JP5042013B2 - Laser heating device - Google Patents

Description

The present invention is, for example, by a laser beam emitted from the semiconductor laser, soldering or, resin bonding, relates to laser heating equipment for heating-processing such as welding.

  Conventionally, as a laser heating apparatus that performs non-contact heating and processing using laser light, for example, a laser diode module (semiconductor laser array) in which a plurality of laser diodes are stacked, and a laser emitted from the plurality of laser diodes A lens composed of a collimating lens that collimates light (collimated light) and a condensing lens that condenses collimated laser light has been proposed (for example, see Patent Document 1). . With this configuration, the conventional laser heating apparatus can perform heating / processing on the object to be heated placed at the focal position of the condenser lens.

However, heating and processing with laser light increase the temperature of the object to be heated as long as laser irradiation is continued. However, in the configuration of the conventional laser heating apparatus described above, the object to be heated is performed when performing soldering or resin bonding. The temperature of the object could not be measured, and no abnormal heat generation, which was a sign of burnt spots on the periphery of the solder or the resin, could not be detected.
JP 2002-9388 A

In view of the above problems, the present invention detects abnormal heat generation that is a sign of the occurrence of temperature changes or burns when the solder or resin at the processing point is melted, and the soldering or resin that has no burns in the periphery is damaged. and to provide a laser heating equipment etc. without resin bonding becomes possible.

  In order to achieve the above object, the present invention provides an infrared sensor that generates a signal based on an integrated value of infrared spectral radiance emitted from an object to be heated such as solder or resin. And before performing laser heating and processing, the relational expression of the calibration value between the output signal of the infrared sensor and the measured temperature of the object to be heated of the master is obtained in advance. In actual laser heating / processing, the temperature of the object to be heated is calculated based on the output signal of the infrared sensor and the relational expression.

That is, the laser heating apparatus according to claim 1 is a laser emitting unit that emits a laser beam to be irradiated on an object to be heated, and an infrared ray that generates a signal based on an integrated value of spectral radiance of infrared rays received by the light receiving surface. A sensor, an imaging device that captures visible light, and the laser beam; the received laser beam is emitted toward the object to be heated; and is emitted from the object to be heated and its surroundings. Or a mirror that receives reflected light, and infrared rays that are radiated or reflected from the object to be heated and its surroundings and received by the mirror, excluding light having a wavelength of the laser beam, are the infrared rays. An optical system that guides to the light receiving surface of the sensor and guides visible light to the imaging device, a calibration value of the level of the signal generated by the infrared sensor and the actual temperature of the object to be heated Comprising a storage unit for storing engagement expression advance, and a temperature measuring unit for calculating a temperature of the object to be heated with the generated signal based on said relationship by the infrared sensor, the laser emitting unit, the Two or more laser diodes emitting laser light, a lens for suppressing the spread of each laser light emitted from each laser diode in the FAST direction, and the lens are joined, and laser emission from each laser diode An adjustment mechanism capable of adjusting the position of the lens with respect to the end surface so that a part of the laser power density distribution in the SLOW direction of each laser beam interferes with the processing surface, and the laser beam from the lens The laser irradiation range on the processing surface is rectangular or elliptical .

According to the present invention, a temperature change at a processing point, a rapid temperature change before and after a melting change such as solder or resin, a rapid temperature change before and after the occurrence of kogation in the periphery of the solder or resin, It is possible to detect that a desired process such as soldering or resin bonding has been performed, detect the occurrence of kogation, prevent the occurrence of kogation, and the like. Furthermore, the processing state can be observed with an imaging device .

  Further, by making the laser irradiation range rectangular or elliptical, it is possible to sufficiently cope with soldering or the like on the processed surface where the land and the resin substrate are lined up, such as FPIC and FPC.

Hereinafter, with the laser heating equipment in the embodiment of the present invention will be described sprinkled with drawings.
In the following embodiments, an infrared sensor that generates a signal based on the integrated value of the spectral radiance of infrared rays received by the light receiving surface is provided. And before performing laser heating and processing, the relational expression of the calibration value between the output signal of the infrared sensor and the measured temperature of the object to be heated of the master is obtained in advance. Then, during actual laser heating / processing, infrared light except for light having the wavelength of the laser light out of light to be radiated or reflected from the object to be heated and its peripheral portion is transmitted to the light receiving surface of the infrared sensor. The temperature of the object to be heated is calculated based on the signal generated by the infrared sensor and the relational expression obtained in advance.

(Embodiment 1)
FIG. 1 shows the configuration of the laser heating apparatus according to the first embodiment. The laser heating device irradiates the object to be heated with laser light to heat the object to be heated.

  In FIG. 1, a laser emitting unit 1 emits laser light having a constant wavelength. The laser emitting unit includes, for example, a semiconductor laser or a semiconductor excitation laser. Here, an example in which a laser diode that oscillates laser light having a wavelength of 920 nm is provided will be described. Of course, the wavelength of the laser beam is not limited to 920 nm. In general, the wavelength of laser light from a laser diode is 1.6 μm or less.

  The condensing lens 2 condenses the laser light from the laser emitting unit 1 and heats the solder 3 that is an object to be heated placed at the condensing position. The solder 3 is applied on the land 5 of the printed circuit board 4. Here, a case where the object to be heated is solder will be described as an example.

  When the solder 3 is heated by laser irradiation, infrared rays are emitted from the solder 3, the land 5 around the solder 3, and the printed board 4. Further, the irradiated laser light or visible light is reflected from the solder 3 and its peripheral part. The laser light cut filter 6 receives light emitted or reflected from the solder 3 or the like and cuts light having a wavelength of laser light (920 nm). The visible light cut filter 7 receives light transmitted through the laser light cut filter 6 and cuts visible light. Therefore, infrared rays other than light (infrared rays) having a wavelength of laser light out of infrared rays emitted from the solder 3 or the like are incident on the condenser lens 8.

  The condensing lens 8 condenses the transmitted light of the visible light cut filter 7 and makes the infrared light except the light having the wavelength of the laser light enter the light receiving surface 10 of the infrared sensor 9 placed at the condensing position. As described above, in the laser heating apparatus according to the first embodiment, the light emitted or reflected from the solder 3 or its peripheral part is received, and the infrared light except the light having the wavelength of the laser light (920 nm) is received as the light receiving surface of the infrared sensor. The optical system that leads to the light is composed of a laser light cut filter 6, a visible light cut filter 7, and a condenser lens 8. The arrangement order of the condenser lens 8, the laser light cut filter 6, and the visible light cut filter 7 may be arbitrary. Further, for example, a filter that transmits light having a wavelength longer than the wavelength of the laser light may be used instead of the laser light cut filter.

  The infrared sensor 9 generates a signal based on the integrated value of the infrared spectral radiance received by the light receiving surface 10. Here, as an infrared sensor, an InGaAs PIN photodiode having a predetermined sensitivity range in which the sensitivity reaches a peak at a wavelength of 2.3 μm will be described as an example.

  Although not shown, the laser heating apparatus includes a storage unit that stores in advance a relational expression of a calibration value (calibration value) between the level of the signal generated by the infrared sensor 9 and the actually measured temperature of the solder 3, and the infrared sensor 9. And a microcomputer which is a temperature measuring unit for calculating the temperature of the solder 3 based on the signal generated by the above and the relational expression.

  Next, the principle of temperature measurement in the first embodiment will be described using the graphs shown in FIGS. FIG. 2 shows a spectral sensitivity characteristic of an InGaAs / PIN photodiode having a predetermined sensitivity range in which the sensitivity reaches a peak at a wavelength of 2.3 μm. As shown in FIG. 2, the InGaAs / PIN photodiode has a relative sensitivity of 10% or more with respect to a wavelength of 1.2 μm to 2.6 μm.

  FIG. 3 shows the transmittance (infrared absorption characteristics) of BK7 (crown borosilicate crown optical glass) which is an optical component material used for a condensing lens, a half mirror described later, synthetic quartz, and anhydrous synthetic quartz. In FIG. 3, the solid line shows a graph of the transmittance of BK7, the one-dot chain line shows the graph of the transmittance of synthetic quartz, and the broken line shows the graph of the transmittance of anhydrous synthetic quartz. Hereinafter, the case where BK7 is used as an optical component material will be described as an example.

FIG. 4 is a so-called Planck radiation law, and shows the spectral radiance characteristics of infrared rays emitted from a black body. Here, as an example, 0 ° C (273K), 127 ° C (400K) near the lower limit of measurement temperature, 227 ° C (500K) near the melting point of lead-free solder, peripheral part of lead-free solder Shows a graph of spectral radiance at 327 ° C. (600 K), which is a temperature near the temperature at which kogation occurs. In addition, although the graph displays the upper part from the radiance of 10 ⁻⁸ W / (cm 2 · sr · μm), 10 ⁻⁵ W / (cm 2 · sr · μm) is practically used to avoid the influence of noise. ) Treat the above as a practical area.

  5 to 7 show practical radiance detected by the infrared sensor (InGaAs / PIN photodiode) 9 when the temperature of the processing point (object to be heated) is 227 ° C, 127 ° C, and 327 ° C. 5 to 7, a broken line indicates a graph of infrared spectral radiance emitted from a processing point, and a dashed-dotted line indicates a graph of infrared spectral radiance after passing through BK7 which is an optical component material such as a condenser lens. The solid line shows a graph of practical radiance of infrared rays detected by the infrared sensor 9.

As described above, the infrared sensor 9 actually detects the solid line shown in FIGS. 5 to 7 obtained by multiplying the spectral sensitivity characteristic shown in FIG. 2, the infrared absorption characteristic shown in FIG. 3, and the spectral radiance characteristic shown in FIG. The infrared sensor 9, the solid line and ^{10 -5 W / (cm2 · sr} · μm) 10 -5 W / (cm2 · sr · μm range area surrounded by the line (of the infrared rays received by the light receiving surface 10) A signal having a signal level based on the above spectral radiance integrated value) is generated.

  As shown in FIGS. 5 to 7, the output signal level of the infrared sensor 9 is slight at 127 ° C., but increases to 5 times or more at 227 ° C., and further monotonously increases to 10 times or more at 327 ° C. ing.

  Therefore, before carrying out the actual laser heating / processing, laser irradiation is performed on the master solder in which the thermocouple for calibration is embedded, and the output signal level of the infrared sensor 9 and the output signal level of the thermocouple (measured temperature) ) In advance, the temperature of the solder 3 can be measured almost accurately during actual laser heating and processing.

  For example, instead of the laser beam cut filter, an optical bandpass filter (hereinafter referred to as BPF) that can transmit only light in a specific wavelength range longer than the wavelength of the laser beam may be used. A BPF is disposed on the light receiving surface 10 of the infrared sensor 9. When the BPF is used, an infrared sensor having practical sensitivity to light in a specific wavelength range transmitted through the BPF is used as the infrared sensor that receives the transmitted light through the BPF. With this configuration, it becomes possible to detect that the processing point (object to be heated) has reached a specific temperature. That is, according to this configuration, the output signal level of the infrared sensor 9 rapidly increases when the processing point reaches the specific temperature, so that the BPF is effective when detecting the specific temperature.

  For example, a BPF that transmits only a narrow-band infrared light having a wavelength of 1064 nm and a half width of 10 μm is useful for detecting that the processing point is about 200 degrees (temperature near the melting point of solder). Yes, by keeping this temperature, it is possible to realize soldering that melts reliably and the peripheral portion is not damaged.

  Further, as can be seen from the spectral radiance characteristics shown in FIG. 4, in order to measure the temperature of the object to be heated at 400K or higher, the infrared sensor has a predetermined sensitivity range in which the sensitivity peaks at a wavelength of 1.2 μm or higher It is desirable to have

  As described above, according to the first embodiment, the output signal level of the infrared sensor that rapidly increases when the processing point (object to be heated) reaches a temperature of 100 ° C. or higher is captured and rises during laser irradiation. The temperature of the object to be heated can be measured almost accurately at 400K or higher.

  Therefore, it detects the temperature change at the processing point (object to be heated), the rapid temperature change before and after the melting change of the solder and resin, and the rapid temperature change before and after the occurrence of kogation around the solder and resin. Thus, it is possible to detect completion of desired processing such as soldering and resin bonding, detection of kogation, and prevention of kogation.

(Embodiment 2)
FIG. 8 shows the configuration of the laser heating apparatus according to the second embodiment. However, the same members as those described with reference to FIG.

  In FIG. 8, an optical fiber 11 emits laser light from the laser emitting unit 1 into the air. The collimating lens 12 collimates the laser light from the optical fiber 11 (hereinafter referred to as collimated light). The half mirror 13 is provided with a thin film filter that reflects collimated light and transmits light radiated or reflected from the solder 3 or its peripheral land 5 or printed circuit board 4. For example, a half mirror provided with a thin film coating that reflects only 920 nm (light having a wavelength of laser light) may be used. Further, instead of the half mirror, a folded BPF that can transmit only infrared rays having a wavelength longer than that of the laser beam may be disposed.

  In the second embodiment, an optical system that receives light emitted or reflected from the solder 3 or its peripheral portion and guides infrared light other than light having a wavelength of laser light (920 nm) to the light receiving surface 10 of the infrared sensor 9, The half mirror 13, the laser light cut filter 6, the visible light cut filter 7, and the condenser lens 8 are configured. The arrangement order of the condenser lens 8, the laser light cut filter 6, and the visible light cut filter 7 may be arbitrary.

  The preamplifier 14 amplifies the output signal from the infrared sensor 9. Although not shown, the laser heating apparatus includes a storage unit that stores in advance a relational expression of calibration values between the output signal level of the preamplifier 14 and the actually measured temperature of the solder 3. Although not shown, the meter 15 includes a microcomputer that calculates the temperature of the solder 3 based on the output signal of the preamplifier 14 and the relational expression as a temperature measurement unit. The meter 15 displays the measured temperature calculated by the microcomputer.

  Further, the laser heating device is configured to output a detection signal from the meter 15 to the laser emitting unit 1. According to this configuration, for example, when a rapid temperature change before and after the melting change of the solder 3 is detected, the laser power is reduced, or a rapid temperature change before and after the occurrence of kogation in the periphery of the solder 3 is detected. When this is done, laser oscillation can be stopped, and automatic soldering can be completed and kogation can be prevented.

  According to the above configuration, by observing the temperature change displayed on the meter 15, it is possible to detect solder melting, detect approximate temperature, and detect kogation. Further, as described above, automatic soldering can be completed and kogation can be prevented. As in the first embodiment, a BPF that can transmit only infrared rays having a longer wavelength than the laser beam may be disposed on the light receiving surface 10 of the infrared sensor 9. Although the case where the laser beam is made parallel is described, even if the F value of the collimating lens is adjusted to make it non-collimated, the same is achieved by shortening the distance between the exit port of the optical fiber and the half mirror. Effects can be obtained.

(Embodiment 3)
FIG. 9 shows the configuration of the laser heating apparatus according to the third embodiment. However, the same members as those described with reference to FIGS. 1 and 8 are denoted by the same reference numerals, and description thereof is omitted.

  In FIG. 9, the hot mirror 16 receives the transmitted light of the half mirror 13 through the condenser lens 8, reflects the infrared light, guides it to the light receiving surface 10 of the infrared sensor 9, transmits visible light, and transmits the second light. The light is guided to the laser light cut filter 17. A camera (imaging device) 18 that receives visible light through the laser light cut filter 17 images the solder 3 and its peripheral part.

  In the third embodiment, light emitted or reflected from the solder 3 or its peripheral part is received, and infrared light other than the laser light having a wavelength (920 nm) is guided to the light receiving surface 10 of the infrared sensor 9 and visible light is also emitted. An optical system that guides the light to the camera 18 includes a half mirror 13, a condenser lens 8, two laser light cut filters 6 and 17, and a hot mirror 16. Instead of the laser light cut filter 6, a filter or BPF that transmits light having a wavelength longer than the wavelength of the laser light may be used. For example, the BPF is disposed on the light receiving surface 10 of the infrared sensor 9.

  In the laser heating device, an aperture 19 for specifying a position where temperature measurement is performed is attached in the vicinity of the optical path axis 20 to the light receiving surface 10 of the infrared sensor 9. Accordingly, by changing the size, shape, and arrangement position of the aperture 19 and changing the processing point detection visual field 21, temperature abnormalities around the solder 3 are detected, or the temperature of a specific portion of the laser irradiation range is measured. It becomes possible to do.

  As described above, according to the third embodiment, by providing the infrared sensor 9 and the camera 18, it is possible to observe a change in the appearance of the processing point simultaneously with a temperature change of the processing point during laser irradiation. In addition, since the field of view of the machining point can be changed by changing the arrangement position or size of the aperture 19, it is possible to detect the occurrence of kogation in the peripheral part, the detection of temperature fluctuations at a minute specific position, and the prevention of kogation. it can.

  Note that a cold mirror may be used in place of the hot mirror by reversing the arrangement positions of the infrared sensor 9 and the camera 18. Further, the arrangement position of the infrared sensor 9 and the camera 18 may be reversed, and a folded BPF that can transmit only infrared rays having a wavelength longer than the laser beam may be arranged instead of the hot mirror. When a BPF is disposed instead of the hot mirror, visible light after being reflected by the BPF and transmitted through the laser light cut filter 17 is incident on the camera 18. Therefore, the camera 18 can image the processing point. According to the third embodiment, it is possible to realize soldering that surely melts and has no peripheral portion while monitoring with a camera.

  In addition, although soldering has been described as an example, the present invention can be similarly performed even when resin bonding, resin marking, or two or more resin bondings are performed. Further, although an InGaAs PIN photodiode is used as the infrared sensor, any infrared sensor having a peak sensitivity at a wavelength of 1.2 μm or more may be used. For example, a compound semiconductor may be used.

  In addition, here, for the sake of simplicity of explanation, BK7 that absorbs infrared rays having a wavelength of 1.7 μm or more without an AR coating is used as an optical component such as each condenser lens and mirror. However, crown glass or achromatic It may be a lens. In particular, anhydrous synthetic quartz is suitable because it does not decrease the transmittance even in the vicinity of 2.7 μm, which is the limit of sensitivity of the InGaAs PIN photodiode, and can improve the S / N ratio. Moreover, you may give AR coating with respect to the wavelength of the sensitivity range of an infrared sensor.

(Embodiment 4)
In the laser heating apparatus in each of the first to third embodiments, the shape of the laser light (laser irradiation range) formed at the processing point is limited to a spot shape (perfect circle shape). Therefore, in the laser heating apparatus in each of the first to third embodiments described above, it is sufficient to cope with a processed surface in which lands and resin substrates are aligned, such as FPIC (field programmable interconnect component) and FPC (flexible printed wiring board). is not.

  In the fourth embodiment, the shape of the laser beam formed on the processed surface is rectangular or elliptical (hereinafter referred to as a rectangular shape or the like), so that the land and the resin substrate can be formed like FPIC or FPC. To be able to cope with soldering etc. to the processed surfaces that are lined up.

  Moreover, in this Embodiment 4, the wide range including the laser irradiation range of the rectangular shape etc. and its periphery is set as the detection range (temperature observation range) of the infrared sensor. Infrared radiant energy increases in proportion to the fourth power of temperature according to Stefan-Boltzmann's law. By widening the temperature observation area of the infrared sensor, the temperature rise when abnormal heat generation occurs in that temperature observation area The infrared sensor can quickly detect, and control such as reducing the laser power can be performed quickly.

FIG. 10A shows the configuration of the laser heating apparatus according to the fourth embodiment. However, the same members as those described with reference to FIGS. 1, 8, and 9 are denoted by the same reference numerals, and description thereof is omitted.
The laser heating apparatus according to the fourth embodiment is an optical system for making the shape of the laser beam formed on the processed surface rectangular or the like, and instead of a condenser lens, a cylindrical lens is formed between the half mirror 13 and the processed surface. The point that the lens is arranged is different from the third embodiment described above.

  In FIG. 10A, the cylindrical lens 22 receives the laser beam reflected by the half mirror 13 which is a folding mirror, and forms a rectangular or other laser beam on the processed surface. Here, description will be made taking solder applied to each land of the FPIC 23 as an example of the object to be heated.

  FIG. 10B is a side view of the laser heating device as viewed from the y direction, and shows the collimator lens 12, the half mirror 13, the cylindrical lens 22, and the FPIC 23 extracted. FIG. 10C is a top view showing the shape of the laser beam formed on the processed surface.

  As shown in FIGS. 10B and 10C, the cylindrical lens 22 converts the received spot-like (true round) laser light into a rectangular or elliptical shape (laser irradiation range 24) on the processing surface.

  The size of the laser irradiation range 24 in the x direction can be adjusted by changing the distance to the processing surface of the cylindrical lens 22. In addition, as shown in FIG. 10C, in the fourth embodiment, a range wider than the laser irradiation range 24 is set as the temperature observation region 25.

  Note that the spread angle of the laser beam can be adjusted by adjusting the distance of the collimating lens 12 to the optical fiber 11. In addition, when a cylindrical lens is arranged instead of the collimating lens 12 as will be described later, the spread angle of the laser light can be adjusted by adjusting the distance of the cylindrical lens to the optical fiber 11.

  In FIG. 10A, the folding mirror 26 is provided with a thin film coat or a thin film filter that transmits visible light and reflects infrared rays in the vicinity of 2 μm. The folding mirror 26 receives the transmitted light of the half mirror 13 through the condenser lens 8 (a convex lens with a spherical aberration corrected such as an achromatic lens), reflects the infrared light in the vicinity of 2 μm, and receives the light receiving surface 10 of the infrared sensor 9. At the same time, the visible light is guided to a camera (for example, a CCD surface of a CCD camera) 18. The camera 18 that receives visible light through the second laser light cut filter 17 can enlarge and observe the processed surface without distortion.

The preamplifier (amplifier circuit) 14 is a high gain amplifier and amplifies the output signal level of the infrared sensor 9 several hundred times or more.
In the fourth embodiment, light radiated or reflected from the temperature observation region (object to be heated and its peripheral portion) 25 is received, and infrared light other than the light having the wavelength of the laser light is transmitted to the light receiving surface 10 of the infrared sensor 9. An optical system that guides the visible light to the camera 18 and includes the half mirror 13, the condenser lens 8, the folding mirror 26, and the two laser light cut filters 6 and 17.

Subsequently, laser power control of the laser heating apparatus according to the fourth embodiment will be described.
In FIG. 10A, the laser control device 27 that controls the laser power so that the temperature of the object to be heated becomes a preset temperature Ts, calculates the temperature of the laser emitting unit 1 and the object to be heated. A temperature level conversion circuit (temperature measuring unit) 28 for performing the operation, a volume 29 for setting the set temperature Ts, and a control unit 30 for controlling a current supplied to a laser diode (LD element) included in the laser emitting unit 1. . Although not shown, the laser control device 27 outputs the output signal level of the preamplifier 14 and the measured temperature of the solder applied to each land of the FPIC 23 (for example, an average value of the measured temperature of the solder applied to each land or a specific value) A storage unit that stores in advance a relational expression of a calibration value (calibration value) with a measured temperature of solder applied to the land.

The temperature level conversion circuit 28 calculates the temperature of the object to be heated based on the output signal of the preamplifier 14 and the relational expression, and generates a signal indicating the temperature.
A preset temperature Ts is preset in the volume 29, and the control unit 30 outputs an output signal (corresponding to the temperature of the object to be heated) of the temperature level conversion circuit 28 and a signal generated by the volume 29 (to the preset temperature Ts). The current supplied to the laser emitting unit 1 is controlled so that the temperature of the object to be heated becomes the set temperature Ts.

  As described above, according to the fourth embodiment, the cylindrical lens can make the shape of the laser light formed on the processed surface rectangular or the like, and the land and the resin substrate are lined up like FPIC or FPC. It is possible to sufficiently cope with soldering on the processed surface and resin bonding in a rectangular region or an elliptical region.

  The shape of the laser light formed on the processed surface can be arbitrarily enlarged / reduced by moving the focal position and the fixed position of the collimating lens 12 and the cylindrical lens 22 back and forth, and the aspect ratio of the shape of the laser light. Can be changed arbitrarily.

  In addition, a cylindrical lens may be disposed in place of the collimating lens 12, and a convex lens having a spherical aberration corrected such as an achromatic lens may be disposed in place of the cylindrical lens 22. That is, first, after changing the aspect ratio of the laser light with a cylindrical lens, the laser light with the changed aspect ratio is condensed with a convex lens so that the shape of the laser light formed on the processed surface is rectangular or the like. Also good. Also in this case, the shape of the laser beam formed on the processing surface can be arbitrarily enlarged / reduced by moving the focal position and fixed position of the cylindrical lens and convex lens back and forth, and the aspect ratio of the shape of the laser beam can be arbitrarily set. Can be changed.

(Embodiment 5)
FIG. 11 shows the configuration of the laser heating apparatus in the fifth embodiment. However, the same members as those described with reference to FIGS. 1, 8, 9, and 10 are denoted by the same reference numerals, and description thereof is omitted.

  The laser heating apparatus in the fifth embodiment returns infrared rays emitted or reflected from the temperature observation region 25 to the optical fiber, and removes infrared rays except for light (infrared rays) having a wavelength of the laser light emitted from the temperature observation region 25. The point of detection by the infrared sensor built in the laser emitting unit 1 is different from that of the fourth embodiment.

In FIG. 11, the optical fiber 11 has a core portion 31 and a cladding portion 32. Laser light is emitted from the core portion 31 of the optical fiber 11.
The folding mirror 33 is provided with a thin film coat or a thin film filter that reflects infrared rays and transmits visible light. The folding mirror 33 receives the light emitted or reflected from the temperature observation region 25 via the cylindrical lens 22, reflects the infrared light, guides it to the collimating lens 12, and transmits visible light to the condenser lens 8. Lead.

The collimating lens 12 guides the infrared light reflected by the folding mirror 33 to the cladding portion 32 of the optical fiber 11.
In the fifth embodiment, the laser emitting unit 1 includes an LD element 34, a condenser lens 35, a folding mirror 36, an infrared sensor 9, and a preamplifier 14.

  The folding mirror 36 is provided with a thin film filter or thin film coat that transmits infrared light but reflects light having a wavelength of laser light. The folding mirror 36 reflects the laser light emitted from the LD element 34 and guides it to the condenser lens 35. The condenser lens 35 guides the laser light from the folding mirror 36 to the core portion 31. In this way, the laser light emitted from the LD element 34 is coupled to the optical fiber 11.

  On the other hand, the folding mirror 36 separates the infrared light having the wavelength of the laser light from the infrared light returned through the clad portion 32 and guides the infrared light except the infrared light having the wavelength of the laser light to the light receiving surface 10 of the infrared sensor 9.

  In the fourth embodiment, the optical system that receives the light emitted or reflected from the temperature observation region 25 and guides the infrared light except the light having the wavelength of the laser light to the light receiving surface 10 of the infrared sensor 9 is provided with the two folding mirrors 33. , 36 and a condenser lens 35. A laser light cut filter may be installed between the folding mirror 36 and the light receiving surface 10 of the infrared sensor 9. Similarly to the fourth embodiment, a cylindrical lens may be arranged instead of the collimating lens 12 and a convex lens may be arranged instead of the cylindrical lens 22.

(Embodiment 6)
FIG. 12 shows the configuration of the laser heating apparatus according to the sixth embodiment. However, the same members as those described based on FIGS. 1 and 8 to 11 are denoted by the same reference numerals, and description thereof is omitted.

  The laser heating apparatus in the sixth embodiment is different from the above-described fifth embodiment in that the shape of the laser beam formed on the processed surface is made rectangular by a scan mirror. That is, the processing surface is irradiated with laser light by line scanning or two-dimensional scanning, and the laser irradiation range on the processing surface is made rectangular or elliptical.

  In FIG. 12, the scan mirror 37 is provided with a thin film coat or thin film filter that reflects infrared light and transmits visible light. Further, the scan mirror 37 can swing around the rotation shaft 38. The scan mirror 37 reflects the laser light from the collimating lens 12 while reciprocally swinging by a predetermined angle about the rotation shaft 38. The condensing lens (convex lens corrected for spherical aberration such as an achromatic lens) 2 condenses the laser beam reflected by the reciprocally oscillating scan mirror 37, and the processed surface is irradiated with the laser beam by line scanning. Irradiate with a two-dimensional scan. A range in which the line scan or two-dimensional scan is performed is a laser irradiation range 24.

Note that two or more scan mirrors may be provided, and a laser beam may be irradiated to the processing surface by line scanning or two-dimensional scanning by reciprocating oscillation of each scanning mirror.
Further, the scan mirror 37 reflects infrared rays emitted or reflected from the temperature observation region 25 while reciprocally swinging, and returns the infrared rays to the clad portion 33 of the optical fiber 11 via the scan mirror 37.

  In the fifth embodiment, an optical system that receives light emitted or reflected from the temperature observation region 25 and guides infrared light other than light having the wavelength of the laser light to the light receiving surface 10 of the infrared sensor 9 is folded back with the scan mirror 37. A mirror 36 and a condenser lens 35 are included.

Note that the light transmitted through the scan mirror 37 enters the camera 18 via the condenser lens 8 and the laser light cut filter 17.
(Embodiment 7)
FIG. 13 shows the configuration of the laser heating apparatus according to the seventh embodiment. However, the same members as those described based on FIGS. 1 and 8 to 12 are denoted by the same reference numerals, and description thereof is omitted.

  In FIG. 13, the scan mirror 39 is provided with a thin film filter or thin film coat that transmits infrared light but reflects light having a wavelength of laser light. Similarly to the sixth embodiment, the scan mirror 39 reflects the laser light from the collimating lens 12 while reciprocally swinging by a predetermined angle about the rotation shaft 38.

  Infrared light except the light having the wavelength of the laser light emitted from the temperature observation region 25 passes through the scan mirror 39, and the laser light cut filter 6 and visible light are collected by the condenser lens 8 as in the second embodiment. The light is guided to the light receiving surface 10 of the infrared sensor 9 through the cut filter 7.

  In the seventh embodiment, an optical system that receives light emitted or reflected from the temperature observation region 25 and guides infrared light other than light having the wavelength of the laser light to the light receiving surface 10 of the infrared sensor 9 includes a scan mirror 39 and a laser. The light cut filter 6, the visible light cut filter 7, and the condenser lens 8 are included.

As described above, the laser heating device according to the seventh embodiment can continuously monitor the amount of infrared rays emitted from the entire temperature observation region 25.
(Embodiment 8)
The laser heating apparatus according to the eighth embodiment described above is that the processing surface is irradiated with the laser light itself emitted from the LD element (laser diode) included in the laser emitting unit without using an optical fiber. Different from ~ 7.

  Hereinafter, the laser heating apparatus according to the eighth embodiment will be described with respect to the differences from the first to seventh embodiments. However, the description of the same parts as those in the first to seventh embodiments is omitted.

  FIG. 14 shows the configuration of the laser heating apparatus according to the eighth embodiment. However, FIG. 14A is a side view when the laser heating device is viewed from the SLOW direction of the laser light, and FIG. 14B is a side view when the laser heating device is viewed from the direction orthogonal to the SLOW direction of the laser light. FIG. Moreover, the same code | symbol is attached | subjected to the member same as the member demonstrated based on FIG. 1, 8-13, and description is abbreviate | omitted.

  14A and 14B, the LD element 40 emits a laser beam having a constant wavelength. Here, a single-chip single emitter is used as the LD element. The cylindrical lens 41 is disposed in a direction that suppresses the spread of the laser light emitted from the LD element 40 in the FAST direction. The cylindrical lens 41 makes the FAST direction of the laser light emitted from the LD element 40 parallel or low spread.

  The half mirror 13 reflects the laser light 42 from the cylindrical lens 41. The condensing lens 2 condenses the laser light from the half mirror 13. Due to the cylindrical lens 41 and the condensing lens, the shape of the laser beam formed on the processed surface is rectangular or the like.

  As described above, in the eighth embodiment, the cylindrical lens 41 and the condenser lens 2 are provided as an optical system for making the laser irradiation range on the processing surface rectangular or elliptical. That is, after the spread of the laser light emitted from the LD element 40 in the FAST direction is suppressed by the cylindrical lens 41, the laser light is condensed by the condenser lens 2, and the shape of the laser light formed on the processing surface is changed to a rectangular shape or the like. To do.

(Embodiment 9)
The laser heating apparatus according to the ninth embodiment is that the shape of the laser beam formed on the processed surface is made rectangular by using two LD elements (laser diodes) without using a condenser lens. This is different from the eighth embodiment.

  Hereinafter, the laser heating apparatus according to the ninth embodiment will be described with respect to parts different from those of the first to eighth embodiments. However, description of the same parts as those in the first to eighth embodiments will be omitted.

  FIG. 15 shows the configuration of the laser heating apparatus according to the ninth embodiment. However, FIG. 15A is a side view when the laser heating device is viewed from the SLOW direction of the laser light. FIG. 15B is a side view when the laser heating device is viewed from a direction orthogonal to the SLOW direction of the laser light, and shows the half mirror 13 and the collimating lens 43 extracted. Moreover, the same code | symbol is attached | subjected to the member same as the member demonstrated based on FIG. 1, 8-13, and description is abbreviate | omitted.

  In FIG. 15 (a), the laser emitting unit includes two LD elements 40 and a heat sink 45. The heat sink 45 is made of, for example, copper. The two LD elements 40 are bonded to the heat sink 45. As shown in FIGS. 15A and 15B, the two LD elements 40 are the same at a predetermined interval d so that the laser light is emitted from the end face of the heat sink 45 in the same direction and parallel to the optical axis. Arranged on a plane.

  The collimating lens 43 is arranged in a direction that suppresses the spread of the laser light emitted from the LD element 40 in the FAST direction. The collimating lens 43 makes the FAST direction of the laser light emitted from the LD element 40 parallel or low. The half mirror 13 reflects the laser light 44 from the collimating lens 43.

  In this way, when two LD elements are arranged on the same plane at a predetermined interval d and the laser light is emitted in the same direction and parallel to the optical axis, the LD element 40 (the emission end of the collimating lens 43). ) To the processing surface 46, the laser power density distribution in the SLOW direction on the processing surface 46 can be trapezoidal. Alternatively, the temperature distribution in the SLOW direction on the processed surface 46 can be trapezoidal. This is due to the following reason.

  In FIG. 16, the distances from the exit end of the collimating lens 43 to the processed surface 46 when the processed surface 46 is at each of positions A, B, and C are WDA, WDB, and WDC. In addition, the half-value laser power densities in the SLOW direction on the processed surface 46 when the processed surface 46 is at positions A, B, and C are PA, PB, and PC, respectively. Further, the temperature distributions in the SLOW direction on the processed surface 46 when the processed surface 46 is at positions A, B, and C are TA, TB, and TC, respectively.

  As shown in FIG. 16A, two laser beams are emitted from the end face of the heat sink 45 in the same optical axis direction at a predetermined spread angle in the SLOW direction (X direction). The FAST direction of the laser light (perpendicular to the paper surface in FIG. 16) is made parallel or low spread by the collimating lens 43.

  Here, when the processing surface 46 moves away from the position A to the position B, the laser power density distribution is two trapezoidal power distributions at the position A as shown in FIG. have a finger in the pie. As a result, at position B, the power at the center is low, but the temperature density distribution is uniform.

  This trapezoidal (TOP HAT-shaped) temperature density distribution is extremely effective for FPIC, FPC, and line-shaped resin bonding, and since the temperature density distribution is homogeneous, it reduces the occurrence of burns and damage in the center, and improves the thermal bonding quality. Can be improved.

  Further, when the processed surface 46 reaches the position C, the laser power density distribution becomes trapezoidal (TOP HAT shape) as shown in FIG. When the laser power density distribution has a trapezoidal shape, the temperature gradient during heating increases at the center. However, when the laser beam irradiation time is short, uniform heating can be performed without being affected by the difference in temperature gradient.

  In the ninth embodiment, the spread of the two laser beams emitted from the two LD elements (laser diodes) in the FAST direction is suppressed, and the laser irradiation range is rectangular by the two laser beams that suppress the spread. An optical system for equalizing is configured by a collimating lens.

  A cylindrical lens may be used in place of the collimating lens 43. Two or more collimating lenses 43 may be provided. Further, the number of LD elements may be two or more.

(Embodiment 10)
The laser heating apparatus according to the tenth embodiment is different from the above-described ninth embodiment in that the laser emission unit includes a collimator lens, an infrared sensor, a laser light cut filter, and a condenser lens. Hereinafter, the laser emission part of the laser heating apparatus according to the tenth embodiment will be described with reference to the drawings.

  FIG. 17A shows a top view of the laser emitting portion in the tenth embodiment. FIG. 17B is a front view of the laser emitting portion in the tenth embodiment. FIG. 17C is a top view of the laser emitting unit in Embodiment 10 with the upper lid removed. FIG. 17D shows the shape of the laser beam formed on the processed surface in the tenth embodiment. FIG. 17E shows a perspective side view of the laser emitting portion in the tenth embodiment. FIG. 17F shows the shape of the laser beam formed on the processed surface in the tenth embodiment. However, the same members as those described based on FIGS. 1 and 8 to 16 are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 17, the laser emitting unit 1 includes a holder 47 and an upper lid 48 of the holder 47. Inside the holder 47, a heat sink 45 in which two LD elements 40 are joined is installed. The heat sink 45 incorporates a laser light cut filter 6, a condenser lens 8, an infrared sensor 9, and the like.

In addition, movable bodies 50 and 51 are installed inside the holder 47. Although not shown, support portions for supporting the upper movable body 50 are provided on both side surfaces inside the holder 47.
On the lower surface side of the upper movable body 50, a lower movable body 51 having a length and width smaller than those of the upper movable body 50 is fixed by two screws 49. The lower movable body 51 moves in a seesaw shape with the protrusion 52 as a fulcrum by the tightening amount of the two screws 49. A collimator lens 43 is bonded to the lower movable body 51 so as to be positioned in front of the laser emission end face of the LD element 40. As described above, the laser emitting unit 1 is configured such that the fixing position of the collimating lens 43 can be adjusted in the vertical direction with respect to the laser emitting end face of the LD element 40. Therefore, according to the laser emission part 1, the position of the laser irradiation range 24 can be changed arbitrarily. The protrusion 52 may be provided on either the upper movable body 50 or the lower movable body 51.

The length of the upper movable body 50 in the front-rear direction is shorter than the length of the holder 47 in the front-rear direction, and there is a gap between the upper movable body 50 and the front and rear end surfaces of the holder 47. Three screws 53 protruding from the front and rear end surfaces inside the holder 47 abut on the front and rear end surfaces of the upper movable body 50. Therefore, the upper movable body 50 moves in the front-rear direction of the holder 47 by the tightening amount of the three screws 53 . Therefore, the fixing position of the collimating lens 43 can be adjusted in the front-rear direction of the holder 47 by the three screws 53 . As described above, the laser emitting unit 1 is configured such that the fixing position of the collimating lens 43 can be adjusted in the front-rear direction with respect to the laser emitting end face of the LD element 40. Note that the number of screws 53 is not limited to three.

  Therefore, according to the laser emitting unit 1, the aspect ratio of the shape (laser irradiation range) of the laser beam formed on the processed surface 46 can be arbitrarily changed. For example, as shown in FIG. 17F, the aspect ratio of the laser irradiation range 24 can be changed from the laser irradiation range 24 indicated by a solid line to the laser irradiation range 24 indicated by a broken line.

  Furthermore, according to the laser emitting unit 1, the distance from the emitting end of the collimating lens 43 to the processing surface 46 can be adjusted, and the laser power density distribution in the SLOW direction on the processing surface 46 can be trapezoidal. . Alternatively, the temperature distribution in the SLOW direction on the processed surface 46 can be trapezoidal.

  Further, as shown in FIG. 17, the laser emitting unit 1 includes a laser light cut filter 6, a condenser lens 8, and an infrared sensor 9, and is configured to detect infrared rays emitted from the temperature observation region. . The condenser lens 8 is bonded to a lens holder that can adjust the distance to the light receiving surface 10 of the infrared sensor 9. Therefore, according to the laser emitting unit 1, the size of the temperature observation area can be arbitrarily changed. For example, as shown in FIG. 17F, the temperature observation area 25 can be changed from the temperature observation area 25 indicated by a solid line to the temperature observation area 25 indicated by a broken line.

In the tenth embodiment, a collimator lens 43 is provided as a lens for suppressing the spread of the laser light emitted from the LD element in the FAST direction. Further, a screw 49, a movable body 50, 51, a protrusion 52, and a screw 53 are provided as an adjusting mechanism to which the collimating lens 43 is bonded and can adjust the position of the collimating lens 43 with respect to the laser emission end face of the LD element.

  A cylindrical lens may be used in place of the collimating lens 43. Two or more collimating lenses 43 may be provided. Further, the number of LD elements may be two or more.

(Embodiment 11)
If an attempt is made to amplify nW class infrared light to an mV class signal level at which a normal control circuit operates, a high gain amplifier is required as a preamplifier for amplifying the output signal level of the infrared sensor. However, no matter how a high-grade operational amplifier is used as a high gain amplifier or an operational amplifier having a temperature compensation function, the output of the amplifier greatly changes in drift.

  In each of the above embodiments 1 to 10, the temperature is measured by obtaining in advance a relational expression of a calibration value (calibration value) between the output signal level of the infrared sensor or the output signal level of the preamplifier and the actually measured temperature. Yes. However, since the environment changes between the master temperature measurement and the actual laser heating / processing, there is a possibility that accurate temperature measurement cannot be performed only with the relational expression.

  Further, since the laser beam itself is infrared and the power of the laser beam for processing such as soldering is as strong as the W class, even if a laser beam cut filter is provided, an infrared ray capable of detecting a weak nW class infrared ray. Laser light affects the sensor as disturbance light.

  Therefore, in the eleventh embodiment, the amount of change in the output signal level of the infrared sensor immediately after laser irradiation is monitored, and it is determined whether or not the amount of change is larger than a preset amount of change. It is determined whether the output signal level of the sensor (corresponding to the temperature of the object to be heated) has reached the set temperature Ts. When the amount of change in the output signal level of the infrared sensor reaches the set amount of change, the emission of the laser beam is stopped or the laser beam is emitted intermittently with a predetermined laser power.

  The configuration of the laser heating apparatus in the eleventh embodiment is the same as that in the fourth to tenth embodiments. Here, the configuration of the laser heating apparatus in Embodiment 4 will be described as an example (see FIG. 10).

  FIG. 18A shows a graph of laser power P of laser light and elapsed time t. FIG. 18B shows a graph of the output signal level of the preamplifier 14 and the elapsed time t. FIG. 18C shows a graph of the difference between the output signal level of the preamplifier 14 and the elapsed time t based on the output signal level of the preamplifier 14 at time t0 after the lapse of Δt from the laser irradiation start time ts.

  In FIG. 18B, the solid line indicates the actual output signal level of the preamplifier 14 including the temperature draft and the amount of laser beam leakage detected. A dotted line indicates an ideal output signal level of the preamplifier 14 that does not include the temperature draft and the leak detection of the laser beam. In FIGS. 18A and 18B, t1 indicates the time for the actual output signal level of the preamplifier 14 to reach the level PDs (corresponding to the set temperature Ts). Further, t2 indicates the time for the ideal output signal level of the preamplifier 14 to reach the level PDs.

  As shown in FIGS. 18A and 18B, when the laser beam having the laser power Ps is irradiated from the time ts, the output signal level of the preamplifier 14 at the laser irradiation start time ts includes the temperature drift ΔPD and the laser. The amount of detected light leak ΔPDL is included and becomes larger than the ideal output signal level of the preamplifier 14. For this reason, even if an attempt is made to stop the oscillation of the laser beam when the output signal level of the preamplifier 14 reaches the level PDs (time t1), the time t1 is the time t2 when the output signal level of the ideal preamplifier 14 reaches the level PDs. It is off.

  Therefore, in the laser heating apparatus according to the eleventh embodiment, as shown in FIG. 18C, the control unit 30 uses the output signal level of the preamplifier 14 at time t0 after the lapse of Δt from the laser irradiation start time ts as a reference. When the difference level ΔPD of the output signal level of the preamplifier 14 reaches the set change amount ΔPDs, the laser beam is stopped. The control unit 30 sets the set change amount ΔPDs based on the signal level generated by the volume 29.

  The difference level ΔPD is not affected by temperature drift, laser light leak detection, or the difference in the level of the laser power Ps, and the period until the difference level ΔPD reaches the set change amount ΔPDs from the 0 level (time t3). ) Is a fixed time, and laser irradiation can be stably stopped.

  In addition to stopping the laser irradiation, as shown in FIG. 19, laser oscillation may be intermittently performed with a predetermined laser power equal to or lower than the laser power Ps with reference to the set change amount ΔPDs (see FIG. 19). Chopping operation).

  As described above, the laser heating apparatus according to the eleventh embodiment can stably operate with good reproducibility by canceling the leak detection of laser light and the temperature drift of the infrared sensor or the preamplifier.

  Also, since the PIN photodiode has a large dynamic range, an infrared detection signal (preamplifier) that does not include errors such as temperature drift is monitored by monitoring the amount of change in the output signal level of the preamplifier even when there is a large disturbance light due to the laser beam. Output signal). Therefore, the laser heating device can stably control the temperature of the object to be heated.

Laser heating equipment according to the present invention, temperature changes and scorching during melting, such that by detecting the signs become abnormal heat generated solder or resin in a machining point, the peripheral portion is not burnt soldering or resin scorching For example, it is useful for performing laser heating and processing such as soldering, resin bonding, resin marking, and welding with a laser beam emitted from a semiconductor laser.

It is a figure which shows the structure of the laser heating apparatus in Embodiment 1 of this invention. It is a figure which shows the spectral sensitivity characteristic of the InGaAs PIN photodiode in Embodiment 1 of this invention. It is a figure which shows the infrared absorption characteristic of optical component material. It is a figure which shows the spectral radiance characteristic of the infrared rays radiated | emitted from a black body. It is a figure which shows the practical radiance which the InGaAs PIN photodiode in Embodiment 1 of this invention detects (when the temperature of a process point is 227 degreeC). It is a figure which shows the practical radiance which the InGaAs PIN photodiode in Embodiment 1 of this invention detects (when the temperature of a process point is 127 degreeC). It is a figure which shows the practical radiance which the InGaAs PIN photodiode in Embodiment 1 of this invention detects (when the temperature of a process point is 327 degreeC). It is a figure which shows the structure of the laser heating apparatus in Embodiment 2 of this invention. It is a figure which shows the structure of the laser heating apparatus in Embodiment 3 of this invention. It is a figure which shows the structure of the laser heating apparatus in Embodiment 4 of this invention. It is a figure which shows the structure of the laser heating apparatus in Embodiment 5 of this invention. It is a figure which shows the structure of the laser heating apparatus in Embodiment 6 of this invention. It is a figure which shows the structure of the laser heating apparatus in Embodiment 7 of this invention. It is a figure which shows the structure of the laser heating apparatus in Embodiment 8 of this invention. It is a figure which shows the structure of the laser heating apparatus in Embodiment 9 of this invention. It is a figure for demonstrating the shape (laser irradiation range) of the laser beam which the laser heating apparatus in Embodiment 9 of this invention forms in a process surface. It is a block diagram which shows a specific example of the laser emission part with which the laser heating apparatus in Embodiment 10 of this invention is provided. It is a figure for demonstrating the laser power control of the laser heating apparatus in Embodiment 11 of this invention. It is a figure for demonstrating the laser power control of the laser heating apparatus in Embodiment 11 of this invention.

Explanation of symbols

1 laser emitting unit 2 condenser lens 3 solder 4 printed circuit board 5 lands 6 the laser beam cut filter 7 visible light cut filter 8 converging lens 9 IR sensor 10 receiving surface 11 optical fiber 12 collimating lens 13 half mirror 14 preamplifier 15 meter 16 Hot mirror 17 Laser light cut filter 18 Camera 19 Aperture 20 Optical path axis 21 Processing point detection field of view 22 Cylindrical lens 23 FPIC
24 Laser irradiation range 25 Temperature observation area 26 Folding mirror 27 Laser control device 28 Temperature level conversion circuit 29 Volume 30 Control unit 31 Core part 32 Clad part 33 Folding mirror 34 LD element 35 Condensing lens 36 Folding mirror 37 Scan mirror 38 Rotating shaft 39 Scan Mirror 40 LD Element 41 Cylindrical Lens 42 Laser Light 43 Collimating Lens 44 Laser Light 45 Heat Sink 46 Processing Surface 47 Holder 48 Upper Cover 49 Screw 50 Upper Movable Body 51 Lower Movable Body 52 Projection

Claims (1)

A laser emitting section for emitting laser light to be irradiated on the object to be heated;
An infrared sensor that generates a signal based on the integrated value of the infrared spectral radiance received by the light-receiving surface;
An imaging device for imaging visible light;
Including a mirror that receives the laser light, emits the received laser light toward the object to be heated, and receives light emitted or reflected from the object to be heated and its peripheral part; Of the light emitted or reflected from the object to be heated and its peripheral part and received by the mirror, the infrared light except the light having the wavelength of the laser light is guided to the light receiving surface of the infrared sensor, and the visible light is imaged. An optical system leading to the device;
A storage unit for storing in advance a relational expression of a calibration value between the level of the signal generated by the infrared sensor and the actual temperature of the object to be heated;
A temperature measuring unit that calculates the temperature of the object to be heated based on the signal generated by the infrared sensor and the relational expression;
Equipped with a,
The laser emitting part is
Two or more laser diodes emitting the laser beam;
A lens for suppressing the spread of each laser beam emitted from each laser diode in the FAST direction;
An adjustment mechanism capable of adjusting the position of the lens with respect to the laser emission end face of each laser diode so that a part of the laser power density distribution in the SLOW direction of each laser beam interferes on the processing surface; ,
The laser heating device is characterized in that the laser irradiation range on the processing surface is made rectangular or elliptical by each laser beam from the lens .

Images