WO2017195603A1 - Optical component and laser processing device - Google Patents

Abstract

An optical component characterized in that a fluoride film, a Ge film, and a diamond-like carbon film (DLC film) are laminated on at least one surface of a Ge substrate in the sequence listed from the Ge substrate side. The film thickness of the fluoride film is preferably 500-950 nm, the film thickness of the Ge film is preferably 50-150 nm, and the film thickness of the DLC film is preferably 50-300 nm. The fluoride film preferably comprises at least one substance selected from the group consisting of YF₃, YbF₃, and MgF₂.

Description

Optical components and laser processing machines

The present invention relates to an optical component and a laser processing machine equipped with the optical component.

The CO ₂ laser oscillated at a wavelength of 9 μm to 11 μm is capable of high-power oscillation and has a high absorption rate in resin, so it can be used for drilling holes in printed wiring boards built in electronic devices such as smartphones. Used.

In the laser processing machine for drilling, since the condensing lens is installed above the processing area, there is a problem that dirt is attached to the condensing lens due to resin vapor generated during processing, resin sputtering, copper sputtering, etc. is there. Conventionally, in order to prevent this, an optical component called a protective window (protective window) is disposed between the condensing lens and the workpiece to prevent damage and deterioration of the condensing lens. The main performance required for the protective window is that it is highly transmissive to CO ₂ laser, which is infrared light, and that it has wear resistance that can withstand wiping off adhered dust and spatter.

In Patent Document 1, a first Y ₂ O ₃ layer, a YF ₃ layer, a second Y ₂ O ₃ layer, and a diamond-like carbon layer are laminated in this order from the substrate surface on the surface side of a ZnS substrate. Infrared transmitting structure, and ZnS, Al ₂ O ₃ , Y ₂ O ₃ having a thickness of 10 to 200 nm and Ge layer having a thickness of 100 to 750 nm on the surface side of the ZnS substrate in order from the substrate surface. An infrared transmission structure in which a diamond-like carbon layer having a thickness of 500 to 2000 nm is laminated has been proposed.

According to Patent Document 1, it is said that an infrared transmission structure having excellent impact resistance and durability as compared with the conventional infrared transmission structure and having excellent peeling resistance and transmittance is realized.

JP 2008-268277 A

However, although the infrared transmitting structure proposed in Patent Document 1 has good wear resistance because a diamond-like carbon layer is formed on the outermost layer, it is sufficiently optical when used as an optical component of a laser processing machine. There was a problem that performance could not be obtained. When laser processing is carried out with a laser processing machine equipped with such an optical component, the optical component absorbs infrared light, a temperature distribution is generated on the ZnS substrate, and the laser transmission accuracy called the thermal lens effect. Decrease. In particular, in a laser drilling machine equipped with an optical component as a protective window, the optical lens absorbs infrared light and a thermal lens effect occurs, making it impossible to achieve the desired hole position and hole shape. There was a problem that non-standard defective products occurred. In order to prevent such problems, the laser processing machine for drilling has achieved the required processing accuracy by limiting the speed of laser processing. End up.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an optical component having a high transmittance with respect to CO ₂ laser light and excellent in wear resistance.

The present invention is an optical component characterized in that a fluoride film, a Ge film, and a diamond-like carbon film (DLC film) are laminated in this order on at least one surface of a Ge substrate from the Ge substrate side.

According to the present invention, it is possible to provide an optical component having excellent high transmittance has and abrasion resistance against CO ₂ laser light. Moreover, the laser processing machine equipped with the optical component of the present invention can perform high-precision processing even during high-speed processing.

2 is a schematic cross-sectional view showing a configuration of an optical component according to Embodiment 1. FIG. 6 is a schematic cross-sectional view showing another configuration of the optical component according to Embodiment 1. FIG. 6 is a schematic cross-sectional view showing a configuration of an optical component according to Embodiment 2. FIG. FIG. 6 is a schematic diagram illustrating a configuration of a laser beam machine according to a third embodiment. It is a figure which shows the wavelength dependence of the transmittance | permeability in the optical component of Example 1. FIG. It is a figure which shows the wavelength dependence of the transmittance | permeability in the optical component of the comparative example 1. It is a figure which shows the wavelength dependence of the transmittance | permeability in the optical component of Example 3. It is a figure which shows the wavelength dependence of the transmittance | permeability in the optical component of Example 4. It is a figure which shows the wavelength dependence of the transmittance | permeability in the optical component of Example 5. It is a figure which shows the wavelength dependence of the transmittance | permeability in the optical component of Example 6. It is a figure which shows the wavelength dependence of the transmittance | permeability in the optical component of Example 7. It is a figure which shows the wavelength dependence of the transmittance | permeability in the optical component of Example 8.

Embodiment 1 FIG.
The optical component according to Embodiment 1 of the present invention is characterized in that a fluoride film, a Ge film, and a diamond-like carbon film (DLC film) are laminated in this order on at least one surface of a Ge substrate from the Ge substrate side. It is what.

FIG. 1 is a schematic cross-sectional view showing a configuration of an optical component according to Embodiment 1. As shown in FIG. 1, the optical component includes a fluoride film 11 stacked on a Ge substrate 10, a Ge film 12 stacked on the fluoride film 11, and a DLC film stacked on the Ge film 12. 13 is provided on both sides of the Ge substrate 10. FIG. 2 is a schematic cross-sectional view showing another configuration of the optical component according to Embodiment 1. As shown in FIG. 2, the optical component includes a fluoride film 11 stacked on the Ge substrate 10, a Ge film 12 stacked on the fluoride film 11, and a DLC film stacked on the Ge film 12. 13 is provided on one surface of the Ge substrate 10, and an antireflection film 15 different from the multilayer film 14 is provided on the other surface of the Ge substrate 10.

In the optical component of Patent Document 1, ZnS is used as a substrate. However, when ZnS having a low thermal conductivity is used as a substrate, temperature distribution occurs in the substrate when laser processing is continuously performed. When such a temperature distribution occurs, the processing accuracy decreases due to the thermal lens effect, so that ZnS is not suitable as a substrate for optical components for laser processing machines.
Therefore, in the optical component of the present invention, Ge having high thermal conductivity is used for the substrate. The Ge substrate 10 may be doped with an element other than Ge as long as optical performance and mechanical properties are not affected. The shape of the Ge substrate 10 is not limited. For example, the protective window for a laser beam machine is preferably a disc having a diameter of 80 mm to 140 mm and a thickness of 2 mm to 10 mm.

The fluoride film 11 laminated on the Ge substrate 10 only needs to contain at least one of fluorides such as YF ₃ , YbF ₃ , MgF ₂ , BaF ₂ , CaF _{2, and the} like in the infrared region. From the viewpoint of excellent permeability, it is preferably made of at least one selected from the group consisting of YF ₃ , YbF ₃ and MgF ₂ .

When the film thickness of the fluoride film 11 increases, the tensile stress increases. Therefore, if the film thickness is too large, the fluoride film 11 may be damaged during the film formation of the fluoride film 11 to ensure the adhesion of the film. May be difficult to do. On the other hand, if the film thickness of the fluoride film 11 becomes too small, it becomes difficult to obtain an antireflection effect, and the transmittance of infrared light may decrease. The film thickness of the fluoride film 11 is preferably 500 nm to 950 nm from the viewpoint of realizing high transmittance with respect to infrared light while ensuring film adhesion.

Since the Ge film 12 laminated on the fluoride film 11 has good adhesion to the DLC film 13, the adhesion of the DLC film 13 can be ensured by providing the Ge film 12. By disposing the Ge film 12 between the DLC film 13 having a compressive stress and the fluoride film 11 having a tensile stress, the stress balance in the entire multilayer film 14 is maintained, and a fluorine film which is an interface having a weak adhesive force. This prevents a load from being applied between the fluoride film 11 and the Ge film 12 and between the fluoride film 11 and the Ge substrate 10.

If the film thickness of the Ge film 12 is too large, it becomes difficult to maintain the balance of stress in the entire multilayer film 14, and between the fluoride film 11 and the Ge film 12 and between the fluoride film 11 and the Ge substrate 10. Peeling easily occurs. On the other hand, when the film thickness of the Ge film 12 becomes too small, it is difficult to obtain an antireflection effect, and the transmittance of infrared light may be reduced. The film thickness of the Ge film 12 is preferably 50 nm to 150 nm, more preferably 100 nm to 130 nm, from the viewpoint of realizing high transmittance for infrared light while ensuring film adhesion. preferable.

The DLC film 13 laminated on the Ge film 12 is made of diamond-like carbon having high stability as a substance and low reactivity with other materials. By providing such a DLC film 13 on the outermost surface of the optical member, it is possible to prevent the film from being damaged or corroded by dust or spatter generated during drilling of a printed circuit board or the like. Furthermore, since diamond-like carbon has high hardness and adhesion of spatter to diamond-like carbon is weak, it is possible to easily remove spatter by cleaning the optical member without worrying about scratches. Optical parts can be easily recycled and reused.

If the film thickness of the DLC film 13 is too large, the absorption of infrared light by the DLC film 13 increases, the transmittance of infrared light decreases, the compressive stress increases, and the adhesion of the film also decreases. is there. On the other hand, if the thickness of the DLC film 13 becomes too small, the wear resistance inherent in the DLC film 13 may not be exhibited due to the influence of the base of the DLC film 13 during wear. Considering these points, the film thickness of the DLC film 13 is preferably 50 nm to 300 nm.

As long as the optical performance and mechanical properties of the multilayer film 14 are not affected, each of the above films may be doped with other elements, or a thin film other than the above films may be formed.

The antireflection film 15 is not limited, but for example, a YF ₃ film having a thickness of 600 nm to 800 nm, a Ge film having a thickness of 110 nm to 180 nm, and a thickness of 50 nm to 800 nm from the Ge substrate 10 side. MgF ₂ films having the above are stacked in this order. By providing such an antireflection film 15 on one surface of the Ge substrate 10 that serves as an incident surface of the laser light, a wavelength of 9.3 μm or a wavelength is obtained as compared with the case where the multilayer film 14 is provided on both surfaces of the Ge substrate 10. The transmittance at 10.6 μm can be improved.

As a method for forming the multilayer film 14 and the antireflection film 15 in the optical component of the present invention, any method can be used as long as it can form a film on the Ge substrate 10. As a generally known film forming method, a physical vapor deposition method (PVD method) such as a vacuum vapor deposition method or a sputtering method, and a chemical vapor deposition method (CVD method) such as a plasma CVD method can be given. In the present invention, the fluoride film 11, the Ge film 12, and the antireflection film 15 are preferably formed by a vacuum deposition method from the viewpoint of excellent production efficiency when a film is formed using a plurality of materials. In the present invention, the DLC film 13 is preferably formed by a plasma CVD method from the viewpoint that the composition and thickness of the film can be accurately adjusted.

According to the first embodiment, it is possible to provide an optical component that has a high transmittance with respect to a CO ₂ laser beam having a wavelength of 9 μm to 11 μm and is excellent in wear resistance.

Embodiment 2. FIG.
In the optical component according to the second embodiment, a fluoride film, a Ge film, and a DLC film are laminated in this order on at least one surface of the Ge substrate from the Ge substrate side, and the fluoride film and the Ge film are exposed. It is characterized by being covered with a DLC film.

FIG. 3 is a schematic cross-sectional view showing the configuration of the optical component according to the second embodiment. As shown in FIG. 3, in the optical component, the fluoride film 11 laminated on the Ge substrate 10, the Ge film 12 laminated on the fluoride film 11, the fluoride film 11 and the Ge film 12 are exposed. In order to prevent this, the multilayer film 20 including the fluoride film 11 and the DLC film 13 covering the Ge film 12 is provided on one surface of the Ge substrate 10, and the antireflection film 15 described in the first embodiment is the Ge substrate. 10 is provided on the other surface. In FIG. 3, the multilayer film 20 is provided on one surface of the Ge substrate 10, but the multilayer film 20 may be provided on both surfaces of the Ge substrate 10.

Since the Ge substrate 10, the fluoride film 11, the Ge film 12, and the antireflection film 15 are the same as those described in the first embodiment, their descriptions are omitted.

The film thickness of the DLC film 13 formed on the upper surface of the Ge film 12 is preferably 50 nm to 300 nm as in the first embodiment. The film thickness of the DLC film 13 formed so that the fluoride film 11 and the Ge film 12 are not exposed on the side surfaces of the fluoride film 11 and the Ge film 12 is a film in which the fluoride film 11 and the Ge film 12 are not exposed. It only needs to be thick. Such a DLC film 13 can be formed by adjusting the size of the opening of the mask when the film is formed by sputtering using the mask. By covering the fluoride film 11 and the Ge film 12 in the optical component with the DLC film 13, it is possible to exhibit excellent corrosion resistance against the gas generated during processing.

According to the second embodiment, it is possible to provide an optical component that has a high transmittance with respect to the CO ₂ laser light, has excellent wear resistance, and does not corrode by a gas generated during processing.

Embodiment 3 FIG.
A laser beam machine according to Embodiment 3 includes the optical component according to Embodiment 1 or 2 described above.

FIG. 4 is a schematic diagram showing the configuration of the laser processing machine according to the third embodiment. As shown in FIG. 4, the laser processing machine includes a laser oscillator 30, a condensing lens 32 that condenses the laser light 31 emitted from the laser oscillator 30, and a workpiece such as the condensing lens 32 and a printed wiring board. And a protective window 34 disposed in the middle of the optical path of the laser beam 31 with the object 33, and the optical component according to the first or second embodiment described above is used as the protective window 34. Here, the protective window 34 is installed so that the multilayer film 14 described in the first embodiment or the multilayer film 20 described in the second embodiment faces the processing space side (the workpiece 33 side). Note that the configuration of the laser processing machine shown in FIG. 4 is an example, and the configuration is not limited to this configuration as long as it includes a laser oscillator and an optical system.

In the laser processing machine configured as described above, the laser beam 31 emitted from the laser oscillator 30 is condensed by the condenser lens 32, passes through the protective window 34, and is then irradiated to the workpiece 33 to form a hole. Is possible.

Since the optical component according to Embodiment 1 or 2 described above has a high transmittance with respect to the CO ₂ laser beam, by using this as the protective window 34, the thermal lens effect caused by the absorption of the laser is prevented and processed. It is possible to realize a laser processing machine that can perform high-speed processing without causing a decrease in accuracy. In addition, since the protective window 34 is installed so that the multilayer films 14 and 20 having the DLC film 13 formed on the outermost surface face the processing space, the protective window 34 can be used for a long time without worrying about the generation of scratches. Dust and spatter adhering to the surface can be easily removed. Generally, since the protective window 34 can be separated from the workpiece 33 only by about 100 mm, the protective window 34 is exposed to a large amount of spatter and dust during processing. Since the optical component described in the second embodiment is also excellent in corrosion resistance, the life of the optical component of the laser beam machine can be improved by using it as the protective window 34.

According to the third embodiment, it is possible to provide a laser processing machine capable of improving the maintainability and performing high speed processing without causing a decrease in processing accuracy.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[Example 1]
As an optical component, a multilayer film (from the Ge substrate side, MgF ₂ film (thickness 500 nm) / Ge film (thickness 80 nm) / DLC film (thickness) is formed on one surface of the Ge substrate (surface to be a laser beam emission surface). 500 nm)), and an antireflection film (a YF ₃ film (film thickness 650 nm) / Ge film (film thickness 130 nm) / MgF ₂ film (from the Ge substrate side) on the other surface (the surface to which the laser beam is incident)) A protective window for a laser beam machine having a thickness of 200 nm)) was produced. As the Ge substrate, a disk having a diameter of 90 mm and a thickness of 5 mm was used. The MgF ₂ film and Ge film constituting the multilayer film and the antireflection film were formed by vacuum deposition, and the DLC film constituting the multilayer film was formed by sputtering. Moreover, the transmittance of the produced optical component was evaluated using a Fourier transform infrared spectrophotometer.
The configuration of the optical component produced in Example 1 is as follows: DLC film (film thickness 500 nm) / Ge film (film thickness 80 nm) / MgF ₂ film (film thickness 500 nm) / Ge substrate (thickness 5 mm) / YF ₃ film (film) The thickness was 650 nm) / Ge film (thickness 130 nm) / MgF ₂ film (thickness 200 nm).

FIG. 5 is a diagram showing the wavelength dependence of the transmittance in the optical component of Example 1. FIG. As can be seen from FIG. 5, the optical component of Example 1 was able to achieve a transmittance of 97.2% at a laser wavelength of 9.3 μm. This is sufficient optical performance as a protective window for a laser beam machine that desirably has a transmittance of 97% or more.

[Example 2]
As an optical component, an MgF ₂ film, a Ge film, and a DLC film are formed in this order from the Ge substrate side on one surface of the Ge substrate (the surface that is the laser light emission surface), and the MgF ₂ film and the Ge film are exposed. The anti-reflection film (the YF ₃ film (film thickness 650 nm from the Ge substrate side) / Ge film (film thickness 130 nm) / A protective window for a laser beam machine on which an MgF ₂ film (thickness: 200 nm) was formed was produced. As the Ge substrate, a disk having a diameter of 90 mm and a thickness of 5 mm was used. The MgF ₂ film and the Ge film constituting the multilayer film were formed by a vacuum deposition method, and the DLC film constituting the multilayer film was formed by a sputtering method using a mask having a predetermined opening. Moreover, the transmittance of the produced optical component was evaluated using a Fourier transform infrared spectrophotometer.
The configuration of the optical component produced in Example 2 is as follows: DLC film (film thickness 500 mm) / Ge film (film thickness 80 nm) / MgF ₂ film (film thickness 500 nm) / Ge substrate (thickness 5 mm) / YF ₃ film (film) The thickness was 650 nm) / Ge film (thickness 130 nm) / MgF ₂ film (thickness 200 nm).

In the optical component of Example 2, a transmittance of 97.2% was realized at a laser wavelength of 9.3 μm. This is sufficient optical performance as a protective window for a laser beam machine that desirably has a transmittance of 97% or more.

Next, “wear test (1) (SEVERE ABRASION compliant with MIL-C-675)” and “corrosion test (immersion in hydrochloric acid solution diluted to 50% for 1 hour)” were performed on the optical components of Examples 1 and 2. did. The results are shown in Table 1. After the abrasion test (1), the case where no peeling of the multilayer film occurred was marked with ◯, and the case where the multilayer film was peeled was marked with x. Moreover, the case where peeling of the multilayer film did not occur after the corrosion test was marked with ◯, and the case where peeling of the multilayer film occurred was marked with x.

As shown in Table 1, in the optical components of Examples 1 and 2, the multilayer film did not peel after the wear test (1), and was excellent in wear resistance. Further, as a result of the corrosion test (1), the multilayer film peeled off in the optical component of Example 1, whereas the multilayer film did not peel off in the optical component of Example 2, and the third multilayer film was not peeled off. The lifetime of the optical component in a corrosive environment could be improved by covering the first layer of MgF ₂ film and the second layer of GeF film without exposing the first layer of DLC film.

[Comparative Example 1]
In Comparative Example 1, optical analysis of an optical component corresponding to Patent Document 1 was performed.
The configuration of the optical component of Comparative Example 1 is as follows: DLC film (film thickness 300 nm) / Ge film (film thickness 30 nm) / Y ₂ O ₃ film (film thickness 30 nm) / YF ₃ film (film thickness 600 nm) / Y ₂ O ₃ Film (film thickness 30 nm) / ZnS substrate (thickness 5 mm) / Y ₂ O ₃ film (film thickness 80 nm) / YF ₃ film (1300 nm) / MgF ₂ film (film thickness 400 nm).
FIG. 6 is a diagram illustrating the wavelength dependence of the transmittance when optical analysis is performed on the optical component of Comparative Example 1 using the optical thin film design software Essential Macleod. As can be seen from FIG. 6, the optical component of Comparative Example 1 had a transmittance of 95% or less at a laser wavelength of 9.3 μm. When this optical component is applied as a protective window for a laser beam machine, a thermal lens effect is generated, which causes a problem that the machining accuracy deteriorates during high-speed machining.

[Example 3]
Laser processing machine protection with multilayer films (YF ₃ film (film thickness: 660 nm) / Ge film (film thickness: 120 nm) / DLC film (film thickness: 80 nm)) formed on both sides of the Ge substrate as optical components A window was made. As the Ge substrate, a disk having a diameter of 110 mm and a thickness of 5 mm was used. The MgF ₂ film and Ge film constituting the multilayer film and the antireflection film were formed by vacuum deposition, and the DLC film constituting the multilayer film was formed by plasma CVD. Moreover, the transmittance of the produced optical component was evaluated using a Fourier transform infrared spectrophotometer.
The configuration of the optical component produced in Example 3 is as follows: DLC film (film thickness 80 nm) / Ge film (film thickness 120 nm) / YF ₃ film (film thickness 660 nm) / Ge substrate (thickness 5 mm) / YF ₃ film (film) The thickness was 660 nm) / Ge film (film thickness 120 nm) / DLC film (film thickness 80 nm).

FIG. 7 is a diagram showing the wavelength dependence of the transmittance in the optical component of Example 3. As can be seen from FIG. 7, in the optical component of Example 3, a transmittance of 99.0% was realized at a laser wavelength of 9.3 μm. This is sufficient optical performance as a protective window for a laser beam machine that desirably has a transmittance of 97% or more.

[Example 4]
The configuration of the optical component is as follows: DLC film (film thickness 130 nm) / Ge film (film thickness 110 nm) / YbF ₃ film (film thickness 670 nm) / Ge substrate (thickness 5 mm) / YbF ₃ film (film thickness 670 nm) / Ge film An optical component of Example 4 was fabricated in the same manner as Example 3 except that the film thickness was changed to (film thickness 110 nm) / DLC film (film thickness 130 nm).

FIG. 8 is a diagram showing the wavelength dependence of the transmittance in the optical component of Example 4. FIG. As can be seen from FIG. 8, in the optical component of Example 4, a transmittance of 98.4% was realized at a laser wavelength of 9.3 μm. This is sufficient optical performance as a protective window for a laser beam machine that desirably has a transmittance of 97% or more.

[Example 5]
The configuration of the optical component is DLC film (film thickness 50 nm) / Ge film (film thickness 130 nm) / MgF 2 film (film thickness 640 nm) / Ge substrate (thickness 5 mm) / MgF 2 film (film thickness 640 nm) / Ge film (film) An optical component of Example 5 was fabricated in the same manner as Example 3 except that the thickness was changed to 130 nm) / DLC film (film thickness 50 nm).

FIG. 9 is a diagram showing the wavelength dependence of the transmittance in the optical component of Example 5. As can be seen from FIG. 9, in the optical component of Example 5, a transmittance of 99.3% was realized at a laser wavelength of 9.3 μm. This is sufficient optical performance as a protective window for a laser beam machine that desirably has a transmittance of 97% or more.

[Example 6]
As an optical component, a multilayer film (from the Ge substrate side: YF ₃ film (film thickness: 700 nm) / Ge film (film thickness: 110 nm) / DLC film (film thickness) is formed on one surface of the Ge substrate (the surface to be a laser beam emission surface). 300 nm)) and an antireflection film (YF ₃ film (thickness: 750 nm) from the Ge substrate side / Ge film (thickness: 150 nm) / MgF ₂ film (from the Ge substrate side) A protective window for a laser beam machine having a thickness of 200 nm)) was produced. As the Ge substrate, a disc having a diameter of 110 mm and a thickness of 5 mm was used. The YF ₃ film and Ge film constituting the multilayer film and the antireflection film were formed by vacuum deposition, and the DLC film constituting the multilayer film was formed by plasma CVD. Moreover, the transmittance of the produced optical component was evaluated using a Fourier transform infrared spectrophotometer.
The configuration of the optical component produced in Example 6 is as follows: DLC film (film thickness 300 nm) / Ge film (film thickness 110 nm) / YF ₃ film (film thickness 700 nm) / Ge substrate (thickness 5 mm) / YF ₃ film (film) The thickness was 750 nm) / Ge film (thickness 150 nm) / MgF ₂ film (thickness 200 nm).

FIG. 10 is a diagram showing the wavelength dependence of the transmittance in the optical component of Example 6. As can be seen from FIG. 10, in the optical component of Example 6, a transmittance of 98.4% was realized at the laser wavelength of 10.6 μm. This is sufficient optical performance as a protective window for a laser beam machine that desirably has a transmittance of 97% or more.

[Example 7]
The configuration of the optical component is as follows: DLC film (film thickness 50 nm) / Ge film (film thickness 110 nm) / YbF ₃ film (film thickness 950 nm) / Ge substrate (thickness 5 mm) / YF ₃ film (film thickness 750 nm) / Ge film An optical component of Example 7 was produced in the same manner as Example 6 except that the thickness was changed to (film thickness 150 nm) / MgF ₂ film (film thickness 200 nm).

FIG. 11 is a diagram showing the wavelength dependence of the transmittance in the optical component of Example 7. As can be seen from FIG. 11, in the optical component of Example 7, a transmittance of 98.2% was realized at the laser wavelength of 10.6 μm. This is sufficient optical performance as a protective window for a laser beam machine that desirably has a transmittance of 97% or more.

[Example 8]
The configuration of the optical component is as follows: DLC film (thickness 170 nm) / Ge film (thickness 150 nm) / MgF ₂ film (thickness 600 nm) / Ge substrate (thickness 5 mm) / YF ₃ film (thickness 750 nm) / Ge film An optical component of Example 8 was produced in the same manner as Example 6 except that the film thickness was changed to (film thickness 150 nm) / MgF ₂ film (film thickness 200 nm).

FIG. 12 is a diagram showing the wavelength dependence of the transmittance in the optical component of Example 8. As can be seen from FIG. 12, in the optical component of Example 8, a transmittance of 98.3% was realized at the laser wavelength of 10.6 μm. This is sufficient optical performance as a protective window for a laser beam machine that desirably has a transmittance of 97% or more.

Next, for the optical components of Example 1 and Examples 3 to 8, “Wear test (1) (MIL-C-675 compliant SEVER ABRASION)” and “Wear test (2) (50 kg of sand eraser with a load of 3 kg) Round trip) ”. The results are shown in Table 2. After each abrasion test, the case where no peeling of the multilayer film occurred was marked with ◯, and the case where the multilayer film was peeled was marked with x.

As shown in Table 2, in the optical parts of Example 1 and Examples 3 to 7, peeling of the multilayer film did not occur after the wear test (1). In the optical component of Example 1, the multilayer film peeled after the wear test (2), whereas in the optical components of Examples 3 to 7, the multilayer film did not peel after the wear test (2). The wear resistance could be further improved by adjusting the film thicknesses of the fluoride film, Ge film and DLC film constituting the multilayer film.

This international application claims priority based on Japanese Patent Application No. 2016-096876 filed on May 13, 2016, and the entire contents of this Japanese patent application are incorporated herein by reference. To do.

10 Ge substrate, 11 fluoride film, 12 Ge film, 13 DLC film, 14 multilayer film, 15 antireflection film, 20 multilayer film, 30 laser oscillator, 31 laser light, 32 condenser lens, 33 workpiece, 34 protection window.

Claims (5)

1. An optical component comprising a fluoride film, a Ge film, and a diamond-like carbon film (DLC film) laminated in this order on at least one surface of a Ge substrate from the Ge substrate side.
2. The optical component according to claim 1, wherein the fluoride film is made of at least one selected from the group consisting of YF ₃ , YbF _3, and MgF ₂ .
3. 3. The optical component according to claim 1, wherein the fluoride film and the Ge film are covered with the diamond-like carbon film without being exposed.
4. The film thickness of the fluoride film is 500 nm to 950 nm, the film thickness of the Ge film is 50 nm to 150 nm, and the film thickness of the DLC film is 50 nm to 300 nm. The optical component as described in any one.
5. A laser processing machine comprising the optical component according to any one of claims 1 to 4.

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