JP3607898B2 - Swing reflector device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oscillating reflecting mirror device, and more particularly to an oscillating reflecting mirror device that attaches a reflecting mirror to a rotating shaft and swings the reflecting mirror by rotating the rotating shaft.
[0002]
[Prior art]
A galvano scanner that scans a laser beam is used in a laser processing machine that punches holes in a printed circuit board for electronic circuits or a green sheet made of ceramic before firing. The galvano scanner (oscillating reflecting mirror device) includes a reflecting mirror that reflects a laser beam, a drive mechanism that swings the reflecting mirror, and a sensor that detects a rotation angle from a reference position with respect to the rotation direction of the reflecting mirror. Composed.
[0003]
The drive mechanism includes a permanent magnet and a coil. When the drive mechanism is operated, the coil generates heat and the temperature of the sensor rises. When the temperature of the sensor rises, the detection accuracy of the rotation angle of the reflecting mirror decreases. Further, the reflecting mirror may be thermally deformed by the incidence of the laser beam. When the detection accuracy of the rotation angle of the reflecting mirror is lowered or the reflecting mirror is thermally deformed, the incident position of the laser beam is changed.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide a oscillating reflector device in which the accuracy of the rotation angle of the reflector is not easily lowered even when a drive mechanism is operated.
[0005]
[Means for Solving the Problems]
According to one aspect of the present invention, a housing, a rotation shaft that is rotatably supported in the housing, and at least one end projects to the outside of the housing, and the rotation shaft at a portion projecting to the outside of the housing The reflecting mirror attached to the rotating shaft and swinging by the rotation of the rotating shaft, the coil wound around the portion of the rotating shaft in the housing, and the coil and the first gap are arranged so as to be spaced apart from each other. comprises a permanent magnet mounted to the housing, a sensor for detecting a driving mechanism for rotating the rotary shaft by supplying a current to said coil, said rotary shaft, a rotation angle from a reference position related to the rotation direction, the There is provided an oscillating reflector apparatus having a cooling means for introducing a gas into a casing and discharging the introduced gas to the outside of the casing after flowing through the drive mechanism .
[0006]
By cooling the inside of the housing, the temperature rise of the sensor can be suppressed. Thereby, the fall of the precision of the sensor resulting from a temperature rise can be prevented.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1A shows a cross-sectional view of an oscillating reflector device according to a first embodiment of the present invention. A sensor unit 20 is defined at one end of the cylindrical housing 1, and the other part is a drive unit 10. A rotating shaft 2 is inserted into the housing 1 along its central axis. The rotating shaft 2 passes through the sensor unit 20 and the driving unit 10 and is rotatably supported by rotating bearings 3 and 4. The rotary bearing 3 is attached to a partition that separates the drive unit 10 and the sensor unit 20. The other rotary bearing 4 is attached to the other end of the drive unit 10.
[0010]
An end of the rotating shaft 2 on the sensor unit 20 side protrudes to the outside of the housing 1, and a reflecting mirror 30 is attached to the tip thereof. The reflecting surface of the reflecting mirror 30 is parallel to the rotation center line of the rotating shaft 2. When the rotating shaft 2 rotates, the reflecting mirror 30 swings.
[0011]
A coil 12 is wound around the rotary shaft 2 in the drive unit 10. A permanent magnet 11 is mounted on the inner peripheral surface of the housing 1 with a gap from the coil 12. The rotating shaft 2 can be rotated by passing a current through the coil 12.
[0012]
The sensor unit 20 detects a rotation angle from a reference position with respect to the rotation direction of the rotation shaft 2. Hereinafter, the structure of the sensor 20 will be described. The sensor 20 includes a movable plate 21 and electrodes 22 and 23.
[0013]
FIG. 1B shows a front view when the movable plate 21 and the electrodes 22 and 23 are viewed in a line of sight parallel to the rotation axis 2. A movable plate 21 is attached to the rotary shaft 2 in the sensor unit 20. The movable plate 21 is configured by a pair of fan-shaped plates having a central angle of 90 ° with the rotational axis 2 as the center arranged at positions that are rotationally symmetric with respect to the rotational axis 2. The electrode 22 is disposed so as to face one surface of the movable plate 21, and the other electrode 23 is disposed so as to face the other surface. Each of the electrodes 22 and 23 is composed of a pair of fan-shaped plates having a central angle of 90 ° with the rotation axis 2 as the center, arranged at positions that are rotationally symmetric with respect to the rotation axis 2. Has been.
[0014]
When viewed in a line of sight parallel to the rotation axis 2, the electrode 22 substantially overlaps the other electrode 23. When the rotating shaft 2 rotates, the area of the overlapping portion between the electrode 22 and the movable plate 21 changes. When this area changes, the capacitance between the electrodes 22 and 23 changes. Information on the rotation angle from the reference position of the rotating shaft 2 can be obtained from the change in capacitance.
[0015]
A cooling pipe 40 is attached to a portion of the outer peripheral surface of the housing 1 that defines the drive unit 10. By flowing cooling water through the cooling pipe 40, the housing 1 and the inside thereof can be cooled. Note that the cooling pipe 40 may be extended to a portion that defines the sensor unit 20.
[0016]
When a current is passed through the coil 12, the coil 12 generates heat, and the temperature of the sensor unit 20 increases. When the temperature of the sensor unit 20 rises, the distance between the electrode 22 and the movable plate 21 and the distance between the electrode 23 and the movable plate 21 will fluctuate. When these distances change, the capacitance between the electrodes 22 and 23 changes, and the detection accuracy of the rotation angle of the rotary shaft 2 decreases.
[0017]
By flowing cooling water through the cooling pipe 40 to cool the housing 1 and the inside thereof, the temperature rise of the sensor unit 20 can be suppressed. Thereby, the fall of the detection accuracy of the rotation angle of the rotating shaft 2 can be prevented.
[0018]
FIG. 1C shows a sectional view of the oscillating reflector device according to the second embodiment. In the second embodiment, cooling fins 41 are mounted on the outer peripheral surface of the housing 1 in place of the cooling conduit 40 of the oscillating reflector device according to the first embodiment shown in FIG. ing. Other configurations are the same as those of the oscillating reflecting mirror of the first embodiment. The cooling fins 41 can efficiently dissipate heat generated from the coil 12 to the outside.
[0019]
FIG. 2A is a cross-sectional view of the oscillating reflector device according to the third embodiment. A gas inlet 45 and a gas outlet 46 are attached to the housing 1 instead of the cooling conduit 40 of the oscillating reflector device according to the first embodiment shown in FIG. Other configurations are the same as those of the oscillating reflecting mirror of the first embodiment.
[0020]
The gas inlet 45 is attached in the vicinity of one end of the driving unit 10, and the gas outlet 46 is attached in the vicinity of the other end of the driving unit 10. A cooling gas such as air is introduced into the housing 1 from the gas inlet 45. The gas introduced into the housing 1 cools the coil 12 and is discharged to the outside from the gas discharge port 46. The gas flows through the drive unit 10 in the housing 1, but does not flow through the sensor unit 20. For this reason, even when the gas flow rate is increased and the cooling capacity is increased, it is possible to prevent the detection accuracy from being lowered due to vibration of the sensor components in the sensor unit 20.
[0021]
FIG. 2B shows a sectional view of the oscillating reflector device according to the fourth embodiment. In the fourth embodiment, a gas inlet 47 and a gas outlet 48 are attached to the sensor unit 20 of the housing 1. A cooling gas is introduced into the sensor unit 20 from the gas introduction port 47, the inside of the sensor unit 20 is cooled, and is discharged to the outside through the gas discharge port 48.
[0022]
FIG. 2C shows a sectional view of the oscillating reflector device according to the fifth embodiment. In the fifth embodiment, a gas introduction port 49 is attached to the sensor unit 20 of the housing 1, and a gas exhaust port 50 is attached to the vicinity of the end of the drive unit 10 opposite to the sensor unit 20. Yes. A gas flow hole 51 is provided in the partition wall between the sensor unit 20 and the drive unit 10.
[0023]
A cooling gas is introduced into the sensor unit 20 from the gas inlet 47. The cooling gas introduced into the sensor unit 20 passes through the gas flow hole 51, cools the coil 12, and is discharged to the outside from the gas discharge port 50.
[0024]
In the third to fifth embodiments, at least one of the drive unit 10 and the sensor unit 20 is forcibly cooled by the cooling gas. For this reason, the influence by the heat_generation | fever from the coil 12 can be reduced, and the fall of the detection accuracy of a sensor can be prevented.
[0025]
FIG. 3A shows a sectional view of the oscillating reflector device according to the sixth embodiment. The drive unit 10, the sensor unit 20, and the reflecting mirror 30 have the same structure as that of the oscillating reflecting mirror device according to the first embodiment shown in FIG. In the sixth embodiment, a gas outlet 55 for blowing cooling gas to the reflecting mirror 30 is disposed. By blowing the cooling gas from the gas outlet 55 to the reflecting mirror 30, the temperature rise of the reflecting mirror 30 can be suppressed and thermal deformation can be prevented.
[0026]
FIG. 3B is a sectional view of the oscillating reflector device according to the seventh embodiment. A gas inlet 56 is provided in the sensor unit 20. A gap 57 is provided between an inner peripheral surface of a hole provided on the end surface of the housing 1 through which the rotary shaft 2 passes and an outer peripheral surface of the rotary shaft 2. Other configurations are the same as the structure of the oscillating reflector device according to the first embodiment shown in FIG. The cooling gas introduced into the sensor unit 20 from the gas introduction port 56 cools the inside of the sensor unit 20 and jets out through the gap 57 to the outside. The cooling gas ejected from the gap 57 cools the reflecting mirror 30. That is, the gap 57 acts as a gas outlet.
[0027]
FIG. 3C is a sectional view of the oscillating reflector device according to the eighth embodiment. A cooling fin 58 is attached to the surface of the reflecting mirror 30 opposite to the reflecting surface. Other configurations are the same as the structure of the oscillating reflector device according to the first embodiment shown in FIG. The cooling fins 58 can suppress the temperature rise of the reflecting mirror 30 and prevent thermal deformation.
[0028]
FIG. 4 shows a schematic diagram of a laser processing apparatus using the oscillating reflector apparatus according to the above embodiment. A laser light source 60 emits a processing laser beam. The laser beam emitted from the laser light source 60 is reflected by the reflecting mirror 61 </ b> A of the oscillating reflector device 61 and enters the reflecting mirror 62 </ b> A of the oscillating reflector device 62. The laser beam reflected by the reflecting mirror 62 </ b> A is converged by the fθ lens 63 and is incident on the workpiece 65 held on the XY table 64.
[0029]
The laser beam can be scanned in a two-dimensional direction by swinging the reflecting mirrors 61A and 62A. By controlling the rotation angles of the reflecting mirrors 61 </ b> A and 62 </ b> A, the laser beam can be incident on a desired position of the workpiece 65. If necessary, a field lens and a mask are arranged in the laser beam path.
[0030]
By using the oscillating reflector device according to the first to fifth embodiments, it is possible to prevent a decrease in the detection accuracy of the rotation angle due to a temperature rise of the sensor unit. Further, by using the oscillating reflecting mirror device according to the sixth to eighth embodiments, it is possible to prevent the deviation of the reflection direction of the laser beam due to the thermal deformation of the reflecting mirror.
[0031]
In addition, the combination of at least one of the cooling mechanisms according to the first to fifth embodiments and at least one of the cooling mechanisms according to the sixth to eighth embodiments reduces the detection accuracy of the sensor unit and the heat of the reflecting mirror. Deformation can be prevented. Thereby, the incident position of the laser beam can be controlled with high accuracy. Moreover, since an inexpensive electrostatic capacitance sensor can be used as the sensor, it is not necessary to use another expensive sensor that is not easily affected by temperature fluctuations.
[0032]
Hereinafter, the cooling effect of the oscillating reflector apparatus according to the above embodiment will be described. Consider a case in which a laser beam is incident on four apexes of a square having a side length of 50 mm in the laser processing apparatus shown in FIG. In the case of using the oscillating mirror device that is not equipped with a cooling mechanism, the length of one side of the square formed by the incidence of the laser beam was shortened by about 25 to 35 μm after one hour of continuous operation. On the other hand, when the oscillating reflector device according to the first embodiment was used, the amount of shortening of the length of one side of the square after one hour of continuous operation was at most about 5 μm. The flow rate of the cooling water was 10 liters / minute. Thus, sufficient effects can be obtained by cooling the oscillating reflector device.
[0033]
Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.
[0034]
【The invention's effect】
As described above, according to the present invention, by cooling the oscillating reflector device, it is possible to prevent a reduction in the accuracy of the rotation angle of the rotating shaft to which the reflector is attached.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a oscillating reflector device according to a first embodiment and a second embodiment of the present invention, and a front view of a sensor unit.
FIG. 2 is a sectional view of an oscillating reflector device according to third to fifth embodiments of the present invention.
FIG. 3 is a sectional view of an oscillating reflector device according to sixth to eighth embodiments of the present invention.
FIG. 4 is a schematic view of a laser processing apparatus using an oscillating reflector apparatus according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Housing | casing 2 Rotating shaft 3, 4 Rotating bearing 10 Drive part 11 Permanent magnet 12 Coil 20 Sensor part 21 Movable plate 22, 23 Electrode 30 Reflecting mirror 40 Cooling pipe line 41, 58 Cooling fins 45, 47, 49, 56 Gas Inlet 46, 48, 50 Gas outlet 51 Gas flow hole 55 Gas outlet 57 Gap 60 Laser light source 61, 62 Oscillating reflector device 63 fθ lens 64 XY stage 65 Workpiece

Claims (4)

A housing,
A rotating shaft that is rotatably supported in the housing and has at least one end protruding to the outside of the housing;
A reflecting mirror attached to the rotating shaft at a portion protruding to the outside of the housing and swinging by rotation of the rotating shaft;
The coil includes a coil wound around a portion of the rotating shaft in the casing, and a permanent magnet attached to the casing so as to be disposed with a first gap from the coil, and a current flows through the coil A drive mechanism for rotating the rotary shaft by
A sensor that detects a rotation angle of the rotation shaft from a reference position in a rotation direction;
An oscillating reflector apparatus comprising: a cooling unit that introduces gas into the housing, and after the introduced gas flows through the drive mechanism, discharges the gas out of the housing . The casing is provided with a hole through which the rotating shaft passes, a second gap is provided between the hole and the rotating shaft, and the gas introduced into the casing by the cooling means is The oscillating reflector device according to claim 1, wherein the oscillating reflector device is jetted out through the second gap to cool the reflector. The oscillating reflector device according to claim 1, wherein the sensor is disposed in the housing, and the cooling unit does not flow gas into a space in which the sensor is disposed. A housing,
  A rotating shaft that is rotatably supported in the housing and has at least one end protruding to the outside of the housing;
  A reflecting mirror attached to the rotating shaft at a portion protruding to the outside of the housing and swinging by rotation of the rotating shaft;
  A drive mechanism that is disposed within the housing and rotates the rotating shaft by passing an electric current;
  A sensor for detecting a rotation angle of the rotation shaft from a reference position with respect to a rotation direction based on a relative position between a movable member fixed to the rotation shaft in the housing and a fixed member fixed to the housing; ,
  A cooling means for passing a cooling gas through a space in which the movable member and the fixed member are arranged.
Have
  The casing is provided with a hole through which the rotary shaft passes, and a gap is provided between the hole and the rotary shaft, and the gas introduced into the space by the cooling means passes through the gap. A oscillating reflecting mirror device that cools the reflecting mirror through the outside.

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