CN211603700U - Low-distortion lens - Google Patents
Low-distortion lens Download PDFInfo
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- CN211603700U CN211603700U CN202020203895.XU CN202020203895U CN211603700U CN 211603700 U CN211603700 U CN 211603700U CN 202020203895 U CN202020203895 U CN 202020203895U CN 211603700 U CN211603700 U CN 211603700U
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Abstract
The utility model discloses a low distortion camera lens, optical device has set gradually preceding lens group to the image space by the object space, diaphragm and back lens group, preceding lens group is including the first lens that has positive focal power and falcate structure, the second lens that has positive focal power and falcate structure, and the third lens that has negative focal power and falcate structure, back lens group is including the fourth lens that has negative focal power and biconcave structure, the fifth lens that has positive focal power and biconvex structure, the sixth lens that has positive focal power and falcate structure, and the seventh lens that has positive focal power and biconvex structure, optical device's focus is f, the focus of preceding lens group is fS1Focal length of rear lens group is fS2Respectively satisfy the condition of offIs represented by the following formula: 1.5<|fS1/f|<2.5；0.4<|fS2/f|<0.8. The utility model discloses can match the camera of 2.2 mu m pixel chip.
Description
Technical Field
The utility model belongs to the technical field of optical imaging, concretely relates to low distortion camera lens.
Background
In the large background of industrial 4.0, machine vision is becoming popular for industrial applications as a key technology. The demand of industrial lenses as the core of machine vision is also continuously expanding, especially the application in precision measurement and detection is more prominent, and the adoption of a machine vision system to replace human detection and judgment is an irreversible development trend. The machine vision detection systems need to be matched with industrial lenses with high resolution and low distortion so as to improve the detection precision of the system. However, the domestic existing industrial lenses generally have the defects of different types or different degrees, such as low pixels, narrow working distance, large distortion and the like, so the research and development of the industrial lenses with high pixels and low distortion are more urgent.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a: aiming at the defects of the prior art, the camera lens with low distortion and good chromatic aberration correction capability is provided, the requirement of high resolution is met, and the camera lens can be matched with a 2.2 mu m pixel chip.
In order to achieve the above purpose, the utility model adopts the following technical scheme:
a low-distortion lens comprises an optical device, wherein the optical device is sequentially provided with a front lens group S1, a diaphragm and a rear lens group S2 from an object side to an image side, the front lens group S1 comprises a first lens G1 with a positive focal power and a meniscus structure, a second lens G2 with a positive focal power and a meniscus structure and a third lens G3 with a negative focal power and a meniscus structure, the rear lens group S2 comprises a fourth lens G4 with a negative focal power and a biconcave structure, a fifth lens G5 with a positive focal power and a biconvex structure, a sixth lens G6 with a positive focal power and a meniscus structure and a seventh lens G7 with a positive focal power and a biconvex structure, the focal length of the optical device is f, and the focal length of the front lens group S1 is fS1The focal length of the rear lens group S2 is fS2Respectively satisfy the relational expressions: 1.5<|fS1/f|<2.5；0.4<|fS2/f|<0.8。
As an improvement of the low distortion lens of the present invention, the first lens G1, the second lens G2, the third lens G3, the fourth lens G4, the fifth lens G5, the sixth lens G6 and the seventh lens G7 are all spherical mirrors.
As an improvement of a low distortion lens, optical back intercept BFL of optical device with optical device's focus f satisfies the relational expression: i BFL/f I is less than 0.8.
As an improvement of the low distortion lens, the half-image height y' of the optical device and the focal length f of the optical device satisfy the relation: the | y'/f | is less than 0.3.
As an improvement of the low distortion lens of the present invention, the refractive index of the first lens G1 is n1, and satisfies the following relation: 1.65 < n1 < 1.80.
As an improvement of the low distortion lens of the present invention, the second lens G2 and the third lens G3 form a first cemented lens U1, the focal length f of the first cemented lens U1U1And a focal length f of the front lens group S1S1Satisfies the relation: 2.5 < | fU1/fS1|＜4.0。
As an improvement of the low distortion lens of the present invention, the fourth lens G4 and the fifth lens G5 form a second cemented lens U2, the focal length f of the second cemented lens U2U2And a focal length f of the rear lens group S2S2Satisfies the relation: 4.0 < | fU2/fS2|＜5.0。
As an improvement of the low distortion lens of the present invention, the refractive index of the sixth lens G6 is n6, the refractive index of the seventh lens G7 is n7, and the following relation is satisfied: n6 is more than 1.65 and less than 1.80; 1.65 < n7 < 1.80.
The beneficial effects of the utility model reside in that, the utility model discloses an optical device, optical device has set gradually front lens group S1, diaphragm and back lens to the image space by the object spaceA group S2, the front lens group S1 including a first lens G1 having a positive power and a meniscus structure, a second lens G2 having a positive power and a meniscus structure, and a third lens G3 having a negative power and a meniscus structure, the rear lens group S2 including a fourth lens G4 having a negative power and a biconcave structure, a fifth lens G5 having a positive power and a biconvex structure, a sixth lens G6 having a positive power and a meniscus structure, and a seventh lens G7 having a positive power and a biconvex structure, the focal length of the optical device being f, the focal length of the front lens group S1 being fS1The focal length of the rear lens group S2 is fS2Respectively satisfy the relational expressions: 1.5<|fS1/f|<2.5；0.4<|fS2/f|<0.8. The utility model discloses a focus is the optical device of the high pixel of 25mm, low distortion industry camera lens, and the biggest image plane is phi 9mm, and its resolution ratio can reach 230lp/mm, and full field of vision optical distortion is less than 0.02%, and simple structure is compact, adopts the focusing mode that whole group removed, and its clear aperture also can be adjusted in a flexible way simultaneously.
Drawings
Fig. 1 is a schematic structural diagram of an optical device according to the present invention.
Fig. 2 is a light path diagram of the optical device of the present invention.
Fig. 3 is a graph of the optical distortion curve of the optical device of the present invention.
Detailed Description
As used in the specification and in the claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect.
In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", horizontal "and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, detachable connections, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.
The present invention will be described in further detail with reference to the accompanying drawings, which are not intended to limit the present invention.
As shown in fig. 1 to 3, a low distortion lens includes an optical device, the optical device includes a front lens group S1, a stop and a rear lens group S2, the front lens group S1 includes a first lens G1 having a positive focal power and a meniscus structure, a second lens G2 having a positive focal power and a meniscus structure, and a third lens G3 having a negative focal power and a meniscus structure, the rear lens group S2 includes a fourth lens G4 having a negative focal power and a biconcave structure, a fifth lens G5 having a positive focal power and a biconvex structure, a sixth lens G6 having a positive focal power and a meniscus structure, and a seventh lens G7 having a positive focal power and a biconvex structure, a focal length of the optical device is f, and a focal length of the front lens group S1 is fS1The focal length of the rear lens group S2 is fS2Respectively satisfy the relational expressions: 1.5<|fS1/f|<2.5；0.4<|fS2/f|<0.8。
Preferably, the first lens G1, the second lens G2, the third lens G3, the fourth lens G4, the fifth lens G5, the sixth lens G6, and the seventh lens G7 are all spherical mirrors.
Preferably, the optical back intercept BFL of the optical device and the focal length f of the optical device satisfy the relation: i BFL/f I is less than 0.8.
Preferably, the half-image height y' of the optical device and the focal length f of the optical device satisfy the relation: the | y'/f | is less than 0.3.
Preferably, the refractive index of the first lens G1 is n1, and satisfies the relation: 1.65 < n1 < 1.80.
Preferably, the second lens G2 and the third lens G3 form a first cemented lens U1, and the focal length f of the first cemented lens U1U1And focal length f of front lens group S1S1Satisfies the relation: 2.5 < | fU1/fS1|＜4.0。
Preferably, the fourth lens G4 and the fifth lens G5 form a second cemented lens U2, and the focal length f of the second cemented lens U2U2And focal length f of rear lens group S2S2Satisfies the relation: 4.0 < | fU2/fS2|＜5.0。
Preferably, the refractive index of the sixth lens G6 is n6, and the refractive index of the seventh lens G7 is n7, while satisfying the relationship: n6 is more than 1.65 and less than 1.80; 1.65 < n7 < 1.80.
Specific optical device data are as follows:
| surface of | Radius of | Thickness of | Refraction |
| Front surface of G1 | 29.9 | 4.0 | 1.7 |
| Rear surface of G1 | 124.4 | 2.9 | |
| U1 front surface | 12.5 | 2.2 | 1.8 |
| U1 cemented surface | 121.9 | 3.8 | 1.6 |
| U1 rear surface | 7.7 | 2.1 | |
| Diaphragm | Plane surface | 5.1 | |
| U2 front surface | -6.7 | 2.4 | 1.6 |
| U2 cemented surface | 109.8 | 2.3 | 1.7 |
| U2 rear surface | -11.0 | 0.1 | |
| Front surface of G6 | -81.1 | 2.0 | 1.7 |
| Rear surface of G6 | -22.8 | 0.1 | |
| Front surface of G7 | 45.8 | 1.8 | 1.7 |
| Rear surface of G7 | -45.8 | 14.7 | |
| Image plane | Plane surface |
In the embodiment, the focal length F of the optical device is 25mm, the maximum aperture is F # -2.8, and the front lens passes throughFocal length f of lens group S1S149.54mm, focal length f of the rear group lens group S2S216.49mm, focal length f of the first cemented lens U1U1Focal length f of the second cemented lens U2 ═ 159.71mmU2-72.66mm, optical back intercept BFL 14.7mm, and half image height y' 4.5 mm.
Each relation:
|fS1/f|＝1.98；|fS2/f|＝0.66；|BFL/f|＝0.59；
|y’/f|＝0.18；|fU1/fS1|＝3.22；|fU2/fS2|＝4.41。
satisfy the relation:
1.5<|fS1/f|<2.5；0.4<|fS2/f|<0.8；|BFL/f|＜0.8；
|y’/f|＜0.3；2.5＜|fU1/fS1|＜4.0；4.0＜|fU2/fS2|＜5.0。
the optical device of the industrial lens with high pixels and low distortion and the focal length of 25mm is realized through the structure, the maximum imaging surface is phi 9mm, the resolution ratio can reach 230lp/mm, the optical distortion of the full field of view is lower than 0.02 percent, the structure is simple and compact, the whole group moving focusing mode is adopted, and meanwhile, the clear aperture can be flexibly adjusted.
Fig. 3 shows a graph of optical distortion with a maximum optical distortion of less than 0.02% over the full field of view.
Variations and modifications to the above-described embodiments may become apparent to those skilled in the art from the disclosure and teachings of the above description. Therefore, the present invention is not limited to the above-mentioned embodiments, and any obvious modifications, replacements or variations made by those skilled in the art on the basis of the present invention belong to the protection scope of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Claims (8)
1. A low distortion lens, characterized in that: comprising an optical device, said optical deviceThe device is provided with a front lens group S1, a diaphragm and a rear lens group S2 in sequence from an object side to an image side, wherein the front lens group S1 comprises a first lens G1 with positive focal power and a meniscus structure, a second lens G2 with positive focal power and a meniscus structure and a third lens G3 with negative focal power and a meniscus structure, the rear lens group S2 comprises a fourth lens G4 with negative focal power and a double-concave structure, a fifth lens G5 with positive focal power and a double-convex structure, a sixth lens G6 with positive focal power and a meniscus structure and a seventh lens G7 with positive focal power and a double-convex structure, the focal length of the optical device is f, and the focal length of the front lens group S1 is fS1The focal length of the rear lens group S2 is fS2Respectively satisfy the relational expressions: 1.5<|fS1/f|<2.5；0.4<|fS2/f|<0.8。
2. A low distortion lens as defined in claim 1, wherein: the first lens G1, the second lens G2, the third lens G3, the fourth lens G4, the fifth lens G5, the sixth lens G6, and the seventh lens G7 are all spherical mirrors.
3. A low distortion lens as defined in claim 1, wherein: the optical back intercept BFL of the optical device and the focal length f of the optical device satisfy the relation: i BFL/f I is less than 0.8.
4. A low distortion lens as defined in claim 1, wherein: the half-image height y' of the optical device and the focal length f of the optical device satisfy the relation: the | y'/f | is less than 0.3.
5. A low distortion lens as defined in claim 1, wherein: the refractive index of the first lens G1 is n1, and the relation is satisfied: 1.65 < n1 < 1.80.
6. A low distortion lens as defined in claim 1, wherein: the second lens G2 and the third lens G3 constitute a first cemented lensU1, focal length f of the first cemented lens U1U1And a focal length f of the front lens group S1S1Satisfies the relation: 2.5 < | fU1/fS1|＜4.0。
7. A low distortion lens as defined in claim 1, wherein: the fourth lens G4 and the fifth lens G5 constitute a second cemented lens U2, the focal length f of the second cemented lens U2U2And a focal length f of the rear lens group S2S2Satisfies the relation: 4.0 < | fU2/fS2|＜5.0。
8. A low distortion lens as defined in claim 1, wherein: the refractive index of the sixth lens G6 is n6, and the refractive index of the seventh lens G7 is n7, and the relation: n6 is more than 1.65 and less than 1.80; 1.65 < n7 < 1.80.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020203895.XU CN211603700U (en) | 2020-02-25 | 2020-02-25 | Low-distortion lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020203895.XU CN211603700U (en) | 2020-02-25 | 2020-02-25 | Low-distortion lens |
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| Publication Number | Publication Date |
|---|---|
| CN211603700U true CN211603700U (en) | 2020-09-29 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202020203895.XU Active CN211603700U (en) | 2020-02-25 | 2020-02-25 | Low-distortion lens |
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| CN (1) | CN211603700U (en) |
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