JP2013165329A - Oscillation apparatus and oscillation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minutely control a region in which an audible sound is demodulated, in a parametric speaker.SOLUTION: A speaker array 10 has a constitution in which plural oscillators 100 are arranged in an array (two-dimensionally), where the oscillators 100 may be arranged linearly. A controller 20 inputs an oscillation signal to each of the oscillators 100 to cause each of the oscillators 100 to output acoustic waves. The oscillation signal is a modulation signal for a parametric speaker or a carrier signal with the same frequency as the modulation signal. The controller 20 selects between the modulation signal and the carrier signal to input to at least one of the oscillators 100, or to input neither signal.

Description

  The present invention relates to an oscillation device and an oscillation method that function as a parametric speaker.

  One of the speakers is a parametric speaker. For example, as described in Patent Document 1, the parametric speaker modulates an audio signal into a modulation signal in an ultrasonic band, and demodulates the modulation signal into an audible sound in the atmosphere.

JP-A-4-123699

  The characteristic of the parametric speaker is that it has high directivity. However, it has been difficult to finely control the region where the audible sound is demodulated.

  An object of the present invention is to provide an oscillation device and an oscillation method that function as a parametric speaker and can finely control a region where audible sound is demodulated.

According to the present invention, a plurality of vibrators arranged side by side;
Control means for inputting an oscillation signal to the plurality of vibrators to oscillate;
With
The control means includes
Either a modulation signal for a parametric speaker or a carrier signal having the same frequency as the modulation signal is input as the oscillation signal to the plurality of vibrators.
An oscillation device is provided that switches whether at least one of the modulation signal and the carrier signal is input to the at least one vibrator, or which signal is not input.

According to the present invention, a parametric speaker modulation signal or a carrier signal having the same frequency as the modulation signal is input to a plurality of vibrators arranged side by side,
An oscillation method for controlling an audible sound generation area by switching whether at least one of the modulation signal and the carrier signal is input or not input to at least one of the vibrators. Provided.

  According to the present invention, it is possible to finely control a region where an audible sound is demodulated in a parametric speaker.

It is a figure which shows the structure of the oscillation apparatus which concerns on 1st Embodiment. It is a figure for demonstrating that the oscillation apparatus shown in FIG. 1 can control an audible sound generation | occurrence | production area. It is a figure for demonstrating that the oscillation apparatus shown in FIG. 1 can control an audible sound generation | occurrence | production area. It is a figure for demonstrating that the oscillation apparatus shown in FIG. 1 can control an audible sound generation | occurrence | production area. It is a figure for demonstrating that the oscillation apparatus shown in FIG. 1 can control an audible sound generation | occurrence | production area. It is a figure for demonstrating that the oscillation apparatus shown in FIG. 1 can control an audible sound generation | occurrence | production area. It is a figure for demonstrating that the oscillation apparatus shown in FIG. 1 can control an audible sound generation | occurrence | production area. It is sectional drawing which shows an example of a structure of the vibrator | oscillator which concerns on 2nd Embodiment. It is a figure which shows an example of a structure of the control part which concerns on 2nd Embodiment. It is a figure which shows the structure of the oscillation apparatus which concerns on 3rd Embodiment.

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

(First embodiment)
FIG. 1 is a diagram illustrating the configuration of the oscillation device according to the first embodiment. This oscillation device is used as a parametric speaker. Specifically, the oscillation device is used as a sound source of an electronic device (for example, a mobile phone, a laptop personal computer, a small game device, etc.).

  This oscillation device includes a speaker array 10 and a control unit 20. The speaker array 10 has a configuration in which a plurality of transducers 100 are arranged in an array (two-dimensional). However, the plurality of vibrators 100 may be arranged one-dimensionally. The control unit 20 inputs an oscillation signal to each of the plurality of transducers 100 and outputs sound waves from each of the plurality of transducers 100. The oscillation signal is either a modulation signal for a parametric speaker or a carrier signal having the same frequency as the modulation signal. Then, the control unit 20 switches whether at least one of the modulation signal and the carrier signal is input to the at least one vibrator 100 or not. As a result, as will be described in detail later, it is possible to finely control a region where the audible sound is demodulated (an audible sound generation area 30 described later).

  The control unit 20 generates a modulation signal for a parametric speaker by modulating an audio signal of an audible sound input from the outside. This modulation signal is generated, for example, by AM (Amplitude Modulation) modulation, DSB (Double Side Band) modulation, SSB (Single Side Band) modulation, or FM (Frequency Modulation) modulation. The control unit 20 also generates a carrier signal.

  2 to 7 are diagrams for explaining that the region in which the audible sound is demodulated can be controlled by the oscillation device shown in FIG. The parametric speaker utilizes the fact that when a sound wave of two frequencies propagates in the air, a difference frequency between the two frequencies is newly generated due to the nonlinearity of the particle velocity of the sound wave in the air. For this reason, when the oscillation device shown in FIG. 1 is functioned as a parametric speaker, a modulation signal is input to one of the vibrators 100 to generate a modulation wave, and a carrier signal is input from another vibrator 100. It is necessary to oscillate the carrier wave. Each of these modulated waves and carrier waves has directivity because the frequency has an ultrasonic region (for example, 20 kHz or more, preferably 40 kHz or more). In the region where the modulated wave and the carrier wave overlap, an audible sound appears in a region where the distance from the oscillation device is a fixed distance (denoted as a demodulatable area in the figure).

  In the present embodiment, the control unit 20 can switch whether all the modulation signals and carrier signals are input to all the transducers 100, or no signal is input.

  For example, in the example illustrated in FIG. 2, the control unit 20 causes the leftmost three of the nine vibrators 100 arranged to function as the carrier wave oscillation element 104 and the right three as the modulation signal oscillation element 102. It is functioning as. The control unit 20 inputs the same output carrier signal to any of the carrier oscillation elements 104 and also inputs the same output modulation signal to any modulation signal oscillator 102. An area where the carrier wave output from the carrier wave oscillation element 104 and the modulated wave output from the modulation signal oscillation element 102 overlap is an audible sound generation area 30.

  On the other hand, in the example shown in FIG. 3, the control unit 20 causes the leftmost four of the nine vibrators 100 arranged to function as the carrier wave oscillation element 104 and the right four for the modulation signal. It functions as the oscillation element 102. In this case, since the sound pressure of the modulated wave and the carrier wave is higher than in the example shown in FIG. 2, the width of the region where the carrier wave is transmitted (ie, the directivity angle) and the width of the region where the modulated wave is transmitted (ie, the directivity angle) ) Is narrower than the example shown in FIG. For this reason, the audible sound generation area 30 is likely to be narrower in the direction parallel to the speaker array 10 as compared to the example shown in FIG. On the other hand, the audible sound generation area 30 is wider in the distance direction from the speaker array 10 than the example shown in FIG.

  In the example shown in FIG. 4, the control unit 20 reduces the number of carrier oscillation oscillator elements 104 by one as compared with FIG. In this case, the audible sound generation area 30 is narrower in both the distance from the speaker array 10 and the direction parallel to the speaker array 10 as compared to the example shown in FIG.

  Further, in the example shown in FIG. 5, the control unit 20 shifts the vibrator 100 functioning as the modulation signal oscillation element 102 to the left as compared with FIG. 2 (that is, the carrier oscillation oscillation element 104). ). In this case, the audible sound generation area 30 is wider both in the distance from the speaker array 10 and in the direction parallel to the speaker array 10 as compared to the example shown in FIG.

  Further, the control unit 20 can control the width of the demodulatable area by controlling the amplitudes of the modulation signal and the carrier signal (that is, controlling the signal amplification factor).

  For example, the example shown in FIG. 6 shows a case where the amplitudes of the modulation signal and the carrier signal are reduced compared to the example shown in FIG. In this case, the demodulatable area becomes narrow in each of the direction approaching the speaker array 10 and the direction away from the speaker array 10.

  In the example shown in FIG. 7, the amplitude of the modulation signal and the carrier signal is increased as compared with the example shown in FIG. In this case, the demodulatable area expands in each of the directions approaching and separating from the speaker array 10.

  As described above, according to the present embodiment, the control unit 20 can switch the modulation signal and the carrier signal to be input to the at least one vibrator 100 or not to input any signal. The sound generation area can be finely controlled.

  In addition, the control unit 20 can finely control the audible sound generation area by controlling the position and number of the transducers 100 to which the modulation signal is input and the position and number of the transducers 100 to which the carrier signal is input. .

(Second Embodiment)
The present embodiment is a more specific configuration of the vibrator 100 and the control unit 20 than the first embodiment.

  FIG. 8 is a cross-sectional view illustrating an example of the configuration of the vibrator 100. The vibrator 100 according to this embodiment includes a piezoelectric element 150. The controller 20 oscillates the sound wave from the vibrator 100 by bending and vibrating the piezoelectric element 150.

  Specifically, the first vibration member 140, the piezoelectric element 150, the second vibration member 130, the elastic material 120, and the support portion 110 are included.

  The first vibrating member 140 has a sheet shape and vibrates due to vibration generated from the piezoelectric element 150. The first vibrating member 140 adjusts the basic resonance frequency of the piezoelectric element 150. The thickness of the first vibrating member 140 is preferably 5 μm or more and 500 μm or less. The first vibrating member 140 preferably has a longitudinal elastic modulus, which is an index indicating rigidity, of 1 Gpa to 500 GPa. When the rigidity of the first vibrating member 140 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 first vibrating member 140 is not particularly limited as long as it is a material having a high elastic modulus with respect to the piezoelectric element 150 that is a brittle material, such as metal or resin, but from the viewpoint of workability and cost, it is not limited. Bronze or stainless steel is preferred.

  The piezoelectric element 150 is formed of piezoelectric ceramics such as PZT, for example. However, the piezoelectric element 150 may be formed of other piezoelectric materials. The planar shape of the piezoelectric element 150 is smaller than the planar shape of the first vibrating member 140.

  The second vibrating member 130 has a sheet shape and is formed of a material having lower rigidity than the first vibrating member 140. When the first vibrating member 140 is made of metal, the second vibrating member 130 is made of resin. The planar shape of the second vibrating member 130 is larger than the planar shape of the first vibrating member 140. The edge of the second vibrating member 130 protrudes from the first vibrating member 140 over the entire circumference.

  The laminated body of the piezoelectric element 150, the first vibration member 140, and the second vibration member 130 is supported by the support portion 110 via the elastic material 120. The support part 110 is a frame-like member, and holds the laminated body of the piezoelectric element 150, the first vibration member 140, and the second vibration member 130 in the plan view. Specifically, a concave portion is formed on the inner peripheral surface of the support portion 110 over the entire circumference, and the elastic material 120 is embedded in the concave portion. The elastic material 120 is, for example, a resin. The edge of the second vibrating member 130 is embedded in the elastic material 120. The laminated body of the piezoelectric element 150, the first vibrating member 140, and the second vibrating member 130 is disposed so that the piezoelectric element 150 faces the upper surface side of the support portion 110. That is, the vibrator 100 oscillates sound waves on the upper surface side of the support part 110.

  The bottom surface of the support part 110 is closed. Therefore, a closed space is formed by the second vibrating member 130 and the support part 110. This closed space is connected to the outside through a through hole 112 formed in the bottom surface of the support portion 110.

  Further, terminals 172 and 174 are provided on the bottom surface of the support portion 110. The terminal 172 is connected to the back electrode of the piezoelectric element 150 through a wiring. In the example shown in this drawing, the first vibrating member 140 also serves as the back electrode of the piezoelectric element 150. Further, the terminal 174 is connected to the surface electrode of the piezoelectric element 150 through wiring. Terminals 172 and 174 are connected to the control unit 20.

  A cone 160 is fixed to the upper surface of the piezoelectric element 150 via an adhesive layer 162. The cone 160 is made of metal, for example, and is provided to increase the sound wave output from the vibrator 100.

  FIG. 9 is a diagram illustrating a functional configuration of the control unit 20. The control unit 20 includes a modulation signal generation unit 22, a carrier signal generation unit 24, a plurality of switches 26, and a switching control unit 28.

  The modulation signal generation unit 22 generates a modulation signal based on an audio signal input from the outside. The carrier signal generation unit 24 generates a carrier signal. Note that the modulation signal and the carrier wave are preferably the resonance frequency of the vibrator composed of the piezoelectric element 150, the first vibration member 140, and the second vibration member 130, for example, the fundamental resonance frequency.

  The plurality of switches 26 are connected to different vibrators 100, respectively. When the switch 26 is switched, whether the carrier signal, the modulation signal, or nothing is input to the vibrator 100 is switched. The switching control unit 28 controls the switch 26. The switch 26 may be a mechanical switch or a transistor.

  Also according to this embodiment, the same effect as that of the first embodiment can be obtained. In addition, a piezoelectric element 150 is provided as a vibration source of the vibrator 100. Since the piezoelectric element 150 has a high mechanical quality factor Q, the modulation signal and the carrier wave can be output with high efficiency.

(Third embodiment)
FIG. 10 is a diagram illustrating a configuration of the oscillation device according to the third embodiment. The example shown in this figure is the first or the second, except that the vibrator 100 serving as the modulation signal oscillation element 102 and the vibrator 100 serving as the carrier wave oscillation element 104 are different speaker arrays. The configuration is the same as that of the oscillation device shown in the second embodiment.
According to this embodiment, the same effect as that of the first or second embodiment can be obtained.

  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.

DESCRIPTION OF SYMBOLS 10 Speaker array 20 Control part 30 Audible sound generation | occurrence | production area 22 Modulation signal generation part 24 Carrier signal generation part 26 Switch 28 Switching control part 100 Vibrator 102 Oscillation element for modulation signals 104 Carrier oscillation oscillator 110 Support part 112 Through-hole 120 Elasticity Material 130 Second vibrating member 140 First vibrating member 150 Piezoelectric element 160 Cone 162 Adhesive layer 172 Terminal 174 Terminal

Claims (10)

A plurality of vibrators arranged side by side;
Control means for inputting an oscillation signal to the plurality of vibrators to oscillate;
With
The control means includes
Either a modulation signal for a parametric speaker or a carrier signal having the same frequency as the modulation signal is input as the oscillation signal to the plurality of vibrators.
An oscillation device that switches whether at least one of the modulation signal and the carrier signal is input to the at least one vibrator or not. The oscillation device according to claim 1,
The oscillation device capable of switching whether the control means inputs any of the modulation signal and the carrier signal or does not input any signal to all the vibrators. The oscillation device according to claim 1 or 2,
The oscillator has a piezoelectric element as a vibration source. In the oscillation device according to any one of claims 1 to 3,
The control means controls an audible sound generation area by switching whether the modulation signal or the carrier signal is input to the at least one vibrator or not to input any signal. Oscillator. The oscillation device according to claim 4,
The control device further controls an audible sound generation area by controlling amplitudes of the modulation signal and the carrier signal. The oscillation device according to claim 4 or 5, wherein the control means further controls the position and number of the vibrator that inputs the modulation signal and the position and number of the vibrator that inputs the carrier signal. An oscillating device that controls the audible sound generation area. To a plurality of vibrators arranged side by side, either a modulation signal for a parametric speaker or a carrier signal having the same frequency as the modulation signal is input,
An oscillation method for controlling an audible sound generation area by switching whether at least one of the modulation signal and the carrier signal is input or not to be input to at least one of the vibrators. The oscillation method according to claim 7,
An oscillation method in which the vibrator has a piezoelectric element as a vibration source. The oscillation method according to claim 7 or 8,
The oscillation method in which the control means further controls an audible sound generation area by controlling amplitudes of the modulation signal and the carrier signal. 10. The oscillation method according to claim 7, further comprising controlling the position and number of the vibrator that inputs the modulation signal and the position and number of the vibrator that inputs the carrier signal. An oscillation method that controls the audible sound generation area.

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