JP2648056B2 - Electroacoustic conversion diaphragm and method of manufacturing the same - Google Patents
Electroacoustic conversion diaphragm and method of manufacturing the sameInfo
- Publication number
- JP2648056B2 JP2648056B2 JP3230078A JP23007891A JP2648056B2 JP 2648056 B2 JP2648056 B2 JP 2648056B2 JP 3230078 A JP3230078 A JP 3230078A JP 23007891 A JP23007891 A JP 23007891A JP 2648056 B2 JP2648056 B2 JP 2648056B2
- Authority
- JP
- Japan
- Prior art keywords
- diaphragm
- porous ceramic
- fiber
- pulp
- ceramic particles
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 12
- 238000006243 chemical reaction Methods 0.000 title claims description 9
- 239000000835 fiber Substances 0.000 claims description 24
- 239000000919 ceramic Substances 0.000 claims description 16
- 239000002245 particle Substances 0.000 claims description 16
- 239000000203 mixture Substances 0.000 claims description 9
- 239000011230 binding agent Substances 0.000 claims description 8
- 235000007164 Oryza sativa Nutrition 0.000 claims description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 6
- 239000011347 resin Substances 0.000 claims description 6
- 229920005989 resin Polymers 0.000 claims description 6
- 235000009566 rice Nutrition 0.000 claims description 6
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 4
- 229910052760 oxygen Inorganic materials 0.000 claims description 4
- 239000001301 oxygen Substances 0.000 claims description 4
- 239000012209 synthetic fiber Substances 0.000 claims description 4
- 229920002994 synthetic fiber Polymers 0.000 claims description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 3
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 238000000465 moulding Methods 0.000 claims description 3
- 229910052700 potassium Inorganic materials 0.000 claims description 3
- 239000011591 potassium Substances 0.000 claims description 3
- 239000010903 husk Substances 0.000 claims description 2
- 240000007594 Oryza sativa Species 0.000 claims 1
- 239000011800 void material Substances 0.000 claims 1
- 239000000463 material Substances 0.000 description 12
- 241000209094 Oryza Species 0.000 description 5
- 239000002657 fibrous material Substances 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000010445 mica Substances 0.000 description 3
- 229910052618 mica group Inorganic materials 0.000 description 3
- 229920000049 Carbon (fiber) Polymers 0.000 description 2
- 229920001131 Pulp (paper) Polymers 0.000 description 2
- 239000004917 carbon fiber Substances 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000003801 milling Methods 0.000 description 2
- 230000008520 organization Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000010009 beating Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000012784 inorganic fiber Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 238000004452 microanalysis Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 229910021426 porous silicon Inorganic materials 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Landscapes
- Diaphragms For Electromechanical Transducers (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、スピーカ等の電気音響
変換器に用いる振動板及びその製造方法に関するもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm used for an electroacoustic transducer such as a speaker and a method of manufacturing the same.
【０００２】[0002]
【従来の技術】近年のデジタルオーディオ技術の進歩に
伴って、その周辺装置に対しても高性能化の要求が高ま
っており、放音部となるスピーカに用いる振動板におい
ては、従来よりも振動板素材のヤング率を大きく、密度
を小さくすると共に、内部損失を大きくすることが改善
目標となっている。ヤング率Ｅを大きく且つ密度ρを小
さくすることによって音速(Ｅ／ρ)0.5が上昇し、この
音速が分割振動の始まる音域(周波数)に比例するため、
音速が高い程、スピーカの高域特性が良好となる。又、
内部損失が大きい程、スピーカの分割振動が始まる音域
での異常音が小さく、且つ歪成分が少なくなるのであ
る。2. Description of the Related Art With the recent advancement of digital audio technology, there has been an increasing demand for higher performance of peripheral devices. Improvement goals include increasing the Young's modulus and decreasing the density of the plate material and increasing the internal loss. By increasing the Young's modulus E and decreasing the density ρ, the sound speed (E / ρ) 0.5 increases, and this sound speed is proportional to the sound range (frequency) at which the divided vibration starts.
The higher the speed of sound, the better the high-frequency characteristics of the speaker. or,
The larger the internal loss, the smaller the abnormal sound in the sound range where the divided vibration of the speaker starts, and the smaller the distortion component.
【０００３】そこで、スピーカ振動板の素材として繊維
系資材を用いることにより、内部損失の増大が図られて
いる。斯種振動板は、主原料のパルプに適当な有機繊
維、無機繊維を混抄して製造され、具体的には、パルプ
の叩解、抄紙、プレス、仕上げの各工程を経て製造され
る。又、内部損失を更に増大させるため、パルプ剤に精
製粘度を吸着させたものを抄紙してなる振動板が提案さ
れている(特公昭53-29101号〔H04R7/02〕)。[0003] Therefore, internal loss is increased by using a fiber material as a material of the speaker diaphragm. Such a diaphragm is manufactured by mixing appropriate organic fibers and inorganic fibers with the pulp as a main raw material, and specifically, is manufactured through each process of beating, papermaking, pressing, and finishing the pulp. Further, in order to further increase the internal loss, a diaphragm made of paper made by adsorbing a purified viscosity to a pulp agent has been proposed (JP-B-53-29101 [H04R7 / 02]).
【０００４】ところで、繊維系素材からなる振動板にお
いては、その内部損失を大きく保ったまま、如何にヤン
グ率を上げ、然も密度を下げるかが課題となる。即ち、
繊維系資材からなる振動板は、図２に示す如くパルプ繊
維(２)が樹脂バインダー(３)にて連結された構造を有し
ており、パルプ繊維(２)間の空隙の存在及びパルプ繊維
(２)自体の材料特性によって、本質的にヤング率が低
く、金属系振動板の如き高ヤング率を得ることは出来な
い。In a diaphragm made of a fibrous material, how to increase the Young's modulus and lower the density while maintaining a large internal loss is a problem. That is,
The diaphragm made of a fibrous material has a structure in which pulp fibers (2) are connected by a resin binder (3) as shown in FIG. 2, and the presence of voids between the pulp fibers (2) and the pulp fibers
(2) The Young's modulus is essentially low due to the material properties of itself, and a high Young's modulus like a metal diaphragm cannot be obtained.
【０００５】そこで、パルプ繊材と他の材料とを混抄し
て振動板素材を製造することが考えられる。例えば、高
ヤング率を有するカーボン短繊維と高内部損失を有する
マイカ粒子(雲母)とを混抄して、高ヤング率と高内部損
失を兼ね具えた振動板を製造することが可能である。Therefore, it is conceivable to manufacture a diaphragm material by mixing pulp fiber and other materials. For example, a diaphragm having both a high Young's modulus and a high internal loss can be manufactured by mixing a short carbon fiber having a high Young's modulus and mica particles (mica) having a high internal loss.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、カーボ
ン短繊維とマイカ粒子を混抄してなる振動板素材におい
ては、これらの材料が高価であるばかりでなく、従来の
繊維系資材に比べて密度が大きくなるため、音速が然程
上昇しない問題があった。本発明の目的は、安価で、従
来よりも音速が高く、然も内部損失が大きい素材からな
る振動板、及びその製造方法を提供することである。However, in a diaphragm material made of a mixture of short carbon fibers and mica particles, these materials are not only expensive but also have a higher density than conventional fiber materials. Therefore, there is a problem that the sound speed does not rise so much. An object of the present invention is to provide a diaphragm made of a material that is inexpensive, has a higher sound velocity than conventional ones, and has a large internal loss, and a method of manufacturing the same.
【０００７】[0007]
【課題を解決する為の手段】本発明に係る電気音響変換
用振動板は、天然繊維、合成繊維若しくはこれらの混合
物からなるパルプ繊維(２)間の空隙部に、酸化珪素を主
成分とする多孔質セラミクス粒(４)を包埋せしめて形成
される。The diaphragm for electroacoustic conversion according to the present invention comprises silicon oxide as a main component in the gap between pulp fibers (2) made of natural fibers, synthetic fibers or a mixture thereof. It is formed by embedding the porous ceramic particles (4).
【０００８】又、本発明に係る電気音響変換用振動板の
製造方法は、籾殻を略１０００乃至１５００℃の酸素中
にて燃焼させて得られるセラミクス系残留物を、天然繊
維、合成繊維若しくはこれらの混合物からなるパルプ繊
維(２)と、樹脂バインダー(３)を介して混抄させ、これ
を抄造し、成型することを特徴とする。The method for producing a diaphragm for electroacoustic conversion according to the present invention is characterized in that a ceramic residue obtained by burning rice husk in oxygen at about 1000 to 1500 ° C. is converted into natural fiber, synthetic fiber or Pulp fiber (2) comprising a mixture of the above and a resin binder (3), and the mixture is paper-formed and molded.
【０００９】[0009]
【作用及び効果】本発明に係る電気音響変換用振動板に
おいて、多孔質セラミクス粒(４)は、ガラス質の特徴、
即ち高剛性を有すると共に、その微細な多孔質構造によ
って、軽量性と吸音効果を具えている。従って、多孔質
セラミクス粒(４)がパルプ繊維(２)間の空隙部に緻密に
散在することによって、架橋効果を発揮して、振動板素
材のヤング率を上げると共に、パルプ繊維(２)が有する
高内部損失を損うことなく、高音速を実現出来る。In the diaphragm for electroacoustic conversion according to the present invention, the porous ceramic particles (4) are characterized by vitreous characteristics,
In other words, it has high rigidity and its lightweight structure and sound absorbing effect due to its fine porous structure. Therefore, the porous ceramic particles (4) are densely scattered in the gaps between the pulp fibers (2), thereby exhibiting a crosslinking effect, increasing the Young's modulus of the diaphragm material, and increasing the pulp fibers (2). High sound velocity can be realized without impairing the high internal loss.
【００１０】又これと同時に、パルプ繊維(２)と多孔質
セラミクス粒(４)の異種物質どうしの接触により、振動
板の振動時に発生する摩擦が熱となって振動板内部に蓄
積し、これによって更に内部損失が増大することにな
る。At the same time, due to the contact between the different substances of the pulp fiber (2) and the porous ceramic particles (4), the friction generated when the diaphragm vibrates becomes heat and accumulates inside the diaphragm. As a result, the internal loss further increases.
【００１１】本発明に係る電気音響変換用振動板の製造
方法においては、精米後に残る籾殻を略１０００乃至１
５００℃の酸素中にて燃焼させることによって、酸化珪
素を主成分とする多孔質セラミクス粒(４)が得られる。
従って、該多孔質セラミクス粒(４)を、樹脂バインダー
(３)を介してパルプ繊維(２)と混抄させ、これを抄造
し、成型するこによって、上記本発明に係る電気音響変
換用振動板を安価に製造することが出来る。In the method of manufacturing a diaphragm for electroacoustic conversion according to the present invention, the rice hulls remaining after milling are reduced to approximately 1000 to 1%.
By burning in oxygen at 500 ° C., porous ceramic particles (4) containing silicon oxide as a main component are obtained.
Therefore, the porous ceramic particles (4) are
By mixing the pulp fiber (2) with the pulp fiber (2) via (3), forming the pulp fiber (2), and forming the pulp fiber (2), the diaphragm for electroacoustic conversion according to the present invention can be manufactured at low cost.
【００１２】[0012]
【実施例】以下、本発明の一実施例について説明する。
本発明に係る振動板の製造工程においては、先ず、精米
後の籾殻を略１０００乃至１５００℃の酸素中で約１時
間燃焼させる。これによって得られる残留物には、重量
％にて、酸化珪素(ＳiＯ2)：約８０％、炭素(Ｃ)：約１
０％、カリウム(Ｋ)及びその他の不純物：約１０％が含
まれ、該残留物は、多孔質のセラミクスとなる。尚、上
記組成については、出願人が化学分析、電子分光分析及
び電子線マイクロ分析を用いて実際に測定して得たもの
である。An embodiment of the present invention will be described below.
In the manufacturing process of the diaphragm according to the present invention, rice hulls after milled rice are first burned in oxygen at about 1000 to 1500 ° C. for about 1 hour. The residue thus obtained contains about 80% by weight of silicon oxide (SiO 2 ) and about 1% by weight of carbon (C).
0%, potassium (K) and other impurities: about 10%, the residue becomes porous ceramics. The above composition was obtained by actual measurement by the applicant using chemical analysis, electron spectroscopic analysis and electron beam microanalysis.
【００１３】次に、上記残留物を２０〜３０％、紙パル
プＢＫＰ(晒硫酸塩パルプ)を７０〜６０％、ＰＨ８乃至
１０の弱アルカリ性アクリル系樹脂からなるバインダー
を１０％の重量比で叩解、攪拌する。Next, the above-mentioned residue is beaten at a weight ratio of 20 to 30%, paper pulp BKP (bleached sulfate pulp) at 70 to 60%, and a binder made of a weak alkaline acrylic resin having a pH of 8 to 10 at a weight ratio of 10%. And stir.
【００１４】その後、従来と同様の抄紙工程、脱水工
程、成型工程を経て図３に示す如きスピーカ振動板(１)
を完成する。After that, the papermaking process, the dewatering process, and the molding process are performed in the same manner as in the prior art, and the speaker diaphragm (1) shown in FIG.
To complete.
【００１５】図１は、上記工程を経て得られた振動板素
材の組織図を示しており、パルプ繊維(２)はバインダー
(３)によって連結されると共に、パルプ繊維(２)間の空
隙部には、多孔質セラミクス粒(４)が緻密に散在してい
る。FIG. 1 is a diagram showing the structure of a diaphragm material obtained through the above-mentioned steps.
While being connected by (3), porous ceramic particles (4) are densely scattered in the gaps between the pulp fibers (2).
【００１６】下記の表１は、上記本発明に係る振動板と
従来の紙パルプ製振動板(ＢＫＰ１００％)の諸特性を比
較したものである。Table 1 below compares the characteristics of the diaphragm according to the present invention with those of a conventional diaphragm made of paper pulp (BKP 100%).
【表１】 [Table 1]
【００１７】表１から明らかな様に本発明によって、音
速が上昇すると同時に内部損失が増大している。As is clear from Table 1, the present invention increases the sound velocity and simultaneously increases the internal loss.
【００１８】又、図４は、１０cmスピーカにおける本発
明の振動板と従来の振動板の音圧周波数特性を比較した
ものであり、実線(５)で示す本発明の振動板の周波数特
性は、破線(６)で示す従来の振動板の周波数特性に比べ
て、高音域の再生範囲が拡大していることがわかる。FIG. 4 is a graph comparing the sound pressure frequency characteristics of the diaphragm of the present invention and the conventional diaphragm in a 10 cm speaker, and the frequency characteristics of the diaphragm of the present invention indicated by a solid line (5) are as follows. It can be seen that the reproduction range of the high frequency range is expanded as compared with the frequency characteristic of the conventional diaphragm shown by the broken line (6).
【００１９】上記の如く、本発明に係る振動板の製造方
法によれば、精米後の謂わば廃物である籾殻を利用し
て、高ヤング率、低密度、高内部損失のスピーカ振動板
が製造されるから、資源の有効活用の点においても優れ
た効果が得られる。As described above, according to the method for manufacturing a diaphragm according to the present invention, a loudspeaker diaphragm having a high Young's modulus, a low density, and a high internal loss is manufactured using rice hulls, which are so-called wastes after milling. Therefore, excellent effects can be obtained in terms of effective use of resources.
【００２０】又、従来の製造方法と比べて原材料のみが
異なり、製造工程の構成は同一であるから、従来の製造
設備をそのまま利用出来る利点がある。Further, only the raw materials are different from those of the conventional manufacturing method, and the configuration of the manufacturing process is the same. Therefore, there is an advantage that the conventional manufacturing equipment can be used as it is.
【００２１】上記実施例の説明は、本発明を説明するた
めのものであって、特許請求の範囲に記載の発明を限定
し、或は範囲を減縮する様に解すべきではない。又、本
発明の各部構成は上記実施例に限らず、特許請求の範囲
に記載の技術的範囲内で種々の変形が可能である。例え
ば、多孔質セラミクス粒(４)は上記組成のみならず、多
孔質酸化珪素を主成分とするものであれば、他の組成、
成分比も採用可能であり、これによって所望の特性を実
現することが可能となる。The description of the above embodiments is for the purpose of illustrating the present invention and should not be construed as limiting the invention described in the appended claims or reducing the scope thereof. Further, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims. For example, the porous ceramic particles (4) have not only the above composition, but also other compositions as long as they are mainly composed of porous silicon oxide.
Component ratios can also be employed, thereby achieving desired properties.
【００２２】又本発明は、図３の如き駆動源を有するス
ピーカ振動板のみならず、ドロンコーン或いはパッシブ
ラジエータの如き駆動源を有しない振動板にも有効であ
るのは勿論である。The present invention is, of course, effective not only for a speaker diaphragm having a driving source as shown in FIG. 3, but also for a diaphragm having no driving source such as a drone cone or a passive radiator.
【図１】本発明に係る振動板を形成する素材の組織図で
ある。FIG. 1 is an organization diagram of a material forming a diaphragm according to the present invention.
【図２】従来の振動板を形成する素材の組織図である。FIG. 2 is an organization diagram of a material forming a conventional diaphragm.
【図３】スピーカ振動板の断面図である。FIG. 3 is a sectional view of a speaker diaphragm.
【図４】音圧周波数特性を示すグラフである。FIG. 4 is a graph showing sound pressure frequency characteristics.
(１) 振動板 (２) パルプ繊維 (３) バインダー (４) 多孔質セラミクス粒 (1) Diaphragm (2) Pulp fiber (3) Binder (4) Porous ceramic particles
Claims (2)
合物からなるパルプ繊維(２)と、樹脂バインダ(３)と、
酸化珪素を主成分として炭素及びカリウムを含有する多
孔質セラミクス粒(４)とを混合して抄造、成型すること
により、前記樹脂バインダ(３)により連結された前記パ
ルプ繊維(２)間の空隙部に、前記多孔質セラミクス粒
(４)を包埋せしめたことを特徴とする電気音響変換用振
動板。1. A pulp fiber (2) made of a natural fiber, a synthetic fiber or a mixture thereof, a resin binder (3),
A void between the pulp fibers (2) connected by the resin binder (3) is formed by mixing and forming a porous ceramic particle (4) containing silicon oxide as a main component and containing carbon and potassium, followed by molding and molding. In the part, the porous ceramic particles
A diaphragm for electroacoustic conversion, wherein (4) is embedded.
中にて燃焼させることにより、酸化珪素を主成分として
炭素及びカリウムを含有する多孔質セラミック粒(４)を
得る第１の工程と、 天然繊維、合成繊維若しくはこれらの混合物からなるパ
ルプ繊維(２)と、樹脂バインダ(３)と、前記第１の工程
により得られた多孔質セラミクス粒(４)とを混合して抄
造、成型することにより、前記樹脂バインダ(３)により
連結された前記パルプ繊維(２)間の空隙部に前記多孔質
セラミクス粒(４)を包埋せしめた電気音響変換用振動板
を得る第２の工程とを備えることを特徴とする電気音響
変換用振動板の製造方法。2. A first step of burning rice husks in oxygen at about 1000 to 1500 ° C. to obtain porous ceramic particles (4) containing silicon oxide as a main component and containing carbon and potassium; Pulp fiber (2) made of fiber, synthetic fiber or a mixture thereof, resin binder (3), and porous ceramic particles (4) obtained in the first step are mixed to form and form a paper. A second step of obtaining a diaphragm for electroacoustic conversion in which the porous ceramic particles (4) are embedded in voids between the pulp fibers (2) connected by the resin binder (3). A method for manufacturing a diaphragm for electroacoustic conversion, comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3230078A JP2648056B2 (en) | 1991-09-10 | 1991-09-10 | Electroacoustic conversion diaphragm and method of manufacturing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3230078A JP2648056B2 (en) | 1991-09-10 | 1991-09-10 | Electroacoustic conversion diaphragm and method of manufacturing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05236590A JPH05236590A (en) | 1993-09-10 |
| JP2648056B2 true JP2648056B2 (en) | 1997-08-27 |
Family
ID=16902207
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3230078A Expired - Fee Related JP2648056B2 (en) | 1991-09-10 | 1991-09-10 | Electroacoustic conversion diaphragm and method of manufacturing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2648056B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5326640B2 (en) * | 2009-02-19 | 2013-10-30 | パナソニック株式会社 | Speaker diaphragm, speaker using the speaker diaphragm, electronic apparatus and moving means using the speaker |
| CN116572357A (en) * | 2023-05-06 | 2023-08-11 | 江苏中科聚合新材料产业技术研究院有限公司 | Ceramic-based dome material and preparation method thereof |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS606595A (en) * | 1983-06-24 | 1985-01-14 | 新明和工業株式会社 | Safety control device for aerial work vehicles |
| JPS60214195A (en) * | 1984-04-09 | 1985-10-26 | Matsushita Electric Ind Co Ltd | Manufacture of diaphragm for speaker |
| JPH01160879A (en) * | 1987-12-15 | 1989-06-23 | Kanebo Ltd | Production of porous ceramic material |
-
1991
- 1991-09-10 JP JP3230078A patent/JP2648056B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05236590A (en) | 1993-09-10 |
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