阅读说明：本技术 一种双远心镜头和光学器件 (Double telecentric lens and optical device ) 是由 白虎冰 赵飞 朱红伟 邱盛平 于 2021-08-11 设计创作，主要内容包括：本发明公开一种双远心镜头和光学器件,所述双远心镜头包括由物面到像面依次布置的前透镜组、光阑和后透镜组,本发明的技术方案中,通过前透镜组的像面和后透镜组的物面在光阑处重合,从而使得前透镜组、光阑和后透镜组三者之间构成一个双远心镜头,利用双远心镜头的高分辨率、低畸变等良好的光学特性,从而提升光学镜头在工业检测的领域的检测精度。(The invention discloses a double telecentric lens and an optical device, wherein the double telecentric lens comprises a front lens group, a diaphragm and a rear lens group which are sequentially arranged from an object plane to an image plane.)

1. The utility model provides a two telecentric mirror heads, its characterized in that, two telecentric mirror heads include by object plane to image plane preceding lens group, diaphragm and the back lens group that arranges in proper order, wherein, the image plane of preceding lens group with the object plane of back lens group is in diaphragm department coincidence.

2. The double telecentric lens of claim 1, wherein the front lens group comprises a first lens, a second lens, a third lens and a fourth lens arranged in order from the object plane to the image plane, wherein the focal power of the first lens is positive, the focal power of the second lens is positive, the focal power of the third lens is positive, and the focal power of the fourth lens is negative.

3. The double telecentric lens of claim 2, wherein the rear lens group comprises a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens arranged in order from the object plane to the image plane, wherein the power of the fifth lens is positive, the power of the sixth lens is positive, the power of the seventh lens is negative, the power of the eighth lens is positive, and the power of the ninth lens is positive.

4. A double telecentric lens according to claim 3, wherein the telecentricity of the double telecentric lens is less than 0.02%.

5. The double telecentric lens of claim 4, wherein the double telecentric lens is an athermal design.

6. The double telecentric lens system of claim 4, wherein the front lens group and/or the rear lens group each employ a spherical mirror.

7. The double telecentric lens of claim 5, wherein the distance between the front lens group and the object plane is between 99.5mm and 100.5 mm.

8. The double telecentric lens system of claim 7, wherein the object side telecentric front lens group and the image side telecentric rear lens group employ spherical mirrors, each lens having an object side object surface proximate to the object side object surface and an image side image surface proximate to the image side image surface;

the radius of an object side surface of the first lens is 153.5657mm, the thickness of the object side surface of the first lens is 8.0010mm, the radius of an image side surface of the first lens is-130.3873 mm, and the thickness of the image side surface of the first lens is 10.1251 mm;

the radius of an object side surface of the second lens is 53.1546mm, the thickness of the object side surface of the second lens is 11.3037mm, the radius of an image side surface of the second lens is 54.3410mm, and the thickness of the image side surface of the second lens is 9.9329 mm;

the radius of an object side surface of the third lens is 33.3306mm, the thickness of the object side surface of the third lens is 8.1880mm, the radius of an image side surface of the third lens is 49.5282mm, and the thickness of the image side surface of the third lens is 2.1393 mm;

the radius of the object side surface of the fourth lens is-34.7576 mm, the thickness of the object side surface of the fourth lens is 5.0003mm, and the radius of the image side surface of the fourth lens is 38.4613mm, and the thickness of the image side surface of the fourth lens is 3.8311 mm.

9. The double telecentric lens system of claim 8, wherein the object side telecentric front lens group and the image side telecentric rear lens group employ spherical mirrors, each lens having an object side object plane surface proximate to the object side object plane and an image side image plane surface proximate to the image side image plane,

the radius of an object side surface of the fifth lens is 46.3186mm, the thickness of the object side surface of the fifth lens is 3.5015mm, the radius of an image side surface of the fifth lens is-34.2055 mm, and the thickness of the image side surface of the fifth lens is 2.2179 mm;

the radius of an object side surface of the sixth lens is 75.9314mm, the thickness of the object side surface of the sixth lens is 3.5134mm, the radius of an image side surface of the sixth lens is-92.0444 mm, and the thickness of the image side surface of the sixth lens is 2.2900 mm;

the radius of an object side surface of the seventh lens is-29.8100 mm, the thickness of the object side surface of the seventh lens is 3.0000mm, the radius of an image side surface of the seventh lens is 40.0111mm, and the thickness of the image side surface of the seventh lens is 72.7125 mm;

the radius of an object side surface of the eighth lens is-122.6894 mm, the thickness of the eighth lens is 9.3174mm, the radius of an image side surface of the eighth lens is-68.8459 mm, and the thickness of the eighth lens is 1.5000 mm;

the radius of the object side surface of the eighth lens is 756.5312mm, the thickness of the object side surface of the eighth lens is 10.0004mm, the radius of the image side surface of the eighth lens is-175.2236 mm, and the thickness of the eighth lens is 140.0000 mm.

10. An optical device comprising a double telecentric lens according to any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of industrial detection, in particular to a double telecentric lens and an optical device.

Background

In industrial detection application, high-precision non-contact detection is often required to be carried out on an object, and a non-contact measurement method of optical imaging is used more, so that the requirement on the characteristics of an optical lens is higher, otherwise, the measurement result deviates from the actual situation due to the imaging error of an optical system, and the high-precision significance of the measurement is lost.

In the use process of a general industrial optical lens, due to adjustment deviation of an object distance, an imaging view field and a magnification ratio are changed, so that the view field and the magnification ratio of the lens are changed in the industrial detection process, and the situation has serious precision errors in the industrial detection process, needs to be solved by adopting an additional method or technology, and influences the use and detection efficiency. The uncertainty and complexity of detection results from the uncertainty of the object distance.

In industrial detection, for an environment with temperature which cannot meet detection requirements, the existing double telecentric lens has high requirements on the environment temperature and needs stable temperature conditions, for an environment with temperature change, the existing double telecentric lens rarely considers the environmental adaptability, and the performance of the lens can be rapidly reduced or even can not be used when the environmental requirements are not met.

Disclosure of Invention

The invention mainly aims to provide a double telecentric lens and aims to improve the detection precision of an optical lens in the field of industrial detection.

In order to achieve the above object, the present invention provides a double telecentric lens, which is characterized in that the double telecentric lens comprises a front lens group, a diaphragm and a rear lens group, which are sequentially arranged from an object plane to an image plane, wherein the image plane of the front lens group and the object plane of the rear lens group coincide at the diaphragm.

Preferably, the front lens group includes a first lens, a second lens, a third lens and a fourth lens, which are sequentially disposed from the object plane to the image plane, wherein focal power of the first lens is positive, focal power of the second lens is positive, focal power of the third lens is positive, and focal power of the fourth lens is negative.

Preferably, the rear lens group includes a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens, which are sequentially disposed from the object plane to the image plane, wherein a focal power of the fifth lens is positive, a focal power of the sixth lens is positive, a focal power of the seventh lens is negative, a focal power of the eighth lens is positive, and a focal power of the ninth lens is positive.

Preferably, the telecentricity of the double telecentric lens is less than 0.02%.

Preferably, the double telecentric lens adopts an athermal design.

Preferably, the front lens group and/or the rear lens group adopt spherical mirrors.

Preferably, the distance between the front lens group and the object plane is 99.5mm to 100.5 mm.

Preferably, the front lens group and the rear lens group adopt spherical mirrors, and each lens has an object side surface close to the object side object surface and an image side surface close to the image side image surface;

the radius of an object side surface of the first lens is 153.5657mm, the thickness of the object side surface of the first lens is 8.0010mm, the radius of an image side surface of the first lens is-130.3873 mm, and the thickness of the image side surface of the first lens is 10.1251 mm;

the radius of an object side surface of the second lens is 53.1546mm, the thickness of the object side surface of the second lens is 11.3037mm, the radius of an image side surface of the second lens is 54.3410mm, and the thickness of the image side surface of the second lens is 9.9329 mm;

the radius of an object side surface of the third lens is 33.3306mm, the thickness of the object side surface of the third lens is 8.1880mm, the radius of an image side surface of the third lens is 49.5282mm, and the thickness of the image side surface of the third lens is 2.1393 mm;

the radius of the object side surface of the fourth lens is-34.7576 mm, the thickness of the object side surface of the fourth lens is 5.0003mm, and the radius of the image side surface of the fourth lens is 38.4613mm, and the thickness of the image side surface of the fourth lens is 3.8311 mm.

Preferably, the object-side telecentric front lens group and the image-side telecentric rear lens group adopt spherical lenses, each lens has an object-side surface close to the object-side object surface and an image-side surface close to the image-side image surface,

the radius of an object side surface of the fifth lens is 46.3186mm, the thickness of the object side surface of the fifth lens is 3.5015mm, the radius of an image side surface of the fifth lens is-34.2055 mm, and the thickness of the image side surface of the fifth lens is 2.2179 mm;

the radius of an object side surface of the sixth lens is 75.9314mm, the thickness of the object side surface of the sixth lens is 3.5134mm, the radius of an image side surface of the sixth lens is-92.0444 mm, and the thickness of the image side surface of the sixth lens is 2.2900 mm;

the radius of an object side surface of the seventh lens is-29.8100 mm, the thickness of the object side surface of the seventh lens is 3.0000mm, the radius of an image side surface of the seventh lens is 40.0111mm, and the thickness of the image side surface of the seventh lens is 72.7125 mm;

the radius of an object side surface of the eighth lens is-122.6894 mm, the thickness of the eighth lens is 9.3174mm, the radius of an image side surface of the eighth lens is-68.8459 mm, and the thickness of the eighth lens is 1.5000 mm;

the radius of the object side surface of the eighth lens is 756.5312mm, the thickness of the object side surface of the eighth lens is 10.0004mm, the radius of the image side surface of the eighth lens is-175.2236 mm, and the thickness of the eighth lens is 140.0000 mm.

To achieve the above object, the present application further provides an optical device including a double telecentric lens according to any one of the above items.

According to the technical scheme, the image surface of the front lens group and the object surface of the rear lens group are overlapped at the diaphragm, so that a double telecentric lens is formed among the front lens group, the diaphragm and the rear lens group, and the detection precision of the optical lens in the field of industrial detection is improved by utilizing good optical characteristics of high resolution, low distortion and the like of the double telecentric lens.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an embodiment of a double telecentric lens provided by the present invention;

fig. 2 is an MTF plot at 0 ℃ for the double telecentric lens of fig. 1;

fig. 3 is an MTF plot at 20 ℃ for the double telecentric lens of fig. 1;

fig. 4 is an MTF plot at 60 ℃ for the double telecentric lens of fig. 1.

The reference numbers illustrate:

the implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative positional relationship between the components, the movement situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" appearing throughout includes three juxtapositions, exemplified by "A and/or B" including either A or B or both A and B. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

In industrial detection application, high-precision non-contact detection is often required to be directly performed on form and position parameter substances of a measured object, and a non-contact measurement method of optical imaging is often adopted for measurement, so that the requirement on the characteristics of an optical lens is high, otherwise, the measurement result is reduced and deviates from the actual situation due to imaging errors of an optical system, and high-precision significance is lost due to the fact that data processing is difficult to perform.

In the use process of a general industrial optical lens, due to adjustment deviation of an object distance, an imaging view field and magnification are changed, and in the case, the view field and magnification of the lens are changed in the industrial detection process, so that a serious precision error exists in the use process of industrial detection, an additional method or technology is required to solve the problem, and the use and detection efficiency is influenced. The uncertainty and complexity of detection results from the uncertainty of the object distance.

In industrial detection, for an environment with temperature which cannot meet detection requirements, the existing double telecentric lens has high requirements on the environment temperature and needs stable temperature conditions, for an environment with temperature change, the existing double telecentric lens rarely considers the environmental adaptability, and the performance of the lens can be rapidly reduced or even can not be used when the environmental requirements are not met.

In view of the above, the present invention provides a double telecentric lens 100 and an optical device, and fig. 1 is a schematic structural diagram of an embodiment of the double telecentric lens provided by the present invention; fig. 2 is an MTF plot at 0 ℃ for the double telecentric lens of fig. 1; fig. 3 is an MTF plot at 20 ℃ for the double telecentric lens of fig. 1; fig. 4 is an MTF graph of the double telecentric lens of fig. 1 at 60 ℃, please refer to fig. 1 to 4.

The double telecentric lens 100 comprises a front lens group 10, a diaphragm 20 and a rear lens group 30 which are sequentially arranged from an object plane 40 to an image plane 50, wherein the image plane of the front lens group 10 and the object plane of the rear lens group 30 coincide at the diaphragm 20.

In the technical scheme of the invention, the image plane of the front lens group 10 and the object plane of the rear lens group 30 are overlapped at the diaphragm 20, so that a double telecentric lens 100 is formed among the front lens group 10, the diaphragm 20 and the rear lens group 30, and the detection precision of the optical lens in the field of industrial detection is improved by utilizing the good optical characteristics of high resolution, low distortion and the like of the double telecentric lens 100.

Further, when the incident angle of light is large, the detection effect is poor, the front lens group 10 includes a first lens 11, a second lens 12, a third lens 13 and a fourth lens 14, which are sequentially disposed from the object plane 40 to the image plane 50, where the focal power of the first lens 11 is positive, the focal power of the second lens 12 is positive, the focal power of the third lens 13 is positive, and the focal power of the fourth lens 14 is negative, and by setting the first three lenses of the front lens group 10 to positive focal power, some light rays with large incident angles can be converged on the fourth lens 14, and then by refraction of the fourth lens 14, the light rays are converged on the diaphragm 20, and the focal power of the first lens 11 is 0.0108-0.0125, and the refractive index of the second lens 12 is greater than 1.8.

Still further, the rear lens group 30 includes a fifth lens 31, a sixth lens 32, a seventh lens 33, an eighth lens 34, and a ninth lens 35, which are sequentially disposed from the object plane 40 to the image plane 50, wherein a focal power of the fifth lens 31 is positive, a focal power of the sixth lens 32 is positive, a focal power of the seventh lens 33 is negative, a focal power of the eighth lens 34 is positive, and a focal power of the ninth lens 35 is positive. The front lens group 10 and/or the rear lens group 30 are spherical mirrors, the refractive power of the ninth lens 35 is 0.004 to 0.006, and the refractive index of the sixth lens 32 and the refractive index of the seventh lens 33 are greater than 1.7.

In addition, in order to meet the requirement of measurement accuracy and ensure distortion, the telecentricity of the double telecentric lens 100 is less than 0.02%, and specifically, the clear aperture of the diaphragm can be adjusted to meet the telecentricity requirement of the whole optical system.

Further, in the conventional optical lens, due to temperature rise or change of ambient temperature caused by light source irradiation, the lens has large performance reduction, cannot be used and has poor stability. In order to ensure the stability of the double telecentric lens 100 of the present application in different temperature environments, the double telecentric lens 100 in the present application adopts an athermal design.

The following table lists data for a specific example:

the numbers of the surfaces in the upper table refer to, from the object plane 40 to the image plane 50 in fig. 1, it can be understood that S1 refers to the surface of the first lens 11 close to the object plane 40, S2 refers to the surface of the first lens 11 close to the image plane 50, S3 refers to the surface of the second lens 12 close to the object plane 40, S4 refers to the surface of the second lens 12 close to the image plane 50, and so on, each reference number represents a surface.

The double telecentric lens 100 adopts an athermalization design, and the matching of the materials ensures that the double telecentric lens 100 has relatively excellent stability in different temperature environments, please refer to fig. 2 to 4, and it can be clearly seen from the figures that the performance of the double telecentric lens 100 is very stable and has excellent stability in the environment temperature of 0 ℃ to 60 ℃ in the double telecentric lens 100 of the present application.

Moreover, the front lens group 10 can have a larger depth of field under the condition of fixing the object distance, and multiple experiments prove that when the distance between the front lens group 10 and the object plane 40 is 99.5 mm-100.5 mm, the magnification of the lens is 1.825-1.83, the depth of field is the largest, the detection effect is the best, and the imaging distortion can be ensured to be less than 0.005%.

Further, the front lens group 10 and the rear lens group 30 employ spherical mirrors, each having an object side 40 surface close to the object side 40 and an image side image surface 50 surface close to the image side image surface 50; the radius of the object side 40 surface of the first lens 11 is 153.5657mm, the thickness of the object side 40 surface is 8.0010mm, the radius of the image side 50 surface of the first lens 11 is-130.3873 mm, and the thickness of the image side 50 surface of the first lens 11 is 10.1251 mm; the radius of the object side 40 surface of the second lens 12 is 53.1546mm, the thickness of the object side 40 surface is 11.3037mm, the radius of the image side 50 surface of the second lens 12 is 54.3410mm, and the thickness of the image side 50 surface of the second lens 12 is 9.9329 mm; the radius of the object side 40 surface of the third lens 13 is 33.3306mm, the thickness of the object side 40 surface is 8.1880mm, the radius of the image side 50 surface of the third lens 13 is 49.5282mm, and the thickness of the image side 50 surface of the third lens 13 is 2.1393 mm; the radius of the object side 40 surface of the fourth lens 14 is-34.7576 mm, the thickness of the object side 40 surface is 5.0003mm, and the radius of the image side 50 surface of the fourth lens 14 is 38.4613mm, and the thickness of the image side 50 surface is 3.8311 mm. The object-side telecentric front lens group 10 and the image-side telecentric rear lens group 30 are spherical lenses, each lens has an object-side object surface 40 close to the object-side object surface 40 and an image-side image surface 50 close to the image-side image surface 50, the radius of the object-side object surface 40 of the fifth lens 31 is 46.3186mm, the thickness of the object-side object surface is 3.5015mm, the radius of the image-side image surface 50 of the fifth lens 31 is-34.2055 mm, and the thickness of the image-side image surface is 2.2179 mm; the radius of an object side 40 surface of the sixth lens 32 is 75.9314mm, the thickness of the object side 40 surface is 3.5134mm, the radius of an image side 50 surface of the sixth lens 32 is-92.0444 mm, and the thickness of the image side 50 surface is 2.2900 mm; the radius of the object-side surface 40 of the seventh lens element 33 is-29.8100 mm, the thickness of the seventh lens element 33 is 3.0000mm, and the radius of the image-side surface 50 of the seventh lens element 33 is 40.0111mm, the thickness of the seventh lens element 33 is 72.7125 mm; the radius of the object-side object surface 40 of the eighth lens 34 is-122.6894 mm, the thickness of the object-side object surface is 9.3174mm, the radius of the image-side image surface 50 of the eighth lens 34 is-68.8459 mm, and the thickness of the image-side image surface is 1.5000 mm; the radius of the object side 40 surface of the eighth lens 34 is 756.5312mm, the thickness of the object side 40 surface of the eighth lens 34 is 10.0004mm, the radius of the image side image surface 50 surface of the eighth lens 34 is-175.2236 mm, the thickness of the image side image surface of the eighth lens is 140.0000mm, the double telecentric lens 100 can achieve the telecentricity within the range of 0.02%, the distortion is less than 0.005%, the maximum deviation of the field curvature is less than 100 mu m, and the diameter of a circle of confusion of the lens is 0.005 mm.

To achieve the above object, the present application further proposes an optical device comprising a double telecentric lens 100 according to any one of the above items.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.