Industrial lens structure

Abstract

The invention discloses an industrial lens structure and a manufacturing method thereof. Comprising a first lens L1 with negative focal power, a second lens L2 with negative focal power, a third lens L3 with negative focal power, a fourth lens L4 with negative focal power, a fifth lens L5 with positive focal power, a sixth lens L6 with positive focal power, a seventh lens L7 with positive focal power, an eighth lens L8 with negative focal power and a ninth lens L9 with positive focal power in sequence from an object side to an image side, and a diaphragm STOP is arranged among the tenth lens L10 with positive focal power, the eleventh lens L11 with negative focal power, the twelfth lens L12 with positive focal power, the seventh lens L7 and the eighth lens L8. Under the conditions of a large target surface, a large visual field and a large aperture, full-visual-field high resolution can be achieved, the number of used lenses is small, and good economic cost is achieved.

Description

Technical Field

[0001] This invention relates to the field of industrial lens imaging optics technology, and more particularly to an industrial lens structure. Background Technology

[0002] With the continuous upgrading of China's manufacturing industry and the rapid development of industrial automation, the requirements for machine vision equipment are becoming increasingly stringent. Large-size target surface image sensors are being further applied, while the individual pixel units of these sensors are becoming smaller and smaller. Consequently, the requirements for corresponding industrial lenses are also constantly increasing. Currently, most industrial lenses on the market have small image planes, which do not match the large-size image sensors well. Moreover, they cannot achieve high resolution across the entire field of view at continuous long working distances. Some lenses that can achieve high resolution across the entire field of view at continuous long working distances have relatively low relative illumination, resulting in poor brightness uniformity in the image.

[0003] Therefore, existing technologies have shortcomings and need to be improved. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide an industrial lens structure that solves the problem that existing lenses cannot simultaneously achieve the requirements of a large field of view and high relative illumination, while maintaining high resolution across the entire field of view over a continuous long working distance.

[0005] The technical solution of the present invention is as follows: An industrial lens structure is provided, comprising, from the object side to the image side, the following lenses in sequence: a first lens L1 with negative optical power, a second lens L2 with negative optical power, a third lens L3 with negative optical power, a fourth lens L4 with negative optical power, a fifth lens L5 with positive optical power, a sixth lens L6 with positive optical power, a seventh lens L7 with positive optical power, an eighth lens L8 with negative optical power, a ninth lens L9 with positive optical power, a tenth lens L10 with positive optical power, an eleventh lens L11 with negative optical power, and a twelfth lens L12 with positive optical power; an aperture stop (STOP) is located between the seventh lens L7 and the eighth lens L8; lenses L1 to L7 form a front group G1, and lenses L8 to L12 form a rear group G2. When the lens is focused between a working distance of 0.1m and infinity, the rear group G2 moves between the aperture stop (STOP) and the imaging plane, while the distances between the aperture stop (STOP) and the front group G1 relative to the imaging plane remain unchanged.

[0006] The eighth lens L8 and the ninth lens L9 form the first cemented lens group, and the tenth lens L10 and the eleventh lens L11 form the second cemented lens group. Both L9 and L10 use a non-linear relative partial dispersion P. x,y The glass material is designed to correct chromatic aberration across the entire lens to the greatest extent possible.

[0007] Lenses L1 to L4 form lens combination S1, lenses L5 to L7 form lens combination S2, and lenses L8 to L12 form lens combination S3. All lenses in combination S1 are concave lenses, mainly used to achieve lens miniaturization and field curvature correction. All lenses in combination S2 are positive power lenses, mainly used to achieve lens distortion correction. The structure of combination S3 is mainly used to achieve lens astigmatism and chromatic aberration correction.

[0008] The first, second, and third lenses are all meniscus lenses, and their object-facing surfaces are all convex. The eighth lens L8 is a meniscus lens, and its object-facing surface is convex. The fourth lens L4 is a biconcave lens. The fifth lens L5, sixth lens L6, seventh lens L7, ninth lens L9, tenth lens L10, and twelfth lens L12 are all biconvex lenses. The eleventh lens L11 is a meniscus lens, and its object-facing surface is concave.

[0009] The focal lengths of lens assemblies S1, S2, and S3, and the focal length of the lens, respectively satisfy the following conditions: 0.5 < |f S1 / f|<1.0, 1.5 < |f S2 / f|<2.0, 3.0 < |f S3 / f|<3.5, In the above conditions, f is the effective focal length of the entire lens. S1 f S2 f S3 The effective focal lengths of the lens combinations S1, S2, and S3 are respectively, and the unit is mm.

[0010] The focal lengths of the front group G1 and the rear group G2, and the focal length of the lens, respectively satisfy the following conditions: 1.3 < |f G1 / f|<1.8, 3.0 < |f G2 / f|<3.5, In the above conditions, f is the effective focal length of the entire lens. G1 and f G2 These correspond to the effective focal lengths of the front group G1 and the rear group G2, respectively, and are both in mm.

[0011] The fifth lens L5, the sixth lens L6, and the seventh lens L7 are all positive power monolithic lenses, and both the object-side and image-side surfaces are convex, and they satisfy the following conditions: 0.65 < T L7 / D L7 <0.85, TL7 It is the center thickness of the seventh lens, L7, D. L7 It is the maximum effective optical diameter of the seventh lens L7, and the units are all in mm; this structure is beneficial for the correction of large field-of-view distortion.

[0012] The parameters of each component in a preferred embodiment of the industrial lens structure are as follows:

[0013] It has the following properties: Focal length: f = 8.12 ± 0.1 mm Maximum imaging area: ∮19.3mm Maximum aperture (FN.O): 2.8 Working distance: ≥0.1m Maximum angle of view: greater than 106°.

[0014] Under working distances of 0.3m to 1.5m and FN.O3.8 conditions, the performance of the aforementioned industrial lens structure meets the following standards: Center field of view: 250 lp / mm, contrast ratio greater than 28.5%; Edge field of view: 180 lp / mm contrast ratio greater than 20.0%; Relative illumination: greater than 75%.

[0015] By adopting the above solution, the present invention provides an industrial lens structure, which has the following technical effects: 1. This invention can achieve high resolution across the entire field of view under conditions of large target surface, large field of view, and large aperture.

[0016] 2. This invention can maintain a performance of 1 even at a relatively long working distance.

[0017] 3. It uses fewer lenses, resulting in good economic costs. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the industrial lens of the present invention; Figure 2 This is a graph of the optical transfer function (MTF) of the present invention at an operating distance of 0.3m under FN.O3.8 conditions; Figure 3 This is a graph of the optical transfer function (MTF) of the present invention at a working distance of 1.5m under FN.O3.8 conditions; Figure 4 This is the relative illuminance diagram of the present invention at a working distance of 1.5m under FN.O3.8. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0020] Please see Figures 1-4 This invention provides an industrial lens structure, comprising, from the object side to the image side, the following lenses in sequence: a first lens L1 with negative optical power, a second lens L2 with negative optical power, a third lens L3 with negative optical power, a fourth lens L4 with negative optical power, a fifth lens L5 with positive optical power, a sixth lens L6 with positive optical power, a seventh lens L7 with positive optical power, an eighth lens L8 with negative optical power, a ninth lens L9 with positive optical power, a tenth lens L10 with positive optical power, an eleventh lens L11 with negative optical power, and a twelfth lens L12 with positive optical power. An aperture stop (STOP) is located between the seventh lens L7 and the eighth lens L8. Lenses L1 to L7 form a front group G1, and lenses L8 to L12 form a rear group G2. When the lens is focused between a working distance of 0.1m and infinity, the rear group G2 moves between the aperture stop (STOP) and the imaging plane, while the distances between the aperture stop (STOP) and the front group G1 relative to the imaging plane remain unchanged.

[0021] The eighth lens L8 and the ninth lens L9 are combined to form the first cemented lens group, and the tenth lens L10 and the eleventh lens L11 are combined to form the second cemented lens group.

[0022] Lenses L1 to L4 form lens combination S1, lenses L5 to L7 form lens combination S2, and lenses L8 to L12 form lens combination S3. All lenses in combination S1 are concave lenses, mainly used to achieve lens miniaturization and field curvature correction. All lenses in combination S2 are positive power lenses, mainly used to achieve lens distortion correction. The structure of combination S3 is mainly used to achieve lens astigmatism and chromatic aberration correction.

[0023] The first, second, and third lenses are all meniscus lenses, and their object-facing surfaces are all convex. The eighth lens L8 is a meniscus lens, and its object-facing surface is convex. The fourth lens L4 is a biconcave lens. The fifth lens L5, sixth lens L6, seventh lens L7, ninth lens L9, tenth lens L10, and twelfth lens L12 are all biconvex lenses. The eleventh lens L11 is a meniscus lens, and its object-facing surface is concave.

[0024] The focal lengths of lens assemblies S1, S2, and S3, and the focal length of the lens, respectively satisfy the following conditions: 0.5 < |f S1 / f|<1.0, 1.5 < |f S2 / f|<2.0, 3.0 < |f S3 / f|<3.5, In the above conditions, f is the effective focal length of the entire lens. S1 f S2 f S3 The effective focal lengths of the lens combinations S1, S2, and S3 are respectively, and the unit is mm.

[0025] The focal lengths of the front group G1 and the rear group G2, and the focal length of the lens, respectively satisfy the following conditions: 1.3 < |f G1 / f|<1.8, 3.0 < |f G2 / f|<3.5, In the above conditions, f is the effective focal length of the entire lens. G1 and f G2 These correspond to the effective focal lengths of the front group G1 and the rear group G2, respectively, and are both in mm.

[0026] The fifth lens L5, the sixth lens L6, and the seventh lens L7 are all positive power monolithic lenses, and both the image-side and object-side surfaces are convex, and they satisfy the following conditions: 0.65 < T L7 / D L7 <0.85, T L7 It is the center thickness of the seventh lens, L7, D. L7 It is the maximum effective optical diameter of the seventh lens L7, and the units are all in mm; this structure is beneficial for the correction of large field-of-view distortion.

[0027] The parameters of each component in a preferred embodiment of the industrial lens structure are as follows:

[0028] Please see Figures 2-4 It has the following properties: Focal length: f = 8.12 ± 0.1 mm Maximum imaging area: ∮19.3mm Maximum aperture (FN.O): 2.8 Working distance: ≥0.1m Maximum angle of view: greater than 106°.

[0029] Under working distances of 0.3m to 1.5m and FN.O3.8 conditions, the performance of the aforementioned industrial lens structure meets the following standards: Center field of view: 250 lp / mm, contrast ratio greater than 28.5%; Edge field of view: 180 lp / mm contrast ratio greater than 20.0%; Relative illumination: greater than 75%.

[0030] In summary, the present invention provides an industrial lens structure with the following technical advantages: 1. This invention can achieve high resolution across the entire field of view under conditions of large target surface, large field of view, and large aperture.

[0031] 2. This invention can maintain a performance of 1 even at a relatively long working distance.

[0032] 3. It uses fewer lenses, resulting in good economic costs.

[0033] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An industrial lens structure, characterized in that, include: From the object side to the image side, the lens consists of: a first lens L1 with negative optical power, a second lens L2 with negative optical power, a third lens L3 with negative optical power, a fourth lens L4 with negative optical power, a fifth lens L5 with positive optical power, a sixth lens L6 with positive optical power, a seventh lens L7 with positive optical power, an eighth lens L8 with negative optical power, a ninth lens L9 with positive optical power, a tenth lens L10 with positive optical power, an eleventh lens L11 with negative optical power, and a twelfth lens L12 with positive optical power. The aperture stop is located between the seventh lens L7 and the eighth lens L8. Lenses L1 to L7 form the front group G1, and lenses L8 to L12 form the rear group G2. When the lens is focused between a working distance of 0.1m and infinity, the rear group G2 moves between the aperture stop and the image plane, while the distances between the aperture stop and the front group G1 relative to the image plane remain unchanged.

2. The industrial lens structure according to claim 1, characterized in that, The eighth lens L8 and the ninth lens L9 are combined to form the first cemented lens group, and the tenth lens L10 and the eleventh lens L11 are combined to form the second cemented lens group.

3. The industrial lens structure according to claim 1, characterized in that, Lenses L1 to L4 form lens combination S1, lenses L5 to L7 form lens combination S2, and lenses L8 to L12 form lens combination S3. All lenses in combination S1 are concave lenses, used to achieve lens miniaturization and field curvature correction. All lenses in combination S2 are positive power lenses, used to achieve lens distortion correction. The structure of combination S3 is used to achieve lens astigmatism and chromatic aberration correction.

4. The industrial lens structure according to claim 1, characterized in that, The first, second, and third lenses are all meniscus lenses, and their object-facing surfaces are all convex. The eighth lens L8 is a meniscus lens, and its object-facing surface is convex. The fourth lens L4 is a biconcave lens. The fifth lens L5, sixth lens L6, seventh lens L7, ninth lens L9, tenth lens L10, and twelfth lens L12 are all biconvex lenses. The eleventh lens L11 is a meniscus lens, and its object-facing surface is concave.

5. The industrial lens structure according to claim 1, characterized in that, The focal lengths of lens assemblies S1, S2, and S3, and the focal length of the lens, respectively satisfy the following conditions: 0.5<|f S1 / f|<1.0, 1.5<|f S2 / f|<2.0, 3.0<|f S3 / f|<3.5, In the above conditions, f is the effective focal length of the entire lens. S1 f S2 f S3 The effective focal lengths of the lens combinations S1, S2, and S3 are respectively, and the unit is mm.

6. The industrial lens structure according to claim 1, characterized in that, The focal lengths of the front group G1 and the rear group G2, and the focal length of the lens, respectively satisfy the following conditions: 1.3<|f G1 / f|<1.8, 3.0<|f G2 / f|<3.5, In the above conditions, f is the effective focal length of the entire lens. G1 and f G2 These correspond to the effective focal lengths of the front group G1 and the rear group G2, respectively, and are both in mm.

7. The industrial lens structure according to claim 1, characterized in that, The fifth lens L5, the sixth lens L6, and the seventh lens L7 are all positive power monolithic lenses, and both the object-side and image-side surfaces are convex, and they satisfy the following conditions: 0.65<T L7 / D L7 <0.85, T L7 It is the center thickness of the seventh lens, L7, D. L7 It is the maximum effective optical diameter of the seventh lens L7, and the units are all in mm; this structure is beneficial for the correction of large field-of-view distortion.

8. The industrial lens structure according to claim 1, characterized in that, The parameters of each component in the aforementioned industrial lens structure are as follows: It has the following properties: Focal length: f = 8.12 ± 0.1 mm Maximum imaging area: ∮19.3mm Maximum aperture (FN.O): 2.8 Working distance: ≥0.1m Maximum angle of view: greater than 106°.

9. The industrial lens structure according to claim 8, characterized in that, Under working distances of 0.3m to 1.5m and FN.O3.8 conditions, the performance of the aforementioned industrial lens structure meets the following standards: Center field of view: 250 lp / mm, contrast ratio greater than 28.5%; Edge field of view: 180 lp / mm contrast ratio greater than 20.0%; Relative illumination: greater than 75%.

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