CN110198794B

CN110198794B - Laser cleaning lens

Info

Publication number: CN110198794B
Application number: CN201780084415.3A
Authority: CN
Inventors: 李家英; 孙博; 陈根余; 陈焱; 高云峰
Original assignee: Han s Laser Technology Industry Group Co Ltd
Current assignee: Han s Laser Technology Industry Group Co Ltd
Priority date: 2017-06-01
Filing date: 2017-06-01
Publication date: 2022-02-18
Anticipated expiration: 2037-06-01
Also published as: WO2018218605A1; CN110198794A

Abstract

A laser cleaning lens comprises a first lens (100), a second lens (200), a third lens (300) and a fourth lens (400) which are arranged in sequence from an object side to an image side. The first lens (100) is a meniscus lens, the second lens (200) is a meniscus lens, the third lens (300) is a meniscus lens, and the fourth lens (400) is a plano-concave lens. The fourth lens (400) can move towards the direction close to or away from the third lens (300).

Description

Laser cleaning lens

Technical Field

The invention relates to a laser cleaning lens.

Background

Laser cleaning has the cleaning characteristics of no grinding, no contact, no thermal effect and the like, and is increasingly applied to industrial cleaning. During cleaning, light spots formed on the surface of a workpiece by the laser cleaning lens are in a strip shape, and the length of the light spots is related to the focal length of the laser cleaning lens. Generally, the focal length of the laser cleaning lens is a certain value, and for different cleaning ranges, that is, different spot lengths, the laser cleaning lens with different focal lengths needs to be used. The preparation of various laser cleaning lenses is not only troublesome, but also increases the production cost of the laser cleaning lenses.

Disclosure of Invention

Based on this, it is necessary to provide a focus adjustable laser cleaning lens.

A laser cleaning lens comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged from an object side to an image side, wherein the first lens is a meniscus lens, the second lens is a meniscus lens, the third lens is a meniscus lens, the fourth lens is a plano-concave lens, and the fourth lens can move towards a direction close to or far away from the third lens.

According to the laser cleaning lens, the fourth lens can move towards the direction close to or away from the third lens, namely the distance between the third lens and the fourth lens is adjustable, so that the focal length of the laser cleaning lens can be changed. Accordingly, the length of the light spot formed on the surface of the workpiece by the laser cleaning lens is changed along with the change of the focal length. Therefore, the laser cleaning lens can meet the requirements of different cleaning ranges, is very convenient, and can reduce the production cost of the laser cleaning 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 of the embodiments can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a laser cleaning lens according to an embodiment;

FIG. 2 is a geometric aberration diagram of the laser cleaning lens shown in FIG. 1;

fig. 3 is a graph of the optical transfer function of the laser cleaning lens shown in fig. 1.

Detailed Description

To facilitate an understanding of the present invention, a laser cleaning lens will be described more fully below with reference to the accompanying drawings. The preferred embodiments of the laser cleaning lens are shown in the drawings. However, the laser cleaning lens may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the laser cleaning lens herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Fig. 1 is a schematic structural diagram of a laser cleaning lens according to an embodiment, and only a part related to the embodiment is shown for convenience of description.

As shown in fig. 1, a laser cleaning lens according to one embodiment of the present disclosure includes a first lens element 100, a second lens element 200, a third lens element 300, a fourth lens element 400, and a fifth lens element 500, which are arranged in order from an object side to an image side (in an arrow direction in fig. 1). The first lens element 100 is a meniscus lens element, the second lens element 200 is a meniscus lens element, the third lens element 300 is a meniscus lens element, the fourth lens element 400 is a plano-concave lens element, and the fifth lens element 500 is a planar lens element. The first lens 100, the second lens 200, the third lens 300, and the fourth lens 400 mainly perform a focusing function, and the fifth lens 500 performs a protective function, so that the fourth lens 400 can be prevented from being contaminated or damaged by scattering of debris generated during a cleaning process, and in other embodiments, the fifth lens 500 may be omitted.

In the present embodiment, the fourth lens 400 can move in a direction to approach or separate from the third lens 300. That is, the distance between the third lens 300 and the fourth lens 400 is adjustable, so that the focal length of the laser cleaning lens can be changed, and accordingly, the length of a light spot formed on the surface of a workpiece by the laser cleaning lens is changed along with the change of the focal length. Therefore, the laser cleaning lens can meet the requirements of different cleaning ranges, is very convenient, and can reduce the production cost of the laser cleaning lens.

In the laser cleaning lens, with the viewing angle shown in fig. 1, infrared rays having a wavelength of 1064nm travel from left to right, and the workpiece is located on the right side of the fifth lens 500. With the intersection point of the spherical surface and the optical axis 600 as the standard, the spherical center of the spherical surface is on the left of the intersection point, the curvature radius of the spherical surface is negative, and the spherical center of the spherical surface is on the right of the intersection point, the curvature radius of the spherical surface is positive. That is, the positive and negative independent magnitudes of the radius of curvature represent only the direction of curvature of the spherical surface.

The first lens 100 includes a first surface 110 and a second surface 120 arranged in a direction from an object side to an image side. The first face 110 is convex toward the right with a radius of curvature of-15 mm to-55 mm. The second face 120 is convex to the right with a radius of curvature of-16 mm to-45 mm. The center thickness of the first lens 100 (i.e., the thickness of the first lens 100 on the optical axis 600) is 4.8mm to 10.2 mm. The ratio of the refractive index to the abbe number of the first lens 100 is 1.46/67.

The second lens 200 includes a third surface 210 and a fourth surface 220 arranged from the object side to the image side. The third face 210 is convex toward the right and has a radius of curvature of-95 mm to-200 mm. The fourth surface 220 protrudes to the right, the radius of curvature of the fourth surface 220 is less than or equal to the radius of curvature of the third surface 210, and the radius of curvature of the fourth surface 220 is-50 mm to-95 mm. The center thickness of the second lens 200 is 5.2mm to 10 mm. The ratio of the refractive index to the abbe number of the second lens 200 is 1.80/25.

The third lens 300 includes a fifth surface 310 and a sixth surface 320 arranged from the object side to the image side. The fifth surface 310 is convex towards the right and has a radius of curvature of-202 mm to-283 mm. The sixth surface 320 is convex towards the right, and has a radius of curvature smaller than that of the fifth surface 310, and the radius of curvature of the sixth surface 320 is-101 mm to-133 mm. The third lens 300 has a center thickness of 3.3mm to 9.6 mm. The ratio of the refractive index to the abbe number of the third lens 300 is 1.80/25.

The fourth lens 400 includes a seventh surface 410 and an eighth surface 420 arranged in the direction from the object side to the image side. The seventh surface 410 is convex toward the right and has a radius of curvature of-64 mm to-104 mm. The eighth surface 420 is a plane perpendicular to the optical axis 600, and the radius of curvature of the eighth surface 420 is ∞. The center thickness of the fourth lens 400 is 0.5mm to 5.5 mm. The ratio of the refractive index to the abbe number of the fourth lens 400 is 1.50/62.

The fifth lens 500 includes a ninth surface 510 and a tenth surface 520 arranged in the image-side direction from the object side. The ninth surface 510 is a plane surface having a radius of curvature of ∞. The tenth surface 520 is a plane having a radius of curvature of ∞. The fifth lens 500 has a central thickness of 0.8mm to 5.6 mm. The ratio of the refractive index to the abbe number of the fifth lens 500 is 1.50/62.

In the present embodiment, the positions of the first lens 100, the second lens 200, and the third lens 300 are fixed, and the pitch between the second surface 120 and the third surface 210 (which refers to the distance between the intersection of the second surface 120 and the optical axis 600 and the intersection of the third surface 210 and the optical axis 600, and the same applies hereinafter) is 0.3mm to 4mm, and the pitch between the fourth surface 220 and the fifth surface 310 is 0.1mm to 2.2 mm. The distance between the sixth surface 320 and the seventh surface 410 can be varied within a range of 7mm to 46mm when the fourth lens 400 is moved.

The laser cleaning lens of the present embodiment is an f-theta lens, and the entrance pupil size is 10 mm. When the fourth lens 400 is moved such that the distance between the sixth surface 320 and the seventh surface 410 is changed within a range of 7mm to 46mm, the focal length of the laser cleaning lens is changed within a range of 160mm to 254mm, the working distance is changed within a range of 98mm to 244mm, and the length of the spot is changed within a range of 144mm to 220 mm. Therefore, the laser cleaning lens of the embodiment can meet the requirements of different cleaning ranges.

With reference to fig. 2 and fig. 3, when the resolution reaches 20line/mm, the MTF of the laser cleaning lens is still greater than 0.3, and the ideal effect is achieved. No matter the geometric aberration or the optical transfer function is adopted, the laser cleaning lens is very ideal in correction, and the laser cleaning effect can be guaranteed.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A laser cleaning lens comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged from an object side to an image side, wherein the first lens is a meniscus lens, the second lens is a meniscus lens, the third lens is a meniscus lens, the fourth lens is a plano-concave lens, the fourth lens can move towards a direction close to or far away from the third lens, the third lens comprises a fifth surface and a sixth surface, the fourth lens comprises a seventh surface and an eighth surface, and the distance between the sixth surface and the seventh surface can be changed within the range from 7mm to 46 mm.

2. The laser cleaning lens according to claim 1, wherein the first lens includes a first surface and a second surface, the second lens includes a third surface and a fourth surface, and the first surface to the eighth surface are arranged in order from the object side to the image side.

3. The laser cleaning lens according to claim 2, wherein the second surface is spaced from the third surface by 0.3mm to 4mm, and the fourth surface is spaced from the fifth surface by 0.1mm to 2.2 mm.

4. The laser cleaning lens according to claim 2, wherein a radius of curvature of the third surface is equal to or greater than a radius of curvature of the fourth surface, and a radius of curvature of the fifth surface is greater than a radius of curvature of the sixth surface.

5. The laser cleaning lens according to claim 2, wherein the radius of curvature of the first surface is-15 mm to-55 mm, the radius of curvature of the second surface is-16 mm to-45 mm, the radius of curvature of the third surface is-95 mm to-200 mm, the radius of curvature of the fourth surface is-50 mm to-95 mm, the radius of curvature of the fifth surface is-202 mm to-283 mm, the radius of curvature of the sixth surface is-101 mm to-133 mm, the radius of curvature of the seventh surface is-64 mm to-104 mm, and the radius of curvature of the eighth surface is ∞.

6. The laser cleaning lens according to claim 1, wherein the first lens has a center thickness of 4.8mm to 10.2mm, the second lens has a center thickness of 5.2mm to 10mm, the third lens has a center thickness of 3.3mm to 9.6mm, and the fourth lens has a center thickness of 0.5mm to 5.5 mm.

7. The laser cleaning lens according to claim 1, wherein the ratio of the refractive index to the abbe number of the first lens is 1.46/67, the ratio of the refractive index to the abbe number of the second lens is 1.80/25, the ratio of the refractive index to the abbe number of the third lens is 1.80/25, and the ratio of the refractive index to the abbe number of the fourth lens is 1.50/62.

8. The laser cleaning lens according to claim 1, further comprising a fifth lens element, the first to fifth lens elements being arranged in order from the object side to the image side, the fifth lens element being a planar lens element, the fifth lens element including a ninth surface and a tenth surface, the ninth surface being located between the fourth lens element and the tenth surface, a radius of curvature of the ninth surface being ∞, and a radius of curvature of the tenth surface being ∞.

9. The laser cleaning lens according to claim 8, wherein the fifth lens has a center thickness of 0.8mm to 5.6 mm.

10. The laser cleaning lens according to claim 8, wherein a ratio of a refractive index to an abbe number of the fifth lens is 1.50/62.