Visual system

Abstract

The invention provides a visual system. The visual system comprises a first lens cone, a second lens cone, a first optical element group and a second optical element group, and the second optical element group is configured to be capable of moving along the optical axis of the visual system so as to be close to or far away from the first optical element group, so that the visual system is switched between a first state and a second state; when the visual system is switched between the first state and the second state, the distance delta L of the second optical element group moving along the optical axis and the minimum inner diameter damin of the first lens barrel meet the condition that damin / delta L is larger than or equal to 12.31 and smaller than or equal to 14.15; and the minimum inner diameter dbmin of the second lens barrel and the central thickness CT2 of the second lens on the optical axis meet the condition that dbmin / CT2 is greater than or equal to 4.47 and less than or equal to 7.71. According to the invention, the problem that the second lens cone of the visual system in the prior art is easy to generate reflection stray light is solved.

Description

Technical Field

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

[0002] With the further popularization of AR / VR (Augmented Reality / Virtual Reality) devices, consumers have put forward higher requirements for the thinness, imaging quality, and wearing experience of AR / VR. Traditional AR / VR devices based on aspherical and Fresnel technologies are very thick and heavy, and can no longer meet the needs of consumers. With the proposal of the catadioptric optical scheme, the problem of thinness and lightness of VR devices has been greatly improved and has become the mainstream scheme today.

[0003] Among the people using AR / VR, everyone's eyesight conditions are different, and there are many myopic or hyperopic users. Moreover, the myopia or hyperopia degrees of different people's eyes are also different. If a catadioptric module with a fixed focal length is used, the image quality seen is uneven, and the obtained experience effects vary greatly. A visual system with adjustable diopter has emerged, so that users with different eyesights can see clearly without wearing glasses and improve the VR visual experience. However, in the existing visual system, it usually includes a first optical element group located in a first barrel and a second optical element group located in a second barrel. The diopter is adjusted by changing the position of the second optical element group relative to the first optical element group. When the minimum inner diameter of the first barrel is relatively large with respect to the maximum moving distance of the second optical element group, the first barrel has a poor effect of intercepting stray light, resulting in the stray light formed by the reflection of the inner wall surface of the second barrel being able to enter the human eye, affecting the imaging quality and clarity. Summary of the Invention

[0004] The main purpose of the present invention is to provide a visual system to solve the problem of easy generation of reflected stray light in the second barrel of the visual system in the prior art.

[0005] To achieve the above object, according to one aspect of the present invention, a visual system is provided, which includes a lens barrel group and an optical element group. The optical element group only includes two lenses with optical power. 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 direction of the visual system. The optical element group includes a first optical element group and a second optical element group. The first optical element group is abutted in the first lens barrel, and a part of the second optical element group is abutted in the second lens barrel. The first optical element group includes a first lens, a polarizer, a reflective polarizing element, and a quarter-wave plate arranged in sequence from the first side to the second side along the optical axis direction. The second optical element group includes a second lens, a partial reflection element, and a display arranged in sequence from the first side to the second side along the optical axis direction. Among them, the first lens has a positive optical power, the first side of the first lens is convex, the second side of the first lens is flat, the second lens has a positive optical power, the first side of the second lens is convex, the second side of the second lens is convex, and the display is located on the second side of the second lens barrel. The second optical element group is configured to be movable along the optical axis of the visual system to approach or move away from the first optical element group, so that the visual system can switch between a first state and a second state. When the visual system switches between the first state and the second state, the distance ΔL that the second optical element group moves along the optical axis and the minimum inner diameter damin of the first lens barrel satisfy: 12.31 ≤ damin / ΔL ≤ 14.15; the minimum inner diameter dbmin of the second lens barrel and the central thickness CT2 of the second lens on the optical axis satisfy: 4.47 ≤ dbmin / CT2 ≤ 7.71.

[0006] According to another aspect of the present invention, a visual system is provided, which includes a lens barrel group and an optical element group. The optical element group only includes two lenses with optical power. 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 direction of the visual system. The optical element group includes a first optical element group and a second optical element group. The first optical element group abuts against the inside of the first lens barrel, and a part of the second optical element group abuts against the inside of the second lens barrel. The first optical element group includes a first lens, a polarizer, a reflective polarizing element, and a quarter-wave plate arranged in sequence from the first side to the second side along the optical axis direction. The second optical element group includes a second lens, a partial reflection element, and a display arranged in sequence from the first side to the second side along the optical axis direction. Among them, the first lens has a positive optical power, the first side surface of the first lens is a convex surface, the second side surface of the first lens is a flat surface, the second lens has a positive optical power, the first side surface of the second lens is a convex surface, the second side surface of the second lens is a convex surface, and the display is located on the second side of the second lens barrel. The second optical element group is configured to be movable along the optical axis of the visual system to approach or move away from the first optical element group, so that the visual system switches between a first state and a second state. The distance Lb between the first side end surface and the second side end surface of the second lens barrel in the optical axis direction, the curvature radius R3 of the first side surface of the second lens, and the curvature radius R4 of the second side surface of the second lens satisfy: 8.69 mm ≤ Lb × |R3 / R4| ≤ 21.53 mm. The minimum inner diameter dbmin of the second lens barrel and the central thickness CT2 of the second lens on the optical axis satisfy: 4.47 ≤ dbmin / CT2 ≤ 7.71.

[0007] Further, the distance Lb between the first side end surface and the second side end surface of the second lens barrel in the optical axis direction and 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 satisfy: 2.72 ≤ Lb / Δf ≤ 5.60.

[0008] Further, the distance La between the first side end surface and the second side end surface of the first lens barrel in the optical axis direction and the curvature radius R1 of the first side surface of the first lens satisfy: 8.86 ≤ R1 / La ≤ 15.64.

[0009] Further, the effective focal length f2 of the second lens and the minimum inner diameter dbmin of the second lens barrel satisfy: 3.58 ≤ f2 / dbmin ≤ 3.94.

[0010] Further, the inner diameter dam of the second 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 central thickness CT1 of the first lens on the optical axis satisfy: 1.61 ≤ (dam - das) / CT1 ≤ 2.64.

[0011] Furthermore, the distance Lb between the first side end face and the second side end face of the second lens barrel in the optical axis direction, the curvature radius R3 of the first side face of the second lens, and the curvature radius R4 of the second side face of the second lens satisfy: 8.69 mm ≤ Lb × |R3 / R4| ≤ 21.53 mm.

[0012] Furthermore, the combined focal length fz of the combination of the first lens, the polarizing plate, the reflective polarizing element, and the quarter-wave plate, and the outer diameter Das of the first side end face of the first lens barrel satisfy: 2.96 ≤ fz / Das ≤ 3.42.

[0013] Furthermore, the outer diameter Dbs of the first side end face of the second lens barrel, the outer diameter Dbm of the second side end face of the second lens barrel, and 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 satisfy: 1.00 ≤ (Dbs - Dbm) / Δf ≤ 2.27.

[0014] Furthermore, the inner diameter dbs of the first side end face of the second 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: 17.60 ≤ dbs / ΔL ≤ 19.83.

[0015] Furthermore, the minimum inner diameter damin of the first lens barrel and the effective focal length f1 of the first lens satisfy: 3.99 ≤ f1 / damin ≤ 4.94.

[0016] Furthermore, the outer diameter Dam of the second side end face of the first lens barrel and the curvature radius R3 of the first side face of the second lens satisfy: 4.88 ≤ R3 / Dam ≤ 7.57.

[0017] Furthermore, the inner diameter dbm of the second side end face of the second lens barrel and the distance BFL between the second side face of the second lens and the display on the optical axis satisfy: 36.20 ≤ dbm / BFL ≤ 43.34.

[0018] Furthermore, the minimum inner diameter damin of the first lens barrel and the entrance pupil diameter EPD of the visual system satisfy: 7.25 ≤ damin / EPD ≤ 8.10.

[0019] Furthermore, the outer diameter Das of the first side end face of the first lens barrel and the distance La between the first side end face and the second side end face of the first lens barrel in the optical axis direction satisfy: 5.34 ≤ Das / La ≤ 8.36.

[0020] Applying the technical solution of the present invention, the visual system includes a lens barrel group and an optical element group. The optical element group only includes two lenses with optical power. 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 direction of the visual system. The optical element group includes a first optical element group and a second optical element group. The first optical element group is abutted in the first lens barrel, and a part of the second optical element group is abutted in the second lens barrel. The first optical element group includes a first lens, a polarizer, a reflective polarizing element, and a quarter-wave plate arranged in sequence from the first side to the second side along the optical axis direction. The second optical element group includes a second lens, a partial reflection element, and a display arranged in sequence from the first side to the second side along the optical axis direction. Among them, the first lens has a positive optical power, the first side of the first lens is a convex surface, the second side of the first lens is a flat surface, the second lens has a positive optical power, the first side of the second lens is a convex surface, and the second side of the second lens is a convex surface. The display is located on the second side of the second lens barrel. The second optical element group is configured to be movable along the optical axis of the visual system to approach or move away from the first optical element group, so that the visual system switches between a first state and a second state. When the visual system switches between the first state and the second state, the distance ΔL that the second optical element group moves along the optical axis and the minimum inner diameter damin of the first lens barrel satisfy: 12.31 ≤ damin / ΔL ≤ 14.15. The minimum inner diameter dbmin of the second lens barrel and the central thickness CT2 of the second lens on the optical axis satisfy: 4.47 ≤ dbmin / CT2 ≤ 7.71.

[0021] The visual system in this application is formed by two lens barrels, two lenses, a polarizer, a reflective polarizing element, a quarter-wave plate, and a partial reflection element. On the premise of satisfying 12.31 ≤ damin / ΔL ≤ 14.15, the minimum inner diameter of the first lens barrel is relatively large with respect to the moving distance when the second optical element group switches between two states, resulting in a relatively large minimum inner diameter of the first lens barrel. The interception effect of the first lens barrel on stray light is reduced, resulting in that part of the stray light reflected by the inner wall surface of the second lens barrel cannot be effectively intercepted by the first lens barrel and enters the human eye, affecting the imaging quality. In order to solve the problem of stray light caused under the condition of 12.31 ≤ damin / ΔL ≤ 14.15, this application controls dbmin / CT2 within a reasonable range, controls the relationship between the minimum inner diameter of the second lens barrel and the central thickness of the second lens to control the deflection degree of light on the second lens, and further controls the position where the light enters the first optical element group, so that the stray light reflected by the inner wall surface of the second lens barrel is deflected to the outside of the human eye, reducing the stray light received by the human eye, which is beneficial to improving the imaging clarity and enhancing the user experience. Brief Description of the Drawings

[0022] The accompanying drawings of the specification, which form a part of this application, are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0023] Figure 1 A parameter annotation diagram of the visual system of an alternative embodiment of the present invention is shown;

[0024] Figure 2 And Figure 3 Schematic structural diagrams of the visual system of Embodiment 1-1 of the present invention in the first state and the second state are shown respectively;

[0025] Figure 4 And Figure 5 Schematic structural diagrams of the visual system of Embodiment 1-2 of the present invention in the first state and the second state are shown respectively;

[0026] Figure 6 And Figure 7 Schematic structural diagrams of the visual system of Embodiment 1-3 of the present invention in the first state and the second state are shown respectively;

[0027] Figure 8 And Figure 9 Optical modulation function curves of the visual system of Embodiment 1 of the present invention in the first state and the second state are shown respectively;

[0028] Figure 10 And Figure 11 Schematic structural diagrams of the visual system of Embodiment 2-1 of the present invention in the first state and the second state are shown respectively;

[0029] Figure 12 And Figure 13 Schematic structural diagrams of the visual system of Embodiment 2-2 of the present invention in the first state and the second state are shown respectively;

[0030] Figure 14 And Figure 15 Schematic structural diagrams of the visual system of Embodiment 2-3 of the present invention in the first state and the second state are shown respectively;

[0031] Figure 16 And Figure 17 Optical modulation function curves of the visual system of Embodiment 2 of the present invention in the first state and the second state are shown respectively;

[0032] Figure 18 And Figure 19 Schematic structural diagrams of the visual system of Embodiment 3-1 of the present invention in the first state and the second state are shown respectively;

[0033] Figure 20 AndFigure 21 Schematic diagrams of the visual system according to Embodiment 3-2 of the present invention are respectively shown in the first state and the second state;

[0034] Figure 22 and Figure 23 Schematic diagrams of the visual system according to Embodiment 3-3 of the present invention are respectively shown in the first state and the second state;

[0035] Figure 24 and Figure 25 Optical modulation function curves of the visual system according to Embodiment 3 of the present invention are respectively shown in the first state and the second state;

[0036] Figure 26 The stray light optical path diagram of the visual system according to an alternative embodiment of the present invention is shown;

[0037] Figure 27 The stray light optical path diagram of the visual system in an example is shown;

[0038] Figure 28 Shows Figure 27 The stray light spot diagram of the visual system in;

[0039] Figure 29 The stray light optical path diagram of the visual system in another example is shown;

[0040] Figure 30 Shows Figure 29 The stray light spot diagram of the visual system in.

[0041] Among them, the above-mentioned drawings include the following reference numerals:

[0042] E1, the first lens; LP, the polarizer; RP, the reflective polarizing element; QWP, the quarter-wave plate; E2, the second lens; BS, the partial reflection element; Pa, the first barrel; Pb, the second barrel; IMG, the display. Detailed Description of the Invention

[0043] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0044] It should be pointed out that unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0045] In the present invention, unless otherwise specified, the directional terms such as "upper, lower, top, bottom" generally refer to the directions shown in the drawings, or to the vertical, perpendicular or gravitational directions of the components themselves; similarly, for ease of understanding and description, "inner, outer" refer to the inner and outer of the contours of the respective components themselves, but the above directional terms are not used to limit the present invention.

[0046] In this text, if the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The 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.

[0047] To solve the problem that the second lens barrel of the visual system in the prior art is prone to generating reflected stray light, the present invention provides a visual system.

[0048] As Figures 1 to 25 shown, the visual system includes a lens barrel group and an optical element group. The optical element group only includes two lenses with optical power. 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 direction of the visual system; the optical element group includes a first optical element group and a second optical element group. The first optical element group abuts against the inside of the first lens barrel, and a part of the second optical element group abuts against the inside of the second lens barrel; the first optical element group includes a first lens, a polarizer, a reflective polarizing element, and a quarter-wave plate arranged in sequence from the first side to the second side along the optical axis direction. The second optical element group includes a second lens, a partially reflective element, and a display arranged in sequence from the first side to the second side along the optical axis direction. Among them, the first lens has a positive optical power, the first side surface of the first lens is convex, the second side surface of the first lens is flat, the second lens has a positive optical power, the first side surface of the second lens is convex, the second side surface of the second lens is convex, and the display is located on the second side of the second lens barrel; the second optical element group is configured to be able to move along the optical axis of the visual system to approach or move away from the first optical element group so that the visual system switches between a first state and a second state; when the visual system switches between the first state and the second state, the distance ΔL that the second optical element group moves along the optical axis and the minimum inner diameter damin of the first lens barrel satisfy: 12.31 ≤ damin / ΔL ≤ 14.15; the minimum inner diameter dbmin of the second lens barrel and the central thickness CT2 of the second lens on the optical axis satisfy: 4.47 ≤ dbmin / CT2 ≤ 7.71.

[0049] The visual system in this application is formed by two lens barrels, two lenses, a polarizer, a reflective polarizing element, a quarter-wave plate, and a partially reflective element. When the visual system satisfies 12.31 ≤ damin / ΔL ≤ 14.15, the minimum inner diameter of the first lens barrel is relatively large compared to the moving distance of the second optical element group during the switching between two states, resulting in a larger minimum inner diameter of the first lens barrel. The interception effect of the first lens barrel on stray light is reduced, causing some stray light formed by the reflection of the inner wall surface of the second lens barrel to not be effectively intercepted by the first lens barrel and enter the human eye, affecting the imaging quality. To solve the problem of stray light caused under the condition of 12.31 ≤ damin / ΔL ≤ 14.15, this application controls dbmin / CT2 within a reasonable range, controls the relationship between the minimum inner diameter of the second lens barrel and the central thickness of the second lens to control the deflection degree of light on the second lens, and further controls the position where the light enters the first optical element group, so that the stray light formed by the reflection of the inner wall surface of the second lens barrel is deflected outside the human eye, reducing the stray light received by the human eye, which is beneficial to improving the imaging clarity and enhancing the user experience.

[0050] The following stray light spot diagram simulates the Geometrical Ray SPOTS formed by geometric rays on the imaging surface, and also shows the energy intensity distribution of the stray light. The X and Y axes represent the spatial position of the imaging surface (unit: millimeter mm), demonstrating the peak position of the energy distribution of the stray light corresponding to the imaging surface. The color depth represents the strength of the energy of the stray light, that is, under the premise that the luminous flux of the chief ray is 1 lm, the luminous flux FLUX (unit: lumen lm) of the stray light per square millimeter on the imaging surface.

[0051] Optionally, the first lens barrel, the second lens barrel, the first optical element group, and the second optical element group of the visual system are configured as described above. At the same time, when the visual system satisfies 12.31 ≤ damin / ΔL ≤ 14.15, by setting dbmin / CT2 to satisfy different numerical ranges respectively, the following three different visual systems can be formed.

[0052] Figure 26 The stray light optical path of the visual system according to an optional embodiment of the present invention is shown. Specifically, Figure 26 The shown visual system satisfies dbmin / CT2 = 6.2. Hereinafter, this embodiment is referred to as Solution 1. In Solution 1, dbmin / CT2 is within the range of 4.47 ≤ dbmin / CT2 ≤ 7.71. From Figure 26 it can be seen that the stray light formed by the second lens barrel falls outside the receiving range of the human eye, reducing the stray light entering the human eye and ensuring the imaging clarity.

[0053] Figure 27 and Figure 28The stray light optical path and the stray light spot diagram of an exemplary visual system are respectively shown. Specifically, in this example, the visual system satisfies dbmin / CT2 = 3.4. Hereinafter, this example is referred to as Example 1. In Example 1, dbmin / CT2 is less than the lower limit value defined by 4.47 ≤ dbmin / CT2 ≤ 7.71. From Figure 27 and Figure 28 it can be seen that the inner inclined wall surface of the second lens barrel reflects stray light into the receiving range of the human eye, and the intensity of the stray light is relatively high, which has a greater impact on the imaging effect.

[0054] Figure 29 and Figure 30 The stray light optical path and the stray light spot diagram of another exemplary visual system are respectively shown. Specifically, in this example, the visual system satisfies dbmin / CT2 = 8.5. Hereinafter, this example is referred to as Example 2. In Example 2, dbmin / CT2 is greater than the upper limit value defined by 4.47 ≤ dbmin / CT2 ≤ 7.71. From Figure 29 and Figure 30 it can be seen that the inner inclined wall surface of the second lens barrel reflects stray light into the receiving range of the human eye, and the intensity of the stray light is relatively high, which has a greater impact on the imaging effect.

[0055] In summary, when 4.47 ≤ dbmin / CT2 ≤ 7.71 is satisfied, there is no stray light in the receiving range of the human eye, and the imaging effect is good, which can solve the stray light problem caused by 12.31 ≤ damin / ΔL ≤ 14.15. It should be noted that in this application, damin / ΔL and dbmin / CT2 are restricted within a reasonable range, which can reduce stray light, and does not depend on the optical power and surface shape of other lenses. The optical power and surface shape of other lenses are further optimizations of the visual system on this basis. The optical power of each of the other lenses can be positive or negative according to the design requirements of the actual visual system, and the surface shape of each lens can also be convex or concave according to the design requirements of the visual system. When the visual system satisfies: 12.31 ≤ damin / ΔL ≤ 14.15; 4.47 ≤ dbmin / CT2 ≤ 7.71, it can ensure that the visual system has a low stray light risk.

[0056] For example, in some alternative embodiments, the first lens has a positive optical power, and the second lens has a positive optical power. Also, for example, in some alternative embodiments, the first side surface of the first lens is convex, and the second side surface of the first lens is flat. The first side surface of the second lens is convex, and the second side surface of the second lens is convex. By reasonably restricting the surface shape of each lens, it is beneficial to reasonably restrict the light path, ensure the smooth transition of light, and is beneficial to correcting aberrations.

[0057] In some alternative embodiments, the distance of the first optical element group from the display on the second side of the visual system along the optical axis can be adjusted, the distance of the second lens from the display along the optical axis can be fixed, and the second optical element group can be configured to be movable along the optical axis closer to or farther from the first optical element group, so that the visual system can be switched between a first state and a second state.

[0058] Specifically, when the second optical element group moves to the position farthest from the first optical element group, the visual system can be in the +2D state, that is, the first state; when the second optical element group moves to the position closest to the first optical element group, the visual system can be in the -5D state, that is, the second state.

[0059] Exemplarily, when the visual system is in the first state, the diopter of the visual system is +2D, and it can be applicable to users with a diopter of +2D, for example; when the visual system is in the second state, the diopter of the visual system is -5D, and it can be applicable to users with a diopter of -5D, for example. Among them, when the sign of the diopter is negative, it can indicate that the user is a myopic user; when the sign of the diopter is positive, it can indicate that the user is a hyperopic user; the specific value of the diopter can represent the refractive power of the user. For example, a diopter of +1D can indicate that the user's hyperopia degree is about 100 degrees, and a diopter of -1D can indicate that the user's myopia degree is about 100 degrees.

[0060] It should be understood that in addition to the first state and the second state, the visual system according to the embodiments of the present application can also have other states, for example, between -5D and +2D. The visual system according to the embodiments of the present application can achieve continuous zoom within the range of -5D to +2D, can meet the needs of users with different visual acuities, and enables users to enjoy the VR experience without wearing glasses.

[0061] In an exemplary embodiment, the visual system of the present application can include at least one aperture stop. The aperture stop can restrict the light path and control the light intensity. The aperture stop can be set at an appropriate position of the visual system as needed. For example, the aperture stop can be located between the first side (such as the human eye side) and the first lens.

[0062] In an exemplary embodiment, the virtual image distance (VID) of the visual system is different in the first state and the second state. The virtual image distance can be, for example, the distance from the virtual image formed by the image light from the display at a predetermined position to the aperture stop on the optical axis. Among them, VID = 1000 / diopter.

[0063] In some alternative embodiments, the distance Lb between the first side end face and the second side end face of the second barrel in the optical axis direction, and 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 satisfy: 2.72 ≤ Lb / Δf ≤ 5.60. By constraining Lb / Δf within a reasonable range, while ensuring the structural strength of the second barrel, it is beneficial for the visual system to meet the requirements of miniaturization. If Lb / Δf exceeds the upper limit value, it is easy to cause an increase in the shape of the visual system and affect the volume of the whole machine. If Lb / Δf is less than the lower limit value, it is easy to cause insufficient strength of the second barrel and affect the mechanical performance of the visual system.

[0064] In some alternative embodiments, the distance La between the first side end face and the second side end face of the first barrel in the optical axis direction, and the curvature radius R1 of the first side surface of the first lens satisfy: 8.86 ≤ R1 / La ≤ 15.64. By constraining R1 / La within a reasonable range, the shape of the first lens can be controlled, which is beneficial to reducing the sensitivity of the first lens, and thus beneficial to improving the assembly yield of the visual system.

[0065] In some alternative embodiments, the effective focal length f2 of the second lens and the minimum inner diameter dbmin of the second barrel satisfy: 3.58 ≤ f2 / dbmin ≤ 3.94. By constraining f2 / dbmin within a reasonable range, the minimum inner diameter of the second barrel and the degree of deflection of light on the second lens are restricted, which is beneficial to reducing the stray light deflected into the second barrel, reducing the risk of stray light, and at the same time constraining the shape of the second lens and improving the processability of the second lens.

[0066] In some alternative embodiments, the inner diameter dam of the second side end face of the first barrel, the inner diameter das of the first side end face of the first barrel, and the central thickness CT1 of the first lens on the optical axis satisfy: 1.61 ≤ (dam - das) / CT1 ≤ 2.64. By constraining (dam - das) / CT1 within a reasonable range, it is beneficial to ensure the stability of the assembly of the first barrel and the first lens, and at the same time facilitate constraining the shape of the first lens and improving the processability of the first lens.

[0067] In some alternative embodiments, the distance Lb between the first side end face and the second side end face of the second lens barrel in the optical axis direction, the curvature radius R3 of the first side face of the second lens, and the curvature radius R4 of the second side face of the second lens satisfy: 8.69 mm ≤ Lb × |R3 / R4| ≤ 21.53 mm. By constraining Lb × |R3 / R4| within a reasonable range, on the one hand, the shape of the second lens can be constrained, which is beneficial to reducing the sensitivity of the second lens and improving the assembly yield of the visual system. On the other hand, it can ensure the matching of the length of the second lens barrel and the light refraction performance of the second lens, prevent non-imaging light from deflecting into the receiving range of the human eye while avoiding blocking the imaging light, reduce the risk of stray light, and ensure the light brightness at the same time.

[0068] In some alternative embodiments, the combined focal length fz of the first lens, the polarizer, the reflective polarizing element, and the quarter-wave plate and the outer diameter Das of the first side end face of the first lens barrel satisfy: 2.96 ≤ fz / Das ≤ 3.42. Constraining fz / Das within a reasonable range can effectively correct aberrations, improve the imaging quality, and at the same time ensure the efficient propagation of the light beam along a predetermined path, reducing the reflection and scattering of light on the barrel wall of the first lens barrel or other non-target surfaces, thereby effectively managing stray light and enhancing the user experience.

[0069] In some alternative embodiments, the outer diameter Dbs of the first side end face of the second lens barrel, the outer diameter Dbm of the second side end face of the second lens barrel, and 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 satisfy: 1.00 ≤ (Dbs - Dbm) / Δf ≤ 2.27. Constraining (Dbs - Dbm) / Δf within a reasonable range, on the one hand, can control the external dimensions of the visual system and avoid the overall dimensions of the whole machine being too large due to the large external dimensions of the visual system, which is not conducive to the miniaturization of the whole machine. On the other hand, it can ensure the structural strength of the second lens barrel and avoid the instability of the visual system caused by the low structural strength of the second lens barrel. When (Dbs - Dbm) / Δf is greater than 2.27, it is easy to cause the external dimensions of the visual system to be large. When (Dbs - Dbm) / Δf is less than 1, it is easy to cause insufficient strength of the second lens barrel. When (Dbs - Dbm) / Δf is in the range of 1 to 2.27, it can ensure the dimensions of the visual system and the structural strength of the second lens barrel at the same time.

[0070] In some alternative embodiments, the inner diameter dbs of the first side end face of the second 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: 17.60 ≤ dbs / ΔL ≤ 19.83. Constraining dbs / ΔL within a reasonable range is beneficial for controlling the light passing amount in different focal length states, so that the visual system has excellent optical performance in different focal length states. Constraining the range of dbs / ΔL can, on the one hand, prevent the problem of stray light caused by the large inner diameter of the first side end face of the second barrel, and on the other hand, avoid the problem of too low eye brightness caused by the small inner diameter of the first side end face of the second barrel, ensuring the optical performance of the visual system.

[0071] In some alternative embodiments, the minimum inner diameter damin of the first barrel and the effective focal length f1 of the first lens satisfy: 3.99 ≤ f1 / damin ≤ 4.94. Constraining f1 / damin within a reasonable range can, on the one hand, control the light flux and the degree of light deflection by the first lens, reducing the entry of stray light into the human eye while ensuring the light brightness, and on the other hand, constrain the shape of the first lens to facilitate the processing of the first lens.

[0072] In some alternative embodiments, the outer diameter Dam of the second side end face of the first barrel and the curvature radius R3 of the first side face of the second lens satisfy: 4.88 ≤ R3 / Dam ≤ 7.57. Constraining R3 / Dam within a reasonable range can, on the one hand, constrain the shape of the second lens, which is beneficial for reducing the sensitivity of the second lens, and thus beneficial for improving the assembly yield of the visual system, and on the other hand, is beneficial for the first barrel to meet the requirements of forming and miniaturization.

[0073] In some alternative embodiments, the inner diameter dbm of the second side end face of the second barrel and the distance BFL between the second side face of the second lens and the display on the optical axis satisfy: 36.20 ≤ dbm / BFL ≤ 43.34. Constraining dbm / BFL within a reasonable range can effectively control the light amount of the display passing through the second lens. On the one hand, it can prevent the eye brightness from being too low, and on the other hand, it can reduce the risk of generating stray light.

[0074] In some alternative embodiments, the minimum inner diameter damin of the first barrel and the entrance pupil diameter EPD of the visual system satisfy: 7.25 ≤ damin / EPD ≤ 8.10. Constraining damin / EPD within a reasonable range can ensure the eye brightness while reducing the generation of stray light. If damin / EPD is greater than 8.10, it will lead to a larger minimum inner diameter of the first barrel, which is likely to increase the risk of stray light passing through. If damin / EPD is less than 7.25, it will lead to a smaller minimum inner diameter of the first barrel, which is likely to block the light, and thus lead to a lower eye brightness, affecting the user experience.

[0075] In some alternative embodiments, the outer diameter Das of the first end face on the first side of the first lens barrel and the distance La between the first end face on the first side of the first lens barrel and the second end face on the second side of the first lens barrel in the optical axis direction satisfy: 5.34 ≤ Das / La ≤ 8.36. Constraining Das / La within a reasonable range is beneficial to controlling the overall shape and size of the first lens barrel, preventing interference between the first lens barrel and the second lens barrel during the focusing process, and is also beneficial to improving the processability of the first lens barrel.

[0076] On the other hand, in some other alternative embodiments, the visual system includes a lens barrel group and an optical element group. The optical element group only includes two lenses with optical power. 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 direction of the visual system; the optical element group includes a first optical element group and a second optical element group. The first optical element group abuts within the first lens barrel, and a part of the second optical element group abuts within the second lens barrel; the first optical element group includes a first lens, a polarizer, a reflective polarizing element, and a quarter-wave plate arranged in sequence from the first side to the second side along the optical axis direction, and the second optical element group includes a second lens, a partial reflection element, and a display arranged in sequence from the first side to the second side along the optical axis direction. Among them, the first lens has a positive optical power, the first side of the first lens is a convex surface, the second side of the first lens is a flat surface, the second lens has a positive optical power, the first side of the second lens is a convex surface, the second side of the second lens is a convex surface, and the display is located on the second side of the second lens barrel; the second optical element group is configured to be movable along the optical axis of the visual system to approach or move away from the first optical element group so that the visual system switches between a first state and a second state; the distance Lb between the first end face on the first side of the second lens barrel and the second end face on the second side of the second lens barrel in the optical axis direction, the curvature radius R3 of the first side of the second lens, and the curvature radius R4 of the second side of the second lens satisfy: 8.69 mm ≤ Lb × |R3 / R4| ≤ 21.53 mm; the minimum inner diameter dbmin of the second lens barrel and the central thickness CT2 of the second lens on the optical axis satisfy: 4.47 ≤ dbmin / CT2 ≤ 7.71.

[0077] The visual system in this application is formed by two lens barrels, two lenses, a polarizer, a reflective polarizing element, a quarter-wave plate, and a partially reflective element. When the visual system satisfies 8.69mm ≤ Lb × |R3 / R4| ≤ 21.53mm and 4.47 ≤ dbmin / CT2 ≤ 7.71, it is beneficial to restrict the length and inner diameter size of the second lens barrel, and at the same time control the path of light transmission in the second lens, so as to match the size of the second lens barrel with the light refraction performance of the second lens, reduce the reflection of light by the inner diameter surface of the second lens barrel, reduce the generation of stray light, and at the same time control the path of light exiting from the second optical element group, so that the stray light formed by the reflection of the inner wall surface of the second lens barrel is deflected to the outside of the human eye, reduce the stray light received by the human eye, which is beneficial to improving the imaging clarity and enhancing the user experience.

[0078] Of course, other parametric forms in the above optional embodiments may also be included in this embodiment, which will not be elaborated here one by one.

[0079] In this application, the mirror surface of at least one of the first lens and the second lens is an aspherical mirror surface. The characteristics of an aspherical lens are that the curvature changes continuously from the center of the lens to the periphery of the lens. Different from a spherical lens with a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has better curvature radius characteristics and has the advantages of improving distortion aberration and astigmatism aberration. After using an aspherical lens, it is possible to eliminate the aberration that appears during imaging as much as possible, thereby improving the imaging quality.

[0080] However, those skilled in the art should understand that without departing from the technical solutions claimed in this application, the number of lenses constituting the visual system can be changed to obtain the various results and advantages described in this specification. For example, although two lenses are described as an example in the embodiment, the visual system is not limited to including two lenses. If necessary, the visual system may also include other numbers of lenses.

[0081] Figure 1 The schematic diagram of the dimension marking of the visual system of an optional embodiment of this application is shown, Figure 1 Parameters such as das, dam, Das, Dam, damin, dbs, dbm, Dbs, Dbm, dbmin, La, and Lb are marked in it to clearly and intuitively understand the meaning of the parameters. For the convenience of describing the visual system and the surface shape of the specific lens, these parameters will no longer be shown in the subsequent description of specific embodiments.

[0082] The first side end face of the first lens barrel in this application 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. 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.

[0083] The following further describes, with reference to the accompanying drawings, examples of the specific surface profiles and parameters of the visual system applicable to the above embodiments.

[0084] It should be noted that in the following Example 1, there are Examples 1-1, 1-2, and 1-3. In Example 2, there are Examples 2-1, 2-2, and 2-3. In Example 3, there are Examples 3-1, 3-2, and 3-3. The curvature radii, central thicknesses, and other parameters of the first lens and the second lens of the visual system, as well as the spacing distances and higher-order term coefficients between the lenses, are the same under the three examples in the same embodiment. However, the thicknesses, inner diameters, and outer diameters of the first lens barrel and the second lens barrel, as well as the shapes of some of the lenses, are different. Or rather, the main structures for imaging are the same, while the auxiliary structures for imaging are different.

[0085] It should be noted that any of the following Examples 1 to 3 is applicable to this application.

[0086] Example 1

[0087] As Figures 2 to 9 shown, the visual system of Example 1 is described. Figure 2 Fig. shows the schematic structural diagram of the visual system of Example 1-1 in the first state. Figure 3 Fig. shows the schematic structural diagram of the visual system of Example 1-1 in the second state. Figure 4 Fig. shows the schematic structural diagram of the visual system of Example 1-2 in the first state. Figure 5 Fig. shows the schematic structural diagram of the visual system of Example 1-2 in the second state. Figure 6 Fig. shows the schematic structural diagram of the visual system of Example 1-3 in the first state. Figure 7 Fig. shows the schematic structural diagram of the visual system of Example 1-3 in the second state.

[0088] As Figures 2 to 7As shown, the visual system includes a first lens barrel Pa and a second lens barrel Pb arranged in sequence along the optical axis from the first side to the second side. The visual system further includes a first optical element group and a second optical element group. The first optical element group is supported inside the first lens barrel Pa and includes a first lens E1, a polarizer LP, a reflective polarizing element RP, and a quarter-wave plate QWP arranged in sequence along the optical axis from the first side to the second side. The second optical element group includes a second lens E2, a partial reflection element BS, and a display IMG arranged in sequence along the optical axis from the first side to the second side. The second lens E2 and the partial reflection element BS are supported inside the second lens barrel Pb, and the display IMG is located on the second side of the second lens barrel Pb. The polarizer LP is disposed on the second side surface of the first lens, the reflective polarizing element RP is disposed on the second side surface of the polarizer LP, and the quarter-wave plate QWP is disposed on the second side surface of the reflective polarizing element RP. It can be understood that the first lens E1, the polarizer LP, the reflective polarizing element RP, and the quarter-wave plate QWP are adhesively disposed. The partial reflection element BS is disposed on the second side surface of the second lens E2.

[0089] In this embodiment, the light from the display IMG sequentially passes through the second lens E2 and the quarter-wave plate QWP and then reaches the reflective polarizing element RP. After being reflected by the reflective polarizing element RP, the light passes through the quarter-wave plate QWP and the second lens E2 again and then reaches the partial reflection element BS on the second side surface of the second lens, is reflected by the partial reflection element BS, and then passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, the polarizer LP, and the first lens E1 and exits.

[0090] In summary, the structural parameters of the visual system in Embodiment 1 under Embodiments 1-1, 1-2, and 1-3 are shown in Table 11.

[0091] In Embodiment 1, the first lens has a positive optical power, the first side surface of the first lens is convex, and the second side surface of the first lens is flat; the second lens has a positive optical power, the first side surface of the second lens is convex, and the second side surface of the second lens is convex. The visual system further includes a diaphragm (STO), and the diaphragm is located on the first side of the first lens.

[0092] Table 1 shows the basic structural parameter table of the visual system of Example 1, in which the units of the radius of curvature and thickness / distance are all in millimeters (mm). In Table 1, the light from the display IMG propagates from surface number 16 to surface number 0, and the refraction / reflection is the refraction or reflection effect of the surface on the light during this passage. The surfaces represented by surface numbers 16 to 0 are, in order, the display, the second side surface of the second lens, the first side surface of the second lens, the second side surface of the quarter-wave plate, the first side surface of the quarter-wave plate (the second side surface of the reflective polarizing element), the second side surface of the quarter-wave plate, the first side surface of the second lens, the second side surface of the second lens (the first side surface of the partially reflective element), the first side surface of the second lens, the second side surface of the quarter-wave plate, the first side surface of the quarter-wave plate (the second side surface of the reflective polarizing element), the first side surface of the reflective polarizing element (the second side surface of the polarizing plate), the first side surface of the polarizing plate, the second side surface of the first lens, the first side surface of the first lens, the aperture surface, and the virtual image surface.

[0093] Table 1

[0094]

[0095] The parameters D1 to D4 in Table 1 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, that is, the value from the virtual image plane to the aperture plane along the optical axis. D2 can be understood as the value from the second side of the quarter wave plate QWP to the first side of the second lens along the optical axis; D3 can be understood as the value from the first side of the second lens to the second side of the quarter wave plate QWP along the optical axis, and D4 can be understood as the value from the second side of the quarter wave plate QWP to the first side of the second lens along the optical axis. It should be noted that during the transmission of light in the visual system, due to the presence of the reflective polarizing element, the quarter wave plate, and the partial reflection element, the light will be reflected between some surfaces and will pass through the surface of some lenses many times. The distance the light is transmitted from the first side to the second side is positive, and the distance the light is transmitted from the second side to the first side is negative. In the process of the second optical element group moving along the optical axis to achieve zooming, the values ​​of the above parameters D1 to D4 will change accordingly.

[0096] The values ​​of D1 to D4 of the visual system in the first state and the second state are shown in Table 2 below.

[0097] Table 2

[0098]

[0099] In the first embodiment, the first side surface of the first lens (i.e., surface number 2), the first side surface of the second lens (i.e., surface number 8, surface number 14), and the second side surface of the second lens (i.e., surface number 9, surface number 15) are aspherical surfaces, and the surface shape of each aspherical surface can be defined by, but not limited to, the following aspherical surface formula:

[0100] Formula (1);

[0101] Where x is the sagitta, the distance from the vertex of the aspheric surface when the aspheric surface is at a position with a height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c = 1 / R, that is, the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above; k is the conic coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. Table 3 below gives the higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 for the aspheric surface in Example 1.

[0102] Table 3

[0103]

[0104] Figure 8 and Figure 9 show the curves of the optical modulation function (MTF, Modulation Transfer Function) of the visual system in Example 1 in the first state and the second state respectively. Among them, curve 1 is the MTF curve of the 0 field of view in the meridional direction; curve 2 is the MTF curve of the 0.5 field of view in the meridional direction; curve 3 is the MTF curve of the 1 field of view in the meridional direction. From Figure 8 and Figure 9 it can be seen that the MTF values (optical modulation function values) of the light rays in each field of view at 15 line pairs / mm are all above 0.85, showing good imaging quality.

[0105] Example 2

[0106] As Figures 10 to 17 shown, the visual system of Example 2 is described. Figure 10 shows the schematic structural diagram of the visual system in Example 2-1 in the first state, Figure 11 shows the schematic structural diagram of the visual system in Example 2-1 in the second state, Figure 12 shows the schematic structural diagram of the visual system in Example 2-2 in the first state, Figure 13 shows the schematic structural diagram of the visual system in Example 2-2 in the second state, Figure 14 shows the schematic structural diagram of the visual system in Example 2-3 in the first state, Figure 15 shows the schematic structural diagram of the visual system in Example 2-3 in the second state.

[0107] As Figures 10 to 15As shown in the figure, the visual system includes a first lens barrel Pa and a second lens barrel Pb arranged in sequence from the first side to the second side along the optical axis. The visual system further includes a first optical element group and a second optical element group. The first optical element group is supported inside the first lens barrel Pa and includes a first lens E1, a polarizer LP, 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. The second optical element group includes a second lens E2, a partial reflection element BS, and a display IMG arranged in sequence from the first side to the second side along the optical axis. The second lens E2 and the partial reflection element BS are supported inside the second lens barrel Pb, and the display IMG is located on the second side of the second lens barrel Pb. The polarizer LP is disposed on the second side surface of the first lens, the reflective polarizing element RP is disposed on the second side surface of the polarizer LP, and the quarter-wave plate QWP is disposed on the second side surface of the reflective polarizing element RP. It can be understood that the first lens E1, the polarizer LP, the reflective polarizing element RP, and the quarter-wave plate QWP are adhesively disposed. The partial reflection element BS is disposed on the second side surface of the second lens E2.

[0108] In summary, the structural parameters of the visual system in Embodiment 2 under Embodiment 2-1, Embodiment 2-2, and Embodiment 2-3 are shown in Table 11.

[0109] In Embodiment 2, the first lens has a positive optical power. The first side surface of the first lens is convex, and the second side surface of the first lens is flat. The second lens has a positive optical power. The first side surface of the second lens is convex, and the second side surface of the second lens is convex. The visual system further includes a stop (STO), and the stop is located on the first side of the first lens.

[0110] Table 4 shows the basic structural parameter table of the visual system in Embodiment 2. Among them, the unit of the radius of curvature and the thickness / distance is millimeter (mm). In Table 4, the light from the display IMG propagates from surface number 16 to surface number 0, and the refraction / reflection is the refraction or reflection effect of the surface on the light during this passage. The surfaces represented by surface number 16 to surface number 0 are the display, the second side surface of the second lens, the first side surface of the second lens, the second side surface of the quarter-wave plate, the first side surface of the quarter-wave plate (the second side surface of the reflective polarizing element), the second side surface of the quarter-wave plate, the first side surface of the second lens, the second side surface of the second lens (the first side surface of the partial reflection element), the first side surface of the second lens, the second side surface of the quarter-wave plate, the first side surface of the quarter-wave plate (the second side surface of the reflective polarizing element), the first side surface of the reflective polarizing element (the second side surface of the polarizer), the first side surface of the polarizer, the second side surface of the first lens, the first side surface of the first lens, the stop surface, and the virtual image surface.

[0111] Table 4

[0112]

[0113] The numerical values of D1 to D4 of the visual system in the first state and the second state are shown in Table 5 below.

[0114] Table 5

[0115]

[0116] Table 6 shows the high-order term coefficients available for each aspheric surface in this embodiment. Among them, the surface shape of each aspheric surface can be defined by the formula (1) given in Embodiment 1 above. In this embodiment, the first side surface of the first lens (i.e., surface number 2), the first side surfaces of the second lens (i.e., surface numbers 8 and 14), and the second side surfaces of the second lens (i.e., surface numbers 9 and 15) are aspheric surfaces.

[0117] Table 6

[0118]

[0119] Figure 16 and Figure 17 show the optical modulation function curves (MTF, Modulation Transfer Function) of the visual system of Embodiment 2 in the first state and the second state respectively. Among them, Curve 1 is the MTF curve of the 0 field of view in the meridian direction; Curve 2 is the MTF curve of the 0.5 field of view in the meridian direction; Curve 3 is the MTF curve of the 1 field of view in the meridian direction. From Figure 16 and Figure 17 it can be seen that the MTF values (optical modulation function values) of the light rays in each field of view at 15 line pairs / mm are all above 0.8, showing good imaging quality.

[0120] Embodiment 3

[0121] As Figures 18 to 25 shown, the visual system of Embodiment 3 is described. Figure 18 shows the structural schematic diagram of the visual system of Embodiment 3-1 in the first state, Figure 19 shows the structural schematic diagram of the visual system of Embodiment 3-1 in the second state, Figure 20 shows the structural schematic diagram of the visual system of Embodiment 3-2 in the first state, Figure 21 shows the structural schematic diagram of the visual system of Embodiment 3-2 in the second state, Figure 22 shows the structural schematic diagram of the visual system of Embodiment 3-3 in the first state, Figure 23 shows the structural schematic diagram of the visual system of Embodiment 3-3 in the second state.

[0122] As Figures 18 to 23As shown, the visual system includes a first lens barrel Pa and a second lens barrel Pb arranged in sequence from the first side to the second side along the optical axis. The visual system further includes a first optical element group and a second optical element group. The first optical element group is supported within the first lens barrel Pa and includes a first lens E1, a polarizer LP, 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. The second optical element group includes a second lens E2, a partial reflection element BS, and a display IMG arranged in sequence from the first side to the second side along the optical axis. The second lens E2 and the partial reflection element BS are supported within the second lens barrel Pb, and the display IMG is located on the second side of the second lens barrel Pb. The polarizer LP is disposed on the second side surface of the first lens, the reflective polarizing element RP is disposed on the second side surface of the polarizer LP, and the quarter-wave plate QWP is disposed on the second side surface of the reflective polarizing element RP. It can be understood that the first lens E1, the polarizer LP, the reflective polarizing element RP, and the quarter-wave plate QWP are adhesively disposed. The partial reflection element BS is disposed on the second side surface of the second lens E2.

[0123] In summary, the structural parameters of the visual system in Embodiment 3 under Embodiment 3-1, Embodiment 3-2, and Embodiment 3-3 are shown in Table 11.

[0124] In Embodiment 3, the first lens has a positive optical power, the first side surface of the first lens is convex, and the second side surface of the first lens is flat; the second lens has a positive optical power, the first side surface of the second lens is convex, and the second side surface of the second lens is convex. The visual system further includes a stop (STO), and the stop is located on the first side of the first lens.

[0125] Table 7 shows the basic structural parameter table of the visual system in Embodiment 3, where the units of the radius of curvature and the thickness / distance are both millimeters (mm). In Table 7, the light rays from the display IMG propagate from surface number 16 to surface number 0, and the refraction / reflection is the refraction or reflection effect of the light by this surface during this passage. The surfaces represented by surface numbers 16 to 0 are the display, the second side surface of the second lens, the first side surface of the second lens, the second side surface of the quarter-wave plate, the first side surface of the quarter-wave plate (the second side surface of the reflective polarizing element), the second side surface of the quarter-wave plate, the first side surface of the second lens, the second side surface of the second lens (the first side surface of the partial reflection element), the first side surface of the second lens, the second side surface of the quarter-wave plate, the first side surface of the quarter-wave plate (the second side surface of the reflective polarizing element), the first side surface of the reflective polarizing element (the second side surface of the polarizer), the first side surface of the polarizer, the second side surface of the first lens, the first side surface of the first lens, the stop surface, and the virtual image surface.

[0126] Table 7

[0127]

[0128] The numerical values of D1 to D4 of the visual system in the first state and the second state are shown in Table 8 below.

[0129] Table 8

[0130]

[0131] Table 9 shows the high-order term coefficients available for each aspheric surface in this embodiment. Among them, the surface profiles of the aspheric surfaces can be defined by the formula (1) given in Embodiment 1 above. In this embodiment, the first side surface of the first lens (i.e., surface number 2), the first side surfaces of the second lens (i.e., surface numbers 8 and 14), and the second side surfaces of the second lens (i.e., surface numbers 9 and 15) are aspheric surfaces.

[0132] Table 9

[0133]

[0134] Figure 24 and Figure 25 show the curves of the optical modulation function (MTF, Modulation Transfer Function) of the visual system of Embodiment 3 in the first state and the second state respectively. Among them, Curve 1 is the MTF curve of the 0-field of view in the meridional direction; Curve 2 is the MTF curve of the 0.5-field of view in the meridional direction; Curve 3 is the MTF curve of the 1-field of view in the meridional direction. From Figure 24 and Figure 25 it can be seen that the MTF values (optical modulation function values) of the light rays in each field of view at 15 line pairs / mm are all above 0.85, showing good imaging quality.

[0135] In summary, Embodiments 1 to 3 of the visual system respectively satisfy the relationships shown in Table 10. Among them, the conditional value of the first state and the second state corresponding to each embodiment of the visual system is the same.

[0136] Table 10

[0137]

[0138] Table 11 gives some parameters of the visual systems of Embodiments 1 to 3, with the unit of mm.

[0139] Table 11

[0140]

[0141] The present application also provides an imaging device, the electronic photosensitive element of which may be a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor device (CMOS). The imaging device may be an independent imaging device or an imaging module integrated on a mobile electronic device. The imaging device is equipped with the visual system described above.

[0142] Obviously, the above-described embodiments are only some of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0143] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0144] It should be noted that the terms "first", "second", etc. in the description, claims and drawings of the present 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 under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order different from those illustrated or described herein.

[0145] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A visual system, characterized in that: The optical device comprises a lens barrel group and an optical element group, wherein the optical element group comprises only two lenses with optical power. The lens barrel assembly comprises a first lens barrel and a second lens barrel which are arranged in sequence from a first side to a second side along the optical axis direction of the visual system; The optical element group includes a first optical element group and a second optical element group, the first optical element group is supported in the first lens barrel, and a part of the second optical element group is supported in the second lens barrel; The first optical element group comprises a first lens, a polarizing plate, a reflective polarizing element, and a quarter wave plate arranged in sequence from the first side to the second side along the optical axis direction, and the second optical element group comprises a second lens, a partial reflective element, and a display arranged in sequence from the first side to the second side along the optical axis direction, wherein the first lens has positive optical power, the first side surface of the first lens is a convex surface, the second side surface of the first lens is a plane, the second lens has positive optical power, the first side surface of the second lens is a convex surface, the second side surface of the second lens is a convex surface, and the display is located on the second side of the second lens barrel; The second optical element group is configured to be movable along the optical axis of the visual system to be close to or away from the first optical element group, so as to switch the visual system between a first state and a second state; When the visual system switches between the first state and the second state, a distance ΔL moved by the second optical element group along the optical axis and a minimum inner diameter damin of the first lens barrel satisfy the following conditions: 12.31≤damin / ΔL≤14.15; A minimum inner diameter dbmin of the second lens barrel and a center thickness CT2 of the second lens on the optical axis satisfy the following: 4.47≤dbmin / CT2≤7.

71.

2. The visual system according to claim 1, characterized in that: The distance Lb between the first side end face of the second lens barrel and the second side end face of the second lens barrel in the optical axis direction, and 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 satisfy: 2.72≤Lb / Δf≤5.

60.

3. The visual system according to claim 1, characterized in that: A distance La between a first side end surface of the first lens barrel and a second side end surface of the first lens barrel in the optical axis direction and a curvature radius R1 of a first side surface of the first lens satisfy the following relationship: 8.86≤R1 / La≤15.

64.

4. The visual system according to claim 1, characterized in that: The effective focal length f2 of the second lens and the minimum inner diameter dbmin of the second lens barrel satisfy the following relationship: 3.58≤f2 / dbmin≤3.

94.

5. The visual system according to claim 1, characterized in that: An inner diameter dam of the second side end surface of the first lens barrel, an inner diameter das of the first side end surface of the first lens barrel, and a center thickness CT1 of the first lens on the optical axis satisfy the following relationship: 1.61≤(dam-das) / CT1≤2.

64.

6. The visual system according to claim 1, characterized in that: A distance Lb between the first side end surface of the second lens barrel and the second side end surface of the second lens barrel in the optical axis direction, a curvature radius R3 of the first side surface of the second lens, and a curvature radius R4 of the second side surface of the second lens satisfy: 8.69mm≤Lb×|R3 / R4|≤21.53mm.

7. The visual system according to claim 1, characterized in that: The combined focal length fz of the first lens, the polarizing plate, the reflective polarizing element, and the quarter-wave plate, and the outer diameter Das of the first side end surface of the first lens barrel satisfy the following relationship: 2.96≤fz / Das≤3.

42.

8. 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 outer diameter Dbm of the second side end surface of the second lens barrel, and 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 satisfy: 1.00≤(Dbs-Dbm) / Δf≤2.

27.

9. The visual system according to claim 1, characterized in that: An inner diameter dbs of the first side end surface of the second lens barrel and a 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: 17.60≤dbs / ΔL≤19.

83.

10. The visual system according to any one of claims 1 to 9, characterized in that: The minimum inner diameter damin of the first lens barrel and the effective focal length f1 of the first lens satisfy the following: 3.99≤f1 / damin≤4.

94.

11. The visual system according to any one of claims 1 to 9, characterized in that: An outer diameter Dam of the second side end surface of the first lens barrel and a curvature radius R3 of the first side surface of the second lens satisfy the following relationship: 4.88≤R3 / Dam≤7.

57.

12. The visual system according to any one of claims 1 to 9, characterized in that: An inner diameter dbm of the second side end surface of the second lens barrel and a distance BFL between the second side surface of the second lens and the display on the optical axis satisfy the following: 36.20≤dbm / BFL≤43.

34.

13. The visual system according to any one of claims 1 to 9, characterized in that: The minimum inner diameter damin of the first lens barrel and the entrance pupil diameter EPD of the visual system satisfy the following: 7.25≤damin / EPD≤8.

10.

14. The visual system according to any one of claims 1 to 9, characterized in that: An outer diameter Das of the first side end surface of the first lens barrel and a distance La between the first side end surface of the first lens barrel and the second side end surface of the first lens barrel in the optical axis direction satisfy the following: 5.34≤Das / La≤8.36.

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