Galvo mirror and method for manufacturing galvo mirror

Abstract

A galvo mirror (100) comprises: a mirror surface (1) that has a front face (1a) serving as a mirror face and a back face (1b) having a planar shape; a reinforcing plate (2) that is provided on the back face (1b) side of the mirror surface (1), at a distance from the back face (1b); a plurality of types of core materials (3) that include a foamlike core (3a) and honeycomb core (3b), which are positioned sandwiched between the mirror surface (1) and the reinforcing plate (2) and are fixed to the back face (1b) of the mirror surface (1); and a mirror fixing part (4) that is positioned sandwiched between the mirror surface (1) and the reinforcing plate (2), and is formed from a different material from the core materials (3). Adjacent members among the mirror surface (1), the reinforcing plate (2), the core materials (3), and the mirror fixing part (4) are fixed via adhesive layers (5), and the mirror surface (1), the reinforcing plate (2), the core materials (3), and the mirror fixing part (4) are unified.

Description

Galvanometer mirror and method for manufacturing the same

[0001] The present disclosure relates to a galvanometer mirror of a galvanometer scanner used in a laser processing machine or the like, and a method for manufacturing the galvanometer mirror.

[0002] As the integration of circuit boards for mobile phones and electronic devices becomes more advanced, there is a demand for higher precision and speed in laser processing machines. Laser processing machines that drill holes in circuit boards use galvanometer scanners that deflect and drive the laser, and increasing the speed of galvanometer scanners is essential for increasing the processing speed of laser processing machines.

[0003] A conventional galvanometer scanner generally includes a stator with a coil, a rotor with a permanent magnet and a rotor shaft, and a galvanometer mirror attached to the rotor shaft. The stator is fixed to a housing or the like, and the permanent magnet receives the driving torque generated by the coil, causing the rotor to rotate, which in turn rotates the galvanometer mirror. While the rotor rotates continuously, the galvanometer mirror rotates within a range of ±10 degrees from a reference position.

[0004] When a galvanometer scanner is applied to a laser processing machine that continuously drills holes in circuit boards, it repeats acceleration, deceleration, and then stopping. Operating the galvanometer scanner at high speed increases the frequency of the drive current. This causes eddy currents to flow in the permanent magnet, generating eddy losses and increasing the temperature of the permanent magnet. If the temperature of the permanent magnet becomes excessively high, thermal demagnetization occurs, degrading the magnetic properties and hindering the operation of the galvanometer scanner.

[0005] Furthermore, when a galvanometer scanner is operated at high speed, the load on the galvanometer mirror and the rotor shaft increases, making it necessary to firmly fix the galvanometer mirror to the rotor shaft to prevent misalignment between the galvanometer mirror and the rotor shaft. Therefore, a conventional structure has been adopted in which a mirror fixing portion is provided on the galvanometer mirror, into which a portion of the rotor shaft fits, and the galvanometer mirror is mechanically fixed to the rotor shaft. However, with this structure, strain occurs in the mirror fixing portion when the galvanometer mirror and the rotor shaft are fixed, and this strain is transmitted to the mirror surface of the galvanometer mirror, causing strain in the mirror surface of the galvanometer mirror. This deteriorates the precision of the mirror surface of the galvanometer mirror and leads to a deterioration in processing accuracy.

[0006] In view of this situation, Patent Document 1 discloses a galvanometer mirror that suppresses deterioration of the accuracy of the mirror surface when fixing the galvanometer mirror to the rotor shaft. The technology disclosed in Patent Document 1 uses a low-density, highly rigid metal material such as beryllium as the material for the galvanometer mirror, which is equipped with a mirror surface having optical properties, a mirror fixing portion for fixing the rotor shaft, and a rib as a reinforcing structure, and by making a notch in the rib near the mirror fixing portion, a structure is created in which distortion in the mirror fixing portion is less likely to be transmitted to the mirror surface of the galvanometer mirror, thereby reducing distortion occurring on the mirror surface of the galvanometer mirror.

[0007] Patent No. 3531554

[0008] However, in the technology disclosed in Patent Document 1, notches are made in the ribs near the mirror fixing portion, reducing the rigidity of the notched portions. This results in increased wobble of the galvanometer mirror during high-speed operation, resulting in a problem of misalignment of the machining position. To reduce this wobble, the galvanometer mirror must be made lighter and have lower inertia. To achieve this, the ribs and mirror surface must be made thinner. However, thinning the mirror surface significantly increases the difference in rigidity between the ribbed and non-ribbed portions on the backside of the mirror. The ribbed portions, due to their high rigidity, are subjected to a load during mirror polishing, while the non-ribbed portions, due to their low rigidity, deflect and release the load during mirror polishing, making them difficult to polish. This results in the problem of inconsistent polishing of the mirror surface and the inability to achieve the desired flatness. Furthermore, thinning the mirror surface reduces the rigidity of the mirror surface, making it more susceptible to deformation during mirror operation, making it difficult to increase the speed of the galvanometer scanner.

[0009] The present disclosure has been made in view of the above, and aims to provide a galvanometer mirror that can achieve a lightweight and highly accurate mirror surface while ensuring rigidity that makes it difficult to deform.

[0010] In order to solve the above-mentioned problems and achieve the object, the galvanometer mirror according to the present disclosure includes a mirror surface, a reinforcing plate, multiple types of core materials, and a mirror fixing portion. The mirror surface has a front surface that is a mirror surface and a planar rear surface facing away from the front surface. The reinforcing plate is provided on the rear side of the mirror surface at a distance from the rear surface. The multiple types of core materials are sandwiched between the mirror surface and the reinforcing plate and include a foam core and a honeycomb core fixed to the rear surface of the mirror surface. The mirror fixing portion is sandwiched between the mirror surface and the reinforcing plate and is formed of a material different from the core material, and fixes the galvanometer mirror to another member. Adjacent members of the mirror surface, the reinforcing plate, the core material, and the mirror fixing portion are fixed to each other via an adhesive layer, thereby integrating the mirror surface, the reinforcing plate, the core material, and the mirror fixing portion.

[0011] The galvanometer mirror according to the present disclosure has the advantage of being able to achieve a lightweight and highly accurate mirror surface while ensuring rigidity that makes it difficult to deform.

[0012] a perspective view of an example of a manufacturing process for the galvanometer mirror according to the first embodiment; a rear view of the galvanometer mirror according to the first embodiment; a cross-sectional view taken along line V-V shown in FIG. 4; a flowchart showing an example of a manufacturing process for the galvanometer mirror according to the first embodiment; a diagram showing an example of a manufacturing process for the mirror surface in the first embodiment; a perspective view of an example of a galvanometer mirror formed from a single material according to the prior art; a perspective view of the galvanometer mirror shown in FIG. 9 in a deformed state after mirror polishing; a perspective view of a galvanometer mirror having a sandwich structure according to the prior art in a deformed state; an enlarged view of part A shown in FIG.

[0013] Hereinafter, a galvanometer mirror and a method for manufacturing the galvanometer mirror according to an embodiment will be described in detail with reference to the drawings.

[0014] First Embodiment. FIG. 1 is a side view showing a galvanometer mirror 100 according to the first embodiment. FIG. 2 is a side view showing the galvanometer mirror 100 according to the first embodiment with its components separated. FIG. 3 is a perspective view showing the galvanometer mirror 100 according to the first embodiment. FIG. 4 is a rear view showing the galvanometer mirror 100 according to the first embodiment. The galvanometer mirror 100, together with a stator, a rotor, and the like (not shown), constitutes a galvanometer scanner and is a component that reflects a laser beam (not shown). The galvanometer mirror 100 rotates within a specific range of deflection angles due to rotation of the rotor. The rotation of the galvanometer mirror 100 can change the irradiation position of the laser beam on a workpiece (not shown). As shown in FIGS. 1 and 2 , the galvanometer mirror 100 includes a mirror surface 1, a reinforcing plate 2, multiple types of core materials 3, a mirror fixing portion 4, and an adhesive layer 5. In the following description, the length direction of the galvanometer mirror 100 is defined as the X-axis direction, the thickness direction of the galvanometer mirror 100 is defined as the Y-axis direction, and the width direction of the galvanometer mirror 100 is defined as the Z-axis direction. The X-axis direction, Y-axis direction, and Z-axis direction are perpendicular to each other.

[0015] As shown in Figure 2, the mirror surface 1 is a plate-like member having a front surface 1a that serves as a mirror surface and a flat rear surface 1b that faces away from the front surface 1a. The rear surface 1b itself does not have a reinforcing structure such as a rib that is conventionally provided. The mirror surface 1 has a specific elastic modulus (GPa cm), which is the value obtained by dividing the elastic modulus by the density (bulk specific gravity). 3It is preferable that the mirror surface 1 be formed from a material having a high surface roughness (Tc / g) and good mirror polishing processability. Specifically, it is preferable that the mirror surface 1 be a ceramic plate of any of alumina, sapphire, boron carbide, silicon nitride, aluminum nitride, silicon carbide, B4C-TiB2, and beryllium, or a wafer of single crystal silicon carbide or single crystal silicon, or a single crystal silicon wafer. For example, when a single crystal silicon carbide wafer is used for the mirror surface 1, the mirror-finished mirror surface 1 can be obtained by trimming the crystalline silicon carbide wafer and then mirror polishing it. The thickness of the mirror surface 1 is preferably less than 1 mm, and more preferably 400 μm or less.

[0016] The reinforcing plate 2 is a plate-like member provided on the rear surface 1b side of the mirror surface 1 at a distance from the rear surface 1b. The reinforcing plate 2 is preferably formed of a material with a low bulk density and high rigidity. Specifically, the material of the reinforcing plate 2 is preferably carbon fiber reinforced plastics (CFRP) using carbon fibers with an elastic modulus of 600 GPa or more. The specific elastic modulus of the carbon fiber reinforced plastic is preferably 100 or more. The thickness of the reinforcing plate 2 is preferably less than 1 mm. The reinforcing plate 2 has a bulk density of 1.85 g / cm. 3 It is preferable that the modulus of elasticity of the reinforcing plate 2 is 120 GPa or more.

[0017] The multiple types of core materials 3 are sandwiched between the mirror surface 1 and the reinforcing plate 2 and include a foam core 3a and a honeycomb core 3b. In this embodiment, there are two types of core materials 3: the foam core 3a and the honeycomb core 3b.

[0018] The foam core 3a is a plate-like member fixed to the back surface 1b of the mirror surface 1. The foam core 3a is a plate material made of foamed hard plastic or the like. The foam core 3a is preferably made of a material with isotropic properties, such as a closed-cell foamed hard plastic. Specifically, the material of the foam core 3a is preferably a material with a low bulk density and a modulus of elasticity / (bulk density)^3 value of 100 GPa or more, such as ROHACELL 110HP manufactured by EVONIC, and more preferably a closed-cell structural material. The material of the foam core 3a may also be GRAFOAM, a carbon foam, or a material with a bulk density of 0.4 g / cm. 3 As long as the foam material has a modulus of elasticity / (bulk specific gravity)^3 value of 100 GPa or more, metal, ceramics, etc. may be used. As the material for the core material 3 fixed to the rear surface 1b of the mirror surface 1, a foam core 3a is preferred over a structural material with large variations in density and roughness at the visual level, such as a honeycomb core 3b. The thickness of the foam core 3a is preferably 2 mm or more and less than 10 mm, and more preferably less than 5 mm. The foam core 3a has a bulk specific gravity of 0.4 g / cm 3 3, a notch 3c into which part of the mirror fixing part 4 fits is formed at one end of the foam core 3a in the X-axis direction.

[0019] As shown in FIG. 2, the honeycomb core 3b is a plate-like member provided between the foam core 3a and the reinforcing plate 2. The honeycomb core 3b is preferably made of carbon fiber reinforced plastic or the like. Specifically, the material of the honeycomb core 3b is preferably a material with a high specific modulus of elasticity, such as honeycomb UCF-137-3 / 8-10 manufactured by Ultracor Corporation. The bulk density of the honeycomb core 3b is preferably 0.2 g / cm. 3Preferably, the thickness of the honeycomb core 3b is 3 mm or more and less than 15 mm, and more preferably less than 10 mm. As shown in Fig. 3, a notch 3d into which part of the mirror fixing part 4 fits is formed at one end of the honeycomb core 3b in the X-axis direction.

[0020] As shown in FIG. 1 , the mirror fixing portion 4 is sandwiched between the mirror surface 1 and the reinforcing plate 2 and serves to fix the galvanometer mirror 100 to another member (not shown). The other member is, for example, a rotor shaft. The mirror fixing portion 4 is formed of a material different from the core material 3. As shown in FIG. 3 , the mirror fixing portion 4 is fitted into the cutout portion 3 c of the foam core 3 a and the cutout portion 3 d of the honeycomb core 3 b. The mirror fixing portion 4 is disposed adjacent to the foam core 3 a and the honeycomb core 3 b in the X-axis direction and the Z-axis direction. The mirror fixing portion 4 is preferably formed of a material with a low bulk density and a high elastic modulus. Specifically, the material of the mirror fixing portion 4 is C / SiC (bulk density: 2.95 g / cm ) which is a composite of silicon carbide and carbon fiber. 3 , elastic modulus: 350 GPa), the bulk density is 4 g / cm 3 It is preferable that the surface roughness is less than 1000, the modulus of elasticity is 300 GPa or more, and the specific modulus of elasticity is 100 or more. In addition to C / SiC, the material of the mirror surface 1 may be ceramics such as alumina, boron carbide, silicon nitride, aluminum nitride, silicon carbide, and B4C-TiB2.

[0021] The mirror fixing portion 4 has a gripping portion 4a that grips another member. The gripping portion 4a is not covered by the mirror surface 1 and the reinforcing plate 2, but is exposed from the mirror surface 1 and the reinforcing plate 2. In this embodiment, the shape of the gripping portion 4a is rectangular, but is not particularly limited. If the mirror surface 1 and the reinforcing plate 2 directly grip (fix) another member, this is undesirable because strain generated when fixing the galvanometer mirror 100 to the other member is likely to be transmitted to the mirror surface 1. However, in this embodiment, the other member is directly gripped by the gripping portion 4a that is exposed from the mirror surface 1 and the reinforcing plate 2, so strain generated when fixing the galvanometer mirror 100 to the other member is less likely to be transmitted to the mirror surface 1.

[0022] Each adhesive layer 5 shown in FIG. 2 is a layer that secures adjacent components of the galvanometer mirror 100 together. That is, adjacent components among the mirror surface 1, the reinforcing plate 2, the core material 3, and the mirror fixing portion 4 are secured together via the adhesive layer 5, thereby integrating the mirror surface 1, the reinforcing plate 2, the core material 3, and the mirror fixing portion 4. The adhesive layer 5 is, for example, a film adhesive or a liquid adhesive made of a resin sheet. In this embodiment, there are three adhesive layers 5. When distinguishing between the three adhesive layers 5, they are referred to as the first adhesive layer 5a, the second adhesive layer 5b, and the third adhesive layer 5c. The first adhesive layer 5a secures the back surface 1b of the mirror surface 1 to the foam core 3a and the mirror fixing portion 4. The second adhesive layer 5b secures the foam core 3a to the honeycomb core 3b. The third adhesive layer 5c secures the honeycomb core 3b and the mirror fixing portion 4 to the reinforcing plate 2.

[0023] As shown in Figures 3 and 4, the external shape of the galvanometer mirror 100 is generally elliptical (oval) in this embodiment, but this may be modified as appropriate. Each component of the galvanometer mirror 100 has a curved or tapered outer periphery and a flat bonding surface for bonding to adjacent components. Figure 5 is a cross-sectional view taken along line V-V in Figure 4. As shown in Figure 5, the XY cross-sectional shape of the galvanometer mirror 100 is trapezoidal in this embodiment, with the area of ​​the reinforcing plate 2 being smaller than the area of ​​the mirror surface 1, but this may be modified as appropriate. Note that the mirror fixing portion 4 is not shown in Figure 5.

[0024] Next, a manufacturing method of the galvanometer mirror 100 according to the first embodiment will be described with reference to Fig. 6 to Fig. 8. Fig. 6 is a flowchart showing an example of a manufacturing process for the galvanometer mirror 100 according to the first embodiment. Fig. 7 is a diagram showing an example of a manufacturing process for the mirror surface 1 according to the first embodiment. Fig. 8 is a diagram showing an example of an assembly procedure for the galvanometer mirror 100 according to the first embodiment.

[0025] The manufacturing method of the galvanometer mirror 100 includes a preparation step, a fixing step, a coating step, and a covering step.

[0026] The preparation process is a process of preparing a mirror surface 1, multiple types of core materials 3, a reinforcing plate 2, and a mirror fixing portion 4. As shown in Fig. 6, the preparation process includes a mirror surface forming process, a foam core forming process, a honeycomb core forming process, a reinforcing plate forming process, and a mirror fixing portion forming process.

[0027] In the mirror surface forming process, a single crystal ingot 1c such as SiC shown in FIG. 7 is prepared (step S11), and the single crystal ingot 1c is sliced ​​to obtain wafers 1d (step S12). Multiple wafers 1d are obtained from one single crystal ingot 1c. In the mirror surface forming process, each wafer 1d is trimmed to a desired shape (step S13) to obtain trimmed members 1e. Multiple trimmed members 1e are obtained from one wafer 1d. A mirror polishing process is then performed (step S14) to mirror polish each trimmed member 1e using a lapping device or the like. This results in a mirror-finished mirror surface 1.

[0028] 6, a foamed bulk material such as hard plastic is sliced ​​to a predetermined thickness (step S21), and then trimmed to fit the shape of the mirror surface 1 (step S22). This produces the foam core 3a. Note that because the bulk material is a low-density foam material, it can be easily processed using a standard processing machine.

[0029] In the honeycomb core forming process, a honeycomb material made of carbon fiber reinforced plastic or the like is sliced ​​to a predetermined thickness (step S31), and then the honeycomb material is trimmed to fit the shape of the foam core 3a (step S32), thereby obtaining the honeycomb core 3b.

[0030] In the reinforcing plate forming process, a plate is formed using high-rigidity carbon fiber (step S41), and then the plate is trimmed to fit the shape of the mirror surface 1 (step S42). In this way, the reinforcing plate 2 is obtained.

[0031] In the mirror fixing portion forming step, ceramic is formed into a block to obtain a bulk material (step S51), and then the bulk material is trimmed (step S52). In this way, the mirror fixing portion 4 is obtained.

[0032] The fixing process (step S61) is a process in which adjacent components among the mirror surface 1, reinforcing plate 2, core material 3, and mirror fixing portion 4 shown in FIG. 8 are fixed together with adhesive layers 5 to integrate the mirror surface 1, reinforcing plate 2, core material 3, and mirror fixing portion 4. In the fixing process, the mirror surface 1, first adhesive layer 5a, foam core 3a, second adhesive layer 5b, honeycomb core 3b, mirror fixing portion 4, third adhesive layer 5c, and reinforcing plate 2 are stacked in this order. Specifically, in the fixing process, first, the mirror surface 1 is prepared as shown in the upper left of FIG. 8. Next, the first adhesive layer 5a is applied to the back surface 1b of the mirror surface 1. Next, the foam core 3a is fixed to the back surface 1b of the mirror surface 1 via the first adhesive layer 5a.

[0033] Next, as shown in the upper center of Figure 8, a second adhesive layer 5b is applied to the surface of the foam core 3a facing away from the first adhesive layer 5a. Next, the honeycomb core 3b is fixed to the foam core 3a via the second adhesive layer 5b. Next, the mirror fixing portion 4 is placed in the cutout portion 3c of the foam core 3a and the cutout portion 3d of the honeycomb core 3b, and the mirror fixing portion 4 is placed on the exposed surface 5d of the first adhesive layer 5a, and the mirror fixing portion 4 is fixed to the back surface 1b of the mirror surface 1 via the first adhesive layer 5a. The exposed surface 5d of the first adhesive layer 5a is the portion exposed through the cutout portions 3c and 3d.

[0034] Next, as shown in the upper right of Figure 8, a third adhesive layer 5c is applied to the surface of the honeycomb core 3b facing away from the second adhesive layer 5b and the surface of the mirror fixing portion 4 facing away from the first adhesive layer 5a. Next, a reinforcing plate 2 is placed on the opposite side of the honeycomb core 3b and mirror fixing portion 4, sandwiching the third adhesive layer 5c between them. Next, the reinforcing plate 2 is fixed to the honeycomb core 3b and mirror fixing portion 4 via the third adhesive layer 5c. This integrates the mirror surface 1, reinforcing plate 2, foam core 3a, honeycomb core 3b, and mirror fixing portion 4. Here, the first adhesive layer 5a, second adhesive layer 5b, and third adhesive layer 5c are film-like adhesives made of resin sheets.

[0035] The coating step (step S62) shown in Fig. 6 is a step of forming a coating on the mirror surface by depositing a metallic material on the mirror surface of the mirror surface 1 or by sputtering the mirror surface after the fixing step. That is, the coating step is a step of applying an enhanced reflection coating. The coating is a metallic film.

[0036] The coating step (step S63) is a step of further coating the mirror surface with a dielectric multilayer coating. In other words, the coating step is a step of applying a reflection-enhancing coating. By performing the coating step and the coating step, the reflectance of the mirror surface of the mirror surface 1 can be increased. By performing the above steps, the galvanometer mirror 100 shown in FIG. 1 is manufactured.

[0037] Next, the effects of the galvanometer mirror 100 according to the first embodiment will be described.

[0038] First, with reference to FIGS. 9 to 12 , conventional galvanometer mirrors 200 and 300 will be described. FIG. 9 is a perspective view showing an example of a conventional galvanometer mirror 200 formed from a single material. FIG. 10 is a perspective view showing the deformed state of the galvanometer mirror 200 shown in FIG. 9 after mirror polishing. FIG. 11 is a perspective view showing the deformed state of a conventional sandwich-structured galvanometer mirror 300. FIG. 12 is an enlarged view of portion A shown in FIG. 11 . In the conventional galvanometer mirror 200 shown in FIG. 9 , the back surface 230 of the mirror surface 210 is ground to reduce its weight. Meanwhile, the back surface 230 of the mirror surface 210 is provided with ribs 240, each of which includes a spine structure 250 extending in the X-axis direction at the center in the Z-axis direction and a plurality of rib reinforcements 260 extending from the spine structure 250 toward the outer periphery of the mirror surface 210. This reduces the reduction in rigidity of the galvanometer mirror 200 due to the weight reduction. In a conventional galvanometer mirror 200, when the back surface 230 of the mirror surface 210 is lightened and then the front surface 220 of the mirror surface 210 is mirror-polished, the rigidity of the mirror surface 210 becomes uneven due to the influence of the ribs 240. As a result, the amount of deflection due to the surface pressure during the mirror polishing process differs between the areas where the ribs 240 are present and the areas where the ribs 240 are not present. The areas where the ribs 240 are present have high rigidity and can be polished, while the areas where the ribs 240 are not present have low rigidity and are therefore bent and difficult to polish. As a result, dimples 270, as shown in FIG. 10, are formed, making it impossible to obtain a high-precision mirror surface. On the other hand, in a conventional galvanometer mirror 200, when the back surface 230 of the mirror surface 210 is lightened after the mirror polishing process, distortion occurs during the lightening process, degrading the precision of the mirror surface of the mirror surface 210. As a result, it is impossible to obtain a high-precision mirror surface. In other words, the conventional galvanometer mirror 200 cannot achieve both a lighter weight and high precision of the mirror surface.

[0039] Furthermore, as shown in FIG. 11 , when the galvanometer mirror 300 has a sandwich panel structure in which a honeycomb core 320 with a large cell size and low core density is sandwiched between two thin surface plates 310 to reduce weight, the sandwich panel structure is affected by the adhesive when the surface plate 310 and honeycomb core 320 are fixed together. This causes dimples 330 that trace the cell pattern of the honeycomb core 320 to appear in the surface plate 310, as shown in FIG. 12 , resulting in a decrease in the precision of the mirror surface of the surface plate 310. To solve this decrease in the precision of the mirror surface, it is necessary to either reduce the cell size of the honeycomb core 320 to increase its density, or to increase the thickness of the surface plate 310 to increase its rigidity. However, doing so increases the weight of the galvanometer mirror 300. In other words, the galvanometer mirror 300 according to the prior art cannot achieve both a reduction in weight and high precision of the mirror surface.

[0040] In this regard, in this embodiment, as shown in Fig. 2, the back surface 1b of the mirror surface 1 has a flat shape, so that the mirror surface 1 alone can be mirror-polished, making it easy to obtain a highly accurate mirror surface. In this embodiment, the back surface 1b of the mirror surface 1, which has already been thinned and mirror-polished, is reinforced with a lightweight, highly rigid foam core 3a and further reinforced with a honeycomb core 3b having a low core density, thereby reducing the weight of the galvanometer mirror 100 and preventing a decrease in the accuracy of the mirror surface due to deformation of the mirror surface 1. In other words, this embodiment can achieve both weight reduction and high accuracy of the mirror surface.

[0041] 1, the galvanometer mirror 100 has a sandwich structure in which a lightweight and highly rigid foam core 3a, an ultra-lightweight honeycomb core 3b made of carbon fiber reinforced plastic, and a mirror fixing portion 4 made of ceramics are sandwiched between a mirror surface 1 made of ceramics with a high specific modulus of elasticity and a reinforcing plate 2 made of carbon fiber reinforced plastic with a high specific modulus of elasticity. This structure makes it possible to obtain a galvanometer mirror 100 that can achieve a lightweight and highly accurate mirror surface while ensuring rigidity that makes it difficult to deform.

[0042] 1 is made of a material different from the core material 3, thereby making the physical properties discontinuous. As a result, strain generated when fixing the galvanometer mirror 100 to another member is less likely to be transmitted to the mirror surface 1 via the core material 3, reducing deterioration in the precision of the mirror surface of the mirror surface 1. Furthermore, a large bonding area can be secured between the mirror fixing part 4 and the core material 3, reducing strain generated at the boundary between the mirror fixing part 4 and the mirror surface 1 when the galvanometer mirror 100 is driven.

[0043] In this embodiment, as shown in Figure 1, the galvanometer mirror 100 can be manufactured by bonding and integrating the mirror surface 1, reinforcing plate 2, two types of core material 3, and mirror fixing portion 4. This eliminates the need for complex processing to reduce weight, and the galvanometer mirror 100 can be manufactured using simple processing and manufacturing processes. In particular, since the mirror surface 1 can be polished to a mirror finish by itself, the mirror polishing process can be achieved in a simple process, and a highly accurate mirror surface can be obtained.

[0044] In this embodiment, when the mirror surface 1 shown in FIG. 1 is a sapphire plate, a single-crystal silicon carbide wafer, or a single-crystal silicon wafer, a thinner and lighter mirror surface 1 can be obtained, and the precision of the mirror surface of the mirror surface 1 can be easily increased, compared to the conventional technique of obtaining the mirror surface 210 (see FIG. 9) by performing weight reduction processing and mirror polishing processing on bulk materials such as silicon carbide or beryllium.

[0045] In this embodiment, the adhesive layer 5 shown in FIG. 2 is a film adhesive, which can absorb minute misalignments of the adhesive surfaces of the components, thereby stabilizing the external dimensions of the components after bonding, and thereby providing a galvanometer mirror 100 with high dimensional accuracy.

[0046] Next, a modification of the galvanometer mirror 100 according to the first embodiment will be described.

[0047] Although the shape of the gripping portion 4a shown in Fig. 3 is rectangular in this embodiment, it may be, for example, columnar or cylindrical as shown in Fig. 13. Fig. 13 is a perspective view showing a galvanometer mirror 100 according to a first modification of the first embodiment. Note that Fig. 13 illustrates a state in which the galvanometer mirror 100 is turned upside down on the paper from the state shown in Fig. 3.

[0048] The XY cross-sectional shape of the galvanometer mirror 100 shown in Fig. 5 is trapezoidal in this embodiment, but if the overall thickness of the galvanometer mirror 100 is thin, for example, 5 mm or less, it may be rectangular, as shown in Fig. 14. Fig. 14 is a diagram showing the cross-sectional shape of the galvanometer mirror 100 according to Modification 2 of Embodiment 1, and corresponds to the cross-sectional view taken along line V-V in Fig. 4. The mirror fixing portion 4 is not shown in Fig. 14.

[0049] Next, the effects of the present disclosure will be further described using examples and comparative examples.

[0050] Example 1 The galvanometer mirror in Example 1 had a sandwich structure in which a foam core, a honeycomb core, and a mirror fixing portion were sandwiched between a mirror surface and a reinforcing plate. A silicon wafer was used for the mirror surface, which constituted the front surface of the galvanometer mirror. EVONIC's ROHACELL 110HP was used for the foam core. Ultracor's honeycomb UCF-137-3 / 8-10 was used for the honeycomb core. DIALEAD k63712 was used for the reinforcing plate, which constituted the rear surface of the galvanometer mirror. A CFRP plate molded with a fiber content of 60% and a fiber orientation of 0 / 90 degrees was used for DIALEAD k63712. A C / SiC material was used for the mirror fixing portion. Adjacent components were fixed together using a 100 μm-thick film adhesive, integrating the mirror surface, reinforcing plate, foam core, honeycomb core, and mirror fixing portion. The detailed dimensions of each member were set to be equivalent to the inertia of the galvanometer mirror according to the first comparative example.

[0051] (Comparative Example 1) The galvanometer mirror according to Comparative Example 1 was made of a single material. Specifically, the galvanometer mirror according to Comparative Example 1 was obtained by processing a sintered SiC material to reduce its weight and then polishing it to a mirror finish. The external shape of the galvanometer mirror according to Comparative Example 1 was the same as the shape shown in FIG. 9 . Detailed dimensions will be omitted.

[0052] (Comparative Example 2) The galvanometer mirror of Comparative Example 2 was configured by sandwiching only one type of core material, a honeycomb core, between two CFRP plates, one on the front and one on the back. The CFRP plates were made of the same material as the reinforcing plate of Example 1. The honeycomb core was made of the same material as the honeycomb core of Example 1, manufactured by Ultracor Corporation, honeycomb UCF-137-3 / 8-10. Adjacent members were fixed together using a 100 μm thick film adhesive, integrating the two CFRP plates and the honeycomb core. In Comparative Example 2, the thickness of the CFRP plates and the thickness of the honeycomb core were set so that the amount of deformation during operation of the galvanometer mirror was approximately the same as that of the galvanometer mirror of Comparative Example 1.

[0053] Comparative Example 3 The galvanometer mirror according to Comparative Example 3 had the same configuration as Example 1, except that the core material was made of only one type of foam core.

[0054] (Test Method) The weight, inertia, precision of the mirror surface, and deformation amount during driving (high rigidity: difficulty in deformation) were evaluated for the galvanometer mirrors of Example 1 and Comparative Examples 1 to 3. Regarding the deformation amount during driving, each galvanometer mirror was incorporated into a galvanometer scanner, and the deformation amount of the mirror surface of the galvanometer mirror was found by finite element analysis when the galvanometer scanner was driven at maximum acceleration.

[0055] Table 1 shows the evaluation results of the galvanometer mirrors according to Example 1 and Comparative Examples 1 to 3. In Table 1, the numerical value for each evaluation item is expressed as an index, with the numerical value for the galvanometer mirror of Comparative Example 1 being set at 100. The smaller the numerical value for each evaluation item, the better the characteristics of that evaluation item.

[0056]

[0057] As is clear from Table 1, when the rigidity of Comparative Example 2 was designed so that the deformation during actuation was equivalent to that of Comparative Example 1, the weight and inertia were reduced to less than 50% of those of Comparative Example 1, while the precision of the mirror surface was approximately 1.5 times that of Comparative Example 1. This is due to dimples occurring on the surface of the CFRP plate (see Figure 11). To eliminate the dimples, the thickness of the CFRP plate would need to be three to four times that of Comparative Example 2, but this would result in the weight and inertia being more than twice that of Comparative Example 1. Furthermore, even if the dimples were eliminated, the precision of the molded surface would be insufficient due to the effect of curing shrinkage of the resin during molding. Furthermore, because the molded surface is a mixture of two materials, resin and fiber, sufficient surface roughness could not be achieved even by mirror polishing the molded surface, making it impossible to achieve a mirror finish. One method of mirror-finishing the molding surface is to cover it with a single material and then polish it to a mirror finish, but this is not desirable because it increases the weight and inertia even more and can cause bimetallic deformation in the galvanometer mirror when metallizing is performed.

[0058] In Comparative Example 3, the rear surface of the Si wafer does not have a reinforcing structure, and the rear surface of the Si wafer is not subjected to weight reduction processing, so the mirror surface precision is better than in Comparative Example 1. Furthermore, Comparative Example 3 has a weight that is less than Comparative Example 1, but the overall thickness of the galvanometer mirror is thicker than in Comparative Example 1, so the inertia is greater than in Comparative Example 1. Furthermore, the rigidity of the foam core is lower than that of the honeycomb core, and the rigidity of the core as a whole is insufficient, so the amount of deformation during operation is greater than in Comparative Example 1. To reduce the amount of deformation during operation, the foam core needs to be thicker, but this results in a weight greater than in Comparative Example 1. Furthermore, the inertia also increases, which is undesirable because the driving speed of the galvanometer mirror decreases when driven with the same galvanometer motor.

[0059] When Example 1 was designed to have the same inertia as Comparative Example 1, the weight, precision of the mirror surface, and deformation amount during driving were all reduced compared to Comparative Example 1. In other words, when the galvanometer mirror of Example 1 is mounted on a laser processing machine or the like, it is possible to achieve high precision and high speed processing.

[0060] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, and parts of the configurations may be omitted or modified without departing from the spirit of the invention.

[0061] Various aspects of the present disclosure are summarized below as appendices.

[0062] (Note 1) A galvanometer mirror comprising: a mirror surface having a front surface that serves as a mirror surface and a planar rear surface facing away from the front surface; a reinforcing plate provided on the rear side of the mirror surface at a distance from the rear surface; multiple types of core materials including a foam core and a honeycomb core that are sandwiched and disposed between the mirror surface and the reinforcing plate and fixed to the rear surface of the mirror surface; and a mirror fixing part that is sandwiched and disposed between the mirror surface and the reinforcing plate and is formed of a material different from the core material, for fixing the galvanometer mirror to another member; wherein adjacent members among the mirror surface, the reinforcing plate, the core material, and the mirror fixing part are fixed to each other via an adhesive layer, and the mirror surface, the reinforcing plate, the core material, and the mirror fixing part are integrated together. (Supplementary Note 2) The galvanometer mirror according to Supplementary Note 1, characterized in that the mirror surface is made of a ceramic plate of any one of alumina, sapphire, boron carbide, silicon nitride, aluminum nitride, silicon carbide, B4C-TiB2, and beryllium, or a wafer of any one of single crystal silicon carbide and single crystal silicon, or a single crystal silicon wafer. (Supplementary Note 3) The types of core material are two types, the foam core and the honeycomb core, and the foam core has a bulk density of 0.4 g / cm3. 3 and the foam core has an elastic modulus of 0.1 GPa or more, and the honeycomb core has a bulk density of 0.2 g / cm 3 The galvanometer mirror according to claim 1 or 2, characterized in that the specific elastic modulus of the honeycomb core is less than 10. (Supplementary Note 4) The material of the reinforcing plate is carbon fiber reinforced plastic, and the bulk density of the reinforcing plate is 1.85 g / cm3 and the reinforcing plate has a modulus of elasticity of 120 GPa or more. (Appendix 5) The galvanometer mirror according to any one of Appendices 1 to 4, wherein the material of the mirror fixing portion is a ceramic having a specific modulus of elasticity of 100 or more. (Supplementary Note 6) A method for manufacturing a galvanometer mirror comprising: a mirror surface having a front surface that serves as a mirror surface and a planar rear surface facing away from the front surface; a reinforcing plate provided on the rear side of the mirror surface at a distance from the rear surface; multiple types of core materials including a foam core and a honeycomb core that are sandwiched and disposed between the mirror surface and the reinforcing plate and fixed to the rear surface of the mirror surface; and a mirror fixing part that is sandwiched and disposed between the mirror surface and the reinforcing plate and is formed of a material different from the core material, for fixing the galvanometer mirror to another member, comprising: a fixing step of fixing adjacent members among the mirror surface, the reinforcing plate, the core material, and the mirror fixing part with an adhesive layer to integrate the mirror surface, the reinforcing plate, the core material, and the mirror fixing part; and a coating step of, after the fixing step, depositing a metal material on the mirror surface of the mirror surface or coating the mirror surface by sputtering to form a coating on the mirror surface. and a coating step of further coating the coating on the mirror surface with a dielectric multilayer coating. (Appendix 7) A method for manufacturing a galvanometer mirror according to Appendix 6, characterized in that it includes a mirror polishing step of mirror-polishing the front surface of the mirror surface before the fixing step. (Appendix 8) A method for manufacturing a galvanometer mirror according to Appendix 6 or 7, characterized in that the adhesive layer is a film-like adhesive made of a resin sheet.

[0063] 1,210 mirror surface, 1a, 220 front surface, 1b, 230 back surface, 1c single crystal ingot, 1d wafer, 1e trimming member, 2 reinforcement plate, 3 core material, 3a foam core, 3b, 320 honeycomb core, 3c, 3d notch portion, 4 mirror fixing portion, 4a grip portion, 5 adhesive layer, 5a first adhesive layer, 5b second adhesive layer, 5c third adhesive layer, 5d exposed surface, 100, 200, 300 galvanometer mirror, 240 rib, 250 spine structure portion, 260 rib reinforcement portion, 270, 330 dimple, 310 surface plate.

Claims

1. A galvanometer mirror comprising: a mirror surface having a front surface that serves as a mirror surface and a flat rear surface facing away from the front surface; a reinforcing plate provided on the rear side of the mirror surface and spaced apart from the rear surface; multiple types of core materials including a foam core and a honeycomb core that are sandwiched and disposed between the mirror surface and the reinforcing plate and fixed to the rear surface of the mirror surface; and a mirror fixing part that is sandwiched and disposed between the mirror surface and the reinforcing plate and is made of a material different from the core material, for fixing the galvanometer mirror to another member; wherein adjacent members of the mirror surface, the reinforcing plate, the core material, and the mirror fixing part are fixed to each other via an adhesive layer, and the mirror surface, the reinforcing plate, the core material, and the mirror fixing part are integrated together.

2. The galvanometer mirror according to claim 1, wherein the mirror surface is made of a ceramic plate selected from the group consisting of alumina, sapphire, boron carbide, silicon nitride, aluminum nitride, silicon carbide, B4C-TiB2, and beryllium, or a wafer selected from the group consisting of single-crystal silicon carbide, single-crystal silicon, or single-crystal silicon wafer.

3. The core material is of two types, the foam core and the honeycomb core, and the foam core has a bulk density of 0.4 g / cm 3 and the foam core has an elastic modulus of 0.1 GPa or more, and the honeycomb core has a bulk density of 0.2 g / cm 3 3. The galvanometer mirror according to claim 1, wherein the honeycomb core has a specific elastic modulus of 10 or more.

4. The material of the reinforcing plate is carbon fiber reinforced plastic, and the bulk density of the reinforcing plate is 1.85 g / cm 3 4. The galvanometer mirror according to claim 1, wherein the reinforcing plate has an elastic modulus of 120 GPa or more.

5. A galvanometer mirror according to any one of claims 1 to 4, characterized in that the material of the mirror fixing portion is ceramics having a specific modulus of elasticity of 100 or more.

6. A method for manufacturing a galvanometer mirror comprising: a mirror surface having a front surface that serves as a mirror surface and a flat rear surface facing away from the front surface; a reinforcing plate provided on the rear side of the mirror surface and spaced apart from the rear surface; multiple types of core materials including a foam core and a honeycomb core that are sandwiched and disposed between the mirror surface and the reinforcing plate and fixed to the rear surface of the mirror surface; and a mirror fixing part that is sandwiched and disposed between the mirror surface and the reinforcing plate and is formed of a material different from the core material and is used to fix the galvanometer mirror to another member, the method comprising: a fixing step of fixing adjacent members among the mirror surface, the reinforcing plate, the core material, and the mirror fixing part with an adhesive layer to integrate the mirror surface, the reinforcing plate, the core material, and the mirror fixing part; and a coating step of, after the fixing step, forming a coating on the mirror surface by evaporating a metal material onto the mirror surface of the mirror surface or by sputtering the mirror surface. a coating step of further coating the coating on the mirror surface with a dielectric multilayer coating.

7. The method for manufacturing a galvanometer mirror according to claim 6, further comprising a mirror polishing step for mirror-polishing the front surface of the mirror surface before the fixing step.

8. The method for manufacturing a galvanometer mirror according to claim 6 or 7, wherein the adhesive layer is a film-like adhesive made of a resin sheet.

Images