KR102503846B1 - Laser cutting apparatus - Google Patents

Abstract

The laser cutting device includes a laser module for generating and emitting a laser beam in a first direction, a mirror for reflecting the laser beam in a second direction crossing the first direction, a condensing lens for transmitting and condensing the laser reflected from the mirror, It includes a rotating plate that transmits laser provided from a condensing lens and changes the focus of the laser, and a support on which a substrate receiving the laser transmitted through the rotating plate is disposed, and the focal point of the laser is disposed inside the substrate.

Description

Laser cutting device {LASER CUTTING APPARATUS}

The present invention relates to a laser cutting device, and more particularly, to a laser cutting device capable of improving process efficiency.

Electronic devices such as smart phones, digital cameras, notebook computers, navigation devices, and smart TVs that provide images to users include display devices for displaying images. The display device includes a display panel for generating and displaying images and a window disposed above the display panel to protect the display panel.

The display panel and window may include a glass substrate. For example, the display panel may include a glass substrate and a plurality of pixels disposed on the glass substrate. Also, the window may include a tempered glass substrate to protect the display panel from scratches.

Such a glass substrate must be cut to fit the size of the display device. In general, a glass substrate is manufactured by cutting a large-area glass substrate into a plurality of unit substrates to improve yield.

A scribing wheel may be used to cut the substrate. Unit substrates may be manufactured by forming cracks in the mother substrate while the scribing wheel rotates in contact with the substrate, and then pressurizing and cutting the portion where the crack is formed. However, the substrate cutting method using a wheel has a problem in that the cutting surface is not constant or smooth because the substrate is cut by physical force.

In order to solve this problem, a method of cutting a substrate using a laser without using a wheel has been used. In the case of using a laser, after the laser is irradiated to the substrate, cracks are formed as the portion of the substrate heated by the laser is cooled. The substrate may be cut by applying a predetermined external force to the portion where the crack is formed.

An object of the present invention is to provide a laser cutting device capable of improving process efficiency.

A laser cutting device according to an embodiment of the present invention includes a laser module for generating and emitting a laser in a first direction, a mirror for reflecting the laser in a second direction crossing the first direction, and a laser reflected from the mirror. It includes a condensing lens for condensing while transmitting, a rotating plate for varying the focus of the laser while transmitting the laser provided from the condensing lens, and a support on which a substrate receiving the laser transmitted through the rotating plate is disposed, and the focus of the laser is placed inside the board.

The laser has a wavelength range of 300 nm to 1064 nm.

The rotating plate includes a plurality of plates for varying the focus of the laser while transmitting the laser provided from the condensing lens, and a plurality of open portions disposed between the plates and formed in empty spaces between the plates. The laser passing through the openings has a first focal point, and the laser passing through the plates is refracted by the plates and has a second focal point.

The first focal point is disposed at a predetermined area inside the substrate adjacent to the upper surface of the substrate, and the second focal point is disposed at a predetermined area within the substrate adjacent to a lower surface of the substrate.

The rotating plate is rotated about the center of the rotating plate as an axis, and the laser condensed by the condensing lens repeatedly passes through the plates and the open portions.

The rotating plate rotates in one of clockwise and counterclockwise directions.

The support unit moves the substrate so that the laser is provided from one side of the substrate to the other side of the substrate.

A plurality of first dots are continuously formed on a portion of the substrate corresponding to the first focal point, a plurality of second dots are continuously formed on a portion of the substrate corresponding to the second focal point, and the first and second focal points are continuously formed. Dots are portions of the substrate heated by the laser at locations where the first and second focal points are disposed.

The first and second dots overlap each other when viewed from above, and an external force is applied to a crack formed by cooling the first and second dots to cut the substrate.

The plates include glass.

The rotating plate has a circular shape.

The plates have a fan shape, and the contact points of the two radii of the fan shape of the plates are disposed at the center of the rotating plate.

The open portions and the plates have a 1/4 circle shape.

The open portions have the same size as each other, and the plates have the same size as each other.

The laser cutting device according to an embodiment of the present invention can improve process efficiency by reducing process time by forming a plurality of cracks having different heights on a mother substrate and arranged in parallel with the substrate without being driven in the vertical direction. there is.

1A and 1B are views schematically showing the configuration of a laser cutting device according to an embodiment of the present invention.
2 is a diagram for explaining the refraction of light according to Snell's law.
3A and 3B are views showing a plan configuration of the rotation plate shown in FIGS. 1A and 1B.
FIG. 4 is a view showing dots formed on a substrate by the laser cutting device shown in FIGS. 1A and 1B.
5A and 5B are diagrams illustrating a state in which a mother substrate is cut using the laser cutting device shown in FIGS. 1A and 1B .
6 is a view showing a rotating plate of a laser cutting device according to another embodiment of the present invention.
FIG. 7 is a diagram illustrating dots formed on a substrate using the rotating plate shown in FIG. 6 .

Advantages and features of the present invention, and methods for achieving them, will become clear with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, only the present embodiments make the disclosure of the present invention complete, and those skilled in the art in the art to which the present invention belongs It is provided to fully inform the person of the scope of the invention, and the invention is only defined by the scope of the claims. Like reference numbers designate like elements throughout the specification.

When an element or layer is referred to as being "on" or "on" another element or layer, it is not only directly on the other element or layer, but also when another layer or other element is intervening therebetween. All inclusive. On the other hand, when an element is referred to as “directly on” or “directly on”, it indicates that another element or layer is not intervened. “And/or” includes each and every combination of one or more of the recited items.

The spatially relative terms "below", "beneath", "lower", "above", "upper", etc. It can be used to easily describe the correlation between elements or components and other elements or components. Spatially relative terms should be understood as encompassing different orientations of elements in use or operation in addition to the orientations shown in the figures. Like reference numbers designate like elements throughout the specification.

Although first, second, etc. are used to describe various elements, components and/or sections, it is needless to say that these elements, components and/or sections are not limited by these terms. These terms are only used to distinguish one element, component or section from another element, component or section. Accordingly, it goes without saying that the first element, first element, or first section referred to below may also be a second element, second element, or second section within the spirit of the present invention.

Embodiments described herein will be described with reference to plan and cross-sectional views, which are ideal schematic diagrams of the present invention. Accordingly, the shape of the illustrative drawings may be modified due to manufacturing techniques and/or tolerances. Therefore, embodiments of the present invention are not limited to the specific shapes shown, but also include changes in shapes generated according to manufacturing processes. Accordingly, the regions illustrated in the drawings have schematic properties, and the shapes of the regions illustrated in the drawings are intended to illustrate a specific shape of a region of a device and are not intended to limit the scope of the invention.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

1A and 1B are views schematically showing the configuration of a laser cutting device according to an embodiment of the present invention. 2 is a diagram for explaining the refraction of light according to Snell's law.

1A and 1B, a laser cutting device 100 according to an embodiment of the present invention includes a laser module 200, a mirror 300, a condensing lens 400, a rotating plate 500, and a support 700. includes

The laser module 200 generates a laser R and emits the laser R in a first direction D1. The laser R may be an ultraviolet laser having a wavelength range of 300 nm to 1064 nm. However, it is not limited thereto, and various lasers such as a carbon dioxide laser, a semiconductor laser, or an excimer laser may be used as the laser.

The mirror 300 is disposed horizontally with the laser module 200 in the first direction D1 and receives the laser R emitted from the laser module 200 . The mirror 300 is disposed to be inclined with respect to the first direction D1, and the inclination angle of the mirror 300 is such that light traveling in the first direction D1 is disposed in a second direction crossing the first direction D1 ( It can be set to an angle that can be changed with D2). For example, the first direction D1 may be a horizontal direction, and the second direction D2 may be a downward direction.

The mirror 300 reflects the laser R provided from the laser module 200 to change the traveling direction of the laser R to the second direction D2. The laser R reflected by the mirror 300 is provided to the condensing lens 400 .

The condensing lens 400 is disposed under the mirror 300, and receives the laser R that is reflected from the mirror 300 and travels in the second direction D2. The condensing lens 400 serves to converge light toward a predetermined focal point while transmitting light. Accordingly, the laser R may be focused toward a predetermined focal point by the condensing lens 400 while passing through the condensing lens 400 . Illustratively, a convex lens may be used as the condensing lens 400 .

The rotation plate 500 is disposed under the condensing lens 400 and receives the laser R transmitted through the condensing lens 400 . Rotating plate 500 has a circular shape. A specific shape of the rotating plate 500 will be described in detail with reference to FIGS. 1A and 1B. The rotating plate 500 may change the focus of the laser R that is condensed through the condensing lens 400 .

Specifically, the rotating plate 500 includes a plurality of open portions 510 and a plurality of plates 520 . The open portions 510 are disposed between the plates 520 and are substantially empty spaces. The plates 520 include a material capable of transmitting light. For example, the plates 520 may include glass.

The plates 520 may change the focus of the laser R by varying the optical path length of the laser R passing through the plates 520 . The optical path length is defined as the distance between the starting point of the laser R passing through the condensing lens 400 and the focal point of the laser R. As the optical path length becomes longer, the focal point of the laser R may be farther from the condensing lens 400, and as the optical path length becomes shorter, the focal point of the laser R may be closer to the condensing lens 400.

Hereinafter, the focal point of the laser R passing through the open portions 510 is defined as a first focal point F1, and the focal point of the laser R passing through the plates 520 is defined as a second focal point F2. do.

The focus of the light condensed by the condensing lens 400 may be set to the first focus F1. Since the open portions 510 are substantially empty spaces, the focus of the laser R passing through the open portions 510 may also be set to the first focus point F1, as shown in FIG. 1A.

The plates 520 change the optical path length of the laser R passing through the plates 520 to be longer than the optical path length of the laser R passing through the openings 510 . The laser R transmitted through the condensing lens 400 and provided to the plates 520 is refracted by the plates 520, so that the optical path length of the laser R becomes longer. This reason will be explained with reference to FIG. 2 below.

Referring to FIG. 2 , glass G is disposed on the air layer AR, and first light L1 and second light L2 are radiated toward the glass G. When the first light L1 and the second light L2 travel straight without being refracted, they may proceed to meet at the virtual focal point VF as shown in the dotted line shown in FIG. 2 .

The refractive index of the glass G is greater than that of the air layer AR. In this case, according to Snell's law, when the first light L1 and the second light L2 pass through the glass G, they are refracted. Specifically, when the first light L1 and the second light L2 propagate from the air layer AR on the glass G to the glass G, the air layer AR on the glass G and the glass Based on the boundary of (G), the angle of refraction of the first light L1 is smaller than the incident angle of the first light L1.

When the first light L1 and the second light L2 are provided from the glass G to the air layer AR under the glass G, the glass G and the air layer AR under the glass G Based on the boundary of ), the angle of refraction of the first light L1 is greater than the angle of incidence of the first light L1. The second light L2 is also refracted substantially the same as the first light L1.

Therefore, as shown in FIG. 2 , since the optical path lengths of the first light L1 and the second light L2 passing through the glass G become longer, the first light L1 and the second light L2 ) can be met at the actual focal point RF disposed lower than the virtual focal point VF.

Referring back to FIGS. 1A and 1B , the focal point of the laser R transmitted through the plates 520 may be set to a second focal point F2 distant from the condensing lens 400 than the first focal point F1. . As a result, as shown in FIG. 1B, the second focal point F2 may be disposed lower than the first focal point F1.

The support part 700 is disposed under the rotating plate 500, and the substrate 600 is disposed on the support part 700. The substrate 600 may be a glass substrate used for a display panel or a glass substrate used for a window. The substrate 600 has a planar shape parallel to the first direction D1. The second direction D2 may be defined as a direction perpendicular to the plane of the substrate 600 .

The first focal point F1 of the laser beam R transmitted through the condensing lens 400 and condensed may be disposed inside the substrate 600 . For example, as shown in FIG. 1A , after passing through the condensing lens 400, the first focal point F1 of the laser R passing through the open portions 510 is adjacent to the upper surface of the substrate 600. It may be disposed in a predetermined area inside the substrate 600 .

The second focal point F2 may be disposed below the first focal point F1 , and the second focal point F2 may be disposed inside the substrate 600 . For example, as shown in FIG. 1B, after passing through the condensing lens 400, the second focal point F2 of the laser R passing through the plates 520 is adjacent to the lower surface of the substrate 600. It may be disposed in a predetermined area inside the substrate 600 .

3A and 3B are views showing a plan configuration of the rotation plate shown in FIGS. 1A and 1B.

3A and 3B also show a transmission state of the laser R passing through the rotating plate 500 for convenience of description.

Referring to FIGS. 3A and 3B , the rotating plate 500 has a circular shape and can rotate around the center of the rotating plate 500 as an axis. For example, the rotary plate 500 may rotate clockwise, but is not limited thereto, and the rotary plate 500 may rotate counterclockwise.

The open portions 510 and the plates 520 of the rotation plate 500 may have a fan shape, and the contact points of the two radii of the fan shape of the plates 520 may be disposed at the center of the rotation plate 500 . Each of the open portions 510 and the plates 520 may have a 1/4 circle shape. The two open portions 510 may have the same size as each other, and the two plates 520 may have the same size as each other.

The number of plates 520 is set to two and the number of open portions 510 is set to two, but the number of plates 520 and the number of open portions 510 are not limited thereto and may be set in various ways. can

As the rotating plate 500 is rotated, the laser R can repeatedly pass through the open portions 510 and the plates 520, and as a result, the focus of the laser R is shifted to the first focus point F1 and the second focus point F1. It can be repeatedly changed to focus (F2).

FIG. 4 is a view showing dots formed on a substrate by the laser cutting device shown in FIGS. 1A and 1B. 5A and 5B are diagrams illustrating a state in which a mother substrate is cut using the laser cutting device shown in FIGS. 1A and 1B .

Referring to FIG. 4 , the support 700 on which the substrate 600 is disposed may move in a third direction D3 intersecting the first direction D1 on a plane. For example, the support 700 may move the substrate 600 in the third direction D3 so that the laser R is provided from one side of the substrate 600 to the other side of the substrate 600 .

The substrate 600 moves in the third direction D3, and the focus of the laser R passing through the rotating plate 500 is repeatedly changed to a first focus point F1 and a second focus point F2. Since the substrate 600 moves in the third direction D3, the first dots DT1 are formed on the substrate 600 by the first focal point F1, and the substrate 600 is formed by the second focal point F2. ), the second dots DT2 are formed.

The first dots DT1 are formed on a portion of the substrate 600 corresponding to the first focal point F1, and the second dots DT2 are formed on a portion of the substrate 600 corresponding to the second focal point F2. is formed in The first and second dots DT1 and DT2 are substantially portions of the substrate 600 heated by the laser at positions where the first and second focal points F1 and F2 of the laser R are disposed, They are arranged to overlap each other when viewed from above.

The first dots DT1 are disposed in a predetermined area inside the substrate 600 adjacent to the upper surface of the substrate 600 and are arranged in the third direction D3. The first dots DT1 are continuously formed and may be disposed to partially overlap each other.

The second dots DT2 are disposed in a predetermined area inside the substrate 600 adjacent to the lower surface of the substrate 600 and are arranged in the third direction D3. The second dots DT2 are continuously formed and may be arranged to partially overlap each other.

The first dots DT1 are cooled, and cracks (hereinafter referred to as first cracks) are formed by the first dots DT1 in the third direction D3. The second dots DT2 are cooled, and cracks (hereinafter, referred to as second cracks) are formed by the second dots DT2 in the third direction D3.

The second crack is disposed below the first crack, and the first and second cracks extend in the third direction D3. The substrate 600 may be cut by applying a predetermined external force to the portion where the first and second cracks are formed. When two cracks are formed than when one crack is formed, the substrate can be easily cut.

Referring to FIGS. 5A and 5B , first and second dots DT1 and DT2 are formed on the mother substrate MS by the laser cutting device 100 to form first and second cracks. . As shown in FIG. 5A , the first and second cracks may divide the mother substrate MS into four regions. Four unit substrates US may be manufactured by cutting the mother substrate MS along the first and second cracks.

When the rotary plate 500 is not used, the laser module 200, the mirror 300, and the condensing lens 400 are moved up and down so that the laser R has a first focus point F1 and a second focus point F2. should be repeatedly moved to .

Since the laser module 200, the mirror 300, and the condensing lens 400 repeatedly move up and down, the process time may increase. In addition, since the laser module 200, the mirror 300, and the condensing lens 400 change the focus of the laser R while moving, the focus of the laser R may not be accurately formed at a desired position.

In an embodiment of the present invention, the laser module 200, the mirror 300, and the condensing lens 400 are fixed, and the rotation plate for changing the focus of the laser R is between the condensing lens 400 and the substrate 600. 500 is placed. Accordingly, the process time is shortened, and the focal point of the laser R can be more accurately positioned at a desired location.

As a result, the laser cutting device 100 according to an embodiment of the present invention can improve process efficiency by reducing process time during a substrate cutting process.

6 is a view showing a rotating plate of a laser cutting device according to another embodiment of the present invention.

Except for the configuration of the rotating plate, a laser cutting device according to another embodiment of the present invention has the same configuration as the laser cutting device 100 shown in FIGS. 1A and 1B.

Referring to FIG. 6 , a rotating plate 500_1 having a circular shape includes a plurality of first open portions 510_1 , a plurality of first plates 520_1 , and a plurality of second plates 530 . The first open portions 510_1 are empty spaces, and the first and second plates 520_1 and 530 include a material capable of transmitting light.

The first open portions 510_1 are disposed between the first and second plates 520_1 and 530 adjacent to each other. For example, two first plates 520_1, two second plates 530, and four first open parts 510_1 may be disposed on the rotating plate 500_1. The first plates 520_1 may be disposed to face each other based on the center of the rotating plate 500_1. The second plates 530 may be disposed to face each other based on the center of the rotation plate 500_1.

The open portions 510_1 and the first and second plates 520_1 and 530 of the rotation plate 500_1 may have a fan shape, and a contact point of two radii of the fan shape may be disposed at the center of the rotation plate 500_1. The open portions 510_1 and the first and second plates 520 and 530 may each have a 1/8 circular shape. The four open portions 510_1 may have the same size, the two first plates 520_1 may have the same size, and the two second plates 530 may have the same size.

The first plates 520_1 and the second plates 530 are formed of materials having different refractive indices, so that the focus of the laser can be set differently. For example, the first plates 520_1 change the optical path length of the laser passing through the first plates 520_1 to be longer than the optical path length of the laser passing through the open portions 510_1 . The second plates 530 change the optical path length of the laser passing through the second plates 530 to be longer than the optical path length of the laser passing through the first plates 520_1 .

The focus of the laser passing through the open portions 510_1 is set to the first focus. The focus of the laser passing through the first plates 520_1 is set to the second focus. The focus of the laser passing through the second plates 530 is set to the third focus.

Although not shown, the first, second, and third focal points are disposed inside the substrate. The first focal point is disposed at a predetermined area inside the substrate adjacent to the upper surface of the substrate, and the third focal point is disposed at a predetermined area within the substrate adjacent to the lower surface of the substrate. The second focal point is disposed in a predetermined area inside the substrate between the first focal point and the third focal point. That is, the second focal point is disposed below the first focal point, and the third focal point is disposed below the second focal point.

FIG. 7 is a diagram illustrating dots formed on a substrate using the rotating plate shown in FIG. 6 .

Referring to FIG. 7 , the substrate 600_1 disposed on the support 700_1 moves in the third direction D3, and the focal points of the laser R passing through the rotating plate 500 are the first focal point and the second focal point. focal point, and the third focal point are repeatedly varied. First dots DT1_1 are formed by the first focal point, second dots DT2_1 are formed by the second focal point, and third dots DT3 are formed by the third focal point.

The first dots DT1_1 are disposed in a predetermined area inside the substrate 600_1 adjacent to the upper surface of the substrate 600_1 and are arranged in the third direction D3. The third dots DT3 are disposed in a predetermined area inside the substrate 600_1 adjacent to the lower surface of the substrate 600_1 and are arranged in the third direction D3. The second dots DT2_1 are disposed in a predetermined area inside the substrate 600_1 between the first dots DT1_1 and the third dots DT3 and are arranged in the third direction D3.

The first dots DT1_1 , the second dots DT2_1 , and the third dots DT3 are formed consecutively and are arranged to partially overlap each other. Three cracks are formed by the first, second, and third dots DT1_1, DT2_1, and DT3 so that the substrate 600_1 may be cut. As the number of cracks increases, the substrate 600_1 can be cut more easily.

In another embodiment of the present invention, the laser module, the mirror, and the condensing lens are fixed, and the rotating plate 500_1 for varying the focus of the laser R is disposed between the condensing lens and the substrate 600_1. Accordingly, the process time is shortened, and the focal point of the laser R can be more accurately positioned at a desired location.

As a result, the laser cutting device according to another embodiment of the present invention can improve process efficiency by reducing process time during a substrate cutting process.

Illustratively, in the embodiment of the present invention, a laser cutting device in which two or three focal points are formed has been described, but depending on the configuration of the rotating plate, the number of focal points may be greater than this. For example, if more than two types of plates are disposed on the rotating plate, and more than two types of plates change the optical path length differently, more than three focal points may be formed.

Although described with reference to the above embodiments, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the present invention described in the claims below. You will be able to. In addition, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, and all technical ideas within the scope of the following claims and their equivalents should be construed as being included in the scope of the present invention. .

100: laser cutting device 200: laser module
300: mirror 400: concentrating device
500, 500_1: rotating plate 600, 600_1: substrate
700, 700_1: support part 510, 510_1: open part
520: plate 520_1: first plate
530: second plate

Claims (16)

A laser module for generating and emitting a laser in a first direction;
a mirror for reflecting the laser beam in a second direction crossing the first direction;
a condensing lens for condensing while transmitting the laser reflected from the mirror;
a rotating plate for varying the focus of the laser while transmitting the laser provided from the condensing lens; and
A support portion on which a substrate receiving the laser transmitted through the rotating plate is disposed;
The focal point of the laser is disposed inside the substrate,
The rotating plate,
a plurality of plates for varying the focus of the laser while transmitting the laser provided from the condensing lens; and
It is disposed between the plates and includes a plurality of open portions formed in empty spaces between the plates,
Wherein the laser is refracted when passing through the plurality of plates and is not refracted when passing through the plurality of open portions. According to claim 1,
The laser cutting device having a range of 300nm to 1064nm wavelength. According to claim 1,
The laser passing through the openings has a first focus, and the laser passing through the plates is refracted at the plates and has a second focus. According to claim 3,
The first focal point is disposed in a predetermined area inside the substrate adjacent to the upper surface of the substrate, and the second focal point is disposed in a predetermined area inside the substrate adjacent to the lower surface of the substrate Laser cutting device. According to claim 4,
The laser cutting device of claim 1 , wherein the rotary plate is rotated about the center of the rotary plate as an axis, and the laser condensed by the condensing lens repeatedly passes through the plates and the open portions. According to claim 5,
The rotating plate is a laser cutting device that rotates in any one of clockwise and counterclockwise directions. According to claim 5,
The support unit, the laser cutting device for moving the substrate so that the laser is provided from one side of the substrate to the other side of the substrate. According to claim 7,
A plurality of first dots are continuously formed on a portion of the substrate corresponding to the first focal point, and a plurality of second dots are continuously formed on a portion of the substrate corresponding to the second focal point, 2 dots are the part of the substrate heated by the laser at the position where the first and second focal points are disposed. According to claim 8,
The first and second dots overlap each other when viewed from above, and an external force is applied to a crack formed by cooling the first and second dots to cut the substrate. According to claim 3,
The plates are a laser cutting device comprising glass. According to claim 3,
The rotating plate is a laser cutting device having a circular shape. According to claim 11,
The plates have a fan shape, and the contact point of the two radii of the fan shape of the plates is disposed at the center of the rotating plate. According to claim 12,
The open parts and the plates have a 1/4 circle shape laser cutting device. According to claim 3,
The open parts have the same size as each other, and the plates have the same size as each other. According to claim 1,
The rotating plate,
a plurality of first plates for varying the focus of the laser while transmitting the laser provided from the condensing lens;
a plurality of second plates that transmit the laser provided from the condensing lens and vary the focus of the laser differently from that of the first plates; and
a plurality of open portions disposed between first and second plates adjacent to each other and formed as empty spaces between the first and second plates adjacent to each other;
The laser passing through the openings has a first focus, the laser passing through the first plates is refracted at the first plate and has a second focus, and the laser passing through the second plates has a second focus. A laser cutting device that is refracted at the plates and has a third focal point. According to claim 15,
The first focal point is disposed in a predetermined area inside the substrate adjacent to the upper surface of the substrate, the third focal point is disposed in a predetermined area inside the substrate adjacent to the lower surface of the substrate, and the second focal point is disposed in the predetermined area adjacent to the lower surface of the substrate. A laser cutting device disposed in a predetermined area inside the substrate between the first focal point and the second focal point.

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