JP2012217031A - Oscillation device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To downsize an electronic apparatus.SOLUTION: An oscillation device 100 includes: a piezoelectric vibrator 10; and a plurality of support pillars 30 that are provided on a surface of the piezoelectric vibrator 10 and support the piezoelectric vibrator 10. The support pillars 30 are arranged in a first direction and in a second direction perpendicular to the first direction so as to be separated from one another. Thus, a plurality of sound waves are allowed to be output from the single piezoelectric vibrator 10, without the need for arranging a plurality of oscillation devices. Therefore, an electronic apparatus is allowed to be downsized.

Description

  The present invention relates to an oscillation device having a piezoelectric vibrator and an electronic apparatus.

As an electroacoustic transducer mounted on an electronic device, there is a piezoelectric electroacoustic transducer. 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 regarding a piezoelectric electroacoustic transducer, for example, there are those described in Patent Documents 1 to 5.

  The techniques described in Patent Documents 1 to 3 relate to a parametric speaker using a piezoelectric film as an emitter. The technique described in Patent Document 4 includes a piezoelectric film diaphragm having a flexibility and a speaker unit, and vibrates them simultaneously. Patent Document 5 discloses a technique of using a piezoelectric film for a sound reproduction screen.

Special Table 2002-526004 Special table 2007-503742 gazette Special table 2003-520002 gazette JP 2010-62819 A JP 2006-180504 A

  An electronic device equipped with an oscillation device is required to be downsized.

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

According to the present invention, a piezoelectric vibrator;
A plurality of pillars provided on one surface of the piezoelectric vibrator and supporting the piezoelectric vibrator;
With
An oscillation device is provided in which the plurality of support columns are arranged so as to be separated from each other in a first direction and a second direction perpendicular to the first direction.

  According to the present invention, an electronic apparatus equipped with the above-described oscillation device is provided.

  According to the present invention, the size of the oscillation device can be reduced.

1 is a plan view showing an oscillation device according to a first embodiment. It is sectional drawing which shows the oscillation apparatus shown in FIG. It is a perspective view for demonstrating the structure of the oscillation apparatus shown in FIG. It is sectional drawing which shows the piezoelectric vibrator shown in FIG. It is a top view which shows the oscillation apparatus 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 plan view showing an oscillation device 100 according to the first embodiment. The oscillation device 100 according to the present embodiment includes the piezoelectric vibrator 10 and a plurality of support columns 30. The oscillation device 100 is mounted on an electronic device such as a mobile phone.

  The plurality of support columns 30 are provided on one surface of the piezoelectric vibrator 10 and support the piezoelectric vibrator 10. The plurality of support columns 30 are arranged so as to be separated from each other in the first direction and the second direction perpendicular to the first direction. Hereinafter, the configuration of the oscillation device 100 will be described in detail.

  As shown in FIG. 1, the plurality of support columns 30 are arranged in an array on one surface of the piezoelectric vibrator 10, for example. In this case, the plurality of support columns 30 are arranged at equal intervals in the first direction and the second direction. The column 30 has a width in a plane direction parallel to one surface of the piezoelectric vibrator 10 of, for example, 0.05 mm or more and 5 mm or less.

  FIG. 2 is a cross-sectional view showing the oscillation device 100 shown in FIG. An arrow in FIG. 2 indicates a sound wave output from the oscillation device 100. The piezoelectric vibrator 10 is restrained by a plurality of support columns 30 provided on one surface. For this reason, as shown in FIGS. 1 and 2, a sound wave is output from each radiation surface 20 with the region surrounded by the column 30 as the radiation surface 20.

  FIG. 3 is a perspective view for explaining the configuration of the oscillation device 100 shown in FIG. The oscillation device 100 is provided by joining the piezoelectric vibrator 10 and the plurality of support columns 30 illustrated in FIG. 3. As shown in FIG. 3, the shape of the support column 30 is, for example, a columnar shape, but is not limited thereto.

  FIG. 4 is a cross-sectional view showing the piezoelectric vibrator 10 shown in FIG. As shown in FIG. 4, the piezoelectric vibrator 10 includes a piezoelectric body 70, an upper electrode 72, and a lower electrode 74. The piezoelectric body 70 is sandwiched between the upper electrode 72 and the lower electrode 74. The piezoelectric body 70 is polarized in the thickness direction (vertical direction in FIG. 4). The planar shape of the piezoelectric vibrator 10 is, for example, a quadrangle, a circle, or an ellipse.

The piezoelectric body 70 is made of a material having a piezoelectric effect, for example, lead zirconate titanate (PZT) or barium titanate (BaTiO ₃ ) as a material having high electromechanical conversion efficiency. The thickness of the piezoelectric body 70 is preferably 10 μm to 1 mm. When the thickness is less than 10 μm, the piezoelectric body 70 is made of a brittle material, and thus is easily damaged during handling. On the other hand, when the thickness exceeds 1 mm, the electric field strength of the piezoelectric body 70 is reduced. For this reason, the energy conversion efficiency is reduced.

  The upper electrode 72 and the lower electrode 74 are made of a material having electrical conductivity, for example, silver or a silver / palladium alloy. Silver is a low-resistance general-purpose material and is advantageous from the viewpoint of manufacturing cost and manufacturing process. Further, the silver / palladium alloy is a low resistance material excellent in oxidation resistance and excellent in reliability. The thickness of the upper electrode 72 and the lower electrode 74 is preferably 1 to 50 μm. When the thickness is less than 1 μm, it becomes difficult to form the film uniformly. On the other hand, when the thickness exceeds 50 μm, the upper electrode 72 or the lower electrode 74 serves as a restraint surface with respect to the piezoelectric body 70 and causes a decrease in energy conversion efficiency.

  The oscillation device 100 includes a control unit 90 and a signal generation unit 92. The signal generator 92 is connected to the piezoelectric vibrator 10 and generates an electric signal input to the piezoelectric vibrator 10. The control unit 90 is connected to the signal generation unit 92 and controls signal generation by the signal generation unit 92. The control unit 90 controls the generation of the signal of the signal generation unit 92 based on information input from the outside, whereby the output of the oscillation device 100 can be controlled.

  In the present embodiment, the oscillation device 100 is used as a parametric speaker. When the oscillation device 100 is used as a parametric speaker, the control unit 90 inputs a modulation signal as a parametric speaker via the signal generation unit 92. In this case, the piezoelectric vibrator 10 uses a sound wave of 20 kHz or more, for example, 100 kHz, as a signal transport wave.

Note that the oscillation device 100 can also be used as a normal speaker. When the oscillation device 100 is used as a normal speaker, the control unit 90 inputs an audio signal as it is to the piezoelectric vibrator 10 via the signal generation unit 92.
Furthermore, the oscillation device 100 can also be used as an ultrasonic sensor. When the oscillation device 100 is used as an ultrasonic sensor, a signal input to the control unit 90 is a command signal for oscillating a sound wave. When the oscillation device 100 is used as a sound wave sensor, the signal generation unit 92 causes the piezoelectric vibrator 10 to generate a sound wave having a resonance frequency of the piezoelectric vibrator 10.

In FIG. 1, “x” indicates the distance between the center point between adjacent struts 30 and the center point adjacent thereto. When the wavelength of the sound wave output from the piezoelectric vibrator 10 is λ, x is preferably 1 / 2λ or less, for example, in the first direction and the second direction. In this case, the distance between the centers of the radiation surfaces 20 adjacent to each other in the first direction and the second direction is 1 / 2λ or less.
In the present embodiment, when the distance between the centers of the radiation surfaces 20 adjacent to each other in the first direction and the second direction is 1 / 2λ or less, sound waves output from the radiation surfaces 20 adjacent to each other interfere with each other. This can be suppressed. Thereby, it is possible to realize a highly efficient sound wave output.

  Next, the effect of this embodiment will be described. The piezoelectric electroacoustic transducer is configured by, for example, arranging a plurality of oscillating devices having piezoelectric vibrators in an array to realize high directivity. However, when a plurality of oscillation devices are arranged, it is difficult to reduce the size of the electronic device.

In the present embodiment, the plurality of support columns 30 are arranged so as to be separated from each other in the first direction and the second direction. For this reason, a plurality of radiation surfaces 20 surrounded by the support columns 30 are provided. Accordingly, the piezoelectric vibrator 10 can output sound waves from each of the plurality of radiation surfaces 20.
Thus, according to this embodiment, a plurality of sound waves can be output from one piezoelectric vibrator 10 without arranging a plurality of oscillation devices. Therefore, it is possible to reduce the size of the electronic device.

  Further, the oscillation device 100 according to the present embodiment is formed by constraining one piezoelectric vibrator 10 by a plurality of support columns 30. Thus, according to the present embodiment, it is possible to form the oscillation device 100 without requiring a plurality of members. Therefore, it is possible to manufacture an electronic device at a low cost.

  FIG. 5 is a plan view showing the oscillation device 102 according to the second embodiment, and corresponds to FIG. 1 in the first embodiment. The oscillation device 102 according to the present embodiment has the same configuration as that of the oscillation device 100 according to the first embodiment except for the configuration of the support column 30.

  The plurality of support columns 30 are arranged so that the interval between the set of support columns 30 and the interval between the other set of support columns 30 are different in at least one direction of the first direction and the second direction. In the present embodiment, as shown in FIG. 5, in the first direction and the second direction, the interval between the set of struts 30 and the other set of intervals are different.

  The plurality of support columns 30 are arranged such that the interval between the set of support columns 30 and the interval between the other set of support columns 30 are different in at least one direction of the first direction and the second direction. The area of the radiation surface 20 that the 102 has is different. For example, as illustrated in FIG. 5, the oscillation device 102 includes a radiation surface 22, a radiation surface 24, and a radiation surface 26 having different areas in the same plane as the one surface of the piezoelectric vibrator 10.

Also in this embodiment, the same effect as that of the first embodiment can be obtained.
Further, according to the present embodiment, it is possible to realize the oscillation device 100 having a plurality of radiation surfaces 20 having different areas. The basic resonance frequency of the piezoelectric vibrator depends on the length of the contour shape of the vibration surface. For this reason, when having a plurality of radiation surfaces 20 having different areas, the oscillation device 100 has a plurality of resonance frequencies. Therefore, an output with a high sound pressure level can be realized in a wide frequency band.

  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 Piezoelectric vibrator 20 Radiation surface 22 Radiation surface 24 Radiation surface 26 Radiation surface 30 Support | pillar 70 Piezoelectric body 72 Upper electrode 74 Lower electrode 100 Oscillator 102 Oscillator

Claims (7)

A piezoelectric vibrator;
A plurality of pillars provided on one surface of the piezoelectric vibrator and supporting the piezoelectric vibrator;
With
The oscillation device in which the plurality of support columns are arranged to be separated from each other in a first direction and a second direction perpendicular to the first direction. The oscillation device according to claim 1,
When the wavelength of the sound wave output from the piezoelectric vibrator is λ, in the first direction and the second direction, the distance between the center point between the adjacent struts and the center point adjacent thereto is An oscillation device that is 1 / 2λ or less. The oscillation device according to claim 1 or 2,
The oscillating device in which the support column has a width in a plane direction parallel to the one surface of the piezoelectric vibrator of 0.05 mm or more and 5 mm or less. The oscillation device according to any one of claims 1 to 3,
The oscillation device in which the plurality of support columns are arranged at equal intervals in the first direction and the second direction. The oscillation device according to any one of claims 1 to 3,
The oscillating device in which the plurality of support columns are arranged so that a distance between one set of support columns and a distance between another set of support columns are different in at least one direction of the first direction and the second direction. The oscillation device according to any one of claims 1 to 5,
A signal generator connected to the piezoelectric vibrator;
A control unit that controls output of the piezoelectric vibrator by controlling generation of a signal by the signal generation unit;
An oscillation device comprising:   An electronic apparatus equipped with the oscillation device according to claim 1.

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