JP2023020317A - Laser module, laser oscillator, and laser processing system - Google Patents

Abstract

To provide a laser module capable of detecting deterioration of light emission characteristics and failure of laser module.SOLUTION: The laser module includes: a laser diode bar that has multiple emitters that emit laser light from the front side and leak light from the back side; and a collection lens into which leaked light is incident from the backside of all multiple emitters; and a detector that detects light passing through a focusing lens.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to laser modules, laser oscillators, and laser processing systems.

Patent Document 1 discloses a semiconductor laser device having a semiconductor laser bar having a plurality of light emitting points and a heat sink attached to one side of the semiconductor laser bar. A first submount and a molybdenum stiffener are attached to the heat sink, and a second submount is attached to the other side of the semiconductor laser bar. The first submount, the molybdenum reinforcing body, and the second submount are provided with different coefficients of linear expansion so as to suppress deformation of the semiconductor laser bar. This makes it possible to suppress deterioration of the plurality of light emitting points.

JP 2012-89585 A

The semiconductor laser bar of Patent Literature 1 cannot detect deterioration in light emission characteristics and failure of the semiconductor laser bar. Degradation of light emission characteristics and failure of semiconductor laser bars affect performance of systems using semiconductor laser bars.

An object of the present disclosure is to detect deterioration of emission characteristics and failure of a laser module in a laser module.

In order to achieve the above object, the laser module in the present disclosure includes a laser diode bar having a plurality of emitters that emit laser light from the front surface and light leaks from the back surface, An incident condenser lens and a detector for detecting light passing through the condenser lens.

A laser oscillator and a laser processing system of the present disclosure also include the laser module described above.

According to the laser module, the laser oscillator, and the laser processing system of the present disclosure, it is possible to detect deterioration of light emission characteristics and failure of the laser module.

1 is a cross-sectional view showing a laser module according to a first embodiment of the present disclosure; FIG. Cross-sectional view along the II-II line in Fig. 1 FIG. 5 is a plan view of a light guide member included in a laser module according to a second embodiment of the present disclosure; FIG. 5 is a partially enlarged cross-sectional view showing a laser module according to a third embodiment of the present disclosure; Sectional view of a housing in a laser module according to a fourth embodiment of the present disclosure FIG. 11 is a diagram showing the positions of detectors in the laser module according to the fourth embodiment of the present disclosure; Schematic diagram showing the configuration of a laser oscillator used in the laser processing system of the present disclosure

<Laser module>
<First embodiment>
A laser module according to a first embodiment of the present disclosure will be described below with reference to the drawings. 1 and 2 are sectional views showing the configuration of the laser module 1. FIG. A laser module 1 comprises a laser diode bar 10 , a housing 20 , a condenser lens 30 and a detector 40 .

The laser diode bar 10 has a rectangular shape in plan view. The laser diode bar 10 has a plurality of optical waveguide emitters 11 . A plurality of emitters 11 are arranged side by side in the longitudinal direction of the laser diode bar 10 .

The plurality of emitters 11 has a light-emitting layer (not shown) that emits light when voltage is applied and current is passed. The front end face 11a and the rear end face 11b of the optical waveguide emitter 11 are arranged so as to be opposite to each other in the lateral direction of the laser diode bar 10 . A front end surface 11a and a rear end surface 11b of the emitter 11 are provided so as to reflect light. The light reflectance of the front end surface 11a is lower than the light reflectance of the rear end surface 11b. The light reflectance of the rear end surface 11b is 90% or more and less than 100%, preferably 95% or more.

The light generated in the light-emitting layer is repeatedly reciprocated in the optical waveguide (not shown) by being reflected by the front facet 11a and the rear facet 11b, and is amplified. The amplified light is emitted as laser light from the front facet 11a along a direction orthogonal to the front facet 11a by laser oscillation.

On the other hand, when the light generated in the light emitting layer repeatedly reciprocates within the optical waveguide, part of the light generated in the light emitting layer leaks from the rear facet 11b along the direction orthogonal to the rear facet 11b. In FIGS. 1 to 6, solid-line thick arrows indicate light leaked from the rear end surface 11b.

The housing 20 has a space S penetrating from the surface 20a of the housing 20 to the opposite surface 20b on the opposite side of the surface 20a. The laser diode bar 10 is fixed in the space S so that the front end faces 11a of the plurality of emitters 11 are exposed on the surface 20a side of the housing 20 and the rear end faces 11b face the inside of the space S. As a result, light leaks toward the space S from the rear end surfaces 11 b of the emitters 11 .

The space S has a shape through which the light leaked from the rear end surfaces 11b of all the emitters 11 is led out. In other words, the space S constitutes a passage through which the light leaked from the rear end surfaces 11b of all of the plurality of emitters 11 passes and is led out of the housing 20. As shown in FIG. Light leaking from a part or all of the rear end surfaces 11b of the plurality of emitters 11 may be reflected by the inner surface of the housing 20 forming the space S when passing through the space S.

The space S specifically extends in the lateral direction of the laser diode bar 10 . Also, the thickness of the space S is thicker than the thickness of the laser diode bar 10 (FIG. 2). The laser diode bar 10 is connected via an AuSn solder layer or the like to a submount member (not shown) having relatively high heat dissipation. Furthermore, the space S has an inclined surface 20c that narrows the length of the space S in the width direction (longitudinal direction of the laser diode bar 10) from the surface 20a side toward the opposite surface 20b side. Therefore, the opening on the opposite surface 20b side of the space S becomes smaller, and the condenser lens 30, which will be described later, can be made compact. Note that the space S may have a shape in which the length in the width direction is constant without having the inclined surface 20c.

Light derived from the rear end surfaces 11 b of all of the plurality of emitters 11 enters the condenser lens 30 . The condenser lens 30 is arranged outside the housing 20 . All of the light derived from the space S is incident on the condenser lens 30 . Note that the condenser lens 30 may be configured by combining a plurality of lenses.

The detector 40 is arranged at a position (near the focal point) where the light passing through the condenser lens 30 converges. Therefore, the light leaked from the rear end surfaces 11 b of all the emitters 11 enters the detector 40 . The detector 40 outputs a detection signal corresponding to the intensity of the detected light. The detector 40 is, for example, a photodiode (eg, PIN photodiode).

Since the detector 40 and the collecting lens 30 are located outside the housing 20, the detector 40 and the collecting lens 30 are arranged in the interior of the housing 20. 30 layout flexibility can be improved. Also, the size of the housing 20 can be reduced.

Next, the operation of the laser module 1 will be described. When a voltage is applied to the plurality of emitters 11, laser light is emitted from the front facet 11a and light leaks toward the space S from the rear facet 11b.

Light leaked from the rear end surfaces 11 b of all the emitters 11 passes through the space S and is led out of the housing 20 . Light emitted from housing 20 passes through condenser lens 30 and enters detector 40 . In other words, the light leaked from the rear end surfaces 11 b of all the emitters 11 enters the detector 40 . The detector 40 outputs a detection signal corresponding to the intensity of incident light.

Next, a case where the light emission characteristic of at least one emitter 11 among the plurality of emitters 11 is degraded will be described. When the emission characteristics of at least one emitter 11 among the plurality of emitters 11 deteriorate, the intensity of light leaking from the rear end face 11b of one emitter 11 decreases. This reduces the intensity of light incident on detector 40 via space S and condenser lens 30 . Therefore, the detection signal of the detector 40 changes.

In other words, by monitoring the detection signal, it is possible to detect deterioration of the emission characteristic of at least one of the plurality of emitters 11 based on the change in the detection signal. The same applies when the intensity of the light leaking from the rear facet 11b is reduced due to a failure of the laser module 1 or the like. Therefore, deterioration of light emission characteristics and failure of the laser module 1 can be detected.

<Second embodiment>
Next, with regard to the laser module 1 according to the second embodiment of the present disclosure, mainly different parts from the first embodiment will be described with reference to FIG. The laser module 1 of the second embodiment further includes a light guide member 150. As shown in FIG.

The light guide member 150 guides the light leaked from the rear end surfaces 11 b of all the emitters 11 to the condenser lens 30 . The light guide member 150 is made in a plate shape using a transparent resin material. The light guide member 150 has an introduction surface 151 and a lead-out surface 152 opposite to the introduction surface 151 . The light guide member 150 has a shape in which the length in the width direction becomes shorter from the introduction surface 151 toward the extraction surface 152 . It should be noted that the shape of the light guide member 150 is such that all the light incident from the introduction surface 151 can be emitted from the extraction surface 152 and can be arranged in the space S (see FIG. 1). They may have the same shape or may have different shapes.

The light guide member 150 is arranged in the space S. As shown in FIG. The introduction surface 151 faces the rear end surfaces 11 b of all the emitters 11 and introduces light leaking from the rear end surfaces 11 b of all the emitters 11 . The lead-out surface 152 guides out all of the light introduced from the lead-in surface 151 . The lead-out surface 152 faces the condensing lens 30 . Therefore, the light led out from the lead-out surface 152 is led out of the housing 20 and enters the condensing lens 30 .

The light guide member 150 allows the light leaked from the rear end faces 11b of all the emitters 11 to enter the condenser lens 30 without fail.

Note that the light guide member 150 may contain a scatterer inside. The light guided inside the light guide member 150 is scattered by the scatterer. Therefore, the light leaked from the rear end face 11b of the plurality of emitters 11 is homogenized in intensity when guided through the interior of the light guide member 150, and the light with the homogenized intensity is led out from the lead-out surface 152. be able to.

<Third Embodiment>
Next, with regard to the laser module 1 according to the third embodiment of the present disclosure, mainly different parts from the first embodiment will be described with reference to FIG. 4 . The laser module 1 of the third embodiment further includes a dimming member 260 .

The dimming member 260 attenuates light leaking from the rear end faces 11b of the plurality of emitters 11. As shown in FIG. The dimming member 260 is a dimming filter, a scattering plate, a partial transmission mirror, and the like. Attenuating member 260 is positioned between condenser lens 30 and detector 40 . The dimming member 260 has a size that allows the light that has passed through the condenser lens 30, that is, the light leaked from the rear end surfaces 11b of all the emitters 11 to enter. That is, the dimming member 260 dims the light leaked from the rear end faces 11b of all of the multiple emitters 11 . Detector 40 detects light that has passed through dimming member 260 .

As a result, even when the intensity of the light leaked from the rear end faces 11b of the plurality of emitters 11 is relatively high, the detector 40 detects the light leaked from all the rear end faces 11b of the plurality of emitters 11. It can be appropriately detected within the detectable light amount range. Needless to say, the position and size of the dimming member 260 are not limited to those described above as long as the light leaked from all the rear end faces 11b of the plurality of emitters 11 can be dimmed. The dimming member 260 may be arranged between the rear end surface 11b and the detector 40, and may be arranged between the housing 20 and the condenser lens 30, for example.

<Fourth Embodiment>
Next, the laser module 1 according to the fourth embodiment of the present disclosure will be described mainly with reference to FIGS.

In the fourth embodiment, the inner surface of the housing 20 that forms the space S is composed of a reflecting surface 321 . The reflecting surface 321 reflects the light leaking from the rear end surface 11b so as to scatter the light.

Reflective surface 321 has a rough surface. The reflecting surface 321 is a satin surface having fine irregularities. Thereby, the reflecting surface 321 can efficiently scatter the light leaked from the rear end surface 11b. Note that the reflective surface 321 may be coated with a coating agent containing scatterers such as barium nitrate and titanium oxide.

Also, the absorption rate of the light leaked from the rear end surface 11b in the reflecting surface 321 is 10% or less. As a result, even if the light leaked from the rear end surface 11b is repeatedly reflected, the attenuation of the intensity of the light reflected from the rear end surface 11b can be suppressed.

The space S is provided so that the light leaked from the rear end surfaces 11 b of all the emitters 11 and reflected by the reflecting surface 321 is led out of the housing 20 . In other words, the space S constitutes a passage through which the light leaked from the rear end surfaces 11 b of all of the plurality of emitters 11 is guided to the outside of the housing 20 . Further, the space S has a shape in which the reflecting surface 321 repeatedly reflects the light leaked from the rear end surface 11b. The space S has, for example, a crank-shaped cross section. The shape of the space S may be any structure as long as it can promote the scattering of light and uniformize the intensity of the light.

The light leaked from the rear end faces 11b of all the emitters 11 is repeatedly reflected by the reflecting surface 321, so that the intensity of the light leaked from the rear end faces 11b of all the emitters 11 is made uniform within the space S. be. The light whose intensity has been uniformized in the space S is led out of the housing 20 and enters the condensing lens 30 .

Also, as shown in FIG. 6, detector 40 detects a portion of the light that has passed through condenser lens 30 . Detector 40 is positioned closer to condenser lens 30 than the focal point of condenser lens 30 . The detector 40 outputs a detection signal corresponding to the intensity of the detected light.

As described above, the reflection surface 321 equalizes the intensity of the light leaked from the rear end surfaces 11b of all the emitters 11 . When the light emission characteristics of at least one emitter 11 out of the plurality of emitters 11 deteriorate, the intensity of light leaking from the rear end face 11b of one emitter 11, and thus the intensity of light uniformized by the reflecting surface 321, decreases. descend. Thus, the intensity of a portion of the light incident on detector 40 via condenser lens 30 is reduced. Thereby, the detection signal of the detector 40 changes.

In this way, even when the detector 40 detects part of the light that has passed through the condenser lens 30, by monitoring the detection signal, at least one of the plurality of emitters 11 is detected based on changes in the detection signal. Degradation of the emission characteristics of the two emitters 11 can be detected. Further, since the detector 40 detects part of the light that has passed through the condenser lens 30, even if the intensity of the light leaked from the rear end face 11b of the plurality of emitters 11 is relatively high, the detector 40 It can be appropriately detected within the detectable light amount range. Since the intensity of the light is uniform within the space S, the overall light quantity can be estimated even in the form of detecting a part of the light.

<Laser oscillator and laser processing system>
The laser processing system is a system used for metal processing using high-power laser light, and includes a high-power laser oscillator 2 that outputs a laser light of 100 W to several kW or more, an optical fiber (not shown), a laser processing head (not shown), It also consists of a movable stage (not shown) for setting a workpiece. A high-power laser oscillator 2 used in a laser processing system includes a plurality of laser modules 1, a diffraction grating 2a, and an external resonance mirror 2b, as shown in FIG.

A plurality of laser modules 1 are arranged in a line. The diffraction grating 2a is a transmissive or reflective diffraction grating. The external resonant mirror 2b is a partially transmissive mirror.

Laser light is emitted from the plurality of emitters 11 of each of the plurality of laser modules 1 . Laser light emitted from each of the plurality of laser modules 1 enters the diffraction grating 2a.

The diffraction grating 2a diffracts and emits the incident laser light at a diffraction angle determined by the wavelength of the laser light. A laser beam emitted from the diffraction grating 2a is incident on the external resonance mirror 2b.

The external resonance mirror 2b vertically reflects part of the incident laser light in the direction of the diffraction grating 2a. As a result, only the wavelengths that satisfy the diffraction conditions of the diffraction grating 2a due to the positional relationship among the individual emitters 11 of the plurality of laser modules 1, the diffraction grating 2a, and the external resonance mirror 2b can be detected by the laser module 1 and the external resonance mirror 2b. Laser light is output by feedback between and external resonance oscillation. In this case, the reflectance of the front facet of the laser module 1 is set to 0.5% or less, more preferably 0.1% or less, so that only external resonance oscillation occurs at the external resonance mirror 2b, and the optical waveguide of the laser module 1 is It is desirable not to generate internal resonance oscillation at the end surfaces 11a and 11b. A beam twister unit (not shown) may be arranged between the plurality of laser modules 1 and the diffraction grating 2a to rotate the laser light by 90 degrees around the optical axis.

When metal processing or the like is being performed using a laser processing system, the detection signals output from the detectors 40 of the plurality of laser modules 1 constituting the high-power laser oscillator 2 are monitored in real time. . Therefore, changes in the detection signal are detected in real time. Therefore, it is possible to individually detect the deterioration of the light emission characteristics and the failure of the laser module 1 . In addition, it is possible to detect in which laser module 1 among the plurality of laser modules 1 the deterioration of the light emission characteristic or the like has occurred.

The present disclosure is not limited to the embodiments described above. As long as they do not deviate from the gist of the present disclosure, various modifications to the present embodiment and forms constructed by combining components of different embodiments are also included within the scope of the present disclosure.

For example, in each embodiment the collection lens 30 and the detector 40 are located outside the housing 20 . Alternatively, the condenser lens 30 may be arranged within the space S of the housing 20 . Also, the condenser lens 30 and the detector 40 may be arranged within the space S of the housing 20 .

Also, in each embodiment, the laser module 1 may not have the housing 20 . In this case, the condenser lens 30 is arranged so that light leaking from the rear end faces 11b of all of the plurality of emitters is incident thereon.

Also, in the second embodiment, the light guide member 150 is a single plate-like member, but instead of this, it may be composed of a plurality of plate-like members, a plurality of rod-like members, and the like. Also, the light guide member 150 may be partially or wholly arranged outside the housing 20 .

Further, in the second embodiment, the outer surface of the light guide member 150 may be provided with grooves for diffusing the light leaked from the rear end face 11b. According to this, the light leaked from the rear end surface 11b is diffused within the light guide member 150, so that the intensity of the light leaked from the rear end surfaces 11b of all of the plurality of emitters 11 can be made uniform. In this case, the detector 40 may detect part of the light that has passed through the condenser lens 30 as in the fourth embodiment.

In each of the above-described embodiments, laser light is emitted from the front facet 11a of the emitter 11 and light leaks from the rear facet 11b of the emitter 11, but the present invention is not limited to this. In other words, the laser light should be emitted from the surface (that is, the surface) of the emitter 11 that is exposed to the outside from the housing 20 . In addition, it is only necessary for light to leak from the surface of the emitter 11 facing the space S (that is, the back surface).

INDUSTRIAL APPLICABILITY The present invention is widely applicable to laser modules, high-power laser oscillators, and laser processing systems.

REFERENCE SIGNS LIST 1 laser module 2 high output laser oscillator 10 laser diode bar 11 emitter 11a front end face 11b rear end face 20 housing 30 condenser lens 40 detector 150 light guide member 260 dimming member 321 reflecting surface S space

Claims (7)

a laser diode bar having a plurality of emitters that emit laser light from the front surface and leak light from the back surface;
a condensing lens into which light leaking from the rear surfaces of all of the plurality of emitters is incident;
a detector that detects light that has passed through the condenser lens;
laser module. further comprising a light guide member that guides light leaked from the back surface to the condensing lens,
The laser module according to claim 1. It further comprises a dimming member that attenuates light leaked from the back surface,
The laser module according to claim 1 or 2. further comprising a housing having a passage through which light leaking from the back surface passes and is led to the outside;
the condenser lens is arranged outside the housing, and the light passing through the passage is incident thereon;
The laser module according to any one of claims 1 to 3. the housing further includes a reflective surface surrounding the passageway and reflecting to scatter light leaking from the back surface;
The passage guides the light reflected by the reflecting surface to the outside,
the detector detects a portion of the light that has passed through the collection lens;
The laser module according to claim 4. A plurality of laser modules according to any one of claims 1 to 5,
laser oscillator. A plurality of laser modules according to any one of claims 1 to 5,
Laser processing system.

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