JP2005305462A - Method and apparatus for breaking object by laser beam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and apparatus which can accurately break or cut an object composed of a material transparent or translucent with respect to a laser beam. <P>SOLUTION: This is a method to help breaking of the object transparent or translucent with respect to a laser beam. In this method, a physical or chemical change is caused inside the object by irradiating it with a laser beam and specifying the breaking position of the object as well as reducing the breaking resistance of the object at that breaking position. The laser beam may be a femtosecond pulsed laser beam. By the irradiation of the laser beam, there is continuously or intermittently caused physical or chemical change along the surface inside the object. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for breaking or cutting an object using laser light, a method for assisting in breaking or cutting an object, and a laser rupturing apparatus for breaking or cutting the object.

  Laser light is used to break or cut various objects, but it is also known that it can be used to break or cut materials transparent to laser light such as glass. For example, Japanese Patent Application Laid-Open No. 2000-233936 discloses a glass plate that is heated by irradiating laser light to a glass plate that moves in one direction, and sprayed with a refrigerant at a downstream side of the heating portion to rapidly cool the glass plate. A glass cutting device for dividing a plate is disclosed. According to the glass cutting device disclosed in the publication, the glass is heated by laser light, the glass is cooled by spraying a coolant, and the glass is cut by thermal stress caused by a temperature difference.

  In this method, the boundary between the part heated by the irradiation of the laser beam and the part cooled by blowing the coolant is unclear, and therefore the cutting position cannot be accurately controlled. There is a problem.

  Japanese Patent Application Laid-Open No. 2000-61677 discloses a technique for cutting a bonding panel for a liquid crystal display panel using laser light. According to the publication, the laser cutting device is configured to cut a cutting target before the laser irradiating a laser beam to a cutting target with a laser beam having a specific wavelength, A cutting groove forming means for forming a cutting start groove at the edge where the line starts and a cooling means for cooling the cutting line of the cutting object irradiated with the laser beam of the laser are included.

  In the case of this method and apparatus, it differs from the technique disclosed in the above publication in that it has a cutting groove forming means, but the temperature is raised by irradiating the laser beam to the glass, and immediately after the cooling means The point that glass is cut by the internal stress due to the temperature difference by cooling by is common. Therefore, even in the case of this method or apparatus, the cutting position cannot be accurately controlled as in the above technique.

Further, Japanese Patent Laid-Open No. 5-305467 discloses a method of cutting a light-transmitting material using a laser beam. A laser-absorbing paint is applied to at least one surface of the material, and the material Scanning the laser beam along the desired cutting line from the other surface side, heating the light transmissive material by the temperature rise of the light-absorbing paint that received the laser beam, and cutting the material by thermal stress This is the same as the previous technique. Therefore, this method also has a problem that the cutting position cannot be accurately controlled.
JP 2000-233936 A JP 2000-61677 A JP-A-5-305467

  The present invention has been developed to solve the above-described problems of the prior art, and an object of the present invention is to provide a technique capable of accurately controlling the breaking or cutting position of an object.

  In order to solve the above-mentioned problems, the present invention is a method for assisting in the breaking of a transparent or semi-transparent object with respect to laser light, wherein physical or chemical changes are made inside the object by laser light irradiation. There is provided a method for rupturing an object with a laser beam, which causes a rupture position of the object to be specified and a rupture strength of the object at the specified rupture position to be reduced.

  In the case of the method according to the present invention, not only the object is heated by the irradiation of the laser beam, but also the physical / chemical change is caused inside the object to reduce the breaking strength of the object. The object is broken or cut at the position. As a result, it becomes possible to control the position of breakage or cutting very accurately.

  According to a preferred embodiment of the present invention, femtosecond pulsed laser light is used as the laser light.

Among the techniques for cutting and processing materials by laser light irradiation, femtosecond (fs: ^10-12 seconds) pulsed laser light having a pulse width of less than 1 picosecond is used as laser light suitable for fine processing. There are methods for processing opaque materials and transparent materials. Although the application of the present invention is not limited to femtosecond lasers, femtosecond pulsed lasers are used as a preferred embodiment.

  When a laser beam is used to cause physical or chemical changes in the material, there is a threshold regarding the energy of the laser beam irradiated per unit area, and when the irradiation energy exceeds the threshold, the material undergoes a physical or chemical change. Is known to occur. In particular, when processing is performed using a femtosecond laser, unlike when using a carbon dioxide laser or nanosecond YAG laser, the physical and chemical changes only in the region where the laser beam intensity exceeds the material threshold. However, the change is limited to the region and has a feature that the neighborhood is hardly affected.

  Various physical and chemical changes can be caused by laser light irradiation. Examples of such changes include decomposition of material molecules, gasification, reduction in material strength, and change in rigidity. Taking advantage of this change caused by laser light, the physical strength of a specific part can be reduced, and breakage or cutting can be performed. In this case, a great feature is that the position of breaking or cutting can be accurately controlled.

  In conventional laser processing, most of the light energy irradiated to the work material is converted into thermal energy, and this heat causes processing by melting, decomposition, and scattering, whereas in femtosecond lasers, it is extremely short. Since energy concentrates on the work material over time, nanoplasma, nanoshock, breakdown, lattice distortion, shock waves are generated in a very short time, and ablation occurs before heat is generated, so the change is limited to the irradiated site Because it is done.

  In addition, when processing a transparent material using a femtosecond pulse laser, the focal point of the laser beam is located at a site below the surface, which may cause a three-dimensional physical / chemical change only inside. Is possible. Since the processing by the femtosecond pulse laser is processing using a nonlinear phenomenon such as multiphoton absorption, it is also characterized in that processing resolution exceeding the diffraction limit of the wavelength of irradiation light can be obtained.

  In still another embodiment of the present invention, the object is broken or cut by causing physical or chemical changes to occur inside the object continuously or intermittently along the surface by irradiation with the laser beam.

  When, for example, gasification is continuously performed along the surface of the object by laser light, the strength of the part decreases in a linear shape, and breaks easily along the line. This is the same even if gasification is performed intermittently. Therefore, if a slight bending force is applied to the object after this processing is performed, the object will break along the irradiated line.

  It is obvious that the object can be cut by performing gasification from the front surface to the back surface on the irradiation side and moving the gasified region, for example, linearly.

  The method of the present invention is not limited to the following, but for example, transparent or translucent glass, quartz glass, quartz, calcium fluoride, fluororesin, acrylic resin, polycarbonate, polyethylene, polyethylene with respect to laser light Terephthalate, polymethyl methacrylate, methyl methacrylate / styrene monomer copolymer, polypropylene, transparent ABS resin, transparent polystyrene, transparent epoxy resin, polyarate, polysulfone, polyethersulfone, transparent nylon resin, polybutylene terephthalate, polymethylpentene, polyimide It can be used to break or cut resins, phenol resins, phenoxy resins, cellulose films, and vinyl ester resins.

  These are used as a transparent plate material for various purposes, and are used, for example, as a flat plate for architectural use, a liquid crystal display device or a plasma display. In particular, so-called flat panel displays such as liquid crystal display devices generally have a flat laminated structure, and transparent plate materials that are these structures are broken or cut at high speed, inexpensively and with sufficient accuracy. There is a need to do so, and the method of the present invention is sufficient to meet these requirements.

  The present invention also includes a laser device including a laser light source and a condensing device, and irradiates a laser beam onto an object transparent or translucent to the laser beam to continuously or intermittently physics the object. -Propose a laser breaking device that can cause chemical changes and reduce the breaking strength of an object at that position.

  The above laser rupturing apparatus can be suitably used for carrying out the above-described method according to the present invention, and therefore, accurate rupturing or cutting of an object can be performed at low cost and at high speed without large equipment. .

  Preferred embodiments of the present invention will be described below with reference to the drawings. The following description and drawings are provided to aid the understanding of the present invention, and the present invention is naturally not limited to these embodiments.

  FIG. 1 schematically shows a state in which a plate-like object made of a transparent or translucent material is broken using the laser breaking device and the laser breaking treatment method according to the present invention.

  A laser beam 130 such as a femtosecond pulse laser supplied from the laser beam supply apparatus 100 is refracted by the condensing lens 110, inside the object 120 that is transparent or translucent to the laser beam, in the depth direction. The radius becomes the smallest in the vicinity of the center 140 (referred to herein as a focal position).

  FIG. 2 shows an enlarged view of the concentration of laser light near the object 120 and the focal point 140. In the vicinity of the focal point 140, the energy density of the laser beam is higher than a threshold value that causes a physical / chemical change in the object in the rugby ball-shaped region 150 indicated by oblique lines. The region 150 that exceeds the threshold is slightly separated from the front and back surfaces of the object, which means that a physical and chemical change occurs in the interior slightly away from the back surface of the object. ing. The laser beam 130 is incident from the front surface of the object, passes through the inside of the object, and exits from the back surface. However, the energy density is low near the back surface of the object. No change occurs. Here, the physical and chemical changes are destruction, evaporation, decomposition, modification, cutting, and processing of the material, but in the following description, they are simply referred to as destruction for the sake of simplicity.

  As shown in FIG. 3, when the region exceeding the threshold is moved slightly along the surface while moving the destruction region 210 by the laser beam while keeping the positions slightly separated from the front and back surfaces of the object, the inside of the object Will result in a continuous tubular cavity.

  As a result, the object is very easily broken along the cavity, and is broken along the cavity by applying a slight external force such as a bending force.

  The same effect can be obtained by moving the destruction area so that it reaches one surface of the object, and if the destruction area is moved with the destruction area reaching the front and back surfaces, The object can be cut by irradiation with laser light.

  Furthermore, the region to be destroyed by the laser beam does not need to be continuous. For example, by forming the destruction region intermittently along a straight line, it becomes very easy to break along the destruction region. It is the same as the case where it forms automatically. In this case, it goes without saying that the fracture region may reach the front and back surfaces.

  In the above embodiment, the present invention has been described mainly with the object processing using a femtosecond pulse laser in mind, but the present invention is not limited to the femtosecond pulse laser, and the object is limited to glass. It should be readily understood by those skilled in the art that this is not done.

The figure which showed typically the state which irradiates a laser beam to a target object based on this invention. The enlarged view which shows the positional relationship of the condensing position vicinity of a laser beam and a target object in the state shown in FIG. BRIEF DESCRIPTION OF THE DRAWINGS Drawing which shows the fracture | rupture of the board | plate material based on this invention typically.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Laser beam supply apparatus 110 Condensing lens 120 Object transparent or semi-transparent with respect to laser beam 130 Laser beam locus 140 Condensing position of laser beam 150 Area where energy density of laser beam exceeds threshold 160 Processing position 200 Flat plate Object (sheet glass)
210 Destroyed area

Claims (5)

  A method for assisting in the breakage of a transparent or semi-transparent object with respect to a laser beam, which causes a physical or chemical change inside the object by irradiation of the laser beam, specifies the break position of the object, and A method for breaking an object with a laser beam, which reduces the breaking strength of the object at a specified breaking position.   The method according to claim 1, wherein the laser beam is a femtosecond pulse laser beam.   The method according to claim 1 or 2, wherein physical or chemical changes are continuously or intermittently generated along the surface of the object by irradiation with the laser beam.   The object is transparent or translucent glass, quartz glass, quartz, calcium fluoride, fluorine resin, acrylic resin, polycarbonate, polyethylene, polyethylene terephthalate, polymethyl methacrylate, methyl methacrylate / styrene monomer Combined, polypropylene, transparent ABS resin, transparent polystyrene, transparent epoxy resin, polyarate, polysulfone, polyethersulfone, transparent nylon resin, polybutylene terephthalate, polymethylpentene, polyimide resin, phenol resin, phenoxy resin, cellulose film, vinyl ester 4. A method according to any one of claims 1 to 3, comprising a material selected from resins.   It is equipped with a laser device equipped with a laser light source and a condensing device, and irradiates a laser beam on a transparent or semi-transparent object with respect to the laser beam to continuously or intermittently change physical or chemical changes inside the object A laser rupturing apparatus that can be generated to reduce the rupture strength of an object at the position.

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