A long focal industrial zoom lens

Abstract

The application discloses a long-focus industrial zoom lens, and relates to the technical field of machine vision devices, which comprises, in sequence from an image plane to an object plane along an optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens; the focal lengths of the first lens and the second lens, the third lens and the fourth lens, the fifth lens and the sixth lens, the seventh lens and the eighth lens are negative, positive, positive, negative, positive, positive, positive, positive and negative in sequence; the first lens group, the third lens group and the fourth lens group are configured to be movable along the optical axis, focusing is realized through the movement of the first lens, and the magnification change is realized through the movement of the third lens group and the fourth lens group. The application adopts the mutual compensation of positive and negative lens optical powers, not only ensures the performance of the optical system, but also reduces the processing cost, simplifies the structure, reduces the weight, improves the picture image quality while using low-dispersion materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of machine vision devices, and particularly relates to a long-focus industrial zoom lens. BACKGROUND

[0002] Under the background of deep integration of mechanization and intelligence, the machine vision system continues to innovate and upgrade, and increasingly pursues the comprehensive performance of "seeing clearly, miniaturization" to meet the consumer demand of emerging application scenarios such as Internet of Things and 5G big data. During the operation of the equipment, not only the accurate image capture and magnification need to be realized, but also the network connection and real-time data acquisition capability often need to be possessed, which puts forward higher requirements for the adaptability of the lens under different working distances and complex scenes. Traditional measuring instruments, electronic magnifying glasses, medical microscopes and machine vision lenses all face new challenges.

[0003] However, most of the lens products on the market still have problems such as insufficient clarity and not being specially optimized for actual application scenarios. Traditional optical design often increases the target size to realize basic optical performance, which makes it difficult to balance optical precision and structural compactness, not only causing large size, but also significantly increasing manufacturing cost. SUMMARY

[0004] The purpose of the present application is to provide a long-focus industrial zoom lens to solve the problem that the traditional optical design often increases the target size to realize basic optical performance, which makes it difficult to balance optical precision and structural compactness, not only causing large size, but also significantly increasing manufacturing cost.

[0005] To achieve the above purpose, the present application provides the following technical scheme:

[0006] A long-focus industrial zoom lens comprises, in order along the optical axis from the image plane to the object plane:

[0007] A first lens group comprises, in order, a first lens and a second lens, and the first lens and the second lens are cemented together;

[0008] A second lens group comprises, in order, a third lens and a fourth lens, and the third lens and the fourth lens are cemented together;

[0009] A third lens group comprises, in order, a fifth lens and a sixth lens, and the fifth lens and the sixth lens are cemented together;

[0010] A fourth lens group comprises, in order, a seventh lens and an eighth lens, and the seventh lens and the eighth lens are cemented together;

[0011] A ninth lens;

[0012] The focal lengths of the first lens and the second lens, the third lens and the fourth lens, the fifth lens and the sixth lens, the seventh lens and the eighth lens are negative, positive, positive, negative, positive, positive, positive, negative and positive in sequence.

[0013] The first lens group, the third lens group and the fourth lens group are configured to be movable along the optical axis, the second lens group and the ninth lens are fixedly arranged, focusing is achieved by moving the first lens group, and the magnification change is achieved by moving the third lens group and the fourth lens group.

[0014] In the preferred technical solution, the range of the magnification change is 0.7 times to 2.8 times.

[0015] In the preferred technical solution, the first lens group is composed of a first lens with positive focal length and a second lens with negative focal length.

[0016] In the preferred technical solution, the second lens group is composed of a third lens with positive focal length and a fourth lens with negative focal length.

[0017] In the preferred technical solution, the third lens group is composed of a fifth lens with negative focal length and a sixth lens with positive focal length.

[0018] In the preferred technical solution, the fourth lens group is composed of a seventh lens with negative focal length and an eighth lens with positive focal length.

[0019] In the preferred technical solution, a half-transmission half-reflection filter is further arranged between the first lens group and the second lens group, and one side of the half-transmission half-reflection filter is provided with an illumination lens.

[0020] In the preferred technical solution, the first lens group, the second lens group, the third lens group, the fourth lens group, the ninth lens, the half-transmission half-reflection filter and the illumination lens are all arranged in the interior of a lens barrel, the optical axis of the illumination lens is perpendicular to the optical axes of the first lens group, the second lens group, the third lens group and the fourth lens group, and the half-transmission half-reflection filter is arranged obliquely.

[0021] In the preferred technical solution, one side of the illumination lens is a plane, and the other side is a spherical surface.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] The present application realizes high-definition imaging, and clear images can be obtained in the entire zoom range of 0.7 times to 2.8 times. The lens structure is compact, the target surface size is 2 / 3 inch, and the advantages of small volume and high-definition imaging are combined, the miniaturization of the entire system is realized, and the sharpness of the center and the edge region is nearly consistent on the entire image surface.

[0024] The optical lens is a zoom lens, the focal length is 135-140, the F# is 7-20, the target surface is 2 / 3, the total optical length is 300-320, the coaxial light is ensured when the light source is added, and high resolution is also ensured; the positive and negative lens power is used for mutual compensation, which not only ensures the performance of the optical system, but also reduces the processing cost, simplifies the structure, reduces the weight, is beneficial to mass production, meets the market demand, and improves the picture image quality while using low dispersion materials. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used for the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained according to these drawings without creative labor for those skilled in the art.

[0026] Figure 1 It is a structural schematic diagram of the present application;

[0027] Figure 2 It is a lens group matching structure schematic diagram of the present application;

[0028] Figure 3 It is a modulation transfer function (MTF) curve diagram of the present application;

[0029] Figure 4 It is an out-of-focus MTF curve diagram of the present application;

[0030] Figure 5 It is a point column diagram of the present application;

[0031] Figure 6 It is a relative luminance curve diagram of the present application;

[0032] Figure 7 It is a vertical axis chromatic aberration curve diagram of the present application;

[0033] Figure 8 It is a mirror surface, object surface and image surface schematic diagram of the present application;

[0034] The figure mark annotation: 1-first lens group, 2-second lens group, 3-third lens group, 4-fourth lens group, 5-lens barrel, G1-first lens, G2-second lens, G3-third lens, G4-fourth lens, G5-fifth lens, G6-sixth lens, G7-seventh lens, G8-eighth lens, G9-ninth lens, G10-semi-transparent semi-reflection filter, G11-illumination lens. DETAILED DESCRIPTION

[0035] The present application will be described in detail below with reference to the accompanying drawings. In the drawings or description, similar or identical parts are designated by the same reference numerals, and in practical applications, the shape, thickness, or height of each component can be enlarged or reduced. The embodiments listed in the present application are only used to illustrate the present application and are not intended to limit the scope of the present application. Any obvious modification or change made to the present application does not deviate from the spirit and scope of the present application.

[0036] As shown in Figure 1 and Figure 2 , a long-focus industrial zoom lens includes, in order along the optical axis from the image plane to the object plane:

[0037] A first lens group 1 includes, in order, a first lens G1 and a second lens G2, the first lens G1 and the second lens G2 being cemented together; a second lens group 2 includes, in order, a third lens G3 and a fourth lens G4, the third lens G3 and the fourth lens G4 being cemented together; a third lens group 3 includes, in order, a fifth lens G5 and a sixth lens G6, the fifth lens G5 and the sixth lens G6 being cemented together; a fourth lens group 4 includes, in order, a seventh lens G7 and an eighth lens G8, the seventh lens G7 and the eighth lens G8 being cemented together; and a ninth lens G9.

[0038] The focal lengths of the first lens G1 and the second lens G2 being cemented together, the third lens G3 and the fourth lens G4 being cemented together, the fifth lens G5 and the sixth lens G6 being cemented together, the seventh lens G7 and the eighth lens G8 being cemented together are, in order, negative, positive, positive, negative, positive, positive, positive, positive, and negative.

[0039] Among them, the first lens group 1, the third lens group 3, and the fourth lens group 4 are configured to be movable along the optical axis, the second lens group 2 and the ninth lens G9 are fixedly arranged, focusing is achieved by movement of the first lens group 1, and magnification change is achieved by movement of the third lens group 3 and the fourth lens group 4, the range of magnification change being 0.7 times to 2.8 times.

[0040] The first lens group 1 is composed of a first lens G1 with positive refractive power and a second lens G2 with negative refractive power. The second lens group 2 is composed of a third lens G3 with positive refractive power and a fourth lens G4 with negative refractive power. The third lens group 3 is composed of a fifth lens G5 with negative refractive power and a sixth lens G6 with positive refractive power. The fourth lens group 4 is composed of a seventh lens G7 with negative refractive power and an eighth lens G8 with positive refractive power.

[0041] Also include a half-transmission half-reflection filter G10, which is arranged between the first lens group 1 and the second lens group 2, one side of the half-transmission half-reflection filter G10 is provided with an illumination lens G11. The first lens group 1, the second lens group 2, the third lens group 3, the fourth lens group 4, the ninth lens G9, the half-transmission half-reflection filter G10 and the illumination lens G11 are all arranged inside the lens barrel 5, the optical axis of the illumination lens G11 is perpendicular to the optical axis of the first lens group 1, the second lens group 2, the third lens group 3 and the fourth lens group 4, the half-transmission half-reflection filter G10 is arranged obliquely, the light source is reflected on the half-transmission half-reflection filter G10 through the illumination lens G11, and then forms a light spot on the object plane through the imaging lens, so as to realize the illumination effect; the half-transmission half-reflection filter G10 is used to reflect part of the light source to the imaging surface, so as to realize the combination of imaging and illumination. One side of the illumination lens G11 is a plane (close to the light source), and the other side is a spherical surface, so as to optimize the reflection and transmission efficiency of light.

[0042] The fifth lens G5 and the sixth lens G6 are cemented, and the seventh lens G7 and the eighth lens G8 are cemented.

[0043] The third lens G3 and the eighth lens G8 adopt low-dispersion materials, which significantly improve the imaging effect. Meanwhile, the first lens G1 and the second lens G2, the third lens G3 and the fourth lens G4, the fifth lens G5 and the sixth lens G6, and the seventh lens G7 and the eighth lens G8 adopt cemented glass, and the fifth lens G5, the sixth lens G6 and the seventh lens G7 adopt high-refractive materials.

[0044] The combination of multiple lenses and cemented lenses lengthens the air gap of the lenses, realizes clear image quality, and improves the image quality by matching low-refractive and low-dispersion glass to eliminate chromatic aberration. The combination of the seventh lens G7 and the eighth lens G8 ensures the imaging effect and balances the spherical aberration, coma, on-axis chromatic aberration and off-axis chromatic aberration. The combination of one negative lens and one positive lens significantly improves the imaging effect.

[0045] As shown in Figure 3 , the traditional lens mtf design is determined to be ok at 0.1 line pairs, and the lens of the present application can reach 100 line pairs or more than 0.2, which shows that the imaging of the lens is higher than that of the traditional lens. Figure 4 As shown in Figure 5 , the size of the pixel points corresponding to the lens of the present application is matched with the wafer. Figure 6 As shown in Figure 7 , the color of the shot of the lens of the present application is good.

[0046] This invention uses an industrial machine vision lens, specifically in the 400-700nm wavelength range. The design is tailored to specific needs, featuring a wide wavelength range to reduce costs. It also incorporates low distortion at small angles, resulting in vignetting. Furthermore, the structure incorporates a chamfering mechanism to improve lens flatness, further enhancing image quality. This invention can optionally employ a temperature compensation design, allowing it to operate without defocusing in environments ranging from -40℃ to +80℃.

[0047] Table 1: Data Sheet of the Imaging System of the Invention

[0048]

[0049] Table 2: Lighting System Data Sheet of the Invention

[0050]

[0051] like Figure 8 As shown in Tables 1 and 2, S1 is the outer mirror surface of the first lens G1, S3 is the outer mirror surface of the second lens G2, and S2 is the cemented surface between the first lens G1 and the second lens G2; S4 is the outer mirror surface of the third lens G3, S6 is the outer mirror surface of the fourth lens G4, and S5 is the cemented surface between the third lens G3 and the fourth lens G4; S7 is the outer mirror surface of the fifth lens G5, S9 is the outer mirror surface of the sixth lens G6, and S8 is the cemented surface between the fifth lens G5 and the sixth lens G6; S10 ... second lens G1. The top surface; S11 is the outer mirror surface of the seventh lens G7, S13 is the outer mirror surface of the eighth lens G8, S12 is the cemented surface between the seventh lens G7 and the eighth lens G8; S14 is the mirror surface of the ninth lens G9; S15 is the image plane; S16 is the inner spherical surface of the illumination lens G11; S17 is the outer plane of the illumination lens G11; OBJ in the imaging system refers to the object plane of the imaging system, and OBJ in the illumination system refers to the object plane of the illumination system (the side of the semi-transparent and semi-reflective filter G10 closest to the object side).

[0052] As can be seen from the data in Tables 1 and 2, this invention achieves high-level correction of various aberrations by selecting specific combinations of low-dispersion (high vd) and high-refractive-index (high nd) materials (such as G3, G8; G5, G6, G7) and multiple cementitious groups (G1 / G2, G3 / G4, G5 / G6, G7 / G8). This ensures the achievement of key performance indicators such as a focal length of 135-140mm, an f / s 7-20 aperture, a 2 / 3″ target surface, and a total length of 300-320mm.

[0053] Furthermore, it should be understood that although the specification is described in terms of embodiments, not every embodiment includes every feature or implementation described herein. The specification can include implicit combinations of explicitly mentioned features and / or implicit combinations of implicitly mentioned features. Such combinations are also expressly included within the scope of the specification and an embodiment.

Claims

1. A long focal length industrial zoom lens characterized by, Comprise successively along the optical axis from the image plane to the object plane: A first lens group (1) comprising successively a first lens (G1), a second lens (G2), the first lens (G1) and the second lens (G2) being cemented together; A second lens group (2) comprising successively a third lens (G3), a fourth lens (G4), the third lens (G3) and the fourth lens (G4) being cemented together; A third lens group (3) comprising successively a fifth lens (G5), a sixth lens (G6), the fifth lens (G5) and the sixth lens (G6) being cemented together; A fourth lens group (4) comprising successively a seventh lens (G7), an eighth lens (G8), the seventh lens (G7) and the eighth lens (G8) being cemented together; A ninth lens (G9); The first lens (G1) and the second lens (G2) being cemented together, the third lens (G3) and the fourth lens (G4) being cemented together, the fifth lens (G5) and the sixth lens (G6) being cemented together, the seventh lens (G7) and the eighth lens (G8) being cemented together, the focal lengths of the first lens (G1), the second lens (G2), the third lens (G3), the fourth lens (G4), the fifth lens (G5), the sixth lens (G6), the seventh lens (G7), the eighth lens (G8) and the ninth lens (G9) being negative, positive, positive, negative, positive, positive, positive, positive and negative successively; Wherein, the first lens group (1), the third lens group (3) and the fourth lens group (4) are configured to be movable along the optical axis, the second lens group (2) and the ninth lens (G9) are fixedly arranged, focusing is performed by moving the first lens group (1), and magnification change is realized by moving the third lens group (3) and the fourth lens group (4); The range of magnification change is 0.7 times to 2.8 times; Further comprising a half-transmission half-reflection filter (G10) arranged between the first lens group (1) and the second lens group (2), one side of the half-transmission half-reflection filter (G10) being provided with an illumination lens (G11).

2. The tele industrial zoom lens according to claim 1, characterized by, The first lens group (1), the second lens group (2), the third lens group (3), the fourth lens group (4), the ninth lens (G9), the half-transmission half-reflection filter (G10) and the illumination lens (G11) are all arranged inside a lens barrel (5), the optical axis of the illumination lens (G11) is perpendicular to the optical axes of the first lens group (1), the second lens group (2), the third lens group (3) and the fourth lens group (4), and the half-transmission half-reflection filter (G10) is arranged obliquely.

3. The tele industrial zoom lens according to claim 1, characterized by, One side of the illumination lens (G11) is a plane, and the other side is a spherical surface.

4. The tele industrial zoom lens according to claim 2, characterized by, A diaphragm is arranged between the fifth lens (G5) and the sixth lens (G6) which are cemented together, and between the seventh lens (G7) and the eighth lens (G8) which are cemented together.

Images