Automatic focusing lens group, camera module and electronic equipment

Abstract

The utility model relates to an automatic focusing lens group, a camera module and electronic equipment. The automatic focusing lens group comprises a first lens with positive focal power, wherein the object side surface and the image side surface of the first lens are convex surfaces; the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; at least part of the fourth variable-focus lens can deform so that the effective focal length can be changed; the fifth lens has negative focal power, and the object side surface and the image side surface of the fifth lens are concave surfaces; the sixth lens has positive focal power, and the object side surface and the image side surface of the sixth lens are convex surfaces; the object side surface and the image side surface of the seventh lens are convex surfaces; the fifth lens and the sixth lens are glued together. The automatic focusing lens group satisfies the following conditions: 0 lt; f5 / f < = 0.5; 0 lt; f6 / f < = 0.5. According to the automatic focusing lens group, the miniaturization design, the good imaging quality and the large-range focusing effect can be considered.

Description

Technical Field

[0001] The present application relates to the technical field of barcode scanners, and particularly to an autofocus lens group, an imaging module and an electronic device. Background Art

[0002] Traditional applications of machine vision optics can significantly improve the flexibility and automation of industrial production and are widely used in industrial production. Among them, as an important industrial imaging device, when the optical system is applied to a barcode scanner, the barcode scanner usually needs to acquire images of objects with different sizes and object distances, such as barcodes and two-dimensional codes, for barcode reading operations. However, traditional lens groups used in barcode scanners are difficult to balance miniaturized design and good imaging quality. Summary of the Utility Model

[0003] Based on this, in view of the above technical problems, it is necessary to provide an autofocus lens group, an imaging module and an electronic device that can achieve the effect of balancing miniaturized design and good imaging quality.

[0004] In a first aspect, the present application provides an autofocus lens group, which sequentially includes, from the object side to the image side along the optical axis:

[0005] A first lens with positive optical power, wherein the object side surface and the image side surface of the first lens are both convex surfaces;

[0006] A second lens with positive optical power, wherein the object side surface of the second lens is convex and the image side surface is concave;

[0007] A third lens with negative optical power, wherein the object side surface of the third lens is convex and the image side surface is concave;

[0008] A fourth variable-focus lens, at least part of which can be deformed to change the effective focal length;

[0009] A fifth lens with negative optical power, wherein the object side surface and the image side surface of the fifth lens are both concave surfaces;

[0010] A sixth lens with positive optical power, wherein the object side surface and the image side surface of the sixth lens are both convex surfaces;

[0011] A seventh lens with positive optical power, wherein the object side surface and the image side surface of the seventh lens are both convex surfaces;

[0012] The fifth lens and the sixth lens are cemented together, and the autofocus lens group satisfies the conditional formula:

[0013] 0 < |f5 / f| ≤ 0.5;

[0014] 0 < f6 / f ≤ 0.5;

[0015] Wherein, f5 is the effective focal length of the fifth lens, f6 is the effective focal length of the sixth lens, and f is the effective focal length of the autofocus lens group.

[0016] In a second aspect, the present application provides an imaging module, including a photosensitive element and the above-mentioned autofocus lens group, and the photosensitive element is disposed on the image side of the seventh lens.

[0017] In a third aspect, the present application provides an electronic device, including the above-mentioned electronic device.

[0018] For the above-mentioned autofocus lens group, through reasonable design of the optical power and surface shape of each lens, and in cooperation with the fourth variable-focus lens disposed between the third lens and the fifth lens, when the autofocus lens group images an object within a relatively large object distance range (for example, within the object distance range of 100 mm - 2000 mm), the aberration can be effectively corrected, high resolution and good imaging quality can be achieved, clear imaging of a nearby object can be satisfied, the code scanning requirements for different object distances can be met, the code scanning efficiency and accuracy can be improved, and at the same time, it is also beneficial to compress the on-axis size of the autofocus lens group. Meanwhile, a fourth variable-focus lens is provided in the autofocus lens group, and the effective focal length of the fourth variable-focus lens is changed by the deformation of the fourth variable-focus lens, thereby changing the object distance of the autofocus lens group to realize the autofocus function of the autofocus lens group. It can not only achieve fast and large-range focusing, but also reduce the space occupied by the focusing mechanism in the optical axis direction, which is beneficial to realizing miniaturized design. Thus, the above-mentioned autofocus lens group can take into account the effects of miniaturized design, good imaging quality, and large-range focusing. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the autofocus lens group in some embodiments.

[0020] Figure 2 It is an MTF curve graph of the autofocus lens group in the state of an object distance of 100 mm in some embodiments.

[0021] Figure 3 It is an MTF curve graph of the autofocus lens group in the state of an object distance of 120 mm in some embodiments.

[0022] Figure 4 It is an MTF curve graph of the autofocus lens group in the state of an object distance of 340 mm in some embodiments.

[0023] Figure 5 It is an MTF curve graph of the autofocus lens group in the state of an object distance of 1000 mm in some embodiments.

[0024] Figure 6 It is an MTF curve graph of the autofocus lens group in the state of an object distance of 2000 mm in some embodiments.

[0025] Figure 7 are the field curvature curve graph and distortion curve graph of the autofocus lens group in some embodiments.

[0026] Figure 8 is the chief ray incidence angle curve graph of the autofocus lens group in some embodiments.

[0027] Figure 9 is the lateral chromatic aberration curve graph of the autofocus lens group in some embodiments.

[0028] Figure 10 is the relative illumination diagram of the autofocus lens group in some embodiments.

[0029] Reference numerals:

[0030] 10. Autofocus lens group; L1. First lens; 11. First cemented lens group; L2. Second lens; L3. Third lens; L4. Fourth variable-focus lens; 121. First liquid part; 122. Second liquid part; 123. First protective element; 124. Second protective element; 13. Second cemented lens group; L5. Fifth lens; L6. Sixth lens; L7. Seventh lens; 14. Imaging surface; STO. Diaphragm; 15. Filter. Detailed implementation manners

[0031] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0032] Please refer to Figure 1 , Figure 1FIG. 0 shows a schematic structural diagram of the autofocus lens group 10 in some embodiments of the present application. The autofocus lens group 10 provided by the present application sequentially includes a first lens L1, a second lens L2, a third lens L3, a fourth variable-focus lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7 along the optical axis from the object side to the image side. The autofocus lens group 10 can form an imaging module with a photosensitive element, and the photosensitive element can be disposed on the image side of the seventh lens L7. The autofocus lens group 10 further includes an imaging plane 14, which can be understood as a virtual plane formed by the convergence of imaging light rays. The light rays collected by the autofocus lens group 10 can be adjusted by the first lens L1, the second lens L2, the third lens L3, the fourth variable-focus lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 in sequence and then projected onto the imaging plane 14. The imaging plane 14 can coincide with the photosensitive surface of the photosensitive element, and the photosensitive element can convert the light rays into electrical signals for transmission, so that the autofocus lens group 10 can realize the imaging function. The photosensitive element includes, but is not limited to, a charge-coupled device (CCD) or a complementary metal-oxide semiconductor sensor (CMOS Sensor). In some embodiments, the first lens L1, the second lens L2, the third lens L3, the fourth variable-focus lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are coaxially arranged, and the common axis of each element is regarded as the optical axis of the autofocus lens group 10.

[0033] The imaging module including the autofocus lens group 10 provided by the present application can be used in an electronic device, for example, it can be installed in the housing of the electronic device. The electronic device includes, but is not limited to, a barcode scanner, an industrial imaging device, etc. In the present application, taking the barcode scanner as an example, the electronic device can be used to capture encoded identifiers such as barcodes and QR codes. The autofocus lens group 10 provided by the present application can realize fast and accurate focusing functions, and has good imaging quality, which can meet the requirements of efficient and accurate code reading.

[0034] Further, in some embodiments, the fourth variable-focus lens L4 can at least partially deform when powered on, so that the effective focal length of the fourth variable-focus lens L4 changes, thereby changing the object distance of the autofocus lens group 10 and realizing the autofocus function. Moreover, as the voltage applied to the fourth variable-focus lens L4 changes, the effective focal length of the fourth variable-focus lens L4 also changes, which is beneficial to flexibly adjust the object distance of the autofocus lens group 10 to realize fast, efficient, and accurate imaging of objects at different object distances.

[0035] In some embodiments, the first lens L1 has a positive focal power, and both the object side and the image side of the first lens L1 are convex surfaces. The second lens L2 has a positive focal power, the object side of the second lens L2 is convex, and the image side is concave. The third lens L3 has a negative focal power, the object side of the third lens L3 is convex, and the image side is concave. The fifth lens L5 has a negative focal power, and both the object side and the image side of the fifth lens L5 are concave surfaces. The sixth lens L6 has a positive focal power, and both the object side and the image side of the sixth lens L6 are convex surfaces. The seventh lens L7 has a positive focal power, and both the object side and the image side of the seventh lens L7 are convex surfaces. In the present application, when describing the object side of a certain element, it can be understood as the surface of the element facing the image side. When describing the image side of a certain element, it can be understood as the surface of the element facing the image side. When describing the object side of a certain element as a convex surface, it can be understood that the object side of the element protrudes towards the object side. When describing the image side of a certain element as a convex surface, it can be understood that the image side of the element protrudes towards the image side.

[0036] In some embodiments, the fifth lens L5 and the sixth lens L6 are cemented together, and the autofocus lens group 10 satisfies the conditional formula: 0 < |f5 / f| ≤ 0.5; 0 < f6 / f ≤ 0.5; where f5 is the effective focal length of the fifth lens L5, f6 is the effective focal length of the sixth lens L6, and f is the effective focal length of the autofocus lens group 10.

[0037] Among them, the positive focal power of the first lens L1 combined with the double convex surface type of the first lens L1 is conducive to converging the collected light towards the image side, thereby facilitating the shortening of the on-axis size of the autofocus lens group 10 and achieving a miniaturized design. The positive focal power and the convex-concave surface type of the second lens L2, combined with the focal power and surface type of the first lens L1, can achieve a reasonable transition of light. Combined with the negative focal power and the convex-concave surface type of the third lens L3, it can suppress the generation of aberrations such as distortion, improve the imaging quality of the autofocus lens group 10, and at the same time is conducive to reducing the burden of the lenses on the image side of the third lens L3 to deflect light. While improving the imaging quality, it is conducive to reducing the surface type complexity of the lenses on the image side of the third lens L3, thereby reducing the tolerance sensitivity and forming yield rate of each lens. The negative focal power and the double concave surface type of the fifth lens L5, as well as the positive focal power and the double convex surface type of the sixth lens L6, combined with the design of cementing the fifth lens L5 and the sixth lens L6, can smoothly transition the light passing through the fourth variable-focus lens L4 to the image side and constrain the trend of light in each field of view, thereby facilitating the suppression of the generation of aberrations such as chromatic aberration, so that the autofocus lens group 10 can have good imaging quality under different object distance states. The positive focal power of the seventh lens L7, combined with the double convex surface type of the seventh lens L7, can reasonably deflect the light transitioned by the fifth lens L5 and the sixth lens L6 to the imaging surface 14, improving the matching degree of the incident angle of light on the imaging surface 14 with the photosensitive element, thereby facilitating the improvement of the resolution and imaging quality of the autofocus lens group 10.

[0038] When the above conditional expression is satisfied, it is possible to reasonably configure the ratio of the fifth lens L5 to the effective focal length of the autofocus lens group 10 and the ratio of the sixth lens L6 to the effective focal length of the autofocus lens group 10. In combination with the optical power and surface shape designs of the fifth lens L5 and the sixth lens L6, and the design of gluing the fifth lens L5 and the sixth lens L6 together, the combination of the fifth lens L5 and the sixth lens L6 can have an appropriate refractive power to deflect light rays, suppress the generation of aberrations such as chromatic aberration. In combination with the design of arranging the fourth zoom lens L4 between the third lens L3 and the fifth lens L5, the autofocus lens group 10 has good imaging quality under different object distance conditions.

[0039] For the above autofocus lens group 10, through the reasonable design of the optical power and surface shape of each lens, in combination with the fourth zoom lens L4 arranged between the third lens L3 and the fifth lens L5, when the autofocus lens group 10 images an object within a large object distance range (for example, within an object distance range of 100 mm - 2000 mm), the aberrations can be effectively corrected, high resolution and good imaging quality can be achieved, clear imaging of a nearby object can be satisfied, the code scanning requirements for different object distances can be met, the code scanning efficiency and accuracy can be improved, and at the same time, it is also beneficial to compress the on-axis size of the autofocus lens group 10. At the same time, by setting the fourth zoom lens L4 in the autofocus lens group 10, the effective focal length of the fourth zoom lens L4 is changed by the deformation of the fourth zoom lens L4, thereby changing the object distance of the autofocus lens group 10 to achieve the autofocus function of the autofocus lens group 10. It can not only achieve fast and large-range focusing, but also reduce the space occupied by the focusing mechanism in the optical axis direction, which is beneficial to realizing a miniaturized design. Thus, the above autofocus lens group 10 can take into account the effects of miniaturized design, good imaging quality, and large-range focusing, and meet the accurate and efficient code scanning requirements for objects with different object distances such as two-dimensional codes and barcodes.

[0040] In some embodiments, the second lens L2 and the third lens L3 are glued together to form the first glued lens group 11, and the fifth lens L5 and the sixth lens L6 are glued together to form the second glued lens group 13. The design of the two glued lens groups in combination with the optical power and surface shape designs of each lens can effectively correct aberrations such as chromatic aberration of the autofocus lens group 10 and improve the imaging quality.

[0041] Further, in the present application, the specific type and structural setting of the fourth variable-focus lens L4 are not limited, as long as the effective focal length of the fourth variable-focus lens L4 is adjustable when powered on to achieve the autofocus function of the autofocus lens group 10. In some embodiments, the fourth variable-focus lens L4 is a liquid lens. The fourth variable-focus lens L4 includes an adjacent first liquid portion 121 and a second liquid portion 122, and the second liquid portion 122 may be located on the image side of the first liquid portion 121. The first liquid portion 121 and the second liquid portion 122 have an interface. The fourth variable-focus lens L4 can change the shapes of the first liquid portion 121 and the second liquid portion 122 when powered on, thereby changing the shape of the interface, and further changing the refraction effect of the interface on light, thereby achieving the effect of changing the effective focal length of the fourth variable-focus lens L4. In some embodiments, the first liquid portion 121 may include a conductive solution such as an aqueous solution, and the second liquid portion 122 may include an oily liquid such as a silicone oil solution.

[0042] In some embodiments, the fourth variable-focus lens L4 may further include a first protection element 123 and a second protection element 124. The first protection element 123 is adjacent to the first liquid portion 121 and is disposed on the object side of the first liquid portion 121, and the second protection element 124 is adjacent to the second liquid portion 122 and is disposed on the image side of the second liquid portion 122. The first protection element 123 and the second protection element 124 may both be flat glass, which is used to provide a protection effect on the first liquid portion 121 and the second liquid portion 122 to improve the structural reliability of the fourth variable-focus lens L4.

[0043] In some embodiments, the effective focal length f4 of the fourth variable-focus lens L4 satisfies the conditional formula: -5.5D ≤ Φ4 ≤ 13D. That is to say, when the voltage applied to the fourth variable-focus lens L4 changes, the optical power of the fourth variable-focus lens L4 can change within the range of -5.5D to 13D, and can be any value within the range of -5.5D to 13D to change the effective focal length and object distance of the autofocus lens group 10. Meeting the above conditional formula enables the effective focal length change range of the fourth variable-focus lens L4 to meet the large-range focusing requirements of the autofocus lens group 10 to meet the code scanning requirements of objects to be photographed at different object distances. At the same time, it also enables the effective focal length change range of the fourth variable-focus lens L4 to be adapted to the optical power and surface shape design of each lens, and good imaging quality can be achieved within different object distance ranges to meet the requirements of efficient and accurate code scanning. In some embodiments, when the fourth variable-focus lens L4 meets the above conditional formula, the effective focal length f and object distance u of the autofocus lens group 10 respectively satisfy the conditional formulas: 15mm ≤ f ≤ 17mm; 100mm ≤ u ≤ 2000mm, which can meet the large-range focusing requirements.

[0044] In some embodiments, take the object distance states of the autofocus lens group 10 corresponding to five effective focal length states of the fourth variable-focus lens L4 as an example. When the optical power of the fourth variable-focus lens L4 is 12.7 D, the effective focal length of the autofocus lens group 10 is 15.39 mm and the object distance is 100 mm. When the optical power of the fourth variable-focus lens L4 is 9.89 D, the effective focal length of the autofocus lens group 10 is 15.52 mm and the object distance is 120 mm. When the optical power of the fourth variable-focus lens L4 is 0, the effective focal length of the autofocus lens group 10 is 15.99 mm and the object distance is 340 mm. When the optical power of the fourth variable-focus lens L4 is -3.95 D, the effective focal length of the autofocus lens group 10 is 16.16 mm and the object distance is 1000 mm. When the optical power of the fourth variable-focus lens L4 is -5.1 D, the effective focal length of the autofocus lens group 10 is 16.21 mm and the object distance is 2000 mm. Of course, according to the change of the voltage applied to the fourth variable-focus lens L4, the optical power of the fourth variable-focus lens L4 can be any value between -5.5 D and 13 D, and when the optical power of the fourth variable-focus lens L4 changes arbitrarily between -5.5 D and 13 D, the object distance of the autofocus optical system can be any value between 100 mm and 2000 mm, which is beneficial to adapting to the objects with different object distances and achieving good imaging quality.

[0045] In some embodiments, the autofocus lens group 10 further includes a diaphragm STO. The diaphragm STO is disposed between the fourth variable-focus lens L4 and the fifth lens L5. Cooperating with the structure and position design of the fourth variable-focus lens L4 and other lenses, it can improve the relative illumination and imaging quality of the imaging. At the same time, due to the design of the fourth variable-focus lens L4, the autofocus lens group 10 can break through the depth-of-field limit without sacrificing the aperture size of the diaphragm STO. For example, the aperture value of the diaphragm STO can be 4.5 or a lower value, which is beneficial to increasing the light input amount of the autofocus lens group 10 and improving the relative illumination and imaging quality.

[0046] In some embodiments, the object sides and image sides of the first lens L1, the second lens L2, the third lens L3, the fifth lens L5, the sixth lens L6, and the seventh lens L7 can all be spherical surfaces. It should be noted that the above embodiments are only examples of some embodiments of the present application. In some embodiments, the surfaces of each lens can all be aspherical surfaces, or can be any combination of aspherical surfaces or spherical surfaces. In some embodiments, the materials of the first lens L1, the second lens L2, the third lens L3, the fifth lens L5, the sixth lens L6, and the seventh lens L7 can all be glass or all be plastic. Lenses made of plastic materials can reduce the weight of the autofocus lens group 10 and lower the production cost. And lenses made of glass materials endow the autofocus lens group 10 with excellent optical performance and high temperature resistance. It should be noted that the materials of each lens in the autofocus lens group 10 can also be any combination of glass and plastic, and do not necessarily have to be all glass or all plastic.

[0047] In some embodiments, the autofocus lens group 10 further includes a filter 15. The filter 15 is disposed between the seventh lens L7 and the imaging surface 14. The filter 15 is used to filter out interfering light to prevent the interfering light from hitting the imaging surface 14 and affecting normal imaging. The filter 15 includes, but is not limited to, an infrared cut-off filter element. According to different filtering requirements, the filter 15 can also have other settings.

[0048] In some embodiments, the autofocus lens group 10 satisfies the conditional formula: 2 ≤ |fB1 / f| ≤ 2.5; where fB1 is the effective focal length of the first cemented lens group 11. For example, |fB1 / f| can be 2, 2.1, 2.2, 2.3, 2.4, or 2.5. When the above conditional formula is satisfied, the ratio of the effective focal length of the first cemented lens group 11 to the autofocus lens group 10 can be reasonably configured, so that the first cemented lens group 11 can reasonably transition the light collected by the first lens L1, reasonably constrain the trend of the light, suppress the generation of aberrations such as distortion, and reduce the burden on the lenses on the image side of the first cemented lens group 11 to deflect the light, thereby being beneficial to improving the imaging quality of the autofocus lens group 10 and reducing the tolerance sensitivity.

[0049] In some embodiments, the autofocus lens group 10 satisfies the conditional formula: 2 ≤ |fB2 / f| ≤ 2.5; where fB2 is the effective focal length of the second cemented lens group 13. For example, |fB2 / f| can be 2, 2.1, 2.2, 2.6, 2.4, or 2.5. When the above conditional formula is satisfied, the ratio of the effective focal length of the second cemented lens group 13 to the autofocus lens group 10 can be reasonably configured, so that the second cemented lens group 13 has an appropriate optical power to deflect the light, constrain the trend of the light, and cooperate with the optical power and surface shape design of the lenses on the object side and image side of the second cemented lens group 13, which is beneficial to improving the imaging quality and imaging brightness of the autofocus lens group 10.

[0050] In some embodiments, the autofocus lens group 10 satisfies the conditional expression: 2 ≤ f1 / f ≤ 2.5; where f1 is the effective focal length of the first lens L1. For example, f1 / f can be 2, 2.1, 2.2, 2.3, 2.4, or 2.5. When the above conditional expression is satisfied, the ratio of the effective focal length of the first lens L1 to that of the autofocus lens group 10 can be reasonably configured, so that the first lens L1 has sufficient refractive power to converge light, which is beneficial to compressing the on-axis size of the autofocus lens group 10 while taking into account the improvement of imaging quality.

[0051] In some embodiments, the autofocus lens group 10 satisfies the conditional expressions: 1 ≤ f2 / f ≤ 1.2; 0.5 ≤ |f3 / f| ≤ 1; where f2 is the effective focal length of the second lens L2, and f3 is the effective focal length of the third lens L3. For example, f2 / f can be 1, 1.1, or 1.2, and |f3 / f| can be 0.5, 0.6, 0.7, 0.8, 0.9, or 1. When the above conditional expressions are satisfied, the ratio of the effective focal length of the second lens L2 to that of the autofocus lens group 10, and the ratio of the effective focal length of the third lens L3 to that of the autofocus lens group 10 can be reasonably configured. In combination with the design of gluing the second lens L2 and the third lens L3, the second lens L2 and the third lens L3 can form a good cooperation to smoothly transition the passing light, suppress the generation of aberrations such as distortion, and reduce the burden of deflecting light rays on each lens on the image side of the second cemented lens group 13. Thereby, it is beneficial to improve the imaging quality of the autofocus lens group 10 and reduce the tolerance sensitivity.

[0052] In some embodiments, the autofocus lens group 10 satisfies the conditional expression: 0.5 ≤ f7 / f ≤ 1.5; where f7 is the effective focal length of the seventh lens L7. For example, f7 / f can be 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.3, 1.4, or 1.5. When the above conditional expression is satisfied, the ratio of the effective focal length of the seventh lens L7 to that of the autofocus lens group 10 can be reasonably configured, so that the seventh lens L7 has appropriate refractive power to deflect light rays onto the imaging surface 14, improving the resolution and imaging quality of the autofocus lens group 10.

[0053] In some embodiments, the autofocus lens group 10 satisfies the conditional expression: 1 ≤ fmax / fmin ≤ 1.1; where fmax is the maximum effective focal length of the autofocus lens group 10, and fmin is the minimum effective focal length of the autofocus lens group 10. The specific numerical range of the effective focal length of the autofocus lens group 10 can be obtained with reference to the above description. When the above conditional expression is satisfied, in combination with the design of the fourth variable-focus lens L4, the autofocus lens group 10 has a sufficient focal length and object distance change range, and can achieve the effect of efficient and large-range focusing.

[0054] In some embodiments, the autofocus lens group 10 satisfies the conditional expression: 1≤s / f≤1.5; where s is the distance on the optical axis from the object side of the first lens L1 to the image side of the seventh lens L7. For example, s / f can be 1, 1.1, 1.2, 1.3, 1.4, or 1.5. When the above conditional expression is satisfied, each lens can have sufficient on-axis space to constrain the trend of light rays, which is beneficial to compressing the size of the autofocus lens group 10 while maintaining good imaging quality, thereby facilitating the realization of miniaturized design.

[0055] In some embodiments, the autofocus lens group 10 satisfies the conditional expression: 0<|h / f|≤0.5; where h is the semi-image height of the autofocus lens group 10. For example, |h / f| can be 0.1, 0.2, 0.3, 0.4, or 0.5. Satisfying the above conditions can reasonably configure the ratio of the semi-image height to the effective focal length of the autofocus lens group 10, which is beneficial to reasonably configuring the field of view angle and aperture of the autofocus lens group 10, thereby facilitating the realization of large-range image acquisition and increasing the light input amount, and improving the relative illumination of the image.

[0056] In some embodiments, both the object side and the image side of the seventh lens L7 are spherical surfaces, and the autofocus lens group 10 satisfies the conditional expression: R71 = |R72|; where R71 is the curvature radius of the object side of the seventh lens L7, and R72 is the curvature radius of the image side of the seventh lens L7. When the above conditional expression is satisfied, the curvature radii of the object side and the image side of the seventh lens L7 are equal. Combining with the optical power and surface shape design of each lens, it is beneficial to reduce the design and molding difficulty of the seventh lens L7, reduce the mold opening cost of optical cold processing, reduce the preparation cost, and at the same time can meet the requirements of imaging quality.

[0057] In some embodiments, the autofocus lens group 10 satisfies the conditional expressions: TTL≤30.81mm; Φ≤10.6mm; where TTL is the distance on the optical axis from the object side of the first lens L1 to the imaging surface 14 of the autofocus lens group 10, that is, the total optical length of the autofocus lens group 10, and Φ is the maximum effective optical diameter of the autofocus lens group 10. Thus, the autofocus lens group 10 can achieve miniaturized design, can be made into an M12 threaded lens, which is beneficial to the assembly and application in electronic devices such as scanners, and meets the miniaturization requirements of electronic devices.

[0058] The following Table 1 shows the parameters of the autofocus lens group 10 in some embodiments. Among them, each part from the object surface to the imaging surface 14 is arranged in the order from top to bottom in Table 1. In the corresponding embodiment of Table 1, the object distance of the autofocus lens group 10 is 340mm.

[0059] Table 1

[0060]

[0061] When the object distance of the autofocus lens group 10 is 100 mm, the parameters of the fourth variable-focus lens L4 are given in Table 2 below. When the object distance of the autofocus lens group 10 is 120 mm, the parameters of the fourth variable-focus lens L4 are given in Table 3 below. When the object distance of the autofocus lens group 10 is 1000 mm, the parameters of the fourth variable-focus lens L4 are given in Table 4 below. When the object distance of the autofocus lens group 10 is 2000 mm, the parameters of the fourth variable-focus lens L4 are given in Table 5 below. The meanings of the parameters in Tables 2 - 5 can be obtained by referring to Table 1 and will not be elaborated here.

[0062] Table 2

[0063]

[0064] Table 3

[0065]

[0066] Table 4

[0067]

[0068] Table 5

[0069]

[0070] In some embodiments, the autofocus lens group 10 also satisfies the data in Tables 6 and 7 below. The effects that can be obtained by satisfying the following data can be obtained from the above description and will not be elaborated here. In Tables 6 and 7, when some data changes with the object distance of the autofocus lens group 10, the corresponding parameters are for an object distance of 340 mm.

[0071] Table 6

[0072]

[0073] Table 7

[0074]

[0075] In some embodiments, through the reasonable design of the optical power and surface shape of each lens and the fourth variable-focus lens L4, the autofocus lens group 10 has good imaging quality for the visible light band of 436 nm - 656 nm under different object distance conditions. When the object distance is 340 mm, the effective focal length of the autofocus lens group 10 is 16.16 mm, the relative aperture D / f = 4.5, the full field of view FOV = 30°, the image height is 8.9 mm, the full field distortion is less than 0.5%, and the maximum chief ray angle is less than 6.3°. The autofocus lens group 10 can achieve the effects of small size, large-range object distance focusing, large image plane, and high imaging quality. For example, it can be matched with large target surface photosensitive elements smaller than 1 / 1.8 inches.

[0076] Please refer to Figures 2 - 10 as shown Figure 2 The following are the modulation transfer function (MTF) curves of the autofocus lens group 10 at an object distance of 100 mm in some embodiments, Figure 3 the MTF curves of the autofocus lens group 10 at an object distance of 120 mm in some embodiments, Figure 4 the MTF curves of the autofocus lens group 10 at an object distance of 340 mm in some embodiments, Figure 5 the MTF curves of the autofocus lens group 10 at an object distance of 1000 mm in some embodiments, Figure 6 the MTF curves of the autofocus lens group 10 at an object distance of 2000 mm in some embodiments. In the MTF curves Figures 2 - 6 shown, the abscissa represents the spatial frequency (lp / mm), and the ordinate represents the normalized contrast. Figure 7 The following are the curvature of field curves and distortion curves of the autofocus lens group 10 in some embodiments. Among them, the abscissa of the curvature of field curve represents the magnitude of the curvature of field (mm) of the visible light wavelength, the ordinate represents the field of view angle (°), the abscissa of the distortion curve represents the percentage of distortion of the visible light wavelength (%), and the ordinate represents the field of view angle (°). Figure 8 The following is the chief ray incidence angle curve of the autofocus lens group 10 in some embodiments. Among them, the abscissa represents the normalized image height, and the ordinate represents the chief ray angle value. Figure 9 The following is the lateral chromatic aberration curve of the autofocus lens group 10 in some embodiments. Among them, the abscissa represents the magnitude of the lateral chromatic aberration (um), and the ordinate represents the actual image height (mm). Figure 10 The following is the relative illumination diagram of the autofocus lens group 10 in some embodiments. Among them, the abscissa represents the normalized image height, and the ordinate represents the percentage value of the illumination relative to the center. Figures 7 - 10 All correspond to the object distance state of the autofocus lens group 10 at 340 mm.

[0077] It can be seen from Figures 2 - 10 that within the object distance range of 120 mm - 2000 mm of the autofocus lens group 10, when the spatial frequency is 150 lp / mm, the MTF value is greater than 0.3; within the object distance range of 100 mm - 120 mm, when the spatial frequency is 110 lp / mm, the MTF value is greater than 0.3. The absolute value of the optical distortion is less than 0.5% within the full field of view range (φ8.9 mm), the relative illumination of the edge field of view is greater than 75%, the maximum chief ray angle is less than 6.3°, and aberrations such as chromatic aberration and distortion are effectively corrected, and good imaging quality is achieved at different object distance states.

[0078] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0079] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. An autofocus lens assembly, characterized in that: Along the optical axis from the object side to the image side, it includes: A first lens having positive refractive power, wherein both the object-side surface and the image-side surface of the first lens are convex surfaces; a second lens having positive refractive power, wherein the object-side surface of the second lens is convex and the image-side surface is concave; a third lens having negative optical power, wherein the object-side surface of the third lens is convex and the image-side surface is concave; a fourth variable-focus lens, at least a portion of which is deformable so that an effective focal length changes; a fifth lens having negative optical power, wherein both the object-side surface and the image-side surface of the fifth lens are concave; a sixth lens having positive refractive power, wherein both the object-side surface and the image-side surface of the sixth lens are convex surfaces; a seventh lens having positive refractive power, wherein both the object-side surface and the image-side surface of the seventh lens are convex surfaces; The fifth lens and the sixth lens are glued together, and the autofocus lens group satisfies the conditional formula: 0<|f5 / f|≤0.5; 0 <f6 / f≤0.5; Among them, f5 is the effective focal length of the fifth lens, f6 is the effective focal length of the sixth lens, and f is the effective focal length of the autofocus lens group.

2. The autofocus lens assembly according to claim 1, characterized in that: The second lens and the third lens are cemented together to form a first cemented lens group.

3. The autofocus lens assembly according to claim 2, characterized in that: The autofocus lens group satisfies the conditional formula: 2≤|fB1 / f|≤2.5; Wherein, fB1 is the effective focal length of the first cemented lens assembly.

4. The autofocus lens assembly according to claim 1, characterized in that: The fifth lens and the sixth lens form a second cemented lens group, and the autofocus lens group satisfies the conditional formula: 2≤|fB2 / f|≤2.5; Wherein, fB2 is the effective focal length of the second cemented lens group.

5. The autofocus lens assembly according to claim 1, characterized in that: The autofocus lens group satisfies at least one of the following conditions: 2≤f1 / f≤2.5; 1≤f2 / f≤1.2; 0.5≤|f3 / f|≤1; 0.5≤f7 / f≤1.5; Among them, f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, and f7 is the effective focal length of the seventh lens.

6. The autofocus lens assembly according to claim 1, characterized in that: The autofocus lens group satisfies at least one of the following conditions: 1≤fmax / fmin≤1.1; 1≤s / f≤1.5; 0<|h / f|≤0.5; TTL≤30.81mm; Φ≤10.6mm; Among them, fmax is the maximum effective focal length of the autofocus lens group, fmin is the minimum effective focal length of the autofocus lens group, s is the distance from the object side surface of the first lens to the image side surface of the seventh lens on the optical axis, h is the half image height of the autofocus lens group, TTL is the distance from the object side surface of the first lens to the imaging surface of the autofocus lens group on the optical axis, and Φ is the maximum effective optical diameter of the autofocus lens group.

7. The autofocus lens assembly according to claim 1, characterized in that: The autofocus lens group satisfies the conditional formula: -5.5D≤Φ4≤13D; 15mm≤f≤17mm; 100mm≤u≤2000mm; Wherein, Φ4 is the optical focal length of the fourth variable focus lens, and u is the object distance of the autofocus lens group.

8. The autofocus lens assembly according to claim 1, characterized in that: The object side surface and the image side surface of the seventh lens are both spherical surfaces, and the autofocus lens group satisfies the conditional formula: R71=|R72|; Wherein, R71 is the curvature radius of the object side surface of the seventh lens, and R72 is the curvature radius of the image side surface of the seventh lens.

9. A camera module, characterized in that: It comprises a photosensitive element and the autofocus lens group as claimed in any one of claims 1 to 8, wherein the photosensitive element is arranged on the image side of the seventh lens.

10. An electronic device, characterized in that: Comprising the electronic device as claimed in claim 9.

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