TWI878800B - Optical components and laser processing machines - Google Patents

Abstract

The optical component (10) comprises a substrate (1) and a multilayer film (7). The multilayer film (7) is laminated on the substrate (1). The multilayer film (7) is composed of at least three layers of a fluoride film (4), a yttrium (III) fluoride film, a germanium (Ge) film (5) and a diamond-like carbon (DLC) film (6) laminated in sequence from the substrate (1). The optical component (10) is configured not to use oxides, and infrared light can penetrate at a high transmittance.

Description

Optical components and laser processing machines

This disclosure relates to an optical component and a laser processing machine having the optical component.

A laser processing machine that processes a workpiece by irradiation with laser light is provided with a protective window, which is an optical component for protecting a lens system including a focusing lens. The protective window protects the lens system from dust or splashes generated during processing. In the case of a laser processing machine that uses a carbon dioxide (CO ₂ ) laser as a laser light source, the protective window is required to have a high transmittance of infrared CO ₂ irradiation light. In addition, the protective window needs to have environmental resistance such as wear resistance and corrosion resistance. The wear resistance is to suppress scratches when wiping off foreign matter attached to the protective window, and the corrosion resistance is to prevent corrosion from occurring due to the surrounding of the protective window during laser processing.

Patent document 1 discloses an infrared-transmitting structure, which is an optical component having a substrate made of zinc sulfide (ZnS), and a first yttrium oxide ( _Y2O3 ) film, a _yttrium (III) fluoride ( _YF3 ) film, a second _Y2O3 film, a germanium (Ge) film, and _a diamond-like carbon (DLC) film sequentially stacked from the substrate surface. The optical component of Patent document 1 has high environmental resistance by providing a DLC film on the surface of the optical component. That is, the optical component of Patent document 1 has high environmental resistance by forming a multi-layer film on the surface of the ZnS substrate, with the DLC film having excellent environmental resistance as the outermost layer. In the optical component of Patent Document 1, a YF ₃ film is sandwiched between a first Y ₂ O ₃ film and a second Y ₂ O ₃ film, thereby ensuring the close contact between the substrate, the YF ₃ film and the DLC film.

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 2008-268277

However, in the optical component of the above-mentioned patent document 1, the DLC film provided on the outermost layer of the multilayer film has a compressive stress, so that a force is applied to the entire multilayer film, and there is a risk of film peeling at the interface with low adhesion in the multilayer film. Therefore, in the optical component of patent document 1, a Ge layer is formed as a close contact layer of the DLC film, and _a two-layer oxide _Y2O3 layer is formed as a close contact layer of the _YF3 layer to ensure the close contact of the _multilayer film. On the other hand, the oxide film such as the _Y2O3 film has a high absorption rate of infrared light, which becomes a factor that reduces the transmittance of infrared light in the optical component. Therefore, in the optical component of patent document 1, a high transmittance of infrared light cannot be obtained.

When laser processing is performed by a laser processing machine that uses an optical component with low infrared light transmittance as a protective window as in Patent Document 1, the optical component absorbs infrared light and a temperature distribution occurs on the substrate of the optical component, resulting in a decrease in the transmission accuracy of the laser light due to the thermal lens effect. Then, the decrease in the transmission accuracy of the laser light in the laser processing machine is related to the decrease in processing accuracy.

This disclosure is made in view of the above, and aims to obtain an optical component that can transmit infrared rays with high transmittance.

In order to solve the above problems and achieve the purpose, the optical component disclosed in the present invention has: a substrate composed of zinc selenide; and a multi-layer film composed of at least three layers, in which a fluoride film, a germanium film and a diamond-like carbon film are sequentially stacked from the substrate side.

According to the optical components disclosed herein, infrared light can be penetrated with high transmittance.

1: Substrate

2: First side

2a: Non-film forming area

3: Second side

4: Fluoride membrane

5:Ge film

6:DLC film

7,71,72: Multi-layer membrane

8: Anti-reflective film

10,11,12: Optical components

20,30,30a,30b: Laser processing machine

21: Laser oscillator

22: Laser light

23: Focusing lens

24: Protective window

25: Object to be processed

31: Lens barrel

32: Covering

41:Film forming jig

41a: Holding part

50: Cooling air device

51: Air supply department

52: Air supply and communication department

53: Air supply memory unit

54: Air supply control unit

60: Control device

61: Control device communication unit

62: Control device memory unit

63: Control device control unit

81: Processor

82:Memory

631: Laser control unit

632: Cooling air control unit

Figure 1 is a cross-sectional view showing the structure of the optical components related to implementation form 1.

Figure 2 is a cross-sectional view showing other components of the optical component related to implementation form 1.

Figure 3 is a diagram showing an example of the wavelength dependence of transmittance in an optical component related to implementation form 1.

Figure 4 is a graph showing the wavelength dependence of transmittance in an optical component of a comparative example of implementation form 1.

Figure 5 is a diagram showing the schematic structure of a laser processing machine related to implementation form 2.

Figure 6 is a cross-sectional view showing the structure of the optical components related to implementation form 3.

Figure 7 is a diagram showing the schematic structure of a laser processing machine related to implementation form 3.

Figure 8 is a cross-sectional view showing the details of the installation environment of the protective window in the laser processing machine related to the implementation form 3.

Figure 9 is a cross-sectional view of a substrate and a jig viewed from the side when forming a multi-layer film on a substrate using the PVD method in Embodiment 3.

Figure 10 is a top view of the fixture related to implementation form 3.

Figure 11 is a first diagram illustrating the film forming step of a multi-layer film on a substrate according to the PVD method in Embodiment 3.

Figure 12 is a second diagram illustrating the film forming step of forming a multi-layer film on a substrate by the PVD method in Embodiment 3.

Figure 13 is a third diagram illustrating the film forming step of forming a multi-layer film on a substrate by the PVD method in Embodiment 3.

Figure 14 is a diagram showing the schematic structure of a laser processing machine related to implementation form 4.

Figure 15 is a block diagram showing the functional structure of the laser processing machine related to implementation form 4.

Figure 16 is a diagram showing the schematic structure of another laser processing machine related to implementation form 4.

Figure 17 is a block diagram showing the functional structure of the control device of other laser processing machines related to implementation form 4.

Figure 18 is a diagram showing an example of the hardware configuration of the processing circuit related to implementation form 4.

[Form used to implement the invention]

Below, the optical components and laser processing machines related to the implementation form are described in detail based on the diagrams.

Implementation form 1

FIG. 1 is a cross-sectional view showing the structure of an optical component related to implementation form 1. The optical component 10 shown in FIG. 1 comprises: a substrate 1 composed of zinc selenide (ZnSe); a multilayer film 71, which is a multilayer film 7 disposed on a first surface 2 of the main surface of the substrate 1; and a multilayer film 72, which is a multilayer film 7 disposed on a second surface 3 of the substrate 1, the second surface 3 being a surface facing the opposite side to the side facing the first surface 2.

The substrate 1 is a substrate made of ZnSe, which is a material with relatively high infrared light transmittance among optical materials. Thus, the infrared light transmittance in the substrate 1 and the optical component 10 can be improved compared with the case where the optical component 10 is made of an optical material with lower infrared light transmittance than ZnSe.

The shape of the substrate 1 can be set to any shape. When the optical component 10 is used as a protective window of a laser processing machine, from the perspective of the processing area of the laser processing machine, the shape of the substrate 1 is a circular plate with a diameter of 80 mm to 140 mm. In addition, from the perspective of film stress, the thickness of the substrate 1 is 2 mm to 10 mm.

The substrate 1 in the embodiment 1 has a disk shape in which the outer shape of the first surface 2 and the outer shape of the second surface 3 are set to be circular. In the substrate 1, the in-plane direction of the first surface 2 is parallel to the in-plane direction of the second surface 3. In the substrate 1, the central axis of the circle of the first surface 2 and the central axis of the circle of the second surface 3 are set to be coaxial. The main surface is set to be the surface of the substrate 1 on the side where light incident on the substrate 1 emerges.

The multilayer film 7 has three film layers, namely, a fluoride film 4, a Ge film 5, and a DLC film 6. In the first embodiment, the case where a YF ₃ film is used as the fluoride film 4 is described. As shown in FIG. 1 , a multilayer film 71 of the multilayer film 7 is provided on the first surface 2 of the substrate 1. Also, a multilayer film 72 of the multilayer film 7 is provided on the second surface 3 of the substrate 1.

The multilayer film 71 disposed on the first surface 2 is composed of three layers stacked in the order of a fluoride film 4, a Ge film 5, and a DLC film 6 from the first surface 2 side. The DLC film 6 forms the outer surface of the optical component 10 on the side of the substrate 1 facing the first surface 2. The Ge film 5 is disposed between the fluoride film 4 and the DLC film 6.

The multilayer film 72 disposed on the second surface 3 is composed of three layers stacked in the order of the fluoride film 4, the Ge film 5 and the DLC film 6 from the second surface 3. The DLC film 6 forms the outer surface of the optical component 10 on the side of the substrate 1 facing the second surface 3. The Ge film 5 is disposed between the fluoride film 4 and the DLC film 6.

DLC film 6 is generally a material with relatively high hardness among materials used in optical components, so it can exhibit high wear resistance. Due to its high hardness, DLC film 6 is not easily damaged when wiping off dirt attached to the surface. Therefore, the optical component 10 has excellent wear resistance when wiping off dirt attached to the outer surface by providing a DLC film 6 with high hardness on the outer surface.

In general, DLC film 6 has relatively high stability among materials used in optical components, and relatively low reactivity with other substances among materials used in optical components, so it can exert high corrosion resistance. The DLC film 6 has low reactivity with other substances, which can weaken the adhesion of foreign matter such as dust. Therefore, the optical component 10 is provided with a DLC film 6 with low reactivity with other substances on the outer surface, which makes it easy to remove foreign matter attached to the outer surface. In addition, the DLC film 6 has low reactivity with other substances and excellent stability in a corrosive environment. Therefore, the optical component 10 is provided with a DLC film 6 with low reactivity with other substances on the outer surface, which makes it possible to use it for a long time by suppressing degradation.

For example, when the optical component 10 is used as a protective window of a laser processing machine for opening holes in a printed circuit board, etc., the dust or metal splash generated during the hole opening process has a weak adhesion to the DLC film 6, so that the dirt does not adhere to the DLC film 6, and the dirt attached to the surface of the DLC film 6 can be easily removed. In addition, when the optical component 10 is used as a protective window of a laser processing machine for opening holes in a printed circuit board, etc., the DLC film 6 with excellent environmental resistance constitutes the outer surface of the optical component 10, and the corrosion of the optical component 10 caused by the influence of the gas generated during the hole opening process is suppressed, and the optical component 10 can be used for a long time.

Generally speaking, the adhesion between the Ge film 5 and DLC is relatively high among the materials used for optical components. Therefore, the optical component 10 can ensure the adhesion between the Ge film 5 and the DLC film 6 by making the Ge film 5 with excellent adhesion to the DLC film 6 contact the DLC film 6, thereby ensuring the adhesion between the Ge film 5 and the DLC film 6 and the adhesion between the multilayer film 7, and the adhesion between the substrate 1 and the multilayer film 7. In this way, the optical component 10 can suppress the peeling of the DLC film 6 caused by the compressive stress of the DLC film 6.

The Ge film 5 also has excellent adhesion to fluorides. That is, the Ge film 5 has relatively high adhesion to fluorides such as the YF ₃ film and the yttrium (III) fluoride (YbF ₃ ) film of the fluoride film 4 among materials generally used for optical components. Therefore, the optical component 10 can ensure the adhesion between the multilayer film 7 by making the Ge film 5 having excellent adhesion to the fluoride film 4 contact the fluoride film 4, thereby ensuring the adhesion between the Ge film 5 and the fluoride film 4, and can ensure the adhesion between the substrate 1 and the multilayer film 7. In this way, the optical component 10 can suppress the peeling of the DLC film 6 caused by the compressive stress of the DLC film 6.

Generally speaking, the adhesion of the fluoride film 4 to ZnSe is relatively high among materials used for optical components. That is, the adhesion of fluorides such as YF ₃ film and YbF ₃ film to ZnSe is relatively high among materials generally used for optical components. Therefore, the optical component 10 ensures the adhesion between the fluoride film 4 and the substrate 1 composed of ZnSe by bringing the fluoride film 4 having excellent adhesion to the substrate 1 composed of ZnSe into contact with the substrate 1 composed of ZnSe, thereby ensuring the adhesion between the fluoride film 4 and the substrate 1 composed of ZnSe, and thus ensuring the adhesion between the substrate 1 and the multilayer film 7.

In addition, the optical component 10 may have a fluoride film 4 other than the YF ₃ film instead of the YF ₃ film. The optical component 10 may also have a YbF ₃ film as the fluoride film 4. In the case where the YbF ₃ film is provided instead of the YF ₃ film, the optical component 10 can ensure the adhesion within the multilayer film 7 and the adhesion _between the substrate 1 and the multilayer film 7 by the high adhesion between the Ge film 5 and the YbF ₃ film and the high adhesion between the substrate 1 composed of ZnSe and the YbF 3 film.

Furthermore, the fluoride film 4 may be doped with elements other than Y, F, and Yb as long as it does not affect the optical performance and mechanical properties of the optical component 10. That is, the YF ₃ film and the YbF ₃ film as the fluoride film 4 may be doped with elements other than Y, F, and Yb as long as it does not affect the optical performance and mechanical properties of the optical component 10.

Therefore, the optical component 10 can improve the adhesion of the entire multi-layer film 7 by stacking the DLC film 6, the Ge film 5 and the fluoride film 4 in this order and adhering to each other.

Moreover, Ge generally has a relatively high transmittance for infrared light among materials used in optical components. The optical component 10 has a Ge film 5, such as the Ge film 5 described above, which exerts high adhesion between the DLC film 6 and the fluoride film 4 and improves the adhesion of the multilayer film 7 as a whole, and can also allow infrared light to pass through with high transmittance.

The method of forming the multilayer film 7 may be any method as long as the fluoride film 4, the Ge film 5 and the DLC film 6 can be formed on the substrate 1. The multilayer film 7 may be formed by generally known film forming methods such as physical vapor deposition (PVD) such as vacuum deposition and sputtering, and chemical deposition such as plasma CVD (Chemical Vapor Deposition; Chemical Vapor Deposition) method.

In the multilayer film 7, the thickness of the fluoride film 4 is set to be within the range of 700nm to 1100nm, the thickness of the Ge film 5 is set to be within the range of 15nm to 70nm, and the thickness of the DLC film 6 is set to be within the range of 50nm to 300nm. In this way, the optical component 10 utilizes the effect of interference from light and can transmit infrared light with high transmittance.

The optical component 10 can ensure the adhesion of the entire multilayer film 7 and the adhesion between the multilayer film 7 and the substrate 1 by setting the thickness of each layer of the multilayer film 7 to the above range, and can prevent the peeling of each layer in the multilayer film 7 and the peeling of the multilayer film 7 from the substrate 1 by using the tensile stress of the fluoride film 4 to offset the compressive stress of the DLC film 6. In addition, the optical component 10 can achieve a transmittance of 97% or more for _CO2 laser light having a wavelength of 9 μm or more and 11 μm or less by having a substrate 1 made of ZnSe and a multilayer film 7 having each layer having a thickness set within the above range. In this way, the optical component 10 can meet the optical properties required for the protective window of a laser processing machine.

When the optical component 10 is used as a protective window of a laser processing machine, and laser processing is continuously performed by the laser processing machine, the more the infrared laser light in the optical component 10 is absorbed, the more likely it is that a temperature distribution will occur in the substrate 1, and the refractive index distribution caused by the thermal lens effect due to this temperature distribution will occur in the optical component 10. Due to the refractive index distribution caused by the thermal lens effect, the refractive index of the center portion in the in-plane direction of the substrate 1 of the optical component 10 is greater than the refractive index of the outer side, and the optical component 10 has properties like a biconvex lens. Due to such a thermal lens effect, the diffusion angle of the laser light in the optical component 10 changes, and the focal position changes, making it difficult to process with high processing accuracy.

In laser processing machines, in order to prevent the decrease in processing accuracy due to such a thermal lens effect, the laser processing speed can be limited to obtain the necessary processing accuracy. However, in this case, the productivity of the laser processing machine is reduced by limiting the processing speed.

The optical component 10 has a substrate 1 made of ZnSe that can obtain high transmittance of laser light in the infrared region as an optical component, so that the thermal lens effect can be suppressed. As a result, a laser processing machine having the optical component 10 can suppress the occurrence of changes in the refractive index distribution in the optical component 10, making it possible to process with high processing accuracy, and preventing the reduction of the productivity of the laser processing machine.

In addition, the substrate 1 may be doped with elements other than ZnSe as long as it does not affect the optical performance of the optical component 10 or the mechanical properties of the laser processing machine. Each layer constituting the multilayer film 7 may also be doped with elements other than the crystallized elements of the layer as long as it does not affect the optical performance of the optical component 10 or the mechanical properties of the laser processing machine.

Furthermore, as long as the optical performance of the optical component 10 and the multilayer film 7 or the mechanical properties of the laser processing machine are not affected, the multilayer film 7 may also have thin films other than the above-mentioned constituent layers formed in the inner layer. However, when an oxide film such as a _{Y2O3 film} is provided in the inner layer of the multilayer _film 7, the _Y2O3 film has a high absorption rate of infrared light, which becomes a factor that reduces the transmittance of infrared light in the optical component 10. Therefore, when an oxide film is provided in the inner layer of the multilayer film 7, the film thickness of the oxide film is set to 30nm as the maximum film thickness, and it is preferably 20nm or less in practice. When two layers of oxide film are provided, it is preferably set to 10nm or less for each layer.

As long as it does not affect the optical performance of the optical component 10 or the mechanical properties of the laser processing machine, the optical component 10 may also be provided with layers other than the layers shown in FIG. 1. In addition, the optical component 10 may be provided with a multilayer film 7 on the first surface 2 of the first surface 2 and the second surface 3, and a film other than the multilayer film 7 may be provided on the second surface 3 to replace the multilayer film 7.

FIG. 2 is a cross-sectional view showing other structures of the optical component related to the embodiment 1. The optical component 11 shown in FIG. 2 has an anti-reflection film 8 provided on the second surface 3 of the substrate 1. The anti-reflection film 8 is formed by laminating a YF ₃ film, a Ge film, and a magnesium fluoride (MgF ₂ ) film in order from the second surface 3. In FIG. 2, the illustration of each layer constituting the anti-reflection film 8 is omitted. However, the structure of the anti-reflection film 8 is not limited to this variant, and any anti-reflection film 8 can be used as long as it has an anti-reflection function.

The optical component 11 is configured to suppress reflection of light incident on the optical component 11 by providing an anti-reflection film 8 on the second surface 3 of the substrate 1 on the light incident side. When the optical component 11 is used as a protective window of a laser processing machine, the optical component 11 can exhibit high environmental resistance to withstand the environment during laser processing by providing a DLC film 6 on the outer surface of the optical component 11 facing the object to be processed.

The method for forming the anti-reflection film 8 may be any method as long as the various layers of the anti-reflection film 8 can be formed on the substrate 1. For the formation of the anti-reflection film 8, generally known film forming methods such as physical vapor deposition such as vacuum deposition and sputtering, and chemical deposition such as plasma CVD can be used.

Therefore, when the optical components 10 and 11 according to the embodiment 1 are used as a protective window of a laser processing machine, a multilayer film 7 is provided on at least one of the first surface 2 and the second surface 3 of the substrate 1 composed of ZnSe in such a way that the DLC film 6 is arranged on the outer surface of the optical components 10 and 11 facing the workpiece.

Next, the embodiment 1 of the embodiment 1 is described. The optical component of the embodiment 1 is an optical component 11 having a multilayer film 7 provided on the first surface 2 and an antireflection film 8 provided on the second surface 3. The fluoride film 4 of the multilayer film 7 is a _MgF2 film. The antireflection film 8 has a transmittance of 99.5% or more for _CO2 laser light having a wavelength of 9.3 μm.

In the anti-reflection film 8 of Example 1, the thickness of the _MgF2 film is set to 200nm, the thickness of the Ge film is set to 55nm, and the thickness of the _YF3 film is set to 980nm. In the multilayer film 7, the thickness of the _MgF2 film of the fluoride film 4 is set to 810nm, the thickness of the Ge film 5 is set to 30nm, and the thickness of the DLC film 6 is set to 250nm. The _MgF2 film of the fluoride film 4, the Ge film 5 and the anti-reflection film 8 are formed by vacuum deposition. The DLC film 6 is formed by sputtering. The shape of the substrate 1 is a circular plate with a diameter of 90mm and a thickness of 5mm. The transmittance is evaluated using a Fourier transform infrared spectrophotometer.

FIG. 3 is a diagram showing an example of the wavelength dependence of the transmittance in the optical component related to the embodiment 1. FIG. 3 shows the wavelength dependence of the optical component 11 when the optical analysis is performed on the optical component 11 of the embodiment 1. In the optical analysis, the thin film calculation software Essential Macleod is used. The vertical axis of the graph shown in FIG. 3 represents the transmittance, and the horizontal axis represents the wavelength of light. According to the wavelength dependence shown in FIG. 3, a transmittance of 98.2% is achieved for a wavelength of 9.3μm. Since the transmittance of the protective window of the laser processing machine is preferably 97% or more, the optical component 11 satisfies the optical properties required for the protective window of the laser processing machine.

Here, a comparative example of Example 1 is described. The optical component of the comparative example is an optical component having a layer structure corresponding to the layer structure described in Patent Document 1. The optical component of the comparative example is an optical component having a substrate made of ZnS and two _Y2O3 films. On the main surface of the ZnS substrate, a first _{Y2O3 film} , a _YF3 film, a second _Y2O3 film, a Ge film and a _DLC film are sequentially layered from the main surface. The thickness of the first _Y2O3 film is set to 30nm, the thickness _of the _YF3 film is set to 600nm, the thickness of the _{second Y2O3} film is set to 30nm, the thickness of _the Ge film is set to 30nm and the thickness of the DLC film is set to 300nm. The thickness of the ZnS substrate is set to 5mm. A _Y2O3 film, a _YF3 film, and a _MgF2 film are sequentially laminated on the surface of the ZnS substrate facing the opposite side to the main surface. The thickness of the _Y2O3 film is 80nm, the thickness of _{the YF3 film} is 1300nm, and the thickness of the MgF2 _film is 400nm. In addition, the optical components of the comparative example are omitted from the figure.

FIG. 4 is a graph showing the wavelength dependence of transmittance in the optical component of the comparative example of implementation form 1. The vertical axis of the graph shown in FIG. 4 represents transmittance, and the horizontal axis represents the wavelength of light. The wavelength dependence shown in FIG. 4 is the result of optical analysis of the optical component using the thin film calculation software Essential Macleod. According to the wavelength dependence shown in FIG. 4, the transmittance at a wavelength of 9.3μm is less than 95%. When the optical component of the comparative example is used as a protective window of a laser processing machine, a thermal lens effect occurs, resulting in problems such as deterioration of processing accuracy during high-speed processing. That is, the optical component of the comparative example does not meet the optical properties required for the protective window of the laser processing machine.

As described above, the optical component 11 in Example 1 can be said to have achieved an improvement in optical performance compared to the optical component in the comparative example.

Compared with the optical component of the comparative example, the optical component 11 of the embodiment 1 can transmit infrared light with high transmittance, thereby reducing the local temperature rise from light absorption. That is, the optical component 11 of the embodiment 1 is not prone to thermal lens effect. By using the optical component 11 of the embodiment 1 in the protective window, the laser processing machine can perform high-precision processing.

According to the first embodiment, the optical components 10 and 11 have a multilayer film 7 formed by stacking three layers of a fluoride film 4, a Ge film 5, and a DLC film 6 in this order from the substrate 1 side, and can improve the transmittance of infrared light compared to the case where two _Y2O3 films are stacked on the first surface _2. In this way, the optical components 10 and 11 are configured without using oxides, and can achieve the effect of transmitting infrared light with high transmittance.

Implementation form 2

FIG. 5 is a diagram showing the schematic structure of a laser processing machine related to implementation form 2. The laser processing machine 20 irradiates the laser beam 22 toward the workpiece 25 to process the workpiece 25.

The laser processing machine 20 shown in FIG. 5 has: a laser oscillator 21, which is a laser light source that generates laser light 22; a lens system that transmits the laser light 22; and a protective window 24 that allows the laser light 22 to pass through. The lens system includes a focusing lens 23 that focuses the laser light 22. In FIG. 5, the illustration of lenses other than the focusing lens 23 in the lens system is omitted.

The protective window 24 is the optical component 10, 11 related to the implementation form 1. The laser oscillator 21 is a _CO2 laser. The laser processing machine 20 performs laser processing such as opening processing or cutting processing. _CO2 laser has the characteristics of being able to oscillate with high output and being able to oscillate in laser light with high absorption rate of resin, so the laser processing machine 20 is suitable for opening processing to printed circuit boards. In the laser processing machine 20, the laser light 22 emitted from the laser oscillator 21 is focused by the focusing lens 23, penetrates the protective window 24 and irradiates the workpiece 25 such as the printed circuit board, thereby realizing laser processing such as opening processing or cutting processing.

The protective window 24 is provided at the exit end of the laser beam 22 to the outside of the laser processing machine 20. The protective window 24 is located between the focusing lens 23 and the workpiece 25. The main surface of the protective window 24 is sometimes arranged close to the workpiece 25 in order to realize the small-diameter hole processing. The protective window 24 is sometimes close to a position about 100 mm away from the workpiece 25 during processing. Therefore, the protective window 24 becomes exposed to the environment where dust or spray generated during laser processing is scattered.

In the laser processing machine 20, the configuration of the protective window 24 is such that the first surface 2 of the substrate 1 faces the workpiece 25, and a DLC film 6 is provided on the outer surface of the protective window 24 facing the workpiece 25. The protective window 24 can exhibit high environmental resistance to the environment during laser processing by providing the DLC film 6 on the outer surface facing the workpiece 25.

The protective window 24 is arranged at the position closest to the workpiece 25 among all the optical components constituting the laser processing machine 20. That is, there is no optical component between the workpiece 25 and the protective window 24. Therefore, in the case of a refractive index distribution caused by the thermal lens effect, it is difficult for the protective window 24 to compensate for the refractive index distribution by introducing a new optical component or a mechanism for feeding back the output of the laser light 22. Due to this, the protective window 24 is required to have both environmental resistance and high penetration of the laser light 22.

By using the optical components 10 and 11 of the first embodiment, the protective window 24 can achieve the optical properties required for the protective window 24 without adding an element for compensating the refractive index distribution.

The laser processing machine 20 uses the optical components 10 and 11 of the embodiment 1 in the protective window 24, so that high-precision processing is still possible even without setting a limit on the processing speed to improve the processing accuracy. In this way, the laser processing machine 20 can achieve high-yield and high-precision processing without setting a limit on the processing speed.

In addition, the optical component 10 of the embodiment 1 has a multilayer film 71 of the multilayer film 7 on the first surface 2 of the substrate 1, and a multilayer film 72 of the multilayer film 7 on the second surface 3 of the substrate 1, and has a shape and structure that are symmetrical in the direction of the central axis of the disk shape of the substrate 1. Therefore, when the optical component 10 is used as a protective window 24 of a laser processing machine 20, either the first surface 2 or the second surface 3 can be set as the side of the object 25 to be processed.

As described above, according to embodiment 2, the laser processing machine 20 can obtain high environmental resistance and high optical properties by having the optical components 10 and 11 of embodiment 1. In this way, the laser processing machine 20 can maintain an appropriate life for the protective window 24 and achieve high-precision laser processing.

Implementation form 3

In embodiment 3, a laser processing machine for an optical component and a coating component is described, wherein the first surface 2 of a substrate 1 made of ZnSe is covered by a multilayer film 7 or a portion of the multilayer film 7 is not exposed. FIG. 6 is a cross-sectional view showing the structure of an optical component related to embodiment 3. The optical component 12 shown in FIG. 6 has: a substrate 1 made of ZnSe; a multilayer film 71, which is a multilayer film 7 provided on the first surface 2 of the main surface of the substrate 1; and a multilayer film 72, which is a multilayer film 7 provided on the second surface 3 of the substrate 1, and the second surface 3 is a surface facing the opposite side to the side facing the first surface 2. In addition, FIG. 6 assigns the same symbols as those of embodiment 1 and embodiment 2 for the same structure as the above-mentioned embodiment 1 and embodiment 2.

Here, in the optical component 12, the first surface 2 of the ZnSe substrate 1 is covered by the multilayer film 7 without being exposed. That is, the optical component 12 covers the entire first surface 2 of the ZnSe substrate 1 by the multilayer film 7. In addition, the first surface 2 may also be covered entirely by a portion of the multilayer film 7.

ZnSe is used in optical components because of its high infrared light transmittance, but it is a poison and must be handled with care. Therefore, in optical components that use ZnSe as a substrate material, it is necessary to pay careful attention to the handling of ZnSe abrasion powder generated by the abrasion of the substrate made of ZnSe and the jig that fixes the optical component.

FIG. 7 is a diagram showing a schematic structure of a laser processing machine related to the third embodiment. The laser processing machine 30 irradiates the laser beam 22 to the object 25 to be processed, and processes the object 25. In the following, the structure different from the second embodiment is mainly described.

The laser processing machine 30 has a barrel 31, which is a covering member. The barrel 31 covers the outer periphery of the focusing lens 23 and the outer periphery of the protective window 24. The protective window 24 is provided at the end of the barrel 31 on the side where the laser light 22 is emitted. The focusing lens 23 is arranged inside the barrel 31. By providing the barrel 31, the laser processing machine 30 can prevent dust or splash generated when processing the workpiece 25 from being attached to the focusing lens 23. The covering member is not limited to the barrel 31 as long as it can prevent dust or splash from being attached to the focusing lens 23. The material and shape of the covering member can be any material and shape that can prevent dust or splashing matter from adhering to the focusing lens 23.

FIG. 8 is a cross-sectional view showing the details of the setting environment of the protective window in the laser processing machine related to the implementation form 3. In FIG. 8, the multilayer film 71 provided on the first surface 2 of the substrate 1 and the multilayer film 72 provided on the second surface 3 of the substrate 1 or the anti-reflection film 8 provided on the second surface 3 of the substrate 1 are omitted. The protective window 24 is located between the lens barrel 31 and the cover 32. The protective window 24 is a case of the optical component 10 related to the implementation form 1, and the friction between the first surface 2 of the ZnSe substrate 1 of the protective window 24 and the lens barrel 31 generates abrasion powder.

In the embodiment 3, the optical component 12 is used as the protective window 24, which makes it possible to reduce or prevent the generation of ZnSe abrasion powder. That is, by covering the first surface 2 of the ZnSe substrate 1 with the multilayer film 7 or a part of the multilayer film 7 without being exposed, the first surface 2 of the substrate 1 and the lens barrel 31 will not be in direct contact, which can reduce or prevent the generation of poisonous ZnSe abrasion powder.

In addition, regarding the raw material of the cover 32, a soft raw material such as resin can be selected. Therefore, in the third embodiment, the generation of ZnSe wear powder caused by the friction between the cover 32 and the protective window 24 can be more reliably reduced or prevented.

The laser processing machine 30 is configured as described above, and can still maintain a high degree of transmittance of light of a specific wavelength to improve maintainability and safety.

When the DLC film 6 is formed by CVD, the entire first surface 2 of the ZnSe substrate 1 can be covered without being exposed by the DLC film 6. On the other hand, when the DLC film 6 is formed by PVD represented by sputtering, a region where the DLC film 6 is not formed will be generated on the first surface 2 by a jig for holding the substrate 1.

FIG. 9 is a cross-sectional view of a substrate and a jig viewed from the side when a multi-layer film is formed on a substrate by the PVD method in Embodiment 3. FIG. 10 is a top view of a jig related to Embodiment 3. As shown in FIG. 9, when a multi-layer film 7 is formed on the first surface 2 of the substrate 1 by the PVD method, the substrate 1 is held by a film forming jig 41.

The film forming jig 41 has a ring shape whose inner diameter is larger than the outer circumference of the disc-shaped substrate 1. The film forming jig 41 has two holding parts 41a extending from the bottom side of the inner circumference of the ring shape to the inner side of the ring shape to hold the substrate 1. The two holding parts 41a are arranged at opposite positions in the ring shape of the film forming jig 41. The film forming jig 41 holds the substrate 1 by placing the substrate 1 on the holding parts 41a.

In FIG. 9, the multi-layer film 7 is formed on the substrate 1 by the PVD method, and the process is performed on the first surface 2 from the lower side in FIG. 9. At this time, the contact portion between the first surface 2 of the substrate 1 and the holding portion 41a of the film forming jig 41 becomes a non-film forming area 2a.

As shown in FIG. 10, the formation area of the holding portion 41a of the film forming jig 41 is not the entire inner circumference of the film forming jig 41 having a ring shape, but is limited to a portion of the inner circumference of the film forming jig 41. In the film forming of the multi-layer film 7 on the substrate 1 by the PVD method, the area where the film is formed on the first surface 2 of the substrate 1 can be widened. In addition, when the film forming jig 41 is used in the film forming of the multi-layer film 7 on the substrate 1 by the PVD method, the film can also be formed on the outer circumference of the area where the first surface 2 of the substrate 1 is not in contact with the holding portion 41a.

Next, the film forming step of forming a multilayer film 7 onto the substrate 1 by the PVD method in the third embodiment is described. FIG. 11 is a first figure illustrating the film forming step of forming a multilayer film onto the substrate by the PVD method in the third embodiment. FIG. 12 is a second figure illustrating the film forming step of forming a multilayer film onto the substrate by the PVD method in the third embodiment. FIG. 13 is a third figure illustrating the film forming step of forming a multilayer film onto the substrate by the PVD method in the third embodiment. FIG. 11 to FIG. 13 show the state of the first surface 2 side of the substrate 1 in the film forming step of forming a multilayer film 7 onto the substrate 1 by the PVD method. In addition, in FIG. 11 to FIG. 13, the description of the film forming jig 41 including the holding portion 41a is omitted.

First, prepare a substrate 1 with the first surface 2 exposed as shown in FIG. 11. The substrate 1 is held by a film forming jig 41. The substrate 1 is held by being placed on two holding portions 41a.

First, a fluoride film 4 and a Ge film 5 are sequentially formed on the first surface 2. At a point in time after the formation of the Ge film 5 is completed, as shown in FIG. 12, the first surface 2 is exposed in a region held in a portion of the holding portion 41a in the first surface 2.

When forming the subsequent DLC film 6, the substrate 1 is rotated inside the film forming jig 41 in the in-plane direction of the first surface 2, with the central axis in the circle of the first surface 2 as the rotation axis. Thereby, the position of the substrate 1 relative to the film forming jig 41 in the in-plane direction of the first surface 2 is changed with the central axis in the circle of the first surface 2 as the center. Then, the DLC film 6 is formed on the fluoride film 4 and the Ge film 5 while the substrate 1 is rotated.

Thus, as shown in FIG. 13, the DLC film 6 can be formed by the PVD method without exposing the first surface 2. According to the above method, the film forming method is not limited, and the existing DLC film forming device can be used to cover the first surface 2 of the ZnSe substrate 1 by the multilayer film 7 or any film layer in the multilayer film 7 without exposing it, so that the optical component 12 can be formed economically.

Then, according to the optical component 12, which is formed by covering the first surface 2 of the ZnSe substrate 1 with the multilayer film 7 or any layer in the multilayer film 7 without being exposed, the generation of ZnSe abrasion powder caused by the wear of the lens barrel 31 of the jig fixing the optical component 12 having the ZnSe substrate 1 and the first surface 2 of the substrate 1 can be reduced or prevented.

According to the third embodiment, the laser processing machine 30 can obtain higher environmental resistance and high optical properties by having the optical component 12 and the lens barrel 31 of the third embodiment.

Implementation form 4

In implementation form 4, a laser processing machine having a structure of cooling optical components is described in order to further suppress the reduction in processing accuracy caused by the thermal lens effect.

Regarding the material of the substrate 1 that can be used for the protective window 24 having high transmittance of _CO2 laser light having a wavelength of 9.3μm, in addition to ZnSe, which is a material with relatively high transmittance of infrared light among optical materials, there is Ge. Compared with Ge, ZnSe is easier to obtain. On the other hand, compared with Ge, the thermal conductivity of ZnSe is lower. Therefore, in the comparison between the case where ZnSe is used as the material of the substrate 1 for the protective window 24 and the case where Ge is used as the material of the substrate 1 for the protective window 24, uneven heat distribution inside the substrate 1 during laser processing, that is, uneven temperature distribution inside the substrate 1 during laser processing is likely to occur. When there is non-uniform heat distribution inside the substrate 1 of the protective window 24, that is, when there is non-uniform temperature distribution inside the substrate 1 of the protective window 24, a refractive index distribution due to the heat lens effect caused by the temperature distribution occurs in the substrate 1. The refractive index distribution caused by the non-uniform temperature distribution inside the substrate 1 of the protective window 24 becomes a factor that reduces the processing accuracy of the laser processing machine.

FIG. 14 is a diagram showing a schematic structure of a laser processing machine related to implementation form 4. FIG. 15 is a block diagram showing the functional structure of a laser processing machine related to implementation form 4. The laser processing machine 30a related to implementation form 4 has a structure in which a cooling air device 50 is added to the laser processing machine 30 related to implementation form 3. That is, the laser processing machine 30a irradiates the laser light 22 to the workpiece 25 to process the workpiece 25. In the following, the structure different from the laser processing machine 30 related to implementation form 3 is mainly described.

The cooling air device 50 has an air supply unit 51, an air supply communication unit 52, an air supply memory unit 53 and an air supply control unit 54. The above-mentioned components of the cooling air device 50 are configured to be able to send and receive information. The air supply unit 51 blows cooling air to the side of the protective window 24 facing the workpiece 25. The air supply communication unit 52 communicates between the cooling air device 50 and external machines. The air supply memory unit 53 stores various information used to control the cooling air device 50.

The air supply control unit 54 controls the operation of the cooling device 50. The air supply control unit 54 controls the operation of the cooling device 50 based on the action instruction information or the program pre-stored in the air supply memory unit 53. The air supply control unit 54 receives the action instruction information sent from the external machine of the cooling device 50 through the air supply communication unit 52. That is, the air supply control unit 54 controls the operation of the cooling device 50 such as the operation, stop, and adjustment of the air volume of the cooling device 50 based on the action instruction information or the program pre-stored in the air supply memory unit 53.

The laser processing machine 30a has a lens barrel 31 as the same as the laser processing machine 30 related to the embodiment 3, and the lens barrel 31 is a covered component. The protective window 24 is provided at the end of the laser light 22 emission side in the lens barrel 31 as in the laser processing machine 30. Moreover, the protective window 24 is covered by the lens barrel 31 as in the laser processing machine 30, with the multilayer film 71 of the multilayer film 7 provided on the first surface 2 of the main surface of the substrate 1 facing the workpiece 25, the multilayer film 72 of the multilayer film 7 provided on the second surface 3 of the substrate 1, or the anti-reflection film 8 provided on the second surface 3 of the substrate 1 facing the focusing lens 23 side.

The cooling air device 50 cools the protective window 24 by supplying cooling air from the outside of the lens barrel 31 to the protective window 24. The cooling air device 50 supplies cooling air to the protective window 24 from the side of the lens barrel 31 where the laser light 22 is emitted. That is, the cooling air device 50 supplies cooling air to the side of the protective window 24 facing the workpiece 25 from the space between the lens barrel 31 and the workpiece 25 in the direction of the central axis of the laser light 22. In this way, in the protective window 24, the cooling air supplied from the cooling air device 50 is blown to the entire side of the protective window 24 facing the workpiece 25 outside the area held by the lens barrel 31.

The protective window 24 is cooled by the cooling wind, and the occurrence of temperature distribution inside the substrate 1 of the protective window 24 during laser processing is suppressed. Thus, the protective window 24 suppresses the occurrence of refractive index distribution in the substrate 1 due to the thermal lens effect of the temperature distribution inside the substrate 1 of the protective window 24 during laser processing. That is, the protective window 24 is blown by the cooling wind, and the occurrence of refractive index distribution in the substrate 1 during laser processing is suppressed.

Thus, the laser processing machine 30a can maintain a certain processing accuracy by blowing cooling air to the protective window 24, suppressing the occurrence of the refractive index distribution in the substrate 1 due to the thermal lens effect caused by the temperature distribution inside the substrate 1 of the protective window 24 during laser processing. That is, the laser processing machine 30a can maintain a certain processing accuracy by cooling the protective window 24 by the cooling air during laser processing, suppressing the refractive index distribution in the substrate 1 due to the thermal lens effect.

The cooling air device 50 is not particularly limited as long as it can supply cooling air from the outside of the lens barrel 31 to the protective window 24. The cooling air device 50 may also use an air conditioning device for local cooling called a spot cooler.

For example, suppose that a cooling mechanism is provided in the lens barrel 31, which is the holding part of the protective window 24. In this case, the central part of the protective window 24 is at a higher temperature during laser processing, and the outer peripheral part of the protective window 24 in the plane direction perpendicular to the central axis of the laser light 22 is cooled by the cooling mechanism. Therefore, there is a risk that the uneven heat distribution inside the substrate 1 of the protective window 24 will increase. In this case, the cooling mechanism becomes a large-scale structure, and there are disadvantages such as the cooling cost of the protective window 24 becomes high.

On the other hand, regarding the cooling mechanism of the protective window 24 by cooling wind of the laser processing machine 30a of the third embodiment, the flat shape of the protective window 24 is utilized to uniformly cool a relatively wide surface of the outer shape of the protective window 24, that is, the surface facing the workpiece 25. Thus, the surface facing the workpiece 25 is uniformly cooled by the cooling wind and the temperature is lowered. Then, the heat of the temperature drop caused by the cooling wind is conducted to the thickness direction of the outer shape of the protective window 24, which is relatively small, so that the entire protective window 24 can be uniformly cooled. That is, the heat of the entire protective window 24 is absorbed to the surface direction of the side opposite to the workpiece 25 where the temperature is lowered by the cooling air, and the entire protective window 24 can be uniformly cooled.

Next, the structure after the cooling air device 50 is connected to the control device 60 of the other laser processing machine 30b is described. Figure 16 is a diagram showing the schematic structure of the other laser processing machine related to the implementation form 4. Figure 17 is a block diagram showing the functional structure of the control device of the other laser processing machine related to the implementation form 4.

The control device 60 controls the actions of other laser processing machines 30b and the cooling air device 50 to control the laser processing of the laser processing machine 30b. The control device 60 has a control device communication unit 61, a control device memory unit 62, and a control device control unit 63.

The control device communication unit 61 communicates between other laser processing machines 30b and external machines. The control device communication unit 61 communicates with the cooling air device 50. The control device memory unit 62 stores various information for controlling the entire other laser processing machines 30b including the cooling air device 50. The various information includes a processing formula for enabling the control device control unit 63 to realize the control of the entire other laser processing machines 30b.

The control device control unit 63 controls the entire operation of the laser processing machine 30b including the control of the cooling air device 50. The control device control unit 63 includes a laser control unit 631 and a cooling air control unit 632.

The laser control unit 631 controls the laser processing operation in other laser processing machines 30b including the operation of the laser oscillator 21.

The cooling air control unit 632 controls the operation of the cooling air device 50. The cooling air control unit 632 is linked to the laser processing operation in other laser processing machines 30b, and controls the operation of the cooling air device 50 when the laser processing in other laser processing machines 30b is being performed. That is, when the laser oscillator in other laser processing machines 30b oscillates the laser, the cooling air control unit 632 controls the air supply control unit 54 of the cooling air device 50 to operate the cooling air device 50. The air supply control unit 54 performs the air supply operation according to the control of the cooling air control unit 632.

The cooling air supplied by the cooling air device 50 is supplied to the protective window 24 for the purpose of cooling the heat generated in the protective window 24 due to the heat absorption during the laser processing in the protective window 24. Therefore, the cooling air device 50 does not need to generate cooling air when the other laser processing machine 30b is not performing laser processing.

Therefore, the cooling air control unit 632 can control the operation and air supply conditions of the cooling air device 50 according to the operating state of the other laser processing machine 30b, that is, the state of laser processing. Therefore, the air supply control unit 54 of the cooling air device 50 can control the operation and air supply conditions of the cooling air device 50 according to the operating state of the other laser processing machine 30b, that is, the state of laser processing. Therefore, the cooling air device 50 does not always use energy by supplying air when the other laser processing machine 30b is not performing laser processing, and can supply the necessary amount of cooling air to the protective window 24 when necessary. Thereby, the other laser processing machine 30b can realize energy-saving and high-precision laser processing. The air supply conditions of the cooling air device 50 include the air volume and temperature of the cooling air supplied by the cooling air device 50.

The cooling air control unit 632 controls the operation and air supply conditions of the cooling air device 50 according to the operating state of other laser processing machines 30b. For example, based on the information of the laser light delivery state of the laser oscillator 21, the operation and air supply conditions of the cooling air device 50 can be controlled. The cooling air control unit 632 obtains the information of the laser light delivery state from the laser control unit 631.

In addition, the cooling air control unit 632 controls the operation and air supply conditions of the cooling air device 50 in accordance with the operating state of the other laser processing machine 30b. For example, based on the processing formula used to realize the laser processing of the other laser processing machine 30b, the operation and air supply conditions of the cooling air device 50 can be controlled. The cooling air control unit 632 can find out the delivery state of the laser light by analyzing the processing formula. The cooling air control unit 632 obtains the processing formula from the control device memory unit 62.

The air supply control unit 54 of the cooling air device 50 and the control unit control unit 63 of the control unit 60 are each implemented as a processing circuit having a hardware configuration such as shown in FIG. 18. FIG. 18 is a diagram showing an example of a hardware configuration of a processing circuit related to the embodiment 4. The air supply control unit 54 of the cooling air device 50 and the control unit control unit 63 of the control unit 60 are respectively implemented by the processing circuit shown in FIG. 18. The air supply control unit 54 of the cooling air device 50 and the control unit control unit 63 of the control unit 60 are each implemented by a processor 81 executing a program stored in a memory 82 shown in FIG. 18. In addition, the above functions may be implemented in combination with a plurality of processors and a plurality of memories. Furthermore, a part of the functions of the air supply control unit 54 of the cooling air device 50 and the control unit control unit 63 of the control device 60 may be assembled as an electronic circuit, and the other parts may be implemented using the processor 81 and the memory 82.

The configuration of the above-mentioned implementation form is only an example, and it is possible to combine with other known technologies, or to combine the implementation forms with each other. It is also possible to omit or change part of the configuration without departing from the main points.

1: Substrate

2: First side

3: Second side

4: Fluoride membrane

5:Ge film

6:DLC film

7,71,72: Multi-layer membrane

10: Optical components

Claims (7)

An optical component is characterized by comprising: a substrate composed of zinc selenide, having a first surface and a second surface, wherein the second surface faces the opposite side to the side faced by the first surface; a first multilayer film composed of at least three layers is arranged on the first surface, and is stacked in sequence from the substrate side with a fluoride film, a germanium film and a diamond-like carbon film, wherein the fluoride film is composed of yttrium fluoride or yttrium fluoride; and a second multilayer film is arranged on the second surface, and is stacked in sequence from the substrate side with a _YF3 film, a Ge film and a _MgF2 film. The optical component as recited in claim 1, wherein the entire first surface is covered with the first multi-layer film or any one of the first multi-layer films. An optical component as recited in claim 1, wherein in the first multi-layer film, the germanium film is connected to the diamond-like carbon film and the fluoride film. An optical component as described in claim 1, wherein in the first multi-layer film, the thickness of the fluoride film is in the range of 700 nm to 1100 nm, the thickness of the germanium film is in the range of 15 nm to 70 nm, and the thickness of the diamond-like carbon film is in the range of 50 nm to 300 nm. A laser processing machine is characterized by having: a laser light source for generating laser light; a focusing lens for focusing the laser light and irradiating the workpiece; and an optical component described in any one of claims 1 to 4, which is arranged between the focusing lens and the workpiece in a state where the diamond-like carbon film faces the workpiece and is penetrated by the laser light. The laser processing machine as recited in claim 5 is provided with a cooling air device for cooling the optical component by supplying air to the optical component during laser processing. As described in claim 6, the cooling air device controls the action and air supply conditions of supplying air to the optical component in accordance with the operating state of the laser processing machine.