Optical system

Abstract

The utility model discloses an optical system. The zoom lens comprises a first lens with positive focal power, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with positive focal power, a fifth lens with negative focal power, a sixth lens with positive focal power and a seventh lens with positive focal power in sequence from an object side to an image side along an optical axis, the eighth lens has negative focal power; the ninth lens has negative focal power; the object side surface of the sixth lens is a convex surface, and the image side surface is a concave surface; the number of the lenses with the focal power of the optical system is nine.

Description

Technical Field

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

[0002] In recent years, with the continuous advancement of science and technology, spotting lenses have been widely used in field hunting, sports shooting, distance measurement, etc., and higher requirements have been placed on the imaging quality of spotting lenses.

[0003] However, existing sighting lenses often have some issues. For example, they are heavy and bulky, making them difficult to port. Alternatively, they struggle to achieve long focal lengths and high image quality while maintaining miniaturization, making them incapable of discerning minute details. Furthermore, their image quality is poor at night, making them incapable of nighttime observation. Utility Model Content

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

[0005] In one aspect, the present application provides an optical system comprising, in order from the object side to the image side along the optical axis, a first lens having positive optical power, a second lens having positive optical power, a third lens having negative optical power, a fourth lens having positive optical power, a fifth lens having negative optical power, a sixth lens having positive optical power, a seventh lens having positive optical power, an eighth lens having negative optical power, and a ninth lens having negative optical power. The object-side surface of the sixth lens is convex, and the image-side surface is concave. The optical system comprises nine lenses having optical powers.

[0006] According to an exemplary embodiment of the present application, the object-side surface of the first lens is convex, 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 concave; the object-side surface of the fourth lens is convex, and the image-side surface is convex or concave; the object-side surface of the fifth lens is convex or concave, and the image-side surface is concave; the object-side surface of the seventh lens is convex, and the image-side surface is convex; the object-side surface of the eighth lens is concave, and the image-side surface is concave; and the object-side surface of the ninth lens is concave, and the image-side surface is convex.

[0007] According to an exemplary embodiment of the present application, the total effective focal length F of the optical system and the total optical length TTL of the optical system satisfy: 0.8≤TTL / F≤1.0.

[0008] According to an exemplary embodiment of the present application, the maximum clear aperture Dmax of the optical system and the total optical length TTL of the optical system satisfy: 0.2≤Dmax / TTL≤0.4.

[0009] According to an exemplary embodiment of the present application, the back focal length BFL of the optical system and the total effective focal length F of the optical system satisfy: 0.1≤BFL / F≤0.3.

[0010] According to one exemplary embodiment of the present application, the second, third, fourth, and fifth lenses are cemented together to form a cemented lens. The second, third, fourth, and fifth lenses are cemented together to form a cemented lens. The combined focal length F2345 of the second, third, fourth, and fifth lenses and the total effective focal length F of the optical system satisfy the following: -0.7 ≤ F2345 / F ≤ -0.5.

[0011] According to an exemplary embodiment of the present application, the effective focal length F1 of the first lens and the total effective focal length F of the optical system satisfy: 0.7≤F1 / F≤1.0.

[0012] According to an exemplary embodiment of the present application, the effective focal length F2 of the second lens and the total effective focal length F of the optical system satisfy: 0.7≤F2 / F≤1.0.

[0013] According to an exemplary embodiment of the present application, the effective focal length F3 of the third lens and the total effective focal length F of the optical system satisfy: -0.5≤F3 / F≤-0.2.

[0014] According to an exemplary embodiment of the present application, the effective focal length F4 of the fourth lens and the total effective focal length F of the optical system satisfy: 0.3≤F4 / F≤0.5.

[0015] According to an exemplary embodiment of the present application, the effective focal length F5 of the fifth lens and the total effective focal length F of the optical system satisfy: -0.4≤F5 / F≤-0.2.

[0016] According to an exemplary embodiment of the present application, the effective focal length F6 of the sixth lens and the total effective focal length F of the optical system satisfy: 0.6≤F6 / F≤0.9.

[0017] According to an exemplary embodiment of the present application, the effective focal length F7 of the seventh lens and the total effective focal length F of the optical system satisfy: 0.1≤F7 / F≤0.3.

[0018] According to an exemplary embodiment of the present application, the effective focal length F8 of the eighth lens and the total effective focal length F of the optical system satisfy: -0.3≤F8 / F≤-0.1.

[0019] According to an exemplary embodiment of the present application, the effective focal length F9 of the ninth lens and the total effective focal length F of the optical system satisfy: -1.0≤F9 / F≤-0.5.

[0020] According to an exemplary embodiment of the present application, the seventh lens and the eighth lens are cemented to form a cemented lens. The combined focal length F78 of the seventh lens and the eighth lens and the total effective focal length F of the optical system satisfy: 0.6≤F78 / F≤1.1.

[0021] According to an exemplary embodiment of the present application, the combined focal length FG1 of the first to sixth lenses and the total effective focal length F of the optical system satisfy: 0.9≤FG1 / F≤1.1.

[0022] According to an exemplary embodiment of the present application, the seventh lens and the eighth lens are cemented to form a cemented lens. The combined focal length FG2 of the seventh to ninth lenses and the total effective focal length F of the optical system satisfy: -8.0≤FG2 / F≤-2.5.

[0023] According to an exemplary embodiment of the present application, the optical system satisfies at least one of the following conditional equations: 65≤VD2≤75, 65≤VD4≤75, 90≤VD6≤100, wherein VD2 is the Abbe number of the second lens, VD4 is the Abbe number of the fourth lens, and VD6 is the Abbe number of the sixth lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Other features, objects and advantages of the present application will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings, in which:

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

[0026] Figure 2 1 shows a schematic structural diagram of an optical system according to Example 2 of the present application;

[0027] Figure 3 1 shows a schematic structural diagram of an optical system according to Example 3 of the present application;

[0028] Figure 4 shows a schematic structural diagram of an optical system according to embodiment 4 of the present application; and

[0029] Figure 5 A structural schematic diagram of an optical system according to Example 5 of the present application is shown. DETAILED DESCRIPTION

[0030] In order to better understand the present application, various aspects of the present application are described in detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application and are not intended to limit the scope of the present application in any way.

[0031] 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.

[0032] 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.

[0033] It should also be understood that the terms "include," "comprising," "having," "including," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. It should be noted that in this specification, the terms "first," "second," "third," and so on, are used only to distinguish one feature from another, and do not represent any limitation on the features.

[0034] Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Terms 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.

[0035] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0036] The optical system according to an exemplary embodiment of the present application may include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens, and the nine lenses are arranged in sequence from the object side to the image side along the optical axis.

[0037] In an exemplary embodiment, the first lens may have positive optical power. The first lens collects light. By setting the first lens as a positive lens, the light emitted from the first lens can be directed as close as possible to the direction of the optical axis, effectively reducing the aperture of the rear lens, thereby miniaturizing the optical system.

[0038] As an example, the object-side surface of the first lens may be convex, and the image-side surface may be concave. By setting the image-side surface of the first lens to be concave, the angle of incidence of on-axis light on the image-side surface of the first lens can be effectively reduced, thereby reducing the spherical aberration generated by the image-side surface of the first lens, thereby achieving high image quality for the optical system.

[0039] In an exemplary embodiment, the second lens may have positive optical power. The object-side surface of the second lens may be convex, and the image-side surface may be concave. By configuring the second lens as a positive lens and the image-side surface of the second lens as a concave surface, the angle of incidence of on-axis light on the image-side surface of the second lens can be effectively reduced, thereby reducing spherical aberration generated by the image-side surface of the second lens, thereby facilitating high image quality in the optical system.

[0040] In an exemplary embodiment, the third lens element may have negative optical power. The object-side surface of the third lens element may be convex, and the image-side surface may be concave. By configuring the third lens element as a negative lens element and having a convex object-side surface, the angle of incidence of on-axis light on the object-side surface of the third lens can be effectively reduced, thereby reducing the spherical aberration generated by the object-side surface of the third lens element, thereby facilitating high image quality in the optical system.

[0041] In an exemplary embodiment, the fourth lens element may have positive optical power. The object-side surface of the fourth lens element may be convex, and the image-side surface may be convex or concave. By configuring the fourth lens element as a positive lens and the object-side surface of the fourth lens element as a convex surface, aberrations can be effectively reduced, thereby achieving high image quality in the optical system.

[0042] In an exemplary embodiment, the fifth lens element may have negative optical power. The object-side surface of the fifth lens element may be convex or concave, and the image-side surface may be concave. By configuring the fifth lens element as a negative lens element and having a concave image-side surface, aberrations can be effectively reduced, thereby achieving high image quality in the optical system.

[0043] In an exemplary embodiment, the sixth lens element may have positive refractive power. The object-side surface of the sixth lens element may be convex, and the image-side surface may be concave. By configuring the sixth lens element in the aforementioned configuration and using a low-dispersion material, the optical system can be apochromatized, achieving infrared confocality.

[0044] In an exemplary embodiment, the seventh lens element may have positive optical power. The object-side surface and image-side surface of the seventh lens element may be convex. By configuring the seventh lens element as a biconvex positive lens, the object-side and image-side surfaces of the seventh lens element can share the optical power of the seventh lens element, reducing the surface curvature of the object-side and image-side surfaces of the seventh lens element, thereby minimizing aberrations and facilitating high image quality for the optical system.

[0045] As an example, the seventh lens and the eighth lens are cemented together to form a cemented lens, such as a doublet. By cementing the seventh lens and the eighth lens together to form a cemented lens, it is beneficial to correct the residual chromatic aberration of the optical system and achieve high image quality of the optical system.

[0046] As an example, the seventh lens has positive power in the cemented lens and is matched with low-dispersion materials, which is conducive to apochromatizing the optical system and achieving infrared confocality of the optical system.

[0047] In an exemplary embodiment, the eighth lens element may have negative optical power. The object-side surface and image-side surface of the eighth lens element may be concave. By configuring the eighth lens element as a biconcave negative lens, the object-side and image-side surfaces of the eighth lens element can share the optical power of the eighth lens element, reducing the surface curvature of the object-side and image-side surfaces of the eighth lens element, thereby minimizing aberrations and facilitating high image quality for the optical system. Furthermore, the eighth lens element, having negative optical power in a cemented lens, can be used in conjunction with the seventh lens element to apochromatize the optical system, achieving high image quality.

[0048] In an exemplary embodiment, the ninth lens element may have negative optical power. The object-side surface of the ninth lens element may be concave, and the image-side surface may be convex. By configuring the ninth lens element as a negative lens element and having a concave object-side surface, the overall optical length of the optical system can be reduced, thereby achieving miniaturization of the optical system.

[0049] As an example, the ninth lens uses a high refractive index material, which can enhance the ninth lens's ability to deflect light, reduce the surface curvature of the object side and image side of the ninth lens, reduce the generation of aberrations, and facilitate achieving high image quality of the optical system.

[0050] In an exemplary embodiment, the second lens, the third lens, the fourth lens, and the fifth lens are cemented to form a cemented lens, for example, a quadruple cemented lens.

[0051] In an exemplary embodiment, the optical system may further include a stop. The stop may be disposed between the first lens and the second lens.

[0052] In an exemplary embodiment, the total effective focal length F of the optical system and the total optical length TTL of the optical system may satisfy the following relationship: 0.8 ≤ TTL / F ≤ 1.0. By properly configuring the ratio of the total optical length of the optical system to the total effective focal length of the optical system, the total optical length of the optical system can be effectively reduced while maintaining a constant total effective focal length, thereby miniaturizing the optical system.

[0053] In an exemplary embodiment, the maximum clear aperture Dmax of the optical system and the total optical length TTL of the optical system can satisfy the following relationship: 0.2≤Dmax / TTL≤0.4. Properly configuring the ratio of the maximum clear aperture to the total optical length of the optical system can reduce the maximum clear aperture of the optical system while maintaining a constant total optical length, thereby facilitating miniaturization of the optical system.

[0054] In an exemplary embodiment, the back focal length BFL of the optical system and the total effective focal length F of the optical system can satisfy the following relationship: 0.1 ≤ BFL / F ≤ 0.3. Properly configuring the ratio of the back focal length to the total effective focal length of the optical system can constrain the back focal length of the optical system within a certain range while achieving miniaturization of the optical system, facilitating assembly of the optical system.

[0055] In an exemplary embodiment, the combined focal length F2345 of the second, third, fourth, and fifth lenses and the total effective focal length F of the optical system can satisfy the following relationship: -0.7 ≤ F2345 / F ≤ -0.5. Properly configuring the ratio of the combined focal length of the second, third, fourth, and fifth lenses to the total effective focal length of the optical system enables the four-lens cemented quadruple to compensate for the on-axis chromatic aberration produced by the first lens, facilitating infrared confocality of the optical system. Furthermore, the four-lens cemented quadruple can have negative focal power, and the positive spherical aberration produced by the four-lens cemented quadruple can effectively compensate for the negative spherical aberration produced by the first lens, thereby achieving high image quality for the optical system.

[0056] In an exemplary embodiment, the effective focal length F1 of the first lens and the total effective focal length F of the optical system can satisfy the following relationship: 0.7 ≤ F1 / F ≤ 1.0. Properly configuring the ratio of the effective focal length of the first lens to the total effective focal length of the optical system can direct light emitted from the first lens toward the optical axis, facilitating a reduction in the aperture of the subsequent lens and, consequently, miniaturizing the optical system.

[0057] In an exemplary embodiment, the effective focal length F2 of the second lens and the total effective focal length F of the optical system can satisfy the following equation: 0.7 ≤ F2 / F ≤ 1.0. Using a low-dispersion material for the second lens and maintaining a reasonable ratio of the effective focal length of the second lens to the total effective focal length of the optical system can effectively reduce chromatic aberration, simplifying chromatic aberration correction within the optical system and achieving high image quality.

[0058] In an exemplary embodiment, the effective focal length F3 of the third lens and the total effective focal length F of the optical system can satisfy the following relationship: -0.5 ≤ F3 / F ≤ -0.2. Properly configuring the ratio of the effective focal length of the third lens to the total effective focal length of the optical system enables the third lens to have negative power in the four-lens cemented lens. This, in combination with the fourth lens, can achieve apochromatism, resulting in high image quality for the optical system.

[0059] In an exemplary embodiment, the effective focal length F4 of the fourth lens and the total effective focal length F of the optical system can satisfy the following equation: 0.3 ≤ F4 / F ≤ 0.5. By using a low-dispersion material for the fourth lens and ensuring a suitable ratio of the fourth lens' effective focal length to the total effective focal length of the optical system, the fourth lens in the four-piece cemented lens can have positive focal power, facilitating apochromatization of the optical system and achieving infrared confocality.

[0060] In an exemplary embodiment, the effective focal length F5 of the fifth lens element and the total effective focal length F of the optical system can satisfy the following relationship: -0.4 ≤ F5 / F ≤ -0.2. Properly configuring the ratio of the effective focal length of the fifth lens element to the total effective focal length of the optical system enables the fifth lens element to have negative focal power in the four-lens cemented lens. This, in combination with the fourth lens element, can achieve apochromatism, thereby achieving high image quality for the optical system.

[0061] In an exemplary embodiment, the effective focal length F6 of the sixth lens and the total effective focal length F of the optical system can satisfy the following relationship: 0.6 ≤ F6 / F ≤ 0.9. Properly configuring the ratio of the effective focal length of the sixth lens to the total effective focal length of the optical system effectively corrects aberrations introduced by the front lens, achieving high image quality for the optical system.

[0062] In an exemplary embodiment, the effective focal length F7 of the seventh lens and the total effective focal length F of the optical system can satisfy the following relationship: 0.1 ≤ F7 / F ≤ 0.3. By using a low-dispersion material for the seventh lens and ensuring a suitable ratio of the effective focal length of the seventh lens to the total effective focal length of the optical system, the seventh lens can possess positive focal power in the cemented doublet, facilitating apochromatization of the optical system and achieving infrared confocality.

[0063] In an exemplary embodiment, the effective focal length F8 of the eighth lens and the total effective focal length F of the optical system can satisfy the following relationship: -0.3 ≤ F8 / F ≤ -0.1. Properly configuring the ratio of the effective focal length of the eighth lens to the total effective focal length of the optical system enables the eighth lens to have negative focal power in a doublet. In combination with the seventh lens, it can achieve apochromatism, thereby achieving high image quality for the optical system.

[0064] In an exemplary embodiment, the effective focal length F9 of the ninth lens element and the total effective focal length F of the optical system may satisfy the following relationship: -1.0 ≤ F9 / F ≤ -0.5. Properly configuring the ratio of the effective focal length of the ninth lens element to the total effective focal length of the optical system can impart negative optical power to the ninth lens element, effectively reducing the overall optical length of the optical system and thereby miniaturizing the optical system.

[0065] In an exemplary embodiment, the combined focal length F78 of the seventh and eighth lenses and the total effective focal length F of the optical system may satisfy the following relationship: 0.6 ≤ F78 / F ≤ 1.1. Properly configuring the ratio of the combined focal length of the seventh and eighth lenses to the total effective focal length of the optical system allows for a reasonable distribution of the focal lengths of the seventh and eighth lenses, effectively correcting residual chromatic aberration of the optical system and achieving high image quality.

[0066] In an exemplary embodiment, the combined focal length FG1 of the first through sixth lenses and the total effective focal length F of the optical system can satisfy the following relationship: 0.9 ≤ FG1 / F ≤ 1.1. Properly configuring the ratio of the combined focal length of the first through sixth lenses to the total effective focal length of the optical system can ensure a positive focal length for the lens group formed by the first through sixth lenses, effectively reducing the overall optical length of the optical system and thereby miniaturizing the optical system.

[0067] In an exemplary embodiment, the combined focal length FG2 of the seventh through ninth lenses and the total effective focal length F of the optical system can satisfy the following relationship: -8.0 ≤ FG2 / F ≤ -2.5. Properly configuring the ratio of the combined focal length of the seventh through ninth lenses to the total effective focal length of the optical system enables the focal length of the lens group formed by the seventh through ninth lenses to be negative, effectively correcting residual chromatic aberration of the optical system and achieving high image quality.

[0068] In an exemplary embodiment, the Abbe number VD2 of the second lens may satisfy: 65≤VD2≤75. Properly configuring the Abbe number of the second lens can reduce chromatic aberration, lower the difficulty of chromatic aberration correction in the optical system, and facilitate infrared confocalization of the optical system.

[0069] In an exemplary embodiment, the Abbe number VD4 of the fourth lens element may satisfy: 65≤VD4≤75. Properly configuring the Abbe number of the fourth lens element can reduce chromatic aberration, lower the difficulty of chromatic aberration correction in the optical system, and facilitate infrared confocalization of the optical system.

[0070] In an exemplary embodiment, the Abbe number VD6 of the sixth lens element may satisfy: 90≤VD6≤100. Properly configuring the Abbe number of the sixth lens element can reduce chromatic aberration, lower the difficulty of chromatic aberration correction in the optical system, and facilitate infrared confocalization of the optical system.

[0071] The optical system according to the above-described embodiment of the present application can utilize multiple lenses, such as the nine lenses described above. By rationally allocating optical parameters such as the focal power, surface shape, center thickness of each lens, and on-axis spacing between lenses, it is possible to achieve at least one of miniaturization, long focus, high image quality, and infrared confocality. The optical system provided by the present application has excellent infrared confocality and good imaging quality at night, meeting the requirements of nighttime observation. The optical system can, for example, provide 4K high-quality images.

[0072] Those skilled in the art should understand that the total optical length TTL of the optical system used above refers to the on-axis distance from the object side surface of the first lens element to the imaging plane; and the back focal length BFL of the optical system refers to the on-axis distance from the image side surface of the ninth lens element to the imaging plane.

[0073] However, it should be understood by those skilled in the art that, without departing from the technical solution claimed in the present application, the number of lenses constituting the optical system can be changed to obtain the various results and advantages described in this specification.

[0074] Specific embodiments of the optical system applicable to the above-mentioned embodiments will be further described below with reference to the accompanying drawings.

[0075] Example 1

[0076] The following reference Figure 1 An optical system according to Example 1 of the present application is described. Figure 1 Schematic diagram of the structure of the optical system according to Example 1 of the present application.

[0077] like Figure 1 As shown, the optical system includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a ninth lens L9. A stop STO is disposed between the first lens L1 and the second lens L2. The second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are cemented to form a cemented lens, such as a quadruple. The seventh lens L7 and the eighth lens L8 are cemented to form a cemented lens, such as a doublet.

[0078] The first lens L1 has positive refractive power, its object-side surface S1 is convex, and its image-side surface S2 is concave.

[0079] The second lens L2 has positive refractive power, its object-side surface S4 is convex, and its image-side surface is concave.

[0080] The third lens L3 has negative refractive power, its object-side surface S5 is convex, and its image-side surface is concave.

[0081] The fourth lens L4 has positive refractive power, and its object-side surface S6 is convex and its image-side surface is convex.

[0082] The fifth lens L5 has negative refractive power, and its object-side surface S7 and image-side surface S8 are concave.

[0083] The sixth lens L6 has positive refractive power, its object-side surface S9 is convex, and its image-side surface S10 is concave.

[0084] The seventh lens L7 has positive refractive power, and its object-side surface S11 and image-side surface are convex.

[0085] The eighth lens L8 has negative refractive power, and its object-side surface S12 and image-side surface S13 are concave.

[0086] The ninth lens L9 has negative refractive power, its object-side surface S14 is concave, and its image-side surface S15 is convex.

[0087] A filter CG may also be provided between the ninth lens L9 and the imaging surface IMA. The filter CG has an object-side surface S16 and an image-side surface S17. Light from the object sequentially passes through the surfaces S1-S2, S4-S17 and is finally imaged on the imaging surface IMA. It should be noted that the surfaces S1-S2, S4-S17 are Figure 1 Not shown.

[0088] Table 1 shows the basic parameters of the optical system of Example 1, wherein the units of curvature radius, thickness / distance and focal length are all millimeters (mm).

[0089]

[0090] Table 1

[0091] In this embodiment, the total optical length TTL of the optical system is 54.53 mm, the aperture value FNO of the optical system is 2.2, and the total effective focal length F of the optical system is 60 mm.

[0092] Example 2

[0093] The following reference Figure 2 An optical system according to Example 2 of the present application is described. Figure 2 Schematic diagram of the structure of the optical system according to Example 2 of the present application.

[0094] like Figure 2As shown, the optical system includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a ninth lens L9. A stop STO is disposed between the first lens L1 and the second lens L2. The second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are cemented to form a cemented lens, such as a quadruple. The seventh lens L7 and the eighth lens L8 are cemented to form a cemented lens, such as a doublet.

[0095] The first lens L1 has positive refractive power, its object-side surface S1 is convex, and its image-side surface S2 is concave.

[0096] The second lens L2 has positive refractive power, its object-side surface S4 is convex, and its image-side surface is concave.

[0097] The third lens L3 has negative refractive power, its object-side surface S5 is convex, and its image-side surface is concave.

[0098] The fourth lens L4 has positive refractive power, and its object-side surface S6 is convex and its image-side surface is convex.

[0099] The fifth lens L5 has negative refractive power, and its object-side surface S7 and image-side surface S8 are concave.

[0100] The sixth lens L6 has positive refractive power, its object-side surface S9 is convex, and its image-side surface S10 is concave.

[0101] The seventh lens L7 has positive refractive power, and its object-side surface S11 and image-side surface are convex.

[0102] The eighth lens L8 has negative refractive power, and its object-side surface S12 and image-side surface S13 are concave.

[0103] The ninth lens L9 has negative refractive power, its object-side surface S14 is concave, and its image-side surface S15 is convex.

[0104] A filter CG may also be provided between the ninth lens L9 and the imaging surface IMA. The filter CG has an object-side surface S16 and an image-side surface S17. Light from the object sequentially passes through the surfaces S1-S2, S4-S17 and is finally imaged on the imaging surface IMA. It should be noted that the surfaces S1-S2, S4-S17 are Figure 2 Not shown.

[0105] Table 2 shows the basic parameters of the optical system of Example 2, wherein the units of curvature radius, thickness / distance and focal length are all millimeters (mm).

[0106]

[0107] Table 2

[0108] In this embodiment, the total optical length TTL of the optical system is 54.67 mm, the aperture value FNO of the optical system is 2.2, and the total effective focal length F of the optical system is 60 mm.

[0109] Example 3

[0110] The following reference Figure 3 An optical system according to Example 3 of the present application is described. Figure 3 Schematic diagram of the structure of the optical system according to Example 3 of the present application.

[0111] like Figure 3 As shown, the optical system includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a ninth lens L9. A stop STO is disposed between the first lens L1 and the second lens L2. The second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are cemented to form a cemented lens, such as a quadruple. The seventh lens L7 and the eighth lens L8 are cemented to form a cemented lens, such as a doublet.

[0112] The first lens L1 has positive refractive power, its object-side surface S1 is convex, and its image-side surface S2 is concave.

[0113] The second lens L2 has positive refractive power, its object-side surface S4 is convex, and its image-side surface is concave.

[0114] The third lens L3 has negative refractive power, its object-side surface S5 is convex, and its image-side surface is concave.

[0115] The fourth lens L4 has positive refractive power, its object-side surface S6 is convex, and its image-side surface is concave.

[0116] The fifth lens L5 has negative refractive power, its object-side surface S7 is convex, and its image-side surface S8 is concave.

[0117] The sixth lens L6 has positive refractive power, its object-side surface S9 is convex, and its image-side surface S10 is concave.

[0118] The seventh lens L7 has positive refractive power, and its object-side surface S11 and image-side surface are convex.

[0119] The eighth lens L8 has negative refractive power, and its object-side surface S12 and image-side surface S13 are concave.

[0120] The ninth lens L9 has negative refractive power, its object-side surface S14 is concave, and its image-side surface S15 is convex.

[0121] A filter CG may also be provided between the ninth lens L9 and the imaging surface IMA. The filter CG has an object-side surface S16 and an image-side surface S17. Light from the object sequentially passes through the surfaces S1-S2, S4-S17 and is finally imaged on the imaging surface IMA. It should be noted that the surfaces S1-S2, S4-S17 are Figure 3 Not shown.

[0122] Table 3 shows the basic parameters of the optical system of Example 3, wherein the units of curvature radius, thickness / distance and focal length are all millimeters (mm).

[0123]

[0124] Table 3

[0125] In this embodiment, the total optical length TTL of the optical system is 55 mm, the aperture value FNO of the optical system is 2.2, and the total effective focal length F of the optical system is 60 mm.

[0126] Example 4

[0127] The following reference Figure 4 An optical system according to Example 4 of the present application is described. Figure 4 Schematic diagram of the structure of the optical system according to Example 4 of the present application.

[0128] like Figure 4 As shown, the optical system includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a ninth lens L9. A stop STO is disposed between the first lens L1 and the second lens L2. The second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are cemented to form a cemented lens, such as a quadruple. The seventh lens L7 and the eighth lens L8 are cemented to form a cemented lens, such as a doublet.

[0129] The first lens L1 has positive refractive power, its object-side surface S1 is convex, and its image-side surface S2 is concave.

[0130] The second lens L2 has positive refractive power, its object-side surface S4 is convex, and its image-side surface is concave.

[0131] The third lens L3 has negative refractive power, its object-side surface S5 is convex, and its image-side surface is concave.

[0132] The fourth lens L4 has positive refractive power, its object-side surface S6 is convex, and its image-side surface is concave.

[0133] The fifth lens L5 has negative refractive power, its object-side surface S7 is convex, and its image-side surface S8 is concave.

[0134] The sixth lens L6 has positive refractive power, its object-side surface S9 is convex, and its image-side surface S10 is concave.

[0135] The seventh lens L7 has positive refractive power, and its object-side surface S11 and image-side surface are convex.

[0136] The eighth lens L8 has negative refractive power, and its object-side surface S12 and image-side surface S13 are concave.

[0137] The ninth lens L9 has negative refractive power, its object-side surface S14 is concave, and its image-side surface S15 is convex.

[0138] A filter CG may also be provided between the ninth lens L9 and the imaging surface IMA. The filter CG has an object-side surface S16 and an image-side surface S17. Light from the object sequentially passes through the surfaces S1-S2, S4-S17 and is finally imaged on the imaging surface IMA. It should be noted that the surfaces S1-S2, S4-S17 are Figure 4 Not shown.

[0139] Table 4 shows the basic parameters of the optical system of Example 4, wherein the units of curvature radius, thickness / distance and focal length are all millimeters (mm).

[0140]

[0141] Table 4

[0142] In this embodiment, the total optical length TTL of the optical system is 55 mm, the aperture value FNO of the optical system is 2.2, and the total effective focal length F of the optical system is 60 mm.

[0143] Example 5

[0144] The following reference Figure 5 An optical system according to Example 5 of the present application is described. Figure 5 Schematic diagram of the structure of the optical system according to Example 5 of the present application.

[0145] like Figure 5As shown, the optical system includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a ninth lens L9. A stop STO is disposed between the first lens L1 and the second lens L2. The second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are cemented to form a cemented lens, such as a quadruple. The seventh lens L7 and the eighth lens L8 are cemented to form a cemented lens, such as a doublet.

[0146] The first lens L1 has positive refractive power, its object-side surface S1 is convex, and its image-side surface S2 is concave.

[0147] The second lens L2 has positive refractive power, its object-side surface S4 is convex, and its image-side surface is concave.

[0148] The third lens L3 has negative refractive power, its object-side surface S5 is convex, and its image-side surface is concave.

[0149] The fourth lens L4 has positive refractive power, its object-side surface S6 is convex, and its image-side surface is concave.

[0150] The fifth lens L5 has negative refractive power, its object-side surface S7 is convex, and its image-side surface S8 is concave.

[0151] The sixth lens L6 has positive refractive power, its object-side surface S9 is convex, and its image-side surface S10 is concave.

[0152] The seventh lens L7 has positive refractive power, and its object-side surface S11 and image-side surface are convex.

[0153] The eighth lens L8 has negative refractive power, and its object-side surface S12 and image-side surface S13 are concave.

[0154] The ninth lens L9 has negative refractive power, its object-side surface S14 is concave, and its image-side surface S15 is convex.

[0155] A filter CG may also be provided between the ninth lens L9 and the imaging surface IMA. The filter CG has an object-side surface S16 and an image-side surface S17. Light from the object sequentially passes through the surfaces S1-S2, S4-S17 and is finally imaged on the imaging surface IMA. It should be noted that the surfaces S1-S2, S4-S17 are Figure 5 Not shown.

[0156] Table 5 shows the basic parameters of the optical system of Example 5, wherein the units of curvature radius, thickness / distance and focal length are all millimeters (mm).

[0157]

[0158]

[0159] Table 5

[0160] In this embodiment, the total optical length TTL of the optical system is 55 mm, the aperture value FNO of the optical system is 2.2, and the total effective focal length F of the optical system is 60 mm.

[0161] In summary, the conditional expressions in Examples 1 to 5 satisfy the relationship shown in Table 6.

[0162] Conditional formula / Example 1 2 3 4 5 TTL / F 0.908 0.911 0.917 0.917 0.917 Dmax / TTL 0.253 0.252 0.251 0.251 0.251 BFL / F 0.190 0.194 0.200 0.190 0.197 F2345 / F -0.557 -0.565 -0.570 -0.618 -0.608 F1 / F 0.802 0.806 0.909 0.907 0.915 F2 / F 0.859 0.862 0.783 0.806 0.799 F3 / F -0.333 -0.333 -0.370 -0.377 -0.337 F4 / F 0.305 0.306 0.340 0.347 0.323 F5 / F -0.254 -0.257 -0.235 -0.241 -0.261 F6 / F 0.764 0.770 0.661 0.663 0.717 F7 / F 0.158 0.163 0.173 0.174 0.177 F8 / F -0.200 -0.206 -0.209 -0.210 -0.212 F9 / F -0.530 -0.544 -0.872 -0.811 -0.807 F78 / F 0.674 0.699 0.927 0.980 0.970 FG1 / F 0.993 0.992 0.993 0.976 0.980 FG2 / F -3.308 -3.280 -7.769 -5.144 -6.225 VD2 68.3 68.3 68.3 68.3 68.3 VD4 68.3 68.3 68.3 68.3 68.3 VD6 94.5 94.5 94.5 94.5 94.5

[0163] Table 6

[0164] 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) element, and the imaging device is equipped with the optical system described above.

[0165] 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 utility model disclosed in this application 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 with similar functions disclosed in this application.

Claims

1. An optical system, characterized in that Along the optical axis from the object side to the image side, they include: a first lens having positive optical power; a second lens having positive optical power; a third lens having negative optical power; a fourth lens element having positive optical power; a fifth lens having negative optical power; a sixth lens element having positive optical power, whose object-side surface is convex and whose image-side surface is concave; a seventh lens having positive optical power; an eighth lens having negative optical power; and a ninth lens element having negative optical power; The optical system includes nine lenses having optical power.

2. The optical system according to claim 1, wherein The object side surface of the first lens is convex, 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 concave; The object-side surface of the fourth lens is convex, and the image-side surface is convex or concave; The object-side surface of the fifth lens is convex or concave, and the image-side surface is concave; The object-side surface of the seventh lens is convex, and the image-side surface is convex; The object-side surface of the eighth lens is concave, and the image-side surface is concave; The object-side surface of the ninth lens is concave, and the image-side surface is convex.

3. The optical system according to claim 1 or 2, wherein: The total effective focal length F of the optical system and the total optical length TTL of the optical system satisfy the following: 0.8≤TTL / F≤1.

0.

4. The optical system according to claim 1 or 2, wherein: The maximum full aperture Dmax of the optical system and the total optical length TTL of the optical system satisfy the following conditions: 0.2≤Dmax / TTL≤0.

4.

5. The optical system according to claim 1 or 2, wherein: The back focal length BFL of the optical system and the total effective focal length F of the optical system satisfy the following: 0.1≤BFL / F≤0.

3.

6. The optical system according to claim 1 or 2, wherein: The second lens, the third lens, the fourth lens and the fifth lens are cemented to form a cemented lens; the combined focal length F2345 of the second lens, the third lens, the fourth lens and the fifth lens and the total effective focal length F of the optical system satisfy: -0.7≤F2345 / F≤-0.

5.

7. The optical system according to claim 1 or 2, wherein: The effective focal length F1 of the first lens and the total effective focal length F of the optical system satisfy the following: 0.7≤F1 / F≤1.

0.

8. The optical system according to claim 1 or 2, wherein: The effective focal length F2 of the second lens and the total effective focal length F of the optical system satisfy the following: 0.7≤F2 / F≤1.

0.

9. The optical system according to claim 1 or 2, wherein: The effective focal length F3 of the third lens and the total effective focal length F of the optical system satisfy the following: -0.5≤F3 / F≤-0.

2.

10. The optical system according to claim 1 or 2, wherein: The effective focal length F4 of the fourth lens and the total effective focal length F of the optical system satisfy the following: 0.3≤F4 / F≤0.

5.

11. The optical system according to claim 1 or 2, wherein: The effective focal length F5 of the fifth lens and the total effective focal length F of the optical system satisfy the following: -0.4≤F5 / F≤-0.

2.

12. The optical system according to claim 1 or 2, wherein: The effective focal length F6 of the sixth lens and the total effective focal length F of the optical system satisfy the following: 0.6≤F6 / F≤0.

9.

13. The optical system according to claim 1 or 2, wherein: The effective focal length F7 of the seventh lens and the total effective focal length F of the optical system satisfy the following: 0.1≤F7 / F≤0.

3.

14. The optical system according to claim 1 or 2, wherein: The effective focal length F8 of the eighth lens and the total effective focal length F of the optical system satisfy the following: -0.3≤F8 / F≤-0.

1.

15. The optical system according to claim 1 or 2, wherein: The effective focal length F9 of the ninth lens and the total effective focal length F of the optical system satisfy the following: -1.0≤F9 / F≤-0.

5.

16. The optical system according to claim 1 or 2, wherein: The seventh lens and the eighth lens are cemented together to form a cemented lens; the combined focal length F78 of the seventh lens and the eighth lens and the total effective focal length F of the optical system satisfy the following: 0.6≤F78 / F≤1.

1.

17. The optical system according to claim 1 or 2, wherein: A combined focal length FG1 of the first to sixth lenses and a total effective focal length F of the optical system satisfy the following: 0.9≤FG1 / F≤1.

1.

18. The optical system according to claim 1 or 2, wherein: A combined focal length FG2 of the seventh to ninth lenses and a total effective focal length F of the optical system satisfy the following: -8.0≤FG2 / F≤-2.

5.

19. The optical system according to claim 1 or 2, wherein: The optical system satisfies at least one of the following conditional expressions: 65≤VD2≤75, 65≤VD4≤75, 90≤VD6≤100, Wherein, VD2 is the Abbe number of the second lens, VD4 is the Abbe number of the fourth lens, and VD6 is the Abbe number of the sixth lens.

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