JP2009278498A - Flexible stereo speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible stereo speaker for stereo-reproducing a stereo signal while preventing degradation of stereo feeling. <P>SOLUTION: The flexible stereo speaker 1 includes a diaphragm 11, a left channel electrode 12, a right channel electrode 13, a substrate 14, a left channel comb filter 21 for extracting a left channel input signal included in an input stereo signal at a predetermined frequency interval and generating a left channel drive signal, a right channel comb filter 22 having reverse amplitude characteristics to the left channel comb filter 21, extracting a right channel input signal included in the input stereo signal at a predetermined frequency interval, and generating a right channel drive signal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flexible stereo speaker for stereo reproduction of an input stereo signal.

  Conventionally, a flat panel speaker is known (for example, refer to Patent Document 1). In the panel speaker described in Patent Document 1, a right channel drive unit (electrode) is provided on the right side of one diaphragm, and a left channel drive unit (electrode) is provided on the left side. And the panel speaker described in patent document 1 reproduces | regenerates a stereo signal in stereo, when the drive part (electrode) of both right and left ends drives based on the left channel and right channel of a stereo signal, respectively.

In recent years, flat flexible speakers have attracted attention. The flexible speaker is thin and light, so it is convenient to carry and flexible, so its flexibility is high. For example, the flexible speaker can be installed in a place where it is difficult with a conventional speaker, such as affixing to a wall or display in a room, and is excellent in space efficiency. Here, the flexible speaker basically has a mechanism in which a single diaphragm vibrates to generate sound. Therefore, the flexible speaker does not support a stereo signal, and inputs a monaural signal and reproduces it in monaural. Is common.
JP 2004-343481 A

  However, currently distributed audio contents (for example, music programs and music CDs) are mainly two-channel stereo signals (stereo format) including a left channel input signal and a right channel input signal. As described above, since the flexible speaker does not support a stereo signal, there is a problem that the mainstream audio content cannot be reproduced in stereo without impairing the stereo feeling. In addition, as practical use of flexible speakers progresses, there is a strong demand to reproduce stereo signals in stereo without impairing the stereo feeling.

  In addition, in the configuration in which the drive units are provided at both the left and right ends of the diaphragm such as the panel speaker described in Patent Document 1, the vibration wave generated by the left channel input signal and the vibration wave generated by the right channel input signal are mixed. There is a problem that a correlation occurs between the left channel and the right channel, and the stereo feeling is lost.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a flexible stereo speaker that is capable of reproducing a stereo signal in stereo without causing a loss of stereo feeling.

  In order to solve the above-described problem, a flexible stereo speaker according to claim 1 is a flexible stereo speaker that receives a stereo signal including a left channel input signal and a right channel input signal and reproduces the stereo signal in stereo. Type filter, right channel comb filter having an amplitude characteristic opposite to that of the left channel comb filter, a plate-like diaphragm made of an electric field-driven polymer that vibrates according to an electric field, and both surfaces of the diaphragm are opposed to each other A pair of left channel electrodes formed so as to be opposed to each other, a pair of right channel electrodes formed so as to face both surfaces of the diaphragm and adjacent to the left channel electrode, and one side of the diaphragm And a substrate in close contact with the left channel electrode and the right channel electrode on the side.

  In such a configuration, the flexible stereo speaker generates a left channel drive signal by extracting the left channel input signal at a predetermined frequency interval by the left channel comb filter. Here, the left channel comb filter generates a left channel drive signal by extracting the left channel input signal at fine frequency intervals so that human hearing hardly feels the difference from the original left channel input signal. To do.

  The flexible stereo speaker extracts a right channel input signal at a predetermined frequency interval using a right channel comb filter to generate a right channel drive signal. Here, the right channel comb filter generates a right channel drive signal by extracting the right channel input signal at fine frequency intervals so that the human hearing hardly feels the difference from the original right channel input signal. To do. Further, the right channel comb filter has an amplitude characteristic opposite to that of the left channel comb filter, and therefore generates a right channel drive signal with little correlation with the left channel drive signal.

  The flexible stereo speaker generates an electric field by the left channel electrode based on the left channel driving signal generated by the left channel comb filter, and vibrates the diaphragm. The flexible stereo speaker generates an electric field by the right channel electrode based on the right channel drive signal generated by the right channel comb filter, and vibrates the diaphragm. Further, the flexible stereo speaker holds the diaphragm or vibrates the vibration of the diaphragm by the substrate. As a result, the flexible stereo speaker performs stereo reproduction based on the left channel drive signal and the right channel drive signal that have little correlation with each other and that the human auditory sense hardly feels the difference from the original stereo signal. Can do.

  In order to solve the above problem, the flexible stereo speaker according to claim 2 is a flexible stereo speaker that receives a stereo signal including a left channel input signal and a right channel input signal and reproduces the stereo signal in stereo. A channel drive signal generating means, a right channel drive signal generating means, a flat diaphragm made of an electric field driven polymer that vibrates in response to an electric field, and a left channel so as to face each other on both sides of the diaphragm A pair of left channel electrodes formed at positions adjacent to the electrodes, a pair of right channel electrodes formed on both sides of the diaphragm so as to face each other, a left channel electrode on one side of the diaphragm and the right And a substrate that is in close contact with the channel electrode.

  In such a configuration, the flexible stereo speaker subtracts the left channel drive signal by subtracting the right channel input signal that has been reversed in phase by multiplying a preset transfer coefficient from the left channel input signal by the left channel drive signal generation means, Generate. Further, the flexible stereo speaker generates a right channel drive signal by subtracting a left channel input signal, which is obtained by multiplying the transfer coefficient by the transfer coefficient, from the right channel input signal by the right channel drive signal generation means. By using the transfer coefficient in this way, the flexible stereo speaker generates a left channel drive signal and a right channel drive signal that have little correlation with each other.

  Also, the flexible stereo speaker generates an electric field by the left channel electrode based on the left channel drive signal generated by the left channel drive signal generation means, and vibrates the diaphragm. The flexible stereo speaker generates an electric field by the right channel electrode based on the right channel drive signal generated by the right channel drive signal generation means, and vibrates the diaphragm. Further, the flexible stereo speaker holds the diaphragm or vibrates the vibration of the diaphragm by the substrate. Accordingly, the flexible stereo speaker can perform stereo reproduction based on the left channel drive signal and the right channel drive signal that have little correlation with each other.

  In order to solve the above problem, the flexible stereo speaker according to claim 3 is a flexible stereo speaker that receives a stereo signal including a left channel input signal and a right channel input signal and reproduces the stereo signal in stereo. A summing means, a low-pass filter, a flat diaphragm made of an electric field-driven polymer that vibrates according to an electric field, a pair of left channel electrodes formed on both sides of the diaphragm so as to face each other, and vibration A pair of bass channel electrodes formed opposite to each other on both sides of the plate and adjacent to the left channel electrode, and opposite to each other on both sides of the diaphragm and adjacent to the bass channel electrode A pair of right channel electrodes formed at a position, a left channel electrode on one side of the diaphragm, and a bass channel electrode. A plate contacting the right channel electrodes and, was configured with a.

  In such a configuration, the flexible stereo speaker outputs the left channel input signal as the left channel drive signal, the right channel input signal as the right channel drive signal, and the left channel input signal and the right channel input signal by the signal adding means. And add.

  Further, the flexible stereo speaker extracts a low sound region of the left channel input signal and the right channel input signal added by the signal adding means by a low-pass filter to generate a low sound channel drive signal. As a result, the flexible stereo speaker generates a bass drive signal obtained by extracting only a bass region that is difficult to reproduce with vibration having a small amplitude from the stereo signal.

  The flexible stereo speaker generates an electric field by the left channel electrode based on the left channel drive signal output from the signal adding means to vibrate the diaphragm. Then, the flexible stereo speaker generates an electric field by the right channel electrode based on the right channel drive signal output from the signal adding means to vibrate the diaphragm. As a result, the flexible stereo speaker reproduces the sound including the high sound region and the low sound region that easily affect the sound localization (stereo feeling) in the left and right portions of the diaphragm separated from each other.

  The flexible stereo speaker generates an electric field based on the bass channel drive signal generated by the low-pass filter by the bass channel electrode to vibrate the diaphragm. And a flexible stereo speaker hold | maintains a diaphragm or vibrates the vibration of a diaphragm with a board | substrate. As a result, the flexible stereo speaker reproduces low-frequency sounds, which have little influence on the sound localization and difficult to reproduce by vibration with small amplitude, in the central part of the diaphragm in addition to the left and right parts of the diaphragm. .

  4. The flexible stereo speaker according to claim 3, wherein the signal adding means extracts a left channel input signal at a predetermined frequency interval to generate a left channel drive signal, and a left channel comb filter. And a right channel comb filter that extracts a right channel input signal at a predetermined frequency interval and generates a right channel drive signal.

  In this configuration, the flexible stereo speaker generates a left channel drive signal and a right channel drive signal that have little correlation with each other.

  Further, in the flexible stereo speaker according to claim 3, the signal adding means removes the bass channel signal (bass region) from the right channel input signal which has been reversed in phase by a preset transfer coefficient and outputs the signal. First high-pass filter, a signal output from the first high-pass filter is subtracted from the left channel input signal to generate a left channel drive signal, a left channel drive signal generating means for generating a left channel drive signal, A second high-pass filter that outputs a low-frequency channel signal (low-frequency region) removed from the left-channel input signal, and a right-channel drive signal obtained by subtracting the signal output from the second high-pass filter from the right-channel input signal And a right channel drive signal generating means for generating

  In this configuration, the flexible stereo speaker generates a left channel drive signal and a right channel drive signal that have little correlation with each other.

The flexible stereo speaker according to the present invention has the following excellent effects.
According to the first aspect of the present invention, since stereo reproduction is performed based on the left channel drive signal and the right channel drive signal that have little correlation with each other, the separation of the signal sound between the left and right channels becomes clear and the stereo feeling is impaired. It becomes difficult.

  According to the second aspect of the present invention, the interference of the vibration wave due to the left channel drive signal to the right channel and the interference of the vibration wave due to the right channel drive signal to the left channel are reduced, and the stereo feeling is less likely to be impaired.

  According to the third aspect of the present invention, since the sound including the high sound region that easily affects the localization of the sound is reproduced in stereo on the left and right parts of the diaphragm that are separated from each other, the stereo feeling is not easily lost. According to the third aspect of the invention, in addition to the left and right parts of the diaphragm, the center part of the diaphragm is added to the left and right parts of the diaphragm with little influence on the sound localization and difficult to reproduce the stereo feeling. However, since it is played back, it is possible to give the listener a low-pitched tone that was often insufficient with conventional flexible speakers and panel speakers.

  According to the fourth and fifth aspects of the present invention, the left channel drive signal and the right channel drive signal that have little correlation with each other are generated, so that the stereo feeling is less likely to be impaired.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In each embodiment, the same means and the same member are denoted by the same reference numerals, and description thereof is omitted.

(First embodiment)
[Configuration of flexible stereo speakers]
The configuration of the flexible stereo speaker according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic configuration diagram of a flexible stereo speaker according to the first embodiment of the present invention. FIG. 2 is a side view of the flexible stereo speaker of FIG.

  In FIG. 1, the left channel electrode 12b (12) and the right channel electrode 13b (13) formed on the lower surface of the diaphragm 11 are not shown. In FIG. 1, the left channel input signal included in the input stereo signal is shown as Lch, and the right channel input signal of the stereo signal is shown as Rch. In FIG. 2, the control means 20 and the conductive wire 15 are omitted.

  The flexible stereo speaker 1 receives a stereo signal including a left channel input signal and a right channel input signal, and reproduces the stereo signal in stereo. 1 includes a diaphragm 11, a left channel electrode 12a (12), a right channel electrode 13a (13), a substrate 14, four conductors 15a to 15d (15), and control means. 20.

  The vibration plate 11 vibrates according to an electric field, that is, is a flat plate made of an electric field driven polymer having a piezoelectric effect. For example, the diaphragm 11 can be formed of polyvinylidene fluoride (PVDF) or an electric field driven elastomer in which an electrode is formed on an acrylic elastomer, a silicon elastomer, or a urethane elastomer. When the diaphragm 11 is polyvinylidene fluoride, as shown in FIG. 2, the thickness of the diaphragm 11 is, for example, 80 μm.

  The left channel electrode 12 is formed on both surfaces of the diaphragm 11 so as to face each other. Based on the left channel drive signal generated by the left channel comb filter 21 described later, the left channel electrode 12a and the left channel electrode 12b The diaphragm 11 is vibrated by generating an electric field between them. Hereinafter, the left channel electrodes 12a and 12b will be simply referred to as the left channel electrode 12 when not described.

  Here, as the left channel electrode 12, for example, an electrode made of indium tin oxide (ITO), aluminum, or the like is formed on the substantially left half of the diaphragm 11 by sputtering. Here, as shown in FIG. 1, the shape of the left channel electrode 12 is a rounded square, but this shape is not particularly limited, and may be a square, a rectangle, a circle, or an ellipse.

  As shown in FIG. 2, the left channel electrode 12 a is formed on the upper surface 11 a of the diaphragm 11. The left channel electrode 12b is formed on the lower surface 11b of the diaphragm 11 so as to face the left channel electrode 12a. The left channel electrode 12a is connected to the left channel comb filter 21 via a conducting wire 15a, and the left channel electrode 12b is connected to the left channel comb filter 21 via a conducting wire 15b.

  The right channel electrode 13 is formed at a position adjacent to the left channel electrode 12 so as to face each other on both surfaces of the diaphragm 11, and based on a right channel drive signal generated by a right channel comb filter 22 described later. The diaphragm 11 is vibrated by generating an electric field between the right channel electrode 13a and the right channel electrode 13b. Hereinafter, the right channel electrodes 13a and 13b will be simply referred to as the right channel electrode 13 when they are described without distinction.

  Further, the right channel electrode 13 is formed on the substantially right half of the diaphragm 11 with the same shape and material as the left channel electrode 12, for example. Here, as shown in FIG. 2, the right channel electrode 13 a is formed on the upper surface 11 a of the diaphragm 11. The right channel electrode 13b is formed on the lower surface 11b of the diaphragm 11 so as to face the right channel electrode 13a. The right channel electrode 13a is connected to the right channel comb filter 22 via a conducting wire 15c, and the right channel electrode 13b is connected to the right channel comb filter 22 via a conducting wire 15d. In addition, in order to ensure the area of the diaphragm 11 while making it difficult to impair the stereo feeling, the interval between the left channel electrode 12 and the right channel electrode 13 is preferably set to, for example, 5 mm or more and 20 mm or less.

  The substrate 14 is a diaphragm to keep the strength of the flexible stereo speaker 1 or is vibrated by the diaphragm 11, and is, for example, a film of polyethersulfone (PES), polycarbonate, or polyethylene terephthalate (PET). As shown in FIG. 2, the substrate 14 is applied to the left channel electrode 12b and the right channel electrode 13b on one side of the diaphragm 11 (here, the lower surface 11b of the diaphragm 11) with, for example, an adhesive or a double-sided tape. to paste together. When the substrate 14 is made of polyethersulfone, the thickness of the substrate 14 is, for example, 200 μm.

  The conducting wires 15 a and 15 b transmit the left channel drive signal generated by the left channel comb filter 21 to the left channel electrode 12. The conducting wires 15 c and 15 d transmit the right channel drive signal generated by the right channel comb filter 22 to the right channel electrode 13. Hereinafter, when it demonstrates without distinguishing conducting wire 15a-15d, it describes as the conducting wire 15 simply. For example, as the conducting wire 15, a metal wire such as a copper wire or an aluminum wire can be used.

  The control means 20 receives a stereo signal including a left channel input signal and a right channel input signal. As shown in FIG. 1, a left channel comb filter 21, a right channel comb filter 22, Is provided. Here, an example is shown in which the left channel input signal and the right channel input signal are input separately, but the control means 20 separates the left channel input signal and the right channel input signal from the input stereo signal. A circuit may be provided (not shown). Further, the control means 20 may include an amplifier circuit (not shown) that amplifies the left channel drive signal and the right channel drive signal.

  In FIG. 2, the left channel electrode 12 and the right channel electrode 13 are provided on one diaphragm 11, but the diaphragm 11 is not limited to one. For example, two diaphragms 11 having a slightly larger area than the left channel electrode 12 and the right channel electrode 13 are prepared, the left channel electrode 12 is formed on both surfaces of one diaphragm 11, and the right channel is formed on both surfaces of the other diaphragm 11. A channel electrode 13 is formed (not shown). Then, the two diaphragms 11 are bonded to the substrate 14.

  Hereinafter, the left channel comb filter and the right channel comb filter of FIG. 1 will be described with reference to FIG. 3 (see FIG. 1 as appropriate). FIG. 3 is a graph showing the characteristics of the left channel comb filter and the right channel comb filter of FIG. 1, FIG. 3A is a graph showing the characteristics of the left channel comb filter, and FIG. It is a graph which shows the characteristic of a channel comb filter.

  The left channel comb filter 21 extracts a left channel input signal included in an input stereo signal at a predetermined frequency interval (for example, 1/30 octave band interval) to generate a left channel drive signal. . As shown in FIG. 3 (a), the left channel comb filter 21 sets the left channel input signal at a predetermined frequency interval, for example, a reference value of −20 dB, a maximum amplification band of 0 dB, and a band to be suppressed. Signal processing is performed so that the minimum becomes -40 dB. In this way, the left channel comb filter 21 generates a left channel drive signal that hardly perceives a difference from the left channel input signal included in the input stereo signal in human hearing.

For example, when the left channel input signal is l (t), the left channel comb filter 21 is H (z), and the left channel drive signal is L (t), the left channel comb filter 21 is: The left channel drive signal is generated using Equation (1).
L (t) = l (t) × H (z) (1)

  The left channel comb filter 21 outputs the generated left channel drive signal to the left channel electrode 12. Based on the left channel drive signal, an electric field is generated between the left channel electrode 12a and the left channel electrode 12b, and the diaphragm 11 is vibrated by the electric field to generate a sound corresponding to the left channel drive signal. .

  The right channel comb filter 22 has an amplitude characteristic opposite to that of the left channel comb filter 21, and extracts a right channel input signal included in an input stereo signal at a predetermined frequency interval to generate a right channel drive signal. Is to be generated. Here, as shown in FIG. 3B, the right channel comb filter 22 has the same frequency interval as the left channel comb filter 21 and has an amplitude characteristic opposite to that of the left channel comb filter 21. That is, when the amplitude of the left channel comb filter 21 in FIG. 3A becomes a peak, the amplitude of the right channel comb filter 22 in FIG. 3B becomes a valley, and the left channel comb in FIG. When the amplitude of the mold filter 21 is a valley, the amplitude of the right channel comb filter 22 in FIG.

  Further, as shown in FIG. 3B, the right channel comb filter 22 has a portion that has little correlation with the left channel drive signal, specifically, the right channel input signal at a predetermined frequency interval, for example, a reference value. Is set to −20 dB, the signal to be amplified is a maximum of 0 dB, and the suppression band is a minimum of −40 dB. In this way, the right channel drive signal that has little correlation with the right channel comb filter 22 and the left channel drive signal and hardly perceives the difference from the right channel input signal included in the input stereo signal in human hearing. Generate.

For example, when the right channel input signal is r (t), the characteristic of the right channel comb filter 22 is G (z), and the right channel drive signal is R (t), the right channel comb filter 22 The right channel drive signal is generated using Equation (2). G (z) indicates an amplitude characteristic opposite to that of H (z) described above.
R (t) = r (t) × G (z) (2)

  The right channel comb filter 22 outputs the generated right channel drive signal to the right channel electrode 13. Based on the right channel drive signal, an electric field is generated between the right channel electrode 13a and the right channel electrode 13b, and the diaphragm 11 is vibrated by the electric field to generate a sound corresponding to the right channel drive signal. .

  As described above, the flexible stereo speaker 1 uses a comb filter, which is not necessary for a general stereo speaker composed of two speakers. Therefore, the separation of the signal sound between the left and right channels becomes clear, and the stereo sense Is less likely to be damaged.

(Second Embodiment)
[Configuration of flexible stereo speakers]
With reference to FIG. 4, the structure of the flexible stereo speaker which concerns on 2nd Embodiment of this invention is demonstrated. FIG. 4 is a schematic configuration diagram of a flexible stereo speaker according to the second embodiment of the present invention.

  In FIG. 4, the left channel electrode 12b (12) and the right channel electrode 13b (13) formed on the lower surface of the diaphragm 11 are not shown. In FIG. 4, the left channel input signal included in the input stereo signal is shown as Lch, and the right channel input signal of the stereo signal is shown as Rch.

  The flexible stereo speaker 1B of FIG. 4 includes a diaphragm 11, a pair of left channel electrodes 12a (12), a pair of right channel electrodes 13a (13), a substrate 14, and four conductors 15a to 15d ( 15) and the control means 30.

  Here, in the flexible stereo speaker 1B, the diaphragm 11, the left channel electrode 12, the right channel electrode 13, the substrate 14, and the conductive wire 15 are the same as those of the flexible stereo speaker 1 in FIG. To do.

  The control means 30 receives a stereo signal including a left channel input signal and a right channel input signal. As shown in FIG. 4, a left channel drive signal generation means 31 and a right channel drive signal generation means 32 are provided. And comprising.

  The left channel drive signal generation means 31 subtracts a right channel input signal that is reversed in phase by multiplying a preset transfer coefficient from the left channel input signal included in the input stereo signal, Is to be generated.

Here, for example, the transmission coefficient is α (for example, the amplitude is 0.5 times, the time delay is 0.0001 second), the left channel input signal is l (t), the left channel drive signal is L (t), and the right channel. When the input signal is r (t), the left channel drive signal generation means 31 generates a left channel drive signal using the following equation (3).
L (t) = l (t) −α · r (t) (3)
However, in the formula (3), 0 <α <1 is satisfied.

  Further, the left channel drive signal generation means 31 outputs the generated left channel drive signal to the left channel electrode 12. Based on the left channel drive signal, an electric field is generated between the left channel electrode 12a and the left channel electrode 12b, and the diaphragm 11 is vibrated by the electric field to generate a sound corresponding to the left channel drive signal. .

  The right channel drive signal generating means 32 generates a right channel drive signal by subtracting a left channel input signal that has been reversed in phase by multiplying a transfer coefficient from the right channel input signal included in the input stereo signal. is there.

Here, when the transfer coefficient is α, the left channel input signal is l (t), the right channel input signal is r (t), and the right channel drive signal is R (t), the right channel drive signal generating means 32 Generates the right channel drive signal using the following equation (4).
R (t) = r (t) −α · l (t) (4)
However, in the formula (4), 0 <α <1 is satisfied.

  Further, the right channel drive signal generation unit 32 outputs the generated right channel drive signal to the right channel electrode 13. Based on the right channel drive signal, an electric field is generated between the right channel electrode 13a and the right channel electrode 13b, and the diaphragm 11 is vibrated by the electric field to generate a sound corresponding to the right channel drive signal. .

  As described above, the flexible stereo speaker 1B multiplies the input stereo signal by the transfer coefficient, thereby interfering with the right channel of the vibration wave caused by the left channel drive signal and moving to the left channel of the vibration wave caused by the right channel drive signal. Interference is reduced, and the stereo effect is less likely to be impaired.

(Third embodiment)
[Configuration of flexible stereo speakers]
The configuration of the flexible stereo speaker according to the third embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a schematic configuration diagram of a flexible stereo speaker according to the third embodiment of the present invention. FIG. 6 is a side view of the flexible stereo speaker of FIG.

  In FIG. 5, the left channel electrode 12b, the right channel electrode 13b, and the bass channel electrode 16b formed on the lower surface 11b of the diaphragm 11 are not shown. In FIG. 5, the left channel input signal included in the input stereo signal is shown as Lch, and the right channel input signal of the stereo signal is shown as Rch. Moreover, in FIG. 6, the control means 40 and the conducting wire 15 are omitted.

  As shown in FIG. 5, the flexible stereo speaker 1 </ b> C includes a diaphragm 11, a pair of left channel electrodes 12 a (12), a pair of right channel electrodes 13 a (13), a substrate 14, and six conductors. 15 a to 15 f (15), a pair of bass channel electrodes 16 a (16), and a control means 40.

  Here, since the diaphragm 11 and the substrate 14 of the flexible stereo speaker 1C are the same as those of the flexible stereo speaker 1 of FIG.

  For example, the left channel electrode 12 is formed on the left side of the diaphragm 11 so as to open a central portion of the diaphragm 11. Further, the right channel electrode 13 is formed at a position adjacent to a bass channel electrode 16 to be described later, for example, on the right side of the diaphragm 11 so as to leave a central portion of the diaphragm 11.

  The bass channel electrode 16 generates an electric field between the bass channel electrode 16a and the bass channel electrode 16b based on a bass channel drive signal generated by a low-pass filter 42 described later, and vibrates the diaphragm 11. Hereinafter, the bass channel electrodes 16a and 16b will be simply referred to as the bass channel electrode 16 when they are described without being distinguished.

  Further, the bass channel electrode 16 is formed at a position adjacent to both surfaces of the diaphragm 11 and adjacent to the left channel electrode 12, for example, at a central portion of the diaphragm 11. Furthermore, the bass channel electrode 16 is formed with the same shape and material as the left channel electrode 12, for example.

  Here, as shown in FIG. 6, the bass channel electrode 16a is formed at the central portion of the upper surface 11a of the diaphragm 11, that is, between the left channel electrode 12a and the right channel electrode 13a. The right channel electrode 13b is formed at the center portion of the lower surface 11b of the diaphragm 11, that is, between the left channel electrode 12b and the right channel electrode 13b.

  Here, the signal adding means 41, which will be described later, is connected to the left channel electrode 12a via the conducting wire 15a, and is connected to the left channel electrode 12b via the conducting wire 15b. Further, the signal adding means 41 is connected to the right channel electrode 13a via a conducting wire 15e, and is connected to the left channel electrode 12d via a conducting wire 15f. Further, the low-pass filter 42 to be described later is connected to the bass channel electrode 16a via the conducting wire 15c, and is connected to the bass channel electrode 16b via the conducting wire 15d. In addition, in order to make it difficult to impair the sense of stereo, the bass channel electrode 16 preferably has an interval between the left channel electrode 12 and the right channel electrode 13 of, for example, 5 mm or more and 20 mm or less.

  The control means 40 receives a stereo signal including a left channel input signal and a right channel input signal, and includes a signal addition means 41 and a low-pass filter 42 as shown in FIG.

  The signal adding means 41 outputs a left channel input signal included in the input stereo signal as a left channel drive signal, and outputs a right channel input signal included in the input stereo signal as a right channel drive signal. . The signal adding means 41 adds the left channel input signal and the right channel input signal and outputs the result to the low pass filter 42.

  The signal adding means 41 is configured to output the input left channel input signal and the right channel input signal as they are, but includes the left channel comb filter 21 and the right channel comb filter 22 of FIG. (Not shown). In this case, the signal adding means 41 extracts the left channel input signal and the right channel input signal at a predetermined frequency interval, and generates and outputs a left channel drive signal and a left channel drive signal.

  The signal adding means 41 may include the left channel drive signal generating means 31 and the right channel drive signal generating means 32 shown in FIG. 4 (not shown). In this case, the signal addition means 41 removes the low-frequency channel signal from the right channel input signal that has been reversed in phase by multiplying the transfer coefficient, and outputs the result by multiplying the transfer coefficient and reversed phase. And a second high-pass filter that removes the low-frequency channel signal from the left channel input signal and outputs the signal (not shown). The signal adding means 41 generates a left channel drive signal by subtracting the signal output from the first high-pass filter from the left channel input signal by the left channel drive signal generating means, and the right channel drive signal generating means The right channel drive signal is generated by subtracting the signal output from the second high-pass filter from the right channel input signal.

  The low-pass filter 42 extracts a bass region of the left channel input signal and the right channel input signal added by the signal adding unit 41 and generates a bass channel drive signal. Here, as shown in FIG. 7, the low-pass filter 42 extracts a frequency (bass region) equal to or lower than a reference value (for example, 200 Hz) from a signal obtained by adding the left channel input signal and the right channel input signal. A frequency exceeding the value is cut to generate a bass channel drive signal.

  The low pass filter 42 outputs the generated bass channel drive signal to the bass channel electrode 16. Then, based on the bass channel drive signal, an electric field is generated between the bass channel electrode 16a and the bass channel electrode 16b, and the diaphragm 11 vibrates by this electric field, and a sound (bass) corresponding to the bass channel drive signal is generated. Occurs.

  As described above, the flexible stereo speaker 1C is formed so that the left channel electrode 12 and the right channel electrode 13 are spaced apart from each other so that the central portion of the diaphragm 11 is opened. Sound is reproduced in stereo on the left and right parts of the diaphragm 11, and the stereo feeling is less likely to be lost. In addition, since the flexible stereo speaker 1C has the bass channel electrode 16 formed in the central portion of the diaphragm 11, the sound in the bass region, which has little influence on the sound localization and is difficult to reproduce the stereo feeling, can be obtained from the diaphragm. In addition to the left and right parts, the center part of the diaphragm can also be played to give the listener a feeling of bass.

  In FIG. 6, the left channel electrode 12, the bass channel electrode 16, and the right channel electrode 13 are provided on one diaphragm 11, but the diaphragm 11 is not limited to one. For example, three diaphragms 11 having a slightly larger area than the left channel electrode 12, the right channel electrode 13, and the bass channel electrode 16 are prepared, and the left channel electrode 12 is formed on both surfaces of the first diaphragm 11. The bass channel electrode 16 is formed on both surfaces of the diaphragm 11 of the eye, and the right channel electrode 13 is formed on both surfaces of the third diaphragm 11 (not shown). Then, the three diaphragms 11 are bonded to the substrate 14.

(Modification)
In each of the above-described embodiments, the diaphragm 11 has been described as having a uniform thickness. However, the present invention is not limited to this. Hereinafter, a modified example in which the thickness of the diaphragm 11 is not uniform will be described with reference to FIG. FIG. 8 is a side view showing a modification of the flexible stereo speaker according to the first embodiment of the present invention.

In FIG. 8, the control means 20 and the substrate 14 are omitted, and only the conductive wire 15 in contact with the left channel electrode 12a is shown. In FIG. 8, the thickness of the end portion of the diaphragm 11 is shown as T ₁ , the thickness of the central portion of the diaphragm 11 is shown as T ₂ , and the thickness of the concave portion of the diaphragm 11 is shown as T ₃ . Further, in FIG. 8, T ₁ and T ₂ are illustrated with substantially the same thickness, but T ₂ is thicker than T ₁ . That is, in FIG. _{8, T} 1, _{T 2} and _{T 3} satisfy the following formula (5).
T ₂ > T ₁ > T ₃ Formula (5)

As shown in FIG. 8, so that the vibration plate 11 at an intermediate position of two conductors 15 in contact with the left channel electrode 12a (the position of the T ₃₎ is thinnest, forming a recess in the upper surface 11a of the diaphragm 11 . The vibration plate 11 is formed thick central portion is between the left channel electrode 12a and the right channel electrode 13a (the position of T _2). And the left channel electrode 12a is formed in this recessed part, and the two conducting wires 15 are line-contacted substantially parallel to both the left and right sides of the left channel electrode 12a. Here, the right channel electrode 13a is formed in the same manner as the left channel electrode 12a. By forming the diaphragm 11 in this way and performing the same signal processing as in the first embodiment, the flexible stereo speaker according to the present invention can generate the vibration wave of the left channel electrode 12 and the vibration wave of the right channel electrode 13. Interference can be reduced.

  Furthermore, by providing the diaphragm 11 with a recess, the flexible stereo speaker according to the present invention can cause the diaphragm 11 to vibrate equally while keeping the electric field strength in the diaphragm 11 constant. This is particularly effective when an elastomer having a lower conductivity than that of metal is used as the left channel electrode 12 and the right channel electrode 13.

In FIG. 8, the _{T 2} greater than _{T 1,} and, although the _{T 1} was thicker than _{T 3,} the diaphragm 11, as the same thickness and _{T 1} and _{T 3,} the central portion of the diaphragm 11 ( T ₂ of the position) only may be thicker than _{T 1} and _{T 3} (not shown). Also in this case, the flexible stereo speaker according to the present invention can reduce interference between the vibration wave of the left channel electrode 12 and the vibration wave of the right channel electrode 13 as described above.

1 is a schematic configuration diagram of a flexible stereo speaker according to a first embodiment of the present invention. It is a side view of the flexible stereo speaker of FIG. 2 is a graph showing characteristics of the left channel comb filter and the right channel comb filter of FIG. 1, (a) is a graph showing characteristics of the left channel comb filter, and (b) is a right channel comb filter. It is a graph which shows the characteristic. It is a schematic block diagram of the flexible stereo speaker which concerns on 2nd Embodiment of this invention. It is a schematic block diagram of the flexible stereo speaker which concerns on 3rd Embodiment of this invention. It is a side view of the flexible stereo speaker of FIG. It is a graph which shows the characteristic of the low pass filter of FIG. It is a side view which shows the modification of the flexible stereo speaker which concerns on 1st Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flexible stereo speaker 1B Flexible stereo speaker 1C Flexible stereo speaker 11 Diaphragm 12 Left channel electrode 12a Left channel electrode 12b Left channel electrode 13 Right channel electrode 13a Right channel electrode 13b Right channel electrode 14 Substrate 15 Conductor 15a Conductor 15b Conductor 15c Conductor 15d Conductor 15e Conductor 15f Conductor 16 Bass channel electrode 16a Bass channel electrode 16b Bass channel electrode 20 Control means 21 Left channel comb filter 22 Right channel comb filter 30 Control means 31 Left channel drive signal generation means 32 Right channel drive signal generation means 40 Control means 41 Signal addition means 42 Low-pass filter

Claims (5)

In a flexible stereo speaker that receives a stereo signal including a left channel input signal and a right channel input signal and reproduces the stereo signal in stereo,
A left channel comb filter that extracts the left channel input signal at predetermined frequency intervals to generate a left channel drive signal;
A right channel comb filter having an amplitude characteristic opposite to that of the left channel comb filter, and extracting the right channel input signal at a predetermined frequency interval to generate a right channel drive signal;
A flat diaphragm made of an electric field-driven polymer that vibrates in response to an electric field;
A pair of left channel electrodes that are formed on both surfaces of the diaphragm so as to oppose each other and generate the electric field based on a left channel drive signal generated by the left channel comb filter; ,
The electric field is generated based on a right channel driving signal generated by the right channel comb filter so as to be opposed to each other on both surfaces of the diaphragm and adjacent to the left channel electrode. A pair of right channel electrodes for vibrating the diaphragm;
A substrate that is in close contact with the left channel electrode and the right channel electrode on one side of the diaphragm, holds the diaphragm, or vibrates vibration of the diaphragm;
A flexible stereo speaker. In a flexible stereo speaker that receives a stereo signal including a left channel input signal and a right channel input signal and reproduces the stereo signal in stereo,
Left channel drive signal generating means for generating a left channel drive signal by subtracting the right channel input signal that has been reversed in phase by multiplying a preset transfer coefficient from the left channel input signal;
A right channel drive signal generating means for generating a right channel drive signal by subtracting a left channel input signal that has been reversed in phase by multiplying the transfer coefficient from the right channel input signal;
A flat diaphragm made of an electric field-driven polymer that vibrates in response to an electric field;
A pair of left channel electrodes that are formed on both surfaces of the diaphragm so as to face each other and generate the electric field and vibrate the diaphragm based on the left channel drive signal generated by the left channel drive signal generation means When,
The electric field is generated based on a right channel drive signal generated by the right channel drive signal generation means, which is formed at a position adjacent to the left channel electrode so as to face each other on both surfaces of the diaphragm. A pair of right channel electrodes for vibrating the diaphragm;
A substrate that is in close contact with the left channel electrode and the right channel electrode on one side of the diaphragm, holds the diaphragm, or vibrates vibration of the diaphragm;
A flexible stereo speaker. In a flexible stereo speaker that receives a stereo signal including a left channel input signal and a right channel input signal and reproduces the stereo signal in stereo,
A signal adding means for outputting the left channel input signal as a left channel drive signal, outputting the right channel input signal as a right channel drive signal, and adding the left channel input signal and the right channel input signal;
A low pass filter for extracting a bass region of the left channel input signal and the right channel input signal added by the signal adding means to generate a bass channel drive signal;
A flat diaphragm made of an electric field-driven polymer that vibrates in response to an electric field;
A pair of left channel electrodes that are formed on both surfaces of the diaphragm so as to oppose each other and generate the electric field based on a left channel drive signal output by the signal adding means, and vibrate the diaphragm;
The electric field is generated based on a bass channel driving signal generated by the low-pass filter so as to be opposed to each other on both surfaces of the diaphragm and adjacent to the left channel electrode. A pair of bass channel electrodes to vibrate;
The diaphragm is formed on a position adjacent to the bass channel electrode so as to be opposed to each other on both surfaces of the diaphragm and generates the electric field based on a right channel drive signal output from the signal adding means. A pair of right channel electrodes that vibrate
A substrate that is in close contact with the left channel electrode, the bass channel electrode, and the right channel electrode on one side of the diaphragm, holds the diaphragm, or vibrates the vibration of the diaphragm;
A flexible stereo speaker. The signal adding means includes
A left channel comb filter that extracts the left channel input signal at predetermined frequency intervals to generate a left channel drive signal;
A right channel comb filter having an amplitude characteristic opposite to that of the left channel comb filter, and extracting the right channel input signal at a predetermined frequency interval to generate a right channel drive signal;
The flexible stereo speaker according to claim 3, further comprising: The signal adding means includes
A first high-pass filter that removes a low-frequency channel signal from the right-channel input signal that has been reversed in phase by a preset transfer coefficient, and outputs the low-frequency channel signal;
Left channel drive signal generating means for generating the left channel drive signal by subtracting the signal output from the first high-pass filter from the left channel input signal;
A second high-pass filter that removes and outputs the signal for the bass channel from the left channel input signal that has been reversed in phase by the transfer coefficient;
Right channel drive signal generation means for generating the right channel drive signal by subtracting the signal output from the second high-pass filter from the right channel input signal;
The flexible stereo speaker according to claim 3, further comprising:

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