Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making named article
Reexamination Certificate
2003-11-10
2004-12-14
McPherson, John A. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making named article
C430S322000, C181S175000, C181S166000
Reexamination Certificate
active
06830876
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
N/A
BACKGROUND OF THE INVENTION
The use of acoustic resistance in transducers and sound channels is well known. In the case of a sound tube, for example, a resistance equal to its characteristic impedance will completely damp the length resonances, leaving a smooth frequency response. This is recently taught, for example, by the inventor in his chapter describing use of dampers entitled (“Earmold Design: Theory and Practice,” Proceedings of 13th Danavox Symposium, pp. 155-174, 1988). In the case of microphones and receivers, acoustic resistance can be used to smooth resonance peaks and improve the sound quality (as described by Killion and Tillman in their paper “Evaluation of High-Fidelity Hearing Aids,” J. Speech Hearing Res., V. 25, pp. 15-25, 1982). In the case of earplugs, acoustic resistance can be used in cooperation with other acoustic elements to produce high fidelity earplugs such as used by musicians in symphony orchestras (as cited in the following: Carlson, 1989, U.S. Pat. No. 4,807,612; Killion, 1989, U.S. Pat. No. 4,852,683; Killion, Stewart, Falco, and Berger, 1992, U.S. Pat. No. 5,113,967).
One problem, however, with available acoustic resistors, commonly called dampers or damping elements, is their cost. When produced with adequately tight tolerance such as to +/−20% or better, the most popular damping elements (Knowles BF-series plugs, Carlson and Mostardo, 1976, U.S. Pat. No. 3,930,560) cost $0.60 each even in very high quantities. This has been relatively stable over the life of the U.S. Pat. No. 3,930,560 and has been independent of whether the actual damping element is a cloth mesh, perforated metal (typically electroformed), or the like.
Another problem with available acoustic resistors is their design.
FIG. 1
illustrates a typical early prior art acoustic resistor design. Resistor (damper)
100
is comprised of a flat piece of cloth (e.g., silk) punched into a cloth disc
101
. Cloth disc
101
is mounted on a flat surface over an acoustic port or tube
103
. Typically, non-corrosive rubber-like adhesive
105
, for example, is used between a bottom surface of cloth disc
101
and a top surface of the structure that forms port or tube
103
. Portions of the adhesive
105
typically wick into areas of the open region of cloth disc
101
, as shown by reference numerals
107
and
109
.
FIGS. 2A and 2B
illustrate a later prior art acoustic resistor design.
FIG. 2A
is a side view of a damper
200
, which is comprised of a flat piece of metal
203
that has perforated holes
205
in the middle. The perforated holes
205
form the open region of the damper
201
.
FIG. 2B
is another review of the damper of FIG.
2
A. As can be seen, the damper
201
is generally comprised of a perforated center section
207
(i.e., the open region) and a solid outer ring
209
.
Like damper
100
, damper
200
is mounted on a flat surface over an acoustic tube or port (not shown). Adhesive is likewise used between a surface of the solid outer ring
209
and a top surface of the structure that forms the tube or port. Again, portions of the adhesive wick into the perforated center section
207
, partially deforming the open region of the damper
200
.
In both cases, this wicking effect causes a change in the diameter of the open region of the damper, which consequently causes a change in the resistance of the damper. A 2% change in the diameter of the open region of the damper causes an approximately 4% change in the resistance of the damper. Because the diameter of the port or tube of prior art devices was typically large, however, changes in the diameter of the damper as such had at least a tolerable adverse effect on damper performance.
As the port and tube diameters of hearing improvement and audiometric devices become smaller and smaller, however, the adverse effect of adhesive wicking becomes more pronounced. In order to obtain tight tolerances of resistance values as port and tube diameters decrease, it is desirable to more tightly control the open region of the damper by eliminating adhesive wicking. On the other hand, in order to provide inexpensive assembly, adhesive is generally used. The combination of small dampers and the use of adhesive, however, causes highly variable results.
Further limitations and disadvantages of conventional and traditional systems will become apparent to one of skill in the art through comparison of such systems with the present invention set forth in the remainder of the present application with reference to the drawings.
BRIEF SUMMARY OF THE INVENTION
The problems and drawbacks of the prior art are addressed by the damper of the present invention. The damper comprises a mesh material and a mounting material that is attached to the mesh material. The mounting material defines an open region of the mesh material through which sound is transmitted. The mounting material has a mounting surface that is located on a different plane than the mesh material. This configuration enables adhesive to be used between the mounting surface of the damper and a corresponding mounting surface surrounding an acoustic opening, without effecting the resistance of the mesh material in the open region.
The mesh material may be, for example, cloth, metal, polyester, nylon or silk. The mounting material may be emulsion or double-sided tape, for example.
In an emulsion embodiment, the damper may be manufactured by applying a photosensitive emulsion over the mesh material and exposing the emulsion through a photographic mask. The exposed emulsion is washed away, leaving an open region of mesh and a surround of emulsion. The surround of emulsion (and mesh) is then mechanically punched to generate a “doughnut” damper, or any other desired shape, having an open region of mesh defined by surrounding emulsion.
In a double-sided tape embodiment, the damper may be manufactured by applying a sheet of perforated double-sided tape to a mesh material. The double-sided tape surrounding the perforation is then mechanically punched to generate a finished damper product (after removal of the double-sided tape backing), having an open region of mesh defined by surrounding double-sided tape.
Other aspects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
REFERENCES:
patent: 953557 (1910-03-01), Shepart
patent: 3930560 (1976-01-01), Carlson et al.
patent: 4349082 (1982-09-01), Gastmeier
patent: 4852683 (1989-08-01), Killion
patent: 5511296 (1996-04-01), Dias et al.
patent: 6029769 (2000-02-01), Tichy
Haapapuro Andrew J.
Killion Mead C.
Chacko-Davis Daborah
Etymotic Research Inc.
McAndrews Held & Malloy Ltd.
McPherson John A.
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