Visual system

Abstract

The utility model provides a visual system. The visual system comprises a first lens cone, a second lens cone, a first optical element group supported in the first lens cone, and a second optical element group supported in the second lens cone. The second optical element group is configured to be capable of moving along the optical axis so that the visual system can be switched between the first state and the second state. The effective focal length f3 of the third lens, the inner diameter dbs of the first side end face of the second lens barrel and the inner diameter dbm of the second side end face of the second lens barrel meet the following condition: 0.5 < f3 / (dbs + dbm) < 1.9; the maximum distance Lb between the first side end face of the second lens cone and the second side end face of the second lens cone on the optical axis and the distance delta L of the second optical element group moving along the optical axis when the visual system is switched between the first state and the second state meet the following condition: 1.16 < = Lb / delta L < = 3.10. According to the utility model, the problem of poor field curvature performance of a visual system in the prior art is solved.

Description

Technical Field

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

[0002] With the further popularization of AR / VR (Augmented Reality / Virtual Reality) devices, users are paying more and more attention to AR / VR devices. At the same time, they are putting forward higher requirements for the thinness, image quality and wearing experience of AR / VR devices. Traditional AR / VR devices based on aspherical and Fresnel technology are very thick and heavy, which can no longer meet the needs of consumers. With the introduction of the foldable solution, the problem of making AR / VR devices thinner and lighter has been greatly improved, meeting consumers' requirements for thinner and lighter devices.

[0003] However, while existing folded optical path-based reflex optical designs excel in shortening lens length, there is still room for improvement in optical performance. For example, poor lens assembly stability leads to deterioration of surface curvature, affecting image quality and requiring urgent improvement. Furthermore, among AR / VR users, visual acuity varies significantly, with many being nearsighted or farsighted, and the degree of nearsightedness or farsightedness differs among individuals. Using a fixed-focal-length reflex module results in inconsistent image quality, leading to a poor user experience for some. Therefore, it is necessary to design and develop a diopter-adjustable visual system to enable users with varying vision to see images clearly without glasses, thereby enhancing the VR visual experience. Utility Model Content

[0004] The main objective of this invention is to provide a visual system to solve the problem of poor field curvature performance in existing visual systems.

[0005] To achieve the above objectives, according to one aspect of the present invention, a visual system is provided, comprising a lens barrel assembly and an optical element assembly. The optical element assembly comprises only three lenses with optical power. The lens barrel assembly includes a first lens barrel and a second lens barrel arranged sequentially from a first side to a second side along the optical axis. The optical element assembly includes a first optical element assembly and a second optical element assembly, the first optical element assembly resting within the first lens barrel and the second optical element assembly resting within the second lens barrel. The first optical element assembly includes a first lens, a reflective polarizing element, a quarter-wave plate, and a second lens arranged sequentially from a first side to a second side along the optical axis. The second optical element assembly includes a third lens and a partially reflective element arranged sequentially from a first side to a second side along the optical axis. The first lens has positive optical power. The first side is convex, the second lens has optical power, the third lens has positive optical power, and the second side of the third lens is convex; the second optical element group is configured to move along the optical axis to approach or move away from the display located on the second side, so that the visual system switches between the first state and the second state; the effective focal length f3 of the third lens, the inner diameter dbs of the first side end face of the second lens barrel, and the inner diameter dbm of the second side end face of the second lens barrel satisfy: 0.5 < f3 / (dbs+dbm) < 1.9; the maximum distance Lb from the first side end face to the second side end face of the second lens barrel on the optical axis, and the distance ΔL that the second optical element group moves along the optical axis when the visual system switches between the first state and the second state satisfy: 1.16 ≤ Lb / ΔL ≤ 3.10.

[0006] According to another aspect of this utility model, a visual system is provided, comprising a lens barrel assembly and an optical element assembly. The optical element assembly includes only three lenses with optical power. The lens barrel assembly includes a first lens barrel and a second lens barrel arranged sequentially from a first side to a second side along the optical axis. The optical element assembly includes a first optical element assembly and a second optical element assembly, with the first optical element assembly resting inside the first lens barrel and the second optical element assembly resting inside the second lens barrel. The first optical element assembly includes a first lens, a reflective polarizing element, a quarter-wave plate, and a second lens arranged sequentially from a first side to a second side along the optical axis. The second optical element assembly includes a third lens and a partially reflective element arranged sequentially from a first side to a second side along the optical axis. The first lens has positive optical power, and its first side surface is convex. The second lens has optical power, the third lens has positive optical power, and the second side of the third lens is convex. The second optical element group is configured to move along the optical axis to approach or move away from the display located on the second side, so that the visual system switches between the first state and the second state. The effective focal length f3 of the third lens, the inner diameter dbs of the first side end face of the second lens barrel, and the inner diameter dbm of the second side end face of the second lens barrel satisfy the following: 0.5 < f3 / (dbs+dbm) < 1.9. The inner diameter das of the first side end face of the first lens barrel, the inner diameter dam of the second side end face of the first lens barrel, and the distance ΔL that the second optical element group moves along the optical axis when the visual system switches between the first state and the second state satisfy the following: 2.68 ≤ (dam-das) / ΔL ≤ 5.77.

[0007] Furthermore, 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, the center thickness CTQ of the quarter-wave plate on the optical axis, the center thickness CT2 of the second lens on the optical axis, and the maximum distance La between the first side end face and the second side end face of the first lens barrel satisfy the following condition: 0.95 < (CT1 + CTR + CTQ + CT2) / La < 1.45.

[0008] Furthermore, the central thickness CT1 of the first lens on the optical axis and the inner diameter das of the first side end face of the first lens barrel satisfy the following condition: 7.20≤das / CT1≤10.86.

[0009] Furthermore, the difference Δf between the effective focal length of the visual system in the first state and the effective focal length of the visual system in the second state, the inner diameter dbs of the first side end face of the second lens barrel, and the inner diameter dam of the second side end face of the first lens barrel satisfy the following condition: 0.15 < Δf / (dbs-dam) < 2.7.

[0010] Furthermore, the center thickness CT3 of the third lens, the outer diameter Dbs of the first side end face of the second lens barrel, and the outer diameter Dbm of the second side end face of the second lens barrel satisfy the following condition: 1.37≤CT3 / (Dbs-Dbm)≤4.29.

[0011] Furthermore, the effective focal length f1 of the first lens, the effective focal length f2 of the second lens, and the maximum distance La between the first side end face and the second side end face of the first lens barrel satisfy the following condition: 1.57mm≤|f1 / f2|×La≤8.78mm.

[0012] Furthermore, the outer diameter Das of the first side end face of the first lens barrel, the outer diameter Dam of the second side end face of the first lens barrel, and the combined focal length fz of the first lens, the reflective polarizing element, the quarter-wave plate, and the second lens satisfy the following condition: 0.12≤(Das+Dam) / fz≤1.25.

[0013] Furthermore, the radius of curvature R1 of the first side surface of the first lens and the inner diameter das of the first side end face of the first lens barrel satisfy the following condition: 1.5 < R1 / das < 1.8.

[0014] Furthermore, the radius of curvature R6 of the second side surface of the third lens and the outer diameter Dbm of the second end face of the second lens barrel satisfy the following condition: -2.20≤R6 / Dbm≤-1.39.

[0015] Furthermore, the radius of curvature R5 of the first side surface of the third lens, the radius of curvature R4 of the second side surface of the second lens, and the maximum distance La between the first end face of the first lens barrel and the second end face of the first lens barrel satisfy the following condition: 1.67mm≤|R5 / R4|×La≤14.59mm.

[0016] Furthermore, the inner diameter das of the first side end face of the first lens barrel, the inner diameter dam of the second side end face of the first lens barrel, and the distance ΔL that the second optical element group moves along the optical axis when the visual system switches between the first state and the second state satisfy the following condition: 2.68≤(dam-das) / ΔL≤5.77.

[0017] Furthermore, the difference Δf between the effective focal length of the visual system in the first state and the effective focal length of the visual system in the second state, the outer diameter Dbs of the first side end face of the second lens barrel, and the inner diameter dbm of the second side end face of the second lens barrel satisfy the following condition: 2.10≤(Dbs-dbm) / Δf≤11.45.

[0018] Furthermore, the effective focal length f3 of the third lens, the Abbe number V3 of the third lens, and the maximum distance Lb on the optical axis from the first side end face to the second side end face of the second lens barrel satisfy the following condition: 1.15 < Lb / (f3 / V3) < 2.5.

[0019] Furthermore, the maximum distance La between the first side end face and the second side end face of the first lens tube, and the outer diameter Dam of the second side end face of the first lens tube satisfy the following condition: 4.76≤Dam / La≤8.83.

[0020] Furthermore, the maximum distance Lb between the first side end face and the second side end face of the second lens tube on the optical axis and the outer diameter Dbs of the first side end face of the second lens tube satisfy the following condition: 12.04≤Dbs / Lb≤14.25.

[0021] The visual system, applying the technical solution of this utility model, includes a lens barrel assembly and an optical element assembly. The optical element assembly includes only three lenses with optical power. The lens barrel assembly includes a first lens barrel and a second lens barrel arranged sequentially from the first side to the second side along the optical axis. The optical element assembly includes a first optical element assembly and a second optical element assembly. The first optical element assembly rests within the first lens barrel, and the second optical element assembly rests within the second lens barrel. The first optical element assembly includes a first lens, a reflective polarizing element, a quarter-wave plate, and a second lens arranged sequentially from the first side to the second side along the optical axis. The second optical element assembly includes a third lens and a partially reflective element arranged sequentially from the first side to the second side along the optical axis. The first lens has positive optical power, and its first side surface is convex. The second lens has optical power, the third lens has positive optical power, and the second side of the third lens is convex. The second optical element group is configured to move along the optical axis to approach or move away from the display located on the second side, so that the visual system switches between the first state and the second state. The effective focal length f3 of the third lens, the inner diameter dbs of the first side end face of the second lens barrel, and the inner diameter dbm of the second side end face of the second lens barrel satisfy the following condition: 0.5 < f3 / (dbs+dbm) < 1.9. 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 that the second optical element group moves along the optical axis when the visual system switches between the first state and the second state satisfy the following condition: 1.16 ≤ Lb / ΔL ≤ 3.10.

[0022] The visual system in this application consists of two lens barrels, three lenses, a reflective polarizing element, a quarter-wave plate, and some reflective elements. By rationally configuring the visual system to satisfy the condition 0.5 < f3 / (dbs+dbm) < 1.9, the inner diameter of the second lens barrel and the thickness of the third lens are limited. Simultaneously, the second lens barrel lacks other structures that support the third lens, easily leading to poor assembly stability of the third lens, resulting in poor field curvature and affecting image quality. To solve the field curvature problem caused by satisfying 0.5 < f3 / (dbs+dbm) < 1.9, this application controls Lb / ΔL within a reasonable range, ensuring a longer second lens barrel. This increases the bearing area between the second lens barrel and the outer ring surface of the third lens, thereby improving the assembly stability of the third lens, effectively reducing the assembly deformation of the third lens, and thus reducing field curvature and improving image quality. Attached Figure Description

[0023] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0024] Figure 1 A parameter annotation diagram of a visual system according to an optional embodiment of the present invention is shown;

[0025] Figure 2 and Figure 3 The diagrams show the structural schematics of the visual system of Embodiment 1-1 of this utility model in the first and second states, respectively.

[0026] Figure 4 and Figure 5 The diagrams show the structural schematics of the visual system in embodiments 1-2 of this utility model in the first and second states, respectively.

[0027] Figure 6 and Figure 7 The diagrams show the structural schematics of the visual systems of embodiments 1-3 of this utility model in the first and second states, respectively.

[0028] Figure 8 and Figure 9 The MTF curves of the visual system of Embodiment 1 of this utility model in the first state and the second state are shown respectively.

[0029] Figure 10 and Figure 11 The diagrams show the structural schematics of the visual system of Embodiment 2-1 of this utility model in the first and second states, respectively.

[0030] Figure 12 and Figure 13 The diagrams show the structural schematics of the visual system of Embodiment 2-2 of this utility model in the first and second states, respectively.

[0031] Figure 14 and Figure 15 The diagrams show the structural schematics of the visual system in embodiments 2-3 of this utility model in the first and second states, respectively.

[0032] Figure 16 and Figure 17 The MTF curves of the visual system of Embodiment 2 of this utility model in the first state and the second state are shown respectively;

[0033] Figure 18 and Figure 19 The diagrams show the structural schematics of the visual system of Embodiment 3-1 of this utility model in the first and second states, respectively.

[0034] Figure 20 and Figure 21 The diagrams show the structural schematics of the visual system of Embodiment 3-2 of this utility model in the first and second states, respectively.

[0035] Figure 22 and Figure 23 The diagrams show the structural schematics of the visual system of Embodiments 3-3 of this utility model in the first and second states, respectively.

[0036] Figure 24 and Figure 25 The MTF curves of the visual system of Embodiment 3 of this utility model in the first state and the second state are shown respectively.

[0037] The above figures include the following reference numerals:

[0038] E1, First lens; RP, Reflective polarizing element; QWP1, Quarter-wave plate; E2, Second lens; E3, Third lens; BS, Partial reflective element; Pa, First lens barrel; Pb, Second lens barrel; IMG, Image plane; IR / CG, Filter and / or protective glass. Detailed Implementation

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0041] In this utility model, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not used to limit this utility model.

[0042] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of this application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0043] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not drawn strictly to scale.

[0044] In this document, if a lens surface is convex and its location is not defined, it means that the lens surface is convex at least in the paraxial region; if a lens surface is concave and its location is not defined, it means that the lens surface is concave at least in the paraxial region. The paraxial region refers to the region near the optical axis. The surface of each lens closest to the first side (e.g., the human eye side) is called the first side surface of the lens, and the surface of each lens closest to the second side (e.g., the display screen side) is called the second side surface of the lens.

[0045] The visual system of the exemplary embodiments of this application can be simulated using software and / or tools such as ZEMAX and CODEV. Optionally, the visual system can be simulated using CODEV software. During the simulation process using software and / or tools as described above, the surface profile of each lens can be appropriately adjusted according to the built-in surface profile model of the software and / or tool used.

[0046] In order to solve the problem of poor field curvature performance of existing visual systems, this utility model provides a visual system.

[0047] like Figures 1 to 24As shown, the visual system includes a lens barrel assembly and an optical element assembly. The optical element assembly includes only three lenses with optical power. The lens barrel assembly includes a first lens barrel and a second lens barrel arranged sequentially from the first side to the second side along the optical axis. The optical element assembly includes a first optical element assembly and a second optical element assembly. The first optical element assembly rests within the first lens barrel, and the second optical element assembly rests within the second lens barrel. The first optical element assembly includes a first lens, a reflective polarizing element, a quarter-wave plate, and a second lens arranged sequentially from the first side to the second side along the optical axis. The second optical element assembly includes a third lens and a partially reflective element arranged sequentially from the first side to the second side along the optical axis. The first lens has positive optical power, and its first side surface is convex. The second lens... The third lens has optical power, and the second side of the third lens is convex. The second optical element group is configured to 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. The effective focal length f3 of the third lens, the inner diameter dbs of the first side end face of the second lens barrel, and the inner diameter dbm of the second side end face of the second lens barrel satisfy the following: 0.5 < f3 / (dbs+dbm) < 1.9. The maximum distance Lb between the first side end face of the second lens barrel and the second side end face of the second lens barrel on the optical axis, and the distance ΔL that the second optical element group moves along the optical axis when the visual system switches between the first state and the second state satisfy the following: 1.16 ≤ Lb / ΔL ≤ 3.10.

[0048] The visual system in this application consists of two lens barrels, three lenses, a reflective polarizing element, a quarter-wave plate, and some reflective elements. By rationally configuring the visual system to satisfy the condition 0.5 < f3 / (dbs+dbm) < 1.9, the inner diameter of the second lens barrel and the thickness of the third lens are limited. Simultaneously, the second lens barrel lacks other structures that support the third lens, easily leading to poor assembly stability of the third lens, resulting in poor field curvature and affecting image quality. To solve the field curvature problem caused by satisfying 0.5 < f3 / (dbs+dbm) < 1.9, this application controls Lb / ΔL within a reasonable range, ensuring a longer second lens barrel. This increases the bearing area between the second lens barrel and the outer ring surface of the third lens, thereby improving the assembly stability of the third lens, effectively reducing the assembly deformation of the third lens, and thus reducing field curvature and improving image quality.

[0049] Furthermore, to further illustrate the field curvature of the third lens when Lb / ΔL is in the range of 1.16 to 3.10 and when Lb / ΔL is outside the aforementioned range, refer to Table 1 below. Table 1 is a table of overall field curvature sensitivity for the third lens in a lens assembly, representing the overall field curvature sensitivity for different fields of view under an assembly distortion of 1 μm. In this table, S5 represents the first side surface of the third lens, S6 represents the second side surface of the third lens, 1 μm represents the assembly distortion, and 0F to 1.0F are normalized notations for the field of view. For example, 0F represents the center field of view of the visual system, 0.5F represents half of the maximum field of view of the visual system, and 1.0F represents the maximum field of view of the visual system. Typically, the overall field curvature sensitivity requirement for a visual system is ≤5 μm for a field curvature within 0.8F.

[0050] Referring to Table 1 below, Example 1 is a visual system that satisfies f3 / (dbs+dbm) within the range of 0.5 to 1.9 and Lb / ΔL greater than 3.1. The table shows that in Example 1, the first side of the third lens no longer meets the field curvature requirements at 0.6F and the second side at 0.4F. Furthermore, the overall field curvature sensitivity increases with increasing field of view. Example 2 is a visual system that satisfies f3 / (dbs+dbm) within the range of 0.5 to 1.9 and Lb / ΔL less than 1.16. The table shows that in Example 2, the first side of the third lens meets the field curvature requirements, while the second side no longer meets the requirements at 0.6F. Furthermore, the overall field curvature sensitivity generally increases with increasing field of view. One embodiment of this application is a visual system that satisfies f3 / (dbs+dbm) within the range of 0.5 to 1.9 and Lb / ΔL within the range of 1.16 to 3.10. As shown in Table 1, under various fields of view, the combined field curvature sensitivity of the first and second sides of the third lens is less than 1µm, meeting the field curvature requirements. Table 1 also shows that when the visual system satisfies 1.16≤Lb / ΔL≤3.10, the field curvature change is small and meets the field curvature requirements. However, when Lb / ΔL is less than 1.16 or greater than 3.10, the field curvature increases significantly, and in some fields of view, it exceeds the field curvature requirements. This indicates that when the visual system satisfies 1.16≤Lb / ΔL≤3.10, the first and second sides of the third lens still have good field curvature performance even with a deformation of 1µm.

[0051]

[0052]

[0053] Table 1

[0054] In some optional embodiments, the distance on the optical axis between the first optical element group and the display or image surface on the second side of the visual system can be fixed. The second optical element group can be configured 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, allowing the visual system to switch between a first state and a second state. Specifically, when the second optical element group moves to the position closest to the display or image surface, the distance on the optical axis between the second optical element group and the first optical element group is at its maximum, and the visual system can be in a +2D state, i.e., the first state. When the second optical element group moves to the position farthest from the display or image surface, the distance on the optical axis between the second optical element group and the first optical element group is at its minimum, and the visual system can be in a -5D state, i.e., the second state. The visual system of this application can achieve optical path reflection by reasonably setting the positions of lenses, reflective polarizing elements, quarter-wave plates, and some reflective elements, which can effectively shorten the length of the visual system, reduce the volume and weight of the visual system, and achieve the portability of the visual system.

[0055] For example, when the visual system is in the first state, its diopter is +2D, which is suitable for users with a diopter of +2D. When the visual system is in the second state, its diopter is -5D, which is suitable for users with a diopter of -5D. A negative sign for diopter indicates that the user is myopic; a positive sign indicates that the user is hyperopic. The specific value of diopter represents the user's refractive error. For example, +1D diopter indicates that the user's hyperopia is approximately 100 degrees, and -1D diopter indicates that the user's myopia is approximately 100 degrees.

[0056] It should be understood that, in addition to the first and second states, the visual system according to the embodiments of this application may also have other states, for example, between -5D and +2D. The visual system according to the embodiments of this application can achieve continuous zoom within the range of -5D to +2D, meeting the needs of users with different visual acuity, allowing users to enjoy VR experiences without wearing glasses.

[0057] In an exemplary embodiment, the visual system of this application may include at least one aperture stop. The aperture stop can constrain the optical path and control the light intensity. The aperture stop can be set at an appropriate position in the visual system as needed; for example, the aperture stop can be located between a first side (e.g., the human eye side) and a first lens.

[0058] In an exemplary embodiment, the virtual image distance VID of the visual system in the first state and the second state are different. The virtual image distance can be, for example, the distance on the optical axis from the virtual image formed by the image light from the second side at a predetermined position to the aperture. Wherein, VID = 1000 / diopter.

[0059] In some optional embodiments, 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, the center thickness CTQ of the quarter-wave plate on the optical axis, the center thickness CT2 of the second lens on the optical axis, and the maximum distance La between the first side end face and the second side end face of the first lens barrel satisfy the following condition: 0.95 < (CT1 + CTR + CTQ + CT2) / La < 1.45. By constraining (CT1 + CTR + CTQ + CT2) / La within a reasonable range, the length of the first optical element group can be constrained, which is beneficial for miniaturization of the visual system, reducing the overall weight, improving the user experience, and ensuring the structural strength of the first lens barrel. This, in turn, ensures the support effect of the first lens barrel on the first and second lenses, and guarantees the assembly stability of the first and second lenses. It can also indirectly constrain the thickness ratio of the first and second lenses, which is beneficial for the molding and bonding of the first and second lenses.

[0060] In some optional embodiments, the central thickness CT1 of the first lens on the optical axis and the inner diameter das of the first side end face of the first lens barrel satisfy the following condition: 7.20 ≤ das / CT1 ≤ 10.86. By constraining das / CT1 within a reasonable range, it is possible to ensure the light-transmitting aperture of the first side face of the first lens barrel, reduce light obstruction, and simultaneously ensure the central thickness of the first lens to guarantee its structural strength, thereby contributing to assembly stability and improving the manufacturability of the first lens.

[0061] In some optional embodiments, the difference Δf between the effective focal length of the visual system in the first state and the effective focal length of the visual system in the second state, the inner diameter dbs of the first side end face of the second lens barrel, and the inner diameter dam of the second side end face of the first lens barrel satisfy the following condition: 0.15 < Δf / (dbs-dam) < 2.7. By constraining Δf / (dbs-dam) within a reasonable range, it can be ensured that light can be smoothly transmitted between the first and second lens barrels in both the first and second states of the visual system, thereby ensuring clear imaging of the visual system during continuous zooming. If Δf / (dbs-dam) is less than 0.15, the difference between the inner diameter of the first side end face of the second lens tube and the inner diameter of the second side end face of the first lens tube will be large, which will cause some imaging light rays to be unable to enter the first lens tube and affect the imaging quality. If Δf / (dbs-dam) is greater than 2.7, the inner diameter dbs of the first side end face of the second lens tube will be close to the inner diameter dam of the second side end face of the first lens tube, which will cause light rays to hit the tube wall and form stray light.

[0062] In some alternative embodiments, the center thickness CT3 of the third lens, the outer diameter Dbs of the first side end face of the second lens barrel, and the outer diameter Dbm of the second side end face of the second lens barrel satisfy the following condition: 1.37 ≤ CT3 / (Dbs-Dbm) ≤ 4.29. By constraining CT3 / (Dbs-Dbm) within a reasonable range, the feasibility of forming the third lens and the second lens barrel is improved while ensuring the assembly stability of the visual system. At the same time, constraining the external dimensions of the second lens barrel helps to ensure that the visual system meets the miniaturization requirements.

[0063] In some optional embodiments, the effective focal length f1 of the first lens, the effective focal length f2 of the second lens, and the maximum distance La between the first side end face and the second side end face of the first lens barrel satisfy the following condition: 1.57mm ≤ |f1 / f2|×La ≤ 8.78mm. By constraining |f1 / f2|×La within a reasonable range, the length of the first lens barrel is effectively controlled, the overall height is reduced, which is beneficial for reducing the weight of the entire device and improving the user's head-wearing experience; on the other hand, it increases the focusing distance with the second optical element group, making the focusing range wider and the applicability stronger.

[0064] In some optional embodiments, the outer diameter Das of the first side end face of the first lens barrel, the outer diameter Dam of the second side end face of the first lens barrel, and the combined focal length fz of the first lens, the reflective polarizing element, the quarter-wave plate, and the second lens satisfy the following condition: 0.12 ≤ (Das + Dam) / fz ≤ 1.25. By reasonably controlling this condition range, the first optical element group can generate positive spherical aberration, which is balanced with the negative spherical aberration generated by other lenses in the system, thereby ensuring the imaging quality of the visual system. At the same time, controlling the outer diameter of the first lens barrel at the first and second end faces can constrain the size of the first lens barrel, which, while ensuring its structural strength, is conducive to the miniaturization of the visual system and improves the manufacturability of the lens barrel.

[0065] In some optional embodiments, the radius of curvature R1 of the first side surface of the first lens and the inner diameter das of the first side end face of the first lens barrel satisfy the following condition: 1.5 < R1 / das < 1.8. By constraining R1 / das within a reasonable range, on the one hand, the shape of the first lens is constrained, which helps to reduce the sensitivity of the first lens and thus improve the assembly yield; on the other hand, it can ensure that the inner diameter of the first lens barrel matches the refractive properties of the first lens, control the inner diameter size, and prevent the imaging light from being blocked and the stray light caused by non-imaging light from being blocked while ensuring the feasibility of forming the first lens barrel.

[0066] In some alternative embodiments, the radius of curvature R6 of the second side surface of the third lens and the outer diameter Dbm of the second side end face of the second lens barrel satisfy the following condition: -2.20 ≤ R6 / Dbm ≤ -1.39. By constraining R6 / Dbm within a reasonable range, the shape of the third lens is constrained, which helps to reduce the sensitivity of the third lens and thus improve the assembly yield; on the other hand, it can ensure the feasibility of forming the second lens barrel.

[0067] In some optional embodiments, the radius of curvature R5 of the first side surface of the third lens, the radius of curvature R4 of the second side surface of the second lens, and the maximum distance La between the first end face of the first lens barrel and the second end face of the first lens barrel satisfy the following: 1.67mm ≤ |R5 / R4|×La ≤ 14.59mm. Constraining |R5 / R4|×La within a reasonable range can constrain the shapes of the second and third lenses, which helps reduce their sensitivity and thus improves assembly yield. Simultaneously, constraining the maximum length of the first lens barrel within a reasonable range prevents it from excessively increasing the overall thickness and affecting user experience, while also preventing it from excessively decreasing and affecting the mechanical strength of the first lens barrel.

[0068] In some optional embodiments, the inner diameter das of the first side end face of the first lens barrel, the inner diameter dam of the second side end face of the first lens barrel, and the distance ΔL that the second optical element group moves along the optical axis when the visual system switches between the first and second states satisfy the following condition: 2.68 ≤ (dam-das) / ΔL ≤ 5.77. By reasonably controlling this conditional range, it is possible to prevent the visual system from extending too far beyond the lower limit, resulting in an excessively large maximum thickness of the entire device and affecting the user experience, and to prevent it from exceeding the upper limit, thus preventing the inability to accurately control the subdivision of the visual system from +2D to -5D. This facilitates system miniaturization while also ensuring the focus adjustment accuracy and stability of the system in different states within the +2D to -5D range. Simultaneously controlling the inner diameter of the first lens barrel helps improve the assembly stability of the first and second lenses.

[0069] In some optional embodiments, the difference Δf between the effective focal length of the visual system in the first state and the effective focal length of the visual system in the second state, the outer diameter Dbs of the first side end face of the second lens barrel, and the inner diameter dbm of the second side end face of the second lens barrel satisfy the following condition: 2.10 ≤ (Dbs - dbm) / Δf ≤ 11.45. By constraining (Dbs - dbm) / Δf within a reasonable range, it is possible to prevent it from exceeding the upper limit, which would increase the size of the visual system and affect the overall volume of the device, and to prevent it from falling below the lower limit, which would result in insufficient strength of the second lens barrel and affect the mechanical performance of the visual system.

[0070] In some optional embodiments, the effective focal length f3 of the third lens, the Abbe number V3 of the third lens, and the maximum distance Lb on the optical axis from the first end face to the second end face of the second lens barrel satisfy the following condition: 1.15 < Lb / (f3 / V3) < 2.5. By constraining Lb / (f3 / V3) within a reasonable range, the chromatic aberration of the third lens can be constrained, thereby reducing the chromatic aberration of the visual system and reducing the impact of the head-mounted device on the screen's chromaticity. At the same time, controlling the maximum length of the second lens barrel helps to shorten the overall size and reduce the overall weight, thereby increasing the user experience.

[0071] In some optional embodiments, the maximum distance La between the first side end face and the second side end face of the first lens barrel, and the outer diameter Dam of the second side end face of the first lens barrel, satisfy the following condition: 4.76 ≤ Dam / La ≤ 8.83. By constraining Dam / La within a reasonable range, the processing feasibility of the first lens barrel can be controlled, and the dispensing and assembly of the second lens is also facilitated. At the same time, the overall shape and length of the first lens barrel are constrained, which is beneficial to the miniaturization of the entire machine.

[0072] In some optional embodiments, the maximum distance Lb between the first and second side end faces of the second lens barrel on the optical axis and the outer diameter Dbs of the first side end face of the second lens barrel satisfy the following condition: 12.04 ≤ Dbs / Lb ≤ 14.25. Constraining Dbs / Lb within a reasonable range facilitates the processing feasibility of the first side end face of the second lens barrel, and also facilitates the dispensing and assembly of the third lens. Simultaneously, it constrains the overall shape and length dimensions of the second lens barrel, which is beneficial for the miniaturization of the entire device.

[0073] On the other hand, in another optional embodiment of this application, the visual system includes a lens barrel assembly and an optical element assembly. The optical element assembly includes only three lenses with optical power. The lens barrel assembly includes a first lens barrel and a second lens barrel arranged sequentially from the first side to the second side along the optical axis. The optical element assembly includes a first optical element assembly and a second optical element assembly, with the first optical element assembly resting inside the first lens barrel and the second optical element assembly resting inside the second lens barrel. The first optical element assembly includes a first lens, a reflective polarizing element, a quarter-wave plate, and a second lens arranged sequentially from the first side to the second side along the optical axis. The second optical element assembly includes a third lens and a partially reflective element arranged sequentially from the first side to the second side along the optical axis. The first lens has positive optical power, and the first side surface of the first lens is convex. The second lens has optical power, the third lens has positive optical power, and the second side of the third lens is convex. The second optical element group is configured to move along the optical axis to approach or move away from the display located on the second side, so that the visual system switches between the first state and the second state. The effective focal length f3 of the third lens, the inner diameter dbs of the first side end face of the second lens barrel, and the inner diameter dbm of the second side end face of the second lens barrel satisfy the following condition: 0.5 < f3 / (dbs+dbm) < 1.9. The inner diameter das of the first side end face of the first lens barrel, the inner diameter dam of the second side end face of the first lens barrel, and the distance ΔL that the second optical element group moves along the optical axis when the visual system switches between the first state and the second state satisfy the following condition: 2.68 ≤ (dam-das) / ΔL ≤ 5.77.

[0074] The visual system in this application consists of two lens barrels, three lenses, a reflective polarizing element, a quarter-wave plate, and some reflective elements. By reasonably setting up the visual system, under the premise of 0.5 < f3 / (dbs+dbm) < 1.9, the inner diameter of the second lens barrel and the thickness of the third lens are restricted. At the same time, there are no other structures in the second lens barrel that support the third lens, which easily leads to a decrease in the assembly stability of the third lens, resulting in a deterioration in the surface curvature and affecting the imaging quality. To address the field curvature issue caused by the condition 0.5 < f3 / (dbs+dbm) < 1.9, this application constrains (dam-das) / ΔL within a reasonable range, thus constraining the relationship between the size of the first lens barrel and the maximum distance the second optical element assembly can move along the optical axis. This allows for adjustable diopter within a smaller range of movement of the second optical element assembly, preventing excessive movement distance of the second optical element assembly from affecting the assembly stability of the third lens during movement. It also avoids excessive movement distance of the third lens leading to significant changes in the air gap between the second and third lenses, which would otherwise affect the field curvature sensitivity of the third lens, thus improving image quality. Simultaneously, constraining the inner diameter of the first lens barrel facilitates the miniaturization of the entire device and makes it easier to assemble the first and second lenses within the first lens barrel, preventing mismatch between the inner diameter of the first lens barrel and the first and second lenses from affecting assembly stability.

[0075] Of course, this embodiment may also include other parametric expressions from the optional embodiments described above, which will not be elaborated here.

[0076] Optionally, the aforementioned optical lens may also include protective glass for protecting the photosensitive element located on the imaging plane.

[0077] In this application, at least one of the first to the third dispersive lenses has an aspherical mirror surface. An aspherical lens is characterized by a continuously changing curvature from its center to its periphery. Unlike a spherical lens, which has a constant curvature from its center to its periphery, an aspherical lens has superior curvature radius characteristics, offering advantages in improving distortion and astigmatism. By using an aspherical lens, aberrations occurring during image formation can be eliminated as much as possible, thereby improving image quality.

[0078] However, those skilled in the art will understand that the number of lenses constituting the visual system can be varied to obtain the various results and advantages described herein without departing from the technical solutions claimed in this application. For example, although three lenses have been described as an example in the embodiments, the visual system is not limited to including three lenses. If necessary, the visual system may also include other numbers of lenses.

[0079] Figure 1 A schematic diagram showing the dimensions of a visual system according to an alternative embodiment of this application is illustrated. Figure 1 The parameters das, dam, Das, Dam, dbs, dbm, Dbs, Dbm, La, and Lb are clearly and intuitively illustrated to provide a clear understanding of their meaning. To facilitate the description of the visual system and the surface shape of specific lenses, these parameters will not be shown in the accompanying drawings when describing specific embodiments. In this application, the first side end face of the first lens barrel refers to the surface of the first lens barrel closest to the first side and perpendicular to the optical axis; the second side end face of the first lens barrel refers to the surface of the first lens barrel closest to the second side and perpendicular to the optical axis; the first side end face of the second lens barrel refers to the surface of the second lens barrel closest to the first side and perpendicular to the optical axis; and the second side end face of the second lens barrel refers to the surface of the second lens barrel closest to the second side and perpendicular to the optical axis. For example, the first side can be the human eye side, and the second side can be the display screen side.

[0080] The following description, with reference to the accompanying drawings, further illustrates examples of specific surface shapes and parameters applicable to the visual system described above.

[0081] It should be noted that in the following Embodiment 1, there are three examples: Embodiment 1-1, Embodiment 1-2, and Embodiment 1-3; in Embodiment 2, there are three examples: Embodiment 2-1, Embodiment 2-2, and Embodiment 2-3; and in Embodiment 3, there are three examples: Embodiment 3-1, Embodiment 3-2, and Embodiment 2-3. In the three examples within the same embodiment, the curvature radius, center thickness, and other parameters of the first to third lenses of the visual system, as well as the spacing between the lenses and the higher-order coefficients, are the same. However, the thickness, inner diameter, and outer diameter of the first and second lens barrels, and the shape of some lenses, are different. In other words, the main structure used for imaging is the same, but the auxiliary structures used for imaging are different.

[0082] It should be noted that any one of the examples in Embodiments 1 to 3 described below is applicable to this application.

[0083] Example 1

[0084] like Figures 2 to 9 As shown, the visual system of Embodiment 1 is described. Figure 2 A schematic diagram of the visual system of Embodiment 1-1 in its first state is shown. Figure 3 A schematic diagram of the visual system of Embodiment 1-1 in the second state is shown. Figure 4 A schematic diagram of the visual system of Embodiments 1-2 in the first state is shown. Figure 5 A schematic diagram of the visual system of Embodiments 1-2 in the second state is shown. Figure 6 The diagram shows the structural schematics of the visual systems of Embodiments 1-3 in the first state. Figure 7 A schematic diagram of the visual system of Embodiments 1-3 in the second state is shown.

[0085] like Figures 2 to 7 As shown, the visual system includes a first lens barrel Pa and a second lens barrel Pb arranged sequentially from the first side to the second side along the optical axis. The visual system also includes a first optical element group supported by the first lens barrel Pa and a second optical element group supported by the second lens barrel Pb. The first optical element group includes a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, and a second lens E2 arranged sequentially from the first side to the second side along the optical axis. The second optical element group includes a third lens E3 and a partially reflective element BS arranged sequentially from the first side to the second side along the optical axis. The reflective polarizing element RP is disposed on the second side of the first lens, the quarter-wave plate QWP is disposed on the second side of the reflective polarizing element RP, and the second lens is disposed on the second side of the quarter-wave plate QWP. This can be understood as the first lens E1, the reflective polarizing element RP, the quarter-wave plate QWP, and the second lens E2 being cemented together. The partially reflective element BS is disposed on the second side of the third lens.

[0086] In summary, the structural parameters of the visual system of Embodiment 1 under Embodiments 1-1, 1-2, and 1-3 are shown in Table 12.

[0087] In Embodiment 1, the first lens has positive optical power, a first side surface of the first lens is convex, and a second side surface of the first lens is planar; the second lens has positive optical power, a first side surface of the second lens is planar, and a second side surface of the second lens is convex; the third lens has positive optical power, a first side surface of the third lens is concave, and a second side surface of the third lens is convex. The visual system also includes an aperture stop located on the first side of the first lens.

[0088] Table 2 shows the basic structural parameters of the visual system in Embodiment 1, where the units for radius of curvature and thickness / distance are millimeters (mm). In Table 2, light from the image plane IMG propagates from plane number 20 to the side of plane number 1, and refraction / reflection refers to the refraction or reflection of light by that plane during this passage.

[0089] Face number Surface type radius of curvature thickness Refractive index Dispersion coefficient Refraction / Reflection Conic coefficient spherical endless D1 refraction 1 spherical endless 0.0000 refraction 2 Stabilizer (STO) spherical endless 12.0000 refraction 3 First lens (E1) aspherical 57.3525 4.8327 1.551 56.30 refraction -0.3176 4 Reflective polarizing element (RP) spherical endless 0.1180 1.487 57.47 refraction 5 Quarter-wave plate (QWP) spherical endless 0.1340 1.487 57.47 refraction 6 Second lens (E2) spherical endless 4.0461 1.551 56.30 refraction 7 aspherical -108.7162 D2 refraction 6.2155 8 Third lens (E3) aspherical -222.2712 3.3076 1.551 56.30 refraction 96.7299 9 Partial reflective element (BS) aspherical -64.1409 -3.3076 1.551 56.30 reflection -0.9418 10 aspherical -222.2712 D3 refraction 96.7299 11 aspherical -108.7162 -4.0461 1.551 56.30 refraction 6.2155 12 spherical endless -0.1340 1.487 57.47 refraction 13 Reflective polarizing element (RP) spherical endless 0.1340 1.487 57.47 reflection 14 Second lens (E2) spherical endless 4.0461 1.551 56.30 refraction 15 aspherical -108.7162 D4 refraction 6.2155 16 Third lens (E3) aspherical -222.2712 3.3076 1.551 56.30 refraction 96.7299 17 aspherical -64.1409 D5 refraction -0.9418 18 spherical endless 0.9000 1.519 64.17 refraction 19 spherical endless 0.0000 refraction 20 Image View (IMG) spherical endless 0.0000 refraction

[0090] Table 2

[0091] The parameters D1 to D5 in Table 2 can be understood as follows: D1 can be understood as the value of the virtual image distance of the visual system according to this embodiment. D2 can be understood as the value along the optical axis from the second side of the second lens to the first side of the third lens; D3 can be understood as the value along the optical axis from the first side of the third lens to the second side of the second lens; D4 can be understood as the value along the optical axis again from the second side of the second lens to the first side of the third lens; D5 can be understood as the value along the optical axis from the second side of the third lens to the first side of the filter and / or protective glass IR / CG located on the first side of the image plane IMG. It should be noted that during the transmission of light in the visual system, due to the presence of reflective polarizing elements, quarter-wave plates, and partial reflective elements, the light is reflected between some surfaces and will pass through the surface of some lenses multiple times. The distance of light transmission from the first side to the second side is positive, while the distance of light transmission from the second side to the first side is negative. During the zooming process of the second optical element group moving along the optical axis, the values ​​of the above parameters D1 to D5 will change accordingly.

[0092] The values ​​of D1 to D5 for the visual system in the first and second states are shown in Table 3 below.

[0093] D1 D2 D3 D4 D5 First state (+2D state) 500.0000 2.4964 -2.4964 2.4964 1.0000 Second state (-5D state) -200.0000 0.5000 -0.5000 0.5000 2.9964

[0094] Table 3

[0095] In Embodiment 1, the first side surface of the first lens, the second side surface of the second lens, the first side surface of the third lens, and the second side surface of the third lens are aspherical surfaces. The shape of each aspherical surface can be defined using, but is not limited to, the following aspherical formula:

[0096]

[0097] Where x is the distance vector from the vertex of the aspherical surface at a height h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R, that is, the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above; k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 4 below gives the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for the aspherical surface in Example 1.

[0098] Face number 3 7 16 17 A4 1.0169E-06 -3.9431E-06 -5.9739E-06 -2.1109E-07 A6 -4.2055E-09 5.7408E-09 2.4408E-09 -2.7191E-10 A8 8.4694E-12 -3.2742E-12 -3.9160E-13 1.0511E-12 A10 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A12 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A14 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A16 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A18 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A20 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0099] Table 4

[0100] Figure 8 and Figure 9 The MTF curves of the visual system of Embodiment 1 are shown in the first state and the second state, respectively. The MTF values ​​under the light of each field of view are all above 0.7, showing good imaging quality.

[0101] Example 2

[0102] like Figures 10 to 17 As shown, the visual system of Embodiment 2 is described. Figure 10 A schematic diagram of the visual system of Embodiment 2-1 in its first state is shown. Figure 11 A schematic diagram of the visual system of Embodiment 2-1 in the second state is shown. Figure 12 A schematic diagram of the visual system of Embodiment 2-2 in its first state is shown. Figure 13 A schematic diagram of the visual system of Embodiment 2-2 in the second state is shown. Figure 14 A schematic diagram of the visual system of Embodiments 2-3 in the first state is shown. Figure 15 A schematic diagram of the visual system of Embodiments 2-3 in the second state is shown.

[0103] like Figures 10 to 15As shown, the visual system includes a first lens barrel Pa and a second lens barrel Pb arranged sequentially from the first side to the second side along the optical axis. The visual system also includes a first optical element group supported by the first lens barrel Pa and a second optical element group supported by the second lens barrel Pb. The first optical element group includes a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, and a second lens E2 arranged sequentially from the first side to the second side along the optical axis. The second optical element group includes a third lens E3 and a partially reflective element BS arranged sequentially from the first side to the second side along the optical axis. The reflective polarizing element RP is disposed on the second side of the first lens, the quarter-wave plate QWP is disposed on the second side of the reflective polarizing element RP, and the second lens is disposed on the second side of the quarter-wave plate QWP. This can be understood as the first lens E1, the reflective polarizing element RP, the quarter-wave plate QWP, and the second lens E2 being cemented together. The partially reflective element BS is disposed on the second side of the third lens.

[0104] In summary, the structural parameters of the visual system of Embodiment 2 under Embodiments 2-1, 2-2, and 2-3 are shown in Table 12.

[0105] In Embodiment 2, the first lens has positive optical power, and both its first and second sides are convex. The second lens has negative optical power, and both its first and second sides are concave. The third lens has positive optical power, and both its first and second sides are convex. The visual system also includes an aperture stop located on the first side of the first lens.

[0106] Table 5 shows the basic structural parameters of the visual system in Embodiment 2, where the units for radius of curvature and thickness / distance are millimeters (mm). In Table 5, light from the image surface IMG propagates from surface 21 to surface 1, and refraction / reflection refers to the refraction or reflection of light by that surface during this passage.

[0107]

[0108]

[0109] Table 5

[0110] The values ​​of D1 to D5 for the visual system in the first and second states are shown in Table 6 below.

[0111] D1 D2 D3 D4 D5 First state (+2D state) 500.0000 1.8633 -1.8633 1.8633 0.1000 Second state (-5D state) -200.0000 0.7000 -0.7000 0.7000 0.3778

[0112] Table 6

[0113] Table 7 shows the higher-order coefficients that can be used for each aspherical mirror in this embodiment, wherein the surface shape of each aspherical surface can be defined by formula (1) given in Embodiment 1 above. In this embodiment, the first side surface of the first lens, the second side surface of the second lens, the first side surface of the third lens, and the second side surface of the third lens are aspherical surfaces.

[0114] Face number 3 7 16 17 A4 -6.2059E-07 -6.1402E-06 -8.6982E-06 -2.0727E-07 A6 1.0575E-08 -4.5660E-09 7.1854E-10 -1.7448E-09 A8 -7.7003E-12 5.1078E-12 -1.6743E-11 -3.0691E-13 A10 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A12 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A14 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A16 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A18 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A20 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0115] Table 7

[0116] Figure 16 and Figure 17 The MTF curves of the visual system of Embodiment 2 are shown in the first and second states, respectively. The MTF values ​​under the light of each field of view are all above 0.75, showing good imaging quality.

[0117] Example 3

[0118] like Figures 18 to 25 As shown, the visual system of Embodiment 3 is described. Figure 18 A schematic diagram of the visual system of Embodiment 3-1 in its first state is shown. Figure 19 A schematic diagram of the visual system of Embodiment 3-1 in the second state is shown. Figure 20 A schematic diagram of the visual system of Embodiment 3-2 in its first state is shown. Figure 21 A schematic diagram of the visual system of Embodiment 3-2 in the second state is shown. Figure 22 A schematic diagram of the visual system of Embodiment 3-3 in the first state is shown. Figure 23 A schematic diagram of the visual system of Embodiment 3-3 in the second state is shown.

[0119] like Figures 18 to 23 As shown, the visual system includes a first lens barrel Pa and a second lens barrel Pb arranged sequentially from the first side to the second side along the optical axis. The visual system also includes a first optical element group supported by the first lens barrel Pa and a second optical element group supported by the second lens barrel Pb. The first optical element group includes a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, and a second lens E2 arranged sequentially from the first side to the second side along the optical axis. The second optical element group includes a third lens E3 and a partially reflective element BS arranged sequentially from the first side to the second side along the optical axis. The reflective polarizing element RP is disposed on the second side of the first lens, the quarter-wave plate QWP is disposed on the second side of the reflective polarizing element RP, and the second lens is disposed on the second side of the quarter-wave plate QWP. This can be understood as the first lens E1, the reflective polarizing element RP, the quarter-wave plate QWP, and the second lens E2 being cemented together. The partially reflective element BS is disposed on the second side of the third lens.

[0120] In summary, the structural parameters of the visual system in Embodiment 3 under Embodiments 3-1, 3-2, and 3-3 are shown in Table 12.

[0121] In Embodiment 3, the first lens has positive optical power, a first side surface of the first lens is convex, and a second side surface of the first lens is concave; the second lens has positive optical power, a first side surface of the second lens is convex, and a second side surface of the second lens is convex; the third lens has positive optical power, a first side surface of the third lens is convex, and a second side surface of the third lens is convex. The visual system also includes an aperture stop located on the first side of the first lens.

[0122] Table 8 shows the basic structural parameters of the visual system of Embodiment 3, where the units for radius of curvature and thickness / distance are millimeters (mm). In Table 8, light from the image surface IMG propagates from surface 21 to the side of surface 1, and refraction / reflection refers to the refraction or reflection of light by that surface during this passage.

[0123] Face number Surface type radius of curvature thickness Refractive index Dispersion coefficient Refraction / Reflection Conic coefficient spherical endless D1 refraction 1 spherical endless 0.0000 refraction 2 Stabilizer (STO) spherical endless 12.0000 refraction 3 First lens (E1) aspherical 64.5487 3.5000 1.490 70.40 refraction 1.3701 4 Reflective polarizing element (RP) spherical 527.9075 0.1180 1.487 57.47 refraction 5 Quarter-wave plate (QWP) spherical 527.9075 0.1340 1.487 57.47 refraction 6 Second lens (E2) spherical 527.9075 3.7765 1.490 70.40 refraction 7 aspherical -500.0000 D2 refraction 4.3746 8 Third lens (E3) aspherical 151.7201 3.7477 1.490 70.40 refraction -5.6027 9 Partial reflective element (BS) aspherical -105.3251 -3.7477 1.490 70.40 reflection 1.5612 10 aspherical 151.7201 D3 refraction -5.6027 11 aspherical -500.0000 -3.7765 1.490 70.40 refraction 4.3746 12 spherical 527.9075 -0.1340 1.487 57.47 refraction 13 Reflective polarizing element (RP) spherical 527.9075 0.1340 1.487 57.47 reflection 14 Second lens (E2) spherical 527.9075 3.7765 1.490 70.40 refraction 15 aspherical -500.0000 D4 refraction 4.3746 16 Third lens (E3) aspherical 151.7201 3.7477 1.490 70.40 refraction -5.6027 17 aspherical -105.3251 D5 refraction 1.5612 18 spherical endless 0.2000 refraction 19 spherical endless 0.7000 1.519 64.17 refraction 20 spherical endless 0.0000 refraction 21 Image View (IMG) spherical endless 0.0000 refraction

[0124] Table 8

[0125] The values ​​of D1 to D5 for the visual system in the first and second states are shown in Table 9 below.

[0126] D1 D2 D3 D4 D5 First state (+2D state) 500.0000 5.8715 -5.8715 5.8715 0.1000 Second state (-5D state) -200.0000 2.6460 -2.6460 2.6460 2.4206

[0127] Table 9

[0128] Table 10 shows the higher-order coefficients that can be used for each aspherical mirror in this embodiment, wherein the surface shape of each aspherical surface can be defined by formula (1) given in Embodiment 1 above. In this embodiment, the first side surface of the first lens, the second side surface of the second lens, the first side surface of the third lens, and the second side surface of the third lens are aspherical surfaces.

[0129] Face number 3 7 16 17 A4 3.1529E-06 -4.7305E-06 -9.8957E-06 -7.1448E-07 A6 -3.5374E-09 -4.3884E-09 1.3914E-09 1.6825E-10 A8 6.1799E-12 7.7723E-12 -8.7757E-13 1.9656E-12 A10 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A12 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A14 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A16 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A18 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A20 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0130] Table 10

[0131] Figure 24 and Figure 25 The MTF curves of the visual system of Embodiment 3 are shown in the first and second states, respectively. The MTF values ​​under the light of each field of view are all above 0.7, showing good imaging quality.

[0132] In summary, embodiments one through three of the visual system satisfy the relationships shown in Table 11. Specifically, the conditional values ​​for the first and second states corresponding to each embodiment of the visual system are identical.

[0133] Conditional / Example 1-1 1-2 1-3 2-1 2-2 2-3 3-1 3-2 3-3 f3 / (dbs+dbm) 1.88 1.88 1.87 0.54 0.53 0.54 1.37 1.35 1.37 Lb / ΔL 1.72 1.82 1.97 2.89 3.10 2.96 1.22 1.31 1.16 (CT1+CTR+CTQ+CT2) / La 1.28 1.43 1.40 0.96 1.02 0.98 1.11 1.24 1.37 das / CT1 7.34 7.72 7.62 7.20 7.24 7.25 10.66 10.86 10.45 Δf / (dbs-dam) 0.52 0.45 0.71 0.16 0.16 0.20 2.67 1.18 2.04 CT3 / (Dbs-Dbm) 2.36 1.37 2.62 4.29 4.29 4.29 2.41 2.44 2.41 |f1 / f2|×La(mm) 3.77 3.38 3.43 8.78 8.21 8.58 1.93 1.74 1.57 (Das+Dam) / fz 1.24 1.25 1.25 0.12 0.12 0.12 0.83 0.81 0.81 R1 / das 1.62 1.54 1.56 1.55 1.54 1.54 1.73 1.70 1.77 R6 / Dbm -1.40 -1.45 -1.39 -1.54 -1.55 -1.56 -2.15 -2.13 -2.20 |R5 / R4|×La(mm) 14.59 13.09 13.31 7.25 6.78 7.08 2.06 1.85 1.67 (dam-das) / ΔL 3.63 2.68 3.11 5.66 5.77 5.66 3.25 2.86 3.14 (Dbs-dbm) / Δf 4.90 4.93 4.77 11.45 9.72 11.45 2.74 2.71 2.10 Lb / (f3 / V3) 1.19 1.26 1.36 2.32 2.49 2.38 2.18 2.34 2.07 Dam / La 6.31 6.95 7.00 4.76 5.19 4.92 7.39 8.04 8.83 Dbs / Lb 13.68 12.84 12.04 14.25 13.22 13.77 12.78 12.05 13.21

[0134] Table 11

[0135] Table 12 provides some parameters of the visual systems in Examples 1 to 3, in mm.

[0136]

[0137]

[0138] Table 12

[0139] This application also provides an imaging device, whose electronic photosensitive element can be a photocoupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The imaging device can be a stand-alone imaging device or an imaging module integrated into a mobile electronic device. The imaging device is equipped with the visual system described above.

[0140] Obviously, the embodiments described above are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0141] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0142] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0143] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A visual system, characterized in that, It includes a lens barrel assembly and an optical element assembly, wherein the optical element assembly consists of only three lenses with optical power. The lens barrel assembly includes a first lens barrel and a second lens barrel arranged sequentially from the first side to the second side along the optical axis; The optical element group includes a first optical element group and a second optical element group, wherein the first optical element group is supported inside the first lens barrel and the second optical element group is supported inside the second lens barrel; The first optical element group includes a first lens, a reflective polarizing element, a quarter-wave plate, and a second lens arranged sequentially along the optical axis from the first side to the second side. The second optical element group includes a third lens and a partially reflective element arranged sequentially along the optical axis from the first side to the second side. The first lens has positive optical power and its first side surface is convex. The second lens has optical power, and the third lens has positive optical power and its second side surface is convex. The second optical element group is configured to move along the optical axis to approach or move away from the display located on the second side, so that the visual system switches between a first state and a second state; The effective focal length f3 of the third lens, the inner diameter dbs of the first side end face of the second lens barrel, and the inner diameter dbm of the second side end face of the second lens barrel satisfy the following condition: 0.5 < f3 / (dbs+dbm) < 1.9; The maximum distance Lb between the first side end face of the second lens barrel and the second side end face of the second lens barrel on the optical axis, and the distance ΔL that the second optical element group moves along the optical axis when the visual system switches between the first state and the second state, satisfy the following condition: 1.16≤Lb / ΔL≤3.

10.

2. The visual system according to claim 1, characterized in that, 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, the center thickness CTQ of the quarter-wave plate on the optical axis, the center thickness CT2 of the second lens on the optical axis, and the maximum distance La between the first side end face and the second side end face of the first lens barrel satisfy the following condition: 0.95 < (CT1 + CTR + CTQ + CT2) / La < 1.

45.

3. The visual system according to claim 1, characterized in that, The central thickness CT1 of the first lens on the optical axis and the inner diameter das of the first side end face of the first lens barrel satisfy the following condition: 7.20≤das / CT1≤10.

86.

4. The visual system according to claim 1, characterized in that, The difference Δf between the effective focal length of the visual system in the first state and the effective focal length of the visual system in the second state, the inner diameter dbs of the first side end face of the second lens barrel, and the inner diameter dam of the second side end face of the first lens barrel satisfy the following condition: 0.15 < Δf / (dbs-dam) < 2.

7.

5. The visual system according to claim 1, characterized in that, The central thickness CT3 of the third lens, the outer diameter Dbs of the first side end face of the second lens barrel, and the outer diameter Dbm of the second side end face of the second lens barrel satisfy the following condition: 1.37≤CT3 / (Dbs-Dbm)≤4.

29.

6. The visual system according to claim 1, characterized in that, The effective focal length f1 of the first lens, the effective focal length f2 of the second lens, and the maximum distance La between the first side end face and the second side end face of the first lens barrel satisfy the following condition: 1.57mm≤|f1 / f2|×La≤8.78mm.

7. The visual system according to claim 1, characterized in that, The outer diameter Das of the first side end face of the first lens barrel, the outer diameter Dam of the second side end face of the first lens barrel, the combined focal length fz of the first lens, the reflective polarizing element, the quarter-wave plate and the second lens satisfy the following condition: 0.12≤(Das+Dam) / fz≤1.

25.

8. The visual system according to claim 1, characterized in that, The radius of curvature R1 of the first side surface of the first lens and the inner diameter das of the first side end face of the first lens barrel satisfy the following condition: 1.5 < R1 / das < 1.

8.

9. The visual system according to claim 1, characterized in that, The radius of curvature R6 of the second side surface of the third lens and the outer diameter Dbm of the second side end face of the second lens barrel satisfy the following condition: -2.20≤R6 / Dbm≤-1.

39.

10. The visual system according to any one of claims 1 to 9, characterized in that, The radius of curvature R5 of the first side surface of the third lens, the radius of curvature R4 of the second side surface of the second lens, and the maximum distance La between the first end face of the first lens barrel and the second end face of the first lens barrel satisfy the following condition: 1.67mm≤|R5 / R4|×La≤14.59mm.

11. The visual system according to any one of claims 1 to 9, characterized in that, The inner diameter das of the first side end face of the first lens barrel, the inner diameter dam of the second side end face of the first lens barrel, and the distance ΔL that the second optical element group moves along the optical axis when the visual system switches between the first state and the second state satisfy the following condition: 2.68≤(dam-das) / ΔL≤5.

77.

12. The visual system according to any one of claims 1 to 9, characterized in that, The difference Δf between the effective focal length of the visual system in the first state and the effective focal length of the visual system in the second state, the outer diameter Dbs of the first side end face of the second lens barrel, and the inner diameter dbm of the second side end face of the second lens barrel satisfy the following condition: 2.10≤(Dbs-dbm) / Δf≤11.

45.

13. The visual system according to any one of claims 1 to 9, characterized in that, The effective focal length f3 of the third lens, the Abbe number V3 of the third lens, and 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 satisfy the following condition: 1.15 < Lb / (f3 / V3) < 2.

5.

14. The visual system according to any one of claims 1 to 9, characterized in that, The maximum distance La between the first side end face and the second side end face of the first lens barrel and the outer diameter Dam of the second side end face of the first lens barrel satisfy the following condition: 4.76≤Dam / La≤8.

83.

15. The visual system according to any one of claims 1 to 9, characterized in that, The maximum distance Lb between the first side end face and the second side end face of the second lens tube on the optical axis and the outer diameter Dbs of the first side end face of the second lens tube satisfy the following condition: 12.04≤Dbs / Lb≤14.25.

Images