U.S. patent application number 09/862069 was filed with the patent office on 2001-12-06 for semiconductor digital loudspeaker array.
Invention is credited to Thomas, David R..
Application Number | 20010048123 09/862069 |
Document ID | / |
Family ID | 26902280 |
Filed Date | 2001-12-06 |
United States Patent
Application |
20010048123 |
Kind Code |
A1 |
Thomas, David R. |
December 6, 2001 |
Semiconductor digital loudspeaker array
Abstract
A high performance unary digital loudspeaker system is
disclosed; providing cost-effective and efficient performance, and
providing the option to integrate multiple speaker elements or
other related circuitry, and comprising a semiconductor substrate
(102), an electrode (104) disposed upon the substrate, an insulator
element (106) disposed upon the electrode forming a frame of
material, an electrically conductive membrane (108) disposed upon
the insulator element so as to form a chamber (110) between the
electrode and the membrane, the membrane having a flexible support
section (112) formed therein, and a control circuit (200) coupled
(114, 116) to the membrane and the electrode, and adapted to
provide a variable potential therebetween.
Inventors: |
Thomas, David R.; (Opio,
FR) |
Correspondence
Address: |
TEXAS INSTRUMENTS INCORPORATED
P O BOX 655474, M/S 3999
DALLAS
TX
75265
|
Family ID: |
26902280 |
Appl. No.: |
09/862069 |
Filed: |
May 21, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60207488 |
May 26, 2000 |
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Current U.S.
Class: |
257/258 |
Current CPC
Class: |
H04R 1/005 20130101 |
Class at
Publication: |
257/258 |
International
Class: |
H01L 029/80 |
Claims
What is claimed is:
1. A unary digital speaker comprising: a substrate; a first
electrically conductive member disposed upon the substrate; an
electrically non-conductive element disposed upon the first
electrically conductive member; a second electrically conductive
member disposed upon the non-conductive element so as to form a
chamber between the first and second electrically conductive
members.
2. The speaker of claim 1 wherein the substrate is a semiconductor
substrate.
3. The speaker of claim 1 wherein the non-conductive element
comprises a plurality of pieces.
4. The speaker of claim 1 wherein the non-conductive element
comprises a single frame of material.
5. The speaker of claim 1 further comprising a flexible support
section adjoining the second electrically conductive member with
the non-conductive element.
6. The speaker of claim 5 wherein the flexible support section is
an independent structure jointly coupled to the second electrically
conductive member and the non-conductive element.
7. The speaker of claim 5 wherein the flexible support section is
formed within the second electrically conductive member.
8. The speaker of claim 1 wherein the first electrically conductive
member is formed of metal.
9. The speaker of claim 1 wherein the second electrically
conductive member is formed of metal.
10. The speaker of claim 1 wherein the chamber comprises a
vacuum.
11. The speaker of claim 1 wherein the chamber comprises a low
pressure cavity.
12. A method of producing a unary digital speaker comprising the
steps of: providing a substrate; disposing a first electrically
conductive member upon the substrate; disposing an electrically
non-conductive element upon the first electrically conductive
member; disposing a second electrically conductive member upon the
non-conductive element, forming a chamber between the first and
second electrically conductive members.
13. The method of claim 12 wherein the step of providing a
substrate further comprises providing a semiconductor
substrate.
14. The method of claim 12 wherein the step of disposing an
electrically non-conductive element further comprises forming the
electrically non-conductive element from a plurality of pieces.
15. The method of claim 12 wherein the step of disposing an
electrically non-conductive element further comprises forming a
single frame of material.
16. The method of claim 12 further comprising the step of providing
a flexible support section adjoining the second electrically
conductive member with the non-conductive element.
17. The method of claim 16 wherein the flexible support section is
formed within the second electrically conductive member.
18. The method of claim 12 wherein the forming of a chamber further
comprises forming a vacuum.
19. The method of claim 12 wherein the forming of a chamber further
comprises forming a low pressure cavity.
20. A semiconductor digital loudspeaker array comprising: a
semiconductor substrate; an electrode disposed upon the substrate;
an insulator element disposed upon the electrode forming a frame of
material; an electrically conductive membrane disposed upon the
insulator element so as to form a low pressure chamber between the
electrode and the membrane, having a flexible support section
formed therein; and a control circuit coupled to the membrane and
the electrode, and adapted to provide a variable potential
therebetween.
Description
BACKGROUND OF THE INVENTION
[0001] Conventional analog loudspeakers generally rely on the
motion of a diaphragm stimulated by some type of motor to reproduce
a desired sound. All, or part, of the diaphragm is stimulated in
correspondence to an analog electrical signal, typically
representing the instantaneous sound pressure that a listener
should hear. Analog loudspeakers typically suffer a number of
inherent limitations involving, for example, high frequency
distortion, non-linearity, and poor power efficiency. Although some
solutions have attempted to address these limitations, such
solutions have introduced problems of their own, such as
non-uniform frequency response, imbalance, phase distortions, power
loss and reduction, and increased costs and complexity. Thus,
generally, analog loudspeakers have been considered highly
inefficient.
[0002] The prevalence of high quality digital audio material, and
trends in electronic equipment to minimize power consumption for
miniaturization and operation from small batteries, have rendered
analog loudspeakers somewhat inadequate. Also, conventional analog
systems typically require a digital to analog converter (DAC) at
some point in the system for the reproduction of digital source
material. DACs introduce noise and distortion that adds to that
already present in the system, and also add extra cost.
[0003] Previously, attempts were made to develop binary digital
loudspeakers overcoming the limitations of analog loudspeakers.
Such binary digital loudspeakers typically produced marginal
improvement over analog systems, but still suffered to some extent
from all the limitations previously described, and in some cases
introduced further limitations and costs. Many such attempts relied
on ratiometric division of a diaphragm or coil turns to correspond
to digital bit patterns. These systems suffered from problems with
precision and skew resulting in undesired transients and added
distortion.
[0004] Most conventional digital loudspeaker systems have assumed
that binary digital code was the digital signal medium from the
input of the device through to the output transducers. Such systems
typically suffer from switching transient problems or level change
errors, affecting system accuracy and causing large distortion
components. Attempts to address such complications with extreme
mechanical precision result in high manufacturing costs, and may
not achieve the precision required.
[0005] Still further attempts were made to produce unary digital
loudspeakers, overcoming some of the problems associated with and
having higher electrical to sound efficiency than conventional
binary digital loudspeakers, and requiring less mechanically
accurate speaker structures. Conventional unary speakers generally
have a characteristic of being fully "on" when any voltage or
current pulse was applied to the speaker, or fully "off" in the
absence of any pulse. Typically, conventional unary speaker systems
or arrays required a large number of speakers or speaker elements.
These approaches were inefficient from both a size and performance
perspective. Other conventional systems utilizing piezoelectric
transducers and conventional mechanical components commonly
utilized separate speakers and drive circuits, reducing system
performance and increasing system costs.
SUMMARY OF THE INVENTION
[0006] Therefore, a high performance unary digital loudspeaker
system designed without conventional mechanical structures is now
needed; providing cost-effective and efficient performance, and
providing the option to integrate multiple speaker elements or
other related circuitry, while overcoming the aforementioned
limitations of conventional methods.
[0007] The present invention provides a unary semiconductor digital
loudspeaker comprising a substrate, an electrode disposed upon the
substrate, an insulator disposed upon the electrode, and an
electrically conductive membrane disposed upon the insulator and
forming a chamber between the electrode and membrane.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] For a more complete understanding of the features and
advantages of the present invention, reference is now made to the
detailed description of the invention along with the accompanying
figures in which corresponding numerals in the different figures
refer to corresponding parts and in which:
[0009] FIG. 1 is an illustrative diagram of an embodiment of the
present invention; and
[0010] FIG. 2 is an illustrative diagram of another embodiment of
the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0011] While the making and the use of the present invention is
discussed in detail below, it should be appreciated that the
present invention provides many applicable inventive concepts which
can be embodied in a wide variety of specific contexts. The
specific embodiments discussed herein are merely illustrative of
specific ways to make and use the invention, do not delimit the
scope of the invention.
[0012] The present invention recognizes that, using certain
semiconductor processing technology, one can produce high
performance digital loudspeakers without relying on problematic
conventional mechanical structures. Referring now to FIG. 1, a
digital speaker system 100 according to the present invention is
depicted. System 100 comprises a substrate 102, a bottom electrode
member 104, insulator elements 106, and membrane member 108.
Electrode 104 may comprise metal or other suitable electrically
conductive material, and is attached or coupled to substrate 102
using available semiconductor processing (e.g. deposition).
Elements 106 comprise an electrically insulating or non-conductive
material, and are disposed upon electrode 104 with in a spatially
separate relationship. Alternatively, element 106 may comprise a
single contiguous frame-like structure of material disposed upon
electrode 104, shaped to support membrane 108. Membrane 108 is
suspended over electrode 104 by elements 106, and elements 106 are
so configured, such that chamber 110 is formed between membrane 108
and electrode 104. Membrane 108 is formed of electrically
conductive material, such as metal. Chamber 110 may be either a
vacuum or low-pressure cavity. Chamber 110 thus have very little
resistance to movement of membrane 108, resulting in high
electrical to audio efficiency. Membrane 108 is formed such that
flexible support sections 112 adjoin the inner surface of membrane
108 around the perimeter of chamber 110 with the insulators 106,
providing stable flexion and movement of membrane 108. Each support
112 may comprise an integral recess formed in membrane 108, or may
comprise a separate component coupled jointly to membrane 108 and
insulator 106. Leads 114 and 116 couple membrane 108 and electrode
104, respectively, to control circuitry. Using such control
circuitry to apply a voltage between membrane 108 and electrode
104, one can efficiently move membrane 108 in relation to electrode
104, providing the fully on/fully off characteristics required of a
unary digital speaker without the limitations inherent in prior
approaches.
[0013] Assembly 100 can be formed using any suitable semiconductor
processes, alone or in combination, such as silicon micro machining
techniques, multi-step mask processes, deposition or etching.
Utilizing the design of the present invention, one may efficiently
produce an array of unary speakers on a single substrate. One might
also incorporate related circuitry, such as the circuitry necessary
to control the voltage applied to the individual speakers, or other
decode logic necessary to determine which speaker(s) should be
activated at a given time. The present invention thus requires
lower interconnect overhead than previous approaches, providing
higher system reliability, reduced drive current and lower power
consumption. FIG. 2 depicts one such example, wherein assembly 100
is coupled to a control circuit 200.
[0014] As depicted in FIG. 2, control circuit comprises a
transistor 202 and a resistor 204. The base of transistor 202 is
coupled to an input 206, the collector of transistor 202 is coupled
to lead 114, and the emitter of transistor 202 is coupled jointly
to a first end of resistor 204 and to lead 116. A second end of
resistor 204 is coupled to ground. Voltage at input 206 may be
adjusted to vary the potential between membrane 108 and electrode
104, producing desired sound waves.
[0015] Utilizing the design of the present invention, one may also
efficiently interconnect a number of integrated array elements to
form a speaker array of any desired size. The present thus provides
means to efficiently construct a single chip audio unit (e.g. fully
integrated hearing aid or active noise canceling ear plugs). The
use of semiconductor process construction provides significant cost
advantages over previous separate mechanical electrical
processing.
[0016] While this invention has been described in reference to
illustrative embodiments, this description is not intended to be
construed in a limiting sense. Various modifications and
combinations of the illustrative embodiments, as well as other
embodiments of the invention, will be apparent to persons skilled
in the art upon reference to the description. The teachings and
concepts of the present invention may be applied using a variety of
semiconductor processes, or to produce a variety of acoustic
components and systems. Thus, the principles of the present
invention are practicable in a number of applications and
technologies. It is therefore intended that the appended claims
encompass any such modifications or embodiments.
* * * * *