JP6914710B2 - Light reflector - Google Patents

Description

For example, in a laser processing apparatus, a galvanometer mirror for reflecting a laser emitted from a laser oscillator is provided in order to irradiate a plurality of positions on a workpiece with a laser. In the present invention, such light reflection is provided. Regarding the device.

As the above-mentioned light reflecting device, conventionally, as disclosed in, for example, Patent Documents 1 and 2, a single mirror for reflecting a laser, an elastic support member for supporting the mirror on the back surface or the periphery, and a mirror. There is known an electromagnetic mechanism that drives the outer peripheral side of the mirror in the vertical direction to incline the mirror in an arbitrary direction. In this light reflecting device, by controlling the electromagnetic mechanism to change the tilting direction and tilting angle of the mirror, the incident laser is reflected by one mirror to different positions in the two-dimensional direction.

In such a conventional light reflecting device, the device can be made smaller than the galvano mirror in which the mirror is rotated by a motor, but since the position adjusting system has an elastic member interposed therebetween, the elastic member receives stress. It is necessary to study the design of an elastic member that can withstand stress, and there is a drawback that it is difficult to select the shape and material of the elastic member. In addition, if the elastic member is made larger or has a high elastic modulus in an attempt to reduce the stress of the elastic member to the allowable value or less, the drive torque in the drive mechanism increases and the drive stroke decreases, which makes it difficult to design the drive mechanism. be.

Furthermore, in the structural method in which the mirror is supported by an elastic member, it is necessary to design the mirror to have low rigidity in the tilt direction and high rigidity in the non-tilt direction, but the rigidity in the tilt direction and the non-tilt direction are completely independent. It is difficult to design. There is a correlation between the two, and if the rigidity in the tilt direction is lowered, the rigidity in the non-tilt direction is also lowered, and there is a problem that resonance in the non-tilt direction occurs when the mirror is driven in a high frequency region.

Japanese Unexamined Patent Publication No. 11-281925 Japanese Unexamined Patent Publication No. 2016-180832.

Therefore, an object of the present invention is to provide a light reflecting device capable of selecting the shape and material of the member to be used, designing the drive mechanism more easily than before, and reducing resonance in the non-tilting direction.

In order to solve the above problems, in the invention disclosed in the present application, a typical light reflecting device has a light reflecting member having a reflecting surface for reflecting incident light and the opposite of the reflecting surface of the light reflecting member. A magnet located on the surface side of the surface, which includes a circular magnet located in the center of the surface side opposite to the reflective surface and a fan-shaped magnet located around the surface side opposite to the reflective surface. Then, a member that attracts the light reflecting member in a direction perpendicular to the reflecting surface, a plurality of inelastic support portions that support the surface side of the light reflecting member opposite to the reflecting surface, and each of the inelastic support portions. Is provided with a piezoelectric element for driving in the direction opposite to the suction direction.

According to the present invention, it is possible to obtain a light reflecting device that can easily select the shape and material of the member to be used and design the drive mechanism as compared with the conventional case, and can reduce resonance in the non-tilting direction.

It is a vertical cross-sectional view of the light reflector which becomes one Example of this invention. FIG. 1 is a cross-sectional view taken along the line AA in FIG. It is a figure for demonstrating the magnetic circuit in FIG. It is a schematic block diagram of the control system of the light reflector which becomes one Example of this invention. It is a figure which shows the relationship between the irradiation position on the workpiece and the voltage applied to a piezoelectric element. It is a vertical cross-sectional view of the light reflector which becomes another Example of this invention.

(Example)
FIG. 1 is a vertical cross-sectional view of a light reflecting device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, showing a state in which the mirror accommodating portion is viewed from above without a mirror. Is. The cross-sectional view taken along the line BB in FIG. 2 is exactly the same as that shown in FIG.

In FIGS. 1 and 2, 1 is a circular pedestal forming the base of the light reflecting device, and 2 is a circular mirror accommodating portion provided on the pedestal 1. The mirror accommodating portion 2 houses a circular mirror 3 in the upper part, a circular permanent magnet 4 in the center of the lower part, fan-shaped permanent magnets 5a, 5b, 5c around the lower part, and fan-shaped piezoelectric elements 6a, 6b, 6c, respectively. Will be done. The permanent magnets 5a, 5b, 5c and the piezoelectric elements 6a, 6b, 6c are arranged so that their centers in the circumferential direction are alternately arranged at intervals of 60 degrees. The sizes of the permanent magnets 5a, 5b, and 5c are equal to each other, and the same applies to the piezoelectric elements 6a, 6b, and 6c.

The mirror 3 is made of, for example, high-hardness electromagnetic stainless steel, which is one of the soft magnetic materials, and is produced by mirror-finishing the light receiving surface of the laser. Reference numeral 8 denotes a yoke made of a soft magnetic material arranged directly under the permanent magnets 5a, 5b, and 5c, and the magnetic field lines emitted from the permanent magnets 5a, 5b, and 5c are shown by arrows in FIG. , A magnetic circuit is formed so as to pass through the yoke 8 and return to each of them. Therefore, the mirror 3 is always sucked downward, and a force for suppressing the movement in the lateral direction acts by this suction force, so that the mirror 3 is held in the mirror accommodating portion 2. Reference numeral 9 denotes a spacer arranged directly below the yoke 8, and the suction force for the mirror 3 can be adjusted by adjusting the thickness thereof.

FIG. 3 is a diagram for explaining the above magnetic circuit. In FIG. 3, the permanent magnets 5a and 5c whose centers in the circumferential direction are separated from each other by 120 degrees are drawn so as to be separated by 180 degrees for convenience. The magnetic field lines emitted from the respective north poles of the permanent magnets 5a and 5c pass through the mirror 3, the permanent magnet 4, and the yoke 8 in this order as shown by the arrows, and return to the respective south poles. The same applies to the magnetic field lines emitted from the north pole of the permanent magnet 5b.

The lengths of the piezoelectric elements 6a, 6b, and 6c in the vertical direction can be changed in the figure by controlling the applied voltage. An inelastic mirror support portion 10 is provided above the piezoelectric elements 6a, 6b, and 6c. The mirror support portion 10 is for making it possible to adjust the height of the uppermost portion of the sphere member 11 by adjusting the thickness and the sphere member 11 in which the lower portion of about one-third of the entire sphere is horizontally cut. The cut surface of the spherical member 11 is adhered to the spacer 12.

With the above configuration, the mirror 3 is housed in the mirror housing part 2 in a state of being attracted by the permanent magnet to a position determined by the height of the mirror support part 10. Further, due to this suction force, a force for suppressing the movement of the mirror 3 is exerted in the lateral direction as well. The positions of the mirror support portions 10 are adjusted so as to be 120 degree apart from each other, that is, to match the apex positions of an equilateral triangle centered on the center of the mirror 3, and the mirror 3 has three points on the back surface. It has a structure supported by point contact by the mirror support portion 10 in the above.

Reference numeral 13 denotes a damper for improving the damping property of the vibration generated in the mirror 3, which is inserted between the wall 14 for forming the mirror accommodating portion 2 and the mirror 3.

In the above configuration, the voltages applied to the piezoelectric elements 6a, 6b, and 6c are changed to change the heights of the three mirror support portions 10, the rotation angle α centered on the horizontal axis passing through the center of the mirror 3, and perpendicular to the horizontal axis. The mirror 3 in a state of being constantly sucked downward can be tilted by an arbitrary angle in an arbitrary direction by rotating the rotation angle β about the vertical axis passing through the center of the mirror 3 in the direction, and has been incident. The laser can be reflected to different irradiation positions P1, P2, P3 ... In the two-dimensional direction.

FIG. 4 is a schematic block diagram of a control system when the light reflecting device of this embodiment is used instead of the galvano mirror in the laser processing device.

In FIG. 4, reference numeral 15 denotes a laser machining control unit provided in the laser machining apparatus, which controls the execution of the entire machining operation. Inside the laser machining control unit 15, a laser scanning control unit 17 that controls the laser irradiation position on the workpiece 16 based on the given laser irradiation position information is provided. 18a, 18b, and 18c are piezoelectric element drive circuits that apply the voltage specified by the laser scanning control unit 17 to the piezoelectric elements 6a, 6b, and 6c in the light reflecting device 19 of the present embodiment, respectively. The light reflecting device 19 is controlled by the laser scanning control unit 17, reflects the laser L emitted from the laser oscillator, and has separate irradiation positions P1 in the two-dimensional direction including the X direction and the Y direction on the workpiece 16. P2, P3 ... Are irradiated.

Since each of the above-mentioned irradiation positions P1, P2, P3 ... Is determined by the rotation angles α and β of the mirror 3, as shown in FIG. 5, the rotation angles α corresponding to the irradiation positions P1, P2, P3 ... The relationship between β and the voltages Va, Vb, and Vc applied to the piezoelectric elements 6a, 6b, and 6c is obtained in advance, and this relationship is held in the storage means in the laser scanning control unit 17 as table information. The laser scanning control unit 17 reads the corresponding voltage Va, Vb, Vc information from the commanded irradiation positions P1, P2, P3 ... Information from the storage means, and corresponds to each of the piezoelectric elements 6a, 6b, 6c. Supply voltage.

According to the above embodiment, in a state where the mirror 3 is attracted by the permanent magnet to a position determined by the height of the inelastic mirror support portion 10, the mirror 3 is raised by the mirror support portion 10 in a direction resisting the attractive force. As a result, the position adjustment system does not involve an elastic member, and the shape and material of the member to be used and the design of the drive mechanism can be made easier than before.

Further, by attracting the mirror 3 with a permanent magnet, the mirror 3 is preloaded at a position determined by the height of the inelastic mirror support portion 10, so that the rigidity in the non-tilting direction can be increased. As a result, the natural frequency in the non-tilt direction becomes high, and resonance in the non-tilt direction when the mirror 3 is driven in a high frequency region can be reduced.

Further, by attracting the mirror 3 with a permanent magnet, the piezoelectric elements 6a, 6b, 6c are preloaded via the mirror support portion 10, so that the piezoelectric elements 6a, 6b may be weak against pulling and strong against pressing. , It is possible to obtain a light reflecting device that does not easily break down by taking advantage of the features of 6c.

In the above embodiment, the mirror 3 is made of a soft magnetic material with a mirror finish so that it can be attracted by a magnet. As another method for allowing the mirror 3 to be attracted by a magnet, for example, as shown in FIG. 6, the mirror 30 is made of a material having a light specific gravity other than a magnetic material, such as beryllium or aluminum, and is placed under the mirror 30. A base plate 31 made of a soft magnetic material that can be attracted by a magnet may be attached.

Although the mirror 3 is circular, it may have other shapes such as a square or a hexagon. In this case, each position of the spherical member 11 needs to match the apex position of the equilateral triangle whose center is in the center of the mirror 3.

Further, although the case where the mirror 3 is driven by the three mirror support portions 10 has been described, the number of the mirror support portions 10 may be more than 3, such as 4, 5, 6, and so on. .. Also in that case, in the same manner as described above, a piezoelectric element may be provided below each mirror support portion 10 to drive each of the mirror support portions 10.

1: Pedestal 2: Mirror accommodating part 3, 30: Mirror 4, 5a, 5b, 5c: Permanent magnet 6a, 6b, 6c: Piezoelectric element 8: Yoke 9, 12: Spacer 10: Mirror support part 11: Sphere member 13: Damper 15: Laser processing control unit 16 :: Work piece 17: Laser scanning control unit 18a, 18b, 18c: Piezoelectric element drive circuit 19: Light reflector 31: Base plate

Claims (5)

A light reflecting member having a reflecting surface that reflects incident light, and a magnet located on the surface side of the light reflecting member opposite to the reflecting surface, and located at the center of the surface side opposite to the reflecting surface. A circular one having a circular shape and a fan-shaped one located around the surface opposite to the reflecting surface, and the light reflecting member attracting the light reflecting member in a direction perpendicular to the reflecting surface, and the light reflecting member. Light reflection provided with a plurality of inelastic support portions that support the surface side opposite to the reflective surface, and a piezoelectric element for driving each of the inelastic support portions in a direction opposite to the suction direction. Device. The light reflecting device according to claim 1, wherein the light reflecting member is made of a magnetic material. The light reflecting device according to claim 1, wherein a member made of a soft magnetic material is provided on the surface side of the light reflecting member opposite to the reflecting surface. In the light reflecting device according to any one of claims 1 to 3, the light reflecting member is circular, and the inelastic support portion is provided at the apex position of an equilateral triangle centered on the center of the circle. A light reflecting device characterized by the fact that. In the light reflecting device according to any one of claims 1 to 4, by driving each of the plurality of piezoelectric elements, the light reflecting member reflects the incident light at different positions in the two-dimensional direction. A light reflecting device characterized in that the light reflecting member is tilted as described above.

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