Imaging lens and camera device

Abstract

The present invention relates to the technical field of wide-angle optical systems, and specifically to an imaging lens and a camera device, comprising a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having positive refractive power, wherein the first lens group comprises a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, and the fourth lens and the fifth lens are bonded together to form a bonded lens B01. The device is suitable for use in photographic lenses of camera devices such as still cameras and video cameras. Regarding the optical system for large-aperture wide-angle lenses, in particular, by appropriately configuring glass materials, various aberrations such as spherical aberration, axial chromatic aberration, magnification chromatic aberration, and coma can be well corrected. Therefore, good image quality can be obtained across the entire image, and the device can be connected to a miniaturized camera body such as a single-lens reflex camera, thereby providing such a large-aperture optical system.

Description

Technical Field

[0001] The present invention relates to the technical field of wide-angle optical systems, and in particular to an imaging lens and a camera device. Background Art

[0002] In recent years, digital cameras and digital video cameras with interchangeable lenses have become widely used. In traditional wide-angle optical systems, a back focus distance of at least a certain distance must be maintained. Therefore, many optical systems use a positive lens group at the rear to ensure a longer back focus distance.

[0003] However, when a positive lens group is configured on the side closest to the optical system, the optical focal length of the focusing group will be enhanced to a certain extent, so it is easy to produce aberration changes and magnification effects caused by the shaking of the lens group during focusing. Therefore, it is particularly important to improve the existing imaging lenses and camera devices, design a new imaging lens and camera device to change the above-mentioned technical defects, and improve the practicality of the overall imaging lens and camera device. Summary of the Invention

[0004] The object of the present invention is to provide an imaging lens and a camera device to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An imaging lens and a camera device, comprising a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having positive refractive power, wherein the first lens group comprises a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, wherein the fourth lens and the fifth lens are bonded together to form a bonded lens B01, the second lens group comprises a sixth lens, a seventh lens, an eighth lens, and a ninth lens, wherein the seventh lens, the eighth lens, and the ninth lens are bonded together to form a bonded lens B02, and the third lens group comprises a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, and a fourteenth lens, wherein the tenth lens, the eleventh lens, and the twelfth lens are bonded together to form a triplet lens B03;

[0007] When the third lens group focuses from an infinitely distant object to a close object, the second lens group and the third lens group satisfy the following conditional expressions:

[0008] 1.88 <nd1 L1;

[0009] 60.0 <vd1max-vd1 L1;

[0010] nd1 L1: refractive index of the first lens element of the meniscus lens having negative refractive power with its convex surface facing the object side of the first lens group;

[0011] vd1max: the maximum value of the Abbe number of the lenses other than the first lens having negative refractive power of the first lens group;

[0012] vd1 L1: the upper edge number of the first lens element of the meniscus lens with negative refractive power and a convex surface on the object side of the first lens group;

[0013] nd1 p<1.7;

[0014] 23vda<1.75;

[0015] nd1 p: average refractive index of lenses with positive refractive power of the first lens group;

[0016] 23vda: average refractive index of lenses with positive refractive power of the second and third lens groups;

[0017] The non-curved surface shape meets the following conditions:

[0018] 1.15≤L2R / SG2≤1.5

[0019] Wherein, L2R: the paraxial radius of curvature of the surface of the second lens group closest to the image side;

[0020] SG2: The height of the surface of the second lens group closest to the image side, starting from the center of the optical axis to the effective aperture is the curvature radius L2R of this surface.

[0021] As a preferred solution of the present invention, the first lens is a meniscus lens with negative optical power, with the convex surface facing the object; the second lens is a meniscus lens with negative optical power, with the convex surface facing the object; the third lens is a meniscus lens with positive optical power, with the convex surface facing the object; the fourth lens is a biconcave lens with negative optical power; and the fifth lens is a meniscus lens with positive optical power, with the convex surface facing the object.

[0022] As a preferred solution of the present invention, the sixth lens is a biconvex lens with positive focal power; the seventh lens is a biconvex lens with positive focal power; the eighth lens is a biconcave lens with negative focal power; and the ninth lens is a meniscus lens with positive focal power, with the convex surface facing the object side.

[0023] As a preferred embodiment of the present invention, the tenth lens is a meniscus lens with positive focal power, with the convex surface facing the image side; the eleventh lens is a biconcave lens with negative focal power; the twelfth lens is a biconvex lens with positive focal power; the thirteenth lens is a biconvex lens with positive focal power; and the fourteenth lens is a meniscus lens with negative focal power.

[0024] As a preferred solution of the present invention, the second lens group and the third lens group are separated by an air gap on the longest optical axis of the second lens group, and the aperture is placed between the second lens group and the third lens group, wherein the surface closest to the object is concave relative to the object, and satisfies the following formula:

[0025] -1.2 <f / R2Bf<-0.5;

[0026] f: the focal length of the entire optical system when focusing on an object at infinity;

[0027] R2Bf: The radius of curvature of the object-side optical surface in the third lens group.

[0028] As a preferred embodiment of the present invention, the shapes of the cemented lens B02 are convex-concave-convex, and the shapes of the triplet lens B03 are convex-concave-convex. The Abbe numbers of the tenth lens, the eleventh lens, and the twelfth lens are arranged in a "high-low-high" arrangement, respectively, to eliminate coma and astigmatism, and effectively correct the chromatic aberration of magnification of the third lens group during focusing, thus satisfying the following conditional expression:

[0029] 0.30 <vd11 / vd10<0.45;

[0030] 0.30 <vd11 / vd12<0.45;

[0031] Among them: the Abbe number of the tenth lens is vd10;

[0032] The Abbe number of the eleventh lens is vd11;

[0033] The Abbe number of the twelfth lens is vd12.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The present invention provides an imaging lens and an imaging device designed to be suitable for use in photographic lenses for imaging devices such as still cameras and video cameras. Regarding the optical system used in a large-aperture wide-angle lens, the present invention, through the appropriate arrangement of glass materials, can effectively correct various aberrations, such as spherical aberration, axial chromatic aberration, lateral chromatic aberration, and coma, thereby achieving excellent image quality across the entire image. Furthermore, the present invention provides a large-aperture optical system that can be integrated into a conventional camera body, such as a single-lens reflex camera, in a compact form.

[0036] The relative illumination of the optical lens of the present invention is about 10-15% higher than that of an ordinary standard lens. The relative illumination of an ordinary standard lens is about 25-30%. The relative illumination of this optical lens is as high as 40%, which is particularly suitable for application scenarios where shading correction cannot be performed, such as dynamic image recording.

[0037] The optical lens of the present invention is a wide-angle lens design with a field of view of 83.5° to 85.3°. The change in viewing angle from infinity to the shortest photographic distance is very small.

[0038] The optical lens of the present invention has very low distortion, with optical distortion less than 2.4%;

[0039] In addition, the present invention is designed with twelve spherical glass lenses and two molded glass lenses. The use of aspherical surfaces can effectively improve central chromatic aberration and suppress distortion, and the large-aperture aspherical lens has extremely high processability. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic diagram of the overall explosion structure of the present invention;

[0041] Figure 2 The experimental data curve of the present invention Figure 1 ;

[0042] Figure 3 The experimental data curve of the present invention Figure 2 ;

[0043] Figure 4 The experimental data curve of the present invention Figure 3 .

[0044] In the figure: 1-first lens group, 101-first lens, 102-second lens, 103-third lens, 104-fourth lens, 105-fifth lens, 2-second lens group, 201-sixth lens, 202-seventh lens, 203-eighth lens, 204-ninth lens, 3-third lens group, 301-tenth lens, 302-eleventh lens, 303-twelfth lens, 304-thirteenth lens, 305-fourteenth lens. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0046] To facilitate understanding of the present invention, the present invention will be described more comprehensively below with reference to relevant references, and several embodiments of the present invention are given. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0047] It should be noted that when an element is referred to as being "fixed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this article are for illustrative purposes only.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The terms used in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0049] See also Figures 1-4 , the present invention provides a technical solution:

[0050] Example:

[0051] An imaging lens and a camera device include a first lens group 1 having negative refractive power, a second lens group 2 having positive refractive power, and a third lens group 3 having positive refractive power. The first lens group 1 includes a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, and a fifth lens 105. The fourth lens 104 and the fifth lens 105 are bonded together to form a bonded lens B01. The second lens group 2 includes a sixth lens 201, a seventh lens 202, an eighth lens 203, and a ninth lens 204. The seventh lens 202, the eighth lens 203, and the ninth lens 204 are bonded together to form a bonded lens B02. The third lens group 3 includes a tenth lens 301, an eleventh lens 302, a twelfth lens 303, a thirteenth lens 304, and a fourteenth lens 305. The tenth lens 301, the eleventh lens 302, and the twelfth lens 303 are bonded together to form a triplet lens B03.

[0052] In this embodiment, the implementation scenario is specifically as follows: the disclosed optical system has a large diameter by arranging a lens having positive refractive power and a lens having negative refractive power in an appropriate positional relationship in a lens group on the object side, which achieves correction of sagittal coma aberration while suppressing an increase in lens diameter;

[0053] Therefore, the present invention relates to an optical system used in a large-diameter wide-angle lens for use in a photographic lens suitable for an imaging device such as an interchangeable-lens digital camera or a video camera. In particular, by appropriately arranging glass materials, various aberrations such as spherical aberration, longitudinal chromatic aberration, lateral chromatic aberration, and coma can be well corrected, thereby achieving good image quality across the entire screen. Furthermore, the optical system is reduced in size to a degree that allows attachment to a typical camera body such as a single-lens reflex camera.

[0054] The following conditions must be met during the implementation of this plan:

[0055] 1.88 <nd1 L1;

[0056] 60.0 <vd1max-vd1 L1;

[0057] nd1 L1: refractive index of the first lens element 101 having a negative refractive power of the meniscus lens with its convex surface facing the object side of the first lens group 1;

[0058] vd1max: the maximum value of the Abbe number of the lenses other than the first lens 101 having negative refractive power of the first lens group 1;

[0059] vd1 L1: the upper edge number of the first lens element 101 of the meniscus lens having a negative refractive power and a convex surface on the object side of the first lens group 1;

[0060] nd1 p<1.7;

[0061] 23vda<1.75;

[0062] nd1 p: average refractive index of lenses with positive refractive power in the first lens group 1;

[0063] 23vda: average refractive index of lenses with positive refractive power of the second lens group 2 and the third lens group 3;

[0064] The non-curved surface shape meets the following conditions:

[0065] 1.15≤L2R / SG2≤1.5

[0066] Wherein, L2R: paraxial radius of curvature of the surface of the second lens group 2 closest to the image side;

[0067] SG2: The height of the surface of the second lens group 2 closest to the image side, starting from the center of the optical axis to the effective aperture equal to the curvature radius L2R of this surface;

[0068] The second lens group 2 and the third lens group 3 are separated by an air gap on the longest optical axis of the second lens group 2, and the aperture stop is placed between the second lens group 2 and the third lens group 3, wherein the surface closest to the object is concave relative to the object, and satisfies the following formula:

[0069] -1.2 <f / R2Bf<-0.5;

[0070] f: the focal length of the entire optical system when focusing on an object at infinity;

[0071] R2Bf: radius of curvature of the object-side optical surface of the third lens group 3;

[0072] The shapes of the cemented lens B02 are convex-concave-convex, and the shapes of the triplet lens B03 are convex-concave-convex. The Abbe numbers of the tenth lens 301, the eleventh lens 302, and the twelfth lens 303 are arranged in a "high-low-high" arrangement, thereby eliminating coma and astigmatism and effectively correcting chromatic aberration of magnification in the third lens group 3 during focusing. The following conditional expression is satisfied:

[0073] 0.30 <vd11 / vd10<0.45;

[0074] 0.30 <vd11 / vd12<0.45;

[0075] Wherein: the Abbe number of the tenth lens 301 is vd10;

[0076] The Abbe number of the eleventh lens 302 is vd11;

[0077] The Abbe number of the twelfth lens 303 is vd12.

[0078] The specific experimental data table is as follows:

[0079] example

[0080]

[0081]

[0082]

[0083] Aspheric surface data

[0084]

[0085] surface K A2 A4 A6 A8 A10 3 0 0 1.49582E-05 -5.71251E-08 1.40386E-10 -1.72291E-13 4 0 0 3.75060E-05 -9.86248E-08 2.37140E-10 -5.00379E-13 23 0 0 4.76984E-05 -1.45509E-08 -5.88738E-11 9.54581E-14 24 0 0 4.23764E-05 -4.71108E-09 -4.85759E-11 2.69854E-14

[0086] Various data

[0087] focal distance Inf 24.56 Fno 1.86 2.0 Full frame angle 83.3 82.7 Like Gao Y 21.63 21.63 Full length of lens 144.125 144.125

[0088] Variable interval data

[0089]

[0090]

[0091] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An imaging lens and a camera device, comprising a first lens group (1) having negative refractive power, a second lens group (2) having positive refractive power, and a third lens group (3) having positive refractive power, characterized in that: The first lens group (1) includes a first lens (101), a second lens (102), a third lens (103), a fourth lens (104) and a fifth lens (105), and the fourth lens (104) and the fifth lens (105) are bonded together to form a bonded lens B01. The second lens group (2) includes a sixth lens (201), a seventh lens (202), an eighth lens (203) and a ninth lens (204), and the seventh lens (202), the eighth lens (203) and the ninth lens (204) are bonded together to form a bonded lens B02. The third lens group (3) includes a tenth lens (301), an eleventh lens (302), a twelfth lens (303), a thirteenth lens (304) and a fourteenth lens (305), and the tenth lens (301), the eleventh lens (302) and the twelfth lens (303) are bonded together to form a triplet lens B03. When the third lens group (3) focuses from an infinitely distant object to a close object, the second lens group (2) and the third lens group satisfy the following conditional formula: 1.88 <nd1 L1; 60.0 <vd1max-vd1 L1; nd1 L1: refractive index of the first lens element (101) of the meniscus lens having a negative refractive power with its convex surface facing the object side of the first lens group (1); vd1max: the maximum value of the Abbe number of the lenses other than the first lens (101) having the negative refractive power of the first lens group (1); vd1 L1: the upper edge number of the first lens element (101) of the meniscus lens having a negative refractive power facing the convex surface on the object side of the first lens group (1); nd1 p<1.7; 23vda<1.75; nd1 p: average refractive index of the lenses having positive refractive power of the first lens group (1); 23vda: average refractive index of lenses having positive refractive power of the second lens group (2) and the third lens group (3); The non-curved surface shape meets the following conditions: 1.15≤L2R / SG2≤1.5 Wherein, L2R: the paraxial curvature radius of the surface of the second lens group (2) closest to the image side; SG2: The height of the surface of the second lens group (2) closest to the image side, starting from the center of the optical axis to the effective aperture when the curvature radius L2R of this surface is reached.

2. The imaging lens and camera device according to claim 1, wherein: The first lens (101) is a meniscus lens with negative optical power, with its convex surface facing the object; the second lens (102) is a meniscus lens with negative optical power, with its convex surface facing the object; the third lens (103) is a meniscus lens with positive optical power, with its convex surface facing the object; the fourth lens (104) is a biconcave lens with negative optical power; and the fifth lens (105) is a meniscus lens with positive optical power, with its convex surface facing the object.

3. The imaging lens and camera device according to claim 1, wherein: The sixth lens (201) is a biconvex lens with positive focal power; the seventh lens (202) is a biconvex lens with positive focal power; the eighth lens (203) is a biconcave lens with negative focal power; and the ninth lens (204) is a meniscus lens with positive focal power, with the convex surface facing the object side.

4. The imaging lens and camera device according to claim 1, wherein: The tenth lens (301) is a meniscus lens with positive focal power, with the convex surface facing the image side; the eleventh lens (302) is a biconcave lens with negative focal power; the twelfth lens (303) is a biconvex lens with positive focal power; the thirteenth lens (304) is a biconvex lens with positive focal power; and the fourteenth lens (305) is a meniscus lens with negative focal power.

5. The imaging lens and camera device according to claim 1, wherein: The second lens group (2) and the third lens group (3) are separated by an air gap on the longest optical axis of the second lens group (2), and the aperture is placed between the second lens group (2) and the third lens group (3), wherein the surface closest to the object is concave relative to the object, and satisfies the following formula: -1.2 <f / R2Bf<-0.5; f: the focal length of the entire optical system when focusing on an object at infinity; R2Bf: The radius of curvature of the object-side optical surface in the third lens group (3).

6. The imaging lens and camera device according to claim 1, wherein: The shapes of the cemented lens B02 are convex-concave-convex, and the shapes of the triplet lens B03 are convex-concave-convex, wherein the Abbe numbers of the tenth lens (301), the eleventh lens (302) and the twelfth lens (303) are "10-11-12" in sequence and are arranged in a "high-low-high" arrangement. Due to the elimination of coma and astigmatism, and the ability to effectively correct the magnification chromatic aberration of the third lens group (3) during the focusing process, the following conditional formula is satisfied: 0.30 <vd11 / vd10<0.45; 0.30 <vd11 / vd12<0.45; Wherein: the Abbe number of the tenth lens (301) is vd10; The Abbe number of the eleventh lens (302) is vd11; The Abbe number of the twelfth lens (303) is vd12.

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