A telecentric laser field mirror lens and laser scanning system thereof

Abstract

The present invention discloses a telecentric laser field mirror lens and a laser scanning system thereof, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged along the laser propagation direction, wherein the first lens is a double concave spherical negative lens, the second lens is a concave-convex spherical negative lens, the third lens is a concave-convex spherical positive lens, the fourth lens is a plano-convex spherical positive lens, the fifth lens is a double convex spherical positive lens, and the sixth lens is a double-plane lens, which can achieve a better flat field effect, so that laser processing can be carried out stably and efficiently.

Description

Technical Field

[0001] The invention relates to the field of optical equipment, and in particular to a telecentric laser field mirror lens and a laser scanning system thereof. Background Art

[0002] In the process of modern industrial manufacturing, laser processing is widely used in various processing technologies such as welding, surface treatment, drilling, and marking because of its advantages such as high precision and high efficiency. Laser processing mainly consists of four parts, namely laser, power supply, optical system and mechanical system. The optical system generally includes X / Y galvanometer and scanning field mirror. The scanning field mirror is generally installed at the end of the laser system to form a focusing plane. By controlling the reflection angle of the X / Y galvanometer, the laser beam is focused on different areas of the focusing plane, thereby realizing marking, welding, laser cleaning, 3D printing and other processes. The scanning field mirror is generally divided into: flat field mirror and telecentric field mirror. However, the telecentric scanning field mirrors in the industry often have the disadvantage of poor flat field effect, which affects the stable and efficient operation of laser processing. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a telecentric laser field lens, which can achieve a good flat field effect, so that laser processing can be carried out stably and efficiently.

[0004] The present invention also proposes a laser scanning system having the telecentric laser field mirror lens.

[0005] According to the telecentric laser field mirror lens of the embodiment of the first aspect of the present invention, it includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in sequence along the laser propagation direction, the first lens is a double concave spherical negative lens, the second lens is a concave-convex spherical negative lens, the third lens is a concave-convex spherical positive lens, the fourth lens is a plano-convex spherical positive lens, the fifth lens is a double convex spherical positive lens, and the sixth lens is a double-plane lens.

[0006] The telecentric laser field mirror lens according to the embodiment of the present invention has at least the following beneficial effects: the laser emits a beam of laser with a fixed spot, which enters the telecentric laser field mirror lens after being reflected by the X / Y galvanometer mirror, so that the laser passes through the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens in sequence, and after multiple refractions of the lenses, the exit pupil of the lens is infinitely far in the image space, so that the main light of the focused light beam is perpendicular to the focal plane under any field of view angle, so that the telecentric laser field mirror lens has a better flat field effect, so that laser processing can be carried out stably and efficiently.

[0007] According to some embodiments of the present invention, a main lens barrel is further included, and the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all disposed in the main lens barrel.

[0008] According to some embodiments of the present invention, a locking ring is further included, and the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all fixed in the main lens barrel through the locking ring.

[0009] According to some embodiments of the present invention, a spacer is provided between the first lens and the second lens, between the second lens and the third lens, between the third lens and the fourth lens, between the fourth lens and the fifth lens, and between the fifth lens and the sixth lens.

[0010] According to some embodiments of the present invention, a rubber ring with a buffering function is disposed on a side of the sixth lens opposite to the spacer.

[0011] According to some embodiments of the present invention, the first lens includes a first spherical surface and a second spherical surface, the radius of curvature of the first spherical surface is -110.16±0.11016 mm, and the radius of curvature of the second spherical surface is -234.29±0.23429 mm; the second lens includes a third spherical surface and a fourth spherical surface, the radius of curvature of the third spherical surface is -40.0±0.04 mm, and the radius of curvature of the fourth spherical surface is 66.12±0.06612 mm; the third lens includes a fifth spherical surface and a sixth spherical surface, the radius of curvature of the fifth spherical surface is -40.0±0.04 mm, and the radius of curvature of the fourth spherical surface is 66.12±0.06612 mm. The curvature radius of the sixth spherical surface is -247.7±0.2477 mm, and the curvature radius of the sixth spherical surface is 85.18±0.08518 mm; the fourth lens includes a first plane and a seventh spherical surface, and the curvature radius of the seventh spherical surface is 134.75±0.13475 mm; the fifth lens includes an eighth spherical surface and a ninth spherical surface, the curvature radius of the eighth spherical surface is 206.4±0.2064 mm, and the curvature radius of the ninth spherical surface is 438.76±0.43876 mm; the sixth lens includes a second plane and a third plane.

[0012] According to some embodiments of the present invention, the center thickness of the first lens is 6.0±0.1 mm; the center thickness of the second lens is 16.0±0.1 mm; the center thickness of the third lens is 15.0±0.1 mm; the center thickness of the fourth lens is 16.0±0.1 mm; the center thickness of the fifth lens is 17.0±0.1 mm; and the center thickness of the sixth lens is 5.0±0.1 mm.

[0013] According to some embodiments of the present invention, the air spacing between the first lens and the second lens on the optical axis is 16.0 mm; the air spacing between the second lens and the third lens on the optical axis is 1.3 mm; the air spacing between the third lens and the fourth lens on the optical axis is 1.3 mm; the air spacing between the fourth lens and the fifth lens on the optical axis is 1.3 mm; and the air spacing between the fifth lens and the sixth lens on the optical axis is 12.0 mm.

[0014] According to some embodiments of the present invention, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all made of quartz glass, the refractive index of the quartz glass is 1.45, and the dispersion coefficient of the quartz glass is 67.7.

[0015] The laser scanning system according to the second embodiment of the present invention comprises the telecentric laser field mirror lens according to the first embodiment of the present invention.

[0016] The laser scanning system according to the embodiment of the present invention has at least the following beneficial effects: the laser emits a beam of laser with a fixed spot, which enters the telecentric laser field mirror lens after being reflected by the X / Y galvanometer mirror, so that the laser passes through the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens in sequence, and after multiple refractions of the lenses, the exit pupil of the lens is infinitely far away in the image space, so that the main light of the focused light beam is perpendicular to the focal plane under any field of view angle, so that the telecentric laser field mirror lens has a better flat field effect, so that laser processing can be carried out stably and efficiently.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0019] Figure 1 A schematic diagram of the internal structure of a telecentric laser field mirror lens according to an embodiment of the present invention;

[0020] Figure 2 This is a 14mm entrance pupil optical path diagram of an embodiment of the present invention;

[0021] Figure 3 This is a 20mm entrance pupil optical path diagram of an embodiment of the present invention;

[0022] Figure 4 This is an MTF curve diagram of an entrance pupil of 14 mm according to an embodiment of the present invention;

[0023] Figure 5 This is an MTF curve diagram of an entrance pupil of 20 mm according to an embodiment of the present invention;

[0024] Figure 6 It is a Through Focus MTF curve diagram of an entrance pupil of 14mm in an embodiment of the present invention;

[0025] Figure 7 It is a Through Focus MTF curve diagram of an entrance pupil of 20mm in an embodiment of the present invention;

[0026] Figure 8 This is the optical dispersion pattern of an entrance pupil of 14 mm according to an embodiment of the present invention;

[0027] Fig. 9 This is the optical dispersion pattern of an entrance pupil of 20 mm according to an embodiment of the present invention;

[0028] Fig.10 The field curvature and distortion diagram of the embodiment of the present invention with an entrance pupil of 14 mm;

[0029] Fig.11 The field curvature and distortion diagram of the embodiment of the present invention with an entrance pupil of 20 mm;

[0030] Fig.12 4 is a relative illumination diagram of an embodiment of the present invention.

[0031] Reference numerals:

[0032] A first lens 100 , a second lens 200 , a third lens 300 , a fourth lens 400 , a fifth lens 500 , a sixth lens 600 , a main lens barrel 700 , a locking ring 800 , a spacer 900 , and a rubber ring 1000 . DETAILED DESCRIPTION

[0033] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0034] In the description of the present invention, it should be understood that descriptions involving orientation, such as orientation or positional relationship indicated as up, down, etc., are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0035] In the description of the present invention, unless otherwise clearly defined, words such as setting and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0036] Reference Figure 1 The telecentric laser field mirror lens of the first embodiment of the present invention comprises a first lens 100, a second lens 200, a third lens 300, a fourth lens 400, a fifth lens 500 and a sixth lens 600 arranged in sequence along the laser propagation direction, the first lens 100 is a double concave spherical negative lens, the second lens 200 is a concave-convex spherical negative lens, the third lens 300 is a concave-convex spherical positive lens, the fourth lens 400 is a plano-convex spherical positive lens, the fifth lens 500 is a double convex spherical positive lens, and the sixth lens 600 is a double-plane lens. The laser emits a beam of laser with a fixed spot, which is reflected by the X / Y galvanometer and enters the telecentric laser field lens. The laser passes through the first lens 100, the second lens 200, the third lens 300, the fourth lens 400, the fifth lens 500 and the sixth lens 600 in sequence. After multiple refractions of the lenses, the exit pupil of the lens is infinitely far in the image space, so that the main light of the focused light beam is perpendicular to the focal plane under any field of view angle, so that the telecentric laser field lens has a good flat field effect, so that the laser processing can be carried out stably and efficiently.

[0037] Reference Figure 1 In some specific embodiments of the present invention, a main lens barrel 700 is further included, and the first lens 100, the second lens 200, the third lens 300, the fourth lens 400, the fifth lens 500 and the sixth lens 600 are all arranged in the main lens barrel 700. The first lens 100, the second lens 200, the third lens 300, the fourth lens 400, the fifth lens 500 and the sixth lens 600 are all arranged in the main lens barrel 700, and are arranged in sequence according to the direction of laser propagation, so that after the laser passes through the main lens barrel 700, the laser can be perpendicular to the focal plane, produce a good flat field effect, and can make the image quality uniform within the scanning field range and reach the diffraction limit.

[0038] Reference Figure 1 In some specific embodiments of the present invention, a locking ring 800 is further included, and the first lens 100, the second lens 200, the third lens 300, the fourth lens 400, the fifth lens 500 and the sixth lens 600 are all fixed in the main lens barrel 700 through the locking ring 800. Through the locking ring 800, the first lens 100, the second lens 200, the third lens 300, the fourth lens 400, the fifth lens 500 and the sixth lens 600 are stably installed and fixed in the main lens barrel 700.

[0039] In some specific embodiments of the present invention, a spacer 900 is disposed between the first lens 100 and the second lens 200, between the second lens 200 and the third lens 300, between the third lens 300 and the fourth lens 400, between the fourth lens 400 and the fifth lens 500, and between the fifth lens 500 and the sixth lens 600. The spacer 900 can effectively prevent adjacent lenses from being squeezed against each other and causing wear.

[0040] In some specific embodiments of the present invention, a rubber ring 1000 with a buffering effect is provided on one side of the sixth lens 600 relative to the spacer 900. The rubber ring 1000 has a good buffering effect, reduces the deformation of the sixth lens 600, and can also play a good sealing role, and plays a good protective role for the inside of the main lens barrel 700.

[0041] In some specific embodiments of the present invention, the first lens 100 includes a first spherical surface and a second spherical surface, the curvature radius of the first spherical surface is -110.16±0.11016 mm, and the curvature radius of the second spherical surface is -234.29±0.23429 mm; the second lens 200 includes a third spherical surface and a fourth spherical surface, the curvature radius of the third spherical surface is -40.0±0.04 mm, and the curvature radius of the fourth spherical surface is 66.12±0.06612 mm; the third lens 300 includes a fifth spherical surface and a sixth spherical surface, and the curvature radius of the fifth spherical surface is -40.0±0.04 mm, and the curvature radius of the fourth spherical surface is 66.12±0.06612 mm. The curvature radius of the sixth spherical surface is -247.7±0.2477 mm, and the curvature radius of the sixth spherical surface is 85.18±0.08518 mm; the fourth lens 400 includes a first plane and a seventh spherical surface, and the curvature radius of the seventh spherical surface is 134.75±0.13475 mm; the fifth lens 500 includes an eighth spherical surface and a ninth spherical surface, and the curvature radius of the eighth spherical surface is 206.4±0.2064 mm, and the curvature radius of the ninth spherical surface is 438.76±0.43876 mm; the sixth lens 600 includes a second plane and a third plane. Among them, a positive value represents a convex spherical surface, and a negative value represents a concave spherical surface; the spherical surfaces or planes of the first lens 100, the second lens 200, the third lens 300, the fourth lens 400, the fifth lens 500 and the sixth lens 600 are set so that the lens group arranged in the main lens barrel 700 has a good flat field effect.

[0042] In some specific embodiments of the present invention, the center thickness of the first lens 100 is 6.0±0.1 mm; the center thickness of the second lens 200 is 16.0±0.1 mm; the center thickness of the third lens 300 is 15.0±0.1 mm; the center thickness of the fourth lens 400 is 16.0±0.1 mm; the center thickness of the fifth lens 500 is 17.0±0.1 mm; the center thickness of the sixth lens 600 is 5.0±0.1 mm. The center thickness of the first lens 100, the second lens 200, the third lens 300, the fourth lens 400, the fifth lens 500 and the sixth lens 600 is set so that the telecentric laser field lens has a good normal effect.

[0043] In some specific embodiments of the present invention, the air spacing between the first lens 100 and the second lens 200 on the optical axis is 16.0 mm; the air spacing between the second lens 200 and the third lens 300 on the optical axis is 1.3 mm; the air spacing between the third lens 300 and the fourth lens 400 on the optical axis is 1.3 mm; the air spacing between the fourth lens 400 and the fifth lens 500 on the optical axis is 1.3 mm; the air spacing between the fifth lens 500 and the sixth lens 600 on the optical axis is 12.0 mm, so that the telecentric laser field lens has a good normal effect.

[0044] In some specific embodiments of the present invention, the first lens 100, the second lens 200, the third lens 300, the fourth lens 400, the fifth lens 500 and the sixth lens 600 are all made of quartz glass, the refractive index of quartz glass is 1.45, and the dispersion coefficient of quartz glass is 67.7. Quartz glass has high transmittance, low linear expansion coefficient and good uniformity, so that the telecentric laser field lens has strong anti-laser damage ability, high transmittance and good imaging quality.

[0045] Reference Figures 2 to 12 , the following specific embodiments are provided to supplement the technical effects that can be achieved by the above embodiments of the present invention.

[0046] In this embodiment, the working distance of the laser field mirror lens is 220 mm, the incident light pupil can have two types, namely 14 mm and 20 mm, and the working band is: 1064 nm.

[0047] Reference Figures 2 to 5 , respectively, are the optical path images corresponding to two different incident pupils. By comparing the two images, we can see Figure 2 The spot on the left has a smaller aperture of 14mm; Figure 3 The spot diameter is 20mm. In addition, there are some differences in the distance from the spot to the first lens of the lens, which are 42mm and 50mm respectively. The 20mm spot is slightly longer.

[0048] Reference Figure 6 and Figure 7 , which are MTF curves corresponding to two different light spots. In general, in optical design, MTF curves are usually used to evaluate the resolution characteristics of the designed lens. Comparing the two figures, we can see that the imaging resolution of the two different light spots is good, and the curves of all fields of view almost overlap and are very close to the diffraction limit.

[0049] Reference Figure 8 and Fig. 9 The dot plots of two different spot imaging are shown in the figure. DBJ represents the object field of view, IMA represents the image field of view. Airy Radius represents the radius of the Airy disk, and RMS Radius represents the mean square error radius of the diffuse spot, both in micrometers. Figure 8 It can be seen that the Airy Radius of the 14mm spot is 15.51μm, the center RMS Radius is 1.399μm, and the edge RMS Radius is 3.009. According to optical theory, if the RMS Radius is smaller than the Airy Radius, it means that the energy concentration and aberration correction of the on-axis and off-axis points are very good, achieving the ideal resolution. Although the RMSRadius shown in the dot map of the 20mm spot is slightly larger, it is also smaller than the Airy Radius, so it also has a very good resolution.

[0050] Reference Fig.10 and Fig.11 As shown in the field curvature and distortion diagram, the field curvature is only 0.2mm and the distortion is less than 2%. The small field curvature of the lens indicates that the degree of focusing deviation is very small, that is, the flat field effect is very good, which is very beneficial for use in laser applications, and the distortion is also within a reasonable range.

[0051] Reference Fig.12 The relative illumination curve shown shows that the energy intensity of the lens image field is very high, which is very suitable for laser applications.

[0052] In summary, the telecentric laser field mirror lens designed in the embodiment of the present invention has the characteristics of good flat field effect, high resolution, and extremely small aberration.

[0053] The laser scanning system according to the second embodiment of the present invention comprises the telecentric laser field mirror lens according to the first embodiment of the present invention.

[0054] According to the laser scanning system of the embodiment of the present invention, the laser emits a beam of laser with a fixed spot, which enters the telecentric laser field lens after being reflected by the X / Y galvanometer mirror, so that the laser passes through the first lens 100, the second lens 200, the third lens 300, the fourth lens 400, the fifth lens 500 and the sixth lens 600 in sequence. After multiple refractions of the lenses, the exit pupil of the lens is infinitely far in the image space, so that the main light of the focused light beam is perpendicular to the focal plane under any field of view angle, so that the telecentric laser field lens has a good flat field effect, so that the laser processing can be carried out stably and efficiently.

[0055] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0056] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A telecentric laser field lens, characterized in that: The invention comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged along the propagation direction of the laser, wherein the first lens is a double concave spherical negative lens, the second lens is a concave-convex spherical negative lens, the third lens is a concave-convex spherical positive lens, the fourth lens is a plano-convex spherical positive lens, the fifth lens is a double convex spherical positive lens, and the sixth lens is a double plane lens; wherein the components with optical refractive power in the telecentric laser field lens are only the first lens, the second lens, the third lens, the fourth lens and the fifth lens, and the object side surface of the second lens is a concave surface , the image side surface of the second lens is convex, the object side surface of the third lens is concave, the image side surface of the third lens is convex, the object side surface of the fourth lens is flat, and the image side surface of the fourth lens is convex; the center thickness of the first lens is 6.0±0.1 mm; the center thickness of the second lens is 16.0±0.1 mm; the center thickness of the third lens is 15.0±0.1 mm; the center thickness of the fourth lens is 16.0±0.1 mm; the center thickness of the fifth lens is 17.0±0.1 mm; the center thickness of the sixth lens is 5.0±0.1 mm.

2. The telecentric laser field lens according to claim 1, characterized in that: It also includes a main lens barrel, in which the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all arranged.

3. The telecentric laser field lens according to claim 2, characterized in that: It also includes a locking ring, and the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all fixed in the main lens barrel through the locking ring.

4. The telecentric laser field lens according to claim 3, characterized in that: Spacers are provided between the first lens and the second lens, between the second lens and the third lens, between the third lens and the fourth lens, between the fourth lens and the fifth lens, and between the fifth lens and the sixth lens.

5. The telecentric laser field lens according to claim 4, characterized in that: A rubber ring with a buffering function is arranged on one side of the sixth lens opposite to the spacer.

6. The telecentric laser field lens according to claim 1, characterized in that: The air distance between the first lens and the second lens on the optical axis is 16.0 mm; the air distance between the second lens and the third lens on the optical axis is 1.3 mm; the air distance between the third lens and the fourth lens on the optical axis is 1.3 mm; the air distance between the fourth lens and the fifth lens on the optical axis is 1.3 mm; the air distance between the fifth lens and the sixth lens on the optical axis is 12.0 mm.

7. The telecentric laser field lens according to claim 1, characterized in that: The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all made of quartz glass, the refractive index of the quartz glass is 1.45, and the dispersion coefficient of the quartz glass is 67.

7.

8. A laser scanning system, characterized in that: It comprises the telecentric laser field mirror lens as described in any one of claims 1 to 7.

Images