Macro lens

Abstract

The macro lens comprises a first lens group, a second lens group and a third lens group which are arranged from an object plane to an image plane along an optical axis, the first lens group has negative focal power and comprises a first lens and a second lens; the second lens group has positive focal power and comprises a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens; the third lens, the fourth lens, the sixth lens, the seventh lens and the ninth lens are lenses with positive focal power, and the fifth lens and the eighth lens are lenses with negative focal power; the third lens group has negative focal power and comprises a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens and a fourteenth lens; in the focusing process from infinity to close distance, the second lens group moves towards the object side along the optical axis, and the first lens group and the third lens group are fixed. A three-component structure is adopted, and when the object distance changes, the second lens group is adjusted to move along the optical axis to achieve focusing of different object distances, so that clear imaging of the lens is realized.

Description

Technical Field

[0001] The embodiments of the present utility model relate to the technical field of optical devices, and particularly to a macro lens. Background Art

[0002] With the diversification of people's needs for cultural life, photography has become one of the popular entertainment items among the public. The lenses used for photography are also adapting to various usage scenarios to achieve different functions. A macro lens is a special lens used for macro photography, mainly used to photograph very fine objects, and can photograph both distant objects and close objects to achieve a close-up effect.

[0003] Most of the existing macro lenses have a focal length of 100mm or 75mm, and the magnification ratio is between equal magnification and 1.5 times. Moreover, the imaging aberration is obvious and the resolution is low. Summary of the Utility Model

[0004] The present utility model provides a macro lens, which realizes a macro lens with a focal length of about 60mm and can achieve good imaging for object distances from infinity to 2 times magnification by reasonably setting the composition mode of the lens, the composition mode of different lens groups, and the focusing movement mode.

[0005] The embodiments of the present utility model provide a macro lens, which includes a first lens group, a second lens group, and a third lens group arranged in sequence along the optical axis from the object plane to the image plane;

[0006] The first lens group is a negative optical power lens group and the first lens group includes a first lens and a second lens;

[0007] The second lens group is a positive optical power lens group and the second lens group includes a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens; the third lens, the fourth lens, the sixth lens, the seventh lens, and the ninth lens are positive optical power lenses, and the fifth lens and the eighth lens are negative optical power lenses;

[0008] The third lens group is a negative optical power lens group and the third lens group includes a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, and a fourteenth lens;

[0009] During the process of focusing from infinity to close range, the second lens group moves along the optical axis towards the object side, and the first lens group and the third lens group are fixed.

[0010] Optionally, in the infinity state, the focal length of the macro lens is F, and the focal length of the second lens group is F 2 ;

[0011] Among them, 1.68 < F / F2 <1.82。

[0012] Optionally, the movement amount of the second lens group during the focusing process from infinity to a close distance is ZOL, and the focal length of the macro lens in the infinity state is F;

[0013] Wherein, 0.54 < ZOL / F < 0.67.

[0014] Optionally, the overall optical power of the first lens group and the second lens group is Ф 12 , and the optical back focal length of the macro lens is L 后 ;

[0015] Wherein, 0.15 < 100*(Ф 12 / L 后 ) < 0.22.

[0016] Optionally, the eleventh lens and the twelfth lens are adhesively bonded;

[0017] The optical power of the eleventh lens is ФL 11 , the Abbe number of the eleventh lens is vd11, and the optical power of the twelfth lens is ФL 12 , and the Abbe number of the twelfth lens is vd12;

[0018] Wherein, 0.6 < 1000*(ФL 11 / vd11 + ФL 12 / vd12) < 0.85.

[0019] Optionally, both the sixth lens and the ninth lens are ultra-low dispersion lenses.

[0020] Optionally, the clear aperture of the first lens is D1, and the overall optical length of the macro lens is TTL;

[0021] Wherein, 0.19 < D1 / TTL < 0.23.

[0022] Optionally, the second lens, the tenth lens, and the thirteenth lens are all meniscus lenses.

[0023] Optionally, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, the thirteenth lens, and the fourteenth lens are all glass spherical lenses.

[0024] Optionally, the macro lens further includes a diaphragm and a filter;

[0025] The diaphragm is disposed in the optical path between the ninth lens and the tenth lens;

[0026] The filter is disposed in the optical path between the fourteenth lens and the image plane.

[0027] The macro lens provided by the embodiment of the present invention includes a first lens group with negative optical power, a second lens group with positive optical power, and a third lens group with negative optical power. During the process of focusing from infinity to a close distance, the first lens group and the third lens group remain stationary, and the second lens group moves to achieve high-performance imaging effects for object distances from infinity to a photographic magnification of 2 times. Further, the first lens group includes a first lens and a second lens, the second lens group includes a third lens with positive optical power, a fourth lens with positive optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, a seventh lens with positive optical power, an eighth lens with negative optical power, and a ninth lens with positive optical power, and the third lens group includes a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, and a fourteenth lens. By appropriately setting the composition of each lens group and the optical power of each lens in the focusing moving lens group, high-performance imaging effects can be achieved for object distances from infinity to a photographic magnification of 2 times in the macro lens.

[0028] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. Description of the Drawings

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0030] Figure 1 is a schematic structural diagram of a macro lens provided by Embodiment 1 of the present invention;

[0031] Figure 2 is a schematic diagram of the field curvature and distortion curve of a macro lens under an infinite object distance provided by Embodiment 1 of the present invention;

[0032] Figure 3 is a schematic diagram of the field curvature and distortion curve of a macro lens under a near object distance provided by Embodiment 1 of the present invention;

[0033] Figure 4 is a schematic diagram of the lateral chromatic aberration curve of a macro lens under an infinite object distance provided by Embodiment 1 of the present invention;

[0034] Figure 5 It is a schematic diagram of the lateral chromatic aberration curve of a macro lens under a near object distance provided in the first embodiment of the present utility model;

[0035] Figure 6 It is a schematic structural diagram of a macro lens provided in the second embodiment of the present utility model;

[0036] Figure 7 It is a schematic diagram of the field curvature and distortion curve of a macro lens under an infinite object distance provided in the second embodiment of the present utility model;

[0037] Figure 8 It is a schematic diagram of the field curvature and distortion curve of a macro lens under a near object distance provided in the second embodiment of the present utility model;

[0038] Figure 9 It is a schematic diagram of the lateral chromatic aberration curve of a macro lens under an infinite object distance provided in the second embodiment of the present utility model;

[0039] Figure 10 It is a schematic diagram of the lateral chromatic aberration curve of a macro lens under a near object distance provided in the second embodiment of the present utility model;

[0040] Figure 11 It is a schematic structural diagram of a macro lens provided in the third embodiment of the present utility model;

[0041] Figure 12 It is a schematic diagram of the field curvature and distortion curve of a macro lens under an infinite object distance provided in the third embodiment of the present utility model;

[0042] Figure 13 It is a schematic diagram of the field curvature and distortion curve of a macro lens under a near object distance provided in the third embodiment of the present utility model;

[0043] Figure 14 It is a schematic diagram of the lateral chromatic aberration curve of a macro lens under an infinite object distance provided in the third embodiment of the present utility model;

[0044] Figure 15 It is a schematic diagram of the lateral chromatic aberration curve of a macro lens under a near object distance provided in the third embodiment of the present utility model. Detailed implementation manners

[0045] To enable those skilled in the art to better understand the solution of the present utility model, the following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0046] Embodiment 1

[0047] Figure 1 is a schematic structural diagram of a macro lens provided in Embodiment 1 of the present utility model. As Figure 1 shown, the macro lens provided in Embodiment 1 of the present utility model includes a first lens group S1, a second lens group S2, and a third lens group S3 arranged in sequence along the optical axis from the object plane to the image plane; the first lens group S1 is a negative refractive power lens group and the first lens group S1 includes a first lens 101 and a second lens 102; the second lens group S2 is a positive refractive power lens group and the second lens group S2 includes a third lens 103, a fourth lens 104, a fifth lens 105, a sixth lens 106, a seventh lens 107, an eighth lens 108, and a ninth lens 109; the third lens 103, the fourth lens 104, the sixth lens 106, the seventh lens 107, and the ninth lens 109 are positive refractive power lenses, and the fifth lens 105 and the eighth lens 108 are negative refractive power lenses; the third lens group S3 is a negative refractive power lens group and the third lens group S3 includes a tenth lens 110, an eleventh lens 111, a twelfth lens 112, a thirteenth lens 113, and a fourteenth lens 114; during the process of focusing from infinity to a close distance, the second lens group S2 moves along the optical axis towards the object side, and the first lens group S1 and the third lens group S3 are fixed.

[0048] In the zoom lens provided in this embodiment, the fixed lens group S1, the focusing lens group S2, and the fixed lens group S3 can be arranged in a lens barrel ( Figure 1 not shown in the figure). The fixed lens groups S1 and S3 are fixed in position in the lens barrel, and the focusing lens group S2 can move along the optical axis in the lens barrel. By moving the focusing lens group S2, high-performance imaging effects can be achieved for the macro lens with object distances ranging from infinity to a 2-fold photographic magnification.

[0049] Furthermore, the optical power is equal to the difference between the converging degree of the image plane light beam and the converging degree of the object plane light beam, which characterizes the ability of the optical system to deflect light rays. The greater the absolute value of the optical power, the stronger the bending ability of the light rays; the smaller the absolute value of the optical power, the weaker the bending ability of the light rays. When the optical power is positive, the refraction of the light rays is convergent; when the optical power is negative, the refraction of the light rays is divergent. The optical power can be used to characterize a certain refracting surface of a lens (i.e., a surface of the lens), can be used to characterize a certain lens, or can be used to characterize a system formed by multiple lenses (i.e., a lens group).

[0050] As the first lens group S1 in the macro lens that first adjusts the incident light rays, the setting of its negative optical power can effectively deflect the large-angle incident light rays, ensure that more light rays enter the optical system, and thus can effectively increase the field of view angle of the zoom lens. The second lens group S2 is a positive optical power lens. In this way, the second lens group S2 can timely correct the large aberration generated by the first lens group S1, especially can significantly correct the marginal aberration of the macro lens, thereby improving the imaging resolution of the optical system. Furthermore, the third lens 103, the fourth lens 104, the sixth lens 106, the seventh lens 107, and the ninth lens 109 in the second lens group S2 are positive optical power lenses, and the fifth lens 105 and the eighth lens 108 are negative optical power lenses. The optical powers of the seven lenses in the second lens group S2 cooperate with each other to achieve the setting of the positive optical power of the second lens group S2 and the timely correction of the aberration. As the lens group closest to the image acquisition element in the macro lens, the setting of the negative optical power of the third lens group S3 can ensure that the light rays are better incident on the image acquisition element, and improve the imaging quality of the image acquisition element and the macro lens as a whole.

[0051] In summary, for the macro lens provided by the embodiment of the present invention, during the process of focusing from infinity to close range, the first lens group and the third lens group remain stationary, and the second lens group moves, so that high-performance imaging effects can be achieved for object distances from infinity to a photographic magnification of 2 times. Furthermore, the first lens group includes a first lens and a second lens, the second lens group includes a third lens with positive optical power, a fourth lens with positive optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, a seventh lens with positive optical power, an eighth lens with negative optical power, and a ninth lens with positive optical power, and the third lens group includes a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, and a fourteenth lens. By appropriately setting the composition of each lens group and the optical powers of the lenses in the focusing moving lens group, high-performance imaging effects can be achieved for object distances from infinity to a photographic magnification of 2 times for the macro lens.

[0052] Based on the above embodiments, the macro lens may further include a diaphragm 115 and a filter 116; the diaphragm 115 is disposed in the optical path between the ninth lens 109 and the tenth lens 110; the filter 116 is disposed in the optical path between the fourteenth lens 114 and the image plane.

[0053] Specifically, setting the diaphragm 115 can adjust the propagation direction of the light beam, which is beneficial to improving the imaging quality. And in this macro lens, the diaphragm 115 is located in the optical path between the ninth lens 109 and the tenth lens 110, that is, in the optical path between the second lens group S2 and the third lens group S3. The diaphragm 115 being located in the middle of the macro lens can ensure the minimization of the front and rear apertures of the macro lens.

[0054] The filter 116 is disposed in the optical path between the fourteenth lens 114 and the image plane, and is used to filter out stray light and improve the imaging effect. Specifically, the filter 116 can be an infrared filter.

[0055] Furthermore, the macro lens provided by the embodiment of the present invention may further include a protective glass and an image acquisition element. The protective glass can be disposed on the image side of the filter, and the image acquisition element can be disposed on the image side of the protective glass. The optical system is protected by the protective glass, and the image is acquired by the image acquisition element to realize the normal imaging function of the optical system.

[0056] Based on the above embodiments, in the infinity state, the focal length of the macro lens is F, and the focal length of the second lens group S2 is F 2 ; wherein, 1.68 < F / F 2 < 1.82.

[0057] Specifically, the macro lens focuses by moving the second lens group S2. In order to ensure that the image quality deterioration is small during the focusing process, the focal length of the second lens group S2 and the focal length of the entire optical system satisfy 1.68 < F / F 2 < 1.82. If it exceeds the lower limit of this range, the diopter of the second lens group S2 is too weak, resulting in the inability to meet the focusing state at a 2-fold photographic magnification within the limited length range, and the system image quality difference at different object distances during the focusing process is large, making it difficult to achieve clear imaging at a short object distance. Exceeding the upper limit of this range, the diopter of the second lens group S2 becomes stronger. Although it is easier to meet the in-focus state at different object distances, it will also cause a large aberration in the second lens group S2, which has an adverse effect on the correction of the overall system aberration, and the remaining aberration correction amount that the system needs to bear increases. By reasonably setting the relationship between the focal length of the second lens group S2 and the focal length of the entire optical system, the aberration difference and aberration correction can be taken into account to ensure the imaging quality.

[0058] On the basis of the above embodiments, the movement amount of the second lens group S2 during the focusing process from infinity to close distance is ZOL, and the focal length of the macro lens in the infinity state is F; wherein, 0.54 < ZOL / F < 0.67. This clause restricts the focusing group, that is, the ratio range of the movement range of the second lens group S2 to the focal length of the optical system. Within this constraint clause, it is avoided that the movement range of the focusing group is too small, resulting in difficulty in realizing the focusing process from infinity to close distance and unable to ensure the image quality at close distance. It also avoids that the movement range of the focusing group is too large, resulting in difficulty in compressing the total length of the lens and further reducing the lens volume.

[0059] On the basis of the above embodiments, the overall optical power of the first lens group S1 and the second lens group S2 is Ф 12 , and the optical back focal length of the macro lens is L 后 ; wherein, 0.15 < 100 * (Ф 12 / L 后 ) < 0.22. This clause restricts the relationship between the overall optical power of the first lens group S1 and the second lens group S2 and the optical back focal length. If it exceeds the lower limit of this range, miniaturization will be difficult to achieve. If it exceeds the upper limit of this range, it will be difficult to correct the system aberration, and more lenses will be used to meet the lens performance.

[0060] On the basis of the above embodiments, the eleventh lens 111 and the twelfth lens 112 are adhesively disposed; the optical power of the eleventh lens 111 is ФL 11 , the Abbe number of the eleventh lens 111 is vd11, the optical power of the twelfth lens 112 is ФL 12 , the Abbe number of the twelfth lens 112 is vd12; wherein, 0.6 < 1000 * (ФL 11 / vd11 + ФL 12 / vd12) < 0.85.

[0061] Specifically, the fact that the eleventh lens 111 and the twelfth lens 112 are adhesively bonded can be understood as that the surface of the eleventh lens 111 closer to the image side is attached to the surface of the twelfth lens 112 closer to the object side, that is, the image side surface of the eleventh lens 111 is attached to the object side surface of the twelfth lens 112. By setting the eleventh lens 111 and the twelfth lens 112 to be adhesively bonded, the air gap between the eleventh lens 111 and the twelfth lens 112 can be reduced, which helps to reduce the overall optical length of the lens, and can also reduce the tolerance sensitivity problems such as tilt / eccentricity generated during the assembly of the lens unit, simplify the assembly procedure in the lens manufacturing process, and improve the equipment efficiency. At the same time, when the eleventh lens 111 and the twelfth lens 112 are adhesively bonded, the light loss caused by reflection between the lenses can also be reduced, the illuminance can be improved, and the ghosting risk can be reduced; and the adhesive lens can be used to minimize or eliminate chromatic aberration. Using the adhesive lens in a macro lens can improve the image quality and reduce the reflection loss of light energy, thereby improving the image quality and enhancing the clarity of the lens imaging. Further, the eleventh lens 111 and the twelfth lens 112 can be supported by a spacer, or can be adhesively bonded by glue. The present utility model does not limit the specific adhesive bonding method.

[0062] Further, the optical power ФL of the eleventh lens 111 11 , the Abbe number vd11 of the eleventh lens 111, the optical power ФL of the twelfth lens 112 12 and the Abbe number vd12 of the twelfth lens 112; satisfy 0.6 < 1000*(ФL 11 / vd11 + ФL 12 / vd12) < 0.85. This clause restricts the chromatic aberration of the adhesive lens formed by the eleventh lens 111 and the twelfth lens. Within this restricted range, the chromatic aberration generated by other lenses in the system can be effectively offset, ensuring that the overall chromatic aberration of the system is within a small range.

[0063] On the basis of the above embodiments, both the sixth lens 106 and the ninth lens 109 are ultra-low dispersion lenses. The ultra-low dispersion lens ED (Extra low Dispersion) can promote the actual focusing of light rays of various wavelengths at the same point, can reduce the chromatic aberration generated by the lens and the characteristics of low-dispersion light wavelengths, and then through reasonable material matching with other lenses, thereby reducing chromatic aberration and improving color reproducibility.

[0064] Based on the above embodiments, the clear aperture of the first lens 101 is D1, and the overall optical length of the macro lens is TTL; wherein, 0.19 < D1 / TTL < 0.23. This clause restricts the ratio range of the clear aperture of the first lens to the overall optical length. If the lower limit of this conditional expression is exceeded, the overall lens length will be too long. If the upper limit of this conditional expression is exceeded, the lens volume will be too large, resulting in an increase in lens weight and cost.

[0065] Based on the above embodiments, the second lens 102, the tenth lens 110, and the thirteenth lens 103 are all meniscus lenses. The setting of the meniscus lens can correct the field curvature of the optical system and improve the imaging effect.

[0066] Based on the above embodiments, the first lens 101, the second lens 102, the third lens 103, the fourth lens 104, the fifth lens 105, the sixth lens 106, the seventh lens 107, the eighth lens 108, the ninth lens 109, the tenth lens 110, the eleventh lens 111, the twelfth lens 112, the thirteenth lens 113, and the fourteenth lens 114 are all glass spherical lenses.

[0067] Specifically, the characteristic of a spherical lens is that it has a constant curvature from the center of the lens to the periphery of the lens, ensuring a simple lens setting method. Further, since the lens made of glass material has a small coefficient of thermal expansion and good stability, the first lens 101, the second lens 102, the third lens 103, the fourth lens 104, the fifth lens 105, the sixth lens 106, the seventh lens 107, the eighth lens 108, the ninth lens 109, the tenth lens 110, the eleventh lens 111, the twelfth lens 112, the thirteenth lens 113, and the fourteenth lens 114 can all be glass spherical lenses. The thermal properties of the glass spherical lens are more stable, and when bearing more optical power, it can ensure good resolution ability of the lens within a wide temperature range. In addition, compared with plastic aspherical lenses, the range of glass materials that can be selected is wider, and the refractive index and Abbe number can be selected relatively freely, which can control the high-order aberrations and chromatic aberrations of the lens to a certain extent and meet the usage requirements under complex conditions.

[0068] As a feasible implementation manner, the specific parameters in the macro lens will be described next.

[0069] Table 1 An optical design value of the macro lens in the first embodiment

[0070] Scope of protection Example 1 Lower limit Upper limit F / F2 1.781 1.68 1.82 ZOL / F 0.584 0.54 0.67 <![CDATA[100*(Ф 12 / L 后 )]]> 0.191 0.15 0.22 <![CDATA[1000*(ФL 11 / vd11+ФL 12 / vd12)]]> 0.651 0.60 0.85 D1 / TTL 0.211 0.19 0.23

[0071] Table 2 Design values of the optical physical parameters of a macro lens

[0072]

[0073] The surface numbers in Table 2 are numbered according to the surface order of each lens. "1" represents the object side surface of the first lens, "2" represents the image side surface of the first lens, and so on. "STP" represents the aperture of the lens; the radius of curvature represents the degree of curvature of the lens surface. A positive value indicates that the surface bends towards the image side, and a negative value indicates that the surface bends towards the object side; among them, "INF" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, and the refractive index represents the ability of the material between the current surface and the next surface to deflect light. A space represents that the current position is air and the refractive index is 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface for light.

[0074] Table 3 Focusing data of a macro lens

[0075] Object distance inf Closest 52.179 mm Focal length (mm) 60.62 26.06 S1 38.554 3.155 S2 1.974 37.372

[0076] In Table 3, S1 represents the air gap between the second lens group and the first lens group, and S2 represents the air gap between the second lens group and the third lens group.

[0077] Furthermore, Figure 2 is a schematic diagram of the field curvature and distortion curve of a macro lens under an infinite object distance provided by Embodiment 1 of the present invention. In the left coordinate system in the figure, the horizontal coordinate represents the magnitude of the field curvature, with the unit of mm; the vertical coordinate represents the normalized image height, without a unit; from Figure 2 the left attached figure, it can be seen that the field curvature of the lens provided in this embodiment at each wavelength (435nm, 486nm, 540nm, 588nm, and 656nm respectively) under an infinite object distance is effectively controlled, that is, when imaging, the image quality difference between the center and the periphery is small. In the right coordinate system, the horizontal coordinate represents the magnitude of the distortion, with the unit of %; the vertical coordinate represents the normalized image height, without a unit; from Figure 2 the right attached figure, it can be seen that the maximum distortion of the lens provided in this embodiment is controlled within 5%, the distortion is well corrected, the imaging distortion is small, and the difference between the image and the actual object is small.

[0078] Figure 3 is a schematic diagram of the field curvature and distortion curve of a macro lens under a near object distance provided by Embodiment 1 of the present invention. In the left coordinate system in the figure, the horizontal coordinate represents the magnitude of the field curvature, with the unit of mm; the vertical coordinate represents the normalized image height, without a unit; from Figure 3As can be seen from the left-side attached drawing, the field curvature of the lens provided in this embodiment at an infinite object distance for each wavelength (435nm, 486nm, 540nm, 588nm, and 656nm respectively) is effectively controlled. That is, during imaging, the image quality difference between the center and the periphery is small. In the right-side coordinate system, the horizontal coordinate represents the magnitude of distortion, with the unit of %; the vertical coordinate represents the normalized image height, without a unit; from Figure 3 As can be seen from the right-side attached drawing, the maximum distortion of the lens provided in this embodiment is controlled within 5%, the distortion is well corrected, the imaging distortion is small, and the difference between the image and the actual object is small.

[0079] Figure 4 is a schematic diagram of the lateral chromatic aberration curve of a macro lens under an infinite object distance provided in Embodiment 1 of the present utility model. The horizontal coordinate represents the magnitude of the lateral chromatic aberration, with the unit of μm, and the vertical coordinate represents the image height, with the unit of mm. From Figure 4 it can be seen that the lateral chromatic aberration of the lens provided in this embodiment at different wavelengths (435nm, 486nm, 540nm, 588nm, and 656nm respectively) under an infinite object distance is well controlled, and the imaging chromatic aberration is small.

[0080] Figure 5 is a schematic diagram of the lateral chromatic aberration curve of a macro lens under a near object distance provided in Embodiment 1 of the present utility model. The horizontal coordinate represents the magnitude of the lateral chromatic aberration, with the unit of μm, and the vertical coordinate represents the image height, with the unit of mm. From Figure 5 it can be seen that the lateral chromatic aberration of the lens provided in this embodiment at different wavelengths (435nm, 486nm, 540nm, 588nm, and 656nm respectively) under an infinite object distance is well controlled, and the imaging chromatic aberration is small.

[0081] In summary, the macro lens provided in Embodiment 1 of the present utility model adopts a 14G structure of all glass. By matching the lens materials and reasonably distributing the optical power, a small-sized and low-cost macro lens with a focal length of 60mm is provided, which can achieve high-performance imaging effects for object distances from infinity to 2 times the photographic magnification, and the overall optical length does not exceed 120mm.

[0082] Embodiment 2

[0083] Figure 6 is a schematic diagram of the structure of a macro lens provided in Embodiment 2 of the present utility model, as Figure 6As shown in the figure, the macro lens provided in the second embodiment of the present utility model includes a first lens group S1, a second lens group S2, and a third lens group S3 arranged in sequence along the optical axis from the object plane to the image plane; the first lens group S1 is a negative optical power lens group and the first lens group S1 includes a first lens 101 and a second lens 102; the second lens group S2 is a positive optical power lens group and the second lens group S2 includes a third lens 103, a fourth lens 104, a fifth lens 105, a sixth lens 106, a seventh lens 107, an eighth lens 108, and a ninth lens 109; the third lens 103, the fourth lens 104, the sixth lens 106, the seventh lens 107, and the ninth lens 109 are positive optical power lenses, and the fifth lens 105 and the eighth lens 108 are negative optical power lenses; the third lens group S3 is a negative optical power lens group and the third lens group S3 includes a tenth lens 110, an eleventh lens 111, a twelfth lens 112, a thirteenth lens 113, and a fourteenth lens 114; during the process of focusing from infinity to close range, the second lens group S2 moves along the optical axis towards the object side, and the first lens group S1 and the third lens group S3 are fixed.

[0084] Among them, the setting method of the above lens is the same as that in the first embodiment, and will not be elaborated here.

[0085] As another feasible implementation manner, the specific parameters in the macro lens will be described below.

[0086] Table 4 An optical design value of the macro lens in the second embodiment

[0087] Scope of protection Example 2 Lower limit Upper limit F / F2 1.767 1.68 1.82 ZOL / F 0.610 0.54 0.67 <![CDATA[100*(Ф 12 / L 后 )]]> 0.187 0.15 0.22 <![CDATA[1000 * (ФL 11 / vd11 + ФL 12 / vd12)]]> 0.804 0.60 0.85 D1 / TTL 0.205 0.19 0.23

[0088] Table 5 Design values of the optical physical parameters of a macro lens

[0089]

[0090] The surface numbers in Table 5 are numbered according to the surface order of each lens. "1" represents the object side surface of the first lens, "2" represents the image side surface of the first lens, and so on. "STP" represents the aperture stop of the lens; the radius of curvature represents the degree of curvature of the lens surface. A positive value represents that the surface bends towards the image side, and a negative value represents that the surface bends towards the object side; among them, "INF" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, a space represents that the current position is air and the refractive index is 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface for light.

[0091] Table 6 Focusing data of a macro lens

[0092] Object distance inf Closest 52.382 mm Focal length (mm) 60.61 22.58 S1 37.908 0.944 S2 1.997 38.961

[0093] In Table 6, S1 represents the air gap between the second lens group and the first lens group, and S2 represents the air gap between the second lens group and the third lens group.

[0094] Furthermore, Figure 7 It is a schematic diagram of the field curvature and distortion curve of a macro lens under an infinite object distance provided in the second embodiment of the present invention. In the left coordinate system of the figure, the horizontal coordinate represents the magnitude of the field curvature, with the unit of mm; the vertical coordinate represents the normalized image height, without a unit; from Figure 7 As can be seen from the left attached figure, the field curvature of the lens provided in this embodiment at each wavelength (435nm, 486nm, 540nm, 588nm, and 656nm respectively) under an infinite object distance is effectively controlled, that is, when imaging, the image quality difference between the center and the periphery is small. In the right coordinate system, the horizontal coordinate represents the magnitude of the distortion, with the unit of %; the vertical coordinate represents the normalized image height, without a unit; from Figure 7 As can be seen from the right attached figure, the maximum distortion of the lens provided in this embodiment is controlled within 5%, the distortion is well corrected, the imaging distortion is small, and the difference between the image and the actual object is small.

[0095] Figure 8 It is a schematic diagram of the field curvature and distortion curve of a macro lens under a near object distance provided in the second embodiment of the present invention. In the left coordinate system of the figure, the horizontal coordinate represents the magnitude of the field curvature, with the unit of mm; the vertical coordinate represents the normalized image height, without a unit; from Figure 8 As can be seen from the left attached figure, the field curvature of the lens provided in this embodiment at each wavelength (435nm, 486nm, 540nm, 588nm, and 656nm respectively) under an infinite object distance is effectively controlled, that is, when imaging, the image quality difference between the center and the periphery is small. In the right coordinate system, the horizontal coordinate represents the magnitude of the distortion, with the unit of %; the vertical coordinate represents the normalized image height, without a unit; from Figure 8 As can be seen from the right attached figure, the maximum distortion of the lens provided in this embodiment is controlled within 5%, the distortion is well corrected, the imaging distortion is small, and the difference between the image and the actual object is small.

[0096] Figure 9 It is a schematic diagram of the lateral chromatic aberration curve of a macro lens under an infinite object distance provided in the second embodiment of the present invention. The horizontal coordinate represents the magnitude of the lateral chromatic aberration, with the unit of μm, and the vertical coordinate represents the image height, with the unit of mm. From Figure 9 It can be seen that the lateral chromatic aberration of the lens provided in this embodiment at different wavelengths (435nm, 486nm, 540nm, 588nm, and 656nm respectively) under an infinite object distance is well controlled, and the imaging chromatic aberration is small.

[0097] Figure 10It is a schematic diagram of the lateral chromatic aberration curve of a macro lens with a short object distance under a microscope provided in the second embodiment of the present invention. The horizontal coordinate represents the magnitude of the lateral chromatic aberration, with the unit of μm, and the vertical coordinate represents the image height, with the unit of mm. From Figure 10 It can be seen that the lateral chromatic aberration of the lens provided in this embodiment at different wavelengths (435nm, 486nm, 540nm, 588nm, and 656nm respectively) at an infinite object distance is well controlled, and the imaging chromatic aberration is small.

[0098] In summary, the macro lens provided in the second embodiment of the present invention adopts an all-glass 14G structure. By matching the lens materials and reasonably distributing the optical power, it provides a small-sized and low-cost macro lens with a focal length of 60mm, capable of achieving high-performance imaging effects at object distances from infinity to 2 times the photographic magnification, and the overall optical length not exceeding 120mm.

[0099] Embodiment Three

[0100] Figure 11 It is a schematic diagram of the structure of a macro lens provided in the third embodiment of the present invention. As Figure 11 shown, the macro lens provided in the third embodiment of the present invention includes a first lens group S1, a second lens group S2, and a third lens group S3 arranged in sequence along the optical axis from the object plane to the image plane; the first lens group S1 is a negative optical power lens group and the first lens group S1 includes a first lens 101 and a second lens 102; the second lens group S2 is a positive optical power lens group and the second lens group S2 includes a third lens 103, a fourth lens 104, a fifth lens 105, a sixth lens 106, a seventh lens 107, an eighth lens 108, and a ninth lens 109; the third lens 103, the fourth lens 104, the sixth lens 106, the seventh lens 107, and the ninth lens 109 are positive optical power lenses, and the fifth lens 105 and the eighth lens 108 are negative optical power lenses; the third lens group S3 is a negative optical power lens group and the third lens group S3 includes a tenth lens 110, an eleventh lens 111, a twelfth lens 112, a thirteenth lens 113, and a fourteenth lens 114; during the process of focusing from infinity to a close distance, the second lens group S2 moves axially towards the object side, and the first lens group S1 and the third lens group S3 are fixed.

[0101] Among them, the setting method of the above lens is the same as that in Embodiment One, and will not be elaborated here.

[0102] As another feasible implementation manner, the specific parameters of the macro lens will be described below.

[0103] Table 7 An optical design value of the macro lens in Embodiment Three

[0104] Scope of protection Example 3 Lower limit Upper limit F / F2 1.787 1.68 1.82 ZOL / F 0.630 0.54 0.67 <![CDATA[100*(Ф 12 / L 后 )]]> 0.177 0.15 0.22 <![CDATA[1000*(ФL 11 / vd11+ФL 12 / vd12)]]> 0.676 0.60 0.85 D1 / TTL 0.208 0.19 0.23

[0105] Table 8 Design Values of Optical Physical Parameters of a Macro Lens

[0106]

[0107] The surface numbers in Table 8 are numbered according to the surface order of each lens. "1" represents the object-side surface of the first lens, "2" represents the image-side surface of the first lens, and so on. "STP" represents the aperture of the lens; the radius of curvature represents the degree of curvature of the lens surface. A positive value indicates that the surface bends towards the image side, and a negative value indicates that the surface bends towards the object side; where "INF" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and the space represents that the current position is air and the refractive index is 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface for light.

[0108] Table 9 Focusing Data of a Macro Lens

[0109] Object distance inf Closest 53.144 mm Focal length (mm) 60.60 25.56 S1 39.155 0.949 S2 1.998 40.203

[0110] In Table 9, S1 represents the air gap between the second lens group and the first lens group, and S2 represents the air gap between the second lens group and the third lens group.

[0111] Furthermore, Figure 12 is a schematic diagram of the field curvature and distortion curves of a macro lens under an infinite object distance provided in Embodiment 3 of the present invention. In the left coordinate system in the figure, the horizontal coordinate represents the magnitude of the field curvature, with the unit of mm; the vertical coordinate represents the normalized image height, without a unit; from Figure 12 the left attached figure, it can be seen that the field curvature of the lens provided in this embodiment at each wavelength (435nm, 486nm, 540nm, 588nm, and 656nm respectively) under an infinite object distance is effectively controlled, that is, when imaging, the image quality difference between the center and the periphery is small. In the right coordinate system, the horizontal coordinate represents the magnitude of the distortion, with the unit of %; the vertical coordinate represents the normalized image height, without a unit; from Figure 12 the right attached figure, it can be seen that the maximum distortion of the lens provided in this embodiment is controlled within 5%, the distortion is well corrected, the imaging distortion is small, and the difference between the image and the actual object is small.

[0112] Figure 13 is a schematic diagram of the field curvature and distortion curves of a macro lens under a near object distance provided in Embodiment 3 of the present invention. In the left coordinate system in the figure, the horizontal coordinate represents the magnitude of the field curvature, with the unit of mm; the vertical coordinate represents the normalized image height, without a unit; from Figure 13As can be seen from the left-side attached figure, the field curvature of the lens provided in this embodiment at an infinite object distance for each wavelength (435nm, 486nm, 540nm, 588nm, and 656nm respectively) is effectively controlled. That is, during imaging, the image quality difference between the center and the periphery is small. In the right-side coordinate system, the horizontal coordinate represents the magnitude of distortion, with the unit of %; the vertical coordinate represents the normalized image height, without a unit; by Figure 13 As can be seen from the right-side attached figure, the maximum distortion of the lens provided in this embodiment is controlled within 5%, the distortion is well corrected, the imaging distortion is small, and the difference between the image and the actual object is small.

[0113] Figure 14 It is a schematic diagram of the lateral chromatic aberration curve of a macro lens under an infinite object distance provided in Embodiment 3 of the present utility model. The horizontal coordinate represents the magnitude of the lateral chromatic aberration, with the unit of μm, and the vertical coordinate represents the image height, with the unit of mm. By Figure 14 As can be seen, the lateral chromatic aberration of the lens provided in this embodiment at different wavelengths (435nm, 486nm, 540nm, 588nm, and 656nm respectively) under an infinite object distance is well controlled, and the imaging chromatic aberration is small.

[0114] Figure 15 It is a schematic diagram of the lateral chromatic aberration curve of a macro lens under a near object distance provided in Embodiment 3 of the present utility model. The horizontal coordinate represents the magnitude of the lateral chromatic aberration, with the unit of μm, and the vertical coordinate represents the image height, with the unit of mm. By Figure 15 As can be seen, the lateral chromatic aberration of the lens provided in this embodiment at different wavelengths (435nm, 486nm, 540nm, 588nm, and 656nm respectively) under an infinite object distance is well controlled, and the imaging chromatic aberration is small.

[0115] In summary, the macro lens provided in Embodiment 3 of the present utility model adopts an all-glass 14G structure. By matching the lens materials and reasonably distributing the optical power, it provides a small-sized and low-cost macro lens with a focal length of 60mm, capable of achieving high-performance imaging effects for object distances from infinity to 2 times the photographic magnification, and the overall optical length not exceeding 120mm.

[0116] The above specific embodiments do not constitute a limitation to the protection scope of the present utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A macro lens, characterized in that: It includes a first lens group, a second lens group and a third lens group which are arranged in sequence from the object plane to the image plane along the optical axis; The first lens group is a negative power lens group and includes a first lens and a second lens; The second lens group is a positive power lens group and includes a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens; the third lens, the fourth lens, the sixth lens, the seventh lens and the ninth lens are positive power lenses, and the fifth lens and the eighth lens are negative power lenses; The third lens group is a negative power lens group and includes a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens and a fourteenth lens; In the process of focusing from infinity to close distance, the second lens group moves along the optical axis toward the object side, and the first lens group and the third lens group are fixed.

2. The macro lens according to claim 1, characterized in that: In the infinite state, the focal length of the macro lens is F, and the focal length of the second lens group is F2; Among them, 1.68 <F / F2<1.82。 3. The macro lens according to claim 1, characterized in that: The movement amount of the second lens group from infinity to close-range focusing is ZOL, and the focal length of the macro lens in the infinity state is F; Among them, 0.54 <ZOL / F<0.67。 4. The macro lens according to claim 1, characterized in that: The overall focal power of the first lens group and the second lens group is Φ 12 , the optical back focus of the macro lens is L 后 ; Among them, 0.15<100*(Ф 12 / L 后 )<0.

22.

5. The macro lens according to claim 1, characterized in that: The eleventh lens and the twelfth lens are cemented together; The focal power of the eleventh lens is ФL 11 The Abbe constant of the eleventh lens is vd11, and the focal power of the twelfth lens is ФL 12 , the Abbe constant of the twelfth lens is vd12; Among them, 0.6<1000*(ФL 11 / vd11+ФL 12 / vd12)<0.

85.

6. The macro lens according to claim 1, characterized in that: The sixth lens and the ninth lens are both extra-low dispersion lenses.

7. The macro lens according to claim 1, characterized in that: The aperture of the first lens is D1, and the total optical length of the macro lens is TTL; Among them, 0.19 <D1 / TTL<0.23。 8. The macro lens according to claim 1, characterized in that: The second lens, the tenth lens and the thirteenth lens are all meniscus lenses.

9. The macro lens according to claim 1, characterized in that: The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, the twelfth lens, the thirteenth lens and the fourteenth lens are all glass spherical lenses.

10. The macro lens according to claim 1, characterized in that: The macro lens also includes an aperture and a filter; The aperture is arranged in the optical path between the ninth lens and the tenth lens; The filter is arranged in the optical path between the fourteenth lens and the image plane.

Images