Optical system

Abstract

The application provides an optical system, which comprises a lens group and an imaging lens in sequence from an object side to an image side along an optical axis; the lens group comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens and a fourteenth lens arranged in sequence from the object side to the image side along the optical axis; wherein the first lens is cemented with the second lens, the third lens is cemented with the fourth lens, the seventh lens is cemented with the eighth lens, the ninth lens is cemented with the tenth lens, and the eleventh lens is cemented with the twelfth lens. The optical system also satisfies: 0.36≤F12 / |F34|≤1.65; 0.09≤F1112 / |F910|≤1.57; and 3.35≤TD / (T23+T45)<3.90.

Description

Technical Field

[0001] This application relates to the field of optical device technology, and in particular to an optical system. Background Technology

[0002] With the rapid development of smartphone photography capabilities, multi-camera modules have become standard, with telephoto lenses being crucial for achieving distant shooting and a sense of spatial compression. However, due to the extremely limited physical space of smartphones, the optical zoom capability of their built-in periscope telephoto lenses is usually limited to between 3x and 5x, making it difficult to meet users' needs for higher-quality zoom shooting at greater distances.

[0003] Teleconverters (or external lenses) break through this physical limitation: these lenses can be attached to the front of the main camera or telephoto lens of a mobile phone. By introducing an additional set of optical lenses, the focal length of the entire optical system is effectively extended, thereby achieving a higher optical zoom multiplication effect and extending the telephoto capability of the mobile phone to 10x or even higher.

[0004] However, existing teleconverters face the problem of matching with the original telephoto lens of a mobile phone: the original telephoto lens of a mobile phone itself has a complex optical system, and if the external teleconverter cannot be fully matched with the original telephoto lens of the mobile phone, it will introduce serious aberration deterioration, vignetting or hot spot problems; moreover, the teleconverter itself also has the problem of balancing miniaturization and high performance: as an external accessory, its size must be small and portable enough, but this contradicts the complex optical structure of multiple elements required to achieve high resolution and high contrast imaging. Summary of the Invention

[0005] This application provides an optical system including a lens group, which comprises, along the optical axis from the object side to the image side, the following components in sequence: a first lens with positive optical power, wherein the object side and the image side of the first lens are convex; a second lens with negative optical power, wherein the object side of the second lens is concave; a third lens with positive optical power, wherein the object side and the image side of the third lens are convex; and a fourth lens with negative optical power, wherein the object side and the image side of the fourth lens are concave; and a lens with positive optical power... Fifth lens; a sixth lens having positive or negative optical power, wherein the object-side surface of the sixth lens is convex and the image-side surface of the sixth lens is concave; a seventh lens having positive optical power; an eighth lens having negative optical power; a ninth lens having positive optical power, wherein the image-side surface of the ninth lens is convex; a tenth lens having positive or negative optical power, wherein the object-side surface of the tenth lens is concave and the image-side surface of the tenth lens is convex; an eleventh lens having negative optical power, wherein the image-side surface of the eleventh lens is concave; a twelfth lens having positive optical power, wherein the twelfth lens... The object-side surface of the lens is convex, and the image-side surface of the twelfth lens is convex; a thirteenth lens has positive or negative optical power; a fourteenth lens has positive optical power; wherein the first and second lenses are cemented together, the third and fourth lenses are cemented together, the ninth and tenth lenses are cemented together, and the eleventh and twelfth lenses are cemented together; and the optical system satisfies: 0.36≤F12 / |F34|≤1.65; 0.09≤F1112 / |F910|≤1.57; 3.35≤TD / (T23+T4) 5) < 3.90; where F12 is the combined focal length of the first lens and the second lens, F34 is the combined focal length of the third lens and the fourth lens, F1112 is the combined focal length of the eleventh lens and the twelfth lens, F910 is the combined focal length of the ninth lens and the tenth lens, TD is the distance on the optical axis from the object side of the first lens to the image side of the fourteenth lens, T23 is the air gap on the optical axis between the second lens and the third lens, and T45 is the air gap on the optical axis between the fourth lens and the fifth lens.

[0006] In some embodiments, the seventh lens and the eighth lens are cemented together, and the optical system satisfies: -7.20 < F78 / (CT7+CT8) < -2.65; where F78 is the combined focal length of the seventh lens and the eighth lens, CT7 is the center thickness of the seventh lens, and CT8 is the center thickness of the eighth lens.

[0007] In some embodiments, the optical system satisfies: 3.70 < f1 / CT1 < 5.45; where f1 is the effective focal length of the first lens and CT1 is the center thickness of the first lens.

[0008] In some embodiments, the optical system satisfies: 0.55 < (CT9 + CT10) / (CT11 + CT12) < 1.95; where CT9 is the center thickness of the ninth lens, CT10 is the center thickness of the tenth lens, CT11 is the center thickness of the eleventh lens, and CT12 is the center thickness of the twelfth lens.

[0009] In some embodiments, the optical system satisfies: -2.40 < R24 / f12 ≤ -1.45; where R24 is the radius of curvature of the image-side surface of the twelfth lens, and f12 is the effective focal length of the twelfth lens.

[0010] In some embodiments, the optical system satisfies: 0.40 < F1112 / (f13+f14) < 3.75; where F1112 is the combined focal length of the eleventh lens and the twelfth lens, f13 is the effective focal length of the thirteenth lens, and f14 is the effective focal length of the fourteenth lens.

[0011] In some embodiments, the optical system satisfies: 2.40 < R5 / (CT3+CT4) < 5.50; where R5 is the radius of curvature of the object side of the third lens, CT3 is the center thickness of the third lens, and CT4 is the center thickness of the fourth lens.

[0012] In some embodiments, the optical system satisfies: 0.25 < F1314 / F56 < 1.35; where F1314 is the combined focal length of the thirteenth lens and the fourteenth lens, and F56 is the combined focal length of the fifth lens and the sixth lens.

[0013] In some embodiments, the optical system satisfies: 1.05 < ∑CT / |F1314| ≤ 2.20; where ∑CT is the sum of the center thicknesses of all lenses from the first lens to the fourteenth lens, and F1314 is the combined focal length of the thirteenth lens and the fourteenth lens.

[0014] In some embodiments, the optical system satisfies: 1.65 < (N3 + N4) / N5 < 1.95; where N3 is the refractive index of the third lens, N4 is the refractive index of the fourth lens, and N5 is the refractive index of the fifth lens.

[0015] In some embodiments, the optical system satisfies: 0.95 < (V11 + V12) / (V9 + V10) < 1.60; where V11 is the Abbe number of the eleventh lens, V12 is the Abbe number of the twelfth lens, V9 is the Abbe number of the ninth lens, and V10 is the Abbe number of the tenth lens.

[0016] In some embodiments, the optical system satisfies: -3.85 < (f2 + f4) / f3 < -1.60; where f2 is the effective focal length of the second lens, f4 is the effective focal length of the fourth lens, and f3 is the effective focal length of the third lens.

[0017] In some embodiments, the optical system satisfies: 0.96≤|(f7 / f8)×(f9 / f10)|≤1.95; where f7 is the effective focal length of the seventh lens, f8 is the effective focal length of the eighth lens, f9 is the effective focal length of the ninth lens, and f10 is the effective focal length of the tenth lens.

[0018] In some embodiments, the optical system satisfies: -1.85 < f11 / R22 < -0.50; where f11 is the effective focal length of the eleventh lens and R22 is the radius of curvature of the image-side surface of the eleventh lens.

[0019] In some embodiments, the optical system satisfies: -11.65 < f / (CT5+CT6) < -5.70; where f is the effective focal length of the optical system, CT5 is the center thickness of the fifth lens, and CT6 is the center thickness of the sixth lens.

[0020] In some embodiments, the optical system further includes an imaging lens and an imaging surface located on the image side of the fourteenth lens, wherein the outgoing light beam from the lens group enters the imaging lens to image on the imaging surface using the imaging lens.

[0021] In summary, by rationally configuring this optical system, with parameters of 0.36≤F12 / |F34|≤1.65, 0.09≤F1112 / |F910|≤1.57, and 3.35≤TD / (T23+T45)<3.90, it is ensured that the teleconverter lens, while introducing high magnification, can also function as an independent aberration correction unit. This unit pre-corrects and compensates for key aberrations such as axial chromatic aberration, field curvature, and astigmatism before the light enters the phone's native lens. This avoids transmitting severe residual aberrations to the phone's lens, thus guaranteeing high resolution and consistency in the final synthesized image from the center to the edges. Simultaneously, this structural constraint allows the teleconverter lens's exit pupil position and image plane curvature to achieve a good match with the phone's native telephoto lens's entrance pupil and image plane characteristics, effectively suppressing vignetting, fading, and edge image quality degradation caused by optical interface mismatch. Together, these factors ensure that this teleconverter achieves high zoom ratio, excellent image quality, and high compatibility with mobile phone lenses within a compact size. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall architecture of the optical system in one embodiment of this application;

[0023] Figure 2 This is a schematic diagram of the lens assembly according to Embodiment 1 of this application;

[0024] Figure 3 The astigmatism curve of the optical system in Example 1 is shown.

[0025] Figure 4 This is a distortion curve diagram of the optical system in Example 1;

[0026] Figure 5 The magnification chromatic aberration curve of the optical system in Example 1;

[0027] Figure 6 This is a schematic diagram of the lens assembly according to Embodiment 2 of this application;

[0028] Figure 7 This is an astigmatism curve diagram of the optical system in Example 2;

[0029] Figure 8 This is a distortion curve diagram of the optical system in Example 2;

[0030] Figure 9 This is a magnification chromatic aberration curve of the optical system in Example 2;

[0031] Figure 10 This is a schematic diagram of the lens assembly according to Embodiment 3 of this application;

[0032] Figure 11 This is an astigmatism curve diagram of the optical system in Example 3;

[0033] Figure 12 This is a distortion curve diagram of the optical system in Example 3;

[0034] Figure 13 This is a magnification chromatic aberration curve of the optical system in Example 3;

[0035] Figure 14 This is a schematic diagram of the lens assembly according to Embodiment 4 of this application;

[0036] Figure 15 This is an astigmatism curve diagram of the optical system in Example 4;

[0037] Figure 16 This is a distortion curve diagram of the optical system in Example 4;

[0038] Figure 17 This is a magnification chromatic aberration curve of the optical system in Example 4;

[0039] Figure 18 This is a schematic diagram of the lens assembly according to Embodiment 5 of this application;

[0040] Figure 19 This is an astigmatism curve diagram of the optical system in Example 5;

[0041] Figure 20 This is a distortion curve diagram of the optical system in Example 5;

[0042] Figure 21 This is a magnification chromatic aberration curve of the optical system in Example 5.

[0043] Figure label:

[0044] 10. Lens group; 20. Imaging lens; E1. First lens; E2. Second lens; E3. Third lens; E4. Fourth lens; E5. Fifth lens; E6. Sixth lens; E7. Seventh lens; E8. Eighth lens; E9. Ninth lens; E10. Tenth lens; E11. Eleventh lens; E12. Twelfth lens; E13. Thirteenth lens; E14. Fourteenth lens. Detailed Implementation

[0045] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0046] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of this application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0047] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0048] In this paper, the paraxial region refers to the area near the optical axis. If the lens surface is convex and its location is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and its location is not defined, it means that the lens surface is concave at least in the paraxial region. The surface shape in the paraxial region can be determined based on the sign of the R value (R refers to the radius of curvature of the paraxial region). For the object side, a positive R value indicates a convex surface, and a negative R value indicates a concave surface; for the image side, a positive R value indicates a concave surface, and a negative R value indicates a convex surface.

[0049] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0050] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having a meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formalized sense, unless expressly so specified herein.

[0051] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. The following embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this application. It should be pointed out that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0052] Please see Figure 1 , Figure 1 A schematic diagram of the overall architecture of the optical system in one embodiment of this application.

[0053] This application provides an optical system including a lens group, which comprises, along the optical axis from the object side to the image side, the following components in sequence: a first lens E1 with positive optical power, wherein the object side and image side of the first lens E1 are convex; a second lens E2 with negative optical power, wherein the object side of the second lens E2 is concave; a third lens E3 with positive optical power, wherein the object side and image side of the third lens E3 are convex; a fourth lens E4 with negative optical power, wherein the object side and image side of the fourth lens E4 are concave; and a fifth lens E5 with positive optical power; A sixth lens E6 has either positive or negative optical power, wherein the object-side surface of the sixth lens E6 is convex and the image-side surface of the sixth lens E6 is concave; a seventh lens E7 has positive optical power; an eighth lens E8 has negative optical power; a ninth lens E9 has positive optical power, wherein the image-side surface of the ninth lens E9 is convex; a tenth lens E10 has either positive or negative optical power, wherein the object-side surface of the tenth lens E10 is concave and the image-side surface of the tenth lens E10 is convex; an eleventh lens E11 has negative optical power, wherein the image-side surface of the eleventh lens E11 is concave; and a twelfth lens E12 has positive optical power. The object-side surface of the twelfth lens E12 is convex, and the image-side surface of the twelfth lens E12 is also convex; the thirteenth lens E13 has positive or negative optical power; the fourteenth lens E14 has positive optical power; wherein, the first lens E1 and the second lens E2 are cemented together, the third lens E3 and the fourth lens E4 are cemented together, the ninth lens E9 and the tenth lens E10 are cemented together, and the eleventh lens E11 and the twelfth lens E12 are cemented together; and the optical system satisfies: 0.36≤F12 / |F34|≤1.65; 0.09≤F1112 / |F910|≤1.57; 3.35≤TD / (T23+T45)< 3.90; where F12 is the combined focal length of the first lens E1 and the second lens E2, F34 is the combined focal length of the third lens E3 and the fourth lens E4, F1112 is the combined focal length of the eleventh lens E11 and the twelfth lens E12, F910 is the combined focal length of the ninth lens E9 and the tenth lens E10, TD is the distance on the optical axis from the object side of the first lens E1 to the image side of the fourteenth lens E14, T23 is the air gap on the optical axis between the second lens E2 and the third lens E3, and T45 is the air gap on the optical axis between the fourth lens E4 and the fifth lens E5.

[0054] By rationally configuring this optical system, with parameters of 0.36≤F12 / |F34|≤1.65, 0.09≤F1112 / |F910|≤1.57, and 3.35≤TD / (T23+T45)<3.90, the teleconverter lens can function as an independent aberration correction unit while introducing high magnification. It pre-corrects and compensates for key aberrations such as axial chromatic aberration, field curvature, and astigmatism before light enters the phone's native lens. This avoids transmitting severe residual aberrations to the phone's lens, thus ensuring high resolution and consistency in the final synthesized image from the center to the edges. Simultaneously, this structural constraint allows the teleconverter lens's exit pupil position and image plane curvature to be well-matched with the phone's native telephoto lens's entrance pupil and image plane characteristics, effectively suppressing vignetting, fading, and edge image quality degradation caused by optical interface mismatch. Together, these factors ensure that this teleconverter achieves high zoom ratio, excellent image quality, and high compatibility with mobile phone lenses within a compact size.

[0055] In some embodiments, the seventh lens E7 and the eighth lens E8 are cemented together, and the optical system satisfies: -7.20 < F78 / (CT7+CT8) < -2.65; where F78 is the combined focal length of the seventh lens E7 and the eighth lens E8, CT7 is the center thickness of the seventh lens E7, and CT8 is the center thickness of the eighth lens E8. The seventh lens E7 and the eighth lens E8, as a negative optical power cemented group, are mainly responsible for optical path refraction and aberration compensation in the teleconverter. Reasonably controlling this conditional range can effectively suppress barrel or pincushion distortion while achieving magnification. Linking the optical power of the lens to its physical thickness avoids using overly curved and fragile lenses in pursuit of optical performance, thus improving the durability and yield of this teleconverter.

[0056] In some embodiments, the optical system satisfies: 3.70 < f1 / CT1 < 5.45; where f1 is the effective focal length of the first lens E1, and CT1 is the center thickness of the first lens E1. By reasonably controlling this conditional range, it ensures that the first lens E1 with positive optical power has sufficient optical power to effectively converge light, while constraining the center thickness of the first lens E1 to be not too small, so that the first lens E1 has basic mechanical strength to resist accidental scratches and impacts. At the same time, this ratio optimizes the shape of the first lens E1, suppresses its spherical aberration, and helps improve subsequent optical performance.

[0057] In some embodiments, the optical system satisfies: 0.55 < (CT9 + CT10) / (CT11 + CT12) < 1.95; where CT9 is the center thickness of the ninth lens E9, CT10 is the center thickness of the tenth lens E10, CT11 is the center thickness of the eleventh lens E11, and CT12 is the center thickness of the twelfth lens E12. Reasonably controlling this conditional range ensures a stable center of gravity for the lens group, avoiding a top-heavy design and improving the feel when holding the device. Simultaneously, when the ambient temperature changes, the similar thicknesses of the four lenses help compensate for the thermal expansion and contraction effects of different lens groups, maintaining stable optical performance and ensuring coordinated operation between the lens groups.

[0058] In some embodiments, the optical system satisfies: -2.40 < R24 / f12 ≤ -1.45; where R24 is the radius of curvature of the image-side surface of the twelfth lens E12, and f12 is the effective focal length of the twelfth lens E12. This condition effectively controls the shape of the image-side surface of the twelfth lens E12, which is close to the image plane and is extremely sensitive to astigmatism. By constraining the relationship between the curvature of this surface and the lens focal length, the meridional and sagittal field curvatures can be efficiently balanced, ensuring a sharp point image in both the central and peripheral fields of view. Simultaneously, it simplifies the mechanical structure design, helps improve the stability and durability of the system, and reduces manufacturing costs.

[0059] In some embodiments, the optical system satisfies: 0.40 < F1112 / (f13+f14) < 3.75; where F1112 is the combined focal length of the eleventh lens E11 and the twelfth lens E12, f13 is the effective focal length of the thirteenth lens E13, and f14 is the effective focal length of the fourteenth lens E14. This condition controls the power distribution between the cemented group and the last two individual lenses at the end of the teleconverter. It ensures a smooth transition of power from the cemented group to the individual lenses, which is crucial for achieving good image uniformity. It avoids advanced aberrations caused by abrupt changes in power, thus guaranteeing consistent image quality from the center to the edges.

[0060] In some embodiments, the optical system satisfies: 2.40 < R5 / (CT3+CT4) < 5.50; where R5 is the radius of curvature of the object-side surface of the third lens E3, CT3 is the center thickness of the third lens E3, and CT4 is the center thickness of the fourth lens E4. Reasonably controlling this conditional range avoids excessively large or small curvature of the object-side surface of the third lens E3. A large or small radius of curvature increases the difficulty and cost during injection molding or grinding, leading to low yield and hindering the large-scale production of teleconverters. Simultaneously, the object-side surface of the third lens E3 is a crucial turning point in the front optical path of the lens group 10, helping to control astigmatism generated by the front lens group.

[0061] In some embodiments, the optical system satisfies: 0.25 < F1314 / F56 < 1.35; where F1314 is the combined focal length of the thirteenth lens E13 and the fourteenth lens E14, and F56 is the combined focal length of the fifth lens E5 and the sixth lens E6. Properly controlling this conditional range is crucial for achieving the negative optical power (magnification function) of the teleconverter lens. The combined focal length F1314 of the last two lenses must coordinate with this, on the one hand relaying light to the correct image plane position, and on the other hand compensating for off-axis aberrations generated by the middle lens of the lens group 10, ensuring the sharpness of the entire system's imaging.

[0062] In some embodiments, the optical system satisfies: 1.05 < ∑CT / |F1314| ≤ 2.20; where ∑CT is the sum of the center thicknesses of all lenses from the first lens E1 to the fourteenth lens E14, and F1314 is the combined focal length of the thirteenth lens E13 and the fourteenth lens E14. Reasonably controlling this conditional range reflects the achievement of the optimal "performance-to-volume" ratio while meeting the required optical performance. Simultaneously, it prevents the aberration correction capability of the rear lens group from being weakened due to excessive compression of the lens group 10's thickness, ensuring the output image quality of the teleconverter lens.

[0063] In some embodiments, the optical system satisfies: 1.65 < (N3 + N4) / N5 < 1.95; where N3 is the refractive index of the third lens E3, N4 is the refractive index of the fourth lens E4, and N5 is the refractive index of the fifth lens E5. This condition optimizes system-level aberrations by configuring the refractive indices of adjacent lenses, effectively controlling the Petzval sum of the system, obtaining a flatter image plane, and facilitating better matching with mobile phone chips.

[0064] In some embodiments, the optical system satisfies: 0.95 < (V11 + V12) / (V9 + V10) < 1.60; where V11 is the Abbe number of the eleventh lens E11, V12 is the Abbe number of the twelfth lens E12, V9 is the Abbe number of the ninth lens E9, and V10 is the Abbe number of the tenth lens E10. By reasonably controlling this conditional range, the cemented lens uses a combination of high and low Abbe number materials to correct chromatic aberration; the dispersion characteristics of the two cemented groups are coordinated at the system level, which can simultaneously and effectively suppress axial chromatic aberration and magnification chromatic aberration, meeting the requirements of apochromatic aberration.

[0065] In some embodiments, the optical system satisfies: -3.85 < (f2 + f4) / f3 < -1.60; where f2 is the effective focal length of the second lens E2, f4 is the effective focal length of the fourth lens E4, and f3 is the effective focal length of the third lens E3. By reasonably controlling this conditional range, the positive field curvature and astigmatism produced by the positive optical power of the first lens E1 and other positive lenses are effectively compensated; an optical power structure conducive to aberration balance is established at the beginning of the system, laying a solid foundation for the subsequent fine correction of the lens group 10.

[0066] In some embodiments, the optical system satisfies: 0.96 ≤ |(f7 / f8)×(f9 / f10)| ≤ 1.95; where f7 is the effective focal length of the seventh lens E7, f8 is the effective focal length of the eighth lens E8, f9 is the effective focal length of the ninth lens E9, and f10 is the effective focal length of the tenth lens E10. By reasonably controlling the range of this conditional expression, when the value of the conditional expression is close to 1, the seventh lens E7, the eighth lens E8, the ninth lens E9, and the tenth lens E10 form an approximately symmetrical structure. This enables the system to correct aberrations. Even if not perfectly symmetrical, this ratio ensures that the optical power of these lenses can compensate for each other, allowing aberrations to cancel each other out, thereby simplifying the aberration correction difficulty of the entire system.

[0067] In some embodiments, the optical system satisfies: -1.85 < f11 / R22 < -0.50; where f11 is the effective focal length of the eleventh lens E11, and R22 is the radius of curvature of the image-side surface of the eleventh lens E11. By reasonably controlling this conditional range, the curvature shape of the eleventh lens E11 is controlled. Under this curvature shape, the eleventh lens E11 can efficiently correct astigmatism and distortion generated at the rear of the system without introducing excessive other harmful aberrations.

[0068] In some embodiments, the optical system satisfies: -11.65 < f / (CT5 + CT6) < -5.70; where f is the effective focal length of the optical system, CT5 is the center thickness of the fifth lens E5, and CT6 is the center thickness of the sixth lens E6. Due to the characteristics of teleconverters, the total focal length of the system is negative, reflecting the intensity of the negative optical power allocated to the system within the physical space occupied by the fifth lens E5 and the sixth lens E6. The fifth lens E5 and the sixth lens E6 are located in the middle of the system and are crucial for realizing the teleconverting function and correcting off-axis aberrations. This ratio ensures that within a limited space, sufficient optical power can be provided to achieve the desired magnification, while reasonable lens thickness ensures the correctability of aberrations and the manufacturability of the structure.

[0069] In some embodiments, the optical system further includes an imaging lens 20 located on the image side of the fourteenth lens E14 and an imaging surface IMG, wherein the outgoing light beam of the lens group 10 enters the imaging lens 20 to image on the imaging surface IMG using the imaging lens 20.

[0070] The following describes some specific, non-limiting embodiments of the above-described embodiments of this application in more detail with reference to the accompanying drawings. For ease of description, in the following embodiments, OBJ represents the object plane of the optical system, STO represents the surface of the aperture stop, and Si (i=1, 2, 3...) can represent the surface of the lens in contact with air along the optical axis, or it can represent the cemented surface of two lenses.

[0071] Example 1

[0072] refer to Figure 1 and Figure 2 The optical system in this application includes, sequentially from the object side to the image side along the optical axis, a lens group 10 and an imaging lens 20. The optical system also includes an imaging surface IMG disposed on the image side of the imaging lens 20. Figure 2 As shown, in this embodiment, the lens group 10 includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a ninth lens E9, a tenth lens E10, an eleventh lens E11, a twelfth lens E12, a thirteenth lens E13, and a fourteenth lens E14 arranged sequentially from the object side to the image side along the optical axis; wherein, the first lens E1 and the second lens E2 are cemented together, the third lens E3 and the fourth lens E4 are cemented together, the seventh lens E7 and the eighth lens E8 are cemented together, the ninth lens E9 and the tenth lens E10 are cemented together, and the eleventh lens E11 and the twelfth lens E12 are cemented together.

[0073] Example 1 includes 14 lenses, and the effective focal length of the optical system is the same as the effective focal length when adapted to an imaging lens with a focal length of 22.48mm.

[0074] In this embodiment, the first lens E1 has positive optical power, and its object-side surface S1 and image-side surface S2 are convex. The second lens E2 has negative optical power, and its object-side surface S2 is concave, while its image-side surface S3 is convex. The third lens E3 has positive optical power, and its object-side surface S4 and image-side surface S5 are convex. The fourth lens E4 has negative optical power, and its object-side surface S5 is concave. The fourth lens E4 has a concave image-side surface S6; the fifth lens E5 has positive optical power, and its object-side surface S7 and image-side surface S8 are convex; the sixth lens E6 has positive optical power, and its object-side surface S9 and image-side surface S10 are convex; the seventh lens E7 has positive optical power, and its object-side surface S11 and image-side surface S12 are convex; the eighth lens E8 has negative optical power. The object-side surface S12 of the eighth lens E8 is concave, and the image-side surface S13 of the eighth lens E8 is concave; the ninth lens E9 has positive optical power, the object-side surface S14 of the ninth lens E9 is concave, and the image-side surface S15 of the ninth lens E9 is convex; the tenth lens E10 has negative optical power, the object-side surface S15 of the tenth lens E10 is concave, and the image-side surface S16 of the tenth lens E10 is convex; the eleventh lens E11 has negative optical power, the object-side surface S17 of the eleventh lens E11 is concave, and the image-side surface S16 of the eleventh lens E11 is convex. The image-side surface S18 of lens 1 is concave; the twelfth lens E12 has positive optical power, the object-side surface S18 of lens E12 is convex, and the image-side surface S19 of lens E12 is convex; the thirteenth lens E13 has positive optical power, the object-side surface S20 of lens E13 is concave, and the image-side surface S21 of lens E13 is convex; the fourteenth lens E14 has positive optical power, the object-side surface S22 of lens E14 is convex, and the image-side surface S23 of lens E14 is convex.

[0075] In addition, Table 1 shows the basic optical parameters of the lens group 10 of the optical system in Embodiment 1, wherein the units of radius of curvature and thickness / distance are millimeters (mm).

[0076] Table 1

[0077]

[0078] In this embodiment, the object-side surface S9 and image-side surface S10 of the sixth lens E6 are both aspherical surfaces, and the surface shape of each aspherical surface can be defined using, but is not limited to, the following aspherical surface formula:

[0079] ;

[0080] in,x is the distance vector from the vertex of the aspherical surface at a height of h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface.

[0081] Table 2 below shows the higher-order coefficients A4, A6, and A8 that can be used for the aspherical surfaces S9 and S10 in Example 1.

[0082] Table 2

[0083]

[0084] Figure 3 , Figure 4 and Figure 5 The astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical system in this embodiment are shown respectively. Figures 3 to 5 It can be seen that the optical system in this embodiment has good imaging quality.

[0085] Example 2

[0086] refer to Figure 1 and Figure 6 The optical system in this application includes, sequentially from the object side to the image side along the optical axis, a lens group 10 and an imaging lens 20. The optical system also includes an imaging surface IMG disposed on the image side of the imaging lens 20. Figure 6 As shown, in this embodiment, the lens group 10 includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a ninth lens E9, a tenth lens E10, an eleventh lens E11, a twelfth lens E12, a thirteenth lens E13, and a fourteenth lens E14 arranged sequentially from the object side to the image side along the optical axis; wherein, the first lens E1 and the second lens E2 are cemented together, the third lens E3 and the fourth lens E4 are cemented together, the seventh lens E7 and the eighth lens E8 are cemented together, the ninth lens E9 and the tenth lens E10 are cemented together, and the eleventh lens E11 and the twelfth lens E12 are cemented together.

[0087] Example 2 includes 14 lenses, and the effective focal length of the optical system is the same as the effective focal length when adapted to an imaging lens with a focal length of 22.48mm.

[0088] In this embodiment, the first lens E1 has positive optical power, and its object-side surface S1 and image-side surface S2 are convex. The second lens E2 has negative optical power, and its object-side surface S2 and image-side surface S3 are concave. The third lens E3 has positive optical power, and its object-side surface S4 and image-side surface S5 are convex. The fourth lens E4 has negative optical power, and its object-side surface S5 is concave. The fourth lens E4 has a concave image-side surface S6; the fifth lens E5 has positive optical power, and its object-side surface S7 and image-side surface S8 are both convex; the sixth lens E6 has positive optical power, and its object-side surface S9 and image-side surface S10 are both convex; the seventh lens E7 has positive optical power, and its object-side surface S11 and image-side surface S12 are both convex; the eighth lens E8 has negative optical power... The object-side surface S12 of the eighth lens E8 is convex, and the image-side surface S13 of the eighth lens E8 is concave; the ninth lens E9 has positive optical power, the object-side surface S14 of the ninth lens E9 is concave, and the image-side surface S15 of the ninth lens E9 is convex; the tenth lens E10 has negative optical power, the object-side surface S15 of the tenth lens E10 is concave, and the image-side surface S16 of the tenth lens E10 is convex; the eleventh lens E11 has negative optical power, the object-side surface S17 of the eleventh lens E11 is concave, and the image-side surface S16 of the eleventh lens E11 is convex. The image-side surface S18 of lens 1 is concave; the twelfth lens E12 has positive optical power, the object-side surface S18 of lens E12 is convex, and the image-side surface S19 of lens E12 is convex; the thirteenth lens E13 has positive optical power, the object-side surface S20 of lens E13 is convex, and the image-side surface S21 of lens E13 is convex; the fourteenth lens E14 has positive optical power, the object-side surface S22 of lens E14 is convex, and the image-side surface S23 of lens E14 is convex.

[0089] In addition, Table 3 shows the basic optical parameters of the lens group 10 of the optical system in Embodiment 2, wherein the units of radius of curvature and thickness / distance are millimeters (mm).

[0090] Table 3

[0091]

[0092] Figure 7 , Figure 8 and Figure 9 The astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical system in this embodiment are shown respectively. Figures 7 to 9 It can be seen that the optical system in this embodiment has good imaging quality.

[0093] Example 3

[0094] refer to Figure 1 and Figure 10 The optical system in this application includes, sequentially from the object side to the image side along the optical axis, a lens group 10 and an imaging lens 20. The optical system also includes an imaging surface IMG disposed on the image side of the imaging lens 20. Figure 10 As shown, in this embodiment, the lens group 10 includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a ninth lens E9, a tenth lens E10, an eleventh lens E11, a twelfth lens E12, a thirteenth lens E13, and a fourteenth lens E14 arranged sequentially from the object side to the image side along the optical axis; wherein, the first lens E1 and the second lens E2 are cemented together, the third lens E3 and the fourth lens E4 are cemented together, the seventh lens E7 and the eighth lens E8 are cemented together, the ninth lens E9 and the tenth lens E10 are cemented together, and the eleventh lens E11 and the twelfth lens E12 are cemented together.

[0095] Example 3 includes 14 lenses, and the effective focal length of the optical system is the same as the effective focal length when adapted to an imaging lens with a focal length of 22.48mm.

[0096] In this embodiment, the first lens E1 has positive optical power, and its object-side surface S1 and image-side surface S2 are convex. The second lens E2 has negative optical power, and its object-side surface S2 is concave, while its image-side surface S3 is convex. The third lens E3 has positive optical power, and its object-side surface S4 and image-side surface S5 are convex. The fourth lens E4 has negative optical power, and its object-side surface S5 is concave. The fourth lens E4 has a concave image-side surface S6; the fifth lens E5 has positive optical power, with a concave object-side surface S7 and a convex image-side surface S8; the sixth lens E6 has positive optical power, with a convex object-side surface S9 and a concave image-side surface S10; the seventh lens E7 has positive optical power, with a convex object-side surface S11 and a convex image-side surface S12; the eighth lens E8 has negative optical power. The object-side surface S12 of the eighth lens E8 is concave, and the image-side surface S13 of the eighth lens E8 is concave; the ninth lens E9 has positive optical power, the object-side surface S14 of the ninth lens E9 is concave, and the image-side surface S15 of the ninth lens E9 is convex; the tenth lens E10 has negative optical power, the object-side surface S15 of the tenth lens E10 is concave, and the image-side surface S16 of the tenth lens E10 is convex; the eleventh lens E11 has negative optical power, the object-side surface S17 of the eleventh lens E11 is concave, and the image-side surface S16 of the eleventh lens E11 is convex. The image-side surface S18 of lens 1 is concave; the twelfth lens E12 has positive optical power, the object-side surface S18 of lens E12 is convex, and the image-side surface S19 of lens E12 is convex; the thirteenth lens E13 has positive optical power, the object-side surface S20 of lens E13 is convex, and the image-side surface S21 of lens E13 is convex; the fourteenth lens E14 has positive optical power, the object-side surface S22 of lens E14 is concave, and the image-side surface S23 of lens E14 is convex.

[0097] In addition, Table 4 shows the basic optical parameters of the lens group 10 of the optical system in Embodiment 3, wherein the units of radius of curvature and thickness / distance are millimeters (mm).

[0098] Table 4

[0099]

[0100] Figure 11 , Figure 12 and Figure 13 The astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical system in this embodiment are shown respectively. Figures 11 to 13 It can be seen that the optical system in this embodiment has good imaging quality.

[0101] Example 4

[0102] refer to Figure 1 and Figure 14 The optical system in this application includes, sequentially from the object side to the image side along the optical axis, a lens group 10 and an imaging lens 20. The optical system also includes an imaging surface IMG disposed on the image side of the imaging lens 20. Figure 14 As shown, in this embodiment, the lens group 10 includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a ninth lens E9, a tenth lens E10, an eleventh lens E11, a twelfth lens E12, a thirteenth lens E13, and a fourteenth lens E14 arranged sequentially from the object side to the image side along the optical axis; wherein, the first lens E1 and the second lens E2 are cemented together, the third lens E3 and the fourth lens E4 are cemented together, the seventh lens E7 and the eighth lens E8 are cemented together, the ninth lens E9 and the tenth lens E10 are cemented together, and the eleventh lens E11 and the twelfth lens E12 are cemented together.

[0103] Example 4 includes 14 lenses, and the effective focal length of the optical system is the same as the effective focal length when adapted to an imaging lens with a focal length of 22.48mm.

[0104] In this embodiment, the first lens E1 has positive optical power, and its object-side surface S1 and image-side surface S2 are convex. The second lens E2 has negative optical power, and its object-side surface S2 is concave, while its image-side surface S3 is convex. The third lens E3 has positive optical power, and its object-side surface S4 and image-side surface S5 are convex. The fourth lens E4 has negative optical power, and its object-side surface S5 is concave. The fourth lens E4 has a concave image-side surface S6; the fifth lens E5 has positive optical power, with a convex object-side surface S7 and a concave image-side surface S8; the sixth lens E6 has negative optical power, with a convex object-side surface S9 and a concave image-side surface S10; the seventh lens E7 has positive optical power, with a concave object-side surface S11 and a convex image-side surface S12; the eighth lens E8 has negative optical power... The object-side surface S12 of the eighth lens E8 is concave, and the image-side surface S13 of the eighth lens E8 is convex; the ninth lens E9 has positive optical power, and its object-side surface S14 and image-side surface S15 are convex; the tenth lens E10 has positive optical power, and its object-side surface S15 is concave, and its image-side surface S16 is convex; the eleventh lens E11 has negative optical power, and its object-side surface S17 is convex. The image-side surface S18 of lens 1 is concave; the twelfth lens E12 has positive optical power, the object-side surface S18 of lens E12 is convex, and the image-side surface S19 of lens E12 is convex; the thirteenth lens E13 has negative optical power, the object-side surface S20 of lens E13 is concave, and the image-side surface S21 of lens E13 is concave; the fourteenth lens E14 has positive optical power, the object-side surface S22 of lens E14 is convex, and the image-side surface S23 of lens E14 is concave.

[0105] In addition, Table 5 shows the basic optical parameters of the lens group 10 of the optical system in Embodiment 4, wherein the units of radius of curvature and thickness / distance are millimeters (mm).

[0106] Table 5

[0107]

[0108] Figure 15 , Figure 16 and Figure 17 The astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical system in this embodiment are shown respectively. Figures 15 to 17 It can be seen that the optical system in this embodiment has good imaging quality.

[0109] Example 5

[0110] refer to Figure 1 and Figure 18 The optical system in this application includes, sequentially from the object side to the image side along the optical axis, a lens group 10 and an imaging lens 20. The optical system also includes an imaging surface IMG disposed on the image side of the imaging lens 20. Figure 18 As shown, in this embodiment, the lens group 10 includes a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a ninth lens E9, a tenth lens E10, an eleventh lens E11, a twelfth lens E12, a thirteenth lens E13, and a fourteenth lens E14 arranged sequentially from the object side to the image side along the optical axis; wherein, the first lens E1 and the second lens E2 are cemented together, the third lens E3 and the fourth lens E4 are cemented together, the seventh lens E7 and the eighth lens E8 are cemented together, the ninth lens E9 and the tenth lens E10 are cemented together, and the eleventh lens E11 and the twelfth lens E12 are cemented together.

[0111] Example 5 includes 14 lenses, and the effective focal length of the optical system is the same as the effective focal length when adapted to an imaging lens with a focal length of 22.48mm.

[0112] In this embodiment, the first lens E1 has positive optical power, and its object-side surface S1 and image-side surface S2 are convex. The second lens E2 has negative optical power, and its object-side surface S2 and image-side surface S3 are concave. The third lens E3 has positive optical power, and its object-side surface S4 and image-side surface S5 are convex. The fourth lens E4 has negative optical power, and its object-side surface S5 is concave. The fourth lens E4 has a concave image-side surface S6; the fifth lens E5 has positive optical power, and its object-side surface S7 and image-side surface S8 are both convex; the sixth lens E6 has positive optical power, and its object-side surface S9 and image-side surface S10 are both convex; the seventh lens E7 has positive optical power, and its object-side surface S11 and image-side surface S12 are both convex; the eighth lens E8 has negative optical power... The object-side surface S12 of the eighth lens E8 is convex, and the image-side surface S13 of the eighth lens E8 is concave; the ninth lens E9 has positive optical power, the object-side surface S14 of the ninth lens E9 is concave, and the image-side surface S15 of the ninth lens E9 is convex; the tenth lens E10 has negative optical power, the object-side surface S15 of the tenth lens E10 is concave, and the image-side surface S16 of the tenth lens E10 is convex; the eleventh lens E11 has negative optical power, the object-side surface S17 of the eleventh lens E11 is concave, and the image-side surface S16 of the eleventh lens E11 is convex. The image-side surface S18 of lens 1 is concave; the twelfth lens E12 has positive optical power, the object-side surface S18 of lens E12 is convex, and the image-side surface S19 of lens E12 is convex; the thirteenth lens E13 has positive optical power, the object-side surface S20 of lens E13 is convex, and the image-side surface S21 of lens E13 is convex; the fourteenth lens E14 has positive optical power, the object-side surface S22 of lens E14 is convex, and the image-side surface S23 of lens E14 is convex.

[0113] In addition, Table 6 shows the basic optical parameters of the lens group 10 of the optical system in Embodiment 5, wherein the units of radius of curvature and thickness / distance are millimeters (mm).

[0114] Table 6

[0115]

[0116] Figure 19 , Figure 20 and Figure 21 The astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical system in this embodiment are shown respectively. Figures 19 to 21 It can be seen that the optical system in this embodiment has good imaging quality.

[0117] Furthermore, the total effective focal length f of the optical system in Embodiments 1 to 5, the focal lengths f1~f14 of the first lens E1 to the fourteenth lens E14, the combined focal length F12 of the first lens E1 and the second lens E2, the combined focal length F34 of the third lens E3 and the fourth lens E4, the combined focal length F56 of the fifth lens E5 and the sixth lens E6, the combined focal length F78 of the seventh lens E7 and the eighth lens E8, the combined focal length F910 of the ninth lens E9 and the tenth lens E10, the combined focal length F1112 of the eleventh lens E11 and the twelfth lens E12, the combined focal length F1314 of the thirteenth lens E13 and the fourteenth lens E14, the distance TD on the optical axis between the object side surface S1 of the first lens E1 and the image side surface S23 of the fourteenth lens E14, and the sum of the center thicknesses ∑CT of all lenses in the first lens E1 to the fourteenth lens E14 are shown in Table 7 below.

[0118] Table 7

[0119]

[0120] The conditions satisfied by the optical systems of Examples 1 to 5 are shown in Table 8.

[0121] Table 8

[0122]

[0123] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0124] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An optical system comprising a lens group, characterized in that, The lens group, along the optical axis from the object side to the image side, includes the following in sequence: A first lens with positive optical power, wherein the object side of the first lens is convex and the image side of the first lens is convex. A second lens with negative optical power, wherein the object side of the second lens is concave; A third lens with positive optical power, wherein the object-side surface of the third lens is convex and the image-side surface of the third lens is convex; A fourth lens with negative optical power, wherein the object side of the fourth lens is concave and the image side of the fourth lens is concave. A fifth lens with positive optical power; A sixth lens having positive or negative optical power, wherein the object-side surface of the sixth lens is convex and the image-side surface of the sixth lens is concave. A seventh lens with positive optical power; An eighth lens with negative optical power; A ninth lens having positive optical power, wherein the image-side surface of the ninth lens is convex; A tenth lens having positive or negative optical power, wherein the object-side surface of the tenth lens is concave and the image-side surface of the tenth lens is convex. An eleventh lens with negative optical power, wherein the image-side surface of the eleventh lens is concave; A twelfth lens with positive optical power, wherein the object-side surface of the twelfth lens is convex and the image-side surface of the twelfth lens is convex; A thirteenth lens with positive or negative optical power; The fourteenth lens with positive optical power; Wherein, the first lens and the second lens are cemented together, the third lens and the fourth lens are cemented together, the ninth lens and the tenth lens are cemented together, and the eleventh lens and the twelfth lens are cemented together; and the optical system satisfies: 0.36≤F12 / |F34|≤1.65; 0.09≤F1112 / |F910|≤1.57; 3.35≤TD / (T23+T45)<3.90; Wherein, F12 is the combined focal length of the first lens and the second lens, F34 is the combined focal length of the third lens and the fourth lens, F1112 is the combined focal length of the eleventh lens and the twelfth lens, F910 is the combined focal length of the ninth lens and the tenth lens, TD is the distance on the optical axis from the object side of the first lens to the image side of the fourteenth lens, T23 is the air gap on the optical axis between the second lens and the third lens, and T45 is the air gap on the optical axis between the fourth lens and the fifth lens.

2. The optical system according to claim 1, characterized in that, The seventh lens and the eighth lens are cemented together, and the optical system satisfies: -7.20 < F78 / (CT7+CT8) < -2.65; where F78 is the combined focal length of the seventh lens and the eighth lens, CT7 is the center thickness of the seventh lens, and CT8 is the center thickness of the eighth lens.

3. The optical system according to claim 1, characterized in that, The optical system satisfies: 3.70 < f1 / CT1 < 5.45; where f1 is the effective focal length of the first lens and CT1 is the center thickness of the first lens.

4. The optical system according to claim 1, characterized in that, The optical system satisfies: 0.55 < (CT9 + CT10) / (CT11 + CT12) < 1.95; where CT9 is the center thickness of the ninth lens, CT10 is the center thickness of the tenth lens, CT11 is the center thickness of the eleventh lens, and CT12 is the center thickness of the twelfth lens.

5. The optical system according to claim 1, characterized in that, The optical system satisfies: -2.40 < R24 / f12 ≤ -1.45; where R24 is the radius of curvature of the image side surface of the twelfth lens, and f12 is the effective focal length of the twelfth lens.

6. The optical system according to claim 1, characterized in that, The optical system satisfies: 0.40 < F1112 / (f13+f14) < 3.75; where F1112 is the combined focal length of the eleventh lens and the twelfth lens, f13 is the effective focal length of the thirteenth lens, and f14 is the effective focal length of the fourteenth lens.

7. The optical system according to claim 1, characterized in that, The optical system satisfies: 2.40 < R5 / (CT3+CT4) < 5.50; where R5 is the radius of curvature of the object side of the third lens, CT3 is the center thickness of the third lens, and CT4 is the center thickness of the fourth lens.

8. The optical system according to claim 1, characterized in that, The optical system satisfies: 0.25 < F1314 / F56 < 1.35; where F1314 is the combined focal length of the thirteenth and fourteenth lenses, and F56 is the combined focal length of the fifth and sixth lenses.

9. The optical system according to claim 1, characterized in that, The optical system satisfies: 1.05 < ∑CT / |F1314| ≤ 2.20; where ∑CT is the sum of the center thicknesses of all lenses from the first lens to the fourteenth lens, and F1314 is the combined focal length of the thirteenth lens and the fourteenth lens.

10. The optical system according to claim 1, characterized in that, The optical system satisfies: 1.65 < (N3 + N4) / N5 < 1.95; where N3 is the refractive index of the third lens, N4 is the refractive index of the fourth lens, and N5 is the refractive index of the fifth lens.

11. The optical system according to claim 1, characterized in that, The optical system satisfies: 0.95 < (V11 + V12) / (V9 + V10) < 1.60; where V11 is the Abbe number of the eleventh lens, V12 is the Abbe number of the twelfth lens, V9 is the Abbe number of the ninth lens, and V10 is the Abbe number of the tenth lens.

12. The optical system according to claim 1, characterized in that, The optical system satisfies: -3.85 < (f2 + f4) / f3 < -1.60; where f2 is the effective focal length of the second lens, f4 is the effective focal length of the fourth lens, and f3 is the effective focal length of the third lens.

13. The optical system according to claim 1, characterized in that, The optical system satisfies: 0.96≤|(f7 / f8)×(f9 / f10)|≤1.95; where f7 is the effective focal length of the seventh lens, f8 is the effective focal length of the eighth lens, f9 is the effective focal length of the ninth lens, and f10 is the effective focal length of the tenth lens.

14. The optical system according to claim 1, characterized in that, The optical system satisfies: -1.85 < f11 / R22 < -0.50; where f11 is the effective focal length of the eleventh lens and R22 is the radius of curvature of the image side surface of the eleventh lens.

15. The optical system according to claim 1, characterized in that, The optical system satisfies: -11.65 < f / (CT5+CT6) < -5.70; where f is the effective focal length of the optical system, CT5 is the center thickness of the fifth lens, and CT6 is the center thickness of the sixth lens.

16. The optical system according to claim 1, characterized in that, The optical system also includes an imaging lens and an imaging surface located on the image side of the fourteenth lens. The outgoing light beam from the lens group enters the imaging lens to form an image on the imaging surface using the imaging lens.

Images