JP2012029097A - Sound output device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a new sound reproduction system in a parametric speaker.SOLUTION: A sound output device 100 has a parametric speaker 10 and a controller. The parametric speaker 10 generates an ultrasonic wave depending on sound information to form acoustic fields 1, 2, and 3 where a sound is reproduced by demodulation of the ultrasonic wave. The controller controls the parametric speaker 10 so that the acoustic fields 1, 2, and 3 are formed in a plurality of regions and that a sound different from each other is reproduced in each of the acoustic fields 1, 2, and 3.

Description

  The present invention relates to an audio output device.

  A parametric speaker reproduces sound in the audible range by demodulating a modulated audio signal after oscillation. A parametric speaker is also called a directional speaker or the like, and is characterized by high directivity of output sound. For this reason, it is possible to selectively form a sound field in a specific region by using a parametric speaker.

  Patent Document 1 describes a parametric speaker that can change the reach of sound waves.

JP 2006-245731 A

  If a new sound reproduction method of a parametric speaker is realized, a new acoustic effect and a new usage method of the parametric speaker can be created.

  An object of the present invention is to provide an audio output device capable of realizing a new audio reproduction method in a parametric speaker.

According to the present invention, a parametric speaker that oscillates an ultrasonic wave according to audio information and forms a sound field in which audio is reproduced by demodulating the ultrasonic wave;
A control unit that controls the parametric speaker so that the sound fields are formed in a plurality of regions, and different sounds are reproduced in the sound fields;
An audio output device is provided.

  According to the present invention, a new audio reproduction method can be realized in a parametric speaker.

It is a schematic diagram for demonstrating the audio | voice output apparatus which concerns on 1st Embodiment. It is a block diagram of the audio | voice output apparatus which concerns on 1st Embodiment. It is a schematic diagram of the oscillation apparatus with which the audio | voice output apparatus which concerns on 1st Embodiment is provided. It is sectional drawing which shows the layer structure of a vibrator | oscillator. It is a schematic diagram which shows the example of a structure of audio | voice information. It is a schematic diagram for demonstrating the audio | voice reproduction | regeneration system by the audio | voice output apparatus which concerns on 2nd Embodiment. It is a schematic diagram for demonstrating the audio | voice reproduction | regeneration system by the audio | voice output apparatus which concerns on 3rd Embodiment. It is a schematic diagram for demonstrating the audio | voice output apparatus which concerns on 4th Embodiment. It is a block diagram of the audio | voice output apparatus which concerns on 5th Embodiment. It is a disassembled perspective view which shows the structure of the MEMS actuator used as a vibrator | oscillator of the oscillation apparatus with which the audio | voice output apparatus which concerns on 6th Embodiment is provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

[First Embodiment]
FIG. 1 is a schematic diagram for explaining an audio output device 100 according to the first embodiment, and FIG. 2 is a block diagram of the audio output device 100 according to the first embodiment.

  The audio output device 100 according to the first embodiment includes a parametric speaker 10 and a control unit 6. The parametric speaker 10 oscillates an ultrasonic wave according to audio information, and forms sound fields 1, 2, and 3 in which audio is reproduced by demodulating the ultrasonic wave. The control unit 6 controls the parametric speaker 10 so that sound fields 1, 2, and 3 are formed in a plurality of regions, and different sounds are reproduced in the sound fields 1, 2, and 3, respectively. The audio output device 100 is, for example, an AV device such as a television, a large-scale audiovisual facility such as a theater or a movie theater, other electronic devices (for example, a portable terminal device such as a mobile phone or a PDA (Personal Digital Assistant), a lap A top-type personal computer, a small game machine, and the like. Details will be described below.

  As shown in FIG. 1, the parametric speaker 10 includes, for example, a plurality of oscillation devices 11 that oscillate ultrasonic waves in an array. These oscillation devices 11 are arranged in a matrix, for example. By controlling the phase of the ultrasonic wave output from each oscillation device 11 of the parametric speaker 10 by the control unit 6 (FIG. 2), the sound fields 1, 2, and 3 where the sound is reproduced are formed in specific regions, respectively. be able to. That is, the sound fields 1, 2, and 3 can be formed in a specific direction when viewed from the parametric speaker 10, and can be formed at a predetermined distance from the parametric speaker 10.

  In the case of this embodiment, for example, three sound fields 1, 2, and 3 are formed in different regions in parallel in time series. For this reason, any one of the plurality of oscillation devices 11 of the parametric speaker 10 is used for forming the sound field 1, the other plurality of oscillation devices 11 are used for forming the sound field 2, and The other plurality of oscillation devices 11 are used to form the sound field 3. That is, the parametric speaker 10 includes a plurality of oscillation devices 11 for forming the sound field 1, a plurality of oscillation devices 11 for forming the sound field 2, and a plurality of oscillation devices 11 for forming the sound field 3. Have. Any one of the oscillation devices 11 may be shared for forming a plurality of sound fields (two or more of the sound fields 1, 2, and 3).

  The positions for forming the sound fields 1, 2, and 3 are arbitrary. For example, in FIG. 1, when the position of the user 9 with respect to the audio output device 100 is predetermined, the right side of the user 9 (sound field 1), above the user 9 (sound field 2), and the user 9. The example which forms the left side (sound field 3) is shown. The user 9 can hear the sound generated in each of the sound fields 1, 2, and 3. As described above, since the sound fields 1, 2, and 3 can be formed in a region in a specific direction and a predetermined distance when viewed from the parametric speaker 10, each sound field 1, 2, and 3 functions like a point sound source, for example. .

  The control unit 6 controls the parametric speaker 10 according to audio information input from the outside, for example.

Here, as shown in FIG. 5, the audio information 60 includes, for each sound field 1, 2, 3, reproduction sound information indicating the sound to be reproduced, and a region where the sound fields 1, 2, 3 are formed Sound field forming area information indicating the position.
The first sound information 61 for the sound field 1 includes first reproduction sound information 61a indicating sound reproduced in the sound field 1, and first sound field formation area information indicating the position of the area where the sound field 1 is formed. 61b. Similarly, the second sound information 62 for the sound field 2 includes the second reproduction sound information 62a indicating the sound reproduced in the sound field 2, and the second sound field indicating the position of the region where the sound field 2 is formed. Formation region information 62b. Similarly, the third sound information 63 for the sound field 3 includes the third reproduction sound information 63a indicating the sound reproduced in the sound field 3, and the third sound field indicating the position of the region where the sound field 3 is formed. Formation region information 63b.

  FIG. 3 is a schematic diagram of the oscillation device 11 included in the audio output device 100 according to the first embodiment.

  The oscillation device 11 includes, for example, a sheet-like vibration member 30, a vibrator 20, a support member 40, and a signal generation unit 54. The vibrator 20 is a piezoelectric vibrator, for example, and is attached to one surface of the vibration member 30. The support member 40 supports the edge of the vibration member 30. The support member 40 is fixed to, for example, a circuit board (not shown) or a housing of the audio output device 100. The signal generation unit 54 and the control unit 6 constitute an oscillation circuit (input unit) that oscillates the transducer 20 by inputting an oscillation signal to the transducer 20 and oscillates a sound wave from the transducer 20 and the vibrating member 30. ing.

  The vibration member 30 vibrates due to vibration generated from the vibrator 20, and oscillates a sound wave having a frequency of 20 kHz or more, for example. The vibrator 20 also oscillates, for example, a sound wave having a frequency of 20 kHz or more when vibrated. The vibrating member 30 adjusts the basic resonance frequency of the vibrator 20. The fundamental resonance frequency of the mechanical vibrator depends on the load weight and compliance. Since the compliance is the mechanical rigidity of the vibrator, the basic resonance frequency of the vibrator 20 can be controlled by controlling the rigidity of the vibration member 30. The thickness of the vibration member 30 is preferably 5 μm or more and 500 μm or less. In addition, the vibration member 30 preferably has a longitudinal elastic modulus, which is an index indicating rigidity, of 1 Gpa or more and 500 GPa or less. When the rigidity of the vibration member 30 is too low or too high, there is a possibility that the characteristics and reliability of the mechanical vibrator are impaired. The material constituting the vibration member 30 is not particularly limited as long as it is a material having a high elastic modulus with respect to the vibrator 20 that is a brittle material, such as metal or resin, but phosphor bronze or the like from the viewpoint of workability and cost. Stainless steel or the like is preferable.

  In the present embodiment, the planar shape of the vibrator 20 is a circle. However, the planar shape of the vibrator 20 is not limited to a circle. The entire surface of the vibrator 20 facing the vibration member 30 is fixed to the vibration member 30 with an adhesive. Thereby, the entire surface of one surface of the vibrator 20 is restrained by the vibration member 30.

  The signal generation unit 54 generates an electric signal input to the vibrator 20, that is, a modulation signal in a parametric speaker. The transport wave of the modulation signal is, for example, an ultrasonic wave having a frequency of 20 kHz or higher, and specifically, an ultrasonic wave having a frequency of 100 kHz, for example. The control unit 6 controls the signal generation unit 54 in accordance with an audio signal input from the outside.

  FIG. 4 is a cross-sectional view showing the layer structure of the vibrator 20 in the thickness direction. The vibrator 20 includes a piezoelectric body 22, an upper surface electrode 24, and a lower surface electrode 26.

The piezoelectric body 22 is polarized in the thickness direction. The material constituting the piezoelectric body 22 may be either an inorganic material or an organic material as long as it has a piezoelectric effect. However, a material having high electromechanical conversion efficiency such as zirconate titanate (PZT) or barium titanate (BaTiO ₃ ) is preferable. The thickness h1 of the piezoelectric body 22 is, for example, not less than 10 μm and not more than 1 mm. When the thickness h <b> 1 is less than 10 μm, there is a possibility that the vibrator 20 is damaged when the oscillation device 11 is manufactured. On the other hand, if the thickness h1 is more than 1 mm, the electromechanical conversion efficiency becomes too low, and there is a possibility that a sufficiently large vibration cannot be obtained. The reason is that as the thickness of the vibrator 20 increases, the electric field strength in the piezoelectric vibrator decreases in inverse proportion.

  Although the material which comprises the upper surface electrode 24 and the lower surface electrode 26 is not specifically limited, For example, silver and silver / palladium can be used. Since silver is used as a general-purpose electrode material with low resistance, it has advantages in manufacturing process and cost. Since silver / palladium is a low-resistance material excellent in oxidation resistance, there is an advantage from the viewpoint of reliability. The thickness h2 of the upper surface electrode 24 and the lower surface electrode 26 is not particularly limited, but the thickness h2 is preferably 1 μm or more and 50 μm or less. When the thickness h2 is less than 1 μm, it is difficult to uniformly mold the upper surface electrode 24 and the lower surface electrode 26, and as a result, the electromechanical conversion efficiency may be reduced. Moreover, when the film thickness of the upper surface electrode 24 and the lower surface electrode 26 exceeds 100 μm, the upper surface electrode 24 and the lower surface electrode 26 serve as constraining surfaces with respect to the piezoelectric body 22, and there is a possibility that energy conversion efficiency is reduced.

  The vibrator 20 can have an outer diameter = φ18 mm, an inner diameter = φ12 mm, and a thickness = 100 μm. Further, as the upper surface electrode 24 and the lower surface electrode 26, for example, a silver / palladium alloy having a thickness of 8 μm (weight ratio is, for example, 7: 3) can be used. The vibrating member 30 may be made of phosphor bronze having an outer diameter = φ20 mm and a thickness = 50 μm (0.3 mm). The support member 40 functions as a case of the oscillation device 11 and is formed in a cylindrical shape (for example, a cylindrical shape) with an outer diameter = φ22 mm and an inner diameter = φ20 mm, for example.

  The parametric speaker 10 emits ultrasonic waves (transport waves) subjected to AM modulation, DSB modulation, SSB modulation, and FM modulation from each of a plurality of oscillation sources in the air, and nonlinear characteristics when the ultrasonic waves propagate in the air. Thus, an audible sound appears. Non-linear here means that the flow changes from laminar flow to turbulent flow when the Reynolds number indicated by the ratio between the inertial action and the viscous action of the flow increases. Since the sound wave is slightly disturbed in the fluid, the sound wave propagates nonlinearly. In particular, in the ultrasonic frequency band, the nonlinearity of sound waves can be easily observed. And when an ultrasonic wave is radiated in the air, harmonics accompanying the nonlinearity of the sound wave are remarkably generated. The sound wave is a dense state where the density of the molecular density is generated in the air. When it takes time for air molecules to recover from compression, air that cannot be recovered after compression collides with air molecules that continuously propagate, and a shock wave is generated. An audible sound is generated by the shock wave, that is, the audible sound is reproduced (demodulated). The parametric speaker 10 has an advantage of high sound directivity.

Next, a series of operations will be described.
When the audio information 60 (FIG. 5) is input to the control unit 6, the signal generation unit 54 is controlled, and the signal generation unit 54 generates a modulation signal input to the transducer 20. Here, the control unit 6 controls the signal generation unit 54 based on the first reproduction sound information 61 a of the first audio information 61, so that the signal generation unit 54 generates a modulation signal for audio reproduction in the sound field 1. . Similarly, the control unit 6 controls the signal generation unit 54 based on the second reproduction sound information 62 a of the second audio information 62, so that the signal generation unit 54 generates a modulation signal for audio reproduction in the sound field 2. The control unit 6 controls the signal generation unit 54 based on the third reproduction sound information 63a of the third audio information 63, so that the signal generation unit 54 generates a modulation signal for sound reproduction in the sound field 3. Then, the signal generation unit 54 outputs a modulation signal for sound reproduction in the sound field 1 to the oscillation device 11 for forming the sound field 1, and outputs a modulation signal for sound reproduction in the sound field 2 in the sound field 2. It outputs to the oscillating device 11 for forming, and outputs a modulation signal for sound reproduction in the sound field 3 to the oscillating device 11 for forming the sound field 3. Thereby, the vibrator 20 of each oscillation device 11 vibrates according to the modulation signal corresponding to the sound to be reproduced in the corresponding sound field (any one of the sound fields 1 to 3).
At the same time, the control unit 6 performs phase control of the oscillator 11 for forming the sound field 1 according to the first sound field forming region information 61 b of the first sound information 61. Thereby, the sound field 1 can be formed in a desired region (position). Similarly, the control unit 6 controls the phase of the oscillation device 11 for forming the sound field 2 in accordance with the second sound field forming region information 62b of the second sound information 62, so that the sound is generated in a desired region (position). The field 2 can be formed, and the control unit 6 controls the phase of the oscillation device 11 for forming the sound field 3 in accordance with the third sound field forming region information 63b of the third sound information 63, so that a desired region (position ) Can form a sound field 3.

Thus, in this embodiment, for example, the parametric speaker 10 includes a plurality of oscillation devices 11 that oscillate ultrasonic waves in an array, and each oscillation device 11 has a corresponding sound field 1, 2, 3, respectively. The sound fields 1, 2, and 3 are respectively formed in a plurality of regions in parallel in time series.
For example, by forming sound fields 1, 2, and 3 in a plurality of areas around the user 9, it is possible to realize an audio reproduction method that can produce an unprecedented high sound effect. it can. For example, in an AV device such as a TV, or in a theater or movie theater, the positions of the sound fields 1, 2, and 3 and the sound reproduced in the sound fields 1, 2, and 3 can be linked to the video . By doing so, it is possible to further enhance the sense of reality. Also, three-dimensional sound can be realized by forming sound fields on the left, right, up, down, front and back of the user 9, respectively.

  According to the first embodiment as described above, a new audio reproduction method can be realized in the parametric speaker.

[Second Embodiment]
FIG. 6 is a schematic diagram for explaining an audio reproduction method by the audio output device according to the second embodiment. In the first embodiment, the example in which the sound fields 1, 2, and 3 are respectively formed in a plurality of regions in parallel in time series has been described. However, in the second embodiment, the sound fields 1, 2, and 3 are formed. A plurality of regions in which 3 is formed are sequentially switched over time. That is, as shown in FIG. 6, for example, first, the sound field 1 is formed on the right side of the user 9 (FIG. 6A), and then the sound field 2 is formed above the user 9 (FIG. 6). (B)) After that, the sound field 3 can be formed on the left side of the user 9 (FIG. 6C). The other points of the second embodiment are the same as those of the first embodiment.

  According to the second embodiment described above, the same effects as those of the first embodiment can be obtained. In addition, the sound fields 1, 2, and 3 are switched over time, so that a sound effect as if the sound field is moving can be realized, and it is possible to bring out a sense of reality.

[Third Embodiment]
FIG. 7 is a schematic diagram for explaining an audio reproduction method by the audio output device according to the third embodiment. In the first and second embodiments, the example in which the positions of the sound fields 1, 2, and 3 are fixed has been described. On the other hand, in this embodiment, as shown in FIG. 7, the region (position) where one sound field (for example, sound field 1) is formed is changed with time. For this purpose, in the third embodiment, the region (position) indicated by the sound field formation region information (for example, the first sound field formation region information 61b) of the audio information 60 changes with time. With the change of the region indicated by the sound field formation region information, the control unit 6 performs phase control of the ultrasonic wave output from each oscillation device 11, whereby the sound field can be moved with time. The third embodiment is the same as the first or second embodiment in other points. Although the method of moving the sound field is arbitrary, FIG. 7 shows an example in which the sound field 1 is moved around the user 9, for example.

  According to the third embodiment described above, the same effects as those of the first or second embodiment can be obtained. Moreover, by changing the region (position) in which the sound field is formed over time, it is possible to realize a sound effect as if the sound field is moving smoothly, thereby creating a sense of reality. .

[Fourth Embodiment]
FIG. 8 is a schematic diagram for explaining an audio output device according to the fourth embodiment. In the third embodiment, a region (position) where a sound field is formed is obtained by performing phase control of each oscillation device 11 of a parametric speaker 10 (FIG. 1) having a plurality of oscillation devices 11 in an array. The example to change was demonstrated. On the other hand, in the fourth embodiment, the sound field forming region is moved by changing the output direction of the sound wave from the oscillation device 11 by the actuator 12.

  In the case of this embodiment, instead of the parametric speaker 10 having a plurality of oscillation devices 11 in an array, a parametric speaker 10 composed of a single oscillation device 11 and a plurality of actuators 12 for changing the direction of the parametric speaker 10. And a support portion 13 to which these actuators 12 are fixed.

  The support unit 13 is directly or indirectly fixed to the housing of the audio output device. The support part 13 is formed in a flat plate shape, for example.

  The actuator 12 is a piezoelectric element, for example, and expands and contracts by controlling the applied voltage. One end of each actuator 12 is fixed to the support portion 13, and the other end is fixed to, for example, the support member 40 of the oscillation device 11. For example, as shown in FIG. 8, each actuator 12 is provided so as to stand vertically from one surface of the support portion 13.

  The number of actuators 12 can be two or three. When the three actuators 12 are provided, the degree of freedom in adjusting the orientation of the oscillation device 11 is increased. FIG. 8 shows an example in which two actuators 12 are provided.

  In the normal state, the output direction of the ultrasonic wave from the oscillation device 11 is opposite to the support portion 13 (that is, in the normal state, the vibration member 30 and the support portion 13 of the oscillation device 11 are connected to each other). They are parallel to each other) (FIG. 8 (a)).

  Further, by contracting any one of the actuators 12 (or extending any one of the actuators 12), the angle of the oscillation device 11 with respect to the support portion 13 is changed, and the output direction of the ultrasonic wave from the oscillation device 11 is changed. (That is, the vibrating member 30 can be inclined with respect to the support portion 13) (FIGS. 8B and 8C).

  In other respects, the fourth embodiment is the same as the third embodiment.

According to the fourth embodiment, the same effect as in the third embodiment can be obtained.
In the case of the fourth embodiment, the range of formation of the sound field 2 is moved by changing the output direction of the sound wave from the oscillation device 11 by the actuator 12, so that the parametric speaker 10 has a plurality of oscillation devices 11 arranged in an array. For example, a single oscillation device 11 may be provided.

[Fifth Embodiment]
FIG. 9 is a block diagram of an audio output device 100 according to the fifth embodiment. In each of the above embodiments, the example in which the position of the user 9 with respect to the sound reproduction device is determined in advance has been described. However, in the fifth embodiment, the sound output device 100 detects the position of the user 9 and An example in which the sound fields 1, 2, and 3 are formed at positions (areas) corresponding to the detected positions will be described.

  As shown in FIG. 9, in the present embodiment, the audio output device 100 includes a monitor 5 and an ultrasonic sensor 4 for detecting the position of the user 9.

The monitor 5 includes, for example, an imaging unit (camera) 7 that images the user 9, and a determination unit 8 that determines the direction of the user 9 viewed from the audio output device 100 based on the imaging result of the imaging unit 7. ,have.
The imaging unit 7 acquires images continuously (or intermittently) in real time, and supplies the acquired image data to the determination unit 8.
The determination unit 8 determines the direction of the user 9 by image recognition. The determination unit 8 extracts a human face from the image, and determines the direction of the extracted face as the direction of the user. The determination unit 8 notifies the control unit 6 of the determination result.

  In the present embodiment, at least one of the plurality of oscillation devices 11 of the parametric speaker 10 functions as the ultrasonic sensor 4. The oscillation device 11 other than the ultrasonic sensor 4 is used for sound reproduction, whereas the ultrasonic sensor 4 is used as a sonar. That is, the ultrasonic sensor 4 oscillates an ultrasonic wave toward the user 9 and detects the ultrasonic wave that has rebounded from the user 9. Based on the time from when the ultrasonic sensor 4 oscillates the ultrasonic wave from the ultrasonic sensor 4 until the ultrasonic sensor 4 detects the ultrasonic wave bounced by the ultrasonic sensor 4, the control unit 6 transmits the ultrasonic wave from the audio sensor 100 to the user 9. The distance to is calculated. In addition, you may make it perform the oscillation and detection of an ultrasonic wave with the single ultrasonic sensor 4, and provide the ultrasonic sensor 4 which detects an ultrasonic wave separately from the ultrasonic sensor 4 which oscillates an ultrasonic wave. May be.

  The control unit 6 determines the position of the user 9 according to the calculated distance and the direction determined by the determination unit 8 so that a sound field is formed in a predetermined region with the position as a reference. The directivity of the sound wave output from the parametric speaker 10 is controlled. As a result, a sound field can be formed in a predetermined area based on the position of the user 9. For example, the region specified by the sound field forming region information (first to third sound field forming region information 61b to 63b in FIG. 5) may be corrected according to the position of the detected user 9.

  Note that the monitor 5 may include a plurality of (for example, two) imaging units 7. In this case, the orientation of the user 9 can be determined with higher accuracy by determining the orientation of the user 9 based on the imaging results of the two imaging units 7.

[Sixth Embodiment]
The oscillation device 11 of the audio output device according to the present embodiment has a MEMS (Micro Electro Mechanical Systems) actuator 70 shown in FIG. In other respects, the audio output device according to the present embodiment is configured similarly to the audio output devices according to the first to fifth embodiments.

  In the example shown in FIG. 10, the driving method of the MEMS actuator 70 is a piezoelectric method, and has a structure in which a piezoelectric thin film layer 72 is sandwiched between an upper movable electrode layer 74 and a lower movable electrode layer 76. The MEMS actuator 70 operates when a signal is input from the signal generation unit 54 to the upper movable electrode layer 74 and the lower movable electrode layer 76. For example, an aerosol deposition method is used for manufacturing the MEMS actuator 70, but the method is not limited to this method. However, it is preferable to use the aerosol deposition method because the piezoelectric thin film layer 72, the upper movable electrode layer 74, and the lower movable electrode layer 76 can be formed on curved surfaces. The driving method of the MEMS actuator 70 may be an electrostatic method, an electromagnetic method, or a heat conduction method.

  As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.

  In the first embodiment described above, the example in which the sound field forming area is controlled according to the sound field forming area information attached to the sound information has been described. The formation area may be analyzed, and a sound field may be formed in the analyzed area. In this case, stereo sound information is input as sound information, and the control unit 6 analyzes a plurality of regions in which a sound field is to be formed based on the stereo sound information. For example, by analyzing the sound pressure level indicated by stereo sound information, the sound to be heard to the right ear and the sound to be heard to the left ear are individually analyzed, and the vicinity of the right ear and the vicinity of the left ear are analyzed. , The regions forming the sound field are determined. Then, a sound field where the right ear sound is reproduced and a sound field where the left ear sound is reproduced are formed in each of the determined areas.

1, 2, 3 Sound field 4 Ultrasonic sensor 5 Monitor 6 Control unit 7 Imaging unit 8 Determination unit 9 User 10 Parametric speaker 11 Oscillator 12 Actuator 13 Support unit 20 Vibrator 22 Piezoelectric body 24 Upper surface electrode 26 Lower surface electrode 30 Vibration Member 40 Support member 54 Signal generator 60 Audio information 61 First audio information 61a First reproduction sound information 61b First sound field formation area information 62 Second audio information 62a Second reproduction sound information 62b Second sound field formation area information 63 3rd audio information 63a 3rd reproduction sound information 63b 3rd sound field formation area information 70 Actuator 72 Piezoelectric thin film layer 74 Upper movable electrode layer 76 Lower movable electrode layer 100 Audio output device

Claims (9)

A parametric speaker that oscillates an ultrasonic wave according to audio information and forms a sound field in which audio is reproduced by demodulating the ultrasonic wave;
A control unit that controls the parametric speaker so that the sound fields are formed in a plurality of regions, and different sounds are reproduced in the sound fields;
An audio output device comprising: The audio information is configured to include sound field forming area information indicating each of the plurality of areas,
The audio output device according to claim 1, wherein the control unit forms the sound field in each of the plurality of regions indicated by the sound field formation region information. The audio information is stereo audio information,
The control unit includes an analysis unit that analyzes the plurality of regions based on the audio information, and forms the sound field in each of the plurality of regions according to an analysis result by the analysis unit. The audio output device according to claim 1.   The audio output device according to any one of claims 1 to 3, wherein the plurality of regions in which the sound field is formed are sequentially switched over time.   5. The audio output device according to claim 1, wherein the control unit also performs control to change a region in which the one sound field is formed over time. 6.   The audio output device according to claim 5, further comprising an actuator that changes an output direction of a sound wave from the parametric speaker. The parametric speaker has a plurality of oscillation devices that oscillate ultrasonic waves in an array,
Each oscillator is used to form the corresponding sound field,
The audio output device according to claim 1, wherein the sound field is formed in each of the plurality of regions in parallel in time series.   The audio output device according to claim 1, wherein the parametric speaker includes a piezoelectric vibrator as a vibrator.   8. The parametric speaker has a micro electro mechanical system (MEMS) as a vibrator, and a driving method thereof is a piezoelectric method, an electrostatic method, an electromagnetic method, or a heat conduction method. The audio output device according to claim 1.

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