JP2012203268A - Mirror and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mirror which can be made large-sized as well as light-weight while satisfying requirements of accuracy, and a manufacturing method thereof.SOLUTION: A tabular base material 11 forming a reflecting film 14 is formed by softening and bending a glass plate by heating and has a surface 11a being an optical surface subjected to surface finish treatment including polishing, so that optical accuracy of a mirror body 10 can be improved. Namely, the surface (optical surface) 11a of the base material 11 is made optically accurate because the surface 11a is bent by heating to become a curved surface having a desired curvature and microscopic irregularities and macroscopic irregularities leading to accuracy degradation are removed from the surface 11a by the surface finish treatment such as grinding and polishing. The reflecting film 14 is formed on the surface 11a to obtain the mirror body 10 which has a reflecting surface of high accuracy though being like a bent plate.

Description

  The present invention relates to a lightweight mirror that can be enlarged while ensuring accuracy, and a method for manufacturing the same.

  As a manufacturing method of the reflecting mirror, a glass plate is disposed at the lower end of a molding die having a concave surface on the lower side, and the glass plate is softened by heating, and exhausted from a vent hole formed in the center of the molding die, thereby producing glass. There exists what makes a board the shape which followed the concave surface of the shaping | molding die (refer patent document 1). In this method, the glass plate and the mold are in close contact with each other, and an air pocket is unlikely to remain between them, so that the concave shape can be made relatively accurate.

  However, since the glass plate is thermally deformed, it is not easy to obtain a desired accurate optical surface even if the glass plate has an originally polished surface. That is, even if the back surface of the glass plate has a precise curvature, the surface may not have a precise curvature due to a change in the thickness of the glass plate. Moreover, there is a possibility that the optical surface deteriorates as the glass plate is heated or deformed.

JP 2008-7375 A

  The present invention has been made in view of the above problems of the background art, and an object of the present invention is to provide a mirror and a method for manufacturing the same that satisfy both requirements for accuracy and can be both increased in size and reduced in weight. .

  In order to solve the above problems, the mirror according to the present invention is formed by (a) softening and bending a glass plate material by heating, and an optical surface subjected to a surface finishing treatment including polishing, A plate-like base material having a back surface facing the optical surface; and (b) a reflective film formed on the optical surface of the base material.

  In the mirror, since the plate-like base material forming the reflective film is formed by softening and curving a glass plate material by heating, and has an optical surface subjected to surface finishing treatment including polishing, The optical accuracy of the mirror can be increased. In other words, the optical surface of the base material is not only a curved surface having a desired curvature by bending using heating, but also microscopic unevenness and macroscopic unevenness that lead to deterioration of accuracy by surface finishing treatment are removed. And optically precise. Therefore, by forming a reflective film on this optical surface, it is possible to obtain a mirror having a highly accurate reflective surface while having a curved plate shape. The above mirror uses a plate-like base material, and it is easy to ensure relatively light weight even if it is enlarged.

  In a specific aspect of the present invention, in the mirror, at least a part of the outer periphery of the base material is removed by cutting. Thereby, the outline shape of a reflective surface can be set easily.

  In another aspect of the present invention, the base material is supported by a plurality of supports bonded to the central region on the back surface side. Thereby, a base material can be stably supported with few distortions.

  In still another aspect of the present invention, the plurality of supports are glass cylindrical members, and are bonded to the central region at one end of the cylindrical members. In this case, the base material of the mirror body and the cylindrical member of the support are formed of the same material, and the stability against temperature can be enhanced while ensuring the strength of the support.

  In still another aspect of the present invention, a plurality of supports are fixed on a support base including a tilt adjusting device. In this case, it becomes easy to install the mirror and adjust the posture.

  Moreover, in order to solve the said subject, the manufacturing method of the mirror which concerns on this invention consists of (a) the process which prepares the glass-made board | plate material, and (b) heating a board | plate material on the transcription | transfer type stand which has a transfer surface in the upper part. A step of forming a precursor having a curved surface by softening and bending, and (c) having an optical surface by fixing the precursor on a finishing table and performing a surface finishing process including polishing on the curved surface. A step of forming a plate-shaped base material, and (d) a step of forming a reflective film on the optical surface of the base material.

  In the above mirror manufacturing method, since the precursor is fixed on the finishing table and the curved surface is subjected to surface finishing processing including polishing, a plate-like base material having an optical surface is formed. Accuracy can be improved. That is, the optical surface of the base material is processed from a curved surface formed by softening a plate material by heating, and has a curved surface having a desired curvature. Furthermore, the optical surface of the base material is optically precise by removing irregularities that lead to accuracy degradation by the surface finishing process. Therefore, by forming a reflective film on this optical surface, it is possible to obtain a mirror having a highly accurate reflective surface while having a curved plate shape. The above mirror uses a plate-shaped base material, and it is easy to ensure relatively light weight even if it is enlarged.

  In a specific aspect of the present invention, in the above mirror manufacturing method, the reflective film is formed of an aluminum vapor deposition layer. Thereby, an inexpensive mirror with high reflectance can be provided.

  In another aspect of the present invention, the reflective film has a protective coat covering the reflective layer on the substrate. In this case, the durability of the reflective film and the mirror can be increased by protecting the reflective layer.

  In still another aspect of the present invention, the glass plate is flat glass having a uniform thickness. In this case, a high-precision mirror can be provided relatively easily by using an inexpensive flat glass that is industrially mass-produced.

  In still another aspect of the present invention, the transfer mold base has a diatomaceous earth transfer portion on which a transfer surface is formed. By producing the transfer mold table using diatomaceous earth, the durability of the transfer mold table, that is, the shape stability at high temperatures, can be improved. Moreover, since the diatomaceous earth molded product is easy to create a shape by cutting and is inexpensive, it is possible to increase the workability of the transfer mold base and to reduce the cost.

  In still another aspect of the present invention, the finishing table has a support portion made of gypsum that supports the back surface of the precursor. By making a finishing table using gypsum, it becomes easy to follow the curved precursor on the support surface of the finishing table, and the support of the precursor is stabilized during the surface finishing process including polishing depending on the strength of the gypsum. it can.

  In still another aspect of the present invention, in the step of forming the precursor, the back surface of the heated plate is sucked to the transfer surface of the transfer mold base. In this case, the transfer surface formed on the transfer mold table can be reliably transferred to the glass plate material, and the curved surface of the precursor has an accurate curvature, so that the surface finishing process including polishing is quick. Therefore, it is easy to improve the accuracy of the obtained mirror.

(A) is a figure explaining the side cross section of the mirror of 1st Embodiment, (B) is a side view of a mirror, (C) is a back view of a mirror. (A) is a figure explaining the cross-sectional structure of a mirror main body, (B) is a back view of a mirror main body, (C) is a perspective view explaining a support body, (D) is It is a partial expanded sectional view explaining the modification of a mirror main body. (A) is a conceptual side view explaining the thermoforming apparatus for manufacturing a precursor, (B) is a top view of the transfer part in a thermoforming apparatus. It is a figure explaining the method of processing or creating the transfer surface of a transfer part. (A)-(C) are the side views explaining the manufacturing process of a precursor in steps. It is a conceptual side view explaining the finishing apparatus for manufacturing a base material. It is a conceptual top view explaining a finishing apparatus. It is a figure explaining the side cross section of the mirror of 2nd Embodiment. It is a figure explaining the side cross section of the mirror of 3rd Embodiment. (A) And (B) is a figure explaining the modification of a mirror.

[First Embodiment]
Hereinafter, a mirror and a manufacturing method thereof according to a first embodiment of the present invention will be described with reference to the drawings.

  First, the structure of the mirror according to the first embodiment will be described with reference to FIGS. 1 (A) to 1 (C). The mirror 100 includes a mirror main body 10, a back surface support unit 20, and a support base 30.

  The mirror body 10 is made of a glass material, has a shallow dome-like outer shape or a thin partial spherical shell-like outer shape, has a circular outline in a plan view, and has an arcuate outline in a side view. The mirror body 10 has a size of, for example, a diameter of about 10 cm to 120 cm. The surface 10a of the mirror body 10 is a smooth reflecting surface that is, for example, a spherical surface, and the back surface 10b of the mirror body 10 is a spherical surface having substantially the same curvature along the surface 10a that is the reflecting surface. That is, the front surface 10a and the back surface 10b are opposed to each other at equal intervals, and the mirror body 10 has a substantially uniform thickness throughout.

  As shown in FIG. 2A, the mirror body 10 has a structure in which the surface 11 a of the base material 11 is covered with a reflective film 14. The reflective film 14 has a reflective layer 12 on the lower side and a protective coat 13 on the upper side. The base material 11 has a thickness of 5 mm to 30 mm, for example. The front surface 11 a of the base material 11 is a smooth optical surface, for example, a spherical surface, and the back surface 11 b of the base material 11 is the back surface 10 b of the mirror body 10. The surface 11a of the base material 11 is mirror-finished by polishing. The reflective layer 12 on the surface 11a is formed of a vapor deposition layer such as aluminum or silver, and has a uniform thickness of about 1500 to 3000 mm, for example. The protective coat 13 on the reflective layer 12 is formed of a thin film such as aluminum oxide or silicon oxide, for example, and has a uniform thickness of about 800 to 2300 when the reflection wavelength is 300 to 800 nm, for example.

  As illustrated in FIG. 2B, the back surface support unit 20 includes a plurality of support bodies 21. These supports 21 are bonded to the central area A0 of the back surface 10b of the mirror body 10 on the one hand and to the surface 30a of the support base 30 shown in FIG. In the illustrated example, three supports 21 are provided as components of the back surface support unit 20, and these supports 21 are arranged at equal intervals on the circumference around the optical axis OA of the mirror body 10. It is fixed. That is, the mirror body 10 is supported by the three supports 21 constituting the back surface support unit 20 at three points with a small amount of distortion and with a good balance.

  As shown in FIG. 2C, the support 21 is a cylindrical member formed of a glass material having a thermal expansion coefficient close to that of the base material 11, and has a size of about 10 mm in diameter and about several cm in length. Have. The upper end surface 21a of the support 21 is bonded to the back surface 10b of the mirror body 10 so as to fill the gap with an adhesive such as epoxy. The lower end surface 21b of the support body 21 and the surrounding side surface 21c are formed of a surface 30a of the support base 30 and a support protrusion 31 provided on the support base 30 so as to fill a gap with an adhesive such as epoxy. Glued to.

  As shown in FIG. 1A and the like, the support base 30 includes an upper plate 32, a lower plate 33, and a plurality of connecting members 34. The upper plate 32 is formed of a steel material such as stainless steel and has a plurality of support protrusions 31 protruding from the surface 30a. Each support protrusion 31 has a role of reinforcing the support of each support body 21 that constitutes the back surface support unit 20, and in particular, prevents each support body 21 from falling. The lower plate 33 is formed of a float plate glass or other glass material having a thermal expansion coefficient close to that of the base material 11 and having a relatively high toughness. Note that the upper plate 32 can also be formed of a material having a thermal expansion coefficient close to that of the base material 11, similarly to the lower plate 33. The connecting member 34 is an expansion / contraction mechanism including a spring 34 a and a screw 34 b and is formed at three locations between the upper plate 32 and the lower plate 33. The three connecting members 34 function as a tilt adjusting device 35, and by adjusting the lengths of the three connecting members 34 individually, the tilt adjustment of the upper plate 32 with respect to the lower plate 33 can be performed. The optical axis OA can be tilted in a desired direction at a desired tilt angle.

  In the above, the mirror main body 10 is a plate-like body obtained by processing plate glass, and can be relatively lightened. Furthermore, the surface 11a of the base material 11 is an optical surface formed by soft polishing, that is, a mirror surface, and the optical accuracy of the surface (reflection surface) 10a formed on the surface 11a is high. In a specific manufacturing example, the diameter of the mirror body 10 is 100 mm, and the thickness of the mirror body 10 is 10 mm. The produced mirror body 10 is capable of forming a light condensing spot of 0.1 mm or less, although it is slightly bent due to its own weight, and can form an image with a resolution (about 1 arc angle) comparable to that of the human naked eye. It was found that it can withstand optical use. The thickness of the mirror body 10 is set according to the application of the mirror 100 in consideration of an error due to bending due to its own weight.

  2D and the like, the outer peripheral portion 10d of the mirror body 10 can be covered with a protective member 15. The protection member 15 is formed of, for example, a flexible resin, and is formed over the entire circumference of the mirror body 10, for example. Such a protective member 15 can increase the strength of the mirror body 10 and prevent damage due to contact with other components and mechanisms.

  Hereinafter, a method for manufacturing the mirror 100 according to the first embodiment shown in FIG.

  First, with reference to FIG. 3 (A) and 3 (B), the thermoforming apparatus for manufacturing a precursor is demonstrated among the manufacturing processes of the mirror 100. FIG. The illustrated thermoforming apparatus 200 includes a transfer mold base 40, a heater 51, and an exhaust device 53.

  The transfer mold table 40 is obtained by placing a transfer unit 42 on a pedestal 41. The transfer part 42 is formed of diatomaceous earth. A transfer surface 42 a is formed in the upper part of the transfer part 42, and an exhaust vent 42 c is provided in the center of the transfer part 42. The transfer surface 42a is, for example, a concave spherical surface, and has a curvature corresponding to the front surface 10a or the back surface 10b of the mirror body 10 of the mirror 100 that is the final target.

  The transfer part 42 is formed by cutting and shaping a diatomaceous earth layer into a cylindrical shape and sintering it, for example, and forming a transfer surface 42a on the original. For example, as shown in FIG. 4, the transfer surface 42 a is formed by rotating a plate-like blade 49 around the axis AX. The lower end 49a of the blade 49 has a contour corresponding to the curvature on the diameter of the target optical surface. By gradually lowering the blade 49 while rotating around the axis AX, the surface layer 142a of the original pattern 142 is removed, so that the transfer portion 42 having the transfer surface 42a as a desired rotationally symmetric curved surface is formed. The blade 49 described above can be formed of a material that is sufficiently harder than diatomaceous earth, such as hard metal, glass, ceramics, and the like.

  When the transfer portion 42 is used repeatedly, the transfer surface 42a may be gradually worn. However, by using the blade 49 shown in FIG. 4, the shape accuracy of the transfer surface 42a can be easily restored to the original state. Can be restored.

  The heater 51 is disposed so as to surround the side portion and the upper portion of the transfer portion 42 from the periphery, and is accommodated in the furnace wall 58. A temperature sensor (not shown) is installed in the furnace wall 58, and the furnace temperature around the transfer section 42 can be adjusted by adjusting the amount of power supplied to the heater 51 while monitoring the temperature sensor. .

  The exhaust device 53 has a decompression device 53a disposed outside the furnace wall 58, and the decompression device 53a communicates with the vent hole 42c of the transfer mold base 40 via a pipe 53b and the like. When the decompression device 53a is operated, the air in the space SP formed between the transfer portion 42 of the transfer mold base 40 and the plate glass 91 is discharged to the decompression device 53a through the vent holes 42c and 41c and the pipe 53b. The space SP is depressurized. Thereby, the back surface 91 b of the plate glass 91 is sucked toward the transfer surface 42 a of the transfer unit 42.

  Hereinafter, a precursor manufacturing process using the thermoforming apparatus 200 illustrated in FIG. 3A will be described. First, as shown in FIG. 5A, a plate glass 91 is set on the transfer surface 42 a of the transfer unit 42. At this time, the plate glass 91 is supported by the transfer portion 42 at the outer peripheral portion 91p and disposed horizontally. The plate glass 91 is obtained by cutting a glass plate material such as commercially available white plate glass, blue plate glass, Pyrex glass (registered trademark), Kovar sealing glass or Kovar glass (borosilicate glass) into a circular shape, and a transfer surface 42a. For example, it is cut into a circle so as to conform to the above. In addition, plate glass is used in large quantities for building materials and the like, and those having a thickness of up to 10 mm can be obtained very inexpensively. Such a plate glass has a hardness that is convenient for grinding and polishing, and can be finished into a clean mirror surface. In addition, plate glass is very resistant to moisture and weathering and is characterized by excellent cost efficiency.

  Next, the heater 51 is operated to heat the transfer portion 42 and the plate glass 91 thereon, and raise the temperature of the plate glass 91 to a temperature slightly higher than the softening point (for example, 600 ° C. to 700 ° C.). At this time, the exhaust device 53 is operated to suck the back surface 91 b of the plate glass 91 to the transfer surface 42 a of the transfer unit 42. As a result, the plate glass 91 is gradually softened and curved so that the center protrudes downward due to its own weight or the like, and the transfer surface 42a of the transfer unit 42 contacts any part of the back surface 91b of the plate glass 91. When the heating is further continued, the plate glass 91 is deformed to a target shape, and the entire back surface 91b of the plate glass 91 is substantially in close contact with the transfer surface 42a (see FIG. 5B).

  Thereafter, the operation of the heater 51 is stopped and the plate glass 91 is cooled to cure the plate glass 91. Thereby, the precursor 191 of the mirror main body 10 shown in FIG.

  Thereafter, the precursor 191 is separated from the transfer portion 42 and taken out of the furnace (see FIG. 5C). The precursor 191 thus obtained becomes the base material 11 of the mirror body 10 and has an outer shape substantially equal to the outer shape of the base material 11. That is, the precursor 191 has a shallow dome shape or a thin partial spherical shell shape. The surface 191a of the precursor 191 is a concave surface having a curvature corresponding to the surface 10a of the mirror body 10, but the optical accuracy is low. That is, when compared with the surface 10a of the mirror body 10, a region where the curvature is deviated from the target value is locally formed in a macroscopic manner, and microscopically fine wrinkles, swells, etc. exist. Since it has a low specularity, even if it is mirror coated, the optical application is limited. The back surface 191b of the precursor 191 is a concave surface having a curvature following the transfer surface 42a of the transfer portion 42. The back surface 191b also has low optical accuracy, but does not require optical accuracy, and thus becomes the back surface 10b of the mirror body 10 without being processed as it is.

  With reference to FIG. 6, the finishing apparatus for manufacturing a base material in the manufacturing process of the mirror 100 will be described. The illustrated finishing apparatus 300 includes a finishing table 60, a processing dish 70, a processing dish driving device 81, a rotating mechanism 82, and a driving device 83.

  The finishing table 60 includes a base material portion 61 and a support portion 62. The base material portion 61 is made of, for example, cement, ceramic or the like, and has a support surface 61a on the top. The support surface 61a is a concave spherical surface that approximates the transfer surface 42a in the transfer portion 42, and has a curvature close to that of the precursor 191 shown in FIG. In addition, the outer periphery upper part of the base material part 61 is covered with the outer periphery ring 64 made from stainless steel, for example. The support portion 62 is formed in a layered manner on the support surface 61 a of the base material portion 61 and inside the outer peripheral ring 64. The support portion 62 is in close contact with the back surface 191b of the precursor 191 in a substantially entire region including the central region, and supports the precursor 191 from below. The support part 62 is made of gypsum, for example. Specifically, gypsum is applied on the support surface 61a of the base material portion 61, the precursor 191 is lowered onto the gypsum before the gypsum is cured, and the back surface 191b of the precursor 191 is gypsum so that bubbles do not enter. Adhere to. Thereafter, when the gypsum is cured, a support portion 62 having a shape that is sandwiched between the base material portion 61 and the precursor 191 and fits to both is formed. The support 62 is usually adjusted to an appropriate thickness of 10 mm or less, and has a thickness of 1 mm to 3 mm, for example. For the purpose of reinforcing the support portion 62, gypsum can be added so as to fill the gap and cover the surface at the outer edge portion of the precursor 191.

  The processing dish 70 is a member formed of a metal material such as iron, and includes a processing plate 71 and a side wall 72. The lower surface 71a of the processed plate 71 has a curvature corresponding to the surface 10a of the mirror body 10 of the mirror 100, which is the final object. On the upper surface 71b of the processing plate 71, a link receiver 73 connected to a processing plate driving device 81 to be described later is fixed. The side wall 72 is a cylindrical member welded to the outer periphery of the processed plate 71. The lower surface 71a of the processed plate 71 is a processed surface for grinding. However, by replacing the lower surface 71a of the processed plate 71 with a pitch or other polishing pad 75 attached thereto, a processed surface for polishing is obtained. be able to.

  The processing plate drive device 81 includes an elevating shaft 81a, a load member 81b, a pair of arms 81c and 81d, and an arm drive mechanism 81e. Here, the elevating shaft 81a has a spherical link member 81f at the lower end and a support portion 81g at the upper end. The link member 81f engages with the link receiver 73 of the processing dish 70 and allows the processing dish 70 to rotate and tilt while supporting the processing dish 70. The support part 81g supports the load member 81b in a replaceable manner. The load member 81b is supported on the support portion 81g of the elevating shaft 81a and biases the processing dish 70 downward, that is, in the −Z direction. By appropriately adjusting the weight of the load member 81b, the pressure for pressing the processing plate 70 against the surface 191a of the precursor 191 can be adjusted. The pair of arms 81c and 81d has a bearing 81j on the tip side, is connected to the lifting shaft 81a and holds the lifting shaft 81a vertically.

  As shown in FIG. 7, the pair of arms 81c and 81d are coupled to a pair of discs 81m and 81n constituting the arm drive mechanism 81e on the base side. The disks 81m and 81n are rotated around the vertical axis by the motor 81r. By rotating the pair of discs 81m and 81n at a specific speed by the motor 81r, the pair of arms 81c and 81d rotate in the horizontal plane, that is, in the XY plane on the root side. As described above, by rotating the base side of the pair of arms 81c and 81d, the lifting shaft 81a supported at the tip of the arms 81c and 81d is moved radially and circumferentially above the finishing table 60. Moving. In other words, the processing plate 70 connected to the lower side of the lifting shaft 81a can be scanned or swung evenly on the surface 191a of the precursor 191 supported by the finishing table 60. The arms 81c and 81d can adjust the effective drive length and the radius of rotation on the base side by a link mechanism 81s provided on the disks 81m and 81n. The scanning or rocking pattern above can be changed.

  Returning to FIG. 6, the rotation mechanism 82 includes a rotation table 82a, a motor (not shown), and the like, and can rotate the finishing table 60 on the rotation table 82a at a desired speed.

  The drive device 83 controls the motor 81r (see FIG. 7) of the processing plate drive device 81 to operate the motor 81r at a desired timing and rotation speed.

  Hereinafter, the manufacturing process of the base material 11 using the finishing apparatus 300 shown in FIG. 6 etc. is demonstrated. First, as shown in FIG. 6, the precursor 191 is fixed on the finishing table 60 of the finishing device 300. At this time, the precursor 191 is supported from below by the support portion 62 and is itself a thin plate that is easily deformed by an external force, but is held on the finishing table 60 in a stable state.

  Next, the processing pan 70 for grinding is placed on the surface 191 a of the precursor 191, and the lifting shaft 81 a of the processing pan driving device 81 is connected. Thereafter, the finishing table 60 on the rotary table 82a is rotated by operating the rotation mechanism 82 via the drive unit 83 while supplying the grinding liquid containing the grinding sand. At the same time, the processing plate driving device 81 is operated via the driving device 83 to scan or swing the processing plate 70 on the precursor 191 in two dimensions. Thereby, the surface of the surface 191a of the precursor 191 is gradually ground, and the curvature of the surface 191a can be brought close to the intended curvature. At this time, by appropriately adjusting the weight of the load member 81b, excessive pressure is applied to the surface 191a of the precursor 191 so that excessive deformation does not occur. That is, the progress of grinding is made soft. In the grinding process, the smoothness of the surface 191a of the precursor 191 is gradually increased by gradually reducing the grinding sand contained in the grinding liquid. In the above grinding process, a surface shape test using a depth meter and an imaging camera is performed during grinding, and process management is performed to determine whether or not to proceed to the next process.

  Next, the processing dish 70 is exchanged from a grinding one to a polishing one. The polishing pad 75 provided on the processing plate 70 is obtained by, for example, coal tar being adhered to the lower surface 71a after being melted by heat and solidified by cooling. At the time of polishing, the finishing table 60 on the rotary table 82a is rotated by operating the rotating mechanism 82 via the driving device 83 while supplying a polishing liquid containing cerium oxide or the like. At the same time, the processing plate driving device 81 is operated via the driving device 83 to scan or swing the processing plate 70 on the precursor 191 in two dimensions. Thereby, the surface of the surface 191a of the precursor 191 is gradually but uniformly polished, and the surface 191a can be a mirror surface with a desired curvature. In the above polishing process, a surface shape test using a depth meter and an imaging camera is performed in the middle of polishing, and it is determined whether to end polishing or change the polishing pattern.

  The surface 191a of the precursor 191 that has been subjected to the above grinding and polishing is mirror-finished and becomes the base material 11 of the mirror body 10 shown in FIGS. 1 (A) and 2 (A). The base material 11 is removed from the finishing table 60 so as not to give excessive stress and cleaned.

  Hereinafter, the final manufacturing process of the mirror body 10 will be described. The base material 11 having the surface 11a as an optical surface ground and polished by the finishing apparatus 300 shown in FIG. 6 is cut in an unnecessary peripheral portion if necessary, set in a vapor deposition apparatus, and aluminum on the surface 11a. The made reflective layer 12 is formed. Thereafter, the base material 11 on which the reflective layer 12 is formed is anodized and has a protective coating 13 of aluminum oxide on the surface.

  In the mirror 100 according to the first embodiment described above, the plate-like base material 11 forming the reflective film 14 is formed by softening and bending the plate glass 91 by heating, and surface finishing including polishing. Since it has the surface 11a which is the optical surface which performed the process, the optical precision of the mirror main body 10 can be improved. That is, the surface (optical surface) 11a of the base material 11 is not only a curved surface having a desired curvature due to the curvature using heating, but is also microscopic which leads to deterioration in accuracy by surface finishing processing such as grinding and polishing. Unevenness and macroscopic unevenness are removed to make it optically precise. Therefore, by forming the reflection film 14 on the surface (optical surface) 11a, it is possible to obtain the mirror body 10 having a highly accurate reflection surface while being in a curved plate shape. In addition, the above mirror main body 10 utilizes the plate-shaped base material 11, and even if it enlarges, it is easy to ensure comparatively lightweight.

  The mirror 100 of this embodiment can be used as a reflecting mirror mounted on a reflective optical telescope, a condensing reflecting mirror mounted on a solar concentrating power generation device, and the like.

  In addition, in the mirror 100 of a specific manufacturing example, although it depends on the politeness of the polishing process, it was possible to realize a resolution of about 1 arc minute or less and to form a condensing spot of 0.1 mm or less. . In addition, the mirror 100 of the production example can achieve high light collection efficiency while being extremely inexpensive as compared with a thick mirror used for the same level of resolution as that of the naked eye such as astronomical observation.

[Second Embodiment]
Hereinafter, a mirror and a manufacturing method thereof according to the second embodiment will be described with reference to the drawings. The mirror and the like according to the second embodiment are obtained by partially changing the mirror and the like of the first embodiment, and parts that are not particularly described are the same as those of the first embodiment.

  As shown in FIG. 8, the support base 30 has a circular cover 37 that covers the mirror body 10 from behind. The cover 37 is formed of a thin plate-shaped metal material, and is fixed to the support base 30 at a central opening peripheral portion 37a. Further, the cover 37 has a guard 37b that is folded back to the surface 10a side of the mirror body 10 on the outer periphery. The cover 37 is not in contact with the mirror body 10 so as not to deteriorate the optical accuracy of the mirror body 10. By providing such a guard 37b, the durability of the mirror body 10 can be improved and the mirror 100 can be easily handled.

[Third Embodiment]
Hereinafter, a mirror and a manufacturing method thereof according to the third embodiment will be described with reference to the drawings. The mirror or the like according to the third embodiment is a partial modification of the mirror or the like of the first or second embodiment, and parts not specifically described are the same as those of the first or second embodiment.

  As shown in FIG. 9, the support base 30 has a circular cover 37 that covers the mirror body 10 from behind, and a filling member 38 made of foamable resin, fiber, or the like is provided between the cover 37 and the mirror body 10. Inserting. In this case, mechanical strength including resistance to vibration of the mirror 100 is increased.

  Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments, and can be implemented in various modes without departing from the gist thereof. Such modifications are also possible.

  The mirror body 10 is not limited to having a concave reflection surface, but can have a convex reflection surface by changing the transfer surface 42 a of the transfer unit 42. Further, the reflecting surface of the mirror body 10 is not limited to a spherical surface, but may be an aspherical surface by changing the transfer surface 42a. Furthermore, the outline of the reflecting surface of the mirror body 10 is not limited to a circle, and may be an ellipse, a polygon, or the like depending on the application or purpose. For example, the center of the mirror body 10 can be hollowed out to make a donut shape.

  In the above embodiment, the thickness of the mirror main body 10 is set to 5 mm to 30 mm. However, the thickness of the mirror main body 10 is set according to the application of the mirror 100 in consideration of an error due to bending due to its own weight. However, when forming the base material 11 of the mirror main body 10 from plate glass, it is desirable that the thickness conforms to a commercially available standard.

  In the above embodiment, three-point support is performed using three supports 21 as the back surface support unit 20, but the present invention is not limited to such back surface support unit 20. For example, when the deflection at the outer periphery of the mirror body 10 is large, the support 21 can be added not only to the central region A0 but also to the peripheral portion. Further, when the mirror main body 10 does not have a circular outline, the symmetry tends to be low and the deflection tends to increase. Therefore, it may be necessary to change the arrangement and number of the supports 21 to balance the support.

  Although the mirror 100 can be used alone, for example, as shown in FIG. 10A or 10B, a large mirror 100A can be configured by combining a plurality of mirrors 100.

  The transfer portion 42 is not limited to diatomaceous earth, but can be formed of carbon graphite, workable ceramics, or other inorganic materials. However, considering cost, heat resistance, workability, etc., diatomaceous earth is considered excellent at this time. .

  The support portion 62 is not limited to plaster but can be formed of polishing wax or the like. However, gypsum is easy to fit the shape of the back surface 191b of the precursor 191, easily matches the temperature at the time of curing and the temperature at the time of use, has a certain degree of strength, and can reduce costs. ,Are better.

  In the said embodiment, although the plate glass 91 is curved in the thermoforming apparatus 200, the plate glass 91 previously curved can also be curved further.

  In the above-described embodiment, the plate glass 91 is bent by its own weight in the thermoforming apparatus 200, but the plate glass 91 can be forcibly bent by a press or the like.

  In the above embodiment, the finishing apparatus 300 performs grinding and polishing, but the finishing apparatus 300 can also perform only polishing.

  The mirror 100 is not limited to a reflective optical telescope, but includes an imaging system of an in-vehicle image sensing device capable of photographing faint light at a high speed, a light source illumination system used for the purpose of guiding outside light indoors, a sudden accident, and the like. The present invention can be applied to various fields such as a monitoring optical system of a disaster or crisis monitoring apparatus, an observation optical system in a diagnostic observation apparatus such as medical treatment, a high-grade road mirror, and an illumination system of a stepper.

  The mirror 100 can be incorporated not only in the wavelength range of visible light but also in optical equipment used in the infrared and other wavelength ranges.

DESCRIPTION OF SYMBOLS 10 ... Mirror main body, 10a ... Front surface, 10b ... Back surface, 11 ... Base material, 11a ... Front surface, 11b ... Back surface, 12 ... Reflective layer, 13 ... Protective coat, 14 ... Reflective film, 15 ... Protective member, 20 ... Back surface support Unit: 21 ... Support, 30 ... Support base, 34 ... Connecting member, 35 ... Tilt adjusting device, 37 ... Cover, 38 ... Filling member, 40 ... Transfer mold base, 41 ... Pedestal, 42 ... Transfer section, 42a ... Transfer Surface, 42c ... Vent, 51 ... Heater, 53 ... Exhaust device, 58 ... Furnace wall, 60 ... Finishing table, 61 ... Base part, 62 ... Supporting part, 70 ... Processing plate, 82 ... Rotating mechanism, 91 ... Plate glass 100 ... Mirror, 191 ... Precursor, 200 ... Heat forming device, 300 ... Finishing device, A0 ... Central region, AX ... Axis, OA ... Optical axis

Claims (12)

A plate-shaped base material having an optical surface that has been subjected to a surface finishing treatment including polishing, and a back surface that faces the optical surface, and is formed by softening and bending a glass plate material by heating,
And a reflective film formed on the optical surface of the base material.   The mirror according to claim 1, wherein at least a part of the outer periphery of the base material is removed by cutting.   The mirror according to any one of claims 1 and 2, wherein the base material is supported by a plurality of supports bonded to a central region on the back surface side.   The mirror according to claim 3, wherein the plurality of supports are cylindrical members made of glass, and are bonded to the central region at one end of the cylindrical member.   The mirror according to any one of claims 1 to 4, wherein the plurality of supports are fixed on a support including a tilt adjusting device. A step of preparing a glass plate,
Forming a precursor having a curved surface by softening and curving the plate material by heating on a transfer mold base having a transfer surface on the top;
Forming a plate-shaped base material having an optical surface by fixing the precursor on a finishing table and performing a surface finishing treatment including polishing on the curved surface;
Forming a reflective film on the optical surface of the base material.   The said reflecting film is a manufacturing method of the mirror of Claim 6 currently formed with the vapor deposition layer made from aluminum.   The method of manufacturing a mirror according to claim 6, wherein the reflective film has a protective coat that covers the reflective layer on the substrate.   The method for manufacturing a mirror according to any one of claims 6 to 8, wherein the glass plate material is flat glass having a uniform thickness.   The method for manufacturing a mirror according to any one of claims 6 to 9, wherein the transfer mold stage has a transfer part made of diatomaceous earth on which the transfer surface is formed.   The said finishing base is a manufacturing method of the mirror as described in any one of Claim 6-9 which has the support part made from gypsum which supports the back surface of the said precursor.   The method of manufacturing a mirror according to any one of claims 6 to 11, wherein, in the step of forming the precursor, the back surface of the heated plate material is sucked to the transfer surface of the transfer mold base.

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