JP2012142651A - Oscillation device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve waterproof performance in an electronic apparatus having sound holes.SOLUTION: An oscillation device 100 includes a vibration member 114, a piezoelectric element 111, a waterproof member 121, and a support member 130. The vibration member 114 is a sheet-shaped member. The piezoelectric element 111 is attached to one surface of the vibration member 114. The waterproof member 121 has a sheet shape and is attached to the other surface of the vibration member 114. The waterproof member 121 has a planar shape larger than that of the vibration member 114 and is constituted by a material with waterproof property. The support member 130 is joined with the outer periphery of the waterproof member 121. The support member 130 is joined with the inner surface of a housing 510 so as to surround sound holes 511 in a direction to allow the waterproof member 121 to face the sound holes 511.

Description

  The present invention relates to an oscillation device and an electronic apparatus.

  In recent years, the demand for mobile terminals such as mobile phones and laptop computers has been increasing. In particular, the development of thin mobile terminals with commercial functions such as videophones, video playback, and hands-free phone functions is underway. In these developments, there is an increasing demand for electroacoustic transducers that are small in size and large in output. Conventionally, an electrodynamic electroacoustic transducer is used as an electroacoustic transducer in an electronic device such as a mobile phone. This electrodynamic electroacoustic transducer is composed of a permanent magnet, a voice coil, and a diaphragm. However, the electrodynamic electroacoustic transducer is limited in thickness because of its operation principle and structure. Therefore, for example, as described in Patent Documents 1 to 3, it is expected to use a piezoelectric vibrator as a speaker.

JP 58-028500 Japanese Patent Laid-Open No. 04-170897 Japanese Patent Laid-Open No. 04-368099

  In recent years, waterproofing is required for electronic devices. On the other hand, an electronic device having an audio output function needs to be provided with a sound hole. For this reason, there is a possibility that the waterproof performance of the electronic device is lowered by the sound holes.

  An object of the present invention is to improve waterproof performance in an electronic device having a sound hole.

According to the present invention, a vibrating member;
A piezoelectric element attached to one surface of the vibration member;
A sheet-like waterproof member that is attached to the other surface of the vibration member, has a planar shape that is the same as or more than the vibration member, and is made of a waterproof material;
A support member joined to the outer periphery of the waterproof member;
An oscillation device is provided.

According to the present invention, a housing;
A sound hole provided in the housing;
An oscillation device provided in a position facing the sound hole in the housing;
With
The oscillator is
A vibrating member;
A piezoelectric element attached to one surface of the vibration member;
A sheet-like waterproof member that is attached to the other surface of the vibration member, has a planar shape larger than the vibration member, and is made of a waterproof material;
A support member joined to the outer periphery of the waterproof member;
Have
In the electronic device, the support member is bonded to the inner surface of the casing so as to surround the sound hole in a direction in which the waterproof member faces the sound hole.

  ADVANTAGE OF THE INVENTION According to this invention, waterproof performance can be improved in the electronic device which has a sound hole.

It is sectional drawing which shows the structure of the principal part of the electronic device which concerns on 1st Embodiment. It is a top view of an oscillation apparatus. It is sectional drawing which shows the structure of the electronic device which concerns on 2nd Embodiment. It is a top view 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 cross-sectional view illustrating a configuration of a main part of an electronic device 500 according to the first embodiment. The electronic device 500 includes a housing 510 and the oscillation device 100. The housing 510 has a sound hole 511. The oscillation device 100 is disposed inside the housing 510 at a position facing the sound hole 511 and oscillates sound waves.

  The oscillation device 100 includes a vibration member 114, a piezoelectric element 111, a waterproof member 121, and a support member 130. The vibration member 114 is a sheet-like member. The piezoelectric element 111 is attached to one surface of the vibration member 114. The waterproof member 121 has a sheet shape and is attached to the other surface of the vibration member 114. The waterproof member 121 has a planar shape larger than that of the vibration member 114 and is made of a waterproof material. The support member 130 is joined to the outer periphery of the waterproof member 121. The support member 130 is joined to the inner surface of the housing 510 so as to surround the sound hole 511 so that the waterproof member 121 faces the sound hole 511. Details will be described below.

The material constituting the piezoelectric element 111 may be either an inorganic material or an organic material as long as it has a piezoelectric effect. However, a material having high electromechanical conversion efficiency such as zirconate titanate (PZT) or barium titanate (BaTiO ₃ ) is preferable. The thickness h ₁ of the piezoelectric element 111 is, for example, not less than 10 μm and not more than 1 mm. When the thickness h ₁ is less than 10 μm, there is a possibility that the oscillation device 100 is damaged when the oscillation device is manufactured. Further if the thickness h ₁ of 1mm greater than the electro-mechanical conversion efficiency is too low, not obtained vibration large enough. The reason is that as the thickness of the oscillation device 100 increases, the electric field strength in the piezoelectric vibrator decreases in inverse proportion.

Electrodes 112 are respectively formed on both surfaces of the piezoelectric element 111. Although the material which comprises the electrode 112 is not specifically limited, For example, silver and silver / palladium can be used. Since silver is used as a general-purpose electrode material with low resistance, it has advantages in manufacturing process and cost. Since silver / palladium is a low-resistance material having excellent oxidation resistance, there is an advantage from the viewpoint of reliability. The thickness h ₂ of the electrode 112 is not particularly limited, but the thickness h ₂ is preferably 1 μm or more and 50 μm or less. The thickness h ₂ is less than 1 [mu] m, it becomes difficult to mold the electrode 112 uniformly, as a result, the electromechanical conversion efficiency may be lowered. Further, when the film thickness of the electrode 112 exceeds 100 μm, the electrode 112 becomes a constraining surface with respect to the piezoelectric element 111, and there is a possibility that the energy conversion efficiency is lowered. In the direct embodiment, the side surface of the laminate of the piezoelectric element 111 and the electrode 112 is covered with the resin 115.

  The vibration member 114 vibrates due to vibration generated from the piezoelectric element 111. The vibrating member 114 adjusts the fundamental resonance frequency of the piezoelectric element 111. The fundamental resonance frequency of the mechanical vibrator depends on the load weight and compliance. Since the compliance is the mechanical rigidity of the vibrator, the basic resonance frequency of the piezoelectric element 111 can be controlled by controlling the rigidity of the vibration member 114. The thickness of the vibration member 114 is preferably 5 μm or more and 500 μm or less. The vibration member 114 preferably has a longitudinal elastic modulus, which is an index indicating rigidity, of 1 GPa or more and 500 GPa or less. When the rigidity of the vibration member 114 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 vibration member 114 is not particularly limited as long as it is a material having a high elastic modulus with respect to the piezoelectric element 111 that is a brittle material, such as metal or resin, but phosphor bronze, Stainless steel or the like is preferable.

  The waterproof member 121 is made of, for example, a resin material. The waterproof member 121 vibrates due to vibration generated from the piezoelectric element 111 together with the vibration member 114. The thickness of the waterproof member 121 is, for example, 5 μm or more and 200 μm or less.

  The support member 130 protrudes from the waterproof member 121 at the end facing the housing 510. For this reason, even if the support member 130 is attached to the inner surface of the housing 510, the waterproof member 121 does not contact the inner surface of the housing 510.

  In this embodiment, the waterproof member 121 is joined to the support member 130 on the entire circumference. However, the joint between the waterproof member 121 and the support member 130 may have a gap that does not allow water to penetrate due to surface tension.

  In the present embodiment, the oscillation device 100 includes a second vibration member 114 and a second waterproof member 121 on the other surface side of the piezoelectric element 111. That is, the second vibrating member 114 is located on the opposite side of the first vibrating member 114 with the piezoelectric element 111 interposed therebetween, and one surface is attached to the piezoelectric element 111. The second waterproof member 121 has a sheet shape and is attached to the other surface of the second vibration member 114. The second waterproof member 121 has a planar shape larger than that of the second vibration member 114 and is made of a waterproof material. The outer periphery of the second waterproof member 121 is also joined to the support member 130. In the present embodiment, the two waterproof members 121 have the same shape, and the two vibration members 114 have the same shape.

  The electronic device 500 includes a control unit 160. The control unit 160 inputs a modulation signal that drives the oscillation device 100 as a parametric speaker to the piezoelectric element 111. However, the control unit 160 may input the amplified audio signal as it is to the oscillation device 100 and cause the oscillation device 100 to function as a normal speaker. In the present embodiment, the control unit 160 is connected to the electrode 112 of the piezoelectric element 111 via the vibration member 114. Note that the oscillation device 100 may be used as a transmission source of a sound wave sensor.

  FIG. 2 is a plan view of the oscillation device 100. In this figure, illustration of one vibration member 114 and the waterproof member 121 is abbreviate | omitted for description. In the example shown in this figure, the planar shape of each member constituting the oscillation device 100 is a quadrangle, for example, a square or a rectangle. However, the shape of the oscillation device 100 is not limited to this.

  Next, the operation and effect of this embodiment will be described. According to this embodiment, the area inside the sound hole 511 is separated from other areas by the support member 130 and the waterproof member 121. Therefore, even if water permeates from the sound hole 511, the permeated water remains in the space surrounded by the support member 130 and the waterproof member 121. Therefore, the waterproof performance of the electronic device 500 having the sound hole 511 can be improved.

  The waterproof member 121 has a sheet shape. In other words, the vibration member of the oscillation device 100 is configured by a laminated body of the vibration member 114 and the waterproof member 121 from a different viewpoint. And the edge part of this vibration member is comprised by the waterproof member 121 rich in a softness | flexibility. Therefore, the mechanical quality factor of the oscillation device 100 can be reduced. Thereby, the frequency dependence of the output of the oscillation apparatus 100 can be reduced.

  The piezoelectric element 111 is attached to the support member 130 via a resin waterproof member 121. For this reason, even if an impact is applied to the electronic device 500, the impact is absorbed to some extent by the waterproof member 121 before being transmitted to the piezoelectric element 111. Therefore, the impact resistance of the oscillation device 100 is improved.

  In addition, the end of the support member 130 on the side facing the housing 510 protrudes from the waterproof member 121. For this reason, when the support member 130 is attached to the inner surface of the housing 510, the waterproof member 121 can be prevented from contacting the inner surface of the housing 510. For this reason, it can suppress that the oscillation efficiency of the oscillation apparatus 100 falls.

  The piezoelectric element 111, the electrode 112, and the vibration member 114 are surrounded by the support member 130 and the two waterproof members 121. For this reason, even if moisture enters the inside of the housing 510 from other portions of the housing 510, it is possible to suppress the moisture from adversely affecting the piezoelectric element 111, the electrode 112, or the vibration member 114.

  The control unit 160 is connected to the piezoelectric element 111 via the vibration member 114. For this reason, since it is not necessary to join the wiring directly to the electrode 112 of the piezoelectric element 111, the working efficiency at the time of mounting is improved.

(Second Embodiment)
FIG. 3 is a cross-sectional view illustrating a configuration of an electronic device 500 according to the second embodiment, and corresponds to FIG. 1 in the first embodiment. The electronic device 500 according to the present embodiment has the same configuration as the electronic device 500 according to the first embodiment, except for the configuration of the waterproof member 121.

  In the present embodiment, the waterproof member 121 has an adjustment part 122 in part. The adjustment part 122 differs in at least one of a material and thickness with respect to the main body of the waterproof member 121. The oscillation characteristic of the oscillation device 100 can be adjusted by adjusting at least one of the material and thickness of the adjustment unit 122.

  Also according to this embodiment, the same effect as that of the first embodiment can be obtained. Further, by adjusting at least one of the material and the thickness of the adjustment unit 122, the oscillation characteristics of the oscillation device 100 can be adjusted.

(Third embodiment)
FIG. 4 is a plan view showing the configuration of the oscillation device 100 according to the third embodiment, and corresponds to FIG. 2 in the first embodiment. The oscillation device 100 according to the present embodiment has the same configuration as that of the oscillation device 100 according to the first embodiment, including a method for incorporating the electronic device 500, except that a beam 116 is provided on the vibration member 114. is there.

  The beam portion 116 is formed by projecting a part of the outer peripheral portion of the vibration member 114 outward. The end portion of the beam portion 116 is joined to the inner surface of the support member 130. In the example shown in this figure, the vibration member 114 has beam portions 116 at two positions on the outer periphery facing each other.

  Also according to this embodiment, the same effect as that of the first embodiment can be obtained. In addition, since the vibration member 114 is fixed to the support member 130 by the beam portion 116, the stress caused by the vibration of the vibration member 114 can be concentrated on the beam portion 116, and the vibration of the vibration member 114 can be increased.

  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. For example, in each of the embodiments described above, the two vibrating members 114 have the same shape and thickness, but at least one of the shapes and thicknesses of the two vibrating members 114 may be different from each other. Similarly, at least one of the shapes and thicknesses of the two waterproof members 121 may be different from each other.

DESCRIPTION OF SYMBOLS 100 Oscillator 111 Piezoelectric element 112 Electrode 114 Vibration member 115 Resin 116 Beam part 121 Waterproof member 122 Adjustment part 130 Support member 160 Control part 500 Electronic device 510 Housing | casing 511 Sound hole

Claims (6)

A vibrating member;
A piezoelectric element attached to one surface of the vibration member;
A sheet-like waterproof member that is attached to the other surface of the vibration member, has a planar shape that is the same as or more than the vibration member, and is made of a waterproof material;
A support member joined to the outer periphery of the waterproof member;
An oscillation device comprising: The oscillation device according to claim 1,
The support member is an oscillation device in which an end portion located on a side opposite to the vibration member protrudes from the waterproof member. The oscillation device according to claim 1 or 2,
The oscillation device in which the support member is joined to the entire outer periphery of the waterproof member. In the oscillation device according to any one of claims 1 to 3,
A second vibration member that is located on the opposite side of the vibration member via the piezoelectric element, and one surface is attached to the piezoelectric element;
A sheet-like second waterproofing member attached to the other surface of the second vibrating member, and having a planar shape larger than the second vibrating member and made of a waterproof material;
Have
An oscillation device in which an outer periphery of the waterproof member is joined to the support member. A housing,
A sound hole provided in the housing;
An oscillation device provided in a position facing the sound hole in the housing;
With
The oscillator is
A vibrating member;
A piezoelectric element attached to one surface of the vibration member;
A sheet-like waterproof member that is attached to the other surface of the vibration member, has a planar shape larger than the vibration member, and is made of a waterproof material;
A support member joined to the outer periphery of the waterproof member;
Have
The support device is an electronic device that is joined to an inner surface of the casing so as to surround the sound hole in a direction in which the waterproof member faces the sound hole. The electronic device according to claim 5,
Electronic equipment comprising control means for inputting a modulation signal for driving the oscillation device as a parametric speaker to the piezoelectric element.

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