JPH11312831A - Laser beam leakage detecting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam leakage detecting system, wherein the operating conditions of each part of a laser device are self-diagnosed, so that only when desired is the laser light surely prevented from leaking outside the laser device, for operation safety such as laser working and laser welding. SOLUTION: For a laser beam leakage detecting system in which the leakage of laser beam from a laser device incorporating a laser beam source 10 is detected, between the laser beam source 10 and a coupling optical system 30 for guiding the laser beam to outside the laser device, a shutter 20 for shielding the laser beam, a shutter sensor 100 for detecting open/close state of the shutter 20, a scatter sensor 110 for detecting a part of the laser beam scattered with the coupling optical system 30, and a warning signal generating means 141 for warning laser beam leakage are provided. Here, based on a shutter drive signal C, a shutter sensor signal b, and a scatter sensor signal a, a warning signal generating means 141 is driven.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser apparatus for performing processing, welding, and the like by using a laser beam.
The present invention relates to a laser beam leak detection system that performs processing such as detecting and issuing an alarm in order to ensure the safety of an operator when leaking out of the laser device when unnecessary.

[0002]

2. Description of the Related Art Conventionally, there are a laser processing machine and a laser welding machine which irradiate a high-power laser beam for processing and welding of parts and the like.

FIG. 4 shows, as an example, a laser beam machine that guides a YAG laser to a welding site by an optical fiber. According to FIG. 4, a laser beam having an oscillation wavelength of 1.0641 μm and a wavelength of about several hundred watts to several kilowatts is irradiated with a core diameter of 0.4
energy transmission from 0.8 mm to 0.8 mm optical fiber,
Laser processing is performed by forming a laser beam into a fine spot using a processing condensing lens at the emission end of the optical fiber, and dissolving or drilling a surface of a component or the like. When comparing a laser beam machine and a laser welding machine, the laser light source and the energy transmission optical system have many commonalities, and the differences are found only in the points such as the scanning of the laser beam and the method of placing parts and the like. Absent.

[0004] When processing or the like is completed by the above-described laser processing machine or the like, a shutter is used to prevent laser light from being emitted from the laser processing machine or the like.

[0005]

However, if the shutter malfunctions and the laser beam is kept leaking out of the laser device such as a laser beam machine or a laser welding machine, the finished product is damaged. Or even a fire may occur. Further, many of the wavelengths of the high-power laser light used in the above-described laser device are in the infrared region and are invisible, which is dangerous for the operator.

In such a case, it is conceivable to issue an alarm by operating an alarm or the like. However, if the operation is performed based on the alarm warning and the alarm does not sound due to a malfunction, the above-mentioned danger is rather raised. Will be larger.

Further, if the shutter is operated in conjunction with the alarm operation, safety is ensured. However, when the shutter malfunctions and the laser beam remains leaking out of the laser device, the laser oscillation must be stopped. However, conversely, if laser oscillation is stopped in spite of no leakage of laser light, processing work and the like will be hindered. Also, once the laser oscillation is stopped, it takes time until the laser oscillation is stabilized even if the power is turned on again.

Accordingly, the present invention provides a self-diagnosis of the operation state of each part of the laser device, and reliably prevents the laser light from leaking out of the laser device only when desired, and performs the work such as laser processing and laser welding. It is an object of the present invention to provide a laser beam leak detection system which ensures the safety of a laser beam.

[0009]

A laser beam leak detection system according to the present invention for solving the above-mentioned problem is a laser beam leak detection system for detecting a laser beam leak from a laser device having a built-in laser light source. A shutter that blocks the laser beam between the laser light source and a coupling optical system that guides the laser beam to the outside of the laser device, a shutter sensor that detects an open / closed state of the shutter, and scattering by the coupling optical system. A scattering sensor for detecting a part of the laser beam, and a warning signal generating unit for warning the laser beam leakage, based on the shutter drive signal, the shutter sensor signal, and the scattering sensor signal, The warning signal generating means is driven.

That is, in the system of the present invention, the laser beam leakage is directly confirmed by detecting the weak scattered light scattered by the energy transmission optical system for guiding the laser light out of the laser device. After self-diagnosis of the operation status of the laser device, an alarm is activated only when desired.

According to another aspect of the present invention, there is provided a laser beam detecting device for shutting off a laser beam, a shutter sensor for detecting an open / closed state of the shutter, and a part of the laser beam. The scattering sensor includes a hollow member, an optical fiber connected to the hollow member, and a photoelectric conversion element connected to the optical fiber.

That is, in the apparatus of the present invention, the optical system for detecting the scattered laser beam is made independent as an integral unit.

[0013] A laser beam leak detection method according to the present invention is a laser beam leak detection method for detecting laser beam leak from a laser device incorporating a laser light source.
In order to prevent the laser beam emitted from the laser light source from being emitted to the outside of the laser device, the shutter is driven, and the shutter drive signal for detecting the open / closed state of the shutter and closing the shutter is transmitted. Determining whether or not the shutter is closed, and determining whether or not the laser beam is scattered from an optical system for outputting the laser beam to the outside of the laser device. A warning signal is generated when the shutter drive signal indicates a closed state, and when the shutter is in the closed state and the laser beam is scattered. Like that.

That is, in the method of the present invention, a step of judging the operation status of the laser device based on a signal indicating the operation status of each part of the laser device is executed, and only when desired, a warning by an alarm or a stop of laser oscillation is made. It is carried out.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the system of the present invention. As shown in FIG. 1, a laser beam 11 output from a laser light source 10 enters a coupling optical system 30 as a laser beam 12 via a shutter 20, and exits from an exit end of the coupling optical system 30 as a laser beam 13.
Then, the laser beam 13 propagates through the core of the optical fiber 40, becomes a minute spot by the focusing optical system 50, and is imaged on the objects 70 and 71 such as processing and welding.

In the laser device having the above configuration,
In order to determine whether or not the laser beam 11 is output outside the laser device, in the present invention, the coupling optical system 30 is used.
The laser light 14 scattered by is detected.
Here, the scattering of the laser beam by the coupling optical system 30 is scattering caused by slight irregularities on the surface of the optical element, and is scattered as weak light in a direction off the optical axis. A part of the laser light 14 thus scattered is introduced into the optical fiber 112 and photoelectrically converted by the photodetector 111.

In order to detect whether or not the laser beam 11 output from the laser light source 10 is output to the outside of the laser device, in other words, whether or not there is laser beam leakage, the present invention employs a photodetector. In addition to the scattering signal a, which is the photoelectric conversion output signal of 111, a shutter sensor signal b for detecting the open / closed state of the shutter 20 and a shutter drive signal c for opening and closing the shutter 20 are used.

That is, the system of the present invention shown in FIG.
In order to determine whether or not there is a laser leak, the sensor controller 130, shutter controller 140, warning signal controller 150, laser controller 160, and input means 170 are each connected to a central processing unit (CPU).
180 or these controllers are connected to each other.

The configuration of the system of the present invention is as described above. Therefore, each component of the system of the present invention will be described next.

The laser light source 10 extracts laser light from the resonator by means of a Q switch, ultraviolet excitation, or the like. For example, a YAG laser, a carbon dioxide laser, or the like is preferable.

The shutter 20 is a mechanical component that blocks the optical path of the laser beam, and may be, for example, that the reflecting mirror is rotated by a solenoid.

The coupling optical system 30 is generally a lens system. However, as shown in FIG. 1, when energy transmission is performed by an optical fiber, a single convex lens may be sufficient.

The optical fiber 40 is an optical fiber having a high damage threshold due to a high-energy laser beam, a protective film having a finished end face, and a high transmittance. For example, a multimode glass fiber for optical communication is suitable.

The focusing optical system 50 is also generally a lens system. However, as shown in FIG. 1, when energy transmission is performed by an optical fiber, a single convex lens may be sufficient. In particular, in the case of laser processing or laser trimming using a minute spot having a diameter of about several μm, an optical system including an objective lens from which aberration has been removed is required.

The shutter sensor 100 includes a shutter 20,
That is, for example, a sensor capable of detecting the position of the reflecting mirror occupying two different positions due to rotation or the like, for example, a photo interrupter is preferable.

The scattering sensor 110 includes a light detector 111
, An optical fiber 112 and a hollow body 113.

Here, the photodetector 111 is obtained by connecting a photoelectric conversion element sensitive to a laser wavelength to an amplifier having a high gain. For example, the wavelength of a YAG laser is 1.06 μm.
For a laser beam of m, a Ge photodiode is connected to an operational amplifier. Here, the gain of the operational amplifier is set according to the intensity of the scattered light.

The optical fiber 112 is a light guide for guiding the weak laser light scattered by the coupling optical system to the photodetector 111. Since the transmission distance is about several centimeters, the optical fiber 112 itself has high quality. No need. However, the core diameter is determined in consideration of the intensity ratio between the stray light inside the laser device and the scattered light.

The hollow body 113 is connected to the optical fiber 112 so that only a specific small angle portion of the scattered light 14 is made incident on the optical fiber 112. This hollow body 113
Is, for example, a hollow rod or square rod made of Al or the like along its axis.

The sensor controller 130 calculates the scattering signal a
And a shutter sensor signal b and a shutter drive signal c, and relay these signals to C
It is an electronic circuit that sends the command signal d to the PU 180 or controls the shutter controller 130, the warning signal controller 140, and the laser controller 150, which will be described later.

The shutter controller 130 is an electronic circuit that outputs a shutter drive signal c in accordance with an instruction from the sensor controller 120 or an instruction from a CPU 170 described later.

The warning signal controller 140 is an electronic circuit that drives the warning signal generating means 141 according to an instruction from the sensor controller 120 or a CPU 170 described later. Here, the alarm signal generating means 141 is preferably an alarm, but may be a lamp or a display.

The laser controller 170 is an electronic circuit for turning on / off the power supply of the laser light source 10 according to an instruction from the sensor controller 140 or a CPU 170 described later.

The input means 160 is a means for inputting a processing pattern, a welding position, other work procedures, and the like to a CPU 170 described later, and uses a keyboard, a mouse, a light pen, and the like.

The components of the system according to the present invention have been described above with reference to FIG.

One of the features of the system of the present invention is that, as described above, the detection of the laser beam 14 scattered by the coupling optical system 30 directly detects laser beam leakage to the outside of the laser device. It is in.

FIG. 2 is a plan view of a laser beam detecting apparatus having such features and particularly suitable for implementing the present invention.

As shown in FIG. 2, this laser beam detecting device comprises coupling optical systems 30a and 30b, a photodetector 111
a and 111b, optical fibers 112a and 112b, hollow bodies 113a and 113b, shutters 20a and 20b, and shutter sensors 100a and 100b are integrated into one housing. The structure and function of each of these components are the same as those described in the description of FIG. Note that FIG.
The reason why the two sets of coupling optical systems 30a, 30b, etc. are provided is to allow two places to be processed and welded at the same time.

In the laser beam detector shown in FIG. 2, a high-energy laser beam for processing / welding, etc.
For example, the YAG laser beam 11 is reflected by the reflecting mirror B and split into two by the semi-transparent mirror C. Then, the YAG laser beam 11 transmitted through the semi-transparent mirror C is guided to the coupling optical system 30a. On the other hand, the YAG laser beam 1 reflected by the semi-transparent mirror C
1 is reflected by the reflecting mirror D and guided to the coupling optical system 30b. In order to adjust the optical axis of such an optical system, a visible laser beam, for example, a HeNe laser beam 19 is coupled to the YAG laser beam by the reflecting mirror A.

The configuration of the system of the present invention has been described above with reference to FIGS.

Next, the operation of the system of the present invention will be described with reference to FIGS.

In the system of the present invention, the laser beam leakage is directly confirmed by detecting the weak scattered light scattered by the energy transmission optical system for guiding the laser light to the outside of the laser device, and the operating condition of the laser device is confirmed. Is self-diagnosed, and a warning by an alarm and a stop of laser oscillation are performed only when desired.

That is, the sensor controller 120 which has received the shutter drive signal c, the shutter sensor signal b, and the scattering sensor signal a self-diagnoses the operation state of the laser device from the three signals, and controls the shutter controller 130 which drives the shutter. Then, the control signal d is sent to the warning controller 140 for driving the warning signal generating means 141 and the laser controller 150 for driving the laser light source 10.

Here, the contents of the self-diagnosis
Is programmed in the sensor controller,
For example, the shutter sensor signal b indicates that the shutter is open, and the scattering sensor signal a indicates that the shutter drive signal c indicates that the shutter is closed and the laser beam 11 is shut off, even though the shutter drive signal c indicates that the shutter is closed. If it indicates that the scattered light has been detected, the control signal d is sent to the warning signal controller 140, or the like.

In the above description of the system of the present invention, system control is performed by incorporating a program in the sensor controller 120. Instead, a central processing unit (CPU) 170 is provided to control the system. You may.

When the CPU 170 is provided, this CP
U170 receives the input of the three signals of the scattering sensor signal a, the shutter sensor signal b, and the shutter drive signal c from the sensor controller 120 and the input of the procedure such as machining and welding from the input means 160, and receives these inputs. Is processed by the program as described above, and the shutter controller 13
0, warning signal controller 140, laser input means 16
Send a control signal to 0.

Therefore, when the CPU 170 is used, the input means 160 is used for the self-diagnosis of the operation state of the laser device.
Since the information from is also added, a warning can be issued more accurately.

In particular, when using the laser beam detecting device of FIG. 2 integrated with the housing, the shutter 20a,
20b, two independent shutter drive signals are sent out,
The two-system shutter drive signal and the shutter sensor 100
a, 100b, and two systems of scatter sensor signals from the photodetectors 111a, 111b are input to the sensor controller 120.

The operation of the system according to the present invention has been described above with reference to FIGS.

Next, the method of the present invention will be described with reference to FIGS.

FIG. 3 is a flowchart for executing the laser beam leak detection method of the present invention. In the method of the present invention, the step of determining the operation status of the laser device is performed based on a signal indicating the operation status of each section of the laser device, and a warning by an alarm and a stop of laser oscillation are performed only when desired.

As shown in FIG. 3, first, in step S10
Now, a shutter drive signal c for closing the shutter 20
It is a step of determining whether or not is transmitted. Here, if the shutter drive signal c for closing the shutter 20 has been transmitted, the process proceeds to step S20, but if not, the process proceeds to step S11. In step S11, if the shutter is open in the light of the input condition, the process ends. However, immediately after that, immediately start the procedure shown in this flowchart,
Self-diagnosis of the operation status of the laser device. On the other hand, if it is determined in step S11 that the shutter should not be open in the light of the input condition, the process proceeds to step S12,
A shutter drive signal c is sent to close the shutter 20.

Next, proceeding from step 10 to step 20, step S20 is a step for determining whether or not the shutter sensor 100 has detected that the shutter 20 is in the closed state. Here, if shutter 2
If it is found that 0 is not in the closed state, the processing is stopped. However, immediately thereafter, the procedure shown in this flowchart is started, and the operating status of the laser device is always self-diagnosed.

Next, when the process proceeds from step 20 to step 30, step 30 is a step for determining whether or not the scattering sensor 110 has detected scattered light. Here, if
If no scattered light has been detected, the process ends. However, immediately thereafter, the procedure shown in this flowchart is started, and the operating status of the laser device is always self-diagnosed.

Next, when the process proceeds from step 30 to step 40, step 40 is a step for generating a warning signal 1 such as an alarm.
This is a step of driving the reference numeral 41.

Then, the process proceeds to step S50 following the process of step S40.

In step S50, it is dangerous if the alarm or the like continues to ring, so it is determined whether or not a predetermined time has elapsed since the alarm or the like was driven. here,
If a predetermined time has elapsed, the laser beam of the laser light source 10 is stopped to ensure safety. On the other hand, if the predetermined time has not elapsed, the process returns to step S10 to check the shutter drive signal.

[0059]

As described above, according to the present invention,
The self-diagnosis of the operation status of each part of the laser device can prevent the laser beam from leaking out of the laser device only when desired, thereby ensuring the safety of operations such as laser processing and laser welding.

Specifically, first, it is possible to reliably warn of laser beam leakage and stop laser oscillation only when desired, without being misled by a shutter failure or the like.

Secondly, since the operation status of the laser writing is self-diagnosed with reference to the procedures of laser processing and welding, etc.,
The laser device can be operated more appropriately and safely.

Third, it is possible to provide a compact device capable of directly detecting laser beam leakage. This device can be attached to a small wand at a desired position inside or outside a laser device such as an existing laser processing machine or laser welding machine.

Fourth, since the self-diagnosis of the operating condition of the laser device can be made comprehensively based on sensor signals and the like, the laser device can be safely operated.

[Brief description of the drawings]

FIG. 1 is a plan view of a laser beam leak detection device according to the present invention.

FIG. 2 is a block diagram of a laser beam leak detection system according to the present invention.

FIG. 3 is a flowchart of a laser beam leak detection method of the present invention.

FIG. 4 is a conceptual diagram of a conventional laser beam machine. Circuit showing the input and output of the adder.

[Explanation of symbols]

 Reference Signs List 10 laser light source 20 shutter 30 coupling optical system 40 optical fiber 100 shutter sensor 110 scattering sensor shutter sensor 120 sensor controller 130 shutter controller 140 warning signal controller 150 laser controller 160 input means 170 CPU

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G01M 11/00 G01M 11/00 U

Claims (7)

[Claims] 1. A laser beam leak detection system for detecting a laser beam leak from a laser device having a built-in laser light source, wherein the laser beam leak detection system is provided between the laser light source and a coupling optical system for guiding the laser beam to the outside of the laser device. A shutter for blocking the laser beam, a shutter sensor for detecting an open / closed state of the shutter, a scattering sensor for detecting a part of the laser beam scattered by the coupling optical system, and a warning of the laser beam leakage. A laser beam leakage detection system, comprising: a warning signal generating unit, wherein the warning signal generating unit is driven based on a shutter driving signal, a shutter sensor signal, and a scattering sensor signal. 2. The laser according to claim 1, wherein the scattering sensor includes a hollow member, an optical fiber connected to the hollow member, and a photoelectric conversion element connected to the optical fiber. Beam leak detection system. 3. A sensor controller that receives the shutter drive signal, the shutter sensor signal, and the scattering sensor signal, a shutter controller that drives the shutter, a warning controller that drives the warning signal generation unit, and the laser. The laser beam leakage detection system according to claim 1, further comprising a laser controller that drives a light source, wherein the sensor controller drives at least one of the shutter controller, the warning controller, and the laser controller. 4. A sensor controller for receiving the shutter drive signal, the shutter sensor signal, and the scatter sensor signal, a shutter controller for driving the shutter, a warning controller for driving the warning signal generating means, and the laser. A laser controller that drives a light source; a central processing unit (CPU); and input means for inputting an operation procedure of the laser device to the CPU. The CPU includes the shutter controller, the warning controller, and the laser controller. 2. The laser beam leak detection system according to claim 1, wherein at least one of the two is driven. 5. A shutter for blocking a laser beam, a shutter sensor for detecting an open / closed state of the shutter, and a scattering sensor for detecting a part of the laser beam, wherein the scattering sensor comprises: a hollow member; A laser beam detector comprising: an optical fiber connected to a hollow member; and a photoelectric conversion element connected to the optical fiber. 6. A laser beam leak detection method for detecting a laser beam leak from a laser device incorporating a laser light source, wherein a shutter is provided to prevent a laser beam emitted from the laser light source from being emitted outside the laser device. And detecting the open / closed state of the shutter, and determining whether a shutter drive signal for closing the shutter is transmitted, and determining whether the shutter is closed. And determining whether the laser beam is scattered from an optical system for outputting the laser beam to the outside of the laser device, wherein the shutter drive signal indicates a closed state. ,and,
A laser beam leak detection method, wherein a warning signal is generated when the shutter is in a closed state and the laser beam is scattered. 7. The laser beam leakage detection method according to claim 6, wherein the laser oscillation of the laser light source is stopped when the laser beam is scattered even after a predetermined time has elapsed.