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CN-117826387-B - Zoom lens and imaging device

CN117826387BCN 117826387 BCN117826387 BCN 117826387BCN-117826387-B

Abstract

The invention relates to the field of optics, in particular to a zoom lens and an imaging device. The zoom lens sequentially comprises a first fixed lens group with positive focal power, a variable 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 third fixed lens group with positive focal power from the object plane side to the image plane side, wherein the second fixed lens group comprises two groups of cemented lenses, the third fixed lens group at least comprises one lens with positive focal power, and the zoom lens meets the following conditions that ft/fw is 20, TTL is less than 100mm, 2 is less than fg5/fw is less than 3. By limiting the focal length of the third fixed lens group and limiting the inner lens, the third fixed lens group can well correct chromatic aberration and aberration of the front group, and imaging quality of the zoom lens is improved.

Inventors

  • YUAN DUO
  • CHEN SANZHONG
  • WANG YAN
  • WANG LIQIN

Assignees

  • 嘉兴中润光学科技股份有限公司

Dates

Publication Date
20260505
Application Date
20231130

Claims (7)

  1. 1. The zoom lens is characterized by comprising a first fixed lens group with positive focal power, a zoom 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 third fixed lens group with positive focal power in sequence from an object plane side to an image plane side; The zoom lens group and the focusing lens group move along the main optical axis direction of the zoom lens; The first fixed lens group consists of a first fixed lens with negative focal power, a second fixed lens with positive focal power, a third fixed lens with positive focal power and a fourth fixed lens with positive focal power in sequence from the object plane side to the image plane side, and the first fixed lens and the second fixed lens are glued; the zoom lens group comprises a first zoom lens with negative focal power, a second zoom lens with negative focal power, a third zoom lens with positive focal power and a fourth zoom lens with negative focal power in sequence from an object plane side to an image plane side; The second fixed lens group comprises a fifth fixed lens with positive focal power, a sixth fixed lens with negative focal power, a seventh fixed lens with positive focal power, an eighth fixed lens with negative focal power and a ninth fixed lens with positive focal power in sequence from the object plane side to the image plane side, wherein the sixth fixed lens and the seventh fixed lens form a double-cemented lens, and the eighth fixed lens and the ninth fixed lens form the double-cemented lens; The focusing lens group comprises a first focusing lens with positive focal power and a second focusing lens with negative focal power in sequence from the object plane side to the image plane side, and the first focusing lens and the second focusing lens are glued; The second fixed lens group comprises two groups of cemented lenses; The third fixed lens group at least comprises a lens with positive focal power; the third fixed lens group is formed by a tenth fixed lens with negative focal power and an eleventh fixed lens with positive focal power in sequence from the object plane side to the image plane side, and the tenth fixed lens and the eleventh fixed lens are glued together; The zoom lens satisfies the following conditional expression: ft/fw>20; TTL<100mm; 2<fG5/fw<3; wherein ft is a focal length of the zoom lens in a telephoto state, fw is a focal length of the zoom lens in a wide-angle state, TTL is an optical total length of the zoom lens, and fG5 is a focal length of the third fixed lens group.
  2. 2. A zoom lens according to claim 1, wherein: and an aspheric lens is arranged in each of the variable magnification lens group and the second fixed lens group.
  3. 3. A zoom lens according to claim 1, wherein: The zoom lens satisfies the following conditional expression: 0.3<XG2/TTL<0.35; Wherein XG2 is the moving distance of the variable magnification lens group.
  4. 4. A zoom lens according to claim 1, wherein: The zoom lens satisfies the following conditional expression: 0.1<XG4/XG2<0.2; wherein XG4 is the moving distance of the focusing lens group.
  5. 5. A zoom lens according to claim 1, wherein: the eleventh fixed lens satisfies the following conditional expression: 0.9<R112/(R111+R112)<1.2; wherein R111 is a radius of curvature of the surface of the eleventh fixed lens near the object plane, and R112 is a radius of curvature of the surface of the eleventh fixed lens near the image plane.
  6. 6. A zoom lens according to claim 1, wherein: two groups of cemented lenses in the second fixed lens group respectively meet one of the following conditional expressions: 4<f1/fw<8; 30<f2/fw<35; Wherein f1 and f2 are focal lengths of the two groups of cemented lenses in the second fixed lens group respectively.
  7. 7. An image forming apparatus, comprising: the zoom lens according to any one of claims 1 to 6; And an imaging element configured to receive an image formed by the zoom lens.

Description

Zoom lens and imaging device Technical Field The invention relates to the field of optics, in particular to a zoom lens and an imaging device. Background The zoom lens is a camera lens capable of changing focal length within a certain range so as to obtain images with different sizes and different scenery ranges. The zoom lens can change the photographing range by varying the focal length without changing the photographing distance, and thus is very advantageous for picture composition. Because a zoom lens can play the role of a plurality of fixed focus lenses, the quantity of photographic equipment carried is reduced and the time for changing the lenses is saved when the user travels. The existing zoom lens is generally large in size in the use process, miniaturization of the zoom lens is an overall trend of the current lens industry, and for the zoom lens with large magnification and miniaturization, the problem of low imaging quality exists in the zoom lens. Disclosure of Invention The invention solves the prior technical problems, and provides a zoom lens and an imaging device, which reduce the number of lenses in the zoom lens and the cost of the zoom lens by arranging a plurality of groups of double-cemented lenses, and simultaneously, the zoom lens is miniaturized, and meanwhile, the third fixed lens group can well correct chromatic aberration and aberration of the front group and increase the imaging quality of the zoom lens by limiting the focal length of the third fixed lens group and limiting the inner lens. The technical scheme provided by the invention is as follows: A zoom lens, which sequentially comprises a first fixed lens group with positive focal power, a zoom 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 third fixed lens group with positive focal power from an object plane side to an image plane side; The zoom lens group and the focusing lens group move along the main optical axis direction of the zoom lens; The first fixed lens group consists of a first fixed lens with negative focal power, a second fixed lens with positive focal power, a third fixed lens with positive focal power and a fourth fixed lens with positive focal power in sequence from the object plane side to the image plane side, and the first fixed lens and the second fixed lens are glued; the zoom lens group comprises a first zoom lens with negative focal power, a second zoom lens with negative focal power, a third zoom lens with positive focal power and a fourth zoom lens with negative focal power in sequence from an object plane side to an image plane side; The focusing lens group comprises a first focusing lens with positive focal power and a second focusing lens with negative focal power in sequence from the object plane side to the image plane side, and the first focusing lens and the second focusing lens are glued; The second fixed lens group comprises two groups of cemented lenses; The third fixed lens group at least comprises a lens with positive focal power; The zoom lens satisfies the following conditional expression: ft/fw>20; TTL<100mm; 2<fG5/fw<3; wherein ft is a focal length of the zoom lens in a telephoto state, fw is a focal length of the zoom lens in a wide-angle state, TTL is an optical total length of the zoom lens, and fG5 is a focal length of the third fixed lens group. In the technical scheme, through the definition of the structure and the parameters, the number of lenses in the zoom lens is reduced by the arrangement of a plurality of groups of double-cemented lenses, the cost of the zoom lens is reduced, the miniaturization of the zoom lens is realized, and meanwhile, through the definition of the focal length of the third fixed lens group and the definition of the inner lens, the chromatic aberration and the aberration of the front group can be well corrected by the third fixed lens group, and the imaging quality of the zoom lens is improved. Preferably, the second fixed lens group is composed of a fifth fixed lens with positive focal power, a sixth fixed lens with negative focal power, a seventh fixed lens with positive focal power, an eighth fixed lens with negative focal power, and a ninth fixed lens with positive focal power in sequence from the object plane side to the image plane side, the sixth fixed lens and the seventh fixed lens form a double-cemented lens, and the eighth fixed lens and the ninth fixed lens form the double-cemented lens. Preferably, the third fixed lens group is composed of a tenth fixed lens of negative power and an eleventh fixed lens of positive power in this order from the object plane side to the image plane side, and the tenth fixed lens and the eleventh fixed lens are cemented. Preferably, the third fixed lens group is composed of a tenth fixed lens of positive power and an eleventh fixed lens of positive power in this order from the object plane side to the image p