Diaphragm for dynamic microphones and methods of manufacturing the same

• US 5,259,036 A
• Filed: 07/22/1991
• Issued: 11/02/1993
• Est. Priority Date: 07/22/1991
• Status: Expired due to Fees

• Current Assignee: Shure Incorporated
• Original Assignee: Shure Brothers Incorporated
• Inventors: Seeler, Charles E.
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): Le, Huyen D.
• Application Number:
  US07/734,213
• Time in Patent Office: 834 Days
• Field of Search: 381/202, 381/203, 381/204, 181/167, 181/170, 428/492, 428/64, 428/523, 428/517
• US Class Current: 381/426
• 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
• CPC Class Codes: Y10T 156/1052 with cutting, punching, tearing or severing

Abstract

A diaphragm for microphones having a laminate structure which imparts damping characteristics to the diaphragm is disclosed. The laminate comprises upper and lower resilient layers composed of a plastic film. The upper and lower layers constrain a center layer composed of an elastomeric material having a high dissipation of vibratory shear motion. Manufacturing techniques for making such diaphragms are disclosed.

Claims

1. A diaphragm for an electroacoustic transducer having a laminar structure, said laminar structure comprising:

first and second outer layers each composed of a resilient (material) plastic film; and

a center layer composed of (an elastomeric material) rubber having a high dissipation of vibratory shear motion bonded to said first and second outer layers, thereby imparting damping characteristics to said diaphragm, said first and second outer layers being between 60 and 150 micro-inches in thickness, and the average thickness of the laminate structure being between 900 to 2,000 micro-inches in thickness.

2. The diaphragm as claimed in claim 1 wherein said diaphragm is installed in a microphone.

3. The diaphragm as claimed in claim 1 wherein said plastic film is a polyethylene terephthalate film (and said material forming said center layer is rubber).

4. The diaphragm as claimed in claim 1 wherein said first and second outer layers are approximately 120 micro-inches in thickness and said average thickness of said diaphragm is approximately 1,300 micro-inches.

5. The diaphragm as claimed in claim 4 wherein said rubber is a cured polyacrylic rubber.

6. The diaphragm as claimed in claim 4 wherein said rubber is a cured butyl rubber.