Method of manufacturing a wafer fabricated electroacoustic transducer

• US 6,308,398 B1
• Filed: 12/10/1999
• Issued: 10/30/2001
• Est. Priority Date: 09/06/1996
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Corporation
• Inventors: Beavers, Bob Ray
• Primary Examiner(s): Young, Lee
• Assistant Examiner(s): TUGBANG, ANTHONY D
• Application Number:
  US09/459,223
• Time in Patent Office: 690 Days
• Field of Search: 29/254.1, 29/253.5, 295/94, 295/95, 295/57, 298/86, 298/29, 294/12, 381/174, 381/191, 381/113, 381/116, 310/322, 310/324, 310/369
• US Class Current: 29/594
• CPC Class Codes: H04R 19/04 Microphones H04R19/01 takes precedence
• CPC Class Codes: H04R 31/00 Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor manufacture of microstructural arrangements of deformable or non-deformable structures in general B81C1/00182
• CPC Class Codes: H04R 31/006 Interconnection of transducer parts of diaphragm and outer suspension by moulding H04R31/003
• CPC Class Codes: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/43 Electric condenser making
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/49226 Electret making
• CPC Class Codes: Y10T 29/49789 Obtaining plural product pieces from unitary workpiece

Abstract

A method is disclosed for simultaneously producing a plurality of capacitive electroacoustic transducers. The method comprises forming a plurality of electrically insulative substrates by cutting circular slots to an insulating wafer. Each slot is interrupted by at least two tabs connecting a circular area with the remainder of the wafer. The conductive diaphragms are supported on diaphragm mounting rings disposed upon the substrate, spaced from a first electrode. The mounting rings space the diaphragm from the electrode to define a capacitor operative to convert electrical and acoustical signals.

Claims

1. A method of simultaneously producing a plurality of capacitive electroacoustic transducers comprising the steps of:

(a) forming a plurality of electrically insulative substrates by cutting a plurality of circular slots through a wafer comprising an electrically insulating material, each circular slot being interrupted by at least two tabs connecting a circular area enclosed by the circular slot and constituting the substrate, with a remainder of the wafer, wherein the tabs are breakable so as to release the substrate from the remainder of the wafer;

(c) forming a plurality of conductive diaphragms constituting respective second electrodes of each transducer, each diaphragm being deflectable in relation to a respective first electrode;

(d) forming a plurality of diaphragm mounting rings of electrically conductive material, each diaphragm mounting ring disposed about the periphery of the top surface of the substrate and separated from the first electrode, each diaphragm mounting ring being thicker than the first electrode by an amount corresponding to a desired separation between the diaphragm and the first electrode; and

(e) attaching the diaphragms to the respective diaphragm mounting rings to separate the first and second electrodes in electrical and physical spaced relationship so as to constitute a capacitor thereat, such that an electric field formed between the first and second electrodes varies in relationship with deflections of the second electrode to permit conversion between electrical and acoustic signals.

2. The method of claim 1, wherein the steps of forming a plurality of conductive diaphragms and attaching the diaphragms to the respective diaphragm mounting rings comprise the steps of:

(a) stretching a single sheet of a material comprising a material making up the diaphragm to a desired tension;

(b) placing the stretched sheet of material onto the wafer such that portion of the sheet comes into contact with each of the diaphragm mounting rings disposed on the wafer;

(c) bonding the portion of the stretched sheet of material contacting each diaphragm mounting ring to each said ring, respectively; and

(d) cutting away excess portions of the stretched sheet existing outside an outer edge of each diaphragm mounting ring.