Optical system and optical apparatus comprising the same

Abstract

The application discloses an optical system and an optical device comprising the same. The optical system comprises a lens group, which comprises, in order from a first side to a second side along an optical axis, a first lens group, a second lens, and a third lens. The first lens group has positive refractive power and comprises, in order from the first side to the second side, a reflective polarizing element, a quarter-wave plate, and a first lens. The optical system further comprises at least one abutting element, which comprises a second abutting element arranged on and in contact with a second side surface of the second lens, and a lens barrel for accommodating the lens group and the at least one abutting element. The optical system further comprises a partial reflection layer. A dispersion coefficient VRP of the reflective polarizing element, an effective focal length F1 of the first lens group, and an outer diameter D0s of a first side end surface of the lens barrel satisfy 20<VRP×F1 / D0s<210. An effective focal length f2 of the second lens, an effective focal length f3 of the third lens, an inner diameter d2s of a first side surface of the second abutting element, and an inner diameter d0m of a second side end surface of the lens barrel satisfy 0<|f2+f3| / (d2s+d0m)<5.

Description

TECHNICAL FIELD

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

[0002] The catadioptric optical system scheme realizes the folding of light in different optical elements by pasting and coating films on lenses, and finally achieves the purpose of shortening the length of the entire optical system. Compared with the previous aspherical lens and Fresnel lens schemes, the catadioptric optical system scheme has a better development prospect.

[0003] The catadioptric optical system commonly used in the market at present emphasizes the imaging quality of the central field of view, especially the on-axis position chromatic aberration and spherical aberration, but ignores the problem of poor imaging quality of the outer field of view. At the same time, the commonly used two-piece catadioptric optical system has less space for optimization. Therefore, how to improve the user experience while ensuring that the length of the optical device will not become longer due to the increase in the number of lenses has become a development trend of catadioptric optical devices. How to overcome the problem of imaging quality of the outer field of view under the condition of ensuring the stability of the assembly of the catadioptric optical system and the controllability of stray light has become one of the current research hotspots. SUMMARY

[0004] The first aspect of the present application provides an optical system, comprising: a lens group comprising, in order from a first side to a second side along an optical axis: a first lens group, a second lens, and a third lens, wherein the first lens group has a positive focal power, comprises, in order from the first side to the second side: a reflective polarizing element, a quarter-wave plate, and a first lens, and the second side of the reflective polarizing element is in abutment with the first side of the quarter-wave plate, and the second side of the quarter-wave plate is in abutment with the first side of the first lens; at least one abutting element comprising a second abutting element disposed on and in contact with the second side of the second lens; and a lens barrel for accommodating the lens group and the at least one abutting element; wherein the optical system further comprises a partial reflection layer disposed on the second side of the first lens or the first side of the second lens; a dispersion coefficient VRP of the reflective polarizing element, an effective focal length F1 of the first lens group, and an outer diameter D0s of a first side end face of the lens barrel satisfy: 20<VRP×F1 / D0s<210; and an effective focal length f2 of the second lens, an effective focal length f3 of the third lens, an inner diameter d2s of a first side face of the second abutting element, and an inner diameter d0m of a second side end face of the lens barrel satisfy: 0<|f2+f3| / (d2s+d0m)<5.

[0005] In one embodiment, the inner diameter d0m of the second side end face of the lens barrel, the inner diameter d0s of the first side end face of the lens barrel, and the curvature radius R1 of the first side of the first lens satisfy: -5.1<(d0m+d0s) / R1<-1.

[0006] In one embodiment, the first side surface of the first lens is a concave surface, the second side surface of the second lens is a convex surface, and a radius of curvature R1 of the first side surface of the first lens and a radius of curvature R4 of the second side surface of the second lens satisfy: 1.5 x R1 > R4.

[0007] In one embodiment, the radius of curvature of the first side surface and the second side surface of the reflective polarizing element are the same, and a radius of curvature RRP of the second side surface of the reflective polarizing element, a radius of curvature R4 of the second side surface of the second lens, an inner diameter d2m of the second side surface of the second abutting element, and an inner diameter d0s of the first side end surface of the lens barrel satisfy: -10 < (RRP - R4) / (d2m + d0s) < 0.

[0008] In one embodiment, an outer diameter D0m of the second side end surface of the lens barrel, a maximum height L of the lens barrel in the optical axis direction, an effective focal length f of the optical system, and a sum ΣCT of the center thicknesses of the first lens, the second lens, and the third lens in the optical axis direction satisfy: 2 < D0m / L x f / ΣCT < 4.

[0009] In one embodiment, an Abbe number V2 of the second lens, an Abbe number V3 of the third lens, an Abbe number V1 of the first lens, an inner diameter d2s of the first side surface of the second abutting element, an inner diameter d2m of the second side surface of the second abutting element, and an outer diameter D0s of the first side end surface of the lens barrel satisfy: 0 < (V2 + V3) / V1 x (d2s + d2m) / D0s < 4.

[0010] In one embodiment, an outer diameter D2s of the first side surface of the second abutting element, a maximum field angle FOV of the optical system, and an on-axis distance TrRPrBS from the first side surface of the reflective polarizing element to the surface of the lens where the partial reflection layer is located satisfy: 6 < D2s x tan(FOV / 2) / TrRPrBS < 20.

[0011] In one embodiment, a maximum thickness CP2 of the second abutting element in the optical axis direction, an F-number Fno of the optical system, and an air interval T12 of the first lens to the second lens in the optical axis direction satisfy: 6 < CP2 x Fno / T12 < 100.

[0012] In one embodiment, a refractive index NRP of the reflective polarizing element, a refractive index NQWP of the quarter-wave plate, an effective focal length F1 of the first lens group, and an outer diameter D0s of the first side end surface of the lens barrel satisfy: 1 < (NRP + NQWP) x F1 / D0s < 11.

[0013] In one embodiment, the maximum height L of the lens barrel in the direction of the optical axis, the F-number Fno of the optical system, the outer diameter D0s of the first side end surface of the lens barrel, and the outer diameter D0m of the second side end surface of the lens barrel satisfy: 20 < LxFno / |D0s-D0m| < 110.

[0014] In one embodiment, the distance TD of the first side surface of the first lens to the second side surface of the third lens in the direction of the optical axis, the center thickness CTRP of the reflective polarizing element in the direction of the optical axis, the center thickness CTQWP of the quarter-wave plate in the direction of the optical axis, the effective focal length f of the optical system, the maximum field angle FOV of the optical system, and the outer diameter D0m of the second side end surface of the lens barrel satisfy: 4 < (TD+CTRP+CTQWP) / (fxtan(FOV / 2)-D0m / 2) < 35.

[0015] In one embodiment, the radii of curvature of the first side surface of the first lens and the second side surface of the first lens are the same; the distance SAG11 of the intersection of the first side surface of the first lens in the direction of the optical axis to the maximum effective radius vertex of the first side surface of the first lens, the radius of curvature RQWP of the second side surface of the quarter-wave plate, the outer diameter D0s of the first side end surface of the lens barrel, and the center thickness CT1 of the first lens in the direction of the optical axis satisfy: 0 < SAG11 / RQWPxD0s / CT1 < 4.

[0016] In one embodiment, the at least one abutting element further includes a first abutting element disposed on the second side surface of the first lens and in contact with the second side surface of the first lens; and the outer diameter D0m of the second side end surface of the lens barrel, the inner diameter d1m of the second side surface of the first abutting element, the center thickness CT2 of the second lens in the direction of the optical axis, the air interval T23 of the second lens to the third lens in the direction of the optical axis, and the center thickness CT3 of the third lens in the direction of the optical axis satisfy: 0 < (D0m-d1m) / (CT2+T23+CT3) < 2.

[0017] In one embodiment, the radius of curvature R1 of the first side surface of the first lens, the distance EP01 of the first side end surface of the lens barrel and the first side surface of the first abutting element in the direction of the optical axis, the radius of curvature R4 of the second side surface of the second lens, and the distance EP12 of the second side surface of the first abutting element and the first side surface of the second abutting element in the direction of the optical axis satisfy: -500 < R1 / EP01+R4 / EP12 < -20.

[0018] The second aspect of the present application also provides an optical system, comprising: a lens group, sequentially comprising: a first lens group, a second lens, and a third lens along an optical axis from a first side to a second side, wherein the first lens group sequentially comprises: a reflective polarizing element, a quarter-wave plate, and a first lens from the first side to the second side, and a second side of the reflective polarizing element is attached to a first side of the quarter-wave plate, and a second side of the quarter-wave plate is attached to a first side of the first lens; at least one abutting element, comprising a second abutting element arranged on a second side of the second lens and in contact with the second side of the second lens; a lens barrel for accommodating the lens group and the at least one abutting element; wherein the first side of the first lens is a concave surface, and the second side is a convex surface; at least one of the second lens and the third lens is a biconvex lens; the sign of the focal power of the second lens and the sign of the focal power of the third lens are opposite in sign; and the optical system satisfies: -2 < f2 / f3 < 0 and -4 < (f2+f3) / (d2s+d2m) < 0.5, wherein f2 is the effective focal length of the third lens, f3 is the effective focal length of the third lens, d2s is the inner diameter of the first side of the second abutting element, and d2m is the inner diameter of the second side of the second abutting element.

[0019] The third aspect of the present application also provides an optical device comprising the optical system provided by at least one of the various embodiments described above.

[0020] The optical system provided by the present application is a three-piece catadioptric optical system, which has good projection quality, small total length, and good processability by reasonably arranging the structures of the three lenses, the reflective polarizing element, the quarter-wave plate, the partial reflection layer, the abutting element, and the lens barrel, and satisfying 20 < VRP x F1 / D0s < 210 and 0 < |f2+f3| / (d2s+d0m) < 5. Generally, a three-piece catadioptric optical system has the problem of poor imaging quality in the outer field of view. By controlling the dispersion coefficient of the reflective polarizing element and the effective focal length of the first lens group, and the outer diameter of the first side end of the lens barrel, the inner diameter of the first side of the second abutting element, and the inner diameter of the second side end of the lens barrel, it is beneficial to reduce the stray light between the first lens and the second lens, constrain the flocculent stray light and the feather-like stray light, constrain the chromatic aberration of the system, especially the chromatic aberration of the optical system within a field of view of 53°, and also reduce the spherical aberration, thereby improving the imaging effect of the optical system on the axis. BRIEF DESCRIPTION OF DRAWINGS

[0021] Other features, objects, and advantages of the present application will become more apparent from the following detailed description of the non-limiting embodiments, in conjunction with the accompanying drawings. In the drawings:

[0022] Figure 1A structural arrangement diagram and a schematic diagram of partial parameters of an optical system according to the present application are shown.

[0023] Figures 2A to 2C A structural schematic diagram of an optical system according to Embodiment 1 of the present application is shown.

[0024] Figures 3A to 3C An on-axis chromatic aberration curve, an astigmatism curve and a distortion curve of the optical system according to Embodiment 1 of the present application are shown respectively.

[0025] Figures 4A to 4C A structural schematic diagram of an optical system according to Embodiment 2 of the present application is shown.

[0026] Figures 5A to 5C An on-axis chromatic aberration curve, an astigmatism curve and a distortion curve of the optical system according to Embodiment 2 of the present application are shown respectively.

[0027] Figures 6A to 6C A structural schematic diagram of an optical system according to Embodiment 3 of the present application is shown.

[0028] Figures 7A to 7C An on-axis chromatic aberration curve, an astigmatism curve and a distortion curve of the optical system according to Embodiment 3 of the present application are shown respectively. DETAILED DESCRIPTION

[0029] For a better understanding of the present application, various aspects of the present application will be described in more detail below with reference to the accompanying drawings. It is to be noted that the detailed description is only a description of exemplary embodiments of the present application and does not limit the scope of the present application in any way. Throughout the specification, like reference numerals refer to like elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0030] It should be noted that the expressions first, second, etc. in the present specification are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, the first lens discussed below can also be referred to as the second lens, and the second lens can also be referred to as the first lens without departing from the teachings of the present application.

[0031] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shape of the spherical surface or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical surface or aspherical surface is not limited to the shape of the spherical surface or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn strictly to scale.

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

[0033] It should also be understood that the words "comprise," "comprising," "include," "including," and / or "has," "having," when used in this specification, specify the presence of stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or groups thereof. Furthermore, when describing the application, the use of "or" means "and / or" unless otherwise stated. In addition, the use of "a" or "an" means "one or more" unless otherwise stated. Also, the use of "an exemplary embodiment" or "one exemplary embodiment" means that a particular feature, structure, or result can be included in a given embodiment. Moreover, the phrases "an exemplary embodiment" or "one exemplary embodiment" indicate that a particular feature, structure, or result can be included in at least one embodiment. Thus, the appearances of the phrases "an exemplary embodiment" or "one exemplary embodiment" in various places throughout this specification do not necessarily refer to the same embodiment. Furthermore, the terms "comprise," "comprising," "include," "including," and / or "has," "having" along with their conjugates merely mean that an article, feature, component, and / or element can possibly possess the stated characteristics, but does not preclude the presence or addition of one or more other features, elements, components, and / or groups thereof.

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

[0035] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0036] The features, principles, and other aspects of the present application will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0037] An optical system according to an exemplary embodiment of the present application can include three lenses having optical power, which are a first lens, a second lens, and a third lens. The three lenses are arranged in order along an optical axis from a first side to a second side. Any two adjacent lenses among the first lens to the third lens can have a separation distance.

[0038] The optical system according to the exemplary embodiments of the present application can include at least one abutting element. For example, the at least one abutting element can include a second abutting element disposed on the second side of the second lens and in contact with the second side of the second lens. For example, the at least one abutting element can also include a first abutting element disposed on the second side of the first lens and in contact with the second side of the first lens. It should be understood that the number of abutting elements is not specifically limited in the present application, and any number of abutting elements can be included between any two lenses, and any number of abutting elements can be included in the entire optical system. The abutting elements help the optical system to intercept the excess catadioptric optical path, and reduce the generation of stray light and ghost. The abutting elements and the lens barrel increase the auxiliary abutment, which is beneficial to improve the poor assembly stability and low performance yield caused by large step difference between lenses. By reasonably setting the number, thickness, inner diameter and outer diameter of the abutting elements, the assembly of the optical system is improved, the stray light is blocked, and the projection quality of the optical system is improved.

[0039] The optical system according to the exemplary embodiments of the present application can include a lens barrel accommodating the lens group and the at least one abutting element. For example, the lens barrel can be a one-piece lens barrel.

[0040] The optical system according to the exemplary embodiments of the present application includes a lens group, at least one abutting element and a lens barrel. The lens group includes, in order from the first side to the second side along the optical axis, a first lens group, a second lens and a third lens. The first lens group has a positive focal power and includes, in order from the first side to the second side, a reflective polarizing element, a quarter-wave plate and a first lens. The second side of the reflective polarizing element is in contact with the first side of the quarter-wave plate, and the second side of the quarter-wave plate is in contact with the first side of the first lens.

[0041] Figure 1 The structural arrangement of the optical system according to the present application and the schematic diagram of some parameters are shown. It should be understood by those skilled in the art that some parameters of the lens commonly used in the art, such as the center thickness CT1 of the first lens on the optical axis, are not shown in the Figure 1 Figure 1 Only some parameters of the lens barrel and the abutting element of the optical system according to the present application are shown for better understanding of the present application. For example, Figure 1 ​As shown, L represents the maximum height of the lens barrel in the optical axis direction, EP01 represents the distance between the first side end surface of the lens barrel and the first side surface of the first abutting element in the optical axis direction, EP12 represents the distance between the second side surface of the first abutting element and the first side surface of the second abutting element in the optical axis direction, CP2 represents the maximum thickness of the second abutting element in the optical axis direction, D0s represents the outer diameter of the first side end surface of the lens barrel, d0s represents the inner diameter of the first side end surface of the lens barrel, d1m represents the inner diameter of the second side surface of the first abutting element, d2s represents the inner diameter of the first side surface of the second abutting element, d2m represents the inner diameter of the second side surface of the second abutting element, D2s represents the outer diameter of the first side surface of the second abutting element, d0m represents the inner diameter of the second side end surface of the lens barrel, and D0m represents the outer diameter of the second side end surface of the lens barrel.

[0042] In an example embodiment, the optical system further comprises a display disposed on the second side of the third lens, and the optical system can be applied to, for example, a VR device, the first side can be, for example, the side of the human eye, and the second side can be, for example, the side of the display. The image light on the display screen passes through the third lens, the second lens, the first lens, the quarter wave plate, and the reflective polarizing element multiple times for refraction and reflection, and is finally projected to the eyes of the user.

[0043] In an example embodiment, the optical system further comprises a partial reflection layer disposed on the second side of the first lens or the first side of the second lens. The partial reflection layer has a semi-transparent and semi-reflective function. In some embodiments, as shown in Figure 2A and Figure 4A As shown, the second side of the first lens is provided with a partial reflection layer, and the light emitted by the display screen sequentially passes through the third lens, the second lens, the first lens, the quarter wave plate QWP, and reaches the reflective polarizing element RP, is reflected at the reflective polarizing element RP and passes through the quarter wave plate QWP and the first lens again, and then the light beam is reflected again at the partial reflection layer on the second side of the first lens and sequentially passes through the first lens, the quarter wave plate QWP, the reflective polarizing element RP, passes through the light stop STO and is finally emitted towards the side of the human eye. In other embodiments, as shown in Figure 6A As shown, the second side of the first lens is provided with a partial reflection layer, and the light emitted by the display screen sequentially passes through the third lens, the second lens, the first lens, the quarter wave plate QWP, and reaches the reflective polarizing element RP, is reflected at the reflective polarizing element RP and passes through the quarter wave plate QWP and the first lens again, and then the light beam is reflected again at the partial reflection layer on the second side of the first lens and sequentially passes through the first lens, the quarter wave plate QWP, the reflective polarizing element RP, passes through the light stop STO and is finally emitted towards the side of the human eye. In other embodiments, as shown in

[0044] In the example embodiment, the reflective polarizing element and the quarter-wave plate are combined, and the required structure is obtained by one attaching process operation instead of two attaching processes, so that the angle position error caused by the attaching is reduced, and the imaging quality is improved.

[0045] The optical system according to the example embodiment of the present application can reflect light of a certain polarization direction and transmit light orthogonal to the polarization direction by arranging the reflective polarizing element, change the polarization state of the light by arranging the quarter-wave plate, and realize reflection and transmission by the partial reflection layer on the second side of the first lens or the first side of the second lens, so that the optical path of the system is folded and reflected, and the length of the optical system is shortened.

[0046] In the example embodiment, the optical system of the present application can satisfy 20<VRP×F1 / D0s<210, where VRP is the dispersion coefficient of the reflective polarizing element, F1 is the effective focal length of the first lens group, and D0s is the outer diameter of the first side end surface of the lens barrel. Satisfying 20<VRP×F1 / D0s<210 can control the dispersion coefficient of the reflective polarizing element and the effective focal length of the first lens group, so as to constrain the chromatic aberration of the system, and control the outer diameter of the first side end surface of the lens barrel, so as to limit the outer diameter of the lens barrel to a proper size.

[0047] In the example embodiment, the optical system of the present application can satisfy 0<|f2+f3| / (d2s+d0m)<5, where f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, d2s is the inner diameter of the first side of the second bearing element, and d0m is the inner diameter of the second side end surface of the lens barrel. Satisfying 0<|f2+f3| / (d2s+d0m)<5 can control the effective focal lengths of the second lens and the third lens within a certain range, so as to ensure good imaging effect of the system on the optical axis; secondly, by controlling the inner diameter of the first side of the second bearing element and the inner diameter of the second side end surface of the lens barrel, the machinability of the second bearing element and the lens barrel is improved on the basis of ensuring the functional effect, and the stray light between the first lens and the second lens is reduced, the flocculent stray light and the feather-like stray light are constrained, the chromatic aberration of the system, especially the chromatic aberration of the optical system within a field of view of 53°, is constrained, the spherical aberration is reduced, and the imaging effect of the optical system on the optical axis is improved.

[0048] In the example embodiment, the optical system of the present application can satisfy -5.1 < (d0m+d0s) / R1 < -1, where d0m is the inner diameter of the second side end face of the lens barrel, d0s is the inner diameter of the first side end face of the lens barrel, and R1 is the curvature radius of the first side face of the first lens. Satisfying -5.1 < (d0m+d0s) / R1 < -1, by limiting the inner diameters of the first side end face and the second side end face of the lens barrel, on the one hand, it is beneficial to control the amount of light and more efficient use of light imaging, on the other hand, it is beneficial to better improve the radiation of excess light, reduce stray light generation as much as possible, and improve imaging clarity; by limiting the curvature radius of the first side face of the first lens, the sizes of the second lens and the third lens can be better arranged.

[0049] In the example embodiment, the first side face of the first lens of the optical system of the present application is a concave surface, and the second side face of the second lens is a convex surface.

[0050] In the example embodiment, the optical system of the present application can satisfy the condition 1.5 x R1 > R4, where R1 is the curvature radius of the first side face of the first lens, and R4 is the curvature radius of the second side face of the second lens. Satisfying 1.5 x R1 > R4, by controlling the relationship between the curvature radius of the first side face of the first lens and the curvature radius of the second side face of the second lens, the shapes of the first lens and the second lens are constrained, so that the two lenses are properly matched, and the stability of the two lens assemblies is promoted.

[0051] In the example embodiment, the curvature radii of the first side face and the second side face of the reflective polarizing element are the same, and the optical system of the present application can satisfy -10 < (RRP1+R4) / (d2m+d0s) < 0, where RRP is the curvature radius of the second side face of the reflective polarizing element, R4 is the curvature radius of the second side face of the second lens, d2m is the inner diameter of the second side face of the second supporting element, and d0s is the inner diameter of the first side end face of the lens barrel. The curvature radii of the first side face and the second side face of the reflective polarizing element are the same, which can reduce the difficulty of attaching the reflective polarizing element to the first lens; satisfying -10 < (RRP1+R4) / (d2m+d0s) < 0, by controlling the curvature radius of the second side face of the reflective polarizing element and the curvature radius of the second side face of the second lens, it is beneficial to reduce the sensitivity of the first lens and the second lens and improve the assembly yield; secondly, limiting the inner diameter of the second side face of the second supporting element and the inner diameter of the first side end face of the lens barrel ensures its processability.

[0052] In the example embodiment, the optical system of the present application can satisfy: 2 < D0m / L x f / ∑CT < 4, where D0m is the outer diameter of the second side end surface of the lens barrel, L is the maximum height of the lens barrel along the optical axis, f is the effective focal length of the optical system, and ∑CT is the sum of the center thicknesses of the first lens, the second lens, and the third lens on the optical axis. Satisfying 2 < D0m / L x f / ∑CT < 4, by controlling the effective focal length of the optical system, the field of view angle of the optical system is effectively constrained so that the system satisfies the characteristics of a large field of view; controlling the outer diameter of the second side end surface of the lens barrel, the maximum height of the lens barrel along the optical axis, and the sum of the center thicknesses of all the lenses indirectly ensures the assembly stability of the lens.

[0053] In the example embodiment, the optical system of the present application can satisfy: 0 < (V2+V3) / V1 x (d2s+d2m) / D0s < 4, where V2 is the Abbe number of the second lens, V3 is the Abbe number of the third lens, V1 is the Abbe number of the first lens, d2s is the inner diameter of the first side surface of the second bearing element, d2m is the inner diameter of the second side surface of the second bearing element, and D0s is the outer diameter of the first side end surface of the lens barrel. Satisfying 0 < (V2+V3) / V1 x (d2s+d2m) / D0s < 4, by controlling the Abbe numbers of the first lens, the second lens, and the third lens, the chromatic aberration of the system is favorably constrained to improve the imaging quality of the optical system; controlling the inner diameters of the first side surface and the second side surface of the second bearing element and the outer diameter of the first side end surface of the lens barrel satisfies the supportability and processability of the second bearing element to the lenses and also ensures that the lens barrel has a suitable wall thickness.

[0054] In the example embodiment, the lens group further includes a partial reflection layer arranged on the second side surface of the first lens or the first side surface of the second lens, and the optical system of the present application can satisfy: 6 < D2s x tan(FOV / 2) / TrRPrBS < 20, where D2s is the outer diameter of the first side surface of the second bearing element, FOV is the maximum field of view angle of the optical system, and TrRPrBS is the axial distance from the first side surface of the reflective polarizing element to the surface of the lens on which the partial reflection layer is arranged. Satisfying 6 < D2s x tan(FOV / 2) / TrRPrBS < 20, by controlling the outer diameter of the first side surface of the second bearing element and the axial distance from the first side surface of the reflective polarizing element to the surface of the lens on which the partial reflection layer is arranged, the size of the entire system is compressed under the condition that the maximum field of view angle of the system is unchanged, achieving the purpose of compact equipment.

[0055] In the example embodiment, the optical system of the present application can satisfy: 6 < CP2 x Fno / T12 < 100, wherein CP2 is the maximum thickness of the second abutting element along the optical axis direction, Fno is the aperture number of the optical system, and T12 is the air spacing of the first lens to the second lens on the optical axis. Satisfying 6 < CP2 x Fno / T12 < 100, by controlling the on-axis spacing of the first lens to the second lens, the maximum thickness of the second abutting element, and the aperture number of the optical system, it is beneficial to indirectly control the focal length of the system under the condition that the entrance pupil diameter is unchanged, so that the system satisfies the characteristics of a large field of view.

[0056] In the example embodiment, the optical system of the present application can satisfy: 1 < (NRP + NQWP) x F1 / D0s < 11, wherein NRP is the refractive index of the reflective polarizing element, NQWP is the refractive index of the quarter-wave plate, F1 is the effective focal length of the first lens group, and D0s is the outer diameter of the first side end surface of the lens barrel. Satisfying 1 < (NRP + NQWP) x F1 / D0s < 11, by controlling the ratio of the refractive indices of the reflective polarizing element and the quarter-wave plate to the effective focal length of the first lens group, the influence of changes in the thickness of the reflective polarizing element and the quarter-wave plate on the system can be effectively reduced; secondly, by controlling the outer diameter of the first side end surface of the lens barrel, it is beneficial to control the lens barrel outer diameter to maintain a suitable size and improve its processability.

[0057] In the example embodiment, the optical system of the present application can satisfy: 20 < L x Fno / |D0s - D0m| < 110, wherein L is the maximum height of the lens barrel along the optical axis direction, Fno is the aperture number of the optical system, D0s is the outer diameter of the first side end surface of the lens barrel, and D0m is the outer diameter of the second side end surface of the lens barrel. Satisfying 20 < L x Fno / |D0s - D0m| < 110, by controlling the aperture number of the optical system, the maximum height of the lens barrel along the optical axis direction, and the outer diameters of the first side end surface and the second side end surface of the lens barrel, on the one hand, the focal length of the system is indirectly controlled, so that the lens satisfies the characteristics of a large field of view, and on the other hand, the processability of the lens barrel can be guaranteed.

[0058] In the exemplary embodiments, the optical system of the present application can satisfy: 4 < (TD + CTRP + CTQWP) / (f x tan(FOV / 2) - Dom / 2) < 35, where TD is the distance from the first side of the first lens to the second side of the third lens on the optical axis, CTRP is the central thickness of the reflective polarizing element along the optical axis, CTQWP is the central thickness of the quarter-wave plate along the optical axis, f is the effective focal length of the optical system, FOV is the maximum field of view angle of the optical system, and Dom is the outer diameter of the second side end surface of the lens barrel. Satisfying 4 < (TD + CTRP + CTQWP) / (f x tan(FOV / 2) - Dom / 2) < 35 controls the image height of the system, limits the size of the screen, and limits the size of the entire optical system by controlling the axial distance from the first side of the first lens to the second side of the third lens, the sum of the central thicknesses of the reflective polarizing element and the quarter-wave plate, the effective focal length of the optical system, the maximum field of view angle of the optical system, and the outer diameter of the second side end surface of the lens barrel.

[0059] In the exemplary embodiments, the radii of curvature of the first side and the second side of the quarter-wave plate are the same, and the optical system of the present application can satisfy: 0 < SAG11 / RQWP x D0s / CT1 < 4, where SAG11 is the distance from the intersection of the first side of the first lens on the optical axis to the maximum effective radius vertex of the first side of the first lens on the optical axis, RQWP is the radius of curvature of the second side of the quarter-wave plate, D0s is the outer diameter of the first side end surface of the lens barrel, and CT1 is the central thickness of the first lens on the optical axis. Satisfying 0 < SAG11 / RQWP x D0s / CT1 < 4 controls the radii of curvature of the first side and the second side of the quarter-wave plate, which is beneficial to improving the process of attaching the quarter-wave plate to the first lens, and improves the processability of the first lens and the lens barrel on the basis of ensuring system assembly.

[0060] In the exemplary embodiments, the optical system of the present application can satisfy: 0 < (D0m-d1m) / (CT2 + T23 + CT3) < 2, where Dom is the outer diameter of the second side end surface of the lens barrel, d1m is the inner diameter of the second side of the first supporting element, CT2 is the central thickness of the second lens on the optical axis, T23 is the air gap from the second lens to the third lens on the optical axis, and CT3 is the central thickness of the third lens on the optical axis. Satisfying 0 < (D0m-d1m) / (CT2 + T23 + CT3) < 2 improves the structural rationalization of the entire lens space, increases the stability of the lens structure, and ensures the processability of the lens barrel and the supporting element.

[0061] In an example embodiment, the optical system of the present application can satisfy -500 < R1 / EP01+R4 / EP12 < -20, where R1 is the curvature radius of the first side surface of the first lens, EP01 is the distance between the first side surface of the lens barrel and the first side surface of the first abutting element along the optical axis, R4 is the curvature radius of the second side surface of the second lens, and EP12 is the distance between the second side surface of the first abutting element and the first side surface of the second abutting element along the optical axis. Satisfying -500 < R1 / EP01+R4 / EP12 < -20 controls the optical power of the first lens and the second lens, optimizes the light path, and ensures the reliability of the entire lens group.

[0062] In an example embodiment, the first lens group can have positive optical power, the second lens can have positive optical power or negative optical power, and the third lens can have positive optical power or negative optical power. Reasonably matching the optical power of each lens is conducive to correcting the system aberration.

[0063] In an example embodiment, at least one of the second lens and the third lens is a biconvex lens.

[0064] In an example embodiment, the sign of the optical power of the second lens and the sign of the optical power of the third lens are opposite.

[0065] In an example embodiment, the optical system of the present application can satisfy -2 < f2 / f3 < 0 and -4 < (f2+f3) / (d2s+d2m) < 0.5, where f2 is the effective focal length of the third lens, f3 is the effective focal length of the third lens, d2s is the inner diameter of the first side surface of the second abutting element, and d2m is the inner diameter of the second side surface of the second abutting element. Controlling the optical power of the second lens and the third lens and the inner diameters of the first side surface and the second side surface of the second abutting element is conducive to correcting the system aberration, improving the imaging quality, improving the machinability of the second abutting element, and improving the effective support function of the lens.

[0066] In an example embodiment, the optical system of the present application can include at least one diaphragm. The diaphragm can restrict the light path and control the light intensity. The diaphragm can be arranged at an appropriate position of the optical system, for example, the diaphragm can be arranged on the first side surface of the first lens.

[0067] In the exemplary embodiments, the effective focal length f of the optical system can be, for example, in the range of 26.0mm to 33.0mm, the effective focal length F1 of the first lens group can be, for example, in the range of 27.0mm to 245.0mm, the effective focal length f2 of the second lens can be, for example, in the range of -136.0mm to 256.0mm, and the effective focal length f3 of the third lens can be, for example, in the range of -670.0mm to 75.0mm.

[0068] According to some embodiments of the present application, the optical system according to the present application is a small-size optical system with high imaging quality. In applications, the optical system according to the exemplary embodiments of the present application can be suitable for VR devices. By reasonably setting the effective focal length, the maximum field of view angle, the entrance pupil diameter, and the central thickness, the refractive index, the Abbe number, the radius of curvature, and other parameters of the lenses of the optical system, and by reasonably setting the diaphragm parameters, the wide-angle purpose of the VR device can be met, and the chromatic aberration of the system can be corrected, and the imaging quality of the system can be improved. By setting the bearing elements between the lenses, the machining performance of the lenses can be improved, the sensitivity of the lenses can be reduced, the assembly yield can be improved, and the miniaturization target of the VR device can be met under the premise of ensuring the performance of the optical system.

[0069] The specific embodiments of the optical system applicable to the above embodiments are further described below with reference to the accompanying drawings.

[0070] Example 1

[0071] The following refers to Figures 2A to 3C An optical system according to Embodiment 1 of the present application is described. Figures 2A to 2C The structural schematic diagrams of the optical systems according to three embodiments in Embodiment 1 of the present application are shown.

[0072] As Figures 2A to 2C shown, the optical system sequentially includes, along the optical axis from the first side to the second side: a diaphragm STO, a reflective polarizing element RP, a quarter-wave plate QWP, a first lens E1, a partially reflective layer BS, a second lens E2, a third lens E3, and a display E4. Among them, the diaphragm STO and the display E4 are only schematically shown in Figure 2A .

[0073] In the embodiment, the reflective polarizing element RP has a first side S1 and a second side S2, the quarter-wave plate QWP has a first side S2 and a second side S3, and the first lens E1 has a first side S3 and a second side S4. That is, S2 is a common surface of the second side of the reflective polarizing element RP and the first side of the quarter-wave plate QWP, and the second side of the reflective polarizing element RP is attached to the first side of the quarter-wave plate QWP; S3 is a common surface of the second side of the quarter-wave plate QWP and the first side of the first lens E1, and the second side of the quarter-wave plate QWP is attached to the first side of the first lens E1. The second lens E2 has a first side S5 and a second side S6. The third lens E3 has a first side S7 and a second side S8.

[0074] The partial reflection layer BS is arranged on the second side S4 of the first lens E1. In the exemplary embodiment, the partial reflection layer can be a semi-transparent and semi-reflective film layer plated on the second side of the first lens E1. In the example, the partial reflection layer can be plated at the region of the second side of the first lens E1 away from the optical axis.

[0075] In the exemplary embodiment, the first side may, for example, be the human eye side, and the second side may, for example, be the display side. Referring to Figure 2A , the light emitted by the display E4 screen sequentially passes through the third lens E3, the second lens E2, the first lens E1, the quarter-wave plate QWP, and reaches the reflective polarizing element RP, is reflected at the reflective polarizing element RP and passes through the quarter-wave plate QWP and the first lens E1 again, and then the light beam is reflected again at the partial reflection layer BS on the second side of the first lens E1 and sequentially passes through the first lens E1, the quarter-wave plate QWP, the reflective polarizing element RP, passes through the stop STO and finally exits towards the human eye side.

[0076] Table 1 shows the basic parameters of the optical system of embodiment 1, wherein the units of the curvature radius and the thickness are millimeters (mm). In Table 1, only the correspondence between the surface numbers of part of the surfaces and part of the elements is exemplarily listed. Due to the problem of the common surface of the adjacent elements, it is not convenient to mark all the elements at the position of the common surface in Table 1.

[0077]

[0078]

[0079] Table 1

[0080] In embodiment 1, the first side and the second side of the reflective polarizing element RP, the quarter-wave plate QWP, the first lens E1, the second lens E2, and the third lens E3 are all aspherical surfaces, and the surface type x of each aspherical lens can be defined by, but not limited to, the following aspherical formula:

[0081]

[0082] wherein z is the depth of the aspherical surface (the perpendicular distance between a point on the aspherical surface at a distance y from the optical axis and the tangent plane at the vertex of the aspherical surface); c is the curvature of the vertex of the aspherical surface; K is the conic constant, is the radial distance; r n is the normalized radius; u is r / r n ; a m is the mth order Q con coefficient; Q m con is the mth order Q con polynomial. Table 2 below gives the high order term coefficients a0, a1, a2and a3that can be used for each aspherical surface in Example 1.

[0083] Face No. [a0] [a1] [a2] [a3] S1 9.0707E-02 5.0091E-02 -1.9326E-02 -4.2720E-03 S2 9.0707E-02 5.0091E-02 -1.9326E-02 -4.2720E-03 S3 9.0707E-02 5.0091E-02 -1.9326E-02 -4.2720E-03 S4 8.2077E-02 3.0319E-02 -1.8254E-02 7.9232E-04 S5 -3.3474E-01 -2.3464E-03 6.1916E-02 1.2839E-01 S6 3.1941E-01 9.4953E-02 -8.3416E-02 2.9775E-02 S7 -3.3290E-01 -8.6600E-02 7.0522E-02 -7.1153E-02 S8 2.9386E-01 1.2579E-01 -6.2367E-02 1.5146E-01

[0084] Table 2

[0085] Table 3 gives the numerical values of the maximum field of view FOV, the F-number Fno, the effective focal length f of the optical system, the effective focal length F1 of the first lens group (including the reflective polarizing element RP, the quarter wave plate QWP, the first lens E1 and the partial reflecting layer BS), the effective focal length f2 of the second lens E2, the effective focal length f3 of the third lens E3 and the structural parameters such as the barrel, the supporting element, etc. of the optical system in the three implementation manners in Example 1.

[0086]

[0087]

[0088] Table 3

[0089] Figure 2A The on-axis chromatic aberration curve of the optical system of Example 1 is shown, which represents the deviation of the converging focal points of light rays of different wavelengths after passing through the lens. Figure 2B The astigmatism curve of the optical system of Example 1 is shown, which represents the meridional image surface curvature and sagittal image surface curvature. Figure 2C The distortion curve of the optical system of Example 1 is shown, which represents the distortion size values corresponding to different half field angles. According to Figures 2A to 2C It can be seen that the optical system given in Example 1 can achieve good imaging quality.

[0090] Example 2

[0091] The following refers to Figures 4A to 5CAn optical system according to Embodiment 2 of the present application is described. In this and the following embodiments, the description of parts similar to Embodiment 1 will be omitted for brevity. Figures 4A to 4C The structural schematic diagram of the optical system according to three implementation manners in Embodiment 2 of the present application is shown.

[0092] As shown in Figures 4A to 4C , the optical system comprises, in order from the first side to the second side along the optical axis: a stop STO, a reflective polarizing element RP, a quarter-wave plate QWP, a first lens E1, a partially reflective layer BS, a second lens E2, a third lens E3, and a display E4. Among them, the stop STO and the display E4 are only schematically shown in Figure 4A .

[0093] In this embodiment, the reflective polarizing element RP has a first side S1 and a second side S2, the quarter-wave plate QWP has a first side S2 and a second side S3, and the first lens E1 has a first side S3 and a second side S4. That is, S2 is a common surface of the second side of the reflective polarizing element RP and the first side of the quarter-wave plate QWP, and the second side of the reflective polarizing element RP is in contact with the first side of the quarter-wave plate QWP; S3 is a common surface of the second side of the quarter-wave plate QWP and the first side of the first lens E1, and the second side of the quarter-wave plate QWP is in contact with the first side of the first lens E1. The second lens E2 has a first side S5 and a second side S6. The third lens E3 has a first side S7 and a second side S8.

[0094] The partially reflective layer BS is arranged on the second side S4 of the first lens E1. In an exemplary implementation manner, the partially reflective layer can be a semi-transparent and semi-reflective film layer plated on the second side of the first lens E1. In an example, the partially reflective layer can be plated at the area of the second side of the first lens E1 away from the optical axis.

[0095] In an exemplary implementation manner, the first side can be, for example, the human eye side, and the second side can be, for example, the display side. Referring to Figure 4A , the light emitted by the screen of the display E4 passes through the third lens E3, the second lens E2, the first lens E1, the quarter-wave plate QWP in order, reaches the reflective polarizing element RP, is reflected at the reflective polarizing element RP and passes through the quarter-wave plate QWP and the first lens E1 again, and then the light beam is reflected again at the partially reflective layer BS on the second side of the first lens E1 and passes through the first lens E1, the quarter-wave plate QWP, the reflective polarizing element RP in order, passes through the stop STO and finally exits towards the human eye side.

[0096] Table 4 shows the basic parameters of the optical system of Embodiment 2, where the units for radius of curvature and thickness are millimeters (mm). Table 4 only lists the correspondence between surface numbers and some components on a partial basis. Due to the issue of shared surfaces between adjacent components, it is inconvenient to mark all components at the locations of shared surfaces in Table 4. Table 5 shows the higher-order coefficients that can be used for each aspherical mirror in Embodiment 2, where each aspherical surface shape can be defined by formula (1) given in Embodiment 1 above.

[0097] Face No. Element Name Surface Type Radius of Curvature Thickness Refractive Index Abbe Number Refractive / Reflective Spherical Infinite Infinite STO Stop (STO) Spherical Infinite 15.0000 Refractive S1 Reflective Polarizing Element (RP) Aspherical -26.9152 0.2000 1.50 57.00 Refractive S2 Quarter Wave Plate (QWP) Aspherical -26.9152 0.2000 1.50 57.00 Refractive S3 First Optical Lens (E1) Aspherical -26.9152 4.7072 1.52 101.09 Refractive S4 Partial Reflective Element (BS) Aspherical -26.4877 -4.7072 1.52 101.09 Reflective S3 Quarter Wave Plate (QWP) Aspherical -26.9152 -0.2000 1.50 57.00 Refractive S2 Aspherical -26.9152 0.2000 1.50 57.00 Reflective S3 Aspherical -26.9152 4.7072 1.52 101.09 Refractive S4 Aspherical -26.4877 0.1000 Refractive S5 Second Optical Lens (E2) Aspherical 92.9950 12.0362 1.50 47.60 Refractive S6 Aspherical -49.5404 0.1000 Refractive S7 Third Optical Lens (E3) Aspherical -48.2066 1.9727 1.67 19.04 Refractive S8 Aspherical 471.9089 9.1768 Refractive S9 Display (E4) Spherical Infinite

[0098] Table 4

[0099] Face No. [a0] [a1] [a2] [a3] S1 -1.9980E-01 2.5055E-03 6.3828E-03 -1.0605E-03 S2 -1.9980E-01 2.5055E-03 6.3828E-03 -1.0605E-03 S3 -1.9980E-01 2.5055E-03 6.3828E-03 -1.0605E-03 S4 -2.3435E-01 2.1324E-02 5.3922E-03 -8.9875E-04 S5 -3.4499E-01 -2.7406E-01 5.5219E-02 1.0854E-01 S6 4.8859E-01 1.2283E-01 -2.4694E-02 5.0082E-02 S7 -4.1882E-01 -5.4365E-02 1.4223E-01 -2.0491E-01 S8 -6.8477E-01 -3.6569E-02 2.0075E-01 -1.5008E-01

[0100] Table 5

[0101] Table 6 provides the values ​​of the maximum field of view (FOV), aperture number (Fno), effective focal length (f), effective focal length (F1) of the first lens group (including the reflective polarizing element RP, quarter-wave plate QWP, first lens E1, and partial reflective layer BS), effective focal length (f2) of the second lens E2, and effective focal length (f3) of the third lens E3, as well as structural parameters such as the lens barrel and supporting elements, for the optical system under the three implementation methods in Example 2.

[0102]

[0103]

[0104] Table 6

[0105] Figure 5A The on-axis chromatic aberration curve of the optical system of Embodiment 2 is shown, which represents the deviation of light of different wavelengths from the convergence focal point after passing through the lens. Figure 5B The astigmatism curves of the optical system of Embodiment 2 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 5C The distortion curves of the optical system in Example 2 are shown, representing the distortion magnitudes corresponding to different half-field angles. According to... Figures 5A to 5C It can be seen that the optical system given in Example 2 can achieve good imaging quality.

[0106] Example 3

[0107] The following is for reference Figures 6A to 7C An optical system according to Embodiment 3 of this application is described. Figures 6A to 6C A schematic diagram of the structure of the optical system according to three embodiments of Embodiment 3 of this application is shown.

[0108] like Figures 6A to 6CAs shown, the optical system comprises, along the optical axis, in order from the first side to the second side: the optical stop STO, the reflective polarizer RP, the quarter-wave plate QWP, the first lens E1, the partially reflective layer BS, the second lens E2, the third lens E3, and the display S9. Among them, the optical stop STO and the display E4 only have the optical axis as the common surface, and the other elements have the common surface as the shared surface. Figure 6A are shown schematically in FIG. 6.

[0109] In the present embodiment, the reflective polarizer RP has a first side S1 and a second side S2, the quarter-wave plate QWP has a first side S2 and a second side S3, and the first lens E1 has a first side S3 and a second side S4. That is, S2 is the common surface of the second side of the reflective polarizer RP and the first side of the quarter-wave plate QWP, and the second side of the reflective polarizer RP and the first side of the quarter-wave plate QWP are in contact; S3 is the common surface of the second side of the quarter-wave plate QWP and the first side of the first lens E1, and the second side of the quarter-wave plate QWP and the first side of the first lens E1 are in contact. The second lens E2 has a first side S5 and a second side S6. The third lens E3 has a first side S7 and a second side S8.

[0110] The partially reflective layer BS is disposed on the first side S5 of the second lens E2. In an exemplary embodiment, the partially reflective layer can be a semi-transparent and semi-reflective film layer plated on the first side of the second lens E2. In an example, the partially reflective layer can be plated at the region of the first side of the second lens E2 away from the optical axis.

[0111] In an exemplary embodiment, the first side can be the human eye side, and the second side can be the display side. Referring to FIG. 6, Figure 6A As shown in FIG. 6, the light emitted by the display E4 screen passes through the third lens E3, the second lens E2, the first lens E1, the quarter-wave plate QWP in order, reaches the reflective polarizer RP, is reflected at the reflective polarizer RP, and again passes through the quarter-wave plate QWP, the first lens E1 to reach the first side of the second lens E2, and then the light beam is again reflected at the partially reflective layer BS on the first side of the second lens E2 and passes through the first lens E1, the quarter-wave plate QWP, the reflective polarizer RP in order, passes through the optical stop STO and finally exits towards the human eye side.

[0112] Table 7 shows the basic parameters of the optical system of Example 3, wherein the units of the curvature radius and the thickness are millimeters (mm). In Table 7, only the correspondence between the surface numbers of some surfaces and some elements is exemplarily listed. Due to the problem of the shared surface of the adjacent elements, it is not convenient to mark all the elements at the position of the shared surface in Table 7. Table 8 shows the high-order term coefficients of the aspherical surfaces that can be used in the optical system of Example 3, wherein each aspherical surface can be defined by the formula (1) given in Example 1.

[0113] Face No. Element Name Surface Type Radius of Curvature Thickness Refractive Index Abbe Number Refractive / Reflective Spherical Infinite Infinite STO Stop (STO) Spherical Infinite 20.0461 Refractive S1 Reflective Polarizing Element (RP) Aspherical -65.4535 0.2000 1.50 57.00 Refractive S2 Quarter Wave Plate (QWP) Aspherical -65.4535 0.2000 1.50 57.00 Refractive S3 First Optical Lens (E1) Aspherical -65.4535 8.1673 1.48 60.00 Refractive S4 Aspherical -43.8562 0.5002 Refractive S5 Partial Reflective Element (BS) Aspherical -49.7848 -0.5002 Reflective S4 Aspherical -43.8562 -8.1673 1.48 60.00 Refractive S3 Quarter Wave Plate (QWP) Aspherical -65.4535 -0.2000 1.50 57.00 Refractive S2 Aspherical -65.4535 0.2000 1.50 57.00 Reflective S3 Aspherical -65.4535 8.1673 Refractive S4 Aspherical -43.8562 0.5002 Refractive S5 Second Optical Lens (E2) Aspherical -49.7848 0.6000 1.68 19.00 Refractive S6 Aspherical -109.4636 0.1000 Refractive S7 Third Optical Lens (E3) Aspherical 85.7409 17.5544 1.52 41.42 Refractive S8 Aspherical -66.7595 2.2056 Refractive S9 Display (E4) Spherical Infinite

[0114] Table 7

[0115] Serial No. [a0] [a1] [a2] [a3] S1 -3.3044E-01 4.1575E-02 -9.0531E-03 4.0696E-03 S2 -3.3044E-01 4.1575E-02 -9.0531E-03 4.0696E-03 S3 -3.3044E-01 4.1575E-02 -9.0531E-03 4.0696E-03 S4 -1.3029E-01 -7.7634E-02 1.4606E-01 -4.6677E-02 S5 -9.6928E-02 1.0769E-01 -8.8496E-02 2.6431E-02 S6 -1.5446E+00 -5.7178E-03 -1.3545E-02 4.0895E-02 S7 -4.1101E-01 -2.7284E-01 1.3823E-02 6.1793E-02 S8 3.1523E-01 3.0858E-01 -8.3960E-02 2.5258E-02

[0116] Table 8

[0117] Table 9 gives the numerical values of the maximum field angle FOV, the F-number Fno, the effective focal length f of the optical system, the effective focal length F1 of the first lens group (including the reflective polarizing element RP, the quarter-wave plate QWP and the first lens E1), the effective focal length f2 of the second lens E2 and the effective focal length f3 of the third lens E3, as well as the structure parameters such as the barrel, the supporting element, etc. of the optical system in the three embodiments of Example 3.

[0118]

[0119]

[0120] Table 9

[0121] Figure 7A The on-axis chromatic aberration curve of the optical system of Example 3 is shown, which represents the deviation of the convergent focal points of light rays of different wavelengths after passing through the lens. Figure 7B The astigmatism curve of the optical system of Example 3 is shown, which represents the meridional image surface curvature and sagittal image surface curvature. Figure 7C The distortion curve of the optical system of Example 3 is shown, which represents the distortion size values corresponding to different half field angles. According to the formula Figures 7A to 7C It can be seen that the optical system given in Example 3 can achieve good imaging quality.

[0122] In summary, the relationships of the optical systems of Example 1 to Example 4 shown in Table 10.

[0123]

[0124] Table 10

[0125] The present application also provides an optical device, which can be a separate projection device such as a projector, or a projection module integrated on a mobile electronic device such as VR. The optical device is equipped with the optical system described above.

[0126] The above description is only the preferred embodiment of the present application and the explanation of the technical principles. It should be understood by those skilled in the art that the protective scope of the present application is not limited to the technical solutions formed by the specific combinations of the above technical features, and should also cover other technical solutions formed by the combinations of the above technical features or their equivalent features without departing from the concept of the present application. For example, the technical solutions formed by the mutual replacement of the above features and the technical features disclosed in the present application (but not limited to) with similar functions.

Claims

1. Optical system, characterized in that The optical system comprises: a lens group comprising, in order from a first side to a second side along an optical axis, a first lens group, a second lens, and a third lens, wherein the first lens group has positive refractive power, comprises, in order from the first side to the second side, a reflective polarizing element, a quarter-wave plate, and a first lens, and a second side surface of the reflective polarizing element is in abutment with a first side surface of the quarter-wave plate, a second side surface of the quarter-wave plate is in abutment with a first side surface of the first lens; at least one abutting element comprising a second abutting element arranged on and in contact with a second side surface of the second lens; and a lens barrel for accommodating the lens group and the at least one abutting element; wherein the optical system further comprises a partial reflection layer arranged on a second side surface of the first lens or a first side surface of the second lens; a refractive power VRP of the reflective polarizing element, an effective focal length F1 of the first lens group, and an outer diameter D0s of a first side end surface of the lens barrel satisfy: 20.79≤VRP×F1 / D0s≤201.97; and an effective focal length f2 of the second lens, an effective focal length f3 of the third lens, an inner diameter d2s of a first side surface of the second abutting element, and an inner diameter d0m of a second side end surface of the lens barrel satisfy: 0<|f2+f3| / (d2s+d0m)≤3.56 and -1.81≤f2 / f3≤-0.38; a number of lenses having refractive power in the optical system is three; the first lens has positive refractive power, a first side surface thereof is concave, and a second side surface thereof is convex; a second side surface of the second lens is convex; at least one of the second lens and the third lens is a biconvex lens; a sign of refractive power of the second lens and a sign of refractive power of the third lens are opposite in sign; the first side is an eye side, and the second side is a display side.

2. The optical system of claim 1, wherein an inner diameter d0m of a second side end surface of the lens barrel, an inner diameter d0s of a first side end surface of the lens barrel, and a radius of curvature R1 of a first side surface of the first lens satisfy: -5.01≤(d0m+d0s) / R1≤-1.

73.

3. The optical system according to claim 1, wherein a radius of curvature R1 of a first side surface of the first lens and a radius of curvature R4 of a second side surface of the second lens satisfy: 1.5×R1>R4.

4. The optical system of claim 1, wherein a radius of curvature of a first side surface and a second side surface of the reflective polarizing element is the same; and a radius of curvature RRP of a second side surface of the reflective polarizing element, a radius of curvature R4 of a second side surface of the second lens, an inner diameter d2m of a second side surface of the second abutting element, and an inner diameter d0s of a first side end surface of the lens barrel satisfy: -7.32≤(RRP1+R4) / (d2m+d0s)≤-0.

51.

5. The optical system of claim 1, wherein an outer diameter D0m of a second side end surface of the lens barrel, a maximum height L of the lens barrel in a direction of the optical axis, an effective focal length f of the optical system, and a sum ΣCT of central thicknesses of the first lens, the second lens, and the third lens in the optical axis satisfy: 2.97 ≤ D0m / L x f / ∑CT ≤ 3.

61.

6. The optical system of claim 1, wherein Abbe number V2 of the second lens, Abbe number V3 of the third lens, Abbe number V1 of the first lens, inner diameter d2s of the first side surface of the second bearing element, inner diameter d2m of the second side surface of the second bearing element, and outer diameter D0s of the first side end surface of the lens barrel satisfy: 0.89 ≤ (V2 + V3) / V1 x (d2s + d2m) / D0s ≤ 3.

49.

7. The optical system of claim 1, wherein Outer diameter D2s of the first side surface of the second bearing element, maximum field angle FOV of the optical system, and on-axis distance TrRPrBS from the first side surface of the reflective polarizing element to the surface of the lens where the partial reflection layer is located satisfy: 6.40 ≤ D2s x tan(FOV / 2) / TrRPrBS ≤ 18.

24.

8. The optical system of claim 1, wherein, Maximum thickness CP2 of the second bearing element in the direction of the optical axis, F-number Fno of the optical system, and air interval T12 of the first lens to the second lens on the optical axis satisfy: 6 < CP2 x Fno / T12 ≤ 99.

64.

9. The optical system according to any one of claims 1 to 8, characterized in that, Refractive index NRP of the reflective polarizing element, refractive index NQWP of the quarter-wave plate, effective focal length F1 of the first lens group, and outer diameter D0s of the first side end surface of the lens barrel satisfy: 1.10 ≤ (NRP + NQWP) x F1 / D0s ≤ 10.

64.

10. The optical system according to any one of claims 1 to 8, characterized in that, Maximum height L of the lens barrel in the direction of the optical axis, F-number Fno of the optical system, outer diameter D0s of the first side end surface of the lens barrel, and outer diameter D0m of the second side end surface of the lens barrel satisfy: 24.34 ≤ L x Fno / |D0s - D0m| ≤ 104.

74.

11. The optical system according to any one of claims 1 to 8, characterized in that Distance TD from the first side surface of the first lens to the second side surface of the third lens on the optical axis, central thickness CTRP of the reflective polarizing element in the direction of the optical axis, central thickness CTQWP of the quarter-wave plate in the direction of the optical axis, effective focal length f of the optical system, maximum field angle FOV of the optical system, and outer diameter D0m of the second side end surface of the lens barrel satisfy: 4.85 ≤ (TD + CTRP + CTQWP) / (f x tan(FOV / 2) - D0m / 2) ≤ 34.

03.

12. The optical system according to any one of claims 1 to 8, characterized in that The first side surface and the second side surface of the quarter-wave plate have the same radius of curvature; and Distance SAG11 from the intersection of the first side surface of the first lens on the optical axis to the maximum effective radius vertex of the first side surface of the first lens, radius of curvature RQWP of the second side surface of the quarter-wave plate, outer diameter D0s of the first side end surface of the lens barrel, and central thickness CT1 of the first lens on the optical axis satisfy: 0.55 ≤ SAG11 / RQWP x D0s / CT1 ≤ 3.

30.

13. The optical system of claim 1, wherein, The at least one bearing element further includes a first bearing element disposed on and in contact with the second side surface of the first lens; and The at least one bearing element further includes a first bearing element disposed on and in contact with the second side surface of the first lens; and An outer diameter D0m of the second side end surface of the lens barrel, an inner diameter d1m of the second side surface of the first abutting element, a center thickness CT2 of the second lens on the optical axis, an air interval T23 of the second lens to the third lens on the optical axis, and a center thickness CT3 of the third lens on the optical axis satisfy: 0.90 ≤ (D0m - d1m) / (CT2 + T23 + CT3) ≤ 1.

80.

14. The optical system of claim 13, wherein, A curvature radius R1 of the first side surface of the first lens, a distance EP01 of the first side end surface of the lens barrel to the first side surface of the first abutting element in the direction of the optical axis, a curvature radius R4 of the second side surface of the second lens, and a distance EP12 of the second side surface of the first abutting element to the first side surface of the second abutting element in the direction of the optical axis satisfy: -469.14 ≤ R1 / EP01 + R4 / EP12 ≤ -20.

60.

15. An optical system characterized by comprising: Comprising: a lens group comprising, in order from a first side to a second side along an optical axis, a first lens group, a second lens, and a third lens, wherein the first lens group comprises, in order from the first side to the second side, a reflective polarizing element, a quarter-wave plate, and a first lens, and a second side surface of the reflective polarizing element is continuous with a first side surface of the quarter-wave plate, and a second side surface of the quarter-wave plate is continuous with a first side surface of the first lens; at least one abutting element comprising a second abutting element disposed on and in contact with a second side surface of the second lens; a lens barrel for accommodating the lens group and the at least one abutting element; wherein the optical system further comprises a partial reflection layer disposed on a second side surface of the first lens or a first side surface of the second lens; the first lens has a positive refractive power, the first side surface of the first lens is a concave surface, and the second side surface of the first lens is a convex surface; the second side surface of the second lens is a convex surface; at least one of the second lens and the third lens is a biconvex lens; a sign of a refractive power of the second lens and a sign of a refractive power of the third lens are opposite in sign; the first side is an eye side, and the second side is a display side; a number of lenses having refractive power in the optical system is three; and the optical system satisfies: -1.81 ≤ f2 / f3 ≤ -0.38 and -3.70 ≤ (f2 + f3) / (d2s + d2m) ≤ 0.01, where f2 is an effective focal length of the third lens, f3 is an effective focal length of the third lens, d2s is an inner diameter of a first side surface of the second abutting element, and d2m is an inner diameter of a second side surface of the second abutting element.

16. An optical device, characterized by comprising the optical system of any one of claims 1 to 15. comprising the optical system of any one of claims 1 to 15.

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