Optical system

Abstract

The utility model discloses an optical system, the optical system comprises a lens barrel, and a lens group and a spacing element group which are arranged in the lens barrel, and the lens group sequentially comprises a first lens with negative focal power, a second lens with negative focal power, a third lens with negative focal power and a fourth lens with negative focal power from an object side to an image side along an optical axis; the second lens has positive focal power; the third lens has positive focal power; the fourth lens has positive focal power; the maximum field angle FOV of the optical system and the maximum length L of the lens barrel in the optical axis direction meet the following conditions: 5.6 lt; tan (FOV / 2) * Llt; 7.85); the effective focal length f of the optical system, the outer diameter D0m of the image-side end face of the lens barrel and the outer diameter D0s of the object-side end face of the lens barrel satisfy 0.5 lt; f / (D0m-D0s) lt; and 1.3.

Description

Technical Field

[0001] This application relates to the field of optical elements, and specifically, to an optical system. Background Art

[0002] With the progress of technology, consumer electronics products such as mobile phones, VR headsets, and drones are updated very rapidly, and the industry scale also increases accordingly. The application of optical lenses in the field of consumer electronics is becoming more and more extensive. Consumer electronics products often obtain spatial information, take photos and videos through optical lenses. For example, our smartphones can take high-quality photos and videos, and our VR headsets can present an excellent visual experience, etc. These are all inseparable from optical lenses. Therefore, in order to meet the application requirements in the field of consumer electronics, optical lenses also need to continue to expand and innovate. The present invention relates to an optical system composed of four lenses, which has the characteristics of a large field angle and broad application prospects. Summary of the Utility Model

[0003] In the first aspect of this application, such an optical system is provided. The optical system includes: a lens barrel and a lens group placed in the lens barrel. Among them, the lens group includes, in order from the object side to the image side along the optical axis: a first lens with a negative optical power; a second lens with a positive optical power; a third lens with a positive optical power; and a fourth lens with a positive optical power. The maximum field angle FOV of the optical system and the maximum length L of the lens barrel along the optical axis satisfy: 5.6<Tan(FOV / 2)×L<7.85; the effective focal length f of the optical system, the outer diameter D0m of the image-side end face of the lens barrel, and the outer diameter D0s of the object-side end face of the lens barrel satisfy: 0.5<f / (D0m-D0s)<1.3.

[0004] In one embodiment, the optical system further includes a first spacer element placed on the image side of the first lens and at least partially contacting the image side face of the first lens. The optical system satisfies: 3.1<(D1s-d1m) / (f1+f2)<5.65, where D1s is the outer diameter of the object side face of the first spacer element, d1m is the inner diameter of the image side face of the first spacer element, f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens.

[0005] In one embodiment, the optical system further includes a third spacer element placed on the image side of the third lens and at least partially contacting the image side face of the third lens. There is an air gap on the optical axis between any two adjacent lenses among the first lens to the fourth lens, and the air gap on the optical axis between the third lens and the fourth lens is the smallest. The optical system satisfies: 0.13<CP3 / T34<8.6, where CP3 is the maximum thickness of the third spacer element along the optical axis, R3 is the curvature radius of the object side face of the second lens, and T34 is the air gap on the optical axis between the third lens and the fourth lens.

[0006] In one embodiment, the optical system further includes a first spacer element and a second spacer element. The first spacer element is disposed on the image side of the first lens and at least partially contacts the image-side surface of the first lens. The second spacer element is disposed on the image side of the second lens and at least partially contacts the image-side surface of the second lens. The optical system satisfies: 0.75 < R2 / R3 < 1.1 and -6.1 < f12 / EP12 < -2.2, where R2 is the radius of curvature of the image-side surface of the first lens, R3 is the radius of curvature of the object-side surface of the second lens, f12 is the combined focal length of the first lens and the second lens, and EP12 is the distance between the first spacer element and the second spacer element along the optical axis.

[0007] In one embodiment, the optical system further includes a first spacer element and a second spacer element. The first spacer element is disposed on the image side of the first lens and at least partially contacts the image-side surface of the first lens. The second spacer element is disposed on the image side of the second lens and at least partially contacts the image-side surface of the second lens. The optical system satisfies: 0.82 < (D1m - d1m) / (D2m - d2m) < 1.26, where D1m is the outer diameter of the image-side surface of the first spacer element, d1m is the inner diameter of the image-side surface of the first spacer element, D2m is the outer diameter of the image-side surface of the second spacer element, and d2m is the inner diameter of the image-side surface of the second spacer element.

[0008] In one embodiment, the optical system further includes a first spacer element and a second spacer element. The first spacer element is disposed on the image side of the first lens and at least partially contacts the image-side surface of the first lens. The second spacer element is disposed on the image side of the second lens and at least partially contacts the image-side surface of the second lens. The optical system satisfies: 2.4 < T12 / (CP1 + CP2) < 7.1, where T12 is the air gap between the first lens and the second lens on the optical axis, CP1 is the maximum thickness of the first spacer element along the optical axis, and CP2 is the maximum thickness of the second spacer element along the optical axis.

[0009] In one embodiment, the optical system further includes a first spacer element disposed on the image side of the first lens and at least partially contacting the image-side surface of the first lens. The optical system satisfies: 3.2 < (d0s - d1s) / (DT11 - DT12) < 4.0, where d0s is the inner diameter of the object-side end face of the lens barrel, d1s is the inner diameter of the object-side surface of the first spacer element, DT11 is the diameter of the light-transmitting portion of the object-side surface of the first lens, and DT12 is the diameter of the light-transmitting portion of the image-side surface of the first lens.

[0010] In one embodiment, the optical system further includes a third spacer element disposed on the image side of the third lens and at least partially contacting the image side surface of the third lens; the optical system satisfies: -2.8 < R5 / R6 < -1.65 and 1.2 < f3 / d3s < 1.6, where R5 is the radius of curvature of the object side surface of the third lens, R6 is the radius of curvature of the image side surface of the third lens, f3 is the effective focal length of the third lens, and d3s is the inner diameter of the object side surface of the third spacer element.

[0011] In one embodiment, the optical system further includes a third spacer element disposed on the image side of the third lens and at least partially contacting the image side surface of the third lens; the optical system satisfies: 0.8 < f4 / (D3m - d3m) < 2.6, where f4 is the effective focal length of the fourth lens, D3m is the outer diameter of the image side surface of the third spacer element, and d3m is the inner diameter of the image side surface of the third spacer element.

[0012] In one embodiment, the optical system satisfies: 1.95 < DT11 / (D0s - d0s) < 2.8, where DT11 is the diameter of the light-transmitting portion of the object side surface of the first lens, D0s is the outer diameter of the object side end surface of the lens barrel, and d0s is the inner diameter of the object side end surface of the lens barrel.

[0013] In one embodiment, the optical system further includes a second spacer element and a third spacer element. The second spacer element is disposed on the image side of the second lens and at least partially contacts the image side surface of the second lens, and the third spacer element is disposed on the image side of the third lens and at least partially contacts the image side surface of the third lens; the optical system satisfies: 0.8 < CT3 / EP23 < 1.35 and 1.0 ≤ CT3 / CT4 < 1.35, where EP23 is the axial spacing distance between the second spacer element and the third spacer element, CT3 is the central thickness of the third lens on the optical axis, and CT4 is the central thickness of the fourth lens on the optical axis.

[0014] In one embodiment, the optical system further includes a first spacer element, a second spacer element, and a third spacer element. The first spacer element is disposed on the image side of the first lens and at least partially contacts the image side surface of the first lens, the second spacer element is disposed on the image side of the second lens and at least partially contacts the image side surface of the second lens, and the third spacer element is disposed on the image side of the third lens and at least partially contacts the image side surface of the third lens; the optical system satisfies: 0.9 < f23 / (EP12 + EP23) < 1.2, where f23 is the combined focal length of the second lens and the third lens, EP12 is the axial spacing distance between the first spacer element and the second spacer element, and EP23 is the axial spacing distance between the second spacer element and the third spacer element.

[0015] In one embodiment, the optical system further includes a first spacer element and a second spacer element. The first spacer element is disposed on the image side of the first lens and at least partially contacts the image side surface of the first lens. The second spacer element is disposed on the image side of the second lens and at least partially contacts the image side surface of the second lens. Among the first lens to the fourth lens, the second lens has the largest central thickness on the optical axis. The optical system satisfies: 1.2 < CT2 / CT3 < 2.3 and 1.1 < CT2 / EP12 < 1.35, where CT2 is the central thickness of the second lens on the optical axis, CT3 is the central thickness of the third lens on the optical axis, and EP12 is the axial spacing distance between the first spacer element and the second spacer element.

[0016] In one embodiment, the object side surface of the first lens is concave, and the image side surface is concave; the object side surface of the second lens is convex, and the image side surface is concave; the object side surface of the third lens is convex, and the image side surface is convex; the object side surface of the fourth lens is convex, and the image side surface is concave.

[0017] In a second aspect of the present application, there is provided such an optical system, which includes a lens barrel and a lens group disposed in the lens barrel. The lens group includes, in order from the object side to the image side along the optical axis: a first lens with a negative optical power, a second lens with a positive optical power, a third lens with a positive optical power, and a fourth lens with a positive optical power. The optical system further includes a first spacer element and a second spacer element. The first spacer element is disposed on the image side of the first lens and at least partially contacts the image side surface of the first lens. The second spacer element is disposed on the image side of the second lens and at least partially contacts the image side surface of the second lens. The optical system satisfies: 1.2 < CT2 / CT3 < 2.3 and 1.1 < CT2 / EP12 < 1.35, where CT2 is the central thickness of the second lens on the optical axis, CT3 is the central thickness of the third lens on the optical axis, and EP12 is the axial spacing distance between the first spacer element and the second spacer element.

[0018] The present application provides a four-piece optical system, in which the maximum field of view angle FOV and the maximum length L of the lens barrel along the optical axis satisfy: 5.6 < Tan(FOV / 2) × L < 7.85. When the optical system satisfies the ultra-wide angle, it is easy to cause the overall length of the lens barrel to be too long, resulting in the phenomenon of darkening at the imaging edge, thus affecting the imaging brightness of the lens. By limiting the optical power of each lens, controlling the relationship between the effective focal length f of the optical system and the outer diameters of the image side end face and the object side end face of the lens barrel, and satisfying 0.5 < f / (D0m - D0s) < 1.3, the overall length of the lens barrel and the apertures of the object side end face and the image side end face can be effectively controlled, so that the aperture difference of the lens is within a reasonable range, thereby improving the light input of the lens and ensuring the imaging performance of the lens. Description of the Drawings

[0019] Other features, objects and advantages of the present application will become more apparent upon reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0020] Figure 1 A schematic diagram showing the structural arrangement of an optical system and some parameters according to the present application is shown;

[0021] Figure 2A 1 shows a schematic structural diagram of an optical system according to Example 1 of the present application;

[0022] Figure 2B 1 shows a schematic structural diagram of an optical system according to Example 2 of the present application;

[0023] Figure 2C 1 shows a schematic structural diagram of an optical system according to Example 3 of the present application;

[0024] Figures 3A to 3C The axial chromatic aberration curve, astigmatism curve, and magnification chromatic aberration curve of the optical systems according to Examples 1 to 3 of the present application are respectively shown;

[0025] Figure 4A 1 shows a schematic structural diagram of an optical system according to Example 4 of the present application;

[0026] Figure 4B 1 shows a schematic structural diagram of an optical system according to Example 5 of the present application;

[0027] Figure 4C 1 shows a schematic structural diagram of an optical system according to Example 6 of the present application;

[0028] Figures 5A to 5C The axial chromatic aberration curve, astigmatism curve, and magnification chromatic aberration curve of the optical systems according to Examples 4 to 6 of the present application are respectively shown;

[0029] Figure 6A 1 shows a schematic structural diagram of an optical system according to Example 7 of the present application;

[0030] Figure 6B 1 shows a schematic structural diagram of an optical system according to Example 8 of the present application;

[0031] Figure 6C 1 shows a schematic structural diagram of an optical system according to Example 9 of the present application;

[0032] 7A to 7C The axial chromatic aberration curve, the astigmatism curve, and the magnification chromatic aberration curve of the optical systems according to Examples 7 to 9 of the present application are respectively shown. DETAILED DESCRIPTION

[0033] For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely descriptions of exemplary embodiments of the present application and are not intended to limit the scope of the present 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.

[0034] It should be noted that in this specification, the terms "first," "second," "third," etc., are used solely to distinguish one feature from another and do not limit the features. Thus, the first lens discussed below could also be referred to as the second lens or the third lens without departing from the teachings of this application.

[0035] In the drawings, the thickness, size, and shape of the lenses are slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical and aspherical surfaces shown in the drawings are provided by way of example. That is, the shapes of the spherical and aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0036] In this article, the paraxial region refers to the area near the optical axis. If a lens surface is convex and the location of the convex surface is undefined, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the location of the concave surface is undefined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0037] It should also be understood that the terms "comprises," "including," "having," "includes," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application." And, the term "exemplary" is intended to refer to an example or illustration.

[0038] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and will not be interpreted in an idealized or overly formal sense unless expressly defined as such herein.

[0039] It should be noted that, in the absence of any conflict, the embodiments and features of the embodiments in this application can be combined with each other. The following embodiments only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they should not be understood as limiting the scope of the patent of this application. It should be pointed out that for those skilled in the art, several variations and improvements can be made without departing from the concept of the present application, and these all fall within the scope of protection of this application. For example, the lens groups, lens barrels, and spacer elements in the various embodiments of the present application can be combined arbitrarily, and are not limited to the lens group in one embodiment being combined only with the lens barrel, spacer element, etc. of that embodiment.

[0040] The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments. Figure 1 The following diagram shows the structure of an optical system according to the present application and a schematic diagram of some parameters. It should be understood by those skilled in the art that some parameters of lenses commonly used in the art (such as the center thickness CT2 of the second lens on the optical axis) are not shown in the figure. Figure 1 As shown in Figure 1 Only some parameters of the lens barrel and the spacer element of an optical system of the present application are shown as examples to facilitate a better understanding of the present invention. Figure 1 As shown, D0s is the outer diameter of the object side end surface of the lens barrel, d0s is the inner diameter of the object side end surface of the lens barrel, D1s is the outer diameter of the object side surface of the first spacing element, d1s is the inner diameter of the object side surface of the first spacing element, d3s is the inner diameter of the object side surface of the third spacing element, D0m is the outer diameter of the image side surface of the lens barrel, D1m is the outer diameter of the image side surface of the first spacing element, d1m is the inner diameter of the image side surface of the first spacing element, D2m is the outer diameter of the image side surface of the second spacing element, and d2m is the inner diameter of the image side surface of the second spacing element , D3m is the outer diameter of the image side surface of the third spacer element, d3m is the inner diameter of the image side surface of the third spacer element, CP1 is the maximum thickness of the first spacer element along the optical axis, CP2 is the maximum thickness of the second spacer element along the optical axis, CP3 is the maximum thickness of the third spacer element along the optical axis, EP12 is the spacing distance between the first spacer element and the second spacer element along the optical axis, EP23 is the spacing distance between the second spacer element and the third spacer element along the optical axis, and L is the maximum length of the lens barrel along the optical axis.

[0041] An optical system according to an exemplary embodiment of the present application may include a lens barrel and a lens assembly disposed within the lens barrel. The lens assembly may include four lenses having optical power, namely a first lens, a second lens, a third lens, and a fourth lens. The four lenses are arranged in sequence along the optical axis from the object side to the image side. Any two adjacent lenses among the first to fourth lenses may be spaced apart by a distance.

[0042] In example embodiments, the first lens may have negative power, the second lens may have positive power, the third lens may have positive power, and the fourth lens may have positive power.

[0043] In an exemplary embodiment, the object-side surface of the first lens is concave and the image-side surface is concave; the object-side surface of the second lens is convex and the image-side surface is concave; the object-side surface of the third lens is convex and the image-side surface is convex; and the object-side surface of the fourth lens is convex and the image-side surface is concave.

[0044] In an exemplary embodiment, the optical system may include at least one of a first spacer element, a second spacer element, and a third spacer element. The first spacer element is positioned on the image side of the first lens and is in at least partial contact with the image side surface of the first lens. The second spacer element is positioned on the image side of the second lens and is in at least partial contact with the image side surface of the second lens. The third spacer element is positioned on the image side of the third lens and is in at least partial contact with the image side surface of the third lens.

[0045] It should be understood that this application does not specifically limit the number of spacer elements; any number of spacer elements may be included between any two lenses, and the entire optical system may also include any number of spacer elements. Spacer elements help the optical system intercept excess refractive and reflective light paths, reducing stray light and ghosting. Adding auxiliary support between the spacer element and the lens barrel can help alleviate problems such as poor assembly stability and low performance yield caused by large step differences between lenses.

[0046] In an exemplary embodiment, the number of spacer elements between the third and fourth lenses of the optical system is two, namely, a third spacer element and a third auxiliary spacer element. The third spacer element is at least partially in contact with the object-side surface of the third lens, and the third auxiliary spacer element is positioned on the image-side surface of the third spacer element and at least partially in contact with the third spacer element.

[0047] In an exemplary embodiment, the optical system may further include an aperture for limiting the light beam to further improve the imaging quality of the optical lens. For example, the aperture may be positioned between the second and third lenses. The aperture helps to narrow the light entering the optical lens, reducing the maximum aperture of the optical lens and lowering the system's assembly sensitivity. However, it should be noted that the aperture position disclosed herein is merely illustrative and not limiting; in alternative embodiments, the aperture may be positioned elsewhere as needed.

[0048] In an exemplary embodiment, the maximum field of view FOV of the optical system according to the present application and the maximum length L of the lens barrel along the optical axis satisfy: 5.6 <Tan(FOV / 2)×L<7.85。

[0049] In an exemplary embodiment, the effective focal length f of the optical system, the outer diameter D0m of the image-side end face of the lens barrel, and the outer diameter D0s of the object-side end face of the lens barrel satisfy: 0.5 < f / (D0m - D0s) < 1.3.

[0050] The optical system according to an exemplary embodiment of the present application includes: a lens barrel and a lens group disposed within the lens barrel. Among them, the lens group includes, in sequence from the object side to the image side along the optical axis: a first lens with a negative optical power, a second lens with a positive optical power, a third lens with a positive optical power, and a fourth lens with a positive optical power; the maximum field angle FOV of the optical system and the maximum length L of the lens barrel along the optical axis direction satisfy: 5.6 < Tan(FOV / 2) × L < 7.85. When the optical system meets the condition of an ultra-wide angle, it is likely to cause the overall length of the lens barrel to be too long, resulting in the darkening of the imaging edge, thus affecting the imaging brightness of the lens. By restricting the optical power of each lens, and controlling the relationship between the effective focal length f of the optical system and the outer diameters of the image-side end face and the object-side end face of the lens barrel, and satisfying 0.5 < f / (D0m - D0s) < 1.3, the overall length of the lens barrel and the apertures of the object-side end face and the image-side end face can be effectively controlled, so that the aperture difference of the lens is within a reasonable range, thereby improving the light input of the lens and ensuring the imaging performance of the lens.

[0051] The optical system according to an exemplary embodiment of the present application satisfies 5.6 < Tan(FOV / 2) × L < 7.85 and 0.5 < f / (D0m - D0s) < 1.3, ensuring the stability of the imaging performance of the overall lens. When dealing with mechanical reliability tests, the stress level distribution inside the lens is more uniform, and the deformation of the lens is smaller, so that the change amounts of the main evaluation indicators such as MTF, f, and FFL are smaller, and the failure risk is lower. Specifically, MTF (i.e., Modulation Transfer Function) represents the modulation transfer function, and MTF is a quantitative evaluation index for the optical performance of the lens, used to describe the efficiency of the transmitted light at different spatial frequencies. f represents the effective focal length of the optical imaging lens, and FFL represents the distance on the optical axis from the object side surface of the first lens to the imaging surface of the optical imaging lens. The beneficial effects of the above technical solutions of the present application will be further described below with reference to Table 1-1 and Table 1-2.

[0052] Tables 1-1 and 1-2 show the changes in f, FFL, and MTF at different fields of view for optical imaging lenses according to exemplary embodiments of the present application before and after two rounds of micro-drop testing. The changes are the differences between the pre- and post-test values. In Tables 1-1 and 1-2, negative numbers indicate a decrease in the post-test value compared to the pre-test value, while positive numbers indicate an increase in the post-test value. In Tables 1-1 and 1-2, the units for the changes in f and FFL are millimeters (mm), and the units for the change in MTF are %. More specifically, the MTF change is the change in MTF at a spatial frequency of 70 lp / mm. In Tables 1-1 and 1-2, S represents the sagittal direction, T represents the meridional direction, and the center, 0.3F, 0.5F, 0.7F, and 0.8F represent different fields of view, respectively.

[0053] Specifically, the micro-drop test can be, for example, a simulated mobile phone micro-drop test, and the test content can be set, for example: the drop height is 10 cm, the number of drops in each round is 500 times on each of the six sides, and 5000 times on the front and back sides, for a total of 13,000 times; two rounds of tests are stimulated with a total of 26,000 drops.

[0054] All data in Tables 1-1 and 1-2 are simulated data, not actual data. Furthermore, the three calibrated lens samples were not simulated to determine if the test environment had changed.

[0055] Analysis of the data in Tables 1-1 and 1-2 shows that the data for the 10 lens samples after the micro-drop test is essentially identical to the data for the three lens samples that were calibrated (without the micro-drop test). Before and after the two rounds of micro-drop tests, the MTF changes for the ten lenses were all within ±10%, and the changes in f and FFL were all within ±0.05mm, meeting design requirements. This demonstrates that the optical imaging lens of this application exhibited good stability and minimal internal lens deformation during the micro-drop test, resulting in minimal changes in key evaluation indicators such as MTF, f, and FFL, and a low risk of failure.

[0056]

[0057] Table 1-1

[0058]

[0059]

[0060] Table 1-2

[0061] In an exemplary embodiment, the optical system according to the present application may satisfy: 3.1 < (D1s - d1m) / (f1 + f2) < 5.65, where D1s is the outer diameter of the object side surface of the first spacer element, d1m is the inner diameter of the image side surface of the first spacer element, f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens. Satisfying 3.1 < (D1s - d1m) / (f1 + f2) < 5.65 limits the effective focal lengths of the first lens and the second lens, which can prevent the first lens and the second lens from having a large thickness ratio that affects the molding of the lens, is beneficial to improving the surface accuracy of the lens molding, and at the same time limits the outer diameter of the object side surface of the first spacer element and the inner diameter of the image side surface of the first spacer element, which is beneficial to limiting the lateral dimension of the lens head and avoiding the influence of stray light.

[0062] In an exemplary embodiment, the optical system according to the present application may satisfy: 0.13 < CP3 / T34 < 8.6, where CP3 is the maximum thickness of the third spacer element along the optical axis direction, R3 is the curvature radius of the object side surface of the second lens, and T34 is the air gap between the third lens and the fourth lens on the optical axis. Satisfying 0.13 < CP3 / T34 < 8.6 can control the thickness of the third spacer element within a reasonable range, ensure the stability of the molding of the third spacer element, and at the same time is beneficial to controlling the edge thicknesses of the third lens and the fourth lens, ensuring the processability of the lens, ensuring the stability of the surface shape of the lens after molding, and being beneficial to improving the quality of the lens.

[0063] In an exemplary embodiment, the optical system according to the present application may satisfy: 0.75 < R2 / R3 < 1.1 and -6.1 < f12 / EP12 < -2.2, where R2 is the curvature radius of the image side surface of the first lens, R3 is the curvature radius of the object side surface of the second lens, f12 is the combined focal length of the first lens and the second lens, and EP12 is the distance between the first spacer element and the second spacer element along the optical axis direction. Satisfying 0.75 < R2 / R3 < 1.1, by limiting the curvature radii of the image side surface of the first lens and the object side surface of the second lens, is beneficial to controlling the light to pass through along the required path when passing through the first lens to the second lens, ensuring the transmission of light; satisfying f12 / EP12, by controlling the distance between the first spacer element and the second spacer element along the optical axis direction, can effectively control the edge thickness of the second lens, ensuring the processability of the second lens; at the same time, controlling the combined focal length of the first lens and the second lens can ensure the structural stability of the first lens and the second lens, making the light refract along the required path.

[0064] In an exemplary embodiment, the optical system according to the present application may satisfy the following conditions: 0.82<(D1m-d1m) / (D2m-d2m)<1.26, wherein D1m is the outer diameter of the image side surface of the first spacer element, d1m is the inner diameter of the image side surface of the first spacer element, D2m is the outer diameter of the image side surface of the second spacer element, and d2m is the inner diameter of the image side surface of the second spacer element. Satisfying 0.82<(D1m-d1m) / (D2m-d2m)<1.26 can effectively control the difference between the inner and outer diameters of the first spacer element and the second spacer element, ensure the stability of the first lens and the second lens during the assembly process, reduce deformation during the assembly process, and improve the performance of the lens. At the same time, limiting the inner diameters of the first spacer element and the second spacer element can suppress stray light from the first lens and the second lens, thereby improving the imaging quality of the lens.

[0065] In an exemplary embodiment, the optical system according to the present application may satisfy the following: 2.4 < T12 / (CP1 + CP2) < 7.1, where T12 is the air spacing between the first and second lenses on the optical axis, CP1 is the maximum thickness of the first spacer element along the optical axis, and CP2 is the maximum thickness of the second spacer element along the optical axis. Satisfying 2.4 < T12 / (CP1 + CP2) < 7.1 and controlling the air spacing between the first and second lenses on the optical axis and the thicknesses of the first and second spacer elements facilitates further miniaturization of the lens head thickness, and more specifically, facilitates miniaturization of the lens head thickness along the optical axis. Controlling the air spacing between the first and second lenses facilitates the rational distribution of the thicknesses of the first and second lenses, achieving an optimal assembly process, and improving assembly stability.

[0066] In an exemplary embodiment, the optical system according to the present application may satisfy the following relationship: 3.2 < (d0s - d1s) / (DT11 - DT12) < 4.0, where d0s is the inner diameter of the object-side end surface of the lens barrel, d1s is the inner diameter of the object-side surface of the first spacer element, DT11 is the diameter of the light-transmitting portion of the object-side surface of the first lens element, and DT12 is the diameter of the light-transmitting portion of the image-side surface of the first lens element. More specifically, d0s, d1s, DT11, and DT12 may further satisfy 2.9 < (d0s - d1s) / (DT11 - DT12) < 4.0. Satisfying 3.2<(d0s-d1s) / (DT11-DT12)<4.0 can ensure the smooth flow of the main optical path of the lens and achieve wide-angle imaging. At the same time, controlling the inner diameter of the object side end face of the lens barrel ensures the required dispensing width of the lens production process, so that the object side end face of the lens barrel and other mechanical components can be connected by dispensing. Suppressing the inner diameter of the object side face of the first spacer is beneficial to preventing the first lens from generating internal reflected stray light and reducing the influence of stray light on imaging.

[0067] In an exemplary embodiment, the optical system according to the present application may satisfy: -2.8 < R5 / R6 < -1.65 and 1.2 < f3 / d3s < 1.6, where R5 is the radius of curvature of the object side surface of the third lens, R6 is the radius of curvature of the image side surface of the third lens, f3 is the effective focal length of the third lens, and d3s is the inner diameter of the object side surface of the third spacer element. By satisfying -2.8 < R5 / R6 < -1.65 and 1.2 < f3 / d3s < 1.6, controlling the radius of curvature of the object side surface and the radius of curvature of the image side surface of the third lens can control the transmission of light passing through the third lens along the desired path. At the same time, by controlling the ratio of the focal length of the third lens to the inner diameter of the object side surface of the third spacer element, the transmission of light is ensured, the sensitivity of the lens is reduced, and the inner diameter of the third spacer element is restricted to effectively block stray light without affecting the chief ray.

[0068] In an exemplary embodiment, the optical system according to the present application may satisfy: 0.8 < f4 / (D3m - d3m) < 2.6, where f4 is the effective focal length of the fourth lens, D3m is the outer diameter of the image side surface of the third spacer element, and d3m is the inner diameter of the image side surface of the third spacer element. By satisfying 0.8 < f4 / (D3m - d3m) < 2.6, the bearing area of the image side surface of the third spacer element can be ensured, guaranteeing the stability of the lens bearing. At the same time, by restricting the effective focal length of the fourth lens, the stability of the chief ray of the lens can be guaranteed.

[0069] In an exemplary embodiment, the optical system according to the present application may satisfy: 1.95 < DT11 / (D0s - d0s) < 2.8, where DT11 is the diameter of the light-transmitting part of the object side surface of the first lens, D0s is the outer diameter of the object-side end face of the lens barrel, and d0s is the inner diameter of the object-side end face of the lens barrel. By satisfying 1.5 < DT11 / (D0s - d0s) < 3.2, restricting the difference between the outer diameter and the inner diameter of the object-side end face of the lens barrel is beneficial to ensuring the molding of the lens barrel, preventing appearance problems of the lens barrel. At the same time, by restricting the above ratio, the dispensing width in the lens production process is further restricted to meet the process requirements, enabling the connection between the object-side end face of the lens barrel and other structural components through dispensing.

[0070] In an exemplary embodiment, the optical system according to the present application may satisfy: 0.8 < CT3 / EP23 < 1.35 and 1.0 ≤ CT3 / CT4 < 1.35, where EP23 is the distance between the second spacer element and the third spacer element along the optical axis direction, CT3 is the central thickness of the third lens on the optical axis, and CT4 is the central thickness of the fourth lens on the optical axis. Satisfying 0.8 < CT3 / EP23 < 1.35 and 1.0 ≤ CT3 / CT4 < 1.35, by restricting the ratio of CT3 to EP23 within a reasonable range, the stability of the molding process of the third lens can be ensured, which is beneficial to improving the surface accuracy of the third lens. At the same time, by restricting the ratio of CT3 to CT4 and reasonably distributing the central thicknesses of the third lens and the fourth lens, the uniformity of the lens and the stability of the overall structure are ensured, and the imaging quality is improved.

[0071] In an exemplary embodiment, the optical system according to the present application may satisfy: 0.9 < f23 / (EP12 + EP23) < 1.2, where f23 is the combined focal length of the second lens and the third lens, EP12 is the distance between the first spacer element and the second spacer element along the optical axis direction, and EP23 is the distance between the second spacer element and the third spacer element along the optical axis direction. Satisfying 0.9 < f23 / (EP12 + EP23) < 1.2 and controlling EP12 and EP23 helps to control the edge thicknesses of the second lens and the third lens, ensure the molding of the second lens and the third lens, and at the same time control the combined focal length of the second lens and the third lens, ensuring the correct transmission of the chief ray.

[0072] In an exemplary embodiment, the optical system according to the present application may satisfy: 1.2 < CT2 / CT3 < 2.3 and 1.1 < CT2 / EP12 < 1.35, where CT2 is the central thickness of the second lens on the optical axis, CT3 is the central thickness of the third lens on the optical axis, and EP12 is the distance between the first spacer element and the second spacer element along the optical axis direction. Satisfying 1.2 < CT2 / CT3 < 2.3 and 1.1 < CT2 / EP12 < 1.35 can control the ratio of the central thicknesses of the second lens and the third lens, ensure the molding of the second lens and the third lens, and at the same time control the edge thickness of the second lens, which helps to reduce the influence of internal stray light of the second lens on the performance of the imaging lens.

[0073] An optical system according to an exemplary embodiment of the present application may include: a lens barrel and a lens group disposed within the lens barrel. Among them, the lens group sequentially includes, from the object side to the image side along the optical axis: a first lens with a negative optical power, a second lens with a positive optical power, a third lens with a positive optical power, and a fourth lens with a positive optical power; the optical system further includes a first spacer element and a second spacer element. Among them, the first spacer element is disposed on the image side of the first lens and at least partially contacts the image side surface of the first lens, and the second spacer element is disposed on the image side of the second lens and at least partially contacts the image side surface of the second lens; the optical system satisfies: 1.2 < CT2 / CT3 < 2.3 and 1.1 < CT2 / EP12 < 1.35, where CT2 is the central thickness of the second lens on the optical axis, CT3 is the central thickness of the third lens on the optical axis, and EP12 is the spacing distance between the first spacer element and the second spacer element along the optical axis direction. Satisfying 1.2 < CT2 / CT3 < 2.3 and 1.1 < CT2 / EP12 < 1.35 can control the ratio of the central thicknesses of the second lens and the third lens, ensure the molding of the second lens and the third lens, and at the same time control the edge thickness of the second lens, which helps to reduce the influence of internal stray light of the second lens on the performance of the imaging lens.

[0074] In an embodiment of the present application, at least one of the mirror surfaces of each lens is an aspherical mirror surface, that is, at least one of the object side surface of the first lens to the image side surface of the fourth lens is an aspherical mirror surface. The characteristics of an aspherical lens are that the curvature changes continuously from the center of the lens to the periphery of the lens. Different from a spherical lens with a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has better curvature radius characteristics and has the advantages of improving distortion aberration and improving astigmatism aberration. After using an aspherical lens, it is possible to eliminate the aberration that appears during imaging as much as possible, thereby improving the imaging quality. Optionally, the object side surfaces and image side surfaces of all the lenses from the first lens to the fourth lens are aspherical mirror surfaces.

[0075] In an exemplary embodiment, the above optical system may further include a filter for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the imaging surface.

[0076] The optical system according to the above-described embodiments of the present application can utilize multiple lenses, such as the four lenses described above. By rationally allocating the optical power and surface shape of each lens, as well as the arrangement of the spacer elements, the span of each gear of the lens and the lens barrel can be made more uniform, thereby enhancing the light convergence capability and improving the imaging quality of the optical system. However, those skilled in the art will appreciate that, without departing from the technical solutions claimed in this application, the number of lenses comprising the optical system can be varied to achieve the various results and advantages described herein. For example, although the embodiments are described using four lenses as an example, the optical system is not limited to including four lenses. If desired, the optical system may also include other numbers of lenses.

[0077] The following further describes a specific embodiment of the optical system applicable to the above-mentioned embodiment with reference to the accompanying drawings. Figures 2A to 3C Describe the optical system according to Examples 1 to 3 of the present application; refer to Figures 4A to 5C Describe the optical system according to Examples 4 to 6 of the present application; refer to Figures 6A to 7C Optical systems according to Examples 7 to 9 of the present application are described.

[0078] Example 1

[0079] Figure 2A FIG. 1 shows a schematic structural diagram of an optical system 1001 according to Example 1 of the present application. Figure 2A As shown, the optical system 1001 includes a lens barrel P0, a lens group, and a spacer element group.

[0080] like Figure 2A As shown, the lens group of optical system 1001 includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4. The first lens E1 has an object-side surface S1 and an image-side surface S2. The second lens E2 has an object-side surface S3 and an image-side surface S4. The third lens E3 has an object-side surface S5 and an image-side surface S6. The fourth lens E4 has an object-side surface S7 and an image-side surface S8. The optical system 1001 also includes an aperture stop STO (not shown) disposed between the second and third lenses, and a filter (not shown) for correcting chromatic aberration, the filter having an object-side surface S9 and an image-side surface S10. Light from an object sequentially passes through each surface S1 to S10 and is ultimately imaged on an imaging surface (not shown).

[0081] Table 2-1 shows the basic parameters of the lens group of the optical system 1001 of Example 1, wherein the units of curvature radius, thickness / distance and effective focal length are all millimeters (mm).

[0082]

[0083]

[0084] Table 2-1

[0085] In Example 1, the object-side surface and the image-side surface of any lens among the first lens E1 to the fourth lens E4 are both aspherical surfaces. The surface shape of each aspherical lens can be defined by, but is not limited to, the following aspherical surface formula:

[0086]

[0087] Wherein, x is the distance vector height of the aspheric surface from the vertex of the aspheric surface at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the curvature radius R in Table 2-1 above); k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. Table 2-2 lists the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A 10 、A 12 、A 14 、A 16 、A 18 and A 20 .

[0088] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 5.6792E-01 -1.0398E-01 2.6156E-02 -8.0135E-03 2.6239E-03 -8.6360E-04 2.6459E-04 -7.7410E-05 2.0496E-05 S2 3.6828E-02 1.0268E-02 -3.4451E-03 -1.1773E-03 -8.3546E-04 -1.4903E-04 5.6321E-06 2.6190E-06 1.2677E-05 S3 -5.8383E-02 7.2106E-03 -1.7502E-03 -3.9547E-04 -2.6234E-04 -5.6671E-05 -3.2808E-06 -8.9079E-06 1.1476E-06 S4 5.4087E-03 7.8312E-04 1.0946E-04 5.1776E-05 8.6948E-06 -1.8142E-06 -7.3535E-06 -1.1307E-06 -1.2906E-07 S5 5.4786E-03 3.3324E-03 3.2403E-04 -5.3994E-05 -1.9964E-05 -3.7206E-06 6.2048E-06 -1.5201E-06 1.1373E-06 S6 -8.5108E-02 2.3745E-02 -4.2157E-05 2.0036E-03 1.5130E-04 1.5305E-04 1.0834E-05 -1.2722E-05 9.9898E-06 S7 -2.9957E-01 2.8814E-02 -7.2394E-03 2.6337E-03 -5.1677E-04 3.3118E-04 -6.3809E-05 -8.3223E-07 0.0000E+00 S8 -2.2443E-01 -1.1976E-02 -1.1643E-04 -1.3157E-03 5.2594E-04 -7.6653E-05 9.3019E-05 5.3729E-08 0.0000E+00

[0089] Table 2-2

[0090] Table 3 shows the values of the maximum field angle FOV, the effective focal length f, and the combined focal length f23 of the optical system 1001.

[0091] parameter FOV(°) f(mm) f23(mm) Numerical 136.0000 0.6000 0.7835

[0092] Table 3

[0093] like Figure 2A As shown, optical system 1001 also includes four spacer elements, namely a first spacer element P1, a second spacer element P2, a third spacer element P3, and a third auxiliary spacer element P3b. First spacer element P1 is positioned on the image side of the first lens and at least partially contacts the image side surface of the first lens; second spacer element P2 is positioned on the image side of the second lens and at least partially contacts the image side surface of the second lens; third spacer element P3 is positioned on the image side of the third lens and at least partially contacts the image side surface of the third lens; and third auxiliary spacer element P3b is positioned on the image side of the third spacer element and at least partially contacts the third spacer element. Table 4 shows the basic parameters of the spacer elements and lens barrel of optical system 1001. The units of each parameter in Table 4 are millimeters (mm). The above-mentioned spacer elements can block excess light from the edge of the lens, allowing the lens and lens barrel to better support each other, and enhancing the structural stability of optical system 1001.

[0094] parameter d1s d1m D1s D1m d2m D2m d3s d3m D3m Numerical 0.9438 0.9838 2.6691 2.6691 0.4441 2.1567 1.1100 1.3659 1.9069 parameter d0s D0s D0m CP1 EP12 CP2 EP23 CP3 L Numerical 2.8049 3.2891 2.6730 0.0220 0.3883 0.0160 0.3026 0.2981 2.2774

[0095] Table 4

[0096] Example 2

[0097] Figure 2B FIG2 is a schematic structural diagram of an optical system 1002 according to Embodiment 2 of the present application. In this embodiment and the following embodiments, for the sake of brevity, some descriptions similar to those in Embodiment 1 will be omitted.

[0098] like Figure 2B As shown, optical system 1002 includes a lens barrel P0, a lens group, and a spacer element group. Optical system 1002 also includes a stop STO (not shown) disposed between the second lens and the third lens. The lens group of optical system 1002 is identical to that of optical system 1001 in Example 1. Their basic parameters are detailed in Tables 2-1 to 3 and are not further described.

[0099] like Figure 2B As shown, optical system 1002 also includes three spacer elements, namely a first spacer element P1, a second spacer element P2, and a third spacer element P3. First spacer element P1 is positioned on the image side of the first lens and at least partially contacts the image side surface of the first lens; second spacer element P2 is positioned on the image side of the second lens and at least partially contacts the image side surface of the second lens; and third spacer element P3 is positioned on the image side of the third lens and at least partially contacts the image side surface of the third lens. Table 5 shows the basic parameters of the spacer elements and lens barrel of optical system 1002. The units of each parameter in Table 5 are millimeters (mm). The above-mentioned spacer elements can block excess light from the edge of the lens, allowing the lens and lens barrel to better support each other and enhance the structural stability of optical system 1002.

[0100] parameter d1s d1m D1s D1m d2m D2m d3s d3m D3m Numerical 0.9201 0.9601 2.6057 2.6057 0.4488 2.3389 1.0016 1.3459 1.8744 parameter d0s D0s D0m CP1 EP12 CP2 EP23 CP3 L Numerical 2.8505 3.2057 2.7330 0.0220 0.3845 0.0220 0.3201 0.3000 2.3074

[0101] Table 5

[0102] Example 3

[0103] Figure 2C A schematic structural diagram of the optical system 1003 according to Example 3 of the present application is shown.

[0104] like Figure 2C As shown, optical system 1003 includes a lens barrel P0, a lens group, and a spacer element group. Optical system 1003 also includes a stop STO (not shown) disposed between the second lens and the third lens. The lens group of optical system 1003 is identical to that of optical system 1001 in Example 1. Their basic parameters are detailed in Tables 2-1 to 3 and are not further described.

[0105] like Figure 2C As shown, optical system 1003 also includes four spacer elements, namely a first spacer element P1, a second spacer element P2, a third spacer element P3, and a third auxiliary spacer element P3b. First spacer element P1 is positioned on the image side of the first lens and at least partially contacts the image side surface of the first lens; second spacer element P2 is positioned on the image side of the second lens and at least partially contacts the image side surface of the second lens; third spacer element P3 is positioned on the image side of the third lens and at least partially contacts the image side surface of the third lens; and third auxiliary spacer element P3b is positioned on the image side of the third spacer element and at least partially contacts the third spacer element. Table 6 shows the basic parameters of the spacer elements and lens barrel of optical system 1003. The units of each parameter in Table 6 are millimeters (mm). The above spacer elements can block excess light from the edge of the lens, allowing the lens and lens barrel to better support each other, and enhancing the structural stability of optical system 1003.

[0106] parameter d1s d1m D1s D1m d2m D2m d3s d3m D3m Numerical 0.9873 1.0113 2.5133 2.5133 0.4411 2.1207 0.9048 0.9328 2.0244 parameter d0s D0s D0m CP1 EP12 CP2 EP23 CP3 L Numerical 2.7415 3.2257 2.6530 0.0140 0.3849 0.0160 0.3485 0.0160 2.2899

[0107] Table 6

[0108] Figure 3A The axial chromatic aberration curves of the optical systems of Examples 1 to 3 are shown, which indicate the deviation of the convergence point of light of different wavelengths after passing through the lens. Figure 3B Astigmatism curves of the optical systems of Examples 1 to 3 are shown, which indicate meridional field curvature and sagittal field curvature. Figure 3C The magnification chromatic aberration curves of the optical systems of Examples 1 to 3 are shown, which represent the deviations of different image heights on the imaging surface after the light passes through the lens. Figures 3A to 3C It can be seen that the optical systems provided in Examples 1 to 3 can achieve good imaging quality.

[0109] Example 4

[0110] Figure 4A FIG. 2 shows a schematic structural diagram of an optical system 2001 according to embodiment 4 of the present application. Figure 4A As shown, the optical system 2001 includes a lens barrel P0, a lens group, and a spacer element group.

[0111] like Figure 4AAs shown, the lens group of optical system 2001 includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4. The first lens E1 has an object-side surface S1 and an image-side surface S2. The second lens E2 has an object-side surface S3 and an image-side surface S4. The third lens E3 has an object-side surface S5 and an image-side surface S6. The fourth lens E4 has an object-side surface S7 and an image-side surface S8. The optical system 2001 also includes an aperture stop STO (not shown) disposed between the second and third lenses, and a filter (not shown) for correcting chromatic aberration, the filter having an object-side surface S9 and an image-side surface S10. Light from an object sequentially passes through each surface S1 to S10 and is ultimately imaged on an imaging surface (not shown).

[0112] Table 7 shows the basic parameters of the lens assembly of optical system 2001 in Example 4, where the units of curvature radius, thickness / distance, and effective focal length are all in millimeters (mm). Table 8 shows the high-order coefficients of each aspheric mirror surface that can be used in Example 4, where the surface shape of each aspheric surface can be defined by formula (1) given in Example 1 above.

[0113]

[0114] Table 7

[0115] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 6.8732E-01 -1.2462E-01 2.9898E-02 -8.4809E-03 2.6089E-03 -7.9869E-04 2.5822E-04 -6.8026E-05 1.1047E-05 S2 7.5107E-02 7.4474E-03 -2.5609E-03 -1.5629E-03 -7.8647E-04 -3.5322E-04 -1.0282E-04 -2.5892E-05 1.9400E-05 S3 -3.2930E-02 9.6877E-04 -1.4588E-03 -4.6687E-04 -1.9445E-04 -8.0307E-05 -1.8368E-05 1.1519E-06 1.6562E-06 S4 5.8539E-03 3.9266E-04 -8.3004E-07 9.1723E-06 -8.3034E-07 5.3359E-06 -3.3697E-06 -1.2892E-06 -7.8391E-07 S5 1.2000E-02 1.9745E-03 4.6733E-04 3.3794E-05 -2.8318E-05 -9.4451E-06 5.4924E-06 -1.1135E-06 2.6565E-07 S6 -5.2350E-02 1.2565E-02 -4.7281E-04 1.5588E-03 8.2188E-06 1.2137E-04 -8.1777E-06 -5.2520E-06 1.3118E-06 S7 -1.2344E-01 3.4353E-03 -3.9170E-03 1.6424E-03 -3.4011E-04 1.1978E-04 -6.9965E-05 -8.1092E-08 0.0000E+00 S8 -4.3451E-02 -1.6941E-02 1.3058E-04 2.2684E-04 -6.3970E-05 -9.4728E-05 9.8435E-06 8.4226E-09 0.0000E+00

[0116] Table 8

[0117] Table 9 shows the values of the maximum field angle FOV, effective focal length f, and combined focal length f23 of the optical system 2001.

[0118] parameter FOV(°) f(mm) f23(mm) Numerical 135.8758 0.6043 1.1050

[0119] Table 9

[0120] like Figure 4A As shown, optical system 2001 also includes three spacer elements: a first spacer element P1, a second spacer element P2, and a third spacer element P3. First spacer element P1 is positioned on the image side of the first lens and at least partially contacts the image-side surface of the first lens; second spacer element P2 is positioned on the image side of the second lens and at least partially contacts the image-side surface of the second lens; and third spacer element P3 is positioned on the image side of the third lens and at least partially contacts the image-side surface of the third lens. Table 10 shows basic parameters of the spacer elements and lens barrel of optical system 2001. The units of each parameter in Table 10 are millimeters (mm). These spacer elements can block excess external light, allowing the lenses and lens barrel to better support each other, and enhancing the structural stability of optical system 2001.

[0121] parameter d1s d1m D1s D1m d2m D2m d3s d3m D3m Numerical 1.1252 1.1652 3.7936 3.7936 0.5560 2.7035 0.9439 0.9839 2.6304 parameter d0s D0s D0m CP1 EP12 CP2 EP23 CP3 L Numerical 3.9294 4.3936 3.2304 0.0220 0.7827 0.0220 0.3963 0.0220 3.0656

[0122] Table 10

[0123] Example 5

[0124] Figure 4B A schematic structural diagram of an optical system 2002 according to embodiment 5 of the present application is shown.

[0125] like Figure 4B As shown, optical system 2002 includes a lens barrel P0, a lens assembly, and a spacer element assembly. Optical system 2002 also includes a stop STO (not shown) disposed between the second lens and the third lens. The lens assembly of optical system 2002 is identical to that of optical system 2001 in Example 4. Their basic parameters are detailed in Tables 7 to 9 and are not further described.

[0126] like Figure 4B As shown, optical system 2002 also includes three spacer elements: a first spacer element P1, a second spacer element P2, and a third spacer element P3. First spacer element P1 is positioned on the image side of the first lens and at least partially contacts the image side surface of the first lens; second spacer element P2 is positioned on the image side of the second lens and at least partially contacts the image side surface of the second lens; and third spacer element P3 is positioned on the image side of the third lens and at least partially contacts the image side surface of the third lens. Table 11 shows the basic parameters of the spacer elements and lens barrel of optical system 2002. The units of each parameter in Table 11 are millimeters (mm). These spacer elements can block excess light from the edges of the lens, allowing the lens and lens barrel to better support each other and enhancing the structural stability of optical system 2002.

[0127] parameter d1s d1m D1s D1m d2m D2m d3s d3m D3m Numerical 1.1140 1.1540 3.6012 3.6012 0.5380 3.1991 0.9662 1.0062 3.1261 parameter d0s D0s D0m CP1 EP12 CP2 EP23 CP3 L Numerical 3.7370 4.2012 3.7261 0.0220 0.7777 0.0160 0.4373 0.0220 3.1199

[0128] Table 11

[0129] Example 6

[0130] Figure 4C A schematic structural diagram of the optical system 2003 according to Example 6 of the present application is shown.

[0131] like Figure 4C As shown, optical system 2003 includes a lens barrel P0, a lens assembly, and a spacer element assembly. Optical system 2003 also includes a stop STO (not shown) disposed between the second lens and the third lens. The lens assembly of optical system 2003 is identical to that of optical system 2001 in Example 4. Their basic parameters are detailed in Tables 7 to 9 and are not further described.

[0132] like Figure 4CAs shown, optical system 2003 also includes three spacer elements, namely a first spacer element P1, a second spacer element P2, and a third spacer element P3. First spacer element P1 is positioned on the image side of the first lens and at least partially contacts the image side surface of the first lens; second spacer element P2 is positioned on the image side of the second lens and at least partially contacts the image side surface of the second lens; and third spacer element P3 is positioned on the image side of the third lens and at least partially contacts the image side surface of the third lens. Table 12 shows basic parameters of the spacer elements and lens barrel of optical system 2003. The units of each parameter in Table 12 are millimeters (mm). These spacer elements can block excess light from the edges of the lens, allowing the lens and lens barrel to better support each other and enhancing the structural stability of optical system 2003.

[0133] parameter d1s d1m D1s D1m d2m D2m d3s d3m D3m Numerical 1.1431 1.1831 3.8554 3.8554 0.5322 2.7945 0.9553 0.9833 2.5109 parameter d0s D0s D0m CP1 EP12 CP2 EP23 CP3 L Numerical 3.9912 4.4554 3.3754 0.0220 0.7743 0.0160 0.4473 0.0160 3.1625

[0134] Table 12

[0135] Figure 5A The axial chromatic aberration curves of the optical systems of Examples 4 to 6 are shown, which indicate the deviation of the convergence point of light of different wavelengths after passing through the lens. Figure 5B Astigmatism curves of the optical systems of Examples 4 to 6 are shown, which indicate meridional field curvature and sagittal field curvature. Figure 5C The magnification chromatic aberration curves of the optical systems of Examples 4 to 6 are shown, which represent the deviations of different image heights on the imaging surface after the light passes through the lens. Figures 5A to 5C It can be seen that the optical systems provided in Examples 4 to 6 can achieve good imaging quality.

[0136] Example 7

[0137] Figure 6A FIG. 3 shows a schematic structural diagram of an optical system 3001 according to Example 7 of the present application. Figure 6A As shown, the optical system 3001 includes a lens barrel P0, a lens group, and a spacer element group.

[0138] like Figure 6AAs shown, the lens group of optical system 3001 includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4. The first lens E1 has an object-side surface S1 and an image-side surface S2. The second lens E2 has an object-side surface S3 and an image-side surface S4. The third lens E3 has an object-side surface S5 and an image-side surface S6. The fourth lens E4 has an object-side surface S7 and an image-side surface S8. The optical system 3001 also includes an aperture stop STO (not shown) disposed between the second and third lenses, and a filter (not shown) for correcting chromatic aberration, the filter having an object-side surface S9 and an image-side surface S10. Light from an object sequentially passes through each surface S1 to S10 and is ultimately imaged on an imaging surface (not shown).

[0139] Table 13 shows the basic parameters of the lens assembly of the optical system 3001 of Example 7, where the units of curvature radius, thickness / distance, and effective focal length are all in millimeters (mm). Table 14 shows the high-order coefficients of the various aspheric mirror surfaces that can be used in Example 7, where the surface shape of each aspheric surface can be defined by formula (1) given in Example 1 above.

[0140]

[0141] Table 13

[0142]

[0143]

[0144] Table 14

[0145] Table 15 shows the numerical values of the maximum field angle FOV, effective focal length f, and combined focal length f23 of the optical system 3001.

[0146] parameter FOV(°) f(mm) f23(mm) Numerical 129.5708 0.6103 0.9911

[0147] Table 15

[0148] like Figure 6AAs shown, optical system 3001 also includes four spacer elements: a first spacer element P1, a second spacer element P2, a third spacer element P3, and a third auxiliary spacer element P3b. First spacer element P1 is positioned on the image side of the first lens and at least partially contacts the image-side surface of the first lens; second spacer element P2 is positioned on the image side of the second lens and at least partially contacts the image-side surface of the second lens; third spacer element P3 is positioned on the image side of the third lens and at least partially contacts the image-side surface of the third lens; and third auxiliary spacer element P3b is positioned on the image side of the third spacer element and at least partially contacts the image-side surface of the third lens. Table 16 shows the basic parameters of the spacer elements and lens barrel of optical system 3001. All parameters in Table 16 are in millimeters (mm). These spacer elements can block excess external light, allowing the lenses and lens barrel to better support each other, and enhancing the structural stability of optical system 3001.

[0149] parameter d1s d1m D1s D1m d2m D2m d3s d3m D3m Numerical 1.0756 1.1156 3.0841 3.0841 0.5165 2.3275 0.9856 1.1683 1.9606 parameter d0s D0s D0m CP1 EP12 CP2 EP23 CP3 L Numerical 3.2200 3.7041 2.8237 0.0220 0.5070 0.0220 0.3197 0.2513 2.7485

[0150] Table 16

[0151] Example 8

[0152] Figure 6B A schematic structural diagram of the optical system 3002 according to Example 8 of the present application is shown.

[0153] like Figure 6B As shown, optical system 3002 includes a lens barrel P0, a lens group, and a spacer element group. Optical system 3002 also includes a stop STO (not shown) disposed between the second lens and the third lens. The lens group of optical system 3002 is identical to that of optical system 3001 in Example 7. Their basic parameters are detailed in Tables 13 to 15 and are not further described.

[0154] like Figure 6B As shown, optical system 3002 also includes four spacer elements: a first spacer element P1, a second spacer element P2, a third spacer element P3, and a third auxiliary spacer element P3b. First spacer element P1 is positioned on the image side of the first lens and at least partially contacts the image-side surface of the first lens; second spacer element P2 is positioned on the image side of the second lens and at least partially contacts the image-side surface of the second lens; third spacer element P3 is positioned on the image side of the third lens and at least partially contacts the image-side surface of the third lens; and third auxiliary spacer element P3b is positioned on the image side of the third spacer element and at least partially contacts the image-side surface of the third lens. Table 17 shows the basic parameters of the spacer elements and lens barrel of optical system 3002. All parameters in Table 17 are in millimeters (mm). These spacer elements can block excess light from the edges of the lens, allowing the lens and lens barrel to better support each other and enhancing the structural stability of optical system 3002.

[0155] parameter d1s d1m D1s D1m d2m D2m d3s d3m D3m Numerical 1.0551 1.0831 3.1738 3.1738 0.4964 2.7441 1.0257 1.2514 2.3856 parameter d0s D0s D0m CP1 EP12 CP2 EP23 CP3 L Numerical 3.3152 3.7938 3.1964 0.0160 0.5115 0.0160 0.3257 0.2573 2.8013

[0156] Table 17

[0157] Example 9

[0158] Figure 6C A schematic structural diagram of the optical system 3003 according to Example 9 of the present application is shown.

[0159] like Figure 6C As shown, optical system 3003 includes a lens barrel P0, a lens group, and a spacer element group. Optical system 3003 also includes a stop STO (not shown) disposed between the second lens and the third lens. The lens group of optical system 3003 is identical to that of optical system 3001 in Example 7. Their basic parameters are detailed in Tables 13 to 15 and are not further described.

[0160] like Figure 6C As shown, optical system 3003 also includes four spacer elements: a first spacer element P1, a second spacer element P2, a third spacer element P3, and a third auxiliary spacer element P3b. First spacer element P1 is positioned on the image side of the first lens and at least partially contacts the image-side surface of the first lens; second spacer element P2 is positioned on the image side of the second lens and at least partially contacts the image-side surface of the second lens; third spacer element P3 is positioned on the image side of the third lens and at least partially contacts the image-side surface of the third lens; and third auxiliary spacer element P3b is positioned on the image side of the third spacer element and at least partially contacts the image-side surface of the third lens. Table 18 shows the basic parameters of the spacer elements and lens barrel of optical system 3003. The units of each parameter in Table 18 are millimeters (mm). These spacer elements can block excess light from the edges of the lens, allowing the lens and lens barrel to better support each other and enhancing the structural stability of optical system 3003.

[0161] parameter d1s d1m D1s D1m d2m D2m d3s d3m D3m Numerical 1.0423 1.0823 3.3190 3.3190 0.5027 2.4771 0.9128 0.9528 2.2237 parameter d0s D0s D0m CP1 EP12 CP2 EP23 CP3 L Numerical 3.4549 3.9390 2.8237 0.0220 0.5226 0.0220 0.3317 0.0220 2.7985

[0162] Table 18

[0163] Figure 7A The axial chromatic aberration curves of the optical systems of Examples 7 to 9 are shown, which indicate the deviation of the convergence point of light of different wavelengths after passing through the lens. Figure 7B Astigmatism curves of the optical systems of Examples 7 to 9 are shown, which indicate meridional field curvature and sagittal field curvature. Figure 7C The magnification chromatic aberration curves of the optical systems of Examples 7 to 9 are shown, which represent the deviations of different image heights on the imaging surface after the light passes through the lens. 7A to 7C It can be seen that the optical systems provided in Examples 7 to 9 can achieve good imaging quality.

[0164] In summary, the optical systems of Examples 1 to 9 satisfy the relationship shown in Table 19.

[0165] Conditional formula / Example 1 2 3 4 5 6 7 8 9 f / (D0m-D0s) 0.9739 1.2695 1.0478 0.5195 1.2718 0.5596 0.6932 1.0215 0.5472 CT2 / CT3 1.2602 1.2602 1.2602 2.2518 2.2518 2.2518 1.5178 1.5178 1.5178 CT2 / EP12 1.2983 1.3111 1.3098 1.1041 1.1111 1.1160 1.1978 1.1875 1.1622 DT11 / (D0s-d0s) 1.9887 2.7111 1.9887 2.7939 2.7939 2.7939 2.5070 2.5360 2.5070 Tan(FOV / 2)×L 5.6368 5.7110 5.6677 7.5641 7.6979 7.8032 5.8370 5.9492 5.9432 (D1s-d1m) / (f1+f2) 5.6328 5.4999 5.0198 3.3702 3.1379 3.4264 3.4271 3.6398 3.8940 CP3 / T34 3.3826 3.4041 0.1816 0.7333 0.7333 0.5333 8.3781 8.5781 0.7333 R2 / R3 1.0870 1.0870 1.0870 0.7902 0.7902 0.7902 0.9452 0.9452 0.9452 f12 / EP12 -5.9665 -6.0251 -6.0194 -2.2722 -2.2867 -2.2968 -3.2925 -3.2640 -3.1947 (D1m-d1m) / (D2m-d2m) 0.9841 0.8706 0.8942 1.2239 0.9196 1.1813 1.0870 0.9301 1.1328 T12 / (CP1+CP2) 2.8813 2.4884 3.6496 6.0799 7.0399 7.0399 4.0887 5.6220 4.0887 <h2 style=";text-align:left;direction:ltr">(d0s-d1s) / (DT11-DT12) 3.8255 3.9678 3.6056 3.8615 3.6120 3.9218 3.2209 3.3947 3.6237 <h2 style=";text-align:left;direction:ltr"> R5 / R6 -1.6861 -1.6861 -1.6861 -1.7373 -1.7373 -1.7373 -2.7789 -2.7789 -2.7789 <h2 style=";text-align:left;direction:ltr"> f3 / d3s 1.2917 1.4315 1.5846 1.5611 1.5250 1.5424 1.2662 1.2167 1.3673 <h2 style=";text-align:left;direction:ltr"> f4 / (D3m-d3m) 2.4788 2.5371 1.2285 1.1047 0.8581 1.1908 2.4007 1.6772 1.4967 <h2 style=";text-align:left;direction:ltr"> CT3 / EP23 1.3217 1.2497 1.1477 0.9684 0.8776 0.8579 1.2516 1.2285 1.2062 <h2 style=";text-align:left;direction:ltr"> f23 / (EP12+EP23) 1.1339 1.1119 1.0682 0.9373 0.9095 0.9045 1.1987 1.1838 1.1601 <h2 style=";text-align:left;direction:ltr"> CT3 / CT4 1.3084 1.3084 1.3084 1.0000 1.0000 1.0000 1.3364 1.3364 1.3364

[0166] Table 19

[0167] The present application also provides an imaging device, wherein the electronic photosensitive element thereof may be a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The imaging device may be a standalone imaging device such as a digital camera, or an imaging module integrated into a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical system described above.

[0168] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the invention herein is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the inventive concept. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features having similar functions disclosed in this application.

Claims

1. An optical system, characterized in that: Comprising: A lens barrel and a lens group disposed within the lens barrel, wherein, The lens group sequentially includes, from the object side to the image side along the optical axis: A first lens having a negative optical power; A second lens having a positive optical power; A third lens having a positive optical power; and A fourth lens having a positive optical power; The number of lenses with optical power in the optical system is four; The maximum field angle FOV of the optical system and the maximum length L of the lens barrel along the optical axis direction satisfy: 5.6 < Tan(FOV / 2) × L < 7.85; The effective focal length f of the optical system, the outer diameter D0m of the image-side end face of the lens barrel, and the outer diameter D0s of the object-side end face of the lens barrel satisfy: 0.5 < f / (D0m - D0s) < 1.

3.

2. The optical system according to claim 1, wherein: The optical system further includes a first spacer element disposed on the image side of the first lens and at least partially contacting the image side face of the first lens; The optical system satisfies: 3.1 < (D1s - d1m) / (f1 + f2) < 5.65, where D1s is the outer diameter of the object side face of the first spacer element, d1m is the inner diameter of the image side face of the first spacer element, f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens.

3. The optical system according to claim 1, wherein, The optical system further includes a third spacer element disposed on the image side of the third lens and at least partially contacting the image side face of the third lens; There is an air gap on the optical axis between any two adjacent lenses from the first lens to the fourth lens, and the air gap on the optical axis between the third lens and the fourth lens is the smallest; The optical system satisfies: 0.13 < CP3 / T34 < 8.6, where CP3 is the maximum thickness of the third spacer element along the optical axis direction, R3 is the curvature radius of the object side face of the second lens, and T34 is the air gap on the optical axis between the third lens and the fourth lens.

4. The optical system according to claim 1, wherein, The optical system further includes a first spacer element and a second spacer element, wherein the first spacer element is disposed on the image side of the first lens and at least partially contacts the image side face of the first lens, and the second spacer element is disposed on the image side of the second lens and at least partially contacts the image side face of the second lens; The optical system satisfies: 0.75 < R2 / R3 < 1.1 and -6.1 < f12 / EP12 < -2.2, where R2 is the curvature radius of the image side face of the first lens, R3 is the curvature radius of the object side face of the second lens, f12 is the combined focal length of the first lens and the second lens, and EP12 is the spacer distance between the first spacer element and the second spacer element along the optical axis direction.

5. The optical system according to claim 1, wherein, The optical system further includes a first spacer element and a second spacer element. Wherein, the first spacer element is disposed on the image side of the first lens and at least partially contacts the image-side surface of the first lens, and the second spacer element is disposed on the image side of the second lens and at least partially contacts the image-side surface of the second lens; The optical system satisfies: 0.82 < (D1m - d1m) / (D2m - d2m) < 1.26, where D1m is the outer diameter of the image-side surface of the first spacer element, d1m is the inner diameter of the image-side surface of the first spacer element, D2m is the outer diameter of the image-side surface of the second spacer element, and d2m is the inner diameter of the image-side surface of the second spacer element.

6. The optical system according to claim 1, wherein The optical system further includes a first spacer element and a second spacer element. Wherein, the first spacer element is disposed on the image side of the first lens and at least partially contacts the image-side surface of the first lens, and the second spacer element is disposed on the image side of the second lens and at least partially contacts the image-side surface of the second lens; The optical system satisfies: 2.4 < T12 / (CP1 + CP2) < 7.1, where T12 is the air gap between the first lens and the second lens on the optical axis, CP1 is the maximum thickness of the first spacer element along the optical axis direction, and CP2 is the maximum thickness of the second spacer element along the optical axis direction.

7. The optical system according to claim 1, wherein The optical system further includes a first spacer element disposed on the image side of the first lens and at least partially contacting the image-side surface of the first lens; The optical system satisfies: 3.2 < (d0s - d1s) / (DT11 - DT12) < 4.0, where d0s is the inner diameter of the object-side end face of the lens barrel, d1s is the inner diameter of the object-side surface of the first spacer element, DT11 is the diameter of the light-transmitting portion of the object-side surface of the first lens, and DT12 is the diameter of the light-transmitting portion of the image-side surface of the first lens.

8. The optical system according to any one of claims 1, 2, 4 - 7, wherein The optical system further includes a third spacer element disposed on the image side of the third lens and at least partially contacting the image-side surface of the third lens; The optical system satisfies: -2.8 < R5 / R6 < -1.65 and 1.2 < f3 / d3s < 1.6, where R5 is the curvature radius of the object-side surface of the third lens, R6 is the curvature radius of the image-side surface of the third lens, f3 is the effective focal length of the third lens, and d3s is the inner diameter of the object-side surface of the third spacer element.

9. The optical system according to any one of claims 1, 2, 4 - 7, wherein The optical system further includes a third spacer element disposed on the image side of the third lens and at least partially contacting the image-side surface of the third lens; The optical system satisfies: 0.8 < f4 / (D3m - d3m) < 2.6, where f4 is the effective focal length of the fourth lens, D3m is the outer diameter of the image side surface of the third spacer element, and d3m is the inner diameter of the image side surface of the third spacer element.

10. The optical system according to any one of claims 1-7, wherein the optical system satisfies: 1.95 < DT11 / (D0s - d0s) < 2.8, where DT11 is the diameter of the light-transmitting portion of the object side surface of the first lens, D0s is the outer diameter of the object side end surface of the lens barrel, and d0s is the inner diameter of the object side end surface of the lens barrel.

11. The optical system according to any one of claims 1, 2, 4-7, wherein the optical system further includes a second spacer element and a third spacer element, wherein the second spacer element is disposed on the image side of the second lens and at least partially contacts the image side surface of the second lens, and the third spacer element is disposed on the image side of the third lens and at least partially contacts the image side surface of the third lens; the optical system satisfies: 0.8 < CT3 / EP23 < 1.35 and 1.0 ≤ CT3 / CT4 < 1.35, where EP23 is the spacing distance between the second spacer element and the third spacer element along the optical axis direction, CT3 is the central thickness of the third lens on the optical axis, and CT4 is the central thickness of the fourth lens on the optical axis.

12. The optical system according to any one of claims 1, 2, 4-7, wherein the optical system further includes a first spacer element, a second spacer element and a third spacer element, wherein the first spacer element is disposed on the image side of the first lens and at least partially contacts the image side surface of the first lens, the second spacer element is disposed on the image side of the second lens and at least partially contacts the image side surface of the second lens, and the third spacer element is disposed on the image side of the third lens and at least partially contacts the image side surface of the third lens; the optical system satisfies: 0.9 < f23 / (EP12 + EP23) < 1.2, where f23 is the combined focal length of the second lens and the third lens, EP12 is the spacing distance between the first spacer element and the second spacer element along the optical axis direction, and EP23 is the spacing distance between the second spacer element and the third spacer element along the optical axis direction.

13. The optical system according to any one of claims 1-7, wherein the optical system further includes a first spacer element and a second spacer element, wherein the first spacer element is disposed on the image side of the first lens and at least partially contacts the image side surface of the first lens, and the second spacer element is disposed on the image side of the second lens and at least partially contacts the image side surface of the second lens; among the first lens to the fourth lens, the second lens has the largest central thickness on the optical axis. The optical system satisfies: 1.2 < CT2 / CT3 < 2.3 and 1.1 < CT2 / EP12 < 1.35, where CT2 is the central thickness of the second lens on the optical axis, CT3 is the central thickness of the third lens on the optical axis, and EP12 is the distance between the first spacer element and the second spacer element along the optical axis direction.

14. The optical system according to claim 1, wherein the object side surface of the first lens is concave, and the image side surface is concave; the object side surface of the second lens is convex, and the image side surface is concave; the object side surface of the third lens is convex, and the image side surface is convex; the object side surface of the fourth lens is convex, and the image side surface is concave.

Images