Reflection plate

Abstract

A reflection plate (100) comprises: a mirror layer (110) provided with a first surface (111) that reflects light; and a fiber layer (120) disposed on a second surface (112) of the mirror layer (110), the second surface (112) being opposite the first surface (111).

Description

Reflector

[0001] The present invention relates to a reflector.

[0002] There is known a reflector that scans reflected light by swinging a mirror surface. Japanese Patent Application Laid-Open Publication No. 2010-2776 (JP2010-2776A) discloses a micromirror device in which a diamond-like carbon film is formed on a mirror.

[0003] As described above, since the reflector swings, weight reduction is desired.

[0004] The present disclosure has been made in consideration of such points and aims to reduce the weight of the reflector.

[0005] The reflector of the present disclosure includes a mirror layer having a first surface that reflects light, and a fiber layer disposed on a second surface opposite to the first surface of the mirror layer.

[0006] In the reflector of the present disclosure, in the fiber layer, the fibers may be substantially oriented in the plane direction.

[0007] In the reflector of the present disclosure, a porous layer may be disposed on a second surface opposite to a first surface of the fiber layer to which the mirror layer is joined.

[0008] In the reflector of the present disclosure, the fiber layer and the porous layer may be alternately laminated on the second surface side of the mirror layer. [[ID=2x6]]

[0009] In the reflector of the present disclosure, the fiber layer may contain carbon fibers.

[0010] The reflector of the present disclosure includes a mirror layer having a first surface that reflects light, and a porous layer disposed on a second surface opposite to the first surface of the mirror layer.

[0011] The reflector of the present disclosure includes a mirror layer having a first surface that reflects light, and a composite layer disposed on a second surface opposite to the first surface of the mirror layer and including fibers and a porous body.

[0012] In the reflector of this disclosure, the thermal conductivity in the planar direction of the fiber layer may be 10 W / m·K or more and 800 W / m·K or less.

[0013] In the reflector according to this disclosure, the space factor of the fiber layer may be 2% or more and 60% or less.

[0014] In the reflector of this disclosure, the average aspect ratio of the fibers in the fiber layer may be 5 or more and 1000 or less.

[0015] In the reflector according to this disclosure, the thickness of the fiber layer may be 300 μm or more and 3000 μm or less.

[0016] This is a schematic diagram of the laser processing machine. This is a front view of the reflector according to the first embodiment. This is a cross-sectional view of the reflector according to the first embodiment. This is a cross-sectional view of the reflector according to the second embodiment. This is a cross-sectional view of the reflector according to a modified example. This is a cross-sectional view of the reflector according to the third embodiment. This is a cross-sectional view of the reflector according to the fourth embodiment.

[0017] (First Embodiment) Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a schematic diagram of a laser processing machine using a galvanometer mirror according to this embodiment. The laser processing machine 1 mainly comprises a laser oscillator 2, two galvanometer scanners 3A and 3B, and an fθ lens 4. The galvanometer scanners 3A and 3B are each equipped with a galvanometer mirror 30A and 30B.

[0018] In the laser processing machine 1, the laser oscillator 2 emits laser light toward the galvanometer mirror 30A. The galvanometer scanner 3A oscillates the galvanometer mirror 30A, causing the laser light reflected by the galvanometer mirror 30A to irradiate the galvanometer mirror 30B.

[0019] The galvanometer scanner 3B oscillates the galvanometer mirror 30B to direct the laser beam toward the fθ lens 4. The laser beam incident on the fθ lens 4 is focused on the workpiece, and processing such as cutting is performed on the workpiece.

[0020] Figure 2 is a front view of the reflector 100 used as galvanometer mirrors 30A and 30B. Figure 3 is a cross-sectional view taken along line A-A in Figure 2. The reflector 100 reflects light rays such as laser light. The cross-sectional view shown in Figure 1 is a cross-sectional view of the reflector 100 taken along a direction perpendicular to the first surface 101 that reflects light rays. Hereinafter, the direction parallel to the first surface 101 will be referred to as the surface direction x, and the direction perpendicular to the surface direction will be referred to as the stacking direction z.

[0021] In the reflector 100, a mirror layer 110 and a fiber layer 120 are stacked in this order along the stacking direction z. The mirror layer 110 reflects light rays such as laser light on its first surface 111. The fiber layer 120 is arranged on the second surface 112 of the mirror layer 110, which is located on the opposite side of the first surface 111. The mirror layer 110 is made of gold, silver, aluminum, silicon carbide (SiC), silicon (Si), or various glass materials. The thickness of the mirror layer 110 in the stacking direction is preferably 1 μm to 100 μm. The thickness of the fiber layer 120 in the stacking direction is preferably 10 μm to 1000 μm, preferably 10 μm to 500 μm, preferably 30 μm to 300 μm, preferably 40 μm to 250 μm, and preferably 50 μm to 200 μm. By having the thickness of the fiber layer 120 in the lamination direction within the above range, it is possible to achieve both weight reduction, miniaturization, and thermal diffusion of the reflector 100. Furthermore, the thickness of the reflector 100 in the lamination direction is preferably 10 μm to 5000 μm, preferably 10 μm to 3000 μm, preferably 450 μm to 2000 μm, and preferably 650 μm to 1350 μm. By having the thickness of the reflector 100 in the lamination direction within the above range, it is possible to achieve both weight reduction, thermal diffusion, and high strength of the reflector 100.

[0022] The fiber layer 120 is formed from fibers. The fiber material is preferably an inorganic material, such as metal, ceramics, or carbon materials (carbon fiber, carbon nanotubes, diamond, graphite, etc.), and may contain two or more of these. From the viewpoint of lightness, the inorganic material is preferably a carbon material. The fiber layer 120 may be formed, for example, from a fiber sheet in which fibers are processed into layers. By using a fiber sheet, both weight reduction and strength of the reflector 100 can be achieved. Examples of fiber sheets include nonwoven fiber fabrics, woven fiber fabrics, and fiber meshes.

[0023] The above metals are not particularly limited, but examples include copper, aluminum, stainless steel, nickel, titanium, magnesium, iron, and cobalt.

[0024] The ceramics mentioned above are not particularly limited, but include oxide ceramics containing elements such as aluminum, boron, silicon, and magnesium, and non-oxidizing ceramics (nitride ceramics, carbide ceramics, and phosphorylated ceramics). Examples of oxide ceramics include aluminum oxide and magnesium oxide, examples of nitride ceramics include aluminum nitride, magnesium nitride, and boron nitride, and examples of carbide ceramics include silicon carbide.

[0025] There are no particular limitations on the method for manufacturing the fiber sheet, but examples include a compression molding method of a web made of fibers and a wet papermaking method, with the wet papermaking method being preferred from the viewpoint of fiber orientation. When obtaining a fiber sheet by compression molding a web made of fibers, a method of compression molding of a web obtained by the carding method, airlaid method, etc., is used. At this time, there are no particular limitations on the direction in which the fibers extend, but it is preferable that they extend in a direction substantially parallel to the reflective surface (first surface 101), so that the heat generated in the mirror layer 110 when light rays are irradiated onto the reflective surface can be uniformly diffused in the surface direction, and as a result, both weight reduction of the reflector and prevention of deformation due to heat localization can be achieved. To strengthen the bonding between the fibers, the fiber sheet may be impregnated with a binder, or to improve strength, the fiber sheet may be filled with a binder. There are no particular limitations on the binder, but for example, in addition to organic materials such as acrylic resin, epoxy resin, urethane resin, and styrene resin, inorganic materials such as colloidal silica, water glass, and sodium silicate can be used. Alternatively, a heat-adhesive resin may be pre-coated onto the surface of the fibers, and after laminating a web made of fibers, it may be subjected to pressure and heat compression to obtain a fiber sheet.

[0026] Alternatively, a fiber sheet can be obtained by preparing an aqueous solution in which fibers are dispersed and then forming it using a wet papermaking method. In this case, dispersants, thickeners, defoamers, flocculants, fixing agents, etc., can be added as appropriate in addition to the fibers. The obtained fiber sheet may also be sintered to bond the fibers together, or it may be pressure-molded.

[0027] Furthermore, in the fiber layer 120, the average fiber diameter can be set arbitrarily, but is preferably 0.1 μm or more and 100 μm or less, and may be 0.1 μm or more and 50 μm or less, 0.1 μm or more and 30 μm or less, or 0.1 μm or more and 10 μm or less. By having the average fiber diameter within the above range, it is possible to achieve both weight reduction and strength assurance of the reflector 100. In this specification, "average fiber diameter" refers to the average area diameter derived by calculating the cross-sectional area of ​​the fibers (for example, using known software) in a cross-section in the stacking direction within an arbitrary range of the fiber layer 120 imaged with a microscope, and then calculating the diameter of a circle having the same area as said cross-sectional area (for example, the average value of 20 fibers). Here, in this disclosure, for example, the average diameter in a fiber bundle formed by the aggregation of multiple carbon nanotubes (for example, carbon nanotubes with a diameter of 4 nm) can be treated as the average fiber diameter.

[0028] Furthermore, the average fiber length is preferably in the range of 0.01 mm to 10.0 mm, but may also be in the range of 0.05 mm to 10.0 mm, or in the range of 0.1 mm to 5.0 mm. When the average fiber length is within the above range, for example, when the fiber layer 120 of this embodiment is manufactured by papermaking, it is expected that so-called fiber clumps will not easily form, the dispersion will be easily adjusted appropriately, and the effect of strength improvement due to entanglement between fibers will be more easily exhibited, and furthermore, the thermal diffusivity in the direction along the fiber sheet will be improved. As a result, both the lightness and thermal diffusivity of the fiber sheet can be achieved. In this specification, "average fiber length" is the value obtained by measuring the length of, for example, 20 fibers with a microscope and averaging the measured values.

[0029] <Aspect Ratio> Here, the aspect ratio of the fibers used in the fiber layer 120 is preferably 1 or more and 1000 or less, and more preferably 10 or more and 1000 or less. Here, "aspect ratio" in this specification refers to the "ratio of the average fiber length to the average fiber diameter" obtained from fibers imaged with a microscope. Here, the average value is, for example, the average value of 20 fibers. In this case, the aspect ratio of the fiber can be expressed as "aspect ratio = average fiber length / average fiber diameter". That is, for example, in the case of a fiber with an average fiber length of 2.0 mm and an average fiber diameter of 20 μm, the aspect ratio of the particle is 100.

[0030] In the fiber layer 120, the thermal conductivity in the plane direction x is preferably 10 W / m·K or higher, more preferably 15 W / m·K or higher, and even more preferably 50 W / m·K or higher. The thermal conductivity can be measured using steady-state methods (such as the heat flow meter method) or transient methods (such as the laser flash method, temperature wave thermal analysis method, or hot-wire method). For example, the fiber layer 120 can be cut to a predetermined size and measured using a flash method thermal diffusivity measuring device (NETZSCH LFA447 NanoFlash).

[0031] Furthermore, the packing density of the fiber layer 120 is preferably 2% or more and 60% or less, more preferably 2% or more and less than 50%, and preferably 5% or more and 40% or less. By having the packing density of the fiber layer 120 within the above range, both lightness and thermal diffusivity can be achieved.

[0032] The packing density can be determined as an area ratio in a cross-section in the stacking direction within an arbitrary range of the fiber layer 120 using an electron microscope (SEM) and known image analysis software. Specifically, the average value obtained from cross-sectional samples (e.g., 20) of the fiber layer 120 in the SEM image can be used to determine the packing density of the fiber layer 120 using the following formula: Packing density (%) = Area occupied by fibers in the fiber layer 120 / (Area occupied by fibers in the fiber layer 120 + Area occupied by areas other than the fiber layer 120) × 100

[0033] The mirror layer 110 and the fiber layer 120 may be directly joined or joined via a bonding material. The bonding material is not particularly limited, but it is preferable to include resin materials and inorganic materials. As organic materials, silicone resin, fluororesin, acrylic resin, epoxy resin, polyimide resin, polyamide resin, polyester resin, polyolefin resin, or these resin materials mixed with fillers can be used. As inorganic materials, for example, metal oxides such as sodium silicate and potassium silicate can be used. Another example is the use of carbon materials. As carbon materials, sintered resins can be used.

[0034] As described above, the reflector 100 of this embodiment is formed from a mirror layer 110 and a fiber layer 120. This makes it possible to reduce the weight compared to conventional reflectors in which a support made of ceramics or the like is used on the second surface 112 side of the mirror layer 110. This makes it possible to achieve both lightness and oscillating properties for the reflector 100.

[0035] Furthermore, by arranging the fiber layer 120 on the second surface 112 of the mirror layer 110, the mirror layer 110 has excellent heat resistance against heat generated by the laser light irradiated onto it. In addition, the heat generated by the laser light can be diffused in the planar direction. As a result, the heat of the reflector 100 is uniformly heated in the planar direction, reducing the warping of the mirror layer 110 during heating and maintaining its function as a reflector (optical axis control).

[0036] Preferably, each fiber in the fiber layer 120 extends in a substantially planar direction x. By manufacturing it using the wet papermaking method described above, a fiber layer 120 with substantially oriented fibers can be obtained. Even when using the above method to form the fiber layer 120 using a web made of fibers, an oriented fiber layer 120 can be obtained by compression molding using a web in which each fiber is oriented.

[0037] The orientation of each fiber in the fiber layer 120 can be defined by the average degree of orientation. Specifically, it can be calculated by the following method using an SEM. First, an SEM image is obtained of a 500 μm wide cross-section in the stacking direction z (for example, an observation area of ​​500 μm × 500 μm). If the number of fibers in the observation area is less than 20, the observation area may be widened. In the obtained SEM image, a straight line is drawn passing through both ends in the length direction of each fiber, and the angle between the fiber layer 120 and the above straight line is defined as the fiber orientation angle. The orientation angle is calculated for all fibers in the SEM image, and the average value obtained by excluding the maximum and minimum values ​​is defined as the average orientation angle. Note that some fibers may be difficult to identify (for example, bent in a large U-shape), but in this case, they may be excluded from observation within reasonable limits. This average orientation angle is preferably within ±20° of the fiber layer 120, and this is defined as a "approximately oriented" state. The average orientation angle is more preferably within ±15°. When the average orientation angle is within the above range, the thermal conductivity in the plane direction x is improved, and the uniformity of heat within the reflector 100 is improved.

[0038] (Method for manufacturing the fiber layer 120) For example, the following method can be used to manufacture the fiber layer 120. Fibers to be made into the fiber layer 120 are placed in water and a slurry solution is prepared using a stirring mixer. Dispersants, thickeners, defoamers, etc. may be added as appropriate. Next, wet papermaking is performed using this slurry solution in a paper machine. As the paper machine, a cylinder paper machine, a long screen paper machine, a short screen paper machine, an inclined paper machine, or a combination paper machine that combines the same or different types of paper machines from among these can be used. After that, the wet paper that has been made is dewatered and dried using an air dryer. The dried paper is sintered in a nitrogen atmosphere at a temperature below the melting point of the fibers to obtain a fiber layer 120 in which the fibers are joined together. Note that this sintering step may or may not be performed depending on the characteristics of the fiber layer 120. Next, in order to improve homogeneity, the fiber layer 120 is uniformly pressurized (for example, linear pressure of 200 kg / cm) to obtain the fiber layer 120 used in the present invention. The method for manufacturing the fiber layer 120 is not limited to this, and can be appropriately adjusted according to the material of the fibers used, the required thickness of the fiber layer 120, the packing ratio, etc.

[0039] (Method for forming the bonding layer) The method for forming the bonding layer is not particularly limited, but for example, the following method can be used. Sodium siliceous fluoride is added to water glass and then kneaded to make a paste. This paste is uniformly applied to one side of the fiber layer 120 and placed in a constant temperature bath and left to stand for 24 hours to harden the paste. After that, the surface is polished and smoothed to obtain a laminate in which the bonding layer has been formed. Alternatively, a thermosetting resin sheet (for example, 10 μm thick) that softens when heated and then hardens can be used. This resin sheet is bonded to one side of the fiber layer 120 while being heated to the softening temperature of the resin sheet, and a release-treated polyester film is further laminated on the side of the resin sheet opposite to the fiber layer 120 side, with the release-treated surface facing the resin sheet (laminated). After that, this laminate is heated to a predetermined hardening temperature (for example, 180°C) and hardening time (for example, 1 hour) to heat-harden the resin sheet and form a bonding layer. After that, the release-treated polyester film is peeled off. This allows for the creation of a laminate with a bonding layer. In this case, it is preferable that the surface of the bonding layer is smooth.

[0040] (Method for manufacturing the reflector 100) The reflector 100 can be manufactured by forming a mirror layer 110 on the smoothed surface of the bonding layer of a laminate of a fiber layer 120 and a bonding layer using a resistance heating method (vacuum deposition method). Furthermore, the thickness and smoothness of each layer can be adjusted by polishing or other means to the mirror layer 110. Note that the method for forming the mirror layer 110 is not limited to the method described above. Other methods for forming the mirror layer 110 include other vacuum deposition methods (EB method, high-frequency induction heating method), ion plating method, sputtering method, chemical vapor deposition (CVD method), etc.

[0041] (Second Embodiment) Next, the second embodiment will be mainly described in terms of differences from the first embodiment. FIG. 4 is a cross-sectional view of the reflector 200 according to the second embodiment. In the reflector 200 according to the second embodiment, a mirror layer 110, a fiber layer 120, and a porous layer 130 are laminated in this order along the lamination direction. That is, the porous layer 130 is disposed on the second surface 122 side of the fiber layer 120 opposite to the first surface 121 on which the mirror layer 110 is disposed.

[0042] The porous layer 130 contains an inorganic material. The inorganic material is not particularly limited, and examples include metals, ceramics, carbon materials (such as carbon fibers, carbon nanotubes, diamond, graphite, etc.). The occupancy ratio of the porous body in the porous layer 130 is preferably 10% or more and 90% or less, more preferably 15% or more and 85% or less, and even more preferably 20% or more and 80% or less. With such a configuration, the porous layer 130 has greater strength and excellent rigidity compared to the fiber layer 120, and the reflector 200 can achieve both light weight and strength.

[0043] The occupancy ratio of the porous layer 130 can be obtained as an area ratio in a cross-section in the lamination direction in an arbitrary range using an electron microscope (SEM) and known image analysis software, similar to the occupancy ratio of the fiber layer 120 described above.

[0044] The above-mentioned metal is not particularly limited, and examples include copper, aluminum, stainless steel, nickel, titanium, magnesium, iron, and cobalt.

[0045] The above-mentioned ceramics are not particularly limited, and examples include oxide-based ceramics containing elements such as aluminum, boron, silicon, and magnesium, and non-oxide-based ceramics (nitride-based ceramics, carbide-based ceramics, phosphide-based ceramics). Examples of oxide-based ceramics include aluminum oxide and magnesium oxide. Examples of nitride-based ceramics include aluminum nitride, magnesium nitride, and boron nitride. Examples of carbide-based ceramics include silicon carbide.

[0046] The thickness of the porous layer 130 is preferably 50 μm or more and 5000 μm or less, may be 100 μm or more and 5000 μm or less, may be 300 μm or more and 3000 μm or less, or may be 500 μm or more and 2000 μm or less. By the thickness of the porous layer 130 being within the above range, it is possible to achieve both light weight and strength of the reflector 200.

[0047] The thickness of the fiber layer 120 is thinner than the thickness of the porous layer 130. Thereby, it is possible to achieve both light weight and strength of the reflector 200.

[0048] The form of the holes provided in the porous layer 130 is not particularly limited, and may be either open holes or closed holes. These holes may be independent, or may be continuous through-holes in which a plurality of holes are connected, or may be through-holes penetrating the porous layer 130. Further, the porous layer 130 may simultaneously include these.

[0049] The manufacturing method of the porous layer 130 is not particularly limited, and examples include a method using foaming, a method using a sacrificial material, a method of adhering a plurality of particles or short fibers, etc. Specific examples of the method using foaming include a method of manufacturing a foamed metal by a direct foaming method. Specific examples of using a sacrificial material include a method of manufacturing a foamed metal in which a binder is mixed with a metal and the binder is heated and vaporized to form holes. Specific examples of the method of adhering a plurality of particles include a method of manufacturing a foamed metal in which a binder resin solution in which metal particles are dispersed is dried and solidified, and further heated to vaporize the binder resin and sinter between the metal particles to form a space (hole) between the metal particles.

[0050] The average particle diameter of the particles used for the porous layer 130 is preferably 0.05 μm or more and 500 μm or less, more preferably 0.1 μm or more and 100 μm or less, and even more preferably 1 μm or more and 50 μm or less. By the average particle diameter of the particles used for the porous layer 130 being within the above range, the size of the formed holes can be adjusted, and it is possible to achieve both strength and light weight in the porous layer 130. Here, the "average particle diameter" in this specification is the average value of the diameters calculated from the particles imaged by a microscope (for example, the average value of 20 particles).

[0051] <Particles> The particles mentioned above may be particles or short fibers. For example, if the particles are short fibers, the average fiber length (average length of the particles) of the short fibers used in the porous layer 130 is preferably 0.1 μm or more and 100 μm or less, and may be 0.1 μm or more and 50 μm or less. By having the average fiber length of the short fibers used in the porous layer 130 within the above range, the size of the pores formed can be adjusted, making it possible to achieve both strength and lightness in the porous layer 130.

[0052] The fiber layer 120 and the porous layer 130 may be directly joined together, or they may be joined together via a bonding material.

[0053] In the reflector 200 of the second embodiment, a porous layer 130 is provided, which makes it possible to achieve both support and lightness for the mirror layer 110.

[0054] (Method for manufacturing the porous layer 130) The method for manufacturing the porous layer 130 is not particularly limited, but a method of binding multiple inorganic particles together can be used. For example, a resin solution containing aluminum oxide fine particles is stirred to prepare a slurry solution. This slurry solution is applied to one side of a ceramic plate and dried and solidified. Then, the porous layer 130 can be obtained by heating it at a temperature below the melting point of aluminum oxide using an electric furnace or the like to cause volatilization of the resin components and sintering between the aluminum oxide fine particles, and separating it from the ceramic plate.

[0055] (Method for manufacturing the reflector 200 of the second embodiment) The method for manufacturing the reflector 200 of the second embodiment is not particularly limited, but it can be manufactured by providing a porous layer 130 to the reflector 100 of the first embodiment. Sodium siliceous fluoride is added to water glass and kneaded to make a paste. After uniformly applying this paste to one side of the porous layer 130, the side of the reflector 100 opposite to the first side (reflective surface) 101 is brought into close contact with the side to which the paste has been applied. Then, it is left to stand in a constant temperature bath for 24 hours to harden the paste and obtain the reflector 200 of the second embodiment. Alternatively, a thermosetting resin sheet (for example, 10 μm thick) that softens when heated and then hardens can be used. This resin sheet is bonded to one side of the porous layer 130 while being heated to the softening temperature of the resin sheet. Then, the side of the reflector 100 opposite to the first side 101 is laminated onto this resin sheet surface. Then, by heating at a predetermined curing temperature (e.g., 180°C) and curing time (e.g., 1 hour), the reflector of the second embodiment can be obtained.

[0056] In addition, as a modification, the positions of the fiber layer 120 and the porous layer 130 may be swapped, provided that it does not interfere with the function in the second embodiment. Figure 5 is a cross-sectional view of a reflector 210 according to such a modification. The mirror layer 110, the porous layer 130, and the fiber layer 120 are laminated in this order.

[0057] (Third Embodiment) Next, the differences between the third embodiment and the other embodiments will be mainly described. Figure 6 is a cross-sectional view of the reflector 300 according to the third embodiment. In the reflector 300 according to the third embodiment, the mirror layer 110, the fiber layer 120, and the porous layer 130 are laminated in this order along the lamination direction, and further, the fiber layer 140, the porous layer 150, the fiber layer 160, and the porous layer 170 are laminated in this order.

[0058] The number of layers and the thickness of each layer in the lamination direction of the reflector 300 in the third embodiment are not limited as long as the function (lightweight, strength, and thermal diffusivity) is not hindered. For example, the fiber layer and the porous layer may each be laminated in 3 layers, or each in 5 layers. Furthermore, the thickness of the reflector 300 in the lamination direction is preferably 150 μm or more and 3000 μm or less.

[0059] Thus, in the reflector 300 of the third embodiment, multiple layers of fiber layers and porous layers are alternately laminated. This makes the reflector 300 lighter and also provides excellent rigidity.

[0060] Furthermore, the reflector 300 of the third embodiment is not particularly limited, but can be manufactured by combining the manufacturing method of the reflector 200 of the second embodiment.

[0061] Furthermore, the reflector of the present invention may include layers other than the fiber layer and the porous layer, as long as they do not interfere with the function of the reflector. Examples include an enhanced reflectivity layer, a protective layer, diamond-like carbon, a graphite layer, and the like.

[0062] (Fourth Embodiment) Next, the fourth embodiment will be described, mainly focusing on the differences from the other embodiments. Figure 7 is a cross-sectional view of the reflector 400 according to the fourth embodiment. In the reflector 400 according to the fourth embodiment, the mirror layer 110 and the composite layer 410 are laminated in this order along the lamination direction. That is, the composite layer 410 is positioned on the second surface 112 of the mirror layer 110. Here, the composite layer 410 is made of fibers and a porous material.

[0063] (Composite Layer) The composite layer contains inorganic materials and is a composite of the material used in the fiber layer and the material used in the porous layer. For example, a mixed paper of fibers and inorganic fine particles can be used, and it is possible to adjust it to the required properties of the reflector 400, such as lightness, warping reduction, and uniform heat distribution. The materials that make up the composite layer can be any of the above materials as long as they do not interfere with the necessary functions.

[0064] As described above, the reflector 400 of the fourth embodiment is provided with a composite layer 410 of fibers and a porous material. This makes the reflector 400 lighter and also provides excellent rigidity. Furthermore, it has excellent heat resistance against heat from laser light and can diffuse heat in the planar direction.

[0065] The method for manufacturing the composite layer is not particularly limited, but for example, it can be produced by wet-forming a slurry aqueous solution containing fibers and inorganic fine particles, followed by drying and sintering.

[0066] The application examples of each reflector described above are not limited to laser processing machines. Other examples include beam steering, imaging, laser marking, and more.

[0067] <Examples 1 to 7> The reflector 100 according to the first embodiment was manufactured by the following steps.

[0068] As shown in Table 1, the reflector 100 of Example 1 was fabricated. Carbon nanotubes (CNTs) (product name TUBALL 01RW03, manufactured by OCSiAl, with a CNT diameter of 2 nm) were dispersed in a solvent to prepare a carbon fiber-containing slurry formed by the aggregation of CNTs, and a fiber sheet (thickness 50 μm, packing density 20%) was prepared by a wet papermaking method. Next, a thermosetting epoxy resin sheet with a thickness of 10 μm was laminated to one side of this fiber sheet, and the sheet was left to stand for 1 hour in a hot air circulation dryer set to 180°C to heat-cur the thermosetting epoxy resin sheet. At this time, a 250 μm thick polyester film treated with silicone release was laminated to the side of the thermosetting epoxy resin sheet opposite to the side in contact with the fiber sheet (to make the surface of the thermosetting epoxy resin sheet flat after heat curing). After that, the fiber sheet was removed from the hot air circulation dryer, the polyester film was peeled off, and a fiber layer 120 was obtained. At this time, the thickness of the fiber layer 120 was 100 μm. Next, a mirror layer 110 with a thickness of 50 μm was formed by vacuum deposition using a vacuum deposition apparatus (Shimadzu Corporation, E-250DT) and silver to obtain a reflector plate 100. The average fiber diameter of the carbon fibers contained in the slurry after the slurry preparation and the average fiber diameter of the carbon fibers after the formation of the reflector plate 100 were both 0.6 μm.

[0069] The reflectors 100 of Examples 2 to 7 shown in Table 1 were manufactured using the same manufacturing method as in Example 1 described above. In Examples 2 and 3, the reflectors 100 were manufactured in the same manner as in Example 1, except that fiber sheets with thicknesses of 15 μm and 480 μm were used, respectively. In Examples 4 to 7, the reflectors 100 were manufactured in the same manner as in Example 1, except that fiber sheets with packing ratios of 2%, 5%, 40%, and 50%, respectively, were used, respectively.

[0070] <Evaluation> The evaluation results for the lightweight properties and thermal diffusivity of the reflectors according to Examples 1 to 7 are shown in Table 1 below.

[0071] (Evaluation of Lightweight Properties) The lightweight properties of Examples 1 to 7 were evaluated. Specifically, the bulk density of each reflector 100 was measured using a geometric measurement method and used for the evaluation of lightweight properties.

[0072] (Evaluation of Thermal Diffusivity) Thermal diffusivity was evaluated for Examples 1 to 7. Specifically, for each reflector 100, the fiber layer 120 was punched out to a size of 10 mmφ from the direction perpendicular to the reflector 100, and measured using a flash thermal conductivity measuring device (NETZSCH LFA447 Nanoflash) (n=3). The average value of the obtained thermal conductivity in the surface direction was used to evaluate thermal diffusivity.

[0073] As shown in Table 1, lightweight properties and thermal diffusivity were confirmed in all of the reflectors from Example 1 to Example 7.

[0074]

[0075] <Examples 8 to 24> The reflector 200 according to the second embodiment was manufactured by the following steps.

[0076] As shown in Table 2, the reflector 200 of Example 8 was fabricated. Specifically, alumina particles (Advanced Alumina AA-18, manufactured by Sumitomo Chemical Co., Ltd., average particle size 20 μm) were used for the porous layer 130. Specifically, 800 parts by weight of these alumina particles were added to 100 parts by weight of binder resin (Orix KC1300, manufactured by Kyoei Chemical Co., Ltd., 20% toluene solution), and the mixture was stirred for 1 hour to prepare a slurry solution. This slurry solution was placed in a polypropylene container so that the thickness after sintering would be 1000 μm, and the mixture was left to stand in a constant temperature bath set to 100°C for 5 hours to solidify the slurry solution. After that, it was heated in an electric furnace set to 1200°C for 2 hours to obtain the porous layer 130. Here, carbon nanotubes (CNTs) (product name TUBALL 01RW03, manufactured by OCSiAl, with a CNT diameter of 2 nm) were dispersed in a solvent to prepare a carbon fiber-containing slurry formed by the aggregation of CNTs. A fiber sheet (thickness 50 μm, packing density 20%) was then fabricated using a wet papermaking method. This fiber sheet was laminated to one side of a porous layer 130 and left to stand for 1 hour in a hot air circulation dryer set to 400°C to fuse the fiber sheet to the porous layer 130. Next, a 10 μm thick thermosetting epoxy resin sheet was laminated to one side of this fiber sheet and left to stand for 1 hour in a hot air circulation dryer set to 180°C to heat-cur the thermosetting epoxy resin sheet. At this time, a 250 μm thick polyester film treated with silicone release was laminated to the side of the thermosetting epoxy resin sheet opposite to the side in contact with the fiber sheet (to make the surface of the thermosetting epoxy resin sheet flat after heat curing). Subsequently, the fiber sheet was removed from the hot air circulation dryer, the polyester film was peeled off, and a fiber layer 120 was obtained. At this time, the thickness of the fiber layer 120 was 100 μm. Next, a mirror layer 110 with a thickness of 50 μm was formed by vacuum deposition using a vacuum deposition apparatus (Shimadzu Corporation, E-250DT) and silver, and a reflector plate 200 was obtained. The average fiber diameter of the carbon fibers contained in the slurry after the slurry preparation and the average fiber diameter of the carbon fibers after the formation of the reflector plate 200 were both 0.6 μm.

[0077] Reflectors 100 for Examples 9 to 24 shown in Table 2 were fabricated using the same manufacturing method as in Example 8 described above. In Examples 9 to 12, the reflectors 200 were fabricated in the same manner as in Example 8, except that fiber sheets with a packing ratio of 2%, 5%, 40%, and 50% were used, respectively. In Examples 13 to 16, the reflectors 200 were fabricated in the same manner as in Example 8, except that slurry solutions were prepared so that the packing ratio of the porous layer 130 was 10%, 20%, 80%, and 90%, respectively. In Examples 17 to 20, the reflectors 200 were fabricated in the same manner as in Example 8, except that fiber sheets with thicknesses of 30 μm, 50 μm, 500 μm, and 1500 μm were used, respectively. In Examples 21 to 24, the reflectors 200 were fabricated in the same manner as in Example 8, except that the porous layer 130 was fabricated so that its thickness was 300 μm, 500 μm, 2000 μm, and 3000 μm, respectively.

[0078] <Evaluation> Table 2 shows the evaluation results for lightness, thermal diffusivity, and strength of the reflectors according to Examples 8 to 24.

[0079] (Evaluation of Lightweight Properties) The lightweight properties of Examples 8 to 24 were evaluated. Specifically, the bulk density of each reflector 200 was measured using a geometric measurement method and used for the evaluation of lightweight properties.

[0080] (Evaluation of thermal conductivity in the planar direction) Thermal conductivity was evaluated for Examples 8 to 24. Specifically, each reflector 200 was punched out to a size of 10 mmφ from the direction perpendicular to the reflector 200, and the thermal diffusivity was measured using a flash thermal diffusivity measuring device (NETZSCH LFA447 Nanoflash) (n=3). The average value of the obtained thermal conductivity in the planar direction was used to evaluate thermal conductivity.

[0081] (Evaluation of Strength) Strength was evaluated in Examples 8 to 24. Specifically, each reflector 200 shown in Table 2 was cut to a width of 10 mm and a length of 30 mm to obtain test specimens. The obtained test specimens were subjected to a three-point bending test (JIS K7171) with a support distance of 3.0 mm and a test speed of 1.0 mm / min to obtain the value of the bending modulus of elasticity. For evaluation, the average value of the strength (n=3) was used: bending modulus of elasticity × thickness / 1000.

[0082] As shown in Table 2, lightweight properties and thermal diffusivity were confirmed for all reflectors from Examples 8 to 24. Furthermore, sufficient strength was confirmed for all reflectors in each example.

[0083]

[0084] <Examples 25 to 30> Using the manufacturing method of the second embodiment, the reflector 500 according to the fifth embodiment was manufactured with the following configuration.

[0085] As shown in Table 3, the reflector 500 of Example 25 was fabricated. Specifically, alumina particles (Advanced Alumina AA-18, manufactured by Sumitomo Chemical Co., Ltd., average particle size 20 μm) were used for the porous layer 130. Specifically, 800 parts by weight of these alumina particles were added to 100 parts by weight of binder resin (Orix KC1300, manufactured by Kyoei Chemical Co., Ltd., 20% toluene solution), and the mixture was stirred for 1 hour to prepare a slurry solution. This slurry solution was placed in a polypropylene container so that the thickness after sintering would be 1000 μm, and the mixture was left to stand in a constant temperature bath set to 100°C for 5 hours to solidify the slurry solution. After that, it was heated in an electric furnace set to 1400°C for 2 hours to obtain the porous layer 130. Next, a thermosetting epoxy resin sheet with a thickness of 10 μm was laminated to one side of this porous layer 130, and the thermosetting epoxy resin sheet was heated and cured by leaving it to stand in a hot air circulation dryer set to 180°C for 1 hour. At this time, a 250 μm thick polyester film treated with silicone release was laminated to the side of the thermosetting epoxy resin sheet opposite to the side in contact with the porous layer 130 (to make the surface of the thermosetting epoxy resin sheet flat after heat curing). Then, the porous layer 130 was removed from the hot air circulation dryer, the polyester film was peeled off, and the porous layer 130 was obtained. At this time, the thickness of the porous layer 130 was 1000 μm. Next, a mirror layer 110 with a thickness of 50 μm was formed by vacuum deposition using a vacuum deposition apparatus (Shimadzu Corporation, E-250DT) and silver to obtain a reflector 500.

[0086] Reflectors 500 for Examples 26 to 30 shown in Table 3 were fabricated using the same manufacturing method as in Example 25 described above. In Examples 26 to 29, the reflectors 500 were fabricated in the same manner as in Example 25, except that the slurry solution was prepared so that the packing ratio of the porous layer 130 was 10%, 20%, 80%, and 90%, respectively. In Example 30, the reflectors 500 were fabricated in the same manner as in Example 25, except that silica particles (manufactured by Nippon Steel Chemical & Material Co., Ltd., HS-106, average particle size 21 μm) were used instead of alumina particles, and the electric furnace temperature was set to 1000°C.

[0087] <Evaluation> Table 3 shows the evaluation results for the lightness and strength of the reflectors according to Examples 25 to 30.

[0088] (Evaluation of Lightweight Properties) The lightweight properties of Examples 25 to 30 were evaluated. Specifically, the bulk density of each reflector 500 was measured using a geometric measurement method and used for the evaluation of lightweight properties.

[0089] (Evaluation of Strength) Strength was evaluated in Examples 25 to 30. Specifically, each reflector 500 shown in Table 3 was cut to a width of 10 mm and a length of 30 mm to obtain test specimens. The obtained test specimens were subjected to a three-point bending test (JIS K7171) with a support distance of 3.0 mm and a test speed of 1.0 mm / min to obtain the value of the bending modulus of elasticity. For evaluation, the average value of the strength (n=3) was used: bending modulus of elasticity × thickness / 1000.

[0090] As shown in Table 3, lightweight properties and sufficient strength were confirmed in all of the reflectors in Examples 25 to 30.

[0091]

Claims

1. A reflector comprising: a mirror layer having a first surface for reflecting light rays; and a fiber layer disposed on a second surface of the mirror layer opposite to the first surface.

2. The reflector according to claim 1, wherein in the fiber layer, the fibers are substantially oriented in the planar direction.

3. The reflector according to claim 1 or 2, wherein a porous layer is disposed on a second surface of the fiber layer opposite to the first surface to which the mirror layer is joined.

4. The reflector according to claim 3, wherein the fiber layer and the porous layer are alternately laminated on the second surface side of the mirror layer.

5. The reflector according to any one of claims 1 to 4, wherein the fiber layer includes carbon fibers.

6. A reflector comprising: a mirror layer having a first surface for reflecting light rays; and a porous layer disposed on a second surface of the mirror layer opposite to the first surface.

7. A reflector comprising: a mirror layer having a first surface for reflecting light rays; and a composite layer disposed on a second surface of the mirror layer opposite to the first surface, the composite layer comprising fibers and a porous material.

8. The reflector according to any one of claims 1 to 5, wherein the thermal conductivity in the planar direction of the fiber layer is 10 W / m·K or more.

9. The reflector according to any one of claims 1 to 5, wherein the packing ratio of the fiber layer is 2% or more and 60% or less.

10. The reflector according to any one of claims 1 to 5, wherein the average aspect ratio of the fibers in the fiber layer is 5 or more and 1000 or less.

11. The reflector according to any one of claims 1 to 5, wherein the thickness of the fiber layer is 10 μm or more and 1000 μm or less.

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