Optical system

Abstract

The invention discloses an optical system. The optical system comprises a reflective polarizing element, a quarter-wave plate, a first lens, a second lens, a third lens and a display, the first lens to the third lens are sequentially arranged from the outer side to the inner side along the optical axis. The reflective polarizing element and the quarter-wave plate are arranged on the outer side of the first lens; each of the first to third lenses has at least one outer side surface away from the display and one inner side surface close to the display; the outer side surface or the inner side surface of at least one lens among the first to third lenses is provided with a partial reflection layer; wherein the curvature radius R5 of the outer side surface of the third lens and the curvature radius R4 of the inner side surface of the second lens satisfy 0 lt; r4 / R5. By controlling the ratio of the outer side curvature radius of the third lens to the inner side curvature radius of the second lens, on one hand, the height of light can be effectively controlled, and therefore the display size is reduced; on the other hand, the focal power of the system is reasonably distributed, and the aberration of the system can be improved.

Description

Technical Field

[0001] The present invention relates to the field of optics, and in particular to an optical system. Background Art

[0002] The VR system with folded optical path solution is the main development direction of VR lens. The optical path refraction shortens the length of the equipment and makes the visual optical device thinner and lighter. At present, the imaging of the folded optical path solution system with a single lens in the edge field is poor, which is easy to cause dizziness and greatly reduces the consumer experience. This patent adopts a three-piece folded optical path solution to reduce the thickness of the VR system.

[0003] The preceding description is intended to provide general background information and does not necessarily constitute prior art. Summary of the invention

[0004] The present application aims to provide an optical 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.

[0005] The present application provides an optical system, comprising: a reflective polarizing element, a quarter wave plate, a first lens, a second lens, a third lens, and a display; the first lens to the third lens are arranged in sequence from the outer side to the inner side along the optical axis; the reflective polarizing element and the quarter wave plate are placed on the outer side of the first lens; each of the first lens to the third lens has at least one outer side surface away from the display and one inner side surface close to the display; the outer side surface or the inner side surface of at least one of the first lens to the third lens has a partial reflection layer; wherein the curvature radius R5 of the outer side surface of the third lens and the curvature radius R4 of the inner side surface of the second lens satisfy: 0 <R4 / R5。

[0006] The present application provides an optical system, comprising: a reflective polarizing element, a quarter wave plate, a first lens, a second lens, a third lens, and a display; the first lens to the third lens are arranged in sequence from the outer side to the inner side along the optical axis; the reflective polarizing element and the quarter wave plate are placed outside the first lens; each of the first to third lenses has at least one outer side away from the display and one inner side close to the display; the outer side or the inner side of at least one lens has a partial reflective layer; wherein the effective focal length f of the imaging system and the combined focal length f23 of the second lens and the third lens satisfy: 1 <f23 / f<23。

[0007] According to one embodiment of the present application, the half of the maximum field of view angle of the optical system, semi-fov, and the axial distance TD from the outer side surface of the first lens to the inner side surface of the third lens satisfy: 12 <TD / tan(semi-fov)<18。

[0008] According to one embodiment of the present application, the back focus BL of the optical system and the axial distance TD from the outer side of the first lens to the inner side of the third lens satisfy: 1.6 <TD / BL<3。

[0009] According to one embodiment of the present application, the dispersion coefficient VRP of the reflective polarizing element, the dispersion coefficient V1 of the first lens, and the dispersion coefficient V2 of the second lens satisfy: 0 <VRP / (V1+V2)<1。

[0010] According to one embodiment of the present application, the partial reflective layer of the third lens is plated on the outer side surface or the inner side surface of the third lens.

[0011] According to one embodiment of the present application, the dispersion coefficient VQWP of the quarter wave plate, the dispersion coefficient V3 of the third lens, and the dispersion coefficient V2 of the second lens satisfy: 0.5 <VQWP / (V2+V3)<2。

[0012] According to one embodiment of the present application, the effective focal length f2 of the second lens and the effective focal length f of the optical system satisfy: 1<|f2 / f|<18.

[0013] According to one embodiment of the present application, the effective focal length f of the optical system, the effective focal length f1 of the first lens, and the effective focal length f3 of the third lens satisfy: -0.2 <f / f3-f / f1<0.4。

[0014] According to one embodiment of the present application, a radius of curvature R5 of an outer side surface of the third lens, and a center thickness CT3 of the third lens on the optical axis satisfy: 18<|R5 / CT3|<40.

[0015] According to one embodiment of the present application, the center thickness CT1 of the first lens on the optical axis and the refractive index N1 of the first lens satisfy: 0 <CT1 / CT2 / N1<5。

[0016] According to one embodiment of the present application, the on-axis distance TTL from the outer side of the first lens to the display, the center thickness CT1 of the first lens on the optical axis, the center thickness CT2 of the second lens on the optical axis, and the center thickness CT3 of the third lens on the optical axis satisfy: 0.6<(CT1+CT2+CT3) / TTL<0.8.

[0017] According to one embodiment of the present application, the radius of curvature of the inner surface of the third lens is less than zero.

[0018] Beneficial effects of this application:

[0019] The optical system provided by the present application includes multiple lenses, such as the first lens to the third lens. By controlling the ratio of the outer curvature radius of the third lens to the inner curvature radius of the second lens, on the one hand, the height of the light can be effectively controlled, thereby reducing the size of the display; on the other hand, the optical power of the system is reasonably distributed, which is conducive to improving the aberration of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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.

[0021] Figure 1 This is a schematic diagram of the structure of the optical system of this application;

[0022] Figure 2 A schematic diagram of a partially enlarged structure of the optical system of the present application;

[0023] Figure 3 This is a schematic diagram of the structure of the optical system of this application;

[0024] Figures 4a to 4d They are respectively the axial chromatic aberration curve, the astigmatism curve, the distortion curve and the relative illumination curve of the optical system embodiment 1 of the present application;

[0025] Figure 5 This is a schematic diagram of the structure of the optical system of this application;

[0026] Figures 6a to 6d They are respectively the axial chromatic aberration curve, the astigmatism curve, the distortion curve and the relative illumination curve of the optical system embodiment 2 of the present application;

[0027] Figure 7 This is a schematic diagram of the structure of the optical system of this application;

[0028] Figures 8a to 8d They are respectively the axial chromatic aberration curve, the astigmatism curve, the distortion curve and the relative illumination curve of the optical system embodiment 3 of the present application;

[0029] Fig. 9 This is a schematic diagram of the structure of the optical system of this application;

[0030] Figures 10a to 10dThey are respectively the axial chromatic aberration curve, the astigmatism curve, the distortion curve and the relative illumination curve of the optical system embodiment 4 of the present application;

[0031] Fig.11 This is a schematic diagram of the structure of the optical system of this application;

[0032] Figures 12a to 12d They are respectively the axial chromatic aberration curve, the astigmatism curve, the distortion curve and the relative illumination curve of the optical system embodiment 5 of the present application;

[0033] Fig.13 This is a schematic diagram of the structure of the optical system of this application;

[0034] Figures 14a to 14d They are respectively the axial chromatic aberration curve, the astigmatism curve, the distortion curve and the relative illumination curve of the optical system embodiment 6 of the present application;

[0035] Fig.15 This is a schematic diagram of the structure of the optical system of this application;

[0036] Figures 16a to 16d They are respectively the axial chromatic aberration curve, the astigmatism curve, the distortion curve and the relative illumination curve of the optical system embodiment 7 of the present application;

[0037] Fig.17 This is a schematic diagram of the structure of the optical system of this application;

[0038] Figures 18a to 18d They are respectively the axial chromatic aberration curve, the astigmatism curve, the distortion curve and the relative illumination curve of the optical system embodiment 8 of the present application;

[0039] Fig.19 This is a schematic diagram of the structure of the optical system of this application;

[0040] Figures 20a to 20d They are respectively the axial chromatic aberration curve, astigmatism curve, distortion curve and relative illumination curve of the optical system embodiment 9 of the present application. DETAILED DESCRIPTION

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] In the description of this 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 is called the object side of the lens, and the surface of each lens closest to the imaging surface is called the image side of the lens.

[0046] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal way unless explicitly defined in this article.

[0047] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application 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 accompanying drawings and in combination with the embodiments.

[0048] Exemplary Embodiments

[0049] refer to Figure 1 and Figure 2 As shown, the exemplary optical system of the present application includes: a reflective polarizing element, a quarter-wave plate, a first lens, a second lens, a third lens, and a display; wherein, the first lens to the third lens are arranged in sequence along the optical axis from the outside to the inside; the reflective polarizing element and the quarter-wave plate are placed outside the first lens; wherein, each of the first lens to the third lens has at least one outer side facing away from the display and one inner side facing the display, and wherein, at least one of the outer sides or inner sides of the first lens to the third lens has a partial reflection layer. In an embodiment of the present application, the reflective polarizing element can reflect light of a certain polarization direction and can transmit polarized light perpendicular to the reflected polarized light; the quarter-wave plate can convert linearly polarized light and circularly polarized light to each other, thereby changing the state of the polarized light; the partial reflection element can reflect and transmit; the aspherical surface of the side of the first lens close to the display can be laminated, and the optical path reflection can be achieved.

[0050] In an exemplary embodiment of the present application, the radius of curvature R5 of the outer side of the third lens and the radius of curvature R4 of the inner side of the second lens satisfy: 0 < R4 / R5. By controlling the ratio of the outer curvature radius of the third lens and the inner curvature radius of the second lens, on the one hand, the height of the light can be effectively controlled, thereby reducing the size of the display; on the other hand, the optical power of the system is reasonably distributed, which is beneficial to improving the aberration of the system. More specifically, the radius of curvature R5 of the outer side of the third lens and the radius of curvature R4 of the inner side of the second lens satisfy: 0.01 < R4 / R5.

[0051] In an exemplary embodiment of the present application, the effective focal length f of the imaging system and the combined focal length f23 of the second lens and the third lens satisfy: 1 < f23 / f < 23. In an embodiment of the present application, by controlling the effective focal length of the system and the combined focal length of the second lens and the third lens, the optical power of the system can be made reasonable, thereby improving the imaging quality of the system. More specifically, the effective focal length f of the imaging system and the combined focal length f23 of the second lens and the third lens satisfy: 1.01 < f23 / f < 22.99.

[0052] In an exemplary embodiment of the present application, the half of the maximum field of view angle of the optical system, semi-fov, and the on-axis distance TD from the outer side surface of the first lens to the inner side surface of the third lens satisfy: 12 < TD / tan(semi-fov) < 18. By controlling the ratio of the total length of the lens to the tangent of the maximum half field of view angle, the length of the entire optical system is shortened, the VR system is miniaturized, the weight of the VR product is reduced, and at the same time, the field of view angle of the system can be increased. More specifically, the half of the maximum field of view angle of the optical system, semi-fov, and the on-axis distance TD from the outer side surface of the first lens to the inner side surface of the third lens satisfy: 12.01 < TD / tan(semi-fov) < 17.99.

[0053] In an exemplary embodiment of the present application, the back focal length BL of the optical system and the on-axis distance TD from the outer side surface of the first lens to the inner side surface of the third lens satisfy: 1.6 < TD / BL < 3. In the embodiment of the present application, by controlling the on-axis distance from the outer side surface of the first lens to the inner side surface of the third lens and the back focal length of the imaging system, the system is made more compact, and at the same time, the light can be converged to improve the imaging quality. More specifically, the back focal length BL of the optical system and the on-axis distance TD from the outer side surface of the first lens to the inner side surface of the third lens satisfy: 1.61 < TD / BL < 2.99.

[0054] In an exemplary embodiment of the present application, the dispersion coefficient VRP of the reflective polarizing element, the dispersion coefficient V1 of the first lens, and the dispersion coefficient V2 of the second lens satisfy: 0 < VRP / (V1 + V2) < 1. In the embodiment of the present application, by controlling the dispersion coefficients of the first and second lenses, it is beneficial to select more conventional and more reasonable optical materials, and at the same time, the chromatic aberration of the system can be reduced. More specifically, the dispersion coefficient VRP of the reflective polarizing element, the dispersion coefficient V1 of the first lens, and the dispersion coefficient V2 of the second lens satisfy: 0.01 < VRP / (V1 + V2) < 0.99.

[0055] In an exemplary embodiment of the present application, a partial reflective layer of the third lens is plated on the outer side surface or the inner side surface of the third lens. By plating a reflective layer on the outer side surface or the inner side surface of the third lens and utilizing the reflection and transmission properties of the reflective layer, a folded optical path can be realized, and at the same time, the reflective layer can be prevented from being frequently rubbed during use, thereby damaging the reflective layer.

[0056] In an exemplary embodiment of the present application, the dispersion coefficient VQWP of the quarter-wave plate, the dispersion coefficient V3 of the third lens, and the dispersion coefficient V2 of the second lens satisfy: 0.5 < VQWP / (V2 + V3) < 2. By controlling the ratio of the dispersion coefficient of the quarter-wave plate to the dispersion coefficients of the second lens and the third lens, the chromatic aberration introduced by the quarter-wave plate is reduced, which is beneficial to correcting the chromatic aberration of the system, improving the imaging quality, and enhancing the user experience. More specifically, the dispersion coefficient VQWP of the quarter-wave plate, the dispersion coefficient V3 of the third lens, and the dispersion coefficient V2 of the second lens satisfy: 0.51 < VQWP / (V2 + V3) < 1.99.

[0057] In an exemplary embodiment of the present application, the effective focal length f2 of the second lens and the effective focal length f of the optical system satisfy: 1 < |f2 / f| < 18. By controlling the ratio of the effective focal length of the second lens to the effective focal length of the imaging system, not only the optical power is reasonably distributed, but also the light rays can be converged, improving the performance of the system. More specifically, the effective focal length f2 of the second lens and the effective focal length f of the optical system satisfy: 1.01 < |f2 / f| < 17.99.

[0058] In an exemplary embodiment of the present application, the effective focal length f of the optical system, the effective focal length f1 of the first lens, and the effective focal length f3 of the third lens satisfy: -0.2 < f / f3 - f / f1 < 0.4. By controlling the effective focal length of the system and the effective focal lengths of the first lens and the third lens, the optical power can be reasonably distributed, and at the same time, the effective focal length can be reduced to shorten the optical system. Combining with coating a reflective layer on the lens and the quarter-wave plate, the light path can be folded and reversed, making the visual optical device thinner and lighter. More specifically, the effective focal length f of the optical system, the effective focal length f1 of the first lens, and the effective focal length f3 of the third lens satisfy: -0.21 < f / f3 - f / f1 < 0.39.

[0059] In an exemplary embodiment of the present application, the curvature radius R5 of the outer side surface of the third lens and the central thickness CT3 of the third lens on the optical axis satisfy: 18 < |R5 / CT3| < 40. By controlling the ratio of the curvature radius of the outer side surface of the third lens to the central thickness of the lens, the optical path is effectively shortened, making the system more compact. At the same time, the bending degree of the lens is effectively controlled, expanding the field of view angle; in addition, it is also beneficial to the shaping of the third lens. More specifically, the curvature radius R5 of the outer side surface of the third lens and the central thickness CT3 of the third lens on the optical axis satisfy: 18.01 < |R5 / CT3| < 39.99.

[0060] In an exemplary embodiment of the present application, the central thickness CT1 of the first lens on the optical axis and the refractive index N1 of the first lens satisfy: 0 < CT1 / CT2 / N1 < 5. By controlling the central thicknesses of the first lens and the second lens and the refractive index of the first lens, on the one hand, it is beneficial to reduce the processability of lens forming, and on the other hand, it helps to select reasonable and low-stress optical materials to avoid affecting the polarization state of the system, thereby improving the performance of the system. More specifically, the central thickness CT1 of the first lens on the optical axis and the refractive index N1 of the first lens satisfy: 0.01 < CT1 / CT2 / N1 < 4.99.

[0061] In an exemplary embodiment of the present application, the on-axis distance TTL from the outer side surface of the first lens to the display, the central thickness CT1 of the first lens on the optical axis, the central thickness CT2 of the second lens on the optical axis, and the central thickness CT3 of the third lens on the optical axis satisfy: 0.6 < (CT1 + CT2 + CT3) / TTL < 0.8. By controlling the total length of the optical system and the central thicknesses of the first lens, the second lens, and the third lens, not only can the thickness of the lens be limited, but also the length of the optical system can be shortened, making the VR product lighter and more comfortable to wear. More specifically, the on-axis distance TTL from the outer side surface of the first lens to the display, the central thickness CT1 of the first lens on the optical axis, the central thickness CT2 of the second lens on the optical axis, and the central thickness CT3 of the third lens on the optical axis satisfy: 0.61 < (CT1 + CT2 + CT3) / TTL < 0.79.

[0062] In an exemplary embodiment of the present application, the radius of curvature R6 of the inner side surface of the third lens satisfies: R6 < 0. By controlling the radius of curvature of the inner side surface of the third lens, the bending degree of the third lens can be effectively limited, thereby focusing the light path and increasing the imaging effect. On the other hand, it is possible to reduce the ghost image of the Display and the side surface of the display. More specifically, the radius of curvature R6 of the inner side surface of the third lens satisfies: R6 < -0.01.

[0063] 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:

[0064]

[0065] where x is the sagitta of the distance from the vertex of the aspherical surface when the aspherical surface is along the optical axis at a position with a height of h; c is the paraxial curvature of the aspherical surface, c = 1 / R (that is, the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1); k is the conic coefficient; and Ai is the correction coefficient of the i-th order of the aspherical surface.

[0066] In this exemplary embodiment, the optical system may further include a stop. The stop may be disposed at an appropriate position as required, for example, the stop may be disposed between the object side and the first lens. Optionally, the optical system may further include a filter for correcting color deviation and / or a protective glass for protecting a photosensitive element located on the imaging surface.

[0067] The optical system according to the above embodiment of the present application may 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 optical system has a smaller size and volume, has the characteristics of a wide imaging range and high imaging quality, and ensures the ultra-thinness of the mobile phone.

[0068] 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.

[0069] 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 optical 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 optical system is not limited to including three lenses, and the optical system may also include other numbers of lenses if necessary.

[0070] Specific embodiments of the optical system applicable to the above-mentioned embodiments will be further described below with reference to the accompanying drawings. Specific embodiment 1

[0072] Figure 3 This is a schematic diagram of the structure of the optical system embodiment 1 of the present application. The optical system includes, 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 an imaging surface S9. Each of the first to third lenses has at least one outer side surface away from the display and one inner side surface close to the display; at least one of the first to third lenses has a partial reflective layer on its outer side surface or inner side surface.

[0073] Among them, the display emits a circularly polarized light (a quarter wave plate is attached in front of the display), which passes through the third lens, the second lens, the first lens and the quarter wave plate, becomes linearly polarized light, passes through the reflective polarization element and then reflects, 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.

[0074] As shown in Table 1, it is a basic parameter table of the optical system of Example 1, wherein the units of the radius of curvature, thickness, and focal length are all millimeters (mm).

[0075]

[0076] Table 1

[0077] As shown in Table 2, in Example 1, the total effective focal length of the optical system is f=30.12 mm, the back focus of the optical system is BL=8.47 mm, and half of the maximum field of view of the optical system, semi-fov=53.0°.

[0078]

[0079] Table 2

[0080] The optical imaging lens in Example 1 satisfies:

[0081] R4 / R5=0.57, where R5 is the radius of curvature of the outer side surface of the third lens, and R4 is the radius of curvature of the inner side surface of the second lens.

[0082] f23 / f=2.13, wherein f is the effective focal length of the optical system, and f23 is the combined focal length of the second lens and the third lens.

[0083] TD / tan(semi-fov)=16.05, wherein semi-fov is half of the maximum field of view of the optical system, and TD is the axial distance from the outer side surface of the first lens to the inner side surface of the third lens.

[0084] TD / BL=2.52, where BL is the back focus of the optical system, and TD is the axial distance from the outer side surface of the first lens to the inner side surface of the third lens.

[0085] VRP / (V1+V2)=0.76, wherein VRP is the dispersion coefficient of the reflective polarizing element, V1 is the dispersion coefficient of the first lens, and V2 is the dispersion coefficient of the second lens.

[0086] VQWP / (V2+V3)=0.76, wherein VQWP is the dispersion coefficient of the quarter wave plate, V3 is the dispersion coefficient of the third lens, and V2 is the dispersion coefficient of the second lens.

[0087] |f2 / f|=2.93, where f2 is the effective focal length of the second lens, and f is the effective focal length of the optical system.

[0088] f / f3-f / f1=0.28, wherein f is the effective focal length of the optical system, f1 is the effective focal length of the first lens, and f3 is the effective focal length of the third lens.

[0089] |R5 / CT3|=27.70, wherein R5 is the radius of curvature of the outer side surface of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

[0090] CT1 / CT2 / N1=0.38, wherein CT1 is the center thickness of the first lens on the optical axis, and N1 is the refractive index of the first lens.

[0091] (CT1+CT2+CT3) / TTL=0.71, wherein TTL is the on-axis distance from the outer side of the first lens to the display, CT1 is the center thickness of the first lens on the optical axis, CT2 is the center thickness of the second lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

[0092] 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 A4, A6, A8, and A10 of the aspherical mirror surfaces S4, S5, S6, S7, and S8 that can be used in Example 1.

[0093] Face number A4 A6 A8 A10 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

[0094] Table 3

[0095] Figure 4a The axial chromatic aberration curve of the optical system of Example 1 is shown, which indicates the deviation of light of different wavelengths from the focal point behind the lens. Figure 4b An astigmatism curve of the optical system of Example 1 is shown, which indicates meridional field curvature and sagittal field curvature. Figure 4c The distortion curve of the optical system of Example 1 is shown, which represents the distortion magnitude value under different viewing angles. Figure 4d 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. Figures 4a to 4d It can be seen from the figure that the optical system provided in Example 1 can achieve good imaging quality. Specific embodiment 2

[0097] Figure 5 This is a schematic diagram of the structure of the optical system embodiment 2 of the present application. The optical system includes, 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 an imaging surface S9. Each of the first to third lenses has at least one outer side surface away from the display and one inner side surface close to the display; at least one of the first to third lenses has a partial reflective layer on its outer side surface or inner side surface.

[0098] Among them, the display emits a circularly polarized light (a quarter wave plate is attached in front of the display), which passes through the third lens, the second lens, the first lens and the quarter wave plate, becomes linearly polarized light, passes through the reflective polarization element and then reflects, 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.

[0099] As shown in Table 4, it is a basic parameter table of the optical system of Example 2, wherein the units of the radius of curvature, thickness, and focal length are all millimeters (mm).

[0100]

[0101]

[0102] Table 4

[0103] As shown in Table 5, in Example 2, the total effective focal length of the optical system is f=30.11 mm, the back focus of the optical system is BL=8.61 mm, and half of the maximum field of view of the optical system, semi-fov=53.0°.

[0104]

[0105] Table 5

[0106] The optical imaging lens in Example 2 satisfies:

[0107] R4 / R5=0.57, where R5 is the radius of curvature of the outer side surface of the third lens, and R4 is the radius of curvature of the inner side surface of the second lens.

[0108] f23 / f=2.15, wherein f is the effective focal length of the optical system, and f23 is the combined focal length of the second lens and the third lens.

[0109] TD / tan(semi-fov)=15.96, wherein semi-fov is half of the maximum field of view of the optical system, and TD is the axial distance from the outer side surface of the first lens to the inner side surface of the third lens.

[0110] TD / BL=2.46, where BL is the back focus of the optical system, and TD is the axial distance from the outer side surface of the first lens to the inner side surface of the third lens.

[0111] VRP / (V1+V2)=0.76, wherein VRP is the dispersion coefficient of the reflective polarizing element, V1 is the dispersion coefficient of the first lens, and V2 is the dispersion coefficient of the second lens.

[0112] VQWP / (V2+V3)=0.76, wherein VQWP is the dispersion coefficient of the quarter wave plate, V3 is the dispersion coefficient of the third lens, and V2 is the dispersion coefficient of the second lens.

[0113] |f2 / f|=2.95, where f2 is the effective focal length of the second lens, and f is the effective focal length of the optical system.

[0114] f / f3-f / f1=0.27, wherein f is the effective focal length of the optical system, f1 is the effective focal length of the first lens, and f3 is the effective focal length of the third lens.

[0115] |R5 / CT3|=27.82, wherein R5 is the radius of curvature of the outer side surface of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

[0116] CT1 / CT2 / N1=0.37, wherein CT1 is the center thickness of the first lens on the optical axis, and N1 is the refractive index of the first lens.

[0117] (CT1+CT2+CT3) / TTL=0.70, wherein TTL is the on-axis distance from the outer side of the first lens to the display, CT1 is the center thickness of the first lens on the optical axis, CT2 is the center thickness of the second lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

[0118] 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 A4, A6, A8, and A10 of the aspherical mirror surfaces S4, S5, S6, S7, and S8 that can be used in Example 2.

[0119] Face number A4 A6 A8 A10 S4 -6.1614E-02 1.7339E-01 -2.4843E-02 7.8343E-02 S5 2.6900E-01 1.7790E-02 -1.4264E-01 4.7371E-02 S6 -1.6866E-01 -3.0515E-01 9.9349E-03 -9.4345E-03 S7 1.3929E-01 -4.9698E-04 -3.9605E-02 -4.7729E-03 S8 -3.2983E-02 -2.7075E-01 -1.9221E-01 -2.0574E-01

[0120] Table 6

[0121] Figure 6a 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 6b An astigmatism curve of the optical system of Example 2 is shown, which indicates meridional field curvature and sagittal field curvature. Figure 6cThe distortion curve of the optical system of Example 2 is shown, which represents the distortion magnitude value under different viewing angles. Figure 6d 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 6a to 6d It can be seen from the figure that the optical system provided in Example 2 can achieve good imaging quality. Specific embodiment 3

[0123] Figure 7 This is a schematic diagram of the structure of the optical system embodiment 3 of the present application. The optical system includes, 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 an imaging surface S9. Each of the first to third lenses has at least one outer side surface away from the display and one inner side surface close to the display; at least one of the first to third lenses has a partial reflective layer on its outer side surface or inner side surface.

[0124] Among them, the display emits a circularly polarized light (a quarter wave plate is attached in front of the display), which passes through the third lens, the second lens, the first lens and the quarter wave plate, becomes linearly polarized light, passes through the reflective polarization element and then reflects, 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.

[0125] As shown in Table 7, it is a basic parameter table of the optical system of Example 3, wherein the units of the radius of curvature, thickness, and focal length are all millimeters (mm).

[0126]

[0127]

[0128] Table 7

[0129] As shown in Table 8, in Example 3, the total effective focal length of the optical system is f=30.11 mm, the back focus BL of the optical system is 8.61 mm, and half of the maximum field of view of the optical system, semi-fov=53.0°.

[0130]

[0131] Table 8

[0132] The optical imaging lens in the third embodiment satisfies:

[0133] R4 / R5=0.57, where R5 is the radius of curvature of the outer side surface of the third lens, and R4 is the radius of curvature of the inner side surface of the second lens.

[0134] f23 / f=2.14, wherein f is the effective focal length of the optical system, and f23 is the combined focal length of the second lens and the third lens.

[0135] TD / tan(semi-fov)=16.07, wherein semi-fov is half of the maximum field of view of the optical system, and TD is the axial distance from the outer side surface of the first lens to the inner side surface of the third lens.

[0136] TD / BL=2.53, where BL is the back focus of the optical system, and TD is the axial distance from the outer side of the first lens to the inner side of the third lens.

[0137] VRP / (V1+V2)=0.76, wherein VRP is the dispersion coefficient of the reflective polarizing element, V1 is the dispersion coefficient of the first lens, and V2 is the dispersion coefficient of the second lens.

[0138] VQWP / (V2+V3)=0.76, wherein VQWP is the dispersion coefficient of the quarter wave plate, V3 is the dispersion coefficient of the third lens, and V2 is the dispersion coefficient of the second lens.

[0139] |f2 / f|=2.93, where f2 is the effective focal length of the second lens, and f is the effective focal length of the optical system.

[0140] f / f3-f / f1=0.28, wherein f is the effective focal length of the optical system, f1 is the effective focal length of the first lens, and f3 is the effective focal length of the third lens.

[0141] |R5 / CT3|=27.62, wherein R5 is the radius of curvature of the outer side surface of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

[0142] CT1 / CT2 / N1=0.38, wherein CT1 is the center thickness of the first lens on the optical axis, and N1 is the refractive index of the first lens.

[0143] (CT1+CT2+CT3) / TTL=0.71, wherein TTL is the on-axis distance from the outer side of the first lens to the display, CT1 is the center thickness of the first lens on the optical axis, CT2 is the center thickness of the second lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

[0144] 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 A4, A6, A8, and A10 of the aspherical mirror surfaces S4, S5, S6, S7, and S8 that can be used in Example 3.

[0145] Face number A4 A6 A8 A10 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

[0146] Table 9

[0147] Figure 8a 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. Figure 8b An astigmatism curve of the optical system of Example 3 is shown, which indicates meridional field curvature and sagittal field curvature. Figure 8c The distortion curve of the optical system of Example 3 is shown, which represents the distortion magnitude value under different viewing angles. Figure 8d 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 8a to 8d It can be seen from the figure that the optical system provided in Example 3 can achieve good imaging quality. Specific embodiment 4

[0149] Fig. 9 This is a schematic diagram of the structure of the optical system embodiment 4 of the present application. The optical system includes, 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 an imaging surface S9. Each of the first to third lenses has at least one outer side surface away from the display and one inner side surface close to the display; the outer side surface or the inner side surface of at least one lens of the first to third lenses has a partial reflective layer.

[0150] Among them, the display emits a circularly polarized light (a quarter wave plate is attached in front of the display), which passes through the third lens, the second lens, the first lens and the quarter wave plate, becomes linearly polarized light, passes through the reflective polarization element and then reflects, 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.

[0151] As shown in Table 10, it is a basic parameter table of the optical system of Example 4, wherein the units of the radius of curvature, thickness, and focal length are all millimeters (mm).

[0152]

[0153] Table 10

[0154] As shown in Table 11, in Example 4, the total effective focal length of the optical system is f=30.07 mm, the back focus of the optical system is BL=10.11 mm, and half of the maximum field of view of the optical system is semi-fov=53.0°.

[0155]

[0156]

[0157] Table 11

[0158] The optical imaging lens in the fourth embodiment satisfies:

[0159] R4 / R5=0.56, where R5 is the radius of curvature of the outer side surface of the third lens, and R4 is the radius of curvature of the inner side surface of the second lens.

[0160] f23 / f=21.61, wherein f is the effective focal length of the optical system, and f23 is the combined focal length of the second lens and the third lens.

[0161] TD / tan(semi-fov)=14.45, wherein semi-fov is half of the maximum field of view of the optical system, and TD is the axial distance from the outer side surface of the first lens to the inner side surface of the third lens.

[0162] TD / BL=1.90, where BL is the back focus of the optical system, and TD is the axial distance from the outer side of the first lens to the inner side of the third lens.

[0163] VRP / (V1+V2)=0.76, wherein VRP is the dispersion coefficient of the reflective polarizing element, V1 is the dispersion coefficient of the first lens, and V2 is the dispersion coefficient of the second lens.

[0164] VQWP / (V2+V3)=1.50, wherein VQWP is the dispersion coefficient of the quarter wave plate, V3 is the dispersion coefficient of the third lens, and V2 is the dispersion coefficient of the second lens.

[0165] |f2 / f|=9.50, wherein f2 is the effective focal length of the second lens, and f is the effective focal length of the optical system.

[0166] f / f3-f / f1=-0.16, wherein f is the effective focal length of the optical system, f1 is the effective focal length of the first lens, and f3 is the effective focal length of the third lens.

[0167] |R5 / CT3|=37.82, wherein R5 is the radius of curvature of the outer side surface of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

[0168] CT1 / CT2 / N1=4.39, wherein CT1 is the center thickness of the first lens on the optical axis, and N1 is the refractive index of the first lens.

[0169] (CT1+CT2+CT3) / TTL=0.65, wherein TTL is the on-axis distance from the outer side of the first lens to the display, CT1 is the center thickness of the first lens on the optical axis, CT2 is the center thickness of the second lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

[0170] In Example 4, 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 12 shows the high-order coefficients A4, A6, A8, and A10 of the aspherical mirror surfaces S4, S5, S6, S7, and S8 that can be used in Example 4.

[0171]

[0172]

[0173] Table 12

[0174] Fig.10a The axial chromatic aberration curve of the optical system of Example 4 is shown, which indicates the deviation of light of different wavelengths from the focal point behind the lens. Fig.10b An astigmatism curve of the optical system of Example 4 is shown, which indicates meridional field curvature and sagittal field curvature. Fig.10c The distortion curve of the optical system of Example 4 is shown, which represents the distortion magnitude value under different viewing angles. Fig.10d The relative illumination curve of the optical system of Example 4 is shown, which represents the relative illumination corresponding to different field angles on the imaging surface. Figures 10a to 10d As shown, the optical system provided in Example 4 can achieve good imaging quality. Specific embodiment 5

[0176] Fig.11 This is a schematic diagram of the structure of the optical system embodiment 5 of the present application. The optical system includes, 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 an imaging surface S9. Each of the first to third lenses has at least one outer side surface away from the display and one inner side surface close to the display; the outer side surface or the inner side surface of at least one lens of the first to third lenses has a partial reflective layer.

[0177] Among them, the display emits a circularly polarized light (a quarter wave plate is attached in front of the display), which passes through the third lens, the second lens, the first lens and the quarter wave plate, becomes linearly polarized light, passes through the reflective polarization element and then reflects, 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.

[0178] As shown in Table 13, it is a basic parameter table of the optical system of Example 5, wherein the units of the radius of curvature, thickness, and focal length are all millimeters (mm).

[0179]

[0180]

[0181] Table 13

[0182] As shown in Table 14, in Example 5, the total effective focal length of the optical system is f=30.07 mm, the back focus of the optical system is BL=10.09 mm, and half of the maximum field of view of the optical system is semi-fov=53.0°.

[0183]

[0184] Table 14

[0185] The optical imaging lens in the fifth embodiment satisfies:

[0186] R4 / R5=0.55, wherein R5 is the radius of curvature of the outer side surface of the third lens, and R4 is the radius of curvature of the inner side surface of the second lens.

[0187] f23 / f=21.22, wherein f is the effective focal length of the optical system, and f23 is the combined focal length of the second lens and the third lens.

[0188] TD / tan(semi-fov)=14.49, wherein semi-fov is half of the maximum field of view of the optical system, and TD is the axial distance from the outer side surface of the first lens to the inner side surface of the third lens.

[0189] TD / BL=1.91, where BL is the back focus of the optical system, and TD is the axial distance from the outer side surface of the first lens to the inner side surface of the third lens.

[0190] VRP / (V1+V2)=0.76, wherein VRP is the dispersion coefficient of the reflective polarizing element, V1 is the dispersion coefficient of the first lens, and V2 is the dispersion coefficient of the second lens.

[0191] VQWP / (V2+V3)=1.50, wherein VQWP is the dispersion coefficient of the quarter wave plate, V3 is the dispersion coefficient of the third lens, and V2 is the dispersion coefficient of the second lens.

[0192] |f2 / f|=9.38, where f2 is the effective focal length of the second lens, and f is the effective focal length of the optical system.

[0193] f / f3-f / f1=-0.16, wherein f is the effective focal length of the optical system, f1 is the effective focal length of the first lens, and f3 is the effective focal length of the third lens.

[0194] |R5 / CT3|=37.21, wherein R5 is the radius of curvature of the outer side surface of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

[0195] CT1 / CT2 / N1=4.39, wherein CT1 is the center thickness of the first lens on the optical axis, and N1 is the refractive index of the first lens.

[0196] (CT1+CT2+CT3) / TTL=0.65, wherein TTL is the on-axis distance from the outer side of the first lens to the display, CT1 is the center thickness of the first lens on the optical axis, CT2 is the center thickness of the second lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

[0197] In Example 5, 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 15 shows the high-order coefficients A4, A6, A8, and A10 of the aspherical mirror surfaces S4, S5, S6, S7, and S8 that can be used in Example 5.

[0198] Face number A4 A6 A8 A10 S4 -2.6881E-01 -1.2922E-01 1.0970E-01 2.5525E-02 S5 2.2770E-01 1.6278E-01 7.1019E-02 6.6719E-03 S6 1.6235E-01 2.2419E-01 9.8899E-02 -3.1348E-02 S7 -1.5901E-01 1.0397E-01 -8.0840E-02 5.8104E-03 S8 2.7500E-02 -2.5505E-01 -3.6861E-01 3.3742E-02

[0199] Table 15

[0200] Fig.12a The axial chromatic aberration curve of the optical system of Example 5 is shown, which indicates the deviation of light of different wavelengths from the focal point behind the lens. Figure 12b An astigmatism curve of the optical system of Example 5 is shown, which indicates meridional field curvature and sagittal field curvature. Fig.12c The distortion curve of the optical system of Example 5 is shown, which represents the distortion magnitude value under different viewing angles. Fig.12d The relative illumination curve of the optical system of Example 5 is shown, which represents the relative illumination corresponding to different field angles on the imaging surface. Figures 12a to 12d As shown, the optical system provided in Example 5 can achieve good imaging quality. Specific embodiment 6

[0202] Fig.13This is a schematic diagram of the structure of the optical system embodiment 6 of the present application. The optical system includes, 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 an imaging surface S9. Each of the first to third lenses has at least one outer side surface away from the display and one inner side surface close to the display; the outer side surface or the inner side surface of at least one lens of the first to third lenses has a partial reflective layer.

[0203] Among them, the display emits a circularly polarized light (a quarter wave plate is attached in front of the display), which passes through the third lens, the second lens, the first lens and the quarter wave plate, becomes linearly polarized light, passes through the reflective polarization element and then reflects, 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.

[0204] As shown in Table 16, it is a basic parameter table of the optical system of Example 6, wherein the units of the radius of curvature, thickness, and focal length are all millimeters (mm).

[0205]

[0206] Table 16

[0207] As shown in Table 17, in Example 6, the total effective focal length of the optical system is f=34.87 mm, the back focus of the optical system is BL=6.70 mm, and half of the maximum field of view of the optical system is semi-fov=53.0°.

[0208]

[0209] Table 17

[0210] The optical imaging lens in the sixth embodiment satisfies:

[0211] R4 / R5=1.18, wherein R5 is the radius of curvature of the outer side surface of the third lens, and R4 is the radius of curvature of the inner side surface of the second lens.

[0212] f23 / f=7.51, wherein f is the effective focal length of the optical system, and f23 is the combined focal length of the second lens and the third lens.

[0213] TD / tan(semi-fov)=14.65, wherein semi-fov is half of the maximum field of view of the optical system, and TD is the axial distance from the outer side surface of the first lens to the inner side surface of the third lens.

[0214] TD / BL=2.90, where BL is the back focus of the optical system, and TD is the axial distance from the outer side of the first lens to the inner side of the third lens.

[0215] VRP / (V1+V2)=0.89, wherein VRP is the dispersion coefficient of the reflective polarizing element, V1 is the dispersion coefficient of the first lens, and V2 is the dispersion coefficient of the second lens.

[0216] VQWP / (V2+V3)=1.03, wherein VQWP is the dispersion coefficient of the quarter wave plate, V3 is the dispersion coefficient of the third lens, and V2 is the dispersion coefficient of the second lens.

[0217] |f2 / f|=8.99, where f2 is the effective focal length of the second lens, and f is the effective focal length of the optical system.

[0218] f / f3-f / f1=0.11, wherein f is the effective focal length of the optical system, f1 is the effective focal length of the first lens, and f3 is the effective focal length of the third lens.

[0219] |R5 / CT3|=19.55, wherein R5 is the radius of curvature of the outer side surface of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

[0220] CT1 / CT2 / N1=2.84, wherein CT1 is the center thickness of the first lens on the optical axis, and N1 is the refractive index of the first lens.

[0221] (CT1+CT2+CT3) / TTL=0.73, wherein TTL is the on-axis distance from the outer side of the first lens to the display, CT1 is the center thickness of the first lens on the optical axis, CT2 is the center thickness of the second lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

[0222] In Example 6, 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 18 shows the high-order coefficients A4, A6, A8, and A10 of the aspherical mirror surfaces S4, S5, S6, S7, and S8 that can be used in Example 6.

[0223] Face number A4 A6 A8 A10 S4 -3.7153E-01 -4.4802E-02 -5.8708E-02 -7.3130E-02 S5 2.3781E-01 7.4424E-02 -1.3454E-01 -6.6143E-02 S6 5.3256E-02 1.5066E-01 -1.5517E-01 -1.3284E-02 S7 2.8881E-01 -1.6154E-02 -8.8647E-02 -6.4073E-03 S8 1.2345E-01 -2.7763E-02 -5.1112E-03 -6.6015E-03

[0224] Table 18

[0225] Fig.14a The axial chromatic aberration curve of the optical system of Example 6 is shown, which indicates the deviation of light of different wavelengths from the focal point behind the lens. Fig.14b An astigmatism curve of the optical system of Example 6 is shown, which indicates meridional field curvature and sagittal field curvature. Fig.14cThe distortion curve of the optical system of Example 6 is shown, which represents the distortion magnitude value under different viewing angles. Fig.14d The relative illumination curve of the optical system of Example 6 is shown, which represents the relative illumination corresponding to different field angles on the imaging surface. Figures 14a to 14d It can be seen from the figure that the optical system provided in Example 6 can achieve good imaging quality. Specific embodiment 7

[0227] Fig.15 This is a structural diagram of an optical system embodiment 7 of the present application, wherein the optical system includes, 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 an imaging surface S9. Each of the first to third lenses has at least one outer side surface away from the display and one inner side surface close to the display; and at least one of the first to third lenses has a partial reflective layer on its outer side surface or inner side surface.

[0228] Among them, the display emits a circularly polarized light (a quarter wave plate is attached in front of the display), which passes through the third lens, the second lens, the first lens and the quarter wave plate, becomes linearly polarized light, passes through the reflective polarization element and then reflects, 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.

[0229] As shown in Table 19, it is a basic parameter table of the optical system of Example 7, wherein the units of the radius of curvature, thickness, and focal length are all millimeters (mm).

[0230]

[0231]

[0232] Table 19

[0233] As shown in Table 20, in Example 7, the total effective focal length of the optical system is f=30.36 mm, the back focus BL of the optical system is 9.18 mm, and half of the maximum field of view angle of the optical system, semi-fov=53.0°.

[0234]

[0235] Table 20

[0236] The optical imaging lens in the seventh embodiment satisfies:

[0237] R4 / R5=1.02, wherein R5 is the radius of curvature of the outer side surface of the third lens, and R4 is the radius of curvature of the inner side surface of the second lens.

[0238] f23 / f=4.92, wherein f is the effective focal length of the optical system, and f23 is the combined focal length of the second lens and the third lens.

[0239] TD / tan(semi-fov)=13.17, wherein semi-fov is half of the maximum field of view of the optical system, and TD is the axial distance from the outer side surface of the first lens to the inner side surface of the third lens.

[0240] TD / BL=1.90, where BL is the back focus of the optical system, and TD is the axial distance from the outer side of the first lens to the inner side of the third lens.

[0241] VRP / (V1+V2)=0.51, wherein VRP is the dispersion coefficient of the reflective polarizing element, V1 is the dispersion coefficient of the first lens, and V2 is the dispersion coefficient of the second lens.

[0242] VQWP / (V2+V3)=0.76, wherein VQWP is the dispersion coefficient of the quarter wave plate, V3 is the dispersion coefficient of the third lens, and V2 is the dispersion coefficient of the second lens.

[0243] |f2 / f|=3.33, where f2 is the effective focal length of the second lens, and f is the effective focal length of the optical system.

[0244] f / f3-f / f1=-0.13, wherein f is the effective focal length of the optical system, f1 is the effective focal length of the first lens, and f3 is the effective focal length of the third lens.

[0245] |R5 / CT3|=38.46, wherein R5 is the radius of curvature of the outer side surface of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

[0246] CT1 / CT2 / N1=0.45, wherein CT1 is the center thickness of the first lens on the optical axis, and N1 is the refractive index of the first lens.

[0247] (CT1+CT2+CT3) / TTL=0.65, wherein TTL is the on-axis distance from the outer side of the first lens to the display, CT1 is the center thickness of the first lens on the optical axis, CT2 is the center thickness of the second lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

[0248] In Example 7, 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 21 shows the high-order coefficients A4, A6, A8, and A10 of the aspherical mirror surfaces S4, S5, S6, S7, and S8 that can be used in Example 7.

[0249] Face number A4 A6 A8 A10 S4 -2.5894E-01 6.2046E-02 1.1381E-01 3.0973E-02 S5 2.8157E-01 -7.9651E-03 1.8648E-02 2.2692E-02 S6 -2.6424E-01 -7.5703E-02 3.2181E-02 -6.5222E-02 S7 7.3736E-02 -4.4217E-02 5.3652E-02 2.1837E-02 S8 1.3903E-01 -3.7049E-02 -5.1200E-03 2.1125E-02

[0250] Table 21

[0251] Fig.16a The axial chromatic aberration curve of the optical system of Example 7 is shown, which indicates the deviation of light of different wavelengths from the focal point behind the lens. Fig.16b The astigmatism curve of the optical system of Example 7 is shown, which indicates the meridional field curvature and the sagittal field curvature. Fig.16c The distortion curve of the optical system of Example 7 is shown, which represents the distortion magnitude value under different viewing angles. Fig.16d The relative illumination curve of the optical system of Example 7 is shown, which represents the relative illumination corresponding to different field angles on the imaging surface. Figures 16a to 16d As shown, the optical system provided in Example 7 can achieve good imaging quality. Specific embodiment 8

[0253] Fig.17 This is a schematic diagram of the structure of the optical system embodiment 8 of the present application. The optical system includes, 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 an imaging surface S9. Each of the first to third lenses has at least one outer side surface away from the display and one inner side surface close to the display; and at least one of the first to third lenses has a partial reflective layer on the outer side surface or the inner side surface.

[0254] Among them, the display emits a circularly polarized light (a quarter wave plate is attached in front of the display), which passes through the third lens, the second lens, the first lens and the quarter wave plate, becomes linearly polarized light, passes through the reflective polarization element and then reflects, 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.

[0255] As shown in Table 22, it is a basic parameter table of the optical system of Example 8, wherein the units of the radius of curvature, thickness, and focal length are all millimeters (mm).

[0256]

[0257] Table 22

[0258] As shown in Table 23, in Example 8, the total effective focal length of the optical system is f=30.40 mm, the back focus BL of the optical system is 8.48 mm, and half of the maximum field of view angle of the optical system, semi-fov=53.0°.

[0259]

[0260] Table 23

[0261] The optical imaging lens in the eighth embodiment satisfies:

[0262] R4 / R5=1.01, wherein R5 is the radius of curvature of the outer side surface of the third lens, and R4 is the radius of curvature of the inner side surface of the second lens.

[0263] f23 / f=4.87, where f is the effective focal length of the optical system, and f23 is the combined focal length of the second lens and the third lens.

[0264] TD / tan(semi-fov)=13.58, wherein semi-fov is half of the maximum field of view of the optical system, and TD is the axial distance from the outer side surface of the first lens to the inner side surface of the third lens.

[0265] TD / BL=2.12, where BL is the back focus of the optical system, and TD is the axial distance from the outer side of the first lens to the inner side of the third lens.

[0266] VRP / (V1+V2)=0.51, wherein VRP is the dispersion coefficient of the reflective polarizing element, V1 is the dispersion coefficient of the first lens, and V2 is the dispersion coefficient of the second lens.

[0267] VQWP / (V2+V3)==0.76, wherein VQWP is the dispersion coefficient of the quarter wave plate, V3 is the dispersion coefficient of the third lens, and V2 is the dispersion coefficient of the second lens.

[0268] |f2 / f|=3.18, where f2 is the effective focal length of the second lens, and f is the effective focal length of the optical system.

[0269] f / f3-f / f1=-0.14, wherein f is the effective focal length of the optical system, f1 is the effective focal length of the first lens, and f3 is the effective focal length of the third lens.

[0270] |R5 / CT3|=38.13, wherein R5 is the radius of curvature of the outer side surface of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

[0271] CT1 / CT2 / N1=0.49, wherein CT1 is the center thickness of the first lens on the optical axis, and N1 is the refractive index of the first lens.

[0272] (CT1+CT2+CT3) / TTL=0.67, wherein TTL is the on-axis distance from the outer side of the first lens to the display, CT1 is the center thickness of the first lens on the optical axis, CT2 is the center thickness of the second lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

[0273] In Example 8, 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 24 shows the high-order coefficients A4, A6, A8, and A10 of the aspherical mirror surfaces S4, S5, S6, S7, and S8 that can be used in Example 8.

[0274] Face number A4 A6 A8 A10 S4 -2.3487E-01 1.1152E-01 1.3048E-01 3.3202E-02 S5 2.6863E-01 9.0567E-02 1.9499E-03 2.1137E-02 S6 -2.4497E-01 -1.1461E-01 -3.5037E-03 -7.7335E-02 S7 5.8905E-03 -7.1838E-02 3.1575E-02 1.9942E-02 S8 1.0094E-01 -2.3879E-02 -1.3684E-02 2.3331E-02

[0275] Table 24

[0276] Fig.18a The axial chromatic aberration curve of the optical system of Example 8 is shown, which indicates the deviation of light of different wavelengths from the focal point behind the lens. Fig.18b An astigmatism curve of the optical system of Example 8 is shown, which indicates meridional field curvature and sagittal field curvature. Fig.18c The distortion curve of the optical system of Example 8 is shown, which represents the distortion magnitude value under different viewing angles. Fig.18d The relative illumination curve of the optical system of Example 8 is shown, which represents the relative illumination corresponding to different field angles on the imaging surface. Figures 18a to 18d As shown, the optical system provided in Example 8 can achieve good imaging quality. Specific embodiment 9

[0278] Fig.19 This is a schematic diagram of the structure of the optical system embodiment 9 of the present application. The optical system includes, 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 an imaging surface S9. Each of the first to third lenses has at least one outer side surface away from the display and one inner side surface close to the display; and at least one of the first to third lenses has a partial reflective layer on the outer side surface or the inner side surface.

[0279] Among them, the display emits a circularly polarized light (a quarter wave plate is attached in front of the display), which passes through the third lens, the second lens, the first lens and the quarter wave plate, becomes linearly polarized light, passes through the reflective polarization element and then reflects, 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.

[0280] As shown in Table 25, it is a basic parameter table of the optical system of Example 9, wherein the units of the radius of curvature, thickness, and focal length are all millimeters (mm).

[0281]

[0282]

[0283] Table 25

[0284] As shown in Table 26, in Example 9, the total effective focal length of the optical system is f=30.70 mm, the back focus BL of the optical system is 30.70 mm, and half of the maximum field of view angle of the optical system is semi-fov=53.0°.

[0285]

[0286] Table 26

[0287] The optical imaging lens in the ninth embodiment satisfies:

[0288] R4 / R5=2.93, wherein R5 is the radius of curvature of the outer side surface of the third lens, and R4 is the radius of curvature of the inner side surface of the second lens.

[0289] f23 / f=6.12, wherein f is the effective focal length of the optical system, and f23 is the combined focal length of the second lens and the third lens.

[0290] TD / tan(semi-fov)=13.93, wherein semi-fov is half of the maximum field of view of the optical system, and TD is the axial distance from the outer side surface of the first lens to the inner side surface of the third lens.

[0291] TD / BL=2.28, where BL is the back focus of the optical system, and TD is the axial distance from the outer side surface of the first lens to the inner side surface of the third lens.

[0292] VRP / (V1+V2)=0.76, wherein VRP is the dispersion coefficient of the reflective polarizing element, V1 is the dispersion coefficient of the first lens, and V2 is the dispersion coefficient of the second lens.

[0293] VQWP / (V2+V3)=0.76, wherein VQWP is the dispersion coefficient of the quarter wave plate, V3 is the dispersion coefficient of the third lens, and V2 is the dispersion coefficient of the second lens.

[0294] |f2 / f|=16.82, where f2 is the effective focal length of the second lens, and f is the effective focal length of the optical system.

[0295] f / f3-f / f1=0.15, wherein f is the effective focal length of the optical system, f1 is the effective focal length of the first lens, and f3 is the effective focal length of the third lens.

[0296] |R5 / CT3|=20.90, wherein R5 is the radius of curvature of the outer side surface of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

[0297] CT1 / CT2 / N1=2.35, wherein CT1 is the center thickness of the first lens on the optical axis, and N1 is the refractive index of the first lens.

[0298] (CT1+CT2+CT3) / TTL=0.69, wherein TTL is the on-axis distance from the outer side of the first lens to the display, CT1 is the center thickness of the first lens on the optical axis, CT2 is the center thickness of the second lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

[0299] In Example 9, 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 27 shows the high-order coefficients A4, A6, A8, and A10 of the aspherical mirror surfaces S4, S5, S6, S7, and S8 that can be used in Example 9.

[0300] Face number A4 A6 A8 A10 S4 -3.2811E-01 1.0474E-01 8.3547E-02 3.2334E-02 S5 3.3830E-01 -2.3729E-02 -1.1123E-01 4.9376E-02 S6 -2.4618E-01 1.2666E-02 -2.3290E-01 5.9330E-02 S7 3.4149E-01 2.1810E-02 -9.0164E-02 -7.2288E-03 S8 1.9815E-01 -3.4108E-02 -1.9761E-02 -1.2540E-02

[0301] Table 27

[0302] Fig.20a The axial chromatic aberration curve of the optical system of Example 9 is shown, which indicates the deviation of light of different wavelengths from the focal point behind the lens. Fig.20b The astigmatism curve of the optical system of Example 9 is shown, which indicates the meridional field curvature and the sagittal field curvature. Fig.20c The distortion curve of the optical system of Example 9 is shown, which represents the distortion magnitude value under different viewing angles. Fig.20d The relative illumination curve of the optical system of Example 9 is shown, which represents the relative illumination corresponding to different field angles on the imaging surface. Figures 20a to 20d As shown, the optical system provided in Example 9 can achieve good imaging quality.

[0303] 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 optical system, characterized in that: The optical system comprises: a reflective polarizing element, a quarter wave plate, a first lens, a second lens, a third lens, and a display; The first lens to the third lens are arranged in sequence from the outer side to the inner side along the optical axis; The reflective polarizing element and the quarter-wave plate are placed outside the first lens; Each of the first to third lenses has at least one outer side surface away from the display and one inner side surface close to the display; The outer side surface or the inner side surface of at least one of the first lens to the third lens has a partial reflection layer; The curvature radius R5 of the outer side surface of the third lens and the curvature radius R4 of the inner side surface of the second lens satisfy: <R4 / R5。 2. The optical system according to claim 1, characterized in that The axial distance TD between half of the maximum field of view angle of the optical system (semi-fov) and the outer side surface of the first lens and the inner side surface of the third lens satisfies: 12 <TD / tan(semi-fov)<18。 3. The optical system according to claim 1, characterized in that The back focus BL of the optical system and the axial distance TD from the outer side of the first lens to the inner side of the third lens satisfy: 1.6 <TD / BL<3。 4. The optical system according to claim 1, characterized in that The dispersion coefficient VRP of the reflective polarizing element, the dispersion coefficient V1 of the first lens, and the dispersion coefficient V2 of the second lens satisfy: 0 <VRP / (V1+V2)<1。 5. The optical system according to claim 1, characterized in that The partial reflective layer of the third lens is plated on the outer side surface or the inner side surface of the third lens.

6. An optical system, characterized in that: The optical system comprises: a reflective polarizing element, a quarter wave plate, a first lens, a second lens, a third lens, and a display; The first lens to the third lens are arranged in sequence from the outer side to the inner side along the optical axis; The reflective polarizing element and the quarter-wave plate are placed outside the first lens; Each of the first to third lenses has at least one outer side surface away from the display and an inner side surface close to the display; The outer side or the inner side of the at least one lens has a partially reflective layer; Wherein, the effective focal length f of the imaging system and the combined focal length f23 of the second lens and the third lens satisfy: 1 <f23 / f<23。 7. The optical imaging lens according to claim 6, wherein: The axial distance TD between half of the maximum field of view angle of the optical system (semi-fov) and the outer side surface of the first lens and the inner side surface of the third lens satisfies: 12 <TD / tan(semi-fov)<18。 8. The optical imaging lens according to claim 6, wherein: The back focus BL of the optical system and the axial distance TD from the outer side of the first lens to the inner side of the third lens satisfy: 1.6 <TD / BL<3。 9. The optical imaging lens according to claim 6, wherein: The dispersion coefficient VRP of the reflective polarizing element, the dispersion coefficient V1 of the first lens, and the dispersion coefficient V2 of the second lens satisfy: 0 <VRP / (V1+V2)<1。 10. The optical imaging lens according to claim 6, wherein: The partial reflective layer of the third lens is plated on the outer side surface or the inner side surface of the third lens.

Images