KR20210141063A - A laser processing apparatus using infinite focus optical system - Google Patents

Abstract

In accordance with an embodiment of the present invention, a laser processing device using an infinite focus optical system comprises: a laser generation unit for outputting a first laser beam; a pre-optical system for condensing the first laser beam to an infinite focus optical system; the infinite focus optical system for reflecting or transmitting the focused first laser beam to a processing target; and a control unit for controlling the laser generation unit, the pre-optical system and/or the infinite focus optical system. The infinite focus optical system includes: an optics having a symmetrical shape having a predetermined curvature and reflecting or transmitting the focused first laser beam to the processing target as a second laser beam having a focal length greater than or equal to a predetermined distance; and a moving unit which rotates and/or moves the optics so that the focused first laser beam is not emitted to the same area of the infinite focus optics. In accordance with the present invention, the degree of freedom of laser processing is very high.

Description

A laser processing apparatus using infinite focus optical system

The present specification proposes a laser processing apparatus using an infinity focus or a pseudo infinity focus optical system.

A laser processing apparatus that provides various processing such as welding, cutting, and drilling for various materials in an industrial field has been provided.

The laser processing apparatus uses high thermal energy while minimizing damage to the material, thereby maintaining the processing quality at a precise and high level. In particular, a laser output device that generates a high output of several tens of kW has been recently provided with a focus on IR laser and fiber oscillation methods.

Such high-power laser output devices are particularly in demand in the shipbuilding field, which requires long-term processing over a large area, and in the steel field, which requires a long process distance due to harsh environments such as high temperature, steam, and dust.

However, when such a high-power laser output device is applied to an optical system having a finite focal length as in the prior art, various problems exist as follows.

For example, when cutting thick metal (eg, cutting a thick plate), a conventional optical system has a focal length in which energy density is concentrated in a focal area and low energy density is formed in a non-focus area due to a finite focal length. A star energy density imbalance occurs. For this reason, in the case of a conventional laser processing apparatus using a finite focus optical system, there is a problem in that the metal cannot be cut uniformly, and the metal is cut non-uniformly, such as a tapered shape.

In addition, in the case of processing an object to be processed having a non-uniform surface, conventionally, since the focus of the laser beam must be controlled to move along the surface of the object to be processed, there is a problem in that control complexity and difficulty are greatly increased. Even in the case of processing an object to be processed with a complex structure/shape, the same problem has existed in the prior art.

Therefore, in the present specification, not only can all of the above-described problems be solved, but also a laser processing apparatus with high processing efficiency is proposed.

According to an embodiment of the present invention, for outputting a first laser beam, a laser generator; a pre-optical system for condensing the first laser beam to an infinite focus optical system; The infinity-focus optical system for reflecting or transmitting the focused first laser beam to a processing target; and a controller for controlling the laser generator, the pre-optical system, and/or the infinity-focusing optical system. Including, wherein the infinite focus optical system has a symmetrical shape having a predetermined curvature, and reflects or transmits the focused first laser beam to the processing target as a second laser beam having a focal length greater than or equal to a preset distance, optics ; and a moving unit which rotates and/or moves the optics so that the focused first laser beam is not irradiated to the same area of the infinite focus optics. may include.

According to an embodiment of the present invention, since the output of the infinitely focused laser beam is possible, the user can freely process the desired shape regardless of the shape, size, thickness, surface condition, etc. of the object to be processed, so the degree of freedom of laser processing has a very high effect.

In addition, according to an embodiment of the present invention, it has the effect that large-area and high-speed processing is possible.

Effects of the present invention are not limited thereto, and various other effects will be described in more detail below with reference to each drawing below.

1 is a view illustrating an optical lens used in a conventional laser processing apparatus.
2 is a view showing embodiments of a laser processing apparatus for cutting a processing object having a thick thickness.
3 is a view showing embodiments of a laser processing apparatus for processing a processing object having a non-uniform surface.
4 is a diagram illustrating embodiments of a laser processing apparatus for processing a processing target having a complex structure.
5 is a block diagram of a laser processing apparatus to which a (similar) infinity focus optical system is applied according to an embodiment of the present invention.
6 is a configuration diagram of a laser processing apparatus to which a (similar) infinity-focus optical system is applied according to an embodiment of the present invention.
7 is a diagram illustrating an infinity-focus optical system implemented using infinity-focus optics according to an embodiment of the present invention.
8 is a diagram illustrating a pseudo infinity focus optic according to a first embodiment of the present invention.
Fig. 9 (a) is a cross-sectional view of a pseudo infinity focus optic according to a second embodiment of the present invention, and Fig. 9 (b) is a three-dimensional view of the pseudo infinity focus optic according to a second embodiment of the present invention. .
10 is a diagram illustrating examples of optics applicable to a (pseudo) infinite focus optical system according to an embodiment of the present invention.
11 is an image of a cross-section of a laser beam output from a laser processing apparatus according to an embodiment of the present invention.
12 is a diagram illustrating a rotating infinite focus optics according to an embodiment of the present invention.
13 is a diagram illustrating an irradiation pattern of a laser beam formed on a pseudo-infinite focus optic according to rotation/movement of the pseudo-infinite focus optic according to an embodiment of the present invention.

Since the technology to be described below may have various changes and may have various embodiments, specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the technology described below to specific embodiments, and it should be understood to include all changes, equivalents, or substitutes included in the spirit and scope of the technology described below.

Terms such as first, second, A, and B may be used to describe various components, but the components are not limited by the above terms, and only for the purpose of distinguishing one component from other components. used only as For example, a first component may be named as a second component, and similarly, a second component may also be referred to as a first component without departing from the scope of the technology to be described below. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

In terms of the terms used herein, the singular expression should be understood to include a plural expression unless the context clearly dictates otherwise, and terms such as "comprises" refer to the described feature, number, step, operation, and element. , parts or combinations thereof are to be understood, but not to exclude the possibility of the presence or addition of one or more other features or numbers, step operation components, parts or combinations thereof.

Prior to a detailed description of the drawings, it is intended to clarify that the classification of the constituent parts in the present specification is merely a division according to the main function that each constituent unit is responsible for. That is, two or more components to be described below may be combined into one component, or one component may be divided into two or more for each more subdivided function. In addition, each of the constituent units to be described below may additionally perform some or all of the functions of other constituent units in addition to the main function it is responsible for. Of course, it may be carried out by being dedicated to it.

In addition, in performing the method or the method of operation, each process constituting the method may occur differently from the specified order unless a specific order is clearly described in context. That is, each process may occur in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.

1 is a view illustrating an optical lens used in a conventional laser processing apparatus.

In order to use the laser beam 101 for processing, more than a critical level of integrated energy is required. To this end, an optical lens for condensing the laser beam 101 is required. Conventionally, as shown in FIG. 1, an optical lens (for example, a convex lens or a Fresnel lens) 100 having a finite focal length. was used As shown in FIG. 1 , the laser beam 101 passing through the optical lens 100 shows a light distribution pattern that is focused on the focus f of the optical lens 100 and then spreads out. That is, the energy density of the laser beam 101 passing through the optical lens 100 is concentrated on the focus f, and shows a distribution that decreases as the distance from the focus f is increased.

The laser beam 101 passing through the optical lens 100 is seen as a straight beam (or parallel beam) with the naked eye, but actually has a hyperbolic shape 101-1 having the thinnest thickness at the focal point. That is, the laser beam 101 passing through the optical lens 100 having a finite focus has an unbalanced energy density distribution in the hyperbola form 101-1 in which the energy density is concentrated at the focal point f.

When processing is performed with the laser beam 101 having such an unbalanced energy density distribution, various processing problems occur, which will be described in detail with reference to each drawing below.

2 to 4 are views showing processing examples of a finite focus optical system and an infinite focus optical system.

First, Figure 2 is a view showing embodiments of the laser processing apparatus for cutting the processing object 21 having a thick thickness. In particular, Figure 2 (a) is an embodiment in which the laser processing device to which the finite focus optical system is applied cuts the processing target 21, Figure 2 (b) is the laser processing device to which the infinity focus optical system is applied cuts the processing target 21 It corresponds to an embodiment that

Cutting metals thicker than 100mm in shipbuilding and steelmaking is a very difficult task. In particular, heavy plate cutting that requires isolation from contaminants such as concrete sorting and dismantling of nuclear power plants cannot be done by mechanical methods, and cutting using a laser beam is essential. Recently, as a high-power laser of 20 kW or more can be applied, research on a direct cutting method/device using a laser beam is being actively conducted. However, in the case of a conventional laser processing apparatus using a finite focus optical system, the following problems exist due to an unbalanced energy density distribution.

Referring to FIG. 2( a ), in the case of a laser processing apparatus to which a finite focus optical system is applied, as described above, since the output laser beam 101 has an unbalanced energy density distribution in a hyperbola form, only in the focal region f Substantial cutting is possible, and there is a problem that the non-focus region 20 is not cut because the energy density is not high. As a result, when the laser beam 101 is irradiated without moving the focus f, there is a problem that the processing object 21 is cut in an unbalanced shape such as a tapered shape. To solve this, cutting while moving the focal point f in the cutting direction, or increasing the width (ie, beam waist, depth of focus) of the laser beam 101 in the focal region f to several mm to cut with a low light concentration can be applied, but a large number of molten regions causes loss of plate material, requires very large pulling energy, and various problems such as complicated machining process have occurred.

On the other hand, as shown in FIG. 2(b), in the case of a laser processing apparatus to which an infinite-focus optical system or a similar infinite-focus optical system is applied, the focus of the optical lens does not exist or a very long distance (eg, several to several hundred m) ) and a parallel beam (or straight beam) 102 having a (substantially) balanced energy density distribution is output, so the above-mentioned problems do not occur.

In the present specification, an infinity-focus optical system means an optical system including infinite-focus optics having an infinite focal length (ie, no focus), and a pseudo-infinite focal length optical system has a finite focal length, but a predetermined distance (eg, For example, it refers to an optical system that includes pseudo-infinite focus optics of several to hundreds of meters) or more. Such an infinite-focus optical system and a similar infinite-focus optical system are optical systems having a focal length greater than or equal to a predetermined distance, and may be collectively referred to as an 'infinite-focus optical system'.

3 is a diagram illustrating embodiments of a laser processing apparatus for processing a processing object having a non-uniform surface 31 - 2 (eg, surface laser cleaning processing). In particular, Figure 3 (a) is an embodiment in which the laser processing apparatus to which the finite focus optical system is applied processes the surface 31-2 of the processing object, Figure 3 (b) is the laser processing apparatus to which the infinity focus optical system is applied of the processing object It corresponds to an embodiment in which the surface 31 - 2 is processed.

Referring to FIG. 3( a ), in the case of a laser processing apparatus to which a finite focus optical system is applied, as described above, the output laser beam 101 has an unbalanced energy density distribution in the form of a hyperbola, so that the focus is on the surface of the object to be processed. In order for (f) to be continuously positioned, the finite focus optical system must move up and down (31-1) along the surface curvature (31-2) of the object to be processed. To this end, the laser processing apparatus must recognize the surface curvature 31-2 of the object to be processed with a sensor, and separate the configuration for vertically moving the finite focus optical system 31-1 along the recognized surface curvature 31-2. Therefore, there was a problem that the manufacturing cost of the laser processing apparatus increases, and the control complexity and difficulty increase. In particular, when the amount of light and the temperature of the object to be processed are high, since the sensing accuracy of the surface curvature 31 - 2 is lowered, there is a problem that processing complexity and difficulty are further increased.

On the other hand, as shown in FIG. 2(b), in the case of a laser processing apparatus to which an infinity-focus optical system or a pseudo-infinite-focus optical system is applied, a straight beam (or parallel beam) 102 having a (substantially) balanced energy density distribution. ) is output, there is no need to move the optical system/focus along the curvature 31-2 of the surface, so that the above-mentioned problems do not occur. In particular, in the case of laser cleaning processing, since most processing objects do not have a planar structure (that is, the surface is non-uniform), the utility of the (quasi) infinite focus optical system becomes very large. In addition, in the case of large-area cleaning processing in the shipbuilding field, it was very difficult to apply to the actual field because the laser processing device had to be enlarged to move the pseudo infinity-focused optical system along the surface of the ship. A large-area cleaning process is possible only with a small-angle beam scan.

4 is a view illustrating embodiments of a laser processing apparatus for processing a processing target 41 having a complex structure (eg, dismantling a building, dismantling a nuclear power plant, sorting processing inside a complex structure, etc.). In particular, Fig. 4 (a) is an embodiment in which the laser processing apparatus to which the finite focus optical system is applied processes the processing target 41 of a complex structure, Fig. 4 (b) is the processing of the complex structure of the laser processing apparatus to which the infinity focus optical system is applied It corresponds to an embodiment in which the object 41 is processed.

The dismantling of nuclear power plants has recently emerged as a new issue, and the dismantling of nuclear power plants is being performed using laser processing equipment due to problems such as the complexity of the internal structure and radioactive contamination. However, in the case of a laser processing apparatus to which a finite focus optical system is applied, as shown in FIG. There is a problem of high. On the other hand, as shown in FIG. 4(b), in the case of a laser processing apparatus to which an infinity-focus optical system or a pseudo-infinite-focus optical system is applied, a straight beam (or parallel beam) 102 having a (substantially) balanced energy density distribution. ) is output, there is no need to move the optical system/focus in a complicated manner along the pipe 41 surface (that is, the shape/structure of the object to be processed) (simple movement in the preset/fixed direction 43). do not occur In particular, in the case of a (quasi) infinite focus optical system, since processing is possible in various directions and from a long distance, it has the effect that processing is possible even with a complicated structure or a dangerous object.

(Pseudo) Infinite focus optical system, in addition to the above-mentioned advantages/effects, can output a laser beam with a constant energy density without being constrained by position and distance. It can be very usefully applied to processing, etc.

Such (pseudo) infinite focus optical system may be configured/designed with infinite focus optics as a central axis, and (pseudo) infinite focus optics are symmetrical mirrors and reflective mirrors (eg, SiC, metal, etc.) having a predetermined curvature. Alternatively, it may be implemented as an optical lens. A specific embodiment of the (similar) infinity focus optics will be described in detail below with reference to FIGS. 7 to 9, and a laser processing apparatus to which the (similar) infinity focus optical system is applied will be first looked at.

5 is a block diagram of a laser processing apparatus to which a (similar) infinite focus optical system is applied according to an embodiment of the present invention, and FIG. 6 is a laser processing apparatus to which a (similar) infinite focus optical system is applied according to an embodiment of the present invention It is a configuration diagram.

5 and 6, the laser processing apparatus 500 according to an embodiment of the present invention, a laser generating unit 501, a pre-optical system 502, (similar) infinite focus optical system 503 and / or control unit (504).

The laser generating unit 501 may generate a continuous wave or pulsed wave laser beam 103 . In particular, the laser generating unit 501 according to an embodiment of the present invention may generate a high-power laser beam 103 . have. For example, the laser generator 501 may generate the laser beam 103 in the range of several W to 100 kW.

The laser beam 103 output from the laser generator 501 is a carbon dioxide laser, a fiber laser, a disk laser, a diode laser, and a diode pumped solid state laser (DPSSL, Diode Pumped Solid State Laser). Systems), an ultra short pulse laser, and an eximer laser. In particular, in the case of the laser processing apparatus 500 to which the (similar) infinite focus optical system 503 is applied as in the present invention, the laser beam 103 output from the laser generator 501 has a wavelength range and fiber beam delivery. There is no limit on whether In other words, the (pseudo) infinite focus optical system 503 applies the same construction principle as that of the laser generator, so that the material and coating of the optics can be freely changed according to / according to the wavelength of the laser of the laser generator, so the laser of all wavelengths It can be applied regardless of whether or not a fiber beam is transmitted to the beam.

The laser generator 501 may be any one of a green laser, a blue laser, and a UV laser, but the embodiment of the present invention is not limited thereto. That is, the laser generating unit 501 may be any one of various laser generating devices widely known in the art to which the present invention pertains, generating a high-power laser beam 103 of several tens of Kw.

The pre-optical system 502 performs a function of condensing the laser beam 101 so that the laser processing apparatus can output a laser beam greater than or equal to a threshold, and for this purpose, it may include at least one or more focusing optics 502-1. As the condensing optics 502-1, for example, a convex lens and/or a Fresnel lens may be used, but is not limited thereto, and various lenses or mirrors capable of performing the function of condensing 101 may be used. In particular, the pre-optical system 502 may serve to focus 101 the laser beam 103 output from the laser generator 501 to the infinite focus optical system 503 using the condensing optics 502-1. have.

(Similar) The infinite focus optical system 503 may perform a function of reflecting or transmitting 102 the laser beam 101 condensed and irradiated by the pre-optical system 502 to the processing target 21 . At this time, the focal length of the laser beam 102 reflected or transmitted from the (similar) infinity-focusing optical system 503 is infinite (ie, a non-focused parallel beam) or finite, but more than a predetermined distance (eg, several m to distances of several hundred meters) (ie long focus). However, unlike the long focus case of a general optical system, the diameter of the beam irradiated to the surface of the optical system and the beam diameter at the position where the focus is formed do not differ significantly. Accordingly, the laser beam 102 reflected or transmitted from the (pseudo) infinite focus optical system 503 and irradiated to the processing object 21 is a parallel beam with (substantially) parallel boundaries or a (pseudo) straight beam having a constant thickness. may correspond to

To this end, the (pseudo) infinite focus optical system 503 may include optics 503 - 1 having a symmetrical shape having a predetermined curvature. As the optics 503 - 1 , infinity-focus optics having an infinite focal length or pseudo-infinite-focus optics having a finite focal length but longer than a preset distance may be used. A more detailed description of an embodiment of the optics 503 - 1 will be described below with reference to FIGS. 7 to 9 .

When the focused laser beam 102 is continuously irradiated to the same area of the optics 503-1 in the (pseudo) infinite focus optical system 503, high-density energy is concentrated in the area, resulting in permanent thermal damage. problems may arise. This, in turn, leads to incurring additional costs for replacing the (pseudo) infinite focus optics 503-1. Accordingly, the (similar) infinite focus optical system 503 of the present invention may include a moving part (not shown) for preventing the laser beam 102 from being continuously irradiated to one area.

The moving unit rotates and/or moves the optics 503-1 (high speed) to prevent partial thermal damage that may occur as the focused laser beam 102 is irradiated to the same area of the optics 503-1. function can be performed. To this end, the moving unit may include at least one hardware component (eg, a motor, a circuit, etc.), and (high-speed) rotation and / or can be moved.

In addition, the (similar) infinite focus optical system 503 further includes a water cooling unit (not shown) for cooling the heat of the optics 503 - 1 in order to prevent permanent thermal damage to the optics 503 - 1 described above. may include

Due to the provision of the above-described components, in the (quasi) infinite focus optical system 503 of the present invention, partial thermal damage does not occur, so that the replacement cycle of the optics 503-1 is guaranteed to be long.

The control unit 504 may communicate with at least one component unit included in the laser processing apparatus 500 to implement the embodiments proposed in the present specification, and may control them. Accordingly, the laser processing apparatus 500 may be described as being identical to the control unit 504 . The control unit 504 is a central processing unit (CPU), a micro processor unit (MPU), a micro controller unit (MCU), an application processor (AP), an application processor (AP), or any form well known in the art. It may be configured to include at least one processor.

Meanwhile, although not shown in this figure, the laser processing apparatus 500 may further include an input unit (not shown) for receiving user settings. The input unit may include at least one hardware component for receiving various user settings, and may transmit the received user settings to the control unit. In particular, the input unit receives laser beam setting information such as shape, size, height, diameter, radius, width, and/or width information of the laser beam, and processing setting information such as processing method/form of the processing target and/or processing target. You can get input from the user.

7 is a diagram illustrating an infinite-focus optical system implemented using infinite-focus optics according to an embodiment of the present invention.

When the laser beam is incident on the infinite focus optical system, the laser beam is focused at the focal point f of the infinite focus optics 503 - 1 . Conversely, when the laser beam 101 is incident on the infinite focus optics 503-1 while passing through the focal point f, the focal length is infinite (or has no focal point) like the parallel beam (or straight beam) 102 . ) is propagated/reflected/transmitted by a laser beam. Based on this principle, the pre-optical system, as shown in this figure, passes through the focus f of the infinity-focused optics 503-1 and enters the infinity-focused optics 503-1 through the laser beam 101. can be investigated. To this end, the pre-optical system may be tilted at a preset angle so that the focused laser beam 101 passes through the focus and then enters the infinite focus optics 503 - 1 to be provided in the laser processing apparatus. Alternatively, a moving unit for adjusting the angle and distance of the pre-optical system may be separately provided in the laser processing apparatus, and the controller controls the moving unit so that the focused laser beam 101 passes through the focus point f and the infinite focus optics 503- 1) Incident angle and distance can be adjusted so that it is incident on. In summary, in the laser processing apparatus, a preset angle and distance may be set between the pre-optical system and the infinity-focused optics 503-1 (or the infinity-focused optical system).

In the case of the infinite focus optical system according to the present embodiment, since the position/point at which the laser beam is incident on the optical surface of the infinite focus optics is not located on the optical axis 71, it corresponds to the 'Off axis' method. If the position at which the laser beams 101 and 102 are incident on the optical surface of the infinite focus optics is located on the optical axis 71 of the optical system, it corresponds to the 'On axis' method. This on-axis method corresponds to the embodiment of the pseudo-infinite focus optical system of FIG. 9, which will be described later.

The infinity focus optics 503 - 1 may be implemented as aspherical optics having predetermined curvature and axial symmetry, and having minimized aberration effects. For example, as the aspherical optics, a parabolic shape, an elliptical shape, a hyperbolic shape, or a free form surface optical lens/mirror in which several similar curved surfaces are combined may be used.

The moving unit may rotate (or move) the infinite-focus optics 503-1 at high speed by using the axis of symmetry of the shape of the infinite-focus optics 503-1 as a rotation axis under the control of the controller. This is to prevent thermal damage that may occur as the laser beam 101 is intensively irradiated to one area, as described above.

When the infinite focus optical system according to this embodiment is applied, the parallel beam (or straight beam) can reach a very long distance, so it is located at a very long distance (for example, a distance of several m to several hundred m). It has the advantage that the processing object can also be processed efficiently.

Hereinafter, a pseudo-infinite focus optical system will be described. In the case of pseudo-infinite focus optics, parallel beams (or straight beams) do not reach as long distances as in infinity optics, but at much longer distances (e.g., several m to several tens of m) (i.e., long distances) than in conventional finite focus optics. It has the effect of reaching the focal point). However, the long focus formed by the pseudo-infinite-focus optical system proposed in the present specification has a distinct difference from the long-focus (about several meters) formed by the general finite-focus optical system. For example, if it is assumed that a multimode 10kW beam is irradiated to a general finite focus optical system, a large incident beam (tens of mm) must be used due to thermal problems, and even if the focus is formed at a distance of several m, it is less than 1mm. The condensed beam cannot be obtained. In particular, in the case of a general finite-focus optical system, the M^2 value representing the high-power multimode beam mode is large in the range of 10 to 80, and the focal size is small even if the incident beam is assumed to be 20 mm and the focal length is 5 m, and factors such as aberration are not taken into account. It is about 7mm, so it is difficult to use in practice. On the other hand, in the case of the pseudo-infinite focus optical system of the present invention, there is no significant difference between the size of the incident beam and the size of the beam at the focal point, and there is a clear difference in that the incident beam can be made smaller than 1 mm.

8 is a diagram illustrating a pseudo infinity focus optic according to a first embodiment of the present invention.

The same principle as the case of the infinite focus optical system illustrated in FIG. 7 is applied to the pseudo-infinite focus optical system according to the first embodiment, except that other optics are used. Accordingly, the description of FIG. 7 may be applied in the same/similar manner to the present embodiment. In the case of the pseudo-infinite-focus optical system according to the first embodiment, the laser beam 101 passes through the focal point f of the pseudo-infinite-focus optics 503-2 and enters the pseudo-infinite-focus optics 503-2. A structure to investigate is disclosed. That is, in the case of the first embodiment, the pseudo-infinite focus optics are used differently from the embodiment of FIG. 7 , and unlike the infinity-focus optics, the pseudo-infinite focus optics can also be applied to the optical surface 503-2 where a certain aberration may occur. It is possible to increase the degree of freedom in device configuration.

Even in the case of the pseudo-infinite-focus optical system according to the present embodiment, the positions of the laser beams 101 and 102 irradiated to the optical surface of the pseudo-infinite-focus optics (that is, the laser beams 101 and 102 and the optical surface of the pseudo-infinite-focus optics) Since the location where they meet) is not located on the optical axis 71 of the optical system, it corresponds to the 'Off axis' method.

The pseudo-infinite focus optics 503 - 2 may be implemented as optics having a shape having a predetermined curvature and axial symmetry. In particular, the pseudo-infinite focus optics 503 - 2 according to the present embodiment may be implemented as spherical optics in which the axis of symmetry can be freely set. For example, as the spherical optics, a freeform surface lens/mirror in which a hemispherical shape or several curved surfaces equivalent thereto are combined may be used. In the case of such spherical optics, as long as the axis of rotation or reciprocating motion passes through the center of the sphere, free rotation or reciprocating motion can be set. Therefore, in the case of this embodiment, the axis for rotation or reciprocating movement can be selected very freely and conveniently, and depending on the embodiment, several rotation shafts can be used in combination, so that the degree of freedom of the device configuration is very high.

The moving unit rotates or moves the pseudo-infinite-focus optics 503-2 at high speed using the axis of symmetry (or preset motion/rotation axis) of the shape of the pseudo-infinite focus optics 503-2 as the rotation/movement axis under the control of the controller. can This is to prevent thermal damage that may occur as the laser beam 101 is intensively irradiated to one area, as described above.

In the case of the pseudo-infinite focus optics 503 - 2 , since the degree of freedom of setting the symmetry axis/rotation axis is high due to the symmetrical structure, it is possible to add translational motion in a direction perpendicular to the rotational axis during the rotational motion. That is, the range of the area to which the laser beam is irradiated is wider than in the case of infinite focus optics, so that thermal stability can be improved, and the replacement cycle due to thermal damage is longer. As such free rotation or movement is possible, a certain movement path can be set so that the laser beam 101 can be uniformly incident on all surfaces of the pseudo-infinite focus optics 503-2. and 13 will be described below.

Fig. 9 (a) is a cross-sectional view of a pseudo infinity focus optic according to a second embodiment of the present invention, and Fig. 9 (b) is a three-dimensional view of the pseudo infinity focus optic according to a second embodiment of the present invention. .

In the laser processing apparatus to which the pseudo-infinite-focus optical system is applied according to the second embodiment, the pseudo-infinite-focus optical system may be provided in a state inclined at a preset angle (ie, the optical system or optical axis is inclined at a preset angle). This is to apply the 'On axis' method in which the laser beams 101 and 102 entering the pseudo-infinite focus optical system are positioned on the optical axis 71 of the pseudo-infinite focus optics 503-3. The focus optics 503 - 3 may be provided in the laser processing apparatus in a state inclined at a predetermined angle.

In the case of the ‘On axis’ method, if the rotation axis is set as the optical axis of the optical system, the position where the laser beam hits does not change even if the optical system rotates, causing thermal damage to the corresponding position. Therefore, in the case of the present optical system to which the on axis method is applied, it is necessary to set the rotation/movement axis differently from the optical system to which the off axis method is applied.

Referring to FIG. 9A , in the case of the pseudo-infinite focus optics according to the second embodiment, the focused and incident laser beam 101 is at a constant angle with respect to the optical axis 71 of the pseudo-infinite-focus optics 503-3. , but the location where it meets the optical surface of the pseudo-infinite focus optics can be exactly on the optical axis (ie, 'On axis' method). This ‘on axis’ method is more advantageous for angle selection and adjustment than the ‘off axis’ case because the laser beam is incident on the optical axis of the optical system. The distance fd1 from the formation position of the focal point f' of the laser beam 101 to the point where the pseudo-infinite focus optics optical surface 503-3 and the laser beam 101 meet is the focal point f of the pseudo-infinite focus optics. It may be set to be approximately/substantially equal to the distance. On the other hand, in the case of the off-axis method, the two focal lengths should be exactly the same, but since the incident laser beam 101 is not on the optical axis, a difference in the range of several % is acceptable. It is also possible to finely adjust the spreading angle of the laser beam 102 that is reflected or transmitted from and output.

As pseudo-infinite focus optics that can be applied to the second embodiment, a lens/mirror having a Troid-shaped optical surface with different curvatures in the x-direction (horizontal/horizontal direction) and the y-direction (vertical/vertical direction) may be used. can be, as illustrated in FIG. 9(b). The optical surface in the X direction should be a curved surface having rotational symmetry, and a representative spherical surface may be easily applied. In this case, the rotation/movement axis 81 of the pseudo-infinite focus optics may be set as the central axis of curvature of the curved surface in the x direction. The optical surface in the Y direction may be selected from various curved surfaces without considering symmetry. For example, a parabolic, elliptical, hyperbolic, spherical, or free surface equivalent thereto or a combination thereof may be selected. can be

The moving unit may rotate or move the pseudo-infinite-focus optics 503-3 at high speed using the axis of symmetry of the shape of the pseudo-infinite-focus optics 503-3 as a rotation axis under the control of the controller. This is to prevent thermal damage that may occur as the laser beam 101 is intensively irradiated to one area, as described above.

10 is a diagram illustrating embodiments of optics applicable to a (pseudo) infinite focus optical system according to an embodiment of the present invention.

In particular, FIG. 10(a) is a parabolic-shaped optic, FIG. 10(b) is an optic with a through hole formed in the center in the parabolic shape of FIG. 10(a), and FIG. An example is optics in which a predetermined curvature is formed. The laser beam condensed from the pre-optical system may be reflected or transmitted after being incident on the optics and then propagated to the object to be processed.

In addition, various shapes of optics having a symmetric shape of a predetermined curvature may be applied/used as optics of a (pseudo) infinite focus optical system, and are not limited to the shape of the above-described embodiment. According to the type and position of the installed optics, the relative position/angle of the installed pre-optical system with respect to the (pseudo) infinite focus optical system may be determined. For example, when the optical system provided in the laser processing apparatus is an infinity-focused optical system and an infinity-focused optic having a parabolic shape is provided, the pre-optical system causes the laser beam to pass through the focus of the infinity-focused optics and enter the infinity-focused optics. It may be provided on the laser processing apparatus at a possible position and angle.

11 is an image as a result of simulating a cross-section of a laser beam output from a laser processing apparatus according to an embodiment of the present invention.

In particular, this figure is an image that simulates a laser beam cross-section in a position 5 m away from the optical system as a reference point, -2 m to 2 m from the reference point, and a total distance of 4 m (ie, 3 m to 7 m distance from the optical system). (a) shows the output laser beam of the laser processing apparatus to which the infinite focus optical system is applied, and FIG.

Referring to FIG. 11( a ), it can be seen that the shape, size, and uniform energy density distribution in the cross-section of the laser beam remain the same regardless of the distance.

Referring to FIG. 11(b), although not as much as FIG. 11(a), it can be confirmed that the shape, size, and uniform energy density distribution in the cross-section of the laser beam are all maintained almost uniformly regardless of the distance.

12 is a diagram illustrating a rotating infinite focus optics according to an embodiment of the present invention.

As described above, in order to prevent thermal damage due to continuous laser beam irradiation, the (similar) infinite focus optics 503 - 1 may be rotated or moved by a moving unit provided together. In the case of this figure, the infinite focus optics 503 - 1 is a diagram illustrating an embodiment in which the infinity focus optics 503 - 1 rotate clockwise with the axis of symmetry c as the rotation axis by the moving part. In this case, the laser beam incident on the infinity optics 503 - 1 is actually fixed in the laser device, but as shown in this figure, as the infinity optics rotate/moves, as the infinity focus optics rotate/move, the laser beam is infinity focus on the infinity focus optics. It appears to be irradiated with the pattern/shape 101-1 rotating in a counterclockwise direction, which is opposite to the rotation direction of the optics.

13 is a diagram illustrating an irradiation pattern of a laser beam formed on a pseudo-infinite focus optic according to rotation/movement of the pseudo-infinite focus optic according to an embodiment of the present invention.

As described above, in the case of the pseudo-infinite focus optics 503 - 2 according to the first embodiment, it is possible to freely set the axis of symmetry due to the symmetrical shape. This means that various/free rotation/movement movements of the pseudo-infinite focus optics are possible.

Accordingly, in order to prevent thermal damage due to laser beam irradiation, the controller controls the laser beam 131 to be uniformly irradiated to the entire surface of the pseudo-infinite focus optics 503 - 2 . Paths 132-1 and 132-2 to move on the optics 503-2 are preset, and the laser beam 131 moves to the pseudo-infinite focus optics 503 according to the set movement paths 132-1 and 132-2. -2) The moving part can be controlled so that it can move on the top. 13(a) and 13(b) are diagrams illustrating embodiments of the movement paths 132-1 and 132-2. In particular, FIG. 13B is a diagram illustrating an embodiment in which the pseudo infinite focus optics is divided into two regions based on the center line 133 and the movement path 132-2 for each region is set separately. In addition, the movement path may be freely set in various patterns/shapes/paths, and is not limited to the embodiment of the present drawing. In particular, the controller may set a path so that the laser beam 131 can evenly sweep the entire surface (or an area greater than or equal to a preset ratio) of the pseudo-infinite focus optics 503-2 during one cycle (or a preset time). have.

In particular, when setting the movement paths 132-1 and 132-2, the controller according to an embodiment of the present invention may consider the characteristics of the laser beam 131 incident to the pseudo-infinite focus optics 503-2. . To this end, as described above, the laser processing apparatus may further include an input unit for receiving a setting related to the laser beam 131 from the user. The user may input various laser beam settings such as shape, size, height, diameter, radius, width, and/or width information of the laser beam 131 to be used for processing through the input unit. The control unit irradiates the laser beam 131 based on the setting of the laser beam 131 , and moves the laser beam 131 to evenly irradiate the entire surface of the pseudo-infinite focus optics 503 - 2 . The paths 132-1 and 132-2 may be set more specifically and efficiently.

For example, the controller divides the total area of the pseudo-infinite focus optics 503 - 2 to which the laser beam 131 is incident by the cross-sectional area of the laser beam 131 , so that the specific number of times the laser beam 131 reciprocates, the horizontal /You can set the movement path by calculating the vertical movement distance. Accordingly, the path/distance moving on the pseudo-infinite focus optics 503 - 2 may be different according to the characteristics of the laser beam 131 . As a fragmentary example, the controller sets the movement path of the laser beam 131 based on the movement path 132-1 as shown in FIG. 13(a) for the circular pseudo-infinite focus optics 503-2. In this case, the horizontal/vertical movement path/distance of the first laser beam having a cross-sectional diameter of 1 mm may be set longer than that of the second laser beam having a cross-sectional diameter of 2 mm. At this time, if the time until the laser beam 131 completes the preset movement path is previously specified (ie, when the period is preset to a specific time), the movement must be completed during the same period, so that the first The moving speed of the laser beam becomes faster than the moving speed of the second laser beam.

In general, when a laser beam with output P watts (W) is incident on an optical system with an area of radius r for time t seconds (s), the energy density (ie, average incoming energy incident per unit area) on the optical system surface (ED1) can be derived through Equation 1.

In the case of a conventional finite-focus optical system applied to an actual high-power laser device, a 5kW output laser is incident on a fixed finite-focus optical system in which a circular beam with a diameter of 10 mm (radius r = 5 mm) is incident on the fixed finite-focus optical system, in this case for 1 second per unit time. The incoming energy density is about 64 W/mm^2 according to Equation 1. That is, this level of energy density can be seen as a value that has been verified to be applied to existing devices.

When the (similar) infinite focus optical system of the present invention is applied, the energy density (ED2) received by the optical system through rotation/movement of the optical system may be derived through Equation (2).

where v is the rotational/moving linear speed of the optical surface at the position where the laser beam is hit/irradiated/incident.

In the case of forming an infinity focus with a diameter of 0.5mm, that is, a radius of r=0.25mm, which is sufficient for laser processing, even if the optical system moves/rotates only at a speed of about 350 mm/s, the energy density received by the optical system surface is about 57 W/mm^ 2, which is lower than the energy density of the conventional finite focus optical system (ED1 = about 64W/mm^2). That is, in the case of the (similar) infinite focus optical system of the present invention, it can be seen that the durability against thermal damage is very high compared to the conventional one. If the feed speed of the (pseudo) infinity-focusing optical system is made faster, it is possible to apply a smaller diameter beam, and even if the output energy of the laser beam used is low, a smaller diameter beam can be used.

Embodiments according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of implementation by hardware, an embodiment of the present invention provides one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), FPGAs ( field programmable gate arrays), a processor, a controller, a microcontroller, a microprocessor, and the like.

In addition, in the case of implementation by firmware or software, an embodiment of the present invention is implemented in the form of a module, procedure, function, etc. that performs the functions or operations described above, and is stored in a recording medium readable through various computer means. can be recorded. Here, the recording medium may include a program command, a data file, a data structure, etc. alone or in combination. The program instructions recorded on the recording medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software. For example, the recording medium includes a magnetic medium such as a hard disk, a floppy disk, and a magnetic tape, an optical recording medium such as a compact disk read only memory (CD-ROM), a digital video disk (DVD), and a floppy disk. magneto-optical media, such as a disk, and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions may include high-level language codes that can be executed by a computer using an interpreter or the like as well as machine language codes such as those generated by a compiler. Such hardware devices may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

In addition, the device or terminal according to the present invention may be driven by a command that causes one or more processors to perform the functions and processes described above. For example, such instructions may include interpreted instructions, such as script instructions, such as JavaScript or ECMAScript instructions, or executable code or other instructions stored on a computer-readable medium. Furthermore, the device according to the present invention may be implemented in a distributed manner over a network, such as a server farm, or may be implemented in a single computer device.

Furthermore, a computer program (also known as a program, software, software application, script or code) mounted on the device according to the invention and executing the method according to the invention includes compiled or interpreted language or a priori or procedural language. It can be written in any form of programming language, and can be deployed in any form, including stand-alone programs, modules, components, subroutines, or other units suitable for use in a computer environment. A computer program does not necessarily correspond to a file in a file system. A program may be in a single file provided to the requested program, or in multiple interacting files (eg, files that store one or more modules, subprograms, or portions of code), or portions of files that hold other programs or data. (eg, one or more scripts stored within a markup language document). The computer program may be deployed to be executed on a single computer or multiple computers located at one site or distributed over a plurality of sites and interconnected by a communication network.

Although each drawing has been described separately for convenience of description, it is also possible to design to implement a new embodiment by merging the embodiments described in each drawing. In addition, the present invention is not limited to the configuration and method of the embodiments described as described above, but the above-described embodiments are configured by selectively combining all or part of each embodiment so that various modifications can be made. could be

In addition, although preferred embodiments have been illustrated and described above, the present specification is not limited to the specific embodiments described above, and those of ordinary skill in the art to which the specification pertains without departing from the gist of the claims Various modifications are possible by the person, of course, these modifications should not be individually understood from the technical spirit or perspective of the present specification.

500: laser processing device
501: laser generating unit
502: pre-optics
503: infinite focus optical system
504: control
21: processing target

Claims (19)

a laser generator for outputting a first laser beam;
a pre-optical system for condensing the first laser beam to an infinite focus optical system;
The infinite focus optical system for reflecting or transmitting the focused first laser beam to a processing target; and
a control unit for controlling the laser generator, the pre-optical system, and/or the infinity-focusing optical system; including,
The infinity focus optical system,
an optic that has a symmetrical shape having a predetermined curvature and reflects or transmits the focused first laser beam to the processing target as a second laser beam having a focal length greater than or equal to a predetermined distance; and
a moving unit which rotates and/or moves the optics so that the focused first laser beam is not irradiated to the same area of the infinity-focused optics; Including, laser processing apparatus. The method of claim 1,
The focused first laser beam is irradiated to the focus of the optics and is reflected or transmitted to the processing target, laser processing apparatus. 3. The method of claim 2,
The optics are
Corresponding to infinite focus optics in which the focal length is infinite, laser processing apparatus. 4. The method of claim 3,
The infinity focus optics is a parabolic shape, an elliptical shape, a hyperbolic shape, an aspherical shape, or a free-form mirror or lens made of a combination of at least two of the shapes. 4. The method of claim 3,
The moving unit,
While the focused first laser beam is irradiated to the infinity focus optics, the infinity focus optics rotates the axis of symmetry of the infinity focus optics shape as a rotation axis. 3. The method of claim 2,
The optics correspond to pseudo-infinite focus optics in which the focal length is finite, but greater than or equal to the preset distance, laser processing apparatus. 7. The method of claim 6,
The pseudo-infinite focus optics,
The pseudo-infinite focus optics is a hemispherical spherical mirror or lens, a laser processing apparatus. 7. The method of claim 6,
The moving unit,
While the focused first laser beam is irradiated to the pseudo-infinite focus optics, the pseudo-infinite focus optics rotates the axis of symmetry of the pseudo-infinite focus optics shape to a rotation axis, and/or moves in a direction perpendicular to the symmetry axis Let the laser processing equipment. 9. The method of claim 8,
The control unit is
and controlling the moving part so that the focused first laser beam is irradiated along a preset movement path on the pseudo-infinite focus optics for one cycle. 10. The method of claim 9,
The preset movement path is,
The first focused laser beam is set to a path that can be irradiated to an area equal to or greater than a predetermined ratio of the pseudo-infinite focus optics during the one cycle. 11. The method of claim 10,
an input unit for receiving a setting related to the first laser beam from a user; Further comprising a, laser processing apparatus. 12. The method of claim 11,
The control unit is
Receives a setting related to the first laser beam from the input unit, and sets the preset path based on the received setting, a laser processing apparatus. 13. The method of claim 12,
The setting for the first laser beam is,
Containing the shape, size, height, diameter, radius, width, and / or width information of the first laser beam, laser processing apparatus. The method of claim 1,
The focused first laser beam is irradiated to a point where the optical surface of the optics and the optical axis of the optics meet and is reflected or transmitted to the processing target. 15. The method of claim 14,
The optics correspond to pseudo-infinite focus optics in which the focal length is finite, but greater than or equal to the preset distance, laser processing apparatus. 16. The method of claim 15,
The pseudo-infinite focus optics,
A mirror or lens having an optical surface in the shape of a toroid having different curvatures in the horizontal and vertical directions, a laser processing apparatus. 17. The method of claim 16,
The pseudo-infinite focus optics,
A spherical shape in the horizontal direction,
In the vertical direction, a parabolic shape, an elliptical shape, a hyperbolic shape, an aspherical shape, or a mirror or a lens of a freeform shape made of a combination of at least two of the shapes. 17. The method of claim 16,
The moving unit,
and rotating the pseudo-infinite focus optics about a preset rotation axis while the focused first laser beam is irradiated to the pseudo-infinite focus optics. 19. The method of claim 18,
The preset rotation axis is
The laser processing apparatus, which is set as the central axis of curvature of the curved surface formed in the horizontal direction among the optical surfaces of the pseudo-infinite focus optics.

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