JP2012029086A - Electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve downsizing of an electronic apparatus.SOLUTION: The electronic apparatus 100 includes an oscillation device 10, a housing 20 that has the oscillation device 10 inside it and a hole 50 formed on its surface, and a plurality of components 22 disposed inside the housing 20, the oscillation device 10 emitting an ultrasound wave 40 from a first vibration surface and no components 22 being located on a linear line 30 connecting at least part of the hole 50 and the first vibration surface possessed by the oscillation device 10. Therefore the ultrasound wave 40 passes through a space between the components 22 and is radiated to the outside of the housing 20.

Description

  The present invention relates to an electronic device using ultrasonic waves.

  There is a piezoelectric electroacoustic transducer as an electroacoustic transducer such as a portable device. Piezoelectric electroacoustic transducers generate vibration amplitude by utilizing the expansion and contraction generated by applying an electric field to a piezoelectric vibrator. Piezoelectric electroacoustic transducers do not require a large number of members in order to generate vibration amplitude, and are advantageous for thinning.

  As a technique related to a speaker mounted on a portable device or the like, one described in Patent Document 1 can be cited. The technique described in Patent Document 1 is to achieve excellent driving characteristics and acoustic characteristics even with a small size regarding an electrodynamic electroacoustic transducer using a voice coil or the like.

  A piezoelectric electroacoustic transducer may be used as a parametric speaker using ultrasonic waves. A parametric speaker demodulates audible sound from modulated ultrasonic waves using the phenomenon of air density. Since ultrasonic waves are used, high directivity can be realized as compared with a normal speaker.

JP 2003-111194 A

  There is a need for a technology that can further reduce the size of electronic devices having speakers.

  An object of the present invention is to reduce the size of an electronic device.

According to the present invention, an oscillation device;
A housing having the oscillation device inside and having a first hole on the surface;
A plurality of components provided inside the housing;
With
The oscillation device emits ultrasonic waves from the first vibration surface,
An electronic device in which any of the components is not located on a first straight line connecting at least a part of the first hole and at least a part of the first vibration surface is provided.

  According to the present invention, it is possible to reduce the size of an electronic device.

It is sectional drawing which shows the electronic device which concerns on 1st Embodiment. It is sectional drawing which shows the oscillation apparatus shown in FIG. It is sectional drawing which shows the piezoelectric vibrator shown in FIG. It is sectional drawing which shows the modification of the electronic device shown in FIG. It is sectional drawing which shows the electronic device which concerns on 2nd 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.

  FIG. 1 is a cross-sectional view showing an electronic device 100 according to the first embodiment. The electronic device 100 includes an oscillation device 10, a housing 20, and a plurality of component parts 22. The electronic device 100 is, for example, a mobile communication terminal, a laptop computer, or a small game device.

  The housing 20 has the oscillation device 10 inside. A hole 50 is provided on the surface of the housing 20. The plurality of component parts 22 are provided inside the housing 20. The oscillation device 10 emits an ultrasonic wave 40 from the first vibration surface. None of the component parts 22 is positioned on the straight line 30 connecting at least a part of the hole 50 and at least a part of the first vibration surface. Hereinafter, the configuration of the electronic device 100 will be described in detail with reference to FIGS.

  As shown in FIG. 1, a hole 55 is provided on the surface of the housing 20. The oscillation device 10 emits an ultrasonic wave 45 from a second vibration surface constituted by a surface opposite to the first vibration surface. None of the component parts 22 is positioned on the straight line 35 connecting at least a part of the hole 55 and at least a part of the second vibration surface.

The first vibration surface and the second vibration surface are provided to face the side surface of the housing 20. The holes 50 and 55 are provided on the side surface of the housing 20. When the electronic device 100 is a mobile communication terminal, the holes 50 and 55 are configured by a gap between, for example, a button or an imaging device and the housing 20. The straight line 30 is perpendicular to the first vibration surface. The straight line 35 is perpendicular to the second vibration surface. Of the places where the holes 50 and 55 and the oscillation device 10 overlap, the area where the component 22 is not located may be, for example, 0.1 mm ² or more.

  As illustrated in FIG. 2, the oscillation device 10 includes a piezoelectric vibrator 60, a vibration member 80, and a support member 70. The vibration member 80 restrains the piezoelectric vibrator 60. The support member 70 supports the vibration member 80. The oscillation device 10 further includes a control unit 90 and a signal generation unit 92. The signal generation unit 92 is connected to the piezoelectric vibrator 60 and generates an electric signal input to the piezoelectric vibrator 60. The control unit 90 is connected to the signal generation unit 92 and controls signal generation by the signal generation unit 92 based on information input from the outside. Since the oscillation device 10 is used as a speaker, information input to the control unit 90 is an audio signal.

  In the present embodiment, the oscillation device 10 is used as a parametric speaker. Therefore, the control unit 90 inputs a modulation signal as a parametric speaker via the signal generation unit 92. When used as a parametric speaker, the piezoelectric vibrator 60 uses a sound wave of 20 kHz or more, for example, 100 kHz, as a signal transport wave. In the oscillation device 10, for example, a plurality of piezoelectric vibrators 60 and vibration members 80 are provided in an array. Thereby, the directivity of the ultrasonic waves 40 and 45 emitted from the oscillation device 10 can be improved. Further, the piezoelectric vibrator 60 and the vibration member 80 may be single.

FIG. 3 is a cross-sectional view showing the piezoelectric vibrator 60 shown in FIG. As shown in FIG. 3, the piezoelectric vibrator 60 includes a piezoelectric body 62, an upper electrode 64, and a lower electrode 66. The piezoelectric vibrator 60 has, for example, a circle, an ellipse, or a rectangle. The piezoelectric body 62 is sandwiched between the upper electrode 64 and the lower electrode 66. The piezoelectric body 62 is made of a material having a piezoelectric effect, and is made of, for example, lead zirconate titanate (PZT), barium titanate (BaTiO ₃ ), or the like. The thickness of the piezoelectric body 62 is preferably 10 um to 1 mm. When the thickness is less than 10 μm, the piezoelectric body 62 is made of a brittle material, and thus is easily damaged. On the other hand, when the thickness exceeds 1 mm, the electric field strength of the piezoelectric body 62 is reduced. Therefore, the energy conversion efficiency is reduced.

  The upper electrode 64 and the lower electrode 66 are made of, for example, silver or a silver / palladium alloy. The thickness of the upper electrode 64 and the lower electrode 66 is preferably 1 to 50 um. When the thickness is less than 1 μm, it becomes difficult to form the film uniformly. On the other hand, when it exceeds 50 um, the upper electrode 64 or the lower electrode 66 becomes a constraining surface with respect to the piezoelectric body 62 and causes a decrease in energy conversion efficiency.

  The vibration member 80 is made of a material having a high elastic modulus with respect to the ceramic material, and is made of, for example, phosphor bronze or stainless steel. The thickness of the vibration member 80 is preferably 5 to 500 μm. The longitudinal elastic modulus of the vibration member 80 is preferably 1 to 500 GPa. When the longitudinal elastic modulus of the vibration member 80 is excessively low or high, the characteristics and reliability as a mechanical vibrator may be impaired.

  The electronic device 100 further includes a mounting substrate 24. The mounting substrate 24 is disposed in parallel with the upper surface and the bottom surface of the housing 20. The mounting board 24 is, for example, a printed wiring board. The component 22 is mounted on the mounting board 24. Further, the heights of the component parts 22 on the mounting substrate 24 are different from each other. The component 22 includes an electronic component such as a discrete component or a semiconductor package. The oscillation device 10 is provided in a direction crossing the mounting substrate 24. Further, the straight lines 30 and 35 do not intersect with the mounting substrate 24.

  FIG. 4 is a cross-sectional view showing a modification of electronic device 100 shown in FIG. As shown in FIG. 4, the electronic device 100 may include a flexible substrate 25. In this case, the flexible substrate 25 is mounted on the mounting substrate 24. The oscillation device 10 is fixed by the flexible substrate 25. And the through-hole is provided in the part which cross | intersects the straight lines 30 and 35 among the flexible substrates 25. FIG. 4 indicates the shape of the flexible substrate 25 around the through hole.

  Further, when the electronic device 100 is a mobile communication terminal, a part of the component parts 22 configures an imaging device, for example. At this time, the oscillation device 10 is disposed, for example, at a position close to the imaging device. In many cases, components constituting the imaging apparatus are larger than other components. Therefore, in this case, it becomes easy to incorporate the oscillation device 10 into the electronic device 100.

  Next, the effect of this embodiment will be described. In the electronic apparatus 100 according to the present embodiment, the component 22 is not located on a straight line connecting the first vibration surface that emits the ultrasonic wave 40 and the hole 50. Moreover, the ultrasonic wave 40 is superior in straightness as compared with the audible sound wave. For this reason, the ultrasonic wave 40 is radiated from the hole 50 to the outside of the housing 20 through the gap between the component parts 22. Therefore, sound reproduction can be performed without providing a waveguide, and the electronic device can be downsized.

  Further, a hole 50 and a hole 55 are provided on the surface of the housing 20. Therefore, the ultrasonic waves 40 and 45 emitted from both the first vibration surface and the second vibration surface can be used, and sound reproduction can be performed with high efficiency. Furthermore, the ultrasonic waves 40 and 45 emitted from the oscillation device 10 have many components perpendicular to the first vibration surface and the second vibration surface. Therefore, when the straight line 30 is perpendicular to the first vibration surface and the straight line 35 is perpendicular to the second vibration surface, sound reproduction can be performed with higher efficiency.

  FIG. 5 is a cross-sectional view illustrating the electronic device 102 according to the second embodiment, and corresponds to FIG. 1 according to the first embodiment. The electronic device 102 according to the present embodiment is the same as the electronic device 100 according to the first embodiment except for the direction in which the oscillation device 10 is provided. 5 indicates the shape of the mounting substrate 24 around the through hole.

  As shown in FIG. 5, the oscillation device 10 is provided in a direction that does not cross the mounting substrate 24. A through hole is provided in a portion of the mounting substrate 24 that intersects with the straight lines 30 and 35. The holes 50 and 55 are provided on the upper surface and the bottom surface of the housing 20. When the electronic device 102 is a mobile communication terminal, the first vibration surface and the second vibration surface are provided so as to face, for example, the upper surface or the bottom surface of the housing 20.

  Also in this embodiment, the same effect as that of the first embodiment can be obtained. Further, in the electronic device 102 according to the present embodiment, the oscillation device 10 is provided in a direction that does not cross the mounting substrate 24. In many cases, the oscillation device 10 has a width in the vibration film forming direction larger than a width in the vibration direction of the vibration film. Therefore, the electronic device can be made thinner than in the first embodiment.

  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 Oscillator 20 Housing | casing 22 Component 24 Mounting board 25 Flexible board 30 Straight line 35 Straight line 40 Ultrasonic 45 Ultrasonic 50 Hole 55 Hole 60 Piezoelectric vibrator 62 Piezoelectric body 64 Upper electrode 66 Lower electrode 70 Support member 80 Vibration member 90 Control Unit 92 signal generation unit 100 electronic device 102 electronic device

Claims (9)

An oscillation device;
A housing having the oscillation device inside and having a first hole on the surface;
A plurality of components provided inside the housing;
With
The oscillation device emits ultrasonic waves from the first vibration surface,
An electronic device in which any of the components is not located on a first straight line connecting at least a part of the first hole and at least a part of the first vibration surface. The electronic device according to claim 1,
A signal generator connected to the oscillation device;
A control unit that is connected to the signal generation unit and controls the signal generation unit to generate a signal that oscillates an ultrasonic wave obtained by modulating audio data of an audible sound;
An electronic device further comprising: The electronic device according to claim 1 or 2,
The electronic device in which the first straight line is perpendicular to the first vibration surface. The electronic device according to any one of claims 1 to 3,
A mounting substrate,
The component is mounted on the mounting board,
The oscillation device is provided in a direction intersecting with the mounting substrate,
The first straight line is an electronic device that does not intersect the mounting substrate. The electronic device according to any one of claims 1 to 3,
A mounting substrate,
The component is mounted on the mounting board,
The oscillation device is provided in a direction not intersecting with the mounting substrate,
An electronic device in which a through hole is provided in a portion of the mounting substrate that intersects the first straight line. The electronic device according to any one of claims 1 to 5,
The surface of the housing is provided with a second hole,
The oscillation device emits ultrasonic waves from a second vibration surface constituted by a surface opposite to the first vibration surface;
An electronic apparatus in which any of the components is not located on a second straight line connecting at least a part of the second hole and at least a part of the second vibration surface. The electronic device according to any one of claims 1 to 6,
A flexible substrate,
The oscillation device is fixed by the flexible substrate,
An electronic device in which a through hole is provided in a portion of the flexible substrate that intersects the first straight line. The electronic device according to claim 1,
The electronic device is an electronic device that is a mobile communication terminal. The electronic device according to claim 8,
Some of the components constitute an imaging device,
The oscillation device is an electronic device disposed at a position close to the imaging device.

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