A cylindrical line spot lens with small focal depth and long working distance

Abstract

The present invention relates to the field of high-precision laser processing technology, and in particular to a cylindrical line spot lens with a small focal depth and a long working distance, comprising a cylindrical line spot lens body, wherein the cylindrical line spot lens body comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens, wherein the first lens, the second lens, the third lens, the fourth lens and the fifth lens are all arranged in a cylindrical lens structure, wherein two sides of the first lens are respectively a first object side surface and a first image side surface, two sides of the second lens are respectively a second object side surface and a second image side surface, two sides of the third lens are respectively a third object side surface and a third image side surface, two sides of the fourth lens are respectively a fourth object side surface and a fourth image side surface, and two sides of the fifth lens are respectively a fifth object side surface and a fifth image side surface. The present invention solves the problem that although a traditional line scanning lens can provide continuous line scanning, its focal depth is large, which limits its application in high-precision polishing.

Description

Technical Field

[0001] The present invention relates to the technical field of high-precision laser processing, and in particular to a cylindrical line spot lens with a small focal depth and a long working distance. Background Art

[0002] Light is everywhere around us, and high-precision laser processing technology is also inseparable from our lives, such as various cameras, video cameras, telescopes, projectors, etc. In high-precision laser processing, the requirements for processing accuracy are getting higher and higher.

[0003] In the prior art, a Chinese patent application numbered CN202022933017.6 discloses a reverse telephoto lens, a reverse telephoto system, and a scanning device. Along the optical axis from the object side to the image side, the reverse telephoto lens includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens in sequence; the reverse telephoto ratio of the reverse telephoto lens has a value range of [7.40, 7.80]. The reverse telephoto lens of the embodiment of the present application has a large reverse telephoto ratio and has a strong converging effect on the light beam passing through the reverse telephoto lens. When used with a laser, it can significantly increase the optical power density of the laser, so that the laser can increase the illumination light under a limited maximum power.

[0004] In the above technical solution, the focal length is 20-40mm, the working distance is 155-298mm, and the reflection-to-reflection ratio is 7.4-7.8. However, its too long working distance makes it difficult to achieve a small focal depth and it is difficult to meet the requirements of high-precision laser polishing. Although traditional line scan lenses can provide continuous line scanning, their focal depth is large, which limits their application in high-precision polishing. For this reason, we propose a cylindrical line spot lens with a small focal depth and a long working distance. Summary of the Invention

[0005] The purpose of the present invention is to address the shortcomings of the prior art and to propose a cylindrical line spot lens with a small focal depth and a long working distance. This cylindrical line spot lens with a small focal depth and a long working distance solves the problem that although traditional line scanning lenses can provide continuous line scanning, their focal depth is large, which limits their application in high-precision polishing.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A cylindrical line spot lens with a small focal depth and a long working distance, comprising a cylindrical line spot lens body, the cylindrical line spot lens body comprising a first lens element, a second lens element, a third lens element, a fourth lens element, and a fifth lens element, wherein the first lens element, the second lens element, the third lens element, the fourth lens element, and the fifth lens element are all arranged in a cylindrical lens structure, the first lens element has two sides respectively forming a first object side surface and a first image side surface, the second lens element has two sides respectively forming a second object side surface and a second image side surface, the third lens element has two sides respectively forming a third object side surface and a third image side surface, the fourth lens element has two sides respectively forming a fourth object side surface and a fourth image side surface, and the fifth lens element has two sides respectively forming a fifth object side surface and a fifth image side surface;

[0008] The first object-side surface is a concave surface, and the first image-side surface is a convex surface;

[0009] The second object-side surface is a concave surface, and the second image-side surface is a convex surface;

[0010] The third object-side surface is a concave surface, and the third image-side surface is a convex surface;

[0011] The fourth object-side surface is a convex surface, and the fourth image-side surface is a convex surface;

[0012] The fifth object-side surface is a convex surface, and the fifth image-side surface is a concave surface.

[0013] Preferably, the curvature radius of the first object-side surface in the vertical direction is 8-17 mm, and the curvature radius of the first image-side surface in the vertical direction is 16-26 mm;

[0014] The curvature radius of the second object-side surface in the vertical direction is 64-75 mm, and the curvature radius of the second image-side surface in the vertical direction is 18-27 mm;

[0015] The curvature radius of the third object-side surface in the vertical direction is 9-18 mm, and the curvature radius of the third image-side surface in the vertical direction is 17-27 mm;

[0016] The curvature radius of the fourth object-side surface in the vertical direction is 23-33 mm, and the curvature radius of the fourth image-side surface in the vertical direction is 65-80 mm;

[0017] The curvature radius of the fifth object side surface in the vertical direction is 9-18 mm, and the curvature radius of the fifth image side surface in the vertical direction is 60-70 mm.

[0018] Preferably, the curvature radius of the first object-side surface in the vertical direction is 12.9±0.01 mm, and the curvature radius of the first image-side surface in the vertical direction is 21.3±0.01 mm;

[0019] The radius of curvature of the second object-side surface in the vertical direction is 69.9±0.01 mm, and the radius of curvature of the second image-side surface in the vertical direction is 22.7±0.01 mm;

[0020] The curvature radius of the third object-side surface in the vertical direction is 13.1±0.01 mm, and the curvature radius of the third image-side surface in the vertical direction is 22.5±0.01 mm;

[0021] The radius of curvature of the fourth object-side surface in the vertical direction is 28.3±0.01 mm, and the radius of curvature of the fourth image-side surface in the vertical direction is 71.9±0.01 mm;

[0022] The curvature radius of the fifth object-side surface in the vertical direction is 13.7±0.01 mm, and the curvature radius of the fifth image-side surface in the vertical direction is 65.3±0.01 mm.

[0023] Preferably, the refractive index of the first lens, the second lens, the third lens, the fourth lens and the fifth lens are all between 1.37-2.0, and the Abbe constant is all between 30-85.

[0024] Preferably, the first lens, the second lens, the third lens, the fourth lens and the fifth lens are all made of BK7, K9 or fused quartz components.

[0025] Preferably, the center distance between the first lens and the second lens is 50-56 mm, the center distance between the second lens and the third lens is 3-5 mm, the center distance between the third lens and the fourth lens is 0.1-0.3 mm, and the center distance between the fourth lens and the fifth lens is 3-4 mm.

[0026] Preferably, the center thickness of the first lens is 5-9 mm, the center thickness of the second lens is 7-11 mm, the center thickness of the third lens is 7-10 mm, the center thickness of the fourth lens is 3-6 mm, and the center thickness of the fifth lens is 5-8 mm.

[0027] Preferably, the outer diameter of the first lens is 16-24 mm, the outer diameter of the second lens is 20-26 mm, the outer diameter of the third lens is 20-26 mm, the outer diameter of the fourth lens is 20-26 mm, and the outer diameter of the fifth lens is 20-26 mm.

[0028] Preferably, a reflective lens is provided on the upper side of the cylindrical line spot lens body, and the reflective lens includes a first reflective lens and a second reflective lens. A collimating lens and an infinite imaging lens are provided on the upper side of the reflective lens. A CCD camera is provided on the upper side of the infinite imaging lens. An adjustable tilt stage is provided on the lower side of the cylindrical line spot lens body.

[0029] Preferably, the adjustable tilt platform includes an upper plate and a lower plate, and the upper plate and the lower plate are arranged in a parallel and symmetrical structure. A tilt adjustment screw 1 and a tilt adjustment screw 2 are respectively provided at the corners between the upper plate and the lower plate. The tilt adjustment screw 1 and the tilt adjustment screw 2 are arranged in a diagonal structure. A plurality of cylindrical pins are provided on the upper side of the upper plate and the lower side of the lower plate, and a tension spring is provided between two of the cylindrical pins.

[0030] In summary, the present invention provides high-precision laser processing with a small focal depth by setting a cylindrical line spot lens body, reduces laser polishing errors, and provides a longer working distance, which is suitable for high-precision laser processing in complex environments and objects.

[0031] The present invention can provide a function of adjusting the uniformity of the beam of a cylindrical line light spot to the cylindrical line light spot lens body by arranging a collimating lens, a CCD camera, an infinite imaging lens, a reflecting lens and an adjustable tilt platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the optical path of the cylindrical line spot lens body of the present invention;

[0033] Figure 2 Schematic diagram of focusing of the cylindrical line spot lens body of the present invention;

[0034] Figure 3 Schematic diagram of the line spot of the cylindrical line spot lens body on the focal plane of the present invention;

[0035] Figure 4 Schematic diagram of the normalized energy value (ordinate) and size (abscissa) of the line spot in the X and Y directions on the focal plane of the present invention;

[0036] Figure 5 This is the defocus FFT MTF diagram of the cylindrical line spot lens body of the present invention;

[0037] Figure 6 This is a schematic diagram of the assembled structure of the present invention;

[0038] Figure 7 It is a structural schematic diagram of the assembled cross-section of the present invention;

[0039] Figure 8 This is a schematic diagram of the front axial structure of the adjustable tilt platform of the present invention;

[0040] Figure 9 It is a schematic diagram of the top structure of the adjustable tilting platform of the present invention.

[0041] In the figure: 500, cylindrical line spot lens body; 1, first lens; 2, second lens; 3, third lens; 4, fourth lens; 5, fifth lens; 100, collimating lens; 200, CCD camera; 300, infinity imaging lens; 400, reflecting lens; 401, first reflecting lens; 402, second reflecting lens; 600, adjustable tilt platform; 601, upper plate; 602, lower plate; 603, tilt adjustment screw 1; 604, tilt adjustment screw 2; 605, tension spring; 606, cylindrical pin. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0043] like Figure 1 As shown, a cylindrical line spot lens with a small focal depth and a long working distance includes a cylindrical line spot lens body 500, which includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a fifth lens 5. The first lens 1, the second lens 2, the third lens 3, the fourth lens 4, and the fifth lens 5 are all arranged in a cylindrical lens structure and arranged along the incident direction of light. The refractive index of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, and the fifth lens 5 are all between 1.37 and 2.0, and the Abbe constant is all between 30 and 85. The first lens 1, the second lens 2, the third lens 3, the fourth lens 4, and the fifth lens 5 are all made of BK7, K9, or fused quartz components.

[0044] The center distance between the first lens 1 and the second lens 2 is 50-56mm, the center distance between the second lens 2 and the third lens 3 is 3-5mm, the center distance between the third lens 3 and the fourth lens 4 is 0.1-0.3mm, and the center distance between the fourth lens 4 and the fifth lens 5 is 3-4mm. The center thickness of the first lens 1 is 5-9mm, the center thickness of the second lens 2 is 7-11mm, the center thickness of the third lens 3 is 7-10mm, the center thickness of the fourth lens 4 is 3-6mm, and the center thickness of the fifth lens 5 is 5-8mm. The outer diameter of the first lens 1 is 16-24mm, the outer diameter of the second lens 2 is 20-26mm, the outer diameter of the third lens 3 is 20-26mm, the outer diameter of the fourth lens 4 is 20-26mm, and the outer diameter of the fifth lens 5 is 20-26mm.

[0045] The two sides of the first lens 1 are the first object side surface and the first image side surface respectively, the two sides of the second lens 2 are the second object side surface and the second image side surface respectively, the two sides of the third lens 3 are the third object side surface and the third image side surface respectively, the two sides of the fourth lens 4 are the fourth object side surface and the fourth image side surface respectively, and the two sides of the fifth lens 5 are the fifth object side surface and the fifth image side surface respectively,

[0046] The first object side surface is concave, the first image side surface is convex, the curvature radius of the first object side surface in the vertical direction is 8-17 mm, the curvature radius of the first image side surface in the vertical direction is 16-26 mm, the curvature radius of the first object side surface in the vertical direction is 12.9±0.01 mm, and the curvature radius of the first image side surface in the vertical direction is 21.3±0.01 mm.

[0047] The second object side surface is concave, the second image side surface is convex, the curvature radius of the second object side surface in the vertical direction is 64-75mm, the curvature radius of the second image side surface in the vertical direction is 18-27mm, the curvature radius of the second object side surface in the vertical direction is 69.9±0.01mm, and the curvature radius of the second image side surface in the vertical direction is 22.7±0.01mm.

[0048] The third object side surface is concave, the third image side surface is convex, the curvature radius of the third object side surface in the vertical direction is 9-18mm, the curvature radius of the third image side surface in the vertical direction is 17-27mm, the curvature radius of the third object side surface in the vertical direction is 13.1±0.01mm, and the curvature radius of the third image side surface in the vertical direction is 22.5±0.01mm.

[0049] The fourth object side surface is convex, the fourth image side surface is convex, the curvature radius of the fourth object side surface in the vertical direction is 23-33 mm, the curvature radius of the fourth image side surface in the vertical direction is 65-80 mm, the curvature radius of the fourth object side surface in the vertical direction is 28.3±0.01 mm, and the curvature radius of the fourth image side surface in the vertical direction is 71.9±0.01 mm.

[0050] The fifth object side surface is convex, the fifth image side surface is concave, the curvature radius of the fifth object side surface in the vertical direction is 9-18 mm, the curvature radius of the fifth image side surface in the vertical direction is 60-70 mm, the curvature radius of the fifth object side surface in the vertical direction is 13.7±0.01 mm, and the curvature radius of the fifth image side surface in the vertical direction is 65.3±0.01 mm.

[0051] like Figure 6-Figure 9As shown, a reflective lens 400 is provided on the upper side of the cylindrical line spot lens body 500. The reflective lens 400 includes a first reflective lens 401 and a second reflective lens 402. The reflection angle of the first reflective lens 401 and the second reflective lens 402 is 45 degrees. A collimating lens 100 and an infinite imaging lens 300 are provided on the upper side of the reflective lens 400. A CCD camera 200 is provided on the upper side of the infinite imaging lens 300. An adjustable tilting platform 600 is provided on the lower side of the cylindrical line spot lens body 500. The adjustable tilting platform 600 includes an upper plate 601 and the lower plate 602, the upper plate 601 and the lower plate 602 are arranged in a parallel and symmetrical structure, and a tilt adjustment screw 1 603 and a tilt adjustment screw 2 604 are respectively provided at the corners between the upper plate 601 and the lower plate 602. The tilt adjustment screw 1 603 and the tilt adjustment screw 2 604 are arranged in a diagonal structure. A plurality of cylindrical pins 606 are provided on the upper side of the upper plate 601 and the lower side of the lower plate 602, and a tension spring 605 is provided between the two cylindrical pins 606. The number of cylindrical pins 606 is 12, and the number of tension springs 605 is 6.

[0052] In this embodiment, the uniformity of the line spot beam can be adjusted, mainly by adjusting the deflection of the fifth lens in the x or y direction, and by placing a beam quality analyzer at the focus of the image plane to observe the energy distribution of the line spot to make the energy distribution uniform. The cylindrical line spot lens has a simple structure and can be integrated into the cutting head for use. It is also equipped with coaxial imaging to improve polishing accuracy.

[0053] like Figure 2 As shown, the object side and image side surfaces of the first lens 1 , the second lens 2 , the third lens 3 , the fourth lens 4 and the fifth lens 5 have curvature only in the X or Y direction.

[0054] like Figure 3 As shown, the laser generates a line spot on the focal plane after passing through the cylindrical line spot lens with a small focal depth and a long working distance. The shape of the cylindrical line spot lens with a small focal depth and a long working distance can be circular or square. In this case, the size of the incident light is 9 mm, and the focused spot in the Y direction is 0.009 mm, that is, the field lens can finally form a line spot of 9 mm × 0.009 mm on the working surface.

[0055] like Figure 5 As shown, the horizontal axis is the defocus distance, and the vertical axis is the FFT modulation transfer function data. In this case, the wavelength is 532nm. It can be seen from the figure that the MTF value is less than 0.15 in the defocus range of ±0.005mm, indicating that its depth of focus range is less than ±0.005mm.

[0056] It should be noted that the focal depth range of the cylindrical line spot lens with small focal depth and long working distance is less than ±0.005mm to achieve high-precision machining accuracy.

[0057] Because the working distance is greater than 15mm, in order to adapt to complex environments and high-precision laser processing of objects, the cylindrical line spot lens with small focal depth and long working distance has a working distance greater than 15mm and less than 20mm, thereby achieving the characteristics of a larger working distance, which can be installed with coaxial blowing and extremely small focal depth.

[0058] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A cylindrical line spot lens with a small focal depth and a long working distance, characterized in that: The invention comprises a cylindrical line spot lens body (500), wherein the cylindrical line spot lens body (500) comprises a first lens (1), a second lens (2), a third lens (3), a fourth lens (4) and a fifth lens (5), and the lenses have optical power, wherein the first lens (1), the second lens (2), the third lens (3), the fourth lens (4) and the fifth lens (5) are all arranged in a cylindrical lens structure, wherein two sides of the first lens (1) are respectively a first object side surface and a first image side surface, two sides of the second lens (2) are respectively a second object side surface and a second image side surface, two sides of the third lens (3) are respectively a third object side surface and a third image side surface, two sides of the fourth lens (4) are respectively a fourth object side surface and a fourth image side surface, and two sides of the fifth lens (5) are respectively a fifth object side surface and a fifth image side surface; The first object-side surface is a concave surface, and the first image-side surface is a convex surface; The second object-side surface is a concave surface, and the second image-side surface is a convex surface; The third object-side surface is a concave surface, and the third image-side surface is a convex surface; The fourth object-side surface is a convex surface, and the fourth image-side surface is a convex surface; The fifth object-side surface is a convex surface, and the fifth image-side surface is a concave surface; The curvature radius of the first object-side surface in the vertical direction is 8-17 mm, and the curvature radius of the first image-side surface in the vertical direction is 16-26 mm; The curvature radius of the second object-side surface in the vertical direction is 64-75 mm, and the curvature radius of the second image-side surface in the vertical direction is 18-27 mm; The curvature radius of the third object-side surface in the vertical direction is 9-18 mm, and the curvature radius of the third image-side surface in the vertical direction is 17-27 mm; The curvature radius of the fourth object-side surface in the vertical direction is 23-33 mm, and the curvature radius of the fourth image-side surface in the vertical direction is 65-80 mm; The curvature radius of the fifth object side surface in the vertical direction is 9-18 mm, and the curvature radius of the fifth image side surface in the vertical direction is 60-70 mm; The first lens (1), the second lens (2), the third lens (3), the fourth lens (4) and the fifth lens (5) are all made of BK7, K9 or fused quartz components; The center distance between the first lens (1) and the second lens (2) is 50-56 mm, the center distance between the second lens (2) and the third lens (3) is 3-5 mm, the center distance between the third lens (3) and the fourth lens (4) is 0.1-0.3 mm, and the center distance between the fourth lens (4) and the fifth lens (5) is 3-4 mm; The center thickness of the first lens (1) is 5-9 mm, the center thickness of the second lens (2) is 7-11 mm, the center thickness of the third lens (3) is 7-10 mm, the center thickness of the fourth lens (4) is 3-6 mm, and the center thickness of the fifth lens (5) is 5-8 mm.

2. The cylindrical line spot lens with a small focal depth and a long working distance according to claim 1, characterized in that: The curvature radius of the first object-side surface in the vertical direction is 12.9±0.01 mm, and the curvature radius of the first image-side surface in the vertical direction is 21.3±0.01 mm; The radius of curvature of the second object-side surface in the vertical direction is 69.9±0.01 mm, and the radius of curvature of the second image-side surface in the vertical direction is 22.7±0.01 mm; The curvature radius of the third object-side surface in the vertical direction is 13.1±0.01 mm, and the curvature radius of the third image-side surface in the vertical direction is 22.5±0.01 mm; The radius of curvature of the fourth object-side surface in the vertical direction is 28.3±0.01 mm, and the radius of curvature of the fourth image-side surface in the vertical direction is 71.9±0.01 mm; The curvature radius of the fifth object-side surface in the vertical direction is 13.7±0.01 mm, and the curvature radius of the fifth image-side surface in the vertical direction is 65.3±0.01 mm.

3. The cylindrical line spot lens with a small focal depth and a long working distance according to claim 1, characterized in that: The refractive indices of the first lens (1), the second lens (2), the third lens (3), the fourth lens (4) and the fifth lens (5) are all between 1.37 and 2.0, and the Abbe constants are all between 30 and 85.

4. The cylindrical line spot lens with a small focal depth and a long working distance according to claim 1, characterized in that: The outer diameter of the first lens (1) is 16-24 mm, the outer diameter of the second lens (2) is 20-26 mm, the outer diameter of the third lens (3) is 20-26 mm, the outer diameter of the fourth lens (4) is 20-26 mm, and the outer diameter of the fifth lens (5) is 20-26 mm.

5. The cylindrical line spot lens with a small focal depth and a long working distance according to claim 1, characterized in that: A reflective lens (400) is provided on the upper side of the cylindrical line spot lens body (500), the reflective lens (400) comprising a first reflective lens (401) and a second reflective lens (402), a collimating lens (100) and an infinite imaging lens (300) are provided on the upper side of the reflective lens (400), a CCD camera (200) is provided on the upper side of the infinite imaging lens (300), and an adjustable tilting platform (600) is provided on the lower side of the cylindrical line spot lens body (500).

6. The cylindrical line spot lens with a small focal depth and a long working distance according to claim 5, characterized in that: The adjustable tilting platform (600) includes an upper plate (601) and a lower plate (602), wherein the upper plate (601) and the lower plate (602) are arranged in a parallel and symmetrical structure. A tilt adjustment screw 1 (603) and a tilt adjustment screw 2 (604) are respectively arranged at the corner between the upper plate (601) and the lower plate (602), wherein the tilt adjustment screw 1 (603) and the tilt adjustment screw 2 (604) are arranged in a diagonal structure. A plurality of cylindrical pins (606) are arranged on the upper side of the upper plate (601) and the lower side of the lower plate (602), and a tension spring (605) is arranged between two of the cylindrical pins (606).

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