JP2021166318A - Ultrasonic controller, ultrasonic speaker, and program - Google Patents

Abstract

To control the ultrasonic distribution around a focal point.SOLUTION: Disclosed is an ultrasonic controller for controlling an ultrasonic transducer array which emits an ultrasonic wave focused on at least one focal point of an arbitrary position on a space. The controller includes means for calculating a focal point coordinate of the focal point and a control point coordinate of at least one control point. The sound pressure of the control point is lower than that of the focal point. The means is provided which is for generating a control parameter for controlling each ultrasonic transducer based on the focal point coordinate and the control point coordinate. The means is also provided which is for individually controlling each ultrasonic transducer so as to radiate the ultrasonic wave focused on the focal point based on the control parameter of each ultrasonic transducer.SELECTED DRAWING: Figure 4

Description

The present invention relates to an ultrasonic controller, an ultrasonic speaker, and a program.

An ultrasonic speaker that emits directional ultrasonic waves is known. The ultrasonic speaker can generate an audible sound in a specific range. In particular, an ultrasonic speaker capable of forming a point sound source at a focal point by radiating an ultrasonic wave focused at a specific focal point is attracting attention.
Generally, the focus is set near the listener's ears. Therefore, it is desirable for the ultrasonic speaker to suppress the sound pressure of ultrasonic waves.

For example, Patent Document 1 discloses a technique for suppressing a grating lobe in order to suppress the sound pressure of ultrasonic waves.

Japanese Unexamined Patent Publication No. 2003-23689

However, in Patent Document 1, although it is possible to suppress the audible sound beam in an unintended direction, the ultrasonic distribution around the focal point is not intended to be distributed. In this case, a high sound pressure region is formed around the focal point.

The high sound pressure region causes abnormal noise for the listener around the focal point.
Further, since the high sound pressure region expands the region where the audible sound is generated, it is difficult to locally generate the audible sound.

As described above, the conventional ultrasonic speaker cannot control the ultrasonic distribution around the focal point.

An object of the present invention is to control the ultrasonic distribution around the focal point.

One aspect of the present invention is
An ultrasonic controller that controls an ultrasonic transducer array having a plurality of ultrasonic transducers that emit ultrasonic waves focused on at least one focal point at an arbitrary position in space.
A means for calculating the focal coordinates of the focal point and the control point coordinates of at least one control point is provided.
The sound pressure at the control point is lower than the sound pressure at the focal point.
A means for generating control parameters for controlling each ultrasonic vibrator based on the focal coordinates and the control point coordinates is provided.
A means for individually controlling each ultrasonic vibrator so as to radiate an ultrasonic wave focused on the focal point based on the control parameters of each ultrasonic vibrator is provided.
It is an ultrasonic controller.

According to the present invention, the ultrasonic distribution around the focal point can be controlled.

It is a system block diagram of the audio system of this embodiment. It is a block diagram which shows the structure of the audio system of FIG. It is a schematic block diagram of the ultrasonic speaker of FIG. It is explanatory drawing of the outline of this embodiment. It is explanatory drawing of the control principle of the ultrasonic controller of FIG. It is explanatory drawing of the method of determining the oscillation timing of the ultrasonic speaker of FIG. It is explanatory drawing of the method of determining the oscillation timing of the ultrasonic speaker of FIG. It is explanatory drawing of the operation example 1 of the ultrasonic speaker of this embodiment. It is a figure which shows the sound source formed in the operation example 1 of FIG. It is explanatory drawing of the operation example 2 of the ultrasonic speaker of this embodiment. It is a figure which shows the sound source formed in the operation example 2 of FIG. It is a flowchart of the control process of the audio system of this embodiment. It is the schematic of the sound pressure information and the 1st surround pan parameter referred to in the process of FIG. It is the schematic of the sound pressure information divided into the 1st frequency band to the 3rd frequency band in the processing of FIG. It is the schematic of the 2nd surround pan parameter generated in the process of FIG. It is explanatory drawing of the action effect of the modification 5.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In addition, in the drawing for demonstrating the embodiment, the same components are in principle the same reference numerals, and the repeated description thereof will be omitted.

(1) Configuration of audio system The configuration of the audio system will be described. FIG. 1 is a system configuration diagram of the audio system of the present embodiment. FIG. 2 is a block diagram showing the configuration of the audio system of FIG.

As shown in FIG. 1, the audio system 1 is installed in the usage environment SP. The audio system 1 is located in front of the listener L.
As shown in FIG. 2, the audio system 1 includes an ultrasonic controller 10, an ultrasonic speaker 21, a loudspeaker 22, a sound source 23, a camera 24, a position detection unit 25, and a woofer 26.

The ultrasonic controller 10 is an example of an information processing device that controls a speaker set (ultrasonic speaker 21, loudspeaker 22, and woofer 26).
The ultrasonic controller 10 includes a storage device 11, a processor 12, an input / output interface 13, and a communication interface 14.

The storage device 11 is configured to store programs and data. The storage device 11 is, for example, a combination of a ROM (Read Only Memory), a RAM (Random Access Memory), and a storage (for example, a flash memory or a hard disk).

The program includes, for example, the following program.
-OS (Operating System) program-Program of an application that executes information processing (for example, a control application that controls the audio system 1)

The data includes, for example, the following data.
-Database referenced in information processing-Data obtained by executing information processing (that is, the execution result of information processing)

The processor 12 is configured to realize the function of the ultrasonic controller 10 by activating the program stored in the storage device 11. The processor 12 is an example of a computer.

The input / output interface 13 receives an input signal from an input device (speaker 23, a camera 24, and a position detection unit 25) connected to the ultrasonic controller 10, and an output device (super) connected to the ultrasonic controller 10. It is configured to output an output signal to the sound sound speaker 21 and the loudspeaker 22).

The communication interface 14 is configured to control communication between the ultrasonic controller 10 and a server (not shown).

The ultrasonic speaker 21 is configured to emit ultrasonic waves under the control of the ultrasonic controller 10.

The loudspeaker 22 and the woofer 26 are configured to generate an audible sound under the control of the ultrasonic controller 10.

The sound source 23 is configured to give an audio signal to the ultrasonic controller 10. The sound source 23 includes the following.
・ TV / audio media players (cassette players, CD (Compact Disc) players, DVD (Digital Versatile Disc) players, Blu-ray disc players)
・ Digital audio player

The camera 24 is configured to acquire image information of the usage environment SP. The camera 24 is, for example, a CMOS (Complementary MOS) camera.

The position detection unit 25 is configured to detect the position of a person.
The position detection unit 25 is, for example, an infrared sensor. When the infrared sensor irradiates infrared rays and receives the reflected light of infrared rays, the infrared sensor generates an electric signal according to the reflected light. As a result, the position of the person is detected.

(1-1) Configuration of Ultrasonic Speaker The configuration of the ultrasonic speaker of the present embodiment will be described. FIG. 3 is a schematic configuration diagram of the ultrasonic speaker of FIG.

As shown in FIG. 3, a cover 21a (FIG. 3A) is arranged on the radiation surface of the ultrasonic speaker 21. When the cover 21a is removed, the radial surface (FIG. 3B) on the housing 21b is exposed.

On the radiation surface, an oscillator array FA including N ultrasonic oscillators TR (N is an integer of 2 or more) is arranged. The ultrasonic transducer TR (n) (n is an integer of 1 to N) is arranged in the XZ plane (hereinafter referred to as “array plane”).

The ultrasonic speaker 21 includes a drive unit (not shown) that drives each ultrasonic vibrator TR (n). The drive unit drives each ultrasonic vibrator TR (n) individually. Each ultrasonic vibrator TR (n) generates ultrasonic waves by oscillating according to the drive of the drive unit. The ultrasonic waves radiated from each ultrasonic vibrator TR (n) propagate in space and are focused at a focal point in space. Ultrasound focused at the focal point forms a sound source of audible sound.

(2) Outline of the present embodiment The outline of the present embodiment will be described. FIG. 4 is an explanatory diagram of an outline of the present embodiment. FIG. 5 is an explanatory diagram of the control principle of the ultrasonic controller of FIG.

As shown in FIG. 4, the sound source 23 gives an audio signal to the ultrasonic controller 10.

The ultrasonic controller 10 inputs position information (x0, y0, z0) regarding a position in space where a sound source should be formed.
The position information (x0, y0, z0) is given to the ultrasonic controller 10 by, for example, at least one of the following.
-Instruction of the operator operating the ultrasonic controller 10-Signal pattern of the input signal / audio signal input from the input device (at least one of the sound source 23, the camera 24, and the position detection unit 25).

Based on the input position information, the ultrasonic controller 10 has the focal coordinates (xfp, yfp, zfp) of at least one focal point FP and the control point coordinates (xcp (m)) of at least one control point CP (m). , Ycp (m), zcp (m)). m is an identifier (positive integer) of the control point CP. The control point CP is a point where the sound pressure of the ultrasonic wave is lower than the sound pressure of the ultrasonic wave focused on the focal point FP. The sound pressure of ultrasonic waves focused on the focal point FP (hereinafter referred to as "focus sound pressure") is SPfp, and the sound pressure of ultrasonic waves at the control point CP (hereinafter referred to as "control point sound pressure") is SPcp. Meet the relationship. That is, the ultrasonic controller 10 forms a control point CP having a control point sound pressure SPcp smaller than the focal sound pressure SPfp in space in addition to the focal FP.
0 ≦ SPcp / SPfp <1 ... (Equation 1)

The ultrasonic controller 10 controls each ultrasonic transducer TR (n) based on the focal coordinates (xfp, yfp, zfp) and the control point coordinates (xcp (m), ycp (m), zcp (m)). Generate the parameter PAR (n). The control parameter PAR (n) includes at least one of the oscillation amplitude A (n) and the oscillation phase P (n) of the ultrasonic vibrator TR (n).
The ultrasonic controller 10 outputs the control parameter PAR (n) to each ultrasonic vibrator TR (n).

Each ultrasonic vibrator TR (n) oscillates according to the control parameter PAR (n). As a result, the ultrasonic wave USW based on the control parameter PAR (n) is emitted from the vibrator array FA. The ultrasonic USW radiated from the oscillator array FA is focused at the focal point FP. As a result, the space in which the focal point FP is formed behaves as a sound source.
On the other hand, the ultrasonic waves radiated from the vibrator array FA weaken each other at the control point CP, so that the ultrasonic waves are generated in the area (hereinafter referred to as “control area”) CA in the space where the control point CP (m) is formed. Sound pressure is reduced. As a result, the listener L can hear the audible sound only in the vicinity of the focal FP, and the sound pressure of the ultrasonic waves in the vicinity of the focal FP at a position other than the focal FP can be reduced. ..

(3) Control of ultrasonic speaker The control of the ultrasonic speaker of the present embodiment will be described.

(3-1) Generation of Control Parameters for Ultrasonic Speaker The generation of control parameters for the ultrasonic speaker of the present embodiment will be described.

The ultrasonic speaker 21 emits ultrasonic waves modulated by a predetermined modulation method.
The modulation method is, for example, any of the following.
・ AM (Amplitude Modulation) modulation ・ FM (Frequency Modulation) modulation ・ PM (Phase Modulation) modulation

(3-1-1) First Example of Generation of Control Parameters A first example of generation of control parameters of the present embodiment will be described.

The ultrasonic controller 10 individually controls the oscillation timings of the plurality of ultrasonic transducers TR (n) to give an oscillation phase difference to the ultrasonic waves radiated from each ultrasonic transducer TR (n). The focal position and the number of focal points depend on this oscillation phase difference. That is, the ultrasonic speaker 21 can change the focal position and the number of focal points by controlling the oscillation phase difference.

A method of forming the oscillation phase difference of the ultrasonic speaker 21 of the present embodiment will be described. 6 to 7 are explanatory views of a method of determining the oscillation timing of the ultrasonic speaker of FIG.

The storage device 11 has coordinates (xtr (n), ytr (n), indicating the relative position of the ultrasonic vibrator TR (n) on the vibrator array FA with respect to the reference point (for example, the center) of the vibrator array FA. ztr (n)) is stored. n is an identifier (positive integer) of the ultrasonic vibrator TR.

For example, when the operator operating the ultrasonic controller 10 gives an instruction to specify the focal point FP, the processor 12 indicates the focal coordinates (xfp,) indicating the relative position of the focal point FP with respect to the reference point, as shown in FIG. yfp, zfp) is determined.
The processor 12 includes the coordinates (xtr (n), ytr (n), ztr (n)) of the ultrasonic vibrator TR (n) stored in the storage device 11, and the focal lengths (xfp, yfp, zfp). The focal length r (n) between the ultrasonic transducer TR (n) and the focal point FP is calculated based on the above.

The processor 12 executes the acoustic hologram calculation using the focal coordinates (xfp, yfp, zfp) as an input, so that, for example, the focal sound pressure SPfp is maximized and the sound pressure in the control region within the focal FP predetermined range is increased. The control point coordinates (xcp (m), ycp (m), zcp (m)) of the control point CP (m) so as to be the minimum, the control point sound pressure SPcp (m) of the control point CP (m), and To determine.
The processor 12 has the coordinates (xtr (n), ytr (n), ztr (n)) of the ultrasonic vibrator TR (n) stored in the storage device 11 and the control point coordinates (xcp (m), ycp (xcp (m), ycp (n)). Based on m), zcp (m)) and the control point sound pressure SPcp (m), the control point distance q (n, m) between the ultrasonic vibrator TR (n) and each control point CP (m). ) Is calculated.

The processor 12 has a time difference between the oscillation timing of the n + 1th oscillating ultrasonic vibrator TR (n + 1) and the oscillation timing of the nth oscillating ultrasonic vibrator TR (n) (hereinafter referred to as “oscillation time difference”). ΔT (n + 1) is calculated using a function of focal coordinates and control point coordinates (for example, Equation 2). As shown in Equation 2, the oscillation time difference ΔT is, for example, a function of the focal length, the control point distance, and the speed of sound.
ΔT (n + 1) = f (r (n + 1), q (n + 1), c) ... (Equation 2)
・ C: Speed of sound ・ Focal length: r (n + 1)
・ Control point distance: q (n + 1)

As described above, the processor 12 has the focal coordinates (xfp, yfp, zfp), the control point coordinates (xcp (m), ycp (m), zcp (m)), and the coordinates (xtr) stored in the storage device 11. Using (n + 1), ytr (n + 1), ztr (n + 1)), the oscillation time difference ΔT (n + 1) of each ultrasonic transducer TR (n + 1) is calculated. The processor 12 supplies a drive signal to each ultrasonic vibrator TR (n + 1) according to the oscillation time difference ΔT (n + 1).

Each ultrasonic vibrator TR oscillates with a time difference according to this drive signal. Since the ultrasonic waves radiated from each ultrasonic vibrator TR have an oscillation phase difference corresponding to the oscillation time difference ΔT, they are focused at the focal point FP.

(3-1-2) Second Example of Generation of Control Parameters A second example of generation of control parameters of the present embodiment will be described.

The ultrasonic controller 10 individually controls the oscillation amplitudes A (n) of the plurality of ultrasonic transducers TR (n), so that the oscillation amplitude difference is different from the ultrasonic waves radiated from each ultrasonic transducer TR (n). give. The focal position and the number of focal points, and the control point position and the number of control points depend on this oscillation amplitude difference. That is, the ultrasonic speaker 21 can change the focal position and the number of focal points, the control point position, and the number of control points by controlling the oscillation amplitude difference.

A method of forming an oscillation amplitude difference of the ultrasonic speaker 21 of the present embodiment will be described.

The processor 12 performs the acoustic hologram calculation using the focal coordinates (xfp, yfp, zfp) as the input, as in the first example of generating the control parameters, so that the control point coordinates (xcp (m), ycp (xcp (m)), ycp ( m), zcp (m)) and the control point sound pressure SPcp (m) are determined.
The processor 12 calculates the control point distance q (n, m) in the same manner as in the first example of generating the control parameter.

The processor 12 calculates the oscillation amplitude difference ΔA (n + 1) between the oscillation amplitude A (n + 1) of the ultrasonic transducer TR (n + 1) and the oscillation amplitude A (n) of the ultrasonic transducer TR (n) in Equation 3. Use to calculate. As shown in Equation 3, the oscillation amplitude difference ΔA is a function of the focal length, the control point distance, the control point sound pressure SPcp (m), and the speed of sound.
ΔA (n + 1) = g (r (n + 1), q (n + 1), SPcp (m), c) ... (Equation 3)
・ C: Speed of sound ・ Focal length: r (n + 1)
・ Control point distance: q (n + 1)
・ Control point sound pressure: SPcp (m)

As described above, the processor 12 has the focal coordinates (xfp, yfp, zfp), the control point coordinates (xcp (m), ycp (m), zcp (m)), and the coordinates (xtr) stored in the storage device 11. Using (n + 1), ytr (n + 1), ztr (n + 1)) and the control point sound pressure SPcp (m), the oscillation amplitude difference ΔA (n + 1) of each ultrasonic transducer TR (n + 1) is calculated. .. The processor 12 supplies a drive signal to each ultrasonic vibrator TR (n + 1) according to the oscillation amplitude difference ΔA (n + 1).

Each ultrasonic vibrator TR oscillates at the same time in response to this drive signal. Since the ultrasonic waves radiated from each ultrasonic vibrator TR have an oscillation amplitude difference ΔA, they are focused at the focal point FP.

(3-1-3) Third Example of Generation of Control Parameters A third example of generation of control parameters of the present embodiment will be described.

The ultrasonic controller 10 generates a control parameter by a combination of the first example and the second example of the generation of the control parameter. That is, the ultrasonic controller 10 has focal coordinates (xfp, yfp, zfp), control point coordinates (xcp (m), ycp (m), zcp (m)), and coordinates (xtr) stored in the storage device 11. Using (n + 1), ytr (n + 1), ztr (n + 1)) and the control point sound pressure SPcp (m), the oscillation time difference ΔT (n + 1) and the oscillation amplitude difference of each ultrasonic transducer TR (n + 1). Calculate ΔA (n + 1).

By individually controlling the combination of the oscillation phase and the oscillation amplitude of the plurality of ultrasonic transducers TR, the oscillation phase difference and the oscillation amplitude difference are given to the ultrasonic waves radiated from each ultrasonic transducer TR. The focal position and the number of focal points depend on the combination of the oscillation phase difference and the oscillation amplitude difference. That is, the ultrasonic speaker 21 can change the focal position and the number of focal points by controlling the combination of the oscillation phase difference and the oscillation amplitude difference.

(3-1-4) Summary of generation of control parameters As described above, the processor 12 calculates at least one of the oscillation time difference ΔT and the oscillation amplitude difference ΔA of each ultrasonic vibrator TR. The processor 12 supplies a drive signal to each ultrasonic vibrator TR according to at least one of the oscillation time difference ΔT and the oscillation amplitude difference ΔA.
When each ultrasonic vibrator TR oscillates with a time difference corresponding to this drive signal, the ultrasonic waves radiated from each ultrasonic vibrator TR have an oscillation phase difference according to the oscillation time difference ΔT, and thus are focused by the focal point FP. do.
When each ultrasonic vibrator TR oscillates with an oscillation amplitude corresponding to this drive signal, the ultrasonic waves radiated from each ultrasonic vibrator TR have an oscillation amplitude difference ΔA and are therefore focused by the focal point FP.
The ultrasonic waves focused at the focal point FP form a sound source. An audible sound is generated from this sound source. That is, the ultrasonic speaker 21 can form an audible sound source at an arbitrary position in space.

As the number of control points CP (m) increases, the size of the focal point FP becomes smaller (that is, a more local focal point FP is formed). As the size of the focal FP becomes smaller, the region where the audible sound from the sound source formed in the focal FP can be heard becomes smaller. As a result, a sound source of audible sound that can be heard in a region close to the focal FP but cannot be heard in a region far from the focal FP can be formed in an arbitrary focal FP in space.

The distribution of the audible range in which the listener L can hear the audible sound is defined by the combination of the focal coordinates (xfp, yfp, zfp) and the control point coordinates (xcp (m), ycp (m), zcp (m)).
Therefore, the processor 12 can change the audible range by adjusting at least one of the oscillation phase difference and the oscillation amplitude difference of the ultrasonic waves.

(3-2) Operation Example of Ultrasonic Speaker An operation example of the ultrasonic speaker 21 of the present embodiment will be described.

(3-2-1) Operation example 1 (single focus)
The operation example 1 of the ultrasonic speaker 21 of this embodiment will be described. FIG. 8 is an explanatory diagram of an operation example 1 of the ultrasonic speaker of the present embodiment. FIG. 9 is a diagram showing a sound source formed in the operation example 1 of FIG. In operation example 1, ultrasonic waves are focused on one focal point.

As shown in FIG. 8, the ultrasonic speaker 21 of the operation example 1 radiates an ultrasonic wave USW1 having at least one of an oscillation phase difference and an oscillation amplitude difference. The ultrasonic wave USW1 is focused at the focal length FP1 which is separated from the center of the vibrator array FA by the focal length d1.

As shown in FIG. 9, the ultrasonic speaker 21 forms a point sound source SS1 at the focal point FP1 and forms a control region CA composed of control points CP (m) around the point sound source SS1.
For example, when the focal point FP1 is located near the ear of the listener L, the point sound source SS1 is formed near the ear of the listener L, and the control region CA is formed around the ear of the listener L. In the control area CA, the sound pressure of ultrasonic waves weakens and meets.
In this case, the listener L can hear the audible sound from the point sound source SS1 without being affected by the sound pressure of the ultrasonic waves in the control region CA.
Further, the size of the point sound source SS1 can be suppressed (that is, the point sound source SS1 is formed only in a limited range).

(3-2-2) Operation example 2 (double focus)
The operation example 2 of the ultrasonic speaker 21 of this embodiment will be described. FIG. 10 is an explanatory diagram of operation example 2 of the ultrasonic speaker of the present embodiment. FIG. 11 is a diagram showing a sound source formed in the operation example 2 of FIG. In operation example 2, the ultrasonic waves are focused on a plurality of focal points.

As shown in FIG. 10, ultrasonic waves USW2a and USW2b having an oscillation phase difference according to the time difference of vibration are radiated from the ultrasonic speaker 21 of the operation example 2.
The ultrasonic wave USW2a is focused at the focal length FP2a which is separated from the center of the vibrator array FA by the focal length d2a.
The ultrasonic wave USW2b is focused at the focal length FP2b separated by the focal length d2b from the center of the vibrator array FA.

As shown in FIG. 11, the ultrasonic speaker 21 forms the point sound sources SS2a and SS2b at the focal points FP2a and FP2b, respectively, and forms the control regions CAa and CAb around the point sound sources SS2a and SS2b, respectively.
For example, when the focal point FP2a is located near the ear of the listener L1, the point sound source SS2a is formed at the ear of the listener L1, and the control region CAa is formed around the ear of the listener L1. In the control region CAa, the sound pressures of ultrasonic waves focused on the focal point FP2a weaken each other.
When the focal point FP2b is located near the ear of the listener L2, the point sound source SS2b is formed at the ear of the listener L2, and the control region CAb is formed at the peripherally weakening side of the ear of the listener L2. In the control region CAb, the sound pressures of ultrasonic waves focused on the focal point FP2b weaken each other.
In this case, the listener L1 can hear the audible sound from the point sound source SS2a without being affected by the sound pressure of the ultrasonic waves in the control regions CAa and CAb. On the other hand, the listener L2 can hear the audible sound from the point sound source SS2b without being affected by the sound pressure of the ultrasonic waves in the control regions CAa and CAb.
Further, the sizes of the point sound sources SS2a and SS2b can be suppressed (that is, the point sound sources SS2a and SS2b are formed only in a limited range).

The ultrasonic speaker 21 can also form point sound sources at three or more focal points. In this case, a control area is formed around each focal point.

(4) Control of Audio System The control of the audio system of the present embodiment will be described. FIG. 12 is a flowchart of the control process of the audio system of the present embodiment. FIG. 13 is a schematic diagram of the sound pressure information and the first surround pan parameter referred to in the process of FIG. FIG. 14 is a schematic diagram of sound pressure information divided into a first frequency band to a third frequency band in the process of FIG. FIG. 15 is a schematic diagram of the second surround pan parameter generated in the process of FIG.

After step S200, the sound source 23 executes the output of the audio signal (S200).
Specifically, the sound source 23 encodes the audio signal and outputs it to the ultrasonic controller 10.
The audio signal includes sound pressure information of the sound to be reproduced (FIG. 13A) and a first surround pan parameter (FIG. 13B).

FIG. 13A is an example of sound pressure information. The horizontal axis is frequency (Hz) and the vertical axis is sound pressure (dB).

FIG. 13B is an example of the first surround pan parameter in the 5.1ch surround mode. The first surround pan parameters are the sound pressure of the center speaker (C), the right front speaker (R), the left front speaker (L), the right surround speaker (RS), the left surround speaker (LS), and the woofer (LFE). Indicates the balance (that is, panning) of.

The ultrasonic controller 10 executes acquisition of usage environment information (S100).

Specifically, the processor 12 generates layout information indicating the layout of the usage environment SP. The layout information includes information indicating the three-dimensional size of the usage environment SP and information indicating the three-dimensional shape.
As an example, the camera 24 captures image information of the usage environment SP. The processor 12 applies three-dimensional modeling to the image information captured by the camera 24 to generate layout information indicating the layout of the usage environment SP and stores it in the storage device 11.
As another example, the processor 12 stores the layout information (for example, three-dimensional CAD data) of the usage environment SP in the storage device 11 via the input / output interface 13 or the communication interface 14.

The position detection unit 25 detects the position of a person by irradiating infrared rays and receiving reflected light of infrared rays.
The processor 12 identifies the relative position by generating three-dimensional coordinates indicating the relative position of the listener L with respect to the ultrasonic speaker 21 based on the electric signal generated by the position detection unit 25.

After steps S100 and S200, the ultrasonic controller 10 executes an audio signal input (S101).
Specifically, the processor 12 inputs the audio signal output from the sound source 23 in step S200.

After step S101, the ultrasonic controller 10 executes decoding (S102) of the audio signal.
Specifically, the processor 12 extracts the sound pressure information (FIG. 13A) and the first surround pan parameter (FIG. 13B) from the audio signal by decoding the audio signal.
The processor 12 stores the sound pressure information and the first surround pan parameter in the storage device 11.

After step S102, the ultrasonic controller 10 executes the determination of the focal position and the control point position (S103).

As a first example, when one listener L is detected by the position detection unit 25 in step S100, the processor 12 determines the listener L with respect to the ultrasonic speaker 21 based on the detection result of the position detection unit 25 in step S100. Identify the relative position.
The processor 12 determines the positions of the focal point FP1 and the control point CP (m) in FIG. 9 based on the specified relative positions.

As a second example, when a plurality of (for example, two) listeners L1 and U2 are detected by the position detection unit 25 in step S100, the processor 12 superimposes based on the detection result of the position detection unit 25 in step S100. The relative position of the listener L with respect to the sound wave speaker 21 is specified.
The processor 12 determines the positions of the plurality of focal points FP2a and FP2b in FIG. 11 and the control point CP (m) based on the specified relative positions.

As a third example, in step S100, when the user inputs a user instruction for designating the focus position via the input / output interface 13, the processor 12 bases the user instruction on the focus FP1 of FIG. And the position of the control point CP (m) is determined.

After step S103, the ultrasonic controller 10 executes the generation of the second surround pan parameter (S104).
Specifically, the processor 12 divides the frequency characteristics of the sound wave level information stored in the storage device 11 in step S102 into the first frequency band B1 to the third frequency band B3 (FIG. 14).

As shown in FIG. 14, the first frequency band B1 is a frequency band having a first frequency threshold value of TH1 or higher.
The processor 12 determines the first frequency band B1 based on the output characteristics of the ultrasonic speaker 21.
The processor 12 determines the sound pressure of the ultrasonic speaker 21 so that the sound pressure of the ultrasonic speaker 21 is the highest and the sound pressure of the woofer 26 is the lowest with respect to the frequency components constituting the first frequency band B1. , The sound pressure of the loud speaker 22 and the sound pressure of the woofer 26 are determined.

The second frequency band B2 is a frequency band between the second frequency threshold TH2 and the first frequency threshold TH1.
The processor 12 determines the second frequency band B2 based on the output characteristics of the loudspeaker 22.
The processor 12 uses the sound pressure of the ultrasonic speaker 21 and the sound pressure of the ultrasonic speaker 21 so that the sound pressure of the loudspeaker 22 is the highest and the sound pressure of the woofer 26 is the lowest with respect to the frequency components constituting the second frequency band B2. The sound pressure of the loud speaker 22 and the sound pressure of the woofer 26 are determined.

The third frequency band B3 is a frequency band equal to or lower than the second frequency threshold value TH2.
The processor 12 determines the third frequency band B3 based on the output characteristics of the woofer 26.
The processor 12 sets the sound pressure of the ultrasonic speaker 21 so that the sound pressure of the woofer 26 is the highest and the sound pressure of the ultrasonic speaker 21 is the lowest with respect to the frequency components constituting the third frequency band B3. , The sound pressure of the loud speaker 22 and the sound pressure of the woofer 26 are determined.

The processor 12 generates a second surround pan parameter (FIG. 15) based on the determined sound pressure (sound pressure of the ultrasonic speaker 21, sound pressure of the loudspeaker 22, and sound pressure of the woofer 26).
The second surround pan parameters in FIG. 15 are an ultrasonic speaker (US), a right front speaker (R), a left front speaker (L), a right surround speaker (RS), a left surround speaker (LS), and a woofer (LFE). ) Shows the balance of sound pressure (that is, the panning of the speaker component including the ultrasonic speaker 21).

FIG. 15A shows an example of the second surround pan parameter when the sound pressure in the first frequency band B1 is higher than the sound pressure in the second frequency band B2.
As shown in FIG. 15A, in the second surround pan parameter when the sound pressure in the first frequency band B1 is higher than the sound pressure in the second frequency band B2, the loudspeaker 22 (right front speaker (R), left front speaker (R), left front speaker (R) The sound pressure of the ultrasonic speaker (US) is higher than the sound pressure of the right surround speaker (RS) and the left surround speaker (LS)).
That is, when the sound pressure in the first frequency band B1 is higher than the sound pressure in the second frequency band B2, the ultrasonic controller 10 emphasizes the sound of the ultrasonic speaker 21 rather than the sound of the loud speaker 22.

FIG. 15B shows an example of the second surround pan parameter when the sound pressure in the first frequency band B1 is lower than the sound pressure in the second frequency band B2.
As shown in FIG. 15A, in the second surround pan parameter when the sound pressure in the first frequency band B1 is lower than the sound pressure in the second frequency band B2, the loudspeaker 22 (right front speaker (R), left front speaker (R), left front speaker (R) The sound pressure of the ultrasonic speaker (US) is lower than the sound pressure of the right surround speaker (RS) and the left surround speaker (LS)).
That is, when the sound pressure in the first frequency band B1 is lower than the sound pressure in the second frequency band B2, the ultrasonic controller 10 emphasizes the sound of the loud speaker 22 more than the sound of the ultrasonic speaker 21.

After step S104, the ultrasonic controller 10 executes the modulation level determination (S105).
Specifically, the processor 12 modulates based on the sound pressure of the ultrasonic speaker (US) among the second surround pan parameters determined in step S104, and the focal position and control point position determined in step S103. The level (for example, the AM modulation level of the ultrasonic wave emitted from the ultrasonic speaker 21) is determined.

After step S105, the ultrasonic controller 10 executes the acoustic hologram calculation (S106).

In the first example of step S106, the processor 12 distributes the oscillation phase difference corresponding to the phase distribution for forming the focal point FP and the control point CP at the focal position and the control point position determined in step S103, respectively (hereinafter, Perform an acoustic hologram calculation to obtain (referred to as "phase difference distribution").
The processor 12 determines the oscillation timing of each ultrasonic vibrator TR (n) based on the phase difference distribution obtained by the acoustic hologram calculation.

In the second example of step S106, the processor 12 executes an acoustic hologram calculation for obtaining an amplitude distribution for forming the focal point FP and the control point CP at the focal position and the control point position determined in step S103, respectively. ..
The processor 12 determines the oscillation amplitude of each ultrasonic vibrator TR (n) based on the amplitude distribution obtained by the acoustic hologram calculation.

After step S105, the ultrasonic controller 10 executes the generation of the speaker control signal (S107).

Specifically, the processor 12 includes the sound pressure of the ultrasonic speaker (US), at least one of the oscillation phase difference and the oscillation amplitude determined in step S106, and the modulation determined in step S105 among the second surround pan parameters. Based on the level and, a first speaker control signal (an example of "control parameter") for controlling the ultrasonic speaker 21 is generated.

The processor 12 determines the sound pressure of the right front speaker (R), the left front speaker (L), the right surround speaker (RS), and the left surround speaker (LS) among the second surround pan parameters determined in step S104. Based on this, a second speaker control signal for controlling the loudspeaker 22 is generated.

The processor 12 generates a third speaker control signal for controlling the woofer 26 based on the sound pressure of the woofer (LFE) among the second surround pan parameters.

The processor 12 outputs the first speaker control signal to the third speaker control signal to the ultrasonic speaker 21, the loudspeaker 22, and the woofer 26, respectively.
The ultrasonic speaker 21 emits ultrasonic waves based on the first speaker control signal. The ultrasonic waves radiated from the ultrasonic speaker 21 are focused at the focal point FP determined in step S103, and weaken each other at the control point CP. The focused ultrasonic waves form an audible sound source at the focal FP. That is, the sound source formed in the focal point FP generates an audible sound.
The loudspeaker 22 and the woofer 26 generate an audible sound with their own sound source based on the second speaker control signal and the third speaker control signal, respectively.

The sound source 23 repeatedly executes the process of step S200 until the reproduction is completed (S201-NO).
The ultrasonic controller 10 repeatedly executes the processes of steps S100 to S107 until the reproduction is completed (S108-NO).

As a result, the audio system 1 can construct a surround environment according to the usage environment SP, the position of a person, and the audio signal output from the sound source 23.
In particular, in the audio system 1, since the focal position, the position of the control point, the number of focal points, and the number of control points of the ultrasonic speaker 21 are variable, there are restrictions on the usage environment SP (for example, the layout of the usage environment SP, the usage environment SP). It is possible to let the speaker L hear a wider variety of sounds without receiving obstacles existing inside and the position of a person.

In general, when a control point is not formed, the longer the focal length r (n), the larger the size in the radial direction of the focal point (hereinafter referred to as “depth”), so that the depth of the point sound source formed at the focal point also increases. On the other hand, according to the present embodiment, since the sound pressure of the ultrasonic wave focused on at least one focal point is weakened by the control point, the depth of the point sound source is limited regardless of the focal length r (n). Can be done. That is, a point sound source can be formed regardless of the focal length r (n).

(5) Modification Example A modification of the present embodiment will be described.

(5-1) Modification 1
Modification 1 will be described. Modification 1 is an example in which the vibrator array FA has a curved surface shape.

The oscillator array FA of the first modification is formed on a curved array surface having a variable curvature.
An actuator (for example, a variable arm) is connected to the ultrasonic speaker 21. The actuator is configured to change the curvature of the array surface (ie, the curved surface shape). When the curvature of the array surface changes, the oscillation phase difference of the ultrasonic waves radiated from the vibrator array FA also changes.

Specifically, the first speaker control signal generated in step S107 includes a drive signal for driving the actuator.
The actuator changes the curvature of the array surface based on the drive signal.

According to the first modification, the same effect as that of the present embodiment can be obtained even when the ultrasonic speaker 21 that gives an oscillation phase difference to the ultrasonic waves by changing the curvature of the array surface is used.
In particular, when the ultrasonic waves are focused on a single focal point (for example, the focal point FP1 in FIG. 8), the radiation directions of the plurality of ultrasonic vibrators TR are directed to the focal point, so that the sound pressure of the ultrasonic waves focused at the focal point is directed. Can be raised.

(5-2) Modification 2
Modification 2 will be described. Modification 2 is an example of constructing a surround environment using a plurality of ultrasonic speakers 21.

The audio system 1 of the second modification includes a plurality of ultrasonic speakers 21.

In steps S103 and S104, the processor 12 individually determines the focal position, the position of the control point, and the sound pressure of the plurality of ultrasonic speakers 21 based on the relative positions of the ultrasonic speakers 21 and the listener L.

According to the second modification, since the ultrasonic waves focused at the focal point FP increase as compared with the present embodiment, the sound pressure of the audible sound from the sound source formed by the focused ultrasonic waves can be increased. Further, even if the ultrasonic waves focused by the focal FP increase, the region where the audible sound is generated can be narrowed down by forming the control region CA around the focal FP. As a result, a more diverse surround environment can be constructed.

(5-3) Modification 3
Modification 3 will be described. Modification 3 is an example of dynamically changing the audible range.

In the first example of the third modification, the storage device 11 stores an algorithm in which the relationship between the volume of the reproduced sound and the range of the control point region with reference to the focal point is defined.
When the processor 12 receives an instruction (for example, an operation for changing the volume) of the operator (for example, the listener L) of the audio system 1, the processor 12 refers to the algorithm stored in the storage device 11 and refers to each ultrasonic oscillator. At least one of the oscillation amplitude A (n) and the oscillation phase P (n) of the ultrasonic wave radiated from TR (n) is changed.
In this case, the operator can arbitrarily change the audible range of the sound from the ultrasonic speaker 21.

In the second example of the third modification, the processor 12 has the oscillation phase P (n) or the oscillation amplitude A (n) of each ultrasonic vibrator TR (n) according to the position of the person detected by the position detection unit 25. ) Is changed. For example, when the position detection unit 25 detects the position of a specific listener L, the processor 12 calculates the control point coordinates so that the positions of the listener L other than the specific listener L are excluded from the audible range.
In this case, only a specific listener L can hear the sound from the ultrasonic speaker 21.

In the third example of the third modification, the storage device 11 stores an algorithm in which the relationship between the volume of the environmental sound and the range of the control point region with reference to the focal point is defined.
The ultrasonic controller 10 includes a sensor (not shown) that detects the volume of environmental sounds. The processor 12 has the oscillation amplitude A (n) and the oscillation phase P (n) of each ultrasonic vibrator TR (n) so that the audible range is uniformly maintained according to the volume detected by the sensor. Determine at least one.
In this case, the audible range can be maintained even if the environmental sound changes.

In the fourth example of the third modification, the ultrasonic controller 10 has an oscillation amplitude A (n) and an oscillation phase P (n) of each ultrasonic vibrator TR (n) according to the audio signal given from the sound source 23. Determine at least one of. For example, when the first surround pan parameter included in the audio signal indicates a surround pan suitable for a wide audible range, the processor 12 sets the oscillation amplitude A (n) and the oscillation phase P (n) so as to widen the audible range. decide. When the first surround pan parameter indicates a surround pan suitable for a narrow audible range, the processor 12 determines the oscillation amplitude A (n) and the oscillation phase P (n) so that the audible range is narrowed.
In this case, the audible range can be changed according to the sound to be reproduced.

According to the third modification, the audible range can be dynamically changed according to an external factor of the ultrasonic speaker 21.

(5-4) Modification 4
A modification 4 will be described. Modification 4 is an example in which ultrasonic waves are focused on the focal point FP without causing an oscillation time difference of each ultrasonic vibrator TR (n).

The processor 12 calculates the oscillation amplitude difference ΔA (n + 1) between the oscillation amplitude A (n + 1) of the ultrasonic transducer TR (n + 1) and the oscillation amplitude A (n) of the ultrasonic transducer TR (n) in Equation 4. Use to calculate. As shown in Equation 4, the oscillation amplitude difference ΔA is a function of the focal length and the speed of sound.
ΔA (n + 1) = h (r (n + 1), c) ... (Equation 4)
・ C: Speed of sound ・ Focal length: r (n + 1)

As described above, the processor 12 uses the focal coordinates (xfp, yfp, zfp) and the coordinates (xtr (n + 1), ytr (n + 1), ztr (n + 1)) stored in the storage device 11, respectively. The oscillation amplitude difference ΔA (n + 1) of the ultrasonic transducer TR (n + 1) is calculated. The processor 12 supplies a drive signal to each ultrasonic vibrator TR (n + 1) according to the oscillation amplitude difference ΔA (n + 1).

Each ultrasonic vibrator TR oscillates at the same time in response to this drive signal. Since the ultrasonic waves radiated from each ultrasonic vibrator TR have an oscillation amplitude difference ΔA, they are focused at the focal point FP.

According to the change example 4, the ultrasonic waves can be focused on the focal point FP without generating the oscillation time difference ΔT of each ultrasonic vibrator TR.

(5-5) Modification 5
A modified example 5 will be described. Modification 5 controls the phase difference between the sound pressure distribution of ultrasonic waves focused on the focal point FP and the sound pressure distribution of ultrasonic waves at each control point CP (m) (hereinafter referred to as “control point phase difference”). This is an example of FIG. 16 is an explanatory diagram of the action and effect of the modified example 5.

In the modified example 5, the control point coordinates (xcp (m), ycp (m), zcp (m) are determined in consideration of the following conditions. The priority of the following conditions is the application of the ultrasonic speaker 21. Dependent.
(Condition 1) The change in the sound pressure distribution of the focal FP (specifically, the shape of the main lobe of ultrasonic waves focused on the focal FP) due to the control point FP is below a certain level.
(Condition 2) The change in the sound pressure of the focal FP (specifically, the peak value of the main lobe of the ultrasonic waves focused on the focal FP) due to the control point FP is below a certain level.
(Condition 3) The sound pressure of the control point FP is smaller than the sound pressure of the focal FP (specifically, the peak value of the main lobe of ultrasonic waves focused on the focal FP).

The ultrasonic controller 10 of the modification 5 determines the control point coordinates (xcp (m), ycp (m), zcp (m) that satisfy the above conditions 1 to 3.

In the first example of the modified example 5, the processor 12 has the control point coordinates (xcp (m), ycp (m), zcp (m)) and the control point sound as in the first example of generating the control parameter. In addition to the pressure SPcp (m), the control point phase difference ΔSPcp (m) is determined. The control point phase difference ΔSPcp (m) is the phase of ultrasonic waves focused on the focal point FP (hereinafter referred to as “focus phase”) Pfp and the phase of the control point CP (m) (hereinafter referred to as “control point phase”) Pcp (hereinafter referred to as “control point phase”). This is the difference from m).

The processor 12 calculates the oscillation time difference ΔT (n + 1) by using a function of the focal coordinate and the control point coordinate (for example, Equation 5). As shown in Equation 5, the oscillation time difference ΔT is, for example, a function of the focal length, the control point distance, the control point phase difference, and the speed of sound.
ΔT (n + 1) = f (r (n + 1), q (n + 1), ΔSPcp (m), c) ... (Equation 5)
・ C: Speed of sound ・ Focal length: r (n + 1)
・ Control point distance: q (n + 1)
・ Control point phase difference: ΔSPcp (m)

In the second example of the modified example 5, the processor 12 has the control point coordinates (xcp (m), ycp (m), zcp (m)) and the control point sound as in the first example of generating the control parameter. In addition to the pressure SPcp (m), the control point amplitude difference ΔAcp (m) is determined. The control point amplitude difference ΔAcp (m) is the amplitude of ultrasonic waves focused on the focal point FP (hereinafter referred to as “focus amplitude”) Afp and the amplitude of the control point CP (m) (hereinafter referred to as “control point amplitude”) Acp (hereinafter referred to as “control point amplitude”). This is the difference from m).

The processor 12 calculates the oscillation amplitude difference ΔA (n + 1) using the equation 7. As shown in Equation 7, the oscillation amplitude difference ΔA is a function of the focal length, the control point distance, the control point sound pressure SPcp (m), the control point amplitude difference ΔAcp (m), and the speed of sound.
ΔA (n + 1) = g (r (n + 1), q (n + 1), SPcp (m), ΔAcp (m), c) ... (Equation 7)
・ C: Speed of sound ・ Focal length: r (n + 1)
・ Control point distance: q (n + 1)
・ Control point sound pressure: SPcp (m)
・ Control point amplitude difference: ΔAcp (m)

The horizontal axis of FIG. 16 is the Y coordinate, and the vertical axis is the sound pressure. The solid line is the sound pressure distribution of the ultrasonic waves focused on the focal point FP when the control point CP is not set. The broken line is the sound pressure distribution of the ultrasonic waves focused on the focal point FP when the control point CP is set.
The control point CP is set at a position (Y = ycp) shifted by a predetermined distance from the focal point FP (Y = yfp) in step S103.
As shown in FIG. 16, when the control point CP is not set, the sound pressure distribution is gently attenuated in the region of Y> yfp.
On the other hand, when the control point CP is set so that the sound pressure becomes zero at the position of Y = ycp, the attenuation of the sound pressure distribution becomes steep in the region of Y> Yfp.
In other words, the sound pressure distribution when the control point CP is set is the length in the ultrasonic radiation direction (Y direction) with respect to the focal point FP, as compared with the sound pressure distribution when the control point CP is not set. (That is, the depth of the focal point FP) becomes shorter. As a result, the sound pressure distribution MLfp1 of the focal point FP when the control point CP is set is localized from the sound pressure distribution MLfp0 of the focal point FP when the control point CP is not set.

As described above, according to the modification 5, the control point coordinates (xcp (m), ycp (m), zcp (m) are determined so as to satisfy the conditions 1 to 3, which is a condition. It is synonymous with controlling the control point phase difference so as to meet the conditions 1 to 3. As a result, the sound pressure distribution MLfp1 localized near the focal point FP can be formed, and the control point CP can be formed. The effect caused by the setting of can be minimized.

(6) Summary of the present embodiment A summary of the present embodiment will be given.

The first aspect of this embodiment is
An ultrasonic controller 10 that controls an ultrasonic transducer array FA having a plurality of ultrasonic transducers TR (n) that emit ultrasonic waves that focus on at least one focal point at an arbitrary position in space.
A means for calculating the focal coordinates of the focal point and the control point coordinates of at least one control point (for example, the processor 12 that executes the process of step S103) is provided.
The sound pressure SPcp at the control point is lower than the sound pressure SPfp at the focal point.
A means (for example, a processor 12 that executes the process of step S107) for generating control parameters for controlling each ultrasonic vibrator TR (n) based on the focal coordinates and the control point coordinates is provided.
The control point is the point where the sound pressure of the ultrasonic wave is lower than the sound pressure of the ultrasonic wave focused on the focal point.
Means for individually controlling each ultrasonic vibrator TR (n) so as to emit ultrasonic waves focused on the focal point based on the control parameters of each ultrasonic vibrator TR (n) (for example, the process of step S107). An ultrasonic controller 10 comprising a processor 12) that executes the above.

According to the first aspect, the sound pressures of ultrasonic waves focused on the focal point in the control point region weaken each other. This makes it possible to control the ultrasonic distribution around the focal point.
As a result, the listener L can hear the audible sound from the point sound source without being affected by the sound pressure of the ultrasonic wave in the control region.
In addition, the size of the point sound source can be suppressed (that is, the point sound source is formed only in the intended region).

The second aspect of this embodiment is
The generating means generates control parameters so that the ultrasonic waves radiated from each ultrasonic vibrator TR (n) are weakened at the control point.
The ultrasonic controller 10.

The third aspect of this embodiment is
The means of calculation is to calculate the focal coordinates and control point coordinates based on the position of the person.
The ultrasonic controller 10.

According to the third aspect, it is possible to form a point sound source according to the position of a person (for example, a listener).

The fourth aspect of this embodiment is
The control parameter includes at least one of oscillation amplitude and oscillation phase.
The ultrasonic controller 10.

A fifth aspect of this embodiment is
The means for controlling is the ultrasonic controller 10 that generates the oscillation phase difference of the ultrasonic waves radiated by the ultrasonic vibrator array FA by individually controlling the oscillation timings of the plurality of ultrasonic vibrators TR (n). be.

According to the fifth aspect, in order to form a point sound source, it is possible to use up to the upper limit of the sound pressure of each ultrasonic vibrator TR (n).

The sixth aspect of this embodiment is
The control means generates an oscillation phase difference of ultrasonic waves radiated by the vibrator array FA by changing the curvature of the array surface of the vibrator array FA composed of a plurality of ultrasonic vibrators TR (n).
The ultrasonic controller 10.

According to the sixth aspect, even when the oscillator array FA has a curved surface, the same effect as that of the first aspect can be obtained.

The seventh aspect of this embodiment is
A means for acquiring usage environment information regarding the usage environment (for example, a processor 12 that executes the process of step S100) is provided.
The means for calculation is the ultrasonic controller 10 that calculates the focal coordinates and the control point coordinates with reference to the usage environment information.

According to the seventh aspect, it is possible to form a point sound source according to the usage environment.

The eighth aspect of this embodiment is
An ultrasonic speaker 21 that can be connected to the ultrasonic controller 10 according to any one of the above.
Equipped with a plurality of ultrasonic transducers TR (n)
The ultrasonic speaker 21 includes a drive unit that individually drives a plurality of ultrasonic vibrators TR (n) under the control of the ultrasonic controller 10.

The ninth aspect of this embodiment is
It is a program for making a computer (for example, a processor 12) function as each means described in any of the above.

(7) Other Modification Examples Other modification examples will be described.

The storage device 11 may be connected to the ultrasonic controller 10 via the network NW.

The speaker component of FIG. 2 (combination of the ultrasonic speaker 21, the loudspeaker 22, and the woofer 26) is an example. This embodiment is also applicable to the following speaker components.
-Speaker 21 alone (that is, a speaker component that does not include speakers other than the ultrasonic speaker 21 (loud speaker 22 and woofer 26 in FIG. 2))-Speaker that includes a speaker (for example, a subwoofer) not shown in FIG. component

The camera 24 may detect the relative position of the listener L instead of the position detection unit 25.
For example, the camera 24 acquires the image information of the listener L.
The processor 12 applies a feature amount analysis based on a human feature amount to the image information acquired by the camera 24. As a result, the position of a person (position on the image space) in the image information is specified.
The processor 12 specifies the relative position by generating three-dimensional coordinates indicating the relative position of the listener L with respect to the ultrasonic speaker 21 based on the position on the specified image space.

The ultrasonic speaker 21 may detect the relative position of the listener L instead of the position detection unit 25.
For example, an ultrasonic sensor for detecting a reflected wave of ultrasonic waves emitted by an ultrasonic vibrator TR is provided.
In step S100, the processor 12 emits ultrasonic waves by driving the ultrasonic vibrator TR. The ultrasonic waves are reflected by the listener L.
The ultrasonic sensor detects the reflected wave from the listener L.
The processor 12 estimates the relative position of the listener L based on the time from when the ultrasonic wave is emitted until the reflected wave is detected by the ultrasonic sensor.

In the operation example of the ultrasonic speaker 21, an example in which the ultrasonic vibrator TR (n) vibrates with a time difference is shown, but the present embodiment is not limited to this. The ultrasonic speaker 21 is similarly applicable when the ultrasonic vibrator TR (n) vibrates at the same time with different oscillation amplitudes, and when the ultrasonic vibrator TR (n) vibrates with a time difference and different oscillation amplitudes.

The control point CP is at least one of a null point at which the sound pressure of the ultrasonic wave becomes zero and a point at which the sound pressure of the ultrasonic wave is lower than that of the ultrasonic wave focused on the focal point FP.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited to the above embodiments. Further, the above-described embodiment can be improved or modified in various ways without departing from the spirit of the present invention. Moreover, the above-described embodiment and modification can be combined.

1 Audio system 10 Ultrasonic controller 11 Storage device 12 Processor 13 Input / output interface 14 Communication interface 21 Ultrasonic speaker 21a Cover 21b Housing 22 Loud speaker 23 Sound source 24 Camera 25 Position detector 26 Woofer

Claims (9)

An ultrasonic controller that controls an ultrasonic transducer array having a plurality of ultrasonic transducers that emit ultrasonic waves focused on at least one focal point at an arbitrary position in space.
A means for calculating the focal coordinates of the focal point and the control point coordinates of at least one control point is provided.
The sound pressure at the control point is lower than the sound pressure at the focal point.
A means for generating control parameters for controlling each ultrasonic vibrator based on the focal coordinates and the control point coordinates is provided.
A means for individually controlling each ultrasonic vibrator so as to radiate an ultrasonic wave focused on the focal point based on the control parameters of each ultrasonic vibrator is provided.
Ultrasonic controller. The generating means generates the control parameters so that the ultrasonic waves radiated from the ultrasonic transducers weaken each other at the control point.
The ultrasonic controller according to claim 1. The calculating means calculates the focal coordinates and the control point coordinates based on the position of a person.
The ultrasonic controller according to claim 1 or 2. The control parameter includes at least one of oscillation amplitude and oscillation phase.
The ultrasonic controller according to any one of claims 1 to 3. The controlling means individually controls the oscillation timings of the plurality of ultrasonic vibrators to generate an oscillation phase difference of the ultrasonic waves radiated by the ultrasonic vibrator array.
The ultrasonic controller according to any one of claims 1 to 4. The controlling means generates an oscillation phase difference of ultrasonic waves radiated by the ultrasonic vibrator array by changing the curvature of the array surface of the vibrator array composed of a plurality of ultrasonic vibrators.
The ultrasonic controller according to any one of claims 1 to 5. Equipped with a means to obtain usage environment information regarding the usage environment
The calculation means further refers to the usage environment information and calculates the focal coordinates and the control point coordinates.
The ultrasonic controller according to any one of claims 1 to 6. An ultrasonic speaker that can be connected to the ultrasonic controller according to any one of claims 1 to 7.
Equipped with multiple ultrasonic transducers
An ultrasonic speaker including a drive unit that individually drives the plurality of ultrasonic vibrators under the control of the ultrasonic controller. A program for operating a computer as each means according to any one of claims 1 to 7.

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