JPH032393Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field of the Invention The present invention relates to a multi-point laser irradiation device for simultaneously performing soldering, etc. at multiple processing points using a laser beam. This relates to a multi-point laser irradiation device that can be adjusted independently.

Prior Art Conventionally, a device for soldering etc. using a laser oscillator is known, for example, from Japanese Patent Laid-Open No. 59-212184, but with this configuration, adjustment of the laser beam irradiation energy at the processing point is possible. , by detecting the temperature at the processing point and directly controlling the laser oscillator based on this.

By the way, in recent years, as a source of laser beams,
YAG (yttrium aluminum garnet) laser oscillators are often used. this
Since the YAG laser oscillator has a slow power response speed, it is difficult to accurately and quickly control the energy using the control method described above. Also,
As in the case of soldering an IC chip to a board,
When soldering is performed simultaneously at a plurality of processing points, it has been impossible to independently adjust the laser beam irradiation energy at each processing point.

Purpose of the invention Therefore, the purpose of the invention is to independently, accurately and quickly adjust the irradiation energy of a laser beam at each processing point in a multi-point laser irradiation device,
The purpose of the present invention is to enable the temperature at a processing point to be adjusted based on temporal change characteristics suitable for soldering and the like.

Summary of the invention In order to achieve the above object, the multi-point laser irradiation device of the invention includes a laser oscillator that outputs a laser beam and a splitting element that splits the laser beam from the laser oscillator into a plurality of laser beams. ,
An optical system that focuses the split laser beam on a predetermined processing point with a predetermined spot diameter, an aperture mechanism that partially and variably blocks the split beam, a temperature sensor that detects the temperature of the processing point, and a temperature sensor that detects the temperature of the processing point. It has a control device that controls the aperture mechanism based on the signal from the sensor and adjusts the irradiation energy of the laser beam as appropriate.By controlling the aperture mechanism with the control device, the laser beam can be irradiated without changing the spot diameter. By adjusting the irradiation energy of the beam, the aperture amount is changed in a follow-up manner so that the temperature at the processing point matches a preprogrammed temperature change characteristic over time.

Configuration of the Embodiment Hereinafter, the present invention will be specifically explained based on the embodiment shown in the drawings.

Figure 1 shows a multi-point laser irradiation device 1 according to the present invention.
The configuration is shown below.

This multi-point laser irradiation device 1 includes a laser oscillator 2
and a plurality of laser beams LB from the laser oscillator 2 (for example, four) laser beams LB1, LB2,
It is equipped with an optical dividing element 3 that divides into LB3 and LB4. Here, the laser oscillator 2 is, for example,
It is a YAG laser oscillator. In addition, the dividing element 3 is
In the illustrated case, there is a half mirror 3a that splits the laser beam LB from the laser oscillator 2 into a reflected laser beam LBa and a transmitted laser beam LBb, and a half mirror 3a that divides the laser beam LBa into two transmitted and reflected laser beams LB1 and LB2. Half mirror 3b to be divided
and a half mirror 3d that divides the transmitted laser beam LBb into two transmitted and reflected laser beams LB3 and LB4 via a total reflection mirror 3c,
Furthermore, it is comprised of total reflection mirrors 3e and 3f that reflect the laser beams LB2 and LB4 reflected by the half mirrors 3b and 3d and make them parallel to the laser beams LB1 and LB3.

An irradiation optical system 4 for converging each of the laser beams LB1 to LB4 onto a predetermined processing point S with a predetermined spot diameter is arranged in the optical path. Each optical system 4 has the same configuration, and only the optical system 4 is shown in detail in FIG.

In order to detect the temperature t of the processing point S irradiated by the laser beam LB1, a temperature sensor 5 is fixedly attached to the optical system 4, and detects a temperature signal T corresponding to the temperature t of the processing point S. Output. In addition, in front of optical system 4, there is a laser beam LB.
A throttle mechanism 6 that partially and variably blocks 1
is oblique to the optical axis of laser beam LB1,
For example, it is arranged integrally with the optical system 4 so as to form an angle of approximately 45 degrees.

This aperture mechanism 6 is constructed as shown in FIGS. 2A and 2B. That is, the cam plate 8, which is rotationally driven by the shaft 7a of the motor 7 fixed to the frame 6a, has a pair of cam surfaces 8 whose distance from the center of rotation decreases as the cam plate 8 rotates counterclockwise.
a, 8b. A pair of aperture blades 9 are movably supported by two guide shafts 10 that are parallel to each other and are biased toward the center by a spring (not shown), and pins 9a and 9b are fixed thereto. are in contact with the cam surfaces 8a, 8b of the cam plate 8, respectively, and follow the cam surfaces 8a, 8b when the cam plate 8 rotates. With this configuration, the pair of aperture blades 9 partially and variably block the laser beam LB1 according to the rotation of the motor 7. The tips of the diaphragm blades 9 are preferably formed in a chevron shape toward the center of the optical axis of the laser beam LB1, so that the spot diameter of the laser beam LB1 can be maintained constant while the motor 7 and the cam plate The rotation angle of 8 and the laser beam LB passing between the aperture blades 9
The irradiation energy of 1 is proportional to the irradiation energy of 1. This is because the density of the irradiation energy increases rapidly at the center of the laser beam spot, and by forming the aperture blades 9 in this shape, the irradiation of the laser beam spot at the processing point S is reduced. Energy density can be averaged.

The laser beam LB1 blocked and reflected by the aperture mechanism 6 is converted into a laser beam by the aperture mechanism 6.
Since it is arranged diagonally to the optical axis of LB1,
The light is emitted to the side of the optical system 4 and absorbed by the absorption plate 11 provided on the side.

It goes without saying that the optical system 4 is also provided with a temperature sensor, a diaphragm mechanism, and an absorption plate integrally with each other.

Next, FIG. 3 is a block diagram of the control device 12 of the multi-point laser irradiation device 1 according to the present invention. The signal generator 13 generates a target signal corresponding to a desired temporal change in the target temperature to at the processing point S during laser irradiation, based on a preset program.
Generate To. This characteristic is illustrated in FIG. The comparator 14 receives a signal T,To which is input from the temperature sensor 5 and the signal generator 13.
are compared, and the difference signal ΔT is output to the control circuit 15. The control circuit 15 receives the input difference signal ΔT
Based on this, the motor 7 is driven to rotate so that the difference signal ΔT becomes zero, the pair of aperture blades 9 are moved in the opening direction or the closing direction, and the irradiation energy of the laser beam LB1 is adjusted. The temperature t of S is set to a desired temperature to.

Effects of the Embodiment Next, the effects of the embodiment of the present invention configured as described above will be explained.

First, the multi-point laser irradiation device 1 is positioned above the workpiece to be processed such as soldering, and each laser beam LB1 to LB4 is applied to the processing point S.
so that each converges at a predetermined spot diameter,
Adjustments are made by moving each optical system 4 along the optical axis by an adjustment mechanism (not shown), or by moving only a part of each optical system, for example, one concave lens. The aperture blades 9 of each aperture mechanism 6 are closed so that the laser beam does not pass therethrough. From this state, the laser color generator 2 is activated to generate a laser beam of appropriate power.
When LB is output and each control device 12 is operated at the same time, the control circuit 15 controls the motor 7 based on the difference signal ΔT in response to the signal T from the temperature sensor 5 and the signal To from the signal generator 13. The laser beams LB1 to LB1 are rotated in the direction of eliminating the deviation, and the aperture blades 9 are thereby moved closer to or farther apart from each other, and the laser beams LB1 to LB1 passing between the aperture blades 9 are rotated.
Each irradiation energy of LB4 is adjusted, and each processing point S has an optimum temperature to. At this time, the laser beams reflected by the aperture blades 9 of the aperture mechanism 6 are emitted to the sides, and the absorption plate 1
1, it does not adversely affect the control of irradiation energy at each processing point.

Effects of the invention As described above, according to the invention, a multi-point laser irradiation device is provided with an aperture mechanism that partially and variably blocks the divided laser beam irradiated to each processing point. Since the temperature of the processing point is adjusted to the desired temperature according to the signal from the temperature sensor that detects the temperature of the processing point, the irradiation energy is adjusted by the aperture mechanism, which reduces the slow power response speed. Even when a YAG laser oscillator is used, the irradiation energy can be adjusted accurately and quickly, and the irradiation energy at each processing point can be adjusted independently according to the temperature characteristics of each processing point. Further, based on a preset program, the temperature at the processing point can be continuously controlled without changing the intensity of the laser power according to a desired temporal change that is optimal for soldering or the like.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the optical configuration of a multi-point laser irradiation device according to the present invention, Fig. 2 shows a specific example of the configuration of the aperture mechanism of the embodiment shown in Fig. 1, and Fig. A is a sectional view thereof. , Figure B is a plan view of the cam plate, Figure 3 is a block diagram showing the configuration of the control device of the embodiment shown in Figure 1, and Figure 4 shows the temperature at the processing point according to a program preset in the signal generator. It is a program graph which shows an example of the temporal change of t. 1... Multi-point laser irradiation device, 2... Laser oscillator, 3... Division element, 4... Optical system for irradiation, 5
... Temperature sensor, 6 ... Aperture mechanism, 7 ... Motor, 8 ... Cam plate, 9 ... Aperture blade, 12 ... Control device.

Claims (1)

[Claims for Utility Model Registration] (1) A laser oscillator that outputs a laser beam, a dividing element that divides the laser beam from the laser oscillator into a plurality of laser beams, and directs each divided laser beam to a predetermined processing point. an optical system that converges to a predetermined spot diameter; an aperture mechanism that partially and variably blocks the divided laser beam;
It has a temperature sensor that detects the temperature of the processing point, and a control device that controls the aperture mechanism based on a signal from the temperature sensor to adjust the irradiation energy of the laser beam as appropriate, and the control device controls the aperture mechanism. By controlling the temperature of the processing point, the irradiation energy of the laser beam can be adjusted without changing the spot diameter, and the temperature of the processing point can be individually changed to match the temporal change in temperature programmed in advance. Point laser irradiation device. (2) The multi-point laser irradiation device according to claim 1, wherein the aperture mechanism is arranged obliquely to the optical axis of the laser beam. (3) The diaphragm mechanism includes diaphragm blades that are supported so as to be movable toward or away from each other and whose tips can partially block the laser beam, and a drive means for moving the diaphragm blades back and forth. A multi-point laser irradiation device according to claim 1 or 2, characterized in that the device is comprised of: (4) The multi-point laser irradiation device according to claim 3, wherein the tips of the aperture blades are formed in a mountain shape toward the center of the optical axis of the laser beam.