Visual system

Abstract

The invention provides a visual system, which comprises an optical element group and a lens cone group, and is characterized in that the first element group comprises a first lens, a polarizing film, a reflective polarizing element and a quarter-wave plate, and the second element group comprises a second lens, a partial reflection element and a display; the lens cone group comprises a first lens cone and a second lens cone, the first element group leans against the first lens cone, and at least one part of the second element group leans against the second lens cone; the variable quantity delta f of the effective focal length of the visual system moving 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 meet the condition that delta f / (Dbs-Dbm) is greater than or equal to 0.33 and less than or equal to 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 Delta L by which 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 relation: 1.04 < = Lb / Delta L < = 2.08. The problem that in the prior art, a visual system is poor in assembling stability is solved.

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 popularization of the concept of "metaverse", augmented reality (AR) and virtual reality (VR) technologies have ushered in new development opportunities. In order to provide a more realistic and immersive visual experience, VR devices need to adopt advanced optical solutions to meet the requirements of high resolution and wearing comfort. When assembling lenses in a limited space, the visual system in the existing technology is limited by the sensitivity of the lens surface, and the shape of the lens surface varies greatly, resulting in poor assembly stability of the visual system and greatly reduced assembly yield. Therefore, how to control the shape of the lens barrel and the space allocation in the visual system, and take into account the miniaturization and assembly stability of the visual system, is a very important 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 comprises 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 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 comprises 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; a lens barrel group, the lens barrel group comprises a first lens barrel and a second lens barrel, the first lens barrel group comprises a second lens barrel, a reflective polarizing 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; A component group rests on the first lens barrel, and at least a part of the second component group rests on the second lens barrel; wherein the second component group can move along the direction of the optical axis to approach or move away from the first component group; the change Δf of the effective focal length when the visual system 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 moved by the second component group 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. The visual system includes: an optical element group, which 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 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 first lens has a 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 sequentially includes a second lens, a partially reflective element, and a display from the first side to the second side. The second lens has a 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, which includes a first lens barrel and a second lens barrel. The first element group is supported on the first lens barrel, and at least a part of the second element group is supported 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 amount Δf of the effective focal length when the visual system 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: 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.

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

[0007] Further, 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.

[0008] Further, 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: 3.06 ≤ fz / Dam ≤ 4.27.

[0009] Further, 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 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 central 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 barrel satisfy: 2.18 ≤ (f1 / N1) / dam ≤ 2.90.

[0013] Furthermore, 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 barrel, and the outer diameter Das of the first side surface of the first barrel satisfy: 5.16 mm ≤ ΔL×(Dam / Das) ≤ 5.80 mm.

[0014] Furthermore, the maximum thickness La from the first side surface to the second side surface of the first barrel and the change in effective focal length Δf of the visual system when moving from the +2D state to the -5D state satisfy: 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 barrel satisfy: 2.63 ≤ f2 / Dbs ≤ 3.23.

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

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

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

[0019] Applying the technical solution of the present invention, 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 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 first lens has a 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 sequentially includes a second lens, a partial reflection element, and a display from the first side to the second side. The second lens has a 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 is supported on the first lens barrel, and at least a part of the second element group is supported on the second lens barrel. Among them, 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 amount Δf of the effective focal length of the visual system moving 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 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: 1.04 ≤ Lb / ΔL ≤ 2.08.

[0020] In this application, by reasonably configuring the visual system, on the basis of meeting the miniaturization of the second lens barrel, the assembly and support stability of the first lens and the second lens will become poor. By controlling Δf / (Dbs - Dbm) and Lb / ΔL within a certain range, the surface shape of the second lens barrel and the thickness along the optical axis direction are restricted. While ensuring sufficient space for the light path to turn back during the large-range adjustment of the diopter, the second lens can be stably supported on the second lens barrel, and the first lens can be stably supported on the first lens barrel, reducing the risk of assembly deformation of the first lens and the second lens and improving the assembly stability of the first lens and the second lens. Description of the Drawings

[0021] The specification drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0022] Figure 1 It shows a partial parameter schematic diagram of the visual system of any optional embodiment of the present invention;

[0023] Figure 2 It shows a structural schematic diagram of the visual system of Embodiment 1 of the present invention in the first state;

[0024] Figure 3Shows the structural schematic diagram of the visual system according to the first embodiment of the present invention in the second state;

[0025] Figure 4 Shows the MTF curve graph of the visual system according to the first embodiment of the present invention in the first state;

[0026] Figure 5 Shows the MTF curve graph of the visual system according to the first embodiment of the present invention in the second state;

[0027] Figure 6 Shows the structural schematic diagram of the visual system according to the second embodiment of the present invention in the first state;

[0028] Figure 7 Shows the structural schematic diagram of the visual system according to the second embodiment of the present invention in the second state;

[0029] Figure 8 Shows the structural schematic diagram of the visual system according to the third embodiment of the present invention in the first state;

[0030] Figure 9 Shows the structural schematic diagram of the visual system according to the third embodiment of the present invention in the second state;

[0031] Figure 10 Shows the structural schematic diagram of the visual system according to the fourth embodiment of the present invention in the first state;

[0032] Figure 11 Shows the structural schematic diagram of the visual system according to the fourth embodiment of the present invention in the second state;

[0033] Figure 12 Shows the MTF curve graph of the visual system according to the fourth embodiment of the present invention in the first state;

[0034] Figure 13 Shows the MTF curve graph of the visual system according to the fourth embodiment of the present invention in the second state.

[0035] Figure 14 Shows the structural schematic diagram of the visual system according to the fifth embodiment of the present invention in the first state;

[0036] Figure 15 Shows the structural schematic diagram of the visual system according to the fifth embodiment of the present invention in the second state;

[0037] Figure 16 Shows the structural schematic diagram of the visual system according to the sixth embodiment of the present invention in the first state;

[0038] Figure 17 Shows the structural schematic diagram of the visual system according to the sixth embodiment of the present invention in the second state;

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

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

[0041] Figure 20 Shows the MTF curve diagram of the visual system according to the seventh embodiment of the present invention in the first state;

[0042] Figure 21 Shows the MTF curve diagram of the visual system according to the seventh embodiment of the present invention in the second state;

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

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

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

[0046] Figure 25 Shows a schematic structural diagram of the visual system according to the ninth embodiment of the present invention in the second state.

[0047] Among them, the above-mentioned drawings include the following reference numerals:

[0048] Pa, the first lens barrel; Pb, the second lens barrel; E1, the first lens; LP, the polarizer; RP, the reflective polarizing element; QWP, the quarter-wave plate; E2, the second lens; BS, the partial reflection element; IMG, the image plane. Detailed implementation manners

[0049] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0050] It should be pointed out that unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0051] In the present invention, unless otherwise stated, the orientation words such as "upper, lower, top, bottom" are usually in the direction shown in the drawings, or in the vertical, perpendicular or gravitational direction of the component itself; similarly, for the convenience of understanding and description, "inside, outside" refer to the inside and outside relative to the contour of each component itself, but the above orientation words do not limit the present invention.

[0052] It should be noted that in this specification, the expressions such as first, second, third, etc. are only used to distinguish one feature from another, and do not represent any limitation on the features. Therefore, without departing from the teachings of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0053] In the drawings, for the sake of clarity, the thickness, size and shape of the lens have been slightly exaggerated. Specifically, the spherical or aspherical shapes shown in the drawings are shown by way of example. That is, the spherical or aspherical shapes are not limited to the spherical or aspherical shapes shown in the drawings. The drawings are for illustrative purposes only and are not drawn to an exact scale.

[0054] In this document, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface 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 position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The judgment of the surface shape in the paraxial region can be based on the judgment method of those with ordinary knowledge in the field, and the positive or negative of the R value (R refers to the radius of curvature in the paraxial region, usually the R value on the lens database (lens data) in optical software) is used to judge the convexity and concavity. For the eye side surface, when the R value is positive, it is judged to be convex, and when the R value is negative, it is judged to be concave; for the display side surface, when the R value is positive, it is judged to be concave, and when the R value is negative, it is judged to be convex.

[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] As Figures 1 to 25As shown in the figure, 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 optical axis direction of the visual system, the first element group 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 first lens has a 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 sequentially includes a second lens, a partial reflection element, and a display from the first side to the second side. The second lens has a 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 is supported on the first lens barrel, and at least a part of the second element group is supported on the second lens barrel. Among them, the second element group can move along the optical axis direction to approach or move away from the first element group. The change amount Δf of the effective focal length when the visual system 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: 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 direction when the visual system moves from the +2D state to the -5D state satisfy: 1.04 ≤ Lb / ΔL ≤ 2.08.

[0058] In this application, by reasonably configuring the visual system, on the basis of meeting the miniaturization of the second lens barrel, the assembly and support stability of the first lens and the second lens will become poor. By controlling Δf / (Dbs - Dbm) and Lb / ΔL within a certain range, the surface shape of the second lens barrel and the thickness along the optical axis direction are restricted. While ensuring sufficient space for the light path to fold back during the large-range adjustment of the diopter, the second lens can be stably supported on the second lens barrel, and the first lens can be stably supported on the first lens barrel, reducing the risk of assembly deformation of the first lens and the second lens and improving the assembly stability of the first lens and the second lens.

[0059] Table 1 below gives a comparison of the assembly surface type change sensitivities of the visual systems of Comparative Example 1, Comparative Example 2, and an optional solution 1 of this application. The displacements of the center points 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 are measured respectively, and the assembly surface type change amounts are summarized to intuitively judge the assembly deformation degrees of the visual systems of different solutions.

[0060] Table 1

[0061]

[0062] As can be obtained from Table 1 above, for the visual system of Comparative Example 1, under the conditions of Δf / (Dbs-Dbm)=1.8 and Lb / ΔL=2.4, large displacements occurred at the center points and edge points of each surface of the first lens and the second lens, and the degree of assembly change of the surface shape was relatively large. For the visual system of Comparative Example 2, under the conditions of Δf / (Dbs-Dbm)=0.1 and Lb / ΔL=0.6, large displacements occurred at the center points and edge points of each surface of the first lens and the second lens, and the degree of assembly change of the surface shape was relatively large. However, for 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, the displacements of the center point and edge point of the lens surface were well controlled, and the change in the surface shape after assembly was very small, which could effectively ensure the assembly stability and the reliability of the visual system.

[0063] In this embodiment, the following relationship is satisfied among the maximum thickness La from the first side surface to the second side surface of the first barrel, the central thickness CT1 of the first lens on the optical axis, the central thickness CTL of the polarizing plate on the optical axis, the central thickness CTR of the reflective polarizing element on the optical axis, and the central thickness CTQ of the quarter-wave plate on the optical axis: 1.07≤La / (CT1+CTL+CTR+CTQ)≤2.33. By restricting La / (CT1+CTL+CTR+CTQ) within a reasonable range, on the one hand, the length of the first barrel can be controlled, and the effective focal length of the overall visual system can be made smaller, meeting the miniaturization design of the head-mounted device. On the other hand, the wall thickness of the first barrel can be indirectly controlled, which can ensure the feasibility of processing and forming the first barrel.

[0064] In this embodiment, the following relationship is satisfied between 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 barrel: 2.22≤R1 / das≤2.87. By restricting R1 / das within a reasonable range, on the one hand, the optical power of the first lens is controlled, which is beneficial to correcting the aberration of the visual system. On the other hand, the shape of the first lens is restricted, which is beneficial to reducing the sensitivity of the first lens, thereby improving the assembly yield of the visual system.

[0065] In this embodiment, the following relationship is satisfied between the combined focal length fz of the first lens, the polarizing plate, the reflective polarizing element, and the quarter-wave plate and the outer diameter Dam of the second side surface of the first barrel: 3.06≤fz / Dam≤4.27. By restricting fz / Dam within a reasonable range, on the one hand, the image height of the visual system is controlled, and the screen size is restricted. On the other hand, the volume of the first barrel is controlled, which is beneficial to the miniaturization design of the first barrel and further beneficial to the visual system adapting to the miniaturized head-mounted device.

[0066] In this embodiment, the following relationship is satisfied among 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 barrel: 0.69 ≤ (R3 + R4) / dbs ≤ 3.04. By restricting (R3 + R4) / dbs within a reasonable range, on the one hand, the shape of the second lens is constrained, which is beneficial to reducing the sensitivity of the second lens, thereby improving the assembly yield of the visual system. On the other hand, the optical power of the second lens is controlled, which is beneficial to correcting the aberration of the visual system.

[0067] In this embodiment, the following relationship is satisfied between the inner diameter dbm of the second side surface of the second 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: 10.13 ≤ dbm / ΔL ≤ 10.94. By restricting dbm / ΔL within a reasonable range, on the premise of ensuring the performance of the visual system, it is beneficial to reduce the size of the head-mounted device, while reducing the aberration and chromatic aberration of imaging and improving the picture clarity of the outer field of view.

[0068] In this embodiment, the following relationship is satisfied among 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 central thickness CT2 of the second lens on the optical axis: 0.81 ≤ (dbs - dbm) / CT2 ≤ 1.42. By restricting (dbs - dbm) / CT2 within a reasonable range, on the one hand, the thickness ratio of the second lens can be controlled, which is beneficial to the forming and gluing of the second lens. On the other hand, the assembly stability of the second lens is improved, thereby improving the assembly yield of the visual system.

[0069] In this embodiment, the following relationship is satisfied among 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 barrel: 2.18 ≤ (f1 / N1) / dam ≤ 2.90. By restricting (f1 / N1) / dam within a reasonable range, on the one hand, optical materials with conventional properties can be more reasonably selected, which is beneficial to correcting the chromatic aberration of the visual system. On the other hand, the optical powers of the first lens and the second lens can be controlled. Combining with the air gap between the two lenses, the focal length of the visual system can be controlled, thereby restricting the field of view angle of the visual system and meeting the use requirements of the wide angle of the head-mounted device.

[0070] In this embodiment, when the visual system moves from the +2D state to the -5D state, the distance ΔL that the second element group moves 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: 5.16 mm ≤ ΔL × (Dam / Das) ≤ 5.80 mm. By restricting ΔL × (Dam / Das) within a reasonable range, the optical power of the visual system is effectively distributed. On the premise of meeting the effective focal length of the visual system, the aberration of the visual system is corrected, and the imaging quality is improved.

[0071] In this embodiment, the maximum thickness La from the first side surface to the second side surface of the first lens barrel and the change amount Δf of the effective focal length of the visual system when moving from the +2D state to the -5D state satisfy: 1.68 ≤ La / Δf ≤ 4.34. By restricting La / Δf within a reasonable range, on the one hand, the thickness of the first lens barrel is constrained, ensuring the formability of the first lens barrel, and on the other hand, the length of the visual system as a whole along the optical axis is indirectly constrained, which is beneficial to the thinning and lightening of the 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: 2.63 ≤ f2 / Dbs ≤ 3.23. By restricting f2 / Dbs within a reasonable range, on the one hand, the assembly stability can be improved, and at the same time, the volume of the second lens barrel is constrained, which is beneficial to the miniaturization design of the head-mounted device; on the other hand, the effective focal length and the maximum field of view angle of the second lens can be controlled, thereby controlling the image height of the visual system and restricting the screen size.

[0073] In this embodiment, the maximum thickness Lb from the first side surface to the second side surface of the second lens barrel and the refractive index N2 of the second lens satisfy: 3.34 mm ≤ Lb / N2 ≤ 6.17 mm. By restricting Lb / N2 within a reasonable range, on the one hand, the volume size of the second lens barrel is constrained, and on the other hand, optical materials with conventional properties can be more reasonably selected, which is beneficial to correcting the chromatic aberration of the visual system.

[0074] In this embodiment, the maximum thickness La from the first side surface to the second side surface of the first lens barrel, the maximum thickness Lb from the first side surface to the second side surface of the second lens barrel, the central thickness CT1 of the first lens on the optical axis, and the central thickness CT2 of the second lens on the optical axis satisfy: 1.07 ≤ (La + Lb) / (CT1 + CT2) ≤ 1.95. By restricting (La + Lb) / (CT1 + CT2) within a reasonable range, on the one hand, the volume size of the entire lens barrel group can be constrained, which is beneficial to the thinning and lightening of the head-mounted device, and on the other hand, the effective focal length and the maximum field of view angle of the visual system are controlled, improving the imaging quality while meeting the wide-angle imaging.

[0075] In this embodiment, the change amount Δf of the effective focal length of the visual system moving from the +2D state to the -5D state, the inner diameter dbs of the first side surface of the second barrel, and the inner diameter dam of the second side surface of the first barrel satisfy: 1.00 ≤ Δf / (dbs - dam) ≤ 6.29. By restricting Δf / (dbs - dam) within a reasonable range, on the one hand, the shapes of the first barrel and the second barrel are constrained, and the wall thicknesses of the first barrel and the second barrel are controlled, which is beneficial to the miniaturized design of the visual system. On the other hand, the optical power of the visual system is effectively allocated. On the premise of satisfying the effective focal length of the visual system, the system aberration is corrected and the imaging quality is improved.

[0076] Second Embodiment

[0077] As Figures 1 to 25 shown, the visual system includes an optical element group and a barrel group. The optical element group includes a first element group and a second element group. Along the optical axis direction of the visual system, the first element group 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 first lens has a 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 flat surface. The second element group sequentially includes a second lens, a partially reflective element, and a display from the first side to the second side. The second lens has a 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 barrel group includes a first barrel and a second barrel. The first element group abuts against the first barrel, and at least a part of the second element group abuts against the second barrel. Among them, the second element group can move along the optical axis direction to approach or move away from the first element group. The change amount Δf of the effective focal length of the visual system moving from the +2D state to the -5D state, the outer diameter Dbs of the first side surface of the second barrel, and the outer diameter Dbm of the second side surface of the second barrel satisfy: 0.33 ≤ Δf / (Dbs - Dbm) ≤ 1.46. 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 barrel satisfy: 2.22 ≤ R1 / das ≤ 2.87.

[0078] In this application, by reasonably configuring the visual system, on the basis of meeting the miniaturization of the second lens barrel, the assembly and bearing stability of the first lens and the second lens will become poor. By controlling Δf / (Dbs - Dbm) and R1 / das within a certain range, the surface shapes of the first lens barrel and the second lens barrel and the thickness along the optical axis direction are restricted. At the same time, the shapes of the first lens and the second lens are indirectly restricted, which can reduce the sensitivity of the lens, ensure that the second lens can stably bear on the second lens barrel, the first lens can stably bear on the first lens barrel, reduce the risk of assembly deformation of the first lens and the second lens, improve the assembly stability 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 also be controlled to correct the aberration of the visual system.

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

[0080] In this application, at least one of the mirror surfaces of the first lens and the second lens is an aspherical mirror surface. The characteristics of an aspherical lens are that the curvature changes continuously from the center of the lens to the periphery of the lens. Different from a spherical lens with a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has better curvature radius characteristics and has the advantages of improving distortion aberration and astigmatism aberration. After using an aspherical lens, it is possible to eliminate the aberration that appears during imaging as much as possible, thereby improving the imaging quality.

[0081] However, those skilled in the art should understand that without departing from the technical solutions claimed in this application, the number of lenses constituting the visual system can be changed to obtain the various results and advantages described in this specification. For example, although two lenses are described as an example in the embodiment, the visual system is not limited to including two lenses. If necessary, the visual system may also include other numbers of lenses.

[0082] Figure 1 Parameters such as das and Dbm are marked to clearly and intuitively understand the meaning of the parameters. For the convenience of showing the structure of the visual system and the specific surface shape, these parameters will no longer be shown in the subsequent description of specific examples in the drawings.

[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 radii, central thicknesses, and high-order image coefficients of the first lens and the second lens are the same in these two states, but parameters such as the spacing distance between the first element group and the second element group, and the lens barrel are different.

[0084] It should be noted that the movement of the second element group of the visual system closer to the first element group along the optical axis brings about a change in diopter. The diopter of the visual system is +2D in the first state and -5D in the second state. Among them, in the first state, it means that the visual system is suitable for users with a hyperopia degree of 200, and in the second state, it means that the visual system is suitable for users with a myopia degree of 500. The visual system also has other states other than the first state and the second state, and the diopter of the visual system in other states can be between +2D and -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, with reference to the accompanying drawings, embodiments of the specific surface shape and parameters of the visual system applicable to the above embodiments.

[0087] Embodiment 1

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

[0089] As Figure 2 and Figure 3 shown, the first element group is supported on the first lens barrel Pa, at least a part of the second element group is supported on the second lens barrel Pb. The first element group sequentially includes a first lens E1, a polarizer LP, a reflective polarizing element RP, and a quarter-wave plate QWP from the first side to the second side. The second element group sequentially includes a second lens E2, a partial reflection element BS, and a display from the first side to the second side. It should be noted that in this embodiment, the first side end of the first lens barrel Pa extends in the direction of the optical axis so that the first side surface of the first lens is supported on the first lens barrel Pa. Therefore, the first lens E1, the polarizer LP, the reflective polarizing element RP, and the quarter-wave plate QWP are assembled from the second side of the first lens barrel Pa; at the same time, the second side end of the second lens barrel Pb extends in the direction of the optical axis so that the second side surface of the second lens is supported on the second lens barrel Pb. Therefore, the second lens E2 and the partial reflection element BS are assembled from the first side of the second lens barrel Pb.

[0090] In this embodiment, the first lens has a positive optical power. The first side of the first lens is convex, and the second side of the first lens is flat. The second lens has a positive optical power. The first side of the second lens is convex, and the second side of the second lens is convex. Among them, the visual system further has a stop STO located between the first side and the first element group. The first side of the polarizer is at least partially attached to the second side of the first lens. The second side of the polarizer is attached to the first side of the reflective polarizing element. The second side of the reflective polarizing element is attached to the first side of the quarter-wave plate. The first side of the partial reflection element is at least partially attached to the second side of the second lens.

[0091] In this embodiment, the light rays from the image plane IMG sequentially pass through the second lens E2 and the quarter-wave plate QWP and then reach the reflective polarizing element RP. After being reflected by the reflective polarizing element RP, the light rays pass through the quarter-wave plate QWP and the second lens E2 again and then reach the partial reflection element BS on the second side of the second lens. The light rays are reflected by the partial reflection element BS and then pass through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, the polarizer LP, and the first lens E1 and exit.

[0092] Table 2 shows the basic structural parameter table of the visual system in the first embodiment. Among them, the units of the radius of curvature, thickness / distance, and effective focal length are all millimeters (mm). In Table 2, the light rays from the image plane IMG propagate from the surface number 16 to the side of the surface number 0, and the refraction / reflection is the refraction or reflection effect of the light rays by the surface represented by this surface number. Among them, the surfaces represented by the surface numbers 16 to 0 are the image plane, the second side of the second lens, the first side of the second lens, the second side of the quarter-wave plate, the first side of the quarter-wave plate (the second side of the reflective polarizing element), the second side of the quarter-wave plate, the first side of the second lens, the second side of the second lens (the first side of the partial reflection element), the first side of the second lens, the second side of the quarter-wave plate, the first side of the quarter-wave plate (the second side of the reflective polarizing element), the first side of the reflective polarizing element (the second side of the polarizer), the first side of the polarizer, the second side of the first lens, the first side of the first lens, the stop surface, and the virtual image surface.

[0093] Table 2

[0094]

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

[0096] Formula (1);

[0097] Wherein, when x is the distance sagitta from the vertex of the aspheric surface at the position with height h along the optical axis of the aspheric surface; c is the paraxial curvature of the aspheric surface, c = 1 / R, that is, 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 of the i-th order of the aspheric surface. Table 3 below gives the higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for the aspheric surface in Embodiment 1.

[0098] Table 3

[0099]

[0100] In this embodiment, by moving the second element group to change the diopter of the visual system, it can be realized to switch from Figure 1 the first state (+2D state) shown in Figure 2 to the second state (-5D state) shown in

[0101] Table 4

[0102]

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

[0104] Embodiment 2

[0105] As Figure 6 and Figure 7 shown, it describes the visual system of Embodiment 2 of the present application. Figure 6 and Figure 7 describe the first state and the second state of the visual system of Embodiment 2 respectively. The visual system of this embodiment has the same optical parameters as those of Embodiment 1, but different structural parameters. For the relevant descriptions in Embodiment 1, reference can be made, and details will not be repeated here.

[0106] Embodiment 3

[0107] As Figure 8 andFigure 9 As shown, it describes the visual system of Embodiment 3 of the present application. Figure 8 and Figure 9 respectively describe the first state and the second state of the visual system of Embodiment 3. The visual system of this embodiment has the same optical parameters as those of Embodiment 1, but different structural parameters. For the relevant descriptions in Embodiment 1, reference can be made, and details will not be elaborated here.

[0108] Embodiment 4

[0109] As Figure 10 and Figure 11 shown, they respectively describe the structures of the visual system of Embodiment 4 of the present application in the first state and the second state.

[0110] As Figure 10 and Figure 11 shown, the first element group abuts against the first lens barrel Pa, at least a part of the second element group abuts against the second lens barrel Pb. The first element group sequentially includes a first lens E1, a polarizer LP, a reflective polarizing element RP, and a quarter-wave plate QWP from the first side to the second side. The second element group sequentially includes a second lens E2, a partially reflective element BS, and a display from the first side to the second side. It should be noted that in this embodiment, the first side end of the first lens barrel Pa extends towards the optical axis direction so that the first side surface of the first lens abuts against the first lens barrel Pa. Therefore, the first lens E1, the polarizer LP, the reflective polarizing element RP, and the quarter-wave plate QWP are assembled from the second side of the first lens barrel Pa; at the same time, the second side end of the second lens barrel Pb extends towards the optical axis direction so that the second side surface of the second lens abuts against 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 a 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 has a positive optical power. The first side surface of the second lens is convex, and the second side surface of the second lens is convex. Among them, the visual system also has a stop STO located between the first side and the first element group. The first side surface of the polarizer is at least partially attached to the second side surface of the first lens. The second side surface of the polarizer is attached to the first side surface of the reflective polarizing element. The second side surface of the reflective polarizing element is attached to the first side surface of the quarter-wave plate. The first side surface of the partially reflective element is at least partially attached to the second side surface of the second lens.

[0112] In this embodiment, the light from the image plane IMG sequentially passes through the second lens E2 and the quarter-wave plate QWP and then reaches the reflective polarizing element RP. After being reflected by the reflective polarizing element RP, the light passes through the quarter-wave plate QWP and the second lens E2 again and then reaches the partial reflection element BS on the second side of the second lens. It is reflected by the partial reflection element BS, passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, the polarizing plate LP, and the first lens E1 again and exits.

[0113] Table 5 shows the basic structural parameter table of the visual system in the fourth embodiment. Among them, the units of the radius of curvature, thickness / distance, and effective focal length are all millimeters (mm). In Table 5, the light from the image plane IMG propagates from the surface number 16 to the side of the surface number 0, and the refraction / reflection means that the light is refracted or reflected by the surface represented by this surface number. Among them, the surfaces represented by the surface numbers 16 to 0 are the image plane, the second side of the second lens, the first side of the second lens, the second side of the quarter-wave plate, the first side of the quarter-wave plate (the second side of the reflective polarizing element), the second side of the quarter-wave plate, the first side of the second lens, the second side of the second lens (the first side of the partial reflection element), the first side of the second lens, the second side of the quarter-wave plate, the first side of the quarter-wave plate (the second side of the reflective polarizing element), the first side of the reflective polarizing element (the second side of the polarizing plate), the first side of the polarizing plate, the second side of the first lens, the first side of the first lens, the aperture plane, and the virtual image plane.

[0114] Table 5

[0115]

[0116] In the fourth embodiment, the first side of the first lens E1, the first side of the second lens E2, and the second side of the second lens E2 are aspherical surfaces, and the surface shape of the aspherical surface can be defined by, but not limited to, the formula (1) in the first embodiment. The following Table 6 gives the higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for the aspherical surface in the fourth embodiment.

[0117] Table 6

[0118]

[0119] In this embodiment, by moving the second element group to change the diopter of the visual system, it can be realized that Figure 1 the first state (+2D state) shown in Figure 2The second state shown (-5D state). As shown in Table 7, some structural parameters of the visual system change. Among them, D1 represents the value of the virtual image distance of the visual system in this embodiment, and D2, D3, and D4 represent the distances from the second side of the quarter-wave plate to the first side of the second lens on the optical axis. When D1, D2, D3, and D4 are positive, the direction is from the first side to the second side, and 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).

[0120] Table 7

[0121]

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

[0123] Embodiment Five

[0124] As Figure 14 and Figure 15 shown, it describes the visual system of the fifth embodiment of the present application. Figure 14 and Figure 15 respectively describe the first state and the second state of the visual system of the fifth embodiment. The visual system of this embodiment has the same optical parameters as that of the fourth embodiment, but different structural parameters. For the relevant descriptions, reference can be made to those in the fourth embodiment, which will not be elaborated here.

[0125] Embodiment Six

[0126] As Figure 16 and Figure 17 shown, it describes the visual system of the sixth embodiment of the present application. Figure 16 and Figure 17 respectively describe the first state and the second state of the visual system of the sixth embodiment. The visual system of this embodiment has the same optical parameters as that of the fourth embodiment, but different structural parameters. For the relevant descriptions, reference can be made to those in the fourth embodiment, which will not be elaborated here.

[0127] Embodiment Seven

[0128] As Figure 18 and Figure 19 shown, it respectively describes the structures of the visual system of the seventh embodiment of the present application in the first state and the second state.

[0129] As Figure 18 and Figure 19As shown, the first element group abuts against the first lens barrel Pa, and at least a part of the second element group abuts against the second lens barrel Pb. The first element group sequentially includes a first lens E1, a polarizer LP, a reflective polarizing element RP, and a quarter-wave plate QWP from the first side to the second side. The second element group sequentially includes a second lens E2, a partial reflection element BS, and a display from the first side to the second side. It should be noted that in this embodiment, the first-side end of the first lens barrel Pa extends in the direction of the optical axis so that the first side surface of the first lens abuts against the first lens barrel Pa. Therefore, the first lens E1, the polarizer LP, the reflective polarizing element RP, and the quarter-wave plate QWP are assembled from the second side of the first lens barrel Pa. At the same time, the second-side end of the second lens barrel Pb extends in the direction of the optical axis so that the second side surface of the second lens abuts against the second lens barrel Pb. Therefore, the second lens E2 and the partial reflection element BS are assembled from the first side of the second lens barrel Pb.

[0130] In this embodiment, the first lens has a 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 has a positive optical power. The first side surface of the second lens is convex, and the second side surface of the second lens is convex. Among them, the visual system further has a diaphragm STO located between the first side and the first element group. The first side surface of the polarizer is at least partially attached to the second side surface of the first lens. The second side surface of the polarizer is attached to the first side surface of the reflective polarizing element. The second side surface of the reflective polarizing element is attached to the first side surface of the quarter-wave plate. The first side surface of the partial reflection element is at least partially attached to the second side surface of the second lens.

[0131] In this embodiment, the light rays from the image plane IMG sequentially pass through the second lens E2 and the quarter-wave plate QWP and then reach the reflective polarizing element RP. After being reflected by the reflective polarizing element RP, the light rays pass through the quarter-wave plate QWP and the second lens E2 again and then reach the partial reflection element BS on the second side surface of the second lens. After being reflected by the partial reflection element BS, the light rays exit 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 again.

[0132] Table 8 shows the basic structural parameter table of the visual system in the seventh embodiment. Among them, the units of the radius of curvature, thickness / distance, and effective focal length are all millimeters (mm). In Table 8, the light from the image plane IMG propagates from the surface number 16 to the side of surface number 0, and refraction / reflection means that the light is refracted or reflected by the surface represented by this surface number. Among them, the surfaces represented by surface numbers 16 to 0 are the image plane, the second side of the second lens, the first side of the second lens, the second side of the quarter-wave plate, the first side of the quarter-wave plate (the second side of the reflective polarizing element), the second side of the quarter-wave plate, the first side of the second lens, the second side of the second lens (the first side of the partial reflection element), the first side of the second lens, the second side of the quarter-wave plate, the first side of the quarter-wave plate (the second side of the reflective polarizing element), the first side of the reflective polarizing element (the second side of the polarizer), the first side of the polarizer, the second side of the first lens, the first side of the first lens, the aperture plane, and the virtual image plane.

[0133] Table 8

[0134]

[0135] In the seventh embodiment, the first side of the first lens E1, the first side of the second lens E2, and the second side of the second lens E2 are aspherical surfaces, and the surface profiles of the aspherical surfaces can be defined by, but not limited to, formula (1) in the first embodiment. The following Table 9 gives the higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for the aspherical surfaces in the seventh embodiment.

[0136] Table 9

[0137]

[0138] In this embodiment, by moving the second element group to change the diopter of the visual system, it can be realized that the visual system is switched from Figure 1 the first state (+2D state) shown to Figure 2 the second state (-5D state) shown. As shown in Table 10, some structural parameters of the visual system change. Among them, D1 represents the value of the virtual image distance of the visual system in this embodiment, and D2, D3, and D4 represent the distances on the optical axis from the second side of the quarter-wave plate to the first side of the second lens. When D1, D2, D3, and D4 are positive, the direction is from the first side to the second side, and 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).

[0139] Table 10

[0140]

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

[0142] Example 8

[0143] As Figure 22 and Figure 23 shown, it describes the visual system of Example 8 of the present application. Figure 22 and Figure 23 describe the first state and the second state of the visual system of Example 8 respectively. The visual system of this example has the same optical parameters as those of Example 7, but different structural parameters. For the relevant descriptions, reference can be made to those in Example 7 and will not be elaborated here.

[0144] Example 9

[0145] As Figure 24 and Figure 25 shown, it describes the visual system of Example 9 of the present application. Figure 24 and Figure 25 describe the first state and the second state of the visual system of Example 9 respectively. The visual system of this example has the same optical parameters as those of Example 7, but different structural parameters. For the relevant descriptions, reference can be made to those in Example 7 and will not be elaborated here.

[0146] In summary, Examples 1 to 9 of the visual system respectively satisfy the relationships shown in Table 11. Among them, the conditional value takings of the first state and the second state corresponding to each example of the visual system are the same.

[0147] Table 11

[0148]

[0149] Table 12 gives the effective focal lengths and some structural parameters of each lens and each element group of the visual systems of Examples 1 to 9, with the unit of mm.

[0150] Table 12

[0151]

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

[0153] Table 13

[0154]

[0155] Obviously, the embodiments described above are only some of the embodiments of the present invention, not all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope 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 forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0157] It should be noted that the terms "first", "second", etc. in the description and claims of the present application and the above drawings 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 under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0158] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A visual system, characterized in that: The visual system comprises: 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 order 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 order 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; A lens barrel group, the lens barrel group comprising 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 is capable of moving along the direction of the optical axis to approach or move away from the first element group; The change amount 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, characterized in that: 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: 2.22≤R1 / das≤2.

87.

4. The visual system according to claim 1, characterized in that: The combined focal length fz of the first lens, the polarizing plate, 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, characterized in that: 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 lens barrel satisfy: 0.69≤(R3+R4) / dbs≤3.

04.

6. The visual system according to claim 1, characterized in that: 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 direction of 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, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: A maximum thickness La from the first side surface of the first lens barrel to the second side surface of the first lens barrel and a change Δf in 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, characterized in that: 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: 2.63≤f2 / Dbs≤3.

23.

12. The visual system according to claim 1, characterized in that: 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: 3.34 mm≤Lb / N2≤6.17 mm.

13. 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 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, characterized in that: 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.

Images