visual system

Abstract

The present invention provides a visual system, including an optical element group and a lens barrel group, wherein the first element group includes a first lens, a polarizer, a reflective polarizing element, and a quarter-wave plate, and the second element group includes a second lens, a partially reflective element, and a display; the lens barrel group includes a first lens barrel and a second lens barrel, the first element group rests on the first lens barrel, and at least a portion of the second element group rests on the second lens barrel; the change Δf of the effective focal length of the visual system when it moves from a +2D state to a -5D state, the outer diameter Dbs of the first side surface of the second lens barrel, and the outer diameter Dbm of the second side surface of the second lens barrel satisfy the following conditions: 0.33≤Δf / (Dbs-Dbm)≤1.46; the maximum thickness Lb from the first side surface of the second lens barrel to the second side surface of the second 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 conditions: 1.04≤Lb / ΔL≤2.08. The present invention solves the problem of poor assembly stability of visual systems in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of head-mounted devices, and in particular to a visual system. Background Art

[0002] With the growing popularity of the "metaverse" concept, augmented reality (AR) and virtual reality (VR) technologies are experiencing new development opportunities. To provide a more realistic and immersive visual experience, VR devices require advanced optical solutions to meet the requirements of high resolution and wearing comfort. Existing visual systems, when assembling lenses within a limited space, are limited by the sensitivity of the lens surface, resulting in significant variations in lens surface shape. This leads to poor assembly stability and significantly reduced assembly yield. Therefore, controlling the shape of the lens barrel and the spatial allocation within the visual system, while balancing miniaturization and assembly stability, is a crucial issue. Summary of the Invention

[0003] The main purpose of the present invention is to provide a visual system to solve the problem of poor assembly stability of the visual system in the prior art.

[0004] To achieve the above-mentioned purpose, according to one aspect of the present invention, a visual system is provided, which comprises: an optical element group, the optical element group comprising a first element group and a second element group, along the direction of the optical axis of the visual system, the first element group comprises, from the first side to the second side, a first lens, a polarizer, a reflective polarizing element and a quarter-wave plate, the first lens has positive optical power, the first side surface of the first lens is a convex surface, and the second side surface of the first lens is a plane, the second element group comprises, from the first side to the second side, a second lens, a partially reflecting element and a display, the second lens has positive optical power, the first side surface of the second lens is a convex surface, and the second side surface of the second lens is a convex surface; a barrel group, the barrel group comprising a first barrel and a second barrel, the first barrel and the second barrel, the second lens have positive optical power, the first side surface of the second lens is a convex surface, and the second side surface of the second lens is a convex surface; An element group rests on the first lens barrel, and at least a portion of the second element group rests on the second lens barrel; wherein the second element group is capable of moving along the direction of the optical axis to approach or move away from the first element group; the change Δf of the effective focal length of the visual system when it moves from the +2D state to the -5D state, the outer diameter Dbs of the first side surface of the second lens barrel, and the outer diameter Dbm of the second side surface of the second lens barrel satisfy the following: 0.33≤Δf / (Dbs-Dbm)≤1.46; the maximum thickness Lb from the first side surface of the second lens barrel to the second side surface of the second lens barrel, and the distance ΔL that the second element group moves along the direction of the optical axis when the visual system moves from the +2D state to the -5D state satisfy the following: 1.04≤Lb / ΔL≤2.08.

[0005] According to another aspect of the present invention, a visual system is provided, which includes: an optical element group, the optical element group includes a first element group and a second element group, along the direction of the optical axis of the visual system, the first element group includes a first lens, a polarizer, a reflective polarizing element and a quarter wave plate in sequence from the first side to the second side, 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 flat, the second element group includes a second lens, a partially reflecting element and a display in sequence from the first side to the second side, 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; a lens barrel group, the lens barrel group includes The invention comprises a first lens barrel and a second lens barrel, the first element group rests on the first lens barrel, and at least a part of the second element group rests on the second lens barrel; wherein the second element group can move along the direction of the optical axis to approach or move away from the first element group; the change Δf of the effective focal length of the visual system from the +2D state to the -5D state, the outer diameter Dbs of the first side surface of the second lens barrel, and the outer diameter Dbm of the second side surface of the second lens barrel satisfy the following relationship: 0.33≤Δf / (Dbs-Dbm)≤1.46; the curvature radius R1 of the first side surface of the first lens and the inner diameter das of the first side surface of the first lens barrel satisfy the following relationship: 2.22≤R1 / das≤2.87.

[0006] Furthermore, the maximum thickness La from the first side surface of the first lens barrel to the second side surface of the first lens barrel, the center thickness CT1 of the first lens on the optical axis, the center thickness CTL of the polarizer on the optical axis, the center thickness CTR of the reflective polarizing element on the optical axis, and the center thickness CTQ of the quarter-wave plate on the optical axis satisfy the following: 1.07≤La / (CT1+CTL+CTR+CTQ)≤2.33.

[0007] Furthermore, a curvature radius R1 of the first side surface of the first lens and an inner diameter das of the first side surface of the first lens barrel satisfy the following relationship: 2.22≤R1 / das≤2.87.

[0008] Furthermore, the combined focal length fz of the first lens, the polarizer, the reflective polarizing element, and the quarter-wave plate and the outer diameter Dam of the second side surface of the first lens barrel satisfy the following relationship: 3.06≤fz / Dam≤4.27.

[0009] Furthermore, the curvature radius R3 of the first side surface of the second lens, the curvature radius R4 of the second side surface of the second lens, and the inner diameter dbs of the first side surface of the second lens barrel satisfy: 0.69≤(R3+R4) / dbs≤3.04.

[0010] Furthermore, the inner diameter dbm of the second side surface of the second 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: 10.13≤dbm / ΔL≤10.94.

[0011] Furthermore, the inner diameter dbs of the first side surface of the second barrel, the inner diameter dbm of the second side surface of the second barrel, and the center thickness CT2 of the second lens on the optical axis satisfy: 0.81≤(dbs−dbm) / CT2≤1.42.

[0012] Furthermore, the effective focal length f1 of the first lens, the refractive index N1 of the first lens, and the inner diameter dam of the second side surface of the first lens barrel satisfy the following relationship: 2.18≤(f1 / N1) / dam≤2.90.

[0013] Furthermore, when the visual system moves from the +2D state to the -5D state, the distance ΔL moved by the second element group along the optical axis, the outer diameter Dam of the second side surface of the first lens barrel, and the outer diameter Das of the first side surface of the first lens barrel satisfy the following relationship: 5.16mm≤ΔL×(Dam / Das)≤5.80mm.

[0014] Furthermore, the maximum thickness La from the first side surface to the second side surface of the first lens barrel and the change Δf of the effective focal length of the visual system from the +2D state to the -5D state satisfy the following relationship: 1.68≤La / Δf≤4.34.

[0015] Furthermore, the effective focal length f2 of the second lens and the outer diameter Dbs of the first side surface of the second lens barrel satisfy the following relationship: 2.63≤f2 / Dbs≤3.23.

[0016] Furthermore, a maximum thickness Lb from the first side surface of the second lens barrel to the second side surface of the second lens barrel and a refractive index N2 of the second lens satisfy the following relationship: 3.34 mm ≤ Lb / N2 ≤ 6.17 mm.

[0017] Furthermore, a maximum thickness La from the first side surface of the first lens barrel to the second side surface of the first lens barrel, a maximum thickness Lb from the first side surface of the second lens barrel to the second side surface of the second lens barrel, a center thickness CT1 of the first lens on the optical axis, and a center thickness CT2 of the second lens on the optical axis satisfy the following: 1.07≤(La+Lb) / (CT1+CT2)≤1.95.

[0018] Furthermore, the change Δf of the effective focal length of the visual system from the +2D state to the -5D state, the inner diameter dbs of the first side surface of the second lens barrel, and the inner diameter dam of the second side surface of the first lens barrel satisfy: 1.00≤Δf / (dbs-dam)≤6.29.

[0019] The technical solution of the present invention is applied, and the visual system includes an optical element group and a lens barrel group, the optical element group includes a first element group and a second element group, along the direction of the optical axis of the visual system, the first element group includes a first lens, a polarizer, a reflective polarizing element and a quarter wave plate in sequence from the first side to the second side, the first lens has positive focal length, the first side surface of the first lens is a convex surface, and the second side surface of the first lens is a plane, the second element group includes a second lens, a partial reflective element and a display in sequence from the first side to the second side, the second lens has positive focal length, the first side surface of the second lens is a convex surface, and the second side surface of the second lens is a convex surface; the lens barrel group includes a first lens barrel and a second lens barrel, and the first element group is supported on the first lens barrel. On the barrel, at least a portion of the second element group rests on the second lens barrel; wherein the second element group can move in the direction of the optical axis to approach or move away from the first element group; the change Δf of the effective focal length of the visual system when it moves from the +2D state to the -5D state, the outer diameter Dbs of the first side surface of the second lens barrel, and the outer diameter Dbm of the second side surface of the second lens barrel satisfy the following: 0.33≤Δf / (Dbs-Dbm)≤1.46; the maximum thickness Lb from the first side surface of the second lens barrel to the second side surface of the second lens barrel, and the distance ΔL that the second element group moves in the direction of the optical axis when the visual system moves from the +2D state to the -5D state satisfy the following: 1.04≤Lb / ΔL≤2.08.

[0020] In the present application, by rationally configuring the visual system, while ensuring the miniaturization of the second lens barrel, the stability of the assembly of the first lens and the second lens will be reduced. By controlling Δf / (Dbs-Dbm) and Lb / ΔL within a certain range, the surface shape and thickness of the second lens barrel along the optical axis are constrained. While ensuring sufficient space for optical path folding during a wide range of diopter adjustment, the second lens can stably rest on the second lens barrel and the first lens can stably rest on the first lens barrel, thereby reducing the risk of deformation of the assembly of the first and second lenses and improving the stability of the assembly of the first and second lenses. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0022] Figure 1 A schematic diagram showing some parameters of a visual system according to any optional embodiment of the present invention is shown;

[0023] Figure 2 It shows a schematic structural diagram of the visual system of the first embodiment of the present invention in the first state;

[0024] Figure 3It shows a schematic structural diagram of the visual system of the first embodiment of the present invention in the second state;

[0025] Figure 4 FIG1 shows an MTF curve diagram of the visual system in the first state according to the first embodiment of the present invention;

[0026] Figure 5 FIG2 shows an MTF curve diagram of the visual system of the first embodiment of the present invention in the second state;

[0027] Figure 6 It shows a schematic structural diagram of the visual system of the second embodiment of the present invention in the first state;

[0028] Figure 7 It shows a schematic structural diagram of the visual system of the second embodiment of the present invention in the second state;

[0029] Figure 8 It shows a schematic structural diagram of the visual system of the third embodiment of the present invention in the first state;

[0030] Figure 9 It shows a schematic structural diagram of the visual system of the third embodiment of the present invention in the second state;

[0031] Figure 10 It shows a schematic structural diagram of the visual system of the fourth embodiment of the present invention in the first state;

[0032] Figure 11 It shows a schematic structural diagram of the visual system of the fourth embodiment of the present invention in the second state;

[0033] Figure 12 FIG1 shows an MTF curve diagram of the visual system of the fourth embodiment of the present invention in the first state;

[0034] Figure 13 The MTF curve diagram of the visual system of the fourth embodiment of the present invention in the second state is shown.

[0035] Figure 14 It shows a schematic structural diagram of the visual system of the fifth embodiment of the present invention in the first state;

[0036] Figure 15 It shows a schematic structural diagram of the visual system of the fifth embodiment of the present invention in the second state;

[0037] Figure 16 It shows a schematic structural diagram of the visual system of embodiment 6 of the present invention in the first state;

[0038] Figure 17 It shows a schematic structural diagram of the visual system of the sixth embodiment of the present invention in the second state;

[0039] Figure 18 It shows a schematic structural diagram of the visual system of the seventh embodiment of the present invention in the first state;

[0040] Figure 19 It shows a schematic structural diagram of the visual system of the seventh embodiment of the present invention in the second state;

[0041] Figure 20 FIG2 shows an MTF curve diagram of the visual system of Example 7 of the present invention in the first state;

[0042] Figure 21 FIG2 shows an MTF curve diagram of the visual system of Example 7 of the present invention in the second state;

[0043] Figure 22 It shows a schematic structural diagram of the visual system of the eighth embodiment of the present invention in the first state;

[0044] Figure 23 It shows a schematic structural diagram of the visual system of the eighth embodiment of the present invention in the second state;

[0045] Figure 24 It shows a schematic structural diagram of the visual system of the ninth embodiment of the present invention in the first state;

[0046] Figure 25 A schematic structural diagram of the visual system of embodiment 9 of the present invention in the second state is shown.

[0047] The above drawings include the following reference numerals:

[0048] Pa, first lens barrel; Pb, second lens barrel; E1, first lens; LP, polarizer; RP, reflective polarizer; QWP, quarter-wave plate; E2, second lens; BS, partially reflecting element; IMG, image plane. DETAILED DESCRIPTION

[0049] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0050] 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 ordinary technicians in the technical field to which this application belongs.

[0051] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity direction; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above directional words are not used to limit the present invention.

[0052] It should be noted that in this specification, the terms "first," "second," "third," etc., are used solely to distinguish one feature from another and do not limit the features. Thus, the first lens discussed below could also be referred to as the second lens or the third lens without departing from the teachings of this application.

[0053] In the drawings, the thickness, size, and shape of the lenses are slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical and aspherical surfaces shown in the drawings are provided by way of example. That is, the shapes of the spherical and aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0054] In this article, the paraxial region refers to the area near the optical axis. If a lens surface is convex and the location of the convex surface is undefined, it indicates that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the location of the concave surface is undefined, it indicates that the lens surface is concave at least in the paraxial region. The surface shape in the paraxial region can be determined according to the judgment method commonly used by those skilled in the art, using the positive or negative R value (R refers to the radius of curvature of the paraxial region, typically the R value in the lens database in optical software) to determine whether it is convex or concave. For the eye-side surface, a positive R value indicates a convex surface, and a negative R value indicates a concave surface. For the display-side surface, a positive R value indicates a concave surface, and a negative R value indicates a convex surface.

[0055] In order to solve the problem of poor assembly stability of the visual system in the prior art, the present invention provides a visual system.

[0056] First embodiment

[0057] like Figures 1 to 25As shown, the visual system includes an optical element group and a lens barrel group, the optical element group includes a first element group and a second element group, along the direction of the optical axis of the visual system, the first element group includes a first lens, a polarizer, a reflective polarizing element and a quarter wave plate in sequence from the first side to the second side, 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 flat, the second element group includes a second lens, a partial reflection element and a display in sequence from the first side to the second side, 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 lens barrel group includes a first lens barrel and a second lens barrel, the first element group rests on the first lens barrel, the second element group rests on the first lens barrel, and the second element group rests on the first lens barrel. At least a portion of the second element group rests on the second lens barrel; wherein the second element group can move along the direction of the optical axis to approach or move away from the first element group; the change Δf of the effective focal length of the visual system when it moves from the +2D state to the -5D state, the outer diameter Dbs of the first side surface of the second lens barrel, and the outer diameter Dbm of the second side surface of the second lens barrel satisfy the following: 0.33≤Δf / (Dbs-Dbm)≤1.46; the maximum thickness Lb from the first side surface of the second lens barrel to the second side surface of the second lens barrel, and the distance ΔL that the second element group moves along the direction of the optical axis when the visual system moves from the +2D state to the -5D state satisfy the following: 1.04≤Lb / ΔL≤2.08.

[0058] In the present application, by rationally configuring the visual system, while ensuring the miniaturization of the second lens barrel, the stability of the assembly of the first lens and the second lens will be reduced. By controlling Δf / (Dbs-Dbm) and Lb / ΔL within a certain range, the surface shape and thickness of the second lens barrel along the optical axis are constrained. While ensuring sufficient space for optical path folding during a wide range of diopter adjustment, the second lens can stably rest on the second lens barrel and the first lens can stably rest on the first lens barrel, thereby reducing the risk of deformation of the assembly of the first and second lenses and improving the stability of the assembly of the first and second lenses.

[0059] Table 1 below compares the sensitivity of the visual system's assembly profile change for Comparative Example 1, Comparative Example 2, and Alternative Solution 1 of this application. The displacements of the center and edge points of the first side surface of the first lens, the second side surface of the first lens, the first side surface of the second lens, and the second side surface of the second lens of the visual system were measured, and the assembly profile changes were summarized to intuitively determine the degree of assembly deformation of the visual system for different solutions.

[0060] Table 1

[0061]

[0062] As can be seen from Table 1, for the visual system of Comparative Example 1, under the conditions of Δf / (Dbs-Dbm) = 1.8 and Lb / ΔL = 2.4, the center points and edge points of each surface of the first and second lenses undergo significant displacement, resulting in a significant degree of change in the surface configuration. For the visual system of Comparative Example 2, under the conditions of Δf / (Dbs-Dbm) = 0.1 and Lb / ΔL = 0.6, the center points and edge points of each surface of the first and second lenses undergo significant displacement, resulting in a significant degree of change in the surface configuration. In the optional solution 1 of the present application, under the conditions of Δf / (Dbs-Dbm)=0.92 and Lb / ΔL=1.14, that is, when 0.33≤Δf / (Dbs-Dbm)≤1.46 and 1.04≤Lb / ΔL≤2.08 are satisfied, the displacement of the center point and edge point of the lens surface are well controlled, and the shape change after assembly is very small, which can effectively ensure the stability of the assembly and the reliability of the visual system.

[0063] In this embodiment, the maximum thickness La from the first side surface of the first lens barrel to the second side surface of the first lens barrel, the center thickness CT1 of the first lens on the optical axis, the center thickness CTL of the polarizer on the optical axis, the center thickness CTR of the reflective polarizer on the optical axis, and the center thickness CTQ of the quarter-wave plate on the optical axis satisfy the following relationship: 1.07 ≤ La / (CT1+CTL+CTR+CTQ) ≤ 2.33. By limiting La / (CT1+CTL+CTR+CTQ) to a reasonable range, the length of the first lens barrel can be controlled, and the effective focal length of the visual system as a whole can be reduced, thereby achieving a miniaturized design for the head-mounted device. Furthermore, the wall thickness of the first lens barrel can be indirectly controlled, ensuring the feasibility of processing and forming the first lens barrel.

[0064] In this embodiment, the radius of curvature R1 of the first side surface of the first lens and the inner diameter das of the first side surface of the first lens barrel satisfy the following relationship: 2.22 ≤ R1 / das ≤ 2.87. By limiting R1 / das to a reasonable range, the optical power of the first lens is controlled, thereby facilitating correction of aberrations in the visual system. Furthermore, the shape of the first lens is constrained, thereby reducing its sensitivity and improving the assembly yield of the visual system.

[0065] In this embodiment, the combined focal length fz of the first lens, polarizer, reflective polarizer, and quarter-wave plate, and the outer diameter Dam of the second side surface of the first lens barrel satisfy the following relationship: 3.06 ≤ fz / Dam ≤ 4.27. By limiting fz / Dam to a reasonable range, the image height of the visual system is controlled, constraining screen size. Furthermore, the volume of the first lens barrel is controlled, facilitating its miniaturized design and, consequently, facilitating the adaptation of the visual system to a miniaturized head-mounted device.

[0066] In this embodiment, the radius of curvature R3 of the first side surface of the second lens, the radius of curvature R4 of the second side surface of the second lens, and the inner diameter dbs of the first side surface of the second lens barrel satisfy the following relationship: 0.69 ≤ (R3 + R4) / dbs ≤ 3.04. By limiting (R3 + R4) / dbs to a reasonable range, the shape of the second lens is constrained, which helps reduce the sensitivity of the second lens, thereby improving the assembly yield of the visual system. Furthermore, the optical power of the second lens is controlled, which helps correct aberrations of the visual system.

[0067] In this embodiment, the relationship between the inner diameter (dBm) of the second side surface of the second 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 satisfies the following: 10.13 ≤ dBm / ΔL ≤ 10.94. By limiting the dBm / ΔL ratio to a reasonable range, the size of the head-mounted device can be reduced while ensuring the performance of the visual system. This also reduces imaging aberrations and chromatic aberration, thereby improving image clarity in the external field of view.

[0068] 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 center thickness CT2 of the second lens on the optical axis satisfy the following relationship: 0.81 ≤ (dbs - dbm) / CT2 ≤ 1.42. By limiting (dbs - dbm) / CT2 to a reasonable range, the thickness ratio of the second lens can be controlled, facilitating the molding and gluing of the second lens. Furthermore, the stability of the second lens assembly is improved, thereby increasing the assembly yield of the visual system.

[0069] In this embodiment, the effective focal length f1 of the first lens, the refractive index N1 of the first lens, and the inner diameter dam of the second side surface of the first lens barrel satisfy the following relationship: 2.18 ≤ (f1 / N1) / dam ≤ 2.90. By limiting (f1 / N1) / dam to a reasonable range, it is possible to more rationally select optical materials with conventional performance, facilitating correction of chromatic aberration in the visual system. Furthermore, it is possible to control the optical power of the first and second lenses. Combined with the air gap between the two lenses, the focal length of the visual system can be controlled, thereby constraining the visual system's field of view and meeting the wide-angle requirements of the head-mounted device.

[0070] In this embodiment, 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, the outer diameter Dam of the second side surface of the first lens barrel, and the outer diameter Das of the first side surface of the first lens barrel satisfy the following relationship: 5.16 mm ≤ ΔL × (Dam / Das) ≤ 5.80 mm. By limiting ΔL × (Dam / Das) to a reasonable range, the optical power of the visual system is effectively allocated, and while maintaining the effective focal length of the visual system, the aberrations of the visual system are corrected, thereby improving imaging quality.

[0071] In this embodiment, the maximum thickness La from the first side surface of the first lens barrel to the second side surface of the first lens barrel and the change Δf in the effective focal length of the visual system from the +2D state to the -5D state satisfy the following relationship: 1.68 ≤ La / Δf ≤ 4.34. By limiting La / Δf to a reasonable range, the thickness of the first lens barrel is constrained, ensuring its formability. Furthermore, the overall length of the visual system along the optical axis is indirectly constrained, contributing to a slimmer and lighter head-mounted device.

[0072] In this embodiment, the effective focal length f2 of the second lens and the outer diameter Dbs of the first side surface of the second lens barrel satisfy the following relationship: 2.63 ≤ f2 / Dbs ≤ 3.23. By limiting f2 / Dbs to a reasonable range, assembly stability is improved while limiting the volume of the second lens barrel, facilitating a miniaturized head-mounted device design. Furthermore, the effective focal length and maximum field of view of the second lens are controlled, thereby controlling the image height of the visual system and limiting screen size.

[0073] In this embodiment, the maximum thickness Lb from the first side surface of the second lens barrel to the second side surface of the second lens barrel and the refractive index N2 of the second lens satisfy the following relationship: 3.34mm≤Lb / N2≤6.17mm. By limiting Lb / N2 to a reasonable range, the size of the second lens barrel is restricted while also allowing for the more appropriate selection of optical materials with conventional performance, facilitating correction of chromatic aberration in the visual system.

[0074] In this embodiment, the maximum thickness La from the first side surface of the first lens barrel to the second side surface of the first lens barrel, the maximum thickness Lb from the first side surface of the second lens barrel to the second side surface of the second lens barrel, the center thickness CT1 of the first lens on the optical axis, and the center thickness CT2 of the second lens on the optical axis satisfy the following relationship: 1.07≤(La+Lb) / (CT1+CT2)≤1.95. By limiting (La+Lb) / (CT1+CT2) to a reasonable range, the size of the entire lens barrel assembly can be restricted, facilitating a slimmer and lighter head-mounted device. Furthermore, the effective focal length and maximum field of view of the visual system are controlled, achieving wide-angle imaging while improving image quality.

[0075] In this embodiment, the change in effective focal length Δf of the visual system from the +2D state to the -5D state, the inner diameter dbs of the first side surface of the second lens barrel, and the inner diameter dam of the second side surface of the first lens barrel satisfy the following relationship: 1.00 ≤ Δf / (dbs-dam) ≤ 6.29. By limiting Δf / (dbs-dam) to a reasonable range, the shapes of the first and second lens barrels are constrained, and the wall thicknesses of the first and second lens barrels are controlled, facilitating the miniaturization of the visual system. Furthermore, the optical power of the visual system is effectively distributed, correcting system aberrations while maintaining the effective focal length of the visual system, thereby improving imaging quality.

[0076] Second embodiment

[0077] like Figures 1 to 25 As shown, the visual system includes an optical element group and a lens barrel group, the optical element group includes a first element group and a second element group, along the direction of the optical axis of the visual system, the first element group includes a first lens, a polarizer, a reflective polarizing element and a quarter wave plate in sequence from the first side to the second side, the first lens has positive optical power, the first side surface of the first lens is a convex surface, and the second side surface of the first lens is a plane, the second element group includes a second lens, a partial reflection element and a display in sequence from the first side to the second side, the second lens has positive optical power, the first side surface of the second lens is a convex surface, and the second side surface of the second lens is a convex surface; the lens barrel group includes a first lens barrel and a second lens barrel , the first element group rests on the first lens barrel, and at least a portion of the second element group rests on the second lens barrel; wherein the second element group can move along the direction of the optical axis to approach or move away from the first element group; the change Δf of the effective focal length of the visual system from the +2D state to the -5D state, the outer diameter Dbs of the first side surface of the second lens barrel, and the outer diameter Dbm of the second side surface of the second lens barrel satisfy: 0.33≤Δf / (Dbs-Dbm)≤1.46; the curvature radius R1 of the first side surface of the first lens and the inner diameter das of the first side surface of the first lens barrel satisfy: 2.22≤R1 / das≤2.87.

[0078] This application rationally configures the visual system, and on the basis of meeting the miniaturization of the second lens barrel, the stability of the assembly of the first lens and the second lens will deteriorate. By controlling Δf / (Dbs-Dbm) and R1 / das within a certain range, the surface shape of the first lens barrel and the second lens barrel and the thickness along the optical axis are constrained, while indirectly constraining the shape of the first lens and the second lens, which can reduce the sensitivity of the lens, ensure that the second lens can stably support the second lens barrel and the first lens can stably support the first lens barrel, reduce the risk of deformation of the assembly of the first lens and the second lens, improve the stability of the assembly of the first lens and the second lens, and thus improve the assembly yield of the visual system. In addition, the optical power of the first lens can be controlled to correct the aberration of the visual system.

[0079] It should be noted that this embodiment may also include other parameter formulas in the first embodiment, which will not be described one by one here.

[0080] In the present application, at least one of the first and second lenses has an aspheric surface. Aspheric lenses are characterized by a continuously varying curvature from the center to the periphery. Unlike spherical lenses, which have a constant curvature from the center to the periphery, aspheric lenses have a more optimized curvature radius, offering advantages such as improved distortion and astigmatism. The use of aspheric lenses minimizes aberrations that occur during imaging, thereby improving image quality.

[0081] However, those skilled in the art will appreciate that the number of lenses comprising the visual system can be varied to achieve the various results and advantages described herein without departing from the technical solutions claimed herein. For example, while two lenses are described as an example in the embodiments, the visual system is not limited to comprising two lenses. If desired, the visual system can also include other numbers of lenses.

[0082] Figure 1 Parameters such as das and Dbm are marked to clearly and intuitively understand their meaning. To facilitate the display of the visual system structure and specific face shapes, these parameters will not be reflected in the figures when describing specific examples later.

[0083] It should be noted that in the following embodiments, the visual system of the same embodiment has a first state and a second state. The curvature radius, center thickness and high-order image coefficient of the first lens and the second lens in these two states are the same, but the spacing distance between the first element group and the second element group, the lens barrel and other parameters are different.

[0084] It should be noted that the movement of the second element group of the visual system along the optical axis toward the first element group results in a change in diopter. The diopter of the visual system is +2D in the first state and -5D in the second state. The first state indicates that the visual system is suitable for users with a hyperopia of 200 degrees, while the second state indicates that the visual system is suitable for users with a myopia of 500 degrees. The visual system also has other states besides the first and second states, and the diopter of the visual system in these other states can range from +2D to -5D.

[0085] It should be noted that the first side refers to the human eye side, the second side refers to the display side, and the image plane is located on the display.

[0086] The following further describes examples of specific surface shapes and parameters of the visual system applicable to the above-mentioned embodiment with reference to the accompanying drawings.

[0087] Example 1

[0088] like Figure 2 and Figure 3 As shown, the structures of the visual system of embodiment 1 of the present application in the first state and the second state are described respectively.

[0089] like Figure 2 and Figure 3 As shown, the first element group rests on the first lens barrel Pa, and at least a portion of the second element group rests on the second lens barrel Pb. The first element group includes, from the first side to the second side, a first lens E1, a polarizer LP, a reflective polarizer RP, and a quarter-wave plate QWP. The second element group includes, from the first side to the second side, a second lens E2, a partially reflective element BS, and a display. It should be noted that in this embodiment, the first side end of the first lens barrel Pa extends toward the optical axis so that the first side surface of the first lens rests on the first lens barrel Pa. Therefore, the first lens E1, the polarizer LP, the reflective polarizer RP, and the quarter-wave plate QWP are assembled from the second side of the first lens barrel Pa; simultaneously, the second side end of the second lens barrel Pb extends toward the optical axis so that the second side surface of the second lens rests on the second lens barrel Pb. Therefore, the second lens E2 and the partially reflective element BS are assembled from the first side of the second lens barrel Pb.

[0090] In this embodiment, the first lens has positive 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 has positive power, the first side surface of the second lens is convex, and the second side surface of the second lens is convex. The visual system further comprises an aperture STO located between the first side and the first element group. The first side surface of the polarizer is at least partially bonded to the second side surface of the first lens, the second side surface of the polarizer is bonded to the first side surface of the reflective polarizing element, the second side surface of the reflective polarizing element is bonded to the first side surface of the quarter-wave plate, and the first side surface of the partially reflective element is at least partially bonded to the second side surface of the second lens.

[0091] In this embodiment, light from the image surface IMG sequentially passes through the second lens E2 and the quarter-wave plate QWP before reaching the reflective polarizer RP. After being reflected by the reflective polarizer RP, the light again sequentially passes through the quarter-wave plate QWP and the second lens E2 before reaching the partially reflective element BS on the second side surface of the second lens. The light is then reflected by the partially reflective element BS again before passing through the second lens E2, the quarter-wave plate QWP, the reflective polarizer RP, the polarizer LP, and the first lens E1 before exiting.

[0092] Table 2 shows the basic structural parameters of the visual system of Example 1, where the units for the radius of curvature, thickness / distance, and effective focal length are all in millimeters. In Table 2, light from the image surface IMG propagates from surface number 16 toward surface number 0. Refraction / reflection refers to the refraction or reflection of the light by the surface represented by that surface number. The surfaces represented by surface numbers 16 to 0 are, in order: the image surface, the second side surface of the second lens, the first side surface of the second lens, the second side surface of the quarter-wave plate, the first side surface of the quarter-wave plate (the second side surface of the reflective polarizer), the second side surface of the quarter-wave plate, the first side surface of the second lens, the second side surface of the second lens (the first side surface of the partially reflective element), the first side surface of the second lens, the second side surface of the quarter-wave plate, the first side surface of the quarter-wave plate (the second side surface of the reflective polarizer), the first side surface of the reflective polarizer (the second side surface of the polarizer), the first side surface of the polarizer, the second side surface of the first lens, the first side surface of the first lens, the aperture surface, and the virtual image surface.

[0093] Table 2

[0094]

[0095] In Example 1, the first side surface of the first lens E1, the first side surface of the second lens E2, and the second side surface of the second lens E2 are aspherical surfaces. The surface shape of the aspherical surfaces can be defined by, but is not limited to, the following aspherical surface formula:

[0096] Formula (1);

[0097] Where x is the distance vector from the vertex of the aspheric surface at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c = 1 / R, i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 2 above; k is the conic coefficient; Ai is the correction coefficient for the i-th order of the aspheric surface. Table 3 below lists the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for the aspheric surface in Example 1.

[0098] Table 3

[0099]

[0100] In this embodiment, the second element group is moved to change the diopter of the visual system, which can be achieved by Figure 1 The first state (+2D state) shown is converted to Figure 2 The second state (-5D state) is shown. As shown in Table 4, some structural parameters of the visual system have changed. D1 represents the virtual image distance of the visual system of this embodiment. D2, D3, and D4 represent the distances on the optical axis from the second side surface of the quarter-wave plate to the first side surface of the second lens. Positive values ​​of D1, D2, D3, and D4 indicate a direction from the first side to the second side, while negative values ​​indicate a direction from the second side to the first side. The units of D1, D2, D3, and D4 are all millimeters (mm).

[0101] Table 4

[0102]

[0103] Figure 4 and Figure 5 The MTF curves of the visual system of Example 1 in the first state (+2D state) and the second state (-5D state) are shown. The MTF values ​​under the light of each field of view are all above 0.8, showing good imaging quality.

[0104] Example 2

[0105] like Figure 6 and Figure 7 As shown, the visual system of embodiment 2 of the present application is described. Figure 6 and Figure 7 The first state and the second state of the visual system of Example 2 are described respectively. The visual system of this embodiment has the same optical parameters as that of Example 1, but different structural parameters. Please refer to the relevant description of Example 1 and will not be repeated here.

[0106] Example 3

[0107] like Figure 8 and Figure 9 As shown, the visual system of embodiment 3 of the present application is described. Figure 8 and Figure 9 The first state and the second state of the visual system of Example 3 are described respectively. The visual system of this embodiment has the same optical parameters as that of Example 1, but different structural parameters. Please refer to the relevant description of Example 1 and will not be repeated here.

[0108] Example 4

[0109] like Figure 10 and Figure 11 As shown, the structures of the visual system of embodiment 4 of the present application in the first state and the second state are described respectively.

[0110] like Figure 10 and Figure 11 As shown, the first element group rests on the first lens barrel Pa, and at least a portion of the second element group rests on the second lens barrel Pb. The first element group includes, from the first side to the second side, a first lens E1, a polarizer LP, a reflective polarizer RP, and a quarter-wave plate QWP. The second element group includes, from the first side to the second side, a second lens E2, a partially reflective element BS, and a display. It should be noted that in this embodiment, the first side end of the first lens barrel Pa extends toward the optical axis so that the first side surface of the first lens rests on the first lens barrel Pa. Therefore, the first lens E1, the polarizer LP, the reflective polarizer RP, and the quarter-wave plate QWP are assembled from the second side of the first lens barrel Pa; simultaneously, the second side end of the second lens barrel Pb extends toward the optical axis so that the second side surface of the second lens rests on the second lens barrel Pb. Therefore, the second lens E2 and the partially reflective element BS are assembled from the first side of the second lens barrel Pb.

[0111] In this embodiment, the first lens has positive 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 has positive power, the first side surface of the second lens is convex, and the second side surface of the second lens is convex. The visual system further comprises an aperture STO located between the first side and the first element group. The first side surface of the polarizer is at least partially bonded to the second side surface of the first lens, the second side surface of the polarizer is bonded to the first side surface of the reflective polarizing element, the second side surface of the reflective polarizing element is bonded to the first side surface of the quarter-wave plate, and the first side surface of the partially reflective element is at least partially bonded to the second side surface of the second lens.

[0112] In this embodiment, light from the image surface IMG sequentially passes through the second lens E2 and the quarter-wave plate QWP before reaching the reflective polarizer RP. After being reflected by the reflective polarizer RP, the light again sequentially passes through the quarter-wave plate QWP and the second lens E2 before reaching the partially reflective element BS on the second side surface of the second lens. The light is then reflected by the partially reflective element BS again before passing through the second lens E2, the quarter-wave plate QWP, the reflective polarizer RP, the polarizer LP, and the first lens E1 before exiting.

[0113] Table 5 shows the basic structural parameters of the visual system of Example 4, where the units for the radius of curvature, thickness / distance, and effective focal length are all in millimeters. In Table 5, light from the image surface IMG propagates from surface number 16 to the side of surface number 0. Refraction / reflection refers to the refraction or reflection of the light by the surface represented by that surface number. The surfaces represented by surface numbers 16 to 0 are, in order: the image surface, the second side surface of the second lens, the first side surface of the second lens, the second side surface of the quarter-wave plate, the first side surface of the quarter-wave plate (the second side surface of the reflective polarizer), the second side surface of the quarter-wave plate, the first side surface of the second lens, the second side surface of the second lens (the first side surface of the partially reflective element), the first side surface of the second lens, the second side surface of the quarter-wave plate, the first side surface of the quarter-wave plate (the second side surface of the reflective polarizer), the first side surface of the reflective polarizer (the second side surface of the polarizer), the first side surface of the polarizer, the second side surface of the first lens, the first side surface of the first lens, the aperture surface, and the virtual image surface.

[0114] Table 5

[0115]

[0116] In Example 4, the first side surface of the first lens E1, the first side surface of the second lens E2, and the second side surface of the second lens E2 are aspherical surfaces. The surface shape of the aspherical surfaces can be defined using, but not limited to, formula (1) in Example 1. Table 6 below lists the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 of the aspherical surfaces that can be used in Example 4.

[0117] Table 6

[0118]

[0119] In this embodiment, the second element group is moved to change the diopter of the visual system, which can be achieved by Figure 1 The first state (+2D state) shown is converted to Figure 2The second state (-5D state) is shown. As shown in Table 7, some structural parameters of the visual system have changed. D1 represents the virtual image distance of the visual system of this embodiment. D2, D3, and D4 represent the distances on the optical axis from the second side surface of the quarter-wave plate to the first side surface of the second lens. Positive values ​​of D1, D2, D3, and D4 indicate a direction from the first side to the second side, while negative values ​​indicate a direction from the second side to the first side. The units of D1, D2, D3, and D4 are all millimeters (mm).

[0120] Table 7

[0121]

[0122] Figure 12 and Figure 13 The MTF curves of the visual system of Example 4 in the first state (+2D state) and the second state (-5D state) are shown. The MTF values ​​under the light of each field of view are all above 0.8, showing good imaging quality.

[0123] Example 5

[0124] like Figure 14 and Figure 15 As shown, the visual system of embodiment 5 of the present application is described. Figure 14 and Figure 15 The first state and the second state of the visual system of Example 5 are described respectively. The visual system of this embodiment has the same optical parameters as that of Example 4, but different structural parameters. Please refer to the relevant description of Example 4 and will not be repeated here.

[0125] Example 6

[0126] like Figure 16 and Figure 17 As shown, the visual system of embodiment 6 of the present application is described. Figure 16 and Figure 17 The first state and the second state of the visual system of Example 6 are described respectively. The visual system of this embodiment has the same optical parameters as that of Example 4, but different structural parameters. Please refer to the relevant description of Example 4 and will not be repeated here.

[0127] Example 7

[0128] like Figure 18 and Figure 19 As shown, the structures of the visual system of embodiment 7 of the present application in the first state and the second state are described respectively.

[0129] like Figure 18 and Figure 19As shown, the first element group rests on the first lens barrel Pa, and at least a portion of the second element group rests on the second lens barrel Pb. The first element group includes, from the first side to the second side, a first lens E1, a polarizer LP, a reflective polarizer RP, and a quarter-wave plate QWP. The second element group includes, from the first side to the second side, a second lens E2, a partially reflective element BS, and a display. It should be noted that in this embodiment, the first side end of the first lens barrel Pa extends toward the optical axis so that the first side surface of the first lens rests on the first lens barrel Pa. Therefore, the first lens E1, the polarizer LP, the reflective polarizer RP, and the quarter-wave plate QWP are assembled from the second side of the first lens barrel Pa; simultaneously, the second side end of the second lens barrel Pb extends toward the optical axis so that the second side surface of the second lens rests on the second lens barrel Pb. Therefore, the second lens E2 and the partially reflective element BS are assembled from the first side of the second lens barrel Pb.

[0130] In this embodiment, the first lens has positive 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 has positive power, the first side surface of the second lens is convex, and the second side surface of the second lens is convex. The visual system further comprises an aperture STO located between the first side and the first element group. The first side surface of the polarizer is at least partially bonded to the second side surface of the first lens, the second side surface of the polarizer is bonded to the first side surface of the reflective polarizing element, the second side surface of the reflective polarizing element is bonded to the first side surface of the quarter-wave plate, and the first side surface of the partially reflective element is at least partially bonded to the second side surface of the second lens.

[0131] In this embodiment, light from the image surface IMG sequentially passes through the second lens E2 and the quarter-wave plate QWP before reaching the reflective polarizer RP. After being reflected by the reflective polarizer RP, the light again sequentially passes through the quarter-wave plate QWP and the second lens E2 before reaching the partially reflective element BS on the second side surface of the second lens. The light is then reflected by the partially reflective element BS again before passing through the second lens E2, the quarter-wave plate QWP, the reflective polarizer RP, the polarizer LP, and the first lens E1 before exiting.

[0132] Table 8 shows the basic structural parameters of the visual system of Example 7, where the units for the radius of curvature, thickness / distance, and effective focal length are all in millimeters (mm). In Table 8, light from the image surface IMG propagates from surface number 16 to the side of surface number 0. Refraction / reflection refers to the refraction or reflection of the light by the surface represented by that surface number. The surfaces represented by surface numbers 16 to 0 are, in order: the image surface, the second side surface of the second lens, the first side surface of the second lens, the second side surface of the quarter-wave plate, the first side surface of the quarter-wave plate (the second side surface of the reflective polarizer), the second side surface of the quarter-wave plate, the first side surface of the second lens, the second side surface of the second lens (the first side surface of the partially reflective element), the first side surface of the second lens, the second side surface of the quarter-wave plate, the first side surface of the quarter-wave plate (the second side surface of the reflective polarizer), the first side surface of the reflective polarizer (the second side surface of the polarizer), the first side surface of the polarizer, the second side surface of the first lens, the first side surface of the first lens, the aperture surface, and the virtual image surface.

[0133] Table 8

[0134]

[0135] In Example 7, the first side surface of the first lens E1, the first side surface of the second lens E2, and the second side surface of the second lens E2 are aspherical surfaces. The surface shape of the aspherical surfaces can be defined using, but not limited to, formula (1) in Example 1. Table 9 below lists the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 of the aspherical surfaces that can be used in Example 7.

[0136] Table 9

[0137]

[0138] In this embodiment, the second element group is moved to change the diopter of the visual system, which can be achieved by Figure 1 The first state (+2D state) shown is converted to Figure 2 The second state (-5D state) is shown. As shown in Table 10, some structural parameters of the visual system have changed. D1 represents the virtual image distance of the visual system of this embodiment, and D2, D3, and D4 represent the distances on the optical axis from the second side surface of the quarter-wave plate to the first side surface of the second lens. Positive values ​​for D1, D2, D3, and D4 indicate a direction from the first side to the second side, while negative values ​​indicate a direction from the second side to the first side. The units of D1, D2, D3, and D4 are all millimeters (mm).

[0139] Table 10

[0140]

[0141] Figure 20 and Figure 21 The MTF curves of the visual system of Example 7 in the first state (+2D state) and the second state (-5D state) are shown. The MTF values ​​under the light of each field of view are all above 0.8, showing good imaging quality.

[0142] Example 8

[0143] like Figure 22 and Figure 23 As shown, the visual system of embodiment 8 of the present application is described. Figure 22 and Figure 23 The first state and the second state of the visual system of Example 8 are described respectively. The visual system of this embodiment has the same optical parameters as that of Example 7, but different structural parameters. Please refer to the relevant description of Example 7 and will not be repeated here.

[0144] Example 9

[0145] like Figure 24 and Figure 25 As shown, the visual system of embodiment 9 of the present application is described. Figure 24 and Figure 25 The first state and the second state of the visual system of Example 9 are described respectively. The visual system of this embodiment has the same optical parameters as that of Example 7, but different structural parameters. Please refer to the relevant description of Example 7 and will not be repeated here.

[0146] In summary, embodiments 1 to 9 of the visual system respectively satisfy the relationship shown in Table 11. The conditional expressions for the first state and the second state corresponding to each embodiment of the visual system have the same values.

[0147] Table 11

[0148]

[0149] Table 12 shows the effective focal lengths and some structural parameters of each lens and element group of the visual system of Examples 1 to 9, in mm.

[0150] Table 12

[0151]

[0152] Table 13 gives some structural parameters of the visual systems of Examples 1 to 9, in mm.

[0153] Table 13

[0154]

[0155] Obviously, the embodiments described above are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0156] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, tasks, devices, components and / or combinations thereof.

[0157] It should be noted that the terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0158] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A visual system, characterized in that: The visual system includes: An optical element group, the optical element group comprising a first element group and a second element group, wherein the first element group comprises, in order from the first side to the second side, a first lens, a polarizer, a reflective polarizer, and a quarter-wave plate, along the direction of the optical axis of the visual system, the first element group comprises, in order from the first side to the second side, a first lens, a polarizer, a reflective polarizer, and a quarter-wave plate, the first lens having positive optical power, a first side surface of the first lens being a convex surface, and a second side surface of the first lens being a flat surface; and the second element group comprises, in order from the first side to the second side, a second lens, a partially reflective element, and a display, the second lens having positive optical power, a first side surface of the second lens being a convex surface, and a second side surface of the second lens being a convex surface; a lens barrel assembly, the lens barrel assembly comprising a first lens barrel and a second lens barrel, the first element assembly resting on the first lens barrel, and at least a portion of the second element assembly resting on the second lens barrel; wherein the second element group is capable of moving along the direction of the optical axis to approach or move away from the first element group; The change Δf of the effective focal length of the visual system from the +2D state to the -5D state, the outer diameter Dbs of the first side surface of the second lens barrel, and the outer diameter Dbm of the second side surface of the second lens barrel satisfy the following: 0.33≤Δf / (Dbs-Dbm)≤1.46; The maximum thickness Lb from the first side surface of the second lens barrel to the second side surface of the second 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: 1.04≤Lb / ΔL≤2.

08.

2. The visual system according to claim 1, characterized in that: The maximum thickness La from the first side surface of the first lens barrel to the second side surface of the first lens barrel, the center thickness CT1 of the first lens on the optical axis, the center thickness CTL of the polarizer on the optical axis, the center thickness CTR of the reflective polarizing element on the optical axis, and the center thickness CTQ of the quarter-wave plate on the optical axis satisfy the following: 1.07≤La / (CT1+CTL+CTR+CTQ)≤2.

33.

3. The visual system according to claim 1, wherein: A curvature radius R1 of the first side surface of the first lens and an inner diameter das of the first side surface of the first lens barrel satisfy the following relationship: 2.22≤R1 / das≤2.

87.

4. The visual system according to claim 1, wherein: The combined focal length fz of the first lens, the polarizer, the reflective polarizing element, and the quarter-wave plate and the outer diameter Dam of the second side surface of the first lens barrel satisfy the following relationship: 3.06≤fz / Dam≤4.

27.

5. The visual system according to claim 1, wherein: A curvature radius R3 of the first side surface of the second lens, a curvature radius R4 of the second side surface of the second lens, and an inner diameter dbs of the first side surface of the second barrel satisfy: 0.69≤(R3+R4) / dbs≤3.

04.

6. The visual system according to claim 1, wherein: The inner diameter dbm of the second side surface of the second 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: 10.13≤dbm / ΔL≤10.

94.

7. The visual system according to claim 1, wherein: An inner diameter dbs of the first side surface of the second barrel, an inner diameter dbm of the second side surface of the second barrel, and a center thickness CT2 of the second lens on the optical axis satisfy: 0.81≤(dbs−dbm) / CT2≤1.

42.

8. The visual system according to claim 1, wherein: The effective focal length f1 of the first lens, the refractive index N1 of the first lens, and the inner diameter dam of the second side surface of the first lens barrel satisfy the following: 2.18≤(f1 / N1) / dam≤2.

90.

9. The visual system according to claim 1, wherein: When the visual system moves from the +2D state to the -5D state, the distance ΔL moved by the second element group along the direction of the optical axis, the outer diameter Dam of the second side surface of the first lens barrel and the outer diameter Das of the first side surface of the first lens barrel satisfy the following relationship: 5.16mm≤ΔL×(Dam / Das)≤5.80mm.

10. The visual system according to claim 1, wherein: The maximum thickness La from the first side surface of the first lens barrel to the second side surface of the first lens barrel and the change Δf of the effective focal length of the visual system from the +2D state to the -5D state satisfy the following: 1.68≤La / Δf≤4.

34.

11. The visual system according to claim 1, wherein: The effective focal length f2 of the second lens and the outer diameter Dbs of the first side surface of the second lens barrel satisfy the following relationship: 2.63≤f2 / Dbs≤3.

23.

12. The visual system according to claim 1, wherein: A maximum thickness Lb from the first side surface of the second barrel to the second side surface of the second barrel and a refractive index N2 of the second lens satisfy the following: 3.34 mm ≤ Lb / N2 ≤ 6.17 mm.

13. The visual system according to claim 1, wherein: The maximum thickness La from the first side surface of the first lens barrel to the second side surface of the first lens barrel, the maximum thickness Lb from the first side surface of the second lens barrel to the second side surface of the second lens barrel, the center thickness CT1 of the first lens on the optical axis, and the center thickness CT2 of the second lens on the optical axis satisfy the following: 1.07≤(La+Lb) / (CT1+CT2)≤1.

95.

14. The visual system according to claim 1, wherein: The change Δf of the effective focal length of the visual system from the +2D state to the -5D state, the inner diameter dbs of the first side surface of the second lens barrel and the inner diameter dam of the second side surface of the first lens barrel satisfy the following relationship: 1.00≤Δf / (dbs-dam)≤6.29.

Images