Optical assembly

Abstract

The utility model discloses an optical assembly, which comprises a lens cone, an optical element group and a spacer group, wherein the optical element group and the spacer group are arranged in the lens cone; the optical element group sequentially comprises a first lens, a second lens, a third lens and a fourth lens from the first side to the second side along the optical axis, the second lens has positive focal power, and the second side surface of the second lens is a convex surface; the first side surface of the third lens is a concave surface, and the second side surface of the third lens is a convex surface; the first side surface of the fourth lens is a convex surface, and the second side surface of the fourth lens is a convex surface; the spacer group includes a first spacer in contact with the second side surface of the first lens and a second spacer in contact with the second side surface of the second lens; the interval EP01 between the first side end face of the lens barrel and the first spacer along the optical axis, the maximum thickness CP1 of the first spacer and the center thickness CT1 of the first lens on the optical axis satisfy: 4.5 lt; (EP01 + CP1) / CT1lt; 6.3); the effective focal length f2 of the second lens, the outer diameter D1s of the first side surface of the first spacer and the outer diameter D2s of the first side surface of the second spacer satisfy the following conditions: 1.0 lt; f2 / (D2s + D1s) lt; 2.2.

Description

Technical Field

[0001] The present application relates to the field of optical devices, and in particular to a catadioptric optical component. Background Art

[0002] Virtual reality technology is a new practical technology that has moved from theory to reality and has been widely used in education, military, art and entertainment, medical care, and automobiles.

[0003] Early virtual reality devices included aspherical or Fresnel lenses, which had problems such as long body length, heavy weight, and forward center of gravity, which would affect the wearing comfort of users. In order to improve the wearing comfort of users, virtual reality devices are usually configured as a catadioptric optical system with three lenses. However, the external field of view of the catadioptric optical system with three lenses is relatively blurry and the image quality is poor. Utility Model Content

[0004] The present application provides an optical component that can at least solve or partially solve at least one problem or other problems existing in the prior art.

[0005] One aspect of the present application provides an optical component, which includes a lens barrel and an optical element group and a spacer group placed in the lens barrel; the optical element group includes, in order from the first side to the second side along the optical axis: a first lens, whose first side surface is a plane and whose second side surface is a plane; a second lens with positive optical power, whose second side surface is a convex surface; a third lens with negative optical power, whose first side surface is a concave surface and whose second side surface is a convex surface; a fourth lens with positive optical power, whose first side surface is a convex surface and whose second side surface is a convex surface; the optical element group also includes a linear polarization element, a reflective polarization element, a quarter-wave plate and a partial reflection layer; at least one of the first lens to the fourth lens At least one surface of the lens is a thin Fresnel surface; the spacer group includes a first spacer disposed on the second side surface of the first lens and in contact with the second side surface of the first lens, and a second spacer disposed on the second side surface of the second lens and in contact with the second side surface of the second lens; wherein the interval EP01 between the first side end surface of the lens barrel and the first spacer along the optical axis, the maximum thickness CP1 of the first spacer and the center thickness CT1 of the first lens on the optical axis satisfy: 4.5<(EP01+CP1) / CT1<6.3; the effective focal length f2 of the second lens, the outer diameter D1s of the first side surface of the first spacer and the outer diameter D2s of the first side surface of the second spacer satisfy: 1.0 <f2 / (D2s+D1s)<2.2。

[0006] According to an exemplary embodiment of the present application, the curvature radius R4 of the second side surface of the second lens, the refractive index N2 of the second lens, and the inner diameter d2s of the first side surface of the second spacer satisfy: -2.5 <R4×N2 / d2s<-1.5。

[0007] According to an exemplary embodiment of the present application, the center thickness CT2 of the second lens on the optical axis, the Abbe number V2 of the second lens, the maximum thickness CP1 of the first spacer and the maximum thickness CP2 of the second spacer satisfy: 36.0 <CT2×V2 / (CP1+CP2)<66.0。

[0008] According to an exemplary embodiment of the present application, the center thickness CT2 of the second lens on the optical axis, the on-axis distance T12 from the second side surface of the first lens to the first side surface of the second lens, and the interval EP12 between the first spacer and the second spacer along the optical axis satisfy: 1.0<(CT2+T12) / EP12<1.8.

[0009] According to an exemplary embodiment of the present application, the radius of curvature R5 of the first side surface of the third lens, the inner diameter d2m of the second side surface of the second spacer, and the outer diameter D2m of the second side surface of the second spacer satisfy: -33.0 <R5 / (D2m-d2m)<-22.0。

[0010] According to an exemplary embodiment of the present application, the spacer set further includes a third spacer disposed on the second side surface of the third lens and in contact with the second side surface of the third lens, wherein the curvature radius R6 of the second side surface of the third lens, the inner diameter d3s of the first side surface of the third spacer, and the outer diameter D3s of the second side surface of the third spacer satisfy: -3.5 <R6 / d3s+R6 / D3s<-2.0。

[0011] According to an exemplary embodiment of the present application, the spacer group also includes a third spacer disposed on the second side of the third lens and in contact with the second side of the third lens, wherein the center thickness CT3 of the third lens on the optical axis, the Abbe number V3 of the third lens, the maximum thickness CP2 of the second spacer, and the maximum thickness CP3 of the third spacer satisfy: 4.0≤CT3×V3 / (CP2+CP3)≤11.1.

[0012] According to an exemplary embodiment of the present application, the spacer set further includes a third spacer disposed on the second side surface of the third lens and in contact with the second side surface of the third lens, wherein the effective focal length f3 of the third lens and the inner diameter d3s of the first side surface of the third spacer satisfy: -4.0 <f3 / d3s<-2.5。

[0013] According to an exemplary embodiment of the present application, the spacer group also includes a third spacer disposed on the second side of the third lens and in contact with the second side of the third lens, wherein the center thickness CT3 of the third lens on the optical axis, the axial distance T23 from the second side of the second lens to the first side of the third lens, and the interval EP23 between the second spacer and the third spacer along the optical axis satisfy: 1.2<(CT3+T23) / EP23≤2.7.

[0014] According to an exemplary embodiment of the present application, the length L of the lens barrel in the direction of the optical axis, the center thickness CT4 of the fourth lens on the optical axis, and the axial distance T34 from the second side surface of the third lens to the first side surface of the fourth lens satisfy: 1.5 <L / (CT4+T34)<3.0。

[0015] According to an exemplary embodiment of the present application, the spacer group further includes a third spacer disposed on the second side surface of the third lens and in contact with the second side surface of the third lens, wherein the effective focal length f4 of the fourth lens and the outer diameter D3m of the second side surface of the third spacer satisfy: 1.4 <f4 / D3m<1.9。

[0016] According to an exemplary embodiment of the present application, the spacer group also includes a third spacer disposed on the second side of the third lens and in contact with the second side of the third lens, wherein the curvature radius R8 of the second side of the fourth lens, the inner diameter d3m of the second side of the third spacer, and the outer diameter D3m of the second side of the third spacer satisfy: -40.0≤R8 / (D3m-d3m)<-10.0.

[0017] The optical assembly provided in the present application uses four lenses. By making (EP01+CP1) / CT1 within the range of 4.5 to 6.3, the optical assembly can have good bearing stability. However, the center thickness of the first lens will be limited, which will cause the field curvature of the optical assembly to deteriorate, affecting the imaging quality of the optical assembly. Therefore, by controlling the relationship between the effective focal length of the second lens, the outer diameter of the first side of the first spacer, and the outer diameter of the first side of the second spacer, the effective focal length of the second lens can be within a reasonable range, and the second lens can generate negative spherical aberration, which is balanced with the positive spherical aberration generated by other lenses, thereby reducing the field curvature of the optical assembly and ensuring that the optical assembly has good imaging quality; at the same time, the outer diameter of the first side of the second spacer can be constrained, and on the basis of ensuring its bearing function, the processability of the second spacer is improved and the assembly stability of the second lens is ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings, in which:

[0019] Figure 1 shows a schematic structural diagram of an optical component according to the present application;

[0020] Figure 2 A schematic diagram of the optical path of the optical components according to embodiments 1 and 2 of the present application is shown;

[0021] Figure 3 A schematic structural diagram of an optical component according to Embodiment 1 of the present application is shown;

[0022] Figure 4 A schematic structural diagram of an optical component according to Embodiment 2 of the present application is shown;

[0023] FIG. 5A to FIG. 5C The axial chromatic aberration curve, astigmatism curve and distortion curve of the optical components according to embodiments 1 and 2 of the present application are shown;

[0024] Figure 6 A schematic diagram of the optical path of the optical assembly according to Embodiments 3 and 4 of the present application is shown;

[0025] Figure 7 A schematic structural diagram of an optical component according to Embodiment 3 of the present application is shown;

[0026] Figure 8 A schematic structural diagram of an optical component according to Embodiment 4 of the present application is shown;

[0027] 9A to 9C The axial chromatic aberration curve, astigmatism curve and distortion curve of the optical components according to Embodiments 3 and 4 of the present application are shown;

[0028] Fig.10 Schematic diagram of the optical path of the optical assembly according to Embodiments 5 and 6 of the present application is shown;

[0029] Fig.11 A schematic structural diagram of an optical component according to Embodiment 5 of the present application is shown;

[0030] Fig.12 shows a schematic structural diagram of an optical component according to Embodiment 6 of the present application; and

[0031] FIG. 13A to FIG. 13C The axial chromatic aberration curve, astigmatism curve and distortion curve of the optical components according to Examples 5 and 6 of the present application are shown. DETAILED DESCRIPTION

[0032] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application, and do not limit the scope of the present application in any way. Throughout the specification, the same figure numerals refer to the same elements.

[0033] 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.

[0034] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are 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 for illustration only and are not drawn strictly to scale.

[0035] In this article, 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 first side (e.g., the human eye side) is called the first side surface of the lens, and the surface of each lens closest to the second side (e.g., the display screen side) is called the second side surface of the lens.

[0036] It should also be understood that the terms "include", "comprising", "having", "including" 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 describing embodiments of the present application, the term "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.

[0037] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as those 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 sense unless explicitly defined in this article.

[0038] 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 present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0039] The features, principles and other aspects of the present application are described in detail below.

[0040] The first aspect of the present application provides such an optical component, which may include an optical element group, which may include a first lens, a second lens, a third lens and a fourth lens arranged in sequence from a first side to a second side along an optical axis. There may be air spaces between adjacent lenses of the first lens to the fourth lens.

[0041] In example embodiments, the first side surface of the first lens may be a plane, and the second side surface may be a plane.

[0042] In an exemplary embodiment, the second lens may have positive optical power, and the second side surface thereof may be convex.

[0043] In example embodiments, the third lens may have negative power, a first side surface thereof may be a concave surface, and a second side surface thereof may be a convex surface.

[0044] In example embodiments, the fourth lens may have positive power, a first side surface thereof may be a convex surface, and a second side surface thereof may be a convex surface.

[0045] In an exemplary embodiment, the optical element group may further include a linear polarizing element, a reflective polarizing element, a quarter wave plate, and a partial reflective layer. The linear polarizing element may be attached to the first side surface of the first lens. The partial reflective layer may be attached to the second side surface of the fourth lens. The partial reflective layer has a semi-transmissive and semi-reflective effect on light, and the partial reflective layer, combined with the reflective polarizing element and the quarter wave plate, can refract the light multiple times, effectively reducing the main body length of the optical component.

[0046] As an example, the reflective polarizing element may be attached to the first side surface of the second lens. The quarter wave plate may be attached to the first side surface of the fourth lens.

[0047] As an example, the reflective polarizing element and the quarter wave plate are bonded together to form a film layer, and the bonded film layer is attached to the first side surface of the second lens, wherein the reflective polarizing element is located on the first side surface of the quarter wave plate. By bonding the reflective polarizing element and the quarter wave plate together to form a film layer, the number of attached surfaces of the film layer can be reduced, and the attachment yield of the film layer can be improved.

[0048] In an exemplary embodiment, at least one surface of at least one of the first to fourth lenses is a thin Fresnel surface. The use of a thin Fresnel surface can reduce the weight of the entire optical assembly.

[0049] In an exemplary embodiment, the optical component may further include a spacer group. The spacer group may include at least one of a first spacer, a second spacer, and a third spacer. The first spacer may be placed on the second side of the first lens and at least partially contact the second side of the first lens; the second spacer may be placed on the second side of the second lens and at least partially contact the second side of the second lens; the third spacer may be placed on the second side of the third lens and at least partially contact the second side of the third lens. Reasonable use of spacers can effectively avoid stray light risks, reduce interference with image quality, and thereby improve the imaging quality of the optical component.

[0050] In an exemplary embodiment, the optical assembly may further include a lens barrel, wherein the optical element group and the spacer group are both disposed in the lens barrel.

[0051] In an exemplary embodiment, the first side may be the human eye side, and the second side may be the display screen side. Accordingly, the first side of each element (first lens, second lens, third lens, fourth lens) may be referred to as the side near the human eye, and the second side may be referred to as the side near the screen.

[0052] In an exemplary embodiment, the optical assembly may further include an aperture, which is disposed between the first side and the first lens. Specifically, the aperture is disposed between the first side and the linear polarization element. The image light on the display screen is refracted and reflected multiple times by the fourth lens, the third lens, the second lens, the quarter wave plate, the reflective polarization element, the first lens, the linear polarization element, etc., and is finally projected to the user's eyes.

[0053] In an exemplary embodiment, the second side of the optical component may be provided with an image surface, and the image surface may be provided with a display screen, for example. The image light from the display screen may sequentially pass through the fourth lens, the quarter wave plate, the third lens, and the second lens, and reach the reflective polarizing element located on the first side of the second lens, and then reflect at the reflective polarizing element to form a first reflected image light. The first reflected image light passes through the second lens, the quarter wave plate, the third lens, and the fourth lens, and reaches the partial reflective layer located on the second side of the fourth lens, and then reflects at the partial reflective layer to form a second reflected image light. The second reflected image light sequentially passes through the fourth lens, the quarter wave plate, the third lens, the second lens, the reflective polarizing element, the first lens, the linear polarizing element to the aperture and is finally projected into the eyes of the user. The optical component provided in the present application folds the required optical path without affecting the projection quality by combining light reflection and refraction, effectively shortening the main body length of the optical component.

[0054] In an exemplary embodiment, the interval EP01 along the optical axis between the first side end face of the lens barrel and the first spacer, the maximum thickness CP1 of the first spacer, and the central thickness CT1 of the first lens on the optical axis may satisfy: 4.5 < (EP01 + CP1) / CT1 < 6.3. By reasonably controlling the relationship among the interval along the optical axis between the first side end face of the lens barrel and the first spacer, the maximum thickness of the first spacer, and the central thickness of the first lens on the optical axis, the bearing stability of the optical component can be improved.

[0055] In an exemplary embodiment, the effective focal length f2 of the second lens, the outer diameter D1s of the first side face of the first spacer, and the outer diameter D2s of the first side face of the second spacer may satisfy: 1.0 < f2 / (D2s + D1s) < 2.2. When (EP01 + CP1) / CT1 is in the range of 4.5 to 6.3, the central thickness of the first lens will be restricted, resulting in deterioration of the field curvature of the optical component and affecting the imaging quality of the optical component. Therefore, by controlling the relationship among the effective focal length of the second lens, the outer diameter of the first side face of the first spacer, and the outer diameter of the first side face of the second spacer, the effective focal length of the second lens can be within a reasonable range, and the second lens can generate negative spherical aberration. The negative spherical aberration generated by the second lens balances the positive spherical aberration generated by other lenses, thereby reducing the field curvature of the optical component and ensuring that the optical component has good imaging quality. At the same time, it is also possible to restrict the outer diameter of the first side face of the second spacer, improve the processability of the second spacer on the basis of ensuring its bearing effect, and ensure the assembly stability of the second lens.

[0056] The following table is the assembly deformation analysis table of the second lens. Among them, the value of (EP01 + CP1) / CT1 for Sample 1 is 5.1, and the value of f2 / (D2s + D1s) is 1.8; the value of (EP01 + CP1) / CT1 for Sample 2 is 3.2, and the value of f2 / (D2s + D1s) is 0.4; the value of (EP01 + CP1) / CT1 for Sample 3 is 12, and the value of f2 / (D2s + D1s) is 5.6.

[0057]

[0058] As can be seen from the above table, compared with Sample 2 and Sample 3, the displacement of the center point of the second lens in Sample 1 is smaller. It can be seen that by making the optical component satisfy "4.5 < (EP01 + CP1) / CT1 < 6.3" and "1.0 < f2 / (D2s + D1s) < 2.2", it is possible to ensure that the second lens has a smaller deformation amount, thereby improving the assembly stability of the second lens.

[0059] In an exemplary embodiment, the radius of curvature R4 of the second side surface of the second lens, the refractive index N2 of the second lens, and the inner diameter d2s of the first side surface of the second spacer may satisfy: -2.5 < R4×N2 / d2s < -1.5. By controlling the mutual relationship among the radius of curvature of the second side surface of the second lens, the refractive index of the second lens, and the inner diameter of the first side surface of the second spacer, the deflection angle of light passing through the second lens and the optical power of the second lens can be reasonably constrained, thereby constraining the field curvature of the optical assembly and improving the processability of the second lens; at the same time, it can also ensure that the inner diameter of the second spacer matches the refractive performance of the second lens, preventing non-effective light from deflecting out and causing stray light risks.

[0060] In an exemplary embodiment, the central thickness CT2 of the second lens on the optical axis, the Abbe number V2 of the second lens, the maximum thickness CP1 of the first spacer, and the maximum thickness CP2 of the second spacer may satisfy: 36.0 < CT2×V2 / (CP1 + CP2) < 66.0. By controlling the mutual relationship among the central thickness and Abbe number of the second lens and the maximum thicknesses of the first spacer and the second spacer, the chromatic aberration of the optical assembly can be corrected and the imaging quality of the optical assembly can be improved; at the same time, it can also make the central thickness of the second lens, the maximum thicknesses of the first spacer and the second spacer respectively within a reasonable range, which is beneficial to the molding of the second lens and indirectly constrains the overall length of the optical assembly, which is beneficial to shortening the body length of the optical assembly.

[0061] In an exemplary embodiment, the central thickness CT2 of the second lens on the optical axis, the axial distance T12 from the second side surface of the first lens to the first side surface of the second lens, and the axial spacing EP12 of the first spacer and the second spacer along the optical axis may satisfy: 1.0 < (CT2 + T12) / EP12 < 1.8. By controlling the mutual relationship among the central thickness of the second lens on the optical axis, the axial distance from the second side surface of the first lens to the first side surface of the second lens, and the axial spacing of the first spacer and the second spacer along the optical axis, the central thickness, air gap, and edge thickness of the second lens can be respectively constrained within a reasonable range, ensuring good processability of the second lens while ensuring the self-structural strength of the second lens.

[0062] In an exemplary embodiment, the radius of curvature R5 of the first side surface of the third lens, the inner diameter d2m of the second side surface of the second spacer, and the outer diameter D2m of the second side surface of the second spacer may satisfy: -33.0 < R5 / (D2m - d2m) < -22.0. By controlling the ratio of the radius of curvature of the first side surface of the third lens to the difference between the inner and outer diameters of the second side surface of the second spacer, the refractive performance of the second spacer and the second lens to light can be made to match, preventing problems such as stray light risks caused by non-effective light deflecting out and light efficiency reduction caused by the second spacer blocking effective light.

[0063] In an exemplary embodiment, the radius of curvature R6 of the second side surface of the third lens, the inner diameter d3s of the first side surface of the third spacer, and the outer diameter D3s of the second side surface of the third spacer may satisfy: -3.5 < R6 / d3s + R6 / D3s < -2.0. By controlling the radius of curvature of the second side surface of the third lens and the relationship between the inner and outer diameters of the first side surface of the third spacer, the shape of the third lens can be constrained, the sensitivity of the third lens can be reduced, and the assembly yield of the optical component can be improved; at the same time, the refractive performance of light of the third spacer and the third lens can be matched, preventing problems such as stray light risk caused by non-effective light rays deviating and light efficiency reduction caused by the third spacer blocking effective light rays.

[0064] In an exemplary embodiment, the central thickness CT3 of the third lens on the optical axis, the Abbe number V3 of the third lens, the maximum thickness CP2 of the second spacer, and the maximum thickness CP3 of the third spacer may satisfy: 4.0 ≤ CT3×V3 / (CP2 + CP3) ≤ 11.1. Reasonably controlling the relationship between the central thickness of the third lens on the optical axis, the Abbe number of the third lens, the maximum thickness of the second spacer, and the maximum thickness of the third spacer is beneficial to reducing the overall chromatic aberration of the optical component and improving the imaging quality of the optical component.

[0065] In an exemplary embodiment, the effective focal length f3 of the third lens and the inner diameter d3s of the first side surface of the third spacer may satisfy: -4.0 < f3 / d3s < -2.5. By controlling the ratio of the effective focal length of the third lens to the inner diameter of the first side surface of the third spacer, the shape of the third lens can be constrained, the sensitivity of the third lens can be reduced, and the assembly yield of the optical component can be improved; at the same time, the inner diameter of the first side surface of the third spacer can be constrained within a reasonable range to limit the generation of stray light.

[0066] In an exemplary embodiment, the central thickness CT3 of the third lens on the optical axis, the on-axis distance T23 from the second side surface of the second lens to the first side surface of the third lens, and the interval EP23 between the second spacer and the third spacer along the optical axis may satisfy: 1.2 < (CT3 + T23) / EP23 ≤ 2.7. By controlling the relationship between the central thickness of the third lens on the optical axis, the on-axis distance from the second side surface of the second lens to the first side surface of the third lens, and the interval between the second spacer and the third spacer along the optical axis, the central thickness and edge thickness of the third lens can be constrained within a reasonable range, which is beneficial to the forming of the third lens; at the same time, the field curvature can be controlled by limiting the air interval between the second lens and the third lens, thereby improving the imaging quality of the optical component.

[0067] In an exemplary embodiment, the length L of the lens barrel in the direction of the optical axis, the central thickness CT4 of the fourth lens on the optical axis, and the on-axis distance T34 from the second side surface of the third lens to the first side surface of the fourth lens may satisfy: 1.5 < L / (CT4 + T34) < 3.0. By controlling the mutual relationship among the length of the lens barrel in the direction of the optical axis, the central thickness of the fourth lens on the optical axis, and the on-axis distance from the second side surface of the third lens to the first side surface of the fourth lens, the distortion contribution of each field of view of the optical component can be constrained within a reasonable range. Combining with adjusting the air gap size between the lenses, the imaging quality of the optical component can be improved; meanwhile, it is also beneficial to constrain the positional relationship between the fourth lens and the lens barrel, and improve the imaging clarity of the optical component.

[0068] In an exemplary embodiment, the effective focal length f4 of the fourth lens and the outer diameter D3m of the second side surface of the third spacer may satisfy: 1.4 < f4 / D3m < 1.9. By controlling the ratio of the effective focal length of the fourth lens to the outer diameter of the second side surface of the third spacer, the effective focal length of the fourth lens can be within a reasonable range, and the fourth lens can generate negative spherical aberration. The negative spherical aberration generated by the fourth lens is balanced with the positive spherical aberration generated by other lenses, so that the optical component has good imaging quality; at the same time, the outer diameter of the second side surface of the third spacer can also be constrained, and on the basis of ensuring its supporting function, the processability of the third spacer can be improved.

[0069] In an exemplary embodiment, the radius of curvature R8 of the second side surface of the fourth lens, the inner diameter d3m of the second side surface of the third spacer, and the outer diameter D3m of the second side surface of the third spacer may satisfy: -40.0 ≤ R8 / (D3m - d3m) < -10.0. By controlling the ratio of the radius of curvature of the second side surface of the fourth lens to the difference between the inner and outer diameters of the second side surface of the third spacer, the refractive performance of the third spacer and the third lens to light can be matched, preventing problems such as stray light risk caused by non-effective light deviation and light efficiency reduction caused by the third spacer blocking the effective light.

[0070] The optical component according to the above embodiment of the present application may employ multiple lenses, such as the four lenses described above. By reasonably allocating the parameters of each lens, the lens barrel, and each spacer, the body length of the optical component can be reduced, and the assembly stability, assembly yield, and imaging quality of the optical component can be improved. The optical component configured as above has characteristics such as miniaturization and good imaging quality, can well meet the use requirements of various portable electronic products in the projection scenario, and the center of gravity of the optical component and the device including the optical component moves backward, improving the wearing comfort of the user.

[0071] In an embodiment of the present application, at least one of the surfaces of each of the first lens to the fourth lens is an aspherical surface. The characteristic of an aspherical lens is that the curvature continuously changes from the center of the lens to the periphery of the lens. Different from a spherical lens with a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has better curvature radius characteristics and has the advantages of improving distortion aberration and astigmatism aberration. After using an aspherical lens, it is possible to eliminate the aberration that appears during imaging as much as possible, thereby improving the imaging quality.

[0072] 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 component can be changed to obtain the various results and advantages described in this specification.

[0073] A second aspect of the present application provides such an optical component, which may include a lens barrel, and an optical element group and a spacer group disposed in the lens barrel. The optical element group sequentially includes, along the optical axis, from the first side to the second side: a first lens, whose first side is a plane and the second side is a plane; a second lens with positive optical power, whose second side is convex; a third lens with negative optical power, whose first side is concave and the second side is convex; a fourth lens with positive optical power, whose first side is convex and the second side is convex. The optical element group further includes a linear polarization element, a reflective polarizing element, a quarter-wave plate, and a partial reflection layer. At least one surface of at least one of the first lens to the fourth lens is a thin Fresnel surface. The spacer group includes a third spacer disposed on and in contact with the second side of the third lens.

[0074] Wherein, the effective focal length f4 of the fourth lens and the outer diameter D3m of the second side of the third spacer may satisfy: 1.4 < f4 / D3m < 1.9. By controlling the ratio of the effective focal length of the fourth lens to the outer diameter of the second side of the third spacer, it is possible to make the effective focal length of the fourth lens within a reasonable range, and make the fourth lens generate negative spherical aberration, and the negative spherical aberration generated by the fourth lens balances the positive spherical aberration generated by other lenses, so that the optical component has good imaging quality; at the same time, it is also possible to restrict the outer diameter of the second side of the third spacer, and improve the processability of the third spacer on the basis of ensuring its supporting effect.

[0075] The following further describes specific embodiments of the optical component applicable to the above embodiments with reference to the accompanying drawings.

[0076] Example 1

[0077] The following refers to Figure 2 and Figure 3 Describe the optical component according to Embodiment 1 of the present application.

[0078] As Figure 3 As shown, the optical assembly may include a lens barrel P0 and an optical element group and a spacer group placed in the lens barrel P0. The optical element group may include a linear polarization element LP, a first lens E1, a reflective polarization element RP, a second lens E2, a third lens E3, a quarter wave plate QWP, a fourth lens E4 and a partial reflection layer BS arranged in sequence from the first side to the second side along the optical axis. A stop STO may also be provided between the first side and the linear polarization element LP. The spacer group may also include a first spacer P1, a second spacer P2 and a third spacer P3. In the present embodiment, the first side refers to the human eye side, and the second side refers to the display screen side. The first side of each element (the first lens E1, the second lens E2, the third lens E3, the fourth lens E4) is referred to as the near human eye side, and the second side is referred to as the near screen side.

[0079] The side S1 of the first lens E1 near the human eye is a plane, and the side S2 near the screen is a plane. The second lens E2 has positive focal power, and its side S3 near the human eye is a concave surface, and the side S4 near the screen is a convex surface. The third lens E3 has negative focal power, and its side S5 near the human eye is a concave surface, and the side S6 near the screen is a convex surface. The fourth lens E4 has positive focal power, and its side S7 near the human eye is a convex surface, and the side S8 near the screen is a convex surface. The linear polarization element LP is attached to the side S1 near the human eye of the first lens E1. The reflective polarization element RP is attached to the side S3 near the human eye of the second lens E2. The quarter-wave plate QWP is attached to the side S7 near the human eye of the fourth lens E4. The partial reflection layer BS is attached to the side S8 near the screen of the fourth lens E4.

[0080] In this example, the second side of the optical component may be provided with an image surface S9 (not shown), and the image surface S9 may be provided with a display screen, for example. Figure 2 As shown, the image light from the image surface S9 passes through the fourth lens E4, the quarter wave plate QWP, the third lens E3, the second lens E2 in sequence and reaches the reflective polarizer RP located on the side of the second lens E2 near the human eye, and then undergoes a first reflection at the reflective polarizer RP. The light reflected for the first time passes through the second lens E2, the third lens E3, the quarter wave plate QWP, the fourth lens E4 and reaches the partial reflective layer BS located on the side of the fourth lens E4 near the screen, and then undergoes a second reflection at the partial reflective layer BS. The light reflected for the second time passes through the fourth lens E4, the quarter wave plate QWP, the third lens E3, the second lens E2, the reflective polarizer RP, the first lens E1, the linear polarizer LP to the aperture STO in sequence and is finally projected into the user's eyes. For example, the light of the optical component after two reflections is finally projected into the user's eyes.

[0081] Table 1 shows the basic parameters of the optical components of Example 1, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm). The image light from the image surface S9 passes through the components in the order of sequence number 25 to sequence number 1 and is finally projected into the human eye.

[0082]

[0083] Table 1

[0084] In this embodiment, the effective focal length f2 of the second lens is 129.14 mm, the effective focal length f3 of the third lens is -169.35 mm, and the effective focal length f4 of the fourth lens is 75.52 mm.

[0085] In this embodiment, the side surface S3 near the human eye of the second lens E2, the side surface S7 near the human eye and the side surface S8 near the screen of the fourth lens E4 are all aspherical surfaces, the side surface S4 near the screen of the second lens E2, the side surface S5 near the human eye and the side surface S6 near the screen of the third lens E3 are all thin Fresnel surfaces, and the surface shape x of each aspherical lens or thin Fresnel lens can be defined by but not limited to the following aspherical surface formula:

[0086]

[0087] 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 above); k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. Table 2 shows the cone coefficient k and the high-order coefficients A4, A6, A8, A9 that can be used for each aspheric surface or thin Fresnel surface S3-S8 in Example 1. 10 , A 12 and A 14 .

[0088]

[0089] Table 2

[0090] Example 2

[0091] The following reference Figure 2 and Figure 4 An optical component according to Example 2 of the present application is described.

[0092] like Figure 4As shown, the optical assembly may include a lens barrel P0 and an optical element group and a spacer group placed in the lens barrel P0. The optical element group may include a linear polarization element LP, a first lens E1, a reflective polarization element RP, a second lens E2, a third lens E3, a quarter wave plate QWP, a fourth lens E4 and a partial reflection layer BS arranged in sequence from the first side to the second side along the optical axis. A stop STO may also be provided between the first side and the linear polarization element LP. The spacer group may also include a first spacer P1, a second spacer P2 and a third spacer P3. In the present embodiment, the first side refers to the human eye side, and the second side refers to the display screen side. The first side of each element (the first lens E1, the second lens E2, the third lens E3, the fourth lens E4) is referred to as the near human eye side, and the second side is referred to as the near screen side.

[0093] The structure of the optical element group of this embodiment is the same as that of the optical element group of embodiment 1, that is, the basic parameter table of the optical assembly of this embodiment is the same as Table 1, and the coefficient table of the aspheric surface or thin Fresnel surface is the same as Table 2. The difference between this embodiment and embodiment 1 is that the structure and size of the lens barrel P0, the first spacer P1, the second spacer P2, and the third spacer P3 are different. For example, the parameters such as D1s, d2s, d2m, D2s, D2m, d3s, d3m, D3s, D3m, CP1, CP2, CP3, EP01, EP12, EP23 and L are different.

[0094] Figure 5A The axial chromatic aberration curves of the optical components of Examples 1 and 2 are shown, which indicate the deviation of the focusing point of light rays of different wavelengths after passing through the optical components. Figure 5B The astigmatism curves of the optical components of Examples 1 and 2 are shown, which represent the meridional image curvature and sagittal image curvature corresponding to different half field angles. Figure 5C The distortion curves of the optical components of Examples 1 and 2 are shown, which represent the distortion values ​​corresponding to different half-viewing angles. FIG. 5A to FIG. 5C It can be seen that the optical components provided in Examples 1 and 2 can achieve good imaging quality.

[0095] Example 3

[0096] The following reference Figure 6 and Figure 7 An optical component according to Example 3 of the present application is described.

[0097] like Figure 7As shown, the optical assembly may include a lens barrel P0 and an optical element group and a spacer group placed in the lens barrel P0. The optical element group may include a linear polarization element LP, a first lens E1, a reflective polarization element RP, a quarter wave plate QWP, a second lens E2, a third lens E3, a fourth lens E4 and a partial reflection layer BS arranged in sequence from the first side to the second side along the optical axis. A stop STO may also be provided between the first side and the linear polarization element LP. The spacer group may also include a first spacer P1, a second spacer P2 and a third spacer P3. In the present embodiment, the first side refers to the human eye side, and the second side refers to the display screen side. The first side of each element (the first lens E1, the second lens E2, the third lens E3, the fourth lens E4) is referred to as the near human eye side, and the second side is referred to as the near screen side.

[0098] The side S1 of the first lens E1 near the human eye is a plane, and the side S2 near the screen is a plane. The second lens E2 has positive focal power, and its side S3 near the human eye is a concave surface, and the side S4 near the screen is a convex surface. The third lens E3 has negative focal power, and its side S5 near the human eye is a concave surface, and the side S6 near the screen is a convex surface. The fourth lens E4 has positive focal power, and its side S7 near the human eye is a convex surface, and the side S8 near the screen is a convex surface. The linear polarization element LP is attached to the side S1 near the human eye of the first lens E1. The reflective polarizing element RP and the quarter-wave plate QWP are bonded and attached together to the side S3 near the human eye of the second lens E2. The partial reflection layer BS is attached to the side S8 near the screen of the fourth lens E4.

[0099] In this example, the second side of the optical component may be provided with an image surface S9 (not shown), and the image surface S9 may be provided with a display screen, for example. Figure 6 As shown, the image light from the image surface S9 passes through the fourth lens E4, the third lens E3, the second lens E2, the quarter-wave plate QWP in sequence and reaches the reflective polarizer RP located on the side of the second lens E2 near the human eye, and then undergoes a first reflection at the reflective polarizer RP. The light reflected for the first time passes through the quarter-wave plate QWP, the second lens E2, the third lens E3, the fourth lens E4 and reaches the partial reflective layer BS located on the side of the fourth lens E4 near the screen, and then undergoes a second reflection at the partial reflective layer BS. The light reflected for the second time passes through the fourth lens E4, the third lens E3, the second lens E2, the quarter-wave plate QWP, the reflective polarizer RP, the first lens E1, the linear polarizer LP to the aperture STO in sequence and is finally projected into the user's eyes. For example, the light of the optical component after two reflections is finally projected into the user's eyes.

[0100] Table 3 shows the basic parameters of the optical components of Example 3, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm). The image light from the image surface S9 passes through the components in the order of sequence number 25 to sequence number 1 and is finally projected into the human eye.

[0101]

[0102]

[0103] Table 3

[0104] In this embodiment, the effective focal length f2 of the second lens is 173.55 mm, the effective focal length f3 of the third lens is -100.14 mm, and the effective focal length f4 of the fourth lens is 62.95 mm.

[0105] In this embodiment, the side surface S3 near the human eye of the second lens E2 and the side surface S8 near the screen of the fourth lens E4 are all aspherical surfaces, and the side surface S4 near the screen of the second lens E2, the side surface S5 and the side surface S6 near the human eye of the third lens E3, and the side surface S7 near the human eye of the fourth lens E4 are all thin Fresnel surfaces. Table 4 shows the cone coefficient k and the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, A50, A51, A52, A53, A54, A55, A56, A57, A58, A59, A6 10 , A 12 and A 14 .

[0106]

[0107] Table 4

[0108] Example 4

[0109] The following reference Figure 6 and Figure 8 An optical component according to Example 4 of the present application is described.

[0110] like Figure 8As shown, the optical assembly may include a lens barrel P0 and an optical element group and a spacer group placed in the lens barrel P0. The optical element group may include a linear polarization element LP, a first lens E1, a reflective polarization element RP, a quarter wave plate QWP, a second lens E2, a third lens E3, a fourth lens E4 and a partial reflection layer BS arranged in sequence from the first side to the second side along the optical axis. A stop STO may also be provided between the first side and the linear polarization element LP. The spacer group may also include a first spacer P1, a second spacer P2 and a third spacer P3. In the present embodiment, the first side refers to the human eye side, and the second side refers to the display screen side. The first side of each element (the first lens E1, the second lens E2, the third lens E3, the fourth lens E4) is referred to as the near human eye side, and the second side is referred to as the near screen side.

[0111] The structure of the optical element group of this embodiment is the same as that of the optical element group of embodiment 3, that is, the basic parameter table of the optical assembly of this embodiment is the same as that of table 3, and the coefficient table of the aspheric surface or thin Fresnel surface is the same as that of table 4. The difference between this embodiment and embodiment 3 is that the structure dimensions of the lens barrel P0, the first spacer P1, the second spacer P2, and the third spacer P3 are different. For example, the parameters such as D1s, d2s, d2m, D2s, D2m, d3s, d3m, D3s, D3m, CP1, CP2, CP3, EP01, EP12, EP23, and L are different.

[0112] Fig.9A The axial chromatic aberration curves of the optical components of Examples 3 and 4 are shown, which indicate the deviation of the focusing point of light of different wavelengths after passing through the optical components. Fig. 9B The astigmatism curves of the optical components of Examples 3 and 4 are shown, which represent the meridional image plane curvature and sagittal image plane curvature corresponding to different half field angles. Fig. 9C The distortion curves of the optical components of Examples 3 and 4 are shown, which represent the distortion values ​​corresponding to different half-viewing angles. 9A to 9C It can be seen that the optical components provided in Examples 3 and 4 can achieve good imaging quality.

[0113] Example 5

[0114] The following reference Fig.10 and Fig.11 An optical component according to Example 5 of the present application is described.

[0115] like Fig.11As shown, the optical assembly may include a lens barrel P0 and an optical element group and a spacer group placed in the lens barrel P0. The optical element group may include a linear polarization element LP, a first lens E1, a reflective polarization element RP, a quarter wave plate QWP, a second lens E2, a third lens E3, a fourth lens E4 and a partial reflection layer BS arranged in sequence from the first side to the second side along the optical axis. A stop STO may also be provided between the first side and the linear polarization element LP. The spacer group may also include a first spacer P1, a second spacer P2 and a third spacer P3. In the present embodiment, the first side refers to the human eye side, and the second side refers to the display screen side. The first side of each element (the first lens E1, the second lens E2, the third lens E3, the fourth lens E4) is referred to as the near human eye side, and the second side is referred to as the near screen side.

[0116] The side S1 of the first lens E1 near the human eye is a plane, and the side S2 near the screen is a plane. The second lens E2 has positive focal power, and its side S3 near the human eye is a convex surface, and the side S4 near the screen is a convex surface. The third lens E3 has negative focal power, and its side S5 near the human eye is a concave surface, and the side S6 near the screen is a convex surface. The fourth lens E4 has positive focal power, and its side S7 near the human eye is a convex surface, and the side S8 near the screen is a convex surface. The linear polarization element LP is attached to the side S1 near the human eye of the first lens E1. The reflective polarizing element RP and the quarter-wave plate QWP are bonded and attached together to the side S3 near the human eye of the second lens E2. The partial reflection layer BS is attached to the side S8 near the screen of the fourth lens E4.

[0117] In this example, the second side of the optical component may be provided with an image surface S9 (not shown), and the image surface S9 may be provided with a display screen, for example. Fig.10 As shown, the image light from the image surface S9 passes through the fourth lens E4, the third lens E3, the second lens E2, the quarter-wave plate QWP in sequence and reaches the reflective polarizer RP located on the side of the second lens E2 near the human eye, and then undergoes a first reflection at the reflective polarizer RP. The light reflected for the first time passes through the quarter-wave plate QWP, the second lens E2, the third lens E3, the fourth lens E4 and reaches the partial reflective layer BS located on the side of the fourth lens E4 near the screen, and then undergoes a second reflection at the partial reflective layer BS. The light reflected for the second time passes through the fourth lens E4, the third lens E3, the second lens E2, the quarter-wave plate QWP, the reflective polarizer RP, the first lens E1, the linear polarizer LP to the aperture STO in sequence and is finally projected into the user's eyes. For example, the light of the optical component after two reflections is finally projected into the user's eyes.

[0118] Table 5 shows the basic parameters of the optical components of Example 5, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm). The image light from the image surface S9 passes through the components in the order of sequence number 25 to sequence number 1 and is finally projected into the human eye.

[0119]

[0120] Table 5

[0121] In this embodiment, the effective focal length f2 of the second lens is 84.91 mm, the effective focal length f3 of the third lens is -135.94 mm, and the effective focal length f4 of the fourth lens is 77.79 mm.

[0122] In this embodiment, the side surface S3 near the human eye of the second lens E2, the side surface S7 near the human eye and the side surface S8 near the screen of the fourth lens E4 are all aspherical surfaces, and the side surface S4 near the screen of the second lens E2, the side surface S5 near the human eye and the side surface S6 near the screen of the third lens E3 are all thin Fresnel surfaces. Table 6 shows the cone coefficient k and the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, A50, A51, A52, A53, A54, A55, A56, A57, A58, A59, A6 10 , A 12 and A 14 .

[0123]

[0124] Table 6

[0125] Example 6

[0126] The following reference Fig.10 and Fig.12 An optical component according to Example 6 of the present application is described.

[0127] like Fig.12 As shown, the optical assembly may include a lens barrel P0 and an optical element group and a spacer group placed in the lens barrel P0. The optical element group may include a linear polarization element LP, a first lens E1, a reflective polarization element RP, a quarter wave plate QWP, a second lens E2, a third lens E3, a fourth lens E4 and a partial reflection layer BS arranged in sequence from the first side to the second side along the optical axis. A stop STO may also be provided between the first side and the linear polarization element LP. The spacer group may also include a first spacer P1, a second spacer P2 and a third spacer P3. In the present embodiment, the first side refers to the human eye side, and the second side refers to the display screen side. The first side of each element (the first lens E1, the second lens E2, the third lens E3, the fourth lens E4) is referred to as the near human eye side, and the second side is referred to as the near screen side.

[0128] The structure of the optical element group of this embodiment is the same as that of the optical element group of embodiment 5, that is, the basic parameter table of the optical assembly of this embodiment is the same as that of table 5, and the coefficient table of the aspheric surface or thin Fresnel surface is the same as that of table 6. The difference between this embodiment and embodiment 5 is that the structure dimensions of the lens barrel P0, the first spacer P1, the second spacer P2, and the third spacer P3 are different. For example, the parameters such as D1s, d2s, d2m, D2s, D2m, d3s, d3m, D3s, D3m, CP1, CP2, CP3, EP01, EP12, EP23, and L are different.

[0129] Fig.13A The axial chromatic aberration curves of the optical components of Examples 5 and 6 are shown, which indicate the deviation of the focusing point of light rays of different wavelengths after passing through the optical components. Fig. 13B The astigmatism curves of the optical components of Examples 5 and 6 are shown, which represent the meridional image plane curvature and sagittal image plane curvature corresponding to different half field angles. Fig. 13C The distortion curves of the optical components of Examples 5 and 6 are shown, which represent the distortion values ​​corresponding to different half-viewing angles. FIG. 13A to FIG. 13C It can be seen that the optical components provided in Examples 5 and 6 can achieve good imaging quality.

[0130] Table 7 gives some basic parameters of the lens barrel P0, the first spacer P1, the second spacer P2, and the third spacer P3 of Examples 1 to 6, such as D1s, d2s, d2m, D2s, D2m, d3s, d3m, D3s, D3m, CP1, CP2, CP3, EP01, EP12, EP23, and L. Some of the basic parameters listed in Table 7 are as follows: Figure 1 The units of the basic parameters listed in Table 7 are all millimeters (mm).

[0131]

[0132]

[0133] Table 7

[0134] In summary, Table 8 shows the values ​​of the conditional expressions of each of Examples 1 to 6.

[0135] Conditional / Example 1 2 3 4 5 6 (EP01+CP1) / CT1 6.16 5.46 4.51 4.51 6.26 6.26 f2 / (D2s+D1s) 1.40 1.40 2.10 2.10 1.01 1.01 R4×N2 / d2s -2.33 -2.33 -1.52 -1.52 -2.22 -2.22 CT2×V2 / (CP1+CP2) 65.52 65.52 49.99 49.99 36.05 36.05 (CT2+T12) / EP12 1.53 1.53 1.07 1.07 1.77 1.77 R5 / (D2m-d2m) -28.22 -28.22 -22.27 -22.27 -32.55 -32.55 R6 / d3s+R6 / D3s -2.49 -2.39 -3.20 -3.20 -3.28 -3.31 CT3×V3 / (CP2+CP3) 10.93 10.93 11.10 11.10 4.00 4.00 f3 / d3s -3.80 -3.85 -2.55 -2.55 -3.32 -3.32 (CT3+T23) / EP23 1.30 1.30 1.85 1.85 2.62 2.62 L / (CT4+T34) 2.32 2.32 2.17 1.75 2.80 2.80 f4 / D3m 1.63 1.50 1.48 1.48 1.81 1.81 R8 / (D3m-d3m) -39.99 -10.04 -12.31 -12.31 -34.71 -34.71

[0136] Table 8

[0137] The present application also provides an optical device, which may be an independent projection device such as a projector, or a projection module integrated in a mobile electronic device such as a virtual reality device. The optical device is equipped with the optical components described above.

[0138] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the utility model involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in the present application (but not limited to) by each other.

Claims

1. An optical component, characterized in that It comprises a lens barrel and an optical element group and a spacer group placed in the lens barrel; The optical element group includes, in sequence from the first side to the second side along the optical axis: A first lens, wherein the first side surface is a plane and the second side surface is a plane; a second lens having positive optical power, wherein the second side surface of the second lens is convex; a third lens having negative optical power, wherein the first side surface is concave and the second side surface is convex; a fourth lens having positive power, wherein the first side surface is convex and the second side surface is convex; The optical element group further includes a linear polarization element, a reflective polarization element, a quarter wave plate and a partial reflection layer; at least one surface of at least one lens among the first lens to the fourth lens is a thin Fresnel surface; The spacer group includes a first spacer disposed on the second side of the first lens and in contact with the second side of the first lens, and a second spacer disposed on the second side of the second lens and in contact with the second side of the second lens; The interval EP01 between the first side end surface of the lens barrel and the first spacer along the optical axis, the maximum thickness CP1 of the first spacer and the center thickness CT1 of the first lens on the optical axis satisfy: 4.5<(EP01+CP1) / CT1<6.3; The effective focal length f2 of the second lens, the outer diameter D1s of the first side surface of the first spacer, and the outer diameter D2s of the first side surface of the second spacer satisfy: 1.0 <f2 / (D2s+D1s)<2.2。 2. The optical component according to claim 1, characterized in that The curvature radius R4 of the second side surface of the second lens, the refractive index N2 of the second lens, and the inner diameter d2s of the first side surface of the second spacer satisfy: -2.5 <R4×N2 / d2s<-1.5。 3. The optical component according to claim 1, characterized in that The center thickness CT2 of the second lens on the optical axis, the Abbe number V2 of the second lens, the maximum thickness CP1 of the first spacer and the maximum thickness CP2 of the second spacer satisfy: 36.0 <CT2×V2 / (CP1+CP2)<66.0。 4. The optical component according to claim 1, characterized in that The center thickness CT2 of the second lens on the optical axis, the on-axis distance T12 from the second side surface of the first lens to the first side surface of the second lens, and the interval EP12 between the first spacer and the second spacer along the optical axis satisfy: 1.0<(CT2+T12) / EP12<1.

8.

5. The optical component according to claim 1, characterized in that The curvature radius R5 of the first side surface of the third lens, the inner diameter d2m of the second side surface of the second spacer, and the outer diameter D2m of the second side surface of the second spacer satisfy: -33.0 <R5 / (D2m-d2m)<-22.0。 6. The optical component according to any one of claims 1 to 5, characterized in that: The spacer set further includes a third spacer disposed on the second side surface of the third lens and in contact with the second side surface of the third lens. The curvature radius R6 of the second side surface of the third lens, the inner diameter d3s of the first side surface of the third spacer, and the outer diameter D3s of the second side surface of the third spacer satisfy: -3.5 <R6 / d3s+R6 / D3s<-2.0。 7. The optical component according to any one of claims 1 to 5, characterized in that: The spacer set further includes a third spacer disposed on the second side surface of the third lens and in contact with the second side surface of the third lens. The center thickness CT3 of the third lens on the optical axis, the Abbe number V3 of the third lens, the maximum thickness CP2 of the second spacer and the maximum thickness CP3 of the third spacer satisfy: 4.0≤CT3×V3 / (CP2+CP3)≤11.

1.

8. The optical component according to any one of claims 1 to 5, characterized in that: The spacer set further includes a third spacer disposed on the second side surface of the third lens and in contact with the second side surface of the third lens. The effective focal length f3 of the third lens and the inner diameter d3s of the first side surface of the third spacer satisfy: -4.0 <f3 / d3s<-2.5。 9. The optical component according to any one of claims 1 to 5, characterized in that: The spacer set further includes a third spacer disposed on the second side surface of the third lens and in contact with the second side surface of the third lens. Among them, the center thickness CT3 of the third lens on the optical axis, the on-axis distance T23 from the second side surface of the second lens to the first side surface of the third lens, and the interval EP23 between the second spacer and the third spacer along the optical axis satisfy: 1.2<(CT3+T23) / EP23≤2.

7.

10. The optical component according to any one of claims 1 to 5, characterized in that: The length L of the lens barrel in the direction of the optical axis, the center thickness CT4 of the fourth lens on the optical axis, and the axial distance T34 from the second side surface of the third lens to the first side surface of the fourth lens satisfy: 1.5 <L / (CT4+T34)<3.0。 11. The optical component according to any one of claims 1 to 5, characterized in that: The spacer set further includes a third spacer disposed on the second side surface of the third lens and in contact with the second side surface of the third lens. The effective focal length f4 of the fourth lens and the outer diameter D3m of the second side surface of the third spacer satisfy: 1.4 <f4 / D3m<1.9。 12. The optical component according to any one of claims 1 to 5, characterized in that: The spacer set further includes a third spacer disposed on the second side surface of the third lens and in contact with the second side surface of the third lens. The curvature radius R8 of the second side surface of the fourth lens, the inner diameter d3m of the second side surface of the third spacer, and the outer diameter D3m of the second side surface of the third spacer satisfy: -40.0≤R8 / (D3m-d3m)<-10.0.

Images