CN111208631B - Telecentric optical path with double multiplying power - Google Patents
Telecentric optical path with double multiplying power Download PDFInfo
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- CN111208631B CN111208631B CN202010018579.XA CN202010018579A CN111208631B CN 111208631 B CN111208631 B CN 111208631B CN 202010018579 A CN202010018579 A CN 202010018579A CN 111208631 B CN111208631 B CN 111208631B
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/22—Telecentric objectives or lens systems
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
- G02B13/0055—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element
- G02B13/0065—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element having a beam-folding prism or mirror
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Abstract
The invention relates to the technical field of lenses, in particular to a double-magnification telecentric optical path, which comprises a front-end lens group, a first rear-end lens group and a second rear-end lens group; the front end lens group comprises a first lens group and a beam splitter prism, wherein the first lens group and the beam splitter prism are sequentially arranged from an object space to a first image space and have positive focal lengths; the first rear lens group comprises a first diaphragm, a second lens group with a negative focal length, a third lens group with a negative focal length and a fourth lens group with a positive focal length which are sequentially arranged from the beam splitter prism to the first image space; the second rear end lens group comprises a second diaphragm, a fifth lens group with positive focal length, a reflector and a sixth lens group with positive focal length, a part of light beams sequentially pass through the second diaphragm, the fifth lens group, the reflector and the sixth lens group after the light beams are split by the splitting prism, and the optical axis of the sixth lens group is parallel to the optical axis of the first rear end lens group. The double-magnification telecentric optical path provided by the invention can realize the effects of large visual field, high detection efficiency and small volume.
Description
Technical Field
The invention relates to the technical field of lenses, in particular to a double-magnification telecentric optical path.
Background
The telecentric lens is a high-end machine vision lens, and is characterized by that it can eliminate the problem of different magnification due to the inconsistent distance between the tested object (or CCD chip) and lens, and because the telecentric lens has unique technical advantages, at present, it is specially applicable to the field of precision measurement for the requirements of high-precision detection of mechanical component measurement, plastic component measurement, glass product and medicine component measurement and electronic component measurement.
At present, the market increases to telecentric lens's demand, simultaneously requires to tighten the imaging requirement of camera lens, requires the field of vision big, and detection efficiency is high, requires high magnification simultaneously in order to promote high accuracy measurement demand. In addition, when the sensor determines that the field of view of the lens is large, the magnification of the lens is small, and it is difficult to satisfy both the large field of view and the high magnification.
At present, the structure of the double lens is adopted in the market, different multiplying powers are set, so that the detection efficiency is improved, the structure of the double lens is shown in figure 1, the two lenses belong to a vertical relation, the detection efficiency is improved through the structure, but due to the fact that the directions of the two lenses are different, the structure such as an external CCD camera can cause the problems of large volume and inconvenient installation.
Disclosure of Invention
The invention provides a double-magnification telecentric light path aiming at the problems in the prior art, which adopts a double-lens structure and has two kinds of measuring magnifications, wherein a high magnification is arranged, a reflector is added to enable the tail ends of two light paths to be parallel, the volume of a lens is effectively reduced, and the requirements of large visual field and high magnification can be simultaneously met by adopting a large-caliber front lens group.
In order to solve the technical problems, the invention adopts the following technical scheme: a double-magnification telecentric optical path comprises a front-end lens group, a first rear-end lens group and a second rear-end lens group; the front-end lens group comprises a first lens group and a light splitting prism, wherein the first lens group and the light splitting prism are sequentially arranged from an object space to a first image space and have positive focal lengths; the first rear lens group comprises a first diaphragm, a second lens group with a negative focal length, a third lens group with a negative focal length and a fourth lens group with a positive focal length which are sequentially arranged from the beam splitter prism to the first image space; the second rear end lens group comprises a second diaphragm, a fifth lens group with positive focal length, a reflector and a sixth lens group with positive focal length, a part of light beams sequentially pass through the second diaphragm, the fifth lens group, the reflector and the sixth lens group after the light beams are split by the splitting prism, and the optical axis of the sixth lens group is parallel to the optical axis of the first rear end lens group.
Preferably, the first lens group includes a first lens and a second lens which are sequentially arranged from an object space to a first image space, the first lens is a plano-convex lens, and the second lens is a convex lens of a concave-convex type.
Preferably, the second lens group includes a third lens and a fourth lens which are sequentially arranged from the object space to the first image space, the third lens is a concave-convex lens, the fourth lens is a concave-convex lens, and the third lens and the fourth lens are cemented; the third lens group comprises a fifth lens and a sixth lens which are sequentially arranged from an object space to a first image space, the fifth lens is a concave-convex lens, the sixth lens is a convex-concave lens, and the fifth lens is glued with the sixth lens; the fourth lens group comprises a seventh lens, an eighth lens and a first plane mirror which are sequentially arranged from an object space to a first image space, the seventh lens is a biconvex lens, and the eighth lens is a biconvex lens.
Preferably, the fifth lens group includes a ninth lens and a tenth lens which are sequentially arranged from the object space to the second image space, the ninth lens is a biconvex lens, the tenth lens is a plano-concave lens, and the ninth lens is cemented with the tenth lens; the sixth lens group comprises an eleventh lens, a twelfth lens, a second plane mirror and a third plane mirror which are sequentially arranged from an object space to a second image space, wherein the eleventh lens is a biconvex lens, the twelfth lens is a biconcave lens, and the eleventh lens is glued with the twelfth lens.
Preferably, the focal length of the front lens group is f, the focal length of the first rear lens group is f1, and the focal length of the second rear lens group is f2, the focal lengths f, f1, and f2 satisfy 180mm < f <280mm, | (f1/f-0.16)/0.16| ≦ 10%, and | (f2/f-0.64)/0.64| ≦ 10%.
Preferably, if the focal length of the fifth lens group is f3, the focal length f3 satisfies the following condition: f2< f 3.
Preferably, | (fbl-f)/f |, where the rear intercept of the front-end lens group is fbl, is not more than 10%.
Preferably, the focal length of the first lens is set to f5, and the focal length of the second lens is set to f6, then the focal length f5 and the focal length f6 should satisfy: the | f5/f6-1| is less than or equal to 10 percent.
Preferably, the front end lens group, the first rear end lens group and the second rear end lens group are all made of optical glass with refractive index nd larger than 1.6.
The invention has the beneficial effects that:
1. the front lens group adopts a large-caliber lens group, so that the visual field of the lens is increased;
2. the first rear-end lens group and the second rear-end lens group with different focal lengths are arranged, so that two light paths with different multiplying powers are formed, wherein the multiplying power of one light path is matched with the requirement of a large visual field, and the high multiplying power of the other light path is realized through the arrangement of the lens module, so that the detection of different multiplying powers can be simultaneously carried out, the detection efficiency is effectively improved, and the requirements of the large visual field and the high multiplying power are met;
3. the reflecting mirror is added after the light splitting of the light splitting prism, the length of the lens on one side of the light beam reflected by the light splitting prism is shortened, and two light paths are parallel, so that the length of the lens is reduced, the space volume is saved, the size of the lens is effectively reduced, and when structures such as a CCD camera and the like are assembled, the assembly structure is simpler and more convenient because the lens is on the same side. The effects of large visual field, high detection efficiency and small size are realized in the same lens.
Drawings
Fig. 1 is a schematic structural diagram of a dual lens in the prior art.
Fig. 2 is a schematic structural diagram of the present invention.
The reference numerals in fig. 1 to 2 include:
1-front lens group, 11-first lens group, 111-first lens, 112-second lens, 12-beam splitter, 2-first rear lens group, 21-first diaphragm, 22-second lens group, 221-third lens, 222-fourth lens, 23-third lens group, 231-fifth lens, 232-sixth lens, 24-fourth lens group, 241-seventh lens, 242-eighth lens, 243-first plane mirror, 3-second rear lens group, 31-second diaphragm, 32-fifth lens group, 321-ninth lens, 322-tenth lens, 33-reflector, 34-sixth lens group, 341-eleventh lens, 342-twelfth lens, 343-second plane mirror, 344-third Flat mirror.
Detailed Description
In order to facilitate understanding of those skilled in the art, the present invention will be further described with reference to the following examples and drawings, which are not intended to limit the present invention. The present invention is described in detail below with reference to the attached drawings.
A double-magnification telecentric optical path provided in this embodiment, as shown in fig. 2, includes a front-end lens group 1, a first rear-end lens group 2, and a second rear-end lens group 3; the front end lens group 1 comprises a first lens group 11 and a beam splitter prism 12 which are sequentially arranged from an object space to a first image space and have positive focal length; the first rear lens group 2 comprises a first diaphragm 21, a second lens group 22 with a negative focal length, a third lens group 23 with a negative focal length and a fourth lens group 24 with a positive focal length which are sequentially arranged from the beam splitter prism 12 to the first image space; the second rear end lens group 3 includes a second diaphragm 31, a fifth lens group 32 with positive focal length, a reflector 33 and a sixth lens group 34 with positive focal length, and after the light beam is split by the splitting prism 12, a part of the light beam sequentially passes through the second diaphragm 31, the fifth lens group 32, the reflector 33 and the sixth lens group 34, and the optical axis of the sixth lens group 34 is parallel to the optical axis of the first rear end lens group 2.
The specific structure of the first rear lens group 2 is as follows: the second lens group 22 includes a third lens 221 and a fourth lens 222 which are sequentially arranged from an object space to a first image space, the third lens 221 is a convex lens with a concave-convex shape, the fourth lens 222 is a concave lens with a concave-convex shape, and the third lens 221 and the fourth lens 222 are glued; the third lens group 23 includes a fifth lens 231 and a sixth lens 232 arranged in sequence from an object space to a first image space, the fifth lens 231 is a concave-convex lens, the sixth lens 232 is a convex-concave lens, and the fifth lens 231 and the sixth lens 232 are cemented together; the double-cemented lens can effectively eliminate chromatic aberration and amplify single chromatic aberration. The fourth lens group 24 includes a seventh lens element 241, an eighth lens element 242 and a first plane mirror 243, which are sequentially arranged from the object side to the first image side, wherein the seventh lens element 241 is a biconvex lens element, and the eighth lens element 242 is a biconvex lens element.
The specific structure of the second rear lens group 3 is as follows: the fifth lens group 32 includes a ninth lens 321 and a tenth lens 322 sequentially arranged from an object space to a second image space, the ninth lens 321 is a biconvex lens, the tenth lens 322 is a plano-concave lens, and the ninth lens 321 is cemented with the tenth lens 322; the sixth lens group 34 includes an eleventh lens 341, a twelfth lens 342, a second flat mirror 343, and a third flat mirror 344 sequentially arranged from the object side to the second image side, wherein the eleventh lens 341 is a biconvex lens, the twelfth lens 342 is a biconcave lens, and the eleventh lens 341 and the twelfth lens 342 are cemented together.
Specifically, the focal length f of the front-end lens group 1 and the focal length f1 of the first rear-end lens group 2 in the present embodiment preferably satisfy the condition that f1/f is 0.16, the focal length f of the front-end lens group 1 and the focal length f2 of the second rear-end lens group 3 preferably satisfy the condition that f2/f is 0.64, and the focal lengths f, f1 and f2 satisfy | (f1/f-0.16)/0.16| ≦ 10%, | (f2/f-0.64)/0.64| ≦ 10%, so that the measurement accuracy is higher, and the focal length range of the front-end lens group 1 is 180mm < f <280 mm. The focal length of the fifth lens group 32 is f3, and the focal length f3 needs to be larger than the focal length f2 of the second rear lens group 3, so as to increase the magnification.
The positions of the first diaphragm 21 and the second diaphragm 31 are set, the rear intercept of the front lens group 1 is fbl, and | (fbl-f)/f |, is less than or equal to 10%, so that the positions of the first diaphragm 21 and the second diaphragm 31 are limited, and the acquired field of view has uniform illumination and good brightness under the high-precision measurement condition.
The front lens group 1 has a structure: the first lens group 11 includes a first lens 111 and a second lens 112 arranged in sequence from an object side to a first image side, the first lens 111 is a plano-convex lens, the second lens 112 is a convex lens, a focal length of the first lens 111 is f5, a focal length of the second lens 112 is f6, an error condition that | f5/f6-1| is less than or equal to 10% is satisfied, and a larger visual field can be obtained by the front end lens group 1. When the plane of the beam splitter prism 12 at an angle of 45 ° has a transmittance T and a reflectance R, T and R satisfy T/R a (a 1, 2/3, 3/2.). Front end lens crowd 1 adopts heavy-calibre lens group to increase the field of vision, and the first rear end lens crowd 2 and the second rear end lens crowd 3 of setting different focuses again, and then form the light path of two bundles of different magnifications, wherein the demand in the big field of vision of a branch of multiplying power cooperation, another branch of demand that the setting through the lens module realized the high magnification, thereby can carry out the detection of different multiplying powers simultaneously, effectively improve detection efficiency, and satisfy the big and high multiplying power's in the field of vision demand.
Structurally, the beam splitter prism 12 splits the light beam of the front lens group 1 into two beams, the first beam is continuously the same as the optical axis of the front lens group 1, the second beam is perpendicular to the optical axis of the front lens group 1, if the second beam is not reflected any more, the second beam is perpendicular to the first beam, and the length of the second beam determines the length of the second lens, so that the problem of large volume of the whole lens due to the fact that the second lens is too long is easy to occur in the case; and increase the reflecting mirror 33 after the beam split of beam splitting prism 12, the reflectivity of reflecting mirror 33 is greater than 95%, reflecting mirror 33 reflects the second beam of light path, make two bunches of light paths parallel, has reduced the length of the second beam of light path, thus has reduced the length of the lens, has saved the volume of space, and then reduce the volume of the lens effectively, and when assembling structures such as CCD camera, because the lens is all in the same side, so make the assembly structure more simple and convenient. The double-magnification telecentric optical path can realize the effects of large visual field, high detection efficiency and small volume in the same lens.
In addition, the front end lens group 1, the first rear end lens group 2 and the second rear end lens group 3 are all made of optical glass with refractive index nd being larger than 1.6, and the lens can be guaranteed to have better telecentricity.
Although the present invention has been described with reference to the above preferred embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (8)
1. The utility model provides a telecentric optical path of double magnification which characterized in that: the system comprises a front end lens group, a first rear end lens group and a second rear end lens group;
the front-end lens group comprises a first lens group and a light splitting prism, wherein the first lens group and the light splitting prism are sequentially arranged from an object space to a first image space and have positive focal lengths;
the first rear lens group comprises a first diaphragm, a second lens group with a negative focal length, a third lens group with a negative focal length and a fourth lens group with a positive focal length which are sequentially arranged from the beam splitter prism to the first image space;
the second rear end lens group comprises a second diaphragm, a fifth lens group with positive focal length, a reflector and a sixth lens group with positive focal length, after light beams are split by the splitting prism, a part of the light beams sequentially pass through the second diaphragm, the fifth lens group, the reflector and the sixth lens group, and the optical axis of the sixth lens group is parallel to the optical axis of the first rear end lens group;
the focal length of the front lens group is f, the focal length of the first rear lens group is f1, the focal length of the second rear lens group is f2, and the focal lengths f, f1 and f2 satisfy
180mm<f<280mm，|(f1/f-0.16)/0.16|≤10％，|(f2/f-0.64)/0.64|≤10％。
2. A double-magnification telecentric optical system according to claim 1, wherein: the first lens group comprises a first lens and a second lens which are sequentially arranged from an object space to a first image space, the first lens is a plano-convex lens, and the second lens is a concave-convex lens.
3. A double-magnification telecentric optical system according to claim 1, wherein: the second lens group comprises a third lens and a fourth lens which are sequentially arranged from an object space to a first image space, the third lens is a concave-convex lens, the fourth lens is a concave-convex lens, and the third lens and the fourth lens are glued;
the third lens group comprises a fifth lens and a sixth lens which are sequentially arranged from an object space to a first image space, the fifth lens is a concave-convex lens, the sixth lens is a convex-concave lens, and the fifth lens is glued with the sixth lens;
the fourth lens group comprises a seventh lens, an eighth lens and a first plane mirror which are sequentially arranged from an object space to a first image space, the seventh lens is a biconvex lens, and the eighth lens is a biconvex lens.
4. A double-magnification telecentric optical system according to claim 1, wherein: the fifth lens group comprises a ninth lens and a tenth lens which are sequentially arranged from an object space to a second image space, the ninth lens is a biconvex lens, the tenth lens is a planoconcave lens, and the ninth lens and the tenth lens are glued;
the sixth lens group comprises an eleventh lens, a twelfth lens, a second plane mirror and a third plane mirror which are sequentially arranged from an object space to a second image space, wherein the eleventh lens is a biconvex lens, the twelfth lens is a biconcave lens, and the eleventh lens is glued with the twelfth lens.
5. A double-magnification telecentric optical system according to claim 1, wherein: if the focal length of the fifth lens group is f3, the focal length f3 satisfies: f2< f 3.
6. A double-magnification telecentric optical system according to claim 1, wherein: and if the rear intercept of the front-end lens group is fbl, the | (fb1-f)/f |, is less than or equal to 10%.
7. A double-magnification telecentric optical system according to claim 2, wherein: the focal length of the first lens is set as f5, the focal length of the second lens is set as f6, and the focal length f5 and the focal length f6 satisfy the following conditions: the | f5/f6-1| is less than or equal to 10 percent.
8. A double-magnification telecentric optical system according to claim 1, wherein: the front end lens group, the first rear end lens group and the second rear end lens group are all made of optical glass materials with refractive index nd larger than 1.6.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US5223974A (en) * | 1991-12-20 | 1993-06-29 | Itt Corporation | Collimator for binocular viewing system |
| CN203561788U (en) * | 2013-09-30 | 2014-04-23 | 东莞市普密斯精密仪器有限公司 | Double-amplification factor double-telecentric lens |
| CN106483642B (en) * | 2016-12-14 | 2023-05-09 | 舜宇光学(中山)有限公司 | Double telecentric lens based on machine vision |
| CN106950684B (en) * | 2017-04-13 | 2019-08-20 | 西安工业大学 | A kind of integrated infrared double-waveband 20X varifocal optical system |
| CN108345093A (en) * | 2018-03-23 | 2018-07-31 | 中国科学院西安光学精密机械研究所 | Shared aperture double-view field Dual band IR imaging lens |
| CN110221396A (en) * | 2019-07-17 | 2019-09-10 | 深圳市沃特隆科技有限公司 | A kind of novel telecentric lens structure |
| CN110646929A (en) * | 2019-09-30 | 2020-01-03 | 陕西维视数字图像技术有限公司 | Double-magnification large-field telecentric lens |
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