A large-surface half-group mobile industrial macro lens

Abstract

The present invention discloses a large-target-surface half-group mobile industrial macro lens, in which a first lens group that can move forward and backward along the optical axis, a fixed second lens group and a protective glass are sequentially arranged along the optical axis from the object side to the image side, and a variable diaphragm that moves with the first lens group is arranged in the first lens group; the first lens group moves forward and backward along the optical axis, so that the spacing between the first lens group and the second lens group is adjustable to achieve continuous zooming; during the continuous zooming process, the variable diaphragm moves with the first lens group. The large-target-surface half-group mobile industrial macro lens provided by the present invention can select different object distances and magnifications according to different usage scenarios, and the maximum imaging circle diameter is greater than 29 mm, which can match a 1.75-inch image sensor.

Description

Technical Field

[0001] The invention belongs to the field of optical lenses, and in particular relates to a large-target-surface half-group mobile industrial macro lens. Background Art

[0002] A macro lens is a special lens used for macro photography, mainly used to shoot very fine objects. For example, a Chinese patent document with publication number CN105093504A discloses a macro lens for attachment to the front end of the lens of an imaging device. The macro lens includes a first lens unit with positive refractive power, a second lens unit with positive refractive power, and a third lens unit with negative refractive power from the object side to the image side. For example, a Chinese patent document with publication number CN102053348A discloses a macro lens system and a pickup device including the macro lens system, wherein the macro lens system includes, in order from the object side to the image side, a first lens group with positive refractive power; a second lens group with negative refractive power; a third lens group with positive refractive power; a fourth lens group with positive refractive power; and a fifth lens group with negative refractive power, wherein, during the focusing process, the first lens group, the third lens group, and the fifth lens group are fixed, and the second lens group and the fourth lens group move.

[0003] There are two types of industrial macro lenses on the market: fixed magnification and variable magnification. Fixed magnification industrial macro lenses have a larger image circle diameter, which can match larger image sensors and have a larger field of view; but due to the fixed magnification, they cannot meet the needs of various scenarios. Variable magnification industrial macro lenses can adapt to different observation objects by adjusting the object distance and magnification, but the image circle diameter of the variable magnification industrial macro lenses on the market is smaller, resulting in a smaller field of view for detection and observation.

[0004] It can be seen from this that it is urgent to develop an industrial macro lens with a variable magnification and a larger imaging circle diameter. Summary of the invention

[0005] The present invention discloses a large-target-surface half-group mobile industrial macro lens, which can select different object distances and magnifications according to different usage scenarios, and has a maximum imaging circle diameter greater than 29 mm, which can match a 1.75-inch image sensor.

[0006] The technical solution adopted by the present invention is:

[0007] A large-target-surface half-group mobile industrial macro lens comprises a first lens group that can move forward and backward along the optical axis, a fixed second lens group and a protective glass arranged in sequence from the object side to the image side along the optical axis, wherein a variable diaphragm that moves with the first lens group is arranged in the first lens group; the first lens group moves forward and backward along the optical axis so that the spacing between the first lens group and the second lens group is adjustable to achieve continuous magnification change; during the continuous magnification change process, the variable diaphragm moves with the first lens group.

[0008] The focal lengths of the first lens group and the second lens group satisfy the following conditional formula:

[0009] 0.1<|f1 / f2|<0.5

[0010] 0.5<|f1 / f0|<1.5

[0011] 2.0<|f2 / f0|<5.0

[0012] Where f1 represents the focal length of the first lens group, f2 represents the focal length of the second lens group, and f0 represents the focal length of the entire lens.

[0013] Preferably, the focal lengths of the first lens group and the second lens group satisfy the following conditional formula:

[0014] 0.25<|f1 / f2|≤0.28

[0015] 0.8<|f1 / f0|<1.1

[0016] 2.5<|f2 / f0|<4.3

[0017] Where f1 represents the focal length of the first lens group, f2 represents the focal length of the second lens group, and f0 represents the focal length of the entire lens.

[0018] Further, the first lens group includes: a first lens with a convex surface on the object side and a flat surface on the image side, a second lens with a convex surface on the object side and a concave surface on the image side, a third lens with a convex surface on the object side and a concave surface on the image side, a fourth lens with a concave surface on the object side and a concave surface on the image side, a fifth lens with a convex surface on the object side and a convex surface on the image side, a sixth lens with a flat surface on the object side and a convex surface on the image side, and a seventh lens with a concave surface on the object side and a convex surface on the image side;

[0019] The concave surface of the fourth lens and the convex surface of the fifth lens are glued together to form a first glued lens, and the fourth lens is close to the object plane. The convex surface of the sixth lens and the concave surface of the seventh lens are glued together to form a second glued lens, and the sixth lens is close to the object plane.

[0020] The second lens group includes an eighth lens and a ninth lens, and the eighth lens is close to the object plane;

[0021] The object side of the eighth lens is concave and the image side is convex. The object side of the ninth lens is concave and the image side is convex. The convex surface of the eighth lens and the concave surface of the ninth lens are cemented to form a third cemented lens.

[0022] The variable iris is arranged between the third lens and the fourth lens of the first lens group, and the aperture size of the variable iris is adjustable.

[0023] The protective glass is placed behind the image side of the ninth lens.

[0024] Further, the focal length of the first lens ranges from 40.0 to 80.0 mm, the focal length of the second lens ranges from 40.0 to 60.0 mm, the focal length of the third lens ranges from -30.0 to -20.0 mm, the focal length of the fourth lens ranges from -5.0 to -15.0 mm, the focal length of the fifth lens ranges from 10.0 to 20.0 mm, the focal length of the sixth lens ranges from 15.0 to 25.0 mm, the focal length of the seventh lens ranges from -40.0 to -20.0 mm, the focal length of the eighth lens ranges from 30.0 to 45.0 mm, and the focal length of the ninth lens ranges from -55.0 to -45.0 mm.

[0025] Further preferably, the focal length of the first lens is in the range of 48.5 to 74.4 mm, the focal length of the second lens is in the range of 46.3 to 58.7 mm, the focal length of the third lens is in the range of -25.3 to -24.4 mm, the focal length of the fourth lens is in the range of -12.0 to -11.5 mm, the focal length of the fifth lens is in the range of 14.0 to 14.2 mm, the focal length of the sixth lens is in the range of 19.4 to 20.5 mm, the focal length of the seventh lens is in the range of -31.5 to -31.2 mm, the focal length of the eighth lens is in the range of 39.5 to 40.0 mm, and the focal length of the ninth lens is in the range of -50.3 to -49.3 mm.

[0026] During the zoom process from low power to high power, the distance between the first lens group and the second lens group decreases, and the distance d1 from the image side of the first lens group to the object side of the second lens group satisfies the following formula: 5.0 mm ≤ d1 ≤ 60.0 mm.

[0027] The industrial macro lens has a working distance of 80.0-250.0 mm and a magnification of 0.2x-1.0x.

[0028] The maximum imaging circle diameter of the industrial macro lens is greater than 29 mm, matching a 1.75-inch image sensor.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] By using the half-group moving method and changing the distance between the first lens group and the second lens group, a zoom range of 0.2x-1.0x can be achieved, and the working distance covers 80.0-250.0mm. Different object distances and magnifications can be selected according to different usage scenarios. The maximum image circle diameter is designed to be 29.0mm, which can be used with a 1.75-inch image sensor. Not only is the structure simple and easy to manufacture, which reduces production costs, but also the image quality is excellent. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the optical system structure of the large target surface half-group mobile industrial macro lens in Example 1;

[0032] Figure 2 This is the MTF curve of the large target surface half-group mobile industrial macro lens in Example 1 when the magnification is 0.25×;

[0033] Figure 3 This is the MTF curve of the large-target half-group mobile industrial macro lens in Example 1 when the magnification is 0.5×;

[0034] Figure 4 MTF curve of the large target surface half-group mobile industrial macro lens in Example 1 at a magnification of 1×;

[0035] Figure 5 This is a schematic diagram of the optical system structure of a large target surface half-group mobile industrial macro lens in Example 2;

[0036] Figure 6 This is the MTF curve of the large-target half-group mobile industrial macro lens in Example 2 when the magnification is 0.25×;

[0037] Figure 7 This is the MTF curve of the large-target half-group mobile industrial macro lens in Example 2 when the magnification is 0.5×;

[0038] Figure 8 MTF curve of the large target surface half-group mobile industrial macro lens in Example 2 at a magnification of 1×;

[0039] Fig. 9 This is a schematic diagram of the optical system structure of a large target surface half-group mobile industrial macro lens in Example 3;

[0040] Fig.10 This is the MTF curve of the large-target half-group mobile industrial macro lens in Example 3 when the magnification is 0.25×;

[0041] Fig.11 This is the MTF curve of the large-target half-group mobile industrial macro lens in Example 3 when the magnification is 0.5×;

[0042] Fig.12 MTF curve of the large-target half-group mobile industrial macro lens in Example 3 at a magnification of 1×. DETAILED DESCRIPTION

[0043] In order to make the above features and advantages of the present invention more clearly understood, embodiments are given below with reference to the accompanying drawings for detailed description.

[0044] like Figure 1 , Figure 5 and Fig. 9 As shown, the large-target-surface half-group mobile industrial macro lens provided in Examples 1-3 has a first lens group 1 that can move forward and backward along the optical axis, a fixed second lens group 2, and a protective glass 3 arranged in sequence along the optical axis from the object side to the image side, and a variable iris 14 that moves with the first lens group 1 is arranged in the first lens group 1. The first lens group 1 can move forward and backward along the optical axis, so that the spacing between the first lens group 1 and the second lens group 2 is adjustable, which is used to realize the continuous zoom function. During the zoom process, the variable iris 14 moves with the first lens group, and the relative position of the second lens group in the optical system does not change.

[0045] Specifically, the first lens group 1 includes: a first lens 11 having a convex surface on the object side and a flat surface on the image side, a second lens 12 having a convex surface on the object side and a concave surface on the image side, a third lens 13 having a convex surface on the object side and a concave surface on the image side, a fourth lens 15 having a concave surface on the object side and a concave surface on the image side, a fifth lens 16 having a convex surface on the object side and a convex surface on the image side, a sixth lens 17 having a flat surface on the object side and a convex surface on the image side, and a seventh lens 18 having a concave surface on the object side and a convex surface on the image side; the first lens group 2 includes: an eighth lens 21 having a concave surface on the object side and a convex surface on the image side, and the ninth lens 22 having a concave surface on the object side and a convex surface on the image side.

[0046] In an exemplary embodiment, the focal lengths of the first lens group and the second lens group satisfy the following conditional expression:

[0047] 0.25<|f1 / f2|≤0.28

[0048] 0.8<|f1 / f0|<1.1

[0049] 2.5<|f2 / f0|<4.3

[0050] Wherein f1 represents the focal length of the first lens group 1, f2 represents the focal length of the second lens group 2, and f0 represents the focal length of the entire lens.

[0051] In Examples 1-3, the focal length of the first lens 11 ranges from 48.5 to 74.4 mm, the focal length of the second lens 12 ranges from 46.3 to 58.7 mm, the focal length of the third lens 12 ranges from -25.3 to -24.4 mm, the focal length of the fourth lens 15 ranges from -12.0 to -11.5 mm, the focal length of the fifth lens 16 ranges from 14.0 to 14.2 mm, the focal length of the sixth lens 17 ranges from 19.4 to 20.5 mm, the focal length of the seventh lens 18 ranges from -31.5 to -31.2 mm, the focal length of the eighth lens 21 ranges from 39.5 to 40.0 mm, and the focal length of the ninth lens 22 ranges from -50.3 to -49.3 mm.

[0052] The following further describes a specific embodiment of a large-target-area half-group mobile industrial macro lens applicable to the above-mentioned implementation mode with reference to the accompanying drawings.

[0053] Example 1

[0054] like Figure 1 As shown, the large target surface half-group mobile industrial macro lens provided in this embodiment has a first lens group 1 that can move forward and backward along the optical axis, a fixed second lens group 2, and a protective glass 3 arranged in sequence from the object side to the image side along the optical axis. The optical data of the lens of this embodiment are shown in Table 1 below. The surface number in Table 1 refers to the numbering of each surface from the object side of the first lens to the image side of the protective glass along the optical axis from the object plane to the image plane. Table 1 also includes: the radius of curvature R of each surface, the thickness of each lens or the distance d between two adjacent surfaces, the refractive index n of each lens, the focal length f of each lens, and the combined focal length of the lens group.

[0055] Table 1 Optical data of industrial macro lens provided in Example 1

[0056]

[0057]

[0058] In this embodiment, the focal lengths of the first lens group and the second lens group satisfy the following conditional formula:

[0059] |f1 / f2|=0.28

[0060] 0.85<|f1 / f0|<1.10

[0061] 2.56<|f2 / f0|<3.94

[0062] Wherein f1 represents the focal length of the first lens group 1, f2 represents the focal length of the second lens group 2, and f0 represents the focal length of the entire lens. The distance d1 between the image side of the seventh lens 18 of the first lens group 1 and the object side of the eighth lens 21 of the second lens group 2 satisfies the following formula 5.8mm≤d1≤59.2mm, the working distance range of the lens is 85.0~238.9mm, and the maximum image circle diameter of the large target surface half-group mobile industrial macro lens provided in this embodiment on the image plane 4 is equal to 29.0mm.

[0063] Three representative magnifications are selected for image quality analysis. The MTF curves at different magnifications of this embodiment are as follows: Figure 2-4 As shown, Figure 2 As shown, the MTF at 140 line pairs / mm is greater than 0.19 when the magnification is 0.25×. Figure 3 As shown, the MTF at 140 line pairs / mm is greater than 0.17 when the magnification is 0.5×. Figure 4 As shown, when the magnification is 1×, the MTF at 140 line pairs / mm is greater than 0.15. It can be seen that the large-target surface half-group mobile industrial macro lens provided in Example 1 has a high contrast and can achieve good imaging quality.

[0064] Example 2

[0065] like Figure 5 As shown, the large-target-surface half-group mobile industrial macro lens provided in this embodiment has a first lens group 1 that can move forward and backward along the optical axis, a fixed second lens group 2, and a protective glass 3 arranged in sequence from the object side to the image side along the optical axis. The optical data of the lens of this embodiment are shown in Table 2 below. The surface numbers in Table 2 refer to the numbers of each surface from the object side of the first lens to the image side of the protective glass along the optical axis from the object plane to the image plane. Table 2 also includes: the radius of curvature R of each surface, the thickness of each lens and the distance d between two adjacent surfaces, the refractive index n of each lens, the focal length f of each lens, and the combined focal length of the lens group.

[0066] Table 2 Optical data of industrial macro lens provided in Example 2

[0067]

[0068]

[0069] In this embodiment, the focal lengths of the first lens group and the second lens group satisfy the following conditional formula:

[0070] |f1 / f2|=0.26

[0071] 0.87<|f1 / f0|<1.10

[0072] 3.38<|f2 / f0|<4.25

[0073] Where f1 represents the focal length of the first lens group 1, f2 represents the focal length of the second lens group 2, and f0 represents the focal length of the entire lens. The distance d1 between the image side of the seventh lens 18 of the first lens group 1 and the object side of the eighth lens 21 of the second lens group 2 satisfies the following formula 5.0mm≤d1≤58.0mm, the working distance range of the lens is 90.0~244.9mm, and the maximum image circle diameter of the large target surface half-group mobile industrial macro lens on the image plane 4 is equal to 29.0mm.

[0074] Three representative magnifications are selected for image quality analysis. The MTF curves at different magnifications of this embodiment are as follows: Figure 6-8 As shown, Figure 6 As shown, the MTF at 140 line pairs / mm is greater than 0.26 when the magnification is 0.25×. Figure 7 As shown, the MTF at 140 line pairs / mm is greater than 0.24 when the magnification is 0.5×. Figure 8 As shown, when the magnification is 1×, the MTF at 140 line pairs / mm is greater than 0.18. It can be seen that the large-target surface half-group mobile industrial macro lens provided in Example 2 has a high contrast and can achieve good imaging quality.

[0075] Example 3

[0076] like Fig. 9 As shown, the large target surface half-group mobile industrial macro lens provided in this embodiment has a first lens group 1 that can move forward and backward along the optical axis, a fixed second lens group 2, and a protective glass 3 arranged in sequence from the object side to the image side along the optical axis. The optical data of the lens of this embodiment are shown in Table 3 below. The surface number in Table 3 refers to the numbering of each surface from the object side of the first lens to the image side of the protective glass along the optical axis from the object plane to the image plane. Table 3 also includes: the radius of curvature R of each surface, the thickness of each lens and the distance d between two adjacent surfaces, the refractive index n of each lens, the focal length f of each lens, and the combined focal length of the lens group.

[0077] Table 3 Optical data of industrial macro lens provided in Example 3

[0078]

[0079] In this embodiment, the focal lengths of the first lens group and the second lens group satisfy the following conditional formula:

[0080] |f1 / f2|=0.27

[0081] 0.86<|f1 / f0|<1.08

[0082] 3.22<|f2 / f0|<4.04

[0083] Wherein f1 represents the focal length of the first lens group 1, f2 represents the focal length of the second lens group 2, and f0 represents the focal length of the entire lens. The distance d1 between the image side of the seventh lens 18 of the first lens group 1 and the object side of the eighth lens 21 of the second lens group 2 satisfies the following formula 5.9mm≤d1≤59.0mm, the working distance range of the lens is 85.3~239.8mm, and the maximum image circle diameter of the large target surface half-group mobile industrial macro lens on the image plane 4 is equal to 29.0mm.

[0084] Three representative magnifications are selected for image quality analysis. The MTF curves at different magnifications of this embodiment are as follows: Figure 10-12 As shown, Fig.10 As shown, the MTF at 140 line pairs / mm is greater than 0.26 when the magnification is 0.25×. Fig.11 As shown, the MTF at 140 line pairs / mm is greater than 0.25 when the magnification is 0.5×. Fig.12 As shown, when the magnification is 1×, the MTF at 140 line pairs / mm is greater than 0.20. It can be seen that the large-target surface half-group mobile industrial macro lens provided in Example 3 has a high contrast and can achieve good imaging quality.

[0085] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A large-surface half-group mobile industrial macro lens, characterized in that: A first lens group that can move forward and backward along the optical axis, a fixed second lens group and a protective glass are arranged in sequence from the object side to the image side along the optical axis, and a variable diaphragm that moves with the first lens group is arranged in the first lens group; The first lens group moves forward and backward along the optical axis, so that the distance between the first lens group and the second lens group can be adjusted to achieve continuous magnification change; The variable aperture moves along with the first lens group during the continuous zoom process; The first lens group includes: a first lens having a convex surface on the object side and a flat surface on the image side, a second lens having a convex surface on the object side and a concave surface on the image side, a third lens having a convex surface on the object side and a concave surface on the image side, a fourth lens having a concave surface on the object side and a concave surface on the image side, a fifth lens having a convex surface on the object side and a convex surface on the image side, a sixth lens having a flat surface on the object side and a convex surface on the image side, and a seventh lens having a concave surface on the object side and a convex surface on the image side; The concave surface of the fourth lens and the convex surface of the fifth lens are glued together to form a first glued lens, and the fourth lens is close to the object plane. The convex surface of the sixth lens and the concave surface of the seventh lens are glued together to form a second glued lens, and the sixth lens is close to the object plane. The second lens group includes an eighth lens and a ninth lens, and the eighth lens is close to the object plane; The object side of the eighth lens is concave and the image side is convex. The object side of the ninth lens is concave and the image side is convex. The convex surface of the eighth lens and the concave surface of the ninth lens are cemented to form a third cemented lens.

2. The large-target-area half-group mobile industrial macro lens according to claim 1, characterized in that: The focal lengths of the first lens group and the second lens group satisfy the following conditional equation: 0.1<|f1 / f2|<0.5 0.5<|f1 / f0|<1.5 2.0<|f2 / f0|<5.0 Where f1 represents the focal length of the first lens group, f2 represents the focal length of the second lens group, and f0 represents the focal length of the entire lens.

3. The large-target-area half-group mobile industrial macro lens according to claim 1, characterized in that: The focal lengths of the first lens group and the second lens group satisfy the following conditional equation: 0.25<|f1 / f2|≤0.28 0.8<|f1 / f0|<1.1 2.5<|f2 / f0|<4.3 Where f1 represents the focal length of the first lens group, f2 represents the focal length of the second lens group, and f0 represents the focal length of the entire lens.

4. The large-target-surface half-group mobile industrial macro lens according to claim 1, characterized in that: The variable iris is arranged between the third lens and the fourth lens of the first lens group, and the aperture size of the variable iris is adjustable.

5. The large-target-area half-group mobile industrial macro lens according to claim 1, characterized in that: The focal length of the first lens ranges from 40.0 to 80.0 mm, the focal length of the second lens ranges from 40.0 to 60.0 mm, the focal length of the third lens ranges from -30.0 to -20.0 mm, the focal length of the fourth lens ranges from -5.0 to -15.0 mm, the focal length of the fifth lens ranges from 10.0 to 20.0 mm, the focal length of the sixth lens ranges from 15.0 to 25.0 mm, the focal length of the seventh lens ranges from -40.0 to -20.0 mm, the focal length of the eighth lens ranges from 30.0 to 45.0 mm, and the focal length of the ninth lens ranges from -55.0 to -45.0 mm.

6. The large-target-area half-group mobile industrial macro lens according to claim 1, characterized in that: The focal length of the first lens ranges from 48.5 to 74.4 mm, the focal length of the second lens ranges from 46.3 to 58.7 mm, the focal length of the third lens ranges from -25.3 to -24.4 mm, the focal length of the fourth lens ranges from -12.0 to -11.5 mm, the focal length of the fifth lens ranges from 14.0 to 14.2 mm, the focal length of the sixth lens ranges from 19.4 to 20.5 mm, the focal length of the seventh lens ranges from -31.5 to -31.2 mm, the focal length of the eighth lens ranges from 39.5 to 40.0 mm, and the focal length of the ninth lens ranges from -50.3 to -49.3 mm.

7. The large-target-area half-group mobile industrial macro lens according to claim 1, characterized in that: A distance d1 between the image side of the first lens group and the object side of the second lens group satisfies the following formula: 5.0 mm ≤ d1 ≤ 60.0 mm.

8. The large-target-surface half-group mobile industrial macro lens according to any one of claims 1 to 7, characterized in that: The industrial macro lens has a working distance of 80.0 to 250.0 mm and a magnification of 0.2x to 1.0x.

9. The large-target-surface half-group mobile industrial macro lens according to any one of claims 1 to 7, characterized in that: The maximum imaging circle diameter of the industrial macro lens is greater than 29 mm, matching a 1.75-inch image sensor.

Images