflective polarizing element RP, and quarter-wave plate QWP are sequentially disposed on the second side surface of the first lens in a direction away from the first lens E1. The second element group, along the optical axis from the first side to the second side, sequentially includes a second lens E2, a reflective element BS, and a display. The display has an image surface IMG. The reflective element BS is disposed on the second side surface of the second lens; the second element group is movably disposed along the optical axis.

[0080] In this embodiment, the first lens E1, polarizer LP, reflective polarizing element RP, and quarter-wave plate QWP are housed in the first lens barrel Pa, the second lens E2 and reflective element BS are housed in the second lens barrel Pb, and the display is located on the side of the second lens barrel Pb away from the first lens barrel Pa.

[0081] In this embodiment, the light emitted from the image plane IMG passes through the second lens E2 and the quarter-wave plate QWP in sequence, and then enters the reflective polarizing element RP. After being reflected by the reflective polarizing element RP, it is transmitted towards the display side. Then, after passing through the quarter-wave plate QWP and the second lens E2 in sequence, it enters the reflective element BS. After being reflected by the reflective element BS, it is transmitted towards the human eye side. Finally, after passing through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, the polarizer LP, and the first lens E1 in sequence, it enters the human eye to form an image.

[0082] In summary, the structural parameters of the visual system of Embodiment 2 under Embodiments 2-1, 2-2, and 2-3 are shown in Table 6 (unit: millimeters mm). It should be noted that the following parameters are the same for each embodiment in both the -5D and +2D states.

[0083] Table 6

[0084] In Embodiment 2, the first lens E1 has positive optical power, the first side surface of the first lens is convex, and the second side surface of the first lens is flat; the second lens E2 has positive optical power, the first side surface of the second lens is convex, and the second side surface of the second lens is convex.

[0085] In Embodiment 2, the effective focal length f1 of the first lens is 143.9799 mm, the effective focal length f2 of the second lens is 132.4296 mm, the combined focal length fz of the first lens, polarizer, reflective polarizing element and quarter-wave plate is 143.9799 mm, the distance BFL from the second side surface of the second lens to the display on the optical axis is 0.8944 mm, when the visual system moves from +2D state to -5D state, the distance ΔL that the second element group moves along the optical axis is 2.3696 mm, and when the visual system moves from +2D state to -5D state, the change in the effective focal length of the visual system Δf is 1.3328 mm.

[0086] Table 7 shows the basic structural parameters of the visual system in Embodiment 2, where the units for radius of curvature and thickness / distance are millimeters (mm). In the table below, STO (not shown in the figure) is the aperture stop, which is located on the first side of the first lens E1.

[0087] Table 7

[0088] Table 8 shows the values ​​of D1, D2, D3, and D4 in the table above for the visual system of Embodiment 2 in +2D and -5D states. D1 represents the virtual image distance of the visual system in this embodiment. D2, D3, and D4 are all distances on the optical axis from the second side surface of the quarter-wave plate (QWP) to the first side surface of the second lens. When D1, D2, D3, and D4 are positive values, the direction is from the first side to the second side; when they are negative values, the direction is from the second side to the first side. The units of D1, D2, D3, and D4 are all millimeters (mm).

[0089] Table 8

[0090] Table 9 below shows the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for each aspherical surface in Example 2.

[0091] Table 9

[0092] Figure 16 The diagram shows the optical modulation function curves of the visual system in the +2D state according to Embodiment 2. As can be seen from the figure, the optical modulation function values ​​of the curves with a field of view of 0, 0.5, and 1.0 in the meridional direction are all relatively high, indicating that the imaging quality at this spatial frequency is good. Figure 17The diagram shows the optical modulation function curves of the visual system in Embodiment 2 at -5D. The optical modulation function values ​​of the curves at 0 field of view, 0.5 field of view, and 1.0 field of view in the meridional direction are all relatively high. Higher curves indicate better imaging quality at that spatial frequency.

[0093] Example 3

[0094] like Figures 18 to 25 As shown, the visual system of Embodiment 3 is described. Figure 18 A schematic diagram of the visual system of Embodiment 3-1 in the +2D state is shown. Figure 19 A schematic diagram of the visual system of Embodiment 3-1 in -5D state is shown. Figure 20 A schematic diagram of the visual system of Embodiment 3-2 in the +2D state is shown. Figure 21 A schematic diagram of the visual system of Embodiment 3-2 in -5D state is shown. Figure 22 A schematic diagram of the visual system of Embodiment 3-3 in the +2D state is shown. Figure 23 A schematic diagram of the visual system of Embodiment 3-3 in the -5D state is shown.

[0095] like Figures 18 to 23 As shown, the visual system includes a first lens barrel Pa, a second lens barrel Pb, a first element group, and a second element group. The first element group, along the optical axis of the visual system from the first side to the second side, sequentially includes a first lens E1, a polarizer LP, a reflective polarizing element RP, and a quarter-wave plate QWP. The polarizer LP, reflective polarizing element RP, and quarter-wave plate QWP are sequentially disposed on the second side surface of the first lens in a direction away from the first lens E1. The second element group, along the optical axis from the first side to the second side, sequentially includes a second lens E2, a reflective element BS, and a display. The display has an image surface IMG. The reflective element BS is disposed on the second side surface of the second lens; the second element group is movably disposed along the optical axis.

[0096] In this embodiment, the first lens E1, polarizer LP, reflective polarizing element RP, and quarter-wave plate QWP are housed in the first lens barrel Pa, the second lens E2 and reflective element BS are housed in the second lens barrel Pb, and the display is located on the side of the second lens barrel Pb away from the first lens barrel Pa.

[0097] In this embodiment, the light emitted from the image plane IMG passes through the second lens E2 and the quarter-wave plate QWP in sequence, and then enters the reflective polarizing element RP. After being reflected by the reflective polarizing element RP, it is transmitted towards the display side. Then, after passing through the quarter-wave plate QWP and the second lens E2 in sequence, it enters the reflective element BS. After being reflected by the reflective element BS, it is transmitted towards the human eye side. Finally, after passing through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, the polarizer LP, and the first lens E1 in sequence, it enters the human eye to form an image.

[0098] In summary, the structural parameters of the visual system of Embodiment 3 under Embodiments 3-1, 3-2, and 3-3 are shown in Table 10 (unit: mm). It should be noted that the following parameters are the same for each embodiment in the -5D and +2D states.

[0099] Table 10

[0100] In Embodiment 3, the first lens E1 has positive optical power, the first side surface of the first lens is convex, and the second side surface of the first lens is flat; the second lens E2 has positive optical power, the first side surface of the second lens is convex, and the second side surface of the second lens is convex.

[0101] In Embodiment 3, the effective focal length f1 of the first lens is 132.4572 mm, the effective focal length f2 of the second lens is 147.8224 mm, the combined focal length fz of the first lens, polarizer, reflective polarizing element and quarter-wave plate is 132.4572 mm, the distance BFL from the second side surface of the second lens to the display on the optical axis is 0.8944 mm, when the visual system moves from +2D state to -5D state, the distance ΔL that the second element group moves along the optical axis is 2.3870 mm, and when the visual system moves from +2D state to -5D state, the change in the effective focal length of the visual system Δf is 1.2855 mm.

[0102] Table 11 shows the basic structural parameters of the visual system in Embodiment 3, where the units for radius of curvature and thickness / distance are millimeters (mm). In the table below, STO (not shown in the figure) is the aperture stop, which is located on the first side of the first lens E1.

[0103] Table 11

[0104] Table 12 shows the values ​​of D1, D2, D3, and D4 in the table above for the visual system of Embodiment 3 in +2D and -5D states. D1 represents the virtual image distance of the visual system in this embodiment. D2, D3, and D4 are all distances on the optical axis from the second side surface of the quarter-wave plate (QWP) to the first side surface of the second lens. When D1, D2, D3, and D4 are positive, the direction is from the first side to the second side; when they are negative, the direction is from the second side to the first side. The units of D1, D2, D3, and D4 are all millimeters (mm).

[0105] Table 12

[0106] Table 13 below gives the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for each aspherical surface in Example 3.

[0107] Table 13

[0108] Figure 24 The diagram shows the optical modulation function curves of the visual system in the +2D state of Embodiment 3. As can be seen from the figure, the optical modulation function values ​​of the curves with a field of view of 0, 0.5, and 1.0 in the meridional direction are all relatively high, indicating that the imaging quality at this spatial frequency is good. Figure 25 The diagram shows the optical modulation function curves of the visual system in Example 3 at -5D. As can be seen from the diagram, the optical modulation function values ​​of the curves at 0 field of view in the meridional direction, 0.5 field of view in the meridional direction, and 1.0 field of view in the meridional direction are all relatively high, indicating that the imaging quality at this spatial frequency is good.

[0109] In summary, each embodiment of Examples 1 to 3 satisfies the relationships shown in Table 14. The following conditional expressions have the same values ​​in both the -5D and +2D states for each embodiment.

[0110] Table 14

[0111] Table 15 shows the effective focal length and other parameters of each lens in each embodiment.

[0112] Table 15

[0113] This application also provides an imaging device, whose electronic photosensitive element can be a photocoupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The imaging device can be a stand-alone imaging device such as a digital camera, or an imaging module integrated into a mobile electronic device such as a mobile phone. The imaging device is equipped with the visual system described above.

[0114] Alternatively, the imaging device can be a VR device or an AR device.

[0115] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0116] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0117] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0118] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A visual system, characterized in that, The scope includes a first lens barrel, a second lens barrel, a first element group, and a second element group, wherein at least a portion of the first element group is housed in the first lens barrel, and at least a portion of the second element group is housed in the second lens barrel. The first element group includes, in sequence from the first side to the second side along the optical axis of the visual system, a first lens, a polarizer, a reflective polarizing element, and a quarter-wave plate. The polarizer, the reflective polarizing element, and the quarter-wave plate are sequentially disposed on the second side surface of the first lens in a direction away from the first lens. The first lens has positive optical power, the first side surface of the first lens is convex, and the second side surface of the first lens is planar. The second element group includes, in sequence from the first side to the second side along the optical axis, a second lens, a reflective element, and a display. The reflective element is disposed on the second side surface of the second lens. The second lens has positive optical power, and both the first and second side surfaces of the second lens are convex. The second element group is movably disposed along the optical axis. The visual system contains two lenses. The first side refers to the side of the visual system facing the human eye, and the second side refers to the side of the visual system facing the display; the edge of the first side surface of the first lens rests on the inner wall of the end of the first lens barrel facing the human eye; The radius of curvature R1 of the first side surface of the first lens and the minimum inner diameter damin of the first lens barrel satisfy the following condition: 2.07≤R1 / damin≤2.70; The distance La between the first side surface of the first lens barrel and the second side surface of the first lens barrel on the optical axis, the distance Lb between the first side surface of the second lens barrel and the second side surface of the second lens barrel on the optical axis, and the distance ΔL that the second element group moves along the optical axis when the visual system moves from +2D state to -5D state satisfy the following: 3.99≤(La+Lb) / ΔL≤5.99; The outer diameter Das of the first side surface of the first lens barrel and the center thickness CT1 of the first lens on the optical axis satisfy the following condition: 8.51≤Das / CT1≤10.

20.

2. The visual system according to claim 1, characterized in that, The central thickness CT2 of the second lens on the optical axis and the distance Lb between the first side surface of the second lens barrel and the second side surface of the second lens barrel on the optical axis satisfy the following condition: 0.94≤CT2 / Lb≤1.

47.

3. The visual system according to claim 1, characterized in that, The radius of curvature R4 of the second side surface of the second lens and the minimum inner diameter dbmin of the second lens barrel satisfy the following condition: -2.91≤R4 / dbmin≤-2.

59.

4. The visual system according to claim 1, characterized in that, The inner diameter dbs of the first side surface of the second lens barrel, the inner diameter dbm of the second side surface of the second lens barrel, and the change in the effective focal length Δf of the visual system when the visual system moves from the +2D state to the -5D state satisfy the following: 2.18≤(dbs-dbm) / Δf≤5.

43.

5. The visual system according to claim 1, characterized in that, The distance La between the first side surface and the second side surface of the first lens barrel on the optical axis, the combined focal length fz of the first lens, the polarizer, the reflective polarizing element and the quarter-wave plate and the effective focal length f2 of the second lens satisfy the following: 3.31mm≤La×(fz / f2)≤6.50mm.

6. The visual system according to claim 1, characterized in that, The radius of curvature R3 of the first side surface of the second lens and the outer diameter Dbs of the first side surface of the second lens barrel satisfy the following condition: 4.82≤R3 / Dbs≤7.

68.

7. The visual system according to claim 1, characterized in that, The inner diameter dam of the second side surface of the first lens barrel, the inner diameter das of the first side surface of the first lens barrel, and the distance ΔL that the second element group moves along the optical axis when the visual system moves from +2D state to -5D state satisfy the following: 2.43≤(dam-das) / ΔL≤5.

53.

8. The visual system according to claim 1, characterized in that, The effective focal length f1 of the first lens and the outer diameter Dam of the second side surface of the first lens barrel satisfy the following condition: 2.76≤f1 / Dam≤3.

29.

9. The visual system according to claim 1, characterized in that, The minimum inner diameter dbmin of the second lens barrel, the minimum inner diameter damin of the first lens barrel, and the distance ΔL that the second element group moves along the optical axis when the visual system moves from +2D state to -5D state satisfy the following condition: 1.49≤(dbmin-damin) / ΔL≤4.

19.

10. The visual system according to claim 1, characterized in that, The outer diameter Dbm of the second side surface of the second lens barrel, the inner diameter dbm of the second side surface of the second lens barrel, and the distance BFL from the second side surface of the second lens to the display on the optical axis satisfy the following condition: 3.61≤(Dbm-dbm) / BFL≤7.

20.

11. The visual system according to claim 1, characterized in that, The minimum inner diameter damin of the first lens barrel and the distance La between the first side surface and the second side surface of the first lens barrel on the optical axis satisfy the following condition: 3.97≤damin / La≤9.

26.

12. The visual system according to any one of claims 1 to 11, characterized in that, The minimum inner diameter dbmin of the second lens barrel and the distance Lb between the first side surface and the second side surface of the second lens barrel on the optical axis satisfy the following condition: 5.35≤dbmin / Lb≤8.

89.

13. The visual system according to any one of claims 1 to 11, characterized in that, The effective focal length f2 of the second lens, the refractive index N2 of the second lens, and the inner diameter dbs of the first side surface of the second lens barrel satisfy the following condition: 1.94≤(f2 / N2) / dbs≤2.22.

Images