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Development of New Diaphragm Materials for Loudspeakers

Research Project

Project/Area Number 63850064
Research Category

Grant-in-Aid for Developmental Scientific Research

Allocation TypeSingle-year Grants
Research Field 電子通信系統工学
Research InstitutionMiyagi National College of Technology

Principal Investigator

ONO Takayuki  Miyagi National College of Technology, Department of General Education, Professor, 一般科目, 教授 (30005342)

Co-Investigator(Kenkyū-buntansha) MATSUURA Makoto  Miyagi National College of Technology, Department of Basic and Specialized Educa, 基礎専門科目, 教授 (40042262)
TANNO Choichi  Miyagi National College of Technology, Department of Materials Science and Engin, 材料工学科, 教授 (50042247)
Project Period (FY) 1988 – 1989
Project Status Completed (Fiscal Year 1989)
Budget Amount *help
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1989: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1988: ¥1,600,000 (Direct Cost: ¥1,600,000)
KeywordsDiaphragm for loudspeaker / Composite materials / Electrostatic attraction / Anode oxidation of aluminum / Expanded graphite / Mica / Specific modulus / Loss tangent / 複合体 / アルミニウム板 / 陽極酸化 / ポリメタクリル酸メチル / スピーカー振動板 / アルミニウム粉 / アルミニウム箔 / メタクリル酸メチル / 酸化処理 / 重合反応 / 複合化
Research Abstract

Acoustic characteristics of loudspeakers are largely influenced by physical properties of diaphragm materials. The frequency band is in proportion to specific modulus E/rho and the harmonic distortion decrease with increasing loss tangent eta value. Acoustic reproduction characteristics of loudspeaker is improved by enlargement of E/rho and eta value.
The purpose of this investigation is development of new diaphragm materials for loudspeakers made of polymer-inorganic substance or polymer-metal composite materials. These composites were prepared by means of polymerization method, polymer emulsion method and anode oxidation method of light metal. Polymerization of vinyl monomers was carried out in the presence of inorganic, metal or organic powders in aqueous medium using various initiators, and powders encapsulated with polymer were readily obtained. Furthermore, polymethyl methacrylate emulsion particles was tightly deposited onto various fillers such as mica, graphites, carbon fiber, wood powder etc. by considering electrostatic attraction between filler surface and terminal ionic groups of polymer. These composite materials could be directly molded and accurately formed into any shape. On the other hand, aluminum thin plate was oxidized by the electrolytic oxidation and oxide film on anode was combined with various polymers. These composite materials showed a high E/rho and eta value, especially in mica, expanded graphite and oxide film of aluminum. Frequency response characteristics of speakers using a diaphragm made of the expanded graphite polymethyl methacrylate composite film was flat and harmonic distortion was lower in the high frequency range.
From results, these composite materials were found out to be excellent new diaphragm materials for Hi-Fi loudspeakers.

Report

(3 results)
  • 1989 Annual Research Report   Final Research Report Summary
  • 1988 Annual Research Report

URL: 

Published: 1988-04-01   Modified: 2016-04-21  

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