A full-spherical high-magnification lens

Abstract

The present invention discloses a full-spherical high-power lens, which is characterized in that it includes, from the object side to the image side, a first lens group with positive focal power; a second lens group with negative focal power; an aperture stop; a third lens group with positive focal power; a fourth lens group with positive focal power; and a fifth lens group with positive focal power, wherein the first lens group to the fifth lens group are all composed of spherical lenses, the second lens group and the fourth lens group are both movable, so that the zooming from the wide-angle end to the telephoto end is achieved by moving the two along the optical axis, and the fifth lens group is movable so that the fifth lens group is moved along the optical axis to correct the defocus caused by the zooming process and the change of the object distance. The present invention overcomes the problems of low clarity and deformation of the full-spherical lens, which makes it difficult to ensure the imaging quality of the lens and the difficulty of the lens performance reaching the 4M level standard, and provides a full-spherical high-power lens.

Description

Technical field

[0001] The invention relates to a spherical high-magnification lens. [Background Technology]

[0002] Spherical lenses have a spherical surface. When light of different wavelengths strikes the lens at different locations parallel to the optical axis, aberrations can occur, affecting image quality and causing issues such as reduced clarity and distortion. Adding corrective lenses can address these issues, but this further impairs image quality and increases the size and weight of the lens. Consequently, high-magnification lenses currently on the market often utilize aspherical lenses to achieve higher clarity, while also saving space and reducing lens size. However, aspherical lenses are expensive to manufacture and complex to inspect. This low efficiency and high cost hinder product adoption. Consequently, companies often use spherical lenses as optical elements for lenses with limited production runs and high yield requirements. However, due to the low clarity and distortion associated with spherical lenses, image quality is difficult to guarantee, making it difficult for lenses to meet 4M performance standards.

[0003] The present invention is just based on above deficiency and produces. [Summary of the invention]

[0004] The purpose of the present invention is to overcome the shortcomings of the existing technology and propose a full-spherical high-magnification lens that has a front 10x infrared confocality while maintaining the existing volume. It has the characteristics of low cost, high magnification, fast focusing, etc., and has good performance in the entire focal length range, and can correspond to 4M-level image photography solid-state camera elements.

[0005] The present invention is achieved through the following technical solutions:

[0006] A spherical high-magnification lens, characterized in that it includes, from the object side to the image side, the following: a first lens group G1 having positive focal power; a second lens group G2 having negative focal power; an aperture stop S; a third lens group G3 having positive focal power; a fourth lens group G4 having positive focal power; and a fifth lens group G5 having positive focal power; wherein, the first lens group G1 to the fifth lens group G5 are all composed of spherical lenses, the second lens group G2 and the fourth lens group G4 are both movable, so that by moving along the optical axis, the magnification change from the wide-angle end to the telephoto end can be achieved, and the fifth lens group G5 is movable so that by moving along the optical axis, the fifth lens group G5 can correct the defocus caused by the magnification change process and the change in object distance.

[0007] The global high-magnification lens as described above is characterized in that the first lens group G1 includes, from the object side, a first lens 1 with negative optical power, a second lens 2 with positive optical power, a third lens 3 with positive optical power, a fourth lens 4 with positive optical power, and a fifth lens 5 with negative optical power, wherein the first lens 1 and the second lens 2 are combined into a cemented lens, and the fourth lens 4 and the fifth lens 5 are combined into a cemented lens.

[0008] The global high-power lens as described above is characterized in that the second lens group G2 includes, from the object side to the image side, a sixth lens 6 with negative focal power, a seventh lens 7 with negative focal power, an eighth lens 8 with positive focal power, and a ninth lens 9 with negative focal power, wherein the seventh lens 7 and the eighth lens 8 are combined into a cemented lens, and the third lens group G3 includes, from the object side, a tenth lens 10 with positive focal power, an eleventh lens 11 with positive focal power, a twelfth lens 12 with negative focal power, a thirteenth lens 13 with positive focal power, a thirteenth lens 14 with positive focal power, and a ninth lens 15 with positive focal power. The fourth lens group G4 includes, from the object side, a fifteenth lens 15 with negative focal power, a sixteenth lens 16 with positive focal power, a seventeenth lens 17 with negative focal power, and an eighteenth lens 18 with positive focal power, the seventeenth lens 17 and the eighteenth lens 18 being combined into a cemented lens, satisfying the following conditions: Nd6>1.85; Nd9>1.85; Nd15>1.85; Nd16>1.85; Nd12-Nd13<0.3; wherein Nd6, Nd9, Nd12, Nd13, Nd15, and Nd16 are the refractive indices of the sixth lens 6, the ninth lens 9, the twelfth lens 12, the thirteenth lens 13, the fifteenth lens 15, and the sixteenth lens 16, respectively.

[0009] The spherical high-magnification lens as described above is characterized in that it satisfies the following conditions: 3<ft1 / f1<4; -4<f001 / ft<-2.5; wherein ft1 is the focal length of the first lens group G1 at the telephoto end, f1 is the focal length of the first lens group, f001 is the focal length of the first lens 1, and ft is the focal length of the entire system at the telephoto end.

[0010] The spherical high-magnification lens as described above is characterized by satisfying the following conditions: 1.5<f006 / f2<3;18<fw / L1-2<22;4.5<ft-fw / Lt-w<5.5

[0011] Among them, f006 is the focal length of the sixth lens 6, f2 is the focal length of the second lens group G2, fw is the focal length of the entire system at the wide-angle end, ft is the focal length of the entire system at the telephoto end, L1-2 is the distance between the first lens group G2 and the second lens group G2 at the wide-angle end, and Lt-w is the moving distance of the lens group of the entire system from the wide-angle end to the telephoto end.

[0012] The spherical high-magnification lens as described above is characterized in that it satisfies the following conditions: 2.5<f010 / fw<4; 2.5<fw / f3<4; 3.5<ft / L1-3<4.5; wherein f010 is the focal length of the tenth lens 10, fw is the focal length of the entire system at the wide-angle end, f3 is the focal length of the third lens group G3, ft is the focal length of the entire system at the telephoto end, and L1-3 is the distance from the first lens group G1 to the third lens group G3.

[0013] The spherical high-magnification lens as described above is characterized in that it satisfies the following conditions: 3.8<ft4-fw4 / f4<5.2; 1.4<f4 / f3<2; wherein ft4 is the focal length of the fourth lens group G4 at the telephoto end, fw4 is the focal length of the fourth lens group G4 at the wide-angle end, f4 is the focal length of the fourth lens group G4, and f3 is the focal length of the third lens group G3.

[0014] The spherical high-magnification lens as described above is characterized in that it satisfies the condition: 0.1<fw5 / f5<0.3; wherein fw5 is the focal length of the fifth lens group G5 at the wide-angle end, and f5 is the focal length of the fifth lens group G5.

[0015] The spherical high-magnification lens as described above is characterized in that the fifth lens group G5 includes a nineteenth lens 19 with positive optical power, and the nineteenth lens 19 is a lens made of extra-low dispersion glass.

[0016] The spherical high-magnification lens as described above is characterized in that the aperture stop S adopts P-IRIS, which has a hole with a shape approximately circular.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The present invention achieves zooming from the wide-angle end to the telephoto end by moving the second lens group along the optical axis from the object side to the image side, while simultaneously moving the fourth lens group along the optical axis, with the position of the lens group on the optical axis corresponding to the position of the second lens group. Simultaneously, by moving the fifth lens group along the optical axis, the system corrects for defocus caused by changes in zooming and object distance, ensuring that the image remains clear throughout the zooming process. Furthermore, the third lens group of the present invention can be configured as a fixed group, and then its structure can be modified as needed to allow the lens group to tilt or slightly move perpendicular to the optical axis to compensate for lens shake and ensure image stability, thereby achieving an anti-shake function for the entire lens system. This allows for the production of a low-cost, high-performance, high-magnification lens while maintaining a relatively small overall lens volume.

[0019] 2. The lens of the present invention, wherein the fifth lens group includes a nineteenth lens having positive optical power, wherein the nineteenth lens is made of extra-low dispersion glass. The use of extra-low dispersion glass material can significantly tighten the red and purple light at the telephoto end of the lens, so that the lens can provide a sharper color experience.

[0020] 3. The lens of this invention uses a P-IRIS aperture diaphragm, which is approximately circular in shape. This avoids the flaw of a cat's eye aperture that exhibits low true circularity when the aperture is reduced, achieving balanced and uniform image quality in both the sagittal and tangential directions in all conditions.

Brief Description of the Drawings

[0021] Figure 1 is a schematic structural diagram of a first embodiment of the present invention;

[0022] Figure 2 is a schematic structural diagram of a second embodiment of the present invention;

[0023] Figure 3 Aberration diagrams of the first embodiment with respect to the e-line at the wide-angle end;

[0024] Figure 4 Aberration diagrams of the first embodiment with respect to the e-line at the wide-angle end;

[0025] Figure 5 Aberration diagrams of the first embodiment at the telephoto end with respect to the e-line;

[0026] Figure 6 Aberration diagrams of the first embodiment at the telephoto end with respect to the e-line;

[0027] Figure 7 Aberration diagrams of the second embodiment at the wide-angle end with respect to the e-line;

[0028] Figure 8 Aberration diagrams of the second embodiment at the wide-angle end with respect to the e-line;

[0029] Figure 9 Aberration diagrams of the second embodiment at the telephoto end with respect to the e-line;

[0030] Figure 10 These are aberration diagrams for the second embodiment at the telephoto end with respect to the e-line. [Specific implementation method]

[0031] The present invention will be further described below in conjunction with the accompanying drawings:

[0032] The following is a first embodiment.

[0033] like Figure 1 As shown, a spherical high-magnification lens is characterized in that it includes, from the object side to the image side,: a first lens group G1 with positive focal power; a second lens group G2 with negative focal power; an aperture stop S; a third lens group G3 with positive focal power; a fourth lens group G4 with positive focal power; and a fifth lens group G5 with positive focal power; wherein, the first lens group G1 to the fifth lens group G5 are all composed of spherical lenses, the second lens group G2 and the fourth lens group G4 are both movable, so that the magnification change from the wide-angle end to the telephoto end can be achieved by moving the two along the optical axis, and the fifth lens group G5 is movable so that the fifth lens group G5 moves along the optical axis to correct the defocus caused by the magnification change process and the change of object distance. When the lens is transmitting light, by moving the second lens group G2 along the optical axis from the object side to the image side, and simultaneously moving the fourth lens group G4 along the optical axis, the positions of the fourth lens group G4 and the second lens group G2 on the optical axis correspond to each other, thereby achieving zooming from the wide-angle end to the telephoto end. At the same time, by moving the fifth lens group G5 along the optical axis, the system corrects the defocus caused by the zoom process and the change in object distance, ensuring that the image remains clear during the zoom process. In addition, because the third lens group G3 is configured as a fixed group, the structure can be changed as needed so that the lens group can be tilted or slightly moved perpendicular to the optical axis to compensate for lens shake and ensure image stability, thereby achieving the anti-shake function of the entire lens system. Under the premise of the overall lens volume being small, a low-cost, high-performance high-magnification lens can be produced.

[0034] The global high-magnification lens as described above is characterized in that: the first lens group G1 includes, from the object side, in order: a first lens 1 with negative optical power, a second lens 2 with positive optical power, a third lens 3 with positive optical power, a fourth lens 4 with positive optical power, and a fifth lens 5 with negative optical power, wherein the first lens 1 and the second lens 2 are combined into a cemented lens, and the fourth lens 4 and the fifth lens 5 are combined into a cemented lens. In this way, by combining the different refractive indices and Abbe numbers of the lens materials, the transition of peripheral chromatic aberration of the lens is ensured.

[0035] The global high-power lens as described above is characterized in that the second lens group G2 includes, from the object side to the image side, a sixth lens 6 with negative focal power, a seventh lens 7 with negative focal power, an eighth lens 8 with positive focal power, and a ninth lens 9 with negative focal power, wherein the seventh lens 7 and the eighth lens 8 are combined into a cemented lens, and the third lens group G3 includes, from the object side, a tenth lens 10 with positive focal power, an eleventh lens 11 with positive focal power, a twelfth lens 12 with negative focal power, a thirteenth lens 13 with positive focal power, a thirteenth lens 14 with positive focal power, and a ninth lens 15 with positive focal power. The fourth lens group G4 includes, from the object side, a fifteenth lens 15 with negative focal power, a sixteenth lens 16 with positive focal power, a seventeenth lens 17 with negative focal power, and an eighteenth lens 18 with positive focal power, the seventeenth lens 17 and the eighteenth lens 18 being combined into a cemented lens, satisfying the following conditions: Nd6>1.85; Nd9>1.85; Nd15>1.85; Nd16>1.85; Nd12-Nd13<0.3; wherein Nd6, Nd9, Nd12, Nd13, Nd15, and Nd16 are the refractive indices of the sixth lens 6, the ninth lens 9, the twelfth lens 12, the thirteenth lens 13, the fifteenth lens 15, and the sixteenth lens 16, respectively. The fifteenth lens 15 and the sixteenth lens 16 are formed by cementing a negative power lens and a positive power lens to effectively reduce the chromatic aberration of magnification. The refractive index of the fifteenth lens 15 and the sixteenth lens 16 both satisfy Nd>1.85, and they are respectively matched as positive and negative lenses, which effectively changes the effective aperture of the light. At the same time, the light deflection angle is not large, so that the aberration is effectively compensated and improved.

[0036] The spherical high-magnification lens as described above is characterized by satisfying the conditional expression:

[0037] 3<ft1 / f1<4

[0038] -4<f001 / ft1<-2.5

[0039] Among them, ft1 is the focal length of the first lens group G1 at the telephoto end, f1 is the focal length of the first lens group, f001 is the focal length of the first lens 1, and ft is the focal length of the entire system at the telephoto end.

[0040] The spherical high-magnification lens as described above is characterized by satisfying the conditional expression:

[0041] 1.5<f006 / f2<3

[0042] 18<fw / L1-2<22

[0043] 4.5<(ft-fw) / Lt-w<5.5

[0044] Among them, f006 is the focal length of the sixth lens 6, f2 is the focal length of the second lens group G2, fw is the focal length of the entire system at the wide-angle end, ft is the focal length of the entire system at the telephoto end, L1-2 is the distance between the first lens group G2 and the second lens group G2 at the wide-angle end, and Lt-w is the moving distance of the lens group of the entire system from the wide-angle end to the telephoto end.

[0045] The spherical high-magnification lens as described above is characterized by satisfying the conditional expression:

[0046] 2.5<f010 / fw<4

[0047] 2.5<fw / f3<4

[0048] 3.5<ft / L1-3<4.5

[0049] Wherein, f010 is the focal length of the tenth lens 10, fw is the focal length of the entire system at the wide-angle end, f3 is the focal length of the third lens group G3, ft is the focal length of the entire system at the telephoto end, and L1-3 is the distance from the first lens group G1 to the third lens group G3.

[0050] The spherical high-magnification lens as described above is characterized by satisfying the conditional expression:

[0051] 3.8<(ft4-fw4) / f4<5.2

[0052] 1.4<f4 / f3<2

[0053] Among them, ft4 is the focal length of the fourth lens group G4 at the telephoto end, fw4 is the focal length of the fourth lens group G4 at the wide-angle end, f4 is the focal length of the fourth lens group G4, and f3 is the focal length of the third lens group G3.

[0054] The spherical high-magnification lens as described above is characterized by satisfying the conditional expression:

[0055] 0.1<fw5 / f5<0.3

[0056] Among them, fw5 is the focal length of the fifth lens group G5 at the wide-angle end, and f5 is the focal length of the fifth lens group G5.

[0057] The spherical high-magnification lens as described above is characterized in that: the fifth lens group G5 includes a nineteenth lens 19 with positive optical power, and the nineteenth lens 19 is a lens made of extra-low dispersion glass. The use of extra-low dispersion glass material can significantly tighten the red light and purple light at the telephoto end of the lens, so that the lens can obtain a sharper color experience.

[0058] The spherical high-magnification lens described above is characterized in that the aperture stop 6 utilizes a P-IRIS, and the aperture shape is approximately circular. This avoids the defect of a cat's eye aperture having a low true roundness when the aperture is reduced, thereby achieving balanced and uniform image quality in both the sagittal and tangential directions in all states.

[0059] The numerical data of the first embodiment are as follows:

[0060] EFL=10.6 at wide angle to 329.4 at telephoto

[0061] F No.=2.15 at wide angle~5.8 at telephoto

[0062] Where EFL is the effective focal length of the entire system, and FNo. is the ratio of the effective focal length (EFL) to the aperture diameter.

[0063] The following table shows the structural parameters of the first embodiment, S1 to S36 respectively represent Figure 1 The units of curvature radius and thickness of each lens surface are shown in mm. Figure 1 The IMG shown is the image plane, which is generally a solid-state imaging element such as CCD or CMOS.

[0064] Surface serial number Surface type Radius of curvature thickness Refractive index Abbe number S1 spherical surface 815.597 1.5 1.72 29.51 S2 spherical surface 129.925 6.05 1.50 81.61 S3 spherical surface -271.621 0.07 S4 spherical surface 114.792 5.05 1.59 68.62 S5 spherical surface INF 0.07 S6 spherical surface 87.784 6.22 1.50 81.61 S7 spherical surface -1156.087 1.5 1.71 53.87 S8 spherical surface 300.77 A S9 spherical surface 293.704 0.8 1.88 39.23 S10 spherical surface 34.847 3.21 S11 spherical surface -146.027 0.7 1.71 53.87 S12 spherical surface 22.815 5.65 2.00 25.44 S13 spherical surface -173.571 2.36 S14 spherical surface -55.519 0.8 1.91 35.26 S spherical surface 55.519 B S spherical surface INF 0.3 S17 spherical surface 24.145 3.1 1.59 68.62 S18 spherical surface -70.696 0.06 S19 spherical surface 16.552 3.95 1.50 81.61 S20 spherical surface -44.061 0.7 2.00 25.44 S21 spherical surface 21.043 0.06 S22 spherical surface 17.642 2.35 1.95 17.94 S23 spherical surface INF 0.65 S24 spherical surface 67.011 0.95 1.70 30.05 S25 spherical surface 10.806 C S26 spherical surface -19.018 0.8 1.88 39.23 S27 spherical surface 19.018 2.05 S28 spherical surface 29.702 5.87 2.00 25.44 S29 spherical surface -49.609 4.92 S30 spherical surface 77.639 5.29 1.78 25.72 S31 spherical surface 16.13 4.53 1.59 68.62 S32 spherical surface -23.123 D S33 spherical surface 23.803 2.88 1.50 81.61 S34 spherical surface -127.188 E S35 spherical surface INF 1 1.52 64.21 S36 spherical surface INF 0.7 IMG spherical surface INF \

[0065] The following table shows the lens zoom parameters of the first embodiment.

[0066] Surface serial number W T A 0.5 66.86 B 69.36 3.00 C 5.07 33.38 D 13.15 1.10 E 17.88 1.62

[0067] The following is a second embodiment.

[0068] The numerical data of the second embodiment are as follows:

[0069] EFL=10.6 at wide angle to 330 at telephoto

[0070] F No.=2.0 at wide angle to 5.8 at telephoto

[0071] Where EFL is the effective focal length of the entire system, and FNo. is the ratio of the effective focal length (EFL) to the aperture diameter.

[0072] The following table shows the structural parameters of the second embodiment, S1 to S36 respectively represent Figure 2 For each lens surface shown, the unit of the radius of curvature is mm, and the unit of the thickness is mm.

[0073] Surface serial number Surface type Radius of curvature thickness Refractive index Abbe number S1 spherical surface INF 1.5 1.72 29.51 S2 spherical surface 187.130 5.57 1.50 81.61 S3 spherical surface -337.055 0.07 S4 spherical surface 99.911 7.32 1.59 68.62 S5 spherical surface -380.119 0.07 S6 spherical surface 80.317 8.35 1.50 81.61 S7 spherical surface -225.195 1.5 1.71 53.87 S8 spherical surface 179.036 A S9 spherical surface 166.786 0.8 1.88 39.23 S10 spherical surface 40.109 3.50 S11 spherical surface -73.822 0.7 1.71 53.87 S12 spherical surface 23.775 4.71 2.00 25.44 S13 spherical surface -248.889 0.69 S14 spherical surface -101.055 0.8 1.88 39.23 S15 spherical surface 35.850 B S spherical surface INF 0.3 S17 spherical surface 19.381 2.75 1.59 68.62 S18 spherical surface -259.913 0.06 S19 spherical surface 18.053 2.97 1.50 81.61 S20 spherical surface -60.248 0.7 2.00 25.44 S21 spherical surface 72.059 0.06 S22 spherical surface 17.353 2.25 1.95 17.94 S23 spherical surface 627.316 0.25 S24 spherical surface 495.798 0.4 2.00 25.44 S25 spherical surface 10.994 C S26 spherical surface -55.5694 0.8 1.88 39.23 S27 spherical surface 15.706 6.07 S28 spherical surface 35.607 2.27 2.00 25.44 S29 spherical surface -70.336 11.79 S30 spherical surface 396.421 0.6 1.78 25.72 S31 spherical surface 17.036 4.68 1.59 68.62 S32 spherical surface -24.054 D S33 spherical surface 25.54 2.76 1.50 81.61 S34 spherical surface -130 E S35 spherical surface INF 1 1.52 64.21 S36 spherical surface INF 2.6 IMG spherical surface INF \

[0074] The following table shows the lens zoom parameters of the first embodiment.

[0075] Surface serial number W T A 0.5 64.07 B 66.14 2.57 C 2.96 31.18 D 14.42 1 E 18.10 3.3

[0076] Other structural parameters of the second embodiment are consistent with those of the first embodiment.

[0077] In addition, if Figure 1 The IR-CUT shown is an electromagnetically driven switching sheet, which consists of a red sheet or a blue sheet and a transparent anti-reflection sheet. The red sheet or the blue sheet is used to filter out unnecessary wavelengths of light and stray light. It is generally used during the day and will automatically switch to the transparent anti-reflection sheet at night. The transparent sheet is highly transparent to both visible and infrared light. High transparency means high transmittance, so that when the light is weak, an infrared light source can be used to compensate for insufficient lighting at night.

[0078] The present invention is not limited to the above-mentioned embodiments, and its form and structure can be changed in other forms. The above-mentioned specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principles and purpose of the present invention. The scope of protection of the present invention is based on the claims and is not limited by the above-mentioned specific implementation. All implementation schemes within its scope are subject to the constraints of the present invention.

Claims

1. A spherical high-magnification lens, characterized in that: The lens is composed of, from the object side to the image side, a first lens group (G1) with positive power, a second lens group (G2) with negative power, an aperture stop (S), a third lens group (G3) with positive power, a fourth lens group (G4) with positive power, and a fifth lens group (G5) with positive power; The first lens group (G1) to the fifth lens group (G5) are all composed of spherical lenses, the second lens group (G2) and the fourth lens group (G4) are both movable, so that the zooming from the wide-angle end to the telephoto end is achieved by moving the two along the optical axis, and the fifth lens group (G5) is movable so that the fifth lens group (G5) moves along the optical axis to correct the defocus caused by the zooming process and the change of the object distance; The first lens group (G1) is composed of, from the object side, a first lens (1) with negative optical power, a second lens (2) with positive optical power, a third lens (3) with positive optical power, a fourth lens (4) with positive optical power, and a fifth lens (5) with negative optical power, wherein the first lens (1) and the second lens (2) are combined into a cemented lens, and the fourth lens (4) and the fifth lens (5) are combined into a cemented lens; The second lens group (G2) is composed of, from the object side to the image side, a sixth lens (6) with negative focal power, a seventh lens (7) with negative focal power, an eighth lens (8) with positive focal power and a ninth lens (9) with negative focal power, wherein the seventh lens (7) and the eighth lens (8) are combined into a cemented lens, and the third lens group (G3) is composed of, from the object side to the image side, a tenth lens (10) with positive focal power, an eleventh lens (11) with positive focal power, a twelfth lens (12) with negative focal power, a seventh lens (7) with negative focal power, an eighth lens (8) with positive focal power and a ninth lens (9) with negative focal power. The thirteenth lens (13) and the fourteenth lens (14) with positive focal power are composed, the eleventh lens (11) and the twelfth lens (12) are combined into a cemented lens, the fourth lens group (G4) is composed of a fifteenth lens (15) with negative focal power, a sixteenth lens (16) with positive focal power, a seventeenth lens (17) with negative focal power, and an eighteenth lens (18) with positive focal power in order from the object side, the seventeenth lens (17) and the eighteenth lens (18) are combined into a cemented lens, and the conditional formula is satisfied: Nd6>1.85; Nd9>1.85; Nd15>1.85; Nd16>1.85 Nd12-Nd13<0.3 Wherein, Nd6, Nd9, Nd12, Nd13, Nd15, and Nd16 are respectively the refractive indices of the sixth lens (6), the ninth lens (9), the twelfth lens (12), the thirteenth lens (13), the fifteenth lens (15), and the sixteenth lens (16); The fifth lens group (G5) is composed of a nineteenth lens (19) with positive optical power.

2. The spherical high-magnification lens according to claim 1, characterized in that: Satisfy the conditions: 3<ft1 / f1<4 -4<f001 / ft<-2.5 Wherein, ft1 is the focal length of the first lens group (G1) at the telephoto end, f1 is the focal length of the first lens group, f001 is the focal length of the first lens (1), and ft is the focal length of the entire system at the telephoto end.

3. The spherical high-magnification lens according to claim 1, characterized in that: Satisfy the conditions: 1.5<f006 / f2<3 18<fw / L1-2<22 4.5<(ft-fw) / Lt-w<5.5 Among them, f006 is the focal length of the sixth lens (6), f2 is the focal length of the second lens group (G2), fw is the focal length of the entire system at the wide-angle end, ft is the focal length of the entire system at the telephoto end, L1-2 is the distance between the first lens group (G2) and the second lens group (G2) at the wide-angle end, and Lt-w is the moving distance of the lens group of the entire system from the wide-angle end to the telephoto end.

4. The spherical high-magnification lens according to claim 1, characterized in that: Satisfy the conditions: 2.5<f010 / fw<4 2.5<fw / f3<4 3.5<ft / L1-3<4.5 Wherein, f010 is the focal length of the tenth lens (10), fw is the focal length of the entire system at the wide-angle end, f3 is the focal length of the third lens group (G3), ft is the focal length of the entire system at the telephoto end, and L1-3 is the distance from the first lens group (G1) to the third lens group (G3).

5. The spherical high-magnification lens according to claim 1, characterized in that: Satisfy the conditions: 3.8<(ft4-fw4) / f4<5.2 1.4<f4 / f3<2 Among them, ft4 is the focal length of the fourth lens group (G4) at the telephoto end, fw4 is the focal length of the fourth lens group (G4) at the wide-angle end, f4 is the focal length of the fourth lens group (G4), and f3 is the focal length of the third lens group (G3).

6. The spherical high-magnification lens according to claim 1, characterized in that: Satisfy the conditions: 0.1<fw5 / f5<0.3 Among them, fw5 is the focal length of the fifth lens group (G5) at the wide-angle end, and f5 is the focal length of the fifth lens group (G5).

7. The spherical high-magnification lens according to claim 1, characterized in that: The nineteenth lens (19) is a lens made of ultra-low dispersion glass.

Images