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 barrel, a lens assembly, a reflection assembly and a spacer assembly arranged in the lens barrel. The lens assembly comprises a first lens, a second lens and a third lens arranged in sequence from a first side to a second side along an optical axis. The spacer assembly comprises at least one spacer arranged between two adjacent lenses in the lens assembly. The lens barrel has a front end face facing the first side and a rear end face facing the second side. The maximum outer diameter of the front end face of the lens barrel is smaller than the maximum outer diameter of the rear end face of the lens barrel. The inner diameter d0m of the rear end face of the lens barrel, the maximum half field of view HFOV of the optical system and the maximum height L of the lens barrel along the optical axis direction satisfy the following relationship: 1.0 < tan(HFOV) x d0m / L < 1.5.

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] At present, there is still a large space for optimization of the VR process, which needs to be further developed in the future. Currently, there are mainly the following four problems:

[0003] First, the light path loss is high: in the design mode of folded light path, the light needs to pass through the half-transmission half-reflection film twice, and each time the intensity loss is 50%. Therefore, the theoretical highest optical efficiency of the VR scheme is only 25%. In addition, the reflection polarizing film will also lose 10%. The overall optical utilization rate is only 10-20%. Therefore, the VR design scheme needs to be equipped with a high-brightness display screen, such as Micro OLED, Micro LED, etc.

[0004] Second, there are artifacts: under the effect of birefringence, light is easy to produce artifacts when it is folded back in the lens. The influence needs to be eliminated by a polarizing film. However, the accurate polarizing film has high requirements for materials, heat resistance, precision machining, etc.

[0005] Third, the production difficulty and cost are high: the core optical film in the VR design has high requirements for materials and multi-lens bonding technology. Only a few enterprises in the world can meet the requirements. The production yield is low, and the cost is high. The cost of optical film for a set of lenses (monocular) is close to 100 yuan RMB.

[0006] Fourth, the actual effect does not reach the ideal level: due to the compression of the lens diameter and other factors, the resolution and field of view have not reached the ideal level.

[0007] Therefore, in order to improve the experience effect of use, further shorten the length of the optical device body and improve the imaging quality, the 3-piece catadioptric optical device scheme has become one of the current research hotspots. SUMMARY

[0008] The first aspect of the present application provides an optical system, comprising: a lens barrel, and a lens assembly, a reflection assembly and a spacer assembly arranged in the lens barrel, wherein the lens assembly comprises, in sequence from a first side to a second side along an optical axis, a first lens, a second lens and a third lens; the spacer assembly comprises at least one spacer, and the spacer is arranged between two adjacent lenses in the lens assembly; the lens barrel has a front end face facing the first side and a rear end face facing the second side, and the maximum outer diameter of the front end face of the lens barrel is smaller than the maximum outer diameter of the rear end face of the lens barrel; and the inner diameter d0m of the rear end face of the lens barrel, the maximum half field of view HFOV of the optical system and the maximum height L of the lens barrel along the optical axis direction satisfy: 1.0 < tan(HFOV) x d0m / L < 1.5.

[0009] In one embodiment, the spacer assembly comprises a first spacer disposed between the first lens and the second lens and in contact with the first lens; wherein a radius of curvature R2 of the second side surface of the first lens, an outer diameter D1s of the first side surface of the first spacer, and an inner diameter d1s of the first side surface of the first spacer satisfy: 3.0 < |R2| / (D1s-d1s) < 18.0.

[0010] In one embodiment, the spacer assembly comprises a first spacer disposed between the first lens and the second lens and in contact with the first lens; wherein a radius of curvature R3 of the first side surface of the second lens, an outer diameter D1m of the second side surface of the first spacer, and an inner diameter d1m of the second side surface of the first spacer satisfy: -5.0 < R3 / (D1m-d1m) < -2.0.

[0011] In one embodiment, the spacer assembly comprises a first spacer disposed between the first lens and the second lens and in contact with the first lens, and a second spacer disposed between the second lens and the third lens and in contact with the second lens; wherein a combined focal length f12 of the first lens and the second lens, a central thickness CT1 of the first lens in the optical axis direction, a central thickness CT2 of the second lens in the optical axis direction, and a separation distance EP12 of the first spacer and the second spacer in the optical axis direction satisfy: 17.0 < f12 / (CT1+CT2+EP12) < 335.0.

[0012] In one embodiment, the spacer assembly comprises a second spacer disposed between the second lens and the third lens and in contact with the second lens; wherein an outer diameter D2s of the first side surface of the second spacer, an inner diameter d2s of the first side surface of the second spacer, and a radius of curvature R4 of the second side surface of the second lens satisfy: 0.5 < (D2s+d2s) / |R4| < 4.0.

[0013] In one embodiment, the spacer assembly comprises a second spacer disposed between the second lens and the third lens and in contact with the second lens; wherein an effective focal length f3 of the third lens, a maximum thickness CP2 of the second spacer in the optical axis direction, and an air separation T23 of the second lens and the third lens in the optical axis direction satisfy: 17.0 < |f3| / (CP2+T23) < 92.0.

[0014] In one embodiment, the spacer assembly comprises a second spacer disposed between the second lens and the third lens and in contact with the second lens; wherein an outer diameter D2s of the first side surface of the second spacer, an outer diameter D2m of the second side surface of the second spacer, and a radius of curvature R5 of the first side surface of the third lens satisfy: 0.3 < (D2s+D2m) / |R5| < 4.5.

[0015] In one embodiment, the spacer assembly comprises a second spacer disposed between the second lens and the third lens and in contact with the second lens; wherein the radius of curvature R6 of the second side surface of the third lens, the maximum thickness CP2 of the second spacer in the direction of the optical axis, and the central thickness CT3 of the third lens in the optical axis satisfy: 2.5 < |R6| / (EP12+CP2+CT3) < 4.0.

[0016] In one embodiment, the spacer assembly comprises a first spacer disposed between the first lens and the second lens and in contact with the first lens; wherein the radius of curvature R1 of the first side surface of the first lens, the radius of curvature R2 of the second side surface of the first lens, the distance EP01 of the front end surface of the lens barrel and the first side surface of the first spacer in the direction of the optical axis, and the central thickness CT1 of the first lens in the optical axis satisfy: 3.0 < |R1+R2| / (EP01+CT1) < 19.0.

[0017] In one embodiment, the radius of curvature R1 of the first side surface of the first lens and the inner diameter d0s of the front end surface of the lens barrel satisfy: 1.0 < |R1| / d0s < 4.0.

[0018] In one embodiment, the spacer assembly comprises a first spacer disposed between the first lens and the second lens and in contact with the first lens, and a second spacer disposed between the second lens and the third lens and in contact with the second lens; wherein the maximum thickness CP1 of the first spacer in the direction of the optical axis, the maximum thickness CP2 of the second spacer in the direction of the optical axis, the effective focal length f1 of the first lens, and the effective focal length f2 of the second lens satisfy: 1.5 < |CP2×f2 / (CP1×f1)| < 7500.0.

[0019] In one embodiment, the outer diameter D0m of the rear end surface of the lens barrel and the radius of curvature R6 of the second side surface of the third lens satisfy: 1.0 < D0m / |R6| < 2.5.

[0020] In one embodiment, the effective focal length f1 of the first lens, the effective focal length f2 of the second lens, and the effective focal length f3 of the third lens satisfy: 0.01 < (f1+f3) / |f2| < 2.5.

[0021] In one embodiment, the maximum height L of the lens barrel in the direction of the optical axis, the sum ∑CT of the central thicknesses of the first lens to the third lens in the optical axis, and the sum ∑AT of the air gaps between any two adjacent lenses among the first lens to the third lens in the optical axis satisfy: 3.5 < L / ∑CT+L / ∑AT < 7.5.

[0022] In one embodiment, the reflective assembly includes a reflective polarizing element, a quarter-wave plate, and a partial reflective layer, wherein the reflective polarizing element and the quarter-wave plate are disposed on a second side of the second lens, and the partial reflective layer is disposed on a second side of the third lens.

[0023] A second aspect of this application also provides an optical device comprising an optical system provided in at least one of the above embodiments.

[0024] The optical system provided in this application is a three-element catadioptric optical system, which features good projection quality, small overall length, and good manufacturability. The optical system provided in this application satisfies 1.0 < tan(HFOV) × d0m / L < 1.5, effectively constraining the field of view of the optical system, thus enabling the system to meet the characteristics of a large field of view. Simultaneously, by constraining the inner diameter of the rear end face of the lens barrel, the radial step structure of the system is reduced, improving the assembly yield of the lens. Furthermore, by constraining the external dimensions of the lens barrel, the external dimensions of the lens barrel are minimized while ensuring manufacturability, thereby reducing the overall size of the device and avoiding artifacts. Attached Figure Description

[0025] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments, taken in conjunction with the accompanying drawings. In the drawings:

[0026] Figure 1 A structural layout diagram of an optical system according to this application is shown;

[0027] Figure 2 A schematic diagram showing some parameters of an optical system according to this application is provided;

[0028] Figures 3A to 3D A schematic diagram of the structure of the optical system according to Embodiment 1 of this application is shown;

[0029] Figures 4A to 4C The on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the optical system according to Embodiment 1 of this application are shown respectively.

[0030] Figure 5A and Figure 5B A schematic diagram of the structure of the optical system according to Embodiment 2 of this application is shown;

[0031] Figures 6A to 6C The on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the optical system according to Embodiment 2 of this application are shown respectively.

[0032] Figure 7A and Figure 7B A schematic diagram of the structure of the optical system according to Embodiment 3 of this application is shown; and

[0033] Figures 8A to 8C The on-axis chromatic aberration curve, astigmatism curve, and distortion curve of the optical system according to Embodiment 3 of this application are shown respectively. Detailed Implementation

[0034] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0035] It should be noted that in this specification, the terms "first," "second," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of this application, the first lens discussed below may also be referred to as the second lens, and the second lens may also be referred to as the first lens.

[0036] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0037] In this paper, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity 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 location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region.

[0038] It should also be understood that the terms "comprising," "including," "having," "containing," 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. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0039] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having a meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formalized sense, unless expressly so specified herein.

[0040] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0041] The features, principles and other aspects of this application will be described in detail below with reference to the accompanying drawings and embodiments.

[0042] An optical system according to an exemplary embodiment of this application includes: a lens barrel and a lens assembly, a reflective assembly, and a spacer assembly disposed within the lens barrel. The lens assembly has a refractive function, the reflective assembly has a reflective function, and the spacer assembly has a supporting and light-shielding function.

[0043] In an exemplary embodiment, the lens barrel has a front end face facing a first side and a rear end face facing a second side, wherein the maximum outer diameter of the front end face is smaller than the maximum outer diameter of the rear end face. Exemplarily, the lens barrel may be a one-piece lens barrel.

[0044] The lens assembly of an optical system according to an exemplary embodiment of this application may include three lenses with optical power, namely a first lens, a second lens, and a third lens. These three lenses are arranged sequentially along the optical axis from the first side to the second side. Any two adjacent lenses among the first to third lenses may have a spacing distance.

[0045] The spacer assembly of the optical system according to an exemplary embodiment of this application may include at least one spacer disposed between two adjacent lenses in the lens assembly. Exemplarily, the spacer assembly may include a first spacer disposed between the first lens and the second lens and in contact with the first lens. Exemplarily, the spacer assembly may include a second spacer disposed between the second lens and the third lens and in contact with the second lens. It should be understood that this application does not specifically limit the number of spacers; any number of spacers may be included between any two lenses, and the entire optical system may also include any number of spacers. Spacers help the optical system intercept excess reflective light paths, reducing stray light and ghosting. Adding auxiliary support between the spacer and the lens barrel helps improve problems such as poor assembly stability and low performance yield caused by large lens differences. By reasonably setting the number, thickness, inner diameter, and outer diameter of the spacers, it is beneficial to improve the assembly of the optical system, block stray light, and improve the projection quality of the optical system.

[0046] The reflective assembly of an optical system according to an exemplary embodiment of this application includes at least one reflective element. Exemplarily, the reflective assembly may include a reflective polarizing element, a quarter-wave plate, and a partially reflective layer. The partially reflective layer has a semi-transparent, semi-reflective function. In an exemplary embodiment, the reflective polarizing element and the quarter-wave plate may be placed on a second side of a second lens, and the partially reflective layer may be placed on a second side of a third lens.

[0047] In an exemplary embodiment, the reflective polarizing element and the quarter-wave plate are combined, and the desired structure can be obtained in a single attachment process, instead of two attachment processes. This reduces the angular position error caused by attachment and improves the imaging quality.

[0048] In an exemplary embodiment, the optical system may further include an emitting portion disposed on the second side of the third lens. The optical system provided in this application can be applied to, for example, VR devices, where the first side can be, for example, the human eye side, and the second side can be, for example, the display side or the image source side. Accordingly, the emitting portion can be a display screen.

[0049] Figure 1 The diagram shows the structural layout of an optical system according to this application. Figure 1 The optical system shown includes, in sequence along the optical axis from the first side to the second side: an aperture stop STO, lens assemblies E1 to E3, a reflection assembly W, a spacer assembly (not shown), and an emitting part F. The reflection assembly W includes a reflective polarizing element and a quarter-wave plate disposed on the second side of the second lens, and the reflection assembly W also includes a partial reflective layer disposed on the second side of the third lens. Figure 1 The receiving part J can be, for example, a human eye.

[0050] In an exemplary embodiment, the light emitted by the emitting unit passes through the third lens and reaches the reflective polarizing element disposed on the second side of the second lens. It is reflected by the reflective polarizing element and passes through the third lens again. Subsequently, the light beam is reflected again at a partial reflective layer on the second side of the third lens and passes through the third lens, the reflective polarizing element, the second lens and the first lens in sequence. It passes through the aperture and is finally received by the receiving unit (e.g., the human eye).

[0051] The optical system according to the exemplary embodiments of this application can reflect light in a certain polarization direction and transmit light orthogonal to that polarization direction by setting a reflective polarizing element; the polarization state of light can be changed by setting a quarter-wave plate; reflection and transmission can be achieved through a partial reflective layer, which can make the optical path of the system reflect and reverse, which is beneficial to shortening the length of the optical system.

[0052] Figure 2 A schematic diagram showing some parameters of an optical system according to this application is provided. Those skilled in the art will understand that some lens parameters commonly used in the art, such as the center thickness CT1 of the first lens on the optical axis, are not shown. Figure 1 As shown in the figure, Figure 1 The following is merely an example illustrating some parameters of the lens barrel and spacer of an optical system according to this application, to facilitate a better understanding of the invention. Figure 1 As shown, L represents the maximum height of the lens barrel along the optical axis, EP01 represents the distance between the front end face of the lens barrel and the first side face of the first spacer along the optical axis, EP12 represents the spacing distance between the first spacer and the second spacer along the optical axis, CP1 represents the maximum thickness of the first spacer along the optical axis, CP2 represents the maximum thickness of the second spacer along the optical axis, D0s represents the outer diameter of the front end face of the lens barrel, d0s represents the inner diameter of the front end face of the lens barrel, D1s represents the outer diameter of the first side face of the first spacer, d1s represents the inner diameter of the first side face of the first spacer, d2s represents the inner diameter of the first side face of the second spacer, d2m represents the inner diameter of the second side face of the second spacer, D2s represents the outer diameter of the first side face of the second spacer, D2m represents the outer diameter of the second side face of the second spacer, d0m represents the inner diameter of the rear end face of the lens barrel, and D0m represents the outer diameter of the rear end face of the lens barrel.

[0053] In an exemplary embodiment, the optical system of this application satisfies: 1.0 < tan(HFOV) × d0m / L < 1.5, where d0m is the inner diameter of the rear end face of the lens barrel, HFOV is the maximum half-field-of-view angle of the optical system, and L is the maximum height of the lens barrel along the optical axis. Satisfying 1.0 < tan(HFOV) × d0m / L < 1.5 effectively constrains the field-of-view angle of the optical system, thus enabling the system to meet the characteristics of a large field of view. Simultaneously, by constraining the inner diameter of the rear end face of the lens barrel, the radial step structure of the system is reduced, improving the assembly yield of the lens. Furthermore, by constraining the external dimensions of the lens barrel, the external dimensions of the lens barrel are minimized while ensuring its manufacturability, thereby reducing the overall size of the device and avoiding artifacts.

[0054] In an exemplary embodiment, the optical system of this application satisfies: 3.0 < |R2| / (D1s-d1s) < 18.0, where R2 is the radius of curvature of the second side surface of the first lens, D1s is the outer diameter of the first side surface of the first spacer, and d1s is the inner diameter of the first side surface of the first spacer. Satisfying 3.0 < |R2| / (D1s-d1s) < 18.0 restricts the radius of curvature of the second side surface of the first lens, which helps to reduce the sensitivity of the first lens and thus improve the assembly yield. Secondly, restricting the inner and outer diameters of the first side surface of the first spacer between the first lens and the second lens and in contact with the first lens helps to ensure its manufacturability.

[0055] In an exemplary embodiment, the optical system of this application satisfies: -5.0 < R3 / (D1m-d1m) < -2.0, where R3 is the radius of curvature of the first side surface of the second lens, D1m is the outer diameter of the second side surface of the first spacer, and d1m is the inner diameter of the second side surface of the first spacer. Satisfying -5.0 < R3 / (D1m-d1m) < -2.0, by controlling the radius of curvature of the first side surface of the second lens, helps to reduce the sensitivity of the second lens, thereby ensuring good imaging quality of the system on the axis; secondly, controlling the inner and outer diameters of the second side surface of the first spacer between the first and second lenses and in contact with the first lens ensures its manufacturability.

[0056] In an exemplary embodiment, the optical system of this application satisfies: 17.0 < f12 / (CT1+CT2+EP12) < 335.0, where f12 is the combined focal length of the first lens and the second lens, CT1 is the center thickness of the first lens on the optical axis, CT2 is the center thickness of the second lens on the optical axis, and EP12 is the spacing between the first spacer and the second spacer along the optical axis. Satisfying 17.0 < f12 / (CT1+CT2+EP12) < 335.0, the optical power of the first lens and the second lens is reasonably allocated, which is beneficial to controlling the contribution of the aberrations of the two lenses, balancing the aberrations generated by other optical elements, and keeping the system aberrations at a reasonable level. Controlling CT1, CT2, and EP12 is beneficial to controlling the edge thickness of the first lens and the second lens and the distance between the two spacers, so that the optical system achieves the optimal forming structure and assembly stability.

[0057] In an exemplary embodiment, the optical system of this application satisfies: 0.5 < (D2s + d2s) / |R4| < 4.0, where D2s is the outer diameter of the first side of the second spacer, d2s is the inner diameter of the first side of the second spacer, and R4 is the radius of curvature of the second side of the second lens. Satisfying 0.5 < (D2s + d2s) / |R4| < 4.0 can reduce on-axis chromatic aberration by adjusting the radius of curvature of the second side of the second lens, but it also makes this position more sensitive and prone to stray light. Further, by controlling the outer and inner diameters of the first side of the second spacer, the sensitivity at this position is reduced, thus improving the image quality. Secondly, controlling the outer and inner diameters of the first side of the second spacer, while ensuring its supporting function, is beneficial to improving the manufacturability of the second spacer and also to achieving miniaturization of the optical system.

[0058] In an exemplary embodiment, the optical system of this application satisfies: 17.0 < |f3| / (CP2+T23) < 92.0, where f3 is the effective focal length of the third lens, CP2 is the maximum thickness of the second spacer along the optical axis, and T23 is the air gap between the second and third lenses on the optical axis. Satisfying 17.0 < |f3| / (CP2+T23) < 92.0, and reasonably setting the thickness of the second spacer and the air gap between the second and third lenses, is beneficial for effectively absorbing excess edge light after refraction by the third lens, preventing it from entering the subsequent optical system and improving the system's imaging quality. By controlling this conditional expression, the thickness of each component inside the lens barrel can be reasonably allocated, which is beneficial for lens assembly.

[0059] In an exemplary embodiment, the optical system of this application satisfies: 0.3 < (D2s + D2m) / |R5| < 4.5, where D2s is the outer diameter of the first side of the second spacer, D2m is the outer diameter of the second side of the second spacer, and R5 is the radius of curvature of the first side of the third lens. Satisfying 0.3 < (D2s + D2m) / |R5| < 4.5 controls the radius of curvature of the third lens, which is beneficial for light convergence, thereby reducing the screen size. By controlling the outer diameters of the first and second sides of the second spacer, on the one hand, it is beneficial to improve lens stray light, and on the other hand, it is beneficial to optimize the bearing relationship between the second lens, the second spacer, and the third lens, thereby improving assembly stability.

[0060] In an exemplary embodiment, the optical system of this application satisfies: 2.5 < |R6| / (EP12+CP2+CT3) < 4.0, where R6 is the radius of curvature of the second side of the third lens, CP2 is the maximum thickness of the second spacer along the optical axis, and CT3 is the center thickness of the third lens along the optical axis. Satisfying 2.5 < |R6| / (EP12+CP2+CT3) < 4.0 allows for a reasonable distribution of the thickness of each component inside the lens barrel, which is beneficial for lens assembly and improves lens reliability. Furthermore, it facilitates control of the radius of curvature of the third lens, enabling control of the light emission angle of the third lens.

[0061] In an exemplary embodiment, the optical system of this application satisfies: 3.0 < |R1+R2| / (EP01+CT1)) < 19.0, where R1 is the radius of curvature of the first side surface of the first lens, R2 is the radius of curvature of the second side surface of the first lens, EP01 is the distance along the optical axis between the front end face of the lens barrel and the first side surface of the first spacer, and CT1 is the center thickness of the first lens along the optical axis. Satisfying 3.0 < |R1+R2| / (EP01+CT1)) < 19.0 is beneficial for controlling the radius of curvature of the first lens, ensuring the thickness ratio of the first lens, and further improving the stability of the first lens forming.

[0062] In an exemplary embodiment, the optical system of this application satisfies: 1.0 < |R1| / d0s < 4.0, where R1 is the radius of curvature of the first side surface of the first lens, and d0s is the inner diameter of the front end face of the lens barrel. Satisfying 1.0 < |R1| / d0s < 4.0 limits the maximum external shape of the lens barrel, which is beneficial for achieving a compact lens structure. At the same time, controlling the radius of curvature of the first side surface of the first lens is beneficial for correcting off-axis aberrations and improving the overall image quality of the system.

[0063] In an exemplary embodiment, the optical system of this application satisfies: 1.5 < |CP2×f2 / (CP1×f1)| < 7500.0, where CP1 is the maximum thickness of the first spacer along the optical axis, CP2 is the maximum thickness of the second spacer along the optical axis, f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens. Satisfying 1.5 < |CP2×f2 / (CP1×f1)| < 7500.0, by controlling the effective focal lengths of the first and second lenses, is beneficial for correcting system aberrations; simultaneously, by controlling the thicknesses of the first and second spacers, it facilitates the assembly of the first and second lenses, reducing deformation after the lenses and spacers are assembled.

[0064] In an exemplary embodiment, the first and second sides of the quarter-wave plate have the same radius of curvature. The optical system of this application satisfies: 1.0 < D0m / |R6| < 2.5, where D0m is the outer diameter of the rear end face of the lens barrel, and R6 is the radius of curvature of the second side of the third lens. By satisfying 1.0 < D0m / |R6| < 2.5 and controlling the radius of curvature of the optical system, the field of view of the system is effectively constrained, thereby enabling the system to meet the characteristics of a large field of view. At the same time, limiting the outer diameter of the rear end face of the lens barrel constrains the external dimensions of the lens barrel, minimizing its external dimensions while ensuring its manufacturability, thereby reducing the overall size of the device.

[0065] In an exemplary embodiment, the optical system of this application satisfies: 0.01 < (f1 + f3) / |f2| < 2.5, where f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, and f3 is the effective focal length of the third lens. Satisfying 0.01 < (f1 + f3) / |f2| < 2.5, by controlling the focal lengths of the first, second, and third lenses, makes the second lens flatter and the first and third lenses more curved. This helps reduce the impact of the first lens structure on the overall length of the optical system, and also facilitates the control of the light emission angle by the third lens. Controlling the effective focal lengths of the three lenses allows for a reasonable allocation of optical power, reversing the light path and shortening the length of the optical system. It also helps correct system aberrations and improves system performance.

[0066] In an exemplary embodiment, the optical system of this application satisfies: 3.5 < L / ∑CT + L / ∑AT < 7.5, where L is the maximum height of the lens barrel along the optical axis, ∑CT is the sum of the center thicknesses of the first to third lenses along the optical axis, and ∑AT is the sum of the air gaps between any two adjacent lenses among the first to third lenses along the optical axis. Satisfying 3.5 < L / ∑CT + L / ∑AT < 7.5 is beneficial for miniaturization and ensures the overall appearance of the optical system.

[0067] In an exemplary embodiment, the first lens may have positive optical power, the second lens may have positive or negative optical power, and the third lens may have positive or negative optical power. Appropriately matching the optical powers of each lens is beneficial for correcting system aberrations.

[0068] In an exemplary embodiment, the optical system of this application may include at least one aperture stop. The aperture stop can constrain the optical path and control the light intensity. The aperture stop can be positioned at an appropriate location within the optical system; for example, the aperture stop can be located on a first side of the first lens.

[0069] In an exemplary embodiment, the effective focal length f1 of the first lens may be in the range of 56.0 mm to 2308.0 mm, the effective focal length f2 of the second lens may be in the range of -85.0 mm to 290000.0 mm, and the effective focal length f3 of the third lens may be in the range of -400.0 mm to 125.0 mm.

[0070] According to some embodiments of this application, the optical system of this application is a small-volume optical system with high-definition imaging quality. In application, the optical system according to exemplary embodiments of this application can be applied to VR devices. By reasonably setting the effective focal length, maximum field of view, entrance pupil diameter, and lens parameters such as center thickness, refractive index, Abbe number, and radius of curvature of the optical system, and by reasonably setting the aperture stop parameters, the wide-angle purpose of the VR device can be met, as well as the chromatic aberration of the system can be corrected, thereby improving the system's imaging quality. By setting spacers between lenses, the lens processing and forming performance can be improved, the lens sensitivity can be reduced, the assembly yield can be increased, and the miniaturization goal of VR equipment can be met while ensuring the performance of the optical system.

[0071] Specific embodiments of the optical system applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

[0072] Example 1

[0073] The following is for reference Figures 3A to 4C The optical system according to Embodiment 1 of this application is described. Figures 3A to 3D A schematic diagram of the structure of an optical system according to four embodiments of Embodiment 1 of this application is shown.

[0074] like Figures 3A to 3DAs shown, the optical system sequentially includes, from the first side to the second side along the optical axis: a lens barrel, and a lens assembly, a reflection assembly, and a spacer assembly disposed within the lens barrel. The lens assembly includes a first lens E1, a second lens E2, and a third lens E3. The reflection assembly may include a reflective polarizing element (not shown), a quarter-wave plate (not shown), disposed on the second side of the second lens, and a partially reflective layer (not shown), disposed on the second side of the third lens. Exemplarily, the reflective polarizing element and the quarter-wave plate may be combined and attached to the second side of the second lens.

[0075] Table 1 shows the basic parameters of the optical system of Embodiment 1, where the units for radius of curvature and thickness are millimeters (mm). Table 1 only lists, by way of example, the correspondence between surface numbers and some components. Due to the shared surfaces between adjacent components, it is inconvenient to label all components at the locations of shared surfaces in Table 1. For example, S4 is the second side surface of the second lens and also the first side surface of the reflective polarizing element; S6 is the second side surface of the third lens and also the first side surface of the partial reflective layer. For simplicity, the thicknesses of the reflective polarizing element, quarter-wave plate, and partial reflective layer are not specifically shown in Table 1.

[0076]

[0077] Table 1

[0078] Referring to Table 1, the optical system may further include an emitting unit disposed on the second side of the third lens. The light emitted by the emitting unit passes through the third lens E3 and reaches the reflective polarizing element disposed on the second side S4 of the second lens E2. It is reflected by the reflective polarizing element and passes through the third lens E3 again. Subsequently, the light beam is reflected again at a partial reflective layer on the second side S6 of the third lens E3, and passes through the third lens E3, the reflective polarizing element, the second lens E2 and the first lens E1 in sequence. After passing through the aperture STO, it is finally received by the receiving unit, which may be, for example, a human eye.

[0079] In Embodiment 1, the first and second side surfaces of any one of the first lens E1 to the third lens E3 are aspherical surfaces, and the surface shape x of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0080]

[0081] Where x is the distance vector from the vertex of the aspherical surface at a height h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 2 gives the conic coefficients and higher-order coefficients A4, A6, A8 and A6 that can be used for each aspherical mirror S1-S6 in Example 1. 10 .

[0082] Face number Conic coefficient A4 A6 A8 A10 S1 0.0000 2.97E-01 -6.33E-02 -1.49E-02 3.58E-02 S2 0.0000 -5.33E-01 4.12E-02 -1.69E-02 2.49E-03 S3 0.0000 -1.12E+00 2.83E-01 -8.92E-02 1.23E-02 S4 0.0000 -4.36E-01 1.04E-01 -3.58E-02 1.48E-02 S5 0.0000 -1.28E-01 -4.76E-02 -8.96E-03 6.12E-03 S6 0.0000 5.26E-02 6.79E-02 -1.53E-02 1.83E-03

[0083] Table 2

[0084] In this example, the maximum half field of view (HFOV) of the optical system is 30.0°, the effective focal length of the first lens is 71.65 mm, the effective focal length of the second lens is -84.70 mm, and the effective focal length of the third lens is 124.37 mm.

[0085] like Figure 3A and Figure 3C The optical system shown includes a first spacer P1 and a second spacer P2, as follows: Figure 3B and Figure 3D The optical system shown includes a first spacer P1. The first spacer P1 is disposed between the first lens and the second lens and is in contact with the first lens. The second spacer P2 is disposed between the second lens and the third lens and is in contact with the second lens.

[0086] Table 3 provides the basic parameters of the lens barrel and spacer of the optical system under the four implementation methods in Example 1. The unit of each parameter in Table 3 is millimeters (mm).

[0087] Parameter name Implementation 1 Implementation 2 Implementation 3 Implementation 4 D1s 35.521 35.579 28.849 28.849 d1s 25.740 25.951 22.639 22.639 EP01 5.374 5.374 6.410 6.410 D1m 35.521 35.579 29.926 29.926 d1m 25.740 25.951 24.100 24.100 EP12 4.600 / 5.051 / CP2 4.248 / 2.565 / D2s 36.224 / 33.335 / d2s 32.015 / 28.125 / D2m 37.518 / 34.412 / d2m 34.693 / 29.586 / d0m 44.118 44.118 42.244 42.244 d0s 26.962 26.962 21.304 21.304 CP1 0.050 0.050 1.757 1.757 D0m 49.118 49.118 46.244 46.244 L 19.740 19.740 22.400 22.400

[0088] Table 3

[0089] Figure 4A The on-axis chromatic aberration curve of the optical system of Embodiment 1 is shown, which represents the deviation of light of different wavelengths from the convergence focal point after passing through the lens. Figure 4B The astigmatism curves of the optical system of Embodiment 1 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 4C The distortion curves of the optical system of Example 1 are shown, representing the distortion magnitude values ​​corresponding to different half-field angles. According to... Figures 4A to 4C It can be seen that the optical system given in Example 1 can achieve good imaging quality.

[0090] Example 2

[0091] The following is for reference Figures 5A to 6CAn optical system according to Embodiment 2 of this application is described. In this embodiment and the following embodiments, for the sake of brevity, descriptions similar to those in Embodiment 1 will be omitted. Figure 5A and Figure 5B A schematic diagram of the structure of the optical system according to two embodiments of Embodiment 2 of this application is shown.

[0092] like Figure 5A and Figure 5B As shown, the optical system sequentially includes, from the first side to the second side along the optical axis: a lens barrel, and a lens assembly, a reflection assembly, and a spacer assembly disposed within the lens barrel. The lens assembly includes a first lens E1, a second lens E2, and a third lens E3. The reflection assembly may include a reflective polarizing element (not shown), a quarter-wave plate (not shown), disposed on the second side of the second lens, and a partially reflective layer (not shown), disposed on the second side of the third lens. Exemplarily, the reflective polarizing element and the quarter-wave plate may be combined and attached to the second side of the second lens.

[0093] 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 shared surface issues between adjacent components, it is inconvenient to label all components at the locations of shared surfaces in Table 4. For example, S4 is the second side surface of the second lens and also the first side surface of the reflective polarizing element; S6 is the second side surface of the third lens and also the first side surface of the partial reflective layer. For simplicity, the thicknesses of the reflective polarizing element, quarter-wave plate, and partial reflective layer are not specifically shown in Table 4. Table 5 shows the conic coefficients and higher-order coefficients that can be used for each aspherical mirror surface in Embodiment 2, where each aspherical surface shape can be defined by formula (1) given in Embodiment 1 above.

[0094]

[0095] Table 4

[0096] Face number Conic coefficient A4 A6 A8 A10 S1 0.0000 -1.67E+00 -1.78E-01 -4.30E-02 -1.30E-03 S2 0.0000 -2.29E+00 -2.27E-01 -6.64E-02 -1.37E-03 S3 0.0000 -1.64E+00 -2.92E-01 -1.50E-01 -1.02E-02 S4 0.0000 -9.10E-01 -3.10E-01 -1.01E-01 8.55E-03 S5 0.0000 7.47E-01 -6.59E-02 1.26E-02 1.49E-02 S6 0.0000 4.83E-03 -4.03E-02 -2.54E-02 -1.77E-03

[0097] Table 5

[0098] Referring to Table 4, the optical system may further include an emitting unit disposed on the second side of the third lens. The light emitted by the emitting unit passes through the third lens E3 and reaches the reflective polarizing element disposed on the second side S4 of the second lens E2. It is reflected by the reflective polarizing element and passes through the third lens E3 again. Subsequently, the light beam is reflected again at a partial reflective layer on the second side S6 of the third lens E3, and passes through the third lens E3, the reflective polarizing element, the second lens E2 and the first lens E1 in sequence. After passing through the aperture STO, it is finally received by the receiving unit, which may be, for example, a human eye.

[0099] In this example, the maximum half field of view (HFOV) of the optical system is 30.0°, the effective focal length of the first lens is 2307.29 mm, the effective focal length of the second lens is 280748.65 mm, and the effective focal length of the third lens is -399.58 mm.

[0100] like Figure 5A and Figure 5B The optical system shown includes a first spacer P1 and a second spacer P2. The first spacer P1 is disposed between the first lens and the second lens and is in contact with the first lens. The second spacer P2 is disposed between the second lens and the third lens and is in contact with the second lens.

[0101] Table 6 provides the basic parameters of the lens barrel and spacer of the optical system under the two implementation methods in Example 2. The unit of each parameter in Table 6 is millimeters (mm).

[0102] Parameter name Implementation 1 Implementation 2 D1s 35.495 35.495 d1s 27.574 27.574 EP01 10.232 10.232 D1m 35.495 35.495 d1m 27.574 27.574 EP12 5.017 2.178 CP2 0.050 2.939 D2s 42.419 36.123 d2s 34.310 31.913 D2m 42.419 38.111 d2m 34.310 35.088 d0m 46.831 46.831 d0s 19.481 19.481 CP1 0.050 0.050 D0m 50.831 50.831 L 22.720 22.720

[0103] Table 6

[0104] Figure 6A 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 6B 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 6C 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 6A to 6C It can be seen that the optical system given in Example 2 can achieve good imaging quality.

[0105] Example 3

[0106] The following is for reference Figures 7A to 8C An optical system according to Embodiment 3 of this application is described. Figure 7A and Figure 7B A schematic diagram of the structure of the optical system according to two embodiments of Embodiment 3 of this application is shown.

[0107] like Figure 7A and Figure 7BAs shown, the optical system sequentially includes, from the first side to the second side along the optical axis: a lens barrel, and a lens assembly, a reflection assembly, and a spacer assembly disposed within the lens barrel. The lens assembly includes a first lens E1, a second lens E2, and a third lens E3. The reflection assembly may include a reflective polarizing element (not shown), a quarter-wave plate (not shown), disposed on the second side of the second lens, and a partially reflective layer (not shown), disposed on the second side of the third lens. Exemplarily, the reflective polarizing element and the quarter-wave plate may be combined and attached to the second side of the second lens.

[0108] Table 7 shows the basic parameters of the optical system of Embodiment 3, where the units for radius of curvature and thickness are millimeters (mm). Table 7 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 label all components at the locations of shared surfaces in Table 7. For example, S4 is the second side surface of the second lens and also the first side surface of the reflective polarizing element; S6 is the second side surface of the third lens and also the first side surface of the partial reflective layer. For simplicity, the thicknesses of the reflective polarizing element, quarter-wave plate, and partial reflective layer are not specifically shown in Table 8. Table 8 shows the conic coefficients and higher-order coefficients that can be used for each aspherical mirror surface in Embodiment 3, where each aspherical surface shape can be defined by formula (1) given in Embodiment 1 above.

[0109]

[0110] Table 7

[0111] Face number Conic coefficient A4 A6 A8 A10 S1 0.0000 -9.68E-01 7.26E-02 5.54E-02 -1.34E-02 S2 0.0000 -1.27E+00 2.27E-01 -1.23E-02 1.01E-02 S3 0.0000 -1.01E+00 2.51E-01 -1.49E-01 6.31E-02 S4 0.0000 -5.00E-01 5.41E-02 -9.34E-03 2.49E-02 S5 0.0000 -6.93E-01 2.07E-02 2.60E-02 1.60E-02 S6 0.0000 -3.14E-01 2.26E-03 -1.65E-02 1.31E-02

[0112] Table 8

[0113] Referring to Table 7, the optical system may further include an emitting unit disposed on the second side of the third lens. The light emitted by the emitting unit passes through the third lens E3 and reaches the reflective polarizing element disposed on the second side S4 of the second lens E2. It is reflected by the reflective polarizing element and passes through the third lens E3 again. Subsequently, the light beam is reflected again at a partial reflective layer on the second side S6 of the third lens E3, and passes through the third lens E3, the reflective polarizing element, the second lens E2 and the first lens E1 in sequence. After passing through the aperture STO, it is finally received by the receiving unit, which may be, for example, a human eye.

[0114] In this example, the maximum half field of view (HFOV) of the optical system is 30.0°, the effective focal length of the first lens is 56.48 mm, the effective focal length of the second lens is -75.99 mm, and the effective focal length of the third lens is 102.22 mm.

[0115] like Figure 7AThe optical system shown includes a first spacer P1 and a second spacer P2, as follows: Figure 7B The optical system shown includes a first spacer P1, which is disposed between the first lens and the second lens and is in contact with the first lens, and a second spacer P2, which is disposed between the second lens and the third lens and is in contact with the second lens.

[0116] Table 9 provides the basic parameters of the lens barrel and spacer of the optical system under the two implementation methods in Example 3. The unit of each parameter in Table 9 is millimeters (mm).

[0117] Parameter name Implementation 1 Implementation 2 D1s 33.464 33.464 d1s 24.162 24.162 EP01 5.382 5.382 D1m 33.464 33.464 d1m 24.162 24.162 EP12 4.452 / CP2 2.869 / D2s 33.085 / d2s 28.876 / D2m 35.921 / d2m 33.096 / d0m 41.888 41.888 d0s 23.752 23.752 CP1 0.050 0.050 D0m 45.888 45.888 L 19.176 19.176

[0118] Table 9

[0119] Figure 8A The on-axis chromatic aberration curve of the optical system of Embodiment 3 is shown, which represents the deviation of light of different wavelengths from the convergence focal point after passing through the lens. Figure 8B The astigmatism curves of the optical system of Embodiment 3 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 8C The distortion curves of the optical system in Example 3 are shown, representing the distortion magnitudes corresponding to different half-field angles. According to... Figures 8A to 8C It can be seen that the optical system given in Example 3 can achieve good imaging quality.

[0120] In summary, the relationships of the optical systems in Examples 1 to 3 are shown in Table 10.

[0121]

[0122]

[0123] Table 10

[0124] This application also provides an optical device, which can be a stand-alone projection device such as a projector, or a projection module integrated into a mobile electronic device such as a VR device. The optical device is equipped with the optical system described above.

[0125] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of protection involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the concept of this application. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An optical system, characterized in that, include: The lens barrel and the lens assembly, reflection assembly, and spacer assembly disposed within the lens barrel, wherein, The lens assembly includes, in sequence from the first side to the second side along the optical axis: a first lens, a second lens, and a third lens; The spacer assembly includes at least one spacer element disposed between two adjacent lenses in the lens assembly; The lens barrel has a front end face facing the first side and a rear end face facing the second side, wherein the maximum outer diameter of the front end face is smaller than the maximum outer diameter of the rear end face; and The inner diameter d0m of the rear end face of the lens barrel, the maximum half field of view HFOV of the optical system, and the maximum height L of the lens barrel along the optical axis satisfy: 1.09≤tan(HFOV)×d0m / L≤1.29; The effective focal length f1 of the first lens, the effective focal length f2 of the second lens, and the effective focal length f3 of the third lens satisfy: 0.01 < (f1 + f3) / |f2| ≤ 2.31; The first lens has positive optical power; The second lens and the third lens have opposite positive and negative optical power properties; The first side surfaces of both the second lens and the third lens are concave, and the second side surfaces are both convex. The optical system has three lenses with optical power. The reflective assembly includes a reflective polarizing element, a quarter-wave plate, and a partial reflective layer, wherein the reflective polarizing element and the quarter-wave plate are disposed on the second side of the second lens, and the partial reflective layer is disposed on the second side of the third lens.

2. The optical system according to claim 1, characterized in that, The spacer assembly includes a first spacer disposed between the first lens and the second lens and in contact with the first lens; wherein... The radius of curvature R2 of the second side of the first lens, the outer diameter D1s of the first side of the first spacer and the inner diameter d1s of the first side of the first spacer satisfy: 3.92≤|R2| / (D1s-d1s)≤17.

40.

3. The optical system according to claim 1, characterized in that, The spacer assembly includes a first spacer disposed between the first lens and the second lens and in contact with the first lens; wherein... The radius of curvature R3 of the first side of the second lens, the outer diameter D1m of the second side of the first spacer and the inner diameter d1m of the second side of the first spacer satisfy: -4.61≤R3 / (D1m-d1m)≤-2.

55.

4. The optical system according to claim 1, characterized in that, The spacing component includes: A first spacer is disposed between the first lens and the second lens and is in contact with the first lens; and A second spacer is disposed between the second lens and the third lens and is in contact with the second lens; wherein... The combined focal length f12 of the first lens and the second lens, the center thickness CT1 of the first lens on the optical axis, the center thickness CT2 of the second lens on the optical axis, and the spacing EP12 between the first spacer and the second spacer along the optical axis satisfy: 17.11≤f12 / (CT1+CT2+EP12)≤334.

41.

5. The optical system according to claim 1, characterized in that, The spacer assembly includes a second spacer disposed between the second lens and the third lens and in contact with the second lens; wherein... The outer diameter D2s of the first side of the second spacer, the inner diameter d2s of the first side of the second spacer, and the radius of curvature R4 of the second side of the second lens satisfy: 0.66≤(D2s+d2s) / |R4|≤3.

62.

6. The optical system according to claim 1, characterized in that, The spacer assembly includes a second spacer disposed between the second lens and the third lens and in contact with the second lens; wherein... The effective focal length f3 of the third lens, the maximum thickness CP2 of the second spacer along the optical axis, and the air gap T23 between the second lens and the third lens on the optical axis satisfy: 17.96≤|f3| / (CP2+T23)≤91.

45.

7. The optical system according to claim 1, characterized in that, The spacer assembly includes a second spacer disposed between the second lens and the third lens and in contact with the second lens; wherein... The outer diameter D2s of the first side of the second spacer, the outer diameter D2m of the second side of the second spacer, and the radius of curvature R5 of the first side of the third lens satisfy: 0.3<(D2s+D2m) / |R5|≤4.

29.

8. The optical system according to claim 1, characterized in that, The spacer assembly includes a second spacer disposed between the second lens and the third lens and in contact with the second lens; wherein... The radius of curvature R6 of the second side of the third lens, the maximum thickness CP2 of the second spacer along the optical axis, and the center thickness CT3 of the third lens on the optical axis satisfy: 2.61≤|R6| / (EP12+CP2+CT3)≤3.

72.

9. The optical system according to claim 1, characterized in that, The spacer assembly includes a first spacer disposed between the first lens and the second lens and in contact with the first lens; wherein... The radius of curvature R1 of the first side surface of the first lens, the radius of curvature R2 of the second side surface of the first lens, the distance EP01 between the front end surface of the lens barrel and the first side surface of the first spacer along the optical axis, and the center thickness CT1 of the first lens on the optical axis satisfy: 3.70≤|R1+R2| / (EP01+CT1)≤13.

40.

10. The optical system according to any one of claims 1 to 9, characterized in that, The radius of curvature R1 of the first side surface of the first lens and the inner diameter d0s of the front end face of the lens barrel satisfy: 1.08≤|R1| / d0s≤3.

62.

11. The optical system according to claim 1, characterized in that, The spacing component includes: A first spacer is disposed between the first lens and the second lens and is in contact with the first lens; and A second spacer is disposed between the second lens and the third lens and is in contact with the second lens; wherein... The maximum thickness CP1 of the first spacer along the optical axis, the maximum thickness CP2 of the second spacer along the optical axis, the effective focal length f1 of the first lens, and the effective focal length f2 of the second lens satisfy the following: 1.73≤|CP2×f2 / (CP1×f1)|≤7152.

04.

12. The optical system according to any one of claims 1 to 9, characterized in that, The outer diameter D0m of the rear end face of the lens barrel and the radius of curvature R6 of the second side face of the third lens satisfy the following condition: 1.0 < D0m / |R6| ≤ 2.

24.

13. The optical system according to any one of claims 1 to 9, characterized in that, The maximum height L of the lens barrel along the optical axis, the sum of the center thicknesses of the first lens to the third lens on the optical axis ∑CT, and the sum of the air gaps on the optical axis between any two adjacent lenses among the first lens to the third lens ∑AT satisfy: 4.05≤L / ∑CT+L / ∑AT≤6.

77.

14. An optical device, characterized in that, Includes the optical system as described in any one of claims 1 to 13.

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