Acoustic vibration plate

• US 5,473,121 A
• Filed: 05/15/1992
• Issued: 12/05/1995
• Est. Priority Date: 05/16/1991
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Uryu, Masaru
• Primary Examiner(s): Dang, Khanh
• Application Number:
  US07/883,547
• Time in Patent Office: 1,299 Days
• Field of Search: 181/167, 181/169, 181/170, 428/200, 428/245, 428/265, 428/252, 428/272, 106/163.1
• US Class Current: 181/169
• CPC Class Codes: H04R 31/003 for diaphragms or their outer suspension
• CPC Class Codes: H04R 7/125 comprising a plurality of superposed layers in contact
• CPC Class Codes: H04R 7/127 dome-shaped

Abstract

An acoustic diaphragm employed in a speaker or the like and a method for producing the acoustic diaphragm are disclosed. A diaphragm substrate is a diaphragm exhibiting air permeability such as a paper diaphragm. The substrate is processed with filling by microfibrilated pulp. For filling, the substrate is immersed in the liquid dispersion of the microfibrilated pulp and the pulp is deposited on the substrate under suction. When the microfibrilated pulp is deposited on the substrate under suction, any voids present in the substrate are closed by the microfibrilated pulp so that air tightness is improved without lowering the sound quality or detracting from desirable properties of the diaphragm, such as low density, high toughness and low losses.

Claims

1. An acoustic diaphragm comprising:

a paper substrate exhibiting air permeability and having a surface, said substrate having voids therein; and

a separate layer being formed of microfibrilated pulp and being deposited on the surface of said substrate, said separate layer filling said voids in the paper substrate.

2. An acoustic diaphragm as claimed in claim 1 wherein the layer of microfibrilated pulp deposited on said substrate is formed of paper.

3. An acoustic diaphragm comprising:

a substrate being formed of air permeable paper and being shaped in the form of a desired completed diaphragm with a first surface, said substrate having voids therein; and

a separate layer being formed of microfibrilated pulp and being deposited on said first surface of the substrate, said separate layer filling said voids in the air permeable substrate.

4. An acoustic diaphragm according to claim 3, wherein said layer has a thickness of at least 5 μ

m.