JP2020142276A - Inspection method for laser beam emitting head, laser processing device using it, and laser beam emitting head - Google Patents

Abstract

A laser beam emitting head capable of identifying a surface with a defect without removing a plurality of optical components is provided. and first and second protective glasses 51 and 52 arranged inside the housing 10 and above the light exit 12 with a predetermined gap therebetween. ing. First and second optical function layers 61 and 62 are formed on the top and bottom surfaces of the first protective glass 51, respectively, and third and fourth optical function layers 63 and 64 are formed on the top and bottom surfaces of the second protective glass 52. formed respectively. The first to fourth optical functional layers 61 to 64 have different wavelength dependencies of reflectance. [Selection drawing] Fig. 3

Description

The present invention relates to a laser beam emitting head, a laser processing device using the laser beam emitting head, and a method for inspecting a laser beam emitting head.

Conventionally, there is known a laser processing apparatus that processes a work by emitting a laser beam generated by a laser oscillator toward a work through a laser light emitting head having various optical components inside.

In the laser beam emitting head, a protective glass is provided in the vicinity of the laser beam emitting port in order to protect the optical components arranged inside from fume, sputtering, etc. generated during laser processing. Further, during laser processing, in order to prevent oxidation of the processed portion, processing is performed while spraying a shield gas on the work, and the shield gas suppresses adhesion of fume or the like to the protective glass.

However, the surface of the protective glass becomes more dirty as the number of workpieces to be processed and the processing time elapses, causing a decrease in the transmittance of the laser beam. This decrease in transmittance may cause a decrease in the output of the laser beam irradiating the work, or in an extreme case, the laser beam may be reflected inside the laser beam emitting head by the protective glass and damage the above optical components. There is.

Therefore, it has been proposed that a glass holder is detachably provided on the laser beam emitting head, and a protective glass is attached to the holder so that the protective glass can be easily replaced (see, for example, Patent Documents 1 and 2).

Further, a configuration has been proposed in which the surface of the protective glass is irradiated with the detection light from a direction inclined with respect to the optical axis of the laser light, and the reflected light is detected to evaluate the degree of defects adhering to the surface of the protective glass. (See, for example, Patent Document 2).

In addition, a reflection mechanism that reflects visible light from the work is provided inside the laser beam emitting head, and the visible light is captured by the camera with this reflection mechanism to inspect the welded state of the work and the surface condition of the protective glass. A configuration has been proposed (see, for example, Patent Document 3).

International Publication No. 2018/139019 Japanese Patent No. 5997965 Japanese Patent No. 6049391

By the way, in order to surely prevent fume and the like from adhering to the inside of the laser beam emitting head, a plurality of protective glasses are usually arranged at predetermined intervals in the optical axis direction of the laser beam.

However, in this case, it is difficult to determine whether or not a defect is attached to any surface of the plurality of protective glasses. For this reason, a method such as periodically replacing a plurality of protective glasses at once has been adopted.

However, in such a method, the protective glass must be replaced frequently, and unnecessary maintenance work such as replacement and cleaning of the protective glass in a normal state occurs. Further, it is difficult to determine whether or not a defect is attached to any surface of a plurality of optical components arranged inside the laser beam emitting head, not limited to the protective glass.

The present invention has been made in view of this point, and an object of the present invention is a laser beam emitting head capable of identifying a surface to which a defect is attached without removing an optical component disposed inside, and laser processing using the laser beam emitting head. An object of the present invention is to provide an inspection method for an apparatus and a laser beam emitting head.

In order to achieve the above object, the laser light emitting head according to the present invention is a laser light emitting head that emits laser light, and the light incident port on which the laser light is incident and the laser on the lower side. A plurality of optical components each having a light emitting port from which light is emitted and a plurality of optical components inside the housing and above the light emitting port at predetermined intervals and having an upper surface and a lower surface, respectively. And, among the different surfaces of the plurality of optical components, at least two surfaces are formed with optical functional layers having a reflectance of wavelength dependence, and are formed on the plurality of optical components. The optical functional layer is characterized in that the wavelength dependence of the reflectance is different from each other.

According to this configuration, it is possible to identify the surface to which the defect is attached without removing the optical component from the housing. In addition, it is possible to suppress an increase in unnecessary maintenance work.

The laser processing apparatus according to the present invention holds the laser apparatus for generating a laser beam, the laser beam emitting head that receives the laser beam and irradiates the work, and the laser beam emitting head at a desired position. It is characterized by having at least a manipulator to move.

According to this configuration, it is possible to suppress an increase in downtime of the laser processing apparatus. In addition, it is possible to quickly detect an abnormality or decrease in the output of the laser beam emitted from the laser beam emitting head, and it is possible to suppress the occurrence of processing defects.

The method for inspecting a laser beam emitting head according to the present invention includes a first measurement light incident step of incidenting first measurement light of a first wavelength from the light emission port toward the plurality of optical components, and the optical functional layer. First, the first measurement light reflected on any surface on which the first measurement light is formed is received, and the presence or absence of defects on the surface of the optical component to which the first measurement light is reflected is evaluated based on the light reception result. It is characterized by having at least an evaluation step.

According to this method, images of reflected light on a specific surface of a plurality of optical components can be obtained according to the wavelength of the incident light, and based on this, the presence or absence of defects on the surface can be determined. Can be evaluated.

According to the laser beam emitting head of the present invention, it is possible to identify the surface to which the defect is attached without removing the optical component disposed inside. According to the laser processing apparatus of the present invention, it is possible to suppress an increase in downtime. In addition, it is possible to suppress the occurrence of processing defects. it can. According to the method for inspecting the laser beam emitting head according to the present invention, it is possible to evaluate the presence or absence of defects on a specific surface in the optical components arranged inside.

It is a schematic diagram which shows the structure of the laser processing apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows the structure of the laser beam emitting head. It is a figure which shows an example of the wavelength dependence of the reflectance of the 1st to 4th optical functional layers. It is a figure which shows an example of the laminated structure of the 1st and 2nd optical functional layers. It is a figure which shows the wavelength dependence of the reflectance of the 1st and 2nd optical functional layers shown in FIG. It is a schematic diagram explaining the inspection procedure of the 1st protective glass.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of preferred embodiments is merely exemplary and is not intended to limit the present invention, its applications or its uses.

(Embodiment)
[Construction of laser processing equipment]
FIG. 1 shows a configuration of a laser processing apparatus according to the present embodiment. The laser processing apparatus 1000 includes a laser apparatus 100, a laser beam emitting head 200, an optical fiber 300, a manipulator 400, and a control unit 500.

The laser light generated by the laser device 100 is guided to the laser light emitting head 200 via the optical fiber 300. The laser beam emitting head 200 irradiates the work W with the laser beam guided by the optical fiber 300. A laser processing head 200 is attached to the tip of the manipulator 400, and the laser processing head 200 is moved. The control unit 500 controls the operation of the manipulator 400 and the laser oscillation in the laser device 100. The laser device 100 is supplied with electric power for laser oscillation from a power source (not shown), and the control unit 500 is connected to the power source.

The laser processing apparatus 1000 operates a manipulator 400 to which the laser beam emitting head 200 is attached, and irradiates the laser beam output from the laser apparatus 100 toward the work W in a desired trajectory to cut the work W. It is used for welding, drilling, etc. In this embodiment, the wavelength of the laser beam is about 900 nm to 1 μm.

[Internal configuration of laser beam emitting head]
FIG. 2 shows a schematic cross-sectional view of the laser beam emitting head according to the present embodiment. Although the actual laser beam emitting head 200 is provided with components other than those shown in FIG. 2, the illustration and description thereof will be omitted for convenience of explanation.

The laser beam emitting head 200 includes a housing 10, a connector 20, a collimating lens 30, a condensing lens 40, a first protective glass 51, a second protective glass 52, and a glass holder 70.

In the following description, the side on which the optical fiber 300 is attached to the housing 10 may be referred to as an upper or upper side, and the opposite side may be referred to as a lower or lower side along the optical path direction of the laser beam.

Further, components that transmit laser light, such as the first and second protective glasses 51 and 52, the collimating lens 30, and the condensing lens 40, may be referred to as "optical components". The laser beam emitting head 200 may be provided with optical components other than those shown in FIG.

The housing 10 has a light incident port 11 on the upper side and a light emitting port 12 on the lower side, and a connector 20 is attached to the light incident port 11. Further, one end of the optical fiber 300 is attached to the connector 20, and the laser beam propagating through the optical fiber 300 is guided to the inside of the housing 10 through the light incident port 11.

The collimating lens 30 is arranged inside the housing 10 and converts the laser beam into parallel light. The condensing lens 40 is arranged under the collimating lens 30 at a predetermined interval, and the parallel light transmitted through the collimating lens 30 is reduced to a predetermined magnification and condensed.

The first and second protective glasses 51 and 52 are arranged inside the housing 10 and above the light emitting port 12. The first protective glass 51 is arranged on the lower side of the condensing lens 40 at a predetermined interval, and the second protective glass 52 is further arranged on the lower side thereof. The first and second protective glasses 51 and 52 prevent fume and the like from the work W from entering the inside of the housing 10 during laser processing, respectively. In particular, if a fume or the like adheres to the condensing lens 40 or the collimating lens 30, not only the output of the laser beam is reduced, but also the laser beam may deviate from the desired optical path, and such a problem is prevented. The first and second protective glasses 51 and 52 are made of high-purity quartz glass.

The glass holder 70 forms a part of the housing 10 and holds the first and second protective glasses 51 and 52. Further, the glass holder 70 is provided detachably from the housing 10.

The laser beam guided to the inside of the housing 10 passes through the collimating lens 30 and the condensing lens 40, respectively, and further passes through the first and second protective glasses 51 and 52 while undergoing predetermined conversion. It is emitted to the outside from the exit port 12. In the example shown in FIG. 1, the work W is irradiated.

Further, the first and second optical functional layers 61 and 62 are formed on the upper surface and the lower surface of the first protective glass 51, respectively. The third and fourth optical functional layers 63 and 64 are formed on the upper surface and the lower surface of the second protective glass 52, respectively.

The first to fourth optical functional layers 61 to 64 are dielectric films having different dielectric constants, in this case, a dielectric multilayer film in which dio ₂ films and SiO ₂ films are alternately laminated (see FIG. 4). ).

FIG. 3 shows the wavelength dependence of the reflectance of the first to fourth optical functional layers, and as is clear from FIG. 3, the reflectance of each of the first to fourth optical functional layers has a wavelength dependence. And the wavelength dependence of the reflectance is different from each other. Specifically, each laminated structure is adjusted so that the peaks having the maximum reflectance do not overlap each other. For example, the film thickness and the number of layers of the TiO ₂ film and the SiO ₂ film are adjusted. In the example shown in FIG. 3, the first optical functional layer 61 has a maximum reflectance at a wavelength of around 400 nm, and the second optical functional layer 62 has a maximum reflectance at a wavelength of around 450 nm. Further, the third optical functional layer 63 has a maximum reflectance when the wavelength is around 500 nm, and the fourth optical functional layer 64 has a maximum reflectance when the wavelength is around 550 nm. Note that FIG. 3 shows only an example, and the maximum value of the reflectance and the wavelength when the reflectance is maximum can be appropriately changed according to the inspection specifications of the protective glass described later.

The laminated structure of the first to fourth optical functional layers 61 to 64 is adjusted so that the reflectance is less than 1% at the wavelength of the laser beam. Further, the laminated structure of each of the first to fourth optical functional layers 61 to 64 is adjusted so that the absorption rate of the laser beam is less than 1%. By doing so, the first and second protective glasses 51 and 52 on which the first to fourth optical functional layers 61 to 64 are formed are designed so that the laser beam is not substantially reflected or absorbed. ing.

FIG. 4 shows an example of the laminated structure of the first and second optical functional layers, and FIG. 5 shows the wavelength dependence of the reflectance of the first and second optical functional layers shown in FIG.

In the configuration shown in FIG. 4, the first and second optical functional layers 61 and 62 are dielectric multilayer films having a five-layer structure in which dio ₂ films and SiO ₂ films are alternately laminated, and the thickness of each layer is high. The wavelength dependence of the reflectance is adjusted by making them different. Further, the first layer located on the first protective glass 51 side and the fifth layer located on the atmosphere side are both TiO ₂ films.

As is clear from FIG. 5, when the wavelength of the incident light incident on the first protective glass 51 is about 480 nm, 70% or more of the incident light is reflected by the first optical functional layer 61, while the second The reflectance of the optical functional layer 62 is less than 5%, and most of the incident light passes through the second optical functional layer 62. Further, when the wavelength of the incident light is about 630 nm, 50% or more is reflected by the second optical functional layer 62, while the reflectance of the first optical functional layer 61 is less than 5%, and most of the incident light. Transmits through the first optical functional layer 61.

Utilizing such a difference in optical characteristics, it is possible to optically inspect the surfaces of the first and second protective glasses 51 and 52 on which the first to fourth optical functional layers 61 to 64 are formed, respectively. Become. This will be described later.

Although not particularly described, the desired reflection characteristics can be realized in the third and fourth optical functional layers 63 and 64 by similarly changing the film thickness and the number of layers of the TiO ₂ film and the SiO ₂ film. The types of dielectric films constituting the first to fourth optical functional layers 61 to 64 and the number of layers of each layer can be appropriately changed according to the required performance.

[Protective glass inspection procedure]
FIG. 6 shows a schematic diagram illustrating an inspection procedure of the first protective glass, FIG. 6A shows an inspection procedure using the first measurement light having a wavelength of 400 nm, and FIG. 6B shows an inspection procedure using a wavelength of 450 nm. The inspection procedure using the second measurement light is shown respectively. For convenience of explanation, the same parts as those in FIG. 2 are designated by the same reference numerals and detailed description thereof will be omitted. The reflectances of the first and second optical functional layers 61 and 62 formed on the first protective glass in FIG. 6 have the wavelength dependence shown in FIG.

As shown in FIG. 6A, the first measurement light having a wavelength of 400 nm is emitted from the light emission port 12 side from the first measurement light source 81 toward the first and second protective glasses 51 and 52. The reflected light is imaged by the camera 90. At this wavelength, the reflectance of the first optical functional layer 61 is higher than that of the second to fourth optical functional layers 62 to 64. Therefore, in the camera 90, the first optical functional layer 61, that is, the upper surface of the first protective glass 51. The reflected image at is captured. Therefore, if a defect such as a fume is attached to the first optical functional layer 61, the incident light is scattered in that portion, and the brightness of the image is lowered. That is, that part becomes dark. If a defect is attached to the lower surface of the first protective glass 51, that is, the second optical functional layer 62, the incident light is scattered even in this portion, and a dark portion is generated on the image. Similarly, if a defect is attached to the upper surface and / or the lower surface of the second protective glass 52, the image of the corresponding portion on the image becomes dark.

Next, as shown in FIG. (B), the second measurement light having a wavelength of 450 nm is emitted from the second measurement light source 82 toward the first protective glass 51, and the reflected light is imaged by the camera 90. At this wavelength, the reflectance of the second optical functional layer 62 is higher than that of the first, third, and fourth optical functional layers 61, 63, 64. Therefore, in the camera 90, the second optical functional layer 62, that is, the first A reflected image on the lower surface of the protective glass 51 is captured. Therefore, if a defect such as a fume is attached to the second optical functional layer 62, the incident light is scattered in that portion and the portion becomes dark. Further, as shown in FIG. (A), if defects are attached to the upper surface of the first protective glass 51 and the upper surface and / or the lower surface of the second protective glass 52, the image of the corresponding portion on the image is displayed. Get dark.

In this way, the wavelengths of the measurement light incident on the first and second protective glasses 51 and 52 are set to the first and fourth optical functional layers formed on the upper and lower surfaces of the first and second protective glasses 51 and 52, respectively. By changing the reflectance according to the reflectance of 61 to 64, a reflected image on each surface can be obtained.

For example, in the first and second protective glasses 51 and 52 arranged as shown in FIG. 2, the first and fourth measurement lights having wavelengths of 400 nm, 450 nm, 500 nm and 550 are sequentially emitted from the light emission port 12 side. 2 The light is emitted toward the protective glasses 51 and 52, and the reflected light is imaged by the camera 90, respectively.

When the fourth measurement light having a wavelength of 550 nm is incident, the fourth measurement light is partially reflected by the fourth optical functional layer 64, but the fourth measurement light is reflected by the first to third optical functional layers 61 to 63. Not done. Therefore, the presence or absence of defects on the lower surface of the second protective glass 52, and the positions and densities of the defects can be estimated based on the image acquired by incident the fourth measurement light.

Further, by comparing and analyzing the image acquired by incidenting the third measurement light having a wavelength of 500 nm and the image acquired by incidenting the fourth measurement light, defects on the upper surface of the second protective glass 52 are found. The presence or absence, and the position and density of defects can be estimated.

Similarly, by comparing and analyzing the image acquired by incidenting the above-mentioned second measurement light and the image acquired by incidenting the third measurement light, the presence or absence of defects on the lower surface of the first protective glass 51 , And the location and density of defects can be estimated. By comparing and analyzing the image acquired by incidenting the first measurement light and the image acquired by incidenting the second measurement light, the presence or absence of defects on the upper surface of the first protective glass 51 and defects are obtained. The position and density of the light can be estimated. Needless to say, this inspection procedure and method can be applied even when three or more protective glasses are arranged inside the laser beam emitting head 200.

[Effects, etc.]
As described above, the laser beam emitting head 200 according to the present embodiment has a housing having a light incident port 11 on which the laser beam is incident on the upper side and a light emitting port 12 on which the laser beam is emitted on the lower side. 10 and first and second protective glasses (optical components) 51 and 52 arranged inside the housing 10 above the light emitting port 12 at predetermined intervals are provided at least.

The first to fourth optical functional layers 61 to 64 having a reflectance of wavelength dependence are formed on the upper surface and the lower surface of the first and second protective glasses 51 and 52, respectively. The first and fourth optical functional layers 61 to 64 formed on different surfaces of the first and second protective glasses 51 and 52 have different wavelength dependences of reflectance.

By configuring the laser beam emitting heads, particularly the first and second protective glasses 51 and 52 in this way, the upper surfaces and the upper surfaces of the first and second protective glasses 51 and 52, respectively, are configured according to the wavelength of the incident light. Images of the reflected light on the lower surface can be acquired individually. As a result, the surface to which the defect is attached can be identified without removing the first and second protective glasses 51 and 52 from the housing 10. In addition, the laser beam emitting head 200 can be reliably maintained without increasing the maintenance frequency.

The first to fourth optical functional layers 61 to 64 formed on different surfaces of the first and second protective glasses 51 and 52 are configured so that the peaks having the maximum reflectance do not overlap each other. preferable.

By doing so, the light reflected on the image of the reflected light on one of the upper and lower surfaces of the first and second protective glasses 51 and 52, except for the defective portion, is reflected on the other surface. It is possible to reduce the amount of glass entering, and it is possible to reliably determine the presence or absence of defects on each surface.

The first to fourth optical functional layers 61 to 64 may be a dielectric multilayer film in which dielectric films having different dielectric constants are alternately laminated. By doing so, it becomes easy to adjust the wavelength dependence of the reflectance in each layer.

It is preferable that the reflectance of the laser beam of each of the first to fourth optical functional layers 61 to 64 is a predetermined value or less. By doing so, it is possible to eliminate the loss of the laser beam inside the laser beam emitting head 200. Further, the N / S ratio in the reflected image on each surface can be improved, and the accuracy of determining the presence or absence of defects can be improved. It is more preferable that the first to fourth optical functional layers 61 to 64 are designed so that the laser beam is not substantially reflected or absorbed.

The wavelength at which the reflectances of the first to fourth optical functional layers 61 to 64 formed on the first and second protective glasses 51 and 52 are maximized monotonously changes as the distance from the light emitting port 12 increases. Is preferable. By doing so, the images of the reflected light reflected on the upper and lower surfaces of the first and second protective glasses 51 and 52 are sequentially compared and analyzed to determine the presence or absence of defects on each surface. It can be determined with certainty. In addition, the determination process is simplified. In the example shown in FIG. 3, the wavelength at which the reflectance of the first to fourth optical functional layers 61 to 64 is maximized monotonically increased as the distance from the light emitting port 12 increased, but decreased monotonically. You may be doing it. Further, even if the wavelength at which the reflectances of the first to fourth optical functional layers 61 to 64 are maximized does not change monotonically, the first and second protective glasses can be appropriately selected by appropriately selecting the images to be compared. It is possible to determine the presence or absence of defects on the upper and lower surfaces of 51 and 52, respectively.

Further, the laser processing device 1000 according to the present embodiment holds a laser device 100 that generates a laser beam, a laser beam emitting head 200 that receives the laser beam and irradiates the work W, and a laser beam emitting head 200. It also includes at least a manipulator 400 that moves it to a desired position.

According to the present embodiment, since the surface to which the defect is attached can be identified without removing the first and second protective glasses 51 and 52 from the housing 10, maintenance of the laser beam emitting head 200 and eventually the laser processing apparatus 1000 is maintained. The frequency can be appropriate. As a result, it is possible to suppress an increase in the downtime of the laser processing apparatus 1000. In addition, since it is possible to easily inspect the presence or absence of defects attached to the first and second protective glasses 51 and 52, it is possible to quickly detect an abnormality or decrease in the output of the laser beam emitted from the laser beam emitting head 200, resulting in processing defects. It can be suppressed from occurring.

In the inspection method of the laser beam emitting head 200 according to the present embodiment, the first measurement light incident in which the first measurement light of the first wavelength is incident from the light emission port 12 toward the first and second protective glasses 51 and 52. The step and the first measurement light reflected on any of the surfaces of the first and second protective glasses 51 and 52 are received, and based on the light reception result, the presence or absence of defects on the surface on which the first measurement light is reflected is determined. It includes at least a first evaluation step to evaluate.

According to the present embodiment, since the wavelength dependence of the reflectance in the first to fourth optical functional layers 61 to 64 is different from each other, the image of the reflected light on a specific surface is imaged according to the wavelength of the incident light. Can be obtained, and based on this, the presence or absence of defects in the relevant surface can be evaluated.

After the first evaluation step, a second measurement light incident step in which a second measurement light different from the first wavelength is incident from the light outlet 12 toward the first and second protective glasses 51 and 52, and a plurality of protective glasses. The second evaluation step of receiving the second measurement light reflected on any of the surfaces in the above and evaluating the presence or absence of defects on the surface on which the second measurement light is reflected is further provided based on the light reception result. Is preferable.

By doing so, for example, even when the information of the defect attached to the other surface is superimposed on the image of the reflected light on one surface, the influence is removed and the image of the one surface is covered. The presence or absence of attached defects can be correctly determined.

Further, in the first and second evaluation steps, it is preferable to evaluate the position and distribution of defects on any surface of the first and second protective glasses 51 and 52. By doing so, for example, it is possible to determine whether or not the protective glass should be replaced, or whether or not it can be handled only by surface cleaning, and the maintenance efficiency of the laser beam emitting head 200 can be improved.

(Other embodiments)
In order to improve the sensitivity of the image captured by the camera 90, it is preferable to provide a bandpass filter (not shown) in front of the light receiving surface of the camera 90 to acquire an image corresponding to the wavelength of each measurement light. Further, in the example shown in FIG. 6, an example in which the first measurement light source 81 and the second measurement light source 82 are used properly according to the wavelength is shown, but the present invention is not particularly limited to this. For example, a white light source and a bandpass filter may be used to adjust the wavelength of the measurement light. Further, the bandpass filter applied to the camera 90 and the bandpass filter applied to the measurement light source may have a configuration in which a plurality of filters for a specific wavelength are arranged, or may be a variable filter. Further, the measurement light source may be a laser or an LED. Further, an optical interferometer may be used instead of the camera 90.

Although FIG. 2 shows an example in which the first and second protective glasses 51 and 52 are housed in the same glass holder 70, the first protective glass 51 and the second protective glass 52 are different glass holders. It may be accommodated in. By doing so, the protective glass whose surface is dirty exceeds the permissible value can be replaced individually and easily.

Further, it is preferable that the protective glass located on the side closest to the light emitting port 12, in other words, the side closest to the work W, and the other protective glasses are housed in different glass holders. Since defects are most likely to adhere to the former protective glass, by making the protective glass on the side closest to the work W replaceable with the other protective glass separately, unnecessary replacement work and maintenance work will occur. Can be suppressed.

Further, although FIG. 2 shows an example in which two protective glasses 51 and 52 are used, three or more protective glasses may be arranged inside the housing 10. Further, only one protective glass may be used. In these cases as well, it goes without saying that optical functional layers having different wavelength dependences of reflectance are provided on different surfaces of the protective glass.

Further, optical components other than the protective glass, for example, the upper surface and the lower surface of the collimating lens 30 and the condensing lens 40 may be provided with optical functional layers having different wavelength dependences of reflectance.

Further, it is not necessary that all the upper surfaces and lower surfaces of the first and second protective glasses 51 and 52 are provided with optical functional layers having different wavelength dependences of reflectance. For example, optical functional layers having different wavelength dependences of reflectance may be provided only on the lower surfaces of the first and second protective glasses 51 and 52, respectively. Similarly, in optical components other than the first and second protective glasses 51 and 52 and provided with the optical functional layer, the optical functional layer having different wavelength dependence of reflectance on all surfaces is also used. May not be provided. For example, if a surface on which fume or the like is likely to adhere can be specified in advance, the above-mentioned optical functional layer may be provided on that surface.

That is, the laser beam emitting head 200 disclosed in the present specification has the following configuration. The laser beam emitting head 200 includes a housing 10 having a light incident port 11 on which laser light is incident on the upper side and a light emitting port 12 on which laser light is emitted on the lower side, and inside the housing 10. A plurality of optical components arranged above the light emitting port 12 at predetermined intervals and having an upper surface and a lower surface, respectively, are provided.

Of the surfaces different from each other in the plurality of optical components, at least two surfaces are formed with an optical functional layer having a reflectance wavelength dependence, and the reflectance wavelength dependence is different from each other.

The optical functional layers formed on the plurality of optical components are configured so that the peaks having the maximum reflectance do not overlap each other.

The reflectance of the laser beam of each of the optical functional layers formed on the plurality of optical components is equal to or less than a predetermined value.

The wavelength at which the reflectance of the optical functional layers formed on the plurality of optical components is maximized changes monotonically as the distance from the light emission port 12 increases.

The laser beam emitting head of the present invention can identify the surface to which defects are attached without removing optical components such as protective glass, and is therefore useful for application to a laser processing apparatus that processes with high-power laser light. ..

10 Housing 11 Light inlet 12 Light outlet 20 Connector 30 Collimating lens 40 Condensing lens 51 First protective glass 52 Second protective glass 61-64 First to fourth optical functional layers 70 Glass holder 81 First measurement light source 82 Second measurement light source 90 Camera 100 Laser device 200 Laser light emission head 300 Optical fiber 400 Manipulator 500 Control unit 1000 Laser processing device

Claims (9)

A laser beam emitting head that emits laser light.
A housing having a light incident port on the upper side where the laser beam is incident and a light emission port on the lower side where the laser beam is emitted.
A plurality of optical components, which are arranged inside the housing and above the light emitting port at predetermined intervals and have an upper surface and a lower surface, respectively, are provided at least.
Of the surfaces different from each other in the plurality of optical components, at least two surfaces are formed with an optical functional layer having a reflectance wavelength dependence.
The optical functional layer formed on the plurality of optical components is a laser beam emitting head characterized in that the wavelength dependence of the reflectance is different from each other. In the laser beam emitting head according to claim 1,
A laser beam emitting head characterized in that the optical functional layer formed on the plurality of optical components is configured so that peaks having maximum reflectance do not overlap each other. In the laser beam emitting head according to claim 1 or 2.
The optical functional layer is a laser beam emitting head characterized by being a dielectric multilayer film formed by alternately laminating dielectric films having different dielectric constants. The laser beam emitting head according to any one of claims 1 to 3.
Each of the optical functional layers formed on the plurality of optical components is a laser beam emitting head characterized in that the reflectance of the laser beam is equal to or less than a predetermined value. In the laser beam emitting head according to any one of claims 1 to 4.
A laser beam emitting head characterized in that the wavelength at which the reflectance of the optical functional layer formed on the plurality of optical components becomes maximum changes monotonically as the distance from the light emitting port increases upward. A laser device that generates laser light and
The laser beam emitting head according to any one of claims 1 to 5, which receives the laser beam and irradiates the work with the laser beam.
A laser processing apparatus including at least a manipulator that holds the laser beam emitting head and moves it to a desired position. The method for inspecting a laser beam emitting head according to any one of claims 1 to 5.
A first measurement light incident step in which a first measurement light having a first wavelength is incident on the plurality of optical components from the light outlet,
The first measurement light reflected on any surface on which the optical functional layer is formed is received, and based on the light reception result, the presence or absence of defects on the surface of the optical component to which the first measurement light is reflected is determined. A method for inspecting a laser beam emitting head, which comprises at least a first evaluation step for evaluation. In the method for inspecting a laser beam emitting head according to claim 7.
After the first evaluation step, a second measurement light incident step in which a second measurement light different from the first wavelength is incident on the plurality of protective glasses from the light outlet, and a second measurement light incident step.
The second measurement light reflected on any surface on which the optical functional layer is formed is received, and based on the light reception result, the presence or absence of defects on the surface of the optical component to which the second measurement light is reflected is determined. A method for inspecting a laser beam emitting head, which further comprises a second evaluation step for evaluation. In the method for inspecting a laser beam emitting head according to claim 8,
A method for inspecting a laser beam emitting head, which comprises evaluating the position and distribution of the defect on the surface of the optical component in the first evaluation step and the second evaluation step.

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