JP2001047267A - Method for detecting laser beam and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for detecting a laser beam wide in the range of beam energy to be detected and inexpensive, and a device therefor. SOLUTION: A pulse distributor 11 is arranged in an optical path of a laser beam 6 outputted in a pulse state from a laser oscillator 5. Then, during either of or both of the periods from the starting of output of the laser beam 6 to the starting of working or from the finish of working to the decay of the laser beam 6, the laser beam 6 is deflected to the side of an absorption plate 24, by which major part of the beam energy is absorbed and changed into heat. A part of the laser beam 6 reflected by the absorption plate 24 is detected by an optical sensor 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam detecting method and a laser beam detecting device used in a laser beam machine for checking whether or not a laser beam has actually been output.

[0002]

2. Description of the Related Art For example, in the case of a laser drilling machine that drills a printed circuit board with a laser beam, one hole is processed by irradiating a pulsed laser beam having a short irradiation time one to several times. If laser light is not output for some reason, processing failure occurs. Therefore, processing is performed while confirming that the laser light has been irradiated by the laser light detection device.

FIG. 6 is a configuration diagram of a conventional laser light detecting device. In the figure, reference numeral 1 denotes a laser beam detecting device, 2 denotes a beam splitter, 3 denotes an attenuation filter, and 4 denotes an optical sensor. Reference numeral 5 denotes a laser oscillator, which outputs a laser beam 6.

Next, the operation of the above-described conventional laser light detecting device 1 will be described. The laser beam detector 1 is arranged so that the beam splitter 2 is aligned with the optical path of the laser beam 6. The laser light 6 output from the laser oscillator 5 is applied to the beam splitter 2
Part (approximately 0.1%) of the light is reflected by the incident portion, and the power is reduced by the attenuation filter 3 and is incident on the optical sensor 4.
The optical sensor 4 outputs a detection signal when detecting the laser beam 6. The laser drilling machine checks the presence or absence of a detection signal output from the optical sensor 4 every time the laser oscillator 5 outputs the laser beam 6, and if the detection signal is output, continues the operation, and If not output, stop the operation. As a result, processing defects could be prevented.

[0005]

By the way, the optical sensor 4
Is broken when a laser beam 6 having a large energy per unit time (hereinafter referred to as beam energy) is incident.
On the other hand, the amount of the laser beam 6 reflected at the entrance of the beam splitter 2 is proportional to the amount of the laser beam 6 incident on the beam splitter 2.
Therefore, even when the beam energy is maximized, it is necessary to select the attenuation rate of the attenuation filter 3 so that the laser light 6 incident on the optical sensor 4 becomes equal to or less than the allowable value of the optical sensor 4. For this reason, when processing is performed with a reduced beam energy, it is difficult to detect the laser beam 6. Further, the beam splitter and the attenuation filter are expensive.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art, and to provide a wide range of detectable beam energies.
Another object of the present invention is to provide an inexpensive laser beam detection method and a laser beam detection device.

[0007]

According to a first aspect of the present invention, an optical path refracting means for refracting an optical path of a laser beam is disposed in the optical path of the laser light. In the laser processing method in which the laser energy input to the processing unit is controlled, the output of the laser light to the processing unit is confirmed by detecting the presence or absence of laser light during a period not used for processing.

According to a third aspect of the present invention, there is provided a switching device which is disposed in an optical path of a laser beam output from a laser oscillator and switches the optical path of the laser beam between a straight traveling direction and a refracting direction. It is characterized by comprising a control device for determining a period, and a detection device for detecting either one of the laser light in the refraction direction or the laser light in the straight direction output from the switching device.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a configuration diagram of a laser beam detection device according to the present invention, FIG. 2 is a plan view of a detection unit, FIG. 3 is a side view of FIG. 2, and components having the same functions or functions as those in FIG. And the description is omitted. In the figure, reference numeral 10 denotes a laser beam detecting device. Reference numeral 11 denotes a pulse distributor, which is arranged in the optical path of the laser light 6. The pulse distributor 11 can refract the laser beam 6 by a predetermined angle (bend the optical path) with respect to the straight traveling direction by applying ultrasonic waves to germanium inside. Reference numeral 12 denotes a control device, which is a pulse distributor 1
1 is controlled. The control device 12 is connected to a control device of a laser drilling machine (not shown).

Reference numeral 21 denotes a support block, in which a cooling water passage 22 is formed. 23 is a joint for cooling water passage 2
2 are connected to both sides. 24 is an absorption plate,
It is fixed to the side surface of the support block 21 by a bolt 25. When the laser beam 6 is a laser beam having a wavelength of 9.3 or 10.6 μm output from a carbon dioxide laser oscillator, the absorption plate 24 is provided with a surface having a high absorptance (small reflectance) of the laser beam 6. It is formed of an iron plate, an aluminum plate, ceramic, or the like that has been subjected to iron treatment. Reference numeral 26 denotes a support, which is fixed to a side surface of the support block 21 by a bolt 25. A holder 27 is fixed to the support 26 and holds the optical sensor 4.

Next, the operation of this embodiment will be described. The laser beam 6 is a carbon dioxide laser. The absorption plate 24 is an iron plate whose surface has been treated with triiron tetroxide, and the surface has fine irregularities. When the pulse distributor 11 receives the straight-ahead command from the control device 12, the pulse distributor 11 causes the laser beam 6 to go straight while receiving the command, and otherwise refracts the laser beam 6 toward the absorption plate 24 side. The laser beam 6 that has traveled straight forms a hole in the printed circuit board. Also, the light is refracted and the absorption plate 24
Most of the laser light 6 that has arrived at is absorbed by the absorption plate 24 and converted into heat, and a part (about 1%) of the laser light 6 is absorbed.
4 is diffusely reflected on the surface of
Sensor at a distance of (hereinafter referred to as optical sensor)
4 is incident. When the optical sensor 4 detects the laser beam 6 reflected by the absorbing plate 24, it outputs a detection signal. The laser drilling machine checks the presence or absence of a detection signal output from the optical sensor 4 every time the laser oscillator 6 outputs the laser light 6,
When the detection signal is output, the operation is continued, and when the detection signal is not output, the operation is stopped.

Next, the detection period in the present embodiment will be further described. FIG. 4 is a diagram showing a relationship between beam energy P and time according to the present embodiment. The laser light 6 is output for a period T2 every period T1 (in the case of FIG.
Times). In the period T2, the beam energy P gradually increases and becomes a constant value. The controller 12 first instructs the laser oscillator 5 to start outputting and turns on the sensor 4 (time h1, h2, h3 in the figure). And period T
When c elapses (at times s1, s2, and s3 in the figure, the beam energy P reaches a predetermined value Pk), a straight-forward command is output to the pulse distributor 11 and the sensor 4 is turned off. . Then, when the period Tk elapses (time e1, e2, e3 in the figure), the straight traveling command to the pulse distributor 11 is released, and the laser oscillator 5 is instructed to stop the output.

In the above embodiment, substantially uniform beam energy having a size equal to or larger than Pk can be used for processing, and the processing quality can be made uniform. Also,
Since the period Tc that is not suitable for processing in which the beam energy P gradually increases is set as the detection period, the processing energy is not reduced. Moreover, when the amount of processing energy is controlled in the period Tk, the beam energy period Tc is substantially constant, so that the presence or absence of laser beam irradiation can be reliably detected.

Further, since the laser light 6 is irregularly reflected on the surface of the absorption plate 24, the amount of energy incident on the optical sensor 4 can be easily adjusted by changing the distance L, and the adjustment range can be adjusted. Can also be large.

Further, since the laser beam 6 is absorbed by the absorption plate 24, most of the beam energy P is converted into heat and cooled through the support block 21, so that the absorption plate 24 is cooled.
Will not be damaged by heating. Therefore, maintenance is easy and the configuration of the damping device is simple.

FIG. 5 is an explanatory diagram of a laser beam detection period showing another embodiment according to the present invention. The laser beam 6 is in the period T
The period T3 is output every one (three times in the case shown). In the period T3, the beam energy P rapidly increases to a constant value. The control device 12 firstly controls the laser oscillator 5
And the sensor 4 is turned on (time h11, h21, h31 in the figure). And the period Tc
When 1 elapses (time s11, s21, s31 in the figure.
When processing is started at a time when a predetermined time has elapsed since the beam energy P became a predetermined value. ), A straight-ahead command is output to the pulse distributor 11, and the sensor 4 is turned off. Then, when the period Tk elapses (time e11,
e21, e31) Release the straight traveling command to the pulse distributor 11, and instruct the laser oscillator 5 to stop the output.

This embodiment is suitable for the case where the rise of the beam energy P is fast, etc., and when the single irradiation period T3 of the laser beam 6 output from the laser oscillator 5 is changed, the detection period Tc1 is the same. By doing so, it is not necessary to adjust the incident amount of the laser light 6 incident on the optical sensor 4. When increasing the beam energy P, the period Tc1 may be shortened.

In the above description, the case where the laser beam is pulsed has been described. However, it is needless to say that the present invention can be applied to a case where the irradiation time is long.

Further, in the above, the optical sensor 4 is set to the period Tc.
1 is turned on, but if the laser light 6 is also turned on during a period in which the laser light 6 is attenuated (for example, a period from time e1 to time f1 in FIG. 4), the output of the laser light 6 before and after processing is reduced. As a result, the output of the laser beam 6 can be confirmed more reliably.

Note that only during the period when the laser beam 6 is attenuated,
The optical sensor 4 may be turned on.

In the above description, an infrared sensor is used as the optical sensor, but another optical sensor may be used.

Further, the pulse distributor 11 is designed to make the laser beam 6 go straight while receiving the rectilinear command, and refract the laser beam 6 in other cases. May be refracted, and in other cases, the laser beam 6 may travel straight.

[0023]

As described above, according to the present invention,
In a laser processing method in which an optical path refracting means capable of refracting an optical path of a laser beam is disposed in an optical path of a laser beam, and the laser energy input to a processing unit is controlled by the optical path refracting means, a period during which the laser beam is not used for processing Since the output of the laser beam to the processing portion is confirmed by detecting the presence or absence of the laser beam, the range of the beam energy that can be detected is wide. In addition, even if the beam energy used for processing changes, the energy at the time of detection does not change, so that the detection accuracy is stable and the laser beam can be reliably detected. Further, since the absorbing plate is employed as a means for attenuating the energy incident on the optical sensor, the configuration is simple and the maintenance period can be extended.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a laser light detection device according to the present invention.

FIG. 2 is a front view of a detection unit of the laser light detection device according to the present invention.

FIG. 3 is a plan view of FIG. 2;

FIG. 4 is a diagram showing a relationship between beam energy P and time according to the present embodiment.

FIG. 5 is an explanatory diagram of a laser beam detection period showing another embodiment according to the present invention.

FIG. 6 is a configuration diagram of a conventional laser light detection device.

[Explanation of symbols]

 Reference Signs List 4 optical sensor 5 laser oscillator 6 laser beam 11 pulse distributor 12 control device 24 absorption plate

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kunio Arai 2100 Kamiimaizumi, Ebina-shi, Kanagawa F-term in Hitachi Biomechanics Co., Ltd. 2G065 AB02 AB09 AB14 AB22 BA14 BB14 BB24 BC19 BC21 CA16 4E068 CA18 CB08 CB09 CC01 CF04

Claims (4)

[Claims] 1. A laser processing method comprising: disposing an optical path refracting means capable of refracting an optical path of a laser beam in an optical path of a laser beam; and controlling laser energy input to a processing unit by the optical path refracting means. A method for detecting laser light, comprising: confirming the output of laser light to a processing part by detecting the presence or absence of laser light during a period not used for processing. 2. The method according to claim 1, wherein the period not used for the processing is at least one of a period from the start of the output of the laser beam to the start of the processing or a period from the end of the processing to a period in which the laser light is attenuated. The method for detecting a laser beam according to the above. 3. A switching device disposed in an optical path of laser light output from a laser oscillator, for switching the optical path of the laser light between a straight traveling direction and a refracting direction, and a control device for determining a switching period of the switching device; A detecting device for detecting one of a laser beam in a refraction direction and a laser beam in a straight traveling direction output from the switching device. 4. The laser beam detecting apparatus according to claim 3, wherein the start of the switching period for switching to the refraction direction is the start of the output of the laser beam, and the end thereof is the start of machining. .