Zoom lens and imaging device

Abstract

The present application relates to the field of optics, specifically to a zoom lens and an imaging device. The zoom lens sequentially comprises, from the object side to the image side, a first fixed lens group with positive focal power, a first variable magnification lens group with negative focal power, a second fixed lens group with positive focal power, a focusing lens group with negative focal power, and a second variable magnification lens group with positive focal power. The zoom lens satisfies the following conditional expressions: fnow < 2; fnot < 3.5; ft / fw > 7.5; wherein fnow is the aperture number of the zoom lens in the wide-angle state, fnot is the aperture number of the zoom lens in the telephoto state, fw is the focal length of the zoom lens in the wide-angle state, and ft is the focal length of the zoom lens in the telephoto state. The zoom lens can achieve a small aperture number in both the wide-angle state and the telephoto state, realize a large aperture of the zoom lens, and enhance the night vision effect of the zoom lens.

Description

Technical Field

[0001] This invention relates to the field of optics, specifically to a zoom lens and an imaging device. Background Technology

[0002] A zoom lens is a lens that can change its focal length within a certain range to obtain different widths of field of view, different sizes of images, and different ranges of objects. A zoom lens can change the shooting range by changing the focal length without changing the shooting distance, which is very beneficial for image composition.

[0003] With the increasing popularity of zoom lenses, they are playing an important role in more and more fields such as surveillance and video conferencing. However, current zoom lenses mainly use glass lenses, which are increasingly unable to meet the growing demand for low cost, low weight, and high image quality in surveillance lenses.

[0004] Currently, small zoom lenses typically have a larger front aperture and a smaller rear aperture, making them unsuitable for applications with smaller apertures. Summary of the Invention

[0005] This invention addresses existing technical problems by providing a zoom lens and imaging device. The zoom lens can achieve a small aperture number in both wide-angle and telephoto modes, thus achieving a large aperture and enhancing the night vision effect of the zoom lens.

[0006] The technical solution provided by this invention is as follows:

[0007] A zoom lens, wherein the zoom lens is composed of, from the object plane side to the image plane side, a first fixed lens group with positive optical power, a first zoom lens group with negative optical power, a second fixed lens group with positive optical power, a focusing lens group with negative optical power, and a second zoom lens group with positive optical power.

[0008] The zoom lens satisfies the following condition:

[0009] fnow < 2;

[0010] fnot < 3.5;

[0011] ft / fw > 7.5;

[0012] Wherein, fnow is the aperture number of the zoom lens in wide-angle mode, fnot is the aperture number of the zoom lens in telephoto mode, fw is the focal length of the zoom lens in wide-angle mode, and ft is the focal length of the zoom lens in telephoto mode.

[0013] In this technical solution, by limiting the above parameters, a medium magnification zoom lens is achieved. The zoom lens can achieve a small aperture in both wide-angle and telephoto modes, thus achieving a large aperture and enhancing the night vision effect of the zoom lens.

[0014] Preferably, the first fixed lens group consists of a first fixed lens with negative optical power, a second fixed lens with positive optical power, a third fixed lens with positive optical power, and a fourth fixed lens with positive optical power, arranged sequentially from the object plane side to the image plane side, with the first fixed lens and the second fixed lens cemented together.

[0015] Preferably, the first zoom lens group consists of a first zoom lens with negative optical power, a second zoom lens with negative optical power, a third zoom lens with negative optical power, and a fourth zoom lens with positive optical power, arranged sequentially from the object plane side to the image plane side, with the third zoom lens and the fourth zoom lens cemented together.

[0016] Preferably, the second fixed lens group includes, from the object plane side to the image plane side, the following components in sequence:

[0017] A fifth fixed lens with positive optical power, a sixth fixed lens with positive optical power, a seventh fixed lens with negative optical power, and an eighth fixed lens with positive optical power, together with the sixth, seventh, and eighth fixed lenses, form a cemented triplet lens.

[0018] Preferably, the focusing lens group is formed by cementing a first focusing lens with negative optical power and a second focusing lens with positive optical power, or the focusing lens group is a first focusing lens with negative optical power.

[0019] and / or

[0020] The second zoom lens group consists of a fifth zoom lens with positive optical power.

[0021] Preferably, the zoom lens comprises at most one aspherical lens.

[0022] In this technical solution, the cost of zoom lenses is reduced by minimizing the use of aspherical lenses. At the same time, the use of aspherical lenses can also improve the coma and aberrations of zoom lenses to a certain extent, thereby increasing the image quality of zoom lenses.

[0023] Preferably, the lenses in the second zoom lens group are aspherical lenses.

[0024] In this technical solution, the use of aspherical lenses can be minimized by the above-mentioned structure, and the correction effect of aspherical lenses on image quality can be increased.

[0025] Preferably, the zoom lens satisfies the following condition:

[0026] Db1 / fw > 0.45;

[0027] Wherein, Db1 is the length of the first zoom lens on the principal optical axis.

[0028] In this technical solution, by setting a thicker first zoom lens, the zoom capability of the first zoom lens is increased, and the number of lenses inside the zoom lens is reduced.

[0029] Preferably, the zoom lens satisfies the following condition:

[0030] (Db1-Cb1) / fw < 0.04;

[0031] Wherein, Cb1 is the thickness of the edge of the first zoom lens.

[0032] In this technical solution, by limiting the thickness of the edge of the first zoom lens, the effects of excessive aberrations and coma caused by excessive thickness of the first zoom lens are reduced, thereby increasing the imaging quality of the zoom lens.

[0033] Preferably, the zoom lens satisfies the following condition:

[0034] 2<|(Rb11+Rb12) / (Rb11-Rb12)|<4;

[0035] Wherein, Rb11 is the radius of curvature of the surface of the first zoom lens near the object plane, and Rb12 is the radius of curvature of the surface of the first zoom lens near the image plane.

[0036] In this technical solution, by limiting the above parameters, the difference in the radius of curvature of the two curved surfaces of the first zoom lens is further reduced, the possibility of abrupt changes in the optical path after the light passes through the first zoom lens is reduced, and the reliability of the zoom lens zoom is increased.

[0037] Preferably, the zoom lens satisfies the following condition:

[0038] Db5 / fw > 0.4;

[0039] Wherein, Db5 is the length of the fifth zoom lens on the principal optical axis.

[0040] In this technical solution, by limiting the thickness of the fifth zoom lens, the number of lenses in the second zoom lens group is reduced, thereby achieving miniaturization of the zoom lens.

[0041] Preferably, the zoom lens satisfies the following condition:

[0042] 1 < SG2 / fw < 2;

[0043] Wherein, SG2 is the moving distance of the first zoom lens group.

[0044] In this technical solution, by limiting the above parameters, the first zoom group has a suitable moving distance, the zoom lens has a large zoom range, and at the same time, it will not cause a large size, thus realizing the miniaturization of the zoom lens.

[0045] Preferably, the zoom lens satisfies the following condition:

[0046] SG4 / SG2 < 0.5;

[0047] Wherein, SG4 is the moving distance of the focusing lens group.

[0048] In this technical solution, by limiting the moving distance of the focusing lens group, the focusing accuracy of the focusing lens group is increased, thereby increasing the imaging quality of the zoom lens.

[0049] Preferably, the zoom lens satisfies the following condition:

[0050] SG5 / SG2 < 0.8;

[0051] Wherein, SG5 is the moving distance of the second zoom lens group.

[0052] In this technical solution, by limiting the moving distance of the second zoom lens group, the coma and aberrations of the image are further reduced with minimal impact on the size of the zoom lens, thereby increasing the image quality of the zoom lens.

[0053] Preferably, the zoom lens satisfies the following condition:

[0054] 0.35 < DOI / TTL < 0.45;

[0055] Wherein, DOI is the distance between the aperture and the image plane.

[0056] In this technical solution, by limiting the above parameters, the second fixed lens group, the focusing lens group, and the second zoom lens group can better correct coma and aberration in imaging, thereby increasing the imaging quality of the zoom lens.

[0057] One of the objectives of this invention is to provide an imaging device, comprising: a zoom lens; and an imaging element configured to receive an image formed by the zoom lens.

[0058] Compared with the prior art, the zoom lens and imaging device provided by the present invention have the following beneficial effects:

[0059] 1. By limiting the parameters mentioned above, a medium magnification zoom lens is achieved. The zoom lens can achieve a small aperture in both wide-angle and telephoto modes, thus achieving a larger aperture and enhancing the night vision effect of the zoom lens.

[0060] 2. By reducing the use of aspherical lenses, the cost of zoom lenses is reduced. At the same time, the use of aspherical lenses can also improve the coma and aberrations of zoom lenses to a certain extent, thereby increasing the image quality of zoom lenses.

[0061] 3. By limiting the thickness of the edge of the first zoom lens, the effects of excessive aberrations and coma caused by excessive thickness of the first zoom lens are reduced, thereby increasing the imaging quality of the zoom lens. Attached Figure Description

[0062] The preferred embodiments will now be described in a clear and easy-to-understand manner, with reference to the accompanying drawings, to further explain the above-mentioned characteristics, technical features, advantages, and implementation methods of a zoom lens and imaging device.

[0063] Figure 1 This is a schematic diagram of the structure of a zoom lens according to the present invention;

[0064] Figure 2 This is an aberration diagram of a zoom lens in telephoto mode according to the present invention;

[0065] Figure 3 This invention provides a coma diagram of a zoom lens in telephoto mode.

[0066] Figure 4 This is an aberration diagram of a zoom lens in a wide-angle state according to the present invention;

[0067] Figure 5 This invention relates to a coma diagram of a zoom lens in a wide-angle state.

[0068] Figure 6 This is a schematic diagram of another zoom lens according to the present invention;

[0069] Figure 7 This is another aberration diagram of the zoom lens in telephoto mode according to the present invention;

[0070] Figure 8 This is another coma diagram of the zoom lens in telephoto mode according to the present invention;

[0071] Figure 9 This is another aberration diagram of the zoom lens in the wide-angle state according to the present invention;

[0072] Figure 10 This is another coma diagram of the zoom lens in the wide-angle state according to the present invention.

[0073] Explanation of reference numerals: G1, First fixed lens group; G2, First zoom lens group; G3, Second fixed lens group; G4, Focusing lens group; G5, Second zoom lens group; G6, Auxiliary component; a1, First fixed lens; a2, Second fixed lens; a3, Third fixed lens; a4, Fourth fixed lens; a5, Fifth fixed lens; a6, Sixth fixed lens; a7, Seventh fixed lens; a8, Eighth fixed lens; b1, First zoom lens; b2, Second zoom lens; b3, Third zoom lens; b4, Fourth zoom lens; b5, Fifth zoom lens; c1, First focusing lens; c2, Second focusing lens; STO, Aperture stop; CG1, First protective glass; CG2, Second protective glass. Detailed Implementation

[0074] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0075] To keep the drawings concise, each figure only schematically shows the parts relevant to the invention, and these do not represent the actual structure of the product. Furthermore, to facilitate understanding, in some figures, only one of components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0076] Example 1

[0077] like Figure 1 and Figure 6 As shown, a zoom lens, comprising, from the object plane side to the image plane side, the following components:

[0078] The first fixed lens group G1 with positive optical power, the first zoom lens group G2 with negative optical power, the aperture STO, the second fixed lens group G3 with positive optical power, the focusing lens group G4 with negative optical power, and the second zoom lens group G5 with positive optical power.

[0079] The zoom lens satisfies the following condition:

[0080] fnow < 2;

[0081] fnot < 3.5;

[0082] ft / fw > 7.5;

[0083] Wherein, fnow is the aperture number of the zoom lens in wide-angle mode, fnot is the aperture number of the zoom lens in telephoto mode, fw is the focal length of the zoom lens in wide-angle mode, and ft is the focal length of the zoom lens in telephoto mode.

[0084] In this embodiment, by limiting the above parameters, the zoom lens with medium magnification is limited. The zoom lens can achieve a small aperture in both wide-angle and telephoto modes, thus achieving a large aperture and enhancing the night vision effect of the zoom lens.

[0085] The first fixed lens group G1 includes, from the object plane side to the image plane side, the following:

[0086] A first fixed lens a1 with negative optical power, a second fixed lens a2 with positive optical power, a third fixed lens a3 with positive optical power, a fourth fixed lens a4 with positive optical power, and the first fixed lens a1 and the second fixed lens a2 are cemented together.

[0087] The first zoom lens group G2, from the object plane side to the image plane side, includes the following:

[0088] A first zoom lens b1 with negative optical power, a second zoom lens b2 with negative optical power, a third zoom lens b3 with negative optical power, and a fourth zoom lens b4 with positive optical power, the third zoom lens b3 and the fourth zoom lens b4 are cemented together.

[0089] The second fixed lens group G3 includes, from the object plane side to the image plane side, the following:

[0090] The fifth fixed lens a5 with positive optical power, the sixth fixed lens a6 with positive optical power, the seventh fixed lens a7 with negative optical power, and the eighth fixed lens a8 with positive optical power, together form a cemented three-layer lens.

[0091] The focusing lens group G4 is formed by cementing together a first focusing lens c1 with negative optical power and a second focusing lens c2 with positive optical power, or the focusing lens group G4 is a first focusing lens c1 with negative optical power.

[0092] and / or

[0093] The second zoom lens group G5 is a fifth zoom lens b5 with positive optical power.

[0094] The zoom lens contains at most one aspherical lens.

[0095] In this embodiment, by reducing the use of aspherical lenses, the cost of the zoom lens is reduced. At the same time, the use of aspherical lenses can also improve the coma and aberrations of the zoom lens to a certain extent, thereby increasing the image quality of the zoom lens.

[0096] The lenses in the second zoom lens group G5 are aspherical lenses.

[0097] By designing the above structure, the use of aspherical lenses can be minimized, while the correction effect of aspherical lenses on image quality can be increased.

[0098] The zoom lens satisfies the following condition:

[0099] Db1 / fw > 0.45;

[0100] Wherein, Db1 is the length of the first zoom lens b1 on the principal optical axis.

[0101] In this embodiment, by setting a thicker first zoom lens b1, the zoom capability of the first zoom lens b1 is increased, and the number of lenses inside the zoom lens is reduced.

[0102] The zoom lens satisfies the following condition:

[0103] (Db1-Cb1) / fw < 0.04;

[0104] Wherein, Cb1 is the thickness of the edge of the first zoom lens b1.

[0105] By limiting the thickness of the edge of the first zoom lens b1, the effects of excessive aberrations and coma caused by excessive thickness of the first zoom lens b1 are reduced, thereby increasing the imaging quality of the zoom lens.

[0106] The zoom lens satisfies the following condition:

[0107] 2<|(Rb11+Rb12) / (Rb11-Rb12)|<4;

[0108] Wherein, Rb11 is the radius of curvature of the surface of the first zoom lens b1 near the object plane, and Rb12 is the radius of curvature of the surface of the first zoom lens b1 near the image plane.

[0109] By limiting the parameters mentioned above, the difference in the radius of curvature of the two curved surfaces on both sides of the first zoom lens b1 is further reduced, which reduces the possibility of abrupt changes in the optical path after the light passes through the first zoom lens b1 and increases the reliability of the zoom lens's magnification.

[0110] The zoom lens satisfies the following condition:

[0111] Db5 / fw > 0.4;

[0112] Wherein, Db5 is the length of the fifth zoom lens b5 on the principal optical axis.

[0113] In this embodiment, by limiting the thickness of the fifth zoom lens b5, the number of lenses in the second zoom lens group G5 is reduced, thereby achieving miniaturization of the zoom lens.

[0114] The zoom lens satisfies the following condition:

[0115] 1 < SG2 / fw < 2;

[0116] Wherein, SG2 is the moving distance of the first zoom lens group G2.

[0117] With the above parameters in place, the first zoom group has a suitable moving distance, the zoom lens has a large zoom range, and at the same time, it does not result in a large size, thus enabling the miniaturization of the zoom lens.

[0118] The zoom lens satisfies the following condition:

[0119] SG4 / SG2 < 0.5;

[0120] Wherein, SG4 is the moving distance of the focusing lens group G4.

[0121] By limiting the moving distance of the G4 focusing lens group, the focusing accuracy of the G4 focusing lens group is increased, thereby increasing the image quality of the zoom lens.

[0122] The zoom lens satisfies the following condition:

[0123] SG5 / SG2 < 0.8;

[0124] Wherein, SG5 is the moving distance of the second zoom lens group G5.

[0125] In this embodiment, by limiting the moving distance of the second zoom lens group G5, the coma and aberrations of the image are further reduced with minimal impact on the size of the zoom lens, thereby increasing the image quality of the zoom lens.

[0126] The zoom lens satisfies the following condition:

[0127] 0.35 < DOI / TTL < 0.45;

[0128] Wherein, DOI is the distance between the aperture stop STO and the image plane.

[0129] In this embodiment, by limiting the parameters described above, the second fixed lens group G3, the focusing lens group G4, and the second zoom lens group G5 can better correct coma and aberrations in imaging, thereby increasing the imaging quality of the zoom lens.

[0130] Example 2

[0131] like Figures 1 to 5As shown, a zoom lens, comprising, from the object plane side to the image plane side, the following components:

[0132] The first fixed lens group G1 with positive optical power, the first zoom lens group G2 with negative optical power, the aperture stop STO, the second fixed lens group G3 with positive optical power, the focusing lens group G4 with negative optical power, the second zoom lens group G5 with positive optical power, and the auxiliary component G6.

[0133] The first fixed lens group G1 includes, from the object plane side to the image plane side, the following:

[0134] A first fixed lens a1 with negative optical power, a second fixed lens a2 with positive optical power, a third fixed lens a3 with positive optical power, a fourth fixed lens a4 with positive optical power, and the first fixed lens a1 and the second fixed lens a2 are cemented together.

[0135] The first zoom lens group G2, from the object plane side to the image plane side, includes the following:

[0136] A first zoom lens b1 with negative optical power, a second zoom lens b2 with negative optical power, a third zoom lens b3 with negative optical power, and a fourth zoom lens b4 with positive optical power, the third zoom lens b3 and the fourth zoom lens b4 are cemented together.

[0137] The second fixed lens group G3 includes, from the object plane side to the image plane side, the following:

[0138] The fifth fixed lens a5 with positive optical power, the sixth fixed lens a6 with positive optical power, the seventh fixed lens a7 with negative optical power, and the eighth fixed lens a8 with positive optical power, together form a cemented three-layer lens.

[0139] The focusing lens group G4 is cemented together from a first focusing lens c1 with negative optical power and a second focusing lens c2 with positive optical power.

[0140] The second zoom lens group G5 is a fifth zoom lens b5 with positive optical power.

[0141] The auxiliary component G6 includes, from the object plane side to the image plane side, the following components in sequence: a first protective glass CG1 and a second protective glass CG2.

[0142] The basic lens data of the zoom lens in this embodiment is shown in Table 1, the variable parameters in Table 1 are shown in Table 2, and the aspherical coefficients are shown in Table 3.

[0143] The surface number column shows the surface number when the object-side surface is set as surface 1 and the numbering is increased sequentially towards the image side; the surface type column shows the surface type of a lens; the radius of curvature column shows the radius of curvature of a lens, where a positive radius of curvature indicates that the surface is curved towards the object side and a negative radius of curvature indicates that the surface is curved towards the image side; the center thickness column shows the surface spacing on the optical axis between each surface and the surface adjacent to it on the image side; the refractive index column shows the refractive index of a lens; and the Abbe number column shows the Abbe number of a lens.

[0144] In Table 2, the WIDE column indicates the specific values ​​of each variable parameter when the zoom lens is in wide-angle mode, and the TELE column indicates the specific values ​​of each variable parameter when the zoom lens is in telephoto mode.

[0145] In Table 3, K is the conic coefficient and e is the scientific notation, for example, e-005 means 10⁻⁵.

[0146] Table 1

[0147]

[0148]

[0149] Table 2

[0150] D1 1.40 36.71 D2 36.62 1.310 D3 1.17 11.79 D4 9.67 21.30 D5 24.69 2.44

[0151] Table 3

[0152]

[0153] In this embodiment, fnow = 1.85, fnot = 3.85, TTL = 144.98mm, fw = 21.2mm, ft = 176.9mm, and ft / fw = 8.34;

[0154] Wherein, fnow is the aperture number of the zoom lens in wide-angle mode, fnot is the aperture number of the zoom lens in telephoto mode, fw is the focal length of the zoom lens in wide-angle mode, ft is the focal length of the zoom lens in telephoto mode, and TTL is the total optical length of the zoom lens.

[0155] Db1 = 10 mm, DB1 / fw = 0.47;

[0156] Wherein, Db1 is the length of the first zoom lens b1 on the principal optical axis.

[0157] Cb1=9.55mm, (Db1-Cb1) / fw=0.021;

[0158] Wherein, Cb1 is the thickness of the edge of the first zoom lens b1.

[0159] Rb11=33.47mm, Rb12=16.66mm;

[0160] |(Rb11+Rb12) / (Rb11-Rb12)|=2.98;

[0161] Wherein, Rb11 is the radius of curvature of the surface of the first zoom lens b1 near the object plane, and Rb12 is the radius of curvature of the surface of the first zoom lens b1 near the image plane.

[0162] Db5=9.57mm, Db5 / fw=0.45;

[0163] Wherein, Db5 is the length of the fifth zoom lens b5 on the principal optical axis.

[0164] SG2=35.31mm, SG2 / fw=1.67;

[0165] SG4=10.62mm, SG4 / SG2=0.3;

[0166] SG5=22.25mm, SG5 / SG2=0.63;

[0167] Wherein, SG2 is the moving distance of the first zoom lens group G2, SG4 is the moving distance of the focusing lens group G4, and SG5 is the moving distance of the second zoom lens group G5.

[0168] Db5Imin=5.49mm;

[0169] Wherein, Db5Imin is the minimum distance between the fifth zoom lens and the image plane.

[0170] DOI=67.54mm, DOI / TTL=0.38;

[0171] Wherein, DOI is the distance between the aperture stop STO and the image plane.

[0172] Example 3

[0173] like Figures 6 to 10 As shown, a zoom lens, comprising, from the object plane side to the image plane side, the following components:

[0174] The first fixed lens group G1 with positive optical power, the first zoom lens group G2 with negative optical power, the aperture stop STO, the second fixed lens group G3 with positive optical power, the focusing lens group G4 with negative optical power, the second zoom lens group G5 with positive optical power, and the auxiliary component G6.

[0175] The first fixed lens group G1 includes, from the object plane side to the image plane side, the following:

[0176] A first fixed lens a1 with negative optical power, a second fixed lens a2 with positive optical power, a third fixed lens a3 with positive optical power, a fourth fixed lens a4 with positive optical power, and the first fixed lens a1 and the second fixed lens a2 are cemented together.

[0177] The first zoom lens group G2, from the object plane side to the image plane side, includes the following:

[0178] A first zoom lens b1 with negative optical power, a second zoom lens b2 with negative optical power, a third zoom lens b3 with negative optical power, and a fourth zoom lens b4 with positive optical power, the third zoom lens b3 and the fourth zoom lens b4 are cemented together.

[0179] The second fixed lens group G3 includes, from the object plane side to the image plane side, the following:

[0180] The fifth fixed lens a5 with positive optical power, the sixth fixed lens a6 with positive optical power, the seventh fixed lens a7 with negative optical power, and the eighth fixed lens a8 with positive optical power, together form a cemented three-layer lens.

[0181] The focusing lens group G4 is a first focusing lens c1 with negative optical power.

[0182] The second zoom lens group G5 is a fifth zoom lens b5 with positive optical power.

[0183] The auxiliary component G6 includes, from the object plane side to the image plane side, the following components in sequence: a first protective glass CG1 and a second protective glass CG2.

[0184] The basic lens data of the zoom lens in this embodiment is shown in Table 4, the variable parameters in Table 4 are shown in Table 5, and the aspherical coefficients are shown in Table 6.

[0185] The surface number column shows the surface number when the object-side surface is set as surface 1 and the numbering is increased sequentially towards the image side; the surface type column shows the surface type of a lens; the radius of curvature column shows the radius of curvature of a lens, where a positive radius of curvature indicates that the surface is curved towards the object side and a negative radius of curvature indicates that the surface is curved towards the image side; the center thickness column shows the surface spacing on the optical axis between each surface and the surface adjacent to it on the image side; the refractive index column shows the refractive index of a lens; and the Abbe number column shows the Abbe number of a lens.

[0186] In Table 5, the WIDE column indicates the specific values ​​of each variable parameter when the zoom lens is in the wide-angle position, and the TELE column indicates the specific values ​​of each variable parameter when the zoom lens is in the telephoto position.

[0187] In Table 6, K is the conic coefficient and e is the scientific notation, for example, e-005 means 10⁻⁵.

[0188] Table 4

[0189]

[0190]

[0191] Table 5

[0192] D1 4.60 36.73 D2 33.18 1.05 D3 0.10 12.31 D4 12.44 21.09 D5 23.69 2.83

[0193] Table 6

[0194]

[0195] In this embodiment, fnow = 1.85, fnot = 3.78, TTL = 145mm, fw = 20.4mm, ft = 183.6mm, and ft / fw = 9;

[0196] Wherein, fnow is the aperture number of the zoom lens in wide-angle mode, fnot is the aperture number of the zoom lens in telephoto mode, fw is the focal length of the zoom lens in wide-angle mode, ft is the focal length of the zoom lens in telephoto mode, and TTL is the total optical length of the zoom lens.

[0197] Db1 = 10 mm, DB1 / fw = 0.49;

[0198] Wherein, Db1 is the length of the first zoom lens b1 on the principal optical axis.

[0199] Cb1=9.23mm, (Db1-Cb1) / fw=0.038;

[0200] Wherein, Cb1 is the thickness of the edge of the first zoom lens b1.

[0201] Rb11=33.32mm, Rb12=16.39mm;

[0202] |(Rb11+Rb12) / (Rb11-Rb12)|=2.94;

[0203] Wherein, Rb11 is the radius of curvature of the surface of the first zoom lens b1 near the object plane, and Rb12 is the radius of curvature of the surface of the first zoom lens b1 near the image plane.

[0204] Db5=9.02mm, Db5 / fw=0.44;

[0205] Wherein, Db5 is the length of the fifth zoom lens b5 on the principal optical axis.

[0206] SG2=32.13mm, SG2 / fw=1.58;

[0207] SG4=12.21mm, SG4 / SG2=0.38;

[0208] SG5=20.87mm, SG5 / SG2=0.65;

[0209] Wherein, SG2 is the moving distance of the first zoom lens group G2, SG4 is the moving distance of the focusing lens group G4, and SG5 is the moving distance of the second zoom lens group G5.

[0210] DOI=63.7mm, DOI / TTL=0.439;

[0211] Wherein, DOI is the distance between the aperture stop STO and the image plane.

[0212] Example 5

[0213] like Figures 1 to 10 As shown, an imaging device includes: a zoom lens as described in any of the above embodiments, and an imaging element configured to receive an image formed by the zoom lens.

[0214] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A zoom lens, characterized in that, The zoom lens consists of, from the object plane side to the image plane side, a first fixed lens group with positive optical power, a first zoom lens group with negative optical power, an aperture stop, a second fixed lens group with positive optical power, a focusing lens group with negative optical power, and a second zoom lens group with positive optical power. The first fixed lens group consists of a first fixed lens with negative optical power, a second fixed lens with positive optical power, a third fixed lens with positive optical power, and a fourth fixed lens with positive optical power, arranged sequentially from the object plane side to the image plane side. The first fixed lens and the second fixed lens are cemented together. The first zoom lens group consists of a first zoom lens with negative optical power, a second zoom lens with negative optical power, a third zoom lens with negative optical power, and a fourth zoom lens with positive optical power, arranged sequentially from the object plane side to the image plane side. The third zoom lens and the fourth zoom lens are cemented together. The second fixed lens group consists of a fifth fixed lens with positive optical power, a sixth fixed lens with positive optical power, a seventh fixed lens with negative optical power, and an eighth fixed lens with positive optical power, from the object plane side to the image plane side. The sixth fixed lens, the seventh fixed lens, and the eighth fixed lens form a three-crystal lens. The focusing lens group is composed of a first focusing lens with negative optical power and a second focusing lens with positive optical power cemented together, or the focusing lens group is a first focusing lens with negative optical power. The second zoom lens group consists of a fifth zoom lens with positive optical power; The zoom lens satisfies the following condition: fnow < 2; fnot < 3.5; ft / fw > 7.5; Wherein, fnow is the aperture number of the zoom lens in wide-angle mode, fnot is the aperture number of the zoom lens in telephoto mode, fw is the focal length of the zoom lens in wide-angle mode, and ft is the focal length of the zoom lens in telephoto mode.

2. A zoom lens according to claim 1, characterized in that: The zoom lens contains at most one aspherical lens.

3. A zoom lens according to claim 1 or 2, characterized in that: The lenses in the second zoom lens group are aspherical lenses.

4. A zoom lens according to claim 1, characterized in that: The zoom lens satisfies the following condition: Db1 / fw > 0.45; Wherein, Db1 is the length of the first zoom lens on the principal optical axis.

5. A zoom lens according to claim 4, characterized in that: The zoom lens satisfies the following condition: (Db1-Cb1) / fw < 0.04; Wherein, Cb1 is the thickness of the edge of the first zoom lens.

6. A zoom lens according to claim 1, characterized in that: The zoom lens satisfies the following condition: 2<|(Rb11+Rb12) / (Rb11-Rb12)|<4; Wherein, Rb11 is the radius of curvature of the surface of the first zoom lens near the object plane, and Rb12 is the radius of curvature of the surface of the first zoom lens near the image plane.

7. A zoom lens according to claim 1, characterized in that: The zoom lens satisfies the following condition: Db5 / fw > 0.4; Wherein, Db5 is the length of the fifth zoom lens on the principal optical axis.

8. A zoom lens according to claim 1, characterized in that: The zoom lens satisfies the following condition: 1 < SG2 / fw < 2; Wherein, SG2 is the moving distance of the first zoom lens group.

9. A zoom lens according to claim 1, characterized in that: The zoom lens satisfies the following condition: SG4 / SG2 < 0.5; Wherein, SG4 is the moving distance of the focusing lens group.

10. A zoom lens according to claim 1, characterized in that: The zoom lens satisfies the following condition: SG5 / SG2 < 0.8; Wherein, SG5 is the moving distance of the second zoom lens group.

11. A zoom lens according to claim 1, characterized in that: The zoom lens satisfies the following condition: 0.35 < DOI / TTL < 0.45; Wherein, DOI is the distance between the aperture stop and the image plane, and TTL is the total optical length of the zoom lens.

12. An imaging device, characterized in that, include: The zoom lens as described in any one of claims 1 to 11; And an imaging element, configured to receive an image formed by the zoom lens.

Images