Small-sized long-working-distance industrial lens

Abstract

The utility model relates to the technical field of industrial lenses, and provides a small-sized long-working-distance industrial lens, which comprises a shell and a front optical assembly, the front optical assembly is arranged in the shell, and the front optical assembly comprises a diaphragm, a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged along the incident direction of light, the first lens is a biconvex lens, the second lens is a negative meniscus lens, the first lens and the second lens are combined into a first doublet lens, the third lens is a biconcave lens, the fourth lens is a positive meniscus lens, and the third lens and the fourth lens are combined into a second doublet lens. According to the technical scheme, the problem that an existing industrial lens cannot meet the requirements in the aspects of precision detection and measurement is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of industrial lenses, and specifically, to a small long working distance industrial lens. Background Art

[0002] In the semiconductor manufacturing process, it is necessary to conduct detailed inspections on tiny chips and circuits. The small long working distance industrial lens can capture high-definition local images without contacting the chips, which helps to accurately detect and identify defects and flaws on the chips. For precision mechanical parts, such as gears, bearings, etc., high-precision dimensional measurement and surface quality inspection are required. This kind of lens can capture the minute details of the parts at a long working distance, helping the inspectors accurately judge the quality of the parts. In short, the small long working distance industrial lens is suitable for use in narrow scenarios that require high-precision and high-definition imaging and need to maintain a certain working distance. It can meet the needs of various precision inspections and measurements, improving work efficiency and accuracy.

[0003] However, the existing industrial lenses cannot meet the requirements of precision inspections and measurements. Therefore, there is an urgent need for a new long working distance industrial lens. Summary of the Utility Model

[0004] The utility model provides a small long working distance industrial lens, which solves the problem that the existing industrial lenses cannot meet the requirements in precision inspections and measurements.

[0005] The technical solution of the utility model is as follows: A small long working distance industrial lens includes a housing and a front optical component. The front optical component is arranged inside the housing. The front optical component includes a diaphragm, a first lens, a second lens, a third lens, and a fourth lens arranged in sequence along the light incident direction. The first lens is a biconvex lens, the second lens is a negative meniscus lens, the first lens and the second lens are combined into a first doublet lens, the third lens is a biconcave lens, the fourth lens is a positive meniscus lens, and the third lens and the fourth lens are combined into a second doublet lens.

[0006] As a further technical solution, the distance between the diaphragm and the object surface is 150 mm, the distance between the front surface of the first lens and the diaphragm is 3 mm, the distance between the rear surface of the second lens and the front surface of the third lens is 58.7 mm, and the distance between the rear surface of the fourth lens and the image surface is 48 mm.

[0007] As a further technical solution, the focal length of the first doublet lens is f1, the focal length of the second doublet lens is f2, and the focal length of the small long working distance industrial lens is f. Among them, 0.3 < |f1 / f| < 0.5; 1 < |f2 / f| < 2.

[0008] As a further technical solution, the front surface curvature radius of the first lens is 55.6 ± 0.2 mm, the rear surface curvature radius is -15 ± 0.2 mm, the refractive index is 1.52, the dispersion coefficient is 64.2, the effective aperture is 10 ± 1 mm, and the central thickness of the lens is 3.4 ± 0.2 mm.

[0009] As a further technical solution, the front surface curvature radius of the second lens is -15 ± 0.2 mm, the rear surface curvature radius is -34 ± 0.2 mm, the refractive index is 1.62, the dispersion coefficient is 36.3, the effective aperture is 10 ± 1 mm, and the central thickness of the lens is 1 ± 0.2 mm.

[0010] As a further technical solution, the front surface curvature radius of the third lens is -10 ± 0.2 mm, the rear surface curvature radius is 6 ± 0.2 mm, the refractive index is 1.52, the dispersion coefficient is 64.2, the effective aperture is 8 ± 1 mm, and the central thickness of the lens is 1 ± 0.2 mm.

[0011] As a further technical solution, the front surface curvature radius of the fourth lens is 6 ± 0.2 mm, the rear surface curvature radius is 20 ± 0.2 mm, the refractive index is 1.62, the dispersion coefficient is 36.3, the effective aperture is 8 ± 1 mm, and the central thickness of the lens is 2.5 ± 0.2 mm.

[0012] The beneficial effects of the present utility model are as follows: First, the simple and unique design greatly reduces the processing cost and difficulty of the small long working distance industrial lens; second, the use of the diffraction limit design method greatly improves the clarity and uniformity of the image plane; finally, the combination of the first doublet lens and the second doublet lens provides a basis for the design structure for designing different working distances, different focal lengths, different lengths, and matching different cameras in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0014] Figure 1 It is a schematic structural diagram of the front optical assembly with the aperture hidden provided by the present utility model;

[0015] Figure 2 It is a high-resolution schematic diagram of the lens provided by the present utility model;

[0016] Figure 3 It is a low distortion effect diagram of the lens provided by the present utility model.

[0017] In the figure: 1, the first lens; 2, the second lens; 3, the third lens; 4, the fourth lens; 5, the image plane. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.

[0019] As Figure 1 shown, the present invention provides a small long working distance industrial lens, including a housing and a front optical component. The front optical component is disposed within the housing. The front optical component includes a diaphragm, a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4 arranged in sequence along the light incident direction. The first lens 1 is a biconvex lens, the second lens 2 is a negative meniscus lens, the first lens 1 and the second lens 2 are combined into a first doublet lens, the third lens 3 is a biconcave lens, the fourth lens 4 is a positive meniscus lens, and the third lens 3 and the fourth lens 4 are combined into a second doublet lens.

[0020] The distance between the diaphragm and the object surface is 150 mm, the distance between the front surface of the first lens 1 and the diaphragm is 3 mm, the distance between the rear surface of the second lens 2 and the front surface of the third lens 3 is 58.7 mm, and the distance between the rear surface of the fourth lens 4 and the image surface 5 is 48 mm.

[0021] The focal length of the first doublet lens is f1, the focal length of the second doublet lens is f2, and the focal length of the small long working distance industrial lens is f. Among them, 0.3 < |f1 / f| < 0.5; 1 < |f2 / f| < 2.

[0022] The front surface curvature radius of the first lens 1 is 55.6 ± 0.2 mm, the rear surface curvature radius is -15 ± 0.2 mm, the refractive index is 1.52, the dispersion coefficient is 64.2, the effective aperture is 10 ± 1 mm, and the central thickness of the lens is 3.4 ± 0.2 mm. The front surface curvature radius of the second lens 2 is -15 ± 0.2 mm, the rear surface curvature radius is -34 ± 0.2 mm, the refractive index is 1.62, the dispersion coefficient is 36.3, the effective aperture is 10 ± 1 mm, and the central thickness of the lens is 1 ± 0.2 mm. The front surface curvature radius of the third lens 3 is -10 ± 0.2 mm, the rear surface curvature radius is 6 ± 0.2 mm, the refractive index is 1.52, the dispersion coefficient is 64.2, the effective aperture is 8 ± 1 mm, and the central thickness of the lens is 1 ± 0.2 mm. The front surface curvature radius of the fourth lens 4 is 6 ± 0.2 mm, the rear surface curvature radius is 20 ± 0.2 mm, the refractive index is 1.62, the dispersion coefficient is 36.3, the effective aperture is 8 ± 1 mm, and the central thickness of the lens is 2.5 ± 0.2 mm.

[0023] Due to its simple and unique design structure, the small-sized industrial lens with a long working distance provided by the present utility model can operate in a narrow environment, and can also reduce its own processing cost and processing difficulty. Even in the later operation and maintenance, not much effort needs to be invested. In addition, the combined form of the first doublet lens and the second doublet lens can provide more matching solutions for cameras in different working distances, different focal lengths and different lengths in the future.

[0024] As Figures 2 to 3 shown, the present utility model also adopts the design method of diffraction limit, thereby improving the imaging effect of light on the image plane 5 after passing through the first lens 1, the second lens 2, the third lens 3 and the fourth lens 4, and improving the clarity and uniformity of the image plane 5. The design method of using the diffraction limit in optical design is to use the diffraction limit formula sinθ = 1.22λ / D. Where θ is the angular resolution, λ is the wavelength, and D is the aperture diameter. When θ is very small, sinθ is approximately equal to tagθ, approximately equal to d / f, where d is the minimum resolvable size and f is the focal length. It can be considered that d / f = 1.22λ / D, and f / D = d / 1.22λ is derived. f / D, that is, the focal length / aperture diameter, is the aperture F value we often mention. When the F value is smaller, the resolution is higher. Such an idea close to the ideal design can obtain the highest resolution. In addition, the design idea of setting the aperture at the image-side focal point of the microscope objective to make it a telecentric lens corrected for infinity can solve the alignment accuracy of the object plane and also reduce the reading accuracy of the image plane, making the illuminance of the entire image plane uniform and the clarity of the entire picture consistent.

[0025] The above are only the preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A small industrial lens with a long working distance, characterized in that: The invention comprises a housing and a front optical component, wherein the front optical component is arranged in the housing, and comprises an aperture, a first lens (1), a second lens (2), a third lens (3) and a fourth lens (4) arranged in sequence along the incident direction of light, wherein the first lens (1) is a biconvex lens, the second lens (2) is a negative meniscus lens, the first lens (1) and the second lens (2) are combined into a first double-cemented lens, the third lens (3) is a biconcave lens, the fourth lens (4) is a positive meniscus lens, and the third lens (3) and the fourth lens (4) are combined into a second double-cemented lens.

2. A small industrial lens with a long working distance according to claim 1, characterized in that: The distance between the aperture and the object plane is 150 mm, the distance between the front surface of the first lens (1) and the aperture is 3 mm, the distance between the rear surface of the second lens (2) and the front surface of the third lens (3) is 58.7 mm, and the distance between the rear surface of the fourth lens (4) and the image plane (5) is 48 mm.

3. The small industrial lens with long working distance according to claim 1, characterized in that: The focal length of the first double-cemented lens is f1, the focal length of the second double-cemented lens is f2, and the focal length of the small long working distance industrial lens is f, wherein 0.3<|f1 / f|<0.5; 1<|f2 / f|<2.

4. The small industrial lens with long working distance according to claim 1, characterized in that: The first lens (1) has a front surface curvature radius of 55.6±0.2 mm, a rear surface curvature radius of -15±0.2 mm, a refractive index of 1.52, a dispersion coefficient of 64.2, an effective aperture of 10±1 mm, and a center thickness of 3.4±0.2 mm.

5. The small industrial lens with long working distance according to claim 1, characterized in that: The second lens (2) has a front surface curvature radius of -15±0.2 mm, a rear surface curvature radius of -34±0.2 mm, a refractive index of 1.62, a dispersion coefficient of 36.3, an effective aperture of 10±1 mm, and a center thickness of 1±0.2 mm.

6. The small industrial lens with long working distance according to claim 1, characterized in that: The third lens (3) has a front surface curvature radius of -10±0.2 mm, a rear surface curvature radius of 6±0.2 mm, a refractive index of 1.52, a dispersion coefficient of 64.2, an effective aperture of 8±1 mm, and a center thickness of 1±0.2 mm.

7. The small industrial lens with long working distance according to claim 1, characterized in that: The fourth lens (4) has a front surface curvature radius of 6±0.2 mm, a rear surface curvature radius of 20±0.2 mm, a refractive index of 1.62, a dispersion coefficient of 36.3, an effective aperture of 8±1 mm, and a center thickness of 2.5±0.2 mm.

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