JP2013150076A - Electronic apparatus and oscillation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To narrow a demodulation area for demodulation of audible sound in a parametric speaker.SOLUTION: A wall member 200 encloses a first oscillator 101 and a second oscillator 102. A control part 50 inputs a first oscillation signal for oscillating a first sonic wave to the first oscillator 101. The control part 50 inputs a second oscillation signal for oscillating a second sonic wave to the second oscillator 102. The traveling direction or directivity of the second sonic wave is different from that of the first sonic wave. The first sonic wave and the second sonic wave are ultrasonic waves and waves for a parametric speaker, and also at least one of the two sonic waves is at least partially reflected against the wall member 200. The control part 50 controls at least one of the first sonic wave and the second sonic wave to thereby control an overlapping area 20 where the first sonic wave overlaps the second sonic wave.

Description

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

  Parametric speakers are highly oriented because they use ultrasonic waves as modulated waves. For this reason, when a parametric speaker is used as an audio output device of an electronic device, it is difficult for people other than the user of the electronic device to recognize the sound. For example, Patent Document 1 describes that two types of ultrasonic waves having different wavelengths are oscillated, and an audible sound is demodulated in a region where these two types of ultrasonic waves overlap. Patent Document 1 describes that the oscillation directions of two types of ultrasonic waves can be controlled without mechanically moving a speaker serving as an oscillation source.

JP 2002-345077 A

  In a parametric speaker, a technique for further narrowing a demodulation region in which audible sound is demodulated is desired.

  An object of the present invention is to provide an electronic device and an oscillation method that have a parametric speaker and can further narrow a demodulation region in which audible sound is demodulated.

According to the present invention, a first vibrator and a second vibrator;
A wall member provided so as to surround the first vibrator and the second vibrator;
Control means for inputting an oscillation signal to the first vibrator and the second vibrator;
With
The control means inputs a first oscillation signal for causing the first vibrator to oscillate a first sound wave, and the second vibrator has a second traveling direction or directivity different from that of the first sound wave. Input the second oscillation signal to oscillate the sound wave,
The first sound wave and the second sound wave are both ultrasonic waves and waves for a parametric speaker, and at least a part of at least one of them is reflected by the wall member,
The control means provides an electronic device that controls an overlapping region where the first sound wave and the second sound wave overlap by controlling at least one of the first sound wave and the second sound wave.

According to the present invention, the first vibrator and the second vibrator are surrounded by the wall member,
To input a first oscillation signal for oscillating a first sound wave to the first vibrator, and to cause the second vibrator to oscillate a second sound wave having a traveling direction or directivity different from that of the first sound wave. The second oscillation signal of
The first sound wave and the second sound wave are both ultrasonic waves and waves for a parametric speaker, and at least a part of at least one of them is reflected by the wall member,
By controlling at least one of the first sound wave and the second sound wave, an oscillation method for controlling an overlapping region where the first sound wave and the second sound wave overlap is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the demodulation area | region where an audible sound can demodulate in a parametric speaker can be narrowed further.

It is a figure which shows the structure of the electronic device which concerns on 1st Embodiment. It is a figure which shows operation | movement of the electronic device which concerns on 2nd Embodiment. It is a figure which shows the structure of the electronic device which concerns on 3rd Embodiment. 2 is a plan view showing a configuration of an oscillation device 10. FIG. It is AA 'sectional drawing of FIG. It is a figure which shows the modification of the AA 'cross section of FIG. It is a top view which shows the structure of the electronic device which concerns on 4th 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 a configuration of an electronic device according to the first embodiment. The electronic device includes a first vibrator 101, a second vibrator 102, a wall member 200, and a control unit 50. The wall member 200 surrounds the first vibrator 101 and the second vibrator 102. The control unit 50 inputs a first oscillation signal for oscillating the first sound wave to the first vibrator 101. Further, the control unit 50 inputs a second oscillation signal for oscillating the second sound wave to the second vibrator 102. The second sound wave has a different traveling direction or directivity from the first sound wave. The first sound wave and the second sound wave are both ultrasonic waves and are waves for a parametric speaker, and at least a part of at least one of the first sound wave and the second sound wave is reflected by the wall member 200. And the control part 50 controls the overlapping area | region 20 where a 1st sound wave and a 2nd sound wave overlap by controlling at least one of a 1st sound wave and a 2nd sound wave.

  The first oscillation signal and the second oscillation signal are generated, for example, by modulating audible sound. In this case, the audible sound is demodulated from each of the first sound wave and the second sound wave. In the overlapping region 20, the sound pressure of the demodulated audible sound becomes high. For this reason, by appropriately controlling the sound pressure of the first sound wave and the sound pressure of the second sound wave so that an audible sound cannot be heard by a person's ears, The demodulation area to be demodulated can be regarded as the overlapping area 20. In this case, the demodulation area can be further narrowed.

  The first sound wave and the second sound wave may not be modulated signals obtained by modulating audible sound. In this case, a modulated wave obtained by modulating audible sound is output from an oscillation device different from the first vibrator 101 and the second vibrator 102. In this case, the audible sound can be demodulated only in the overlapping region 20. The details of this technique are as described in Patent Document 1, for example.

  In the present embodiment, the second sound wave oscillated by the second vibrator 102 has a lower frequency than the first sound wave oscillated by the first vibrator 101. For this reason, the second sound wave has lower directivity than the first sound wave and is reflected by the wall member 200. For this reason, compared with the case where the wall member 200 is not provided, the overlapping region 20 can be narrowed.

  The first sound wave is preferably the resonance frequency of the first vibrator 101, and the second sound wave is preferably the resonance frequency of the second vibrator 102. In particular, in the present embodiment, the first vibrator 101 and the second vibrator 102 have the same structure, and the fundamental resonance frequencies are equal to each other. The first sound wave has an n-order resonance frequency (for example, n = 1) of the first vibrator 101, and the second sound wave has an m-order (where m <n: for example, m = 2) of the second vibrator 102. Resonance frequency.

  Further, the control unit 50 generates the first oscillation signal and the second oscillation signal as described above. When these are parametric speaker modulation waves, the modulation scheme used here is, for example, AM (Amplitude Modulation) modulation, DSB (Double Side Band) modulation, SSB (Single Side Band) modulation, or FM (Frequency Modulation) modulation. It is.

  As described above, according to the present embodiment, the first sound wave and the second sound wave are both ultrasonic waves and waves for a parametric speaker, and at least a part of at least one of them is reflected by the wall member 200. And the control part 50 controls the overlapping area | region 20 where a 1st sound wave and a 2nd sound wave overlap by controlling at least one of a 1st sound wave and a 2nd sound wave. Therefore, the demodulation area can be narrowed by making the demodulation area of the parametric speaker coincide with the overlapping area 20.

(Second Embodiment)
FIG. 2 is a diagram for explaining the operation of the electronic device according to the second embodiment. The electronic device according to the present embodiment has the same configuration as the electronic device according to the first embodiment except for the following points.

  First, the first sound wave and the second sound wave have different traveling directions. The control unit 50 controls the traveling direction of the first sound wave and the traveling direction of the second sound wave, for example, by using the technique described in Patent Document 1. The first sound wave and the second sound wave are reflected by different portions of the wall member 200.

  Also according to this embodiment, the same effect as that of the first embodiment can be obtained. In the present embodiment, the first sound wave and the second sound wave may have the same frequency or different frequencies.

(Third embodiment)
FIG. 3 is a diagram illustrating a configuration of an electronic device according to the third embodiment. The present embodiment has the same configuration as the electronic device according to the first embodiment or the second embodiment except for the following points.

  First, a bottom plate 210 is formed at the lower end of the wall member 200. On the bottom plate 210, the oscillation device 10 is provided. The oscillation device 10 includes a first vibrator 101 and a second vibrator 102.

  FIG. 4 is a plan view showing the configuration of the oscillation device 10. The oscillation device 10 has a structure in which a plurality of transducers 100 are arranged in an array. Specifically, the oscillation device 10 has a frame member 130. The frame member 130 has a plurality of arrays of openings. A vibrator 100 is provided in each opening. The vibrator 100 functions as the first vibrator 101 or the second vibrator 102. Whether the vibrator 100 functions as the first vibrator 101 or the second vibrator 102 depends on whether the control unit 50 (shown in FIG. 3) inputs the first oscillation signal or the second oscillation signal. It is determined by.

  FIG. 5 is a cross-sectional view taken along the line AA ′ of FIG. The vibrator 100 includes a piezoelectric element 110 and a vibration member 120. The piezoelectric element 110 is made of piezoelectric ceramics such as lead zirconate titanate (PZT). However, the piezoelectric element 110 may be formed of a polymer material exhibiting piezoelectric characteristics, such as polyvinylidene fluoride. In any case, the planar shape of the piezoelectric element 110 is smaller than the planar shape of the vibration member 120. The vibration member 120 has a sheet shape and is formed of a metal such as aluminum alloy, phosphor bronze, titanium, titanium alloy, or stainless steel. The edge of the vibration member 120 is held by the frame member 130.

  As shown in FIG. 6, the second vibration member 140 may be located under the vibration member 120. The planar shape of the second vibration member 140 is larger than that of the vibration member 120. The frame member 130 holds the edge of the second vibrating member 140. The second vibration member 140 is formed of a material having lower rigidity than the vibration member 120. For this reason, the rigidity of the second vibrating member 140 is higher than that of the vibrating member 120. The second vibrating member 140 is made of a resin material such as urethane, PET (Polyethylene terephthalate), or polyethylene. The vibration member 120 may be made of a resin material having higher rigidity than the second vibration member 140, such as an epoxy resin, acrylic, polyimide, or the like, in addition to a metal such as aluminum alloy, phosphor bronze, titanium, titanium alloy, or stainless steel. Alternatively, polycarbonate may be used.

  As described above, also according to this embodiment, the same effect as that of the first embodiment can be obtained. In addition, it is possible to electrically change which of the vibrators 100 arranged in an array is used as the first vibrator 101 and the second vibrator 102. Therefore, the positions of the first vibrator 101 and the second vibrator can be changed to be most suitable for the position of the desired overlapping region 20.

(Fourth embodiment)
FIG. 7 is a plan view showing a configuration of an electronic apparatus 300 according to the fourth embodiment. The electronic device 300 according to the present embodiment is a portable electronic device, such as a portable communication terminal, a portable personal computer, a portable game device, a portable audio playback device, or a portable video playback device. However, the electronic device 300 may be other devices. The electronic device 300 includes a display 302 and the oscillation device 10. The oscillation device 10 is used as a speaker.

  The configuration of the oscillation device 10 is as shown in the second embodiment. The wall member 200 may be a side surface of a sound hole provided in the housing of the electronic device 300.

  The electronic device 300 has an imaging unit 304. The imaging unit 304 images the face of the user of the electronic device 300. The control unit 50 determines the position of the user's ear by processing the user's face image captured by the imaging unit 304. Then, the control unit 50 controls the first oscillation signal input to the first vibrator 101 and the second oscillation signal input to the second vibrator 102 in accordance with the determined ear position.

  According to this embodiment, the same effect as that of the 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.

10 Oscillator 20 Overlapping Area 50 Control Unit 100 Vibrator 101 First Vibrator 102 Second Vibrator 110 Piezoelectric Element 120 Vibrating Member 130 Frame 140 Second Vibrating Member 200 Wall Member 210 Bottom Plate 300 Electronic Device 302 Display 304 Imaging Unit

Claims (10)

A first vibrator and a second vibrator;
A wall member provided so as to surround the first vibrator and the second vibrator;
Control means for inputting an oscillation signal to the first vibrator and the second vibrator;
With
The control means inputs a first oscillation signal for causing the first vibrator to oscillate a first sound wave, and the second vibrator has a second traveling direction or directivity different from that of the first sound wave. Input the second oscillation signal to oscillate the sound wave,
The first sound wave and the second sound wave are both ultrasonic waves and waves for a parametric speaker, and at least a part of at least one of them is reflected by the wall member,
The control device is an electronic device that controls an overlapping region where the first sound wave and the second sound wave overlap by controlling at least one of the first sound wave and the second sound wave. The electronic device according to claim 1,
The electronic device in which the second sound wave has a frequency smaller than that of the first sound wave and at least a part of the second sound wave is reflected by the wall member. The electronic device according to claim 2.
The first vibrator and the second vibrator have the same structure,
The first sound wave is an n-th resonance frequency of the first vibrator;
The electronic device, wherein the second sound wave has an m-th order (where m <n) resonance frequency of the second vibrator. The electronic device according to claim 1,
The electronic device in which the first sound wave and the second sound wave have different traveling directions and are reflected by different portions of the wall member. The electronic device according to any one of claims 1 to 4,
An electronic device that demodulates audible sound from each of the first sound wave and the second sound wave. The first vibrator and the second vibrator are surrounded by a wall member,
To input a first oscillation signal for oscillating a first sound wave to the first vibrator, and to cause the second vibrator to oscillate a second sound wave having a traveling direction or directivity different from that of the first sound wave. The second oscillation signal of
The first sound wave and the second sound wave are both ultrasonic waves and waves for a parametric speaker, and at least a part of at least one of them is reflected by the wall member,
An oscillation method for controlling an overlapping region in which the first sound wave and the second sound wave overlap by controlling at least one of the first sound wave and the second sound wave. The oscillation method according to claim 6, wherein
The oscillation method in which the second sound wave has a frequency smaller than that of the first sound wave and at least a part of the second sound wave is reflected by the wall member. The oscillation method according to claim 7,
The first vibrator and the second vibrator have the same structure,
The first sound wave is an n-th resonance frequency of the first vibrator;
The oscillation method in which the second sound wave has an m-th (where m <n) resonance frequency of the second vibrator. The oscillation method according to claim 6, wherein
The oscillation method in which the first sound wave and the second sound wave have different traveling directions and are reflected by different portions of the wall member. In the oscillation method as described in any one of Claims 6-9,
An oscillation method in which audible sound is demodulated from each of the first sound wave and the second sound wave.

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