Eyepiece imaging system

Abstract

The invention discloses an eyepiece imaging system, which comprises a lens barrel, a first lens group, a second lens group, a third lens group, a plurality of bearing elements and a light source, the first lens group comprises a first lens; the second lens group comprises a second lens; the third lens group comprises a third lens; the first lens, the second lens and the third lens are sequentially arranged from the outer side to the inner side along the optical axis. The plurality of bearing elements includes a first bearing element and a second bearing element. Wherein the back focus FL of the eyepiece imaging system and the inner diameter d0m of the inner side surface of the lens barrel meet the following conditions: 8.5 lt; d0 m / FLlt; 9.5. By controlling the back focus of the optical imaging system, the field angle of the system is effectively restrained, so that the system meets the characteristic of large field of view of the eyepiece.

Description

[0001] This application is a divisional application with application number 202310694932.X. The application date of the parent case is: June 12, 2023; the name of the invention of the parent case is: an eyepiece imaging lens. Technical Field

[0002] The present application belongs to the field of optics, and in particular to an eyepiece imaging system. Background Art

[0003] Since the concept of "metaverse" was proposed, AR / VR has ushered in a second opportunity for development. As the entrance to human-computer interaction, VR imaging lenses play an important role. On the one hand, the imaging quality of VR imaging lenses needs to meet the resolution requirements of the human eye; on the other hand, the early aspherical or Fresnel lenses have a long body, and when worn on the head, the center of gravity is forward, which makes the user experience poor and urgently needs to be improved.

[0004] Based on the above needs, a folded optical path solution has been proposed. By folding the optical path, the length of the lens body is compressed to half of the original length, thereby moving the center of gravity of the head-mounted device backward and improving the consumer experience. At present, a two-piece folded optical path device based on optical path folding has been released. From the user experience point of view, its external field of view is relatively blurry, and the imaging quality of the two-piece lens needs to be improved. This patent designs a three-piece folded optical path solution and adopts a flat-attached one-piece composite film design, which can better compress the body height and improve the imaging quality. Summary of the invention

[0005] The present application aims to provide an eyepiece imaging system that adopts a three-piece folded optical path solution to reduce the thickness of the VR system, solve the problem of poor imaging in the edge field of view, reduce dizziness, and enhance the consumer experience.

[0006] The present application provides an eyepiece imaging system, which includes: a lens barrel, a first lens group, a second lens group, a third lens group, a plurality of supporting elements and a light source;

[0007] The first lens group includes a first lens;

[0008] The second lens group includes a second lens;

[0009] The third lens group includes a third lens;

[0010] The first lens, the second lens and the third lens are arranged in sequence from the outside to the inside along the optical axis; each of the first lens to the third lens has at least one outer side surface away from the light source and one inner side surface close to the light source;

[0011] The plurality of supporting elements include a first supporting element and a second supporting element;

[0012] The first supporting element comprises at least one outer side surface away from the light source and an inner side surface close to the light source, the first supporting element is placed between the first lens and the second lens, and its outer side surface is closest to the first lens along the optical axis direction compared to the outer side surfaces of other supporting elements;

[0013] The second supporting element comprises at least one outer side surface away from the light source and an inner side surface close to the light source, the second supporting element is placed between the second lens and the third lens, and its outer side surface is closest to the second lens along the optical axis direction compared to the outer side surfaces of other supporting elements;

[0014] Wherein, the back focus FL of the eyepiece imaging system and the inner diameter d0m of the inner side of the lens barrel satisfy: 8.5 <d0m / FL<9.5。

[0015] According to an embodiment provided by the present application, the eyepiece imaging system further includes a reflective polarizing element and a quarter-wave plate;

[0016] The reflective polarizing element and the quarter wave plate are located in the first lens group, and the reflective polarizing element and the quarter wave plate are attached to the outer side surface of the first lens;

[0017] The outer side surface of the third lens has a partial reflection layer.

[0018] According to an embodiment provided by the present application, the entrance pupil diameter EPD of the eyepiece imaging system, the outer diameter D0s of the outer side of the lens barrel, and the inner diameter d0s of the outer side of the lens barrel satisfy: 50 mm <EPD×(D0s+d0s) / (D0s-d0s)<85mm。

[0019] According to an embodiment provided by the present application, the effective focal length f2 of the second lens, the outer diameter D2m of the inner side surface of the second supporting element and the inner diameter d2m of the inner side surface of the second supporting element satisfy: 1 <f2^2 / (π×(D2m^2-d2m^2))<3。

[0020] According to an embodiment provided in the present application, the inner diameter d2m of the inner side surface of the second supporting element, the curvature radius R5 of the outer side surface of the third lens, and the curvature radius R6 of the inner side surface of the third lens satisfy: -4.5<(R5+R6) / d2m<-3.

[0021] According to an embodiment provided by the present application, the refractive index N2 of the second lens, the maximum thickness CP2 of the second supporting element, and the distance T23 between the second lens and the third lens on the optical axis satisfy: 1 <CP2 / T23×N2<37。

[0022] According to an embodiment provided by the present application, the dispersion coefficient V1 of the first lens, the effective focal length f1 of the first lens, and the inner diameter d1m of the inner side surface of the first supporting element satisfy: -65 <V1×f1 / d1m<-62。

[0023] According to an embodiment provided by the present application, the dispersion coefficient V2 of the second lens, the inner diameter d2s of the outer side surface of the second supporting element, and the effective focal length f2 of the second lens satisfy: 73 <V2×f2 / d2s<82。

[0024] According to an embodiment provided in the present application, the distance EP12 between the first supporting element and the second supporting element in the horizontal direction, the distance EP01 between the lens barrel and the first supporting element in the horizontal direction, and the maximum length L of the lens barrel satisfy: 0.5<(EP01+EP12) / L<0.6.

[0025] According to an embodiment provided by the present application, the thickness CT2 of the second lens on the optical axis is equal to the maximum thickness CP2 of the second supporting element, and the maximum thickness CP1 of the first supporting element satisfies: 0.1 <CP1+CP2 / CT2<0.5。

[0026] According to an embodiment provided by the present application, half of the maximum field of view of the eyepiece imaging system, semi-FOV, the maximum length L of the lens barrel, the outer diameter D0m of the inner side of the lens barrel, and the outer diameter D0s of the outer side of the lens barrel satisfy the following conditions: 2.5 <TAN(semi-FOV)×L / (D0m-D0s)<5.5。

[0027] According to an embodiment provided in the present application, the focal length f1 of the first lens, the inner diameter d1m of the inner surface of the first supporting element, and the outer diameter D1m of the inner surface of the first supporting element satisfy: 29<|f1 / (D1m-d1m)|<39.

[0028] According to an implementation manner provided by the present application, the first lens and the second lens have opposite refractive powers.

[0029] According to an embodiment provided by the present application, the visible light reflectivity of at least one supporting element is less than 15%.

[0030] Beneficial effects of this application:

[0031] The eyepiece imaging system provided by the present application includes multiple lenses, such as the first lens to the third lens. A first supporting element and a second supporting element are provided between adjacent lenses. By reasonably setting the effective focal length of the second lens and the inner and outer diameters of the second supporting element, the shape of the second lens is effectively controlled, and the difficulty of forming the second lens is reduced. At the same time, the supporting elements are supported by the inner wall of the lens barrel, and the straight position size is reasonably controlled, and the requirements for the linear contour line of the matching part of the lens barrel and the supporting element are reduced, thereby reducing the difficulty of the lens assembly process and improving the assembly process yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 This is a schematic diagram of the structure of the eyepiece imaging system of this application;

[0034] Figure 2 This is a schematic diagram of the structure of the eyepiece imaging system of Example 1;

[0035] Figure 3 This is a schematic diagram of the structure of the eyepiece imaging system of Example 1;

[0036] Figure 4 This is a schematic diagram of the structure of the eyepiece imaging system of Example 1;

[0037] Figure 5a to Figure 5d They are respectively the axial chromatic aberration curve, astigmatism curve, distortion curve and relative illumination curve of Example 1 of the eyepiece imaging system of the present application;

[0038] Figure 6 Schematic diagram of the structure of the eyepiece imaging system of Example 2;

[0039] Figure 7 Schematic diagram of the structure of the eyepiece imaging system of Example 2;

[0040] Figure 8 This is a schematic diagram of the structure of the eyepiece imaging system of Example 1;

[0041] Figures 9a to 9d They are respectively the axial chromatic aberration curve, astigmatism curve, distortion curve and relative illumination curve of Example 2 of the eyepiece imaging system of the present application;

[0042] Fig.10 This is a schematic diagram of the structure of the eyepiece imaging system of Example 3;

[0043] Fig.11This is a schematic diagram of the structure of the eyepiece imaging system of Example 3;

[0044] Fig.12 This is a schematic diagram of the structure of the eyepiece imaging system of Example 3;

[0045] Figures 13a to 13d They are respectively the axial chromatic aberration curve, the astigmatism curve, the distortion curve and the relative illumination curve of Example 3 of the eyepiece imaging system of the present application; DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0047] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0048] It should also be understood that the terms "comprises", "including", "having", "includes" and / or "comprising", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0049] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0050] In the description of the present application, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region. If the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object being photographed is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

[0051] 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 should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formal manner unless expressly so defined herein.

[0052] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The features, principles, and other aspects of the present application will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0053] Exemplary embodiments

[0054] Reference Figure 1 As shown, the exemplary eyepiece imaging system of the present application includes: a barrel, a first lens group, a second lens group, a third lens group, a plurality of supporting elements, and a light source; the first lens group includes a first lens; the second lens group includes a second lens; the third lens group includes a third lens; the first lens, the second lens, and the third lens are arranged in sequence along the optical axis from the outside to the inside; each of the first lens to the third lens has at least one outer side surface away from the light source and an inner side surface close to the light source; the plurality of supporting elements include a first supporting element and a second supporting element; the first supporting element includes at least one outer side surface away from the light source and an inner side surface close to the light source, the first supporting element is placed between the first lens and the second lens and its outer side surface is closest to the first lens along the optical axis direction compared with the outer side surfaces of other supporting elements; the second supporting element includes at least one outer side surface away from the light source and an inner side surface close to the light source, the second supporting element is placed between the second lens and the third lens and its outer side surface is closest to the second lens along the optical axis direction compared with the outer side surfaces of other supporting elements; wherein, for the back focal length FL of the eyepiece imaging system, the inner diameter d0m of the inner side surface of the barrel satisfies: 8.5 < d0m / FL < 9.5. By controlling the back focal length of the optical imaging system, the field of view angle of the system is effectively constrained, so that the system meets the characteristics of a large field of view of the eyepiece. More specifically, for the back focal length FL of the eyepiece imaging system, the inner diameter d0m of the inner side surface of the barrel satisfies: 8.9 < d0m / FL < 9.2.

[0055] In an exemplary embodiment of the present application, the reflective polarizing element and the quarter-wave plate are located in the first lens group, and the reflective polarizing element and the quarter-wave plate are attached to the outer side surface of the first lens; a partial reflection layer is provided on the outer side surface of the third lens. By placing the reflective polarizing element and the quarter-wave plate on the first lens and attaching them to the outer side surface of the first lens, the folding effect of the imaging optical path is achieved by utilizing the phase addition function of the quarter-wave plate for polarized light and the light splitting function of the reflective polarizing element, as well as the reflection function of the partial reflection layer in the third lens; both the reflective polarizing element and the quarter-wave plate are attached to the outer side surface of the first lens, which can combine the reflective polarizing element and the quarter-wave plate, and the required structure can be obtained through a single attachment process instead of two, reducing the angular position error caused by attachment and improving the imaging quality.

[0056] In an exemplary embodiment of the present application, the entrance pupil diameter EPD of the eyepiece imaging system, the outer diameter D0s of the outer side surface of the lens barrel, and the inner diameter d0s of the outer side surface of the lens barrel satisfy: 50 mm < EPD×(D0s + d0s) / (D0s - d0s) < 85 mm. By controlling the entrance pupil diameter of the optical system to meet ergonomics, it is beneficial to the immersive experience of the VR lens; at the same time, by controlling the outer diameter of the lens, on the one hand, the size of the lens barrel is minimized, thereby reducing the overall size of the machine; on the other hand, a certain ratio is maintained between the diameter of the lens barrel and the diameter of the lens, and the uniform wall thickness of the lens barrel is beneficial to stabilizing the reliability of the lens. More specifically, the entrance pupil diameter EPD of the eyepiece imaging system, the outer diameter D0s of the outer side surface of the lens barrel, and the inner diameter d0s of the outer side surface of the lens barrel satisfy: 54 mm < EPD×(D0s + d0s) / (D0s - d0s) < 84 mm.

[0057] In an exemplary embodiment of the present application, the effective focal length f2 of the second lens, the outer diameter D2m of the inner side surface of the second supporting element, and the inner diameter d2m of the inner side surface of the second supporting element satisfy: 1 < f2^2 / (π×(D2m^2 - d2m^2)) < 3. The three-piece eyepiece imaging system is provided with a first supporting element and a second supporting element between adjacent lenses. By reasonably setting the effective focal length of the second lens and the inner and outer diameters of the second supporting element, the shape of the second lens is effectively controlled, the forming difficulty of the second lens is reduced, and at the same time, the supporting elements are all partially supported on the inner wall of the lens barrel, the straight position dimensions are reasonably controlled, the line profile requirements of the matching part between the lens barrel and the supporting element are reduced, the lens assembly process difficulty is reduced, and the yield rate of the assembly process is improved. More specifically, the effective focal length f2 of the second lens, the outer diameter D2m of the inner side surface of the second supporting element, and the inner diameter d2m of the inner side surface of the second supporting element satisfy: 1.30 < f2^2 / (π×(D2m^2 - d2m^2)) < 2.95.

[0058] In an exemplary embodiment of the present application, the inner diameter d2m of the inner side surface of the second bearing element, the curvature radius R5 of the outer side surface of the third lens, and the curvature radius R6 of the inner side surface of the third lens satisfy: -4.5 < (R5 + R6) / d2m < -3. By controlling this condition, the curvature radii of the near-light surface and the far-light surface of the second lens are restricted, which is beneficial to reducing the sensitivity of the second lens, thereby improving the assembly yield; secondly, the inner diameter of the near-light surface of the second bearing element can be restricted to ensure its processability. More specifically, the inner diameter d2m of the inner side surface of the second bearing element, the curvature radius R5 of the outer side surface of the third lens, and the curvature radius R6 of the inner side surface of the third lens satisfy: -4.1 < (R5 + R6) / d2m < -3.8.

[0059] In an exemplary embodiment of the present application, the refractive index N2 of the second lens, the maximum thickness CP2 of the second bearing element, and the distance T23 between the second lens and the third lens on the optical axis satisfy: 1 < CP2 / T23 × N2 < 37. By controlling the interval between the second lens and the third lens, it is beneficial to reducing the body height and indirectly controlling the thickness of the second spacer element. Both are beneficial to the miniaturization of the VR lens; by controlling the refractive index of the second lens, the optical power of the second lens can be controlled. Combining with the air interval of the lens, the focal length of the system can be controlled, thereby restricting the system field of view angle to meet the purpose of wide angle of the head-mounted device. More specifically, the refractive index N2 of the second lens, the maximum thickness CP2 of the second bearing element, and the distance T23 between the second lens and the third lens on the optical axis satisfy: 1.5 < CP2 / T23 × N2 < 36.5.

[0060] In an exemplary embodiment of the present application, the dispersion coefficient V1 of the first lens, the effective focal length f1 of the first lens, and the inner diameter d1m of the inner side surface of the first bearing element satisfy: -65 < V1 × f1 / d1m < -62. By controlling the ratio of the effective focal length and Abbe number of the first lens to the inner diameter of the first lens on the near-light source side, it is beneficial to the setting of the optical power and Abbe number of the first lens, and the shape of the first lens can be effectively controlled. It is beneficial to the excess light generated at the edge after the light passes through the first lens and is refracted and reflected to be blocked by the first spacer, obtaining the best image quality. More specifically, the dispersion coefficient V1 of the first lens, the effective focal length f1 of the first lens, and the inner diameter d1m of the inner side surface of the first bearing element satisfy: -64 < V1 × f1 / d1m < -62.5.

[0061] In an exemplary embodiment of the present application, the dispersion coefficient V2 of the second lens, the inner diameter d2s of the outer side surface of the second supporting element, and the effective focal length f2 of the second lens satisfy: 73 < V2 × f2 / d2s < 82. By controlling the focal length and Abbe number of the second lens, on the premise of meeting the system focal length, it is beneficial to correct the chromatic aberration of the system and improve the imaging quality of the system; by controlling the ratio of the effective focal length and Abbe number of the second lens to the inner diameter of the first spacer on the human eye side, it is beneficial to set the optical power and Abbe number of the second lens, and can effectively control the shape of the second lens, which is beneficial to the excess light generated at the edge after the light passes through the first lens and is refracted or reflected to be blocked by the first spacer, and the effective light can obtain the best image quality after being refracted or reflected by the first lens. More specifically, the dispersion coefficient V2 of the second lens, the inner diameter d2s of the outer side surface of the second supporting element, and the effective focal length f2 of the second lens satisfy: 74 < V2 × f2 / d2s < 81.

[0062] In an exemplary embodiment of the present application, the distance EP12 between the first supporting element and the second supporting element in the horizontal direction, the distance EP01 between the lens barrel and the first supporting element in the horizontal direction, and the maximum length L of the lens barrel satisfy: 0.5 < (EP01 + EP12) / L < 0.6. Through the above relational expression, the top surface thickness of the lens barrel and the thickness of the second lens can be controlled to ensure the processability and supporting stability of the supported lens. In addition, L is smaller, making the entire lens group more compact and beneficial to miniaturized design. More specifically, the distance EP12 between the first supporting element and the second supporting element in the horizontal direction, the distance EP01 between the lens barrel and the first supporting element in the horizontal direction, and the maximum length L of the lens barrel satisfy: 0.51 < (EP01 + EP12) / L < 0.55.

[0063] In an exemplary embodiment of the present application, the thickness CT2 of the second lens on the optical axis, the maximum thickness CP2 of the second supporting element, and the maximum thickness CP1 of the first supporting element satisfy: 0.1 < (CP1 + CP2) / CT2 < 0.5. By controlling the above relational expression, the center thickness of the second lens and the thickness of the supporting element are controlled. First, it is beneficial to reduce the overall length of the machine and is beneficial to the miniaturization of the system. Second, it is beneficial to reduce the deformation after the lens and the spacer element are assembled, and makes a certain contribution to the assembly stability. More specifically, the thickness CT2 of the second lens on the optical axis, the maximum thickness CP2 of the second supporting element, and the maximum thickness CP1 of the first supporting element satisfy: 0.15 < (CP1 + CP2) / CT2 < 0.45.

[0064] In an exemplary embodiment of the present application, for the semi-field of view (semi-FOV) which is half of the maximum field of view of the eyepiece imaging system, the maximum length L of the lens barrel, the outer diameter D0m of the inner side surface of the lens barrel, and the outer diameter D0s of the outer side surface of the lens barrel, the following is satisfied: 2.5 < TAN(semi-FOV) × L / (D0m - D0s) < 5.5. Through the above relational expression, the field of view of the system is effectively constrained, so that the system meets the characteristics of a large field of view of a VR lens; at the same time, by constraining the inner and outer diameter dimensions of the image source side of the lens barrel, the step structure in the radial direction of the system is reduced, and the yield rate during the lens assembly process is improved. At the same time, by constraining the outer dimension of the lens barrel, on the premise of ensuring the machinability of the lens barrel, the outer dimension of the lens barrel is made as small as possible, thereby reducing the overall size of the whole machine. More specifically, for the semi-field of view (semi-FOV) which is half of the maximum field of view of the eyepiece imaging system, the maximum length L of the lens barrel, the outer diameter D0m of the inner side surface of the lens barrel, and the outer diameter D0s of the outer side surface of the lens barrel, the following is satisfied: 3.0 < TAN(semi-FOV) × L / (D0m - D0s) < 5.2.

[0065] In an exemplary embodiment of the present application, for the focal length f1 of the first lens, the inner diameter d1m of the inner side surface of the first supporting element, and the outer diameter D1m of the inner side surface of the first supporting element, the following is satisfied: 29 < |f1 / (D1m - d1m)| < 39. Through this condition control, the light trend can be effectively controlled, avoiding the problem of too high sensitivity of the lens caused by overly steep light. By controlling the size range of the inner and outer diameters of the light-incident surface of the first spacer element, the excess light is blocked, which helps to improve the overall stray light of the lens. More specifically, for the focal length f1 of the first lens, the inner diameter d1m of the inner side surface of the first supporting element, and the outer diameter D1m of the inner side surface of the first supporting element, the following is satisfied: 29.5 < |f1 / (D1m - d1m)| < 38.8.

[0066] In an exemplary embodiment of the present application, the first lens and the second lens have opposite dioptric powers. The chromatic aberration of the eyepiece is optimized by controlling the focal length.

[0067] In an exemplary embodiment of the present application, the visible light reflectivity of at least one supporting element is less than 15%.

[0068] In this exemplary embodiment, the outer side surface and the inner side surface of any one of the first lens E1 to the third lens E3 are aspherical surfaces, and the surface shape x of each aspherical lens can be defined by, but not limited to, the following aspherical formula:

[0069]

[0070] Wherein, x is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c=1 / R (i.e., the paraxial curvature c is the reciprocal of the curvature radius R in Table 1); k is the cone coefficient; Ai is the correction coefficient of the i-th order aspheric surface.

[0071] In this exemplary embodiment, the eyepiece imaging system may further include a stop. The stop may be disposed at an appropriate position as required, for example, the stop may be disposed on the object side and outside the first lens away from the light source.

[0072] The eyepiece imaging system according to the above embodiment of the present application can use multiple lenses, such as the above three lenses. By reasonably allocating the focal length, surface shape, center thickness of each lens, and axial spacing between lenses, the eyepiece imaging system has a small size and volume, has the characteristics of a wide imaging range and high imaging quality, and ensures the ultra-thinness of the mobile phone.

[0073] In an exemplary embodiment, at least one of the mirror surfaces of each lens is an aspherical mirror surface, that is, at least one of the mirror surfaces from the outer side surface of the first lens to the inner side surface of the third lens is an aspherical mirror surface. The characteristics of an aspherical lens are: the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens with a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has a better curvature radius characteristic, and has the advantages of improving distortion aberration and improving astigmatism aberration. After adopting an aspherical lens, the aberration that occurs during imaging can be eliminated as much as possible, thereby improving the imaging quality. Optionally, at least one of the outer side surface and the inner side surface of each lens in the first lens, the second lens and the third lens is an aspherical mirror surface. Optionally, the outer side surface and the inner side surface of each lens in the first lens, the second lens and the third lens are all aspherical mirror surfaces.

[0074] However, those skilled in the art should understand that, without departing from the technical solution claimed in the present application, the number of lenses constituting the eyepiece imaging system can be changed to obtain the various results and advantages described in this specification. For example, although three lenses are used as an example in the embodiment, the eyepiece imaging system is not limited to including three lenses, and the eyepiece imaging system may also include other numbers of lenses if necessary.

[0075] The following further describes a specific embodiment of the eyepiece imaging system applicable to the above embodiment with reference to the accompanying drawings. Specific embodiment 1

[0077] Figures 2 to 4The three structural schematic diagrams of the eyepiece imaging system embodiment 1 of the present application, the eyepiece imaging system includes in order from the object side to the image side along the optical axis: an aperture STO, a reflective polarizing element RP, a quarter wave plate QWP, a first lens E1, a second lens E2, a third lens E3 and a light source S9. Among them, the first lens, the second lens and the third lens are arranged in order from the outside to the inside along the optical axis; each of the first lens to the third lens has at least one outer side surface away from the light source and an inner side surface close to the light source. A first supporting element is provided between the first lens E1 and the second lens E2, the first supporting element includes at least one outer side surface away from the light source and an inner side surface close to the light source, the first supporting element is placed between the first lens and the second lens and its outer side surface is closest to the first lens along the optical axis direction compared to the outer side surfaces of other supporting elements. A second supporting element is provided between the second lens E2 and the third lens E3, and the second supporting element includes at least one outer side surface away from the light source and an inner side surface close to the light source. The second supporting element is placed between the second lens and the third lens, and its outer side surface is closest to the second lens along the optical axis direction compared to the outer side surfaces of other supporting elements.

[0078] Among them, the light source emits a circularly polarized light, which passes through the third lens, the second lens, the first lens and the quarter wave plate to become linearly polarized light, is reflected after passing through the reflective polarization element, and then passes through the quarter wave plate, the first lens, the second lens, is reflected by the partial reflective layer on the third lens, and finally passes through the second lens, the first lens, the quarter wave plate, the reflective polarization element, and enters the human eye.

[0079] As shown in Table 1, it is a basic parameter table of the eyepiece imaging system of Example 1, wherein the units of the curvature radius, thickness, and focal length are all millimeters (mm).

[0080]

[0081] Table 1

[0082] As shown in Table 2, in Example 1, the total effective focal length f of the eyepiece imaging system is 30.12 mm, the focal length f1 of the first lens E1 is -216.52 mm, the focal length f2 of the second lens E2 is 88.22 mm, and the focal length f3 of the third lens E3 is 213.41 mm.

[0083]

[0084]

[0085] Table 2

[0086] The three eyepiece imaging systems in Example 1 satisfy:

[0087] f2^2 / (π×(D2m^2-d2m^2))=1.36 / 1.42 / 1.42, wherein f2 is the effective focal length of the second lens, D2m is the outer diameter of the inner side surface of the second supporting element P2, and d2m is the inner diameter of the inner side surface of the second supporting element P2.

[0088] EPD×(D0s+d0s) / (D0s-d0s)=57.00 / 83.58 / 83.58. Wherein, EPD is the entrance pupil diameter of the eyepiece, D0s is the outer diameter of the outer side of the lens barrel P0, and d0s is the inner diameter of the outer side of the lens barrel P0.

[0089] d0m / FL = 9.15 / 9.09 / 9.09, where FL is the back focus of the eyepiece and d0m is the inner diameter of the inner side of the lens barrel P0.

[0090] (R5+R6) / d2m=-4.02 / -4.02 / -4.02, wherein d2m is the inner diameter of the inner side surface of the second supporting element P2, R5 is the curvature radius of the outer side surface of the third lens, and R6 is the curvature radius of the inner side surface of the third lens.

[0091] CP2 / T23×N2=1.54 / 1.54 / 1.54, wherein N2 is the refractive index of the second lens, CP2 is the maximum thickness of the second supporting element P2, and T23 is the distance between the second lens and the third lens on the optical axis.

[0092] V1×f1 / d1m=-62.81 / -62.81 / -62.81, wherein V1 is the dispersion coefficient of the first lens, f1 is the effective focal length of the first lens, and d1m is the inner diameter of the inner side surface of the first supporting element P1.

[0093] V2×f2 / d2s=80.03 / 80.03 / 80.03, wherein V2 is the dispersion coefficient of the second lens, d2s is the inner diameter of the outer side surface of the second supporting element P2, and f2 is the effective focal length of the second lens.

[0094] (EP01+EP12) / L=0.53 / 0.53 / 0.53, wherein EP12 is the distance between the first supporting element P1 and the second supporting element P2 in the horizontal direction, EP01 is the distance between the lens barrel P0 and the first supporting element P1 in the horizontal direction, and L is the maximum length of the lens barrel.

[0095] CP1+CP2 / CT2=0.21 / 0.21 / 0.21, wherein CT2 is the thickness of the second lens on the optical axis, CP2 is the maximum thickness of the second supporting element P2, and CP1 is the maximum thickness of the first supporting element P1.

[0096] TAN (semi-FOV) × L / (D0m-D0s) = 4.78 / 3.04 / 3.04. Among them, semi-FOV is half of the maximum field of view of the eyepiece, L is the maximum length of the lens barrel, D0m is the outer diameter of the inner side of the lens barrel P0, and D0s is the outer diameter of the outer side of the lens barrel P0.

[0097] |f1 / (D1m-d1m)|=29.52 / 31.68 / 31.68, wherein f1 is the focal length of the first lens, d1m is the inner diameter of the inner side surface of the first supporting element P1, and D1m is the outer diameter of the inner side surface of the first supporting element P1.

[0098] In Example 1, the outer side surface and the inner side surface of any one of the first lens E1 to the third lens E3 are aspherical surfaces. Table 3 shows the high-order coefficients A0, A1, A2, and A3 of the aspherical mirror surfaces S4, S5, S6, S7, and S8 that can be used in Example 1.

[0099] Face number A0 A1 A2 A3 S4 -6.6432E-02 1.8077E-01 -2.3484E-02 8.3382E-02 S5 2.6555E-01 2.5411E-02 -1.4336E-01 5.3124E-02 S6 -1.6482E-01 -3.0792E-01 6.8021E-03 -9.2293E-03 S7 1.3559E-01 2.0474E-04 -3.9216E-02 -4.7567E-03 S8 -2.4170E-02 -2.7007E-01 -1.9162E-01 -2.1132E-01

[0100] Table 3

[0101] Figure 5a The axial chromatic aberration curve of the optical system of Example 1 is shown, which indicates the deviation of the focusing point of light of different wavelengths after passing through the lens. Figure 5b An astigmatism curve of the optical system of Example 1 is shown, which indicates meridional field curvature and sagittal field curvature. Figure 5c The distortion curve of the optical system of Example 1 is shown, which represents the distortion magnitude value under different viewing angles. Figure 5d The relative illumination curve of the optical system of Example 1 is shown, which represents the relative illumination corresponding to different field angles on the imaging surface. Figure 5a to Figure 5d It can be seen from the figure that the optical system provided in Example 1 can achieve good imaging quality. Specific embodiment 2

[0103] Figures 6 to 8The three structural schematic diagrams of the embodiment 2 of the eyepiece imaging system of the present application, the eyepiece imaging system includes in order from the object side to the image side along the optical axis: an aperture STO, a reflective polarizing element RP, a quarter wave plate QWP, a first lens E1, a second lens E2, a third lens E3 and a light source S9. Among them, the first lens, the second lens and the third lens are arranged in order from the outside to the inside along the optical axis; each of the first lens to the third lens has at least one outer side surface away from the light source and an inner side surface close to the light source. A first supporting element is provided between the first lens E1 and the second lens E2, the first supporting element includes at least one outer side surface away from the light source and an inner side surface close to the light source, the first supporting element is placed between the first lens and the second lens and its outer side surface is closest to the first lens along the optical axis direction compared to the outer side surfaces of other supporting elements. A second supporting element is provided between the second lens E2 and the third lens E3, and the second supporting element includes at least one outer side surface away from the light source and an inner side surface close to the light source. The second supporting element is placed between the second lens and the third lens, and its outer side surface is closest to the second lens along the optical axis direction compared to the outer side surfaces of other supporting elements.

[0104] Among them, the light source emits a circularly polarized light, which passes through the third lens, the second lens, the first lens and the quarter wave plate to become linearly polarized light, is reflected after passing through the reflective polarization element, and then passes through the quarter wave plate, the first lens, the second lens, is reflected by the partial reflective layer on the third lens, and finally passes through the second lens, the first lens, the quarter wave plate, the reflective polarization element, and enters the human eye.

[0105] As shown in Table 4, it is a basic parameter table of the eyepiece imaging system of Example 2, wherein the units of the radius of curvature, thickness, and focal length are all millimeters (mm).

[0106]

[0107] Table 4

[0108] As shown in Table 5, in Example 2, the total effective focal length of the eyepiece imaging system is f=30.11 mm, the focal length of the first lens E1 is f1=-220.59 mm, the focal length of the second lens E2 is f2=88.83 mm, and the focal length of the third lens E3 is f3=218.17 mm.

[0109]

[0110]

[0111] Table 5

[0112] The three eyepiece imaging systems in Example 2 satisfy:

[0113] f2^2 / (π×(D2m^2-d2m^2))=2.48 / 1.44 / 2.79, wherein f2 is the effective focal length of the second lens, D2m is the outer diameter of the inner side surface of the second supporting element P2, and d2m is the inner diameter of the inner side surface of the second supporting element P2.

[0114] EPD×(D0s+d0s) / (D0s-d0s)=54.56 / 56.60 / 56.60, wherein EPD is the entrance pupil diameter of the eyepiece, D0s is the outer diameter of the outer side of the lens barrel P0, and d0s is the inner diameter of the outer side of the lens barrel P0.

[0115] d0m / FL = 9.00 / 8.94 / 8.94, where FL is the back focus of the eyepiece and d0m is the inner diameter of the inner side of the lens barrel P0.

[0116] (R5+R6) / d2m=-3.82 / -4.05 / -3.88, wherein d2m is the inner diameter of the inner side surface of the second supporting element P2, R5 is the curvature radius of the outer side surface of the third lens, and R6 is the curvature radius of the inner side surface of the third lens.

[0117] CP2 / T23×N2=1.54 / 1.54 / 35.24, wherein N2 is the refractive index of the second lens, CP2 is the maximum thickness of the second supporting element P2, and T23 is the distance between the second lens and the third lens on the optical axis.

[0118] V1×f1 / d1m=-63.99 / -63.99 / -63.99, wherein V1 is the dispersion coefficient of the first lens, f1 is the effective focal length of the first lens, and d1m is the inner diameter of the inner side surface of the first supporting element P1.

[0119] V2×f2 / d2s=80.59 / 80.59 / 74.68, wherein V2 is the dispersion coefficient of the second lens, d2s is the inner diameter of the outer side surface of the second supporting element P2, and f2 is the effective focal length of the second lens.

[0120] (EP01+EP12) / L=0.52 / 0.52 / 0.53. EP12 is the distance between the first supporting element P1 and the second supporting element P2 in the horizontal direction, EP01 is the distance between the lens barrel P0 and the first supporting element P1 in the horizontal direction, and L is the maximum length of the lens barrel.

[0121] (CP1+CP2) / CT2=0.21 / 0.21 / 0.43, wherein CT2 is the thickness of the second lens on the optical axis, CP2 is the maximum thickness of the second supporting element P2, and CP1 is the maximum thickness of the first supporting element P1.

[0122] TAN (semi-FOV) × L / (D0m-D0s) = 5.02 / 5.02 / 4.94. Among them, semi-FOV is half of the maximum field of view of the eyepiece, L is the maximum length of the lens barrel, D0m is the outer diameter of the inner side of the lens barrel P0, and D0s is the outer diameter of the outer side of the lens barrel P0.

[0123] |f1 / (D1m-d1m)|=30.08 / 32.28 / 32.28, wherein f1 is the focal length of the first lens, d1m is the inner diameter of the inner side surface of the first supporting element P1, and D1m is the outer diameter of the inner side surface of the first supporting element P1.

[0124] In Example 2, the outer side surface and the inner side surface of any one of the first lens E1 to the third lens E3 are aspherical surfaces. Table 6 shows the high-order coefficients A0, A1, A2, and A3 of the aspherical mirror surfaces S4, S5, S6, S7, and S8 that can be used in Example 2.

[0125]

[0126]

[0127] Table 6

[0128] Figure 9a The axial chromatic aberration curve of the optical system of Example 2 is shown, which indicates that light of different wavelengths deviates from the focal point behind the lens. Figure 9b An astigmatism curve of the optical system of Example 2 is shown, which indicates meridional field curvature and sagittal field curvature. Fig.9c The distortion curve of the optical system of Example 2 is shown, which represents the distortion magnitude value under different viewing angles. Figure 9d The relative illumination curve of the optical system of Example 2 is shown, which represents the relative illumination corresponding to different field angles on the imaging surface. Figures 9a to 9d It can be seen from the figure that the optical system provided in Example 2 can achieve good imaging quality. Specific embodiment 3

[0130] Figures 10 to 12The three structural schematic diagrams of the eyepiece imaging system embodiment 3 of the present application, the eyepiece imaging system includes, in order from the object side to the image side along the optical axis: an aperture STO, a reflective polarizing element RP, a quarter wave plate QWP, a first lens E1, a second lens E2, a third lens E3 and a light source S9. Among them, the first lens, the second lens and the third lens are arranged in sequence from the outside to the inside along the optical axis; each of the first lens to the third lens has at least one outer side surface away from the light source and an inner side surface close to the light source. A first supporting element is provided between the first lens E1 and the second lens E2, the first supporting element includes at least one outer side surface away from the light source and an inner side surface close to the light source, the first supporting element is placed between the first lens and the second lens and its outer side surface is closest to the first lens along the optical axis direction compared to the outer side surfaces of other supporting elements. A second supporting element is provided between the second lens E2 and the third lens E3, and the second supporting element includes at least one outer side surface away from the light source and an inner side surface close to the light source. The second supporting element is placed between the second lens and the third lens, and its outer side surface is closest to the second lens along the optical axis direction compared to the outer side surfaces of other supporting elements.

[0131] Among them, the light source emits a circularly polarized light, which passes through the third lens, the second lens, the first lens and the quarter wave plate to become linearly polarized light, is reflected after passing through the reflective polarization element, and then passes through the quarter wave plate, the first lens, the second lens, is reflected by the partial reflective layer on the third lens, and finally passes through the second lens, the first lens, the quarter wave plate, the reflective polarization element, and enters the human eye.

[0132] As shown in Table 7, it is a basic parameter table of the eyepiece imaging system of Example 3, wherein the units of the curvature radius, thickness, and focal length are all millimeters (mm).

[0133]

[0134]

[0135] Table 7

[0136] As shown in Table 8, in Example 3, the total effective focal length of the eyepiece imaging system is f=30.12 mm, the focal length of the first lens E1 is f1=-218.40 mm, the focal length of the second lens E2 is f2=88.34 mm, and the focal length of the third lens E3 is f3=217.23 mm.

[0137]

[0138] Table 9

[0139] The three eyepiece imaging systems in Example 3 satisfy:

[0140] f2^2 / (π×(D2m^2-d2m^2))=1.37 / 1.49 / 2.94, wherein f2 is the effective focal length of the second lens, D2m is the outer diameter of the inner side surface of the second supporting element P2, and d2m is the inner diameter of the inner side surface of the second supporting element P2.

[0141] EPD×(D0s+d0s) / (D0s-d0s)=54.56 / 58.83 / 75.17, wherein EPD is the entrance pupil diameter of the eyepiece, D0s is the outer diameter of the outer side of the lens barrel P0, and d0s is the inner diameter of the outer side of the lens barrel P0.

[0142] d0m / FL = 9.18 / 9.06 / 9.06, where FL is the back focus of the eyepiece and d0m is the inner diameter of the inner side of the lens barrel P0.

[0143] (R5+R6) / d2m=-4.06 / -4.06 / -3.86, wherein d2m is the inner diameter of the inner side surface of the second supporting element P2, R5 is the curvature radius of the outer side surface of the third lens, and R6 is the curvature radius of the inner side surface of the third lens.

[0144] CP2 / T23×N2=1.54 / 1.54 / 36.34, wherein N2 is the refractive index of the second lens, CP2 is the maximum thickness of the second supporting element P2, and T23 is the distance between the second lens and the third lens on the optical axis.

[0145] V1×f1 / d1m=-63.05 / -63.05 / -63.05, wherein V1 is the dispersion coefficient of the first lens, f1 is the effective focal length of the first lens, and d1m is the inner diameter of the inner side surface of the first supporting element P1.

[0146] V2×f2 / d2s=80.15 / 80.15 / 74.20, wherein V2 is the dispersion coefficient of the second lens, d2s is the inner diameter of the outer side surface of the second supporting element P2, and f2 is the effective focal length of the second lens.

[0147] (EP01+EP12) / L=0.53 / 0.53 / 0.54. EP12 is the distance between the first supporting element P1 and the second supporting element P2 in the horizontal direction, EP01 is the distance between the lens barrel P0 and the first supporting element P1 in the horizontal direction, and L is the maximum length of the lens barrel.

[0148] (CP1+CP2) / CT2=0.20 / 0.20 / 0.43, wherein CT2 is the thickness of the second lens on the optical axis, CP2 is the maximum thickness of the second supporting element P2, and CP1 is the maximum thickness of the first supporting element P1.

[0149] TAN (semi-FOV) × L / (D0m-D0s) = 5.02 / 5.02 / 5.15. Among them, semi-FOV is half of the maximum field of view of the eyepiece, L is the maximum length of the lens barrel, D0m is the outer diameter of the inner side of the lens barrel P0, and D0s is the outer diameter of the outer side of the lens barrel P0.

[0150] |f1 / (D1m-d1m)|=32.55 / 38.25 / 38.25, wherein f1 is the focal length of the first lens, d1m is the inner diameter of the inner side surface of the first supporting element P1, and D1m is the outer diameter of the inner side surface of the first supporting element P1.

[0151] In Example 3, the outer side surface and the inner side surface of any one of the first lens E1 to the third lens E3 are aspherical surfaces. Table 9 shows the high-order coefficients A0, A1, A2, and A3 of the aspherical mirror surfaces S4, S5, S6, S7, and S8 that can be used in Example 3.

[0152] Face number A0 A1 A2 A3 S4 -6.6527E-02 1.8159E-01 -2.4477E-02 8.0683E-02 S5 2.6579E-01 2.6581E-02 -1.4476E-01 4.9900E-02 S6 -1.6607E-01 -3.0752E-01 5.8513E-03 -9.0554E-03 S7 1.3990E-01 -1.1824E-03 -3.8568E-02 -4.6415E-03 S8 -2.9602E-02 -2.6835E-01 -1.9086E-01 -2.1205E-01

[0153] Table 9

[0154] Fig.13a The axial chromatic aberration curve of the optical system of Example 3 is shown, which indicates that light of different wavelengths deviates from the focal point behind the lens. Fig.13b An astigmatism curve of the optical system of Example 3 is shown, which indicates meridional field curvature and sagittal field curvature. Fig.13c The distortion curve of the optical system of Example 3 is shown, which represents the distortion magnitude value under different viewing angles. Fig.13d The relative illumination curve of the optical system of Example 3 is shown, which represents the relative illumination corresponding to different field angles on the imaging surface. Figures 13a to 13d It can be seen from the figure that the optical system provided in Example 3 can achieve good imaging quality.

[0155] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, improvements, equivalent substitutions, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An eyepiece imaging system, characterized in that: The eyepiece imaging system comprises: a lens barrel, a first lens group, a second lens group, a third lens group, a plurality of supporting elements and a light source; The first lens group includes a first lens; The second lens group includes a second lens; The third lens group includes a third lens; The first lens, the second lens and the third lens are arranged in sequence from the outside to the inside along the optical axis; each of the first lens to the third lens has at least one outer side surface away from the light source and one inner side surface close to the light source; The plurality of supporting elements include a first supporting element and a second supporting element; The first supporting element comprises at least one outer side surface away from the light source and an inner side surface close to the light source, the first supporting element is placed between the first lens and the second lens, and its outer side surface is closest to the first lens along the optical axis direction compared to the outer side surfaces of other supporting elements; The second supporting element comprises at least one outer side surface away from the light source and an inner side surface close to the light source, the second supporting element is placed between the second lens and the third lens, and its outer side surface is closest to the second lens along the optical axis direction compared to the outer side surfaces of other supporting elements; Wherein, the back focus FL of the eyepiece imaging system and the inner diameter d0m of the inner side of the lens barrel satisfy: 8.5 <d0m / FL<9.5。 2. The eyepiece imaging system according to claim 1, characterized in that: The eyepiece imaging system also includes a reflective polarizing element and a quarter-wave plate; The reflective polarizing element and the quarter wave plate are located in the first lens group, and the reflective polarizing element and the quarter wave plate are attached to the outer side surface of the first lens; The outer side surface of the third lens has a partial reflection layer.

3. The eyepiece imaging system according to claim 1, characterized in that: The entrance pupil diameter EPD of the eyepiece imaging system, the outer diameter D0s of the outer side of the lens barrel, and the inner diameter d0s of the outer side of the lens barrel satisfy: 50mm <EPD×(D0s+d0s) / (D0s-d0s)<85mm。 4. The eyepiece imaging system according to claim 1, characterized in that: The effective focal length f2 of the second lens, the outer diameter D2m of the inner side surface of the second supporting element and the inner diameter d2m of the inner side surface of the second supporting element satisfy: 1 <f2^2 / (π×(D2m^2-d2m^2))<3。 5. The eyepiece imaging system according to claim 1, characterized in that: The inner diameter d2m of the inner side surface of the second supporting element, the curvature radius R5 of the outer side surface of the third lens, and the curvature radius R6 of the inner side surface of the third lens satisfy: -4.5<(R5+R6) / d2m<-3.

6. The eyepiece imaging system according to claim 1, characterized in that: The refractive index N2 of the second lens, the maximum thickness CP2 of the second supporting element, and the distance T23 between the second lens and the third lens on the optical axis satisfy: 1 <CP2 / T23×N2<37。 7. The eyepiece imaging system according to claim 1, characterized in that: The dispersion coefficient V1 of the first lens, the effective focal length f1 of the first lens, and the inner diameter d1m of the inner side of the first supporting element satisfy: -65 <V1×f1 / d1m<-62。 8. The eyepiece imaging system according to claim 1, characterized in that: The dispersion coefficient V2 of the second lens, the inner diameter d2s of the outer side surface of the second supporting element, and the effective focal length f2 of the second lens satisfy: 73 <V2×f2 / d2s<82。 9. The eyepiece imaging system according to claim 1, characterized in that: A distance EP12 between the first supporting element and the second supporting element in the horizontal direction, a distance EP01 between the lens barrel and the first supporting element in the horizontal direction, and a maximum length L of the lens barrel satisfy: 0.5<(EP01+EP12) / L<0.

6.

10. The eyepiece imaging system according to claim 1, characterized in that: The thickness CT2 of the second lens on the optical axis is equal to the maximum thickness CP2 of the second supporting element, and the maximum thickness CP1 of the first supporting element satisfies: 0.1 <CP1+CP2 / CT2<0.5。

Images