Laser processing device

Abstract

To provide a laser processing device capable of reducing adhesion of ultra minute dust to an optical component surface.SOLUTION: A laser processing device includes: a blower that causes outside air to flow through a filter into an accommodation body, the accommodation body accommodating a plurality of optical components through which each laser beam emitted from a laser oscillator passes sequentially; a discharge port for discharging the outside air caused to flow into the accommodation body to the outside; a scanner unit for causing the laser beams that have passed through the optical components of the accommodation body to scan in a two-dimensional direction on a substrate; and a control section that controls an operation of each part of the processing device. The accommodation body includes a discharge electrode and an insulator connected to a high-voltage supply device. The control section controls the high-voltage supply device to apply high-voltage to the discharge electrode so as to charge the insulator.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a laser processing apparatus for drilling holes by irradiating a laser onto, for example, a printed circuit board. [Background technology]

[0002] Some conventional laser processing devices include a laser unit that houses an oscillator, a reflecting member, a lens, and other optical components, and a scanner unit that scans the laser light irradiated from the laser unit in two-dimensional directions on a workpiece. Some such laser processing devices supply outside air, from which dust has been removed by a filter, to the laser unit to create a positive pressure inside the laser unit and prevent dust from entering from the outside, as disclosed in, for example, paragraph 0015 of Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-70055 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in such a laser processing device, very fine dust (particles) that cannot be removed by the filter may enter the laser unit and adhere to the laser entrance / exit surface of the optical component (hereinafter, also referred to as the "surface of the optical component" or the "surface of the optical component"). When dust adheres to the surface of the optical component, the laser absorption rate at the surface increases, and the absorbed laser turns into heat, raising the temperature of the optical component and increasing the thermal lens effect, which changes the laser characteristics and causes a decrease in processing quality. It may also cause burnout of lenses, etc. Therefore, it is desired to reduce the adhesion of fine dust that cannot be removed by a filter to the surface of the optical component. Patent Document 1 discloses a configuration for removing dust attached to the optical component at a predetermined timing, but does not disclose a configuration for reducing the adhesion of dust to the surface of the optical component.

[0005] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a laser processing apparatus capable of solving the above-mentioned problems and reducing adhesion of very fine dust particles to the surfaces of optical components. [Means for solving the problem]

[0006] In order to solve the above-mentioned conventional problems, the present invention provides a laser processing apparatus comprising a container that houses a plurality of optical components through which laser light emitted from a laser oscillator passes in sequence, the container having a blower that flows outside air into the container through a filter and an exhaust port for exhausting the outside air that has flowed into the container to the outside, a scanner unit that scans the laser light that has passed through the optical components of the container in a two-dimensional direction on a substrate, and a control unit that controls the operation of each part of the processing apparatus, the container comprising a discharge electrode and an insulator connected to a high voltage supply device, and the control unit controls the high voltage supply device to apply a high voltage to the discharge electrode, thereby charging the insulator. Effect of the Invention

[0007] According to the present invention, it is possible to provide a laser processing apparatus capable of reducing adhesion of very fine dust particles to the surfaces of optical components. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing a structure of a laser processing apparatus in one embodiment of the present invention. [Diagram 2] 1 is a schematic diagram for explaining a structure of a laser unit of a laser processing apparatus in one embodiment of the present invention. FIG. [Diagram 3] 1A to 1C are diagrams illustrating an insulator of a laser processing device in an embodiment of the present invention. [Figure 4] 5A to 5C are diagrams illustrating a charging operation of an insulator in a laser processing apparatus according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiment of the present invention will be described along with the examples with reference to the drawings. In the following description, the same reference numerals are given to equivalent parts, and the description will be omitted. In addition, the following mainly shows what is considered necessary to explain this embodiment, and does not show everything necessary as a laser processing device. The laser processing device has various components, connection lines, and control functions other than those described here, but they are omitted here.

[0010] FIG. 1 is a schematic diagram showing the structure of a laser processing device in one embodiment of the present invention. 1 is a laser unit that has multiple optical components installed inside and emits laser light L1 to a scanner unit 3, and a telescopic duct 2 is installed between the laser unit 1 and the scanner unit 3 to prevent dust in the air from entering the inside of the laser unit 1 and the scanner unit 3. The telescopic duct 2 telescopically expands and contracts as the scanner unit 3 moves in the Z direction. The scanner unit 3 is provided with a pair of galvano scanners and a condenser lens (not shown), and the laser light L1 incident on the scanner unit 3 is deflected in an arbitrary direction, so that the laser light L2 scans a substrate 4 in two-dimensional directions (XY directions). 19 is a high-voltage supply device, which will be described in detail later.

[0011] Reference numeral 4 denotes a substrate to be processed, and 5 denotes a table on which the substrate 4 is placed. The table 5 can be moved relative to the laser unit 1 and the scanner unit 3 by moving it in the X and Y directions in the figure. The substrate 4 is divided into processing areas determined based on the practical diameter of the condenser lens, and when processing in one processing area is completed, the table 5 is moved horizontally to position the center of the next processing area on the central axis of the condenser lens. Reference numeral 6 denotes a control unit for controlling the operation of each part of the laser processing apparatus, such as the laser unit 1, the scanner unit 3, the table 5, and the high voltage supply device 19, and is realized by, for example, a device mainly composed of a program-controlled processing device.

[0012] Fig. 2 is a schematic diagram for explaining the structure of a laser unit of a laser processing device in one embodiment of the present invention, and Fig. 3 is a diagram for explaining an insulator of a laser processing device in one embodiment of the present invention. The same numbers are used for the same parts as in Fig. 1, and only the parts necessary for explaining the embodiment of the present invention are shown.

[0013] Inside the laser unit 1, the laser light emitted from the laser oscillator 7 passes through an optical system consisting of a plurality of optical components that pass through each of them in sequence, and is then emitted from the laser unit 1. As shown in FIG. 2, the optical system in this embodiment includes a mirror 8 and a mirror 9 that reflect the laser light L3 emitted from the laser oscillator 7, an acousto-optical element (AOM) 10 that splits the laser light reflected by the mirror 9 into a non-processing laser light that is absorbed by a damper (not shown) and a processing laser light L4, a beam diameter adjustment lens 11 into which the laser light L4 split for processing by the AOM 10 is incident, a mirror 12 that reflects the laser light that has passed through the beam diameter adjustment lens 11, and a transmission plate 13 that prevents dust from entering the opening through which the laser light reflected by the mirror 12 is emitted from the laser unit 1. The laser light that has passed through the transmission plate 13 corresponds to L1 in FIG. 1. Note that the beam diameter adjustment lens 11 is shown as one lens here, but is actually composed of a plurality of lenses. The laser unit 1 in this embodiment forms a housing that houses the optical components, the laser oscillator 7, and the like described above.

[0014] Reference numeral 14 denotes a blower, which has the function of letting outside air flow into the laser unit 1 and is constantly operating while the power of the laser processing device is turned on. Reference numeral 15 denotes a filter, which removes dust from the outside air flowing into the laser unit 1 by the blower 14. The outside air flowing in by the blower 14 has a wind pressure that does not cause the laser light to fluctuate even when it is blown against each optical component. Reference numeral 16 denotes an exhaust port, which is connected to a dust collector (not shown) and exhausts the gas inside the laser unit 1 to the outside, but has a structure like a check valve that prevents gas from entering from the outside. Therefore, the inside of the laser unit 1 is under positive pressure to prevent dust from entering from the outside. Note that a filter with high dust collection efficiency, such as a HEPA filter, is used as the filter 15.

[0015] Reference numeral 17 denotes a flat insulator, made of, for example, a baked material. The insulator 17 is disposed in close proximity to the laser light reflecting surfaces of the mirrors 8, 9, and 12, the laser light incident surface and exit surface of the acousto-optical element 10, the laser light incident surface and exit surface of the beam diameter adjustment lens 11, and the laser light incident surface of the transmission plate 13 in a direction substantially parallel to each of the surfaces, and is detachably disposed relative to the laser unit 1. Each insulator 17 is sized to cover the entire surface of the laser incident surface or exit surface of the optical component with which it faces. Each insulator 17 is provided with a through hole 21 at a position through which the laser light passes, so as not to prevent the laser light from entering or exiting each optical component. Specifically, in the insulator 17 disposed at a position facing the mirrors 8, 9, and 12, for example, as shown in FIG. 3(a), a through hole 21 is provided at each of the positions through which the laser light entering the mirror passes and the laser light exiting from the mirror passes. In addition, in the insulator 17 disposed at a position facing the AOM 10, the beam diameter adjusting lens 11, and the transmitting plate 13, a through hole 21 is provided at a position through which the laser light passing through the lens 11 or outgoing therefrom passes, as shown in Fig. 3(b), for example. The through hole in the insulator facing the outgoing surface of the AOM 10 has a horizontally oval shape so as to pass both the processing laser and the non-processing laser.

[0016] Reference numeral 18 denotes a needle-shaped discharge electrode that generates a corona discharge, and is disposed so that the needle tip faces the rear surface of each of the insulators 17 in the laser unit 1, opposite the surface facing the optical component. Each discharge electrode 18 is connected to a high-voltage supply device 19, and is fixed in the unit via a mounting base (not shown) made of ceramic or the like. The high-voltage supply device 19 applies a high voltage to the discharge electrode 18, and is controlled by the control unit 6 to operate at any timing. Although the present embodiment has been described with reference to an example in which a plurality of discharge electrodes 18 are connected to one high-voltage supply device, each discharge electrode 18 may be provided with one high-voltage supply device.

[0017] The laser processing apparatus in this embodiment is configured as described above, and charges the insulator 17 arranged opposite the optical component, and electrostatically attracts dust around the insulator 17, thereby reducing adhesion of dust to the optical component. The laser processing apparatus in this embodiment operates as follows under the control of the overall control unit 6 to charge the insulator 17. A high voltage is applied to each discharge electrode 18 from the high voltage supply device 19 at any timing. FIG. 4 is a diagram explaining the charging operation of the insulator of the laser processing apparatus in one embodiment of the present invention. Corona discharge occurs from the needle tip of the discharge electrode 18 to which a high voltage is applied, and negative ion particles are emitted toward each insulator 17 as shown in FIG. 4. The negative ions collide with the insulator 17, so that the insulator 17 is charged. Then, the dust around the charged insulator 17 is attracted to the insulator 17 by Coulomb force before adhering to the optical component.

[0018] The timing of discharging the insulator is arbitrary, but if the average operating time from when the insulator is charged to when it is no longer charged is investigated in advance by experiments, etc., and the insulator is charged every time that time passes, the dust collection and adsorption effect of the insulator can be maintained. When the insulator is no longer charged, it will no longer be able to adsorb surrounding dust, but dust that has already adhered will remain attached due to van der Waals forces, so the dust will not scatter around. In addition, each insulator 17 is detachably arranged inside the laser unit 1, so that it can be removed when the insulator is no longer charged, cleaned, and placed again.

[0019] In this embodiment, the discharge was performed on the surface of the plate-shaped insulator that does not face the optical components, but the discharge may be performed on the surface that faces the optical components. Also, in this embodiment, the insulators are disposed for all the optical components in the laser unit, but they may be disposed only for the optical components for which it is particularly desired to reduce the adhesion of dust.

[0020] As described above, the present invention can adsorb extremely fine dust that cannot be removed by the filter by charging the insulator arranged in the laser unit. Therefore, the amount of dust in the laser unit can be reduced, and therefore the dust adhering to the optical components can also be reduced. Furthermore, the present invention is arranged such that the plate-shaped insulator is large enough to cover the entire surface of each optical component and is parallel to these surfaces, so that the adhesion of dust between the surface of the optical component and the insulator to the optical components can be effectively reduced. Furthermore, the present invention reduces the amount of dust adhering to the optical components, so that the interval between cleaning the optical components can be extended and the time of processing stoppage for cleaning can be reduced, thereby improving productivity. [Explanation of symbols]

[0021] 1: laser unit, 2: telescopic duct, 3: scanner unit, 4: board, 5: table, 6: control unit, 7: laser oscillator, 8: mirror, 9: mirror, 10: acousto-optic element (AOM), 11: beam diameter adjustment lens, 12: mirror, 13: transmission plate, 14: blower, 15: filter, 16: exhaust port, 17: insulator, 18: discharge electrode, 19: high voltage supply device, 21: through hole

Claims

1. A housing that houses a plurality of optical components through which laser light emitted from a laser oscillator passes in sequence, the housing having a blower that introduces outside air into the housing through a filter, and an exhaust port that exhausts the outside air that has been introduced into the housing to the outside; a scanner unit that scans the laser light that has passed through the optical components of the housing in a two-dimensional direction on a substrate; A laser processing apparatus including a control unit that controls the operation of each unit of the processing apparatus, The container includes a discharge electrode and an insulator connected to a high voltage supply device, The control unit controls the high voltage supply device to apply a high voltage to the discharge electrode, thereby charging the insulator. A laser processing device comprising:

2. The insulator is flat and disposed substantially parallel to the surface of the optical component.

2. The laser processing device according to claim 1 .

3. The insulator is sized to cover the surface of the optical component.

3. The laser processing device according to claim 2 .

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