Visual system

Abstract

The present application discloses a visual system, which comprises a first and a second lens barrel arranged in sequence from a first side to a second side along an optical axis, and a first and a second lens group respectively supported by the two lens barrels; the first lens group comprises a first lens, a reflective polarizing element and a quarter wave plate in sequence, and the second lens group comprises a second lens, a partial reflecting element and a third lens in sequence; the optical powers of the first to third lenses are respectively positive, positive and negative, and the surface types are respectively convex-flat, convex-convex and concave-convex; the second and the third lenses are glued together; the second lens group can be moved along the optical axis to approach or move away from a display located on the second side, so that the system can be switched between the first and the second states; the combined focal length f23 of the second and the third lenses and the inner diameter dbs of the first side end face of the second lens barrel satisfy 3.93≤f23 / dbs≤4.30, and the maximum heights La and Lb of the first and second lens barrels along the optical axis respectively and the distance ΔL of the second lens group moving along the optical axis during the process of the system switching from the first state to the second state satisfy 4.55<(La+Lb) / ΔL<5.05.

Description

Technical Field

[0001] The present application relates to the field of optical elements, and more specifically, to a visual system. Background Art

[0002] Since the concept of "metaverse" was proposed, AR / VR (Augmented Reality / Virtual Reality) technology has ushered in a second opportunity for development. As the entrance to human-computer interaction, VR imaging lenses play an important role. On the one hand, the imaging quality of VR imaging lenses needs to meet the resolution requirements of the human eye; on the other hand, the early aspherical or Fresnel lenses were relatively long, and the center of gravity was forward when used, resulting in a poor user experience. The reentrant optical solution can greatly compress the length of the lens body by folding the optical path, and accordingly significantly reduce the weight of the device, thereby improving the consumer experience.

[0003] However, although the existing reentrant optical design based on folded optical path performs well in shortening the lens length, there is still room for improvement in optical performance. For example, the side walls of the lens barrel and other structural parts in the system are prone to reflective stray light, which interferes with imaging and affects image quality and clarity, and needs to be improved urgently. In addition, among people using VR, everyone's vision is different. There are many users with myopia or hyperopia, and the degree of myopia or hyperopia in different people's eyes is also different. If a fixed focal length reentrant module is used, the image quality seen will vary, and the experience effect obtained will vary greatly. Therefore, it is necessary to design and develop a visual system with adjustable diopter so that users with different vision can see the image clearly without wearing glasses, thereby improving the VR visual experience. Summary of the invention

[0004] The present application provides a visual system, which may include a lens barrel group and a lens group. Among them, the lens barrel group includes a first lens barrel and a second lens barrel arranged in sequence from the first side to the second side along the optical axis; the lens group includes a first lens group and a second lens group arranged in sequence from the first side to the second side along the optical axis; and the first lens group abuts against the first lens barrel, and the second lens group abuts against the second lens barrel. The first lens group further includes a first lens, a reflective polarizing element, and a quarter-wave plate arranged in sequence from the first side to the second side along the optical axis, and the second lens group further includes a second lens, a partially reflective element, and a third lens arranged in sequence from the first side to the second side along the optical axis. Among them, the first lens has a positive optical power, its first side is convex, and its second side is flat; the second lens has a positive optical power, its first side is convex, and its second side is convex; the third lens has a negative optical power, its first side is concave, and its second side is convex; and the second lens and the third lens are cemented together. The second lens group is configured to be able to move along the optical axis to approach or move away from a display located on the second side, and to switch the visual system between a first state and a second state. The visual system can satisfy the conditions of 3.93≤f23 / dbs≤4.30 and 4.55<(La+Lb) / ΔL<5.05, where f23 is the combined focal length of the second lens and the third lens, dbs is the inner diameter of the first side end face of the second lens barrel, La is the maximum distance on the optical axis from the first side end face of the first lens barrel to the second side end face of the first lens barrel, Lb is the maximum distance on the optical axis from the first side end face of the second lens barrel to the second side end face of the second lens barrel, and ΔL is the distance that the second lens group moves along the optical axis during the process of the visual system switching from the first state to the second state.

[0005] In one embodiment, the inner diameter das of the first side end face of the first lens barrel and the entrance pupil diameter EPD of the visual system can satisfy: 4.35<das / EPD<4.65.

[0006] In one embodiment, the combined focal length fz of the first lens, the reflective polarizing element, and the quarter-wave plate and the maximum distance La on the optical axis from the first side end face of the first lens barrel to the second side end face of the first lens barrel can satisfy: 27.49≤fz / La≤34.83.

[0007] In one embodiment, the inner diameter dam of the second side end face of the first lens barrel and the central thickness CT1 of the first lens 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 can satisfy: 8.35<dam / (CT1+CTR+CTQ)<10.75.

[0008] In one embodiment, the outer diameter Dbs of the first side end face of the second lens barrel, the inner diameter dbm of the second side end face of the second lens barrel, and the change amount Δf of the effective focal length of the visual system when switching from the first state to the second state may satisfy: 7.36 ≤ (Dbs - dbm) / Δf ≤ 8.81.

[0009] In one embodiment, the effective focal length f1 of the first lens and the outer diameter Das of the first side end face of the first lens barrel may satisfy: 2.55 < f1 / Das < 3.35.

[0010] In one embodiment, the outer diameter Dbs of the first side end face of the second lens barrel, the inner diameter dam of the second side end face of the first lens barrel, and the distance ΔL that the second lens group moves along the optical axis during the process of the visual system switching from the first state to the second state may satisfy: 2.15 < (Dbs - dam) / ΔL < 4.05.

[0011] In one embodiment, the effective focal length f2 of the second lens, the effective focal length f3 of the third lens, and the maximum distance Lb on the optical axis from the first side end face to the second side end face of the second lens barrel may satisfy: 3.7 mm < |f2 / f3| × Lb < 4.1 mm.

[0012] In one embodiment, the radius of curvature R6 of the second side face of the third lens and the outer diameter Dbm of the second side end face of the second lens barrel may satisfy: -11.01 ≤ R6 / Dbm ≤ -7.41.

[0013] In one embodiment, the radius of curvature R1 of the first side face of the first lens and the outer diameter Dam of the second side end face of the first lens barrel may satisfy: 1.35 ≤ R1 / Dam ≤ 1.70.

[0014] In one embodiment, the outer diameter Das of the first side end face of the first lens barrel, the inner diameter das of the first side end face of the first lens barrel, and the maximum distance La on the optical axis from the first side end face to the second side end face of the first lens barrel may satisfy: 1.28 ≤ (Das - das) / La ≤ 1.90.

[0015] In one embodiment, the maximum distance Lb on the optical axis from the first side end face to the second side end face of the second lens barrel and the change amount Δf of the effective focal length of the visual system when switching from the first state to the second state may satisfy: 9.75 < Lb / Δf < 10.45.

[0016] In one embodiment, the outer diameter Dbm of the second side end face of the second lens barrel, the inner diameter dbm of the second side end face of the second lens barrel, and the central thickness CT3 of the third lens on the optical axis may satisfy: 1.0 < (Dbm - dbm) / CT3 < 1.6.

[0017] In one embodiment, the outer diameter Dbs of the first side end face of the second barrel and the inner diameter das of the first side end face of the first barrel may satisfy: 1.25 < Dbs / das < 1.45.

[0018] The visual system disclosed in this application includes a barrel group and a lens group. The barrel group includes a first barrel and a second barrel arranged in sequence from the first side to the second side along the optical axis. The lens group includes a first lens group and a second lens group arranged in sequence from the first side to the second side along the optical axis. Among them, the first lens group abuts against the first barrel, and the second lens group abuts against the second barrel. The first lens group further includes a first lens, a reflective polarizing element, and a quarter-wave plate arranged in sequence from the first side to the second side along the optical axis. The second lens group further includes a second lens, a partial reflection element, and a third lens arranged in sequence from the first side to the second side along the optical axis. Among them, the first lens has a positive optical power, its first side is convex, and its second side is flat; the second lens has a positive optical power, its first side is convex, and its second side is convex; the third lens has a negative optical power, its first side is concave, and its second side is convex; and the second lens and the third lens are cemented lenses that are cemented to each other. The second lens group in the visual system is configured to be able to move along the optical axis to approach or move away from the display located on the second side, and to switch the visual system between a first state and a second state. Through the above configuration of the visual system, and by controlling the combined focal length f23 of the second lens and the third lens and the inner diameter dbs of the first side end face of the second barrel to satisfy the conditional formula 3.93 ≤ f23 / dbs ≤ 4.30, the maximum distance La on the optical axis from the first side end face of the first barrel to the second side end face of the first barrel, the maximum distance Lb on the optical axis from the first side end face of the second barrel to the second side end face of the second barrel, and the distance ΔL that the second lens group moves along the optical axis during the process of the visual system switching from the first state to the second state satisfy the conditional formula 4.55 < (La + Lb) / ΔL < 5.05, it is possible to enable the visual system to adjust the diopter between the +2D state and the -5D state, and at the same time, it can help reduce the stray light interference at the side wall of the second barrel, ensuring that users can obtain clear images under different visual needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In combination with the drawings, through the following detailed description of non-limiting embodiments, other features, purposes, and advantages of this application will become more obvious. In the drawings:

[0020] Figure 1 The structure and partial parameter schematic diagram of the visual system according to an exemplary embodiment of this application are shown;

[0021] Figure 2The left and right figures therein respectively show schematic structural diagrams of the visual system according to Embodiment 1 of the present application when in the first state (+2D state) and the second state (-5D state);

[0022] Figure 3 The left and right figures therein respectively show schematic structural diagrams of the visual system according to Embodiment 2 of the present application when in the first state (+2D state) and the second state (-5D state);

[0023] Figure 4 The left and right figures therein respectively show schematic structural diagrams of the visual system according to Embodiment 3 of the present application when in the first state (+2D state) and the second state (-5D state);

[0024] Figure 5 Shows the MTF (Modulation Transfer Function) graph of the visual system according to Embodiment 1, Embodiment 2, and Embodiment 3 of the present application when in the first state (+2D state);

[0025] Figure 6 Shows the MTF graph of the visual system according to Embodiment 1, Embodiment 2, and Embodiment 3 of the present application when in the second state (-5D state);

[0026] Figure 7 The left and right figures therein respectively show schematic structural diagrams of the visual system according to Embodiment 4 of the present application when in the first state (+2D state) and the second state (-5D state);

[0027] Figure 8 The left and right figures therein respectively show schematic structural diagrams of the visual system according to Embodiment 5 of the present application when in the first state (+2D state) and the second state (-5D state);

[0028] Figure 9 The left and right figures therein respectively show schematic structural diagrams of the visual system according to Embodiment 6 of the present application when in the first state (+2D state) and the second state (-5D state);

[0029] Figure 10 Shows the MTF graph of the visual system according to Embodiment 4, Embodiment 5, and Embodiment 6 of the present application when in the first state (+2D state);

[0030] Figure 11 Shows the MTF graph of the visual system according to Embodiment 4, Embodiment 5, and Embodiment 6 of the present application when in the second state (-5D state);

[0031] Figure 12The left and right figures therein respectively show schematic structural diagrams of the visual system according to Embodiment 7 of the present application when in the first state (+2D state) and the second state (-5D state);

[0032] Figure 13 The left and right figures therein respectively show schematic structural diagrams of the visual system according to Embodiment 8 of the present application when in the first state (+2D state) and the second state (-5D state);

[0033] Figure 14 The left and right figures therein respectively show schematic structural diagrams of the visual system according to Embodiment 9 of the present application when in the first state (+2D state) and the second state (-5D state);

[0034] Figure 15 Shows the MTF diagram of the visual system according to Embodiment 7, Embodiment 8 and Embodiment 9 of the present application when in the first state (+2D state);

[0035] Figure 16 Shows the MTF diagram of the visual system according to Embodiment 7, Embodiment 8 and Embodiment 9 of the present application when in the second state (-5D state);

[0036] Figure 17 Shows the stray light situation diagram of the exemplary visual system according to the present application when satisfying the conditional expressions f23 / dbs = 3.5 and (La + Lb) / ΔL = 4.1;

[0037] Figure 18 Shows the stray light situation diagram of the exemplary visual system according to the present application when satisfying the conditional expressions f23 / dbs = 4.7 and (La + Lb) / ΔL = 5.5;

[0038] Figure 19 Shows the stray light situation diagram of the exemplary visual system according to the present application when satisfying the conditional expressions f23 / dbs = 4.17 and (La + Lb) / ΔL = 4.84. Detailed implementation manners

[0039] To better understand the present application, more detailed descriptions of various aspects of the present application will be made with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the exemplary embodiments of the present application and do not limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0040] 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.

[0041] In the drawings, for ease of illustration, the thickness, dimensions, 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 only examples and are not drawn to an exact scale.

[0042] In this context, 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.

[0043] It should also be understood that the terms "comprises", "comprising", "has", "including" and / or "containing", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when an expression such as "at least one of..." appears after a list of listed features, it modifies the entire list of listed features rather than individual elements in the list. In addition, when describing the embodiments of the present application, the use of "may" means "one or more embodiments of the present application". And the term "exemplary" is intended to refer to an example or illustration.

[0044] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formalized sense unless expressly so defined herein.

[0045] 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 following embodiments only express several implementation manners of the present application, and their descriptions are relatively specific and detailed, but should not be construed as a limitation on the patent scope of the present application. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can be made, and these all belong to the protection scope of the present application. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0046] The features, principles, and other aspects of the present application will be described in detail below.

[0047] According to an exemplary embodiment of the present application, the visual system may include a lens barrel group and a lens group. The lens barrel group may include a first lens barrel and a second lens barrel; the lens group may include a first lens group and a second lens group. The first lens barrel and the second lens barrel may be arranged in sequence along the optical axis from the first side to the second side; the first lens group and the second lens group may be arranged in sequence along the optical axis from the first side to the second side.

[0048] In an exemplary embodiment, the first lens group may be abutted against or assembled to the first lens barrel; the second lens group may be abutted against or assembled to the second lens barrel.

[0049] In an exemplary embodiment, the first lens group may include a first lens, a reflective polarizing element, and a quarter-wave plate. Exemplarily, the first lens, the reflective polarizing element, and the quarter-wave plate may be arranged in sequence along the optical axis from the first side to the second side.

[0050] In an exemplary embodiment, the reflective polarizing element may be disposed on or attached to the second side surface of the first lens; the quarter-wave plate may be disposed on or attached to the second side surface of the reflective polarizing element. Exemplarily, the first side surface of the reflective polarizing element may be at least partially adhered to the second side surface of the first lens; the first side surface of the quarter-wave plate may be at least partially adhered to the second side surface of the reflective polarizing element.

[0051] In an exemplary embodiment, the second lens group may include a second lens, a partial reflection element, and a third lens. Exemplarily, the second lens, the partial reflection element, and the third lens may be arranged in sequence along the optical axis from the first side to the second side.

[0052] In an exemplary embodiment, the second lens and the third lens may be mutually cemented to form a cemented lens. Specifically, the second lens, the partial reflection element, and the third lens may be mutually cemented to form a cemented lens.

[0053] In an exemplary embodiment, the first lens may have a positive optical power, its first side surface may be convex, and its second side surface may be flat.

[0054] In an exemplary embodiment, the second lens may have a positive optical power, its first side surface may be convex, and its second side surface may be convex.

[0055] In an exemplary embodiment, the third lens may have a negative optical power, its first side surface may be concave, and its second side surface may be convex.

[0056] By reasonably setting the structure of the visual system, the folding back of the optical path can be achieved, effectively shortening the body length of the visual system, reducing the volume and weight of the visual system, and realizing the lightweight of the visual system. The setting of the cemented lens provides a high-quality lens material for the system, which has the advantages of light weight, good light transmittance, wear resistance, etc., and is more suitable for the lens manufacturing of VR devices, and can improve the quality and adaptability of the lens.

[0057] Understandably, in the direction along the optical axis, the surfaces of each element or structure in the visual system that are close to the first side and far from the second side can be the first side surface of the element or structure, and the surfaces of each element that are close to the second side and far from the first side can be the second side surface of the element or structure. The first side surface and the second side surface of the element or structure can be perpendicular to the optical axis, for example.

[0058] In an exemplary embodiment, the first side can be the human eye side, for example, and the second side can be the display side, for example. The visual system can be used in a variety of VR devices or apparatuses, for example.

[0059] In an exemplary embodiment, the distance of the first lens group (or the first lens group and the first lens barrel) from the display or image plane on the second side of the visual system along the optical axis can be fixed. The second lens group (or the second lens group and the second lens barrel) can be configured to be movable along the optical axis to approach or move away from the display or image plane located on the second side of the visual system, and to switch the visual system between a first state and a second state. Specifically, when the second lens group (or the second lens group and the second lens barrel) moves to the position closest to the display or image plane, at this time, the distance between the second lens group and the first lens group along the optical axis is the largest, and the visual system can be in the +2D state, that is, the first state; when the second lens group (or the second lens group and the second lens barrel) moves to the position farthest from the display or image plane, at this time, the distance between the second lens group and the first lens group along the optical axis is the smallest, and the visual system can be in the -5D state, that is, the second state.

[0060] Exemplarily, when the visual system is in the first state, the diopter of the visual system is +2D, and it can be applicable to users with a diopter of +2D, for example; when the visual system is in the second state, the diopter of the visual system is -5D, and it can be applicable to users with a diopter of -5D, for example. Among them, when the sign of the diopter is negative, it can indicate that the user is a myopic user; when the sign of the diopter is positive, it can indicate that the user is a hyperopic user; the specific value of the diopter can represent the refractive power of the user. For example, a diopter of +1D can indicate that the user's hyperopia degree is about 100 degrees, and a diopter of -1D can indicate that the user's myopia degree is about 100 degrees.

[0061] It should be understood that, in addition to the first state and the second state, the visual system according to the embodiments of the present application may also have other states, for example, between -5D and +2D. The visual system according to the embodiments of the present application can achieve continuous zoom within the range of -5D to +2D, which can meet the needs of users with different visual acuities, enabling users to enjoy the VR experience without wearing glasses.

[0062] In an exemplary embodiment, the visual system of the present application may include at least one aperture stop. The aperture stop can restrict the light path and control the light intensity. The aperture stop can be set at an appropriate position of the visual system as needed. For example, the aperture stop can be located between the first side (such as the human eye side) and the first lens.

[0063] In an exemplary embodiment, the virtual image distances (VIDs) of the visual system in the first state and the second state are different. The virtual image distance can be, for example, the distance from the virtual image formed by the image light from the second side at a predetermined position to the aperture stop on the optical axis. Wherein, VID = 1000 / diopter.

[0064] In an exemplary embodiment, the visual system of the present application can satisfy the conditional formula 3.93 ≤ f23 / dbs ≤ 4.30, where f23 is the combined focal length of the second lens and the third lens, and dbs is the inner diameter of the first side end face of the second lens barrel. It can be understood that the first side end face of the lens barrel can be the end face or surface of the lens barrel closest to the first side and perpendicular or approximately perpendicular to the optical axis; the second side end face of the lens barrel can be the end face or surface of the lens barrel closest to the second side and perpendicular or approximately perpendicular to the optical axis.

[0065] In an exemplary embodiment, the visual system of the present application can satisfy the conditional formula 4.55 < (La + Lb) / ΔL < 5.05, where La is the maximum distance on the optical axis from the first side end face of the first lens barrel to the second side end face of the first lens barrel, Lb is the maximum distance on the optical axis from the first side end face of the second lens barrel to the second side end face of the second lens barrel, and ΔL is the distance that the second lens group moves along the optical axis during the process of the visual system switching from the +2D state to the -5D state.

[0066] The visual system provided according to an exemplary embodiment of the present application includes a lens barrel group and a lens group. The lens barrel group includes a first lens barrel and a second lens barrel arranged in sequence from the first side to the second side along the optical axis. The lens group includes a first lens group and a second lens group arranged in sequence from the first side to the second side along the optical axis. Among them, the first lens group abuts against the first lens barrel, and the second lens group abuts against the second lens barrel. The first lens group further includes a first lens, a reflective polarizing element, and a quarter-wave plate arranged in sequence from the first side to the second side along the optical axis. The second lens group further includes a second lens, a partially reflective element, and a third lens arranged in sequence from the first side to the second side along the optical axis. Among them, the first lens has a positive optical power, its first side is convex, and its second side is flat; the second lens has a positive optical power, its first side is convex, and its second side is convex; the third lens has a negative optical power, its first side is concave, and its second side is convex; and the second lens and the third lens are cemented lenses that are cemented to each other. The second lens group in the visual system is configured to be movable along the optical axis to approach or move away from a display located on the second side, and to switch the visual system between a first state and a second state. By configuring the visual system as described above, and controlling the combined focal length f23 of the second lens and the third lens and the inner diameter dbs of the first side end face of the second lens barrel to satisfy the conditional expression 3.93 ≤ f23 / dbs ≤ 4.30, the maximum distance La on the optical axis from the first side end face of the first lens barrel to the second side end face of the first lens barrel, the maximum distance Lb on the optical axis from the first side end face of the second lens barrel to the second side end face of the second lens barrel, and the distance ΔL that the second lens group moves along the optical axis during the process of the visual system switching from the first state to the second state satisfy the conditional expression 4.55 < (La + Lb) / ΔL < 5.05, it is possible to enable the visual system to adjust the diopter between the +2D state and the -5D state, and at the same time, it is also possible to help reduce the stray light interference at the side wall of the second lens barrel, ensuring that users can obtain clear images under different visual requirements.

[0067] In the exemplary embodiment, the lens group and the lens barrel group of the visual system are configured as described above. At the same time, by setting the above two conditional expressions f23 / dbs and (La + Lb) / ΔL to satisfy different numerical ranges respectively, the following three different visual system solutions can be formed:

[0068] In the visual system 1 of the first solution, the above two conditional expressions f23 / dbs and (La + Lb) / ΔL satisfy f23 / dbs = 3.5 and (La + Lb) / ΔL = 4.1 respectively. It can be seen that the numerical values of the two conditional expressions are both small, and they are respectively smaller than the lower limit values of the ranges defined by the conditional expressions 3.93 ≤ f23 / dbs ≤ 4.30 and 4.55 < (La + Lb) / ΔL < 5.05. The stray light diagram of the imaging effect of the visual system 1 is as Figure 17 shown, from Figure 17It can be seen that there is more stray light in the system of this solution. For example, reflected stray light is likely to be generated on the side wall of the second lens barrel, etc., and the intensity of the stray light is relatively high, reaching 1.45E-3, which has a great impact on the imaging effect.

[0069] In the visual system 2 of the second solution, the above two conditional expressions f23 / dbs and (La + Lb) / ΔL respectively satisfy f23 / dbs = 4.7 and (La + Lb) / ΔL = 5.5. It can be seen that the values of the two conditional expressions are both relatively large, and they are respectively greater than the upper limit values of the ranges defined by the conditional expressions 3.93 ≤ f23 / dbs ≤ 4.30 and 4.55 < (La + Lb) / ΔL < 5.05. The stray light diagram of the imaging effect of this visual system 2 is as Figure 18 shown, from Figure 18 It can be seen that there is also more stray light in the system of this solution. For example, reflected stray light is likely to be generated on the side wall of the second lens barrel, etc., and the intensity of the stray light is relatively high, reaching 2.172E-4, which also has a great impact on the imaging effect.

[0070] In the visual system 3 of the third solution, the above two conditional expressions f23 / dbs and (La + Lb) / ΔL respectively satisfy f23 / dbs = 4.17 and (La + Lb) / ΔL = 4.84. It can be seen that the values of the two conditional expressions are respectively within the ranges defined by the conditional expressions 3.93 ≤ f23 / dbs ≤ 4.30 and 4.55 < (La + Lb) / ΔL < 5.05, and the values are relatively reasonable. The stray light diagram of the imaging effect of this visual system 3 is as Figure 19 shown, from Figure 19 It can be seen that there is less stray light in the system of this solution, which can effectively reduce the stray light interference generated at positions such as the side wall of the second lens barrel. The intensity of the stray light is also significantly reduced, being 8.086E-5, which has a smaller impact on the imaging effect of the system and is beneficial to improving the imaging clarity.

[0071] Therefore, through the reasonable configuration of the system and controlling to meet the conditional expressions 3.93 ≤ f23 / dbs ≤ 4.30 and 4.55 < (La + Lb) / ΔL < 5.05, the visual system according to the present application can, while enabling the visual system to achieve the adjustment of the diopter between the +2D state and the -5D state, also effectively reduce the interference of stray light at positions such as the side wall of the second lens barrel on the imaging system, which is beneficial to improving the imaging clarity and ensuring that users can obtain clear images under different visual requirements.

[0072] In an exemplary embodiment, the visual system of the present application can satisfy the conditional formula 4.35 < das / EPD < 4.65, where das is the inner diameter of the first side end face of the first lens barrel, and EPD is the entrance pupil diameter of the visual system. By reasonably controlling the range of this conditional formula, it can not only prevent the problem of excessive light incidence and serious stray light ghost images when exceeding the upper limit value, but also prevent the problem of blocking effective light when less than the lower limit value.

[0073] In an exemplary embodiment, the visual system of the present application can satisfy the conditional formula 27.49 ≤ fz / La ≤ 34.83, where fz is the combined focal length of the first lens, the reflective polarizing element, and the quarter-wave plate, and La is the maximum distance on the optical axis from the first side end face of the first lens barrel to the second side end face of the first lens barrel. By reasonably controlling the range of this conditional formula, it can not only prevent the increase in the overall thickness of the machine and affect the user experience when exceeding the upper limit value, but also prevent the reduction of the mechanical strength of the first lens barrel when less than the lower limit value. That is, by controlling this conditional formula, the mechanical strength of the first lens barrel can be ensured without increasing the overall thickness of the machine.

[0074] In an exemplary embodiment, the visual system of the present application can satisfy the conditional formula 8.35 < dam / (CT1 + CTR + CTQ) < 10.75, where dam is the inner diameter of the second side end face of the first lens barrel, CT1 is the central thickness of the first lens on the optical axis, CTR is the central thickness of the reflective polarizing element on the optical axis, and CTQ is the central thickness of the quarter-wave plate on the optical axis. By controlling to satisfy this conditional formula, the thicknesses of the reflective polarizing element and the quarter-wave plate are restricted within a reasonable range, which can not only avoid the problem that they are too thin to affect the adhesion effect on the surface of the first lens and reduce the generation of bubbles, wrinkles, orange peel, etc., but also prevent the problem that they are too thick, resulting in the deviation of the actual light reflection position of the module from the theoretical design position and the degradation of the overall performance of the machine.

[0075] In an exemplary embodiment, the visual system of the present application can satisfy the conditional formula 7.36 ≤ (Dbs - dbm) / Δf ≤ 8.81, where Dbs is the outer diameter of the first side end face of the second lens barrel, dbm is the inner diameter of the second side end face of the second lens barrel, and Δf is the change in the effective focal length when the visual system switches from the +2D state to the -5D state. By reasonably controlling the range of this conditional formula, it can not only prevent the increase in the shape of the module and affect the volume of the whole machine when exceeding the upper limit value, but also prevent the insufficient strength of the second lens barrel and affect the mechanical performance of the module when less than the lower limit value. Thus, while ensuring the miniaturization of the system, the strength of the second lens barrel can be ensured, and the mechanical performance of the module can be guaranteed.

[0076] In an exemplary embodiment, the visual system of the present application can satisfy the conditional formula 2.55 < f1 / Das < 3.35, where f1 is the effective focal length of the first lens and Das is the outer diameter of the first side end face of the first lens barrel. By reasonably controlling the range of this conditional formula, it can not only prevent excessive light from entering due to exceeding the upper limit value, resulting in serious stray light ghosts, but also prevent the problem of blocking effective light when it is less than the lower limit value; thus, while not blocking effective light, it can avoid excessive light, which is beneficial to ensuring the imaging effect and avoiding serious stray light ghosts.

[0077] In an exemplary embodiment, the visual system of the present application can satisfy the conditional formula 2.15 < (Dbs - dam) / ΔL < 4.05, where Dbs is the outer diameter of the first side end face of the second lens barrel, dam is the inner diameter of the second side end face of the first lens barrel, and ΔL is the distance that the second lens group moves along the optical axis during the process of the visual system switching from the +2D state to the -5D state. By reasonably controlling the range of this conditional formula, it can not only prevent the protrusion length of the module from being too long when it is less than the lower limit value, resulting in too large maximum thickness of the whole machine and affecting the user experience; but also prevent the problem that it cannot accurately control the gear subdivision of the system from +2D to -5D when it exceeds the upper limit value; thus, while being beneficial to realizing the miniaturization of the system, it is also beneficial to ensuring the focus adjustment accuracy and stability of the system in different states within the range of +2D to -5D.

[0078] In an exemplary embodiment, the visual system of the present application can satisfy the conditional formula 3.7mm < |f2 / f3|×Lb < 4.1mm, where f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, and Lb is the maximum distance on the optical axis from the first side end face to the second side end face of the second lens barrel. By controlling this conditional formula, the maximum thickness of the second lens barrel can be limited within a reasonable range, which can not only prevent it from being too large and increasing the thickness of the whole machine and affecting the user experience, but also prevent it from being too small and affecting the mechanical strength of the lens barrel.

[0079] In an exemplary embodiment, the visual system of the present application can satisfy the conditional formula -11.01 ≤ R6 / Dbm ≤ -7.41, where R6 is the curvature radius of the second side face of the third lens and Dbm is the outer diameter of the second side end face of the second lens barrel. By reasonably controlling the range of this conditional formula, it can not only prevent it from exceeding the upper limit value and causing the appearance of the module to increase and affect the volume of the whole machine, but also prevent it from being less than the lower limit value and causing insufficient strength of the second lens barrel and affecting the mechanical performance of the module; thus, it can ensure both the miniaturization of the system and the strength of the second lens barrel and the mechanical performance of the module.

[0080] In an exemplary embodiment, the visual system of the present application can satisfy the conditional formula 1.35 ≤ R1 / Dam ≤ 1.70, where R1 is the radius of curvature of the first side surface of the first lens, and Dam is the outer diameter of the second side end surface of the first lens barrel. By reasonably controlling the range of this conditional formula, it can prevent it from being less than the lower limit value, which will increase the outer shape of the module and affect the volume of the whole machine, and can also prevent it from exceeding the upper limit value, which will cause insufficient strength of the first lens barrel and affect the mechanical performance of the module; thus, it can achieve both ensuring the miniaturization of the system and ensuring the strength of the first lens barrel and the mechanical performance of the module.

[0081] In an exemplary embodiment, the visual system of the present application can satisfy the conditional formula 1.28 ≤ (Das - das) / La ≤ 1.90, where Das is the outer diameter of the first side end surface of the first lens barrel, das is the inner diameter of the first side end surface of the first lens barrel, and La is the maximum distance on the optical axis from the first side end surface of the first lens barrel to the second side end surface of the first lens barrel. By reasonably controlling the range of this conditional formula, it can prevent it from exceeding the upper limit value, which will make the wall thickness of the first lens barrel too large and cause excessive difficulty in its processing and forming, and can also prevent it from being less than the lower limit value, which will cause insufficient strength of the first lens barrel and affect the mechanical performance of the module; thus, it is beneficial to make the design of the first lens barrel more reasonable, which can not only meet the strength requirements to ensure the mechanical performance of the module but also have good processing and forming performance.

[0082] In an exemplary embodiment, the visual system of the present application can satisfy the conditional formula 9.75 < Lb / Δf < 10.45, where Lb is the maximum distance on the optical axis from the first side end surface of the second lens barrel to the second side end surface of the second lens barrel, and Δf is the change in the effective focal length when the visual system switches from the +2D state to the -5D state. By reasonably controlling the range of this conditional formula, it can prevent it from exceeding the upper limit value, which will increase the thickness of the whole machine and affect the user experience, and can also prevent it from being less than the lower limit value, which will affect the mechanical strength of the second lens barrel; thus, it can achieve the miniaturization of the system while ensuring the mechanical strength of the second lens barrel and the mechanical performance of the module.

[0083] In an exemplary embodiment, the visual system of the present application can satisfy the conditional formula 1.0 < (Dbm - dbm) / CT3 < 1.6, where Dbm is the outer diameter of the second side end surface of the second lens barrel, dbm is the inner diameter of the second side end surface of the second lens barrel, and CT3 is the central thickness of the third lens on the optical axis. By reasonably controlling the range of this conditional formula, it can prevent it from exceeding the upper limit value, which will make the wall thickness of the second lens barrel too large and cause excessive difficulty in its processing and forming, and can also prevent it from being less than the lower limit value, which will cause the assembly suction surface and the bearing surface of the second lens barrel to be too small and affect the assembly of the lens barrel and the module; thus, it can ensure both the processing and forming performance and the assembly performance of the second lens barrel.

[0084] In an exemplary embodiment, the visual system of the present application can satisfy the condition 1.25 < Dbs / das < 1.45, where Dbs is the outer diameter of the first side end face of the second lens barrel, and das is the inner diameter of the first side end face of the first lens barrel. By reasonably controlling the range of this conditional formula and controlling it to be greater than the lower limit value, the outer shape of the second lens barrel can be ensured to be larger than that of the first lens barrel, ensuring the assembly of the first lens barrel. At the same time, by controlling it to be less than the upper limit value, it is possible to avoid a sudden change in the outer shape of the diopter adjustment component of the module and avoid excessive difficulty in its processing and forming.

[0085] In the visual system according to the embodiment of the present application, one or more of the first lens, the second lens, and the third lens can be aspherical lenses. The aspherical lenses have better curvature radius characteristics and have the advantages of improving distortion aberration and improving astigmatism aberration. After using the aspherical lenses, it is possible to eliminate the aberration that appears during imaging as much as possible, thereby improving the imaging quality.

[0086] In an exemplary embodiment, optionally, the above visual system may further include a filter for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the imaging surface.

[0087] On the one hand, according to the visual system of the exemplary embodiment of the present application, by providing a first lens barrel and a second lens barrel arranged in sequence from the first side to the second side along the optical axis, and a first lens group and a second lens group arranged in sequence from the first side to the second side along the optical axis, and setting the first lens group to rest on the first lens barrel and the second lens group to rest on the second lens barrel; and further setting the first lens group to include a first lens, a reflective polarizing element, and a quarter-wave plate arranged in sequence from the first side to the second side along the optical axis, and the second lens group to include a second lens, a partially reflective element, and a third lens arranged in sequence from the first side to the second side along the optical axis, wherein the first lens has a positive optical power, its first side is convex, and its second side is flat; the second lens has a positive optical power, its first side is convex, and its second side is convex; the third lens has a negative optical power, its first side is concave, and its second side is convex; and the second lens and the third lens are cemented lenses that are cemented to each other; and configuring the second lens group to be movable along the optical axis to approach or move away from the display located on the second side, so that the visual system can switch between a first state and a second state; at the same time, controlling the combined focal length f23 of the second lens and the third lens and the inner diameter dbs of the first side end face of the second lens barrel to satisfy the conditional expression 3.93 ≤ f23 / dbs ≤ 4.30, the maximum distance La on the optical axis from the first side end face of the first lens barrel to the second side end face of the first lens barrel, the maximum distance Lb on the optical axis from the first side end face of the second lens barrel to the second side end face of the second lens barrel, and the distance ΔL that the second lens group moves along the optical axis during the process of the visual system switching from the first state to the second state to satisfy the conditional expression 4.55 < (La + Lb) / ΔL < 5.05, can enable the visual system to adjust the diopter between the +2D state and the -5D state, and at the same time can also help reduce the stray light interference at the side wall of the second lens barrel, ensuring that the user can obtain a clear image under different visual needs.

[0088] On the other hand, for the visual system according to the exemplary embodiments of the present application, by providing a first lens barrel and a second lens barrel arranged in sequence from the first side to the second side along the optical axis, and a first lens group and a second lens group arranged in sequence from the first side to the second side along the optical axis, and setting the first lens group to abut against the first lens barrel and the second lens group to abut against the second lens barrel; and further setting the first lens group to include a first lens, a reflective polarizing element, and a quarter-wave plate arranged in sequence from the first side to the second side along the optical axis, and the second lens group to include a second lens, a partially reflective element, and a third lens arranged in sequence from the first side to the second side along the optical axis, wherein the first lens has a positive optical power, its first side is convex, and its second side is flat; the second lens has a positive optical power, its first side is convex, and its second side is convex; the third lens has a negative optical power, its first side is concave, and its second side is convex; and the second lens and the third lens are cemented lenses that are cemented to each other; and configuring the second lens group to be movable along the optical axis to approach or move away from the display located on the second side, so that the visual system can switch between a first state and a second state; at the same time, controlling the inner diameter das of the first side end face of the first lens barrel and the entrance pupil diameter EPD of the visual system to satisfy the conditional formula 4.35 < das / EPD < 4.65, and the maximum distance La on the optical axis from the first side end face of the first lens barrel to the second side end face of the first lens barrel, the maximum distance Lb on the optical axis from the first side end face of the second lens barrel to the second side end face of the second lens barrel, and the distance ΔL that the second lens group moves along the optical axis during the process of the visual system switching from the first state to the second state to satisfy the conditional formula 4.55 < (La + Lb) / ΔL < 5.05, can enable the visual system to adjust the diopter between the +2D state and the -5D state, and at the same time can also ensure that neither the effective light is blocked from entering the system nor the problem of serious stray light ghosts is caused by the incidence of excess light, improve the imaging quality of the system, and ensure that the user can obtain clear images under different visual requirements.

[0089] The visual system according to the exemplary embodiments of the present application adopts a folded-back architecture such as a three-piece type. By reasonably setting the system structures such as the lens barrel and the lens group, and reasonably configuring multiple parameters of the system structure and components, not only can the overall optical length be reduced, the system weight be reduced, the system be miniaturized and lightweight, and the user's comfort in use be improved; but also the zoom within the range of -5D to +2D can be achieved by moving the second lens group to meet the needs of users with different visual acuities, and users can enjoy the VR experience without wearing glasses; at the same time, the stray light interference generated at positions such as the side wall of the second lens barrel can be effectively reduced, which is beneficial to improving the imaging quality and ensuring that the user can obtain clear images under different visual requirements; in addition, the use of cemented lenses in the system has the advantages of being lightweight, good light transmittance, wear resistance, etc., and is more suitable for the manufacture of lenses for VR devices, improving the quality and adaptability of the lenses.

[0090] In addition, the present application also provides a VR device, which may include the visual system provided by any one of the above embodiments. Among them, the first side may be the human eye side, and the second side may be the display / image plane side. The VR device can achieve continuous zoom within the range of -5D to +2D, enabling users with different vision conditions to clearly enjoy the VR experience without wearing glasses. At the same time, it has characteristics such as miniaturization, light weight, high imaging quality, and stable performance, improving the user experience.

[0091] The following further describes specific embodiments of the visual system applicable to the above embodiments with reference to the accompanying drawings.

[0092] Embodiment 1

[0093] The following refers to Figure 2 Describe the visual system according to Embodiment 1 of the present application. Figure 2 The left middle figure shows a schematic structural diagram of the visual system according to Embodiment 1 of the present application in the first state (+2D state), Figure 2 The right middle figure shows a schematic structural diagram of the visual system according to Embodiment 1 of the present application in the second state (-5D state).

[0094] As Figure 2 shown, the visual system includes a first lens barrel Pa and a second lens barrel Pb, which are arranged in sequence along the optical axis from the first side to the second side. The visual system also includes a first lens group supported on the first lens barrel Pa and a second lens group supported on the second lens barrel Pb. Among them, the first lens group includes a first lens E1, a reflective polarizing element RP, and a quarter-wave plate QWP arranged in sequence along the optical axis from the first side to the second side, and the second lens group includes a second lens E2, a partial reflection element BS (not shown in the figure), and a third lens E3 arranged in sequence along the optical axis from the first side to the second side.

[0095] In this embodiment, the first lens E1 has a positive optical power, its first side S3 is a convex surface, and its second side S4 is a flat surface; the second lens E2 has a positive optical power, its first side S13 is a convex surface, and its second side S14 is a convex surface; the third lens E3 has a negative optical power, its first side S14 is a concave surface, and its second side S15 is a convex surface. The reflective polarizing element RP is arranged on the second side of the first lens E1, and the quarter-wave plate QWP is arranged on the second side of the reflective polarizing element RP. The second lens E2 and the third lens E3 are cemented lenses that are cemented to each other.

[0096] In this embodiment, the first side can be, for example, the human eye side, and the second side can be, for example, the display side. A display / image plane IMG is provided on the second side of the visual system. The first lens group including the first lens E1, the reflective polarizing element RP, and the quarter-wave plate QWP and the first lens barrel Pa are relatively fixed in distance along the optical axis direction from the display / image plane IMG; the second lens group including the second lens E2, the partially reflective element BS, and the third lens E3 and the second lens barrel Pb can move along the optical axis direction to approach or move away from the display / image plane IMG, and during this process, the visual system can achieve zooming within the range of -5D to +2D. Figure 2 The left middle figure shows a schematic structural diagram of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the position closest to the display / image plane IMG. At this time, the visual system is in the +2D state. Figure 2 The right middle figure shows a schematic structural diagram of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the position farthest from the display / image plane IMG. At this time, the visual system is in the -5D state.

[0097] Table 1 shows the basic parameters of the visual system in Embodiment 1, where the units of the radius of curvature and the thickness / distance are both millimeters (mm).

[0098] Table 1

[0099]

[0100] The parameters D1 to D5 in Table 1 can be understood as follows: D5 can be understood as the value along the optical axis from the first side of the filter and / or the protective glass IR / CG provided on the first side of the image plane IMG to the second side of the third lens E3; D4 can be understood as the value along the optical axis from the first side of the second lens E2 to the second side of the quarter-wave plate QWP; D3 can be understood as the value along the optical axis from the second side of the quarter-wave plate QWP to the first side of the second lens E2; D2 can be understood as the value along the optical axis from the first side of the second lens E2 to the second side of the quarter-wave plate QWP again; D1 can be understood as the value of the virtual image distance of the visual system according to this embodiment. During the process of the visual system achieving zooming by moving the second lens group and the second lens barrel Pb along the optical axis, the values of the above parameters D1 to D5 will all change accordingly. The visual system is in Figure 2 the +2D state shown in the left middle figure and Figure 2 the -5D state shown in the right middle figure, and the values of the parameters D1 to D5 are shown in Table 2 below.

[0101] Table 2

[0102]

[0103] In Embodiment 1, the first side surface S3 of the first lens E1, the first side surface S13 and the second side surface S14 of the second lens E2, and the first side surface S14 and the second side surface S15 of the third lens E3 are all aspherical surfaces. The aspherical surface profiles can be defined by, but are not limited to, the following aspherical formula:

[0104] (1)

[0105] Wherein, is the sag of the aspherical surface along the optical axis at a position with a height of h from the vertex of the aspherical surface; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the i -th order correction coefficient of the aspherical surface. Table 3 below gives the high-order term coefficients A 4 , A 6 , A 8 , A 10 , A 12 , A 14 , A 16 , A 18 and A 20 that can be used for the aspherical surfaces S3 and S13 - S15 in Embodiment 1.

[0106] Table 3

[0107]

[0108] Referring to Table 10, for the visual system according to this embodiment, the numerical values of its multiple structural parameters are respectively shown in the column of 'Embodiment 1' in Table 10. Among them, das is the inner diameter of the first side end face of the first lens barrel Pa, dam is the inner diameter of the second side end face of the first lens barrel Pa, Das is the outer diameter of the first side end face of the first lens barrel Pa, Dam is the outer diameter of the second side end face of the first lens barrel Pa, dbs is the inner diameter of the first side end face of the second lens barrel Pb, dbm is the inner diameter of the second side end face of the second lens barrel Pb, Dbs is the outer diameter of the first side end face of the second lens barrel Pb, Dbm is the outer diameter of the second side end face of the second lens barrel Pb, La is the maximum distance from the first side end face to the second side end face of the first lens barrel Pa on the optical axis, and Lb is the maximum distance from the first side end face to the second side end face of the second lens barrel Pb on the optical axis. The numerical values of the above-mentioned various structural parameters of the visual system according to this embodiment are respectively corresponding and consistent in two different focal length states of +2D and -5D. The units of the above-mentioned various parameters shown in Table 10 are all millimeters (mm), and for the schematic illustration of the above-mentioned various parameters in the structural diagram of the visual system, reference can be made to Figure 1 。

[0109] Embodiment 2

[0110] The following is a reference Figure 3 to describe the visual system according to Embodiment 2 of the present application.

[0111] As Figure 3 shown, similar to the visual system in Embodiment 1, the visual system in this embodiment also includes a first lens barrel Pa and a second lens barrel Pb, which are arranged in sequence along the optical axis from the first side to the second side. It also includes a first lens group supported on the first lens barrel Pa and a second lens group supported on the second lens barrel Pb. Among them, the first lens group includes a first lens E1, a reflective polarizing element RP, and a quarter-wave plate QWP arranged in sequence along the optical axis from the first side to the second side, and the second lens group includes a second lens E2, a partially reflective element BS (not shown in the figure), and a third lens E3 arranged in sequence along the optical axis from the first side to the second side.

[0112] Similar to Embodiment 1, in this embodiment, the first side can be, for example, the human eye side, and the second side can be, for example, the display side. A display / image plane IMG is provided on the second side of the visual system. The first lens group including the first lens E1, the reflective polarizing element RP, and the quarter-wave plate QWP and the first lens barrel Pa are relatively fixed in distance along the optical axis direction from the display / image plane IMG; the second lens group including the second lens E2, the partially reflective element BS, and the third lens E3 and the second lens barrel Pb can move along the optical axis direction to approach or move away from the display / image plane IMG. During this process, the visual system can achieve zooming within the range of -5D to +2D. Figure 3The left-middle figure shows a schematic structural diagram of the visual system when the second lens group and the second lens barrel Pb are moved along the optical axis to the position closest to the display / image plane IMG. At this time, the visual system is in the first state (+2D state). Figure 3 The right-middle figure shows a schematic structural diagram of the visual system when the second lens group and the second lens barrel Pb are moved along the optical axis to the position farthest from the display / image plane IMG. At this time, the visual system is in the second state (-5D state).

[0113] The basic parameter table of the visual system of this embodiment is the same as Table 1 in Embodiment 1, the numerical values of parameters D1 to D5 are the same as those in Table 2 of Embodiment 1, and the high-order term coefficient table of the aspherical mirror surface is the same as Table 3 in Embodiment 1.

[0114] The numerical values of the structural parameters of the visual system of this embodiment are shown in the 'Embodiment 2' column of Table 10. Among them, the specific descriptions of the meanings represented by the parameters are the same as those described in Embodiment 1 above and will not be elaborated here.

[0115] Embodiment 3

[0116] The following refers to Figure 4 Describe the visual system according to Embodiment 3 of the present application.

[0117] As Figure 4 shown, similar to the visual system in Embodiment 1, the visual system in this embodiment also includes a first lens barrel Pa and a second lens barrel Pb, which are arranged in sequence along the optical axis from the first side to the second side. It also includes a first lens group supported on the first lens barrel Pa and a second lens group supported on the second lens barrel Pb. Among them, the first lens group includes a first lens E1, a reflective polarizing element RP, and a quarter-wave plate QWP arranged in sequence along the optical axis from the first side to the second side, and the second lens group includes a second lens E2, a partial reflection element BS (not shown in the figure), and a third lens E3 arranged in sequence along the optical axis from the first side to the second side.

[0118] Similar to Embodiment 1, in this embodiment, the first side can be, for example, the human eye side, and the second side can be, for example, the display side. A display / image plane IMG is provided on the second side of the visual system. The first lens group including the first lens E1, the reflective polarizing element RP, and the quarter-wave plate QWP and the first lens barrel Pa are relatively fixed in the distance along the optical axis direction from the display / image plane IMG; the second lens group including the second lens E2, the partial reflection element BS, and the third lens E3 and the second lens barrel Pb can move along the optical axis direction to approach or move away from the display / image plane IMG. During this process, the visual system can achieve zooming within the range of -5D to +2D. Figure 4The left-middle figure shows a schematic structural diagram of the visual system when the second lens group and the second lens barrel Pb are moved along the optical axis to the position closest to the display / image plane IMG. At this time, the visual system is in the first state (+2D state). Figure 4 The right-middle figure shows a schematic structural diagram of the visual system when the second lens group and the second lens barrel Pb are moved along the optical axis to the position farthest from the display / image plane IMG. At this time, the visual system is in the second state (-5D state).

[0119] The basic parameter table of the visual system in this embodiment is also the same as Table 1 in Embodiment 1. The numerical values of parameters D1 to D5 are also the same as those in Table 2 of Embodiment 1. The high-order term coefficient table of the aspherical mirror surface is also the same as Table 3 in Embodiment 1.

[0120] The numerical values of the structural parameters of the visual system in this embodiment are shown in the 'Embodiment 3' column of Table 10. Among them, the specific descriptions of the meanings represented by the parameters are the same as those described in Embodiment 1 above and will not be elaborated here.

[0121] Figure 5 The MTF curves of the visual systems of Embodiment 1, Embodiment 2, and Embodiment 3 in the +2D state are shown. Figure 6 The MTF curves of the visual systems of Embodiment 1, Embodiment 2, and Embodiment 3 in the -5D state are shown. The MTF (modulation transfer function) curve can represent the optical modulation function values corresponding to different spatial frequencies. From Figure 5 and Figure 6 It can be seen that the visual systems given in Embodiment 1, Embodiment 2, and Embodiment 3 can achieve good imaging quality in two different focal length states of +2D and -5D.

[0122] Embodiment 4

[0123] The following refers to Figure 7 Describe the visual system according to Embodiment 4 of the present application. Figure 7 The left-middle figure shows a schematic structural diagram of the visual system according to Embodiment 4 of the present application when it is in the first state (+2D state). Figure 7 The right-middle figure shows a schematic structural diagram of the visual system according to Embodiment 4 of the present application when it is in the second state (-5D state).

[0124] As Figure 7As shown, the visual system includes a first barrel Pa and a second barrel Pb, which are arranged in sequence along the optical axis from the first side to the second side. The visual system further includes a first lens group supported on the first barrel Pa and a second lens group supported on the second barrel Pb. Among them, the first lens group includes a first lens E1, a reflective polarizing element RP, and a quarter-wave plate QWP arranged in sequence along the optical axis from the first side to the second side. The second lens group includes a second lens E2, a partial reflection element BS (not shown in the figure), and a third lens E3 arranged in sequence along the optical axis from the first side to the second side.

[0125] In this embodiment, the first lens E1 has a positive optical power. Its first side S3 is a convex surface, and its second side S4 is a plane. The second lens E2 has a positive optical power. Its first side S13 is a convex surface, and its second side S14 is a convex surface. The third lens E3 has a negative optical power. Its first side S14 is a concave surface, and its second side S15 is a convex surface. The reflective polarizing element RP is disposed on the second side of the first lens E1, and the quarter-wave plate QWP is disposed on the second side of the reflective polarizing element RP. The second lens E2 and the third lens E3 are cemented lenses that are cemented to each other.

[0126] In this embodiment, the first side can be, for example, the human eye side, and the second side can be, for example, the display side. A display / image plane IMG is provided on the second side of the visual system. The first lens group including the first lens E1, the reflective polarizing element RP, and the quarter-wave plate QWP and the first barrel Pa are relatively fixed in distance along the optical axis direction from the display / image plane IMG. The second lens group including the second lens E2, the partial reflection element BS, and the third lens E3 and the second barrel Pb can move along the optical axis direction to approach or move away from the display / image plane IMG. During this process, the visual system can achieve zooming within the range of -5D to +2D. Figure 7 The left middle figure shows a schematic structural diagram of the visual system when the second lens group and the second barrel Pb move along the optical axis to the position closest to the display / image plane IMG. At this time, the visual system is in the +2D state. Figure 7 The right middle figure shows a schematic structural diagram of the visual system when the second lens group and the second barrel Pb move along the optical axis to the position farthest from the display / image plane IMG. At this time, the visual system is in the -5D state.

[0127] Table 4 shows the basic parameters of the visual system in Embodiment 4. Among them, the units of the radius of curvature and the thickness / distance are both millimeters (mm).

[0128] Table 4

[0129]

[0130] According to this embodiment, when the visual system is in the +2D state and the -5D state respectively, the values ​​of the parameters D1 to D5 in Table 4 are respectively shown in Table 5 below. The meanings of the parameters D1 to D5 can refer to the description in Example 1.

[0131] Table 5

[0132]

[0133] In this embodiment, the first side surface S3 of the first lens E1, the first side surface S13 and the second side surface S14 of the second lens E2, and the first side surface S14 and the second side surface S15 of the third lens E3 are all aspherical surfaces. Table 6 shows the high-order coefficients of the aspherical surfaces S3 and S13-S15 that can be used in Embodiment 4. A 4 , A 6 , A 8 , A 10 , A 12 , A 14 , A 16 , A 18 and A 20 , wherein the surface shape of each aspheric surface can be defined by the formula (1) given in the above embodiment 1.

[0134] Table 6

[0135]

[0136] Referring to Table 10, the values ​​of the structural parameters of the visual system of this embodiment are respectively shown in the 'Example 4' column in Table 10, wherein the specific description of the meaning represented by each parameter is the same as that in the above Example 1 and will not be repeated here.

[0137] Example 5

[0138] The following reference Figure 8 Describe the visual system according to Example 5 of the present application.

[0139] like Figure 8As shown, similar to the visual system in Embodiment 4, the visual system in this embodiment also includes a first lens barrel Pa and a second lens barrel Pb, which are arranged in sequence along the optical axis from the first side to the second side. It also includes a first lens group resting on the first lens barrel Pa and a second lens group resting on the second lens barrel Pb. Among them, the first lens group includes a first lens E1, a reflective polarizing element RP, and a quarter-wave plate QWP arranged in sequence along the optical axis from the first side to the second side, and the second lens group includes a second lens E2, a partially reflective element BS (not shown in the figure), and a third lens E3 arranged in sequence along the optical axis from the first side to the second side.

[0140] Similar to Embodiment 4, in this embodiment, the first side can be, for example, the human eye side, and the second side can be, for example, the display side. A display / image plane IMG is provided on the second side of the visual system. The first lens group including the first lens E1, the reflective polarizing element RP, and the quarter-wave plate QWP and the first lens barrel Pa are relatively fixed in distance from the display / image plane IMG along the optical axis direction; the second lens group including the second lens E2, the partially reflective element BS, and the third lens E3 and the second lens barrel Pb can move along the optical axis direction to approach or move away from the display / image plane IMG. During this process, the visual system can achieve zooming within the range of -5D to +2D. Figure 8 The left middle figure shows a schematic structural diagram of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the position closest to the display / image plane IMG. At this time, the visual system is in the first state (+2D state). Figure 8 The right middle figure shows a schematic structural diagram of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the position farthest from the display / image plane IMG. At this time, the visual system is in the second state (-5D state).

[0141] The basic parameter table of the visual system in this embodiment is the same as Table 4 in Embodiment 4, the numerical values of parameters D1 to D5 are the same as those in Table 5 of Embodiment 4, and the high-order term coefficient table of the aspherical mirror surface is the same as Table 6 in Embodiment 4.

[0142] The numerical values of the structural parameters of the visual system in this embodiment are shown in the 'Embodiment 5' column of Table 10. Among them, the specific descriptions of the meanings represented by each parameter are the same as those described in Embodiment 1 above, and will not be elaborated here.

[0143] Embodiment 6

[0144] The following refers to Figure 9 Describe the visual system according to Embodiment 6 of the present application.

[0145] As Figure 9As shown, similar to the visual system in Embodiment 4, the visual system in this embodiment also includes a first barrel Pa and a second barrel Pb, which are arranged in sequence along the optical axis from the first side to the second side. It also includes a first lens group resting on the first barrel Pa and a second lens group resting on the second barrel Pb. Among them, the first lens group includes a first lens E1, a reflective polarizing element RP, and a quarter-wave plate QWP arranged in sequence along the optical axis from the first side to the second side, and the second lens group includes a second lens E2, a partial reflection element BS (not shown in the figure), and a third lens E3 arranged in sequence along the optical axis from the first side to the second side.

[0146] Similar to Embodiment 4, in this embodiment, the first side can be, for example, the human eye side, and the second side can be, for example, the display side. A display / image plane IMG is provided on the second side of the visual system. The first lens group including the first lens E1, the reflective polarizing element RP, and the quarter-wave plate QWP and the first barrel Pa are relatively fixed in distance along the optical axis direction from the display / image plane IMG; the second lens group including the second lens E2, the partial reflection element BS, and the third lens E3 and the second barrel Pb can move along the optical axis direction to approach or move away from the display / image plane IMG. During this process, the visual system can achieve zooming in the range of -5D to +2D. Figure 9 The left figure in the middle shows a schematic structural diagram of the visual system when the second lens group and the second barrel Pb move along the optical axis to the position closest to the display / image plane IMG. At this time, the visual system is in the first state (+2D state). Figure 9 The right figure in the middle shows a schematic structural diagram of the visual system when the second lens group and the second barrel Pb move along the optical axis to the position farthest from the display / image plane IMG. At this time, the visual system is in the second state (-5D state).

[0147] The basic parameter table of the visual system in this embodiment is also the same as Table 4 in Embodiment 4, the numerical values of parameters D1 to D5 are also the same as Table 5 in Embodiment 4, and the high-order term coefficient table of the aspherical mirror surface is also the same as Table 6 in Embodiment 4.

[0148] The numerical values of the structural parameters of the visual system in this embodiment are shown in the 'Embodiment 6' column of Table 10. Among them, the specific descriptions of the meanings represented by each parameter are the same as those in Embodiment 1 described above and will not be elaborated here.

[0149] Figure 10 Shows the MTF curves of the visual systems of Embodiment 4, Embodiment 5, and Embodiment 6 in the +2D state, Figure 11 Shows the MTF curves of the visual systems of Embodiment 4, Embodiment 5, and Embodiment 6 in the -5D state. From Figure 10 and Figure 11It can be seen that the visual systems given in Embodiment 4, Embodiment 5, and Embodiment 6 can achieve good imaging quality in two different focal length states of +2D and -5D.

[0150] Embodiment 7

[0151] The following refers to Figure 12 Describe the visual system according to Embodiment 7 of the present application. Figure 12 The left middle figure shows a schematic structural diagram of the visual system according to Embodiment 7 of the present application when in the first state (+2D state), Figure 12 The right middle figure shows a schematic structural diagram of the visual system according to Embodiment 7 of the present application when in the second state (-5D state).

[0152] As Figure 12 shown, the visual system includes a first lens barrel Pa and a second lens barrel Pb, which are arranged in sequence along the optical axis from the first side to the second side. The visual system further includes a first lens group resting on the first lens barrel Pa and a second lens group resting on the second lens barrel Pb. Among them, the first lens group includes a first lens E1, a reflective polarizing element RP, and a quarter-wave plate QWP arranged in sequence along the optical axis from the first side to the second side, and the second lens group includes a second lens E2, a partial reflection element BS (not shown in the figure), and a third lens E3 arranged in sequence along the optical axis from the first side to the second side.

[0153] In this embodiment, the first lens E1 has a positive optical power, its first side S3 is a convex surface, and its second side S4 is a flat surface; the second lens E2 has a positive optical power, its first side S13 is a convex surface, and its second side S14 is a convex surface; the third lens E3 has a negative optical power, its first side S14 is a concave surface, and its second side S15 is a convex surface. The reflective polarizing element RP is disposed on the second side of the first lens E1, and the quarter-wave plate QWP is disposed on the second side of the reflective polarizing element RP. The second lens E2 and the third lens E3 are cemented lenses that are cemented to each other.

[0154] In this embodiment, the first side can be, for example, the human eye side, and the second side can be, for example, the display side. A display / image plane IMG is provided on the second side of the visual system. The first lens group including the first lens E1, the reflective polarizing element RP, and the quarter-wave plate QWP and the first lens barrel Pa are relatively fixed in distance along the optical axis direction from the display / image plane IMG; the second lens group including the second lens E2, the partial reflection element BS, and the third lens E3 and the second lens barrel Pb can move along the optical axis direction to approach or move away from the display / image plane IMG. During this process, the visual system can achieve zooming within the range of -5D to +2D. Figure 12The left middle figure shows a schematic diagram of the visual system when the second lens group and the second lens barrel Pb are moved along the optical axis to the position closest to the display / image plane IMG. At this time, the visual system is in the +2D state. Figure 12 The right middle figure shows a schematic diagram of the visual system when the second lens group and the second lens barrel Pb are moved along the optical axis to the position farthest from the display / image plane IMG. At this time, the visual system is in the -5D state.

[0155] Table 7 shows the basic parameters of the visual system of Example 7, where the units of the radius of curvature and the thickness / distance are both millimeters (mm).

[0156] Table 7

[0157]

[0158] When the visual system according to this embodiment is in the +2D state and the -5D state respectively, the values corresponding to the parameters D1 to D5 in Table 7 are shown in Table 8 below. The meanings of the parameters D1 to D5 can be referred to the description in Example 1.

[0159] Table 8

[0160]

[0161] In this embodiment, the first side surface S3 of the first lens E1, the first side surface S13 and the second side surface S14 of the second lens E2, and the first side surface S14 and the second side surface S15 of the third lens E3 are all aspherical surfaces. Table 9 shows the higher-order term coefficients of the aspherical surfaces S3 and S13 - S15 that can be used in Example 7. A 4 , A 6 , A 8 , A 10 , A 12 , A 14 , A 16 , A 18 and A 20 , where the aspherical surface profiles can be defined by the formula (1) given in Example 1 above.

[0162] Table 9

[0163]

[0164] Referring to Table 10, the numerical values of the structural parameters of the visual system of this embodiment are shown in the column of 'Embodiment 7' in Table 10. Among them, the specific descriptions of the meanings represented by the parameters are the same as those in Embodiment 1 described above, and will not be elaborated here.

[0165] Embodiment 8

[0166] The following refers to Figure 13 Describe the visual system according to Embodiment 8 of the present application.

[0167] As Figure 13 shown, similar to the visual system in Embodiment 7, the visual system in this embodiment also includes a first lens barrel Pa and a second lens barrel Pb, which are arranged in sequence along the optical axis from the first side to the second side. It also includes a first lens group supported on the first lens barrel Pa and a second lens group supported on the second lens barrel Pb. Among them, the first lens group includes a first lens E1, a reflective polarizing element RP, and a quarter-wave plate QWP arranged in sequence along the optical axis from the first side to the second side, and the second lens group includes a second lens E2, a partial reflection element BS (not shown in the figure), and a third lens E3 arranged in sequence along the optical axis from the first side to the second side.

[0168] Similar to Embodiment 7, in this embodiment, the first side can be, for example, the human eye side, and the second side can be, for example, the display side. A display / image plane IMG is provided on the second side of the visual system. The first lens group including the first lens E1, the reflective polarizing element RP, and the quarter-wave plate QWP and the first lens barrel Pa are relatively fixed in distance along the optical axis direction from the display / image plane IMG; the second lens group including the second lens E2, the partial reflection element BS, and the third lens E3 and the second lens barrel Pb can move along the optical axis direction to approach or move away from the display / image plane IMG. During this process, the visual system can achieve zooming in the range of -5D to +2D. Figure 13 The left figure in the middle shows a schematic structural diagram of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the position closest to the display / image plane IMG. At this time, the visual system is in the first state (+2D state). Figure 13 The right figure in the middle shows a schematic structural diagram of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the position farthest from the display / image plane IMG. At this time, the visual system is in the second state (-5D state).

[0169] The basic parameter table of the visual system of this embodiment is the same as Table 7 in Embodiment 7, the numerical values of parameters D1 to D5 are the same as Table 8 in Embodiment 7, and the high-order term coefficient table of the aspherical mirror surface is the same as Table 9 in Embodiment 7.

[0170] The numerical values of the structural parameters of the visual system of this embodiment are shown in the column of 'Embodiment 8' in Table 10. Among them, the specific descriptions of the meanings represented by the parameters are the same as those in Embodiment 1 described above, and will not be elaborated here.

[0171] Embodiment 9

[0172] The following refers to Figure 14 Describe the visual system according to Embodiment 9 of the present application.

[0173] As Figure 14 shown, similar to the visual system in Embodiment 7, the visual system in this embodiment also includes a first lens barrel Pa and a second lens barrel Pb, which are arranged in sequence along the optical axis from the first side to the second side. It also includes a first lens group supported on the first lens barrel Pa and a second lens group supported on the second lens barrel Pb. Among them, the first lens group includes a first lens E1, a reflective polarizing element RP, and a quarter-wave plate QWP arranged in sequence along the optical axis from the first side to the second side, and the second lens group includes a second lens E2, a partially reflective element BS (not shown in the figure), and a third lens E3 arranged in sequence along the optical axis from the first side to the second side.

[0174] Similar to Embodiment 7, in this embodiment, the first side can be, for example, the human eye side, and the second side can be, for example, the display side. A display / image plane IMG is provided on the second side of the visual system. The first lens group including the first lens E1, the reflective polarizing element RP, and the quarter-wave plate QWP and the first lens barrel Pa are relatively fixed in the distance along the optical axis direction from the display / image plane IMG; the second lens group including the second lens E2, the partially reflective element BS, and the third lens E3 and the second lens barrel Pb can move along the optical axis direction to approach or move away from the display / image plane IMG. During this process, the visual system can achieve zooming in the range of -5D to +2D. Figure 14 The left figure in the middle shows a schematic structural diagram of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the position closest to the display / image plane IMG. At this time, the visual system is in the first state (+2D state). Figure 14 The right figure in the middle shows a schematic structural diagram of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the position farthest from the display / image plane IMG. At this time, the visual system is in the second state (-5D state).

[0175] The basic parameter table of the visual system of this embodiment is also the same as Table 7 in Embodiment 7, the numerical values of parameters D1 to D5 are also the same as those in Table 8 in Embodiment 7, and the high-order term coefficient table of the aspherical mirror surface is also the same as Table 9 in Embodiment 7.

[0176] The numerical values of the structural parameters of the visual system in this embodiment are shown in the column of 'Embodiment 9' in Table 10. Among them, the specific descriptions of the meanings represented by the parameters are the same as those in Embodiment 1 described above, and will not be elaborated here.

[0177] Figure 15 Fig. shows the MTF curves of the visual systems of Embodiment 7, Embodiment 8, and Embodiment 9 when in the +2D state. Figure 16 Fig. shows the MTF curves of the visual systems of Embodiment 7, Embodiment 8, and Embodiment 9 when in the -5D state. As can be seen from Figure 15 and Figure 16 it can be seen that the visual systems given in Embodiment 7, Embodiment 8, and Embodiment 9 can achieve good imaging quality in both the +2D and -5D states with different focal lengths.

[0178] Table 10

[0179]

[0180] In addition, in Embodiments 1 to 9, the effective focal length f1 of the first lens, the effective focal length f2 of the second lens, the effective focal length f3 of the third lens, the combined focal length f23 of the second lens and the third lens, the combined focal length fz of the first lens, the reflective polarizing element, and the quarter-wave plate, the entrance pupil diameter EPD of the visual system, the distance ΔL that the second lens group moves along the optical axis during the process of the visual system switching from the +2D state to the -5D state, and the change amount Δf of the effective focal length of the system when the visual system switches from the +2D state to the -5D state are shown in Table 11 below.

[0181] Table 11

[0182]

[0183] And, Embodiments 1 to 9 respectively satisfy the conditions shown in Table 12 below. The numerical values of the visual systems of each embodiment in Embodiments 1 to 9 corresponding to each conditional formula in Table 12 in the +2D and -5D states with different focal lengths are respectively consistent.

[0184] Table 12

[0185]

[0186] The present application also provides an imaging device, which is provided with an electronic photosensitive element for imaging. The electronic photosensitive element can be a charge coupled device (CCD) or a complementary metal oxide semiconductor element (CMOS). The imaging device can be an independent imaging device such as a digital camera, or an imaging module integrated on a mobile electronic device such as a mobile phone. The imaging device is equipped with the visual system described above.

[0187] The above description is only a preferred embodiment of the present application and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of protection involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the concept of the present application. For example, the technical solutions formed by mutually replacing the above features with the technical features (but not limited to) having similar functions disclosed in the present application.

Claims

1. A visual system, characterized in that: It includes a lens barrel group and a lens group, wherein: The lens barrel assembly comprises a first lens barrel and a second lens barrel which are sequentially arranged from a first side to a second side along the optical axis; The lens group includes a first lens group and a second lens group arranged in sequence from the first side to the second side along the optical axis; the first lens group is supported by the first lens barrel, and the second lens group is supported by the second lens barrel; The first lens group includes a first lens, a reflective polarizing element and a quarter wave plate arranged in sequence from the first side to the second side along the optical axis, and the second lens group includes a second lens, a partial reflective element and a third lens arranged in sequence from the first side to the second side along the optical axis; wherein the first lens has positive optical power, and its first side surface is convex, and its second side surface is flat; the second lens has positive optical power, and its first side surface is convex, and its second side surface is convex; the third lens has negative optical power, and its first side surface is concave, and its second side surface is convex; and the second lens is glued to the third lens; The second lens group is configured to be movable along the optical axis to be closer to or farther from the display located at the second side, and to switch the visual system between a first state and a second state; The number of lenses having optical power in the visual system is three; and The visual system meets the following requirements: 3.93≤f23 / dbs≤4.30, 4.55<(La+Lb) / ΔL<5.05, Among them, f23 is the combined focal length of the second lens and the third lens, dbs is the inner diameter of the first side end surface of the second lens barrel, La is the maximum distance from the first side end surface of the first lens barrel to the second side end surface of the first lens barrel on the optical axis, Lb is the maximum distance from the first side end surface of the second lens barrel to the second side end surface of the second lens barrel on the optical axis, and ΔL is the distance that the second lens group moves along the optical axis when the visual system switches from the first state to the second state.

2. The visual system according to claim 1, characterized in that: The inner diameter das of the first side end surface of the first lens barrel and the entrance pupil diameter EPD of the visual system satisfy: 4.35 <das / EPD<4.65。 3. The visual system according to claim 1, characterized in that: The combined focal length fz of the first lens, the reflective polarizing element and the quarter-wave plate satisfies: 27.49≤fz / La≤34.

83.

4. The visual system according to claim 1, characterized in that: The inner diameter dam of the second side end surface of the first lens barrel, the center thickness CT1 of the first lens 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: 8.35 <dam / (CT1+CTR+CTQ)<10.75。 5. The visual system according to claim 1, characterized in that: The outer diameter Dbs of the first side end surface of the second lens barrel, the inner diameter dbm of the second side end surface of the second lens barrel and the change Δf of the effective focal length of the visual system when switching from the first state to the second state satisfy: 7.36≤(Dbs-dbm) / Δf≤8.

81.

6. The visual system according to claim 1, characterized in that: The effective focal length f1 of the first lens and the outer diameter Das of the first side end surface of the first lens barrel satisfy: 2.55 <f1 / Das<3.35。 7. The visual system according to claim 1, characterized in that: The outer diameter Dbs of the first side end surface of the second lens barrel and the inner diameter dam of the second side end surface of the first lens barrel satisfy: 2.15<(Dbs-dam) / ΔL<4.

05.

8. The visual system according to claim 1, characterized in that: The effective focal length f2 of the second lens and the effective focal length f3 of the third lens satisfy: <h2 style=";text-align:left;direction:ltr">3.7mm<<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr"> f2 / f3<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr"> ×Lb<4.1mm。 9. The visual system according to claim 1, characterized in that: The curvature radius R6 of the second side surface of the third lens and the outer diameter Dbm of the second side end surface of the second lens barrel satisfy: -11.01≤R6 / Dbm≤-7.

41.

10. The visual system according to claim 1, characterized in that: The curvature radius R1 of the first side surface of the first lens and the outer diameter Dam of the second side end surface of the first lens barrel satisfy: 1.35≤R1 / Dam≤1.

70.

11. The visual system according to claim 1, characterized in that: The outer diameter Das of the first side end surface of the first lens barrel and the inner diameter das of the first side end surface of the first lens barrel satisfy: 1.28≤(Das-das) / La≤1.

90.

12. The visual system according to claim 1, characterized in that: The change Δf of the effective focal length of the visual system when switching from the first state to the second state satisfies: 9.75 <Lb / Δf<10.45。 13. The visual system according to claim 1, characterized in that: The outer diameter Dbm of the second side end surface of the second lens barrel, the inner diameter dbm of the second side end surface of the second lens barrel and the center thickness CT3 of the third lens on the optical axis satisfy: 1.0<(Dbm-dbm) / CT3<1.

6.

14. The visual system according to claim 1, characterized in that: The outer diameter Dbs of the first side end surface of the second lens barrel and the inner diameter das of the first side end surface of the first lens barrel satisfy: 1.25 <Dbs / das<1.45。

Images