JP5821329B2 - Laser processing equipment - Google Patents

Description

  The present invention relates to a laser processing apparatus used for the purpose of marking patterns such as characters and figures, and performing processing such as drilling, cutting, and trimming.

  As a conventional laser processing device, invisible laser light separated by a dichroic mirror is emitted as a processing beam, and the other light separated by the dichroic mirror is received by a light receiving element, and the amount of light received is processed. There is information to be used as information representing the strength of the. Further, in this type of laser processing apparatus, by emitting guide light by visible light along the optical path of the processing beam, it is possible to confirm the irradiation position and direction of the processing beam that cannot be directly recognized. Yes.

  For example, in Patent Document 1, a mirror body in which a beam splitter and a dichroic mirror are integrated is provided on the optical axis of a laser light source that emits invisible laser light, and a position corresponding to the same axis as the laser light source is provided via this mirror body. An apparatus having a configuration in which a visible laser light source is provided and measurement light by invisible laser light transmitted through a dichroic mirror and guide light by visible laser light reflected by a dichroic mirror is emitted to the outside is disclosed.

  Patent Document 1 also describes that a light receiving element (photodiode) for obtaining a reference signal for invisible laser light is provided on an optical path branched by a mirror. Further, the invisible laser light is converted into light having two orthogonal polarization components, the visible laser light is converted into linearly polarized light, and the polarizing plate for blocking the polarization component of the visible laser light between the light receiving element and the dichroic mirror. It is described that the quality of the reference signal is secured by preventing the component representing the intensity of the guide light from being incident on the light receiving element by arranging.

  In Patent Document 2, a laser light source for processing and a visible light source for guide light are mixed with an optical axis via a mixing mirror (which is considered to be a dichroic mirror that transmits light in a wavelength region including the visible light region). A configuration in which the processing beam reflected by the mixing mirror and the visible guide light transmitted through the mixing mirror are emitted to the outside while a light receiving element is provided in the optical path of the light transmitted from the laser light source through the mixing mirror. Are described.

JP 2000-16951 A JP 2007-61843 A

  In recent years, laser processing apparatuses configured to guide laser light from a laser light source to a head unit via an optical fiber have become widespread. In this type of laser processing apparatus, amplification is performed while the laser light passes through the optical fiber. The polarization characteristic (intensity ratio between the P wave and the S wave) of the laser light varies depending on the action and the like. In addition, when the optical fiber is moved, the polarization characteristics of the laser light entering the head portion change, so it is difficult to adopt the configuration described in Patent Document 1. This is because if the polarization characteristics of the laser light entering the head portion change, the intensity of light that passes through the polarizing plate and enters the light receiving element also fluctuates, and the accuracy of the received light amount signal cannot be ensured.

  In the invention described in Patent Document 2, since all the light from the visible light source passes through the dichroic mirror and is emitted as guide light, there is no possibility that the visible light is directed toward the light receiving element, and a polarizing plate is not used. In both cases, a received light amount signal from which the influence of the guide light is excluded can be obtained. However, when the difference between the P-wave transmittance and the S-wave transmittance at the dichroic mirror increases, the ratio of each polarization component in the light that passes through the mirror and enters the light-receiving element, and is output as a processing beam. It will be in the state from which the ratio of each polarization component in reflected light differs. For this reason, when the configuration shown in Patent Document 2 is introduced as it is into an optical fiber type laser processing apparatus, it becomes difficult to correctly recognize the change when the polarization characteristic of the laser light from the optical fiber changes. .

  For example, when the transmittance of the P wave of the dichroic mirror greatly exceeds the transmittance of the S wave, if the intensity of the P wave of the laser light from the optical fiber is significantly reduced, the P in the reflected light that becomes the processing beam The intensity of the wave is similarly reduced, and the intensity of the entire processing beam is also reduced. However, the degree of decrease of the P wave in the transmitted light for monitoring becomes relatively gradual, and the decrease in the intensity of the entire transmitted light is also reduced, so that it may not be possible to correctly recognize that the intensity of the processing beam has decreased. . Further, when the intensity of the S wave of the laser light from the optical fiber is significantly increased, the intensity of the S wave in the reflected light that becomes the processing beam is also increased, and the intensity of the entire processing beam is also increased. However, there is a possibility that the increase in the intensity of the S wave of the transmitted light for monitoring does not increase so much, and therefore it may not be possible to correctly recognize that the intensity of the processing beam has been increased.

  The present invention pays attention to the above-mentioned problems, and an object of the present invention is to make it possible to acquire a received light amount signal that accurately represents the intensity of a processing beam and its change.

In the present invention, laser light from a laser light source is guided to a head portion including a dichroic mirror through an optical fiber, and the laser light reflected by the dichroic mirror is emitted to the outside as a processing beam from the head portion , and the dichroic mirror This is applied to a laser processing apparatus having a configuration in which a light receiving element for monitoring the intensity of a processing beam is provided in the optical path of a laser beam that passes through . In the present invention, the dichroic mirror equalizes the polarization characteristics in the reflected light of the laser light and the polarization characteristics in the transmitted light of the laser light, and transmits the laser light with a ratio exceeding the degree of increase or decrease of the transmitted light amount corresponding to the error. Manufactured according to the design . An optical attenuation filter is provided between the dichroic mirror and the light receiving element.

In the above configuration, it is desirable to use a dichroic mirror designed so that the ratio of the transmittance of the P wave and the S wave (which may be paraphrased as reflectance. The same applies hereinafter) is 1. According to the mirror having such characteristics, the intensity ratio of each polarization component in the reflected light and the intensity ratio of each polarization component in the transmitted light can be made substantially the same. Therefore, it is possible to transmit the light contained in the same ratio as in the processing beam by the laser beam reflected by the dichroic mirror from the dichroic mirror and guide it to the light receiving element.
This relationship is maintained even if the polarization characteristics of the laser beam entering the head unit from the optical fiber fluctuate, so if the polarization characteristics of the processing beam change, the same change occurs in the monitoring light. The same applies to the change in the intensity of the entire light. Therefore, the accuracy of the monitoring light can be ensured.

  However, the actual characteristics of the dichroic mirror are not as designed, and an error occurs in the amount of light transmitted from the dichroic mirror due to variations in the structure of the dielectric layer. Since the error in the amount of transmitted light may vary depending on the polarization component, a difference occurs in the transmittance of each polarization component. For this reason, when the ratio of the light separated as the monitor light is reduced, an error in the amount of transmitted light greatly affects the transmittance, and the difference in transmittance between the polarization components increases. When this happens, the difference between the polarization characteristics of the monitoring light and the polarization characteristics of the processing beam increases, and the accuracy of the monitoring light decreases.

  On the other hand, when the ratio of the light separated as the monitoring light is increased, the influence of the transmitted light amount error on the transmittance is reduced, so that the difference in transmittance between the polarization components can be kept within an allowable range. However, since the intensity of the monitoring light is increased, the light receiving element that receives the light may be saturated.

Regarding the above problem, in the present invention, since the light attenuation filter is provided between the dichroic mirror and the light receiving element, the difference in transmittance of each polarization component between the monitoring light and the processing beam is within an allowable range. The transmittance of the dichroic mirror is increased so as to be within the range (for example, when an error corresponding to 1% of the entire laser beam irradiated to the mirror can occur in the transmission amount from the dichroic mirror, the transmission of the dichroic mirror The rate can be 5%.) The light can be attenuated by the light attenuation filter to such an extent that the light receiving element is not saturated, and guided to the light receiving element. This makes it possible to stably acquire a received light amount signal that accurately represents the intensity of the processing beam from the light receiving element.

In one embodiment of the above laser processing apparatus, a visible light source in which the optical axis is aligned with the optical path of the reflected light from the dichroic mirror with respect to the laser light via the dichroic mirror is provided. The dichroic mirror has a characteristic of transmitting a part of the wavelength range of laser light emitted from the laser light source and visible light emitted from the visible light source.

  According to the above configuration, the laser light emitted from the laser light source and reflected by the dichroic mirror is emitted as a processing beam, and the visible light emitted from the visible light source and transmitted through the dichroic mirror is emitted along the processing beam. The Thereby, the light from a visible light source can be functioned as guide light. In addition, the laser light emitted from the laser light source and transmitted through the dichroic mirror functions as monitoring light. However, since most of the light from the visible light source passes through the dichroic mirror, it is reflected by the dichroic mirror and used for monitoring. There is no possibility that visible light traveling along the optical path of the light affects the monitor light.

When a reflective attenuator is used as the light attenuating filter, the reflective attenuator is deployed with the reflecting surface inclined with respect to the direction orthogonal to the optical path of the laser light that passes through the dichroic mirror, Due to the inclination, it is desirable to reflect the laser light transmitted from the laser light source through the dichroic mirror in a direction that does not become light traveling toward the visible light source.
In one embodiment in which a reflection type attenuator is used, a first light guide for guiding laser light emitted from a laser light source and transmitted through a dichroic mirror to a light receiving element and visible light emitted from a visible light source are applied to the head unit. A second light guide for guiding to the dichroic mirror is provided, and both light guides communicate with each other at a place corresponding to the dichroic mirror. The reflection type attenuator is disposed in an inclined posture in the first light guide, and reflects the laser light transmitted from the laser light source through the dichroic mirror in a direction that does not become light traveling toward the visible light source. .
The “light traveling toward the visible light source” includes the light directly entering the second light guide from the reflective attenuator and traveling toward the visible light source, and after entering the dichroic mirror from the reflective attenuator. Light that is reflected by the mirror and enters the second light guide path and travels toward the visible light source is included.

  According to the above configuration, the monitoring light from the dichroic mirror through the reflective attenuator to the light receiving element and the guide light from the visible light source to the dichroic mirror can be stably guided by the light guide path. . The attitude of the reflection type attenuator is adjusted so that the laser beam reflected by the reflection type attenuator is reflected instead of the light traveling toward the visible light source. The visible light source can be prevented from being destroyed.

  In one embodiment according to the above-described reflection type attenuator, the reflection type attenuator is provided with a posture to reflect the laser beam transmitted from the laser light source through the dichroic mirror to the wall surface in the first light guide. In another embodiment, the reflection type attenuator is provided with a posture for reflecting the laser light transmitted from the laser light source through the dichroic mirror to the wall surface in the second light guide.

  In each embodiment, if the wall surface of the light guide that guides the reflected light from the reflective attenuator is processed to absorb or diffuse the reflected light from the reflective attenuator, the laser guided to the wall surface Since light can be absorbed or diffused by the wall surface, the laser light reflected by the reflective attenuator can be more reliably prevented from being guided to the visible light source.

According to the present invention, light having a polarization characteristic equivalent to that of the laser beam reflected by the dichroic mirror is transmitted from the dichroic mirror, and the transmitted light is set to an intensity that does not saturate the light receiving element. Can lead. Therefore, based on the received light amount signal obtained by the light receiving element, it is possible to accurately recognize the intensity of the processing beam and the change state thereof.

It is a figure which shows the structure of the laser processing apparatus concerning one Example of this invention. It is a figure which shows the structure of the head part concerning a 1st modification. FIG. 4 is a diagram illustrating another optical path of reflected light from a reflection type attenuator with respect to the head unit having the same configuration as in FIG. 2. It is a figure which shows the structure of the head part concerning a 2nd modification.

FIG. 1 shows a configuration example of a laser processing apparatus to which the present invention is applied.
The laser processing apparatus of this embodiment includes a controller 1 including a laser light source 10, a head unit 2 that processes laser light from the laser light source 10 and emits a processing beam, and light that connects the controller 1 and the head unit 2. Fiber 3. In addition to the laser light source 10, the controller 1 is provided with a control circuit 11 including a computer, a light receiving circuit 12, a display unit 13, and the like.

  The head unit 2 includes an optical unit 20, an isolator 21, a pair of galvanometer mirrors 26A and 26B, a condenser lens 27, and the like. The optical unit 20 has a configuration in which a dichroic mirror 22, a photodiode 23, a light attenuating filter 24, and a laser diode 25 are fixed to a support member 200 having light guide paths 201 and 202 communicated in an L shape. The support member 200 is made of aluminum, and a light absorption film (not shown in FIG. 1) made of black alumite or the like is formed on the wall surfaces of the light guide paths 201 and 202. The photodiode 23 is electrically connected to the light receiving circuit 12 of the controller 1.

The laser light source 10 includes an oscillation element that emits light in the infrared region. The control circuit 11 controls the light emission operation and the light emission intensity of the laser light source 10.
Infrared laser light emitted from the laser light source 10 is amplified in the optical fiber 3 and guided to the isolator 21 in the head unit 2. The isolator 21 prevents the infrared laser light from returning to the optical fiber 3 and advances the infrared laser light toward the optical unit 20.

  The dichroic mirror 22 is disposed on the optical path of the infrared laser light emitted from the isolator 21 with a mirror surface inclined by 45 degrees with respect to the central axis of the optical path. The light attenuating filter 24 and the photodiode 23 are disposed in the optical path of the infrared laser light transmitted from the dichroic mirror 22.

  The laser diode 25 emits visible laser light, and is disposed in a state where the optical axis is aligned with the reflected optical path of the infrared laser light via the dichroic mirror 22. Visible laser light emitted from the laser diode 25 travels through the light guide 201 and is guided to the dichroic mirror 22.

  The dichroic mirror 22 has a characteristic of transmitting light in a wavelength region corresponding to about 5% in the infrared light region and visible light, and reflecting light in other wavelength regions. The dichroic mirror 22 is designed so that the polarization transmittance ratio is approximately 1.0. The polarization transmittance ratio is the ratio (Tp / Ts) of the P-wave transmittance Tp to the S-wave transmittance Ts.

  According to the dichroic mirror 22 having the above characteristics, a part of the infrared laser light guided to the dichroic mirror 22 through the optical fiber 3 and the isolator 21 is transmitted through the dichroic mirror 22, and the remaining infrared laser light is The light is reflected by the dichroic mirror 22 and guided to the galvano mirror 26A. The galvano mirror 26A and the other galvanometer mirror 26B determine the irradiation position and irradiation direction of the infrared laser light. The infrared laser light that has passed through the galvanometer mirrors 26A and 26B is narrowed down by the condenser lens 27 and is emitted to the outside as a processing beam.

  Although not shown in FIG. 1, the galvanometer mirrors 26A and 26B are electrically connected to the control circuit 11 of the controller 1, and the rotation direction and amount of rotation of the motors of the mirrors 26A and 26B are determined by signals from the control circuit 11. Be controlled.

  The visible laser light emitted from the laser diode 25 passes through the dichroic mirror 22, follows the same optical path as the infrared laser light reflected by the mirror 22, and is emitted to the outside as guide light.

The light guide path 202 is for guiding the infrared laser light transmitted through the dichroic mirror 22 to the photodiode 23, and the light attenuation filter 24 is provided between them.
In this embodiment, a reflection type attenuator is used as the light attenuation filter 24. The reflection type attenuator 24 is disposed in the light guide path 202 with a sufficient distance from the communication position with the other light guide path 201 with the reflecting surface facing the wall surface on the communication side to the light guide path 201. . A plurality of V-shaped grooves 204 are formed along the circumferential direction on the wall surface of the light guide path 202 at least in the range from the communication position to the light guide path 201 to the arrangement position of the reflective attenuator 24. . The light absorption film described above is also formed in the V-shaped groove 204 and its periphery.

The infrared laser light transmitted through the dichroic mirror 22 is guided to the reflection type attenuator 24, and a part of the infrared laser light is transmitted through the reflection type attenuator 24 and enters the photodiode 23. The remaining infrared laser light is reflected by the mirror in the reflection type attenuator 24, but the mirror is tilted so that the direction of reflection is directed to the wall surface where the V-shaped groove 204 is formed. Most of the infrared laser light thus applied is irradiated and diffused in the formation range of the V-shaped groove 204 and is absorbed by the light absorption film. Further, a part of the infrared laser light reflected by the reflection type attenuator 24 is incident on a place away from the center of the dichroic mirror 22 and is reflected toward the wall surface of the light guide 201 (dotted line in FIG. 3 described later). However, since the light absorption film is also formed on the wall surface of the light guide path 201, the infrared laser light that follows this path is also absorbed by the light absorption film.
Therefore, it is possible to prevent the infrared laser light reflected by the light attenuation filter 24 from returning to the dichroic mirror 22 and reflecting toward the laser diode 25.

  The received light amount signal from the photodiode 23 that has received the infrared laser light that has passed through the light attenuation filter 24 is input to the light receiving circuit 12 of the controller 1. The light receiving circuit 12 includes a circuit for amplifying the received light amount signal and an A / D conversion circuit for digital conversion. The control circuit 11 inputs the received light amount signal after the digital conversion, and displays the received light amount indicated by the signal on the display unit 13. Further, the light emission intensity of the laser light source 10 is adjusted based on the received light amount indicated by the received light amount signal, or an error notification is executed by the display unit 13 or the like when the received light amount significantly decreases.

The dichroic mirror 22 of this embodiment is manufactured based on a design in which the polarization transmittance ratio is about 1.0 and the transmittance for light in the infrared light region is about 5%. By using the dichroic mirror 22 and the light attenuating filter 24 having this characteristic, the received light amount signal output from the photodiode 23 can accurately indicate the intensity of the processing beam. Hereinafter, the reason will be described in detail.
In the following description, infrared laser light transmitted through the dichroic mirror 22 and the optical attenuation filter 24 is referred to as “transmitted laser light”, and infrared laser light reflected by the dichroic mirror 22 is referred to as “reflected laser light”.

First, in the dichroic mirror 22 as designed, the transmittance of the P wave and the transmittance of the S wave are equal, so the ratio of the P wave and the S wave in the transmitted laser beam is the ratio of the P wave and the S wave in the reflected laser beam. It is considered that the ratio is almost the same. Thereby, the intensity of the transmitted laser beam correctly represents the intensity of the reflected laser beam.
Even if the polarization characteristic (intensity ratio between P wave and S wave) of the infrared laser beam entering the head unit 2 is changed due to movement of the optical fiber 3 or the like, the polarization characteristic of the processing beam and the transmission beam is changed. Since there is no change in the equal state, it is possible to obtain a transmitted laser beam that correctly reflects the intensity of the reflected laser beam. Therefore, it is possible to grasp the intensity of the processing beam and its change state based on the intensity of the transmitted laser light without being influenced by the change in the polarization characteristics of the infrared laser light entering the head unit 2.

  However, in an actually manufactured dichroic mirror, the intensity of light transmitted through the mirror varies due to the difference in the minute structure of the dielectric layer, thereby causing an error in the transmittance. If there is an error between the P-wave transmittance and the S-wave transmittance, the polarization transmittance ratio can be set to 1.0. However, in reality, the transmittance error varies depending on the polarization component. Therefore, it is difficult to make the polarization transmittance ratio completely 1.0. In particular, when the design transmittance of the dichroic mirror is set to a small value, if a relatively large error occurs in the amount of transmitted light of one polarization component, the transmittance of the polarization component varies greatly, and the polarization transmittance ratio also increases. Deviation from 1.0. As a result, an unacceptable difference occurs between the polarization characteristics of the transmitted laser light and the polarization characteristics of the reflected laser light, making it difficult to cope with fluctuations in the polarization characteristics of the infrared laser light from the optical fiber 3.

  As a specific example, let us consider a dichroic mirror in which the transmittance for infrared laser light is set to 1%, but the actual transmitted light amount may cause an error of about 1% of the entire infrared laser light. In this dichroic mirror, if the above-described 1% error occurs only in the transmitted light amount of the P wave, the transmittance of the P wave is 2%. On the other hand, if there is almost no error in the amount of transmitted light of the S wave, the transmittance of the S wave is 1%, so the polarization transmittance ratio to be 1.0 is 2.0.

Here, for example, in the infrared laser light from the optical fiber 3, if the intensity of the S wave does not fluctuate and the intensity of the P wave is greatly reduced, the intensity of the P wave is also greatly increased in the reflected laser light as well. As a result, the overall strength also decreases. On the other hand, the decrease of the P wave in the transmitted laser light is relatively gradual, and the degree of decrease in the overall intensity is also gradual.
Further, in the infrared laser light from the optical fiber 3, when the intensity of the S wave does not vary and the intensity of the P wave slightly increases, the intensity of the P wave of the reflected laser light does not vary greatly. Large changes in strength are unlikely to occur. On the other hand, since the P wave is emphasized in the transmitted laser beam, there is a possibility that the intensity of the P wave is greatly increased and the entire intensity is also increased.

As described above, when the transmittance of the dichroic mirror 22 with respect to the light in the infrared light region is set to be small, an error in the amount of transmitted light greatly affects the transmittance. As a result, the transmitted laser light accurately increases the intensity of the reflected laser light. It will not be expressed. Therefore, in this embodiment, the transmittance of the infrared laser light in the dichroic mirror 22 is set high, so that the polarization transmittance ratio is close to 1.0 and the accuracy of the transmitted laser light is ensured.
For example, assuming that an error corresponding to 1% of the light irradiated to the mirror is generated in the amount of transmitted laser light from the dichroic mirror, if the transmittance is 5%, the polarization transmittance ratio is 0.83 to 0.83. It can be included in the range of 1.2.

  When the transmittance is increased, the reflected laser light incident on the photodiode 23 becomes stronger and the received light amount signal may be saturated. In this embodiment, however, the reflection type attenuator is provided between the dichroic mirror 22 and the photodiode 23. Since the light 24 attenuated by the reflection type attenuator 24 is guided to the photodiode 23, saturation of the photodiode 23 can be prevented. Therefore, by processing the light reception signal from the photodiode 23, the intensity of the processing laser light can be stably obtained.

  Further, when the reflection type attenuator 24 is arranged with its reflection surface orthogonal to the optical path of the transmitted laser light, the infrared laser light reflected by the reflection type attenuator 24 returns to the dichroic mirror 22 and is reflected toward the laser diode 25. However, as a result of the reflected light entering the laser diode 25, the laser diode 25 may be damaged. However, in this embodiment, the reflecting surface of the reflection type attenuator 24 is inclined toward the wall surface on the communication side to the light guide path 201, so that most of the reflected light is guided to the wall surface by the V-shaped groove 204. The diffused light is absorbed by the light absorption film, and the reflected light guided from the reflection type attenuator 24 to the upper wall surface of the light guide path 201 through the dichroic mirror 22 is also absorbed by the light absorption film on the wall surface. Therefore, it is possible to prevent the laser diode 25 from being irradiated with the reflected light.

  In this embodiment, the reflected light from the reflection type attenuator 24 is diffused by the V-shaped groove 204 formed on the wall surface of the light guide path 202. However, the means for diffusing the reflected light is not limited to this. A plurality of protrusions may be provided on the wall, or the wall surface may be roughened by fine irregularities. Moreover, you may give the process which diffuses light to the whole wall surface of the light guide path 202, without limiting a range. However, only a light absorption film made of black alumite or the like may be formed without processing to diffuse light. In addition, a process for diffusing light is applied only to a place where the reflected light from the reflection type attenuator 24 is directly irradiated or a place where there is a possibility of being guided through a dichroic mirror, or a light absorption film is provided. Also good.

  Further, in the above embodiment, the light guide 201 for guiding the visible laser light from the laser diode 25 to the dichroic mirror 22 and the light guide 202 for guiding the infrared laser light transmitted from the dichroic mirror 22 to the photodiode 23. Are communicated in an L-shape via the dichroic mirror 22, but the configuration relating to the communication of the light guide paths 201 and 202 is not limited to this. If the shape of the communicating portion changes, the posture of the reflection type attenuator 24 and the direction of the reflected light from the reflection type attenuator 24 also change. Need to change.

  As specific examples of the above modification, two specific examples will be described below with reference to FIGS. The basic configuration of the optical system of each example is the same as that of the example of FIG. In addition, the same configuration as the example of FIG. 1 and the corresponding configuration are denoted by the same reference numerals. The illustration of the controller 1 is omitted.

2 and 3 show the configuration of the head unit 2 according to the first modification.
In the optical unit 20 of this embodiment, the light guide path 201 including the laser diode 25 and the light guide path 202 including the light receiving element 23 and the reflection type attenuator 24 are set to lengths corresponding to the corresponding optical paths (first embodiment). The light guide paths 201, 202, and 203 are communicated with a light guide path 203 parallel to the mirror surface of the dichroic mirror 22 interposed therebetween.

  The position and orientation of the reflection type attenuator 24 are the same as those in the example of FIG. 1, but the reflection surface is exposed near the communication port to the light guide path 203, so that the reflected light from the reflection type attenuator 24 is reflected. Processing in the light guide 202 is not possible. However, the main reflected light follows a path indicated by a dotted line P in FIG. 2, that is, a path that passes through the light guide path 203 and further crosses the light guide path 201 toward the upper wall surface. Further, as indicated by a dotted line Q in FIG. 3, there is also light reflected from the mirror 22 to the light guide 201 after entering the dichroic mirror 22, but this light is also irradiated on the upper wall surface of the light guide 201. The

  In view of the characteristics of the reflected light, in this embodiment, the light absorption film 210 is formed at least on the upper wall surface of the light guide path 210. Thereby, the infrared laser beam directly guided from the reflection type attenuator 24 to the upper wall surface of the light guide 210 and the infrared laser beam guided from the reflection type attenuator 24 to the wall surface via the dichroic mirror 22. Can be absorbed by the light absorption film 210. Thereby, it is possible to prevent the infrared laser light from entering the laser diode 25.

FIG. 4 shows a configuration of the head unit 2 according to the second modification.
The optical unit 20 of this embodiment is also provided with light guide paths 201, 202, and 203 having the same configuration as that of the first modification, but the reflection type attenuator 24 in the light guide path 202 is the reflection of the previous two examples. The type attenuator 24 is disposed with the mirror surface direction reversed. Due to the inclination of the mirror surface, the infrared laser light transmitted through the dichroic mirror 22 and reflected by the reflection type attenuator 24 enters the dichroic mirror 22 and crosses the light guide path 203 as indicated by a dotted line R in FIG. The light is reflected in the direction, and is irradiated onto the wall surface of the light guide path 203 facing the dichroic mirror 22. Further, since the light absorption film 210 is formed on the wall surface to be irradiated, the infrared laser light guided to the wall surface from the reflection type attenuator 24 via the dichroic mirror 22 is absorbed by the light absorption film 210. Thereby, it is possible to prevent infrared laser light from entering the laser diode 25.

  In both the first and second modifications, the light absorption film 210 may be formed on the entire wall surfaces of the light guide path 201 and the light guide path 203. Further, similarly to the first embodiment, processing for light diffusion by a V-shaped groove or the like may be performed in a range where the light absorption film 210 is formed.

  In both the first embodiment and the two modified examples, the light attenuation filter 24 is not limited to the reflection type, and a filter that absorbs light or a filter that diffuses light can also be used. When these filters are used, the light attenuation filter 24 may be disposed without being inclined. Further, there is no particular problem even if the wall surface of the light guide path is not processed for light absorption or light diffusion.

  In the first and second modifications, the optical unit 20 has three light guide paths 201, 202, and 203 for convenience of explanation, but the light guide path 203 is integrated with the light guide path 201 or the light guide path 202. You may think that

DESCRIPTION OF SYMBOLS 1 Controller 2 Head part 3 Optical fiber 10 Laser light source 22 Dichroic mirror 23 Photodiode 24 Optical attenuation filter (reflection type attenuator)
25 Laser diode 201, 202, 203 Light guide

Claims (8)

Laser light from a laser light source is guided to a head part including a dichroic mirror through an optical fiber, and laser light reflected by the dichroic mirror is emitted to the outside as a processing beam from the head part and transmitted through the dichroic mirror. In the laser processing apparatus provided with a light receiving element for monitoring the intensity of the processing beam in the optical path of the laser beam
The dichroic mirror equalizes the polarization characteristics in the reflected light of the laser light and the polarization characteristics in the transmitted light of the laser light, and transmits the laser light at a ratio exceeding the degree of increase or decrease in the amount of transmitted light corresponding to the error. The light attenuation filter is provided between the dichroic mirror and the light receiving element.
Laser processing equipment. The laser processing apparatus according to claim 1, wherein the dichroic mirror is manufactured according to a design that transmits 5% of the laser light irradiated on the mirror surface. Inside the head portion, a visible light source is provided in which the optical axis is aligned with the optical path of the reflected light from the dichroic mirror with respect to the laser light via the dichroic mirror,
The laser processing apparatus according to claim 1, wherein the dichroic mirror has a characteristic of transmitting a part of a wavelength range of a laser beam emitted from the laser light source and visible light emitted from a visible light source. The light attenuating filter is a reflection type attenuator, and is disposed in a posture in which a reflecting surface is inclined with respect to a direction orthogonal to an optical path of laser light transmitted through the dichroic mirror. The laser processing apparatus according to claim 3, wherein the laser beam that has passed through is reflected in a direction that does not become light traveling toward the visible light source. The head portion includes a first light guide for guiding laser light emitted from the laser light source and transmitted through the dichroic mirror to a light receiving element, and a second light guide for guiding visible light emitted from the visible light source to the dichroic mirror. And both light guides communicate with each other at a place corresponding to the dichroic mirror,
The light attenuating filter is a reflection type attenuator, and is disposed in a posture inclined in the first light guide, and the laser light transmitted from the laser light source through the dichroic mirror to the visible light source due to the inclination. The laser processing apparatus according to claim 3 , wherein the laser beam is reflected in a direction that does not result in light traveling forward. 6. The laser processing apparatus according to claim 5 , wherein the reflection type attenuator is provided with a posture in which laser light transmitted from the laser light source through a dichroic mirror is reflected on a wall surface in the first light guide. 7. 6. The laser processing apparatus according to claim 5 , wherein the reflection type attenuator is provided with a posture to reflect a laser beam transmitted from the laser light source through a dichroic mirror to a wall surface in a second light guide. 7. Wherein the wall surface of the light guide reflected light is guided from the reflection attenuator, processing for absorbing or diffuse reflected light from the reflection-type attenuator is applied, according to any one of claims 5-7 Laser processing equipment.

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