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JP2016508012

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JP2016508012
The ultrasonic audio speaker includes an emitter and a driver. The emitter includes a first layer
having a conductive surface, a second layer having a conductive surface, and an insulating layer
disposed between the first layer and the second layer, the first layer and the second The layer
can be placed in contact with the insulating layer. The drive circuit may include two inputs and
two outputs coupled together to receive a voice modulated ultrasound carrier signal from the
amplifier. The first output is coupled to the conductive surface of the first layer, and the second
output is coupled to the conductive surface of the second layer. [Selected figure] Figure 4
Improved parametric transducer and related method
[0001]
The present disclosure relates generally to parametric speakers. More specifically, some
embodiments relate to ultra-thin ultrasound emitters.
[0002]
Non-linear transduction results from introducing an audio modulated ultrasonic signal of
sufficient intensity into the air column. Self-demodulation or down-conversion occurs along the
air column, resulting in the generation of an audible acoustic signal. This process assumes that
when two sound waves of different frequencies are emitted simultaneously in the same medium,
a modulation waveform containing the sum and difference of the two frequencies is generated by
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the non-linear (parametric) interaction of the two sound waves It occurs by well-known physical
principles. If the two original sound waves are ultrasound and their difference is chosen to be at
an audible frequency, an audible sound can be generated by parametric interaction.
[0003]
Parametric speech reproduction systems produce speech by heterodyne of two acoustic signals
in non-linear processing that occurs in a medium, for example air. In general, the acoustic signal
is in the ultrasonic frequency range. Consequently, the non-linearity of the medium gives rise to
an acoustic signal generated by the medium, which is the sum difference of the acoustic signals.
Thus, two ultrasound signals separated by frequency can produce different sounds from 60 Hz to
20,000 Hz that humans can hear.
[0004]
Embodiments of the technology described herein include an ultrasonic audio speaker system,
comprising an emitter and a driver circuit (driver). In many embodiments, the emitter includes a
first layer having a conductive surface, a second layer having a conductive surface, and an
insulating layer deposited between the first conductive surface and the second conductive
surface. , The first layer and the second layer are arranged to be in contact with the insulating
layer. The drive circuit may include two inputs configured to be coupled to receive the voice
modulated ultrasound signal from the amplifier and two outputs. For the two outputs, a first
output is coupled to the conductive surface of the first layer and a second output is coupled to
the conductive surface of the second layer.
[0005]
Either or both conductive layers can be made using a metallized film in which a metallized
conductive layer is deposited on a film substrate. The substrate is, for example, polypropylene,
polyimide, polyethylene terephthalate (PET), axially oriented polyethylene terephthalate, biaxially
oriented polyethylene terephthalate (eg Mylar®, Melinex® or Hostaphan®). Trademark),
Kapton® or other substrates. The insulating layer may be a substrate of a metallized film, or it
may be a separate insulating layer.
04-05-2019
2
[0006]
In many embodiments, the ultrasound emitter further comprises a screen or grating disposed
adjacent to the first conductive layer. In one embodiment, the first conductive layer comprises a
metallized film and the second conductive layer comprises a conductive grating. In another
embodiment, the second conductive layer comprises conductive gratings.
[0007]
Other features of the present invention will become apparent from the following detailed
description, taken in conjunction with the associated drawings. The drawings illustrate features
according to embodiments of the present invention by way of example. The summary of the
invention does not limit the scope of the invention, which is defined solely by the claims
appended hereto.
[0008]
The invention will be described in detail with reference to the associated drawings, in accordance
with one or more various embodiments. The drawings are provided for the purpose of illustration
only and represent only typical or illustrative embodiments of the present invention. These
drawings are provided to facilitate the reader's understanding of the systems and methods
described herein, and should not be considered as limiting the scope, scope, or applicability of
the claimed invention. .
[0009]
Several of the drawings included herein illustrate various embodiments of the invention from
different viewing angles. The relevant text may refer to elements depicted as "top", "bottom" or
"sides" of the device, but such references are merely illustrative and unless explicitly stated
Neither does it imply or require that the present invention be practiced or used in a particular
spatial orientation.
[0010]
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FIG. 1 is a schematic diagram illustrating an ultrasound system suitable for use in the emitter
technology described herein. FIG. 2 is a schematic diagram illustrating another example of a
signal processing system suitable for use in the emitter technology described herein. FIG. 3 is an
exploded schematic diagram illustrating an example emitter in accordance with one embodiment
of the presently described technology. FIG. 4 is a schematic diagram illustrating a cross-sectional
view of the assembled emitter in accordance with the example illustrated in FIG. FIG. 5 is a
schematic diagram illustrating another example configuration of an ultrasound emitter in
accordance with one embodiment of the presently described technology. FIG. 6a is a schematic
diagram illustrating an example of a simple drive circuit that can be used to drive the emitter
disclosed herein. FIG. 6b is a schematic diagram illustrating a cross-sectional view of an example
pot core that may be used to form a pot core inductor. FIG. 7 is a schematic diagram illustrating
another example emitter configuration according to one embodiment of the presently described
technology. FIG. 8 is a schematic diagram illustrating another example emitter configuration
according to one embodiment of the presently described technology. FIG. 9a is a schematic
diagram illustrating an example of an emitter in an arched configuration. FIG. 9b is a schematic
diagram illustrating an example of an emitter in a tubular configuration. FIG. 10a is a schematic
diagram illustrating an example of an emitter in an arched configuration. FIG. 10b is a schematic
diagram illustrating an example of an emitter in a tubular configuration.
[0011]
The drawings are not intended to be exhaustive or to limit the invention to the precise forms
disclosed. It is to be understood that the invention can be practiced with modifications and
variations, and that the invention is limited only by the claims and the equivalents thereof.
[0012]
The embodiments and methods of the present system described herein provide a HyperSonic
Sound (HSS) audio system or other ultrasound audio system for a variety of different
applications. Certain embodiments provide a thin film ultrasound emitter for ultrasound carrier
sound applications.
[0013]
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FIG. 1 is a schematic diagram illustrating an ultrasound system suitable for use with the systems
and methods described herein. In this exemplary ultrasound system 1, audio content from a
sound source 2 is received, such as, for example, a microphone, memory, data storage, streaming
media source, CD, DVD, or other sound source. The sound source is decoded and converted from
digital form to analog form by the sound source. Audio content received from the audio system 1
is modulated onto an ultrasound carrier of frequency f1 using a modulator. The modulator
typically includes a local oscillator (oscillator) 3 for generating an ultrasonic carrier signal and a
multiplier 4 for multiplying the audio signal by the carrier signal. The resulting signal is a double
sideband signal or single sideband signal containing carrier at frequency f1. In one embodiment,
the signal is a parametric ultrasound or HSS signal. In many cases, the modulation scheme used
is amplitude modulation (AM). AM can be realized by multiplying an ultrasound carrier with an
information-carrying signal. The spectrum of the modulated signal has two sidebands, an upper
sideband and a lower sideband, which are symmetrical with respect to the carrier frequency and
the carrier itself.
[0014]
The modulated ultrasound signal is provided to the transducer 6, which injects ultrasound into
the air creating ultrasonic wave 7. When reproducing at a sufficiently high sound pressure level
via the converter, the non-linear effect of the air "regenerated" or transmitted therein mixes the
carriers in the signal with the sidebands, demodulates the signal, and voices Reproduce the
content. This is sometimes called self demodulation. Thus, even in a single sideband
implementation, carriers may be included in the injected signal, whereby self demodulation may
be performed. Although the system illustrated in FIG. 3 uses a single transducer to inject a single
channel of audio content, one skilled in the art after reading this description can use an
ultrasound carrier to It will be appreciated how multiple mixers, amplifiers and converters may
be used to transmit multiple channels of the
[0015]
One example of a signal processing system 10 suitable for use with the techniques described
herein is schematically illustrated in FIG. In this embodiment, the various processing circuits or
components are illustrated in sequence (related to the processing path of the signal), which are
arranged according to one run. It will be appreciated that the components of the processing
circuit are variable, and the order in which the input signals are processed is also variable with
each circuit or component. Further, in some embodiments, processing system 10 may include
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more or less components or circuits than shown herein.
[0016]
Also, the example shown in FIG. 1 processes two input channels and an output channel (eg, a
"stereo" signal), including various components or circuits that include components that
substantially match each channel of the signal. Optimized for use in cases. Those skilled in the art
after reading this description will find that the audio system uses a single channel (eg "monaural"
or "mono" signal), two channels (as illustrated in FIG. 2), or more. It will be understood that it can
be realized by
[0017]
Referring now to FIG. 2, an exemplary signal processing system 10 may include an audio input
that may correspond to the left channel 12a and the right channel 12b of an audio input signal.
Compressor circuits 14a, 14b may be included to compress the dynamic range of the input
signal, effectively amplifying the amplitude of one portion of the input signal, and effectively the
amplitude of the other portion of the input signal. Attenuate. More specifically, compressor
circuits 14a, 14b may be included to narrow the range of audio amplitudes. In one form, the
compressor attenuates the peak-to-peak (pp, peak-to-peak) amplitude of the input signal at a
ratio of at least about 2: 1. Adjustment of the input signal to narrow the range of amplitudes may
be performed to minimize distortion, which is a characteristic of the limited dynamic range in
this class of modulation system.
[0018]
After the speech signal is compressed, equalization networks 16a, 16b may be included for signal
equalization. The equalization network can, for example, raise or suppress a predetermined
frequency or frequency range to enhance the benefits naturally provided by the emitter /
inductor combination of the parametric emitter assembly.
[0019]
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Low pass filter circuits 18a, 18b may be included to provide blocking of the high band (high
frequency domain) of the signal, and the high pass filter circuits 20a, 20 b may block the low
band (low frequency domain) of the audio signal. I will provide a. In an exemplary embodiment,
low pass filter circuits 18a, 18b are used to block signals higher than about 15-20 kHz, and high
pass filters to block signals lower than about 20-200 Hz. Circuits 20a, 20b are used.
[0020]
The high pass filter circuits 20a, 20b may be configured to remove low frequencies that cause
deviation from the carrier frequency after modulation (eg, the portion of the modulated signal of
FIG. 6 that most closely approximates the carrier frequency). Also, some low frequencies are
difficult for the system to reproduce effectively, and as a result, much energy may be wasted
trying to reproduce this frequency. Thus, the high pass filter circuits 20a, 20b can be configured
to block this frequency.
[0021]
The low pass filter circuits 18a, 18b may be configured to remove high frequencies that cause
the carrier to generate an audible beat signal after modulation. For example, if the low pass filter
blocks frequencies above 15 kHz and the carrier frequency is about 44 kHz, then the differential
signal is above about 29 kHz and is outside the human hearing range. However, if a frequency as
low as 25 kHz can pass through the filter circuit, then the generated differential signal can be in
the range of 19 kHz, which is within the human audible range.
[0022]
In the illustrated system 10, after passing through the low pass filter and the high pass filter, the
audio signal is modulated by the modulators 22a, 22b. The modulators 22a and 22b mix or
combine the voice signal and the carrier signal generated by the oscillator 23. For example, in
one embodiment, a single oscillator (in one embodiment, driven at a selected frequency of 40
kHz to 50 kHz, this range corresponds to a readily available crystal that can be used in the
oscillator) is a modulator It is used to drive both 22a, 22b. By using a single oscillator for
multiple modulators, the ideal carrier frequency is provided to the multiple channels output by
the modulators 24a, 24b. Using the same carrier frequency for each channel reduces the risk of
audible beat frequencies.
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[0023]
High pass filter circuits 27a, 27b may also be included after the modulation stage. The high pass
filter circuits 27a, 27b may be used to pass the modulated ultrasound carrier signal, and the high
pass filter circuits 27a, 27b ensure that the audio frequency does not enter the amplifier via the
outputs 24a, 24b. to be certain. That is, in one embodiment, the high pass filter circuits 27a, 27b
may be configured to filter out signals below about 25 kHz.
[0024]
FIG. 3 is an exploded schematic diagram illustrating an example emitter in accordance with one
embodiment of the presently described technology. The emitter illustrated in FIG. 3 includes one
conductive surface 45, another conductive surface 46, an insulating layer 47 and gratings 48. In
the illustrated example, the conductive surface 45 is deposited on the support plate 49. In
various embodiments, the support plate 49 is a nonconductive support plate and serves to
insulate the back side of the conductive surface 45. For example, the conductive surface 45 and
the support plate 49 can be implemented as a metallized layer deposited on a non-conductive or
less conductive substrate.
[0025]
As a further example, the conductive surface 45 and the support plate 49 can be implemented as
a printed circuit board (or similar material) with the metallization layer deposited thereon. As
another example, the conductive surface 45 may be laminated or sputtered to the support plate
49 or may be applied to the support plate 49 using various deposition techniques including, for
example, vapor deposition and thermal spraying. In yet another example, the conductive layer 45
may be a metallized film.
[0026]
The conductive layer 45 may be a continuous surface, or may have slots, holes, cutouts of
various shapes, or other nonconductive areas. Furthermore, the conductive layer 45 may be a
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smooth or substantially smooth surface, or may be rough or pitted. For example, the conductive
layer 45 may be formed by embossing, stamping, filing, sandblasting, holes or irregularities on
the surface, even if deposited with a desired degree of "orange peel". It may or may be provided
with a texture.
[0027]
The conductive layer 45 does not have to be disposed exclusively for the support plate 49.
Instead, in an embodiment, the conductive layer 45 may be deposited on a member that provides
another function, such as a member of a part of the speaker housing. Also, the conductive layer
45 can be deposited directly on the wall or other place where the emitter is attached.
[0028]
The conductive layer 46 provides another role of the emitter. The conductive layer may be
implemented as a metallized film, which is deposited on a film substrate (not separately shown).
The substrate may be, for example, polypropylene, polyimide, polyethylene terephthalate (PET),
biaxially oriented polyethylene terephthalate (eg, Mylar, Melinex or Hostaphan), Kapton, or other
substrate. In one embodiment, the substrate has low conductivity and acts as an insulator
between the conductive surface 45 and the conductive surface 46 when the substrate is located
between the layers 45 and 46 of the conductive surface.
[0029]
Further, in one embodiment, conductive surface 46 (and its insulating substrate, if included) is
separated from conductive surface 45 by insulating layer 47. Insulating layer 47 may be made
of, for example, PET, axially oriented polyethylene terephthalate, biaxially oriented polyethylene
terephthalate, polyethylene, polyimide, or other insulating film or other material.
[0030]
If the distance between conductive surface 46 and conductive surface 45 is too thin to drive the
emitter with sufficient power to obtain sufficient ultrasonic pressure levels, arcing may occur.
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However, if the spacing is too far, the emitter will not resonate. In one embodiment, the
insulating layer 47 is a layer about 0.92 mil (23.368 μm) thick. In one embodiment, the
insulating layer 47 is a layer of about 0.90 mils (22.86 μm) to about 1 mil (25.4 μm) thick. In
another embodiment, the insulating layer 47 is a layer having a thickness of about 0.75 mil
(19.05 μm) to about 1.2 mil (30.48 μm). In yet another embodiment, the insulating layer 47 is
a layer about 0.33 mil (8.382 μm) or 0.25 mil (6.35 μm) thin. Other thicknesses may be used.
In one embodiment, the insulating layer 47 is not provided separately. For example, one
embodiment relies on the insulating substrate of conductive layer 46 (eg, as in the case of a
metallized film) to provide an insulator between conductive surfaces 45 and 46. One benefit of
including the insulating layer 47 is to allow higher levels of bias voltage to be applied across the
first and second conductive surfaces 45, 46 without arcing. When considering the insulating
properties of the material between the two conductive surfaces 45, 46, the insulating value of the
layer 47, when included, and the insulation of the substrate on which the conductive layer 46 is
deposited, if any Values must be considered.
[0031]
The grating 48 is included at the top of the stack. The grating 48 can be made of conductive or
non-conductive material. In one embodiment, the grating 48 may be a grating that forms an
external speaker grating of the speaker. Since the gratings 48 are in contact with the conductive
surface 46 in an embodiment, they may be made using non-conductive materials to protect the
user from the bias voltage present on the conductive surface 46. The grating 48 may have holes
51, slots or other openings. These openings may be uniform or may vary over the area.
Alternatively, the openings may be through openings extending from one surface of grating 48 to
the other surface. The gratings 48 may be of various thicknesses. For example, the grating 48
may be about 60 mils (1.524 mm), and other thicknesses may be used.
[0032]
Electrical contacts 52a, 52b are used to connect the modulated carrier signal to the emitters.
Examples of emitter drive circuits are described below.
[0033]
FIG. 4 is a schematic diagram illustrating a cross-sectional view of the assembled emitter in
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10
accordance with the example illustrated in FIG. As shown, this embodiment comprises a support
plate 49, a conductive surface 45, a conductive surface 46 (comprising a conductive surface 46a
deposited on a substrate 46b), an insulating layer 47 between the conductive surface 45 and the
conductive surface 46a, And grating 48. The dimensions of these and other figures, and in
particular the thicknesses of the layers, are not drawn to scale.
[0034]
The emitter can be made in any dimension. In some applications, the emitter may be 10 inches
long (15.4 cm) by 5 inches wide (.omega.), But larger or smaller dimensions are possible. The
actual ranges of length and width may be equivalent to conventional bookshelf speakers. Larger
emitter areas can result in greater audio output but may require higher bias voltages.
[0035]
Table 1 describes examples of metallized films that may be used to provide the conductive
surface 46. For conductive surface 46, low sheet resistance or low ohms / square is preferred.
Thus, the films of Table 1 having <5 ohms / square and <1 ohms / square exhibited higher
performance than high ohms / square resistance films. Films exhibiting ohms / square greater
than 2k or 2k did not provide high power levels in development testing. Kapton is a desirable
material because it is relatively temperature insensitive in the temperature range expected for
emitter operation. Polypropylene is less desirable because of its relatively low capacitance. Low
capacitance at the emitter means that a larger inductance (and thus physically larger inductor) is
required to form a resonant circuit. As Table 1 illustrates, the film used to provide the conductive
surface 46 is in the range of about 0.25 mil (6.35 μm) to 3 mil (76.2 μm), including the
substrate.
[0036]
Although not shown in Table 1, another film that may be used to provide the conductive surface
46 is the DE320 aluminum / polyimide film available from Dunmore Corporation. This film is a
polyimide-based product and is coated on both sides with aluminum. This film is about 1 mil
(25.4 μm) thick and <1 ohm / square. As these examples show, the conductive surfaces 45, 46
can be any of a number of different metallized films. The metallization is typically performed
using sputtering or physical vapor deposition. It should be noted that aluminum, nickel,
04-05-2019
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chromium, copper, or other conductive materials may be used as the metal layer, with low ohms
/ square materials being more preferred.
[0037]
Films integrated with metallized films or backing plates typically have a unique resonant
frequency at which they will resonate. For certain film / support plate combinations, the inherent
resonant frequency may be in the range of about 30 kHz to 150 kHz. For example, for the
backing plate described above, an approximately 0.33 mil (8.382 μm) Kapton film resonates at
approximately 54 kHz, while an approximately 1.0 mil (25.4 μm) Kapton film resonates at
approximately 34 kHz. Thus, the carrier frequencies of the film and the ultrasound carrier can be
chosen such that the carrier frequency matches the resonant frequency of the film / support
plate combination. By selecting the carrier frequency of the resonant frequency of the film /
support plate combination, the output of the emitter can be increased. For example, in one
embodiment, the carrier frequency may be selected to be completely or substantially the same
frequency as the resonant frequency of the film / support plate combination. In another
embodiment, the carrier frequency may be selected within the predetermined range of the
resonant frequency of the emitter. For example, in one embodiment, the carrier frequency may
be selected within +/- 15% of the resonant frequency of the film / support plate combination. In
yet another embodiment, the resonant frequency of the emitter is within +/- 25% of the
frequency of the ultrasound carrier signal. In yet another embodiment, the resonant frequency of
the emitter is within +/- 5% of the frequency of the ultrasound carrier signal. In yet another
embodiment, the resonant frequency of the emitter is within +/- 10% of the frequency of the
ultrasound carrier signal.
[0038]
FIG. 5 is a schematic diagram illustrating another example configuration of an ultrasound emitter
in accordance with one embodiment of the presently described technology. The example of FIG. 5
includes conductive surfaces 45, 46 and gratings 48. The difference between the embodiment
shown in FIG. 5 and the embodiments shown in FIGS. 3 and 4 is that the embodiment of FIG. 5
does not include a separate insulating layer 47. Layers 45, 46 and 48 can be implemented using
the same materials as described for FIGS. 3 and 4 above. Specifically, the conductive surface 46 is
deposited on a substrate of insulating properties to avoid shorting or arcing between the
conductive surfaces 45,46. For example, a metallized Mylar or Kapton film, such as the film
shown in Table 1, is used to implement the conductive surface 46 in an orientation such that the
insulating substrate is between the conductive surfaces 45, 46. it can.
04-05-2019
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[0039]
FIG. 6a is a schematic diagram illustrating an example of a simple drive circuit that can be used
to drive the emitter disclosed herein. As will be appreciated by those skilled in the art, when
multiple emitters are used (e.g., for stereo applications, etc.), each emitter may be provided with a
drive circuit 50. In one embodiment, drive circuit 50 is provided in the same housing or assembly
as the emitter. In another embodiment, the drive circuit 50 is provided in another housing.
[0040]
The modulated signal from signal processing system 10 is typically electronically coupled to the
amplifier (not shown). The amplifier may be part of drive circuit 50 or may be in the same
housing or housing as drive 50. Alternatively, the amplifiers can be housed independently. After
amplification, the signal is transmitted to the inputs A1, A2 of the drive circuit 50. In the
embodiments described herein, the emitter assembly includes an emitter operable at ultrasound
frequencies. Emitters (not shown in FIG. 6) are connected to the drive circuit 50 at contacts D1,
D2. The inductor 54 forms a resonant circuit in parallel with the emitter. By arranging the
inductor 54 in parallel with the emitter, it can be realized that the current circulates through the
inductor, the emitter and the parallel resonant circuit. That is, the lower capacitance value
requires more inductance to achieve resonance at the desired frequency, so the capacitance of
the emitter is important. Thus, the capacitance values of the layers and emitters may be an
important consideration in the design of the emitter as a whole.
[0041]
Placing inductor 54 in parallel with the emitter can provide advantages over series placement.
For example, in this configuration it is possible to achieve resonance in the inductor-emitter
circuit without the presence of an amplifier directly in the current path. This, in addition to the
more stable and predictable performance of the emitter, can result in reduced power dissipation
as compared to a series arrangement.
[0042]
Obtaining resonance at optimal system performance may increase system efficiency (ie, reduce
04-05-2019
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system power consumption) and reduce heat generated by the system.
[0043]
In a series arrangement, the circuit causes waste current to flow through the inductor.
As known in the art, the emitter will perform best at (or near) the point at which electrical
resonance is realized in the circuit. However, the amplifier causes changes in the circuit, which
can vary due to temperature, signal dispersion, system performance, etc. Thus, when the inductor
54 is arranged in series with the emitter (and amplifier), it may be more difficult to obtain (and
maintain) a stable resonance.
[0044]
Inductor 54 may be of various types known to those skilled in the art. However, the inductor
produces a magnetic field that can "leak" out of the range of the inductor. This magnetic field can
interfere with the operation and / or reaction of the emitter. Also, many of the inductor / emitter
pairs used in ultrasound applications operate at voltages that generate large amounts of thermal
energy. Also, heat can adversely affect the performance of parametric emitters.
[0045]
For at least these reasons, in most conventional parametric voice systems, the inductor is
physically located very far from the emitter. This solution addresses the issues outlined above,
but adds another factor of complexity. The signal transferred from the inductor to the emitter
can be at a relatively high voltage (160 Vpp or higher). Thus, the wire connecting the inductor to
the emitter should be of high voltage application. Also, in some configurations, long wires may be
required, but may be expensive as well as dangerous and may interfere with communication
systems not related to parametric emitter systems.
[0046]
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Inductor 54 (including components as shown in the structure of FIG. 6a) may be implemented
using a pot core inductor. The pot core inductor is typically formed of a ferrite material and is
contained within the pot core. This is what confines (limits) the inductor winding and the
magnetic field generated by the inductor. Typically, the pot core includes two ferrite segments
59a, 59b that define a cavity 60 in which the inductor winding can be disposed. See Figure 6b.
Voids G may be included to improve the permeability of the pot core without affecting the
shielding ability of the core. Thus, by increasing the size of the air gap G, the permeability of the
pot core is improved. However, the increase in the size of the air gap G requires an increase in
the number of turns (turns) of the inductor held in the pot core in order to achieve an inductance
of a desired size. Thus, the air gap can reduce the heat generated by the pot core inductor while
at the same time improving the permeability without compromising the shielding properties of
the core.
[0047]
In the example illustrated in FIG. 6a, a binary step-up transformer (step-up transformer) is used.
However, primary winding 55 and secondary winding 56 may be combined with what is
commonly referred to as an autotransformer structure. Either or both primary and secondary
windings may be included in the pot core.
[0048]
As noted above, it is desirable to implement a resonant circuit in parallel with the inductor 54
and the emitter. Furthermore, it is also desirable that the impedance of the inductor / emitter
pair match the impedance required by the amplifier. This generally requires an increase in the
impedance of the inductor / emitter pair. Furthermore, it may be desirable to place the inductor
physically near the emitter to achieve these goals. Thus, in one embodiment, the air gap of the
pot core is selected such that the number of turns of the primary winding 55 represents the
impedance load required of the amplifier. Thus, each loop of the circuit is wound to operate at
high efficiency. The increase in pot core air gap results in the ability to increase the number of
turns of inductor element 55 without changing the desired inductance of inductor element 56
(which can affect the emitter loop resonance), as well as required by the amplifier To adjust the
number of turns of the inductor element 55 to match the impedance load.
[0049]
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An additional benefit from the increase in void size is that the physical size of the pot core can be
reduced. Thus, a smaller pot core transformer can be used while providing the same inductance
to create resonance with the emitter.
[0050]
The use of a step-up transformer brings additional advantages to the system. Since the
transformer "steps up" from the direction of the amplifier to the emitter, it necessarily "steps
down" from the direction of the emitter to the amplifier. In this way, negative feedback, which
can move from the inductor / emitter pair to the amplifier, is reduced by the bucking process,
thus generally minimizing the effects of such events on the amplifier and system (among other
things, Changes in the inductor / emitter pair that may affect the impedance load experienced by
the amplifier are reduced).
[0051]
In one embodiment, an enameled litz wire 30/46 is used for the primary and secondary
windings. The litz wire consists of a large number of fine strands of yarn, which are individually
insulated, twisted together or braided. The Litz wire uses a plurality of thin, individually insulated
conductors in parallel. The diameters of the individual conductors are chosen to be smaller than
the skin depth at the operating frequency. By doing so, the yarn does not suffer from any
significant skin effect losses. Thus, the litz wire enables better performance at higher frequencies.
[0052]
Bias voltages are applied to terminals B1 and B2 to bias the emitters. The full wave rectifier 57
and the filter capacitor 58 provide a DC bias to the circuit opposite the emitter inputs D1, D2.
The bias voltage used is ideally about twice (or more) the reverse bias expected to be applied to
the emitter. This ensures that a sufficient bias voltage will cause the emitter to come out of the
reverse bias state. In one embodiment, the bias voltage is about 420 volts. In alternative
embodiments, other bias voltages may be used. In ultrasound emitters, the bias voltage is
typically in the range of hundreds of volts.
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[0053]
Although not shown in the drawings, arcing may occur between the conductive layers 45, 46 if
the bias voltage is high enough. This arcing can occur at the middle insulating layer and at the
end of the emitter (around the outer edge of the insulating layer). Thus, the insulating layer 47
may be larger in length and width than the conductive surfaces 45, 46 to prevent arcing at the
ends. Similarly, when the conductive layer 46 is a metallized film on an insulating substrate, the
conductive layer 46 is longer than the conductive layer 45 in order to increase the distance from
the end of the conductive layer 46 to the end of the conductive layer 45 And may be large in
width.
[0054]
A resistor R1 can be included to reduce or flatten the element Q of the resonant circuit. The
resistance R1 is not necessary in all cases, air as a load will of course lower the Q. Similarly, the
narrower litz wire in inductor 54 can also lower Q, so the peak does not become too sharp.
[0055]
FIG. 7 is a schematic diagram illustrating another example emitter configuration according to one
embodiment of the presently described technology. The emitter of this configuration includes a
conductive grating 65 as a bottom layer, an insulating intermediate layer 47 and a top
conductive layer 46. Layers 46 and 47 may be implemented using the examples of layers 46 and
47 described above with reference to FIGS. 3 and 4. The conductive grating 65 may be made
using a conductive material or a material having a conductive surface or coating. Input lead 52b
is connected to conductive grating 65, as conductive grating 65 forms one of the emitter
electrodes.
[0056]
The conductive gratings 65 may have a pattern of holes, slots or other openings. In one
embodiment, the openings constitute about 50% of the area of conductive grating 65. In another
embodiment, the openings constitute the area of the conductive grating 65 in a larger or smaller
04-05-2019
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proportion. The conductive grating 65 may be about 60 mils (1.524 mm) thick. In another
embodiment, the conductive gratings 65 may be of different thicknesses.
[0057]
FIG. 8 is a schematic diagram illustrating another example emitter configuration according to one
embodiment of the presently described technology. The emitter of this configuration includes a
conductive grating 65 as a bottom layer, an insulating intermediate layer 47, a top conductive
layer 46 and a top grating 48. The emitter illustrated in FIG. 8 is similar to the example
illustrated in FIG. 7 but with gratings 48 added.
[0058]
The layers that make up the emitters described herein can be combined using a number of
different techniques. For example, frames, clamps, clips, adhesives, or other attachment
mechanisms may be used to bond the layers. The layers can be bonded at their ends to avoid
disturbing the resonance of the emitter film.
[0059]
The conductive and nonconductive layers that make up the various emitters disclosed herein can
be made using flexible materials. For example, the embodiments described herein use a flexible
metallized film to form the conductive layer and use a non-metallized material to form the
resistive layer. Due to the flexible nature of these materials, they are molded and formed into the
desired configuration and shape.
[0060]
For example, as illustrated in FIG. 9A, the layers are attached to the substrate 74 in an arched
(arched) configuration. FIG. 10a is a perspective view of an emitter formed in an arched
configuration. In this example, the support material 71 is molded or formed into an arch shape,
on which the emitter layer 72 is attached. Another example is cylindrical (see FIGS. 9 b and 10 b)
and spheres. As will be apparent to those skilled in the art after reading this description, other
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shapes of substrates or substrates may be used to form an ultrasound emitter thereon in
accordance with the techniques disclosed herein. .
[0061]
Mylar, Kapton, and other metallized films can be tensioned and stretched to some extent. Also,
stretching the film and using the film in a stretched configuration helps to the high directivity of
the emitter. Essentially, ultrasound signals tend to be directional. However, stretching of the film
provides an even higher level of directivity.
[0062]
The conductive layer may be made using any of a number of conductive materials. Conductive
materials that may generally be used include aluminum, nickel, chromium, gold, germanium,
copper, silver, titanium, tungsten, platinum and tantalum. Conductive metal alloys may also be
used.
[0063]
As mentioned above, the conductive layers 45, 46 can be made using a metallized film. These
include Mylar, Kapton and other similar films. These metallized films can vary in the degree of
transparency from substantially completely transparent to opaque. Similarly, the insulating layer
47 can be made using a transparent film. Thus, the emitters disclosed herein can be made of a
transparent material that forms a transparent emitter. Such emitters can be placed on top of
various ones and configured to form an ultrasonic speaker. For example, one or a pair (or more)
of transparent emitters may be installed as a transparent film on a television screen. This can be
advantageous as the television is thinner and space for large speakers is reduced. By stacking the
emitters on the television screen, the speakers can be arranged without requiring additional
cabinet space. As another example, the emitter can be placed on the picture frame, replacing the
picture and ultrasound emitters. Also, because the metallized film can be highly reflective, the
ultrasound emitter can be a mirror.
[0064]
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19
While various embodiments of the present invention have been described, it should be
understood that they have been presented by way of example only, and not limitation. Similarly,
various figures illustrate examples of the structural or other configurations of the present
invention. They are illustrated as an aid to understanding the features and functions that can be
included in the present invention. The present invention is not limited to the illustrated structure
or configuration examples, and desired features may be implemented using various other
structures and configurations. In fact, it is obvious to those skilled in the art how to implement
alternative functional, logical or physical partitioning and configuration to implement the desired
features of the present invention. Will. Also, a number of different configuration module names
other than those illustrated herein may be applied to the various sections. Moreover, the order of
the steps set forth herein, with regard to the flow diagrams, operation descriptions, and method
claims, may be varied from one implementation to another in the same order of functionality
described, unless the context indicates otherwise. There is no requirement that the form be
implemented.
[0065]
While the present invention has been described above in terms of various exemplary
embodiments and implementations, the various features, aspects and functionalities described in
one or more of the individual embodiments are set forth. It is not limited to the application to the
particular embodiment being implemented. Rather, one or more of the present inventions
whether or not such embodiments are described, as well as whether or not such features are
meant as part of the described embodiments. The other embodiments of the present invention
can be applied alone or in various combinations. Thus, the breadth and scope of the present
invention are not limited to any of the above-described exemplary embodiments.
[0066]
The terms and phrases used in this document, and variations thereof, unless otherwise expressly
stated, should be construed as open ended as opposed to restricted. As an earlier example, the
term "comprising" should be interpreted as meaning "including without limitation." The term
"example" is used to provide typical items in the discussion and does not provide a complete or
limited inventory of the same. The terms "a" and "an" should be interpreted as meaning "at least
one," "one or more." Also, the adjectives “conventional,” “traditional,” “normal,”
“standard,” “known,” and similar terms limit or limit the described item to a predetermined
period of time. It should not be construed as limiting as an article obtainable during the period of
04-05-2019
20
Rather, it should be construed as covering prior, traditional, conventional, or standard techniques
that are available or known now or for the future. Similarly, this document represents technology
that is obvious or known to those skilled in the art, and such technology covers technologies that
are or will be apparent to those skilled in the art, now or in the future.
[0067]
With respect to terms or phrases that mean expansion, such as “one or more”, “at least
one”, “but not limited to” that exist in some cases, in those cases where there is no language
that means such expansion, Further, limited events should not be construed as intended or
required. The use of the term "module" does not imply that all components or functionalities
described or claimed as part of a module are configured as a common package. In fact, any or all
of the various components of the module, whether they be control logic or other components,
may be combined into a single package or held separately, and further, numerous groupings Or
may be distributed across packages or multiple locations.
[0068]
Additionally, the various embodiments set forth herein are described as exemplary block
diagrams, flow diagrams, and other figures. As will be apparent to those skilled in the art after
reading this document, the illustrated embodiments and their various alternatives may be
implemented without limitation to the illustrated examples. For example, block diagrams and
their associated descriptions should not be construed as requiring a particular structure or
configuration.
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