JP2012029096A - Sound output device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a user listen a sound selectively independently of a distance between a parametric speaker and a structure and a distance between the parametric speaker and the user.SOLUTION: A sound output device 100 has a parametric speaker 10 that makes an ultrasonic wave, which is generated toward a surrounding structure (e.g. a ceiling 1), be reflected by the structure and then be demodulated to form an acoustic field 2 where a sound is reproduced. The sound output device 100 has first and second measurement sections, and a controller. The first measurement section measures a distance between the parametric speaker 10 and the structure as a first distance D1. The second measurement section measures a distance between the parametric speaker 10 and a user 9 as a second distance D2. The controller adjusts an incidence angle α of the ultrasonic wave to the structure depending on the measurement results by the first and second measurement sections so that the sound reaches the user 9 selectively.

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.

  For example, Patent Literature 1 includes an ultrasonic generator and a spheroid surface that reflects ultrasonic waves generated from the ultrasonic generator, and the ultrasonic wave reflected from the spheroid surface is transmitted to the ceiling surface of the room. It describes the technology that reflects the light and reaches the user. In this document, there is a description that the user can selectively hear the voice by doing in this way.

JP 2000-82162 A

  However, according to the technique of Patent Document 1, it is difficult to properly hear the user depending on the distance between the spheroid surface and the ceiling surface and the distance between the spheroid surface and the user.

  An object of the present invention is to allow a user to selectively hear a voice regardless of the distance between a parametric speaker and a structure (such as a ceiling) that reflects ultrasonic waves and the distance between the parametric speaker and the user. An object is to provide a possible audio output device.

According to the present invention, a parametric speaker that forms a sound field in which sound is reproduced by demodulating an ultrasonic wave oscillated toward a surrounding structure after being reflected by the structure;
A first measurement unit that measures a first distance that is a distance between the parametric speaker and the structure;
A second measuring unit that measures a second distance that is a distance between the parametric speaker and a user located in a direction different from the structure as viewed from the parametric speaker;
A control unit that adjusts an incident angle of the ultrasonic wave with respect to the structure according to a measurement result by the first and second measurement units, and selectively sends the sound to the user;
An audio output device is provided.

  ADVANTAGE OF THE INVENTION According to this invention, a user can selectively hear a voice irrespective of the distance of the structure which reflects a parametric speaker and an ultrasonic wave, and the distance of a parametric speaker and a user.

It is a typical side view 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 typical top view which shows the parametric speaker which the audio | voice output apparatus which concerns on 1st Embodiment has. 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 flowchart which shows the flow of operation | movement of the audio | voice output apparatus which concerns on 1st Embodiment. It is a figure which shows the relationship between the rigidity of the structure which an ultrasonic wave reflects, a reflectance, and a reflection angle. It is a typical side view for demonstrating the audio | voice output apparatus which concerns on 2nd Embodiment. It is a flowchart which shows the flow of operation | movement of the audio | voice output apparatus which concerns on 2nd Embodiment. It is a flowchart which shows the flow of operation | movement of the audio | voice output apparatus which concerns on 3rd Embodiment. It is a typical side view for demonstrating the audio | voice output apparatus which concerns on 4th Embodiment. It is a flowchart which shows the flow of operation | movement of the audio | voice output apparatus which concerns on 4th Embodiment. It is a typical top view for demonstrating the audio | voice output apparatus which concerns on 5th Embodiment. It is a flowchart which shows the flow of operation | movement 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 5th 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 side view 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 sound output device 100 according to the first embodiment is a sound that reproduces sound by demodulating an ultrasonic wave oscillated toward a surrounding structure (for example, the ceiling 1) after reflecting the reflected sound from the structure. It has a parametric speaker 10 that forms the field 2. The audio output device 100 further includes first and second measurement units and a control unit 6. The first measurement unit measures a first distance D1 that is a distance between the parametric speaker 10 and the structure. The second measuring unit measures a second distance D2 that is a distance between the parametric speaker 10 and the user 9 located in a direction different from the structure as viewed from the parametric speaker 10. The control unit 6 adjusts the incident angle of the ultrasonic wave with respect to the structure according to the measurement results by the first and second measurement units so that the voice can be selectively delivered to the user 9. The audio output device 100 may be various electronic devices such as a laptop personal computer, a mobile phone, a PDA (Personal Digital Assistant), and a small game device. Alternatively, the audio output device 100 may be a sound source incorporated in some facility (building). Details will be described below.

  FIG. 1 shows an example in which the audio output device 100 is a laptop personal computer. In this case, the audio output device 100 includes, for example, first and second casings 101 and 102 that are connected to each other via a hinge mechanism (not shown) so as to be opened and closed. One housing 102 is a main body of the audio output device 100 and is placed on a desk 150 or the like. FIG. 1 shows a state in which the first and second casings 101 and 102 are opened to each other so that the angle between them is about 90 °. 1 (the left end of 1).

  The parametric speaker 10 is disposed on the upper surface of the housing 102, for example. As will be described in detail later, the parametric speaker 10 includes a first distance measurement oscillator 81 and an ultrasonic sensor 82 that are included in an array with the other oscillators 11. Yes. For this reason, ultrasonic waves can be output upward from the oscillation device 81 (that is, toward the ceiling 1). Further, the ultrasonic sensor 82 can detect the ultrasonic wave reflected and bounced above.

  In addition, on one surface of the housing 101, for example, a display unit 7 constituted by a liquid crystal display device or other display devices, and first and second imaging devices 91 and 92 constituting a second measurement unit are provided. It has been. Here, it is assumed that the user 9 is located in front of one surface of the housing 101. Therefore, in the state of FIG. 1, the user 9 is positioned in front of the first and second imaging devices 91 and 92 so that the first and second imaging devices 91 and 92 can capture the user 9. It has become.

The first measurement unit includes the oscillation device 81, the ultrasonic sensor 82, and the control unit 6, and measures a first distance D1 that is a distance between the parametric speaker 10 and the ceiling 1. That is, the control unit 6 outputs the ultrasonic wave from the oscillation device 81 toward the ceiling 1, and then based on the time and sound speed until the ultrasonic wave bounced off the ceiling 1 is detected by the ultrasonic sensor 82. The first distance D1 is calculated.
In this way, the first measurement unit measures the first distance D1 by detecting the ultrasonic wave output from the first measurement unit to the ceiling 1 and rebounding from the ceiling 1.

On the other hand, the second measurement unit is configured by the first and second imaging devices 91 and 92 and the control unit 6, and measures a second distance D <b> 2 that is a distance between the parametric speaker 10 and the user 9. In order to measure the second distance D2, images of the user 9 are acquired by simultaneously capturing images with the first and second imaging devices 91 and 92, respectively. These images are input to the control unit 6, and the control unit 6 performs image recognition using these images, thereby calculating the distance from the housing 101 to the user 9. In this image recognition, for example, the control unit 6 extracts the face of the user 9 from the image, recognizes the position of the extracted face, and calculates the distance to the face.
Here, in the state where the first and second casings 101 and 102 are opened as shown in FIG. 1, the horizontal distance D3 from the parametric speaker 10 to the casing 101 is stored and held in advance by the control unit 6. ing. The control unit 6 obtains the second distance D2 by subtracting the distance D3 from the distance from the casing 101 to the user 9 obtained by calculation.
The control unit 6 also calculates and recognizes the direction of the user 9 viewed from the audio output device 100 based on the images obtained by the first and second imaging devices 91 and 92.

  FIG. 3 is a schematic plan view showing the parametric speaker 10 included in the audio output device 100 according to the first embodiment.

  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. The ultrasonic wave oscillated (output) from the oscillating device 11 of the parametric speaker 10 is reflected by the ceiling 1 and then demodulated to form a sound field 2.

  Further, the parametric speaker 10 includes an oscillation device 81 and an ultrasonic sensor 82 for measuring the first distance together with the oscillation device 11 in an array. Note that the oscillator 81 and the ultrasonic sensor 82 are preferably elements adjacent to each other in order to increase the measurement accuracy of the first distance D1.

  Here, as shown in FIG. 2, the audio output device 100 further includes an angle adjusting actuator 60 that adjusts the direction of the parametric speaker 10. The angle adjusting actuator 60 is constituted by, for example, a motor or the like. By controlling the angle adjusting actuator 60 by the control unit 6 and adjusting the direction of the parametric speaker 10 by the angle adjusting actuator 60, the incident angle of the ultrasonic wave output from the parametric speaker 10 and incident on the ceiling 1. α (FIG. 1) can be adjusted.

  For example, the region where the sound field 2 is formed can be closer to the audio output device 100 as the incident angle α is closer to 90 °. Further, the region where the sound field 2 is formed can be further away from the audio output device 100 as the incident angle α is smaller than 90 °.

  The control unit 6 calculates the incident angle α of the ultrasonic wave with respect to the ceiling 1 according to the measurement results by the first and second measuring units, and the ultrasonic wave is incident on the ceiling 1 at the incident angle α. The directivity of the parametric speaker 10 is controlled. Thereby, the voice is selectively delivered to the user 9. That is, the sound field 2 is formed near the user 9.

  FIG. 4 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 electrical signal input to the vibrator 20, that is, a modulation signal in the parametric speaker 10. 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. 5 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.

  Note that the oscillation device 81 and the ultrasonic sensor 82 have the same vibration member 30, vibrator 20 and support member 40 as the oscillation device 11, respectively. However, since the ultrasonic wave oscillated from the oscillation device 81 does not need to be demodulated, it may be an ultrasonic wave having an arbitrary constant wavelength. Further, the ultrasonic sensor 82 is not connected to the signal generation unit 54 because it does not need to oscillate ultrasonic waves and can detect ultrasonic waves.

  Next, a series of operations will be described.

  FIG. 6 is a flowchart showing an operation flow of the audio output device 100 according to the first embodiment.

  First, the first distance D1 is measured. For this purpose, first, the control unit 6 controls the angle adjusting actuator 60 to adjust the direction of the parametric speaker 10 upward. In this state, under the control of the control unit 6, ultrasonic waves for measurement of the first distance D <b> 1 are oscillated from the oscillation device 81 toward the ceiling 1. Then, the ultrasonic sensor 82 detects the ultrasonic wave that has bounced off the ceiling 1. The control unit 6 calculates the first distance D1 based on the time from when the ultrasonic wave is oscillated until it is detected and the sound speed (step S11).

  Next, the second distance D2 is measured. That is, under the control of the control unit 6, the first and second imaging devices 91 and 92 cause the user 9 to take an image. Then, the second distance D2 is calculated by image processing on the images obtained by the imaging (step S12).

  Next, the control unit 6 calculates the incident angle α of the ultrasonic wave with respect to the ceiling 1 according to the first and second distances D1 and D2 (step S13).

  Next, the direction of the parametric speaker 10 is adjusted so that the ultrasonic wave is incident on the ceiling 1 at the incident angle α calculated in the previous step S <b> 13, and the ultrasonic wave is oscillated from each oscillation device 11 of the parametric speaker 10. (Step S14).

  As a result, the sound field 2 is selectively formed in the vicinity of the user 9. That is, a private sound field 2 dedicated to the user 9 can be formed. Therefore, it is possible to prevent the voice from being heard by a third party.

  According to the first embodiment described above, the audio output device 100 includes the first measurement unit that measures the first distance D1, the second measurement unit that measures the second distance D2, and the first and second measurement units. The control unit 6 is configured to adjust the incident angle α of the ultrasonic wave with respect to the ceiling 1 according to the measurement result of and to selectively send the sound to the user 9. That is, the control unit 6 controls the directivity of the parametric speaker 10 so that the sound field 2 is selectively formed in the vicinity of the user 9 according to the first and second distances D1 and D2. Therefore, the private sound field 2 can be formed at the position of the user 9 regardless of the first distance D1 and the second distance D2, and the user 9 can be selectively heard.

[Second Embodiment]
FIG. 7 is a diagram showing the relationship between the rigidity of a structure that reflects ultrasonic waves, the reflectance, and the reflection angle. FIG. 8 is a schematic side view for explaining the audio output device 100 according to the second embodiment.

  As indicated by a curve L2 in FIG. 7, the greater the rigidity of the structure, the smaller the reflection angle β (see FIG. 8) when the ultrasonic wave is reflected by the structure.

  FIGS. 8A and 8B schematically show a reflection angle β when an ultrasonic wave is incident on a structure (for example, the ceiling 1) having different rigidity from each other at the same incident angle α.

  As shown in FIG. 8A, when an ultrasonic wave is incident on the ceiling 1 with a certain angle at an incident angle α, the reflection angle β is assumed to be the size shown in FIG. When ultrasonic waves are incident on the ceiling 1 having a lower rigidity than that in the case of FIG. 8A at the same incident angle α, the reflection angle β becomes larger than that in the case of FIG.

  For this reason, if the sound field 2 is formed at an optimum position (in the vicinity of the user 9) in the case of FIG. 8A, the sound field 2 is formed in the case of FIG. 8B. The position will deviate from the optimal position. For example, in the example of FIG. 8B, the sound field 2 is further away from the sound output device 100 than in the case of FIG. 8A, and the sound field 2 is shifted to the back side of the user 9.

  Therefore, when the ceiling 1 having a small rigidity is used (FIG. 8B), the incident angle α may be corrected in order to form the sound field 2 at the same position as in FIG. That is, for example, as shown in FIG. 8C, it is preferable to correct in the direction in which the incident angle α increases.

  On the other hand, as indicated by a curve L1 in FIG. 7, the greater the rigidity of the structure (for example, the ceiling 1), the greater the reflectance of the ultrasonic wave at the structure (in other words, the smaller the attenuation). There is.

  That is, the reflectance and the reflection angle β have a negative correlation with each other.

  Therefore, in the present embodiment, the control unit 6 determines the reflectance due to the reflection of the ultrasonic wave by the structure, and corrects the incident angle α (FIG. 8) according to the determined reflectance. The control unit 6 stores and holds in advance an arithmetic expression for calculating an appropriate value of the incident angle α in accordance with the reflectance.

  In order to determine the reflectance at the ceiling 1, an ultrasonic wave is oscillated from the oscillating device 81 with the parametric speaker 10 adjusted upward, and the reflected wave reflected by the ceiling 1 is converted into an ultrasonic sensor 82. To detect. Here, the amplitude of the reflected wave is detected by the ultrasonic sensor 82, and the control unit 6 determines the reflectance based on this amplitude.

  Next, a series of operations in the case of the second embodiment will be described.

  FIG. 9 is a flowchart showing an operation flow of the audio output device 100 according to the second embodiment.

  First, the first distance D1 is measured in the same manner as in step S11 of the first embodiment (step S21).

  Next, the reflectance of the ceiling 1 is determined by the method described above (step S22).

  Next, the second distance D2 is measured in the same manner as in step S12 of the first embodiment (step S23).

  Next, a provisional value of the incident angle α of the ultrasonic wave with respect to the ceiling 1 is calculated according to the first and second distances D1 and D2. The provisional value is calculated in the same manner as the calculation of the incident angle α in step S13 of the first embodiment (step S24).

  Next, the control part 6 calculates | requires the correction value of incident angle (alpha) by a calculation according to the reflectance determined by previous step S22 (step S25).

  Next, the control unit 6 adjusts the direction of the parametric speaker 10 so that the ultrasonic wave is incident on the ceiling 1 at the incident angle α (after correction) calculated in the previous step S25. Ultrasonic waves are oscillated from the oscillation device 11 (step S26).

  As a result, the formation position of the sound field 2 can be corrected according to the reflectance so that the sound field 2 is selectively formed in the vicinity of the user 9.

  According to the second embodiment described above, the reflectance due to the reflection of the ultrasonic wave by the structure is determined, and the incident angle α is corrected according to the reflectance. Therefore, the reflectance (rigidity) of the structure is increased. Regardless, the sound field 2 can be formed at an optimum position.

[Third Embodiment]
In the second embodiment, the example in which the incident angle α is corrected according to the reflectance of the structure has been described. However, in the third embodiment, in addition to this, sound is generated according to the reflectance of the structure. An example of adjusting the pressure will be described.

  The greater the reflectance of the structure (the smaller the attenuation), the greater the sound pressure of the audible sound reproduced in the sound field 2. For this reason, by controlling the sound pressure in accordance with the reflectance, it is possible to reproduce the sound with the optimum sound pressure (volume), and to lead to energy saving of the sound output device 100.

The sound pressure is adjusted by adjusting the number of oscillating devices 11 that oscillate ultrasonic waves among the oscillating devices 11 of the parametric speaker 10 or by adjusting the amplitude of the voltage of a signal input to each transducer 20. This can be done by adjusting the amplitude of vibration of the child 20.
The control unit 6 stores in advance, as a table, the number of oscillation devices 11 that oscillate or the amplitude of the voltage of the input signal to each transducer 20 for each of various reflectivities, and refer to this table. Thus, the operation of each oscillation device 11 is controlled according to the reflectance.

  FIG. 10 is a flowchart showing an operation flow of the audio output device 100 according to the third embodiment. Hereinafter, a series of operations in this embodiment will be described.

  In the case of this embodiment, steps S21 to S25 are performed in the same manner as in the second embodiment.

  Subsequently, the control unit 6 adjusts the sound pressure in accordance with the reflectance determined in the previous step S22 (step S36).

  Next, the control unit 6 oscillates an ultrasonic wave from each oscillation device 11 so that the incident angle α corrected in the previous step S25 and the sound pressure adjusted in the previous step S36 are obtained. (Step S37).

  According to the third embodiment as described above, the reflectivity due to the reflection of the ultrasonic waves by the structure is determined, and the sound pressure of the sound is controlled according to the reflectivity. ), The sound field 2 having the optimum sound pressure can be formed.

[Fourth Embodiment]
FIG. 11 is a schematic side view for explaining the audio output device 100 according to the fourth embodiment.

In each of the above-described embodiments, an example has been described in which a structure that reflects ultrasonic waves output from the parametric speaker 10 is determined in advance (for example, only the ceiling 1).
On the other hand, in the fourth embodiment, ultrasonic waves are respectively reflected by a plurality of structures (for example, the ceiling 1, the left wall 3 of the user 9, and the right wall 4 of the user 9). The reflectance is determined, and the ultrasonic wave is reflected by a structure having the reflectance satisfying a predetermined condition.

  As shown in FIG. 11, in the case of the present embodiment, the audio output device 100 includes a parametric speaker 430 provided on one side surface of the housing 102 in addition to the configuration of the first embodiment (FIG. 1). And a parametric speaker 440 provided on the other side surface of the housing 102. These parametric speakers 430 and 440 are configured in the same manner as the parametric speaker 10. Therefore, the parametric speakers 430 and 440 have the distance measuring oscillator 81 and the ultrasonic sensor 82.

  Although not shown, the audio output device 100 further includes an angle adjustment actuator for adjusting the direction of the parametric speaker 430 and an angle adjustment actuator for adjusting the direction of the parametric speaker 440. Yes.

  When an ultrasonic wave is oscillated from the oscillating device 81 of the parametric speaker 430 toward the wall 3 on the side of the audio output device 100 (left side as viewed from the user 9), the ultrasonic wave bounced off the wall 3 is transmitted to the parametric speaker 430. The ultrasonic sensor 82 detects. The control unit 6 can calculate the reflectance at the wall 3 and the distance D4 from the parametric speaker 430 to the wall 3 based on the detection result by the ultrasonic sensor 82.

  Similarly, when an ultrasonic wave is oscillated from the oscillating device 81 of the parametric speaker 440 toward the wall 4 on the side of the audio output device 100 (right side as viewed from the user 9), the ultrasonic wave rebounding on the wall 4 is The ultrasonic sensor 82 of the parametric speaker 440 detects it. The control unit 6 can calculate the reflectance at the wall 4 and the distance D5 from the parametric speaker 440 to the wall 4 based on the detection result by the ultrasonic sensor 82.

  In the case of the present embodiment, the control unit 6 determines the structure satisfying a predetermined condition among the reflectances of the ceiling 1, the wall 3 and the wall 4, and then toward the structure. An ultrasonic field is oscillated to form the sound field 2.

  The operation of this embodiment will be described below. FIG. 12 is a flowchart showing an operation flow of the audio output device 100 according to the fourth embodiment.

  First, the reflectances of the ceiling 1, the wall 3, and the wall 4 are determined. That is, ultrasonic waves are output from the oscillation devices 81 of the parametric speakers 10, 430, and 440 to the ceiling 1, the walls 3, and the walls 4, and the reflected waves are detected by the ultrasonic sensors 82, and the detection results thereof. Based on the above, the reflectances of the ceiling 1, the wall 3 and the wall 4 are determined (step S41).

  Next, the control part 6 determines the structure from which the reflectance satisfy | fills a predetermined condition among the ceiling 1, the wall 3, and the wall 4 as an ultrasonic reflective surface (step S42). For example, a structure having the highest reflectivity can be used as the reflecting surface. Hereinafter, the description will be continued assuming that the wall 4 (FIG. 11) is determined as the reflecting surface.

  Next, the distance D5 between the determined reflecting surface, that is, the wall 4 and the parametric speaker 440 is measured. That is, an ultrasonic wave is oscillated toward the wall 4 from the oscillation device 81 of the parametric speaker 440, and an ultrasonic wave bounced off the wall 4 is detected by the ultrasonic sensor 82 of the parametric speaker 440, and the control unit 6 detects this. A distance D5 is calculated based on the result (step S43). In the present embodiment, this distance D5 is the first distance.

  Next, the second distance D2 is measured (step S44) as in step S12 of the first embodiment.

  Next, the control unit 6 calculates the incident angle α of the ultrasonic wave with respect to the wall 4 according to the first and second distances D5 and D2 (step S45).

  Next, the direction of the parametric speaker 440 is adjusted by the angle adjusting actuator so that the ultrasonic wave is incident on the wall 4 at the incident angle α calculated in the previous step S45, and each oscillation device 11 of the parametric speaker 440 is adjusted. Ultrasonic waves are oscillated (step S46).

  As a result, the sound field 2 is selectively formed in the vicinity of the user 9.

  According to the fourth embodiment, the structure that satisfies the predetermined condition for the reflectance is determined as the reflecting surface, so that the sound field 2 can be more appropriately formed.

[Fifth Embodiment]
FIG. 13 is a schematic plan view for explaining an audio output device 100 according to the fifth embodiment.

In each of the above embodiments, an example in which ultrasonic waves are reflected by any one structure has been described.
On the other hand, in the fifth embodiment, the sound field 2 is formed by reflecting ultrasonic waves at each of the plurality of structural portions.

  In the case of this embodiment, for example, as shown in FIG. 13, the sound field 2 is formed by reflecting ultrasonic waves on the left and right walls 3 and 4, respectively. For this reason, the audio output device 100 according to the present embodiment includes the parametric speakers 430 and 440 as in the case of the fourth embodiment.

  The operation of this embodiment will be described below. FIG. 14 is a flowchart showing an operation flow of the audio output device 100 according to the fifth embodiment.

  First, the distance D4 from the parametric speaker 430 to the wall 3 is measured (step S51). Next, the distance D5 from the parametric speaker 440 to the wall 4 is measured (step S52). Next, the second distance D2 is measured (step S53).

  Next, the control part 6 calculates the incident angle of the ultrasonic wave with respect to the wall 3 according to the distance D4 and the 2nd distance D2 (step S54). Similarly, the control part 6 calculates the incident angle of the ultrasonic wave with respect to the wall 4 according to the distance D5 and the 2nd distance D2 (step S55).

  Next, the direction of the parametric speaker 430 is adjusted so that the ultrasonic wave is incident on the wall 3 at the incident angle calculated in the previous step S54, and the ultrasonic wave is oscillated from each oscillation device 11 of the parametric speaker 430. Similarly, the direction of the parametric speaker 440 is adjusted so that the ultrasonic wave enters the wall 4 at the incident angle calculated in the previous step S55, and the ultrasonic wave is oscillated from each oscillation device 11 of the parametric speaker 440 ( Step S56).

  As a result, the sound field 2 is selectively formed in the vicinity of the user 9 by the cooperation of the parametric speakers 430 and 440.

  According to the fifth embodiment described above, since the sound field 2 is formed by reflecting ultrasonic waves with a plurality of structures, for example, it is possible to produce an acoustic effect such that sound can be heard from a plurality of directions. .

[Sixth Embodiment]
The oscillation device 11 of the audio output device 100 according to the present embodiment has a MEMS (Micro Electro Mechanical Systems) actuator 70 shown in FIG. In other respects, the audio output device 100 according to this embodiment is configured in the same manner as the audio output device 100 according to each of the above embodiments.

  In the example shown in FIG. 15, 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 above embodiment, an example in which the audio output device 100 is a personal computer has been described. However, when the audio output device 100 is a mobile terminal device or the like, the sound field 2 is formed by reflecting ultrasonic waves on the floor of the building. You can also

DESCRIPTION OF SYMBOLS 1 Ceiling 2 Sound field 3 Wall 4 Wall 6 Control part 7 Display part 9 User 10 Parametric speaker 11 Oscillator 20 Vibrator 22 Piezoelectric body 24 Upper surface electrode 26 Lower surface electrode 30 Vibration member 40 Support member 54 Signal generation part 60 For angle adjustment Actuator 70 Actuator 72 Piezoelectric thin film layer 74 Upper movable electrode layer 76 Lower movable electrode layer 81 Oscillator 82 Ultrasonic sensor 91 First imaging device 92 Second imaging device 100 Audio output device 101 Housing 102 Housing 150 Desk 430 Parametric speaker 440 Parametric speaker

Claims (10)

A parametric speaker that forms a sound field in which sound is reproduced by demodulating the ultrasonic wave oscillated toward the surrounding structure after being reflected by the structure;
A first measurement unit that measures a first distance that is a distance between the parametric speaker and the structure;
A second measuring unit that measures a second distance that is a distance between the parametric speaker and a user located in a direction different from the structure as viewed from the parametric speaker;
A control unit that adjusts an incident angle of the ultrasonic wave with respect to the structure according to a measurement result by the first and second measurement units, and selectively sends the sound to the user;
An audio output device comprising:   The first measurement unit measures the first distance by detecting an ultrasonic wave output from the first measurement unit to the structure and rebounding from the structure. The audio output device according to 1.   The said 2nd measurement part has a some imaging device, and measures the said 2nd distance by the image recognition with respect to the image imaged by these some imaging device, The Claim 1 or 2 characterized by the above-mentioned. Audio output device.   The audio output device according to claim 1, wherein the structure is a ceiling, a wall, or a floor of a building. A reflectance determination unit that determines reflectance by reflecting the ultrasonic wave on the structure;
5. The audio output device according to claim 1, wherein the control unit corrects the incident angle according to the reflectance. 6. A reflectance determination unit that determines reflectance by reflecting the ultrasonic wave on the structure;
The sound output apparatus according to claim 1, wherein the control unit controls a sound pressure of the sound according to the reflectance. A reflectance determination unit that determines reflectance by reflecting the ultrasonic waves by the plurality of structures, respectively;
The audio output device according to claim 1, wherein the control unit causes the ultrasonic wave to be output to the structure in which the reflectance satisfies a predetermined condition.   The sound output device according to claim 1, wherein the control unit reflects the ultrasonic waves from a plurality of the structures to form the sound field.   9. The audio output device according to claim 1, wherein the parametric speaker includes a piezoelectric vibrator as a vibrator.   The parametric speaker has MEMS (Micro Electro Mechanical Systems) 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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