Visual system

Abstract

The invention discloses a visual system. The visual system comprises a first lens cone and a second lens cone which are sequentially arranged from a first side to a second side along an optical axis, and a first lens group and a second lens group which are respectively supported on the two lens cones, the first lens group sequentially comprises a first lens, a reflective polarizing element and a quarter-wave plate, and the second lens group sequentially comprises a second lens, a partial reflection element and a third lens; the focal 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 lens and the third lens are glued; the second lens group can move along the optical axis to be close to or far away from the display on the second side, so that the system is switched between the first state and the second state; 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 meet the condition that f23 / dbs is larger than or equal to 3.93 and smaller than or equal to 4.30. The maximum heights La and Lb of the first lens barrel and the second lens barrel along the optical axis and the distance delta L of the second lens group moving along the optical axis in the process that the system is switched from the first state to the second state meet the condition that delta L is 4.55 lt. (La + Lb) / [delta] Llt; 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, wherein 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 is supported by the first lens barrel, and the second lens group is supported by 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 partial reflection 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 the second side surface is flat; the second lens has positive optical power, and its first side surface is convex, and the second side surface is convex; the third lens has negative optical power, and its first side surface is concave, and the second side surface is convex; and the second lens is glued to the third lens. The second lens group 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 the first state and the second state. The visual system can satisfy the conditions 3.93≤f23 / dbs≤4.30 and 4.55<(La+Lb) / ΔL<5.05, wherein 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 from the first side end face of the first lens barrel to the second side end face of the first lens barrel on the optical axis, Lb is the maximum distance from the first side end face of the second lens barrel to the second side end face of the second lens barrel on the optical axis, and ΔL is the distance the second lens group moves along the optical axis when the visual system switches from the first state to the second state.

[0005] In one embodiment, 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 may 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 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 may satisfy: 27.49≤fz / La≤34.83.

[0007] In one embodiment, the inner diameter dam of the second side end surface of the first lens barrel and 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 may satisfy: 8.35 <dam / (CT1+CTR+CTQ)<10.75。

[0008] In one embodiment, 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 when the visual system switches from the first state to the second state can 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 surface 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 surface of the second lens barrel, the inner diameter dam of the second side end surface of the first lens barrel, and the distance ΔL that the second lens group moves along the optical axis when the visual system switches 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 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 may satisfy: 3.7mm<|f2 / f3|×Lb<4.1mm.

[0012] In one embodiment, the radius of curvature 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 may satisfy: -11.01≤R6 / Dbm≤-7.41.

[0013] In one embodiment, a curvature radius R1 of the first side surface of the first lens and an outer diameter Dam of the second side end surface 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 surface of the first lens barrel, the inner diameter das of the first side end surface of the first lens barrel, and the maximum distance La 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 may satisfy: 1.28≤(Das-das) / La≤1.90.

[0015] In one embodiment, the maximum distance Lb 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 the change Δf of the effective focal length when the visual system switches from the first state to the second state can satisfy: 9.75 <Lb / Δf<10.45。

[0016] In one embodiment, 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 may satisfy: 1.0<(Dbm-dbm) / CT3<1.6.

[0017] In one embodiment, 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 may satisfy: 1.25 <Dbs / das<1.45。

[0018] The visual system disclosed in the present application includes a lens barrel group and a lens group, wherein 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, and 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, wherein 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 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 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 a convex surface, and the second side surface is a plane; the second lens has positive optical power, and its first side surface is a convex surface, and the second side surface is a convex surface; the third lens has negative optical power, and its first side surface is a concave surface, and the second side surface is a convex surface; and the second lens and the third lens are mutually bonded cemented lenses. 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 the visual system is switched between the first state and the second state. Through the above configuration of the visual system, 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 formula 3.93≤f23 / dbs≤4.30, the maximum distance La from the first side end face of the first lens barrel to the second side end face of the first lens barrel on the optical axis, the maximum distance Lb from the first side end face of the second lens barrel to the second side end face of the second lens barrel on the optical axis and the distance ΔL moved by the second lens group along the optical axis during the visual system switching from the first state to the second state meet the conditional formula 4.55<(La+Lb) / ΔL<5.05, the visual system can realize that the diopter can be adjusted from the +2D state to the -5D state, and it can also 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other features, purposes and advantages of the present application will become more apparent through the following detailed description of non-limiting embodiments in conjunction with the accompanying drawings. In the accompanying drawings: Figure 1 A schematic diagram showing the structure and some parameters of a visual system according to an exemplary embodiment of the present application is shown; Figure 2 The left figure and the right figure in the figure respectively show the structural schematic diagrams of the visual system according to Example 1 of the present application when it is in the first state (+2D state) and the second state (-5D state); Figure 3 The left figure and the right figure in the figure respectively show the structural schematic diagrams of the visual system according to Example 2 of the present application when it is in the first state (+2D state) and the second state (-5D state); Figure 4 The left figure and the right figure in the figure respectively show the structural schematic diagrams of the visual system according to Example 3 of the present application when it is in the first state (+2D state) and the second state (-5D state); Figure 5 The figure shows the MTF (Modulation Transfer Function) diagram when the visual system according to Embodiment 1, Embodiment 2 and Embodiment 3 of the present application is in the first state (+2D state); Figure 6 The MTF diagrams when the visual systems according to Embodiment 1, Embodiment 2 and Embodiment 3 of the present application are in the second state (-5D state) are shown; Figure 7 The left figure and the right figure in the figure respectively show the structural schematic diagrams of the visual system according to Example 4 of the present application when they are in the first state (+2D state) and the second state (-5D state); Figure 8 The left figure and the right figure in the figure respectively show the structural schematic diagrams of the visual system according to Example 5 of the present application when they are in the first state (+2D state) and the second state (-5D state); Fig. 9 The left figure and the right figure in the figure respectively show the structural schematic diagrams of the visual system according to Example 6 of the present application when they are in the first state (+2D state) and the second state (-5D state); Fig.10 shows the MTF diagram when the visual system according to Embodiment 4, Embodiment 5 and Embodiment 6 of the present application is in the first state (+2D state); Fig.11 shows the MTF diagram when the visual system according to Embodiment 4, Embodiment 5 and Embodiment 6 of the present application is in the second state (-5D state); Fig.12 The left figure and the right figure in the figure respectively show the structural schematic diagrams of the visual system according to Example 7 of the present application when they are in the first state (+2D state) and the second state (-5D state); Fig.13 The left figure and the right figure in the figure respectively show the structural schematic diagrams of the visual system according to Example 8 of the present application when they are in the first state (+2D state) and the second state (-5D state); Fig.14The left figure and the right figure in the figure respectively show the structural schematic diagrams of the visual system according to Example 9 of the present application when they are in the first state (+2D state) and the second state (-5D state); Fig.15 shows the MTF diagram when the visual system according to Embodiment 7, Embodiment 8 and Embodiment 9 of the present application is in the first state (+2D state); Fig.16 shows the MTF diagram when the visual system according to Embodiment 7, Embodiment 8 and Embodiment 9 of the present application is in the second state (-5D state); Fig.17 The figure shows the stray light situation of the system when the visual system according to the exemplary embodiment of the present application satisfies the conditional formula f23 / dbs=3.5 and (La+Lb) / ΔL=4.1; Fig.18 The figure shows the stray light situation of the system when the visual system according to the exemplary embodiment of the present application satisfies the conditional formula f23 / dbs=4.7 and (La+Lb) / ΔL=5.5; Fig.19 The figure shows the stray light situation of the system when the visual system according to the exemplary embodiment of the present application satisfies the conditional formula f23 / dbs=4.17 and (La+Lb) / ΔL=4.84. DETAILED DESCRIPTION

[0020] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application, and are not intended to 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.

[0021] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0022] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0023] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the convex position 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 concave position is not defined, it means that the lens surface is concave at least in the paraxial region.

[0024] It should also be understood that the terms "comprises", "including", "having", "includes" and / or "comprising", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0025] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0026] It should be noted that, in the absence of 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 methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can also be made without departing from the concept of the present application, 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 accompanying drawings and in conjunction with the embodiments.

[0027] The features, principles and other aspects of the present application are described in detail below.

[0028] The visual system according to the exemplary embodiment of the present application 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 from the first side to the second side along the optical axis; the first lens group and the second lens group may be arranged in sequence from the first side to the second side along the optical axis.

[0029] In an exemplary embodiment, the first lens group may be supported on or assembled to the first lens barrel; and the second lens group may be supported on or assembled to the second lens barrel.

[0030] 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 from the first side to the second side along the optical axis.

[0031] 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 at least partially conform to the second side surface of the first lens; the first side surface of the quarter wave plate may at least partially conform to the second side surface of the reflective polarizing element.

[0032] In an exemplary embodiment, the second lens group may include a second lens, a partially reflecting element, and a third lens. Exemplarily, the second lens, the partially reflecting element, and the third lens may be arranged in sequence from the first side to the second side along the optical axis.

[0033] In an exemplary embodiment, the second lens and the third lens may be cemented to form a cemented lens. Specifically, the second lens, the partial reflective element and the third lens may be cemented to form a cemented lens.

[0034] In an exemplary embodiment, the first lens may have positive optical power, its first side surface may be convex, and its second side surface may be flat.

[0035] In an exemplary embodiment, the second lens may have positive power, a first side surface thereof may be a convex surface, and a second side surface thereof may be a convex surface.

[0036] In an exemplary embodiment, the third lens may have negative power, and its first side surface may be a concave surface, and its second side surface may be a convex surface.

[0037] The light path can be folded back by rationally setting the structure of the visual system, which can effectively shorten the length of the visual system, reduce the volume and weight of the visual system, and make the visual system lighter. The setting of the cemented lens provides the system with a high-quality lens material with the advantages of lightness, good light transmittance, and wear resistance. It is more suitable for the lens manufacturing of VR equipment and can improve the quality and adaptability of the lens.

[0038] It can be understood that, in the direction along the optical axis, the surface of each element or structure in the visual system close to the first side and away from the second side can be the first side of the element or structure, and the surface of each element close to the second side and away from the first side can be the second side of the element or structure. The first side and the second side of the element or structure can be, for example, perpendicular to the optical axis.

[0039] In an exemplary embodiment, the first side may be, for example, a human eye side, and the second side may be, for example, a display side. The visual system may be used in, for example, a variety of VR devices or apparatuses.

[0040] In an exemplary embodiment, the distance on the optical axis of the first lens group (or the first lens group and the first lens barrel) relative to the display or image surface on the second side of the visual system can be fixed. The second lens group (or the second lens group and the second lens barrel) can be configured to be able to move along the optical axis to approach or move away from the display or image surface on the second side of the visual system, and enable the visual system to switch between the first state and the 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 surface, the distance between the second lens group and the first lens group on the optical axis is the largest, and the visual system can be in a +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 surface, the distance between the second lens group and the first lens group on the optical axis is the smallest, and the visual system can be in a -5D state, that is, the second state.

[0041] Exemplarily, when the visual system is in the first state, the diopter of the visual system is +2D, for example, it is applicable to users with a diopter of +2D; when the visual system is in the second state, the diopter of the visual system is -5D, for example, it is applicable to users with a diopter of -5D. Wherein, when the sign of the diopter is a negative sign, it may indicate that the user is a myopic user; when the sign of the diopter is a positive sign, it may indicate that the user is a hyperopic user; the specific value of the diopter may indicate the diopter of the user. For example, a diopter of +1D may indicate that the user's hyperopia is approximately 100 degrees, and a diopter of -1D may indicate that the user's myopia is approximately 100 degrees.

[0042] It should be understood that, in addition to the first state and the second state, the visual system according to the embodiment of the present application may also have other states, for example, between -5D and +2D. The visual system according to the embodiment of the present application can achieve continuous zooming within the range of -5D to +2D, which can meet the needs of users with different vision, so that users can enjoy the VR experience without wearing glasses.

[0043] In an exemplary embodiment, the visual system of the present application may include at least one aperture. The aperture may constrain the light path and control the light intensity. The aperture may be set at an appropriate position of the visual system as required, for example, the aperture may be located between the first side (e.g., the human eye side) and the first lens.

[0044] In an exemplary embodiment, the visual system has different virtual image distances VID in the first state and the second state, and the virtual image distance may 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 on the optical axis, wherein VID=1000 / diopter.

[0045] In an exemplary embodiment, the visual system of the present application may satisfy the conditional formula 3.93≤f23 / dbs≤4.30, wherein 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 surface of the second lens barrel. It can be understood that the first side end surface of the lens barrel may be the end surface or surface of the lens barrel that is closest to the first side and is perpendicular or approximately perpendicular to the optical axis; the second side end surface of the lens barrel may be the end surface or surface of the lens barrel that is closest to the second side and is perpendicular or approximately perpendicular to the optical axis.

[0046] In an exemplary embodiment, the visual system of the present application may satisfy the condition 4.55<(La+Lb) / ΔL<5.05, wherein 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 during the process of switching the visual system from the +2D state to the -5D state.

[0047] The visual system provided according to the 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, and 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, wherein 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 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 partial reflection 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 the second side surface is flat; the second lens has positive optical power, and its first side surface is convex, and the second side surface is convex; the third lens has negative optical power, and its first side surface is concave, and the second side surface is convex; and the second lens and the third lens are mutually bonded cemented lenses. 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 the visual system is switched between the first state and the second state. Through the above configuration of the visual system, 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 formula 3.93≤f23 / dbs≤4.30, the maximum distance La from the first side end face of the first lens barrel to the second side end face of the first lens barrel on the optical axis, the maximum distance Lb from the first side end face of the second lens barrel to the second side end face of the second lens barrel on the optical axis and the distance ΔL moved by the second lens group along the optical axis during the visual system switching from the first state to the second state meet the conditional formula 4.55<(La+Lb) / ΔL<5.05, the visual system can realize that the diopter can be adjusted from the +2D state to the -5D state, and it can also 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.

[0048] In an exemplary embodiment, the lens group and the lens barrel group of the visual system are configured as described above, and by setting the above two conditional expressions f23 / dbs and (La+Lb) / ΔL to satisfy different numerical ranges, the following three different visual system solutions can be formed: In the visual system 1 of the first scheme, the above two conditional expressions f23 / dbs and (La+Lb) / ΔL respectively satisfy f23 / dbs=3.5 and (La+Lb) / ΔL=4.1. It can be seen that the values ​​of the two conditional expressions are small, which 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 follows: Fig.17 As shown by Fig.17It can be seen that this scheme has a lot of stray light. For example, the side wall of the second lens barrel is prone to produce reflected stray light, and the intensity of stray light is relatively high, reaching 1.45E-3, which has a great impact on the imaging effect.

[0049] In the visual system 2 of the second scheme, 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 relatively large, which 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 the visual system 2 is shown in FIG. Fig.18 As shown by Fig.18 It can be seen that this solution also has a lot of stray light. For example, the side wall of the second lens barrel is prone to generate reflected stray light, and the intensity of the stray light is relatively high, reaching 2.172E-4, which has a greater impact on the imaging effect.

[0050] In the visual system 3 of the third scheme, 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 the visual system 3 is shown in FIG. Fig.19 As shown by Fig.19 It can be seen that this solution has less system stray light, which can effectively reduce the stray light interference generated at locations such as the side wall of the second lens barrel. The stray light intensity is also significantly reduced to 8.086E-5, which has little impact on the imaging effect of the system and is beneficial to improving the clarity of the image.

[0051] Therefore, according to the visual system of the present application, by reasonably configuring the system and controlling the conditions 3.93≤f23 / dbs≤4.30 and 4.55<(La+Lb) / ΔL<5.05, the visual system can realize the adjustment of the refractive power from the +2D state to the -5D state, and at the same time, it can 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 clarity of the imaging and ensuring that users can obtain clear images under different visual needs.

[0052] 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 prevent the problem of excessive light incidence and serious stray light ghosts when it exceeds the upper limit value, and can also prevent the problem of blocking effective light when it is less than the lower limit value.

[0053] 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 prevent the problem of increasing the thickness of the whole machine and affecting the user experience when it exceeds the upper limit value, and can also prevent the problem of affecting the mechanical strength of the first lens barrel when it is 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 thickness of the whole machine.

[0054] 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 effect of attaching them to the surface of the first lens and reduce the generation of bubbles, wrinkles, orange peel, etc., but also prevent them from being too thick, resulting in the problem that the light reflection position of the actual module deviates from the theoretical design position, thus causing the performance of the whole machine to decline.

[0055] 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 prevent the problem of increasing the shape of the module and affecting the volume of the whole machine when it exceeds the upper limit value, and can also prevent the problem of insufficient strength of the second lens barrel and affecting the mechanical performance of the module when it is 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.

[0056] 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 the excess light from entering due to exceeding the upper limit value, resulting in serious stray light ghosts, but also prevent the problem of blocking the effective light when it is less than the lower limit value; thus, while not blocking the effective light, it can avoid the excess light, which is beneficial to ensuring the imaging effect and avoiding serious stray light ghosts.

[0057] 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 problem that the extension length of the module is 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 the gear subdivision of the system from +2D to -5D cannot be accurately controlled 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.

[0058] 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 of the second lens barrel 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 restricted 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.

[0059] 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 increase of the module's shape and affecting 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.

[0060] 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 barrel. By reasonably controlling the range of this conditional formula, it can not only prevent it from being less than the lower limit value, resulting in an increase in the outer shape of the module and affecting the volume of the whole machine, but also prevent it from exceeding the upper limit value, resulting in insufficient strength of the first barrel and affecting the mechanical performance of the module; thus, it can achieve both ensuring the miniaturization of the system and ensuring the strength of the first barrel and the mechanical performance of the module.

[0061] 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 barrel, das is the inner diameter of the first side end surface of the first barrel, and La is the maximum distance on the optical axis from the first side end surface of the first barrel to the second side end surface of the first barrel. By reasonably controlling the range of this conditional formula, it can not only prevent it from exceeding the upper limit value, resulting in too large a wall thickness of the first barrel and making its processing and forming too difficult, but also prevent it from being less than the lower limit value, resulting in insufficient strength of the first barrel and affecting the mechanical performance of the module; thus, it is beneficial for the first barrel to be designed more reasonably, both meeting the strength requirements to ensure the mechanical performance of the module and having good processing and forming performance.

[0062] 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 barrel to the second side end surface of the second 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 it from exceeding the upper limit value and increasing the thickness of the whole machine, affecting the user experience, but also prevent it from being less than the lower limit value and affecting the mechanical strength of the second barrel; thus, it can achieve the miniaturization of the system while ensuring the mechanical strength of the second barrel and the mechanical performance of the module.

[0063] 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 barrel, dbm is the inner diameter of the second side end surface of the second 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 not only prevent it from exceeding the upper limit value, resulting in too large a wall thickness of the second barrel and making its processing and forming too difficult, but also prevent it from being less than the lower limit value, resulting in too small an assembly suction surface and bearing surface of the second barrel and affecting the assembly of the barrel and the module; thus, it can ensure both the processing and forming performance and the assembly performance of the second barrel.

[0064] 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, the sudden change in the outer shape of the diopter adjustment component of the module can be avoided, and the excessive processing and forming difficulty can be avoided.

[0065] 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 lens has better curvature radius characteristics and has the advantages of improving distortion aberration and astigmatism aberration. After using the aspherical lens, the aberration that appears during imaging can be eliminated as much as possible, thereby improving the imaging quality.

[0066] 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.

[0067] On the one hand, according to the visual system of the exemplary embodiment of the present application, a first lens barrel and a second lens barrel are 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 are arranged in sequence from the first side to the second side along the optical axis, and the first lens group is arranged to bear on the first lens barrel, and the second lens group is arranged to bear on the second lens barrel; and the first lens group is further arranged 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 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, wherein the first lens has positive optical power, and its first side surface is convex, and the second side surface is flat; the second lens has positive optical power, and its first side surface is convex, and the second side surface is convex; the third lens has negative optical power, and its first side surface is concave, and the second side surface is convex; and the second lens and the third lens are cemented lenses cemented to each other; and the second lens is configured The lens group can move 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 the first state and the second state; at the same time, 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 are controlled to satisfy the condition 3.93≤f23 / dbs≤4.30, the maximum distance La from the first side end face of the first lens barrel to the second side end face of the first lens barrel on the optical axis, the maximum distance Lb from the first side end face of the second lens barrel to the second side end face of the second lens barrel on the optical axis and the distance ΔL moved by the second lens group along the optical axis during the switching of the visual system from the first state to the second state meet the condition 4.55<(La+Lb) / ΔL<5.05, which can enable the visual system to adjust the refractive power from the +2D state to the -5D state, and can also 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 needs.

[0068] 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 partial reflection 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 a 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 users can obtain clear images under different visual requirements.

[0069] The visual system according to the exemplary embodiments of the present application adopts, for example, a three-mirror catadioptric architecture. By reasonably setting system structures such as lens barrels and lens groups, 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, through the movement of the second lens group, zooming within the range of -5D to +2D can be achieved to meet the needs of users with different visual acuities, and users can enjoy the VR experience without wearing glasses; at the same time, it can also effectively reduce the stray light interference generated at positions such as the side wall of the second lens barrel, which is beneficial to improving the imaging quality and ensuring that users can obtain clear images under different visual requirements; in addition, the use of cemented lenses in the system has the advantages of being lightweight, having good light transmittance, and being wear-resistant, and is more suitable for the manufacture of lenses for VR devices, improving the quality and adaptability of the lenses.

[0070] In addition, the present application also provides a VR device, which may include the visual system provided by any of the above-mentioned embodiments, wherein the first side may be the human eye side, and the second side may be the display / image surface side. The VR device can achieve continuous zoom in the range of -5D to +2D, allowing users with different vision conditions to clearly enjoy the VR experience without wearing glasses, and at the same time has the characteristics of miniaturization, light weight, high imaging quality and stable performance, thereby improving the user experience.

[0071] Specific embodiments of the visual system applicable to the above-mentioned embodiments are further described below with reference to the accompanying drawings.

[0072] Example 1

[0073] The following reference Figure 2 Describe the visual system according to Example 1 of the present application. Figure 2 The middle left figure shows a schematic diagram of the structure of the visual system according to Example 1 of the present application when it is in the first state (+2D state). Figure 2 The middle right figure shows a schematic diagram of the structure of the visual system according to Example 1 of the present application when it is in the second state (-5D state).

[0074] like Figure 2 As shown, the visual system includes a first lens barrel Pa and a second lens barrel Pb, which are arranged in sequence from the first side to the second side along the optical axis. The visual system also includes a first lens group supported by the first lens barrel Pa and a second lens group supported by the second lens barrel Pb, wherein the first lens group includes a first lens E1, a reflective polarizing element RP and a quarter-wave plate QWP arranged in sequence from the first side to the second side along the optical axis, 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 from the first side to the second side along the optical axis.

[0075] In this embodiment, the first lens E1 has positive power, its first side surface S3 is convex, and its second side surface S4 is flat; the second lens E2 has positive power, its first side surface S13 is convex, and its second side surface S14 is convex; the third lens E3 has negative power, its first side surface S14 is concave, and its second side surface S15 is convex. The reflective polarizing element RP is disposed on the second side surface of the first lens E1, and the quarter wave plate QWP is disposed on the second side surface of the reflective polarizing element RP. The second lens E2 and the third lens E3 are cemented lenses that are cemented to each other.

[0076] In this embodiment, the first side may be, for example, the human eye side, and the second side may be, for example, the display side. A display / image surface 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 surface IMG along the optical axis; 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 to approach or move away from the display / image surface IMG, and in this process the visual system can achieve zooming in the range of -5D to +2D. Figure 2 The middle left figure shows a schematic diagram of the structure 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 surface IMG. At this time, the visual system is in the +2D state. Figure 2 The middle right figure shows a schematic diagram of the structure of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the farthest position from the display / image surface IMG. At this time, the visual system is in a -5D state.

[0077] Table 1 shows the basic parameters of the visual system of Example 1, wherein the units of the radius of curvature and thickness / distance are both millimeters (mm).

[0078] Table 1

[0079] The parameters D1 to D5 in Table 1 can be understood as follows: D5 can be understood as the value taken along the optical axis from the first side of the filter and / or protective glass IR / CG arranged 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 taken 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 taken 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 taken along the optical axis from the first side of the second lens E2 to the second side of the quarter-wave plate QWP; D1 can be understood as the value of the virtual image distance of the visual system according to this embodiment. In the process of realizing 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 change accordingly. The visual system is Figure 2 The +2D state shown in the middle left figure and Figure 2 The values ​​of parameters D1 to D5 in the -5D state shown in the middle right figure are shown in Table 2 below.

[0080] Table 2

[0081] In Example 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, and the surface shape of each aspherical surface can be defined by but not limited to the following aspherical surface formula: (1) in, The aspheric surface is at a height of h When the position is , the distance vector height from the vertex of the aspherical surface; c is the paraxial curvature of the aspheric surface, c =1 / R (i.e., paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the cone coefficient; Ai Aspheric i Table 3 below gives the high-order coefficients that can be used for each aspheric surface S3 and S13-S15 in Example 1: A 4 , A 6 , A 8 , A 10 , A 12 , A 14 , A 16 , A 18 and A 20 .

[0082] Table 3

[0083] Referring to Table 10, according to the visual system of this embodiment, the values ​​of its multiple structural parameters are respectively shown in the column of 'Example 1' in Table 10, wherein 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 of the first lens barrel Pa to its second side end face on the optical axis, and Lb is the maximum distance from the first side end face of the second lens barrel Pb to its second side end face on the optical axis. According to the visual system of this embodiment, the values ​​of the above structural parameters correspond to each other in the two different focal length states of +2D and -5D. The units of the above parameters shown in Table 10 are all millimeters (mm), and the schematic diagram of the above parameters in the visual system structure diagram can be referred to Figure 1 .

[0084] Example 2

[0085] The following reference Figure 3 Describe the visual system according to Example 2 of the present application.

[0086] like Figure 3 As shown, similar to the visual system in Example 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 from the first side to the second side along the optical axis, and also includes a first lens group supported by the first lens barrel Pa and a second lens group supported by the second lens barrel Pb, wherein the first lens group includes a first lens E1, a reflective polarizing element RP and a quarter-wave plate QWP, which are arranged in sequence from the first side to the second side along the optical axis, 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, which are arranged in sequence from the first side to the second side along the optical axis.

[0087] Similar to Embodiment 1, in this embodiment, the first side may be, for example, the human eye side, and the second side may be, for example, the display side. A display / image surface 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 surface IMG along the optical axis; 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 to approach or move away from the display / image surface IMG, and in this process the visual system can achieve zooming in the range of -5D to +2D. Figure 3The middle left figure shows a schematic diagram of the structure 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 surface IMG. At this time, the visual system is in the first state (+2D state). Figure 3 The middle right figure shows a schematic diagram of the structure of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the farthest position from the display / image surface IMG. At this time, the visual system is in the second state (-5D state).

[0088] The basic parameter table of the visual system of this embodiment is the same as Table 1 in Example 1, the numerical values ​​of parameters D1 to D5 are the same as Table 2 in Example 1, and the high-order coefficient table of the aspherical mirror surface is the same as Table 3 in Example 1.

[0089] The values ​​of the structural parameters of the visual system of this embodiment are shown in the 'Example 2' column in Table 10. 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.

[0090] Example 3

[0091] The following reference Figure 4 Describe the visual system according to Example 3 of the present application.

[0092] like Figure 4 As shown, similar to the visual system in Example 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 from the first side to the second side along the optical axis, and also includes a first lens group supported by the first lens barrel Pa and a second lens group supported by the second lens barrel Pb, wherein the first lens group includes a first lens E1, a reflective polarizing element RP and a quarter-wave plate QWP, which are arranged in sequence from the first side to the second side along the optical axis, 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, which are arranged in sequence from the first side to the second side along the optical axis.

[0093] Similar to Embodiment 1, in this embodiment, the first side may be, for example, the human eye side, and the second side may be, for example, the display side. A display / image surface 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 surface IMG along the optical axis; 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 to approach or move away from the display / image surface IMG, and in this process the visual system can achieve zooming in the range of -5D to +2D. Figure 4The middle left figure shows a schematic diagram of the structure 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 surface IMG. At this time, the visual system is in the first state (+2D state). Figure 4 The middle right figure shows a schematic diagram of the structure of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the farthest position from the display / image surface IMG. At this time, the visual system is in the second state (-5D state).

[0094] The basic parameter table of the visual system of this embodiment is also the same as Table 1 in Example 1, the values ​​of parameters D1 to D5 are also the same as Table 2 in Example 1, and the high-order coefficient table of the aspheric mirror surface is also the same as Table 3 in Example 1.

[0095] The values ​​of the structural parameters of the visual system of this embodiment are shown in the 'Example 3' column in Table 10. 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.

[0096] Figure 5 The MTF curves of the visual systems of Embodiment 1, Embodiment 2 and Embodiment 3 when they are in the +2D state are shown. Figure 6 The MTF curves of the visual systems of Example 1, Example 2 and Example 3 when they are in the -5D state are shown. The MTF (Modulation Transfer Function) curve can represent the optical modulation function values ​​corresponding to different spatial frequencies. Figure 5 and Figure 6 It can be seen that the visual systems provided in Example 1, Example 2 and Example 3 can achieve good imaging quality in two different focal length states of +2D and -5D.

[0097] Example 4

[0098] The following reference Figure 7 Describe the visual system according to Example 4 of the present application. Figure 7 The middle left figure shows a schematic diagram of the structure of the visual system according to Example 4 of the present application when it is in the first state (+2D state). Figure 7 The middle right figure shows a schematic diagram of the structure of the visual system according to Example 4 of the present application when it is in the second state (-5D state).

[0099] like Figure 7As shown, the visual system includes a first lens barrel Pa and a second lens barrel Pb, which are arranged in sequence from the first side to the second side along the optical axis. The visual system also includes a first lens group supported by the first lens barrel Pa and a second lens group supported by the second lens barrel Pb, wherein the first lens group includes a first lens E1, a reflective polarizing element RP and a quarter-wave plate QWP arranged in sequence from the first side to the second side along the optical axis, 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 from the first side to the second side along the optical axis.

[0100] In this embodiment, the first lens E1 has positive power, its first side surface S3 is convex, and its second side surface S4 is flat; the second lens E2 has positive power, its first side surface S13 is convex, and its second side surface S14 is convex; the third lens E3 has negative power, its first side surface S14 is concave, and its second side surface S15 is convex. The reflective polarizing element RP is disposed on the second side surface of the first lens E1, and the quarter wave plate QWP is disposed on the second side surface of the reflective polarizing element RP. The second lens E2 and the third lens E3 are cemented lenses that are cemented to each other.

[0101] In this embodiment, the first side may be, for example, the human eye side, and the second side may be, for example, the display side. A display / image surface 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 surface IMG along the optical axis; 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 to approach or move away from the display / image surface IMG, and in this process the visual system can achieve zooming in the range of -5D to +2D. Figure 7 The middle left figure shows a schematic diagram of the structure 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 surface IMG. At this time, the visual system is in the +2D state. Figure 7 The middle right figure shows a schematic diagram of the structure of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the farthest position from the display / image surface IMG. At this time, the visual system is in a -5D state.

[0102] Table 4 shows the basic parameters of the visual system of Example 4, wherein the units of the radius of curvature and thickness / distance are both millimeters (mm).

[0103] Table 4

[0104] 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.

[0105] Table 5

[0106] 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.

[0107] Table 6

[0108] 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.

[0109] Example 5

[0110] The following reference Figure 8 Describe the visual system according to Example 5 of the present application.

[0111] like Figure 8As shown, similar to the visual system in Example 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 from the first side to the second side along the optical axis, and also includes a first lens group supported by the first lens barrel Pa and a second lens group supported by the second lens barrel Pb, wherein the first lens group includes a first lens E1, a reflective polarizing element RP and a quarter-wave plate QWP, which are arranged in sequence from the first side to the second side along the optical axis, 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, which are arranged in sequence from the first side to the second side along the optical axis.

[0112] Similar to Embodiment 4, in this embodiment, the first side may be, for example, the human eye side, and the second side may be, for example, the display side. A display / image surface 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 surface IMG along the optical axis; 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 to approach or move away from the display / image surface IMG, and in this process the visual system can achieve zooming in the range of -5D to +2D. Figure 8 The middle left figure shows a schematic diagram of the structure 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 surface IMG. At this time, the visual system is in the first state (+2D state). Figure 8 The middle right figure shows a schematic diagram of the structure of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the farthest position from the display / image surface 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 4 in Example 4, the numerical values ​​of parameters D1 to D5 are the same as Table 5 in Example 4, and the high-order coefficient table of the aspheric mirror surface is the same as Table 6 in Example 4.

[0114] The values ​​of the structural parameters of the visual system of this embodiment are shown in the 'Example 5' column in Table 10. 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.

[0115] Example 6

[0116] The following reference Fig. 9 Describe the visual system according to Example 6 of the present application.

[0117] like Fig. 9As shown, similar to the visual system in Example 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 from the first side to the second side along the optical axis, and also includes a first lens group supported by the first lens barrel Pa and a second lens group supported by the second lens barrel Pb, wherein the first lens group includes a first lens E1, a reflective polarizing element RP and a quarter-wave plate QWP, which are arranged in sequence from the first side to the second side along the optical axis, 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, which are arranged in sequence from the first side to the second side along the optical axis.

[0118] Similar to Embodiment 4, in this embodiment, the first side may be, for example, the human eye side, and the second side may be, for example, the display side. A display / image surface 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 surface IMG along the optical axis; 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 to approach or move away from the display / image surface IMG, and in this process the visual system can achieve zooming in the range of -5D to +2D. Fig. 9 The middle left figure shows a schematic diagram of the structure 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 surface IMG. At this time, the visual system is in the first state (+2D state). Fig. 9 The middle right figure shows a schematic diagram of the structure of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the farthest position from the display / image surface IMG. At this time, the visual system is in the second state (-5D state).

[0119] The basic parameter table of the visual system of this embodiment is also the same as Table 4 in Example 4, the values ​​of parameters D1 to D5 are also the same as Table 5 in Example 4, and the high-order coefficient table of the aspheric mirror surface is also the same as Table 6 in Example 4.

[0120] The values ​​of the structural parameters of the visual system of this embodiment are shown in the 'Example 6' column in Table 10. 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.

[0121] Fig.10 The MTF curves of the visual systems of Embodiment 4, Embodiment 5 and Embodiment 6 when they are in the +2D state are shown. Fig.11 The MTF curves of the visual systems of Embodiments 4, 5 and 6 when they are in the -5D state are shown. Fig.10 and Fig.11It can be seen that the visual systems provided in Example 4, Example 5 and Example 6 can achieve good imaging quality in two different focal length states of +2D and -5D.

[0122] Example 7

[0123] The following reference Fig.12 Describe the visual system according to Example 7 of the present application. Fig.12 The middle left figure shows a schematic diagram of the structure of the visual system according to Example 7 of the present application when it is in the first state (+2D state). Fig.12 The middle right figure shows a schematic diagram of the structure of the visual system according to Example 7 of the present application when it is in the second state (-5D state).

[0124] like Fig.12 As shown, the visual system includes a first lens barrel Pa and a second lens barrel Pb, which are arranged in sequence from the first side to the second side along the optical axis. The visual system also includes a first lens group supported by the first lens barrel Pa and a second lens group supported by the second lens barrel Pb, wherein the first lens group includes a first lens E1, a reflective polarizing element RP and a quarter-wave plate QWP arranged in sequence from the first side to the second side along the optical axis, 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 from the first side to the second side along the optical axis.

[0125] In this embodiment, the first lens E1 has positive power, its first side surface S3 is convex, and its second side surface S4 is flat; the second lens E2 has positive power, its first side surface S13 is convex, and its second side surface S14 is convex; the third lens E3 has negative power, its first side surface S14 is concave, and its second side surface S15 is convex. The reflective polarizing element RP is disposed on the second side surface of the first lens E1, and the quarter wave plate QWP is disposed on the second side surface 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 may be, for example, the human eye side, and the second side may be, for example, the display side. A display / image surface 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 surface IMG along the optical axis; 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 to approach or move away from the display / image surface IMG, and in this process the visual system can achieve zooming in the range of -5D to +2D. Fig.12The middle left figure shows a schematic diagram of the structure 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 surface IMG. At this time, the visual system is in the +2D state. Fig.12 The middle right figure shows a schematic diagram of the structure of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the farthest position from the display / image surface IMG. At this time, the visual system is in a -5D state.

[0127] Table 7 shows the basic parameters of the visual system of Example 7, wherein the units of the radius of curvature and thickness / distance are both millimeters (mm).

[0128] Table 7

[0129] 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 7 are respectively shown in Table 8 below. The meanings of the parameters D1 to D5 can refer to the description in Example 1.

[0130] Table 8

[0131] 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 high-order 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 , wherein the surface shape of each aspheric surface can be defined by the formula (1) given in the above embodiment 1.

[0132] Table 9

[0133] Referring to Table 10, the values ​​of the structural parameters of the visual system of this embodiment are respectively shown in the 'Example 7' 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.

[0134] Example 8

[0135] The following reference Fig.13 Describe the visual system according to Example 8 of the present application.

[0136] like Fig.13 As shown, similar to the visual system in Example 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 from the first side to the second side along the optical axis, and also includes a first lens group supported by the first lens barrel Pa and a second lens group supported by the second lens barrel Pb, wherein the first lens group includes a first lens E1, a reflective polarizing element RP and a quarter-wave plate QWP arranged in sequence from the first side to the second side along the optical axis, 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 from the first side to the second side along the optical axis.

[0137] Similar to Example 7, in this embodiment, the first side may be, for example, the human eye side, and the second side may be, for example, the display side. A display / image surface 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 surface IMG along the optical axis; 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 to approach or move away from the display / image surface IMG, and in this process the visual system can achieve zooming in the range of -5D to +2D. Fig.13 The middle left figure shows a schematic diagram of the structure 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 surface IMG. At this time, the visual system is in the first state (+2D state). Fig.13 The middle right figure shows a schematic diagram of the structure of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the farthest position from the display / image surface IMG. At this time, the visual system is in the second state (-5D state).

[0138] The basic parameter table of the visual system of this embodiment is the same as Table 7 in Example 7, the numerical values ​​of parameters D1 to D5 are the same as Table 8 in Example 7, and the high-order coefficient table of the aspheric mirror surface is the same as Table 9 in Example 7.

[0139] The values ​​of the structural parameters of the visual system of this embodiment are shown in the 'Example 8' column in Table 10. 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.

[0140] Example 9

[0141] The following reference Fig.14 Describe the visual system according to Example 9 of the present application.

[0142] like Fig.14 As shown, similar to the visual system in Example 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 from the first side to the second side along the optical axis, and also includes a first lens group supported by the first lens barrel Pa and a second lens group supported by the second lens barrel Pb, wherein the first lens group includes a first lens E1, a reflective polarizing element RP and a quarter-wave plate QWP arranged in sequence from the first side to the second side along the optical axis, 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 from the first side to the second side along the optical axis.

[0143] Similar to Example 7, in this embodiment, the first side may be, for example, the human eye side, and the second side may be, for example, the display side. A display / image surface 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 surface IMG along the optical axis; 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 to approach or move away from the display / image surface IMG, and in this process the visual system can achieve zooming in the range of -5D to +2D. Fig.14 The middle left figure shows a schematic diagram of the structure 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 surface IMG. At this time, the visual system is in the first state (+2D state). Fig.14 The middle right figure shows a schematic diagram of the structure of the visual system when the second lens group and the second lens barrel Pb move along the optical axis to the farthest position from the display / image surface IMG. At this time, the visual system is in the second state (-5D state).

[0144] The basic parameter table of the visual system of this embodiment is also the same as Table 7 in Example 7, the numerical values ​​of parameters D1 to D5 are also the same as Table 8 in Example 7, and the high-order coefficient table of the aspheric mirror surface is also the same as Table 9 in Example 7.

[0145] The values ​​of the structural parameters of the visual system of this embodiment are shown in the 'Example 9' column in Table 10. 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.

[0146] Fig.15 The MTF curves of the visual systems of Embodiment 7, Embodiment 8 and Embodiment 9 when they are in the +2D state are shown. Fig.16The MTF curves of the visual systems of Example 7, Example 8 and Example 9 when they are in the -5D state are shown. Fig.15 and Fig.16 It can be seen that the visual systems provided in Examples 7, 8 and 9 can achieve good imaging quality in two different focal length states of +2D and -5D.

[0147] Table 10

[0148] In addition, in Examples 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 when the visual system switches from the +2D state to the -5D state, and the change Δf of the effective focal length of the system when the visual system switches from the +2D state to the -5D state are respectively shown in Table 11 below.

[0149] Table 11

[0150] And, Examples 1 to 9 respectively satisfy the conditions shown in Table 12 below. The visual systems of each embodiment in Examples 1 to 9 correspond to the same values ​​of the conditional expressions in Table 12 below in two different focal length states of +2D and -5D.

[0151] Table 12

[0152] The present application also provides an imaging device, which is provided with an electronic photosensitive element for imaging, and the electronic photosensitive element can be a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The imaging device can be an independent imaging device such as a digital camera, or an imaging module integrated in a mobile electronic device such as a mobile phone. The imaging device is equipped with the visual system described above.

[0153] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of protection involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but 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 above features are replaced with the technical features with similar functions disclosed in the present application (but not limited to) to form a technical solution.

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; 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: 3.7mm<|f2 / f3|×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