A long working distance zoom lens

Abstract

The utility model discloses a long working distance zoom lens, comprising a first lens, a second lens, a third lens, a fourth lens and a fifth lens distributed in sequence from the object plane side to the image plane side along the optical axis, the second lens is glued to the third lens, and the fourth lens is glued to the fifth lens; the long working distance zoom lens provided by the utility model has the characteristics of simple structure and high zoom ratio, and by setting and matching the parameters of the five lenses, the zoom lens has a high zoom ratio and a simple structure, and can meet the use requirements of cameras with a size of 2 / 3 or less.

Description

Technical Field

[0001] The utility model relates to the technical field of optical lenses, in particular to a variable magnification lens with a long working distance. Background Art

[0002] Zoom industrial lenses are optics designed specifically for industrial applications that require variable focal length and magnification capabilities. These lenses can flexibly adjust magnification and focus settings, allowing users to capture detailed images of objects at different distances. Zoom industrial lenses are often used in machine vision systems, surveillance cameras, and other industrial imaging applications where precise and adaptive optics are critical. These lenses play a vital role in improving image quality, increasing inspection accuracy, and monitoring processes in a variety of industrial environments. The adjustable magnification of zoom industrial lenses helps improve versatility and efficiency in capturing high-quality images at different working distances and different magnifications.

[0003] Achieving consistent image quality across the entire zoom range of a zoom lens can be challenging. Maintaining clarity, minimizing distortion, and controlling aberrations across the entire magnification range requires sophisticated optical design and high-quality lens elements, which are inherently more complex than fixed-magnification lenses, which typically involve multiple lens elements and complex optical designs. This complexity can lead to increased manufacturing costs, potential mechanical failures, and challenges with calibration.

[0004] Therefore, how to achieve a larger zoom ratio with a relatively simple structure has become a technical problem that needs to be solved urgently in this field. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a long working distance zoom lens which can realize a higher zoom ratio with a simple structure.

[0006] In order to solve the above technical problems, the technical solution adopted by the utility model is: a long working distance zoom lens, comprising a first lens, a second lens, a third lens, a fourth lens and a fifth lens distributed in sequence from the object plane side to the image plane side along the optical axis, the second lens is glued to the third lens, and the fourth lens is glued to the fifth lens; the surface curvature radius of the first lens facing the object plane is 88mm±2mm, the surface curvature radius of the first lens facing the image plane is -74mm±2mm, the refractive index of the first lens is 1.5, the dispersion coefficient is 81.6, the effective aperture is 40mm±1mm, and the center thickness is 8mm±0.2mm; the surface curvature radius of the second lens facing the object plane is 38mm±2mm, the surface curvature radius of the second lens facing the image plane is -63mm±2mm, the refractive index of the second lens is 1.5, the dispersion coefficient is 81.6, the effective aperture is 34mm±1mm, and the center thickness is 8mm±0.2mm; The surface curvature radius of the three lenses facing the object plane is -63mm±2mm, the surface curvature radius of the third lens facing the image plane is 72mm±2mm, the refractive index of the third lens is 1.8, the dispersion coefficient is 42.3, the effective aperture is 34mm±1mm, and the center thickness is 6mm±0.2mm; the surface curvature radius of the fourth lens facing the object plane is 7900mm±2mm, and the surface curvature radius of the fourth lens facing the image plane is -26mm±2 mm, the refractive index of the fourth lens is 1.73, the dispersion coefficient is 40.3, the effective aperture is 26mm±1mm, and the center thickness is 9mm±0.2mm; the surface curvature radius of the fifth lens facing the object plane is -26mm±2mm, the surface curvature radius of the fifth lens facing the image plane is 25mm±2mm, the refractive index of the fifth lens is 1.65, the dispersion coefficient is 34, the effective aperture is 26mm±1mm, and the center thickness is 9mm±0.2mm.

[0007] Furthermore, the total focal length of the zoom lens is f, and the combined focal length of the first lens, the second lens and the third lens is f 1 , the combined focal length of the fourth lens and the fifth lens is f 2 , then the formula is satisfied: 0.5<|f 1 / f|<0.7; 0.25<|f 2 / f|<0.4.

[0008] Furthermore, the distance between the object plane and the first lens is 819 mm, the distance between the first lens and the second lens is 2 mm, the distance between the third lens and the fourth lens is 15.6 mm, and the distance between the fifth lens and the image plane is 111 mm.

[0009] Furthermore, the distance between the object plane and the first lens is 550 mm, the distance between the first lens and the second lens is 3.2 mm, the distance between the third lens and the fourth lens is 18.2 mm, and the distance between the fifth lens and the image plane is 122 mm.

[0010] Furthermore, the distance between the object plane and the first lens is 400 mm, the distance between the first lens and the second lens is 4.6 mm, the distance between the third lens and the fourth lens is 21.6 mm, and the distance between the fifth lens and the image plane is 138 mm.

[0011] The beneficial effect of the utility model is that the long working distance zoom lens provided by the utility model has the characteristics of simple structure and high zoom ratio. By setting and matching the parameters of the five lenses, the zoom lens has a high zoom ratio and a simple structure, and can meet the use requirements of cameras of size 2 / 3 and below. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic structural diagram of a long working distance zoom lens of the utility model;

[0013] Figure 2 This is a diffraction MTF modulation function diagram of the long working distance zoom lens of the first embodiment of the utility model;

[0014] Figure 3 This is a distortion diagram of the long working distance zoom lens of the first embodiment of the utility model;

[0015] Figure 4 This is a diffraction MTF modulation function diagram of the long working distance zoom lens of the first embodiment of the utility model;

[0016] Figure 5 This is a distortion diagram of the long working distance zoom lens of the first embodiment of the utility model;

[0017] Figure 6 This is a diffraction MTF modulation function diagram of the long working distance zoom lens of the first embodiment of the utility model;

[0018] Figure 7 This is a distortion diagram of the long working distance zoom lens of the first embodiment of the utility model.

[0019] Description of labels:

[0020] 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Optical axis. DETAILED DESCRIPTION

[0021] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes and the accompanying drawings.

[0022] Please refer to Figures 1 to 3 , Embodiment 1 of the utility model is: a long working distance zoom lens, comprising a first lens 1, a second lens 2, a third lens 3, a fourth lens 4 and a fifth lens 5, which are sequentially distributed from the object plane side to the image plane side along the optical axis 6, the second lens 2 is glued to the third lens 3, and the fourth lens 4 is glued to the fifth lens 5; the surface curvature radius of the first lens 1 facing the object plane is 88mm±2mm, the surface curvature radius of the first lens 1 facing the image plane is -74mm±2mm, the The refractive index of the first lens 1 is 1.5, the dispersion coefficient is 81.6, the effective aperture is 40mm±1mm, and the center thickness is 8mm±0.2mm; the surface curvature radius of the second lens 2 facing the object plane is 38mm±2mm, the surface curvature radius of the second lens 2 facing the image plane is -63mm±2mm, the refractive index of the second lens 2 is 1.5, the dispersion coefficient is 81.6, the effective aperture is 34mm±1mm, and the center thickness is 8mm±0.2mm; the third lens The surface curvature radius of the side of the lens 3 facing the object plane is -63mm±2mm, the surface curvature radius of the side of the third lens 3 facing the image plane is 72mm±2mm, the refractive index of the third lens 3 is 1.8, the dispersion coefficient is 42.3, the effective aperture is 34mm±1mm, and the center thickness is 6mm±0.2mm; the surface curvature radius of the side of the fourth lens 4 facing the object plane is 7900mm±2mm, and the surface curvature radius of the side of the fourth lens 4 facing the image plane is -26mm±2 mm, the refractive index of the fourth lens 4 is 1.73, the dispersion coefficient is 40.3, the effective aperture is 26mm±1mm, and the center thickness is 9mm±0.2mm; the surface curvature radius of the fifth lens 5 facing the object plane is -26mm±2mm, the surface curvature radius of the fifth lens 5 facing the image plane is 25mm±2mm, the refractive index of the fifth lens 5 is 1.65, the dispersion coefficient is 34, the effective aperture is 26mm±1mm, and the center thickness is 9mm±0.2mm.

[0023] Preferably, the total focal length of the zoom lens is f, the combined focal length of the first lens 1, the second lens 2 and the third lens 3 is f1, and the combined focal length of the fourth lens 4 and the fifth lens 5 is f2, then the formula is satisfied: 0.5<|f1 / f|<0.7; 0.25<|f2 / f|<0.4.

[0024] In this embodiment, the distance between the object plane and the first lens 1 is 819 mm, the distance between the first lens 1 and the second lens 2 is 2 mm, the distance between the third lens 3 and the fourth lens 4 is 15.6 mm, and the distance between the fifth lens 5 and the image plane is 111 mm. Specifically, through the above parameter settings, the aperture size F number of this long working distance zoom lens is 8, the magnification is 0.3X, the lens focal length is 160 mm, and it matches cameras with a target surface size of 2 / 3 inches or less.

[0025] Embodiment 2

[0026] Please refer to Figure 1 , Figure 4 and Figure 5 In this embodiment, the distance between the object plane and the first lens 1 is 550 mm, the distance between the first lens 1 and the second lens 2 is 3.2 mm, the distance between the third lens 3 and the fourth lens 4 is 18.2 mm, and the distance between the fifth lens 5 and the image plane is 122 mm. Specifically, through the above parameter settings, the aperture size F number of this long working distance zoom lens is 8, the magnification is 0.5X, the lens focal length is 140 mm, and it matches the camera with a target surface size of 2 / 3 inch or less.

[0027] Embodiment 3

[0028] Please refer to Figure 1 , Figure 6 and Figure 7 In this embodiment, the distance between the object plane and the first lens 1 is 400 mm, the distance between the first lens 1 and the second lens 2 is 4.6 mm, the distance between the third lens 3 and the fourth lens 4 is 21.6 mm, and the distance between the fifth lens 5 and the image plane is 138 mm. Specifically, through the above parameter settings, the aperture size F number of this long working distance zoom lens is 8, the magnification is 0.8X, the lens focal length is 125 mm, and it matches the camera with a target surface size of 2 / 3 inch or less.

[0029] To sum up, the long working distance zoom lens provided by the utility model has the characteristics of simple structure and high zoom ratio. By setting and matching the parameters of the five lenses, the zoom lens has a high zoom ratio and a simple structure, which can meet the use requirements of cameras of size 2 / 3 and below.

[0030] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent transformations made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in the relevant technical field, are also included in the patent protection scope of the present invention.

Claims

1. A long working distance zoom lens, characterized in that: The invention comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens, which are sequentially distributed from the object plane side to the image plane side along the optical axis, the second lens is glued to the third lens, and the fourth lens is glued to the fifth lens; the surface curvature radius of the first lens facing the object plane is 88mm±2mm, the surface curvature radius of the first lens facing the image plane is -74mm±2mm, the refractive index of the first lens is 1.5, the dispersion coefficient is 81.6, the effective aperture is 40mm±1mm, and the center thickness is 8mm±0.2mm; the surface curvature radius of the second lens facing the object plane is 38mm±2mm, the surface curvature radius of the second lens facing the image plane is -63mm±2mm, the refractive index of the second lens is 1.5, the dispersion coefficient is 81.6, the effective aperture is 34mm±1mm, and the center thickness is 8mm±0.2mm; the surface curvature radius of the third lens facing the object plane is ﹣63mm±2mm, the surface curvature radius of the third lens facing the image plane is 72mm±2mm, the refractive index of the third lens is 1.8, the dispersion coefficient is 42.3, the effective aperture is 34mm±1mm, and the center thickness is 6mm±0.2mm; the surface curvature radius of the fourth lens facing the object plane is 7900mm±2mm, the surface curvature radius of the fourth lens facing the image plane is ﹣26mm±2mm, the refractive index of the fourth lens is 1.73, the dispersion coefficient is 40.3, the effective aperture is 26mm±1mm, and the center thickness is 9mm±0.2mm; the surface curvature radius of the fifth lens facing the object plane is ﹣26mm±2mm, the surface curvature radius of the fifth lens facing the image plane is 25mm±2mm, the refractive index of the fifth lens is 1.65, the dispersion coefficient is 34, the effective aperture is 26mm±1mm, and the center thickness is 9mm±0.2mm.

2. The long working distance zoom lens according to claim 1, characterized in that: The total focal length of the zoom lens is f, the combined focal length of the first lens, the second lens and the third lens is f1, and the combined focal length of the fourth lens and the fifth lens is f2, then the formulas are satisfied: 0.5<|f1 / f|<0.7; 0.25<|f2 / f|<0.

4.

3. The long working distance zoom lens according to claim 1, characterized in that: The distance between the object plane and the first lens is 819 mm, the distance between the first lens and the second lens is 2 mm, the distance between the third lens and the fourth lens is 15.6 mm, and the distance between the fifth lens and the image plane is 111 mm.

4. The long working distance zoom lens according to claim 1, characterized in that: The distance between the object plane and the first lens is 550 mm, the distance between the first lens and the second lens is 3.2 mm, the distance between the third lens and the fourth lens is 18.2 mm, and the distance between the fifth lens and the image plane is 122 mm.

5. The long working distance zoom lens according to claim 1, characterized in that: The distance between the object plane and the first lens is 400 mm, the distance between the first lens and the second lens is 4.6 mm, the distance between the third lens and the fourth lens is 21.6 mm, and the distance between the fifth lens and the image plane is 138 mm.

Images