U.S. patent application number 10/826537 was filed with the patent office on 2004-10-21 for method and apparatus for localized delivery of audio sound for enhanced privacy.
Invention is credited to Cheung, Kwok Wai, Thomas, C. Douglass, Tong, Peter P..
Application Number | 20040208324 10/826537 |
Document ID | / |
Family ID | 33303910 |
Filed Date | 2004-10-21 |
United States Patent
Application |
20040208324 |
Kind Code |
A1 |
Cheung, Kwok Wai ; et
al. |
October 21, 2004 |
Method and apparatus for localized delivery of audio sound for
enhanced privacy
Abstract
A directional audio apparatus that provides directional delivery
of audio output is disclosed. The audio output is targeted to those
one or more persons desirous of hearing the audio output.
Consequently, other persons not desirous of hearing the audio
output do not receive substantial amounts of the audio output and
thus are less disturbed by the unwanted audio sounds. In one
embodiment, the directional audio apparatus includes a directional
speaker, whose audio output is generated through ultrasonic
signals. The directional speaker includes a number of speaker
elements. A number of the attributes of the audio output can be
controlled, either by a user or by monitored measurements. Such
attributes include the beam width, the beam direction, the degree
of isolation or privacy, and the volume of the audio outputs. The
audio output can also be personalized or modified according to the
audio conditions of the surroundings of the apparatus. To control
these attributes or characteristics, a number of approaches can be
used. For example, the surface of the speaker can be segmented or
curved, the ultrasonic frequencies can be changed, the phases to
individual speaker elements can be adjusted, or the path lengths of
the ultrasonic waves from the emitting surface of the speaker can
be elongated before the audio output emits into free space. Also,
more than one directional speaker can be used to generate stereo
effects.
Inventors: |
Cheung, Kwok Wai; (Hong
Kong, CN) ; Tong, Peter P.; (Mountain View, CA)
; Thomas, C. Douglass; (Campbell, CA) |
Correspondence
Address: |
IPVENTURE, INC.
5150 EL CAMINO REAL
SUITE A-22
LOS ALTOS
CA
94022
US
|
Family ID: |
33303910 |
Appl. No.: |
10/826537 |
Filed: |
April 15, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60462570 |
Apr 15, 2003 |
|
|
|
60469221 |
May 12, 2003 |
|
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|
60493441 |
Aug 8, 2003 |
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Current U.S.
Class: |
381/77 ;
381/79 |
Current CPC
Class: |
H04M 1/19 20130101; H04R
25/405 20130101; H04R 2201/401 20130101; H04M 1/0214 20130101; H04M
1/605 20130101; H04M 1/6091 20130101; H04R 1/403 20130101; H04R
25/554 20130101; H04H 20/61 20130101; H04H 20/72 20130101; H04R
2217/03 20130101; H04S 3/00 20130101; H04S 1/00 20130101; H04R
2201/023 20130101; H04M 1/03 20130101; H04R 2225/55 20130101; H04R
27/00 20130101 |
Class at
Publication: |
381/077 ;
381/079 |
International
Class: |
H04B 003/00; H04B
005/00 |
Claims
What is claimed is:
1. A directional audio delivery apparatus for a home entertainment
system, comprising: a set-top box that receives incoming encoded
signals and provides decoded audio signals for use by the home
entertainment system; audio conversion circuitry that produces
ultrasonic signals based on the decoded audio signals provided by
said set-top box; and a directional speaker that outputs an
ultrasonic output based on the ultrasonic signals.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority of: (i) U.S. Provisional
Patent Application No. 60/462,570, filed Apr. 15, 2003, and
entitled "WIRELESS COMMUNICATION SYSTEMS OR DEVICES, HEARING
ENHANCEMENT SYSTEMS OR DEVICES, AND METHODS THEREFOR," which is
hereby incorporated herein by reference; (ii) U.S. Provisional
Patent Application No. 60/469,221, filed May 12, 2003, and entitled
"WIRELESS COMMUNICATION SYSTEMS OR DEVICES, HEARING ENHANCEMENT
SYSTEMS OR DEVICES, DIRECTIONAL SPEAKER FOR ELECTRONIC DEVICE,
PERSONALIZED AUDIO SYSTEMS OR DEVICES, AND METHODS THEREFOR," which
is hereby incorporated herein by reference; and (iii) U.S.
Provisional Patent Application No. 60/493,441, filed Aug. 8, 2003,
and entitled "WIRELESS COMMUNICATION SYSTEMS OR DEVICES, HEARING
ENHANCEMENT SYSTEMS OR DEVICES, DIRECTIONAL SPEAKER FOR ELECTRONIC
DEVICE, AUDIO SYSTEMS OR DEVICES, WIRELESS AUDIO DELIVERY, AND
METHODS THEREFOR," which is hereby incorporated herein by
reference.
[0002] This application is also related to: (i) U.S. patent
application Ser. No. ______, filed concurrently, and entitled,
"DIRECTIONAL WIRELESS COMMUNICATION SYSTEMS," which is hereby
incorporated herein by reference; (ii) U.S. patent application Ser.
No. ______, filed concurrently, and entitled, "DIRECTIONAL HEARING
ENHANCEMENT SYSTEMS," which is hereby incorporated herein by
reference; (iii) U.S. patent application Ser. No. ______, filed
concurrently, and entitled, "DIRECTIONAL SPEAKER FOR PORTABLE
ELECTRONIC DEVICE," which is hereby incorporated herein by
reference; and (iv) U.S. patent application Ser. No. ______, filed
concurrently, and entitled, "METHOD AND APPARATUS FOR WIRELESS
AUDIO DELIVERY," which is hereby incorporated herein by
reference.
FIELD OF THE INVENTION
[0003] The present invention relates to audio systems and, more
particularly, to audio output for audio systems with enhanced
privacy.
BACKGROUND OF THE INVENTION
[0004] Audio systems provide audio sounds to one or more users.
Audio systems, for example, include stereo systems, DVD players,
VCRs, and televisions. Typically, these audio systems utilize one
or more speakers to provide audio sounds to a wide area. For
example, an audio system can be internal to a building (e.g.,
house) and produce audio sounds from its speakers provided in a
particular room. Although the audio sounds are generated in the
particular room that contains the speakers, the audio sounds can
permeate to other adjoining rooms. The availability of audio sounds
anywhere in the particular room and other adjoining rooms is
beneficial if other persons in these rooms desire to hear the audio
sounds. Unfortunately, in numerous occasions, the other persons in
these rooms can find the audio output to be quite annoying. In
effect, to these others, the unwanted audio sounds are a form of
noise pollution.
[0005] Today, there are no satisfactory solutions to reduce such
noise pollution. The person (or persons) desirous of hearing the
audio sounds can reduce the volume of the audio sounds or close
openings (e.g., doors) to the adjoining rooms. These approaches are
of limited usefulness as audio sounds can pass through doors and
walls. Also, reducing volume may not be acceptable by the person
desiring to hear the audio sounds. Alternatively, headsets, each
with one or a pair of speakers, can be used. However, wearing a
headset can create its own problem. For example, wearing a headset
substantially limits the user's ability to hear other sounds. When
more than a single person wants to hear the audio sounds, often
they also prefer to simultaneously interact with each other, or
otherwise hear other sounds. Moreover, the use of a headset usually
means only one person can hear the audio sounds.
[0006] Thus, there is a need for improved approaches to providing
audio sounds to desirous persons while reducing disturbance to
other persons not desirous of hearing the audio sounds.
SUMMARY OF THE INVENTION
[0007] The invention pertains to a directional audio delivery
device for an audio system. The audio delivery device provides
directional delivery of audio output for the audio system. The
generated audio output is substantially confined in one or more
beams, each with a beam width. The output is targeted to one or
more persons who would like to hear the audio output. In one
embodiment, these one or more persons can also change a number of
attributes of each beam, such as the direction and the width of,
and the distance covered by, the beam(s), as desired. Consequently,
other persons not desirous of hearing the audio output, can only
hear a substantially lower level of the audio output, and thus are
less disturbed by the unwanted audio sounds.
[0008] The audio system with the directional audio delivery device
can be known as a directional audio apparatus. In one embodiment,
the audio delivery device includes a directional speaker. In one
exemplary configuration, the directional audio delivery device is
in a set-top box that is electrically coupled to the audio system.
In another exemplary configuration, the audio delivery device is in
the audio system.
[0009] In one embodiment, a number of attributes of the audio
outputs can be adjusted. For example, the propagation direction of
the beam can be altered by changing the position of the speaker. As
another example, the speaker can have a curved surface, which can
also be segmented, to control the beam width and/or the beam
direction. The audio output is embedded in or generated from
ultrasonic signals. The frequency of the ultrasonic signals can be
adjusted continuously or discreetly to modify the width of the beam
and the distance covered by the beam. The speaker can have many
speaker elements, such as bimorphs. The phases to the elements can
be controlled to, for example, change the beam width. In one
embodiment, these adjustments can be activated by a user using a
remote control. In another embodiment, adjustments can be made
automatically based on, for example, the location of the user. The
output from the directional speaker can be confined in an enclosure
to increase the path length of the beam before emitting into free
space. This approach can reduce potential hazards, if any, of high
power ultrasonic signals. Also, more than one directional speaker
can be used to create stereo effects.
[0010] The invention can be implemented in numerous ways, including
as a method, system, device, apparatus, and a computer readable
medium.
[0011] Other aspects and advantages of the invention will become
apparent from the following detailed description taken in
conjunction with the accompanying drawings which illustrate, by way
of example, the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The invention will be readily understood by the following
detailed description in conjunction with the accompanying drawings,
wherein like reference numerals designate like structural elements,
and in which:
[0013] FIG. 1 is a block diagram of a directional audio delivery
device coupled to an audio system according to one embodiment of
the invention.
[0014] FIG. 2A is a block diagram of a directional audio delivery
device according to one embodiment of the invention.
[0015] FIG. 2B is a block diagram of a directional audio delivery
device according to another embodiment of the invention.
[0016] FIG. 3A is a diagram illustrating a representative
arrangement suitable for use by different embodiments of the
invention.
[0017] FIG. 3B is a diagram of a representative building layout
illustrating one application of the present invention.
[0018] FIG. 4 is a flow diagram of directional audio delivery
processing according to an embodiment of the invention.
[0019] FIG. 5 shows examples of attributes of the constrained audio
output according to the invention.
[0020] FIG. 6 is another representative building layout
illustrating one application of the present invention.
[0021] FIG. 7 is a flow diagram of directional audio delivery
processing according to another embodiment of the invention.
[0022] FIG. 8A is a flow diagram of directional audio delivery
processing according to yet another embodiment of the
invention.
[0023] FIG. 8B is a flow diagram of an environmental accommodation
process according to one embodiment of the invention.
[0024] FIG. 8C is a flow diagram of audio personalization process
according to one embodiment of the invention.
[0025] FIG. 9A is a perspective diagram of an ultrasonic transducer
according to one embodiment of the invention.
[0026] FIG. 9B is a diagram that illustrates the ultrasonic
transducer with its beam being produced for audio output according
to an embodiment of the invention.
[0027] FIGS. 9C-9D illustrate two embodiments of the invention
where the directional speakers are segmented.
[0028] FIGS. 9E-9G shows changes in beam width based on different
carrier frequencies according to an embodiment of the present
invention.
[0029] FIGS. 10A-10B are diagrams of two embodiments of the
invention where the directional speakers have curved surfaces to
expand the beam.
[0030] FIG. 10C shows beam expansion based on a convex reflector
according to an embodiment of the invention.
[0031] FIGS. 11A-11B show two embodiments of the invention whose
directional speakers have curved surfaces that are segmented.
[0032] FIGS. 12A and 12B are perspective diagrams of audio systems
with directional audio delivery devices in a set-top-box
environment according to different embodiments of the present
invention.
[0033] FIG. 13 is a perspective diagram of a remote control device
according to one embodiment of the invention.
[0034] FIGS. 14A-14B show two embodiments of the invention with
directional audio delivery devices that allow ultrasonic signals to
bounce back and forth before emitting into free space.
[0035] FIG. 15 shows two directional audio delivery devices spaced
apart to generate stereo effects according to one embodiment of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0036] The invention pertains to a directional audio delivery
device for an audio system. The audio system can be a stereo
system, a DVD player, a compact disc player, a music amplifier or a
musical instrument, a VCR, a television, a home-entertainment
system, or other audio system. The audio system typically delivers
audio output based on, or pertaining to, certain audio signals.
These audio signals can be generated by the audio system, or they
can be transmitted to and received by the audio system. The
reception by the audio system can be wireless or wireline, such as
through cables. Without the directional audio delivery device, the
audio system produces audio sound for the benefit of any persons in
its general vicinity. The directional audio delivery device
converts the audio signals into directional audio output that is
substantially confined within a beam having a beam width. The
directional audio output is targeted to one or more persons who
would like to hear the audio output. In one embodiment, these one
or more persons can also control a number of attributes of the
beam. Other persons in the same vicinity who are not desirous of
hearing the audio output, would only hear a substantially lower
level of the audio output. Hence, they are less disturbed by the
unwanted audio sounds.
[0037] The audio system with its corresponding directional audio
delivery device can be known as a directional audio apparatus. The
directional device can be incorporated into the audio system, or
can be confined in a separate housing, such as in a set-top box.
The set-top box can be wired or wirelessly coupled to the audio
system. In this embodiment, if the corresponding audio signals are
not generated by the audio system, but are received externally, the
audio signals can be received either by the set-top box or by the
audio system.
[0038] Embodiments of the invention are discussed below with
reference to FIGS. 1-15. However, those skilled in the art will
readily appreciate that the detailed description given herein with
respect to these figures is for explanatory purposes as the
invention extends beyond these limited embodiments.
[0039] FIG. 1 is a block diagram of a directional audio apparatus
100 with an audio system 102 and a directional audio delivery
device 104, according to one embodiment of the invention.
[0040] FIG. 2A is a block diagram of a directional audio delivery
device 200 according to one embodiment of the invention. The
directional audio delivery device 200 is, for example, suitable for
use as the directional audio delivery device 104 illustrated in
FIG. 1.
[0041] The directional audio delivery device 200 includes audio
conversion circuitry 202 and a directional speaker 204. The audio
conversion circuitry 202 receives audio signals (Audio-In). The
reception can be from the audio system 102, or can be from another
device. The audio signals can be, for example, electrical signals
from the audio system 102, or audio waves wirelessly transmitted to
be received by the audio conversion circuitry 202. The received
audio signals can then be pre-processed, and are then converted
into ultrasonic signals that are supplied to the directional
speaker 204. In one embodiment, the directional speaker 204 is an
ultrasonic speaker that produces ultrasonic output to generate
audio output. The ultrasonic output carries the audio output to be
delivered in a directionally constrained manner. The directional
speaker 204 thus allows the audio output to be directionally
constrained and delivered to desired areas.
[0042] FIG. 2B is a block diagram of a directional audio delivery
device 220 according to another embodiment of the invention. The
directional audio delivery device 220 is, for example, suitable for
use as the directional audio delivery device 104 illustrated in
FIG. 1.
[0043] The directional audio delivery device 220 includes audio
conversion circuitry 222, a beam-attribute control unit 224 and a
directional speaker 226. The audio conversion circuitry 222
converts the received audio signals into ultrasonic signals. The
directional speaker 226 receives the ultrasonic signals and
produces an audio output. The beam-attribute control unit 224
controls one or more attributes of the audio output.
[0044] One attribute can be the beam direction. The beam-attribute
control unit 224 receives a beam attribute input, which in this
example is related to the direction of the beam. This can be known
as a direction input. The direction input provides information to
the beam-attribute control unit 224 pertaining to a propagation
direction of the ultrasonic output produced by the directional
speaker 226. The direction input can be a position reference, such
as a position for the directional speaker 226 (relative to its
housing), the position of a person desirous of hearing the audio
sound, or the position of an external electronic device (e.g.,
remote controller). Hence, the beam-attribute control unit 224
receives the direction input and determines the direction of the
audio output.
[0045] Another attribute can be the desired distance to be traveled
by the beam. This can be known as a distance input. In one
embodiment, the ultrasonic frequency of the audio output can be
adjusted. By controlling the ultrasonic frequency, the desired
distance traveled by the beam can be adjusted. This will be further
explained below. Thus, with the appropriate control signals, the
directional speaker 226 generates the desired audio output
accordingly.
[0046] FIG. 3A is a diagram illustrating a representative
arrangement 300 suitable for use with the invention. The
representative arrangement 300 uses a directional audio apparatus
302 to deliver audio output, which can be an ultrasonic cone 304
(or beam) of ultrasonic output towards a first user (user-1). The
directional audio apparatus 302 can, for example, be the
directional audio apparatus 100, using any implementation of a
directional audio delivery device. Note that in the representative
arrangement 300, a second user (user-2) and a third user (user-3)
are also in the vicinity of the directional audio apparatus 302.
However, in this example, it is assumed that only the first user
(and not the second and third users) is desirous of hearing the
audio sound. As a result, the directional audio apparatus 302
produces the ultrasonic output in a directionally constrained
manner such that its cone 304 (or beam) is directed towards the
first user (user-1). After the ultrasonic output is mixed or
demodulated in air, the resultant audio sound is delivered to the
first user (user-1). Any resultant audio sound received by the
second user (user-2) and the third user (user-3) is at a
significantly lower level (e.g., not heard). Consequently, the
second user (user-2) and the third user (user-3) are not disturbed
by the audio output that is being heard by the first user
(user-1).
[0047] Another way to control the audio output level to be received
by other users is through the distance input. By controlling the
distance the ultrasonic output travels, the directional audio
delivery device 302 can minimize the audio output that might reach
other persons (i) positioned behind the first user (user-1) not
shown in the figure, or (ii) positioned at a location that would
receive the audio output upon its reflection from surfaces behind
the first user (user-1).
[0048] FIG. 3B is a diagram of a representative building layout 320
illustrating one application of the present invention. The
representative building layout 320 is used to illustrate how a
directional audio apparatus 328 according to the invention can be
utilized. The representative building layout 320 includes a first
room 322, a second room 324 and a third room 326. The first room
322 can, for example, be a family room. The first room 322 includes
a directional audio apparatus 328. A first user (u-1), a second
user (u-2) and a third user (u-3) are in the first room 322. The
directional audio apparatus 328 can deliver audio sound in a
directionally confined manner. The directional audio apparatus 328
can, for example, be the directional audio apparatus 100, using any
implementation of a directional audio delivery device in the
present invention.
[0049] As shown in FIG. 3B, the directional audio apparatus 328
delivers a constrained cone 330 (beam) of audio output or sound
towards the first user (u-1). Note that the audio output is
substantially constrained within the cone 330. As a result, the
second user (u-2) and the third user (u-3) do not hear the audio
output produced by the directional audio apparatus 328 in any
significant way. Some of the sound from the cone 330 might be
reflected or dispersed off a rear wall, and received by the second
and third users. If so, the sound would have attenuated to a
substantially lower level. In one embodiment, the distance covered
by the cone 330 of sound can be adjusted. In another embodiment,
the breath of the cone 330 can be adjusted.
[0050] FIG. 4 is a flow diagram of directional audio delivery
processing 400 according to an embodiment of the invention. The
directional audio delivery processing 400 is, for example,
performed by a directional audio delivery device, such as the
directional audio delivery device 104 illustrated in FIG. 1. More
particularly, the directional audio delivery processing 400 is
particularly suitable for use by the directional audio delivery
device 220 illustrated in FIG. 2B.
[0051] The directional audio delivery processing 400 initially
receives 402 audio signals for directional delivery. The audio
signals can be supplied by an audio system. In addition, a beam
attribute input is received 404. As previously noted, the beam
attribute input is a reference or indication of one or more
attributes regarding the audio output to be delivered. After the
beam attribute input has been received 404, one or more attributes
of the beam are determined 406 based on the attribute input. If the
attribute pertains to the direction of the beam, the input can set
the constrained delivery direction of the beam. The constrained
delivery direction is the direction that the output is delivered.
The audio signals that were received are converted 408 to
ultrasonic signals with appropriate attributes, which may include
one or more of the determined attributes. Finally, the directional
speaker is driven 410 to generate ultrasonic output again with
appropriate attributes. In the case where the direction of the beam
is set, the ultrasonic output is directed in the constrained
delivery direction. Following the operation 410, the directional
audio delivery processing 400 is complete and ends. Note that the
constrained delivery direction can be altered dynamically or
periodically, if so desired.
[0052] FIG. 5 shows examples of beam attributes 500 of the
constrained audio output according to the invention. These beam
attributes 500 can be provided either automatically, such as
periodically, or manually, such as at the request of a user. The
attributes can be for the beam-attribute control unit 224. One
attribute, which has been previously described, is the direction
502 of the beam. Another attribute can be the beam width 504. In
other words, the width of the ultrasonic output can be controlled.
In one embodiment, the beam width is the width of the beam at the
desired position. For example, if the desired location is 10 feet
directly in front of the directional audio apparatus, the beam
width can be the width of the beam at that location. In another
embodiment, the width 504 of the beam is defined as the width of
the beam at its full-width-half-max (FWHM) position.
[0053] The desired distance 506 to be covered by the beam can be
set. In one embodiment, the rate of attenuation of the ultrasonic
output/audio output can be controlled to set the desired distance.
In another embodiment, the volume or amplification of the beam can
be changed to control the distance to be covered. Through
controlling the desired distance, other persons in the vicinity of
the person to be receiving the audio signals (but not adjacent
thereto) would hear little or no sound. If sound were heard by such
other persons, its sound level would have been substantially
attenuated (e.g., any sound heard would be faint and likely not
discernable).
[0054] There are also other types of beam attribute inputs. For
example, the inputs can be the position 508, and the size 510 of
the beam. The position input can pertain to the position of a
person desirous of hearing the audio sound, or the position of an
electronic device (e.g., remote controller). Hence, the
beam-attribute control unit 224 receives the beam position input
and the beam size input, and then determines how to drive the
directional speaker to output the audio sound to a specific
position with the appropriate beam width. Then, the beam-attribute
control unit 226 produces drive signals, such as ultrasonic signals
and other control signals. The drive signals controls the
directional speaker 506 to generate the ultrasonic output towards a
certain position with a particular beam size.
[0055] There can be more than one beam. Hence, one attribute of the
beam is the number 512 of beams present. Multiple beams can be
utilized, such that multiple persons are able to receive the audio
signals via the ultrasonic output by the directional speaker (or a
plurality of directional speakers). Each beam can have its own
attributes.
[0056] There can also be a dual mode operation 514 having a
directional mode and a normal mode. The directional audio apparatus
can include a normal speaker (e.g., substantially omni-directional
speaker). There are situations where a user would prefer the audio
output to be heard by every one in a room, for example. Under this
situation, the user can deactivate the directional delivery
mechanism of the apparatus, or can allow the directional audio
apparatus to channel the audio signals to the normal speaker to
generate the audio output. In one embodiment, a normal speaker
generates its audio output based on audio signals, without the need
for generating ultrasonic outputs. However, a directional speaker
requires ultrasonic signals to generate its audio output.
[0057] FIG. 6 is another representative building layout 600
illustrating an application of the present invention. The
representative building layout 600 is generally similar to the
representative building layout 320 illustrated in FIG. 3B. In this
example, the representative building layout 600 includes a first
room 602, a second room 604 and a third room 606. Although a first
user (u-1), a second user (u-2) and a third user (u-3) are all
within the first room 602, only the first user (u-1) and the second
user (u-2) want to hear the audio sound from an audio system.
Accordingly, the first room 602 includes a directional audio
apparatus 608 to output a cone 610 (or beam) of ultrasonic output
towards the first user (u-1) and the second user (u-2). Note that
the cone 610 can have a greater width or footprint than does the
cone 330 illustrated in FIG. 3B so that it substantially
encompasses both the first user (u-1) and the second user (u-2).
Nevertheless, the third user (u-3) is not proximate to the cone
610; hence, the third user (u-3) is not significantly disturbed by
the audio sound that the first and second users hear by way of the
ultrasonic output from the directional audio apparatus 608.
[0058] Note that the cone 610 or the beam does not have to
propagate directly to the first (u-1) and the second user (u-2). In
one embodiment, the beam can propagate towards the ceiling of the
building, which reflects the beam back towards the floor to be
received by the users. One advantage of such an embodiment is to
lengthen the propagation distance to broaden the width of the beam
when it reaches the users. Another feature of this embodiment is
that the users do not have to be in the line-of-sight of the
directional audio apparatus.
[0059] FIG. 7 is a flow diagram of directional audio delivery
processing 700 according to another embodiment of the invention.
The directional audio delivery processing 700 is, for example,
performed by the directional audio delivery device 104 illustrated
in FIG. 1. More particularly, the directional audio delivery
processing 700 is particularly suitable for use by the directional
audio delivery device 220 illustrated in FIG. 2B.
[0060] The directional audio delivery processing 700 receives 702
audio signals for directional delivery. The audio signals are
provided by an audio system. In addition, two beam attribute inputs
are received, and they are a position input 704 and a beam size
input 706. Next, the directional audio delivery processing 700
determines 708 a delivery direction and a beam size based on the
position input and the beam size input. The desired distance to be
covered by the beam can also be determined. The audio signals are
then converted 710 to ultrasonic signals, with the appropriate
attributes. For example, the frequency and/or the power level of
the ultrasonic signals can be generated to set the desired travel
distance of the beam. Thereafter, a directional speaker (e.g.,
ultrasonic speaker) is driven 712 to generate ultrasonic output in
accordance with, for example, the delivery direction and the beam
size. In other words, when driven 712, the directional speaker
produces ultrasonic output (that carries the audio sound) towards a
certain position, with a certain beam size at that position. In one
embodiment, the ultrasonic signals are dependent on the audio
signals, and the delivery direction and the beam size are used to
control the directional speaker. In another embodiment, the
ultrasonic signals can be dependent on not only the audio signals
but also the delivery direction and the beam size. Following the
operation 712, the directional audio delivery processing 700 is
complete and ends.
[0061] FIG. 8A is a flow diagram of directional audio delivery
processing 800 according to yet another embodiment of the
invention. The directional audio delivery processing 800 is, for
example, suitable for use by the directional audio delivery device
104 illustrated in FIG. 1. More particularly, the directional audio
delivery processing 800 is particularly suitable for use by the
directional audio delivery device 220 illustrated in FIG. 2B, with
the beam attribute inputs being beam position and beam size
received from a remote device.
[0062] The directional audio delivery processing 800 initially
activates a directional audio apparatus that is capable of
constrained directional delivery of audio sound. A decision 804
determines whether a beam attribute input has been received. Here,
in accordance with one embodiment, the audio apparatus has
associated with it a remote control device, and the remote control
device can provide the beam attributes. Typically, the remote
control device enables a user positioned remotely (e.g., but in
line-of-sight) to change settings or characteristics of the audio
apparatus. One beam attribute is the desired location of the beam.
Another attribute is the beam size. According to the invention, a
user of the audio apparatus might hold the remote control device
and signal to the directional audio apparatus a position reference.
This can be done by the user, for example, through selecting a
button on the remote control device. This button can be the same
button for setting the beam size because in transmitting beam size
information, location signals can be relayed as well. The beam size
can be signaled in a variety of ways, such as via a button, dial or
key press, using the remote control device. When the decision 804
determines that no attributes have been received from the remote
control device, the decision 804 can just wait for an input.
[0063] When the decision 804 determines that a beam attribute input
has been received from the remote control device, control signals
for the directional speaker are determined 806 based on the
attribute received. If the attribute is a reference position, a
delivery direction can be determined based on the position
reference. If the attribute is for a beam size adjustment, control
signals for setting a specific beam size are determined. Then,
based on the control signals determined, the desired ultrasonic
output that is constrained is produced 812.
[0064] Next, a decision 814 determines whether there are additional
attribute inputs. For example, an additional attribute input can be
provided to incrementally increase or decrease the beam size. The
user can adjust the beam size, hear the effect and then further
adjust it, in an iterative manner. When the decision 814 determines
that there are additional attribute inputs, appropriate control
signals are determined 806 to adjust the ultrasonic output
accordingly. When the decision 814 determines that there are no
additional inputs, the directional audio apparatus can be
deactivated. When the decision 816 determines that the audio system
is not to be deactivated, then the directional audio delivery
processing 800 returns to continuously output the constrained audio
output. On the other hand, when the decision 816 determines that
the directional audio apparatus is to be deactivated, then the
directional audio delivery processing 800 is complete and ends.
[0065] Besides directionally constraining audio sound that is to be
delivered to a user, the audio sound can optionally be additionally
altered or modified in view of the user's hearing characteristics
or preferences, or in view of the audio conditions in the vicinity
of the user.
[0066] FIG. 8B is a flow diagram of an environmental accommodation
process 840 according to one embodiment of the invention. The
environmental accommodation process 840 determines 842
environmental characteristics. In one implementation, the
environmental characteristics can pertain to measured sound (e.g.,
noise) levels at the vicinity of the user. The sound levels can be
measured by a pickup device (e.g., microphone) at the vicinity of
the user. The pickup device can be at the remote device held by the
user. In another implementation, the environmental characteristics
can pertain to estimated sound (e.g., noise) levels at the vicinity
of the user. The sound levels at the vicinity of the user can be
estimated based on a position of the user/device and/or the
estimated sound level for the particular environment. For example,
sound level in a department store is higher than the sound level in
the wilderness. The position of the user can, for example, be
determined by Global Positioning System (GPS) or other
triangulation techniques, such as based on infrared,
radio-frequency or ultrasound frequencies with at least three
non-collinear receiving points. There can be a database with
information regarding typical sound levels at different locations.
The database can be accessed to retrieve the estimated sound level
based on the specific location.
[0067] After the environmental accommodation process 840 determines
842 the environmental characteristics, the audio signals are
modified based on the environmental characteristics. For example,
if the user were in an area with a lot of noise (e.g., ambient
noise), such as at a confined space with various persons or where
construction noise is present, the audio signals could be processed
to attempt to suppress the unwanted noise, and/or the audio signals
(e.g., in a desired frequency range) could be amplified. One
approach to suppress the unwanted noise is to introduce audio
outputs that are opposite in phase to the unwanted noise so as to
cancel the noise. In the case of amplification, if noise levels are
excessive, the audio output might not be amplified to cover the
noise because the user might not be able to safely hear the desired
audio output. In other words, there can be a limit to the amount of
amplification and there can be negative amplification on the audio
output (even complete blockage) when excessive noise levels are
present. Noise suppression and amplification can be achieved
through conventional digital signal processing, amplification
and/or filtering techniques. The environmental accommodation
process 840 can, for example, be performed periodically or if there
is a break in audio signals for more than a preset amount of time.
The break may signify that there is a new audio stream.
[0068] A user might have a hearing profile that contains the user's
hearing characteristics. The audio sound provided to the user can
optionally be customized or personalized to the user by altering or
modifying the audio signals in view of the user's hearing
characteristics. By customizing or personalizing the audio signals
to the user, the audio output can be enhanced for the benefit or
enjoyment of the user.
[0069] FIG. 8C is a flow diagram of an audio personalization
process 860 according to one embodiment of the invention. The audio
personalization process 860 retrieves 862 an audio profile
associated with the user. The hearing profile contains information
that specifies the user's hearing characteristics. For example, the
hearing characteristics may have been acquired by the user taking a
hearing test. Then, the audio signals are modified 864 or
pre-processed based on the audio profile associated with the
user.
[0070] The hearing profile can be supplied to a directional audio
delivery device performing the personalization process 860 in a
variety of different ways. For example, the audio profile can be
electronically provided to the directional audio delivery device
through a network. As another example, the audio profile can be
provided to the directional audio delivery device by way of a
removable data storage device (e.g., memory card). Additional
details on audio profiles and personalization to enhance hearing
can be found in U.S. patent application Ser. No. ______, filed
______ and entitled "DIRECTIONAL HEARING ENHANCEMENT SYSTEMS",
which is hereby incorporated herein by reference.
[0071] The environmental accommodation process 840 and/or the audio
personalization process 860 can optionally be performed together
with any of the directional audio delivery devices or processes
discussed above. For example, the environmental accommodation
process 840 and/or the audio personalization process 860 can
optionally be performed together with any of the directional audio
delivery processes 400, 700 or 800 embodiments discussed above with
respect to FIGS. 4, 7 and 8. The environmental accommodation
process 840 and/or the audio personalization process 860 typically
would precede the operation 408 in FIG. 4, the operation 710 in
FIG. 7 and/or the operation 812 in FIG. 8A.
[0072] FIG. 9A is a perspective diagram of an ultrasonic transducer
900 according to one embodiment of the invention. The ultrasonic
transducer 900 can implement the directional speakers discussed
herein. The ultrasonic transducer 900 produces the ultrasonic
output utilized as noted above. In one embodiment, the ultrasonic
transducer 900 includes a plurality of resonating tubes 902 covered
by a piezoelectric thin-film, such as PVDF, that is under tension.
When the film is driven by a voltage at specific frequencies, the
structure will resonate to produce the ultrasonic output.
Additional details on the ultrasonic transducer 900 can be found in
U.S. patent application Ser. No. ______, filed ______ and entitled
"DIRECTIONAL WIRELESS COMMUNICATION SYSTEMS", which is hereby
incorporated herein by reference.
[0073] Mathematically, the resonance frequency f of each eigen
mode
[0074] (n,s) of a circular membrane can be represented by:
[0075] f(n,s)=a(n,s)/(2.pi.a)*{square root}(S/m)
[0076] where
[0077] a is the radius of the circular membrane,
[0078] S is the uniform tension per unit length of boundary,
and
[0079] M is the mass of the membrane per unit area.
[0080] For different eigen modes of the tube structure shown in
FIG. 9A,
[0081] a(0,0)=2.4
[0082] a(0,1)=5.52
[0083] a(0,2)=8.65
[0084] . . .
[0085] Assume a(0,0) to be the fundamental resonance frequency, and
is set to be at 50 kHz. Then, a(0,1) is 115 kHz, and a(0,2) is 180
kHz etc. The n=0 modes are all axisymmetric modes. In one
embodiment, by driving the thin-film at the appropriate frequency,
such as at any of the axisymmetric mode frequencies, the structure
resonates, generating ultrasonic waves at that frequency.
[0086] Instead of using a membrane over the resonating tubes, in
another embodiment, the ultrasonic transducer is made of a number
of speaker elements, such as unimorph, bimorph or other types of
multilayer piezoelectric emitting elements. The elements can be
mounted on a solid surface to form an array. These emitters can
operate at a wide continuous range of frequencies, such as from 40
to 200 kHz.
[0087] One embodiment to control the distance of propagation of the
ultrasonic output is by changing the carrier frequency, such as
from 40 to 200 kHz. Frequencies in the range of 200 kHz have much
higher acoustic attenuation in air than frequencies around 40 kHz.
Thus, the ultrasonic output can be attenuated at a much faster rate
at higher frequencies, reducing the potential risk of ultrasonic
hazard to health, if any. Note that the degree of attenuation can
be changed continuously, such as based on multi-layer piezoelectric
thin-film devices by continuously changing the carrier frequency.
In another embodiment, the degree of isolation can be changed more
discreetly, such as going from one eigen mode to another eigen mode
of the tube resonators with piezoelectric membranes.
[0088] FIG. 9B is a diagram that illustrates the ultrasonic
transducer 900 generating its beam 904 of ultrasonic output.
[0089] The width of the beam 904 can be varied in a variety of
different ways. For example, a reduced area or one segment of the
transducer 900 can be used to decrease the width of the beam 904.
In the case of a membrane over resonating tubes, there can be two
concentric membranes, an inner one 910 and an outer one 912, as
shown in FIG. 9C. One can turn on the inner one only, or both at
the same time with the same frequency, to control the beam width.
FIG. 9D illustrates another embodiment 914, with the transducer
segmented into four quadrants. The membrane for each quadrant can
be individually controlled. They can be turned on individually, or
in any combination to control the width of the beam. In the case of
directional speakers using an array of bimorph elements, reduction
of the number of elements can be used to reduce the size of the
beam width. Another approach is to activate elements within
specific segments to control the beam width.
[0090] In yet another embodiment, the width of the beam can be
broadened by increasing the frequency of the ultrasonic output. To
illustrate this embodiment, the dimensions of the directional
speaker are made to be much larger than the ultrasonic wavelengths.
As a result, beam divergence based on aperture diffraction is
relatively small. One reason for the increase in beam width in this
embodiment is due to the increase in attenuation as a function of
the ultrasonic frequency. Examples are shown in FIGS. 9E-9G, with
the ultrasonic frequencies being 40 kHz, 100 kHz and 200 kHz,
respectively. These figures illustrate the audio output beam
patterns computed by integrating the non-linear KZK equation based
on an audio frequency at 1 kHz. The emitting surface of the
directional speaker is assumed to be a planar surface of 20 cm by
10 cm. Such equations are described, for example, in "Quasi-plane
waves in the nonlinear acoustics of confined beams," by E. A.
Zabolotskaya and R. V. Khokhov, which appeared in Sov. Phys.
Acoust., Vol.15, pp.35-40, 1969; and "Equations of nonlinear
acoustics," by V. P. Kuznetsov, which appeared in Sov. Phys.
Acoust., Vol.16, pp.467-470, 1971.
[0091] In the examples shown in FIGS. 9E-9G, the acoustic
attenuations are assumed to be 0.2 per meter for 40 kHz, 0.5 per
meter for 100 kHz and 1.0 per meter for 200 kHz. The beam patterns
are calculated at a distance of 4 m away from the emitting surface
and normal to the axis of propagation. The x-axis of the figures
indicates the distance of the test point from the axis (from -2 m
to 2 m), while the y-axis of the figures indicates the calculated
acoustic pressure in dB SPL of the audio output at the test point.
The emitted power for the three examples are normalized so that the
received power for the three audio outputs on-axis are roughly the
same (e.g. at 56 dB SPL 4 m away). Comparing the figures, one can
see that the lowest carrier frequency (40 kHz in FIG. 9E) gives the
narrowest beam and the highest carrier frequency (200 kHz in FIG.
9G) gives the widest beam. One explanation can be that higher
acoustic attenuation reduces the length of the virtual array of
speaker elements, which tends to broaden the beam pattern. Anyway,
in this embodiment, a lower carrier frequency provides better beam
isolation, with privacy enhanced.
[0092] As explained, the audio output is in a constrained beam for
enhanced privacy. Sometimes, although a user would not want to
disturb other people in the immediate neighborhood, the user may
want the beam to be wider or more divergent. A couple may be
sitting together to watch a movie. Their enjoyment would be reduced
if one of them cannot hear the movie because the beam is too
narrow. In a number of embodiments to be described below, the width
of the beam can be expanded in a controlled manner based on curved
structural surfaces or other phase-modifying beam forming
techniques.
[0093] FIG. 10A illustrates one approach to diverge the beam based
on an ultrasonic speaker with a convex emitting surface. The
surface can be structurally curved in a convex manner to produce a
diverging beam. The embodiment shown in FIG. 10A has a
spherical-shaped ultrasonic speaker 1000, or an ultrasonic speaker
whose emitting surface of ultrasonic output is spherical in shape.
In the spherical arrangement 1000, a spherical surface 1002 has a
plurality of ultrasonic elements 1004 affixed (e.g. bimorphs) or
integral thereto. The ultrasonic speaker with a spherical surface
1002 forms a spherical emitter that outputs an ultrasonic output
within a cone (or beam) 1006. Although the cone will normally
diverge due to the curvature of the spherical surface 1002, the
cone 1006 remains directionally constrained.
[0094] In an embodiment where speaker elements are affixed or
coupled to a spherical surface, each ultrasonic element 1004 is
oriented to point towards the center of a sphere of which the
spherical surface 1002 is a part of. In one embodiment where
elements are integral to a spherical or curved surface, there can
be a plurality of resonating tubes 1026, as shown in FIG. 10B. The
length-wise axis of each resonating cavity 1026 points to the
center of the sphere of which the spherical surface 1002 is a part
of. The resonating tubes 1026 can be formed in a single fabrication
step so as to ensure their uniformity. This can be done, for
example, by form-pressing all of the holes at the same time.
[0095] In the embodiment where the ultrasonic speaker includes
resonating tubes, there is a thin-film piezoelectric membrane
mounted on one side of the tubes. It can be either on the convex
side 1034 or the concave side 1036 of a surface 1010, as shown in
FIG. 10B. In the embodiment of the surface 1010 shown in FIG. 10B,
the membrane is assumed to be mounted on the concave side 1036.
After the membrane is mounted, a vacuum can be formed to have the
membrane press onto the tubes. Voltages can be applied to the
membrane to generate the ultrasonic output. This creates an
emitting surface that is structurally curved in a concave manner.
As shown in FIG. 10B, the beam produced 1040 initially converges
and then diverges.
[0096] The degree of divergence is determined, for example, by the
curvature of the surface 1002 or 1036. In one embodiment, referring
back to FIG. 10A, the radius of the spherical surface is about 40
cm, its height 1007 is about 10 cm and its width 1008 is about 20
cm.
[0097] Diverging beams can also be generated even if the emitting
surface of the ultrasonic speaker is a planar surface. For example,
as shown in FIG. 10C, a convex reflector 1050 can be used to
reflect the beam 904 into a diverging beam 918 (and thus with an
increased beam width). In this embodiment, the ultrasonic speaker
can be defined to include the convex reflector 1050.
[0098] Another way to modify the shape of a beam, so as to diverge
or converge the beam, is through controlling phases. In one
embodiment, the directional speaker includes a number of speaker
elements, such as bimorphs. The phase shifts to individual elements
of the speaker can be individually controlled. With the appropriate
phase shift, one can generate ultrasonic outputs with a quadratic
phase wave-front to produce a converging or diverging beam. For
example, the phase of each emitting element is modified by
k*r.sup.2/(2F.sub.0), where (a) r is the radial distance of the
emitting element from the point where the diverging beam seems to
originate from, (b) F.sub.0 is the desired focal distance, (c)
k--the propagation constant of the audio frequency f--is equal to
2.pi.f/c.sub.0, where c.sub.0 is the acoustic velocity.
[0099] In yet another example, beam width can be changed by
modifying the focal length or the focus of the beam, or by
de-focusing the beam. This can be done electronically through
adjusting the relative phases of the ultrasonic signals exciting
different directional speaker elements.
[0100] Curved surfaces can also be segmented to control the beam
width or beam propagating direction. FIG. 11A illustrates a
cylindrical-shaped ultrasonic speaker 1100 according to an
embodiment of the invention. In this embodiment, the emitting
surface of the directional speaker is cylindrical in shape and is
segmented. In the cylindrical arrangement 1100, a cylindrical
surface 1102 has a plurality of ultrasonic elements 1104 affixed
(e.g., bimorphs) or integral thereto (e.g., tubes covered by a
membrane). Each ultrasonic element 1104 is oriented horizontally
on, but pointed towards the center line of, a cylinder of which the
cylindrical surface 1102 is a part of. In the case of elements
being resonating tubes, the length-wise axis of each tube is
horizontal and points towards the center line of the cylinder of
which the cylindrical surface 1102 is a part of. Again, although
the cone of ultrasonic output 1106 will normally diverge, the cone
remains directionally constrained. In one embodiment, the radius of
the cylindrical surface 1102 of the cylinder-shaped ultrasonic
speaker 1100 is about 40 cm, its height 1110 is about 10 cm and its
width 1112 is about 20 cm.
[0101] In the speaker embodiment shown in FIG. 11A, the cylindrical
surface 1102 can be segmented, such as into three separate
controllable segments 1105, 1107 and 1109. Each of the segments can
be selectably activated to control the direction and/or width of
the ultrasonic output. For the embodiment where the speaker is made
of tubes covered by membranes, each segment can have its own
membrane. To generate the widest beam, all three segments are
activated simultaneously by signals with substantially the same
frequencies, phases and amplitudes.
[0102] FIG. 11B shows another example of segmenting the emitting
surface according to the present invention. A transducer surface
1140 has a curved configuration 1142 that includes four
controllable segments 1144, 1146, 1148 and 1150. Each of the
segments of the curved configuration 1142 can be selectably
activated to control the direction and/or width of the ultrasonic
output. For example, the ultrasonic output from the segment 1144
resides within the constrained region 1152. The ultrasonic output
by the segment 1146 resides within the constrained area 1154. The
ultrasonic output by the segment 1148 resides within the
constrained area 1156. The ultrasonic output from the segment 1150
resides within the constrained area 1158. By selectively
controlling the selectable segments of the curved configuration
1142, the width of the ultrasonic output (and thus the resulting
audio output) can be controlled.
[0103] Segmenting the transducer surface shown in FIG. 11B can be
done by turning on elements in the different segments. To
illustrate, referring to FIG. 10A, a subset of the ultrasonic
elements 1004 can be activated. For example, the spherical emitter
is shown as having sixty-four (64) ultrasonic elements 1004, which
can be bimorph devices. A smaller beam could be emitted if, for
example, only the interior sixteen (16) ultrasonic elements were
utilized.
[0104] Still further, the propagation direction of the ultrasonic
beam, such as the beam 1006 in FIG. 10A, the beam 1040 in FIG. 10B
or the beam 1106 in FIG. 11A, can be changed by electrical and/or
mechanical mechanisms. To illustrate based on the spherical-shaped
ultrasonic speaker shown in FIG. 1A, a user can physically
reposition the spherical surface 1002 to change its beam's
orientation or direction. Alternatively, a motor can be
mechanically coupled to the spherical surface 1002 to change its
orientation or the propagation direction of the ultrasonic output.
In yet another embodiment, the direction of the beam can be changed
electronically based on phase array techniques.
[0105] The movement of the spherical surface 1002 to adjust the
delivery direction can track user movement. This tracking can be
performed dynamically. This can be done through different
mechanisms, such as by GPS or other triangulation techniques. The
user's position is fed back to or calculated by the directional
audio apparatus. The position can then become a beam attribute
input. The beam-attribute control unit would convert the input into
the appropriate control signals to adjust the delivery direction of
the audio output. The movement of the spherical surface 1002 can
also be in response to a user input. In other words, the movement
or positioning of the beam 1006 can be done automatically or at the
instruction of the user.
[0106] FIGS. 12A and 12B are perspective diagrams of one embodiment
of directional audio apparatus that provides directional audio
output to interested users. FIG. 12A illustrates a directional
audio apparatus 1200 that includes an entertainment center, such as
a television 1202, a set-top box 1204 and a directional speaker
1206. The television 1202 displays video that is supplied, for
example, by a satellite link or a cable line via the set-top box
1204. Typically, the set-top box 1204 operates to decode the
encoded video and audio content transmitted over the satellite link
or cable line. Once decoded, the appropriate audio and video
signals are delivered to the television 1202. The television 1202
may include conventional or normal speakers to provide audio
output. These speakers typically do not produce audio output
through generating ultrasonic signals to be converted into the
audio frequency range by interaction with air. Nevertheless, the
audio apparatus 1200 includes the directional speaker 1206. The
directional speaker 1206 provides delivery of audio signals in a
constrained direction. Further, the directionally-constrained audio
outputs can be controlled as to the target distance for its users
as well as for the width of the resulting audio beam. The
directional speaker 1206 generates ultrasonic output by way of an
emitter surface 1208. The emitter surface 1208 can include a single
or multiple segments of groups of ultrasonic or speaker
elements.
[0107] Furthermore, the directional speaker 1206 is mounted to the
set-top box 1204 such that its position can be adjusted with
respect to the set-top box 1204 as well as the television 1202. For
example, the directional speaker 1206 can be rotated to cause a
change in the direction in which the directionally-constrained
audio output outputs are delivered. In one embodiment, a user of
the audio system 1200 can manually position (e.g., rotate) the
directional speaker 1206 to adjust the delivery direction. In
another embodiment, the directional speaker 1206 can be positioned
(e.g., rotated) by way of an electrical motor provided within the
set-top box 1204 or the directional speaker 1206. Such an
electrical motor can be controlled by a conventional control
circuit and can be instructed by one or more buttons provided on
the set-top box 1204, the directional speaker 1206 or a remote
control device.
[0108] FIG. 12B is a diagram of another directional audio apparatus
1220 in a set-top box environment according to another embodiment
of the invention. The audio apparatus 1220 includes an
entertainment system, such as a television 1222, a set-top box 1224
and a directional speaker 1226. The set-top box 1224 is typically
coupled to a satellite link or a cable line to receive audio and
video signals. The set-top box 1224 decodes the audio and video
signals and supplies the resulting audio and video signals to the
television 1222. The television 1222 displays the video signals and
may use its conventional speakers to output audio sound. However,
when directional delivery of audio sound is desired, the
conventional speakers of the television 1222 are not utilized.
Instead, the directional speaker 1226 is utilized. The directional
speaker 1226, for example, can be activated by a button, switch or
other means. Once activated, the directional speaker 1226 outputs
the audio signals in a directionally constrained manner. In one
approach, the television 1222 has an audio-output connection that
is connected to the set-top box 1224. If conventional speakers are
preferred, the signal line from the audio-output connection is
electrically disconnected, and normal audio output is directly from
the television 1222. However, in one embodiment, if
directionally-constrained audio output is desired, audio signals
from the television 1222 are channeled to the set-top box 1224, and
normal audio output from the television 1222 is de-activated. In
yet another embodiment, the volume control in the television 1222
can be turned down if directionally-constrained audio outputs are
preferred.
[0109] Still further, the set-top box 1224 and/or the directional
speaker 1226 can permit control over the distance and/or width of
the audio output to be transmitted to the one or more interested
users. In this embodiment, the position of the directional speaker
1226 is fixed relative to the set-top box 1224. In one embodiment,
the directional speaker 1226 is affixed to the set-top box 1224. In
another embodiment, the directional speaker 1226 is integral with
the set-top box 1224. In any case, the direction for the
directionally-constrained audio output outputs can be electrically
controlled through a variety of different techniques. One technique
is to activate only certain segments of the emitting surface 1228
of the directional speaker 1226. Another technique is to utilize
beam-steering operations based on phase control inputs.
[0110] The directional audio apparatuses 1200 and 1220 illustrated
in FIGS. 12A and 12B can utilize the various methods and processes
discussed above. The set-top boxes with directional speakers shown
in FIGS. 12A and 12B are able to transform conventional audio
systems in televisions into audio systems having directional audio
delivery as explained in the present invention.
[0111] To illustrate, the directional speaker with the emitting
surface 1140 shown in FIG. 11B can be used as the emitting surface
1228 for the directional speaker 1226 illustrated in FIG. 12B. For
example, initially only the segment 1146 is in operation. The user
signals the set-top box that its beam width should be increased.
Then the segment 1148 can be additionally activated, thereby
increasing the width or area associated with the ultrasonic output
(and thus resulting audio outputs). In yet another application,
non-adjacent segments can be simultaneously activated to generate
multiple separate beams. For example, a user can signal the set-top
box to activate the two outer most beams, 1152 and 1158. This will
generate two separate beams for two separate users. Then, a person
located in the middle between the two users would only hear a
substantially reduced output level.
[0112] In another example, more than one user are sitting close to
the television 1200 in FIG. 12A. It would be advantageous to have a
wider beam that covers a shorter distance. One embodiment uses a
directional speaker 1206 that operates at a higher frequency, such
as the one shown in FIG. 9G, working at 200 kHz. The beam width is
broader than the version shown in FIG. 9E, but the beam covers a
shorter distance due to higher attenuation.
[0113] FIG. 13 is a perspective diagram of a remote control device
1300 according to one embodiment of the invention. The remote
control device 1300 is one embodiment for a directional audio
apparatus. The remote control device 1300 has a top surface 1302
with a plurality of buttons 1304 as is common with remote
controllers. Some of these buttons 1304 can correspond to various
options a user might request of a directional audio apparatus via a
remote control device. Examples of these options include start,
stop, play, channels, volume, etc. In one embodiment, the remote
control device 1300 also includes options for the beam attribute
inputs, such as discrete sizes of beam width (e.g., large, medium
and small), and discrete distance coverage (e.g., long, medium and
short).
[0114] The remote control device 1300 can also include a
directional speaker 1306 that produces directional audio delivery
to one or at most a few users desirous of hearing the audio output.
The directional speaker 1306 can be substantially flush or recessed
with respect to the top surface 1302. In any case, a grating 1308
can optionally be provided over the directional speaker 1306. Still
further, the directional speaker can be mounted at an angle with
respect to the top surface 1302, or can be movably mounted with
respect to the top surface 1302 so that the direction of delivery
can be manipulated. Alternatively, a thin layer of material (e.g.,
plastic housing) can cover the directional speaker 1306 to provide
protection, if required, yet still allow sound to pass through.
Additional details on the directional speaker 1306 can be found in
U.S. patent application No. ______, filed ______ and entitled
"DIRECTIONAL WIRELESS COMMUNICATION SYSTEMS", which is hereby
incorporated herein by reference. A wireless link window 1310
provides a window through which the remote control device 1300 is
able to communicate in a wireless manner (e.g., radio or optical)
with an audio system, which may or may not have directional audio
capability. Audio signals can then be received and directed to one
or at most a few users proximate to the remote control device 1300
via the directional speaker 1306.
[0115] Depending on the power level of the ultrasonic signals,
sometimes, it might be beneficial to reduce its level in free space
to prevent any potential health hazards, if any. FIGS. 14A-14B show
two such embodiments that can be employed, for example, for such a
purpose. FIG. 14A illustrates a directional speaker with a planar
emitting surface 1404 of ultrasonic output. The dimension of the
planar surface can be much bigger than the wavelength of the
ultrasonic signals. For example, the ultrasonic frequency is 100
kHz and the planar surface dimension is 15 cm, which is 50 times
larger than the wavelength. With a much bigger dimension, the
ultrasonic waves emitting from the surface are controlled so that
they do not diverge significantly within the enclosure 1402. In the
example shown in FIG. 14A, the directional audio delivery device
1400 includes an enclosure 1402 with at least two reflecting
surfaces for the ultrasonic waves. The emitting surface 1404
generates the ultrasonic waves, which propagate in a beam 1406. The
beam reflects within the enclosure 1402 back and forth at least
once by reflecting surfaces 1408. After the multiple reflections,
the beam emits from the enclosure at an opening 1410 as the output
audio 1412. The dimensions of the opening 1410 can be similar to
the dimensions of the emitting surface 1404. In one embodiment, the
last reflecting surface can be a concave or convex surface 1414,
instead of a planar reflector, to generate, respectively, a
converging or diverging beam for the output audio 1412. Also, at
the opening 1410, there can be an ultrasonic absorber to further
reduce the power level of the ultrasonic output in free space.
[0116] FIG. 14B shows another embodiment of a directional audio
delivery device 1450 that allows the ultrasonic waves to bounce
back and forth at least once by ultrasonic reflecting surfaces
before emitting into free space. In FIG. 14B, the directional
speaker has a concave emitting surface 1460. As explained by FIG.
10B, the concave surface first focuses the beam and then diverges
the beam. For example, the focal point 1464 of the concave surface
1460 is at the mid-point of the beam path within the enclosure.
Then with the last reflecting surface 1462 being flat, convex or
concave, the beam width at the opening 1466 of the enclosure can be
not much larger than the beam width right at the concaved emitting
surface 1460. However, at the emitting surface 1460, the beam is
converging. While at the opening 1466, the beam is diverging. The
curvatures of the emitting and reflecting surfaces can be computed
according to the desired focal length or beam divergence angle
similar to techniques used in optics, such as in telescopic
structures.
[0117] More than one directional audio delivery device can be
employed to provide stereo effects. FIG. 15 shows one such
embodiment as illustrated by a building layout 1500. An audio
system 1506 is coupled to two directional audio delivery devices
1502 and 1504 that are spaced apart. In one approach, the audio
system transmits different types of audio signals, either wireline
or wirelessly, to the two directional audio delivery devices 1502
and 1504. For example, the different types of audio signals can
represent a left channel and a right channel. The two directional
audio delivery devices 1502 and 1504 generate two
directionally-constrained audio output beams 1510 and 1512 that are
directed towards and received by a user 1508. Note that the number
of directional audio delivery devices does not have to be limited
to two. For example, a surround sound arrangement can be achieved
through more than two directional audio delivery devices.
[0118] The various embodiments, implementations and features of the
invention noted above can be combined in various ways or used
separately. Those skilled in the art will understand from the
description that the invention can be equally applied to or used in
other various different settings with respect to various
combinations, embodiments, implementations or features provided in
the description herein.
[0119] The invention can be implemented in software, hardware or a
combination of hardware and software. A number of embodiments of
the invention can also be embodied as computer readable code on a
computer readable medium. The computer readable medium is any data
storage device that can store data which can thereafter be read by
a computer system. Examples of the computer readable medium include
read-only memory, random-access memory, CD-ROMs, magnetic tape,
optical data storage devices, and carrier waves. The computer
readable medium can also be distributed over network-coupled
computer systems so that the computer readable code is stored and
executed in a distributed fashion.
[0120] The advantages of the invention are numerous. Different
embodiments or implementations may yield different advantages. One
advantage of the invention is that audio output from a directional
audio apparatus can be directionally constrained so as to provide
directional audio delivery. The directionally-constrained audio
output can provide less disturbance to others in the vicinity who
are not desirous of hearing the audio output. A number of
attributes of the constrained audio outputs can be adjusted, either
by a user or automatically and dynamically based on certain
monitored or tracked measurements, such as the position of the
user.
[0121] One adjustable attribute is the direction of the constrained
audio outputs. It can be controlled, for example, by (a) activating
different segments of a planar or curved speaker surface, (b) using
a motor, (c) manually moving the directional speaker, or (d)
through phase array beam steering techniques.
[0122] Another adjustable attribute is the width of the beam of the
constrained audio outputs. It can be controlled, for example, by
(a) modifying the frequency of the ultrasonic signals, (b)
activating one or more segments of the speaker surface, (c) using
phase array beam forming techniques, (d) employing curved speaker
surfaces to diverge the beam, (e) changing the focal point of the
beam, or (f) de-focusing the beam.
[0123] The degree of isolation or privacy can also be controlled
independent of the beam width. For example, one can have a wider
beam that covers a shorter distance through increasing the
frequency of the ultrasonic signals. Isolation or privacy can also
be controlled through, for example, (a) phase array beam forming
techniques, (b) adjusting the focal point of the beam, or (c)
de-focusing the beam.
[0124] The volume of the audio output can be modified through, for
example, (a) changing the amplitude of the ultrasonic signals
driving the directional speakers, (b) modifying the ultrasonic
frequency to change its distance coverage, or (c) activating more
segments of a planar or curved speaker surface.
[0125] The audio output can also be personalized or adjusted based
on the audio conditions of the areas surrounding the directional
audio apparatus. Signal pre-processing techniques can be applied to
the audio signals for such personalization and adjustment.
[0126] Ultrasonic hazards, if any, can be minimized by increasing
the path lengths of the ultrasonic waves from the directional
speakers before the ultrasonic waves emit into free space. There
can also be an ultrasonic absorber to attenuate the ultrasonic
waves before they emit into free space. Another way to reduce
potential hazard, if any, is to increase the frequency of the
ultrasonic signals to reduce their distance coverage.
[0127] Stereo effects can also be introduced by using more than one
directional audio delivery devices that are spaced apart. This will
generate multiple and different constrained audio outputs to create
stereo effects for a user.
[0128] Directionally-constrained audio output outputs are not
limited to be generated by set-top boxes. They can also be
generated from a remote control.
[0129] Numerous embodiments of the present invention have been
applied to an indoor environment, using building layouts. However,
many embodiments of the present invention are perfectly suitable
for outdoor applications also. For example, a user can be sitting
inside a patio reading a book, while listening to music from a
directional audio apparatus of the present invention. The apparatus
can be outside, such as 10 meters away from the user. Due to the
directionally constrained nature of the audio output, sound can
still be localized within the direct vicinity of the user. As a
result, the degree of noise pollution to the user's neighbors is
significantly reduced.
[0130] Finally, an existing audio system can be modified with one
of the described set-top boxes to generate
directionally-constrained audio output outputs. A user can select
either directionally constrained or normal audio outputs from the
audio system, as desired.
[0131] Numerous specific details are set forth in order to provide
a thorough understanding of the invention. However, it will be
understood by those skilled in the art that the invention may be
practiced without these specific details. The description and
representation herein are the common meanings used by those
experienced or skilled in the art to most effectively convey the
substance of their work to others skilled in the art. In other
instances, well-known methods, procedures, components, and
circuitry have not been described in detail to avoid unnecessarily
obscuring aspects of the present invention.
[0132] In the foregoing description, reference to "one embodiment"
or "an embodiment" means that a particular feature, structure, or
characteristic described in connection with the embodiment can be
included in at least one embodiment of the invention. The
appearances of the phrase "in one embodiment" in various places in
the specification are not necessarily all referring to the same
embodiment, nor are separate or alternative embodiments mutually
exclusive of other embodiments. Further, the order of blocks in
process flowcharts or diagrams representing one or more embodiments
of the invention do not inherently indicate any particular order
nor imply any limitations in the invention.
[0133] The many features and advantages of the present invention
are apparent from the written description and, thus, it is intended
by the appended claims to cover all such features and advantages of
the invention. Further, since numerous modifications and changes
will readily occur to those skilled in the art, it is not desired
to limit the invention to the exact construction and operation as
illustrated and described. Hence, all suitable modifications and
equivalents may be resorted to as falling within the scope of the
invention.
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