Visual system and VR device comprising the same

Abstract

The application discloses a visual system, comprising a lens barrel and a first element group, a second element group and a third element group arranged in sequence from a first side to a second side along an optical axis and assembled in the lens barrel, wherein the first element group comprises a first lens, a reflective polarizing element and a quarter-wave plate; the second element group comprises a second lens; the third element group comprises a third lens; the air interval of the second lens and the third lens on the optical axis is smaller than the air interval of other adjacent lenses on the optical axis; the visual system further comprises a second spacer element located on the second side of the second lens and partially in contact with the second side surface of the second lens. The effective focal length F2 of the second element group, the effective focal length F3 of the third element group, the outer diameter D2m of the second side surface of the second spacer element and the inner diameter d2s of the first side surface of the second spacer element satisfy -8<(F2+F3) / (D2m+d2s)<0.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical elements, and more particularly to a visual system and a VR device comprising the same. BACKGROUND

[0002] In recent years, the metaverse industry is constantly upgrading, and consumers have higher requirements for the thinness, imaging quality and use experience of VR devices. However, the current imaging system generally has a series of problems such as large volume, poor imaging quality, high assembly manufacturing cost, etc.

[0003] In view of these problems, the technical personnel in the field need to design a thinner, high-performance and easy-to-manufacture visual system to provide users with better overall visual perception and use experience, while achieving the purpose of reducing cost and improving production efficiency. According to the current product development trend, the three-piece folding visual optical system design scheme will be more widely used in the future, therefore, it is expected to provide a three-piece folding visual optical system by reasonably designing the related parameters and structure forms of each optical component such as lenses, spacer elements and lens barrels, etc. which constitute the system, which can further shorten the size between the display and the visual system, make the visual optical system thinner, and improve the use comfort of the VR device; can expand the field of view range of the visual optical system, and make the virtual scene more real and vivid; can realize clear image and high-quality color restoration effect, better reduce distortion phenomenon, reduce ghost image and stray light phenomenon; and the design of the system can be more compact and simple, which is beneficial to large-scale assembly manufacturing and cost reduction. SUMMARY

[0004] The present application provides a visual system, which can include a lens barrel and a first element group, a second element group and a third element group arranged in order from a first side to a second side along an optical axis and assembled in the lens barrel, wherein the first element group includes a first lens, a reflective polarizing element and a quarter-wave plate; the second element group includes a second lens; the third element group includes a third lens; the air gap of the second lens and the third lens on the optical axis is smaller than the air gap of other adjacent lenses on the optical axis; the visual system further includes a second spacer element located at the second side of the second lens and partially in contact with the second side surface of the second lens. The effective focal length F2 of the second element group, the effective focal length F3 of the third element group, the outer diameter D2m of the second side surface of the second spacer element and the inner diameter d2s of the first side surface of the second spacer element can satisfy: -8<(F2+F3) / (D2m+d2s)<0.

[0005] In one embodiment, 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 outer diameter D2s of the first side surface of the second spacer element can satisfy: 0<|R5-R4| / (D2m+D2s)<50.

[0006] In one embodiment, the radius of curvature R6 of the second side surface of the third lens, the inner diameter d0m of the second side end surface of the lens barrel, and the aperture value Fno of the visual system can satisfy: -10<R6 / d0mxFno<0.

[0007] In one embodiment, the center thickness CT3 of the third lens along the optical axis, the maximum height L of the lens barrel in the direction of the optical axis, and the distance EP02 from the first side end surface of the lens barrel to the first side surface of the second spacer element along the optical axis can satisfy: 0<CT3 / (L-EP02)<3.

[0008] In one embodiment, the visual system further comprises a first spacer element located on the second side of the first lens and partially in contact with the second side surface of the first lens; the effective focal length F1 of the first element group and the inner diameter d1s of the first side surface of the first spacer element can satisfy: 0<|F1 / d1s|<28.

[0009] In one embodiment, the refractive index N1 of the first lens, the refractive index N2 of the second lens, the refractive index Nr of the reflective polarizing element, the refractive index Np of the quarter-wave plate, the distance EP02 from the first side end surface of the lens barrel to the first side surface of the second spacer element along the optical axis, and the distance EP01 from the first side end surface of the lens barrel to the first side surface of the first spacer element along the optical axis can satisfy: 0<(N1+N2+Nr+Np) / (EP02-EP01)<8.

[0010] In one embodiment, the visual system further comprises a first spacer element located on the second side of the first lens and partially in contact with the second side surface of the first lens; the effective focal length F1 of the first element group, the thickness CP1 of the first spacer element in the direction parallel to the optical axis, the thickness CP2 of the second spacer element in the direction parallel to the optical axis, the center thickness CT3 of the third lens along the optical axis, and the effective focal length f of the visual system can satisfy: 15mm<|F1xCP1+F2xCP2+F3xCT3| / f<86mm.

[0011] In one embodiment, the visual system further comprises a first spacer element located on the second side of the first lens and partially in contact with the second side surface of the first lens; the Abbe number Vr of the reflective polarizing element, the central thickness dr of the reflective polarizing element on the optical axis, the Abbe number Vp of the quarter wave plate, the central thickness dp of the quarter wave plate on the optical axis, and the distance EP12 of the second side surface of the first spacer element to the first side surface of the second spacer element on the optical axis can satisfy: 0 < (Vr x dr + Vp x dp) / (EP12 - dr - dp) < 15.

[0012] In one embodiment, the visual system further comprises a first spacer element located on the second side of the first lens and partially in contact with the second side surface of the first lens; the outer diameter D0s of the first side end surface of the lens barrel, the inner diameter d1s of the first side surface of the first spacer element, the central thickness CT2 of the second lens on the optical axis, the interval distance T23 of the second lens and the third lens on the optical axis, and the central thickness CT3 of the third lens on the optical axis can satisfy: -3 < (D0s - d1s) / (CT2 + T23 - CT3) < 8.

[0013] In one embodiment, the visual system further comprises a first spacer element located on the second side of the first lens and partially in contact with the second side surface of the first lens; the radius of curvature R2 of the second side surface of the first lens, the radius of curvature R3 of the first side surface of the second lens, and the distance EP12 of the second side surface of the first spacer element to the first side surface of the second spacer element on the optical axis can satisfy: 0 mm < R2 / R3 x EP12 < 15 mm.

[0014] In one embodiment, the quarter wave plate is attached to the reflective polarizing element, and the reflective polarizing element is attached to the second side surface of the first lens.

[0015] In one embodiment, the outer diameter D0m of the second side end surface of the lens barrel and the inner diameter d2m of the second side surface of the second spacer element can satisfy: 0 < |F3| / (D0m - d2m) < 40.

[0016] In one embodiment, the visual system further comprises a first spacer element located on the second side of the first lens and partially in contact with the second side surface of the first lens; the inner diameter d1m of the second side surface of the first spacer element can satisfy: 0 < |F2 / (d2s + d1m)| < 8.

[0017] In another aspect, the present application also provides a VR device, comprising the visual system provided by at least one of the above embodiments, wherein the first side is the human eye side, and the second side is the display side.

[0018] The visual system disclosed in the present application comprises a first element group, a second element group and a third element group arranged in sequence from a first side to a second side along an optical axis in a lens barrel, wherein the first element group comprises a first lens, a reflective polarizing element and a quarter-wave plate; the second element group comprises a second lens; the third element group comprises a third lens; the air gap of the second lens and the third lens on the optical axis is smaller than the air gap of other adjacent lenses on the optical axis; and a second spacer element is arranged on the second side of the second lens and in contact with the second side surface of the second lens; meanwhile, the effective focal length F2 of the second element group, the effective focal length F3 of the third element group, the outer diameter D2m of the second side surface of the second spacer element and the inner diameter d2s of the first side surface of the second spacer element satisfy the condition formula -8<(F2+F3) / (D2m+d2s)<0. The arrangement of the visual system disclosed in the present application can reasonably control the shape of the second lens and the third lens, ensure the light converging on the display, and help to ensure that the optical back focal length is not too long, so as to ensure the compactness of the visual system; can also reduce the air gap between lenses, help to reduce the occurrence of aberration phenomena such as field curvature and chromatic aberration, help to ensure the system clarity and color restoration requirements; meanwhile, it can ensure that the assembly has enough bearing area, and ensure the stability during assembly. BRIEF DESCRIPTION OF DRAWINGS

[0019] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments combined with the attached drawings. In the drawings:

[0020] Figure 1 The structure and part of the visual system according to the exemplary embodiments of the present application are shown in the schematic diagram;

[0021] Figure 2 , Figure 3 and Figure 4 The structure schematic diagrams of the visual system according to the embodiment 1 of the present application in three embodiments are shown in FIGS. 1-3, respectively;

[0022] Figure 5 , Figure 6 and Figure 7 The on-axis chromatic aberration curve, astigmatism curve and distortion curve of the visual system of the embodiment 1 are shown in FIGS. 4-6, respectively;

[0023] Figure 8 , Figure 9 and Figure 10 The structure schematic diagrams of the visual system according to the embodiment 2 of the present application in three embodiments are shown in FIGS. 7-9, respectively;

[0024] Figure 11 , Figure 12 and Figure 13 The on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the visual system of Example 2 are shown respectively.

[0025] Figure 14 , Figure 15 and Figure 16 Schematic diagrams of the visual system according to Embodiment 3 of this application are shown in three different implementations.

[0026] Figure 17 , Figure 18 and Figure 19 The on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the visual system of Example 3 are shown respectively.

[0027] Figure 20 The diagram illustrates the propagation path of light through a visual system according to an exemplary embodiment of this application; and

[0028] Figure 21 for Figure 20 The image shown is a partially enlarged view of the propagation path of light through the visual system of an exemplary embodiment of this application. Detailed Implementation

[0029] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0030] 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.

[0031] 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 strictly to scale.

[0032] In this context, the paraxial region refers to a region near the optical axis. If a lens surface is convex and the position of the convex surface is not specified, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the position of the concave surface is not specified, it means that the lens surface is concave at least in the paraxial region.

[0033] It should also be understood that the use of the terms "including", "comprising", "having" and / or "containing" when used in this specification, specifies the presence of stated features, elements and / or components, but do not preclude the presence or addition of one or more other features, elements, components and / or groups thereof. Furthermore, as used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. In addition, expressions such as "at least one of...", when preceding a list of two or more items, denote that at least one of each item in the list is present, but does not exclude the presence of all of the items or the addition of one or more items. Furthermore, as used herein, the use of the term "about" in relation to a measurement or a value means that the value is within a reasonable range of error for the measurement or value being made or used. In addition, as used herein, the term "substantially" means that a value is within 10% of a stated value. Furthermore, as used herein, the term "exemplary" is intended to mean an example or an illustration.

[0034] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0035] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other under the condition of no conflict. The following embodiments only express several implementation manners of the present application, which are described in a more specific and detailed manner, but should not be understood as a limitation on the patent scope of the present application. It should be pointed out that, for those skilled in the art, some modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0036] The features, principles, and other aspects of the present application are described in detail below.

[0037] The visual system according to the exemplary embodiments of the present application can include a lens barrel and a first element group, a second element group, and a third element group arranged in order from a first side to a second side along an optical axis, which are assembled in the lens barrel.

[0038] In the exemplary embodiments, the first element group can include at least a first lens, a reflective polarizing element, and a quarter wave plate. The second element group can include at least a second lens. The third element group can include at least a third lens.

[0039] In an example embodiment, the air separation of the second lens and the third lens on the optical axis can be smaller than the air separation of other adjacent lenses on the optical axis. Specifically, the air separation of the second lens and the third lens on the optical axis can be smaller than the air separation of the first lens and the second lens on the optical axis.

[0040] In an example embodiment, the visual system can further include a second spacer element located at the second side of the second lens, the second spacer element can be in partial contact with the second side surface of the second lens.

[0041] In an example embodiment, the visual system can further include a first spacer element located at the second side of the first lens, the first spacer element can be in partial contact with the second side surface of the first lens. It is to be understood that the surface of each element close to the first side and away from the second side is the first side surface of the element, and the surface of each element close to the second side and away from the first side is the second side surface of the element.

[0042] In an example embodiment, the first side can be, for example, the human eye side, and the second side can be, for example, the display side. The visual system can be used in various VR display devices, for example.

[0043] In an example embodiment, the visual system of the present application can satisfy the condition -8<(F2+F3) / (D2m+d2s)<0, where F2 is the effective focal length of the second element group, F3 is the effective focal length of the third element group, D2m is the outer diameter of the second side surface of the second spacer element, and d2s is the inner diameter of the first side surface of the second spacer element. By controlling the effective focal length of the second element group, the effective focal length of the third element group, the outer diameter of the second side surface of the second spacer element, and the inner diameter of the first side surface of the second spacer element to satisfy the condition -8<(F2+F3) / (D2m+d2s)<0, the shape of the second lens and the third lens can be reasonably controlled, the light can be ensured to converge on the display, the optical back focal length can be ensured not to be too long, which is conducive to ensuring the compactness of the visual system; at the same time, the air separation between lenses can be reduced, which is conducive to reducing the occurrence of aberration phenomena such as field curvature and chromatic aberration, ensuring the clarity and color restoration requirements of the system; it can also ensure that the assembly has enough bearing area to ensure stability during assembly.

[0044] In the exemplary embodiments, the visual system of the present application can satisfy the condition formula 0<|R5-R4| / (D2m+D2s)<50, wherein R5 is the radius of curvature of the first side of the third lens, R4 is the radius of curvature of the second side of the second lens, D2m is the outer diameter of the second side of the second spacer element, and D2s is the outer diameter of the first side of the second spacer element. By controlling the radius of curvature of the first side of the third lens, the radius of curvature of the second side of the second lens, the outer diameter of the second side of the second spacer element, and the outer diameter of the first side of the second spacer element to satisfy the condition formula 0<|R5-R4| / (D2m+D2s)<50, the radial positioning requirement of the lens can be ensured to be reasonably matched with the lens barrel, and a certain flange platform can be ensured at the edge of the lens to give a certain pin position requirement when the mold is designed. At the same time, the light rays on both sides can be emitted and incident at a small deflection angle, which can significantly reduce the aberration of the optical system and ensure the imaging quality. In addition, the complementary concave-convex surfaces can be realized in the structure, and the overall structure can be thinned and lightened.

[0045] In the exemplary embodiments, the visual system of the present application can satisfy the condition formula -10<R6 / d0mxFno<0, wherein R6 is the radius of curvature of the second side of the third lens, d0m is the inner diameter of the second side end surface of the lens barrel (i.e., the end surface or surface of the lens barrel closest to the second side), and Fno is the aperture value of the visual system. By controlling the radius of curvature of the second side of the third lens, the inner diameter of the second side end surface of the lens barrel, and the aperture value of the visual system to satisfy the condition formula -10<R6 / d0mxFno<0, the focal length of the entire system can be indirectly controlled under the premise of a certain size of the eye entrance pupil, and the position of the display can be reasonably determined. The edge field angle of the internal light rays of the system can be ensured to reach the maximum design requirement, and the system can satisfy the feature of the maximum FOV. At the same time, the deflection of the light rays can be controlled within a certain reasonable range.

[0046] In the exemplary embodiments, the visual system of the present application can satisfy the condition 0 < CT3 / (L-EP02) < 3, wherein CT3 is the center thickness of the third lens along the optical axis, L is the maximum height of the lens barrel along the optical axis, i.e. the distance between the first side end surface of the lens barrel (i.e. the end surface or surface of the lens barrel closest to the first side) and the second side end surface of the lens barrel along the optical axis, and EP02 is the distance between the first side end surface of the lens barrel and the first side surface of the second spacer element along the optical axis. By controlling the ratio of the center thickness of the third lens along the optical axis to the difference between the maximum height of the lens barrel along the optical axis and the distance between the first side end surface of the lens barrel and the first side surface of the second spacer element along the optical axis within the range, the entire system can be ensured not to be too long, the ratio of the height of the entire system to the outer diameter is more reasonable, the ratio of the center thickness of the third lens to the edge thickness can be ensured within a reasonable range, the injection molding process is stable, which is conducive to quality control, the front end (first side) of the lens barrel can be ensured to have a reasonable thickness and certain strength to ensure stability and no deformation during assembly, and the assembly of the first lens is also facilitated.

[0047] In the exemplary embodiments, the visual system of the present application can further include a first spacer element located at the second side of the first lens and partially in contact with the second side surface of the first lens, and the visual system can satisfy the condition 0 < |F1 / d1s| < 28, wherein F1 is the effective focal length of the first element group, and d1s is the inner diameter of the first side surface of the first spacer element. By controlling the absolute value of the ratio of the effective focal length of the first element group to the inner diameter of the first side surface of the first spacer element within the range, it can be ensured that the internal light is not blocked, and at the same time, the axial flange surface of the first lens can be positioned with a certain area; at the same time, it can be determined that the light emitted by the human eye can be deflected and all the light can enter the inner aperture of the first spacer element for light propagation to the next element until the display.

[0048] In the exemplary embodiments, the visual system of the present application can satisfy the condition formula 0 < (N1+N2+Nr+Np) / (EP02-EP01) < 8, wherein N1 is the refractive index of the first lens, N2 is the refractive index of the second lens, Nr is the refractive index of the reflective polarizing element, Np is the refractive index of the quarter-wave plate, EP02 is the distance from the first side end surface of the lens barrel to the first side surface of the second spacer element on the optical axis, and EP01 is the distance from the first side end surface of the lens barrel to the first side surface of the first spacer element on the optical axis. By controlling the refractive index of the first lens, the refractive index of the second lens, the refractive index of the reflective polarizing element, the refractive index of the quarter-wave plate, the distance from the first side end surface of the lens barrel to the first side surface of the second spacer element on the optical axis, and the distance from the first side end surface of the lens barrel to the first side surface of the first spacer element on the optical axis to satisfy the condition formula 0 < (N1+N2+Nr+Np) / (EP02-EP01) < 8, the optical power between the first and second lenses can be reasonably distributed, which is conducive to clear and high-quality system imaging and can balance the optical higher-order aberration; wherein the refractive index of the polarizing element and the wave plate is selected to be close to or similar to the refractive index of the lens, so as to prevent the refractive index of the interface from being too different, thereby avoiding the occurrence of light energy loss; at the same time, the thickness of the flange bearing surface of the intermediate second lens can be indirectly controlled, so as to ensure that the thickness of the flange surface of the second lens and the center thickness of the lens are not too different, which is conducive to the stability of the forming process and the forming quality.

[0049] In the exemplary embodiments, the visual system of the present application can further include a first spacer element located on the second side of the first lens and partially in contact with the second side surface of the first lens, and the visual system can satisfy the condition formula 15mm < |F1×CP1+F2×CP2+F3×CT3| / f < 86mm, wherein F1 is the effective focal length of the first element group, CP1 is the thickness of the first spacer element along the direction parallel to the optical axis, F2 is the effective focal length of the second element group, CP2 is the thickness of the second spacer element along the direction parallel to the optical axis, F3 is the effective focal length of the third element group, CT3 is the center thickness of the third lens on the optical axis, and f is the effective focal length of the visual system. By controlling the effective focal length of the first element group, the thickness of the first spacer element along the direction parallel to the optical axis, the effective focal length of the second element group, the thickness of the second spacer element along the direction parallel to the optical axis, the effective focal length of the third element group, the center thickness of the third lens on the optical axis, and the effective focal length of the visual system to satisfy the condition formula 15mm < |F1×CP1+F2×CP2+F3×CT3| / f < 86mm, the optical power of the system can be effectively distributed, the optical system aberration can be corrected or balanced under the premise of satisfying the system focal length, and the imaging quality of the system is improved; at the same time, the spacer element can not be too thin or too thick, thereby ensuring the strength of the spacer element and the size of the lens structure diameter under the premise of a certain body height.

[0050] In the example embodiment, the visual system of the present application can further include a first spacing element located on the second side of the first lens and partially in contact with the second side surface of the first lens, and the visual system can satisfy the condition formula 0 < (Vr x dr + Vp x dp) / (EP12 - dr - dp) < 15, wherein Vr is the Abbe number of the reflective polarizing element, dr is the central thickness of the reflective polarizing element on the optical axis, Vp is the Abbe number of the quarter-wave plate, dp is the central thickness of the quarter-wave plate on the optical axis, and EP12 is the distance from the second side surface of the first spacing element to the first side surface of the second spacing element on the optical axis. By controlling the Abbe number of the reflective polarizing element, the central thickness of the reflective polarizing element on the optical axis, the Abbe number of the quarter-wave plate, the central thickness of the quarter-wave plate on the optical axis, and the distance from the second side surface of the first spacing element to the first side surface of the second spacing element on the optical axis to satisfy the condition formula 0 < (Vr x dr + Vp x dp) / (EP12 - dr - dp) < 15, the occurrence of axial chromatic aberration can be effectively reduced, the clear imaging of the entire visual system can be facilitated, and the achromatic effect of the entire visual system can be ensured. The lens group stability and the required thickness ratio of the formed lens can also be ensured, and the polarizing sheet and the wave plate have a certain central thickness, which can facilitate the matching of the film pasting process.

[0051] In the example embodiment, the visual system of the present application can further include a first spacing element located on the second side of the first lens and partially in contact with the second side surface of the first lens, and the visual system can satisfy the condition formula -3 < (D0s - d1s) / (CT2 + T23 - CT3) < 8, wherein D0s is the outer diameter of the first side end surface of the lens barrel, d1s is the inner diameter of the first side surface of the first spacing element, CT2 is the central thickness of the second lens on the optical axis, T23 is the spacing distance of the second lens and the third lens on the optical axis, and CT3 is the central thickness of the third lens on the optical axis. By controlling the outer diameter of the first side end surface of the lens barrel, the inner diameter of the first side surface of the first spacing element, the central thickness of the second lens on the optical axis, the spacing distance of the second lens and the third lens on the optical axis, and the central thickness of the third lens on the optical axis to satisfy the condition formula -3 < (D0s - d1s) / (CT2 + T23 - CT3) < 8, the central thickness of the second and third lenses can be constrained within a reasonable range, and the phenomenon of excessively protruding towards the display can be avoided. At the same time, the radial size and height of the visual system after assembly can be coordinated, the wall thickness of the entire lens barrel can be uniform, the molding shrinkage can be uniform, and the lens barrel fitting precision can be improved.

[0052] In the exemplary embodiments, the visual system of the present application can further include a first spacer element located on the second side of the first lens and in partial contact with the second side surface of the first lens, and the visual system can satisfy the condition formula 0mm < R2 / R3 x EP12 < 15mm, wherein R2 is the radius of curvature of the second side surface of the first lens, R3 is the radius of curvature of the first side surface of the second lens, and EP12 is the spacing distance between the first spacer element and the second spacer element, i.e. the distance on the optical axis from the second side surface of the first spacer element to the first side surface of the second spacer element. By controlling the radius of curvature of the second side surface of the first lens, the radius of curvature of the first side surface of the second lens, and the spacing distance between the first spacer element and the second spacer element to satisfy the condition formula 0mm < R2 / R3 x EP12 < 15mm, the optical power of the first and second lenses can be reasonably controlled, thereby facilitating system aberration correction, such as field curvature, astigmatism, etc.; at the same time, the flange thickness of the lens between the two spacer elements can be ensured to be within a reasonable range, so as to facilitate the stability of the lens forming process.

[0053] In the exemplary embodiments, the quarter-wave plate can be attached to the reflective polarizing element, and the reflective polarizing element can be attached to the second side surface of the first lens. More specifically, the first side surface of the quarter-wave plate can be attached to the second side surface of the reflective polarizing element, and the first side surface of the reflective polarizing element can be attached to the second side surface of the first lens. That is, the first lens, the reflective polarizing element, and the quarter-wave plate can be sequentially arranged along the optical axis from the first side to the second side.

[0054] Figure 20 A diagram showing the propagation path of light rays through the visual system of the exemplary embodiments of the present application is shown. Figure 21 is Figure 20 a partial enlarged view of Figure 20 and Figure 21As shown, the optical system according to the exemplary embodiments of the present application can include a first lens L1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens L2 and a third lens L3 arranged in sequence from a first side to a second side. In actual use, the optical system according to the exemplary embodiments of the present application can be used as a VR lens, in which case the first side corresponds to the side of the human eye and the second side corresponds to the side of the display. The optical system can further include an image plane IMG located on the side of the display. A light beam emitted from the image plane IMG passes through the third lens L3, the second lens L2 and the quarter wave plate QWP in sequence to reach the reflective polarizing element RP, is reflected at the reflective polarizing element RP and passes through the quarter wave plate QWP, the second lens L2 and the third lens L3 again to reach the second side surface of the third lens L3, is reflected again at the second side surface of the third lens L3 and passes through the third lens L3, the second lens L2, the quarter wave plate QWP, the reflective polarizing element RP and the first lens L1 in sequence to exit towards the side of the human eye. In the exemplary embodiments, the second side surface of the third lens L3 can be provided with a partial reflection element, which can be, for example, a semi-transparent and semi-reflective film layer coated on the second side surface of the third lens L3.

[0055] In the exemplary embodiments, the visual system of the present application can satisfy the condition formula 0<|F3| / (D0m-d2m)<40, where F3 is the effective focal length of the third element group, D0m is the outer diameter of the second side end surface of the barrel, and d2m is the inner diameter of the second side surface of the second spacer element. By controlling the effective focal length of the third element group, the outer diameter of the second side end surface of the barrel and the inner diameter of the second side surface of the second spacer element to satisfy the condition formula 0<|F3| / (D0m-d2m)<40, the aberration of the visual system can be corrected; the full passage of light through the inner diameter edge of the spacer element can be ensured to meet the requirement for the realization of the maximum FOV, and the uniform wall thickness of the barrel can be ensured to facilitate uniform shrinkage during molding and demolding.

[0056] In the exemplary embodiments, the visual system of the present application can further include a first spacer element located on the second side of the first lens and partially in contact with the second side surface of the first lens, and the visual system can satisfy the condition formula 0<|F2 / (d2s+d1m)|<8, where F2 is the effective focal length of the second element group, d2s is the inner diameter of the first side surface of the second spacer element, and d1m is the inner diameter of the second side surface of the first spacer element. By controlling the effective focal length of the second element group, the inner diameter of the first side surface of the second spacer element, and the inner diameter of the second side surface of the first spacer element to satisfy the condition formula 0<|F2 / (d2s+d1m)|<8, the focal length of the second lens element can function as a relay lens for the first and third lens elements, the overall focal length of the system can meet the design requirements, the optical power of the three lens groups can be reasonably distributed, the positive and negative optical powers of the lenses can be matched, the optical aberrations can be balanced, and the imaging quality of the system can be improved; at the same time, the light rays can be ensured to be non-vignetted, and the spacer element can have a reasonable size to be stably supported by the lens flange surface.

[0057] In the exemplary embodiments, the visual system of the present application can include at least one diaphragm. The diaphragm can restrict the light path and control the light intensity. The diaphragm can be arranged at a suitable position of the visual system as needed, for example, the diaphragm can be arranged between the first side (the human eye side) and the first lens.

[0058] In the exemplary embodiments, the visual system described above can further include a filter for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the imaging surface.

[0059] According to the visual system of the above-described embodiments of the present application, by arranging the first element group, the second element group, and the third element group in the lens barrel in sequence from the first side to the second side along the optical axis, wherein the first element group includes the first lens, the reflective polarizing element, and the quarter-wave plate; the second element group includes the second lens; the third element group includes the third lens; and the air gap of the second lens and the third lens on the optical axis is smaller than the air gap of other adjacent lenses on the optical axis; and the second spacer element is arranged on the second side of the second lens and partially in contact with the second side surface of the second lens; and controlling the effective focal length F2 of the second element group, the effective focal length F3 of the third element group, the outer diameter D2m of the second side surface of the second spacer element, and the inner diameter d2s of the first side surface of the second spacer element to satisfy the condition formula -8<(F2+F3) / (D2m+d2s)<0, the shape of the second lens and the third lens can be reasonably controlled, the light rays can be ensured to converge on the display, the optical back focal length can be ensured not to be too long, the visual system can be ensured to be compact, the air gap between the lenses can be reduced, the occurrence of aberration phenomena such as field curvature and chromatic aberration can be reduced, the system clarity and color restoration requirements can be ensured, and the assembly surface can have sufficient supporting area to ensure stability during assembly.

[0060] The visual system according to the example embodiments of the present application has the characteristics of being light and thin, high performance, and easy to manufacture, and can provide better comprehensive visual perception and use experience for users, and can also reduce production cost and improve production efficiency.

[0061] The specific embodiments of the visual system applicable to the above embodiments are further described below with reference to the accompanying drawings.

[0062] Example 1

[0063] The visual system according to the example embodiments of the present application has the characteristics of being light and thin, high performance, and easy to manufacture, and can provide better comprehensive visual perception and use experience for users, and can also reduce production cost and improve production efficiency. Figure 2 、 Figure 3 、 Figure 4 and Figure 5 、 Figure 6 and Figure 7 The visual system according to the example embodiments of the present application has the characteristics of being light and thin, high performance, and easy to manufacture, and can provide better comprehensive visual perception and use experience for users, and can also reduce production cost and improve production efficiency. Figure 2 、 Figure 3 and Figure 4 respectively show the structural schematic diagram of the visual system according to the example 1 of the present application under three different embodiments (embodiment 1-1, embodiment 1-2, embodiment 1-3).

[0064] As shown in Figure 2 、 Figure 3 and Figure 4 , the visual system includes a lens barrel P0 and, sequentially arranged along the optical axis from the first side (the side of the human eye) to the second side (the side of the display) in the lens barrel P0: a first lens L1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens L2 and a third lens L3.

[0065] In this embodiment, the first lens L1, the reflective polarizing element RP and the quarter-wave plate QWP can constitute a first element group, specifically, the first side surface (the surface close to the human eye side and away from the display side) of the quarter-wave plate QWP is attached to the second side surface (the surface close to the display side and away from the human eye side) of the reflective polarizing element RP, and the first side surface (the surface close to the human eye side and away from the display side) of the reflective polarizing element RP is attached to the second side surface (the surface close to the display side and away from the human eye side) of the first lens L1.

[0066] In this embodiment, the visual system further includes a first spacing element P1 located between the first lens L1 and the second lens L2, and the first spacing element P1 is partially in contact with the second side surface (the surface close to the display side and away from the human eye side) of the first lens L1; and a second spacing element P2 located between the second lens L2 and the third lens L3, and the second spacing element P2 is partially in contact with the second side surface (the surface close to the display side and away from the human eye side) of the second lens L2.

[0067] Table 1 shows the basic parameters of the visual system of Example 1, wherein the units of the radius of curvature and the thickness / distance are millimeters (mm).

[0068]

[0069] Table 1

[0070] In Example 1, the first side surface S1 of the first lens L1, the second side surface S2 of the first lens L1, the first side surface S5 of the second lens L2, the second side surface S6 of the second lens L2, and the first side surface S7 of the third lens L3, the second side surface S8 of the third lens L3 are all aspherical surfaces, and the surface types of the respective aspherical lenses are The following aspherical formula can be used, but is not limited to, for the definition:

[0071] (1)

[0072] wherein, is the sag of the aspherical surface at a position with a height of h from the vertex of the aspherical surface along the optical axis; c is the paraxial curvature of the aspherical surface, c =1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the correction coefficient of the aspherical surface of the i -th order. Table 2 below shows the high-order term coefficients that can be used for the respective aspherical mirrors S1 to S2, S5 to S8 in Example 1 A 4 , A 6 , A 8 , A 10 and A 12 .

[0073]

[0074] Table 2

[0075] The relevant parameter values in this example are shown in Table 7, in combination with Figure 2 , Figure 3 , Figure 4 and Figure 1wherein d1s is the inner diameter of the first side surface of the first spacer element P1; d1m is the inner diameter of the second side surface of the first spacer element P1; d2s is the inner diameter of the first side surface of the second spacer element P2; d2m is the inner diameter of the second side surface of the second spacer element P2; D2s is the outer diameter of the first side surface of the second spacer element P2; D2m is the outer diameter of the second side surface of the second spacer element P2; d0m is the inner diameter of the second side end surface of the lens barrel P0; D0s is the outer diameter of the first side end surface of the lens barrel P0; D0m is the outer diameter of the second side end surface of the lens barrel P0; EP01 is the distance on the optical axis from the first side end surface of the lens barrel P0 to the first side surface of the first spacer element P1; CP1 is the thickness of the first spacer element P1 along the direction parallel to the optical axis; EP12 is the distance on the optical axis from the second side surface of the first spacer element P1 to the first side surface of the second spacer element P2; CP2 is the thickness of the second spacer element P2 along the direction parallel to the optical axis; EP02 is the distance on the optical axis from the first side end surface of the lens barrel P0 to the first side surface of the second spacer element P2; and L is the maximum height of the lens barrel P0 along the direction of the optical axis. The units of the above parameters shown in Table 7 are millimeters (mm).

[0076] Figure 5 The on-axis chromatic aberration curve of the visual system of Example 1 is shown, which represents the deviation of the convergent focus points of light rays of different wavelengths after passing through the lens. Figure 6 The astigmatism curve of the visual system of Example 1 is shown, which represents the meridional image surface curvature and sagittal image surface curvature. Figure 7 The distortion curve of the visual system of Example 1 is shown, which represents the distortion size values corresponding to different field angles. According to the distortion curve, the distortion size values of the visual system of Example 1 are less than 0.1% at different field angles. Figure 5 to Figure 7 It can be seen that the visual system given in Example 1 can achieve good imaging quality.

[0077] Example 2

[0078] The visual system according to Example 2 of the present application is described below with reference to Figure 8 , Figure 9 , Figure 10 and Figure 11 , Figure 12 and Figure 13 . In this embodiment and the following embodiments, for the sake of brevity, some descriptions similar to Example 1 will be omitted. Figure 8 , Figure 9 and Figure 10 respectively show the structural schematic diagrams of the visual system according to Example 2 of the present application under three different implementation manners (implementation manner 2-1, implementation manner 2-2, implementation manner 2-3).

[0079] As Figure 8 , Figure 9 and Figure 10As shown, the visual system includes a lens barrel P0, and sequentially arranged along the optical axis from the first side (the human eye side) to the second side (the display side) in the lens barrel P0: a first lens L1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens L2, and a third lens L3.

[0080] In this embodiment, the first lens L1, the reflective polarizing element RP, and the quarter-wave plate QWP can constitute a first element group, specifically, the first side (the surface close to the human eye side and away from the display side) of the quarter-wave plate QWP is attached to the second side (the surface close to the display side and away from the human eye side) of the reflective polarizing element RP, and the first side (the surface close to the human eye side and away from the display side) of the reflective polarizing element RP is attached to the second side (the surface close to the display side and away from the human eye side) of the first lens L1.

[0081] In this embodiment, the visual system further includes a first spacing element P1 located between the first lens L1 and the second lens L2, the first spacing element P1 being in partial contact with the second side (the surface close to the display side and away from the human eye side) of the first lens L1; and a second spacing element P2 located between the second lens L2 and the third lens L3, the second spacing element P2 being in partial contact with the second side (the surface close to the display side and away from the human eye side) of the second lens L2.

[0082] Table 3 shows the basic parameters of the visual system of embodiment 2, wherein the units of the radius of curvature and the thickness / distance are millimeters (mm). In this embodiment, the first side S1, the second side S2 of the first lens L1, and the first side S5, the second side S6 of the second lens L2, and the first side S7, the second side S8 of the third lens L3 are aspherical surfaces, and Table 4 shows the high-order term coefficients of the aspherical surfaces S1-S2, S5-S8 that can be used in embodiment 2 A 4 、 A 6 、 A 8 、 A 10 and A 12 wherein each aspherical surface can be defined by the formula (1) given in embodiment 1 above.

[0083]

[0084] Table 3

[0085]

[0086] Table 4

[0087] The values of the relevant parameters in Example 2 are shown in Table 7, respectively, where the meanings of the parameters are as described above, and the units of the parameters shown in Table 7 are millimeters (mm).

[0088] Figure 11 The on-axis chromatic aberration curve of the visual system of Example 2 is shown, which represents the deviation of the converging focus point of light rays of different wavelengths after passing through the lens. Figure 12 The astigmatism curve of the visual system of Example 2 is shown, which represents the meridional image curvature and sagittal image curvature. Figure 13 The distortion curve of the visual system of Example 2 is shown, which represents the distortion size values corresponding to different field angles. According to the distortion curve, the distortion size values corresponding to different field angles are as follows: Figure 11 to Figure 13 It can be seen that the visual system given in Example 2 can achieve good imaging quality.

[0089] Example 3

[0090] The visual system according to Example 3 of the present application is described below with reference to Figure 14 , Figure 15 , Figure 16 and Figure 17 , Figure 18 and Figure 19 . Figure 14 , Figure 15 and Figure 16 respectively show the structural schematic diagrams of the visual system according to Example 3 of the present application in three different embodiments (Embodiment 3-1, Embodiment 3-2, Embodiment 3-3).

[0091] As shown in Figure 14 , Figure 15 and Figure 16 , the visual system comprises a lens barrel P0 and, arranged in the lens barrel P0 in order from the first side (the side of the human eye) to the second side (the side of the display) along the optical axis: a first lens L1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens L2 and a third lens L3.

[0092] In this embodiment, the first lens L1, the reflective polarizing element RP and the quarter-wave plate QWP can constitute a first element group, specifically, the first side surface (the surface close to the side of the human eye and away from the side of the display) of the quarter-wave plate QWP is attached to the second side surface (the surface close to the side of the display and away from the side of the human eye) of the reflective polarizing element RP, and the first side surface (the surface close to the side of the human eye and away from the side of the display) of the reflective polarizing element RP is attached to the second side surface (the surface close to the side of the display and away from the side of the human eye) of the first lens L1.

[0093] In this embodiment, the visual system further includes a first spacer element P1 located between the first lens L1 and the second lens L2, the first spacer element P1 partially contacting the second side surface (the surface near the display side and away from the human eye) of the first lens L1; and a second spacer element P2 located between the second lens L2 and the third lens L3, the second spacer element P2 partially contacting the second side surface (the surface near the display side and away from the human eye) of the second lens L2.

[0094] Table 5 shows the basic parameters of the visual system in Embodiment 3, where the units for radius of curvature and thickness / distance are millimeters (mm). In this embodiment, the first side surface S1, the second side surface S2 of the first lens L1, the first side surface S5 and the second side surface S6 of the second lens L2, and the first side surface S7 and the second side surface S8 of the third lens L3 are all aspherical surfaces. Table 6 shows the higher-order coefficients of the aspherical mirrors S1 to S2 and S5 to S8 that can be used in Embodiment 3. A 4 , A 6 , A 8 , A 10 and A 12 Each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0095]

[0096] Table 5

[0097]

[0098] Table 6

[0099] The relevant parameter values ​​in Example 3 are shown in Table 7. The meaning of each parameter is as described above and will not be repeated here. The unit of each parameter in Table 7 is millimeters (mm).

[0100] Figure 17 The on-axis chromatic aberration curve of the visual system of Embodiment 3 is shown, which represents the deviation of the convergence focal point of light of different wavelengths after passing through the lens. Figure 18 The astigmatic curves of the visual system of Embodiment 3 are shown, representing the meridional image plane curvature and the sagittal image plane curvature. Figure 19 The distortion curves of the visual system in Example 3 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. According to... Figure 17 to Figure 19 It can be seen that the visual system given in Example 3 can achieve good imaging quality.

[0101]

[0102] Table 7

[0103] Further, in Embodiment 1 to Embodiment 3, the effective focal length f of the visual system, the aperture value Fno of the visual system, the effective focal length Fl of the first element group, the effective focal length F2 of the second element group, the effective focal length F3 of the third element group, the central thickness dr of the reflective polarizing element on the optical axis, and the central thickness dp of the quarter-wave plate on the optical axis are as shown in Table 8.

[0104]

[0105] Table 8

[0106] Embodiment 1 to Embodiment 3 respectively satisfy the conditions shown in Table 9.

[0107]

[0108] Table 9

[0109] The present application also provides an imaging device provided with an electronic photosensitive element to image, which can be a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS). The imaging device can be a stand-alone imaging apparatus such as a digital camera, or an imaging module integrated on a mobile electronic device such as a mobile phone. The imaging device is equipped with the visual system described above.

[0110] The above description is merely preferred embodiments of the present application and a description of the principles of the technology used. Those skilled in the art should understand that the scope of protection involved in the present application is not limited to the technical solutions formed by the specific combinations of the technical features described above, and should also cover other technical solutions formed by any combinations of the technical features described above or their equivalent features without departing from the concept of the present application. For example, the technical solutions formed by mutually replacing the above-described features and the technical features disclosed in the present application (but not limited to) having similar functions.

Claims

1. Vision system, characterized in that The visual system comprises a lens barrel and a first element group, a second element group and a third element group arranged sequentially along an optical axis from a first side to a second side in the lens barrel, wherein The first element group comprises a first lens, a reflective polarizing element and a quarter wave plate; The second element group comprises a second lens; The third element group comprises a third lens, and the second side surface of the third lens is a convex surface; An air gap of the second lens and the third lens on the optical axis is less than an air gap of the first lens and the second lens on the optical axis; The visual system further comprises a first spacer element and a second spacer element, the first spacer element is located on the second side of the first lens and partially contacts the second side surface of the first lens, and the second spacer element is located on the second side of the second lens and partially contacts the second side surface of the second lens; and The visual system satisfies 2.1843≤|F1 / d1s|≤22.8584, -4.4724≤(F2+F3) / (D2m+d2s)≤-0.9781 and 1.8452≤|F2 / (d2s+d1m)|≤5.4515, Wherein, F1 is an effective focal length of the first element group, d1s is an inner diameter of a first side surface of the first spacer element, F2 is an effective focal length of the second element group, F3 is an effective focal length of the third element group, D2m is an outer diameter of a second side surface of the second spacer element, d2s is an inner diameter of a first side surface of the second spacer element, and d1m is an inner diameter of a second side surface of the first spacer element; The first side is an eye side, and the second side is a display side; The number of lenses with optical power in the visual system is three; The visual system further comprises a partial reflection layer arranged on the second side surface of the third lens; The quarter wave plate is attached to the reflective polarizing element, and the reflective polarizing element is attached to the second side surface of the first lens; The first lens has positive optical power, and the second lens and the third lens have opposite positive and negative properties of optical power; or the first lens and the second lens both have negative optical power, and the third lens has positive optical power.

2. The vision system of claim 1, wherein, 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 outer diameter D2s of the first side surface of the second spacer element satisfy: 0.0469≤|R5-R4| / (D2m+D2s)≤44.7956.

3. The vision system of claim 1, wherein, The radius of curvature R6 of the second side surface of the third lens, the inner diameter d0m of the second side end surface of the lens barrel and the aperture value Fno of the visual system satisfy: -6.8078≤R6 / d0m×Fno≤-2.8001.

4. The vision system of claim 1, wherein, The center thickness CT3 of the third lens on the optical axis, the maximum height L of the lens barrel along the optical axis direction and the distance EP02 from the first side end surface of the lens barrel to the first side surface of the second spacer element on the optical axis satisfy: 0.6466≤CT3 / (L-EP02)≤2.0281.

5. The vision system of claim 1, wherein, The refractive index N1 of the first lens, the refractive index N2 of the second lens, the refractive index Nr of the reflective polarizing element, the refractive index Np of the quarter-wave plate, the distance EP02 on the optical axis from the first side end surface of the lens barrel to the first side surface of the second spacer element, and the distance EP01 on the optical axis from the first side end surface of the lens barrel to the first side surface of the first spacer element satisfy: 1.3509 ≤ (N1 + N2 + Nr + Np) / (EP02 - EP01) ≤ 5.1544.

6. The vision system of claim 1, wherein, The effective focal length F1 of the first element group, the thickness CP1 of the first spacer element in the direction parallel to the optical axis, the thickness CP2 of the second spacer element in the direction parallel to the optical axis, the central thickness CT3 of the third lens on the optical axis, and the effective focal length f of the visual system satisfy: 21.9432 mm ≤ |F1 × CP1 + F2 × CP2 + F3 × CT3| / f ≤ 83.807 mm.

7. The vision system of claim 1, wherein, The Abbe number Vr of the reflective polarizing element, the central thickness dr of the reflective polarizing element on the optical axis, the Abbe number Vp of the quarter-wave plate, the central thickness dp of the quarter-wave plate on the optical axis, and the distance EP12 on the optical axis from the second side surface of the first spacer element to the first side surface of the second spacer element satisfy: 3.9302 ≤ (Vr × dr + Vp × dp) / (EP12 - dr - dp) ≤ 12.9252.

8. The vision system of claim 1, wherein, The outer diameter D0s of the first side end surface of the lens barrel, the inner diameter d1s of the first side surface of the first spacer element, the central thickness CT2 of the second lens on the optical axis, the interval distance T23 on the optical axis between the second lens and the third lens, and the central thickness CT3 of the third lens on the optical axis satisfy: -2.0784 ≤ (D0s - d1s) / (CT2 + T23 - CT3) ≤ 5.3766.

9. The vision system of claim 1, wherein, The radius of curvature R2 of the second side surface of the first lens, the radius of curvature R3 of the first side surface of the second lens, and the distance EP12 on the optical axis from the second side surface of the first spacer element to the first side surface of the second spacer element satisfy: 1.0173 mm ≤ R2 / R3 × EP12 ≤ 10.4748 mm.

10. The vision system of any one of claims 1 to 9, wherein, The outer diameter D0m of the second side end surface of the lens barrel and the inner diameter d2m of the second side surface of the second spacer element satisfy: 6.2709 ≤ |F3| / (D0m - d2m) ≤ 34.2402.

11. A VR device including the visual system according to any one of claims 1 to 10.

Images