TW201736029A - Mirror cutting method without processing sectional ends of a mirror - Google Patents

Abstract

The present invention set a time difference for plural tiny inline laser beam focuses in a depthwise direction, such that non-permeable denaturations occur sequentially along the depthwise direction to seek light absorption, so as to increase a crack length by the aforementioned interactions. The focal position is moved in high speed along the depthwise direction of the cutting, and a sectional cut end of a mirror is not processed in order to increase the cutting depth and obtain a mirror section and a high anti-breaking strength for industrial laser cutting. The invention has the effects of preventing small cracks formed on sectional ends of a brittle transparent object, improving the anti-breaking strength of the product weakened by the concentrated stress, and avoiding dirty marks remained on the cut surface.

Description

End section of the section without mirror cut

The invention relates to a cross-sectional end non-machining mirror cutting method, in particular to a precision cutting for the purpose of achieving high-destructive strength in the cutting of the transparent brittle material without directly processing the end portion of the section, forming a mirror state after cutting the section. Broken processor.

Although the laser effectively functions to cut a transparent brittle material such as glass into a free shape, since fine cracks occur after cutting, it is easily broken and requires a post-treatment process. In the conventional alkali glass or the like, since there is an absorption band in the carbon dioxide gas laser, the thermal stress generated by the absorption of the glass by the laser light and the temperature rise can be cracked and fractured, and the cross section can be processed into a mirror surface. However, this method cannot process transparent bodies such as tempered glass, alkali-free glass, and sapphire. Therefore, the pulsed laser which is not absorbed by the transparent body is strongly concentrated, and the heat absorption of the transparent glass is caused to cause heat absorption, so that the temperature of the substance rises sharply, and the substance is evaporated, and thermal destruction is performed. The method of processing. However, since this method is only denatured in the high-intensity condensing portion of the small focus portion, the cutting is performed by processing the edge portion of the glass section or by cutting the inside with a large processing mark. Broken processing method. Therefore, after the cutting, fine cracks remain in the edge portion of the cross section, which causes the stress to concentrate and break. In addition, even if the surface and the back surface are not directly processed, natural cracks from the inside are different, and the source of fine cracks remains after processing.

When the laser light passing through the transparent glass is concentrated beyond a certain intensity, the glass is denatured by the nonlinear optical effect to generate light absorption, further enhancing the heat of the light. The absorption is more active, and the temperature of the substance rises sharply. As a result, the material breaks due to strong thermal stress. When the strength is further increased, the fouling is destroyed by the high electric field. Even in the case of relatively weak light, in order to facilitate cutting, when the surface or the back surface is simultaneously cut and cut, fine cracks occur at the edge portion of the cross section, and the strength is lowered. In order to avoid this, it is necessary to cut only the inside of the profile by thermal stress with inconspicuous processing marks, and use a mirror surface to induce flat cracks on the surface and the back surface to avoid artificial end face cracks. Therefore, it is necessary to cause the thermal stress cracking portion of the laser to be formed elongated only in the front and back directions. In the case where it is realized by one laser beam, when concentrating inside the transparent body, it is necessary to cause thermal stress cracking to occur in a length matching the depth of focus of the lens system. When the damage is increased, the lens is concentrated by a long focal length. However, since the diameter of the spot is increased in this case, the required laser output is also very large, and the processing mark is also enlarged. Causes the occurrence of micro cracks.

As shown in Fig. 1, when the difference in the morphology of the laser beam irradiated to the cross section of the transparent body is observed, when the surface or the back surface is irradiated, cracks occur at the end portions of the cross section, so that fine cracks are generated and damage is caused by the stress. When the center portion is irradiated, when the cut end face does not cause cracks, an optical system having a long focal length and a high-output laser are required, and as a result, a large processing mark remains, and cracks are generated and the crack is generated after the processing of the processed mark. Considering the absorption of the light due to denaturation of the transparent body, in order to connect the small focus from the deep to the shallow, the transparent body is processed at a certain depth, and after the process is finished, the depth is slightly shallowed and then processed, so that the processing is repeated. A method in which deep processing marks are formed in the depth direction and cut. Since this method performs the processing in the depth direction with a time interval, the processing marks at the respective depths are lost and interacted at the same time, and only the minute processing marks are simply deposited, and the mirror-like natural crack cannot be caused.

The method of utilizing the characteristics of the transparent body and the propagation of the light to the deep-filamented laser filaments is not only the lens concentrating, but the light is formed on the filament by the nonlinear effect generated by the transparent material itself. Because of the method Depending on the optical properties of the transparent body material, the formation of the filaments depends on the nature of the transparent body material. In addition, in order to form a portion from a shallow portion to a deep portion, since there is a difference between the transmission of light consumed from the near end and the absorption heating, the portion where the filament is generated does not contribute to uniform processing, and is formed into a filament. The difficulty of complex optical systems and high output lasers is required.

The transparent body changes the physical properties by high-intensity laser light, whereby the transparent body absorbs light, so that the temperature of the focal portion rises rapidly and a destructive reaction occurs, because the surface and the back surface are compared with the inside to be processed with low strength, so strong laser light is used. When the vicinity is processed, the surface and the back surface are first reacted, so that the inside of the vicinity cannot be processed. Therefore, in order to enlarge the depth of the processing section as much as possible, it is necessary to form the processed portion in a wide range inside, and thus it is necessary to perform appropriate output adjustment for each irradiation point.

In other words, when processing is performed using the laser control section concentrating position, in addition to the concentrating focus position of the laser light, in addition to the concentrating focus position of the laser light, it is necessary to adjust the intensity according to the depth of the material profile to implement the surface. , back or internal processing. By doing so, it is possible to prevent the occurrence of fine cracks due to the cutting of the edge of the section, the scattering of dust due to the processing, the precision of the processing, the damage of the tape attached to the underside of the processed product, and the significant increase in the profile of the processed product. Etc., resulting in obvious surface irregularities. When scanning a laser beam, it is easy to change the depth adjustment output, but the above factors must be considered when two or more pulses are interfered with each other and simultaneously irradiated.

As described above, since the processing of the transparent body is performed only at the focal portion where the light intensity is high, it is necessary to form a good cut surface morphology by controlling the inside of the cross section where the light intensity is absorbed. When the focus is short and a small focus is generated, the local temperature rise can be processed more neatly, but since the processing area is narrow, the processing to achieve the fracture cannot be performed. There are also problems with the processing of the surface and the back surface, which may cause damage to the tape. When forming a large breakable work mark, the telephoto is used. The optical system of the point, but because the focal spot is large at this time, if the focal spot is made larger, a large laser energy is required to cause damage. Moreover, the profile causing the damage is fouled and the crack is large. Therefore, the most ideal way is to use a laser irradiation method to produce a smooth profile in the cutting direction. However, the fibrillation production must have conditions for stably producing filaments, and with long filaments, it is difficult to balance the filament generating ability and the absorption loss. Thus, there is a need for a system that can optimally illuminate in a dispersed focus.

Prior technical literature

Patent literature

[Patent Document 1] JP-A-2008-264843

[Patent Document 2] JP-A-2015-110248

[Patent Document 3] JP-A-2013-022627

[Patent Document 4] JP-A-2011-159827

[Patent Document 5] JP-A-2009-190069

[Patent Document 6] JP-A-2014-212282

[Patent Document 7] JP-A-2014-117707

[Patent Document 8] JP-A-2012-240082

[Patent Document 9] JP-A-2012-186287

[Patent Document 10] JP-A-2015-129076

[Patent Document 11] JP-A-2015-099922

[Patent Document 12] JP-A-2009-037808

[Patent Document 13] JP-A-2015-050226

[Patent Document 14] JP-A-2015-030040

[Patent Document 15] JP-A-2015-030039

[Patent Document 16] JP-A-2007-229758

Non-patent literature

[Non-Patent Document 1] Measurement Science and Technology, 12 (2001) 1784-1794, Laser-induced breakdown and damage in bulk transparent materials induced by tightly focused femtosecond laser pulse.

The problem to be solved by the present invention is that a laser processing method has not yet been created in the industry, and the edge of the transparent brittle material such as tempered glass, alkali-free glass and sapphire is not directly formed without any fouling. The processing is carried out, and the cross section is mirror-like in terms of natural cutting without damaging the underlying tape for supporting the glass.

The main object of the present invention is to provide a cross-sectional end non-machining mirror cutting method, comprising: first, when a transparent brittle material composed of glass, sapphire or ceramic is cut by a laser, the transparent brittle material is cut off. The in-plane complex laser beam is oriented to connect the complex focus with a small time difference of the width of the laser pulse. Secondly, the focus portions are transformed into an absorber by a denaturation method, thereby absorbing light, causing thermal stress damage at each focus position, and avoiding incident light of each focus affecting each other to form a complex damage. point. Furthermore, mirror-like processing is performed by creating a continuous, slender, and subtle thermal destructive force by the fine interaction of the damage points and the stresses generated between the fracture points.

In the non-machining mirror cutting method of the cross-sectional end portion of the present invention, the method further comprises: cutting each of the laser beams, and adjusting each of the cut laser beams to an appropriate intensity according to the irradiation depth, thereby Let the laser light generate multiple focal points; set the time difference according to the closest focal distance of each other to collect light, and the time difference must be greater than a pulse width; the light collecting points are slowly staggered from deep to shallow, and a piezoelectric a high-speed oscillating element such as an element as an optical system that causes a group of focal points to vibrate toward the direction of travel of the laser; and in addition to moving the transparent body toward the cutting direction, The focus in the vertical direction is extended more in the depth direction and in the machine direction, so that fine cracks are generated in a deeper range, so that the surface and the back surface can be directly processed and left at the end of the section The machining mark, or through the internal machining point, naturally produces cracks, and then uses the correct crack depth to cut.

The invention cuts off with a laser beam, so that a plurality of light beams are collected into a smaller focus, and some delay time is reserved, and the transparent body cross-cutting depth is arranged in a straight line by the light sequentially, so that the transparent body occurs. It mutates and absorbs light so that the temperature rises, and then the vibration of the optical system causes the breaking action to travel in the cross-section direction, thereby expanding the section range and forming a desired section by the destructive force.

The transparent body laser cutting method used in the present invention has the advantages that long-distance processing of a part of the inner surface can be performed without using an ultra-high-intensity laser, or light can be passed through in a filament-like manner. Inside the transparent body, and without the need for edge edge processing, deeper processing marks can be left. In addition, the processing profile is less prone to microcracking and maintains high breaking strength to form a desired profile.

1‧‧‧Laser beam

2‧‧‧wavelength board

3‧‧‧ polarizer

4‧‧‧Zoom optical system

5‧‧‧ polarizer

6‧‧‧Mirror

7‧‧‧Mirror

8‧‧‧2nd pulse

9‧‧‧1st pulse

10‧‧‧Injection lens holder

11‧‧‧Injecting lens

12‧‧‧Injecting the lens

13‧‧‧High speed vibrator

14‧‧‧Support ring

15‧‧‧Support ring

16‧‧‧Delay adjustment components

17‧‧‧Vibration component driver

18‧‧‧object lens

19‧‧‧Double beam splitter combiner

20‧‧‧ Brittle transparent material

21‧‧‧ stage

23‧‧‧The stage

22‧‧‧Laser

24‧‧‧patterned workpiece

To further understand and understand the purpose, technical features and effects of the present invention, the following embodiments are described in detail with reference to the drawings: FIG. 1 is a schematic view of a conventional transparent body processing method; FIG. 3 is a schematic diagram of a transparent body cutting device for dividing a laser beam into two beams according to a preferred embodiment of the present invention; FIG. 4 is a schematic diagram of different laser light intensity and transmittance. relation chart; 5 is a diagram showing the relationship between the depths of different materials and the energy used in the transparent body processing according to the present invention; FIG. 6 is a schematic view showing a preferred embodiment of the double beam vibration processing method of the present invention; FIG. 7 is a system architecture of a preferred embodiment of the present invention. FIG. 8 is a schematic diagram showing the results of cross-section processing of different materials by the present invention; FIG. 9 is a schematic diagram showing the results of cross-sectional processing using different breaking strengths; and FIG. 10 is a schematic diagram of a system architecture in which the present invention is applied to an industry.

Referring to FIG. 2, the method of the present invention is performed by using two additional focal points that can generate denatured laser focus light (1000000 W/cm ² ) inside the laser, by implementing an additional time difference inside the transparent body. Irradiation, avoiding mutual interference, and making any point of the distance from the back surface to the surface of the transparent body independent and simultaneously denatured by light absorption, and effectively guiding the natural fracture by including a slender crack between the focal points.

Fig. 3 is an explanatory view showing a transparent body cutting device divided into two beams according to the present invention. Further, when two or more split beams are used, the same method can be expanded. The laser beam (1) having linear polarization is rotated in any polarization direction by the rotation of the half-wavelength plate (2). The rotated light is split by the polarizer (3) into a ratio of the polarization direction in the transmission direction and the reflection direction. The passing light adjusts the parallelism of the light beam by the zoom optical system (4). On the other hand, the reflected light is reflected by the mirrors (6), (7) and combined into a light beam by the polarizer (5). At this time, the transmitted light beam is combined with the pulse (8) and the pulse (9) with the pulse width larger than the reflected beam as the delay time, and is combined with the same optical axis. Light passes through the incident lens (11) and the reflective lens (12) to the objective lens (18). At this time, the incident lens (11) is slightly moved, and the focus position of the laser beam generated by the objective lens (18) is slightly moved. This movement is performed by a vibration element (13) such as a piezoelectric element that vibrates the distance between the incident lens and the reflection mirror at a high speed. get on. The piezoelectric element is axially symmetrically arranged on the holder (10) and vibrates at a high speed.

As shown in Fig. 4, when the laser light passes through the transparent body, almost all of the light is transmitted when the light energy is low. When the laser intensity is increased, the glass penetration will drop sharply. By exceeding this strength, it is possible to cause the transparent body to absorb light and overheat. However, it must be noted that the damage condition varies depending on the position (depth) of the illumination. For example, when laser light is irradiated, if the deep portion is irradiated, the back surface is destroyed, and if the light is irradiated, the surface is destroyed. For example, when laser light is irradiated, if the deeper part is to be irradiated, the back surface will be destroyed, and the lighter part will be damaged, because the inner surface is more damaged than the surface or the back surface, in other words The appropriate illumination intensity must be set according to the depth position.

For example, for the tempered glass shown in FIG. 5, the beam is divided into two according to the required internal thermal energy threshold, and the laser beam is divided according to the distribution ratio of the thermal energy of the beam for illumination, and FIG. 5 is used. An illustration of two split beams.

The concentrated laser beam is condensed on the transparent body to absorb light at a deep position in the cross section. Secondly, other incident laser beams having a delay time greater than the pulse width are then concentrated at a deeper position. First, an absorber is generated in the deep portion to avoid the generation of the absorber on the light path through which the next pulse passes, and to converge the second laser pulse. The two condensing points vary depending on the magnification of the lens used, and the distance between them is about 20 to 50 μm, and the two are irradiated at substantially the same time, so that long cracks which cannot be obtained when a single focus is generated in the cross-sectional direction are obtained. At this time, if the interior of the surface is to be irradiated, even if the intensity of the surface is weak, the laser must be processed, and the laser must be placed close to the surface, but too close to the surface will affect the internal processing, so it can only be used on the surface. machining. In addition, the back side is the same. If the focus is placed near the back side, the surface can only be machined instead of the inside. Therefore, as shown in FIG. 5, it is necessary to consider the laser intensity with respect to various upper depth limits when irradiating.

The diagram in Fig. 6 shows a case where the two focal points are moved at high speed while being processed while being divided into two beams. By using a stage equipped with a workpiece At the same time, the beam is vibrated in the depth direction of the transparent body, and the wider and flat fracture surface can be enlarged in the thickness direction, and the operation is naturally cut off toward the surface and the back surface.

The brittle transparent material should be a precision processor, and tempered glass, alkali-free glass, and sapphire are selected for testing. The thickness and surface state of the surface of the cross section are examined, and the breaking strength test is performed by external force application.

Figure 7 is an explanatory view of an embodiment of the apparatus of the present invention, and the double beam splitting combiner (19) is as shown in Fig. 3. After the laser beam (1) passes through the double beam splitter combiner (19), the first pulse (8) is processed by the object lens (18) reaching the deep portion of the transparent body. Then, the second pulse (9) reaches a shallower portion to process the transparent body (20). The beam is moved up and down in the depth direction by the vibrator inside the double beam splitting combiner. The machining is performed by means of a moving table (21). The stage is manufactured in a precise manner, and has an effect of limiting the variation range in the depth direction to 10 μm or less for the thickness of the transparent material.

Figure 8 shows the results of the examples. When a 10 ps, 100 Micro J pulsed laser and a 25 kHz piezoelectric vibration element were used for the test, when the tempered glass was tested, even if a 1000-fold magnification microscope section was used without a process mark, the surface structure could not be observed and the mirror surface state was observed. Since the alkali-free glass needs to be heated, a small amount of processing marks remain. When testing sapphire, because of its high heat resistance and high strength, it requires better thermal conductivity and high temperature. Although some processing marks appear, the ratio of mirror surface is higher. When the sapphire is tested, when the workpiece is viewed from directly above, the surface is naturally cracked because the surface is not cut, and although there is a crack, the gap is not reached, and dust does not occur. In addition, the thermal energy is also completely consumed in the internal processing, so the support tape attached to the workpiece causes the light intensity to be attenuated, but the tape is not burnt due to the laser light.

Using the same test conditions as in Example 1, the width was 70 mm and the length was A tempered glass of 180 mm, a thickness of 550 μm, and a depth of 90 μm was processed, and a three-point failure test was performed. Fig. 9 shows the test results after the breaking strength test of the tempered glass material after cutting. It can be seen from Fig. 9 that the cutting edge processing is performed for a group having a low breaking strength, and the group having a higher breaking strength is not performed. The edge of the profile is machined, so it is understood that the displayed value is high.

The tempered glass is cut by laser. However, since the product after cutting has a low breaking strength, various mechanical processing and chemical treatment are required after the processing, which is complicated, and time consuming and expensive. When this method is used, as shown in Fig. 10, by mounting the transparent brittle material (24) on the stage (23), it is not necessary to increase the processing including the free shape of the curved surface, and therefore there is an industrial advantage.

When using this method, a flat profile can be achieved. Transparent brittle materials have the characteristics of high melting point and resistance to compressive stress. In laser processing, since the high electric field intensity is obtained by concentrating the laser light at a small focus, the material is relatively easily broken, but it is dirty because the structure is broken. Conversely, the thermal stress damage caused by rapid heating of the laser and rapid cooling is easily dominated by the stress field, thus showing flatness damage such as a mirror state. Since the thermal stress damage occurs at an output density of about 1,000,000 MW per square centimeter, the area where the output density is achieved by selecting two points by the lens, and the two-point interaction crack occurs by simultaneous irradiation. The cutting of the flat can be effectively achieved.

When this method is used, a cutting material capable of maintaining high strength can be realized. Since the breakage of the brittle material is the starting point of the crack at the end of the cross section, the cross section, particularly the processing of the end face portion, is not performed during the cutting, and processing for assisting the destruction along the natural stress field is sought. Therefore, in order to naturally induce cracks, the edge portion of the section is a natural destruction of the terminal end, and the processing range must cover the vicinity of the edge. However, when a short focus lens is used to increase the intensity of the condensing, only a part of each cross section can be processed, so that a plurality of focal portions are simultaneously processed, or It is to make a focus part move at a high speed, or to use the two effects at the same time to process in the widest possible range. Thereby, if only a part of the processing forms a large failure, the cutting cannot be performed, and conversely, the smooth processing by the flatness of the deposition is achieved. The high-speed vibration system expands the vibration of a piezoelectric element of about 2 kHz to 30 kHz, and repeats the vibration of about 10 μm to 30 μm.

When using this method, dust can be avoided during processing. Since dust is generated during surface processing, it needs to be cleaned after the cutting operation. To avoid dust, the surface cut should be discarded. By irradiating a plurality of points at the same time, it is possible to prevent cracking of dust, and it is possible to prevent the occurrence of dust or the dust from scattering from the cut portion by cutting only the inside to reduce the processing marks, so that it can be used in a clean room or the like. machining.

When processing using this method, keep the tape under the material from damage. By concentrating the lens system with a short focal length, the processing is performed with the internal processing laser intensity. However, since the tape surface is reduced by the energy passing through the processing portion, the laser intensity is extremely lowered, and the condition that the tape is not processed can be selected. .

Thick materials can be processed using this method. In the past, thick materials required a strong laser to condense the lens with a long focus, but the focus portion became large and formed a process stain. Therefore, according to the present invention, it is possible to cut a thick material by arranging a plurality of focus positions in the cross-sectional direction or moving a focus at a high speed to be cut in an easily broken state.

The foregoing is only a few preferred embodiments of the present invention, but the scope of the claimed invention is not limited thereto, and the technical contents disclosed in the present invention are disclosed by those skilled in the art. Equivalent changes that can be easily considered are within the scope of protection of the present invention.

1‧‧‧Laser beam

2‧‧‧wavelength board

3‧‧‧ polarizer

4‧‧‧Zoom optical system

5‧‧‧ polarizer

6‧‧‧Mirror

7‧‧‧Mirror

8‧‧‧2nd pulse

9‧‧‧1st pulse

10‧‧‧Injection lens holder

11‧‧‧Injecting lens

12‧‧‧Injecting the lens

13‧‧‧High speed vibrator

14‧‧‧Support ring

15‧‧‧Support ring

16‧‧‧Delay adjustment components

17‧‧‧Vibration component driver

18‧‧‧object lens

Claims (2)

A cross-sectional end non-machining mirror cutting method, comprising: when a transparent brittle material composed of glass, sapphire or ceramic is cut by a laser, a plurality of laser beams are oriented in the cut surface of the transparent brittle material, The plurality of focal points are connected by a time difference of a laser pulse width; the focus portions are transformed into an absorber by a denaturation method, thereby absorbing light, causing thermal stress damage at each focus position, and avoiding each The incident light of a focus affects each other to form a plurality of break points; and by the fine interaction of the break points and a stress generated between the break points, to produce a continuous, slender and subtle thermal damage Force to perform a mirror-like process. The cross-sectional end non-machining mirror cutting method described in claim 1 further includes: cutting each of the laser beams, and adjusting each of the cut laser beams to the irradiation depth according to the irradiation depth. a suitable intensity, whereby the laser light produces the focus; the time difference is set according to the closest focal distances of each other to perform a set of light, and the time difference must be greater than the width of the laser pulse; The light collecting point is slowly staggered, and a high-speed oscillating element such as a piezoelectric element is used as an optical system to vibrate the focus toward the laser traveling direction; and in addition to moving the transparent brittle material in the cutting direction, The focal points arranged in the vertical direction in the depth direction are further expanded in the depth direction and the processing direction, thereby generating fine cracks in a deeper range, so that the surface and the back surface can be directly processed and left at the end of the section The lower processing marks, or through the internal processing points, naturally produce cracks, and then use the correct crack depth to cut.