CN117300333A

CN117300333A - Laser processing method applied to manufacturing display device

Info

Publication number: CN117300333A
Application number: CN202310762839.8A
Authority: CN
Inventors: 李浚政; 元载雄; 李奉燉; 朴大星
Original assignee: Meere Co Inc
Current assignee: Meere Co Inc
Priority date: 2022-06-29
Filing date: 2023-06-27
Publication date: 2023-12-29

Abstract

The present invention discloses a laser processing method for forming an open space in a display panel to mount a front surface constituent element, a method of irradiating laser stepwise to minimize laser damage and a method of irradiating laser discontinuously but in a manner of setting a pause interval are disclosed according to an embodiment, and the laser processing method includes a method for removing a cone shape occurring and a method for removing micro cracks generated at the time of laser processing.

Description

Laser processing method applied to manufacturing display device

Technical Field

The present disclosure provides a laser processing method applied to manufacturing a display device.

Background

In order to raise the screen ratio to the limit, a front-end component such as a front-end camera, an illuminance sensor, a microphone, and a speaker is disposed in a partial region of a screen included in a smart phone (smart phone), a tablet, a smart television (smart TV), a smart monitor (smart monitor), a smart watch (smart watch), and the like. In order to arrange these front-end components, it is necessary to form an open space (e.g., punched hole) for exposing the corresponding components in the display panel. Such an open space can be realized by forming a punched hole or the like in the display panel using a laser processing method.

Korean laid-open patent publication No. 10-2021-0136946, which is the applicant's laid-open patent, discloses a laser processing system and a laser processing method. However, when an open space is formed on a display panel by such a general laser processing method, heat generated by laser may cause thermal damage to a laser irradiated portion. The thermally damaged portion may develop into cracks due to external impact or bending, and in this case, there is a problem that the resulting final product is poor. Accordingly, there is a need for a laser processing method that minimizes thermal damage generated during laser processing, maximizes the picture ratio of a display panel, and prevents the occurrence of defects in the final product due to laser processing.

Disclosure of Invention

Technical problem to be solved by the invention

Various embodiments of a laser processing method applied to manufacturing a display device are disclosed. The technical problems to be solved by the present embodiment are not limited to the above-described technical problems, and other technical problems can be deduced from the following embodiments.

Technical proposal

As a means for solving the above-described technical problem, a first aspect of the present disclosure provides a laser processing method for irradiating a laser beam output from a laser oscillator to a workpiece with an optical unit including a mirror and a lens to form an open space in the workpiece, the laser processing method comprising: a step of preparing a workpiece having a machining surface on one surface; a step of oscillating the laser by operating a laser oscillator, and selecting a processing position by the optical unit; a first processing step of irradiating a first laser beam along a first path on a processing surface of the object to be processed; a second processing step of irradiating a second laser beam along a second path on a processing surface of the object to be processed; and a step of forming an open space in the workpiece by removing a dummy formed after the laser processing.

A second aspect of the present disclosure provides a laser processing method of irradiating a laser beam output from a laser oscillator to a workpiece to form an open space in the workpiece using an optical unit including a mirror and a lens, wherein a processing surface of the workpiece includes a sample region included in a final product, a virtual region not included in the final product, and a processing region corresponding to a boundary between the sample region and the virtual region, the laser processing method including: a step of preparing a workpiece having a machining surface on one surface; a step of oscillating the laser by operating a laser oscillator, and selecting a processing position by the optical unit; continuously and repeatedly irradiating laser light to the processing region and different positions on a virtual region adjacent to the processing region; and a step of forming an open space in the object by removing the dummy formed after the laser processing.

Advantageous effects

According to the means for solving the above-described problems of the present disclosure, damage caused by laser light when forming an open space in a display panel can be minimized. And, as damage caused by the laser is minimized, the risk of cracking in the final product can be reduced, and the reject ratio of the final product can be reduced.

Also, according to the means for solving the problems of the present disclosure, the taper of the open space generated by the laser processing method is minimized or removed, thereby having the effect of maximizing the picture ratio of the display panel and enabling realization of a large-area picture.

Further, according to the means for solving the problems of the present disclosure, microcracks generated on the processing surface by the laser processing method are removed, and thus the effect of preventing the development of microcracks in advance to affect the effective area and reducing the defective rate due to the cracks is obtained.

Drawings

Fig. 1 shows several forms of an open space formed in a display panel of a smart phone.

Fig. 2 is a conceptual diagram illustrating contents forming an open space in a display panel.

Fig. 3 is a diagram illustrating a laser processing system according to an embodiment of the present invention.

Fig. 4 shows a laser processing method according to an embodiment of the present invention.

Fig. 5 shows a laser processing method according to another embodiment of the present invention.

Fig. 6 shows a laser processing method according to a further embodiment of the invention.

Fig. 7 shows a laser processing method according to a further embodiment of the present invention.

Fig. 8 shows a laser processing method according to a further embodiment of the present invention.

Fig. 9 shows a laser processing method according to a further embodiment of the present invention.

Fig. 10 shows a laser processing method according to a further embodiment of the present invention.

Fig. 11 shows a laser processing method according to a further embodiment of the present invention.

Fig. 12 is a picture of a punched hole according to a comparative example and a punched hole processed according to the laser processing method of fig. 11.

Fig. 13 shows a laser processing method according to a further embodiment of the present invention.

Fig. 14 is a photograph of a punched hole according to a comparative example and a punched hole processed according to the laser processing method of fig. 12.

Fig. 15 shows a laser processing method according to an embodiment of the present invention.

Fig. 16 shows a laser processing method according to another embodiment of the present invention.

Fig. 17 is a photograph of a portion where microcracks are generated by laser processing after the laser processing step.

Fig. 18 shows a laser processing method according to an embodiment of the present invention.

Fig. 19 is a graph comparing rigidity and surface roughness of a crack surface subjected to laser polishing using the above laser.

Description of the reference numerals

10: display panel

TH: open space

11: substrate base

12: drive element layer

13: display element layer

14: cover layer

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. The invention may, however, be embodied in many different forms and is not limited to the embodiments described herein. And for the purpose of clearly illustrating the present invention in the drawings, parts irrelevant to the description are omitted, and like parts are given like reference numerals throughout the specification.

In the following embodiments, terms such as "first", "second", etc. are used to distinguish one component element from another component element without limitation.

In the following embodiments, singular expressions include plural expressions unless the context clearly indicates otherwise.

In the following embodiments, terms such as "comprising" or "having" mean that the features or components described in the specification are present, and the possibility of adding one or more other features or components is not previously excluded.

In the following embodiments, when a portion of a film, a region, a constituent element, or the like is on or over another portion, not only a case of directly on another portion but also a case of interposing another film, a region, a constituent element, or the like therebetween is included.

In the drawings, the size of the constituent elements may be exaggerated or reduced for convenience of explanation. For example, since the size and thickness of each of the structures shown in the drawings are arbitrarily shown for convenience of explanation, the present invention is not necessarily limited to the drawings.

In the following embodiments, the x-axis, the y-axis, and the z-axis are not limited to three axes on an orthogonal coordinate system, and can be interpreted in a broad sense including these. For example, the x-axis, y-axis, and z-axis may be orthogonal to each other, but may refer to different directions that are not orthogonal to each other.

When the embodiments are implemented in other ways, the particular sequence of processes may be performed in a different manner than illustrated. For example, two processes described as being performed in succession may be executed substantially concurrently or the processes may be executed in the reverse order of the description.

Hereinafter, the present disclosure will be described in detail with reference to the accompanying drawings.

In order to raise the screen ratio to the limit, a front-end component such as a front-end camera, an illuminance sensor, a microphone, and a speaker is disposed in a partial region of a screen included in a smart phone (smart phone), a tablet, a smart television (smart TV), a smart monitor (smart monitor), a smart watch (smart watch), and the like. In order to arrange these front-facing components, an open space for exposing the corresponding components needs to be formed in the display panel 10. As shown in fig. 1, such an open space may be variously implemented as a circular punched hole (hole) TH1, a notch (notch) TH2, an Island notch (Island notch) TH3, a straight line (straight line) TH4, or the like according to designs. In fig. 1, an open space of several forms is shown, but the form of the open space is not limited to the illustrated form and may be designed in various forms.

Fig. 2 is a conceptual diagram illustrating the contents of the open space TH formed in the display panel 10.

In the present specification, the display panel 10 includes a display screenAn active area AA may have a cross-sectional structure including a substrate base 11, a driving element layer 12 formed on the substrate base 11, a display element layer 13 formed on the driving element layer 12, and a cover layer 14 covering the display element layer 13. Among them, the display panel 10 may be an organic light emitting display panel (organic light emitting display panel), an inorganic light emitting display panel (inorganic light emitting display panel), a quantum dot light emitting display panel (quantum dot light emitting display panel), a liquid crystal display panel (Liquid crystal display panel), or a light emitting diode display panel (Light emitting diode display panel), etc., according to the type of display element, but is not limited to the listed types. On the other hand, the substrate base 11 may be composed of SiO-containing material ₂ The glass material as a main component is not limited thereto, and may be made of metal, plastic (e.g., polyimide), or a combination thereof.

The open space TH is used to expose front components such as a front camera, an illuminance sensor, a microphone, and a speaker disposed at the lower portion of the display panel 10. The open space TH may be formed to penetrate the entire display panel 10 in the thickness direction of the display panel 10. That is, the open space TH may be represented as a through hole, a via hole (via), an opening, or the like. The open space TH may be formed in a non-contact manner, and according to an embodiment of the present invention, the open space may be formed by a laser processing method using a laser processing system described later.

Hereinafter, for convenience of explanation, a laser processing method capable of minimizing damage (damage) of the display panel 10 by the embodiment of the present invention will be described with reference to the content of the open space TH in the form of the circular punched hole TH1 shown in fig. 1 (a). Before this, a laser processing system for performing laser processing will be described before explaining a laser processing method. [26] Fig. 3 is a diagram illustrating a laser processing system 100 according to an embodiment of the present invention.

The laser processing system 100 according to an embodiment of the present invention may be utilized for various laser processing such as laser cutting, laser drilling, laser writing (laser writing), laser patterning (laser patterning), laser scribing (laser scribing), and the like. Hereinafter, however, for convenience of explanation, the laser processing system 100 will be explained as being utilized for laser cutting processing.

Referring to fig. 3, the laser oscillator 110 may include a laser source capable of generating and outputting a laser beam of a specific wavelength. The type of the laser beam output from the laser oscillator 110 is not particularly limited and may be appropriately selected according to the type of the object W to be processed or the processing manner. For example, the laser beam output from the laser oscillator 110 may be any one of the following laser beams: solid laser beams including a ruby laser beam, a Nd: YAG laser beam, a Ti: sapphire laser beam, and the like; a liquid laser beam including a pigment laser beam and the like; comprising CO ₂ A gas laser beam such as a laser beam, a He-Ne laser beam, an Ar+ laser beam, an excimer laser beam, etc.; or an Ultraviolet (UV) laser beam. The laser oscillator 110 is connected to the controller 150. Characteristics of the laser beam output from the laser oscillator 110, such as output power, intensity, period, output timing (timing), etc., of the laser beam may be controlled by a signal generated by the controller 150.

The processing stage 130 may be configured to face the direction of laser irradiation. The processing table 130 has a seating surface on which the workpiece W is seated, and is movable in a preset direction in a state in which the workpiece W is seated. For example, the processing table 130 may be movable in each direction of the X-axis, the Y-axis, and the Z-axis, and may be rotatable about the Z-axis. The operation of the processing table 130, for example, the operation of the fixing member for fixing the workpiece W, or the moving speed or rotational speed, moving direction, moving distance, etc. of the processing table 130 may be controlled by the controller 150.

The mirror 121 may control the optical path of the laser beam La output from the laser oscillator 110. The number of mirrors 121 included in the laser processing system 100 is not particularly limited, and the mirrors 121 may be Galvano mirrors (Galvano-mirrors), and the mirrors may be connected to a Galvano scanner (Galvano-scanner). The action of the mirror 121, for example, the tilt angle (tilt angle) and the tilt speed (tilt speed) of the mirror 121, etc., may be controlled by the controller 150.

The lens 122 may be disposed between the processing stage 130 and the mirror 121. The lens 122 condenses the laser beam Lb reflected from the mirror 121, and irradiates the laser beam L to the workpiece W. In one embodiment of the invention, lens 122 includes an optical system capable of converging a laser beam, such as an f-theta lens, a Focusing (Focusing) lens, an Objective lens, a diffractive optical element (Diffraction Optical Elements, DOE), and the like. In the drawings, the lens 122 is shown as one, but is not limited thereto. For example, the lens 122 may be constituted by a plurality of spherical lenses or planar lenses.

The mirror 121 and the lens 122 may constitute the optical unit 120. The optical unit 120 can irradiate the laser beam L to a desired position on the workpiece W by adjusting the optical path of the laser beam La output from the laser oscillator 110. Further, the action and position of the optical unit 120 may be controlled by the controller 150.

Hereinafter, a laser processing method will be described, which uses such a laser processing system 100 to minimize damage (damage) of a display panel and to improve reliability and stability of a final product.

Fig. 4 to 10 illustrate a laser processing method according to an embodiment of the present invention. Among the steps in the drawing, the drawing on the left side is a plan view showing the processing surface PA of the object to be processed (or the opposite surface of the processing surface in the case of some steps of fig. 10), and the drawing on the right side is a sectional view showing a section cut along the section C-C' of the plan view.

The embodiment of fig. 4 to 10 is characterized in that laser processing is performed by sequentially irradiating laser light in steps at the time of laser processing, by which damage of the effective area AA due to the laser light is prevented.

The embodiments of fig. 4-10 may each include: a step of preparing a workpiece W having a machining surface PA on one surface thereof; a step of oscillating the laser by operating the laser oscillator 110 and selecting a processing position by the optical unit 120; a first processing step of irradiating a first laser beam along a first path on a processing surface PA of the workpiece W; a second processing step of irradiating a second laser beam along a second path on the processing surface PA of the workpiece W; and a step of forming an open space TH in the workpiece W by removing the dummy formed after the laser processing.

The workpiece W may be the display panel 10. Therefore, the workpiece W may have a cross-sectional structure in which a plurality of films are laminated. However, the workpiece W is not limited thereto, and may be glass (glass).

The workpiece W has a processing surface PA on one surface to be irradiated with a laser beam. The processing surface PA includes a sample area SA included in the final product, a dummy area DM not included in the final product, and a processing area TA corresponding to a boundary between the sample area SA and the dummy area DM.

The sample area SA may be the effective area AA of the display screen or a part of the display area, or may be a part of a boundary area (board area) included in the final product even if the screen is not displayed.

The dummy area DM is a portion removed by laser processing and corresponds to the open space TH of the display panel 10 after laser processing.

The processing region TA may be a portion to which an ablation (ablation) laser beam is irradiated in order to remove the dummy region DM. The laser processing system 100 performs laser processing based on processing coordinates, and in this case, the processing region TA is a region corresponding to the processing coordinates to which an ablation (ablation) laser beam is irradiated, and may be a line to cut.

How the embodiments uniquely perform laser processing in each processing step will be mainly described below with reference to the accompanying drawings.

In the first processing step of fig. 4 (a), the first laser light L41 is irradiated along the first path R41 on the virtual area DM of the processing surface PA of the object to be processed and a first pattern including a plurality of first holes H41 is formed corresponding to the first path R41. The processing surface PA is a laser irradiated surface, and may be a surface corresponding to an outer surface of the cover layer 14 of the display panel 10 in this embodiment.

The output power of the first laser beam L41 is smaller than that of the second laser beam L42 described later, and the spot size (spot size) of the laser beam irradiated to the processing surface is also small. Therefore, the width of the first hole H41 formed by the first laser light L41 is smaller than the width of the second hole H42 described later. The first hole H41 is formed to pass through a cross section of the work or a considerable number of films of the work formed by a plurality of laminated films.

The first path R41 is a portion on the virtual area DM adjacent to the machining area TA, and may be implemented in a form such as a straight line, an open curve, or a closed curve corresponding to the machining area TA. According to an embodiment, the first path R41 may be a path that is disposed adjacent to the processing area TA and formed in a form corresponding to the processing area TA. Accordingly, the first path R41 shown in fig. 4 may be a circular path formed on the virtual area DM corresponding to the circular processing area TA.

Wherein the first pattern is a set of processing points where the first laser light L41 is irradiated corresponding to the first path R41. Wherein the first hole H41 is an embodiment of a machining point. In the present specification, the processing point where the laser is irradiated is shown by a point, but this is shown exaggerated for convenience of description only, and the present invention is not limited thereto, and the first pattern may be formed in a line shape by very closely forming the plurality of first holes H41.

In the second processing step of fig. 4 (b), the second laser light L42 is irradiated along the second path R42 on the processing area TA of the processing surface of the object to be processed, and a second pattern including a plurality of second holes H42 is formed corresponding to the second path R42.

The output power of the second laser beam L42 is larger than that of the first laser beam L41, and the spot size irradiated to the processing surface is also large. Therefore, the width of the second hole H42 formed by the second laser light L42 is larger than the width of the first hole H41. The second hole H42 is formed to have a cross section that completely penetrates the workpiece.

The second path R42 is a portion on the machining area TA, and may be implemented in a form such as a straight line, an open curve, or a closed curve corresponding to the machining area TA. According to an embodiment, the second path R42 may be a path that is disposed on the processing area TA and is formed in the same shape as the processing area TA. Thus, the second path R42 shown in fig. 4 may be the same circular path as the circular processing area TA.

Wherein the second pattern is a set of processing points corresponding to the second path R42 to which the second laser light L42 is irradiated. Wherein the second hole H42 is an embodiment of a machining point. In the present specification, the processing point irradiated with the laser light is represented by a point, but this is shown exaggerated for convenience of description only, and the present invention is not limited thereto, and the second pattern may be formed in a line shape on the processing surface by a plurality of second holes H42 being formed very closely.

According to an embodiment of the present invention, in the second processing step, the shock wave and the large amount of gas (gas) generated due to the irradiation of the second laser light L42 are discharged through the first pattern formed in the first processing step. Therefore, according to an embodiment of the present invention, the laser damage (damage) of the effective area AA can be prevented as compared with the case where the second processing step is directly performed without performing the first processing step. Also, as for the first pattern, it is formed in the dummy area DM, disappears together when the dummy is removed, and since it is not included in the final product, the problem in the process is solved, and the defective rate of the final product is not affected at all. Since laser ablation (displacement) is necessary to form a punched hole in the second processing step, the intensity, output power, and spot size of the second laser light L42 should be determined according to the thickness or material of the object to be processed in order to remove the dummy object from the object to be processed. However, in the first processing step, since formation of micro holes in the object to be processed is sufficient to discharge the shock wave of the second laser light L42 or the gas generated in the process, the intensity or output power of the first laser light L41 is smaller than that of the second laser light L42, which is economically and technically advantageous.

In fig. 4 (c), when the second processing step is completed, it is confirmed that laser ablation (ablation) is performed in the processing area TA of the workpiece and that micro holes are formed in the virtual area DM.

In fig. 4 (d), when all the laser processing steps are completed, the dummy area DM is separated from the sample area SA, and becomes an Island-like dummy. The dummy object may be separated and removed from the display panel 10 by natural separation or physical impact. After the dummy is removed, a circular punched hole is formed in the display panel 10 as the open space TH.

Fig. 5 to 8 illustrate a laser processing method according to another embodiment of the present invention.

In each of the embodiments, the types of the plurality of films included in the processed object may be different from each other, and among the films included in the display panels of fig. 5 to 8, the films having the same reference numerals as those included in the display panels of fig. 1 to 4 may be the same type of film, the thickness of which may be different according to the implementation, and thus may have various expressions, not limited to that shown in the drawings. On the other hand, fig. 5 to 8 illustrate the steps of the laser processing method by simultaneously showing a cross-sectional view of the display panel and a plan view as seen from the processing surface.

First, referring to fig. 5, a laser processing method according to the embodiment of fig. 5 will be described.

In fig. 5 (a), the cross-sectional structure of the work may include a substrate base 11, a driving element layer 12 formed on the substrate base 11, a display element layer 13 formed on the driving element layer 12, and a cover layer 14 covering the display element layer 13. Wherein the cover layer 14 may be a thin film package (Thin Film Encapsulation).

In the first processing step of fig. 5 (b), the first laser beam L51 is irradiated along the first path R51 on the processing region TA of the processing surface PA of the object to be processed, and a first pattern including a plurality of films of the object to be processed is formed, with a part of the concave portion G51 selectively removed. The processing surface PA is a laser irradiated surface, and in this embodiment may be a surface corresponding to an outer surface of the cover layer 14 of the display panel.

The first laser beam L51 may be a UV laser beam, the output power of the first laser beam L51 is smaller than the output power of a second laser beam L52 described later, and a part of the film near the processing surface is selectively removed from among the plurality of films of the object to be processed. According to an embodiment, the first laser light L51 may remove only the cover layer 14 of the work object, or may remove a part or all of the display element layer 13 together when the cover layer 14 is removed. And the first laser light L51 may be a plurality of laser beams or may be implemented by irradiating the laser beams a plurality of times. Therefore, the width of the concave portion G51 formed by the first laser light L51 is larger than the width of the processing hole H52 included in the second pattern described later.

Wherein the first path R51 is a portion on the machining area TA, and may be implemented in a form such as a straight line, an open curve, or a closed curve corresponding to the machining area. According to an embodiment, the first path R51 may be a path that is disposed on the processing area TA and formed in the same shape as the processing area TA. Thus, the first path R51 shown in fig. 5 may be the same circular path as the circular processing area TA.

Wherein the first pattern is a set of processing points that irradiate the first laser light L51 corresponding to the first path R51. The concave portion G51 is an example of a processing point. According to the present embodiment, the first laser light L51 selectively removes a part of the film of the object to be processed, and thus the processing point can be realized as a concave shape instead of a through hole. In fig. 5, it is shown that laser processing is continuously performed such that a plurality of concave portions G51 are connected to each other, so that a first pattern is formed in a ring (donut) shape, which is exaggeratedly shown for convenience of explanation, and the present invention is not limited thereto, and the first pattern may be formed in a form of a plurality of point connections.

In the second processing step of fig. 5 (c), the second laser light L52 is irradiated along the same second path R52 as the first path R51 on the processing area TA of the processing surface PA of the object to be processed, and a second pattern including a plurality of processing holes H52 is formed corresponding to the second path R52. The processing surface is a laser irradiated surface, and in this embodiment, may be a surface which is processed in the first processing step and from which a part of the film is removed by the first laser light L51.

The second laser beam L52 may be a UV laser beam, and the output power of the second laser beam L52 is larger than that of the first laser beam L51, and the processing hole H52 is formed so as to penetrate the cross section of the object by removing the remaining film of the object that is not removed by the first laser beam L51.

Wherein the second pattern is a set of processing points corresponding to the second path R52 to which the second laser light L52 is irradiated. Wherein the machining hole H52 is an example of a machining point. In fig. 5, it is shown that laser processing is continuously performed for a short time so that a plurality of processing holes H52 are connected to each other, and thus the second pattern is formed in a form of a circular line, which is exaggeratedly shown for convenience of explanation, and the present invention is not limited thereto, and the first pattern may be formed in a form of a plurality of point connections.

According to an embodiment of the present invention, in the second processing step, a phenomenon in which a part of the laminated film of the object to be processed is tilted by the impact caused by the irradiation of the second laser light L52 occurs. In particular, when the work includes a thin and Flexible (Flexible) substrate 11 and the display element layer 13 of the work includes an organic light emitting element (OLED), warpage occurs between the display element layer 13 and the cover layer 14 due to an impact caused by laser light, and a defect of the effective area AA occurs due to such warpage. However, according to an embodiment of the present invention, in the first processing step, a part of the film that is liable to be lifted is selectively removed first, and in the second processing step, the laser light is irradiated to the portion from which a part of the film is removed to form the processing hole H52, and the output power of the first laser light L51 used in the first processing step is smaller than the output power of the second laser light L52 used in forming the processing hole H52, so that the lifting of the film due to the impact of the first laser light L51 can be minimized, and finally, the defect due to the lifting of the film in the final product can be minimized. When the second processing step is completed, it is confirmed that there is only minimal or no film lift around the periphery of the processing hole.

In fig. 5 (d), when all the laser processing steps are completed, the dummy region is separated from the sample region, and an Island-like dummy is formed. The dummy object may be removed from the display panel 10 by natural separation or physical impact. After the dummy is removed, a circular punched hole is formed in the display panel 10 as the open space TH.

In the laser processing method according to the embodiment of fig. 6, referring to fig. 6 (a), the object to be processed further includes a first protective layer 15 on the cover layer 14, compared to the embodiment of fig. 5. The first protective layer 15 may be a temporary film (Temporary Protection film).

Unlike the embodiment of fig. 5, in the first processing step of the embodiment of fig. 6, the first laser light L51a may remove a part or all of the first protective layer 15, the cover layer 14, and the display element layer 13 of the processed object. In detail, in the first processing step of fig. 6 (b), the first laser light L51 is irradiated along the first path R51 on the processing region TA of the processing surface PA of the object to be processed, and the first pattern including the concave portion G51a from which all or part of the first protective layer 15, the cover layer 14, and the display element layer 13 are removed from the plurality of films of the object to be processed is formed. Since other laser processing methods are the same as those described with respect to fig. 5, duplicate description will be omitted.

In the laser processing method according to the embodiment of fig. 7, referring to (a) of fig. 7, the object to be processed may further include a first protective layer 15 on the cover layer 14 and a second protective layer 16 on the first protective layer, compared to the embodiment of fig. 5. The second protective layer 16 may be an acid-resistant film (Anti-acid Protection Film), among others.

Unlike the embodiment of fig. 5, in the first processing step of the embodiment of fig. 7, the first laser light L51 may remove a part or all of the second protective layer 16, the first protective layer 15, the cover layer 14, and the display element layer 13 of the processed object. In detail, in the first processing step of fig. 7 (b), the first laser light L51 is irradiated along the first path R51 on the processing region TA of the processing surface PA of the object to be processed, and the first pattern including the concave portion G51b of all or part of the second protective layer 16, the first protective layer 15, the cover layer 14, and the display element layer 13 is removed from the plurality of films of the object to be processed is formed. Wherein the first laser light L51 may be a UV laser beam.

In the second processing step of fig. 7 (c), the second laser beam L52 is irradiated along the second path R52 on the processing region TA of the processing surface PA of the object to be processed, thereby forming a second pattern including a filament (filtration) formed along the thickness direction of the object to be processed. Wherein the second laser light L52 may be a different type of laser light from the first laser light. For example, the second laser light L52 may be a Bessel beam (Bessel beam), and since the Bessel beam changes the microstructure of the cross section of the workpiece, a wire or film connecting a plurality of micro grooves along the thickness direction of the workpiece may be formed to separate the interface. [73] In fig. 7 (d), when all the laser processing steps are completed, the interface between the dummy region and the sample region is separated by the filament. The dummy may be removed from the display panel 10 through a chemical or physical etching (etching) process. After the dummy is removed, a circular punched hole is formed in the display panel 10 as the open space TH. Since other detailed laser processing methods are the same as those described with respect to fig. 5, duplicate description will be omitted.

In comparison with the embodiment of fig. 5, in the laser processing method according to the embodiment of fig. 8, the processed object further includes the first protective layer 15 on the cover layer 14. Unlike the embodiment of fig. 5, the embodiment of fig. 8 may form a first pattern including first processing holes H51c for peeling (localization) a portion of the first protective layer 15 of the processed object by the first laser light L51a in the first processing step.

In fig. 8 (a), the cross-sectional structure of the work may include a substrate base plate 11, a driving element layer 12 formed on the substrate base plate 11, a display element layer 13 formed on the driving element layer 12, a cover layer 14 covering the display element layer 13, and a first protective layer 15 for containing the cover layer 14. Wherein the cover layer 14 may be a thin film package (Thin Film Encapsulation), and the first protective layer 15 may be a temporary protective film (Temporary Protection film).

In the first processing step of fig. 8 (b), the first laser light L51 is irradiated along the first path R5 on the sample region SA of the processing surface PA of the object to be processed, forming a first pattern including the first processing holes H51c of the plurality of films of the object to be processed from which the first protective layer 15 is removed. The processing surface PA is a laser irradiated surface, and in this embodiment may be a surface corresponding to an outer surface of the first protective layer 15 of the display panel.

The first laser light L51 may be a laser beam of a different type from the second laser light L52 described later. As an example, the first laser L51 may be CO ₂ The laser beam, the second laser L52 may be a UV laser beam. Due to the first laserThe power of L51 is larger than that of the second laser light L52, and therefore the first protective layer 15 of the work can be removed by irradiating the laser light once. If an attempt is made to remove the first protective layer 15 of the workpiece by the second laser light L52, the output is weaker than that of the first laser light L51, and therefore, it is necessary to irradiate the laser light a plurality of times. Therefore, the removal of the first protective layer 15 using the first laser light L51 is advantageous in terms of the process.

The first path R51 is a portion on the sample area SA in the vicinity of the processing area TA, and may be implemented in a form such as a straight line, an open curve, or a closed curve corresponding to the processing area. According to an embodiment, the first path R51 may be a path that is disposed on the sample area SA and formed in the same shape as the processing area TA. Thus, the first path R51 shown in fig. 8 may be the same circular path as the circular processing area TA.

Wherein the first pattern is a set of processing points that irradiate the first laser light L51 corresponding to the first path R51. The first machining hole H51c is an example of a machining point. In fig. 8, it is shown that laser processing is continuously performed such that a plurality of first processing holes H51c are connected to each other, so that a first pattern is formed in a circular line, which is exaggeratedly shown for convenience of explanation, and the present invention is not limited thereto, and the first pattern may be formed of a plurality of connected points.

In fig. 8 (c), when the first processing step is completed, the inner region of the first path R51 is formed in an Island shape and separated from the sample region SA outside the first path R51. The rear region of the first path R51 is a peeling portion 15c that can be removed from the display panel 10. For example, the peeling portion 15c may be peeled from the display panel 10 by attaching an adhesive member to the upper surface and lifting up. When the peeled portion 15c is removed, the first protective layer 15 of the work is selectively removed, and the recess G51c of the open cover layer 14 is formed. The concave portion G51c may have a cylindrical shape having the first path R51 as a circumference and the thickness of the first protective layer 15 as a height, but the present invention is not limited thereto and may have various forms according to the form formed in the open space of the display panel.

In the second processing step of fig. 8 (d), the second laser light L52 is irradiated along the second path R52 on the processing area TA of the processing surface PA of the object to be processed, and a second pattern including a plurality of second processing holes H52 is formed corresponding to the second path R52. The processing surface is a laser irradiated surface, and in this embodiment, the processing may be performed in a first processing step and the covering layer 14 of the first protective layer 15 is removed by the first laser light L51.

The second path R52 is a portion on the machining area TA, and may be implemented in a form such as a straight line, an open curve, or a closed curve corresponding to the machining area. According to an embodiment, the second path R52 may be a path that is disposed on the processing area TA and formed in the same shape as the processing area TA. Thus, the second path R52 shown in fig. 8 may be the same circular path as the circular processing area TA. At this time, the radius of the second path R52 may be smaller than the radius of the first path R51.

The second laser beam L52 is different from the first laser beam L51 in type and output power is small, and the second processing hole H52 is formed by removing the remaining film of the object to be processed which is not removed by the first laser beam L51, and the second processing hole H52 penetrates the cross section of the object to be processed.

Wherein the second pattern is a set of processing points corresponding to the second path R52 to which the second laser light L52 is irradiated. Wherein the second tooling hole H52 is an example of a tooling point. In fig. 8, it is shown that the laser processing is continuously performed such that a plurality of second processing holes H52 are connected to each other, so that the second pattern is formed in the form of a circular line, which is exaggeratedly shown for convenience of explanation, and the present invention is not limited thereto, and the second pattern may be formed of a plurality of connected points.

According to an embodiment of the present invention, a portion of the film that is liable to be tilted is first selectively removed in the first processing step, so that the film tilt caused by the laser beam irradiation can be minimized, and as a result, defects caused by the film tilt in the final product can be prevented.

In fig. 8 (e), when all the laser processing steps are completed, the dummy region is separated from the sample region, and becomes an Island-like dummy. The dummy object may be removed from the display panel 10 by natural separation or physical impact. After the dummy is removed, a circular punched hole is formed in the display panel 10 as the open space TH.

In the first processing step of fig. 9 (a), the first laser light L61 is irradiated along the first path R61 on the sample region SA of the processing surface PA of the object to be processed, and a first pattern including a plurality of first lines connecting a plurality of fine grooves along the thickness of the object to be processed is formed corresponding to the first path R61. The processing surface is a laser irradiated surface, and in this embodiment may be a surface corresponding to the outer surface of the cover layer 14 of the display panel 10.

The first laser beam L61 is a beam different from a second laser beam L62 concept (concept) described later. Unlike the second laser beam L62 for forming the through hole by ablation (ablation), the first laser beam L61 is an interference beam, and a line connecting a plurality of fine grooves in the thickness direction of the workpiece is formed at the irradiated portion. According to an embodiment, the first laser light L61 may be a Bessel beam (Bessel beam), and the Bessel beam is formed by interference and deforms the cross section of the work to be elongated and uniform, so that a line or film in which the fine grooves are connected in the thickness direction of the work is observed. The first laser light L61 may be implemented by an optical unit different from the second laser light L62.

The first path R61 is a portion on the sample area SA adjacent to the processing area TA, and may be implemented in a form such as a straight line, an open curve, or a closed curve corresponding to the processing area TA. According to an embodiment, the first path R61 may be a path that is disposed adjacent to the processing area TA and that corresponds to the morphological formation of the processing area TA. Accordingly, the first path R61 shown in fig. 9 may be a circular path formed on the sample area SA corresponding to the circular processing area TA.

Wherein the first pattern is a set of processing points that irradiate the first laser light L61 corresponding to the first path R61. Wherein the first line on the cross section of the object to be processed is an example of a processing point. In the present specification, the processing point to which the laser is irradiated is indicated by a point, but it is exaggeratedly indicated for convenience of explanation, and the present invention is not limited thereto, and the plurality of first lines are formed very closely so that the first pattern may be formed in a line shape on the processing surface PA.

In the second processing step of fig. 9 (b), the second laser light L62 is irradiated along the second path R62 on the processing area TA of the processing surface PA of the object to be processed, and a second pattern including a plurality of second holes H62 is formed corresponding to the second path R62.

The output power of the second laser beam L62 is larger than that of the first laser beam L61, and is a laser beam used for ablation (ablation) processing. Therefore, the second hole H62 formed by the second laser beam L62 is formed so as to penetrate the cross section of the workpiece by removing the processing point of the workpiece.

The second path R62 is a portion on the machining area TA, and may be implemented in a form such as a straight line, an open curve, or a closed curve corresponding to the machining area TA. According to an embodiment, the second path R62 may be a path that is disposed on the processing area TA and formed in the same shape as the processing area TA. Thus, the second path R62 shown in fig. 9 may be the same circular path as the circular processing area TA.

Wherein the second pattern is a set of processing points corresponding to the second path R62 to which the second laser light L62 is irradiated. Wherein the second hole H62 is an example of a machining point. In the present specification, the processing point irradiated with the laser light is represented by a point, but is exaggeratedly represented for convenience of explanation, the present invention is not limited thereto, and the plurality of second holes H62 are formed very closely so that the second pattern may be displayed in a line shape on the processing surface PA.

According to an embodiment of the present invention, in the second processing step, the micro-cracks generated by the irradiation of the second laser light L62 cannot proceed due to the first pattern including the plurality of first lines formed in the first processing step. Thus, according to an embodiment of the present invention, it is possible to prevent cracks from penetrating into the sample SA region, compared with the case where the second processing step is directly performed without performing the first processing step. The first pattern is formed in the sample area SA, but the first pattern is formed by an interference beam, and is in the form of a broken line connected along a cross section of the workpiece, for example, instead of a through hole, so that the quality of the sample area SA is not affected in the final product. However, the first pattern may be observed in the final product by a microscope or the like. In the first processing step, a protective film that prevents impact and damage caused by laser ablation (displacement) is formed in advance, thereby having the effect of preventing damage to the sample area SA during the formation of the punched hole, and also not affecting the quality of the final product.

On the other hand, the present embodiment can be effectively applied to forming an open space even when the object to be processed is glass (glass), except for the case where the object to be processed is the display panel 10.

In fig. 9 (c), it was confirmed that when the second processing step was completed, laser ablation (ablation) was performed in the processing region TA of the workpiece, and a fine line or film was formed in the thickness direction of the workpiece in the sample region SA by the interference beam.

In fig. 9 (d), when all the laser processing steps are completed, the dummy region is separated from the sample region, and an Island-like dummy is formed. The dummy object may be separated and removed from the display panel by physical impact. After the dummy is removed, a circular punched hole is formed in the display panel 10 as the open space TH.

In the first processing step of fig. 10 (a), a first laser beam L71 is irradiated along a first path R71 on a processing region TA of a processing surface PA of a workpiece, and a first pattern including a filament (filtration) formed along a thickness direction of the workpiece is formed corresponding to the first path R71. The processing surface PA is a surface irradiated with laser light, and may be a surface corresponding to the cover layer 14 of the display panel 10 in this embodiment.

The first laser beam L71 is a beam conceptually different from the second laser beam L72 described later. Unlike the second laser beam L72 for forming the through hole by ablation (ablation), the first laser beam L71 is a Bessel beam (Bessel beam) and forms a wire portion (filtration) formed by connecting a plurality of fine grooves having a size of 1 μm or less along the thickness direction of the workpiece at the irradiation portion. According to an embodiment, the first laser light L71 may be a bessel beam, and since the bessel beam deforms the microstructure of the cross section of the object to be processed, a thread-like portion (filtration) which is a line or film connecting a plurality of micro grooves along the thickness direction of the object to be processed may be observed.

The first laser light L71 may be implemented by an optical unit different from the second laser light L72.

The first path R71 is a portion on the machining area TA, and may be implemented in a form such as a straight line, an open curve, or a closed curve corresponding to the machining area TA. According to an embodiment, the first path R71 may be a path which is disposed on the processing area TA and corresponds to a morphological formation of the processing area TA. Accordingly, the first path R71 shown in fig. 10 may be a circular path formed on the machining area TA corresponding to the circular machining area TA.

Wherein the first pattern is a set of processing points where the first laser light L71 is irradiated corresponding to the first path R71. The wire-like portion (filtration) on the cross section of the workpiece is an example of a processing point. In the present specification, the machining point where the laser is irradiated is indicated by a dot, but for convenience of explanation, the present invention is not limited thereto, and a plurality of filiform portions (filatures) are formed very closely so that the first pattern may be displayed in a line shape on the machining surface PA.

In the second processing step of fig. 10 (b), the second laser light L72 is irradiated to the second position on the virtual area DM of the opposite surface of the processing surface PA described in the first processing step of the object to be processed, and the second laser light L72 irradiated to the second position of fig. 10 (c) melts the object to be processed in the second position by applying heat. The opposite surface of the processed surface PA corresponds to the surface corresponding to the substrate 11 of the display panel.

The second laser beam L72 is a laser beam for applying heat to the workpiece, and is a laser beam having excellent heat absorption of a material as compared with the ablation (ablation) laser beam of the other embodiment. Such a second laser can melt and mold the substrate base plate 11 made of glass (glass).

Wherein the second location is a point on the virtual area DM. However, the present invention is not limited thereto, and the second position may be a plurality of points on the virtual area DM, a point moving in the virtual area DM, a plane of a predetermined width on the virtual area DM, or a line of a predetermined length, instead of a single point. As shown in the drawing, the second position may be a center position of the circular processing area TA, but is not limited thereto, and preferably may be a position capable of effectively applying heat to an area from the virtual area DM to the processing area TA.

In fig. 10 (c), the dummy area DM is separated along the filament (filament) interface formed in the first processing step as the molding proceeds with the thermoforming. On the other hand, since the filiform portion (filtration) is formed along the first path on the processing area TA, the crack does not propagate to the sample area SA, and thus the problem of damage caused by the crack does not occur.

In fig. 10 (d), when all the laser processing steps are completed, the dummy area DM is separated from the sample area SA, and becomes an Island-like dummy. The dummy is separated and removed from the display panel 10 due to physical impact caused by direct contact or indirect contact such as air (air). After the dummy is removed, a circular punched hole is formed in the display panel 10 as the open space TH.

According to an embodiment of the present invention, it is possible to solve the problem of crack propagation at the time of thermal damage due to laser light or virtual object removal by the sample area SA generated in the process of directly irradiating an ablation (ablation) laser along the processing area TA on the processing surface PA and separating and removing the virtual area DM. Specifically, in the first processing step, a filament (filament) is formed in the thickness direction of the object to be processed in the processing region TA on the processing surface PA, and in the second processing step, not an ablation (absorption) laser is irradiated to the processing region, but a laser for heating the virtual region is irradiated, so that the virtual object is easily separated from the display panel 10 by a combination of the shaping of the virtual region DM and the filament (filament). And according to the present embodiment, there is an advantage in that, unlike other modes, since a taper (taper) is not formed, it is possible to prevent the periphery of the open space TH from becoming a bezel (bezel), and it is possible to increase the screen ratio as compared with the display panel 10 in which the open space TH is formed in a taper (taper).

Fig. 11 and 13 illustrate a laser processing method according to still another embodiment of the present invention. Among the steps in the drawing, the drawing on the left side is a plan view showing the processing surface of the object to be processed, and the drawing on the right side is a sectional view showing a section cut along the C-C' portion of the plan view. In each step in the drawing, only one drawing is shown as a plan view showing the processing surface of the object to be processed.

In the embodiments of fig. 11 and 13, when the laser light is irradiated to the processing path TA at the time of laser processing, a time interval is set between the laser light irradiated last time and the laser light irradiated next time by various means, thereby having the effect of preventing the laser light from causing thermal damage to the effective area AA and improving the accuracy of processing.

The laser processing method according to another embodiment of the present invention includes: a step of preparing a workpiece W having a machining surface PA on one surface; a step of oscillating the laser by operating the laser oscillator 110 and selecting a processing position by the optical unit 120; continuously and repeatedly irradiating laser light to the processing region and a position different from each other on a virtual region adjacent to the processing region; and a step of forming an open space TH in the workpiece W by removing the dummy formed after the laser processing. Among them, the steps of continuously and repeatedly irradiating laser light are described in more detail as follows: a first step of irradiating a laser beam to a first position on the processing area TA at a first time; a second step of irradiating the laser light to a second location on the virtual area DM adjacent to the first location at a second time successive to the first time; a third step of irradiating the laser light to a third position on the processing area TA adjacent to the first position at a third time successive to the second time; and a fourth step of irradiating the laser light to a fourth location on the virtual area DM adjacent to the third location at a fourth time successive to the third time, the first to fourth steps may be repeatedly performed over the entire processing area.

The workpiece W may be the display panel 10. Therefore, the work W may have a cross-sectional structure in which a plurality of films are laminated on the substrate 11 made of glass (glass). The workpiece W includes a processing surface PA on one surface to be irradiated with a laser beam.

The processing surface PA includes a sample area SA included in the final product, a dummy area DM not included in the final product, and a processing area TA corresponding to a boundary between the sample area SA and the dummy area DM.

The sample area SA may be a part of the effective area AA of the display screen, or may be a part of a boundary area (board area) included in the final product even if the screen is not displayed.

The processing region TA may be a portion to which an ablation (ablation) laser beam is irradiated in order to remove the dummy region DM. In this case, the laser processing system 100 may be configured to perform laser processing based on processing coordinates, and the processing region TA may be a region corresponding to the processing coordinates to which an ablation (ablation) laser beam is irradiated.

The interval between the first time when the laser beam is first irradiated onto the processing area TA and the third time when the laser beam is again irradiated onto the processing area TA may be different depending on the type or thickness of the workpiece W, the size and shape of the open space to be processed, and the like. The interval between the first time and the third time may be: when the laser processing is performed at a position adjacent to the processing region TA, the laser processing performed at the third time is not affected (thermally damaged) by the heat generated by the laser processing performed at the first time. Wherein, the time may represent a specific time or point of time when the laser light is irradiated.

With reference to fig. 11, a step of initially irradiating the workpiece with laser light to a step of removing the dummy object will be described in detail.

In fig. 11 (a), at a first time, a laser beam L80 is irradiated to a first position on a processing area TA of a processing surface PA of a workpiece to form a first hole H81. The processing surface PA is a surface irradiated with laser light, and may be a surface corresponding to the cover layer 14 of the display panel 10 in this embodiment.

Wherein the first time may be any time.

The laser beam L80 is an ablation (ablation) laser beam, and has an output, a spot size, an intensity, and the like, which can penetrate a cross section of a workpiece, according to the thickness or material of the workpiece.

Wherein the first position corresponds to a machining point on the machining PA surface on the machining area TA.

In fig. 11 (b), at a second time subsequent to the first time, laser light L80 is irradiated to a second position near the first position on the virtual area DM of the processing surface PA of the object to be processed to form a second hole H82.

Wherein the second position corresponds to a machining point of the machining surface PA on the virtual area DM. The second location may be a location on the virtual area DM that is close to the first location, characterized in that the distance between the first location and the second location is 1/10 to 1/20 times the thickness of the object to be processed. If the distance between the first position and the second position is greater than 1/10 of the thickness of the object to be processed, the dummy area DM cannot be separated by laser processing. If the distance between the first position and the second position is less than 1/20 times the thickness of the object to be processed, there is no difference from the general laser processing method, and there is a problem in that the laser processing causes thermal damage to the sample area SA.

When the machining area TA is a circular punched hole, the second position may be a point on the outer peripheral surface of the first concentric circle TA1 smaller than the radius of the machining area TA as a concentric circle (concentric circle) concentric with the machining area TA.

Wherein the second time may be a next time subsequent to the first time.

In fig. 11 (c), at a third time subsequent to the second time, laser light L80 is irradiated to a third position close to the second position on the virtual area DM of the processing surface PA of the object to be processed to form a third hole H83.

Wherein the third position corresponds to a machining point of the machining surface PA on the virtual area DM. The third position may be a position on the virtual area DM near the second position, characterized in that a distance between the second position and the third position is 1/10 to 1/20 times a thickness of the object to be processed. When the machining area TA is a circular punched hole, the third position may be a point on the outer peripheral surface of the second concentric circle TA2 having a smaller radius than the machining area TA and smaller radius than the first concentric circle as a concentric circle concentric with the machining area TA.

Wherein the third time may be a next time subsequent to the second time.

In fig. 11 (d), at a fourth time subsequent to the third time, laser light L80 is irradiated to a fourth position near the third position on the virtual area DM of the processing surface PA of the object to be processed to form a fourth hole H84.

Wherein the fourth position corresponds to a machining point of the machining surface PA on the virtual area DM. The fourth position is one point on the outer peripheral surface of the first concentric circle TA1 that is the same as the second position, and the distance from the fourth position to the second position may be equal to or greater than the distance from the fourth position to the third position. Since the fourth position is located on the outer peripheral surface of the first concentric circle TA1, it is possible to be located closer to the machining area TA than the third position located on the outer peripheral surface of the second concentric circle TA 2.

Wherein the fourth time may be a next time subsequent to the third time.

In fig. 11 (e), at a fifth time subsequent to the fourth time, laser light L80 is irradiated to a fifth position near the fourth position on the processing area TA of the processing surface PA of the processed object to form a fifth hole H85.

Wherein the fifth position corresponds to a machining point of the machining surface PA on the machining area TA. The fifth position is a point on the same machining area TA as the first position.

Wherein the fifth time may be a next time subsequent to the fourth time. The interval between the first time and the fifth time at which the laser light is initially irradiated to the processing region TA may be varied according to the type or thickness of the object to be processed, the size or shape of the open space TH to be processed, and the like. It has been confirmed that, when a punched hole having a diameter of 3.5mm is experimentally formed in the organic light emitting display panel, there is a minimum time interval of about 0.1 seconds between the first time at which the laser light L80 is initially irradiated to the processing region TA and the fifth time at which the laser light L80 is again irradiated to the processing region TA, which is the shortest time to prevent thermal damage due to the laser light.

In fig. 11 (f), the steps described in fig. 11 (a) to 11 (e) are sequentially repeated to sequentially repeat the formation of the plurality of holes by the laser processing on the circular processing region TA, the outer peripheral surface of the first concentric circle TA1, and the outer peripheral surface of the second concentric circle TA 2.

In fig. 11 (g), when all the laser processing steps are completed, the dummy area DM is separated from the sample area SA, and becomes an Island-like dummy. The dummy object may be separated and removed from the display panel 10 by natural separation or physical impact. After the dummy is removed, a circular punched hole is formed in the display panel 10 as the open space TH.

In order to solve the problem of thermal damage and spread of damage to a sample area, which are generally generated when laser light is continuously irradiated along a processing path on a processing area TA of an object to be processed to form a dummy object and removed, an embodiment according to the present invention is characterized in that a pause interval (pause) or a delay time (time delay) is set between a last processing point and a next processing point of the processing path on the processing area TA by expanding the processing path onto a dummy area DM. According to an embodiment of the present invention, instead of continuously irradiating laser light to a processing point adjacent to the processing area TA, irradiation of the next laser light is suspended for a prescribed time after the current laser irradiation, thereby having an effect of preventing thermal damage of the processing area by the laser light.

In fig. 11, since the laser light is irradiated twice to the virtual area DM from the first irradiation step to the processing area TA to the second irradiation step, the description is made of an embodiment of three concentric circles (TA, TA1, TA 2) including a circular processing area, but the present invention is not limited to this, and it is obvious that an embodiment of omitting one processing step and having two concentric circles including a circular processing area, or an embodiment of adding additional processing steps and having four or more concentric circles may be included.

In fig. 11, the laser processing is continued from the first position on the processing area TA to the second position and the third position on the virtual area DM, but the present invention is not limited to this, and it is obvious that the laser processing may be continued from the third position on the virtual area DM to the second position and the first position on the processing area TA.

Fig. 12 (a) is a punched picture according to a comparative example, in which a punched hole is formed in a work by continuously irradiating a circular processing region with laser light and then removing a dummy. At the edge of the punched hole formed with a radius of 2837.129 μm, laser-induced thermal damage occurred, and the width of the damaged portion where thermal damage was measured was about 284.25 μm on average. The width is a distance from the start point to the end point of a damaged portion where thermal damage occurs with respect to the center portion of the punched hole.

Fig. 12 (b) is a punched image processed by the laser processing method of fig. 11, in which laser light is sequentially and alternately irradiated on a path which is a virtual area concentric with a circular processing area, and then the virtual object is removed, whereby a punched hole is formed in the object to be processed. At the edge of the punched hole formed with a radius of 2835.348 μm, laser-induced thermal damage occurred, and the width of the damaged portion where thermal damage was measured was about 92.068 μm on average. The width of the damaged portion of fig. 12 (b) was confirmed to be 1/3 or less as compared with the width of the damaged portion of fig. 12 (a). In summary, when an open space is formed in a processed object by the laser processing method of fig. 12, thermal damage is small and damage due to laser light can be minimized compared to the method of the comparative example.

The laser processing method according to another embodiment of the present invention further includes: a step of preparing a workpiece W having a machining surface PA on one surface; a step of oscillating the laser by operating the laser oscillator 110 and selecting a processing position by the optical unit 120; a step of discontinuously and repeatedly irradiating the laser to different positions on the processing region; and a step of forming an open space TH in the workpiece W by removing the dummy formed after the laser processing. Wherein, the step of discontinuously and repeatedly irradiating laser is described in more detail, the step comprises: a first step of irradiating a laser beam to a first position on the processing area TA at a first time; a second step of suspending at a second time successive to the first time; a third step of irradiating the laser light to a third position on the processing area TA adjacent to the first position at a third time successive to the second time; and a fourth step of suspending at a fourth time successive to the third time, the first to fourth steps being repeatedly performed over the entire processing region.

The workpiece W may be the display panel 10. Therefore, the work W may have a cross-sectional structure in which a plurality of films are laminated on the substrate 11 made of plastic (for example, polyimide). The workpiece W includes a processing surface PA on one surface to be irradiated with a laser beam.

The processing region TA may be a portion to which an ablation (ablation) laser beam is irradiated in order to remove the dummy region DM. In this case, the laser processing system 100 may perform laser processing based on processing coordinates, and the processing area TA may be a line to be cut corresponding to the processing coordinates of the irradiation ablation (ablation) laser beam.

The interval between the first time when the laser beam is first irradiated onto the processing area TA and the third time when the laser beam is again irradiated onto the processing area TA may be different depending on the type or thickness of the workpiece W, the size and shape of the open space TH to be processed, and the like. The interval between the first time and the third time may be: when the laser processing is performed at a position adjacent to the processing region TA, the laser processing performed at the third time is not affected (e.g., thermally damaged) by the heat generated by the laser processing performed at the first time. According to an embodiment, the interval between the first time and the third time may be at least 0.1 seconds.

Referring to fig. 13, a step of initially irradiating the workpiece with laser light to a step of removing the dummy object will be described in detail.

In fig. 13 (a), at a first time, a laser beam L90 is irradiated to a first position on a processing area TA of a processing surface PA of a workpiece W to form a first hole H91. The processing surface is a surface irradiated with laser light, and in this embodiment may be a surface corresponding to a cover layer of a display panel.

Wherein the first time may be any time.

The laser beam is an ablation (ablation) laser beam, and has an output, a spot size, an intensity, and the like, which can penetrate a cross section of a workpiece, depending on the thickness or material of the workpiece.

Wherein the first position corresponds to a machining point of the machining surface PA on the machining area TA.

In fig. 13 (b), after the pause (pause) at a second time subsequent to the first time, laser light L90 is irradiated to a third position near the first position on the processing area TA of the processing surface of the object to be processed at a third time subsequent to the second time to form a third hole H93.

Wherein the second time may be a next time subsequent to the first time and the third time may be a next time subsequent to the second time. The interval between the first time and the third time may be at least about 0.1 seconds.

Wherein the third position corresponds to a machining point of the machining surface PA on the machining area TA, and may be adjacent to the first position.

In fig. 13 (c), after a fourth time pause (pause) subsequent to the third time, laser light is irradiated to a fifth position near the third position on the processing area TA of the processing surface PA of the object to be processed at a fifth time subsequent to the fourth time to form a fifth hole H95.

Wherein the fourth time may be a next time subsequent to the third time and the fifth time may be a next time subsequent to the fourth time. The interval between the third time and the fifth time may be at least about 0.1 seconds.

Wherein the fifth position corresponds to a machining point of the machining surface PA on the machining area TA, and may be immediately adjacent to the third position.

In fig. 13 (d), laser irradiation may be repeated in the same manner as the steps described in fig. 13 (a) to 13 (c), so that a plurality of holes generated by laser processing are sequentially formed on the circular processing region TA.

In fig. 13 (e), when all the laser processing steps are completed, the dummy area DM is separated from the sample area SA, and becomes an Island-like dummy. The dummy object may be separated and removed from the display panel 10 by natural separation or physical impact. After the dummy is removed, a circular punched hole is formed in the display panel 10 as the open space TH.

According to an embodiment of the present invention, in general, in order to solve the problem of heat damage and spread of damage to a sample area generated when a dummy is formed and removed by continuously irradiating laser light along a processing path on a processing area TA of an object to be processed, a pause interval (pause) or a delay time (time delay) is set between a last processing point and a next processing point of the processing path on the processing area TA. According to an embodiment of the present invention, instead of continuously irradiating laser light to a processing point adjacent to the processing area TA, irradiation of the next laser light after a prescribed time is suspended after the current laser irradiation, thereby having an effect of preventing thermal damage of the processing area TA by the laser light.

Fig. 14 is a photograph of a punched hole according to a comparative example and a punched hole processed according to the laser processing method of fig. 13.

Fig. 14 (a) is a punched picture according to a comparative example, in which a punched hole is formed in a work by continuously irradiating a circular processing region with laser light and then removing a dummy. At the edges of the resulting punched hole, laser induced thermal damage occurred, and the width of the damaged portion where thermal damage was measured was about 55.119 μm on average. The width is a distance from the start point to the end point of a damaged portion where thermal damage occurs with respect to the center portion of the punched hole.

Fig. 14 (b) is a punched hole picture processed by the laser processing method of fig. 13, in which laser light is irradiated to a first position on a circular processing region, then the laser processing is performed so that the laser light is irradiated to a position near the first position, and then a dummy is removed to form a punched hole on a workpiece. At the edges of the resulting punched hole, laser induced thermal damage occurred, and the width of the damaged portion where thermal damage was measured was about 29.525 μm on average. The width of the damaged portion of fig. 14 (b) was confirmed to be 1/2 or less as compared with the width of the damaged portion of fig. 14 (a). In summary, when an open space is formed in a processed object by the laser processing method of fig. 13, thermal damage is small and damage due to laser light can be minimized compared to the method of the comparative example.

On the other hand, in order to expose the front-facing components such as the front-facing camera, the illuminance sensor, the microphone, and the speaker disposed at the lower portion of the display panel, the open space TH formed so as to penetrate the thickness direction of the display panel is formed by the laser processing method described above, and in this case, the inner surface of the open space TH has a taper shape T. Here, the taper T is a shape formed to protrude into the open space TH as the thickness of the display panel becomes thinner from the processing surface PA to the opposite surface of the processing surface. Since such a taper T cannot be used as the effective area AA in the display panel, it is used as a bezel (bezel), and the wider the space used as a bezel, the smaller the picture scale, and thus the taper T needs to be reduced in the design to maximize the picture scale.

Hereinafter, a laser processing method of a display panel capable of minimizing a taper T according to an embodiment of the present invention will be described. A laser processing method capable of minimizing a taper T described later may be included as a post-processing process according to the embodiments of the laser processing method of fig. 4 to 9, 11, and 13 described above.

Fig. 15 (a) to 15 (c) may be the laser processing method of fig. 4 to 9, 11, and 13 described above, but for convenience of explanation, the explanation will be simplified conceptually.

In fig. 15 (a), a first laser beam L1 is irradiated to a processing region TA of a workpiece W.

The first laser beam L1 is an ablation (ablation) laser beam, and has an output power, a spot size, an intensity, and the like, which can penetrate a cross section of the workpiece W according to the thickness of the workpiece W or a material.

In fig. 15 (b), a hole H1 is formed in the processing region irradiated with the first laser light L1, and the sample region SA is separated from the dummy region DM by the hole H1.

The workpiece W may be the display panel 10. Therefore, the workpiece W may have a cross-sectional structure in which a plurality of films are laminated. However, the object to be processed is not limited thereto, and may be glass (glass). The workpiece W includes a sample area SA included in the final product, a virtual area DM not included in the final product, and a processing area TA corresponding to a boundary between the sample area SA and the virtual area DM.

The virtual area DM is a portion removed by laser processing and corresponds to the open space TH of the workpiece W after laser processing.

The processing region TA may be a portion to which an ablation (ablation) laser beam is irradiated in order to remove the dummy region DM. The laser processing system 100 performs laser processing based on processing coordinates, and in this case, the processing region may be a region corresponding to the processing coordinates of the irradiation ablation (ablation) laser beam, and may be a line to cut.

In fig. 15 (c), the virtual object is removed to form an open space TH in the workpiece. In this case, the inner surface of the open space TH has a taper T.

In fig. 15 (d), the second laser light L2 is irradiated to the taper region TPA corresponding to the taper T.

The second laser beam L2 is an ablation (ablation) laser beam, and has an output power, a spot size, an intensity, and the like, which can penetrate the cross section of the workpiece W according to the thickness of the workpiece W or the material. The output power of the second laser light L2 is smaller than that of the first laser light L1, and the spot size of the second laser light L2 may also be smaller than that of the first laser light L1.

Here, the tapered region TPA refers to a region from a point where the thickness of the workpiece W of the processing surface PA decreases to the opposite surface of the processing surface, and a point where the thickness of the workpiece W in the taper T is 70% to 30% may correspond to the tapered region TPA.

In fig. 15 (e), it was confirmed that the taper T was reduced by the laser processing of fig. 15 (d). As such, when the taper T is reduced or removed, the picture ratio in the display panel can be further increased.

The embodiment of fig. 16 is different from the embodiment of fig. 15 in that in (d) of fig. 16, the opposite surface of the processing surface PA of the existing processed object W is inverted so as to be close to the processing surface PA side on which laser processing is performed, and the rest is the same.

On the other hand, in the case where the open space TH is formed by the above-described laser processing method, micro cracks (micro cracks) occur in the portion irradiated with the laser light due to the impact and heat of the laser light. Fig. 17 is a photograph taken after the laser processing step of microcracks generated in the portion processed with the laser. Since such microcracks may develop into cracks of the effective area AA in the final product due to external impact or the like, a process of removing the microcracks is required to improve the commodity and reliability of the final product.

Hereinafter, a laser processing method of a display panel capable of removing microcracks according to an embodiment of the present invention will be described. A laser processing method capable of removing microcracks, which will be described later, may be included in the post-processing process according to the embodiments of the laser processing method of fig. 4 to 9, 11, and 13 described above and the embodiments of the laser processing method of fig. 14 and 15 described above.

In fig. 18 (a), a workpiece W including a crack surface CA where microcracks are generated by the laser processing is prepared.

In fig. 18 (b), laser light is irradiated to the crack surface CA, and microcracks are removed from the crack surface CA in the manner as in fig. 18 (c).

Wherein the laser is different from an ablation (ablation) laser according to the laser processing method described above. The laser of fig. 18 is a laser for polishing (polishing), and an infrared skin second (IR femto) laser is used, in this case, an optical unit including a 5-fold objective lens (object lens) is used. The repetition rate (repetition rate) of the laser is about 50kHz and the output power is about 50W.

Fig. 19 is a graph comparing the rigidity and the surface roughness of the crack surface CA subjected to laser polishing using the above laser light.

Fig. 19 (a) is a photograph of a workpiece in which microcracks are present because the laser polishing of fig. 18 is not performed, and fig. 19 (b) is a photograph of a workpiece in which microcracks are removed after the laser polishing of fig. 18 is performed. When the rigidity of the two samples was compared, it was confirmed that the sample of fig. 19 (b) on which laser polishing was performed exhibited a rigidity increase rate of about 50% or more. The rigidity comparison is determined by comparing the degree of damage of the edge portion having the microcrack after the predetermined impact is applied to each sample. In the case of the sample of fig. 19 (b), it was confirmed by experiments that the damage was significantly reduced.

Fig. 19 (c) is a photograph of a crack surface in which microcracks are present because laser polishing is not performed, and fig. 19 (d) is a photograph of a crack surface in which microcracks are removed after laser polishing of fig. 18 is performed. By comparing the surface roughness of the two samples, it was confirmed that the arithmetic average height Sa (arithmetical mean height), maximum height Sz (Maximum height), root mean square height Sq (Root mean square height) of the samples of fig. 19 (d) on which laser polishing was performed were larger than those of the samples of fig. 19 (a).

The steps constituting the method according to the present invention may be performed in an appropriate order unless the order is explicitly described or to the contrary. The present invention is not limited to the order of the steps described above. All example or exemplary terms (e.g., etc.) used in the present invention are merely for the purpose of describing the present invention in detail, and the scope of the present invention is not limited by the above example or exemplary terms unless limited by the claims. Also, it will be understood by those skilled in the art that various modifications, combinations, and alterations may be made depending on design conditions and factors within the scope of the appended claims or equivalents thereof.

The inventive concept should therefore not be limited to the embodiments described above, but the following claims and all equivalents and modifications equivalent to those claims are intended to fall within the scope of the inventive concept.

Claims

1. A laser processing method for irradiating a workpiece with a laser beam output from a laser oscillator to form an open space in the workpiece by using an optical unit having a mirror and a lens,

the laser processing method comprises the following steps:

a step of preparing a workpiece having a machining surface on one surface;

a step of oscillating the laser by operating a laser oscillator, and selecting a processing position by the optical unit;

a first processing step of irradiating a first laser beam along a first path on a processing surface of the object to be processed;

a second processing step of irradiating a second laser beam along a second path on a processing surface of the object to be processed; and

and a step of forming an open space in the workpiece by removing the dummy formed after the laser processing.

2. The laser processing method according to claim 1, wherein,

the processing surface of the object to be processed includes a sample region included in a final product, a virtual region not included in the final product, and a processing region corresponding to a boundary between the sample region and the virtual region,

In the first processing step, irradiating the first laser along a first path on the dummy area, and forming a first pattern including a plurality of first holes corresponding to the first path,

in the second processing step, the second laser is irradiated along a second path on the processing region, and a second pattern including a plurality of second holes is formed corresponding to the second path.

3. The laser processing method according to claim 2, wherein,

the output power of the first laser is smaller than the output power of the second laser, and the width of the first hole is smaller than the width of the second hole.

4. The laser processing method according to claim 1, wherein,

the object to be processed has a cross-sectional structure in which a plurality of films are laminated,

in the first processing step, irradiating the first laser along a first path on the processing region to form a first pattern including a plurality of recesses,

In the second processing step, the second laser is irradiated along a second path identical to the first path to form a second pattern including a processing hole.

5. The laser processing method as claimed in claim 4, wherein,

the first laser removes a portion of the plurality of films near the processing surface, and the second laser removes a remaining film not removed by the first laser.

6. The laser processing method according to claim 1, wherein,

in the first processing step, irradiating the first laser light along a first path on the sample region,

in the second processing step, the second laser is irradiated along a second path on the processing region.

7. The laser processing method as claimed in claim 6, wherein,

forming a plurality of first lines formed by connecting a plurality of fine grooves according to the thickness of the object to be processed on the first path by irradiating the first laser beam,

And forming a pattern including a plurality of holes for removing the object to be processed along the second path by irradiating the second laser.

8. The laser processing method according to claim 1, wherein,

the object to be processed includes a sample region included in a final product, a virtual region not included in the final product, and a processed region corresponding to a boundary between the sample region and the virtual region,

in the first processing step, the first laser is irradiated along a first path on the processing region,

in the second processing step, the second laser light is irradiated to a second position on the virtual area.

9. The laser processing method as claimed in claim 8, wherein,

forming a filament on the workpiece along the first path by irradiating the first laser beam,

and applying heat to the object to be processed at the second position by irradiating the second laser light to melt.

10. A laser processing method for irradiating a workpiece with a laser beam output from a laser oscillator to form an open space in the workpiece by using an optical unit having a mirror and a lens,

the laser processing method comprises the following steps:

a step of preparing a workpiece having a machining surface on one surface;

continuously and repeatedly irradiating laser light to the processing region and different positions on a virtual region adjacent to the processing region; and

11. The laser processing method according to claim 10, wherein,

the laser processing method comprises the following steps:

a first step of irradiating laser light at a first position on the processing region at a first time;

a second step of irradiating the laser light to a second position on the virtual area adjacent to the first position at a second time successive to the first time;

a third step of irradiating the laser light to a third position on the processing region adjacent to the first position at a third time subsequent to the second time; and

A fourth step of irradiating the laser light to a fourth position on the virtual area adjacent to the third position at a fourth time subsequent to the third time,

and repeatedly executing the first step to the fourth step.

12. The laser processing method as claimed in claim 11, wherein,

in the second step, the laser light is not irradiated to a second position on the virtual area adjacent to the first position but is suspended from being irradiated at a second time subsequent to the first time,

in the fourth step, the irradiation of the laser light is suspended without being irradiated to a fourth position on the virtual area adjacent to the third position at a fourth time subsequent to the third time.

13. The laser processing method according to claim 10, wherein,

the step of irradiating the laser is a step of discontinuously and repeatedly irradiating the laser to different positions on the processing region.

14. The laser processing method according to claim 1 or 10, wherein,

the step of removing the virtual object further comprises the following steps:

and a third processing step of irradiating a third laser to a third position corresponding to a taper formed by removing the dummy to reduce the size of the taper.