Bessel beam processing optical system and laser cutting device including the same

Abstract

The Bessel beam processing optical system may include a beam conversion lens that converts a Gaussian laser beam into a first Bessel beam, a condensing lens unit spaced apart from the beam conversion lens in the direction of the beam conversion lens's exit surface and refracting and condensing the first Bessel beam to convert it into a second Bessel beam, and a mask disposed between the beam conversion lens and the condensing lens unit and masking a portion of the first Bessel beam.

Description

Technology Field

[0001] The present invention relates to an optical system and a laser device including the same, and more specifically, to a Bessel beam processing optical system including a mask and a laser cutting device including the same. Background Technology

[0002] A display device is a device that emits light to display images, and various types of laser beams are used in the display device processing process. For example, in the display device processing process, a Bessel beam may be used for cutting the display device. The Bessel beam may include a central lobe having the greatest intensity and a plurality of side lobes surrounding the central lobe.

[0003] When a Bessel beam is used for cutting a display device, the Bessel beam may be irradiated onto the part of the display device that requires cutting. Specifically, the central lobe of the Bessel beam may be irradiated onto the part of the display device that requires cutting. In this case, the side lobes of the Bessel beam may be irradiated onto the part of the display device that does not require cutting (e.g., pixels), which may cause damage to the display device and degrade the light-emitting performance of the display device. The problem to be solved

[0004] One objective of the present invention is to provide a Bessel beam processing optical system capable of removing a portion of the side lobes from a Bessel beam.

[0005] Another objective of the present invention is to provide a laser cutting device comprising the Bessel beam processing optical system.

[0006] However, the objectives of the present invention are not limited by the objectives described above and may be extended in various ways without departing from the spirit and scope of the invention. means of solving the problem

[0007] To achieve one objective of the present invention as described above, a Bessel beam processing optical system according to exemplary embodiments of the present invention may include a beam conversion lens that converts a Gaussian laser beam into a first Bessel beam, a condensing lens unit spaced apart from the beam conversion lens in the direction of the exit surface of the beam conversion lens and refracting and condensing the first Bessel beam to convert it into a second Bessel beam, and a mask disposed between the beam conversion lens and the condensing lens unit and masking a portion of the first Bessel beam.

[0008] In one embodiment, the mask may overlap with a portion of the first depth of focus region of the first Bessel beam.

[0009] In one embodiment, the mask may not overlap with the central lobe of the first Bessel beam.

[0010] In one embodiment, the mask may have a wedge shape in which the thickness decreases from one side to the other.

[0011] In one embodiment, the mask may be a light-reflective mask.

[0012] In one embodiment, the mask may be a light-absorbing mask.

[0013] In one embodiment, the mask can rotate with the optical axis of the beam conversion lens as the axis of rotation.

[0014] In one embodiment, the beam conversion lens may be an axicon lens, a diffractive optical element (DOE), or a spatial light modulator (SLM).

[0015] In one embodiment, the condensing lens unit may include a first focusing lens that refracts and condenses the first Bessel beam to convert it into a ring beam, and a second focusing lens that refracts and condenses the ring beam to convert it into the second Bessel beam.

[0016] In one embodiment, the focus of the first focusing lens may be located between the first focusing lens and the second focusing lens.

[0017] To achieve another objective of the present invention as described above, a laser cutting device according to exemplary embodiments of the present invention includes a light source that generates a Gaussian laser beam and an optical system that converts the properties of the Gaussian laser beam to irradiate a second Bessel beam onto a target substrate, wherein the optical system may include a beam conversion lens that converts the Gaussian laser beam into a first Bessel beam, a focusing lens unit spaced apart from the beam conversion lens in the direction of the exit surface of the beam conversion lens and refracting and focusing the first Bessel beam to convert it into the second Bessel beam, and a mask disposed between the beam conversion lens and the focusing lens unit and masking a portion of the first Bessel beam.

[0018] In one embodiment, the target substrate may be located in the second focal depth region of the second Bessel beam.

[0019] In one embodiment, the target substrate may include a display area, a non-display area surrounding the display area, and a peripheral area surrounding the non-display area.

[0020] In one embodiment, the second Bessel beam may not be irradiated onto the display area of ​​the target substrate.

[0021] In one embodiment, the central lobe of the second Bessel beam can be irradiated at the boundary between the non-display area and the surrounding area.

[0022] In one embodiment, the distance from the central lobe of the second Bessel beam to the display area of ​​the target substrate may be less than 200 μm.

[0023] In one embodiment, the display area and the non-display area may each have rounded corners.

[0024] In one embodiment, the mask can rotate with the optical axis of the beam conversion lens as the axis of rotation.

[0025] In one embodiment, the target substrate may include glass.

[0026] In one embodiment, the thickness of the target substrate may be less than 1 mm. Effects of the invention

[0027] According to exemplary embodiments of the present invention, when a Bessel beam is used for cutting a display device, it is possible to prevent the side lobes of the Bessel beam from being irradiated onto areas of the display device that do not require cutting.

[0028] However, the effects of the present invention are not limited to the effects described above and may be extended in various ways without departing from the spirit and scope of the present invention. Brief explanation of the drawing

[0029] FIG. 1 is a drawing showing a Bessel beam processing optical system according to one embodiment of the present invention. Figure 2 is a diagram illustrating the beam conversion lens of Figure 1. Figure 3 is a cross-sectional view taken along line A0 of Figure 2. Figure 4 is a cross-sectional view taken along line A1 of Figure 1. Figure 5 is a cross-sectional view taken along line A2 of Figure 1. FIG. 6 is a drawing showing one embodiment of the condensing lens part of FIG. 1. FIG. 7 is a drawing showing a laser cutting device according to one embodiment of the present invention. Figure 8 is a drawing showing the target substrate of Figure 7. Figure 9 is a drawing showing the target substrate of Figure 7. Figure 10 is a graph showing the intensity distribution of the second Bessel beam. Figure 11 is an enlarged graph of region 10A of Figure 10. Specific details for implementing the invention

[0030] Hereinafter, a Bessel beam processing optical system according to embodiments of the present invention and a laser cutting device including the same will be described in more detail with reference to the attached drawings. Identical or similar reference numerals are used for identical components in the attached drawings.

[0031] FIG. 1 is a drawing showing a Bessel beam processing optical system according to one embodiment of the present invention.

[0032] Referring to FIG. 1, the Bessel beam processing optical system (1000) may include a beam conversion lens (100), a mask (200), and a condensing lens unit (300).

[0033] A Gaussian laser beam (L1) can be incident on a beam conversion lens (100). The Gaussian laser beam (L1) may be a laser beam having a Gaussian intensity distribution. For example, the Gaussian laser beam (L1) may include an excimer laser beam, a YAG laser beam, a glass laser beam, a YVO4 laser beam, an Ar laser beam, etc. For example, the pulse duration of the Gaussian laser beam (L1) may be a femtosecond or a picosecond.

[0034] The beam conversion lens (100) can convert a Gaussian laser beam (L1) into a first Bessel beam (L2). For example, the beam conversion lens (100) may be an axicon lens, a diffractive optical element (DOE), or a spatial light modulator (SLM) capable of converting a Gaussian beam into a Bessel beam.

[0035] The first Bessel beam (L2) may have a first depth of focus region located adjacent to the exit surface of the beam conversion lens (100). The first depth of focus region may be a region where constructive interference of the first Bessel beam (L2) occurs.

[0036] The first Bessel beam (L2) may have the shape of a ring beam as it moves away from the first depth of focus region. In this case, the diameter of the ring beam may increase as it moves away from the first depth of focus region.

[0037] The condensing lens unit (300) can refract and condense the first Bessel beam (L2) to convert it into a second Bessel beam (L3).

[0038] The second Bessel beam (L3) may have a second depth of focus region at a position spaced a certain distance from the emission surface of the condensing lens unit (300). The second depth of focus region may be a region where constructive interference of the second Bessel beam (L3) occurs.

[0039] In the second depth of focus region, the second Bessel beam (L3) may include a central lobe and a plurality of side lobes surrounding the central lobe. In the present invention, a portion of the first Bessel beam (L2) is masked by a mask (200), and accordingly, a portion of the plurality of side lobes of the second Bessel beam (L3) may be removed.

[0040] The mask (200) may be placed between the beam conversion lens (100) and the condensing lens portion (300). The mask (200) may mask a portion of the first Bessel beam (L2). The mask (200) may have a wedge shape in which the thickness decreases from one side to the other. In one embodiment, the mask may be a light-reflecting mask. In this case, the mask may include copper (Cu), aluminum (Al), etc. In another embodiment, the mask may be a light-absorbing mask.

[0041] In one embodiment, the mask (200) can rotate with the optical axis of the beam conversion lens (100) as the axis of rotation. Accordingly, the position of the part masked by the mask (200) in the first Bessel beam (L2) can be changed.

[0042] Figure 2 is a drawing for explaining the beam conversion lens of Figure 1. Figure 3 is a cross-sectional view taken along line A0 of Figure 2.

[0043] Referring to FIG. 2, a beam conversion lens (100) can convert a Gaussian laser beam (L1) into a first Bessel beam (L2). Specifically, the incident surface of the beam conversion lens (100) into which the Gaussian laser beam (L1) is incident may be a flat surface, and the exit surface may be conical. The Gaussian laser beam (L1) may be refracted in the direction of the vertex of the exit surface to cause constructive interference. Accordingly, the Gaussian laser beam (L1) can be converted into a first Bessel beam (L2).

[0044] The first Bessel beam (L2) may have a first depth of focus region (DF1) located adjacent to the exit surface of the beam conversion lens (100). Constructive interference of the first Bessel beam (L2) may occur in the first depth of focus region (DF1). Due to the constructive interference, the first Bessel beam (L2) may have a greater depth of focus than the Gaussian laser beam (L1).

[0045] Referring to FIG. 3, in the first depth of focus region (DF1), the first Bessel beam (L2) may include a central lobe (CL) and a plurality of side lobes (SL1, SL2, SL3, ..., SLn) surrounding the central lobe (CL). For example, the first Bessel beam (L2) may include a central lobe (CL), a first side lobe (SL1) surrounding the central lobe (CL), a second side lobe (SL2) surrounding the first side lobe, and a third side lobe (SL3) surrounding the second side lobe (SL2). Additionally, the first Bessel beam (L2) may include an nth side lobe (SLn) farthest from the central lobe (CL). The plurality of side lobes (SL1, SL2, SL3, ..., SLn) may be circular in shape.

[0046] There is no limit to the number of side lobes included in the first Bessel beam (L2). In one embodiment, the first Bessel beam (L2) may include two or more side lobes. In another embodiment, the first Bessel beam (L2) may further include a fourth side lobe (not shown), a fifth side lobe (not shown), etc., between the third side lobe (SL3) and the nth side lobe (SLn). The fourth side lobe may surround the third side lobe (SL3), and the fifth side lobe may surround the fourth side lobe.

[0047] The first Bessel beam (L2) may have a maximum intensity at the central lobe (CL). The first Bessel beam (L2) may be canceled out by destructive interference between the central lobe (CL) and the first side lobe (SL1). The maximum intensity of the first Bessel beam (L2) at the first side lobe (SL1) may be smaller than the maximum intensity of the first Bessel beam (L2) at the central lobe (CL). The first Bessel beam (L2) may be canceled out by destructive interference between the first side lobe (SL1) and the second side lobe (SL2). The maximum intensity of the first Bessel beam (L2) at the second side lobe (SL2) may be smaller than the maximum intensity of the first side lobe (SL1) of the first Bessel beam (L2). The first Bessel beam (L2) can be canceled out by destructive interference between the second side lobe (SL2) and the third side lobe (SL3). The maximum intensity of the first Bessel beam (L2) at the third side lobe (SL3) may be smaller than the maximum intensity of the first Bessel beam (L2) at the second side lobe (SL2).

[0048] Figure 4 is a cross-sectional view taken along line A1 of Figure 1.

[0049] Referring to FIG. 4, the mask (200) can mask a portion of the first Bessel beam (L2). Specifically, the mask (200) can overlap with a portion of the first Bessel beam (L2) in the first depth of focus region (DF1 in FIG. 2). In this case, the mask (200) may not overlap with the central lobe (CL) of the first Bessel beam (L2). That is, the central lobe (CL) of the first Bessel beam (L2) may not be masked by the mask (200).

[0050] The mask (200) may partially overlap with a plurality of side lobes (SL1, SL2, SL3, ..., SLn) of the first Bessel beam (L2) in the first depth of focus region. For example, the mask (200) may mask a portion of the second side lobe (SL2), a portion of the third side lobe (SL2), and a portion of the nth side lobe (SLn). Although not shown in the drawing, the mask (200) may also mask a portion of the first side lobe (SL1). That is, the area masked by the mask (200) in the first Bessel beam (L2) can be arbitrarily selected.

[0051] A portion of the plurality of side lobes (SL1, SL2, SL3, ..., SLn) of the first Bessel beam (L2) can be masked by the mask (200). Accordingly, a portion of the second Bessel beam (L3 in FIG. 1) can be removed in the depth of focus region of the second Bessel beam (L3 in FIG. 1).

[0052] Figure 5 is a cross-sectional view taken along line A2 of Figure 1.

[0053] Referring to FIG. 5, FIG. 5 may show a cross-section of the second Bessel beam (L3) in the second depth of focus region of the second Bessel beam (L3). The second depth of focus region may be a region where constructive interference of the second Bessel beam (L3) occurs.

[0054] The second Bessel beam (L3) may include a central lobe (CL') and a plurality of side lobes (SL1', SL2', SL3', ..., SLn') in the second depth of focus region. As described above with reference to FIG. 4, a portion of the side lobes included in the first Bessel beam (L2) may be masked by a mask (200). Accordingly, a portion of the side lobes included in the second Bessel beam (L3) may have a shape cut by a virtual cut line (CTL). For example, a portion of the first side lobe (SL1') may have a shape cut by a virtual cut line (CTL). Additionally, the second side lobe (SL2') to the nth side lobe (SLn') may each have a shape cut by a virtual cut line (CTL).

[0055] In FIG. 5, an embodiment is illustrated in which the first to nth side lobes (SL1', SL2', SL3', ..., SLn') each have a shape cut by a virtual cutting line (CTL), but this is exemplary. That is, the first side lobe (SL1') may have a circular shape, and the second to nth side lobes (SL2', SL3', ..., SLn') may each have a shape cut by a virtual cutting line (CTL). Additionally, the first side lobe (SL1') and the second side lobe (SL2') may each have a circular shape, and the third to nth side lobes (SL3', ..., SLn') may each have a shape cut by a virtual cutting line (CTL).

[0056] The Bessel beam processing optical system (1000) of the present invention allows a mask (200) to mask a portion of the first Bessel beam (L2), and accordingly, a plurality of side lobes (SL1', SL2', SL3', ..., SLn') included in the second Bessel beam (L3) may each have a shape in which a portion is cut by a virtual cut line (CTL). That is, the Bessel beam processing optical system (1000) of the present invention can remove a portion of the plurality of side lobes (SL1', SL2', SL3', ..., SLn') of the second Bessel beam (L3) in the second depth of focus region.

[0057] FIG. 6 is a drawing showing one embodiment of the condensing lens part of FIG. 1.

[0058] Referring to FIG. 6, the condensing lens unit (300) may include a first focusing lens (310) and a second focusing lens (320).

[0059] The first focusing lens (310) can refract and concentrate the first Bessel beam (L2) to convert it into a ring beam (LR). The ring beam (LR) may be a ring-shaped beam having a constant diameter. The second focusing lens (320) can refract and concentrate the ring beam (LR) to convert it into a second Bessel beam (L3). The focal point of the first focusing lens (310) may be located between the first focusing lens (310) and the second focusing lens (320).

[0060] FIG. 7 is a drawing showing a laser cutting device according to one embodiment of the present invention.

[0061] Referring to FIG. 7, the laser cutting device (2000) may include a light source (400), an optical system (500), and a target substrate (600). The optical system (500) may include a beam conversion lens (510), a mask (520), and a focusing lens unit (530).

[0062] The light source (400) may include any device capable of generating a Gaussian laser beam (L1). The Gaussian laser beam (L1) may be a laser beam having a Gaussian intensity distribution. For example, the Gaussian laser beam (L1) may include an excimer laser beam, a YAG laser beam, a glass laser beam, a YVO4 laser beam, an Ar laser beam, etc. For example, the pulse duration of the Gaussian laser beam (L1) may be a femtosecond or a picosecond.

[0063] The beam conversion lens (510) can convert a Gaussian laser beam (L1) into a first Bessel beam (L2). For example, the beam conversion lens (510) may be an axicon lens, a diffractive optical element (DOE), or a spatial light modulator (SLM) capable of converting a Gaussian beam into a Bessel beam.

[0064] The first Bessel beam (L2) may have a first depth of focus region located adjacent to the exit surface of the beam conversion lens (510). The first depth of focus region may be a region where constructive interference of the first Bessel beam (L2) occurs.

[0065] In the first depth of focus region, the first Bessel beam (L2) may include a central lobe (e.g., the central lobe (CL) in FIG. 3) and a plurality of side lobes surrounding the central lobe (e.g., the first to nth side lobes (SL1, SL2, SL3, SLn) in FIG. 3). The central lobe may be a position where the intensity of the first Bessel beam (L2) is maximized by constructive interference of the first Bessel beam (L2). The central lobe may overlap with the optical axis of the beam conversion lens (510).

[0066] The first Bessel beam (L2) may have the shape of a ring beam as it moves away from the first depth of focus region. In this case, the diameter of the ring beam may increase as it moves away from the first depth of focus region.

[0067] The condensing lens unit (530) can refract and condense the first Bessel beam (L2) to convert it into a second Bessel beam (L3). The condensing lens unit (530) may be substantially the same as the condensing lens unit (300) described with reference to FIG. 6.

[0068] The second Bessel beam (L3) may have a second depth of focus region at a position spaced a certain distance from the emission surface of the condensing lens unit (530). The second depth of focus region may be a region where constructive interference of the second Bessel beam (L3) occurs.

[0069] In the second depth of focus region, the second Bessel beam (L3) may include a central lobe and a plurality of side lobes surrounding the central lobe. In the present invention, a portion of the first Bessel beam (L2) is masked by a mask (520), and accordingly, a portion of the plurality of side lobes of the second Bessel beam (L3) may be removed.

[0070] The mask (520) may be placed between the beam conversion lens (510) and the condensing lens portion (530). The mask (520) may mask a portion of the first Bessel beam (L2). The mask (520) may have a wedge shape in which the thickness decreases from one side to the other. In one embodiment, the mask may be a light-reflecting mask. In this case, the mask may include copper (Cu), aluminum (Al), etc. In another embodiment, the mask may be a light-absorbing mask.

[0071] A second Bessel beam (L3) may be irradiated onto the target substrate (600). Specifically, the target substrate (600) may overlap with the second focal depth region of the second Bessel beam (L3). Accordingly, the target substrate (600) may be cut by the second Bessel beam (L3). The target substrate (600) may include glass. The thickness of the target substrate (600) may be less than about 1 mm. Preferably, the thickness of the target substrate (600) may be about 0.5 mm.

[0072] Figure 8 is a drawing showing the target substrate of Figure 7.

[0073] Referring to FIG. 8, the target substrate (600) may include a display area (DA), a non-display area (NDA), and a peripheral area (SA).

[0074] The target substrate (600) may include a plurality of pixels (PXL) in a display area (DA). A pixel (PXL) may include a transistor (not shown) and a light-emitting layer (not shown) electrically connected to the transistor. A pixel (PXL) may receive an electrical signal and emit light of a brightness corresponding to the intensity of the electrical signal. Accordingly, an image can be displayed in the display area (DA) of the target substrate (600).

[0075] When multiple side lobes (SL1, SL2) of the second Bessel beam (L3) are irradiated onto the pixel (PXL), the pixel (PXL) may be damaged. Consequently, the luminous efficiency of the pixel (PXL) may be reduced.

[0076] The target substrate (600) may include a non-display area (NDA) surrounding a display area (DA). The target substrate (600) may not include pixels (PXL) in the non-display area (NDA).

[0077] The target substrate (600) may include a peripheral area (SA) surrounding a non-display area (NDA). The peripheral area (SA) may be an area not included in the final display device. In other words, the display device may include a display area (DA) and a non-display area (NDA) and may not include a peripheral area (SA).

[0078] The second Bessel beam (L3) can be irradiated onto the target substrate (600). The cross-section of the second Bessel beam (L3) irradiated onto the target substrate (600) may be substantially the same as the cross-section of the second Bessel beam (L3) described with reference to FIGS. 1 and FIGS. 5. That is, the second Bessel beam (L3) may have a shape including a plurality of side lobes (SL1, SL2) cut by a virtual cut line (CTL). FIG. 8 illustrates an embodiment in which the second Bessel beam (L3) includes two side lobes (SL1, SL2), but this is exemplary and the number of side lobes included in the second Bessel beam (L3) is not limited thereto. For example, the second Bessel beam (L3) may include three or more side lobes.

[0079] The central lobe (CL) of the second Bessel beam (L3) can be irradiated at the boundary between the non-display area (NDA) and the surrounding area (SA). Accordingly, the second Bessel beam (L3) can cut the target substrate (600) along the boundary between the non-display area (NDA) and the surrounding area (SA). In this case, the distance (D1) from the central lobe (CL) of the second Bessel beam (L3) to the display area (DA) of the target substrate (600) may be less than about 200 μm.

[0080] The second Bessel beam (L3) may not be irradiated onto the display area (DA) of the target substrate (600). Specifically, the side lobes (SL1, SL2) of the second Bessel beam (L3) may not be irradiated onto the display area (DA) of the target substrate (600). For example, a virtual cut-off line (CTL) may overlap with the boundary line between the display area (DA) and the non-display area (NDA). Accordingly, a plurality of pixels (PXL) included in the display area (DA) of the target substrate (600) may not be damaged by the side lobes (SL1, SL2).

[0081] Figure 9 is a drawing showing the target substrate of Figure 7.

[0082] Referring to FIG. 9, the target substrate (600) may include a display area (DA), a non-display area (NDA), and a peripheral area (SA).

[0083] The display area (DA) may be substantially identical to the display area (DA) described with reference to FIG. 8, except for the shape of the corners. Specifically, the corners of the display area (DA) may have a rounded shape.

[0084] The non-display area (NDA) may be substantially identical to the non-display area (NDA) described with reference to FIG. 8, except for the shape of the corners. Specifically, the corners of the non-display area (NDA) may have a rounded shape.

[0085] Referring to FIGS. 7 and 9, the mask (520) can rotate with the optical axis of the beam conversion lens (510) as the axis of rotation. Accordingly, the position of the portion masked by the mask (200) in the first Bessel beam (L2) can change, and in response, the position of the virtual cut lines (e.g., first cut lines to third cut lines (CTL1, CTL2, CTL3)) can change. Specifically, the first cut line (CTL1) can be parallel to the second direction (DR2). The second cut line (CTL2) can be parallel to the first direction (DR1). The third cut line (CTL3) can be at an angle of 45 degrees to the first direction (DR1) and at the same time at an angle of 45 degrees to the second direction (DR2). The positions of each of the first to third cutting lines (CTL1, CTL2, CTL3) are exemplary, and the virtual cutting line can freely rotate with the central lobe of the second Bessel beam (L3) irradiated on the target substrate (600) as the axis of rotation.

[0086] That is, the laser cutting device (2000) of the present invention can adjust the position of the virtual cutting line so that the second Bessel beam (L3) is not irradiated onto the display area (DA) of the target substrate (600), even if the target substrate (600) includes rounded corners in the display area (DA) and the non-display area (NDA), respectively.

[0087] FIG. 10 is a graph showing the intensity distribution of the second Bessel beam. FIG. 11 is a graph showing an enlarged view of region 10A of FIG. 10. In FIG. 10 and FIG. 11, the horizontal axis is the distance from the center of the second Bessel beam, and the vertical axis is the relative intensity of the second Bessel beam.

[0088] Referring to FIGS. 10 and 11, in FIGS. 10 and 11, the first intensity distribution (I1) may represent the intensity distribution of the second Bessel beam (L3) irradiated onto the target substrate (600) from the laser device (2000) of FIG. 7. For example, the first intensity distribution (I1) may be the intensity distribution along the II' line of the second Bessel beam (L3) irradiated onto the target substrate (600) of FIG. 9. In FIGS. 10 and 11, the second intensity distribution (I2) may represent the intensity distribution of the second Bessel beam (L3) irradiated onto the target substrate (600) when there is no mask (520) from the laser device (2000) of FIG. 7.

[0089] Referring to the first intensity distribution (I1) and the second intensity distribution (I2), the second Bessel beam (L3) may have the greatest intensity at the central lobe. As the side lobes of the second Bessel beam (L3) move further away from the central lobe of the second Bessel beam (L3), the maximum intensity at the side lobes of the second Bessel beam (L3) may decrease.

[0090] Referring to FIG. 11, FIG. 11 may be a graph that is an enlarged view of region 10A of FIG. 10. In the first intensity distribution (I1), the intensity of the second Bessel beam (L3) may be approximately 0 in the region located more than about 65 μm away from the center of the second Bessel beam (L3). In contrast, in the second intensity distribution (I2), the intensity of the second Bessel beam (L3) may be greater than 0 even in the region located more than about 65 μm away from the center of the second Bessel beam (L3).

[0091] The laser cutting device (2000) of the present invention can have a mask (520) that masks a portion of the first Bessel beam (L2), and accordingly, a plurality of side lobes of the second Bessel beam (L3) can each have a shape in which a portion is cut by a virtual cutting line (CTL). The laser cutting device (2000) of the present invention can adjust the position of the virtual cutting line (CTL) so that a plurality of side lobes of the second Bessel beam (L3) are not irradiated onto the display area (DA) of the target substrate (600).

[0092] Although the foregoing description refers to exemplary embodiments of the present invention, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the invention as set forth in the following claims. Industrial applicability

[0093] The Bessel beam processing optical system of the present invention and the laser cutting device including the same can be used in various display device manufacturing processes. For example, the Bessel beam processing optical system of the present invention and the laser cutting device including the same can be used in manufacturing processes for numerous display devices, such as display devices for vehicles, ships, and aircraft, portable display devices, display devices for exhibition or information transmission, medical display devices, etc. Explanation of the symbols

[0094] 1000: Bessel beam processing optical system 100, 510: Beam conversion lens 200, 520: Mask 300, 530: Concentrating lens part L1: Gaussian laser beam L2: First Bessel beam L3 : 2nd Bessel Beam 400 : Light Source 600 : Target substrate DA : Display area NDA: Non-display area SA: Surrounding area PXL : Pixels

Claims

Claim 1 A Bessel beam processing optical system comprising: a beam conversion lens that converts a Gaussian laser beam into a first Bessel beam; a condensing lens unit spaced apart from the beam conversion lens in the direction of the exit surface of the beam conversion lens and refracting and condensing the first Bessel beam to convert it into a second Bessel beam; and a mask disposed between the beam conversion lens and the condensing lens unit and masking a portion of the first Bessel beam, wherein the mask overlaps a portion of the first depth of focus region of the first Bessel beam and the mask rotates with the optical axis of the beam conversion lens as the axis of rotation. Claim 2 delete Claim 3 A Bessel beam processing optical system according to claim 1, characterized in that the mask does not overlap with the central lobe of the first Bessel beam. Claim 4 A Bessel beam processing optical system according to claim 1, characterized in that the mask has a wedge shape in which the thickness decreases from one side to the other. Claim 5 A Bessel beam processing optical system characterized in that, in claim 4, the mask is a light-reflection mask. Claim 6 A Bessel beam processing optical system characterized in that, in claim 4, the mask is a light-absorbing mask. Claim 7 delete Claim 8 A Bessel beam processing optical system according to claim 1, characterized in that the beam conversion lens is an axicon lens, a DOE (diffractive optical element), or a spatial light modulator (SLM). Claim 9 A Bessel beam processing optical system according to claim 1, wherein the condensing lens portion comprises: a first focusing lens that refracts and condenses the first Bessel beam to convert it into a ring beam; and a second focusing lens that refracts and condenses the ring beam to convert it into the second Bessel beam. Claim 10 A Bessel beam processing optical system according to claim 9, characterized in that the focus of the first focusing lens is located between the first focusing lens and the second focusing lens. Claim 11 A laser cutting device comprising: a light source that generates a Gaussian laser beam; and an optical system that converts the properties of the Gaussian laser beam to irradiate a second Bessel beam onto a target substrate, wherein the optical system comprises: a beam conversion lens that converts the Gaussian laser beam into a first Bessel beam; a condensing lens unit spaced apart from the beam conversion lens in the direction of the exit surface of the beam conversion lens and refracting and condensing the first Bessel beam to convert it into the second Bessel beam; and a mask disposed between the beam conversion lens and the condensing lens unit and masking a portion of the first Bessel beam, wherein the mask overlaps a portion of the first depth of focus region of the first Bessel beam and the mask rotates with the optical axis of the beam conversion lens as the axis of rotation. Claim 12 A laser cutting device according to claim 11, characterized in that the target substrate is located in the second focal depth region of the second Bessel beam. Claim 13 A laser cutting device according to claim 11, characterized in that the target substrate comprises a display area, a non-display area surrounding the display area, and a peripheral area surrounding the non-display area. Claim 14 A laser cutting device according to claim 13, characterized in that the second Bessel beam is not irradiated onto the marked area of ​​the target substrate. Claim 15 A laser cutting device according to claim 13, characterized in that the central lobe of the second Bessel beam is irradiated at the boundary between the non-display area and the surrounding area. Claim 16 A laser cutting device according to claim 15, characterized in that the distance from the central lobe of the second Bessel beam to the display area of ​​the target substrate is less than 200 μm. Claim 17 A laser cutting device according to claim 13, wherein each of the display area and the non-display area has rounded corners. Claim 18 delete Claim 19 A laser cutting device according to claim 11, characterized in that the target substrate comprises glass. Claim 20 A laser cutting device according to claim 11, characterized in that the thickness of the target substrate is less than 1 mm.

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