Auto focus lens

Abstract

The application discloses an automatic focusing lens, which comprises, in sequence from an object side to an imaging surface, a first lens with positive focal power, wherein the object side of the first lens is a convex surface; a second lens with positive focal power, wherein the object side of the second lens is a convex surface; a third lens with negative focal power, wherein the image side of the third lens is a concave surface; a voltage-driven zoom lens, wherein the voltage-driven zoom lens is provided with a diaphragm; a fourth lens with negative focal power, wherein the image side of the fourth lens is a concave surface; and a fifth lens with positive focal power, wherein the object side and the image side of the fifth lens are both convex surfaces. The automatic focusing lens adopts a combination of five conventional lenses and one voltage-driven zoom lens, which reduces the overall size of the lens, and has the advantages of high imaging quality, fast automatic focusing speed and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of imaging lens, in particular to an automatic focusing lens. BACKGROUND

[0002] Since 2010, China has achieved explosive growth in the field of machine vision, and with the development of camera technology, the camera module has gradually developed from the initial focal system with limited camera conditions to the zoom system capable of switching between different camera conditions.

[0003] The existing zoom system generally changes the distance between lenses by driving part of the lens to move relatively through the voice coil motor to change the focal length of the zoom system, so as to realize the function of automatic focusing in various different shooting distances, and thus to adapt to different object distances, depth of field, shooting range and other camera requirements while ensuring a certain imaging quality. At the same time, in order to obtain higher quality images, the existing zoom system gradually uses higher and higher pixel CCD or CMOS photosensitive chips.

[0004] However, in order to match the high pixels of the photosensitive chip with the image quality of the zoom system, it is usually necessary to increase the number of lenses, which increases the weight and volume of the lens; at the same time, for high-speed applications or precision applications that require rapid refocusing, the existing zoom system is difficult to capture sharp and accurate images, that is, the focusing speed is slow and the image quality is not high. SUMMARY

[0005] Therefore, the purpose of the present application is to provide an automatic focusing lens with high imaging quality and fast automatic focusing speed.

[0006] To achieve the above-mentioned purpose of the application, the technical solution of the present application is as follows:

[0007] The present application provides an automatic focusing lens, which comprises, in order from the object side to the imaging surface: a first lens with positive refractive power, whose object side is convex and whose image side is concave or convex; a second lens with positive refractive power, whose object side is convex and whose image side is convex or concave; a third lens with negative refractive power, whose object side is concave or convex and whose image side is concave; a voltage-driven zoom lens with a diaphragm inside; a fourth lens with negative refractive power, whose object side is concave or convex and whose image side is concave; a fifth lens with positive refractive power, whose object side and image side are both convex; wherein the working object distance of the automatic focusing lens satisfies: 100mm

[0008] Compared with the prior art, the automatic focusing lens provided by the application adopts five lenses with specific optical power and surface type, and a voltage-driven zoom lens with fast automatic focusing speed is matched between the third lens and the fourth lens, so that high-quality imaging can be realized at different working object distances, and the use requirements of application scenarios with relatively high real-time requirements can be well met. BRIEF DESCRIPTION OF DRAWINGS

[0009] The above and / or additional aspects and advantages of the application will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

[0010] Figure 1 A structure schematic diagram of an automatic focusing lens provided by a first embodiment of the application is shown in FIG. 1.

[0011] Figure 2 An F-Theta distortion curve diagram of the automatic focusing lens provided by the first embodiment of the application is shown in FIG. 2.

[0012] Figure 3 An MTF diagram of the automatic focusing lens provided by the first embodiment of the application is shown in FIG. 3.

[0013] Figure 4 A sagittal chromatic aberration diagram of the automatic focusing lens provided by the first embodiment of the application is shown in FIG. 4.

[0014] Figure 5 A structure schematic diagram of an automatic focusing lens provided by a second embodiment of the application is shown in FIG. 5.

[0015] Figure 6 An F-Theta distortion curve diagram of the automatic focusing lens provided by the second embodiment of the application is shown in FIG. 6.

[0016] Figure 7 An MTF diagram of the automatic focusing lens provided by the second embodiment of the application is shown in FIG. 7.

[0017] Figure 8 A sagittal chromatic aberration diagram of the automatic focusing lens provided by the second embodiment of the application is shown in FIG. 8.

[0018] Figure 9 A structure schematic diagram of an automatic focusing lens provided by a third embodiment of the application is shown in FIG. 9.

[0019] Figure 10 An F-Theta distortion curve diagram of the automatic focusing lens provided by the third embodiment of the application is shown in FIG. 10.

[0020] Figure 11 An MTF diagram of the automatic focusing lens provided by the third embodiment of the application is shown in FIG. 11.

[0021] Figure 12 A sagittal chromatic aberration diagram of the automatic focusing lens provided by the third embodiment of the application is shown in FIG. 12. DETAILED DESCRIPTION

[0022] In order to make the objects, features and advantages of the present application more apparent, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. The present application is shown in several embodiments in the drawings. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided for the purpose of making the disclosure of the present application more thorough and comprehensive.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. Throughout this document, the same reference numerals refer to the same elements.

[0024] The automatic focusing lens provided by the embodiments of the present application comprises, from the object side to the imaging surface, a first lens, a second lens, a third lens, a voltage-driven zoom lens, a fourth lens, a fifth lens and a filter, and the optical centers of the lenses are located on the same straight line.

[0025] Specifically, the first lens has positive refractive power, the object side thereof is convex, and the image side thereof is concave or convex; the second lens has positive refractive power, the object side thereof is convex, and the image side thereof is concave or convex; the third lens has negative refractive power, the object side thereof is convex or concave, and the image side thereof is concave; the voltage-driven zoom lens is provided with a diaphragm; the fourth lens has negative refractive power, the object side thereof is convex or concave, and the image side thereof is concave; and the fifth lens has positive refractive power, and the object side and the image side thereof are both convex.

[0026] The automatic focusing lens provided by the embodiments of the present application adopts a reasonable combination of five lenses of conventional materials and one voltage-driven zoom lens, and the surface shape and refractive power of each lens are reasonably designed, so that the lens can achieve the purposes of fast focusing and clear imaging. Specifically, when the automatic focusing lens is working, a starting voltage is applied to the voltage-driven zoom lens, the voltage-driven zoom lens has a corresponding focal length due to the application of the starting voltage, at this time, the voltage-driven zoom lens is in an initial state, and the lens is also in the working distance of the best object distance, so the resolution quality of the lens is in the best state; when the working object distance of the lens changes within the preset working range, the voltage applied to the voltage-driven zoom lens will also be adjusted accordingly, so that the focal length of the voltage-driven zoom lens also changes accordingly, so that the focal length of the voltage-driven zoom lens can be quickly adjusted by adjusting the driving voltage according to the different working object distances of the lens, and the focal length of the entire optical system is changed, so that the optical system can quickly focus and high-definition image under different working object distances.

[0027] In some embodiments, the auto-focusing lens satisfies the following conditional expressions:

[0028] 100mm < OBJ < 200mm; (1)

[0029] 14.4mm < f < 16.4mm; (2)

[0030] 2.48 < f / IH < 2.99; (3)

[0031] wherein OBJ represents the working object distance of the auto-focusing lens, f represents the focal length of the auto-focusing lens, and IH represents the image height of the auto-focusing lens. By satisfying the above conditional expressions (1) to (3), the focal length of the voltage-driven zoom lens can be quickly adjusted by adjusting the input voltage on the voltage-driven zoom lens, so that the focal length of the entire optical system can be quickly adjusted, and the lens can clearly image within the working object distance of 100mm to 200mm while having a larger imaging surface.

[0032] In some embodiments, the auto-focusing lens satisfies the following conditional expressions:

[0033] 1.68 mm / V < OBJ / U < 5.90 mm / V; (4)

[0034] 30V < U < 60V; (5)

[0035] wherein OBJ represents the working object distance of the auto-focusing lens, and U represents the input voltage of the auto-focusing lens in the working state. By satisfying the above conditional expressions (4) and (5), the focal length of the voltage-driven zoom lens can be changed by changing the input voltage on the voltage-driven zoom lens, and then the focal length of the entire optical system can be changed to meet the imaging requirements under different working object distances, i.e., the lens can have good image quality under different working object distances; at the same time, when the voltage-driven zoom lens works between the above lowest voltage and highest voltage, the focal length of the voltage-driven zoom lens can be quickly adjusted to enable the lens to quickly focus.

[0036] In some embodiments, the auto-focusing lens satisfies the following conditional expressions:

[0037] 1.73mm < Nd1 < 1.93mm; (6)

[0038] 1.70mm < Nd2 < 1.90mm; (7)

[0039] 1.75mm < Nd3 < 1.85mm; (8)

[0040] wherein, Nd1 represents the refractive index of the first lens, Nd2 represents the refractive index of the second lens, and Nd3 represents the refractive index of the third lens. The refractive index reflects the refractive ability of the lens to light. In general, the higher the refractive index, the stronger the refractive ability. By selecting a lens material with a higher refractive index to meet the above condition formulas (6) to (8), the first lens, the second lens and the third lens can bear part of the optical power of the optical system, which helps to correct the aberration of the optical system and improve the resolving power. At the same time, the convergence ability of the light can be strengthened, and better image quality can be obtained within a near object distance (100mm < OBJ < 200mm).

[0041] In some embodiments, the autofocus lens satisfies the following condition formula:

[0042] 2 mm < CT34 < 6 mm; (9)

[0043] wherein, CT34 represents the air gap between the third lens and the fourth lens on the optical axis. By reasonably controlling the air gap between the third lens and the fourth lens to meet the above condition formula (9), the resolving power of the lens can be ensured while meeting the lens installation requirements. When the value of CT34 exceeds the upper limit, the gap between the third lens and the fourth lens will be too large, which is not conducive to the voltage-driven zoom lens to present the shooting picture on the imaging surface after adjusting the focal length, resulting in a decrease in the resolution of the lens and low image quality. When the value of CT34 exceeds the lower limit, there is not enough gap between the third lens and the fourth lens to install the voltage-driven zoom lens, which makes it difficult to assemble the lens.

[0044] In some embodiments, the autofocus lens satisfies the following condition formula:

[0045] 0.87 < FOV / TTL < 1.15; (10)

[0046] wherein, FOV represents the maximum field of view of the autofocus lens, and TTL represents the total optical length of the autofocus lens. By reasonably controlling the ratio of the maximum field of view to the total optical length of the autofocus lens to meet the above condition formula (10), the total optical length of the lens can be reasonably shortened, which is conducive to reducing the weight and volume of the lens and is conducive to correcting the aberration to improve the imaging quality of the lens.

[0047] In some embodiments, the autofocus lens satisfies the following condition formula:

[0048] 0.64 < FNO / IH < 0.72; (11)

[0049] FNO*IH≥0.5 (11)

[0050] In some embodiments, the auto-focusing lens satisfies the following conditional expression:

[0051] 0.02 < (CT1-ET1) / (ET1+CT1) < 0.3 (12)

[0052] wherein CT1 represents the center thickness of the first lens, and ET1 represents the edge thickness of the first lens. Satisfying the above conditional expression (12), by reasonably controlling the edge thickness and the center thickness of the first lens, the resolving power of the lens can be ensured while meeting the molding degree of the first lens, and the lens also has certain correction ability for aberrations such as distortion.

[0053] In some embodiments, the auto-focusing lens satisfies the following conditional expression:

[0054] 10 < Vd2-Vd3 < 30 (13)

[0055] wherein Vd2 represents the Abbe number of the second lens, and Vd3 represents the Abbe number of the third lens. The Abbe number is used to represent the index of dispersion ability of a transparent medium. Generally, the smaller the Abbe number of a lens, the more serious the dispersion; on the contrary, the larger the Abbe number of a lens, the less serious the dispersion. Satisfying the above conditional expression (13) can well correct the chromatic aberration of the lens. When the value of Vd2-Vd3 exceeds the lower limit, the chromatic aberration correction of the system will be insufficient; when the value of Vd2-Vd3 exceeds the upper limit, the local chromatic aberration correction will be too large, and material selection will be difficult.

[0056] In some embodiments, the auto-focusing lens satisfies the following conditional expression:

[0057] 0.22 < (CT1+CT2+CT3) / TTL < 0.33 (14)

[0058] wherein TTL represents the total optical length of the auto-focusing lens, CT1 represents the center thickness of the first lens, CT2 represents the center thickness of the second lens, and CT3 represents the center thickness of the third lens. Satisfying the above conditional expression (14), by reasonably controlling the center thicknesses of the first lens, the second lens and the third lens, the lens can have higher image quality at a close object distance.

[0059] In some embodiments, the auto-focusing lens satisfies the following conditional expression:

[0060] 3 < |R7 / R8| < 6; (15)

[0061] 8 x 10 -6 < |f4 x (dn / dt) | < 1.8 x 10 2 < |f4 x (dn / dt) | < 1.8 x 10 -5 ; (16)

[0062] wherein R7 represents a curvature radius of the object side surface of the fourth lens, R8 represents a curvature radius of the image side surface of the fourth lens, f4 represents an effective focal length of the fourth lens, and dn / dt represents a material refractive index temperature coefficient of the fourth lens. The conditions (15) and (16) are satisfied, the surface shape of the fourth lens can be reasonably controlled, the sensitivity of the lens can be reduced, and the high and low temperature performance of the lens can be improved by controlling the relationship between the focal length of the fourth lens and the material refractive index temperature coefficient.

[0063] In some embodiments, the autofocus lens satisfies the following condition:

[0064] 0.5 < f45 / f < 4.0; (17)

[0065] wherein f45 represents a combined focal length of the fourth lens and the fifth lens, and f represents a focal length of the autofocus lens. The condition (17) is satisfied, the focal length of the fourth lens and the fifth lens can be reasonably distributed, the higher-order aberration can be reduced, and the total optical length of the lens can be reduced.

[0066] In some embodiments, the autofocus lens satisfies the following condition:

[0067] 0.1 < IH / TTL < 0.5; (18)

[0068] wherein TTL represents a total optical length of the autofocus lens, and IH represents an image height of the autofocus lens. The condition (18) is satisfied, the total length and volume of the lens can be effectively controlled while the lens has a large imaging surface. When the value of IH / TTL exceeds the lower limit, the total length of the lens is too long, which is difficult to meet the miniaturization requirement, or the target surface is too small when the total length is small enough, which is difficult to match a larger chip.

[0069] In some embodiments, the autofocus lens satisfies the following condition:

[0070] -1.2 < R9 / R10 < -0.2; (19)

[0071] Wherein, R9 represents the curvature radius of the object side surface of the fifth lens, and R10 represents the curvature radius of the image side surface of the fifth lens. The condition formula (19) is satisfied, the shape of the fifth lens can be reasonably controlled, the ghost phenomenon of the lens can be reduced, and the optical performance of the lens is improved.

[0072] In some embodiments, the autofocus lens satisfies the following condition formula:

[0073] 5 < CRA < 13; (20)

[0074] Wherein, CRA represents the incident angle of the chief ray of the autofocus lens on the imaging surface at the maximum field angle. The condition formula (20) is satisfied, the imaging requirement of the conventional large CRA chip in the market can be better matched.

[0075] In some embodiments, the autofocus lens adopts five glass spherical lenses, the volume of the lens can be effectively reduced, and a voltage-driven zoom lens is used for realizing the autofocus of the system, so that the images at different working distances can be clearly collected, the lens can well withstand the fluctuations of temperature, pressure and motion, and has good applicability in high-speed application or precision application fields which require rapid refocusing.

[0076] The application will be further described in the following embodiments. In each embodiment, the thickness, curvature radius and material selection of each lens in the lens are different, and the specific differences can be referred to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the application, but the embodiments of the application are not limited to the following embodiments, and any changes, substitutions, combinations or simplifications made without departing from the innovative points of the application should be regarded as equivalent replacement methods, and are included in the protection scope of the application.

[0077] First embodiment

[0078] Please refer to Figure 1 A structure schematic diagram of an autofocus lens 100 provided by the first embodiment of the application is shown in the figure, the autofocus lens 100 includes, along the optical axis from the object side to the imaging surface S13, a first lens L1, a second lens L2, a third lens L3, a voltage-driven zoom lens, a fourth lens L4, a fifth lens L5 and a filter L6, and the optical centers of the lenses are located on the same straight line.

[0079] Specifically, the first lens L1 has positive refractive power, the object side S1 is a convex surface, and the image side S2 is a concave surface; the second lens L2 has positive refractive power, the object side S3 and the image side S4 are both convex surfaces; the third lens L3 has negative refractive power, the object side S5 and the image side S6 are both concave surfaces; the fourth lens L4 has negative refractive power, the object side S7 and the image side S8 are both concave surfaces; the fifth lens L5 has positive refractive power, the object side S9 and the image side S10 are both convex surfaces; the object side of the filter L6 is S11, and the image side is S12; at the same time, the voltage-driven zoom lens is provided with a diaphragm inside, and the voltage-driven zoom lens can have different radii of curvature inside according to different applied working voltages, so that the voltage-driven zoom lens has different focal lengths. The voltage applied to the voltage-driven zoom lens in the embodiment is in the range of 35V-59V. Specifically, when the voltage-driven zoom lens is in the initial state, the starting voltage applied thereto is 37.7V, at this time, the focal length of the entire autofocus lens is 16mm, and at this time, the resolution quality of the autofocus lens is in the best state; when the working object distance of the autofocus lens changes within the set range such as 100mm-200mm, at this time, the voltage on the voltage-driven zoom lens will be adjusted within the range of 35V-59V, at the same time, the focal length of the entire autofocus lens fluctuates within the range of 14.425mm-16.374mm, and presents a higher resolution.

[0080] Please refer to Table 1, which shows the related parameters of each lens of the autofocus lens 100 in the embodiment.

[0081] Table 1

[0082]

[0083] Please refer to Figure 2 , which shows the F-Theta distortion graph of the autofocus lens 100 provided by the first embodiment of the application. As can be seen from the graph, the F-Theta distortion of the lens is small and less than 2%, which shows that the autofocus lens 100 can effectively correct the distortion.

[0084] Please refer to Figure 3 , which shows the MTF graph of the autofocus lens 100 provided by the first embodiment of the application. As can be seen from the graph, the lens point MTF value is above 0.5 at a spatial frequency of 133lp / mm, which shows that the autofocus lens 100 has a higher point resolution.

[0085] Please refer to Figure 4 , which shows the axial chromatic aberration graph of the autofocus lens 100 provided by the first embodiment of the application. As can be seen from the graph, the offset of the axial chromatic aberration is within ±1μm, which shows that the autofocus lens 100 can effectively correct the axial chromatic aberration.

[0086] Second embodiment

[0087] Referring to Figure 5 , the structural diagram of the auto-focusing lens 200 provided by the second embodiment. The auto-focusing lens 200 in this embodiment is substantially the same as the auto-focusing lens 100 in the first embodiment, and the difference lies in that the relevant parameters of each lens are different from those in the first embodiment; meanwhile, the voltage range applied on the voltage-driven zoom lens in this embodiment is 34V-55V. Specifically, when the voltage-driven zoom lens is in the initial state, the starting voltage applied thereon is 34.3V, at this time, the focal length of the entire auto-focusing lens is 16mm, at this time, the resolution quality of the lens is in the best state; when the working object distance of the auto-focusing lens changes within the set range such as 100mm-200mm, at this time, the voltage on the voltage-driven zoom lens is adjusted within the range of 34V-55V, at the same time, the focal length of the entire auto-focusing lens fluctuates within the range of 14.890mm-16.250mm, and presents a higher resolution.

[0088] Referring to Table 2, the relevant parameters of each lens of the auto-focusing lens 200 in this embodiment are shown.

[0089] Table 2

[0090]

[0091]

[0092] Referring to Figure 6 , the F-Theta distortion diagram of the auto-focusing lens 200 provided by the second embodiment of the present application is shown, from which it can be seen that the F-Theta distortion of the lens is small and less than 2%, which indicates that the auto-focusing lens 200 can effectively correct the distortion.

[0093] Referring to Figure 7 , the MTF diagram of the auto-focusing lens 200 provided by the second embodiment of the present application is shown, from which it can be seen that the point MTF value of the lens is above 0.45 under the spatial frequency of 133lp / mm, which indicates that the auto-focusing lens 200 has a higher point resolution.

[0094] Referring to Figure 8 , the sagittal chromatic aberration diagram of the auto-focusing lens 200 provided by the second embodiment of the present application is shown, from which it can be seen that the offset of the sagittal chromatic aberration is within ±1μm, which indicates that the auto-focusing lens 200 can effectively correct the field curvature.

[0095] Third embodiment

[0096] Referring to Figure 9This is a schematic diagram of the autofocus lens 300 provided in the third embodiment. The autofocus lens 300 in this embodiment is largely the same as the autofocus lens 100 in the first embodiment, except that the relevant parameters of each lens differ from those in the first embodiment. Furthermore, the voltage applied to the voltage-driven zoom lens in this embodiment ranges from 37V to 53V. Specifically, when the voltage-driven zoom lens is in its initial state, the applied starting voltage is 37.9V, and the focal length of the entire lens is 16mm, at which point the lens's resolution is at its best. When the working object distance of the autofocus lens changes within a set range, such as 100mm-200mm, the voltage on the voltage-driven zoom lens is adjusted within the range of 37V-53V, and the focal length of the entire autofocus lens fluctuates within the range of 14.408mm-16.390mm, exhibiting high resolution.

[0097] Please refer to Table 3, which shows the relevant parameters of each lens of the autofocus lens 300 in this embodiment.

[0098] Table 3

[0099]

[0100] Please see Figure 10 The figure shows the F-Theta distortion of the autofocus lens 300 provided in the third embodiment of the present invention. As can be seen from the figure, the F-Theta distortion of the lens is small and less than 2%, indicating that the autofocus lens 300 can effectively correct the distortion.

[0101] Please see Figure 11 The figure shows the MTF diagram of the lens 300 provided in the third embodiment of the present invention. It can be seen from the figure that the lens point MTF value is above 0.5 at a spatial frequency of 133 lp / mm, indicating that the autofocus lens 300 has a high point resolution.

[0102] Please see Figure 12 The figure shows the lateral chromatic aberration diagram of the autofocus lens 300 provided in the third embodiment of the present invention. As can be seen from the figure, the offset of the lateral chromatic aberration is within ±1μm, indicating that the autofocus lens 300 can effectively correct field curvature.

[0103] Please refer to Tables 4 and 5 for the optical characteristics of the autofocus lens provided in each of the three embodiments above, including the focal length f, image height IH, aperture number FNO, and total optical length TTL of the autofocus lens, as well as the relevant values ​​corresponding to each conditional expression in the above-mentioned conditional expressions.

[0104] Table 4

[0105] First embodiment Second embodiment Third embodiment FOV 18.82° 21.8° 17.86° IH (mm) 5.8 6.6 5.5 TTL (mm) 20.9 19.0 20.4 FNO 3.74 4.25 3.94 f1 (mm) 20.07 17.80 20.69 f2 (mm) 9.02 8.29 9.80 f3 (mm) -8.76 -5.75 -9.26 f4 (mm) -6.17 -12.48 -5.71 f5 (mm) 7.41 8.39 6.57

[0106] Table 5

[0107]

[0108]

[0109] Compared with the prior art, the automatic focusing lens provided by the present application has at least the following advantages:

[0110] 1. The present application has a clever structure design, and the total length of the lens is greatly reduced by reasonably matching each lens, thereby improving the applicability and overall volume of the lens.

[0111] 2. The present application adopts a voltage-driven zoom lens, which can reduce the mass of the lens, make the zoom structure simpler, and has the characteristics of fast zoom speed.

[0112] 3. The present application adopts a structure of five glass spherical lenses, thereby improving the applicability of the lens at different temperatures and ensuring that good image quality can be obtained under different temperature conditions.

[0113] The above-described embodiments only express several embodiments of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be pointed out that, for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An auto focus lens, six pieces of lenses in total, characterized in that, In order from the object side to the imaging surface along the optical axis, successively comprises: a first lens with positive refractive power, the object side surface of the first lens is convex; a second lens with positive refractive power, the object side surface of the second lens is convex; a third lens with negative refractive power, the image side surface of the third lens is concave; a voltage-driven zoom lens, the voltage-driven zoom lens is provided with a diaphragm therein; a fourth lens with negative refractive power, the image side surface of the fourth lens is concave; a fifth lens with positive refractive power, both the object side surface and the image side surface of the fifth lens are convex; Wherein, the working object distance of the autofocus lens satisfies: 100mm The autofocus lens satisfies the following conditional expression: 14.4mm 2.48 Wherein, f represents the focal length of the autofocus lens; IH represents the image height of the autofocus lens.

2. The auto focus lens according to claim 1, wherein The autofocus lens satisfies the following conditional expression: 0.1 Wherein, TTL represents the total optical length of the autofocus lens, and IH represents the image height of the autofocus lens.

3. The auto focus lens of claim 1, wherein, The autofocus lens satisfies the following conditional expression: 1.68mm / V 30V Wherein, OBJ represents the working object distance of the autofocus lens, and U represents the input voltage of the autofocus lens in the working state.

4. The auto focus lens of claim 1, wherein, The autofocus lens satisfies the following conditional expression: 1.73 1.70 1.75 Wherein, Nd1 represents the refractive index of the first lens, Nd2 represents the refractive index of the second lens, and Nd3 represents the refractive index of the third lens.

5. The auto focus lens of claim 1, wherein, The autofocus lens satisfies the following conditional expression: 0.87° / mm Wherein, FOV represents the maximum field of view angle of the autofocus lens, and TTL represents the total optical length of the autofocus lens.

6. The auto focus lens of claim 1, wherein, The autofocus lens satisfies the following conditional expression: 0.64 / mm Wherein, FNO represents the aperture number of the autofocus lens, and IH represents the image height of the autofocus lens.

7. The auto focus lens of claim 1, wherein, The autofocus lens satisfies the following conditional expression: 0.02 Wherein, CT1 represents the center thickness of the first lens, and ET1 represents the edge thickness of the first lens.

8. The auto focus lens of claim 1, wherein, The autofocus lens satisfies the following conditional expression: 0.22 Wherein, TTL represents the total optical length of the autofocus lens, CT1 represents the center thickness of the first lens, CT2 represents the center thickness of the second lens, and CT3 represents the center thickness of the third lens.

9. The auto focus lens of claim 1, wherein, The autofocus lens satisfies the following conditional expression: 3 | R7 / R8 | 8 x 10 -6 mm / °C 2 <|f4 x (dn / dt) 2 |<1.8 x 10 -5 mm / °C 2 ; wherein R7 represents a curvature radius of an object side surface of the fourth lens, R8 represents a curvature radius of an image side surface of the fourth lens, f4 represents an effective focal length of the fourth lens, and dn / dt represents a material refractive index temperature coefficient of the fourth lens.

10. The auto focus lens of claim 1, wherein, The auto-focusing lens satisfies the following conditional expression: 0.5 < f45 / f < 4.0; wherein f45 represents a combined focal length of the fourth lens and the fifth lens, and f represents a focal length of the auto-focusing lens.

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