CN210498796U - Laser scanning device and laser scanning optical system - Google Patents

Abstract

The embodiment of the utility model provides a laser scanning device and laser scanning optical system. The laser scanning device comprises a laser generator, a first refraction mirror, a second refraction mirror, a third refraction mirror, a vibrating mirror and a driving device, wherein the laser generator is used for emitting a laser beam; the first refractor is close to one side of the laser generator for emitting the laser beam; the second refractive mirror and the third refractive mirror are positioned between the first refractive mirror and the galvanometer and are separated by a first preset distance; and the driving device is connected with the first refractive mirror and used for driving the first refractive mirror to reciprocate for a second preset distance along the light path direction of the laser beam. The embodiment of the utility model provides a can make focus on the laser spot size more to be close anticipated target in the working plane, reduced laser scanning device's error to a certain extent for the scanning result is more accurate.

Description

Laser scanning device and laser scanning optical system

Technical Field

The embodiment of the utility model provides a relate to laser focusing technical field, especially relate to a laser scanning device and laser scanning optical system.

Background

The laser scanning device can be widely applied to the fields of laser marking, laser engraving, laser processing and the like. In the related art, a laser scanning device capable of zooming generally relies on an imaging optical design in a sequential ray tracing mode, that is, incident laser light is approximated to parallel light by ignoring beam characteristics such as a beam divergence angle and intensity distribution of the incident laser light itself.

With regard to the above technical solutions, the inventors have found that at least some of the following technical problems exist: for example, the actual focused spot size of the laser scanning device may deviate from the expected design index, and the scanning result needs to be compensated and corrected by depending on experience during use, which is time-consuming and labor-consuming. Accordingly, there is a need to ameliorate one or more of the problems with the related art solutions described above.

It is noted that this section is intended to provide a background or context to the embodiments of the invention that are recited in the claims. The description herein is not admitted to be prior art by inclusion in this section.

SUMMERY OF THE UTILITY MODEL

An object of the embodiments of the present invention is to provide a laser scanning device and a laser scanning optical system, and then overcome one or more problems caused by the limitations and defects of the related art to a certain extent at least.

According to a first aspect of embodiments of the present invention, there is provided a laser scanning device, comprising a laser generator, a first refractive mirror, a second refractive mirror, a third refractive mirror, a galvanometer, and a driving device; wherein:

the laser generator is used for emitting a laser beam;

the first refractive mirror is close to one side of the laser generator for emitting the laser beam and is used for diverging the laser beam to form a divergent laser beam;

the second refractive mirror and the third refractive mirror are positioned between the first refractive mirror and the galvanometer and are separated by a first preset distance; the divergent laser beam is converged by the second refractive mirror and the third refractive mirror in sequence, then is irradiated to the surface of the lens of the galvanometer, and is reflected to the working surface by the surface of the lens of the galvanometer;

the driving device is connected with the first refractive mirror and used for driving the first refractive mirror to reciprocate a second preset distance along the light path direction of the laser beam; the first, second and third refractors have preset focal lengths respectively.

In an embodiment of the present invention, the first refractor is a negative lens, the second refractor and the third refractor are positive lenses.

In an embodiment of the present invention, the effective light passing diameter of the first refractor is larger than the spot diameter of the laser beam.

In an embodiment of the present invention, the second predetermined distance is less than 50 mm.

In an embodiment of the present invention, the predetermined focal length of the first refractor is between-25 mm and-5 mm.

In an embodiment of the present invention, the predetermined focal length of the second refractor is 100mm to 200 mm.

In an embodiment of the present invention, the predetermined focal length of the third refractor is 125mm to 225 mm.

In an embodiment of the present invention, the distance between the first refractive mirror and the second refractive mirror is 50mm to 150 mm; and/or the first preset distance between the second refractive mirror and the third refractive mirror is 0.1 mm-50 mm.

In an embodiment of the present invention, the distance between the third refractive mirror and the galvanometer is 5mm to 500 mm; and/or the distance between the galvanometer and the working surface is 10 mm-5000 mm.

According to a second aspect of embodiments of the present invention, there is provided a laser scanning optical system including the laser scanning device according to any one of the above embodiments.

The embodiment of the utility model provides a technical scheme can include following beneficial effect:

in the embodiment of the utility model, on one hand, the actual light beam characteristic of the laser emitted by the laser generator is considered, the laser beam is dispersed through the first refractor to form a divergent laser beam, and then the divergent laser beam is converged through the second refractor and the third refractor in sequence, and then is reflected to the working surface through the lens surface of the vibrating mirror; on the other hand, the driving device drives the first refractor to reciprocate along the light path direction of the laser beam, so that the zooming of the laser beam is realized, the size of a laser spot focused to a working plane is closer to an expected target, the error of the laser scanning device is reduced to a certain extent, and the scanning result is more accurate.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure. It is to be understood that the drawings in the following description are merely exemplary of the disclosure, and that other drawings may be derived from those drawings by one of ordinary skill in the art without the exercise of inventive faculty.

Fig. 1 shows a schematic structural diagram of a laser scanning device in an exemplary embodiment of the present invention;

fig. 2 shows a laser cross-sectional light intensity profile focused onto a work plane in an exemplary embodiment of the invention;

fig. 3 shows a laser spot profile focused onto a work plane in an exemplary embodiment of the invention.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

Furthermore, the drawings are merely schematic illustrations of embodiments of the invention, which are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus their repetitive description will be omitted. Some of the block diagrams shown in the figures are functional entities and do not necessarily correspond to physically or logically separate entities.

The laser machining process is a thermal variation process, the energy emitted by the laser is focused on a very small target area and transfers heat to the material to be machined, and the laser machining process is highly dependent on the energy absorbed by the material. The efficiency of the machining process is often a function of the square or cube of the irradiance. It can be concluded that the total energy and spatial distribution of the energy of the focused spot on the workpiece is critical to the success of the machining process, and that the workpiece is very sensitive to deformations in the shape of the spatial energy distribution of the laser beam. Therefore, the size of the focused light spot deviates from the expected design index, which inevitably brings large errors to the final process result. In the subsequent process, compensation and correction are carried out by adding a field lens and the like depending on experience, and time and labor are wasted.

First, in the present exemplary embodiment, a laser scanning apparatus is provided. Referring to fig. 1, the laser scanning apparatus may include a laser generator 100, a first refractive mirror 200, a second refractive mirror 300, a third refractive mirror 400, a galvanometer 500, and a driving device 600. The laser generator 100 is used for emitting a laser beam, and the first refractor 200 is disposed near a side of the laser generator 100 emitting the laser beam and is used for diverging the laser beam to form a divergent laser beam. The second refractor 300 and the third refractor 400 are located between the first refractor 200 and the galvanometer 500, and are spaced by a first preset distance, wherein the divergent laser beams sequentially pass through the second refractor 300 and the third refractor 400 to be converged and then irradiate the surface of the lens of the galvanometer 500, and are reflected to the working surface 700 by the surface of the lens of the galvanometer 500. The driving device 600 is connected to the first refractive mirror 200, and is configured to drive the first refractive mirror 200 to move back and forth along the optical path direction of the laser beam by a second preset distance. In addition, the first, second, and third refractors 200, 300, and 400 have preset focal lengths, respectively.

According to the laser scanning device, on one hand, the actual light beam characteristics of the laser emitted by the laser generator, such as spot size, emission angle and the like, are considered, the laser beam is dispersed through the first refractor to form a divergent laser beam, then the divergent laser beam is converged through the second refractor and the third refractor in sequence, and then the divergent laser beam is reflected to the working surface through the lens surface of the vibrating mirror; on the other hand, the driving device drives the first refractor to reciprocate along the light path direction of the laser beam, so that the zooming of the laser beam is realized, the size of a laser spot focused to a working plane is closer to an expected target, the error of the laser scanning device is reduced to a certain extent, and the scanning result is more accurate.

Next, each part of the above-described laser scanning apparatus in the present exemplary embodiment will be described in more detail with reference to fig. 1 to 3.

In one embodiment, as shown in FIG. 1, the laser generator 100 may include, but is not limited to, a solid state laser, a fiber laser, and a semiconductor laser. The driving device 600 may be a direct-drive motor connected to a lead screw and then connected to the first refractive mirror 200, and the lead screw drives the first refractive mirror 200 to reciprocate along the optical path direction of the laser beam while the motor operates, thereby achieving zooming. The galvanometer 500 may be scanned in a single direction, i.e., in the X direction or the Y direction, or may be scanned in two directions, i.e., in the X direction and the Y direction. For example, in one specific example, galvanometer 500 scans in both the X and Y directions, wherein the rotation angle of the galvanometer is calculated from the target operating position and operating distance.

In one embodiment, the first refractive mirror 200 is a negative lens and the second and third refractive mirrors 300 and 400 are positive lenses. The negative lens is a thick-center and thick-periphery lens having the ability to diverge light, while the positive lens is a thick-center and thin-periphery lens having the ability to converge light. In addition, because the negative lens is used for diverging the laser beam to form the divergent laser beam, and two positive lenses are used for converging and diverging the laser beam, therefore, the diameter of first refractor 200 compared with second refractor 300 and third refractor 400 can be less, and the quality is lighter, and drive arrangement has higher speed and precision when driving first refractor 200 to move. The accuracy of the whole laser scanning device is further improved.

In a specific example, the mirror surface shapes of the first refractor 200, the second refractor 300 and the third refractor 400 can be spherical surfaces or aspherical surfaces, and the manufacturing material can be a light-transmitting material such as glass, plastic, quartz, and the like. The actual diameters of the first, second, and third refractors 200, 300, and 400 are not less than the effective clear diameter.

In one embodiment, the effective light-passing diameter of the first refractive mirror 200 is larger than the spot diameter of the laser beam to ensure that the laser beam generated by the laser generator 100 can entirely pass through the first refractive mirror 200. The effective light transmission diameters of the second refractor 300 and the third refractor 400 can be calculated by using the principle of conservation of etendue, according to the spot diameter of the laser beam emitted from the laser generator 100, the divergence angle of the divergent laser beam, and the focused spot size of the desired target.

In an embodiment, the second preset distance is smaller than 50mm, calculated based on the optical zoom curve. That is, the first refractor 200 is reciprocally moved within the distance near the laser generator 100 side, so that the zooming of the laser beam can be better achieved, the size of the laser spot focused into the working plane is further made to approach the desired target, the error of the laser scanning apparatus is reduced, and the scanning result is more accurate.

In one embodiment, the preset focal length of the first refractive mirror 200 is between-25 mm and-5 mm, the preset focal length of the second refractive mirror 300 is between 100mm and 200mm, and the preset focal length of the third refractive mirror 400 is between 125mm and 225mm, so that the laser beam finally reflected by the lens surface of the galvanometer 500 onto the working surface 700 has more suitable energy for scanning.

Based on the above-described embodiments, in one example, the distance between the first and second refractive mirrors 200 and 300 is 50mm to 150mm, and the distance between the third refractive mirror 400 and the galvanometer 500 is 5mm to 500 mm. In yet another example, the first preset distance between the second and third refractors 300 and 300 is 0.1mm to 50mm, and the interval between the galvanometer 500 and the working surface 700 is 10mm to 5000 mm. Through the above parameter settings of the distance between the first refractor 200 and the second refractor 300, the distance between the third refractor 400 and the vibrating mirror 500, the distance between the second refractor 300 and the third refractor 300, and the distance between the vibrating mirror 500 and the working surface 700, the laser spot size and/or energy can be better adjusted, and experiments show that the laser spot size focused into the working plane can be further close to an expected target, the error of the laser scanning device is reduced, and the accuracy of the laser scanning device is improved.

Selecting a specific embodiment, and performing simulation verification by adopting a Monte Carlo ray tracing method:

in this example, the laser generator 100 is a solid laser generator, and emits laser light with a spot diameter of 2mm and a beam divergence half-angle of 0.3 mrad. The first refractor 200 is a negative lens, the focal length is-9.5 mm, the effective light passing diameter is 2mm, and the material is fused quartz. The second refractor 300 is a positive lens, the focal length is 160mm, the effective light passing diameter is 20mm, and the material is fused quartz. The third refractive mirror 400 is a positive lens with a focal length of 190mm, an effective light transmission diameter of 21mm, and is made of fused quartz. The distance between the first refractor 200 and the second refractor 300 is 80mm, the distance between the second refractor 300 and the third refractor 400 is 2mm, the distance between the third refractor 400 and the vibrating mirror 500 is 50mm, and the distance between the vibrating mirror 500 and the target working surface 700 is 1000 mm. The front-back position change range of the first refractor 200 driven by the direct drive motor 600 is-1 mm, and the back intercept length change range of the corresponding focusing optical system is 950 mm-1230 mm.

The target focused spot diameter is about 0.063mm, calculated according to the principle of conservation of etendue.

And (3) carrying out simulation verification by using a light source model for actually emitting laser beams and adopting a Monte Carlo ray tracing method. The laser section light intensity distribution is gaussian distribution, the laser power is normalized to 1W, and the simulated laser section light intensity distribution is shown in fig. 2. The simulated laser spot distribution in the target working plane is shown in fig. 3, the diameter of the laser spot is about 0.06mm, which is close to the theoretical calculated value of 0.063mm, and the design requirement is met.

A laser scanning optical system is further provided in this example embodiment, including the laser scanning apparatus according to any one of the foregoing embodiments, and the specific implementation is similar to the foregoing embodiments and is not described herein again.

It is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," and the like in the foregoing description are used for indicating or indicating the orientation or positional relationship relative to that shown in the drawings, merely for the purpose of describing embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be considered limiting of embodiments of the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are 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 one or more of that feature. In the description of the embodiments of the present invention, "a plurality" means two or more unless specifically limited otherwise.

In the embodiments of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly, e.g., as fixed or detachable connections or as an integral part; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In embodiments of the invention, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact between the first and second features, or may comprise contact between the first and second features through another feature not in direct contact. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by those skilled in the art.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims (10)

1. A laser scanning device is characterized by comprising a laser generator, a first refraction mirror, a second refraction mirror, a third refraction mirror, a vibrating mirror and a driving device; wherein:

the laser generator is used for emitting a laser beam;

the first refractive mirror is close to one side of the laser generator for emitting the laser beam and is used for diverging the laser beam to form a divergent laser beam;

the second refractive mirror and the third refractive mirror are positioned between the first refractive mirror and the galvanometer and are separated by a first preset distance; the divergent laser beam is converged by the second refractive mirror and the third refractive mirror in sequence, then is irradiated to the surface of the lens of the galvanometer, and is reflected to the working surface by the surface of the lens of the galvanometer;

the driving device is connected with the first refractive mirror and used for driving the first refractive mirror to reciprocate a second preset distance along the light path direction of the laser beam; the first, second and third refractors have preset focal lengths respectively.

2. The laser scanning device according to claim 1, wherein the first refractive mirror is a negative lens, and the second refractive mirror and the third refractive mirror are positive lenses.

3. The laser scanning device according to claim 2, wherein an effective light-passing diameter of the first refractive mirror is larger than a spot diameter of the laser beam.

4. The laser scanning device according to claim 3, wherein the second predetermined distance is less than 50 mm.

5. The laser scanning device according to claim 4, wherein the preset focal length of the first refractor is-25 mm to-5 mm.

6. The laser scanning device according to claim 5, wherein the preset focal length of the second refractor is 100mm to 200 mm.

7. The laser scanning device according to claim 6, wherein the predetermined focal length of the third refractor is 125mm to 225 mm.

8. The laser scanning device according to any one of claims 1 to 7, wherein a distance between the first refractive mirror and the second refractive mirror is 50mm to 150 mm; and/or the first preset distance between the second refractive mirror and the third refractive mirror is 0.1 mm-50 mm.

9. The laser scanning device according to claim 8, wherein the third refractive mirror and the galvanometer are spaced apart by 5mm to 500 mm; and/or the distance between the galvanometer and the working surface is 10 mm-5000 mm.

10. A laser scanning optical system comprising the laser scanning device according to any one of claims 1 to 9.

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