CN105842829A - Zoom lens - Google Patents

Abstract

A zoom lens includes a first lens group and a second lens group arranged in sequence from the magnification side to the reduction side. The first lens group has negative refractive power and includes a first lens, a second lens, a third lens and a fourth lens arranged in order from the magnification side to the reduction side, and the first lens, the second lens, the third lens and the fourth lens are arranged in order from the magnification side to the reduction side. The refractive powers of the four lenses are negative, negative, negative and positive. The second lens group has positive refractive power and includes a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens arranged in order from the magnification side to the reduction side, and the fifth lens, the sixth lens, the ninth lens The refractive powers of the seventh lens, the eighth lens and the ninth lens are positive, negative, positive, negative and positive in order.

Description

zoom lens

This application is a divisional application of the invention patent application with application number 201310728265.9. The filing date of the original application is December 26, 2013, and the name of the invention is "zoom lens".

technical field

The present invention relates to an optical lens, and in particular to a zoom lens.

Background technique

With the advancement of optoelectronic technology, image sensing devices (such as cameras, video cameras, etc.) have been widely used in various fields of daily life, or in factory production lines, to replace what human eyes or humans can do. In this way, human beings can have more time and manpower to do more important things. On the other hand, the use of image sensing devices can also allow people to notice places that are not easily noticed by human eyes, or to achieve effective monitoring effects in the absence of people.

In the image sensing device, in addition to the quality of the image sensor (such as a charge coupled device (CCD) or a complementary metal oxide semiconductor sensor (CMOS sensor), etc.) In addition to having a decisive impact on the image quality received, the quality of the optical lens is also the key. Therefore, how to properly design a lens to achieve good image quality has always been the focus of lens designers.

Zoom lenses are proposed in US Patent Nos. 5,155,629, 5,329,402, 7,933,075, 7,557,839, 6,839,183, 7,944,620, 7,184,220, 6,917,477, and 6,809,882. In addition, US Patent No. 7075719 proposes a projection lens.

Contents of the invention

The invention provides a zoom lens, which has the advantages of small size, wide viewing angle, high resolution, large aperture, good infrared correction and the like.

Other purposes and advantages of the present invention can be further understood from the technical features disclosed in the present invention.

To achieve one or part or all of the above objectives or other objectives, an embodiment of the present invention provides a zoom lens configured between the zoom-in side and the zoom-out side. The zoom lens includes a first lens group and a second lens group. The first lens group is disposed between the enlargement side and the reduction side, and has negative refractive power. The first lens group includes a first lens, a second lens, a third lens and a fourth lens arranged in sequence from the magnification side to the reduction side, and the diopters of the first lens, the second lens, the third lens and the fourth lens are in order Negative, negative, negative and positive. The second lens group is disposed between the first lens group and the reduction side, and has positive refractive brightness. The second lens group includes a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens arranged in sequence from the magnifying side to the reducing side, and the fifth lens, the sixth lens, the seventh lens, and the eighth lens And the refractive power of the ninth lens is positive, negative, positive, negative and positive in sequence. The zoom lens complies with -2.8<f1/fw<-2.3 and 0.6<∣f1/f2∣<0.9, where f1 is the effective focal length (EFL) of the first lens group, and f2 is the effective focal length of the second lens group , and fw is the effective focal length of the zoom lens at the wide-angle end.

Based on the above, since the zoom lens of the embodiment of the present invention has a lens combination whose diopter is negative, negative, negative, positive, positive, negative, positive, negative, and positive from the zoom-in side to the zoom-out side, and conforms to -2.8<f1 /fw<-2.3 and 0.6<∣f1/f2∣<0.9, so the zoom lens in the embodiment of the present invention has both wide viewing angle and good imaging quality.

Description of drawings

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail with reference to the accompanying drawings.

1A to 1C are structural schematic diagrams of a zoom lens at a wide-angle end, a middle position, and a telephoto end, respectively, according to an embodiment of the present invention.

2A to 2C are optical simulation data diagrams of the zoom lens in FIG. 1A at the wide-angle end.

3A to 3C are optical simulation data diagrams when the zoom lens of FIG. 1B is at a middle position.

4A to 4C are optical simulation data diagrams of the zoom lens in FIG. 1C at the telephoto end.

5A to 5C are structural schematic diagrams of a zoom lens at a wide-angle end, a middle position, and a telephoto end, respectively, according to another embodiment of the present invention.

6A to 6C are optical simulation data diagrams of the zoom lens in FIG. 5A at the wide-angle end.

7A to 7C are optical simulation data diagrams when the zoom lens of FIG. 5B is in the middle position.

8A to 8C are optical simulation data diagrams of the zoom lens in FIG. 5C at the telephoto end.

detailed description

The aforementioned and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the drawings. The directional terms mentioned in the following embodiments, such as: up, down, left, right, front or back, etc., are only referring to the directions of the drawings. Accordingly, the directional terms are used to illustrate and not to limit the invention.

1A to 1C are structural schematic diagrams of a zoom lens at a wide-angle end, a middle position, and a telephoto end, respectively, according to an embodiment of the present invention. Please refer to FIG. 1A to FIG. 1C , the zoom lens 100 of this embodiment is configured between the zoom-in side and the zoom-out side. The zoom lens 100 includes a first lens group 110 and a second lens group 120 . The first lens group 110 is disposed between the enlargement side and the reduction side, and has negative diopter brightness. The first lens group 110 includes a first lens 111, a second lens 112, a third lens 113, and a fourth lens 114 arranged in order from the zoom side to the zoom side, and the first lens 111, the second lens 112, and the third lens 113 And the refractive power of the fourth lens 114 is negative, negative, negative and positive in sequence. The second lens group 120 is disposed between the first lens group 110 and the reduction side, and has positive refractive brightness. The second lens group 120 includes a fifth lens 121, a sixth lens 122, a seventh lens 123, an eighth lens 124, and a ninth lens 125 arranged in order from the magnification side to the reduction side, and the fifth lens 121, the sixth lens 122 The diopters of the seventh lens 123, the eighth lens 124 and the ninth lens 125 are positive, negative, positive, negative and positive in sequence.

In this embodiment, the zoom lens 100 complies with -2.8<f1/fw<-2.3 and 0.6<∣f1/f2|<0.9, where f1 is the effective focal length of the first lens group 110, and f2 is the effective focal length of the second lens group 120 effective focal length, and fw is the effective focal length of the zoom lens 100 at the wide-angle end.

In this embodiment, the first lens 111, the second lens 112, the third lens 113 and the fourth lens 114 are spherical lenses (spherical lens), and the fifth lens 121, the sixth lens 122, the seventh lens 123, At least two of the eighth lens 124 and the ninth lens 125 are aspheric lenses. Specifically, in this embodiment, the fifth lens 121 is, for example, an aspheric lens, and the ninth lens 125 is, for example, an aspheric lens, and the sixth lens 122, the seventh lens 123, and the eighth lens 124 are, for example, spherical lenses. .

In this embodiment, the zoom lens 100 further includes an aperture stop 130 disposed between the first lens group 110 and the second lens group 120 . In this embodiment, the second lens group 120 is a zoom group, and the first lens group 110 is a focus group. In addition, in this embodiment, when the zoom lens 100 changes from the wide-angle end to the telephoto end, the position of the aperture stop 130 remains unchanged relative to the reduction side, and the first lens group 110 and the second lens group 120 move toward the aperture. The aperture 130 approaches, for example, changes from the state of FIG. 1A to the state of FIG. 1B, and then changes to the state of FIG. 1C.

In this embodiment, the third lens 113 and the fourth lens 114 form a double cemented lens 115 , and the sixth lens 122 and the seventh lens 123 form a double cemented lens 126 . In addition, in this embodiment, the first lens 111 is, for example, a convex-concave lens (convex-concave lens) with a convex surface facing the magnification side, the second lens 112 is, for example, a biconcave lens (biconcave lens), and the third lens 113 is, for example, a convex surface facing the magnification side. The fourth lens 114 is, for example, a concave-convex lens (concave-convex lens) with a convex surface facing the magnification side, the fifth lens 121 is, for example, a biconvex lens (biconvex lens), and the sixth lens 122 is, for example, a convex-convex lens with a convex surface facing the magnification side. As for the lenses, the seventh lens 123 is, for example, a biconvex lens, the eighth lens 124 is, for example, a convex-convex lens with a convex surface facing the magnification side, and the ninth lens 125 is, for example, a biconvex lens. In addition, in this embodiment, the image sensor 60 can be configured on the zoom-out side, and the scene on the zoom-in side can be imaged on the image sensor 60 by the zoom lens 100 . The image sensor 60 is, for example, a digital micromirror device or a complementary metal oxide semiconductor sensor device. When the zoom lens 100 zooms, the position of the aperture stop 130 remains unchanged relative to the position of the image sensor 60 .

The zoom lens 100 of this embodiment adopts lens combinations whose diopters are negative, negative, negative, positive, positive, negative, positive, negative, and positive from the magnification side to the reduction side. The first lens group 110 and the second lens group 120 The diopters are negative and positive respectively, and both the first lens group 110 and the second lens group 120 move relative to the reduction side (that is, move relative to the aperture stop 130) during zooming, so the zoom lens 100 of this embodiment can achieve Miniaturization, no vignetting and wide viewing angle. For example, the zoom lens 100 of this embodiment can make the field of view (2ω) (field of view, FOV) in the diagonal direction of the image sensor 60 as high as 143.2 degrees. In addition, the zoom lens 100 of this embodiment can achieve a resolution of 3 million pixels. In addition, part of the lenses (for example, the seventh lens 123 ) of the zoom lens 100 of this embodiment can be made of low-dispersion glass material, so as to improve the confocal effect of visible light and infrared light. In other words, the image sensing device using the zoom lens 100 can detect clear images with good focus when detecting visible light images during the day and detecting infrared light images at night. Furthermore, the zoom lens 100 of this embodiment can have a large aperture, and in one embodiment, the f-number of the zoom lens can be as small as 1.4. The zoom lens 100 of this embodiment is suitable for matching with a larger-sized image sensor 60. However, when the zoom lens 100 of this embodiment is matched with a smaller-sized image sensor 60 , it can still provide a good viewing range.

An embodiment of the zoom lens 100 will be described below. It should be noted that the data listed in Table 1, Table 2, and Table 3 below are not intended to limit the present invention, and any person with ordinary knowledge in the technical field may, after referring to the present invention, determine its parameters or The setting is properly changed, but it should still belong to the implementation scope of the present invention.

(Table I)

(Table II)

In Table 1, the distance refers to the linear distance between two adjacent surfaces on the optical axis A. For example, the distance between the surface S1 is the linear distance between the surface S1 and the surface S2 on the optical axis A. For the thickness, refractive index and Abbe number corresponding to each lens in the remarks column, please refer to the values corresponding to each pitch, refractive index and Abbe number in the same column. In addition, in Table 1, surfaces S1 and S2 are the two surfaces of the first lens 111, surfaces S3 and S4 are the two surfaces of the second lens 112, surface S5 is the surface of the third lens 113 facing the magnification side, and surface S6 is the surface of the second lens 113. The surface of the third lens 113 and the fourth lens 114 are connected, and the surface S7 is the surface of the fourth lens 114 facing the reduction side. The surface S8 is the position of the infrared cut filter (infrared cut filter) 70 (such as an infrared cut film), and the surface S9 is the position of the aperture stop 130, wherein the light-transmitting substrate 80 is used to carry the infrared cut filter. In the light device 70 , the surface S8 is the surface of the transparent substrate 80 facing the enlargement side, and the surface S9 is the surface of the transparent substrate 80 facing the reduction side. The surfaces S10 and S11 are the two surfaces of the fifth lens 121, the surface S12 is the surface of the sixth lens 122 facing the magnification side, the surface S13 is the surface connecting the sixth lens 122 and the seventh lens 123, and the surface S14 is the seventh lens 123 The surface facing the reduced side. The surfaces S15 and S16 are two surfaces of the eighth lens 124 , and the surfaces S17 and S18 are two surfaces of the ninth lens 125 . A cover glass 50 may be provided between the surface S18 and the image sensor 60 to protect the image sensor 60 . The distance filled in the row of the surface S18 is the distance from the surface S18 to the image sensor 60 .

In addition, Table 2 lists the effective focal length, aperture (F/#), field of view, and variable distances d1, d2, and d3 of the zoom lens 100 at the wide-angle end, middle position, and telephoto end.

The above-mentioned surfaces S10, S11, S17 and S18 are even-order aspheric surfaces, which can be expressed by the following formula:

$\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; cr</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; c</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 6</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 6</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 8</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}^{\mathrm{<span\; class="notranslate">\; 10</span>}}$

In the formula, Z is the offset (sag) in the direction of the optical axis A, and c is the reciprocal of the radius of the osculating sphere, that is, the radius of curvature near the optical axis A (such as S10, S11, S17 in Table 1 and the reciprocal of the radius of curvature of S18). k is the quadric surface coefficient (conic), r is the height of the aspheric surface, that is, the height from the center of the lens to the edge of the lens, and A2, A4, A6, A8 and A10 are the aspheric coefficients (aspheric coefficient), in this embodiment The coefficient A2 is 0. Table 3 below lists the aspheric parameter values of surfaces S10, S11, S17 and S18.

(Table 3)

2A to 2C are optical simulation data diagrams of the zoom lens of FIG. 1A at the wide-angle end, FIGS. 3A to 3C are optical simulation data diagrams of the zoom lens of FIG. 1B at the middle position, and FIGS. 4A to 4C are diagrams The optical simulation data diagram of the 1C zoom lens at the telephoto end. Please refer to Fig. 2A to Fig. 4C, wherein Fig. 2A, Fig. 3A and Fig. 4A are simulated data diagrams of longitudinal aberration (longitudinal aberration) simulated at a wavelength of 588 nm, wherein the pupil radius (pupilradius) of Fig. 2A is 1.0135 mm, the pupil radius of Figure 3A is 1.4449 mm, and the pupil radius of Figure 4A is 1.5338 mm (that is, in Figure 2A, Figure 3A and Figure 4A, the maximum scale of the vertical axis (the scale at the top) is 1.0135 mm, 1.4449 mm and 1.5338 mm). Fig. 2B, Fig. 3B and Fig. 4B are optical simulation data diagrams of field curvature and distortion (distortion) based on a wavelength of 588 nanometers, wherein the maximum field angle (half angle) of Fig. 2B is 71.588 degrees, and Fig. The maximum viewing angle (half angle) of 3B is 37.952 degrees, while the maximum viewing angle (half angle) of FIG. 4B is 25.835 degrees. In addition, in the graph of curvature of field, S represents data in the sagittal direction, and T represents data in the tangential direction. Fig. 2C, Fig. 3C and Fig. 4C are the optical simulation data diagrams of lateral chromatic aberration simulated at wavelengths of 486, 588 and 656 nanometers, wherein Fig. 2C, Fig. 3C and Fig. height) are 3.41 mm. The graphs shown in FIGS. 2A to 4C are all within the standard range, so it can be verified that the zoom lens 100 of this embodiment can indeed have good optical imaging quality.

5A to 5C are structural schematic diagrams of a zoom lens at a wide-angle end, a middle position, and a telephoto end, respectively, according to another embodiment of the present invention. Please refer to FIG. 5A to FIG. 5C , the zoom lens 100 a of this embodiment is similar to the zoom lens 100 in FIG. 1A to FIG. 1C , and the main differences between the two are as follows. Referring to FIGS. 5A to 5C , in the second lens group 120a of the zoom lens 100a of the present embodiment, the eighth lens 124a is a biconcave lens, and the ninth lens 125a is a meniscus lens with a convex surface facing the magnification side. The zoom lens 100a of this embodiment can also achieve the advantages and functions of the above-mentioned zoom lens 100, which will not be repeated here.

An embodiment of the zoom lens 100a will be described below. It should be noted that the data listed in the following Table 4, Table 5 and Table 6 are not intended to limit the present invention, and any person with ordinary knowledge in the technical field may, after referring to the present invention, determine its parameters or Appropriate changes may be made to the settings, but they still fall within the scope of the present invention.

(Table 4)

(Table 5)

The physical meaning of each parameter in Table 4 can refer to the description of Table 1, and will not be repeated here. In addition, Table 5 lists the effective focal length, aperture (F/#), field of view, and variable distances d1, d2, and d3 of the zoom lens 100a at the wide-angle end, middle position, and telephoto end.

The aforementioned surfaces S10 , S11 , S17 and S18 are even-order aspheric surfaces, and their formulas are the same as those applicable in Table 3 above. The coefficient A2 is 0 in this embodiment. Table 6 below lists the aspheric parameter values of the surfaces S10 , S11 , S17 and S18 of the zoom lens 100 a.

(Table 6)

6A to 6C are optical simulation data diagrams of the zoom lens of FIG. 5A at the wide-angle end, FIGS. 7A to 7C are optical simulation data diagrams of the zoom lens of FIG. 5B at the middle position, and FIGS. 8A to 8C are diagrams The optical simulation data diagram of the 5C zoom lens at the telephoto end. Please refer to Fig. 6A to Fig. 8C, wherein Fig. 6A, Fig. 7A and Fig. 8A are the simulated data diagrams of longitudinal aberration simulated at a wavelength of 588 nanometers, wherein the pupil radius of Fig. 6A is 1.0033 mm, and the pupil radius of Fig. 7A The radius is 1.4024 mm, and the pupil radius of Figure 8A is 1.4714 mm (that is, in Figure 6A, Figure 7A and Figure 8A, the maximum scale of the vertical axis (the scale at the top) is 1.0033 mm, 1.4024 mm and 1.4714 mm respectively ). Fig. 6B, Fig. 7B and Fig. 8B are optical simulation data diagrams of field curvature and distortion based on a wavelength of 588 nanometers, wherein the maximum viewing angle (half angle) of Fig. 6B is 71.761 degrees, and the maximum viewing angle of Fig. 7B (half angle) is 38.324 degrees, while the maximum viewing angle (half angle) of FIG. 8B is 25.908 degrees. In addition, in the graph of field curvature, S represents the data of the sagittal direction, and T represents the data of the meridian direction. Fig. 6C, Fig. 7C and Fig. 8C are the optical simulation data diagrams of lateral chromatic aberration simulated at wavelengths of 486, 588 and 656 nanometers, wherein the maximum image heights of Fig. 6C, Fig. 7C and Fig. height) are 3.41 mm. The graphs shown in FIGS. 6A to 8C are all within the standard range, so it can be verified that the zoom lens 100 a of this embodiment can indeed have good optical imaging quality.

To sum up, since the zoom lens of the embodiment of the present invention has a lens combination whose diopter is negative, negative, negative, positive, positive, negative, positive, negative, and positive from the zoom-in side to the zoom-out side, and conforms to -2.8 <f1/fw<-2.3 and 0.6<|f1/f2|<0.9, so the zoom lens of the embodiment of the present invention has both a wide viewing angle and good imaging quality.

The above descriptions are only preferred embodiments of the present invention, and cannot limit the scope of the present invention. All simple equivalent changes and modifications made according to the claims of the present invention and the content of the description of the invention still belong to the patent of the present invention. within the scope covered. In addition, any embodiment or claim of the present invention does not need to achieve all the objects or advantages or features disclosed in the present invention. In addition, the abstract and the title are only used to assist in the search of patent documents, and are not used to limit the scope of rights of the present invention.

Symbol Description

50: glass cover

60: Image sensor

70: Infrared light cut filter

80: Transparent substrate

100, 100a: zoom lens

110: The first lens group

111: first lens

112: second lens

113: third lens

114: fourth lens

115, 126: doublet lens

120, 120a: the second lens group

121: fifth lens

122: sixth lens

123: seventh lens

124, 124a: Eighth lens

125, 125a: ninth lens

130: Aperture stop

A: optical axis

S1～S18: surface.

Claims (12)

1. A zoom lens configured to be disposed between an enlargement side and a reduction side, the zoom lens comprising a first lens group and a second lens group, The first lens group is arranged between the enlargement side and the reduction side, and has negative diopter brightness, and the first lens group includes four lenses; The second lens group is arranged between the first lens group and the reduction side, and has positive refractive brightness, and the second lens group includes five lenses; Wherein, the zoom lens complies with -2.8<f1/fw<-2.3 and 0.6<∣f1/f2|<0.9, wherein f1 is the effective focal length of the first lens group, f2 is the effective focal length of the second lens group, and fw is the effective focal length of the zoom lens at the wide-angle end. 2. The zoom lens according to claim 1, wherein the first lens group comprises a first lens, a second lens, a third lens, and a first lens arranged in sequence from the zoom side to the zoom side. Four lenses, the first lens, the second lens, the third lens and the fourth lens are all spherical lenses. 3. The zoom lens as claimed in claim 2, wherein the third lens and the fourth lens form a doublet lens. 4. The zoom lens as claimed in claim 1, wherein the second lens group comprises a fifth lens, a sixth lens, a seventh lens, and a first lens arranged in sequence from the enlargement side to the reduction side. Eight lenses and a ninth lens, at least two of the second lens group are aspherical lenses. 5. The zoom lens as claimed in claim 4, wherein the sixth lens and the seventh lens form a doublet lens. 6. The zoom lens as claimed in claim 4, wherein the fifth lens or the ninth lens is an aspheric lens. 7. The zoom lens as claimed in claim 1, further comprising an aperture stop disposed between the first lens group and the second lens group. 8. The zoom lens according to claim 7, wherein when the zoom lens changes from the wide-angle end to the telephoto end, the position of the aperture stop remains unchanged relative to the narrowing side, and the first lens The group and the second lens group are close to the aperture stop. 9. The zoom lens as claimed in claim 1, wherein the second lens group is a zoom group, and the first lens group is a focus group. 10. The zoom lens according to claim 1, wherein the first lens group comprises a first lens, a second lens, a third lens, and a first lens arranged in sequence from the zoom-in side to the zoom-out side. Four lenses, the second lens group includes a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens arranged in sequence from the magnification side to the reduction side, the first lens is A convex-convex lens with a convex surface facing the magnifying side, the second lens is a biconcave lens, the third lens is a convex-concave lens with a convex surface facing the magnifying side, the fourth lens is a concave-convex lens with a convex surface facing the magnifying side, and the fifth lens is A biconvex lens, the sixth lens is a convex-concave lens with a convex surface facing the magnification side, the seventh lens is a biconvex lens, the eighth lens is a convex-convex lens with a convex surface facing the magnification side, or the ninth lens is a biconvex lens. 11. The zoom lens according to claim 1, wherein the first lens group comprises a first lens, a second lens, a third lens, and a first lens arranged in sequence from the zoom-in side to the zoom-out side. Four lenses, the second lens group includes a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens arranged in sequence from the magnification side to the reduction side, the first lens is A convex-convex lens with a convex surface facing the magnifying side, the second lens is a biconcave lens, the third lens is a convex-concave lens with a convex surface facing the magnifying side, the fourth lens is a concave-convex lens with a convex surface facing the magnifying side, and the fifth lens is A biconvex lens, the sixth lens is a convex-convex lens with a convex surface facing the magnification side, the seventh lens is a biconvex lens, the eighth lens is a bi-concave lens, or the ninth lens is a concave-convex lens with a convex surface facing the magnification side. 12. The zoom lens as claimed in claim 1, wherein the first lens group comprises a first lens arranged in sequence from the zoom-in side to the zoom-out side and whose diopters are negative, negative, negative, and positive in sequence, A second lens, a third lens and a fourth lens, the second lens group includes a fifth lens arranged in sequence from the magnification side to the reduction side and whose diopter is positive, negative, positive, negative and positive in sequence , a sixth lens, a seventh lens, an eighth lens and a ninth lens.