JP6625207B2 - Optical parts and laser processing machines - Google Patents

Description

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

CO ₂ lasers oscillating at wavelengths of 9 μm to 11 μm can be used for drilling holes in printed wiring boards built into electronic devices such as smartphones because of their high output oscillation and high absorptivity in resin. Used.

In laser processing machines for drilling, since the condenser lens is installed above the processing area, there is a problem that dirt adheres to the condenser lens due to resin vapor, resin spatter, copper spatter, etc. generated during processing. is there. Conventionally, in order to prevent this, an optical component called a protective window (protective window) is arranged between the condenser lens and the workpiece to prevent damage and deterioration of the condenser lens. The main performance required for the protective window is to have high transparency to a CO ₂ laser, which is infrared light, and to have abrasion resistance to withstand wiping of attached dust and spatter.

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

  In Patent Document 1, it is said that an infrared transmitting structure having excellent impact resistance and durability, and excellent peeling resistance and transmittance as compared with the conventional infrared transmitting structure has been realized.

JP 2008-268277 A

  However, the infrared transmitting structure proposed in Patent Document 1 has good wear resistance because the diamond-like carbon layer is formed on the outermost layer, but has sufficient optical properties when used as an optical component of a laser processing machine. There was a problem that performance could not be obtained. When performing laser processing with a laser processing machine equipped with such an optical component, the optical component absorbs infrared light, causing a temperature distribution to occur on the ZnS substrate, resulting in a laser transmission accuracy called the thermal lens effect. Is reduced. In particular, in a laser processing machine for drilling with an optical component mounted as a protective window, the optical component absorbs infrared light, causing a thermal lens effect, making it impossible to achieve the desired hole position and hole shape processing. However, there is a problem that non-standard defective products are generated. In laser drilling machines for drilling, in order to prevent such problems, the laser processing speed is limited to achieve the required processing accuracy.However, due to the limitation of the processing speed, productivity is reduced. I will.

The present invention has been made to solve the above problems, and has as its object to provide an optical component having a high transmittance to a CO ₂ laser beam and having excellent 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 at the time of high-speed processing.

FIG. 2 is a schematic cross-sectional view illustrating a configuration of the optical component according to the first embodiment. FIG. 3 is a schematic cross-sectional view illustrating another configuration of the optical component according to the first embodiment. FIG. 9 is a schematic cross-sectional view illustrating a configuration of an optical component according to a second embodiment. FIG. 9 is a schematic diagram illustrating a configuration of a laser processing machine according to a third embodiment. FIG. 4 is a diagram illustrating the wavelength dependence of the transmittance of the optical component of the first embodiment. FIG. 9 is a diagram illustrating the wavelength dependence of the transmittance of the optical component of Comparative Example 1. FIG. 9 is a diagram illustrating the wavelength dependence of the transmittance of the optical component according to the third embodiment. FIG. 14 is a diagram illustrating the wavelength dependence of the transmittance of the optical component according to the fourth embodiment. FIG. 14 is a diagram illustrating the wavelength dependence of the transmittance of the optical component of the fifth embodiment. FIG. 14 is a diagram illustrating the wavelength dependence of the transmittance of the optical component according to the sixth embodiment. FIG. 14 is a diagram illustrating the wavelength dependence of the transmittance of the optical component according to the seventh embodiment. FIG. 14 is a diagram illustrating the wavelength dependence of the transmittance of the optical component of the eighth embodiment.

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 assumed that.

  FIG. 1 is a schematic sectional view showing a configuration of the optical component according to the first embodiment. As shown in FIG. 1, the optical component includes a fluoride film 11 laminated on a Ge substrate 10, a Ge film 12 laminated on the fluoride film 11, and a DLC film laminated on the Ge film 12. 13 is provided on both sides of the Ge substrate 10. FIG. 2 is a schematic cross-sectional view illustrating another configuration of the optical component according to the first embodiment. As shown in FIG. 2, the optical component includes a fluoride film 11 laminated on a Ge substrate 10, a Ge film 12 laminated on the fluoride film 11, and a DLC film laminated 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 Literature 1, ZnS is used as a substrate. However, when ZnS having low thermal conductivity is used as a substrate, a 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, and therefore ZnS is not suitable as a substrate of an optical component for a laser processing machine.
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 the optical performance and the mechanical characteristics are not affected. Further, the shape of the Ge substrate 10 is not limited, but, for example, a disk having a diameter of 80 mm to 140 mm and a thickness of 2 mm to 10 mm is preferably used as a protection window for a laser processing machine.

The fluoride film 11 laminated on the Ge substrate 10 only needs to contain at least one of fluorides such as, for example, YF ₃ , YbF ₃ , MgF ₂ , BaF ₂ , and CaF ₂ . From the viewpoint of excellent transparency, it is preferable that the material be at least one selected from the group consisting of YF ₃ , YbF ₃ and MgF ₂ .

  Since the tensile stress increases as the thickness of the fluoride film 11 increases, if the thickness is too large, the film may be damaged, for example, cracks may occur during the formation of the fluoride film 11, and the adhesion of the film may be secured. Can be difficult to do. On the other hand, if the thickness of the fluoride film 11 is too small, it is difficult to obtain the antireflection effect, and the transmittance of infrared light may be reduced. The thickness of the fluoride film 11 is preferably in the range of 500 nm to 950 nm from the viewpoint of realizing high transmittance to infrared light while maintaining the adhesion of the film.

  Since the Ge film 12 laminated on the fluoride film 11 has good adhesion to the DLC film 13, the provision of the Ge film 12 can ensure the adhesion of the DLC film 13. By arranging the Ge film 12 between the DLC film 13 having a compressive stress and the fluoride film 11 having a tensile stress, the balance of the stress in the entire multilayer film 14 is maintained, and the interface, which is an interface having a weak adhesive force, is maintained. A load is prevented between the oxide 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 is difficult to keep the stress balance 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 is likely to occur. On the other hand, if the thickness of the Ge film 12 is too small, it is difficult to obtain the antireflection effect, and the transmittance of infrared light may be reduced. The thickness of the Ge film 12 is preferably from 50 nm to 150 nm, and more preferably from 100 nm to 130 nm, from the viewpoint of realizing high transmittance to infrared light while ensuring adhesion of the film. 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 a high hardness and the adhesion of spatter to diamond-like carbon is weak, it is possible to clean the optical member and easily remove spatter without worrying about the occurrence of scratches. In addition, the optical components can be easily reproduced and reused.

  If the 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 DLC film 13 may not be able to exhibit its original wear resistance due to the influence of the underlayer of the DLC film 13 during wear. Considering these points, the 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-described films may be doped with another element, or a thin film other than the above-described films may be formed.

The anti-reflection film 15 is not limited, 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 film thickness of 50 nm to 800 nm from the Ge substrate 10 side. MgF ₂ film having a are those which are laminated in this order. By providing such an anti-reflection film 15 on one surface of the Ge substrate 10 that becomes the incident surface of the laser beam, the wavelength is 9.3 μm or longer than when the multilayer film 14 is provided on both surfaces of the Ge substrate 10. The transmittance at 10.6 μm can be improved.

  The method of forming the multilayer film 14 and the antireflection film 15 in the optical component of the present invention is not limited as long as the method can form a film on the Ge substrate 10. Examples of generally known film forming methods include a physical vapor deposition method (PVD method) such as a vacuum vapor deposition method and a sputtering method, and a chemical vapor deposition method (CVD method) such as a plasma CVD method. In the present invention, it is preferable to form the fluoride film 11, the Ge film 12, and the antireflection film 15 by a vacuum evaporation method from the viewpoint of excellent production efficiency when film formation is performed using a plurality of materials. Further, in the present invention, it is preferable to form the DLC film 13 by a plasma CVD method from the viewpoint that the composition and thickness of the film can be adjusted with high accuracy.

According to the first embodiment, it is possible to provide an optical component having a high transmittance for CO ₂ laser light having a wavelength of 9 μm to 11 μm and having excellent 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 stacked 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. And covered with a DLC film.

  FIG. 3 is a schematic cross-sectional view illustrating the configuration of the optical component according to the second embodiment. As shown in FIG. 3, the optical component has a fluoride film 11 laminated on a Ge substrate 10, a Ge film 12 laminated on the fluoride film 11, and the fluoride film 11 and the Ge film 12 are exposed. A multilayer film 20 including a fluoride film 11 and a DLC film 13 covering the Ge film 12 is provided on one surface of the Ge substrate 10 so that the anti-reflection film 15 described in the first embodiment is replaced with the Ge substrate. 10 are 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, the description thereof is omitted.

  The 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 thickness of the DLC film 13 formed on the side surface of the fluoride film 11 and the side surface of the Ge film 12 so that the fluoride film 11 and the Ge film 12 are not exposed is a film in which the fluoride film 11 and the Ge film 12 are not exposed. Any thickness is acceptable. Such a DLC film 13 can be formed by adjusting the size of the opening of the mask when forming the film by the sputtering method 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 to gas generated during processing.

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

Embodiment 3 FIG.
The laser beam machine according to the third embodiment includes the optical component according to the first or second embodiment.

  FIG. 4 is a schematic diagram illustrating a configuration of a laser processing machine according to the third embodiment. As shown in FIG. 4, the laser processing machine includes a laser oscillator 30, a condenser lens 32 for condensing laser light 31 emitted from the laser oscillator 30, and a processing target such as the condenser lens 32 and a printed wiring board. And a protection window 34 disposed in the optical path of the laser light 31 between the object 33 and the object 33. The optical component according to the first or second embodiment is used as the protection window 34. Here, the protection window 34 is installed such 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). The configuration of the laser processing machine shown in FIG. 4 is an example, and is not limited to this configuration as long as the configuration includes a laser oscillator and an optical system.

  In the laser beam machine configured as described above, the laser beam 31 emitted from the laser oscillator 30 is condensed by the condensing lens 32, passes through the protection window 34, and then irradiates the workpiece 33 to form a hole. Becomes possible.

Since the optical component according to the first or second embodiment has a high transmittance to CO ₂ laser light, by using it as the protective window 34, the thermal lens effect caused by laser absorption can be prevented, and processing can be performed. A laser processing machine capable of high-speed processing without causing a decrease in accuracy can be realized. Further, 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 side, the protective window 34 can be used for a long period of time without worrying about the occurrence of scratches. Dust and spatter adhering to the surface can be easily removed. Generally, since the protection window 34 can be separated from the workpiece 33 by only about 100 mm, the protection 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, by using this as the protective window 34, it is possible to extend the life of the optical component of the laser beam machine.

  According to the third embodiment, it is possible to provide a laser processing machine that can perform high-speed processing without lowering processing accuracy while improving maintainability.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Examples 1 and 2 are reference examples.

[Example 1]
As an optical component, a multilayer film (a MgF ₂ film (thickness: 500 nm) / Ge film (thickness: 80 nm) / Ge film (thickness: 80 nm) / DLC film (thickness: from the Ge substrate side) is formed on one surface of the Ge substrate (surface serving as a laser light emission surface). 500 nm), and an anti-reflection film (YF ₃ film (650 nm film thickness) / Ge film (130 nm film thickness) / MgF ₂ film (from the Ge substrate side) is formed on the other surface (the surface serving as the laser light incident surface). A protective window for a laser processing machine having a thickness of 200 nm) was formed. As a Ge substrate, a disk having a diameter of 90 mm and a thickness of 5 mm was used. The MgF ₂ film, the Ge film, and the antireflection 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. The transmittance of the manufactured optical component was evaluated using a Fourier transform infrared spectrophotometer.
The configuration of the optical component manufactured in Example 1 is a DLC film (500 nm thick) / Ge film (80 nm thick) / MgF ₂ film (500 nm thick) / Ge substrate (5 mm thick) / YF ₃ film (film Thickness: 650 nm) / Ge film (thickness: 130 nm) / MgF ₂ film (thickness: 200 nm).

  FIG. 5 is a diagram illustrating the wavelength dependence of the transmittance of the optical component according to the first embodiment. As can be seen from FIG. 5, the optical component of Example 1 could achieve a transmittance of 97.2% at a laser wavelength of 9.3 μm. This is a sufficient optical performance as a protective window for a laser beam machine desirably having a transmittance of 97% or more.

[Example 2]
As an optical component, a MgF ₂ film, a Ge film, and a DLC film are formed in this order on one surface of the Ge substrate (a surface serving as a laser light emission surface) from the Ge substrate side, and the MgF ₂ film and the Ge film are exposed. And the other surface (the surface that becomes the laser light incident surface) is coated with an antireflection film (YF ₃ film (650 nm thick) from the Ge substrate side) / Ge film (130 nm thick) / A protection window for a laser processing machine on which an MgF ₂ film (thickness: 200 nm) was formed was produced. As a 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. The transmittance of the manufactured optical component was evaluated using a Fourier transform infrared spectrophotometer.
The configuration of the optical component manufactured in Example 2 was a DLC film (thickness: 500 mm) / Ge film (thickness: 80 nm) / MgF ₂ film (thickness: 500 nm) / Ge substrate (thickness: 5 mm) / YF ₃ film (film) Thickness: 650 nm) / Ge film (thickness: 130 nm) / MgF ₂ film (thickness: 200 nm).

  The optical component of Example 2 was able to realize a transmittance of 97.2% at a laser wavelength of 9.3 μm. This is a sufficient optical performance as a protective window for a laser beam machine desirably having a transmittance of 97% or more.

  Next, the optical components of Examples 1 and 2 were subjected to "wear test (1) (SAVERE ABRATION according to MIL-C-675)" and "corrosion test (immersion in hydrochloric acid aqueous solution diluted to 50% for 1 hour)". did. Table 1 shows the results. After the abrasion test (1), ○ indicates that the multilayer film did not peel off, and X indicates that the multilayer film peeled off. Moreover, when the peeling of the multilayer film did not occur after the corrosion test, it was evaluated as ○, and when the peeling of the multilayer film occurred, it was evaluated as ×.

As shown in Table 1, in the optical components of Examples 1 and 2, the multilayer film did not peel off after the wear test (1), and was excellent in wear resistance. As a result of the corrosion test, the optical component of Example 1, while the separation of the multilayer film occurs, the optical components of the second embodiment, the multilayer film is not peeled off, the third layer of the multilayer film By covering the first layer MgF2 film and the second layer Ge film without exposing the DLC film, the life of the optical component in a corrosive environment could be improved.

[Comparative Example 1]
In Comparative Example 1, an optical analysis of an optical component corresponding to Patent Document 1 was performed.
The configuration of the optical component of Comparative Example 1 was DLC film (thickness 300 nm) / Ge film (thickness 30 nm) / Y ₂ O ₃ film (thickness 30 nm) / YF ₃ film (thickness 600 nm) / Y ₂ O ₃ and a membrane (thickness 30 nm) / ZnS substrate (thickness 5mm) / Y ₂ O ₃ film (thickness 80 nm) / YF ₃ film (1300 nm) / MgF ₂ film (thickness 400 nm).
FIG. 6 is a diagram illustrating the wavelength dependence of the transmittance when the optical component of Comparative Example 1 is subjected to optical analysis using the optical thin film design software Essential Macloid. As can be seen from FIG. 6, the optical component of Comparative Example 1 had a transmittance of 95% or less at the 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 processing accuracy is deteriorated during high-speed processing.

[Example 3]
As an optical component, on both surfaces of the Ge substrate, a protective multilayer film (Ge YF ₃ film (thickness 660nm from the substrate side) / Ge film (thickness 120 nm) / DLC layer (thickness 80 nm)) Laser processing machine to form a A window was made. A disk having a diameter of 110 mm and a thickness of 5 mm was used as the Ge substrate. The YF ₃ 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 plasma CVD method. The transmittance of the manufactured optical component was evaluated using a Fourier transform infrared spectrophotometer.
The configuration of the optical component prepared in Example 3, DLC film (film thickness 80 nm) / Ge film (thickness 120 nm) / YF ₃ film (thickness 660 nm) / Ge substrate (thickness 5 mm) / YF ₃ film (film Thickness: 660 nm) / Ge film (film thickness: 120 nm) / DLC film (film thickness: 80 nm).

  FIG. 7 is a diagram illustrating the wavelength dependence of the transmittance of the optical component according to the third embodiment. As can be seen from FIG. 7, the optical component of Example 3 could achieve a transmittance of 99.0% at a laser wavelength of 9.3 μm. This is a sufficient optical performance as a protective window for a laser beam machine desirably having a transmittance of 97% or more.

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

  FIG. 8 is a diagram illustrating the wavelength dependence of the transmittance of the optical component according to the fourth embodiment. As can be seen from FIG. 8, the optical component of Example 4 was able to realize a transmittance of 98.4% at a laser wavelength of 9.3 μm. This is a sufficient optical performance as a protective window for a laser beam machine desirably having a transmittance of 97% or more.

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

  FIG. 9 is a diagram illustrating the wavelength dependence of the transmittance of the optical component according to the fifth embodiment. As can be seen from FIG. 9, the optical component of Example 5 could achieve a transmittance of 99.3% at a laser wavelength of 9.3 μm. This is a sufficient optical performance as a protective window for a laser beam machine desirably having a transmittance of 97% or more.

[Example 6]
As an optical component, a multilayer film (a YF ₃ film (thickness: 700 nm) / Ge film (thickness: 110 nm) / Ge film (thickness: 110 nm) / DLC film (thickness: 300 nm), and an antireflection film (YF ₃ film (750 nm thick) / Ge film (150 nm thick) / MgF ₂ film (150 nm thick from the Ge substrate side) is formed on the other surface (the surface that becomes the laser light incident surface). A protective window for a laser processing machine having a thickness of 200 nm) was formed. A disk having a diameter of 110 mm and a thickness of 5 mm was used as the Ge substrate. The YF ₃ film, the Ge film, and the antireflection film constituting the multilayer film were formed by a vacuum deposition method, and the DLC film constituting the multilayer film was formed by a plasma CVD method. The transmittance of the manufactured optical component was evaluated using a Fourier transform infrared spectrophotometer.
The configuration of the optical component prepared in Example 6, DLC film (film thickness 300 nm) / Ge film (thickness 110 nm) / YF ₃ film (thickness 700 nm) / Ge substrate (thickness 5 mm) / YF ₃ film (film Thickness: 750 nm) / Ge film (150 nm thickness) / MgF ₂ film (200 nm thickness).

  FIG. 10 is a diagram illustrating the wavelength dependence of the transmittance of the optical component according to the sixth embodiment. As can be seen from FIG. 10, the optical component of Example 6 could achieve a transmittance of 98.4% at a laser wavelength of 10.6 μm. This is a sufficient optical performance as a protective window for a laser beam machine desirably having a transmittance of 97% or more.

[Example 7]
The configuration of the optical component is a DLC film (50 nm thick) / Ge film (110 nm thick) / YbF ₃ film (950 nm thick) / Ge substrate (5 mm thick) / YF ₃ film (750 nm thick) / Ge film An optical component of Example 7 was produced in the same manner as in 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 illustrating the wavelength dependence of the transmittance of the optical component according to the seventh embodiment. As can be seen from FIG. 11, the optical component of Example 7 could achieve a transmittance of 98.2% at a laser wavelength of 10.6 μm. This is a sufficient optical performance as a protective window for a laser beam machine desirably having a transmittance of 97% or more.

Example 8
The configuration of the optical component is as follows: DLC film (film thickness 170 nm) / Ge film (film thickness 150 nm) / MgF ₂ film (film thickness 600 nm) / Ge substrate (5 mm thickness) / YF ₃ film (film thickness 750 nm) / Ge film An optical component of Example 8 was produced in the same manner as in 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 illustrating the wavelength dependence of the transmittance of the optical component according to the eighth embodiment. As can be seen from FIG. 12, the optical component of Example 8 could achieve a transmittance of 98.3% at a laser wavelength of 10.6 μm. This is a sufficient optical performance as a protective window for a laser beam machine desirably having a transmittance of 97% or more.

  Next, with respect to the optical components of Example 1 and Examples 3 to 8, “wear test (1) (SAVERE ABRASION according to MIL-C-675)” and “wear test (2) (50 sand erasers with a load of 3 kg) were used. Round trip) "was carried out. Table 2 shows the results. After each abrasion test, the case where the peeling of the multilayer film did not occur was evaluated as ○, and the case where the peeling of the multilayer film occurred was evaluated as x.

As shown in Table 2, in the optical components of Example 1 and Examples 3 to 8 , peeling of the multilayer film did not occur after the wear test (1). In the optical component of Example 1, the multilayer film was peeled off after the wear test (2), whereas in the optical components of Examples 3 to 8 , the multilayer film was not peeled off after the wear test (2). By adjusting the thickness of the fluoride film, the Ge film, and the DLC film constituting the multilayer film, the wear resistance could be further improved.

  This international application claims priority based on Japanese Patent Application No. 2016-096876 filed on May 13, 2016, and incorporates the entire contents of this Japanese patent application into this international application. I 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 beam, 32 condenser lens, 33 workpiece, 34 protection window.

Claims (4)

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 the Ge substrate from the Ge substrate side, and the thickness of the fluoride film is 500 nm to 950 nm. An optical component , wherein the thickness of the film is 50 nm to 150 nm, and the thickness of the DLC film is 50 nm to 300 nm . Optical component according to claim 1 wherein the fluoride film, characterized by comprising at least one selected from the group consisting of YF _3, YbF ₃ and MgF _2.   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. Laser processing machine, characterized in that it comprises an optical component according to any one of claims 1-3.

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