JP2005234344A

JP2005234344A - Mirror for astronomical telescope

Info

Publication number: JP2005234344A
Application number: JP2004044867A
Authority: JP
Inventors: Motohiro Umetsu; 基宏梅津; Mamoru Ishii; 守石井; Masako Kataoka; 昌子片岡; Masahito Iguchi; 真仁井口; Tomoyuki Sugaya; 智幸菅谷; Shiro Moriyama; 司郎森山; Shunichi Sasaki; 俊一佐々木; Masataka Hirose; 正孝廣瀬; Masanori Ie; 正則家; Masashi Otsubo; 政司大坪
Original assignee: NATIONAL ASTRONOMICAL OBSERVATORY OF JAPAN; National Astronomical Observatories of CAS; Nihon Ceratec Co Ltd; Taiheiyo Cement Corp
Current assignee: NATIONAL ASTRONOMICAL OBSERVATORY OF JAPAN; National Astronomical Observatories of CAS; Taiheiyo Cement Corp; NTK Ceratec Co Ltd
Priority date: 2004-02-20
Filing date: 2004-02-20
Publication date: 2005-09-02
Anticipated expiration: 2024-02-20
Also published as: JP4460325B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mirror for an astronomical telescope which is suitable to a large-sized astronomical telescope, has low thermal expansibility and high rigidity, and is further lightweight. <P>SOLUTION: The mirror 10 for the astronomical telescope has: reflecting members 11a and 11b which are made of ceramics with low thermal expansibility and have reflecting surfaces of ≤10 nm in surface roughness Ra for reflecting light; a reflecting film 15 which is formed on the reflecting surface of the plate member 11a; a core member 12 which is made of ceramics with low thermal expansibility and has a honeycomb structure; and join parts 13a and 13b which are made of ceramics with low thermal expansibility having a lower fusion temperature than the ceramics with the low thermal expansibility constituting the plate members 11a and 11b, and core member 12 and join the members so that the core member 12 is sandwiched between the plate members 11a and 11b. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、天体を観測する天体望遠鏡に設けられ、天体から届き、所定の集光手段によって集光された光を反射させる天体望遠鏡用ミラーに関する。 The present invention relates to an astronomical telescope mirror that is provided in an astronomical telescope for observing an astronomical object and reflects light that arrives from the astronomical object and is collected by a predetermined condensing means.

従来の天体望遠鏡用ミラーには、温度変化による熱変形を抑制するために、低熱膨張ガラス材料等の線膨張係数がゼロに近い材料が用いられている（例えば、特許文献１参照）。しかしながら、このような低熱膨張ガラス材料のヤング率は、高いもので１００ＧＰａ程度であり、十分な剛性を有しているとは言い難い。このため、低熱膨張性であり、かつ、より高剛性な天体望遠鏡用ミラーが求められている。 A conventional astronomical telescope mirror uses a material having a coefficient of linear expansion close to zero, such as a low thermal expansion glass material, in order to suppress thermal deformation due to temperature change (see, for example, Patent Document 1). However, such a low thermal expansion glass material has a high Young's modulus of about 100 GPa, and it is difficult to say that it has sufficient rigidity. For this reason, there is a need for an astronomical telescope mirror that has low thermal expansion and higher rigidity.

また、高倍率の視野により天体観測を行う場合、主反射鏡と呼ばれるミラー部材の大型化が必須である。しかし、ミラー部材が大型になり、その重量が増加した場合には、例えば、その剛性が不十分であると、共振固有値の低下を招き、ミラー部材を支持する支持体たる天体望遠鏡の主要な振動モードと共振して大荷重を受けやすいという問題等が生じる。このような観点から、大型のミラー部材では、高い剛性を有する材料を用いなければならない。 In addition, when performing astronomical observation with a high-power field of view, it is essential to increase the size of a mirror member called a main reflecting mirror. However, when the mirror member becomes large and its weight increases, for example, if its rigidity is insufficient, the resonance eigenvalue is lowered, and the main vibration of the astronomical telescope as a support that supports the mirror member. The problem that it is easy to receive a heavy load by resonating with the mode occurs. From this point of view, a large mirror member must use a material having high rigidity.

ここで、ミラー部材の軽量化を材料の観点から検討してみると、従来からミラー部材として用いられている低熱膨張ガラス材料では、その比重は２．２〜４．０と幅広く、比較的軽い材料もある。しかし、比重の小さい材料を用いても、中実無垢体のミラー部材では軽量化の実効を図ることは困難である。 Here, when the weight reduction of the mirror member is examined from the viewpoint of the material, the specific gravity of the low thermal expansion glass material conventionally used as the mirror member is as wide as 2.2 to 4.0 and is relatively light. There are also materials. However, even if a material with a small specific gravity is used, it is difficult to achieve a light weight with a solid solid mirror member.

これに対して、ミラー部材の軽量化を構造の観点から検討してみると、まず、その方法の１つとして、その内部を中空構造にすることが考えられる。しかし、ガラス材料を機械加工で中空構造にすることは非常に困難である。また、別の方法として、溝を設けたガラス部材に反射面を有する蓋部材を接合する方法が考えられるが、十分な母材強度および接合強度を満足するガラス材料を見いだすに至っていない。さらに別の方法として、反射面を有する部材を軽量な基台に接着または機械的に固定する方法も考えられるが、この場合には、反射部材と基台とで異なる材料が用いられることとなるために、これらの間の熱膨張差により、温度変化に対して寸法変化や歪みが生じるという問題が生ずる。
特開２００３−１８５８１１号公報 On the other hand, when considering reducing the weight of the mirror member from the viewpoint of structure, it is conceivable that the interior of the mirror member has a hollow structure as one of the methods. However, it is very difficult to make the glass material into a hollow structure by machining. As another method, a method of joining a lid member having a reflecting surface to a glass member provided with a groove is conceivable, but a glass material satisfying sufficient base material strength and joining strength has not been found. As another method, a method of bonding or mechanically fixing a member having a reflecting surface to a lightweight base is also conceivable, but in this case, different materials are used for the reflecting member and the base. For this reason, there arises a problem that a dimensional change or distortion occurs due to a temperature change due to a difference in thermal expansion between them.
JP 2003-185811 A

本発明はこのような事情に鑑みてなされたものであり、低熱膨張性であり、かつ、高剛性な材料からなる天体望遠鏡用ミラーを提供することを目的とする。また、本発明は、大型の天体望遠鏡用ミラーに適した、低熱膨張性かつ高剛性であり、さらに軽量な天体望遠鏡用ミラーを提供することを目的とする。 The present invention has been made in view of such circumstances, and an object thereof is to provide an astronomical telescope mirror made of a material having low thermal expansion and high rigidity. It is another object of the present invention to provide an astronomical telescope mirror that is suitable for a large astronomical telescope mirror, has low thermal expansion, is highly rigid, and is lightweight.

本発明の第１の観点によれば、天体望遠鏡に設けられ、天体から届き集光された光を反射させる天体望遠鏡用ミラーであって、
前記光を反射するための表面粗さがＲａで１０ｎｍ以下の反射面を備えた低熱膨張セラミックスからなるミラー部材と、
前記ミラー部材の反射面に設けられた所定の反射膜と、
を有することを特徴とする天体望遠鏡用ミラー、が提供される。 According to a first aspect of the present invention, there is provided an astronomical telescope mirror that is provided in an astronomical telescope and reflects light collected from the astronomical object and collected.
A mirror member made of a low thermal expansion ceramic having a reflective surface with a surface roughness Ra of 10 nm or less for reflecting the light;
A predetermined reflective film provided on the reflective surface of the mirror member;
An astronomical telescope mirror characterized by comprising:

この天体望遠鏡用ミラーを構成するミラー部材の−１０〜１０℃における平均の熱膨張係数は、−１×１０^−６〜１×１０^−６／℃の範囲にあることが好ましい。また、ミラー部材を構成する低熱膨張セラミックスとしては、それぞれ、リチウムアルミノシリケート、リン酸ジルコニウムカリウム、コーディエライトから選ばれる１種以上の第１の材料と、炭化珪素、窒化珪素、サイアロン、アルミナ、ジルコニア、ムライト、ジルコン、窒化アルミニウム、ケイ酸カルシウム、炭化ホウ素から選ばれる１種以上の第２の材料とを複合してなる複合材料を用いることが好ましい。 The average thermal expansion coefficient at −10 to 10 ° C. of the mirror member constituting this astronomical telescope mirror is preferably in the range of −1 × 10 ⁻⁶ to 1 × 10 ⁻⁶ / ° C. Moreover, as the low thermal expansion ceramics constituting the mirror member, one or more first materials selected from lithium aluminosilicate, potassium zirconium phosphate, and cordierite, silicon carbide, silicon nitride, sialon, alumina, It is preferable to use a composite material formed by combining at least one second material selected from zirconia, mullite, zircon, aluminum nitride, calcium silicate, and boron carbide.

本発明の第２の観点によれば、天体望遠鏡に設けられ、天体から届き集光された光を反射させる天体望遠鏡用ミラーであって、
前記光を反射するための表面粗さがＲａで１０ｎｍ以下の反射面を備えた低熱膨張セラミックスからなる板部材と、
前記板部材の反射面に設けられた所定の反射膜と、
低熱膨張セラミックスからなり、前記板部材と接合されて前記板部材を保持するコア部材と、
前記板部材と前記コア部材とを接合する、前記板部材および前記コア部材を構成する低熱膨張セラミックスよりも溶融温度の低い低熱膨張セラミックスからなる接合部と、
を有することを特徴とする天体望遠鏡用ミラー、が提供される。 According to a second aspect of the present invention, there is provided an astronomical telescope mirror which is provided in an astronomical telescope and reflects light collected from the astronomical object and collected.
A plate member made of low thermal expansion ceramics having a reflective surface with a surface roughness Ra of 10 nm or less for reflecting the light;
A predetermined reflective film provided on the reflective surface of the plate member;
A core member made of low thermal expansion ceramics and bonded to the plate member to hold the plate member;
Joining the plate member and the core member, a joint made of a low thermal expansion ceramic having a lower melting temperature than the low thermal expansion ceramic constituting the plate member and the core member;
An astronomical telescope mirror characterized by comprising:

この第２の観点に係る天体望遠鏡用ミラーを構成する板部材とコア部材には、第１の観点に係る天体望遠鏡用ミラーのミラー部材を構成する低熱膨張性セラミックスと同じものが好適に用いられる。 As the plate member and the core member constituting the astronomical telescope mirror according to the second aspect, the same low thermal expansion ceramic as that constituting the mirror member of the astronomical telescope mirror according to the first aspect is suitably used. .

また、第２の観点に係る天体望遠鏡用ミラーにおいては、板部材およびコア部材の−１０〜１０℃における平均の熱膨張係数と、接合部の−１０〜１０℃における平均の熱膨張係数との差は、±０．１×１０^−６／℃の範囲内であることが好ましい。これにより接合処理時における熱応力破壊や接着強度低下を抑制することができる。 In the astronomical telescope mirror according to the second aspect, the average thermal expansion coefficient of the plate member and the core member at −10 to 10 ° C. and the average thermal expansion coefficient of the joint at −10 to 10 ° C. The difference is preferably within a range of ± 0.1 × 10 ⁻⁶ / ° C. As a result, it is possible to suppress thermal stress fracture and adhesive strength reduction during the bonding process.

また、コア部材としてはハニカム構造体が好適に用いられ、この場合には、２枚の板部材を準備し、ハニカム構造体の上下開口面にそれぞれ板部材を接合したサンドイッチ構造とすることが好ましく、いずれか一方の板部材の表面を反射面とすればよい。また、コア部材は有底上面開口型のリブ構造体であってもよく、この場合には、リブ構造体の開口面に板部材を接合した構成とすることが好ましい。 Further, a honeycomb structure is preferably used as the core member. In this case, it is preferable to prepare a sandwich structure in which two plate members are prepared and the plate members are joined to the upper and lower opening surfaces of the honeycomb structure, respectively. The surface of any one of the plate members may be a reflective surface. Further, the core member may be a bottomed top opening type rib structure, and in this case, it is preferable that the plate member be joined to the opening surface of the rib structure.

本発明によれば、低熱膨張性かつ高剛性の天体望遠鏡用ミラーを得ることができる。また、コア部材としてハニカム構造体またはリブ構造体を用いることにより、軽量かつ高剛性な大型の天体望遠鏡用ミラーを実現することができる。 According to the present invention, an astronomical telescope mirror having low thermal expansion and high rigidity can be obtained. In addition, by using a honeycomb structure or a rib structure as the core member, a large and lightweight astronomical telescope mirror can be realized.

以下、本発明の実施の形態について図面を参照しながら説明する。図１は本発明に係る天体望遠鏡用ミラー１（以下「ミラー１」と記す）の概略断面図である。ミラー１は、光を反射するための反射面５を備えた盤状のミラー部材２と、この反射面５に設けられた反射膜３とから構成されている。ミラー部材２の反射面５の表面粗さは、光を高い反射率で反射することができるように、Ｒａで１０ｎｍ以下となっている。反射膜３としては、例えば、金属膜と誘電体膜を交互に積層された膜が挙げられる。なお、図１では、反射膜３を明示しているが、その厚さは、ミラー部材２の厚さと比較して非常に薄いものである。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of an astronomical telescope mirror 1 (hereinafter referred to as “mirror 1”) according to the present invention. The mirror 1 includes a disk-shaped mirror member 2 having a reflecting surface 5 for reflecting light, and a reflecting film 3 provided on the reflecting surface 5. The surface roughness of the reflecting surface 5 of the mirror member 2 is 10 nm or less in terms of Ra so that light can be reflected with high reflectivity. Examples of the reflective film 3 include a film in which metal films and dielectric films are alternately stacked. In FIG. 1, the reflective film 3 is clearly shown, but its thickness is very thin compared to the thickness of the mirror member 2.

ミラー部材２は低熱膨張性セラミックスからなり、その−１０〜１０℃における平均の熱膨張係数は、−１×１０^−６〜１×１０^−６／℃の範囲にあることが好ましい。これにより、ミラー１の使用環境下における形状変化を抑制し、高い精度での観測が可能となる。 The mirror member 2 is made of low thermal expansion ceramics, and the average thermal expansion coefficient at −10 to 10 ° C. is preferably in the range of −1 × 10 ⁻⁶ to 1 × 10 ⁻⁶ / ° C. Thereby, the shape change in the use environment of the mirror 1 is suppressed, and observation with high accuracy is possible.

このような熱膨張係数を有するセラミックス材料としては、リチウムアルミノシリケート、リン酸ジルコニウムカリウム、コーディエライトから選ばれる１種以上の第１の材料と、炭化珪素、窒化珪素、サイアロン、アルミナ、ジルコニア、ムライト、ジルコン、窒化アルミニウム、ケイ酸カルシウム、炭化ホウ素から選ばれる１種以上の第２の材料とを複合してなる複合材料が挙げられる。 As the ceramic material having such a thermal expansion coefficient, one or more first materials selected from lithium aluminosilicate, potassium zirconium phosphate, cordierite, silicon carbide, silicon nitride, sialon, alumina, zirconia, Examples thereof include a composite material formed by combining one or more second materials selected from mullite, zircon, aluminum nitride, calcium silicate, and boron carbide.

例えば、ミラー部材２として、リチウムアルミノシリケートの１つで負の熱膨張係数を有するβ−ユークリプタイト（β−Ｅｕ）と、正の熱膨張係数を有する炭化珪素（ＳｉＣ）とを、それぞれβ−Ｅｕ：ＳｉＣ＝６５〜８５ｍａｓｓ％：１５〜３５ｍａｓｓ％で配合した材料を用いる。このように、正の熱膨張係数を有する材料と負の熱膨張係数を有する材料との配合割合を変化させることにより、要求される熱膨張係数を有する材料を調製することができる。 For example, as the mirror member 2, β-eucryptite (β-Eu), which is one of lithium aluminosilicates and having a negative thermal expansion coefficient, and silicon carbide (SiC) having a positive thermal expansion coefficient are respectively β -Eu: SiC = 65 to 85 mass%: A material blended at 15 to 35 mass% is used. Thus, the material which has a required thermal expansion coefficient can be prepared by changing the mixture ratio of the material which has a positive thermal expansion coefficient, and the material which has a negative thermal expansion coefficient.

従来から天体望遠鏡用ミラーに用いられているガラス材料のヤング率は８０〜１２０ＧＰａ程度であるが、上記複合材料のヤング率は１２０〜１６０ＧＰａと高いために、このような複合材料を用いることにより、従来よりも高剛性な天体望遠鏡用ミラーを得ることができる。 Conventionally, the Young's modulus of the glass material used for the astronomical telescope mirror is about 80 to 120 GPa, but the Young's modulus of the composite material is as high as 120 to 160 GPa. By using such a composite material, It is possible to obtain an astronomical telescope mirror having higher rigidity than conventional ones.

ミラー部材２は、一般的なセラミックス焼結体の製造方法、例えば、粉末調製、プレス成形、焼成、切削・研削、研磨加工という工程を経ることによって得ることができる。ミラー１は、ミラー部材２の研磨面（反射面５）に所定の方法により反射膜３を形成すればよい。 The mirror member 2 can be obtained by a general method of manufacturing a ceramic sintered body, for example, through steps of powder preparation, press molding, firing, cutting / grinding, and polishing. In the mirror 1, the reflective film 3 may be formed on the polished surface (reflective surface 5) of the mirror member 2 by a predetermined method.

このミラー１においては、ミラー部材２が無垢構造体であるために、ミラー１を天体望遠鏡本体の支持体に搭載した場合に、支持体の主要振動モードと共振する問題や、支持体が振動荷重に耐えられなくなる問題等を回避することができる重量となるように、その大きさを設定することが望まれる。 In this mirror 1, since the mirror member 2 is a solid structure, when the mirror 1 is mounted on the support of the astronomical telescope main body, the problem of resonating with the main vibration mode of the support, It is desirable to set the size so that the weight can be avoided so that the problem of being unable to withstand the temperature can be avoided.

次に、ミラー１を、その高い剛性を維持しながら軽量化させた、本発明に係る別の天体望遠鏡用ミラーについて説明する。
図２に天体望遠鏡用ミラー１０（以下「ミラー１０」と記す）の概略構造を示す断面図を、図３にミラー１０の概略構造を示す斜視断面図を、それぞれ示す。この図３では、円盤状のミラー１０の内部構造を明確にするために、その半分のみを示しており、また、図２に示す符号１５の反射膜および符号１３ａ・１３ｂの接合部の図示を省略している。 Next, another mirror for an astronomical telescope according to the present invention in which the mirror 1 is reduced in weight while maintaining its high rigidity will be described.
FIG. 2 is a sectional view showing a schematic structure of the astronomical telescope mirror 10 (hereinafter referred to as “mirror 10”), and FIG. 3 is a perspective sectional view showing the schematic structure of the mirror 10. In FIG. 3, only half of the disk-like mirror 10 is shown in order to clarify the internal structure of the disk-like mirror 10, and the reflection film 15 and the joints 13 a and 13 b shown in FIG. 2 are shown. Omitted.

ミラー１０は、板部材１１ａ・１１ｂと、板部材１１ａの表面に設けられた反射膜１５と、板部材１１ａ・１１ｂに挟持されたコア部材１２と、板部材１１ａ・１１ｂとコア部材１２とをそれぞれ接合する接合部１３ａ・１３ｂと、を有している。つまり、板部材１１ａ・１１ｂとコア部材１２と接合部１３ａ・１３ｂが、ミラー部材を構成している。 The mirror 10 includes plate members 11a and 11b, a reflective film 15 provided on the surface of the plate member 11a, a core member 12 sandwiched between the plate members 11a and 11b, and the plate members 11a and 11b and the core member 12. It has joint part 13a * 13b to join, respectively. That is, the plate members 11a and 11b, the core member 12, and the joint portions 13a and 13b constitute a mirror member.

板部材１１ａ・１１ｂは低熱膨張セラミックスからなり、板部材１１ａの表面（接合部１３ａがある面とは反対側の面）が反射膜１５が設けられる反射面となっている。また、コア部材１２も低熱膨張セラミックスからなる。このコア部材１２は、隔壁１８により仕切られた多数の柱状の空隙部１７を有するハニカム構造体である。コア部材１２の開口面、つまり空隙部１７の長手方向に垂直な面にはそれぞれ、接続部１３ａ・１３ｂを介して板部材１１ａ・１１ｂが取り付けられている。ミラー１０は、このような中空構造を有するハニカム構造体を用いてミラー部材を構成しているために、先に説明したミラー１と比較して軽量である。しかも、材料選択を適切に行うことにより、所望の剛性を確保することができる。 The plate members 11a and 11b are made of low thermal expansion ceramics, and the surface of the plate member 11a (the surface opposite to the surface on which the joint portion 13a is provided) is a reflective surface on which the reflective film 15 is provided. The core member 12 is also made of a low thermal expansion ceramic. The core member 12 is a honeycomb structure having a large number of columnar voids 17 partitioned by partition walls 18. Plate members 11 a and 11 b are attached to the opening surface of the core member 12, that is, the surface perpendicular to the longitudinal direction of the gap portion 17 via connection portions 13 a and 13 b, respectively. The mirror 10 is lighter than the mirror 1 described above because the mirror member is configured using the honeycomb structure having such a hollow structure. Moreover, the desired rigidity can be ensured by appropriately selecting the material.

ミラー１を構成するミラー部材２と同様に、ミラー１０でも、板部材１１ａ・１１ｂとコア部材１２の−１０℃〜１０℃における平均の熱膨張係数は、−１×１０^−６〜１×１０^−６／℃の範囲にあることが好ましい。また、板部材１１ａ・１１ｂとコア部材１２をそれぞれ構成する、前記熱膨張係数を有する低熱膨張セラミックスとしては、先に説明したミラー１のミラー部材２に用いられるセラミックス材料と同じ複合材料が挙げられる。板部材１１ａ・１１ｂとコア部材１２を構成する低熱膨張性セラミックスの熱膨張係数の調整は、先に説明したミラー１を構成するミラー部材２用の低熱膨張性セラミックスの調整方法と同様の方法によって行うことができる。なお、板部材１１ａ・１１ｂとコア部材１２には同じ材料を用いることが好ましいが、熱膨張係数が前記範囲にあれば、異なる材料を用いることもできる。 Similarly to the mirror member 2 constituting the mirror 1, the average thermal expansion coefficient of the plate members 11 a and 11 b and the core member 12 at −10 ° C. to 10 ° C. is −1 × 10 ⁻⁶ to 1 × 10 10. It is preferably in the range of ⁻⁶ / ° C. Moreover, as the low thermal expansion ceramics having the thermal expansion coefficient, which constitute the plate members 11a and 11b and the core member 12, respectively, the same composite material as the ceramic material used for the mirror member 2 of the mirror 1 described above can be cited. . The adjustment of the thermal expansion coefficient of the low thermal expansion ceramics constituting the plate members 11a and 11b and the core member 12 is performed by the same method as the adjustment method of the low thermal expansion ceramics for the mirror member 2 constituting the mirror 1 described above. It can be carried out. The same material is preferably used for the plate members 11a and 11b and the core member 12, but different materials can be used as long as the thermal expansion coefficient is within the above range.

接合部１３ａ・１３ｂは、後述するミラー１０の製造プロセスを容易とし、またミラー１０の熱膨張破壊を防止する等の観点から、板部材１１ａ・１１ｂおよびコア部材１２を構成する低熱膨張セラミックスよりも溶融温度の低い低熱膨張セラミックスで構成される。なお、図２では説明のために接合部１３ａを明確に示しているが、実際のミラー１０における接合部１３ａ・１３ｂの厚みは数μｍ〜数十μｍ程度であり、コア部材１２の厚さ（開口面間の距離）よりも極めて薄いものである。 The joint portions 13a and 13b are easier than a low thermal expansion ceramic constituting the plate members 11a and 11b and the core member 12 from the viewpoint of facilitating the manufacturing process of the mirror 10 described later and preventing thermal expansion destruction of the mirror 10. Consists of low thermal expansion ceramics with low melting temperature. In FIG. 2, the joint portion 13 a is clearly shown for explanation, but the thickness of the joint portions 13 a and 13 b in the actual mirror 10 is about several μm to several tens μm, and the thickness of the core member 12 ( It is extremely thinner than the distance between the opening surfaces.

また、板部材１１ａ・１１ｂおよびコア部材１２の−１０℃〜１０℃における平均の熱膨張係数と、接合部１３ａ・１３ｂの−１０℃〜１０℃における平均の熱膨張係数との差は、±０．１×１０^−６／℃の範囲内であることが好ましい。これにより、板部材１１ａ・１１ｂとコア部材１２との接合処理時（ミラー１０の製造方法については後述する）における熱応力の発生を抑制し、高い強度でこれらを接合することができる。また、ミラー１０の使用環境下における形状精度が維持され、かつ、ミラー１０の使用温度が変化した場合の熱膨張歪みおよび熱収縮歪みの発生を抑制することができる。 Further, the difference between the average thermal expansion coefficient at −10 ° C. to 10 ° C. of the plate members 11a and 11b and the core member 12 and the average thermal expansion coefficient at −10 ° C. to 10 ° C. of the joint portions 13a and 13b is ± It is preferable to be within the range of 0.1 × 10 ⁻⁶ / ° C. Thereby, generation | occurrence | production of the thermal stress at the time of the joining process (The manufacturing method of the mirror 10 is mentioned later) at the time of joining of plate member 11a * 11b and the core member 12 can be suppressed, and these can be joined by high intensity | strength. In addition, the shape accuracy of the mirror 10 in the usage environment can be maintained, and the occurrence of thermal expansion distortion and thermal contraction distortion when the usage temperature of the mirror 10 changes can be suppressed.

接合部１３ａ・１３ｂを構成する低熱膨張セラミックスとしては、板部材１１ａ・１１ｂおよびコア部材１２に用いられるセラミックス材料と同じ複合材料が好適に用いられる。例えば、接合部１３ａ・１３ｂを構成する低熱膨張セラミックスの調製は、板部材１１ａ・１１ｂおよびコア部材１２の溶融温度および熱膨張係数を考慮して、第１の材料と第２の材料の配合比を決める方法、具体的には、板部材１１ａ・１１ｂを構成する第１の材料と第２の材料のうちの溶融温度が低い方の配合割合を高くすること等により、行うことができる。 As the low thermal expansion ceramics constituting the joint portions 13a and 13b, the same composite material as the ceramic material used for the plate members 11a and 11b and the core member 12 is preferably used. For example, the preparation of the low thermal expansion ceramics constituting the joint portions 13a and 13b is performed by taking into consideration the melting temperature and the thermal expansion coefficient of the plate members 11a and 11b and the core member 12, and the mixing ratio of the first material and the second material. For example, by increasing the blending ratio of the first material and the second material constituting the plate members 11a and 11b having the lower melting temperature.

ミラー１０の製造方法としては、板部材１１ａ・１１ｂとコア部材１２をそれぞれ別に製造し、これらを接合部１３ａ・１３ｂを構成するためのセラミックスペーストを用いて接合する方法が好適に用いられる。例えば、板部材１１ａ・１１ｂは、前記ミラー部材２と同様に製造することができる。また、コア部材１２は、粉体混練、押出成形、焼成という工程を経ることによって得ることができる。必要に応じて得られたハニカム構造体に、切削、研削加工を施す。 As a manufacturing method of the mirror 10, a method of manufacturing the plate members 11a and 11b and the core member 12 separately and bonding them using a ceramic paste for forming the bonding portions 13a and 13b is preferably used. For example, the plate members 11 a and 11 b can be manufactured in the same manner as the mirror member 2. Moreover, the core member 12 can be obtained through steps of powder kneading, extrusion molding, and firing. If necessary, the honeycomb structure obtained is subjected to cutting and grinding.

板部材１１ａ・１１ｂとコア部材１２の接合は、板部材１１ａ・１１ｂのそれぞれの表面およびコア部材１２の開口面にそれぞれ接合材たるセラミックスペーストを塗布し、これらの塗布面を合わせて荷重を掛けた状態で昇温し、セラミックスペーストを溶融させることによって行うことができる。板部材１１ａ・１１ｂとコア部材１２とを接合した後に、板部材１１ａの表面の鏡面研磨および反射膜形成を行う。 The plate members 11a and 11b and the core member 12 are bonded by applying a ceramic paste as a bonding material to the respective surfaces of the plate members 11a and 11b and the opening surface of the core member 12, and applying a load by applying these applied surfaces together. The temperature can be raised in a heated state to melt the ceramic paste. After joining the plate members 11a and 11b and the core member 12, the surface of the plate member 11a is mirror-polished and a reflective film is formed.

次に本発明の天体望遠鏡用ミラーのさらに別の実施形態について説明する。図４はミラー２０の概略断面図であり、図５はミラー２０の概略斜視断面図である。図５では、円盤状のミラー２０の内部構造を明確にするために、その半分のみを示しており、また、図４に示す符号２３の接合部と符号２５の反射膜の図示を省略している。 Next, still another embodiment of the astronomical telescope mirror of the present invention will be described. FIG. 4 is a schematic cross-sectional view of the mirror 20, and FIG. 5 is a schematic perspective cross-sectional view of the mirror 20. In FIG. 5, only half of the disk-shaped mirror 20 is shown in order to clarify the internal structure of the disk-like mirror 20, and the illustration of the junction part 23 and the reflection film 25 shown in FIG. 4 is omitted. Yes.

このミラー２０は、板部材２１と、板部材２１の表面に設けられた反射膜２５と、リブ構造を有する有底筒状のコア部材２２と、板部材２１とコア部材２２とを接合する接合部２３と、を有している。 The mirror 20 includes a plate member 21, a reflective film 25 provided on the surface of the plate member 21, a bottomed cylindrical core member 22 having a rib structure, and a joint that joins the plate member 21 and the core member 22. Part 23.

板部材２１は、先に説明したミラー１０の板部材１１と同じである。また、コア部材２２は、底壁に垂直に所定のパターンで設けられた隔壁２８によって空隙部２７が形成された構造を有する。ミラー２０は、このような中空構造を有するリブ構造体を用いてミラー部材を構成しているために、先に説明したミラー１と比較して軽量である。リブ構造を有するコア部材２２は、粉末調製、プレス成形、プレス成形体またはその仮焼体の加工、焼成、切削・研削という工程で作製す
ることができる。 The plate member 21 is the same as the plate member 11 of the mirror 10 described above. The core member 22 has a structure in which a gap portion 27 is formed by partition walls 28 provided in a predetermined pattern perpendicular to the bottom wall. The mirror 20 is lighter than the mirror 1 described above because the mirror member is configured by using the rib structure having such a hollow structure. The core member 22 having a rib structure can be produced by steps of powder preparation, press molding, press-molded body or processing of the calcined body, firing, cutting and grinding.

板部材２１とコア部材２２に求められる熱膨張係数等の特性や板部材２１とコア部材２２の接合方法等はミラー１０の場合に準じ、接合部２３もミラー１０における接合部１３ａに準ずるので、ここでの説明は割愛する。 The characteristics such as the thermal expansion coefficient required for the plate member 21 and the core member 22 and the joining method of the plate member 21 and the core member 22 are the same as in the case of the mirror 10, and the joining portion 23 is also in accordance with the joining portion 13a in the mirror 10. I'll omit the explanation here.

なお、ミラー１０を構成するハニカム構造体とミラー２０を構成するリブ構造体とは、隔壁によって空隙部が形成された中空構造を有する点で共通するために、これらの境界が問題となるが、これらに厳密な区別があるわけではない。ここでは、隔壁厚が厚く、セル幅も広いため、無垢構造体（またはその成形体）を機械加工して空隙部を形成することができるもの、または、無垢構造体に対する重量割合が５０％超の中空構造物をリブ構造体と呼ぶこととする。逆に、隔壁厚が薄く、セル幅（隔壁間距離）が狭いために、無垢構造体を機械加工することにより得ることが困難であり、その成形に押出成形法が好適に用いられるもの、または無垢構造体に対する重量割合が５０％超の中空構造物をハニカム構造体と呼ぶこととする。ミラーの構成部材としてハニカム構造体とリブ構造体のいずれを選択するかは、例えば、無垢構造体に対する軽量化割合や生産コスト等を考慮して定めることができる。 The honeycomb structure constituting the mirror 10 and the rib structure constituting the mirror 20 are common in that they have a hollow structure in which gaps are formed by the partition walls, and therefore these boundaries are problematic. There is no strict distinction between them. Here, since the partition wall is thick and the cell width is wide, the solid structure (or its molded body) can be machined to form a void, or the weight ratio to the solid structure exceeds 50%. This hollow structure is called a rib structure. Conversely, since the partition wall thickness is thin and the cell width (distance between the partition walls) is narrow, it is difficult to obtain a solid structure by machining, and an extrusion method is suitably used for the molding, or A hollow structure having a weight ratio exceeding 50% with respect to the solid structure will be referred to as a honeycomb structure. Which of the honeycomb structure and the rib structure is selected as the constituent member of the mirror can be determined in consideration of, for example, the weight reduction ratio and the production cost with respect to the solid structure.

以上、本発明の実施の形態について説明したが、本発明はこのような形態に限定されるものではない。例えば、図６の断面図に示すミラー３０は、図４および図５に示したミラー２０のコア部材２２を無垢構造を有するコア部材２２ａとした例である。このような構造は、板部材２１とコア部材２２ａとの材料（成分や組成）が異なる場合であって、その重量が天体望遠鏡の支持体への装着が許容される範囲の場合に採用することができる。 As mentioned above, although embodiment of this invention was described, this invention is not limited to such a form. For example, the mirror 30 shown in the sectional view of FIG. 6 is an example in which the core member 22 of the mirror 20 shown in FIGS. 4 and 5 is a core member 22a having a solid structure. Such a structure is adopted when the material (component or composition) of the plate member 21 and the core member 22a is different and the weight is within a range that allows the astronomical telescope to be mounted on the support. Can do.

また、ミラー１０においては、ハニカム構造を有するコア部材１２として、セル形状（空隙部１７の長手方向に垂直な面の形状）が略正方形のものを示したが、セル形状は正六角形等の多角形であってもよい。さらに、ミラー１０では、コア部材として１個のハニカム構造体を用いた形態を示しているが、複数のハニカム構造体を並べて配置してもよいし、ミラー部材が大型化するにしたがって、複数のハニカム構造体を用いる方がむしろ、ハニカム構造体の生産効率を高める観点から好ましい。 In the mirror 10, the core member 12 having a honeycomb structure has a cell shape (a shape perpendicular to the longitudinal direction of the gap portion 17) having a substantially square shape, but the cell shape may be a regular hexagon or the like. It may be square. Furthermore, although the mirror 10 shows a form in which one honeycomb structure is used as the core member, a plurality of honeycomb structures may be arranged side by side, and as the mirror member increases in size, a plurality of honeycomb structures may be arranged. Rather, it is preferable to use a honeycomb structure from the viewpoint of increasing the production efficiency of the honeycomb structure.

さらにまた、ミラー２０においては、リブ構造を有するコア部材２２として空隙部２７の開口面形状が略三角形のものを示したが、この空隙部の開口面形状は多角形や円形であってもよい。また、ミラー２０においては、板部材２１を反射面とすることなく、コア部材２２の表面（底壁の外側表面）を反射面としてもよい。 Further, in the mirror 20, the core member 22 having a rib structure has a substantially triangular opening surface shape of the gap portion 27. However, the opening surface shape of the gap portion may be a polygon or a circle. . Moreover, in the mirror 20, it is good also considering the surface (outer surface of a bottom wall) of the core member 22 as a reflective surface, without making the plate member 21 into a reflective surface.

（実施例１）
β−ユークリプタイト粉末と炭化珪素粉末とを、８０：２０の重量割合でポットミル混合して乾燥させ、原料混合粉末を作製した。この混合粉末を１２０ＭＰａの圧力でＣＩＰ成形してφ３８０ｍｍ×７０ｍｍの成形体を作製した。この成形体を５００℃で脱脂した後、窒素雰囲気において１３４０℃で焼成し、β−ユークリプタイトと炭化珪素とが複合されたセラミックス焼結体を得た。得られた焼結体に機械仕上げ加工を施し、φ３００ｍｍ×６０ｍｍの円盤状部材を得た。次いで、この円盤状部材の一方の主面を、表面粗さＲａが１０ｎｍ以下となるように、鏡面研磨加工した。この鏡面研磨面に反射膜たるＡｌ−ＳｉＯ_２積層膜を蒸着法により形成し、実施例１に係るミラーを得た。 (Example 1)
β-eucryptite powder and silicon carbide powder were mixed in a pot mill at a weight ratio of 80:20 and dried to prepare a raw material mixed powder. This mixed powder was subjected to CIP molding at a pressure of 120 MPa to produce a molded body of φ380 mm × 70 mm. This molded body was degreased at 500 ° C. and then fired at 1340 ° C. in a nitrogen atmosphere to obtain a ceramic sintered body in which β-eucryptite and silicon carbide were combined. The obtained sintered body was subjected to mechanical finishing to obtain a disk-shaped member having a diameter of 300 mm × 60 mm. Subsequently, one main surface of this disk-shaped member was mirror-polished so that surface roughness Ra might be 10 nm or less. An Al—SiO ₂ laminated film as a reflective film was formed on this mirror polished surface by a vapor deposition method to obtain a mirror according to Example 1.

これとは別に、上記円盤状部材と同じ材料からなる焼結体を、上記円盤状部材の製造方法に準じて作製し、その焼結体から４ｍｍ×４ｍｍ×１２ｍｍの試験片を切り出した。レーザー干渉式熱膨張測定装置（アルバック理工社製ＬＩＸ−１）を用いて、得られた試験片の−１０〜１０℃における試験片の変位量を測定し、その熱膨張係数を求めた。また、この試験片のヤング率を測定した。これらの結果を表１に示す。 Separately, a sintered body made of the same material as the disk-shaped member was produced according to the method for manufacturing the disk-shaped member, and a test piece of 4 mm × 4 mm × 12 mm was cut out from the sintered body. Using a laser interference thermal expansion measuring device (LIX-1 manufactured by ULVAC-RIKO), the displacement of the obtained test piece at −10 to 10 ° C. was measured, and the thermal expansion coefficient was obtained. Moreover, the Young's modulus of this test piece was measured. These results are shown in Table 1.

また、鏡面研磨加工後の鏡面研磨面の表面粗さを触針式表面粗さ測定機ＴＡＬＹＳＵＲＦ（Ｔａｙｌｏｒ−Ｈｏｂｓｏｎ社製）により測定した。なお、実際には、この測定機により鏡面研磨面の表面粗さを確認しながら、表面粗さＲａが１０ｎｍ以下となるまで、鏡面研磨加工を行った。さらに、反射膜を形成後の反射率を、波長６３３ｎｍのＨｅ−Ｎｅレーザー光をこのミラー面に対して垂直に照射し、反射光強度を測定した。さらに、ミラーの重量を測定した。これらの結果を表２に示す。 Further, the surface roughness of the mirror-polished surface after the mirror-polishing was measured with a stylus type surface roughness measuring device TALYSURF (manufactured by Taylor-Hobson). In practice, mirror polishing was performed until the surface roughness Ra was 10 nm or less while confirming the surface roughness of the mirror polished surface with this measuring machine. Further, the reflectance after forming the reflective film was irradiated with He—Ne laser light having a wavelength of 633 nm perpendicular to the mirror surface, and the reflected light intensity was measured. Furthermore, the weight of the mirror was measured. These results are shown in Table 2.

（実施例２）
β−ユークリプタイト粉末と炭化珪素粉末とを、７０：３０の重量割合でポットミル混合して乾燥させ、原料混合粉末を作製した。この混合粉末を１２０ＭＰａの圧力でＣＩＰ成形し、（Ａ）φ３８０ｍｍ×２０ｍｍ、（Ｂ）φ３８０ｍｍ×６０ｍｍの２種類の成形体を作製し、（Ｂ）の成形体には、略三角柱状で深さ５０ｍｍの空隙部が、幅が１３ｍｍの隔壁によって形成されるように、機械加工を施した。こうして得られた各成形体を５００℃で脱脂した後、窒素雰囲気において１３６０℃で焼成し、β−ユークリプタイトと炭化珪素とが複合されたセラミックス焼結体を得た。得られた（Ａ）の焼結体をφ３００ｍｍ×１０ｍｍ、（Ｂ）の焼結体をφ３００ｍｍ×５０ｍｍに、それぞれ機械仕上げ加工した。 (Example 2)
β-eucryptite powder and silicon carbide powder were mixed in a pot mill at a weight ratio of 70:30 and dried to prepare a raw material mixed powder. This mixed powder was subjected to CIP molding at a pressure of 120 MPa to produce two types of molded bodies (A) φ380 mm × 20 mm and (B) φ380 mm × 60 mm. The molded body of (B) has a substantially triangular prism shape and a depth. Machining was performed so that a 50 mm gap was formed by a partition wall having a width of 13 mm. Each molded body thus obtained was degreased at 500 ° C. and then fired at 1360 ° C. in a nitrogen atmosphere to obtain a ceramic sintered body in which β-eucryptite and silicon carbide were combined. The obtained sintered body (A) was machine finished to φ300 mm × 10 mm, and the sintered body (B) was machine finished to φ300 mm × 50 mm.

一方、β−ユークリプタイトと炭化珪素とを、６０：４０の重量割合でポットミル混合して乾燥させ、接合材用の混合粉末を作製した。この混合粉末を無機分が３０ｖｏｌ％となるようにエチルセルロースの１５％α−テルピネオール溶液と混合し、三本ロールを用いてペースト状にし、接合材ペーストを作製した。 On the other hand, β-eucryptite and silicon carbide were mixed in a pot mill at a weight ratio of 60:40 and dried to prepare a mixed powder for a bonding material. This mixed powder was mixed with a 15% α-terpineol solution of ethyl cellulose so that the inorganic content was 30 vol%, and made into a paste using a three roll to prepare a bonding material paste.

前記（Ａ）の焼結体の片面および（Ｂ）の焼結体の片面（開口面）の対応する部分に、上記接合材ペーストをスクリーンマスクを用いて厚さ３０μｍに印刷、乾燥させた後、これらを５００℃に昇温して、塗布された接合材ペーストを脱脂した。その後、印刷面同士を接着して１．５ｇ／ｍｍ^２の荷重をかけた。引き続き、この接着体を窒素雰囲気で１３５０℃の温度で熱処理し、接合材を溶融させて焼結体（Ａ）・（Ｂ）を接合した。 After printing and drying the bonding material paste to a thickness of 30 μm on one side of the sintered body of (A) and the corresponding part of one side (opening surface) of the sintered body of (B) using a screen mask. These were heated to 500 ° C. to degrease the applied bonding material paste. Thereafter, the printed surfaces were bonded to each other and a load of 1.5 g / mm ² was applied. Subsequently, this bonded body was heat-treated at a temperature of 1350 ° C. in a nitrogen atmosphere, and the bonding material was melted to bond the sintered bodies (A) and (B).

次いで、得られた接合体の一方の主面（例えば、（Ａ）の焼結体の表面）を鏡面研磨加工して、その表面粗さＲａを１０ｎｍ以下とし、この鏡面研磨面に反射膜たるＡｌ−ＳｉＯ_２積層膜を蒸着法により形成し、実施例２に係るミラーを得た。 Next, one main surface (for example, the surface of the sintered body of (A)) of the obtained bonded body is mirror-polished to have a surface roughness Ra of 10 nm or less, and this mirror-polished surface is a reflective film. An Al—SiO ₂ laminated film was formed by a vapor deposition method to obtain a mirror according to Example 2.

これとは別に、上記（Ａ）・（Ｂ）の焼結体と同じ材料からなる焼結体を、上記（Ａ）・（Ｂ）の焼結体の製造方法に準じて作製し、その焼結体から４ｍｍ×４ｍｍ×１２ｍｍの試験片を切り出した。この試験片について、実施例１の場合と同様にして、熱膨張係数、ヤング率を測定した。これらの結果を表１に示す。また、作製した実施例２に係るミラーの反射率、重量を、実施例１の場合と同様にして、測定した。また、実施例２に係るミラーのヤング率を測定した。その結果を表２に示す。 Separately, a sintered body made of the same material as the sintered bodies of the above (A) and (B) is produced according to the manufacturing method of the sintered body of the above (A) and (B), and the sintered body is sintered. A test piece of 4 mm × 4 mm × 12 mm was cut out from the ligature. About this test piece, it carried out similarly to the case of Example 1, and measured the thermal expansion coefficient and the Young's modulus. These results are shown in Table 1. Further, the reflectance and weight of the produced mirror according to Example 2 were measured in the same manner as in Example 1. Further, the Young's modulus of the mirror according to Example 2 was measured. The results are shown in Table 2.

さらにこれとは別に、上記接合材ペーストと同じ材料からなる焼結体を、上記接合処理温度で焼成することによって作製し、その焼結体から４ｍｍ×４ｍｍ×１２ｍｍの試験片を切り出した。この試験片について、実施例１の場合と同様にして、熱膨張係数、ヤング率を測定した。これらの結果を表１に示す。 Further, separately from this, a sintered body made of the same material as the bonding material paste was fired at the bonding processing temperature, and a test piece of 4 mm × 4 mm × 12 mm was cut out from the sintered body. About this test piece, it carried out similarly to the case of Example 1, and measured the thermal expansion coefficient and the Young's modulus. These results are shown in Table 1.

（実施例３）
β−ユークリプタイト粉末と炭化珪素粉末とを、６０：４０の重量割合でポットミル混合して乾燥させ、原料混合粉末を作製した。この混合粉末を１２０ＭＰａの圧力でＣＩＰ成形してφ３８０ｍｍ×２０ｍｍの成形体を２枚作製した。これらの成形体を５００℃で脱脂した後、窒素雰囲気において１３８０℃で焼成し、β−ユークリプタイトと炭化珪素とが複合されたセラミックス焼結体を得た。これらのセラミックス焼結体を機会仕上げ加工して、φ３００ｍｍ×１０ｍｍの板部材とした。 (Example 3)
β-eucryptite powder and silicon carbide powder were mixed in a pot mill at a weight ratio of 60:40 and dried to prepare a raw material mixed powder. This mixed powder was subjected to CIP molding at a pressure of 120 MPa to produce two compacts having a diameter of 380 mm × 20 mm. These compacts were degreased at 500 ° C. and then fired at 1380 ° C. in a nitrogen atmosphere to obtain a ceramic sintered body in which β-eucryptite and silicon carbide were combined. These ceramic sintered bodies were opportunity finished and processed into plate members having a diameter of 300 mm × 10 mm.

また、上記原料粉末にメチルセルロース系バインダを１０重量部混合し、ニーダによって混練した後、押出成形機を用いて、隔壁厚が２ｍｍ、空隙部の開口径が１０ｍｍ（空隙部の開口断面の形状が正方形で、この正方形の一辺の長さが１０ｍｍ）、外寸が１１０ｍｍ×１１０ｍｍ、厚み（押出方向の長さ）が５５ｍｍのハニカム構造を有する押出成形体を作製した。この成形体を５００℃で脱脂した後、窒素雰囲気下、１３８０℃で焼成し、β−ユークリプタイトと炭化珪素とが複合されたセラミックスハニカム焼結体を得た。得られたハニカム焼結体を、その厚みが４０ｍｍとなるように研削加工し、さらに外寸の一辺が７５ｍｍとなるように切断して、１個のセラミックスハニカム焼結体から複数のハニカム構造体を得た。一方、β−ユークリプタイトと炭化珪素とが５０：５０の重量割合で混合された接合材ペーストを、前記実施例２と同様の方法により作製した。 Also, after mixing 10 parts by weight of methylcellulose binder with the above raw material powder and kneading with a kneader, using an extrusion molding machine, the partition wall thickness was 2 mm and the opening diameter of the cavity was 10 mm (the shape of the opening cross section of the cavity was An extrusion-molded body having a honeycomb structure having a square shape with a side length of 10 mm), an outer dimension of 110 mm × 110 mm, and a thickness (length in the extrusion direction) of 55 mm was produced. This molded body was degreased at 500 ° C. and then fired at 1380 ° C. in a nitrogen atmosphere to obtain a ceramic honeycomb sintered body in which β-eucryptite and silicon carbide were combined. The obtained honeycomb sintered body is ground so as to have a thickness of 40 mm, and further cut so that one side of the outer dimension is 75 mm, from one ceramic honeycomb sintered body to a plurality of honeycomb structures. Got. On the other hand, a bonding material paste in which β-eucryptite and silicon carbide were mixed at a weight ratio of 50:50 was produced by the same method as in Example 2.

作製した２枚の板部材のそれぞれの片面とハニカム構造体の両方の開口面の所定位置に、作製した接合材ペーストをスクリーンマスクを用いて厚さ３０μｍで印刷し、乾燥させた後、これらを５００℃に昇温して、塗布された接合材ペーストを脱脂した。その後、板部材の全面にハニカム構造体が配設されるように、複数のハニカム構造体を１枚の板部材上に複数個並べて接着し、さらにハニカム構造体の上に別の１枚の板部材を載置して接着し、１．５ｇ／ｍｍ^２の荷重をかけた。引き続き、この接着体を窒素雰囲気で１３６０℃の温度で熱処理して、セラミックスペーストを溶融させ、板部材によってハニカム構造体が挟持された接合体を得た。 The prepared bonding material paste is printed at a thickness of 30 μm using a screen mask at a predetermined position on each of one side of the two produced plate members and the opening surface of the honeycomb structure, and then dried. The temperature was raised to 500 ° C., and the applied bonding material paste was degreased. Thereafter, a plurality of honeycomb structures are arranged and bonded on one plate member so that the honeycomb structure is disposed on the entire surface of the plate member, and another plate is further formed on the honeycomb structure. The member was mounted and adhered, and a load of 1.5 g / mm ² was applied. Subsequently, this bonded body was heat-treated at a temperature of 1360 ° C. in a nitrogen atmosphere to melt the ceramic paste, thereby obtaining a bonded body in which the honeycomb structure was sandwiched by the plate members.

次いで、得られた接合体の一方の板部材の主面を、その表面粗さＲａが１０ｎｍ以下となるように鏡面研磨加工して、その表面粗さＲａを１０ｎｍ以下とし、この鏡面研磨面に反射膜たるＡｌ−ＳｉＯ_２積層膜を蒸着法により形成し、実施例３に係るミラーを得た。 Next, the main surface of one plate member of the obtained joined body is mirror-polished so that the surface roughness Ra is 10 nm or less, and the surface roughness Ra is 10 nm or less. An Al—SiO ₂ laminated film as a reflective film was formed by vapor deposition to obtain a mirror according to Example 3.

これとは別に、上記板部材およびハニカム構造体と同じ材料からなる焼結体を、上記板部材の焼結体の製造方法に準じて作製し、その焼結体から４ｍｍ×４ｍｍ×１２ｍｍの試験片を切り出した。この試験片について、実施例１の場合と同様にして、熱膨張係数、ヤング率を測定した。これらの結果を表１に示す。また、作製した実施例３に係るミラーの反射率、重量を、実施例１の場合と同様にして測定し、実施例３に係るミラーのヤング率を実施例２に係るミラーのヤング率測定と同様に行った。その結果を表２に示す。 Separately, a sintered body made of the same material as the plate member and the honeycomb structure is manufactured according to the method for manufacturing the sintered body of the plate member, and a test of 4 mm × 4 mm × 12 mm is performed from the sintered body. A piece was cut out. About this test piece, it carried out similarly to the case of Example 1, and measured the thermal expansion coefficient and the Young's modulus. These results are shown in Table 1. Further, the reflectance and weight of the manufactured mirror according to Example 3 were measured in the same manner as in Example 1, and the Young's modulus of the mirror according to Example 3 was measured as the Young's modulus of the mirror according to Example 2. The same was done. The results are shown in Table 2.

（結果）
実施例１〜３のミラーでは、従来のガラスを用いたヤング率が８０〜１００ＧＰａのミラーよりも高い剛性を示した。また、実施例２および実施例３に係るミラーは、実施例１よりも軽量でありながら、高いヤング率を有する高剛性なミラーであることが確認された。さらに、これら実施例に係るミラーでは、反射面の表面粗さがＲａで１０ｎｍ以下となっているために、高い反射率が得られた。 (result)
In the mirrors of Examples 1 to 3, the Young's modulus using conventional glass showed higher rigidity than the mirror of 80 to 100 GPa. In addition, it was confirmed that the mirrors according to Example 2 and Example 3 were highly rigid mirrors having a high Young's modulus while being lighter than Example 1. Further, in the mirrors according to these examples, since the surface roughness of the reflecting surface was 10 nm or less in Ra, a high reflectance was obtained.

本発明に係る天体望遠鏡用ミラーの第１の実施形態を示す概略断面図。1 is a schematic sectional view showing a first embodiment of an astronomical telescope mirror according to the present invention. 本発明に係る天体望遠鏡用ミラーの第２の実施形態を示す概略断面図。The schematic sectional drawing which shows 2nd Embodiment of the mirror for astronomical telescopes which concerns on this invention. 図２に示す天体望遠鏡用ミラーの概略構造を示す斜視断面図。FIG. 3 is a perspective sectional view showing a schematic structure of the astronomical telescope mirror shown in FIG. 2. 本発明に係る天体望遠鏡用ミラーの第３の実施形態を示す概略断面図。The schematic sectional drawing which shows 3rd Embodiment of the mirror for astronomical telescopes which concerns on this invention. 図４に示す天体望遠鏡用ミラーの概略構造を示す斜視断面図。FIG. 5 is a perspective sectional view showing a schematic structure of the astronomical telescope mirror shown in FIG. 4. 本発明に係る天体望遠鏡用ミラーの第４の実施形態を示す概略断面図。The schematic sectional drawing which shows 4th Embodiment of the mirror for astronomical telescopes which concerns on this invention.

符号の説明Explanation of symbols

１，１０，２０，３０；天体望遠鏡用ミラー
２；ミラー部材
３；反射膜
１１ａ，１１ｂ，２１；板部材
１２，２２；コア部材
１３ａ，１３ｂ，２３；接合部
１５，２５；反射膜
１７，２７；空隙部
１８，２８；隔壁 1, 10, 20, 30; Astronomical telescope mirror 2; Mirror member 3; Reflective film 11a, 11b, 21; Plate member 12, 22; Core member 13a, 13b, 23; 27; Cavity 18, 28; Bulkhead

Claims

天体望遠鏡に設けられ、天体から届き集光された光を反射させる天体望遠鏡用ミラーであって、
前記光を反射するための表面粗さがＲａで１０ｎｍ以下の反射面を備えた低熱膨張セラミックスからなるミラー部材と、
前記ミラー部材の反射面に設けられた所定の反射膜と、
を有することを特徴とする天体望遠鏡用ミラー。 An astronomical telescope mirror that is provided in the astronomical telescope and reflects light collected from the astronomical object,
A mirror member made of a low thermal expansion ceramic having a reflective surface with a surface roughness Ra of 10 nm or less for reflecting the light;
A predetermined reflective film provided on the reflective surface of the mirror member;
An astronomical telescope mirror characterized by comprising:

前記ミラー部材の−１０〜１０℃における平均の熱膨張係数が、−１×１０^−６〜１×１０^−６／℃の範囲にあることを特徴とする請求項１に記載の天体望遠鏡用ミラー。 2. The astronomical telescope mirror according to claim 1, wherein an average thermal expansion coefficient of the mirror member at −10 to 10 ° C. is in a range of −1 × 10 ⁻⁶ to 1 × 10 ⁻⁶ / ° C. 3. .

前記ミラー部材を構成する低熱膨張セラミックスは、リチウムアルミノシリケート、リン酸ジルコニウムカリウム、コーディエライトから選ばれる１種以上の第１の材料と、炭化珪素、窒化珪素、サイアロン、アルミナ、ジルコニア、ムライト、ジルコン、窒化アルミニウム、ケイ酸カルシウム、炭化ホウ素から選ばれる１種以上の第２の材料とを複合してなる複合材料であることを特徴とする請求項１または請求項２に記載の天体望遠鏡用ミラー。 The low thermal expansion ceramic constituting the mirror member includes at least one first material selected from lithium aluminosilicate, potassium zirconium phosphate, cordierite, silicon carbide, silicon nitride, sialon, alumina, zirconia, mullite, The astronomical telescope according to claim 1 or 2, wherein the astronomical telescope is a composite material formed by combining at least one second material selected from zircon, aluminum nitride, calcium silicate, and boron carbide. mirror.

天体望遠鏡に設けられ、天体から届き集光された光を反射させる天体望遠鏡用ミラーであって、
前記光を反射するための表面粗さがＲａで１０ｎｍ以下の反射面を備えた低熱膨張セラミックスからなる板部材と、
前記板部材の反射面に設けられた所定の反射膜と、
低熱膨張セラミックスからなり、前記板部材と接合されて前記板部材を保持するコア部材と、
前記板部材と前記コア部材とを接合する、前記板部材および前記コア部材を構成する低熱膨張セラミックスよりも溶融温度の低い低熱膨張セラミックスからなる接合部と、
を有することを特徴とする天体望遠鏡用ミラー。 An astronomical telescope mirror that is provided in the astronomical telescope and reflects light collected from the astronomical object,
A plate member made of low thermal expansion ceramics having a reflective surface with a surface roughness Ra of 10 nm or less for reflecting the light;
A predetermined reflective film provided on the reflective surface of the plate member;
A core member made of low thermal expansion ceramics and bonded to the plate member to hold the plate member;
Joining the plate member and the core member, a joint made of a low thermal expansion ceramic having a lower melting temperature than the low thermal expansion ceramic constituting the plate member and the core member;
An astronomical telescope mirror characterized by comprising:

前記板部材と前記コア部材の−１０〜１０℃における平均の熱膨張係数が、−１×１０^−６〜１×１０^−６／℃の範囲にあることを特徴とする請求項４に記載の天体望遠鏡用ミラー。 5. The average thermal expansion coefficient at −10 to 10 ° C. of the plate member and the core member is in the range of −1 × 10 ⁻⁶ to 1 × 10 ⁻⁶ / ° C. 5. Astronomical telescope mirror.

前記板部材および前記コア部材を構成する低熱膨張セラミックスと前記接合部を形成する低熱膨張セラミックスはそれぞれ、リチウムアルミノシリケート、リン酸ジルコニウムカリウム、コーディエライトから選ばれる１種以上の第１の材料と、炭化珪素、窒化珪素、サイアロン、アルミナ、ジルコニア、ムライト、ジルコン、窒化アルミニウム、ケイ酸カルシウム、炭化ホウ素から選ばれる１種以上の第２の材料とを複合してなる複合材料であることを特徴とする請求項４または請求項５に記載の天体望遠鏡用ミラー。 The low thermal expansion ceramics constituting the plate member and the core member and the low thermal expansion ceramics forming the joint are respectively one or more first materials selected from lithium aluminosilicate, potassium zirconium phosphate, and cordierite. And a composite material formed by combining at least one second material selected from silicon carbide, silicon nitride, sialon, alumina, zirconia, mullite, zircon, aluminum nitride, calcium silicate, and boron carbide. The astronomical telescope mirror according to claim 4 or 5.

前記板部材および前記コア部材の−１０〜１０℃における平均の熱膨張係数と、前記接合部の−１０〜１０℃における平均の熱膨張係数との差が±０．１×１０^−６／℃の範囲内であることを特徴とする請求項４から請求項６のいずれか１項に記載の天体望遠鏡用ミラー。 The difference between the average thermal expansion coefficient at −10 to 10 ° C. of the plate member and the core member and the average thermal expansion coefficient at −10 to 10 ° C. of the joint is ± 0.1 × 10 ⁻⁶ / ° C. The astronomical telescope mirror according to any one of claims 4 to 6, wherein the astronomical telescope mirror is within the range.

前記コア部材はハニカム構造体であって、
低熱膨張性セラミックスからなる別の板部材と、
前記別の板部材と前記ハニカム構造体とを接合する、前記別の板部材および前記ハニカム構造体を構成する低熱膨張セラミックスよりも溶融温度の低い別の低熱膨張性セラミックスからなる別の接合部と、
をさらに具備し、
前記ハニカム構造体の上下開口面にそれぞれ前記板部材および前記別の板部材が接合されていることを特徴とする請求項４から請求項７のいずれか１項に記載の天体望遠鏡用ミラー。 The core member is a honeycomb structure,
Another plate member made of low thermal expansion ceramics;
Another joint member made of another low thermal expansion ceramic having a melting temperature lower than that of the low thermal expansion ceramic constituting the another plate member and the honeycomb structure, which joins the another plate member and the honeycomb structure; ,
Further comprising
The astronomical telescope mirror according to any one of claims 4 to 7, wherein the plate member and the another plate member are respectively joined to the upper and lower opening surfaces of the honeycomb structure.

前記コア部材は、有底上面開口型のリブ構造体であって、
前記リブ構造体の開口面に前記板部材が接合されていることを特徴とする請求項４から請求項７のいずれか１項に記載の天体望遠鏡用ミラー。 The core member is a bottomed open top rib structure,
The astronomical telescope mirror according to any one of claims 4 to 7, wherein the plate member is joined to an opening surface of the rib structure.