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JP2005110216

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Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
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DESCRIPTION JP2005110216
The present invention provides a sound reproducing apparatus having an improved sound
reproducing function in the case of adding the sound reproducing function to a device having
another function. A sound reproduction device includes an LCD 20 which is an example of a front
panel, a case 22 and an electromechanical acoustic transducer 23. The LCD 20 performs a
predetermined operation in response to an applied electrical signal. The case 22 forms a space
24 for sound emission with the LCD 20. The electromechanical acoustic transducer 23 is
connected to the case 22 and emits sound into the space 24. Here, when the sound is emitted
from the electromechanical acoustic transducer 23 into the space, the LCD 20 outputs the sound
to the outside by vibrating with the energy of the emitted sound. [Selected figure] Figure 1B
Sound reproduction device and portable terminal device
[0001]
The present invention relates to a sound reproduction apparatus and a portable terminal
apparatus including the same, and more particularly to a sound reproduction apparatus and a
portable terminal apparatus having a function of acoustically driving a panel with sound
pressure.
[0002]
BACKGROUND ART Conventionally, in electronic devices, particularly in portable devices, it has
been important to save the space or reduce the thickness of the device.
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Here, if it is possible to integrally realize an apparatus having a certain function and an apparatus
having another function, space saving can be achieved as a whole. From this point of view, in the
following, the case of adding the sound reproduction function to an apparatus having a certain
function will be considered. Typically, the case of adding a sound reproduction function to a
display device is considered.
[0003]
2. Description of the Related Art Conventionally, there has been considered a technology in
which a display device and a sound reproduction device are integrated (for example, see Patent
Document 1). FIG. 12 is a perspective view showing a conventional display device having a sound
reproduction function. In FIG. 12, the display device 1 includes a display plate 2, an organic
electroluminescence (EL) 3, a film speaker 4, and electrical signal cords 5 and 6. The display
plate 2, the organic EL 3 and the film speaker 4 are integrally formed of an adhesive or the like.
Hereinafter, the operation of the display device 1 will be described.
[0004]
A character etc. are printed on the display board 2, and the display board 2 is irradiated from the
back by organic EL3 to which the voltage was applied from the electric signal code | cord | chord
5. As shown in FIG. As a result, the characters of the display board 2 are displayed. On the other
hand, the film speaker 4 is, for example, a resin film having a piezoelectric action, and vibrates
when an acoustic signal is applied from the electric signal cord 6. As a result, the display plate 2
and the organic EL 3 integrally incorporated with the film speaker 4 are mechanically excited to
generate sound. According to such a display device 1, it is possible to give the user a feeling that
sound is generated from the display screen.
[0005]
In addition, there is a technology which gives the user a feeling that sound is generated from the
display screen in a method different from the above-mentioned technology. Specifically, this is a
technology in which a speaker is provided on the front of the display device to reproduce sound
(see, for example, Patent Document 2). FIG. 13 is a cross-sectional view of a conventional display
device in which a speaker is provided on the front to reproduce sound. In FIG. 13, the display
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device 10 includes a transparent diaphragm 11, a plurality of transparent electrodes 12 formed
on both sides of the transparent diaphragm 11, a support 13, and a Braun tube 14. Hereinafter,
the operation of the display device 10 will be described.
[0006]
A cord (not shown) is connected to each transparent electrode 12 and an electric signal is applied
to each transparent electrode by the cord. The transparent diaphragm 11 is made of a polymeric
piezoelectric sheet material, and vibrates with an electric signal supplied from the transparent
electrode 12 to generate a sound. Since the transparent diaphragm 11 and the transparent
electrode 12 are made of transparent material, the image of the Braun tube is transmitted.
Therefore, it is possible to give the user a feeling that sound is generated from the screen of the
cathode ray tube. Japanese Utility Model Publication No. 01-90086 Japanese Utility Model
Publication No. 03-34391
[0007]
In the display device 1 described above, since the display board 2, the organic EL 3 and the film
speaker 4 are integrally incorporated, the film speaker 4 vibrates the display board and the
organic EL 3 together to reproduce sound. It will be. However, since the three parties integrally
configure the diaphragm, the weight of the diaphragm is increased, and as a result, there is a
problem that the sound pressure level to be reproduced is lowered. Furthermore, by integrating
the three into one, the rigidity of the diaphragm is increased. As a result, it becomes difficult to
vibrate in the low frequency range, and the sound pressure level of the low frequency decreases.
[0008]
On the other hand, in the display device 10, the entire surface of the cathode ray tube 14 is
covered with the transparent diaphragm 11. Further, the space between the cathode ray tube 14
and the transparent diaphragm 11 is kept in a narrow space for space saving. Therefore, since
the acoustic compliance exhibited by the space is very small, reproduction of the low tone range
is difficult in the display device 10.
[0009]
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As described above, conventionally, when the display device and the sound reproduction device
are integrated, there is a problem with the sound quality of the sound reproduction device (in
particular, the sound quality of the bass region). In addition, it is thought that the same problem
will arise if it is going to add an acoustic reproduction function further also in the apparatus
which has not only a display apparatus but another function. That is, when the sound
reproducing function is added by installing the film speaker in an apparatus having another
function, it is considered that the function of the film speaker is deteriorated due to the mass and
rigidity of the apparatus.
[0010]
Therefore, an object of the present invention is to provide a sound reproducing device having an
improved sound reproducing function in the case of adding the sound reproducing function to a
device having another function.
[0011]
The present invention has the following features to achieve the above object.
That is, the present invention is a sound reproduction device provided with a surface panel, a
case, and an electromechanical sound transducer. The front panel performs a predetermined
operation in response to an applied electrical signal. The case forms a space for sound radiation
with the front panel. An electromechanical acoustic transducer is connected to the case and
radiates sound into space. Here, when a sound is emitted from the electromechanical acoustic
transducer into space, the surface panel vibrates with the energy of the emitted sound to output
the sound to the outside.
[0012]
The front panel may be an image display panel that displays an image by an electrical signal.
Typically, the image display panel may be a liquid crystal display. Furthermore, in this case, the
case may support the outer peripheral portion of the LCD by an elastic body. Further, the surface
panel may be a film-like display panel such as an organic EL.
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[0013]
In addition, the front panel may be a sound generation panel that reproduces a sound by an
electrical signal. For example, the sound generation panel is formed of a piezoelectric element.
Also, the sound generation panel may be made of a transparent material.
[0014]
Furthermore, when the front panel is a sound generation panel, the sound reproduction device
may have the following configuration. That is, it may further include a high-frequency range
component extraction unit that extracts a range range component higher than a predetermined
first frequency from the acoustic signal to be reproduced. At this time, the tone generation panel
inputs the signal of the high range component extracted by the high range component extraction
unit. An electromechanical acoustic transducer receives an acoustic signal.
[0015]
In addition, when the front panel is a sound generation panel, the sound reproduction device may
further include a high range component extraction unit and a low range component extraction
unit. The high frequency range component extraction unit extracts a high frequency range
component higher than a predetermined first frequency from the acoustic signal to be
reproduced. The bass range component extraction unit extracts, from the acoustic signal, a
component of a range lower than the second frequency which is a frequency equal to or lower
than the first frequency. At this time, the tone generation panel inputs the signal of the high
range component extracted by the high range component extraction unit. The electromechanical
acoustic converter inputs the signal of the bass component extracted by the bass component
extraction unit.
[0016]
In addition, when the front panel is a sound generation panel, the sound reproduction apparatus
may further include a level adjustment unit. The level adjustment unit adjusts signal levels of at
least one of an acoustic signal to be input to the sound generation panel and an acoustic signal to
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be input to the electromechanical acoustic transducer. Specifically, the reproduction sound
pressure level of the sound generation panel when a predetermined sound signal is input to the
sound generation panel, and the reproduction sound pressure level of the sound generation
panel when the predetermined sound signal is input to the electromechanical sound converter
Adjust the signal level so that is the same degree.
[0017]
In addition, in the case where the front panel is a sound generation panel, the sound
reproduction device may further include a phase adjustment unit. The phase adjustment unit
adjusts the phase of the signal with respect to at least one of the acoustic signal to be input to the
sound generation panel and the acoustic signal to be input to the electromechanical acoustic
transducer. Specifically, the phase of the reproduced sound of the sound generation panel when a
predetermined sound signal is input to the sound generation panel, and the phase of the sound
signal of the sound generation panel when the predetermined sound signal is input to the
electromechanical acoustic transducer The phase of the signal is adjusted so that the phase of the
reproduced sound does not become opposite to the phase in the predetermined frequency band.
[0018]
In addition, the case typically has an acoustic hole, and the electromechanical acoustic transducer
emits sound from the acoustic hole to the space. It may further comprise an acoustic tube
connecting the case and the electromechanical acoustic transducer. At this time, the case has an
acoustic hole at the connection portion with the acoustic tube. Then, the electromechanical
acoustic transducer emits sound from the acoustic hole to the space through the acoustic tube.
[0019]
The electromechanical acoustic transducer is typically driven by at least one of an
electrodynamic type, an electromagnetic type, an electrostatic type, and a piezoelectric type.
[0020]
The front panel may include an image display panel that displays an image by an electrical
signal, and a sound generation panel that is integrally formed with the image display panel and
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that reproduces a sound by an electrical signal.
For example, the image display panel is formed of an organic EL, and the sound generation panel
is formed of a piezoelectric film. Further, the sound generation panel may be provided on the
entire surface of the image display panel, or may be provided only on a part of the surface of the
image display panel.
[0021]
The sound generation panel is driven by any one of an electrodynamic type, an electromagnetic
type, an electrostatic type and a piezoelectric type.
[0022]
Furthermore, the present invention may be provided by the form of an electronic device provided
with a sound reproduction device.
At this time, the image signal to be reproduced is input to the front panel, and the acoustic signal
to be reproduced is input to the electromechanical acoustic transducer. Furthermore, the
electronic device may further include a signal amplification unit that amplifies an acoustic signal
to be reproduced. The signal amplification unit can switch the amplification factor according to a
user's instruction.
[0023]
Furthermore, the present invention may be provided by a form of a portable terminal device
provided with a sound reproduction device. At this time, the portable terminal device further
includes an antenna that receives a reception signal including at least one of an acoustic signal
and an image signal, and a reception signal processing unit that performs predetermined signal
processing on the reception signal. The reception signal processing unit inputs the image signal
to the front panel when the reception signal includes an image signal, and inputs the acoustic
signal to the electromechanical acoustic transducer when the reception signal includes an
acoustic signal. .
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[0024]
The acoustic signal may be a reception signal representing a reception sound. At this time, a
reception signal is input as an acoustic signal to the electromechanical acoustic transducer.
[0025]
The mobile terminal device may further include an amplification unit that amplifies an acoustic
signal to be input to the electromechanical acoustic transducer. The mobile terminal device can
change the amplification factor of the amplification unit.
[0026]
According to the above-described invention, since the sound can be emitted by vibrating the
surface panel itself which performs a predetermined operation, it is possible to realize the
configuration in which the sound reproducing function is added to the device having another
function. Therefore, space saving of equipment can be achieved. Furthermore, by acoustically
driving the front panel, it is possible to reproduce the bass region and improve the acoustic
reproduction function.
[0027]
In addition, a sound reproduction function can be added to an image display apparatus by
making a surface panel into an image display panel. In this case, it is possible to give the user a
feeling that sound is being reproduced from the image. When the image display panel is an LCD,
the case can easily vibrate the LCD by supporting the outer peripheral portion of the LCD with an
elastic body.
[0028]
Further, by setting the surface panel to a sound generation panel such as a piezoelectric element,
it is possible to reproduce a wider band of sound.
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[0029]
Furthermore, by providing the treble range component extraction unit, it is possible to limit the
sound generated by the vibration of the sound generation panel itself to the treble range.
Therefore, the mutual influence of the vibration of the sound generation panel itself and the
vibration by the electromechanical acoustic transducer can be eliminated, and the sound quality
can be improved. Further, in addition to the above, by providing the high-pitched range
component extraction unit, it is possible to reliably limit the sound generated by the vibration by
the electromechanical acoustic transducer to the bass range. Therefore, the mutual influence of
the vibration of the sound generation panel itself and the vibration by the electromechanical
acoustic transducer can be further reduced, and the sound quality can be further improved.
[0030]
Further, by further including a level adjustment unit, the sound pressure level of the sound
generated by the vibration of the sound generation panel itself and the sound generated by the
vibration of the electromechanical acoustic transducer can be made equal. By this, it is possible
to output a wide band sound at the same level, and the sound quality is further improved.
[0031]
Further, by further including the phase adjustment unit, it is possible to prevent the sound
pressure level from being lowered due to the mutual influence of the vibration of the sound
generation panel itself and the vibration by the electromechanical acoustic transducer.
[0032]
Further, by configuring the case to have an acoustic hole, a configuration can be easily realized
that guides the sound emitted from the electromechanical acoustic transducer into space.
Furthermore, by providing the acoustic tube, the electromechanical acoustic transducer can be
installed at any place. Therefore, the degree of freedom in design is increased, and it becomes
possible to realize a more compact sound reproducing apparatus and an electronic device using
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the same.
[0033]
Also, the sound reproducing apparatus can be applied to an electronic device. Furthermore, when
the electronic device includes a signal amplification unit, the surface panel can be used as a
loudspeaker.
[0034]
In addition, the sound reproduction device can be applied to a portable terminal device. For
example, a sound reproducer can be used to reproduce a received signal. Furthermore, by using
the amplification unit, the surface panel is selectively operated as one of a normal form (a form in
which the user uses the ear close to the surface panel) and a form to be used as a speaker for
sound amplification. be able to.
[0035]
Embodiment 1 Hereinafter, a sound reproduction apparatus according to Embodiment 1 will be
described. FIGS. 1A and 1B are diagrams showing a sound reproduction device according to
Embodiment 1. FIG. That is, FIG. 1A is a plan view in which a part of the sound reproduction
device is cut away, and FIG. 1B is a cross-sectional view of the sound reproduction device shown
in FIG. In FIG. 1, the sound reproduction apparatus includes a liquid crystal display (LCD) 20, a
suspension member 21, a case 22, and an electromechanical acoustic transducer 23. As shown in
FIG. 1B, in the first embodiment, an LCD 20 which is an example of an image display panel for
displaying an image is used as a front panel for emitting a sound. In FIG. 1A, a part of the LCD 20
is cut away. The sound reproduction apparatus also includes an electronic circuit for controlling
an image signal supplied to the LCD 20 and an electronic circuit for controlling an acoustic signal
supplied to the electromechanical acoustic transducer 23. Those descriptions are omitted for the
purpose of facilitating the explanation. Similarly, in the embodiments other than the first
embodiment, the description of the electronic circuit and the like not directly related to the
present invention is omitted.
[0036]
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As shown in FIG. 1B, the case 22 has a concave portion in cross section. This portion is
approximately the same size as the LCD 20, and the LCD 20 is mounted on the case 22 in such a
manner as to fit into this portion. The suspension member 21 is an elastic body, and the case 22
is used to support the LCD 20. The suspension member 21 is provided between the case 22 and
the LCD 20 and supports the outer periphery of the LCD 20. That is, the LCD 20 is mounted on
the case 22 by the suspension member 21 such that a space 24 is created between the case 22
and the LCD 20. Further, the case 22 has a hollow inside, and a sound hole 25 is provided in a
portion where the cross section of the case 22 is concave. The electromechanical acoustic
transducer 23 is installed inside the case 22 so as to be coupled to the sound hole 25. Thereby,
the sound hole 25 serves as an acoustic coupling means for transmitting the sound radiated from
the electromechanical acoustic transducer 23 to the space 24. The space 24 is desirably
configured to maintain high airtightness so that the sound emitted from the electromechanical
acoustic transducer 23 does not leak.
[0037]
FIG. 2 is a structural cross-sectional view of the electromechanical acoustic transducer 23 shown
in FIG. 1A. In the first embodiment, an example in which a piezoelectric speaker is used as the
electromechanical acoustic transducer 23 will be described. However, as long as the transducer
system of the electromechanical acoustic transducer 23 has a function of emitting sound from
the diaphragm, any system such as an electrodynamic system, an electromagnetic system, and an
electrostatic system can be used. Similar actions are obtained. Also in the second embodiment
and later, the transducer system of the electromechanical acoustic transducer may be any
system.
[0038]
In FIG. 2, the electromechanical acoustic transducer 23 includes piezoelectric elements 30 and
31, an intermediate electrode 32, lead wires 33, 34 and 35, input terminals 36 and 37, and a
frame 38. The frame 38 is joined to the case 22, and the outer peripheral portion of the
intermediate electrode 32 is supported by the frame 38. The piezoelectric element 30 is attached
to one surface of the intermediate electrode 32, and the piezoelectric element 31 is attached to
the other surface. The piezoelectric elements 30 and 31 are made of, for example, a conductive
material such as phosphor bronze. The lead wire 33 is a lead wire for inputting electricity to the
intermediate electrode 32, and connects the input terminal 37 and the intermediate electrode 32.
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The lead wire 34 is a lead wire for inputting electricity to the piezoelectric element 31, and
connects the input terminal 36 and the piezoelectric element 31. The lead wire 35 is a lead wire
for inputting electricity to the piezoelectric element 30, and connects the input terminal 36 and
the piezoelectric element 30.
[0039]
Next, the operation of the sound reproducing apparatus configured as shown in FIGS. 1A, 1B and
2 will be described. When an electrical signal is applied to the input terminals 36 and 37 of the
electromechanical acoustic transducer 23, the piezoelectric elements 30 and 31 perform bending
vibration, whereby sound is emitted from the intermediate electrode 32 and the piezoelectric
elements 30 and 31. This sound is transmitted to the space 24 by the sound hole 25. As a result,
since the LCD 20 vibrates due to the sound pressure of the space 24, sound is emitted by the
LCD 20. As described above, the LCD 20 performs acoustic reproduction by acoustically driving.
[0040]
Here, the LCD 20 has a relatively heavy weight as compared to the diaphragm of a normal
speaker. However, if the diaphragm area Sd of the electromechanical acoustic transducer 23 is
smaller than the area S1 of the LCD 20, it is possible to reduce the weight of the LCD 20 as
viewed from the diaphragm of the electromechanical acoustic transducer 23. The reason is that
the equivalent weight is proportional to one square of the area ratio (Sd / Sl). That is, by
designing the area Sd of the electromechanical acoustic transducer 23 to be relatively small and
the area Sl of the LCD 20 to be relatively large, it is possible to suppress the decrease in the
sound pressure level. Therefore, even when the heavy LCD 20 is used as a diaphragm for sound
reproduction, it is possible to reproduce the low tone range.
[0041]
Furthermore, the LCD 20, which is a front panel, has a function of reproducing an image by an
image signal. Therefore, the LCD 20 which is the front panel is an image reproduction apparatus
and at the same time, has the function of the sound reproduction apparatus. As described above,
according to the first embodiment, it is possible to realize the sound reproducing apparatus
capable of reproducing the image and the sound simultaneously by the front panel. Such a sound
reproduction apparatus can be applied to electronic devices such as mobile phones, game
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machines, personal computers, and televisions, typically.
[0042]
Note that a method of installing a transparent sound reproducing device in front of the display
device for reproducing an image described above (see FIG. 13). In the case of), there is a problem
that the image may appear unclear. That is, in the display device 10 shown in FIG. 13 described
above, it is necessary to make the image displayed on the Braun tube 14 look as clear as possible
to the viewer, so the transparent diaphragm 11 installed in front of the display device The
transparent electrode 12 needs to be made of a material having as high a transmittance as
possible. However, since the transmittance of the transparent diaphragm 11 and the transparent
electrode 12 is limited, the sharpness of the image displayed on the Braun tube 14 is also limited.
On the other hand, according to the first embodiment, since the sound is reproduced by the
surface panel itself that reproduces an image, it is not necessary to dispose a transparent
member in front of the surface panel for sound generation. Therefore, the image can be made
clearer than the method of installing a transparent sound reproducing device in front of the
device for reproducing the image. Furthermore, according to Embodiment 1, the thickness can be
further reduced as compared with the configuration in which the transparent diaphragm is
provided in front of the display device.
[0043]
Second Embodiment The following describes a sound reproduction device according to a second
embodiment. FIGS. 3A and 3B are diagrams showing a sound reproduction apparatus according
to Embodiment 2. FIG. That is, FIG. 3A is a plan view in which a part of the sound reproduction
device is cut away, and FIG. 3B is a cross-sectional view of the sound reproduction device shown
in FIG. In FIG. 3A and FIG. 3B, the sound reproduction apparatus includes film-like organic
electroluminescence (EL) 40, a case 41, and an electromechanical acoustic transducer. As shown
in FIG. 3A, in the second embodiment, the organic EL 40 is used as a surface panel that emits a
sound. In FIG. 3A, a part of the organic EL 40 is cut away.
[0044]
The configuration of the sound reproduction apparatus shown in FIG. 3A differs from that of
Embodiment 1 in that a film-shaped organic EL 40 is used as a surface panel instead of the LCD
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20. In FIG. 3A and FIG. 3B, the organic EL 40 has the outer peripheral portion fixed directly to
the case 41 (without the suspension member) on the fixing surface 45. The case 41 is selected to
be more rigid than the organic EL 40. Further, as in the first embodiment, a space 43 is provided
between the case 41 and the organic EL 40. The configurations of the case 41 and the
electromechanical acoustic transducer 42 are the same as the configurations of the case 22 and
the electromechanical acoustic transducer 23 shown in FIG. 1A.
[0045]
The operation of the sound reproducing apparatus configured as shown in FIGS. 3A and 3B will
be described. The sound generated from the electromechanical acoustic transducer 42 is
transmitted to the space 43 by the sound hole 44. Here, among the case 41 forming the space 43
and the organic EL 40, the organic EL 40 has a small rigidity. Therefore, it is the organic EL 40
that vibrates by the energy (sound pressure) of the sound emitted from the electromechanical
acoustic transducer 42 to the space 43. That is, the organic EL 40 is acoustically driven by the
electromechanical acoustic transducer 42 to vibrate. A sound is generated as the organic EL 40
vibrates.
[0046]
In the second embodiment, the organic EL 40 having a rigidity smaller than that of the case 41 is
used as the surface panel, instead of the LCD which is structurally close to a rigid body and heavy
in weight. Thus, no suspension member is required at the outer peripheral portion of the organic
EL 40, and the outer peripheral portion of the organic EL 40 can be directly joined to the case
41. Therefore, the structure can be simplified as compared to the case of using an LCD. In
addition, the device can be thinner than in the case of using an LCD. Furthermore, since the
weight of the organic EL 40 is lighter than that of an LCD, sound can be reproduced more
efficiently than in the case of using an LCD, and high-frequency reproduction can be facilitated.
[0047]
According to the configuration shown in FIGS. 3A and 3B, the organic EL 40 as the front panel is
an image reproduction device and at the same time, has the function of the sound reproduction
device. As described above, according to the second embodiment, it is possible to realize the
sound reproducing apparatus capable of reproducing the image and the sound simultaneously by
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the front panel. As in the first embodiment, such a sound reproduction device can be typically
applied as an electronic device such as a mobile phone, a game machine, a personal computer,
and a television. Also, as in the first embodiment, a method of installing a transparent sound
reproducing device in front of the device for reproducing an image (see FIG. 13). The image can
be shown more clearly than). Furthermore, as in the first embodiment, the thickness can be
further reduced as compared with the configuration in which the transparent diaphragm is
provided in front of the display device.
[0048]
In the second embodiment, one electromechanical acoustic transducer 42 is provided on the
back of the organic EL 40. However, two electromechanical acoustic transducers may be
provided separately. At this time, the signal of the left channel of the stereo signal is input to one
of the electromechanical acoustic transducers, and the signal of the right channel of the stereo
signal is input to the other of the electromechanical acoustic transducers. Thereby, stereo sound
can be reproduced simultaneously with the image from the film-like organic EL.
[0049]
Third Embodiment The following describes a sound reproduction device according to a third
embodiment. FIG. 4A and FIG. 4B are diagrams showing a sound reproduction apparatus
according to the third embodiment. That is, FIG. 4A is a plan view of the sound reproduction
apparatus, and FIG. 4B is a cross-sectional view of the sound reproduction apparatus shown in
FIG. 4A taken along line E-F. In FIGS. 4A and 4B, the sound reproducing apparatus includes a
case 50, a film-like transparent diaphragm 51, a transparent electrode 52, an LCD 53, an
electromechanical acoustic transducer 54, and an acoustic tube 55. As shown in FIG. 4B, in the
third embodiment, a speaker is used as the front panel. And LCD53 which is a display apparatus
is provided in the back of a speaker.
[0050]
The transparent diaphragm 51 is made of, for example, a piezoelectric element such as a
polymeric piezoelectric sheet material. The transparent electrode 52 is bonded to both sides of
the transparent diaphragm 51. The transparent diaphragm 51 and the transparent electrode 52
constitute a transparent film-like speaker 58. The outer peripheral portion of the speaker 58 is
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fixed to the case 50 on the fixing surface 59. The case 50 supports the LCD 53. As shown in FIG.
4A, the LCD 53 is arranged so that the display unit (image displayed on the display unit) can be
seen through from the outside of the sound reproduction apparatus. Although shown by dotted
lines in FIG. 4A, since the speaker 58 is transparent, in practice, the LCD 53 and the fixed surface
59 can be seen through from the outside of the sound reproducing apparatus. A space 56 is
provided between the speaker 58 and the LCD 53. Further, in the case 50, a sound hole 57 is
provided in a portion facing the space 56. One of the openings of the acoustic tube 55 is
connected to the sound hole 57, and the other is connected to the electromechanical acoustic
transducer 54. The acoustic tube 55 transmits the sound emitted by the electromechanical
acoustic transducer 54 from the sound hole 57 to the space 56. That is, the acoustic tube 55
plays a role of acoustically joining the electromechanical acoustic transducer 54 and the sound
hole 57.
[0051]
FIG. 5 is a structural cross-sectional view of the electromechanical acoustic transducer 54 shown
in FIG. 4A. In the third embodiment, an example using an electrodynamic speaker as the
electromechanical acoustic transducer 54 will be described. However, as described above, the
transducer type of the electromechanical acoustic transducer 54 may be any type such as a
piezoelectric type, an electromagnetic type, an electrostatic type, etc. as long as it has a function
of emitting sound from the diaphragm. The same effect is obtained even if
[0052]
In FIG. 5, the electromechanical acoustic transducer 54 includes a bowl-shaped yoke 60, a
magnet 61 provided at a central portion of the yoke 60, a plate 62 disposed on the upper surface
of the magnet 61, and a central portion of the yoke 60. A frame 66 fixed to the outer peripheral
lower surface, a diaphragm 65 whose outer peripheral portion is fixed to the frame 66, and a
voice coil 64 joined to a central portion of the diaphragm 65 are provided. A magnetic space 63
is formed between the inner peripheral surface of the yoke 60 and the outer peripheral surface
of the plate 62. The voice coil 64 is joined to the diaphragm 65 so as to be disposed in the
magnetic space 63. The top surface of the frame 66 is attached to the acoustic tube 55 such that
the electromechanical acoustic transducer 54 blocks the opening of the acoustic tube 55.
[0053]
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Next, the operation of the sound reproducing apparatus configured as shown in FIGS. 4A, 4B and
5 will be described. Here, the speaker 58 in the third embodiment emits sound by two operations
of an operation driven acoustically by the electromechanical acoustic transducer 54 and an
operation driven by the transparent electrode 52. First, an operation driven acoustically by the
electromechanical acoustic transducer 54 will be described.
[0054]
When an electric signal is applied to the voice coil 64 inserted in the magnetic space 63 of the
electromechanical acoustic transducer 54, a driving force is generated in the voice coil 64 and
the diaphragm 65 coupled to the voice coil 64 vibrates. A sound is generated. The sound radiated
from the diaphragm 65 is transmitted from the sound hole 57 to the space 56 through the
acoustic tube 55. As a result, the film-like speaker 58 whose outer peripheral portion is fixedly
supported is acoustically driven and vibrated by the sound pressure of the space 56, and the
vibration reproduces sound.
[0055]
Next, an operation driven by the transparent electrode 52 will be described. A lead wire (not
shown) is connected to the transparent electrode 52, and an electric signal is input to the
transparent diaphragm 51 through the transparent electrode 52 from the lead wire. The
transparent diaphragm 51, which is a polymer piezoelectric sheet material, generates a sound by
bending and vibrating according to the electric signal.
[0056]
As described above, the speaker 58 in the present embodiment is called a driving method in
which the speaker 58 is acoustically driven by the sound pressure of the electromechanical
acoustic transducer 54 (hereinafter, referred to as “first driving method”. The drive method
(hereinafter, referred to as “second drive method”) generates sound and drives by itself by
applying an electric signal. Generate a sound by). Here, depending on the first driving method, it
is generally difficult to reproduce the high tone range. That is, the first driving method is based
on the principle that the speaker 58 is vibrated by the sound pressure of the space 56. However,
the space 56 has a property of acting as a high-range cut acoustic filter for attenuating high
11-05-2019
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range. Therefore, in the first driving method, reproduction of the high range is essentially
difficult. Note that the width of the space 56 (the distance between the front panel and the LCD).
In FIG. 4, the length in the vertical direction. Although it is possible to improve the sound
pressure level in the high range by narrowing the), the operation principle of the first driving
method has an inherent limitation in the reproduction of the high range.
[0057]
On the other hand, it is generally difficult to reproduce the bass range depending on the second
driving method. The reason is that the characteristic of the piezoelectric element itself is a
characteristic that the sound pressure level in the low range becomes low. In addition, if the
width of the space 56 on the back of the speaker 58 is narrowed for the purpose of saving the
space of the device and for the purpose of improving reproduction in the high frequency range in
the first driving method, the compliance of air is reduced.
[0058]
Therefore, in the third embodiment, by using the first and second driving methods in
combination, wide band reproduction from the low tone range to the high tone range is enabled.
Specifically, for the bass range, the bass 58 is reproduced by the acoustic drive of the
electromechanical acoustic transducer 54 due to the sound pressure of the electromechanical
acoustic transducer 54, and for the treble range, the loudspeaker 58 directly vibrates. The treble
is played.
[0059]
In this case, a band (hereinafter referred to as “the band in which the band which can be
reproduced by the first driving method (the band on the bass side) and the band which can be
reproduced by the second driving method (the band on the high band) overlap It is called
"overlapping band". ), The sound pressure level of the reproduced sound may be reduced.
Specifically, when the phase of the vibration of the speaker 58 according to the first driving
method and the phase of the vibration of the speaker 58 according to the second driving method
are opposite to each other, the sound pressure level of the reproduced sound in the overlapping
band decreases. Resulting in. Therefore, it is preferable to perform predetermined signal
processing on input signals used for the two driving methods. Hereinafter, the details of the
11-05-2019
18
signal processing will be described.
[0060]
FIG. 6 is a block diagram showing the function of performing signal processing in the sound
reproduction apparatus according to the third embodiment. As shown in FIG. 6, the sound
reproduction apparatus includes a signal processing unit 70 that performs signal processing on
the sound signal to be reproduced. The signal processing unit 70 includes a low pass filter (LPF)
71, a high pass filter (HPF) 72, a phase adjustment unit 73, and a level adjustment unit 74. The
signal processing unit 70 inputs two acoustic signals. Here, the two acoustic signals are the same
signal, one acoustic signal is input to the HPF 72, and the other acoustic signal is input to the LPF
71. Further, one signal output from the signal processing unit 70 is input to the transparent
electrode 52, and the other signal is input to the electromechanical acoustic transducer 54.
[0061]
The LPF 71 extracts a bass component from the acoustic signal. The cutoff frequency of the
frequency to be extracted is set to the frequency of the sound that can be generated by the first
driving method. That is, the frequency is set to a frequency at which the speaker 58 can be
driven by the first driving method. On the other hand, the HPF 72 extracts high frequency range
components from the acoustic signal. The cutoff frequency of the frequency to be extracted is set
to the frequency of the sound that can be generated by the second driving method. That is, the
frequency is set to a frequency at which the speaker 58 can be driven by the second driving
method. Further, the cutoff frequency of the LPF 71 is set to a frequency lower than the cutoff
frequency of the HPF so that the frequency band of the signal passing through the LPF 71 and
the frequency band of the signal passing through the HPF 72 do not overlap. When it is assumed
that the LPF 71 and the HPF 72 are ideal filters, the cutoff frequencies of the HPF 72 and the
LPF 71 may be the same. Thus, only a signal having a frequency lower than a predetermined
frequency (cutoff frequency) is input to the electromechanical acoustic transducer 54, and only a
signal having a frequency higher than the predetermined frequency is input to the transparent
electrode 52. It becomes.
[0062]
As described above, only the vibration according to the first driving method is given to the
11-05-2019
19
speaker 58 with respect to the low tone range, and the vibration according to the second driving
method is given to the speaker 58 with respect to the high tone range. Thus, by eliminating the
overlap band, it is possible to prevent the sound pressure level from decreasing in the overlap
band. Generally, the sound pressure level of the reproduced sound according to the first driving
method has a characteristic that the sound pressure level rapidly drops at a certain frequency.
Therefore, the sound pressure level of the reproduced sound by the first driving method may be
sufficiently lowered without using the LPF in the high frequency range. In such a case, the signal
processing unit 70 may be configured to include only the HPF (do not include the LPF).
[0063]
Next, the process of adjusting the phase of the signal will be described. The signal output from
the HPF 72 and the signal output from the LPF 71 are input to the phase adjustment unit 73. The
phase adjustment unit 73 adjusts the phase of at least one of the two input signals. Specifically,
adjustment is made so that the phases of the two signals do not become opposite in the overlap
band. This also makes it possible to prevent the sound pressure level from decreasing in the
overlapping band.
[0064]
Note that only one of the method of using the HPF 72 and the LPF 71 and the method of
adjusting the phase may be performed. Even if only one of them is used, it is possible to prevent
the sound pressure level from decreasing in the overlapping band.
[0065]
Next, the process of adjusting the signal level will be described. Here, even if the same signal is
input to the electromechanical acoustic transducer 54 and the transparent electrode 52, the
sound pressure level when the speaker 58 is acoustically driven by the electromechanical
acoustic transducer 54 The sound pressure level when the speaker 58 itself is driven by the
transparent electrode 52 is not necessarily the same. If the two are different, a loud sound will be
produced only in the bass range, or conversely, a loud sound will be produced only in the treble
range. The level adjustment unit 74 is a process for adjusting the signal so that the sound
pressure level becomes the same level in the low range and the high range. Details will be
described below.
11-05-2019
20
[0066]
The two signals output from the phase adjustment unit 73 are input to the level adjustment unit
74. The level adjustment unit 74 adjusts the level of at least one of the two input signals.
Specifically, the sound pressure level when the speaker 58 is acoustically driven by the
electromechanical acoustic transducer 54 and the sound pressure level when the speaker 58
itself is driven by the transparent electrode 52 become approximately the same. Adjust the level
of the signal. This makes it possible to reproduce sounds of similar magnitude in the bass and
treble ranges.
[0067]
In the above, by performing signal processing on the acoustic signal, the problem that the sound
pressure level falls in the overlapping band or the problem that the sound pressure level differs
between the low tone range and the high tone range is prevented. Here, in other embodiments,
these problems may be prevented by adjusting the characteristics of the sound reproducing
apparatus. For example, by changing the width of the space 56, the reproducible frequency band
can be adjusted by the first driving method. Further, for example, by changing the ratio of the
area of the speaker 58 to the area of the diaphragm 65, the sound pressure level of the
reproduced sound according to the first driving method can be adjusted. Similarly to this, by
adjusting the characteristics of the transparent diaphragm 51 and the transparent electrode 52,
it is possible to adjust the frequency band reproducible by the second driving method and the
sound pressure level of the reproduced sound.
[0068]
As described above, according to the third embodiment, it is possible to give the user a feeling
that sound is being reproduced from the display surface of the display device, and it is possible
to reproduce in a wide band by using the front panel as a speaker. It becomes.
[0069]
The sound reproduction device according to the third embodiment enables high-quality sound
reproduction even if the display device (LCD 53) is not provided.
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21
Therefore, the method of driving the speaker described in the third embodiment can obtain
effective effects not only in the case of simultaneously reproducing images and sounds but also
in the case of only high-quality sound reproduction. Hereinafter, in the fourth embodiment, a
sound reproduction apparatus in the case where only high-quality sound reproduction is
intended will be described.
[0070]
Fourth Embodiment The following describes a sound reproduction device according to a fourth
embodiment. As described above, in the fourth embodiment, the driving method of the sound
reproducing apparatus according to the third embodiment is applied to a sound reproducing
apparatus intended only for high-quality sound reproduction. 7A and 7B are diagrams showing a
sound reproduction device according to Embodiment 4. FIG. That is, FIG. 7A is a plan view in
which a part of the sound reproduction device is cut away, and FIG. 7B is a G-H cross-sectional
view of the sound reproduction device shown in FIG. In FIGS. 7A and 7B, the sound reproducing
apparatus includes a case 80, a speaker 87 (made of a transparent diaphragm 81 and a
transparent electrode 82), and electromechanical acoustic transducers 83 and 84. In FIG. 7A,
part of the speaker 87 is cut away. The acoustic reproduction apparatus shown in FIG. 7A is
different from the acoustic reproduction apparatus shown in FIG. 4A in that it has no LCD, no
acoustic tube, and a combination of acoustic holes and an electromechanical acoustic transducer.
Is a point having two sets. The other configuration of the sound reproducing apparatus shown in
FIG. 7A is the same as that of the sound reproducing apparatus shown in FIG. 4A, and thus the
description thereof is omitted.
[0071]
In FIG. 7A, since the sound reproducing apparatus has a configuration without an LCD, there is
no need to provide an acoustic tube. That is, if it is a structure provided with LCD, since it is
necessary to arrange | position LCD on the back surface of a speaker, it is necessary to arrange
an electromechanical acoustic transducer on the back side of LCD. In the third embodiment, an
acoustic tube is used to realize such an arrangement, but in the fourth embodiment, this is not
necessary. Further, in the fourth embodiment, since two electromechanical acoustic transducers
are provided, two sound holes 85 and 86 are provided. Note that only one electromechanical
acoustic transducer and one sound hole may be provided.
11-05-2019
22
[0072]
The operation of the sound reproduction apparatus shown in FIG. 7A is the same as the
operation of the sound reproduction apparatus according to the third embodiment. That is, the
sound reproducing apparatus generates a high-pitched sound by the first driving method and
generates a low-pitched sound by the second driving method. Also in the fourth embodiment, as
in the third embodiment, it is preferable that the sound reproducing apparatus includes a signal
processing unit shown in FIG.
[0073]
As described above, according to the fourth embodiment, it is possible to realize an acoustic
reproduction device capable of reproducing a wide band by using two driving methods in
combination. In the fourth embodiment, since the purpose is not to reproduce an image, the
constituent material of the speaker does not have to be transparent. That is, instead of the
transparent diaphragm 81 and the transparent electrode 82, a non-transparent material may be
used. Furthermore, you may use what printed the character, the picture, etc. on the surface of a
speaker. For example, if a speaker is used like a poster, it is possible to realize an audio
reproduction apparatus in which sound is reproduced from the poster.
[0074]
Fifth Embodiment The following describes a sound reproduction device according to a fifth
embodiment. 8A and 8B show a sound reproduction device according to the fifth embodiment.
That is, FIG. 8A is a plan view of the sound reproduction apparatus, and FIG. 8B is an I-J crosssectional view of the sound reproduction apparatus shown in FIG. 8A. In FIG. 8A and FIG. 8B, the
acoustic reproduction device includes the film-like organic EL 120, the piezoelectric film 121, the
case 122, and the electromechanical acoustic transducer 123. In FIG. 8A, a part of the organic EL
120 and the piezoelectric film 121 is cut away. As shown in FIG. 8B, in the fifth embodiment, a
surface panel in which an organic EL 120, which is an example of an image display panel that
displays an image, and a piezoelectric film, which is an example of a sound generation panel that
emits sound, are integrally formed. Is used.
[0075]
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23
The configuration of the sound reproducing apparatus shown in FIG. 8 differs from the second
and third embodiments in that an organic EL 120 as an image display panel and a piezoelectric
film 121 as a sound generation panel are integrally formed. That is, the acoustic reproduction
device shown in FIG. 8 has a configuration in which a piezoelectric film is adhered to the back
surface of the organic EL 40 of the acoustic reproduction device shown in FIG.
[0076]
The operation of the sound reproduction apparatus shown in FIG. 8 is the same as the operation
of the sound reproduction apparatus according to the third embodiment. That is, the surface
panel (organic EL 120 and piezoelectric film 121) of the sound reproduction device according to
the fifth embodiment generates a sound by a driving method acoustically driven by the sound
pressure of the electromechanical acoustic transducer 123, and By applying a signal, a sound is
generated by a driving method in which the piezoelectric film 121 itself is driven. Specifically, the
sound generated from the electromechanical acoustic transducer 123 is transmitted to the space
125 by the sound hole 124. Thus, the piezoelectric film 121 and the organic EL 120 vibrate by
the energy (sound pressure) of the sound radiated from the electromechanical acoustic
transducer 123 to the space 125. On the other hand, when an acoustic signal is applied to the
piezoelectric film 121, since the piezoelectric film 121 and the organic EL 120 are integrated, the
vibration generated in the piezoelectric film 121 causes the organic EL 120 to vibrate.
[0077]
As described above, also in the fifth embodiment, as in the third embodiment, the sound is
emitted by the vibration of the front panel by two types of driving methods. Therefore, also in the
fifth embodiment, as in the third embodiment, by further including the signal processing unit 70
shown in FIG. 6, it is possible to perform sound reproduction with divided bands. That is, the
acoustic reproduction of the bass region is realized by the driving method in which the surface
panel is acoustically driven by the sound pressure of the electromechanical acoustic transducer
54, and the driving method in which the surface panel is driven by the vibration of the
piezoelectric film 121 itself is high. It is possible to realize sound reproduction of the sound
range.
[0078]
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24
According to the fifth embodiment, as in the second embodiment, it is possible to realize a thin
sound reproducing apparatus capable of simultaneously reproducing an image and a sound by
the surface panel. Furthermore, the configuration in which the piezoelectric film is further
provided makes it possible to improve the insufficient output of the high range which is a
concern in the second embodiment. As in the first, second, and third embodiments, the sound
reproduction apparatus according to the fifth embodiment can be typically applied as an
electronic device such as a mobile phone, a game machine, a personal computer, and a television.
[0079]
In the fifth embodiment, the piezoelectric film 121 is adhered to the back surface of the organic
EL 120. However, if a transparent piezoelectric film is used, the piezoelectric film may be
adhered to the surface of the organic EL. . Furthermore, piezoelectric films may be provided on
both sides of the organic EL 120. With this configuration, the sound conversion efficiency is
improved, so that the sound reproducing apparatus can perform reproduction at a higher sound
pressure level.
[0080]
Further, although the piezoelectric film is provided on the entire surface of the organic EL 120 in
FIG. 8, the piezoelectric film may be provided on part of the surface of the organic EL 120 as
shown in FIG. 9. FIG. 9A is a plan view of a sound reproduction device according to a
modification of the fifth embodiment, and FIG. 9B is a K-L cross-sectional view of the sound
reproduction device shown in FIG. 9A. 9A and 9B, the same components as those in FIGS. 8A and
8B are denoted by the same reference numerals.
[0081]
9A and 9B differ from FIGS. 8A and 8B in that piezoelectric elements 130 and 131 are partially
provided to organic EL 120. In this case, as the piezoelectric elements 130 and 131, the
piezoelectric elements shown in FIG. 2 can be used as they are. According to the configuration
shown in FIG. 9A and FIG. 9B, sound is generally emitted with a small vibration area as compared
11-05-2019
25
with a piezoelectric film which has a low radiation efficiency and requires a large area to secure a
sufficient sound pressure level. It can be played back.
[0082]
When two piezoelectric elements 130 and 131 are used, it is possible to perform stereo
reproduction mainly in the high frequency range. Furthermore, by providing two sound holes in
the case 122 and one electromechanical acoustic transducer in each sound hole, it is possible to
perform stereo reproduction also in the bass range.
[0083]
Although the shape of the piezoelectric element is circular in FIGS. 9A and 9B, it may be any
shape such as square or oval. 9A and 9B, although the piezoelectric element is used as a sound
generation panel to be bonded to the organic EL, any sound transducer type sound generation
member such as an electrodynamic type, an electromagnetic type, or an electrostatic type is used
as a sound generation panel It may be used as
[0084]
Sixth Embodiment An electronic device according to a sixth embodiment will be described below.
In the sixth embodiment, an example in which the sound reproduction device according to the
second embodiment is used for a mobile phone which is an example of an electronic device will
be described. FIG. 10 is an external view of a mobile phone which is an example of the electronic
device according to the sixth embodiment. In FIG. 10, a mobile phone 90 includes a case 91, an
antenna 92, and an organic EL 93. Inside the case 91, a signal processing circuit, an
electromechanical acoustic transducer, and the like (not shown) are incorporated. The case 91 is
provided with a sound hole 94 for transmitting the sound emitted from the electromechanical
acoustic transducer. The organic EL 93 is a display panel attached to the case 91, and displays an
image by an electrical signal. In FIG. 10, a part of the organic EL 93 is cut away. The
configuration relating to the case 91, the organic EL 93, the sound hole 94, and the
electromechanical acoustic transducer is the same as the configuration shown in FIG.
[0085]
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26
FIG. 11 is a block circuit diagram of the main part of the mobile phone shown in FIG. In FIG. 11, a
mobile phone 90 includes a received signal processing unit 101, a signal amplification unit 102,
and a sound reproduction device 103. The sound reproducing apparatus 103 has the same
configuration as the sound reproducing apparatus according to the second embodiment shown in
FIG.
[0086]
Hereinafter, the operation of the mobile phone configured as shown in FIGS. 10 and 11 will be
described. The antenna 92 receives a signal transmitted from a wireless base station of a mobile
phone. This signal is an incoming signal indicating an incoming call, a received sound signal
which is the speaking voice of the transmitter, an acoustic signal such as a music signal, or an
image signal such as a moving image or character information. The signal received by the
antenna 92 is input to the received signal processing unit 101 and subjected to signal processing
in the received signal processing unit 101. That is, the reception signal processing unit 101
converts the input signal into an acoustic signal. In addition, when the input signal includes an
image signal, the reception signal processing unit 101 inputs the image signal to the organic EL
93. The acoustic signal is amplified by the signal amplification unit 102, and is input to the
electromechanical acoustic transducer 104 of the acoustic reproduction device 103. Note that
the signal amplification unit 102 can switch the amplification factor according to a user's
instruction (it is assumed to be input to an input unit not shown), and switches the amplification
factor according to the usage pattern of the mobile phone. The acoustic signal output from the
signal amplification unit 102 is reproduced on the surface panel (organic EL 93) vibrated by the
electromechanical acoustic transducer 104. The operation of the sound reproducing apparatus is
the same as that of the second embodiment, and therefore, the description is omitted here to
avoid duplication.
[0087]
In addition, as a form which a user uses a mobile telephone, a form which uses an ear in
proximity to organic EL 93 which radiates a sound, and a form which uses it as a hands free
telephone which talks by separating a user's face from a mobile phone main body There is. If
both the calling party and the called party's mobile phones have a videophone function by
mounting a camera, a conversation using the hands-free phone makes it possible to talk while
looking at the face of the other party displayed on the front panel It is possible to In this case, if
11-05-2019
27
the mobile phone shown in FIG. 10 is used, it is possible to give the user a feeling that the other
party's voice can be heard from the image of the other party's face. Although the front panel
functions as a speaker for loud-speaking in a mode used as a hands-free telephone, the front
panel can also play an alarm sound or melody sound notifying an incoming call or a music signal.
In addition, as an application for simultaneous reproduction of a music signal and an image
signal, it is possible to reproduce a promotion video of a music or to use as a game machine.
[0088]
As described above, according to the sixth embodiment, a mobile phone in which sound is
reproduced from the screen can be realized. In the sixth embodiment, the sound reproduction
device 103 is a device using an organic EL (a sound reproduction device according to the second
embodiment). However, a device using an LCD (a sound reproduction device according to the
first embodiment) ) May be. In addition, the sound reproducing apparatus according to the third
and fifth embodiments may be used. Furthermore, although the mobile phone has been described
as an example in the sixth embodiment, the sound reproducing apparatus according to the first
to third and fifth embodiments is an electronic device such as a television, a personal computer, a
game machine, and a car navigation which is a device having a display screen. Is also easily
applicable. In addition, since the sound reproducing devices according to Embodiments 1 to 3
can be thinned, it is particularly effective to apply the sound reproducing device to a portable
terminal device such as a mobile phone.
[0089]
As described above, according to the present invention, the front panel is configured by the
display device itself, and the display device itself is made to generate sound by acoustically
driving the display device (the LCD and the organic EL described above). It is possible. In
addition, by driving acoustically, it is possible to reproduce the bass range. Further, according to
the present invention, by configuring the surface panel with a speaker such as a piezoelectric
element, it is possible to reproduce a wide band.
[0090]
As described above, the sound reproducing apparatus according to the present invention can be
used for the purpose of improving the sound reproducing function when adding the sound
reproducing function to an apparatus having another function.
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28
[0091]
The figure which shows the sound reproduction apparatus which concerns on Embodiment 1 The
figure which shows the sound reproduction apparatus which shows the sound reproduction
apparatus which concerns on Embodiment 1 The structural cross section of the
electromechanical acoustic transducer 23 shown in FIG. 1A The figure which shows the sound
reproduction apparatus concerning Embodiment 2 The figure which shows the sound
reproduction apparatus which concerns on Embodiment 2 The figure which shows the sound
reproduction apparatus which concerns on Embodiment 3 which shows the sound reproduction
apparatus which concerns on Embodiment 3 The structure sectional view of the
electromechanical acoustic transducer 54 shown to FIG. 4A The block diagram which shows the
function which performs the signal processing in the sound reproducing apparatus concerning
Embodiment 3, The figure which shows the sound reproducing apparatus concerning
Embodiment 4 The figure which shows the sound reproducing apparatus concerning
Embodiment 4 The sound concerning Embodiment 5 The figure which shows a reproducing
apparatus The figure which shows the sound reproduction apparatus which concerns on
Embodiment 5 The figure which shows the modification of the sound reproduction apparatus
which concerns on Embodiment 5 The figure which shows the modification of the sound
reproduction apparatus which concerns on Embodiment 5 One of the electronic devices
pertaining to Sectional view of a conventional display apparatus for reproducing a sound by
providing a speaker in a perspective view the front of a conventional display device having a
block circuit diagram sound reproduction function of the main part of the mobile phone shown in
external view diagram 10 of the mobile phone is
Explanation of sign
[0092]
20, 53 LCD 21 Suspension member 22, 41, 50, 80, 91 Case 23, 42, 54, 83, 84, 104, 123
Electromechanical Acoustic Transducer 40, 93, 120 Organic EL 70 Signal Processing Unit 71
LPF 72 HPF 73 Phase adjustment unit 74 Level adjustment unit
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