CN1710994A - Piezoelectric loud speaker - Google Patents
Piezoelectric loud speaker Download PDFInfo
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- CN1710994A CN1710994A CN200510077322.7A CN200510077322A CN1710994A CN 1710994 A CN1710994 A CN 1710994A CN 200510077322 A CN200510077322 A CN 200510077322A CN 1710994 A CN1710994 A CN 1710994A
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Abstract
A piezoelectric loudspeaker includes a diaphragm and a piezoelectric element bonded on a principal surface of the diaphragm. An electrode layer is provided on the surface of the piezoelectric element. The piezoelectric element has a structure formed by alternately laminating at least three piezoelectric layers and electrode layers in order to achieve a sufficient driving force. A conductive path composed of a strip-shaped metal foil and having an adhesive layer on the reverse face thereof is provided on the surface of the electrode layer. The adhesive layer may be conductive or nonconductive. Conductive paste having a low rigidity and a low volume resistivity is applied so as to be disposed over the surfaces of the conductive path and the electrode layer. Thus, a conductive layer having a Young's modulus of 100 MPa or less and a volume resistivity of 6x10 -3 Omegacm or less is provided.
Description
Technical field
The present invention relates to a kind of piezoelectric speakers, power loss, acoustic pressure decline, the improvement of audio reproduction more specifically to traveling wave thin piezoelectric loudspeaker.
Background technique
In the past, such as ultrathin piezoelectric speaker of the thickness less than or equal to 1mm uses and is pasted onto the construction of the piezoelectric element (piezoelectrics thin plate) of plate thickness direction polarization in the single or double of metal oscillating plate.In order to obtain enough acoustic pressures, the laminated body for being formed as the piezoelectric element piezoelectrics (piezoelectric layer) and electrode layer has been laminated is needed.For this reason, it may be necessary to fired electrodes simultaneously, as the materials'use silver/palladium alloy electrodes for being able to bear firing.As the conductive path for applying signal for the electrode to piezoelectrics surface, it is less than or equal to the metal foil with electric conductivity adhesives of 0.1mm using thickness to ensure the thickness (such as patent document 1 below) of loudspeaker entirety.In addition, it is effective for reducing the method for the ratio of the palladium in electrode in order to reduce cost, so, by using with low sintering piezoelectrics, making such as silver/palladium ratio 9:1 or so.But for such electrode for reducing palladium amount, due to be contracted in it is lower than the piezoelectrics as base material at a temperature of carry out, so, the stress generated in sintering due to the mismatch of contraction makes piezoelectric element deform or destroy.Therefore, people use the matched method added piezoelectrics material identical with base material in the electrodes, obtain shrinking percentage.
[patent document 1] Japanese Unexamined Patent Publication 2003-078995 bulletin
Summary of the invention
However, the piezoelectrics material being added in electrode as above, is discharged from metal in sintering, so, for the external electrode of piezoelectric element, the particle of piezoelectrics material is precipitated in electrode surface.Since piezoelectrics material sheet is as non-conductor, contact resistance increases because particle is precipitated, and power consumed by contact portion increases.The problem of accordingly, there exist the energy for being efficiently converted into sound to reduce, decrease in efficiency.In addition, in order to avoid the problem, although there is also the areas for increasing conductive path (metal foil), the method for reducing contact resistance, but in the method, since conductive path hinders the vibration of oscillating plate, so there are resonance frequency increase, acoustic pressure declines such problems.In addition, becoming obstacle as idioelectric piezoelectrics material itself, contact of the electric conductivity adhesives with electrode becomes unstable in the case where obtaining electrical contact with electric conductivity adhesives.In this way, contact resistance changes with vibration, there are problems that the reproducibility of sound is significantly damaged.
The present invention is conceived to problem above and makes, and its purpose is to provide a kind of slim piezoelectric speakers for reducing contact resistance with capable of not making tonequality deterioration, reducing power loss.Another object, which is to provide, a kind of forms the good slim piezoelectric speaker of stable status of electrically connecting, audio reproduction.
In order to achieve the above object, piezoelectric speaker of the invention includes the piezoelectric element and the oscillating plate for another main surface side for being pasted onto the piezoelectric element at least one interarea of piezoelectrics with electrode layer；With the conductive path being made of belt metal foil, it is conductively connected the electrode layer of above-mentioned piezoelectric element each other, or it is conductively connected any one layer of electrode layer in above-mentioned piezoelectric element with external circuit, also, the layer of adhesive material by being arranged overleaf is fixed on above-mentioned electrode layer；And the conductive layer formed by coating electrocondution slurry, it is arranged to be connected to the upper surface of above-mentioned conductive path from the surface of above-mentioned electrode layer, Young's modulus is less than or equal to 100MPa, and volume resistivity is less than or equal to 6 × 10-3Ωcm。
One major programme is characterized in that: the contact area and above-mentioned conductive path of above-mentioned electrode layer surface and conductive layer and the contact area of conductive layer are respectively greater than or are equal to 0.8mm2, the thickness of above-mentioned conductive layer is more than or equal to 0.01mm.Another program is characterized in that: above-mentioned electrode layer surface and the contact area of conductive layer are preferably less than or equal to 20mm2.In addition, the diameter of above-mentioned oscillating plate is 10mm~50mm.
Another aspect is characterized in that: (1) being the construction that above-mentioned piezoelectric element has been pasted at least one interarea of above-mentioned oscillating plate；(2) above-mentioned piezoelectric element is the lit-par-lit structure for being alternately laminated multiple piezoelectric layers and electrode layer；(3) above-mentioned piezoelectric element includes at least 3 layers of piezoelectric layer.
The piezoelectric speaker of another invention includes the piezoelectric element and the oscillating plate for another main surface side for being pasted onto the piezoelectric element at least one interarea of piezoelectrics with electrode layer；With the conductive path being made of belt metal foil, in order to make the electrode layer of above-mentioned piezoelectric element carry out being conductively connected each other or be conductively fixed on above-mentioned electrode layer to be conductively connected any one layer of electrode layer in above-mentioned piezoelectric element and external circuit；The back side of above-mentioned conductive path is arranged in electric conductivity layer of adhesive material；And the conductive layer formed by coating electrocondution slurry, it is arranged to be connected to the upper surface of above-mentioned conductive path from the surface of above-mentioned electrode layer；Also, above-mentioned conductive layer is formed as connecting at multiple positions with above-mentioned electrode layer along the edge part of above-mentioned conductive path.Preferably, above-mentioned conductive layer is respectively formed in the two sides of above-mentioned conductive path or form above-mentioned conductive layer with traversing the conductive path.One major programme is characterized in that: the Young's modulus of above-mentioned conductive layer is less than or equal to 100MPa, moreover, volume resistivity is less than or equal to 6 × 10-3Ωcm。
Another program is characterized in that: the contact area and above-mentioned conductive path of above-mentioned electrode layer surface and conductive layer and the contact area of conductive layer are respectively greater than or are equal to 0.8mm2, the thickness of above-mentioned conductive layer is more than or equal to 0.01mm.Another aspect is characterized in that: above-mentioned electrode layer surface and the contact area of conductive layer are preferably less than or equal to 20mm2.In addition, the diameter of above-mentioned oscillating plate is 10mm~50mm.
Another aspect is characterized in that: (1) being the construction that above-mentioned piezoelectric element has been pasted at least one interarea of above-mentioned oscillating plate；(2) above-mentioned piezoelectric element is the lit-par-lit structure for being alternately laminated multiple piezoelectric layers and electrode layer；(3) above-mentioned piezoelectric element includes at least 3 layers of piezoelectric layer.
Above and other purpose, feature and advantage of the invention will be specified by detailed description and accompanying drawings below.
Detailed description of the invention
Figure 1A is the top view of the embodiment 1 of piezoelectric speaker of the invention.
Figure 1B is the perspective view of above embodiment 1.
Fig. 1 C is the perspective view for indicating the back side of conductive path of above embodiment 1.
Fig. 1 D is the top view for indicating the variation of above embodiment 1.
Fig. 1 E is the top view for indicating another variation of above embodiment 1.
Fig. 2 is the major section figure of the piezoelectric speaker of the embodiment of the present invention.
Specific embodiment
In the present invention, according to when using environment and condition may exist multiple suitable embodiments, but illustrate an appropriate number of embodiment herein.
(embodiment 1)
In the following, preferred forms for carrying out the present invention are described in detail according to embodiment.Fig. 1 is the figure for indicating the essential structure of piezoelectric speaker of the invention, Figure 1A is the top view of embodiment 1, Figure 1B is its perspective view, Fig. 1 C is the perspective view for indicating the back side of conductive path, Fig. 1 D is the top view for indicating the variation of embodiment 1, and Fig. 1 E is the top view for indicating another variation of embodiment 1.
As shown in Figure 1, piezoelectric speaker 10 of the invention, the sticking piezoelectric element 14 on metal oscillating plate 12, the piezoelectric element 14 have electrode layer 16 at least one interarea of piezoelectrics.Above-mentioned piezoelectric speaker 10 can be single piezoelectric patches (unimorph) type that above-mentioned piezoelectric element 14 is provided on any one interarea of oscillating plate 12, be also possible to be provided with bimorph (bimorph) type of above-mentioned piezoelectric element 14 on the two sides of oscillating plate 12.In order to make the integral thickness of piezoelectric speaker 10 be less than or equal to 1mm, for example, the thickness of above-mentioned oscillating plate 12 is made to be less than or equal to 0.1mm.In addition, piezoelectric element 14 is using the lit-par-lit structure for the piezoelectric layer for being alternately laminated at least 3 layers with electrode layer, and total thickness is no more than 0.1mm in order to obtain enough driving forces.
The material of the electrode layer 16 of interlayer and surface back side as above-mentioned piezoelectric element 14, such as alloy or silver using silver/palladium=9/1~10/0 ratio (molar ratio) that can be fired simultaneously with piezoelectrics.Electrode layer 16 is to be added in solvent appropriate and form slurry alloy (or silver) and piezoelectrics powder together with binder, then formed on the raw cook (green sheet) of piezoelectrics with such as silk screen print method.It is pasted on the electrode layer 16 on the surface of such piezoelectric element 14 and is overleaf provided with layer of adhesive material 22, belt metal foil of the thickness less than or equal to 0.1mm.The conductive path 20 for making above-mentioned electrode layer 16 be attached or make the electrode layer 16 and external circuit to be attached each other is formed by the metal foil.In the present embodiment, above-mentioned layer of adhesive material 22 is electric conductivity.For this purpose, needing suitably to take and pasting the disposition for insulation such as insulating properties band 23 (C referring to Fig.1) on the part that layer of adhesive material 22 is contacted with oscillating plate 12 with 12 short circuit of oscillating plate in order to prevent.In the present embodiment, using the layer of adhesive material of electric conductivity 22, but dielectric adhesives also can be used.At this point, not needing above-mentioned insulating properties band 23.
Then, from the top of conductive path 20, on the conductive path 20 and the surface of above-mentioned electrode layer 16 applies the electrocondution slurry that rigidity is low, volume resistivity is high, forms conductive layer.The coating shape of electrocondution slurry preferably, can be respectively formed at the two sides of above-mentioned conductive path 20, or be formed as traversing above-mentioned conductive path 20 to connect at multiple positions with above-mentioned electrode layer 16 along the edge part of above-mentioned conductive path 20.For example, piezoelectric speaker 10 that can be as shown in Figure 1A like that, forms 2 circular conductive layers 24, or conductive layer 26 as shown in figure iD is such, is formed as rectangle.When piezoelectric speaker 10 as referring to figure 1E is such, when the position of conductive path 20 is located at by the position at the edge of piezoelectric element 14, although the two sides of conductive path 20 cannot be coated to as the example of above-mentioned Figure 1A or (D), but at this point it is possible to be handled by unilateral side and such 2 positions in front end that circular conductive layer 28 is coated to conductive path 20.
As above-mentioned conductive layer 24,26,28, the conductive paste that rigidity is low, volume resistivity is high is utilized.Specifically, preferably meeting, Young's modulus is less than or equal to 100MPa and volume resistivity is less than or equal to 6 × 10-3The physical property of Ω cm.When Young's modulus is greater than or equal to above-mentioned value, stress when oscillating plate 12 deforms cannot be born and destroyed, or generate the resistance of displacement as oscillating plate 12, therefore lead to tonequality deterioration.For example, table 1 below is an example for indicating the Young's modulus of the electrocondution slurry utilized as conductive layer and having the relationship destroyed caused by the driving for piezoelectric speaker 10 of having no way of.Slurry therewith A is polyester resin, and slurry therewith B is silicon resinoid, and slurry therewith C is epoxylite, and slurry therewith D is polyimide based resin, and any slurry therewith all includes silver as conductive filler.
[table 1]
| Slurry therewith | Young's modulus (MPa) | Volume resistivity (Ω cm) | Filler | Resin | Whether there is or not destructions |
| A | 60 | 1×10-3 | Silver | Polyesters | Nothing |
| B | 600 | 1×10-6 | Silver | Silicon class | Have |
| C | 1000 | 1×10-3 | Silver | Epoxies | Have |
| D | 1400 | 1×10-5 | Silver | Polyimide | Have |
As known from Table 1, using slurry B~D, although meeting volume resistivity less than or equal to 6 × 10-3The condition of Ω cm, but since rigidity is excessively high, so driving causes to destroy.
In addition, showing sound pressure variations in the case where being formed the conductive layer 26 of shape shown in Fig. 1 D as electrocondution slurry and changed the Young's modulus of electrocondution slurry in table 2 below.
[table 2]
| Young's modulus (MPa) | Acoustic pressure deteriorates (dB) |
| 0 (no electrocondution slurry) | 0.00 |
| 50 | -0.05 |
| 100 | -0.10 |
| 200 | -0.22 |
| 500 | -0.43 |
| 1000 | -0.61 |
| 2000 | -0.93 |
| 5000 | -1.49 |
As can be known from the results of Table 2, in order to which acoustic pressure deterioration to be limited within such as 0.1dB, the upper limit of the Young's modulus of electrocondution slurry is 100MPa.It follows that destroying caused by driving in order to prevent, make the deterioration minimum limit of sound quality, the Young's modulus of electrocondution slurry is preferably made to be less than or equal to 100MPa.
In addition, being greater than or equal to 6 × 10 in volume resistivity-3When Ω cm, contact resistance cannot be made sufficiently small.The coating shape of electrocondution slurry can be the arbitrary shapes such as circle, rectangle as long as connecting as described above at multiple positions with above-mentioned electrode layer 16 along the edge part of above-mentioned conductive path 20.But the part both of which for making the part being overlapped with conductive path 20 and being overlapped with electrode layer 16 is greater than or equal to 0.8mm2.For area less than that, the resistance value of electrocondution slurry part ( conductive layer 24,26,28) is not low enough, cannot obtain stable contact condition.In addition, the acoustic pressure in the case that table 3 below shows the electrocondution slurry using Young's modulus 60MPa and changes the surface covered of the electrocondution slurry on electrode layer 16 ( conductive layer 24,26,28) deteriorates.As shown in table 3, it is greater than 20mm in area2In the case where, acoustic pressure is deteriorated more than 0.1dB, therefore, it is preferable to which the surface covered on electrode layer 16 is less than or equal to 20mm2.Influence of the surface covered of such electrocondution slurry to sound matter becomes significant in the case where the diameter of above-mentioned oscillating plate 12 is the more small-sized piezoelectric speaker of 10~50mm or so.This is because the rigidity of oscillating plate 12 increases, so being not easily susceptible to the influence of electrocondution slurry in the case where more small-sized piezoelectric speaker.
[table 3]
| Resin area (mm2) | Acoustic pressure deteriorates (dB) |
| 0 | 0.00 |
| 1 | -0.00 |
| 2 | -0.01 |
| 5 | -0.03 |
| 10 | -0.05 |
| 15 | -0.07 |
| 20 | -0.09 |
| 25 | -0.34 |
As the coating method of above-mentioned electrocondution slurry, such as various methods well known to usable print process, spray coating method etc..In addition, being greater than the thickness of conductive layer 24 (or 26,28) or being equal to 0.01mm (10 μm).If thickness is smaller, resistance value is excessively high, cannot form stable contact condition.By hardening electrocondution slurry with scheduled methods such as ultraviolet light irradiation or heating after coating, the stable piezoelectric speaker 10 of contact condition can get.
(embodiment 1)
In the following, illustrating examples and comparative examples of the present invention.The major section of the piezoelectric speaker of embodiment and comparative example is shown in FIG. 2.Firstly, illustrating embodiment 1.The piezoelectric speaker 30 of embodiment 1 is to be provided with conductive path 46A, the 46B being made of belt metal foil on electrode layer 38A, the 44A on the surface of above-mentioned piezoelectric element 34,40 in the bimorph type of the piezoelectric element 34 and 40 of the surface back side two sides patch laminate construction of oscillating plate 32.The iron-nickel alloy of such as diameter 23mm, thickness 0.03mm are used as above-mentioned oscillating plate 32.Above-mentioned piezoelectric element 34 is the laminated body of alternately laminated 3 lamination electric layer 36A~36C and 4 layers of electrode layer 38A~38D, as above-mentioned piezoelectric layer 36A~36C, such as the lead zirconate titanate using diameter 19mm, thickness 0.018mm (18 μm), as electrode layer 38A~38D, such as use the silver-palladium alloy of diameter 18.5mm, thickness 0.001mm.Above-mentioned electrode layer 38A~38D is connected with each other by through-hole etc..Another piezoelectric element 40 is also construction identical with above-mentioned piezoelectric element 34, for the lit-par-lit structure for being alternately laminated 3 lamination electric layer 42A~42C and 4 layers of electrode layer 44A~44D.
Above-mentioned conductive path 46A, 46B are the copper foil for being overleaf provided with electric conductivity layer of adhesive material 48A, 48B, such as using the copper foil having a size of thick 0.07mm, long 10mm, width 2mm, above-mentioned layer of adhesive material 48A, 48B can also be non-conductive.In addition, short circuit occurs in the part that the metal of above-mentioned 32 peripheral portion of oscillating plate exposes in order to prevent, insulating properties band 50A, 50B are pasted in the inside of above-mentioned conductive path 46A, 46B.And the polyesters electrocondution slurry (ProductName: DW-250H-5, Japan's spinning (strain) system, Young's modulus: 60MPa, volume resistivity: 1 × 10 for being coated with that silver is conductive filler is applied since on such conductive path 46A, 46B-3Ω cm), form conductive layer 52A and 52B.Coating shape is as shown in Figure 1A, forms the circle of diameter 1.0mm at 2 positions with spray coating method, making the area on conductive path 46A (46B) and electrode layer 38A (44A) is respectively 0.9mm2, in addition, conductive layer 52A, 52B with a thickness of 0.015mm.
With the resistance value between electrode layer 38A, the 44A on the surface of conductive path 46A, 46B and piezoelectrics 34,40 of the piezoelectric speaker of 4 terminal methods measurement acquisition, show the result in table 4 below.In addition, being set to the piezoelectric speaker of acquisition on the fixture that periphery is fixed, opposite end give apply voltage be 3Vrms, the sine wave that frequency is 1kHz.Then, collection sound is carried out with sound of the microphone to generation, confirms that the signal being exaggerated by preamplifier, observation waveform have undistorted with oscillograph.It the results are shown in table 4 below.In table 4, the judgement that wave distortion will be present is unstable contact condition, is stable contact condition by the judgement not distorted.
(embodiment 2)
The electrocondution slurry for being the same as in example 1 above condition on conductive path 46A, 46B with print process coating forms rectangular conductive layer 52A, 52B of 1.6 × 4mm as shown in figure iD.Making the area on conductive path 46A (46B) and 3 8A of electrode layer (44A) is respectively 3.2mm2, it is 0.03mm by thickness control.The resistance value between conductive path 46A, 46B and electrode layer 38A, 44A of the piezoelectric speaker produced is measured by the condition being the same as in example 1 above and the presence or absence of the wave distortion of piezoelectric speaker is observed.
(comparative example 1)
The piezoelectric speaker that electrocondution slurry is not used by method identical with above-described embodiment 1 production, i.e., do not form the piezoelectric speaker of conductive layer 52A, 52B, carries out the measurement of resistance value according to the above method and has the observation having no waveform distortion.
(comparative example 2)
In order to be compared with above-described embodiment 2, the Young's modulus of production conductive layer 52A, 52B are 1000MPa, volume resistivity is 2 × 10-3The piezoelectric speaker of Ω cm, thickness 0.02mm carry out the measurement of resistance value according to the above method and have the observation having no waveform distortion.
(comparative example 3)
In order to be compared with above-described embodiment 1, the Young's modulus of production conductive layer 52A, 52B are 40MPa, volume resistivity is 1 × 10-1The piezoelectric speaker of Ω cm carries out the measurement of resistance value according to the above method and has the observation having no waveform distortion.
(comparative example 4)
In order to be compared with above-described embodiment 2, the piezoelectric speaker with a thickness of 0.005mm of conductive layer 52A, 52B are made, the measurement of resistance value is carried out according to the above method and has the observation having no waveform distortion.
About above-described embodiment 1 and 2, comparative example 1~4, table 4 shows the physical property of conductive layer 52A and 52B, coating shape, surface covered, thickness, the presence or absence of the wave distortion of the measured value and piezoelectric speaker of contact resistance between electrode layer 38A, the 44A on the surface of conductive path 46A, 46B and piezoelectric element 34,40 of the piezoelectric speaker produced.
[table 4]
| Young's modulus (MPa) | Volume resistivity (Ω cm) | Apply shape | Area (mm on copper foil2) | Area (mm on electrode2) | Thickness (mm) | Contact resistance (Ω) | Wave distortion | |
| Embodiment 1 | 60 | 1×10-3 | Diameter 1mm × 2 position | 0.9 | 0.9 | 0.015 | 0.11 | Nothing |
| Embodiment 2 | 60 | 1×10-3 | 1.6mm×4 | 3.2 | 3.2 | 0.03 | 0.08 | Nothing |
| Comparative example 1 | Without electrocondution slurry | 4.22 | Have and (does not generate sound) | |||||
| Comparative example 2 | 1000 | 2×10-3 | 1.6mm×4 | 3.2 | 3.2 | 0.02 | 1.86 | Have and (does not generate sound) |
| Comparative example 3 | 40 | 1×10-1 | Diameter 1mm × 2 position | 0.9 | 0.9 | 0.015 | 2.09 | Have |
| Comparative example 4 | 60 | 1×10-3 | 1.6mm×4 | 3.2 | 3.2 | 0.005 | 3.33 | Have |
From the result of the table 4 it is found that in embodiment 1 and embodiment 2, meet present invention provide that condition, that is, the Young's modulus of conductive layer 52A, 52B be less than or equal to 100MPa, volume resistivity be less than or equal to 6 × 10-3The contact area of the contact area of Ω cm, electrode layer 38A (44A) and conductive layer 52A (52B), conductive path 46A (46B) and conductive layer 52 (52B) is respectively greater than or is equal to 0.8mm2, the thickness of conductive layer 52A, 52B are more than or equal to 0.01mm (10 μm), as a result, contact resistance is respectively 0.11 Ω, 0.08 Ω, and unrelated with coating shape.I.e., it is possible to which contact resistance to be kept less than to or is equal to 0.5 Ω, the power loss of signal can be inhibited, realize efficient traveling wave thin piezoelectric loudspeaker.In addition, in above-described embodiment 1 and embodiment 2, it is available it is unrelated with coating shape, do not find result as wave distortion.That is, confirmation the result is that: for stable contact condition.
And observe it is relevant to the contact resistance of comparative example as a result, it has been found that, be not used electrocondution slurry comparative example 1 in, contact resistance be 4.22 Ω, very greatly.In addition, the comparative example 3 for being compared with embodiment 1, although Young's modulus meets above-mentioned condition, volume resistivity is bigger than above-mentioned condition, and contact resistance becomes 2.09 Ω.Comparative example 2 for being compared with above-described embodiment 2, although thickness and volume resistivity meet above-mentioned condition, Young's modulus is bigger than above-mentioned condition, and contact resistance becomes 1.86 Ω.Equally, the comparative example 4 for being compared with embodiment 2, although Young's modulus and volume resistivity meet above-mentioned condition, thickness ratio 0.01mm is thin, and contact resistance is 3.33 Ω.It can be seen that the piezoelectric speaker produced for the condition outside by above range from above result, contact resistance both greater than or is equal to 1 Ω, and the power loss of the part increases.
In addition, from comparative example to there is the relevant result that has no waveform distortion can be seen that other than generating wave distortion not generate sound also for the comparative example 1 that electrocondution slurry is not used.In addition, physical property, thickness for change electrocondution slurry, the comparative example 2~4 produced outside the range of above-mentioned condition all occur wave distortions, fail to obtain good audio reproduction.Especially using comparative example 2 of the high electrocondution slurry of Young's modulus, electrocondution slurry is destroyed due to vibration, does not generate sound.
In this way, for the piezoelectric speaker by least on an interarea there is the piezoelectric element of electrode layer and oscillating plate to constitute, by carrying out above-mentioned electrode layer each other or the connection of electrode layer and external circuit by the conductive path that constitutes of belt metal foil for being overleaf provided with layer of adhesive material, also, conductive layer is formed the upper surface of from the surface of above-mentioned electrode layer to above-mentioned conductive path using the electrocondution slurry low, that volume resistivity is high of rigidity.For this purpose, low contact resistance (e.g., less than or equal to 0.5 Ω) is kept in which can not make tonequality deterioration, the power loss of anti-stop signal obtains high-efficient slim piezoelectric speaker.
In addition, for the piezoelectric speaker by least on an interarea there is the piezoelectric element of electrode layer and oscillating plate to constitute, pass through the conductive path being made of the belt metal foil of overleaf conductive layer of adhesive material, carry out above-mentioned electrode layer each other or electrode layer and external circuit connection, and, conductive layer is formed the upper surface of from the surface of above-mentioned electrode layer to above-mentioned conductive path using the electrocondution slurry low, that volume resistivity is high of rigidity, so that connecting at multiple positions with above-mentioned electrode layer along the edge part of above-mentioned conductive path.Thus, form the low conductive path of resistance value, so, even if in the electrode material using low cost, and in the case where the piezoelectrics particle that electrode layer surface becomes barrier layer is precipitated because of sintering, contact resistance value will not change because of vibration, can form stable status of electrically connecting, can get cheap, the good slim piezoelectric speaker of audio reproduction.
The present invention has multiple embodiments, can be variously changed according to above disclosure.For example, also including the following embodiments and the accompanying drawings.
(1) material and shape shown in above-described embodiment, having a size of an example, in the case where obtaining same effect, can suitably change.Such as, above-mentioned conductive layer 24,26,28, the coating shape of 52A, 52B are an example, as long as connecting at multiple positions with above-mentioned electrode layer 16 along the edge part of conductive path, coating shape can also be suitably changed in the range of above-mentioned condition (area, thickness).In addition, for example the conductive layer being formed on the electrode layer of a piezoelectric element can also be made different from the shape of conductive layer on the electrode layer for being formed in another piezoelectric element in the case where piezoelectric speaker is bimorph type.
(2) stacking number of piezoelectric layer and electrode layer can also change as needed.In the above-described embodiments, in order to obtain enough driving forces, still if the total thickness of laminated body is no more than 0.1mm, more layers might as well be laminated in 3 lamination electric layer of stacking.In addition, the connecting structure etc. of interior electrode layer also can according to need and suitably change.
(3) in the above-described embodiments, the layer of adhesive material of electric conductivity is utilized as layer of adhesive material 48A, 48B, but also can use dielectric layer of adhesive material.
(4) as preferred application examples of the invention, there is the loudspeaker of the various electronic equipments such as portable phone (including PHS), portable information terminal (PAD), recorder, PC (personal computer).Certainly, various other purposes are equally applicable to.
As described above, according to the present invention it is possible to keep low contact resistance with not making tonequality deterioration, high efficiency is realized in the loss of anti-stop signal, alternatively, stable status of electrically connecting is obtained, so, it is applicable to slim piezoelectric speaker.In particular it is preferred that being less than or equal to the ultrathin piezoelectric speaker of 1mm for thickness.
It is self-evident, it without departing from the spirit and scope of this invention, may be constructed wide variety of embodiment, the present invention is not restricted in addition to being limited by claim by its particular implementation.
Claims (16)
1. a kind of piezoelectric speaker, the oscillating plate including the piezoelectric element at least one interarea of piezoelectrics with electrode layer and another main surface side for being pasted onto the piezoelectric element；Characterized by possessing
The conductive path being made of belt metal foil, it is conductively connected the electrode layer of above-mentioned piezoelectric element each other, or it is conductively connected any one layer of electrode layer in above-mentioned piezoelectric element with external circuit, also, the layer of adhesive material by being arranged overleaf is fixed on above-mentioned electrode layer；And
The conductive layer formed by coating electrocondution slurry is arranged to be connected to the upper surface of above-mentioned conductive path from the surface of above-mentioned electrode layer, and Young's modulus is less than or equal to 100MPa, and volume resistivity is less than or equal to 6 × 10-3Ωcm。
2. piezoelectric speaker according to claim 1, it is characterised in that:
The contact area and above-mentioned conductive path of above-mentioned electrode layer surface and conductive layer and the contact area of conductive layer are respectively greater than or are equal to 0.8mm2, the thickness of above-mentioned conductive layer is more than or equal to 0.01mm.
3. piezoelectric speaker according to claim 2, it is characterised in that:
Above-mentioned electrode layer surface and the contact area of conductive layer are less than or equal to 20mm2。
4. piezoelectric speaker according to claim 1, it is characterised in that:
The diameter of above-mentioned oscillating plate is 10mm~50mm.
5. piezoelectric speaker according to claim 1, it is characterised in that:
It is the construction that above-mentioned piezoelectric element has been pasted at least one interarea of above-mentioned oscillating plate.
6. piezoelectric speaker according to claim 1, it is characterised in that:
Above-mentioned piezoelectric element is the lit-par-lit structure for being alternately laminated multiple piezoelectric layers and electrode layer.
7. piezoelectric speaker according to claim 6, it is characterised in that:
Above-mentioned piezoelectric element includes at least 3 layers of piezoelectric layer.
8. a kind of piezoelectric speaker, the oscillating plate including the piezoelectric element at least one interarea of piezoelectrics with electrode layer and another main surface side for being pasted onto the piezoelectric element；Characterized by possessing
The conductive path being made of belt metal foil is conductively fixed on above-mentioned electrode layer to be conductively connected the electrode layer of above-mentioned piezoelectric element each other or be conductively connected any one layer of electrode layer and external circuit in above-mentioned piezoelectric element；
The back side of above-mentioned conductive path is arranged in electric conductivity layer of adhesive material；And
The conductive layer formed by coating electrocondution slurry, is arranged to be connected to the upper surface of above-mentioned conductive path from the surface of above-mentioned electrode layer；
Also, above-mentioned conductive layer is formed as connecting at multiple positions with above-mentioned electrode layer along the edge part of above-mentioned conductive path.
9. piezoelectric speaker according to claim 8, it is characterised in that:
It is respectively formed above-mentioned conductive layer in the two sides of above-mentioned conductive path, or form above-mentioned conductive layer with traversing the conductive path.
10. piezoelectric speaker according to claim 8, it is characterised in that:
The Young's modulus of above-mentioned conductive layer is less than or equal to 100MPa, and volume resistivity is less than or equal to 6 × 10-3Ωcm。
11. piezoelectric speaker according to claim 8, it is characterised in that:
The contact area and above-mentioned conductive path of above-mentioned electrode layer surface and conductive layer and the contact area of conductive layer are respectively greater than or are equal to 0.8mm2, the thickness of above-mentioned conductive layer is more than or equal to 0.01mm.
12. piezoelectric speaker according to claim 11, it is characterised in that:
Above-mentioned electrode layer surface and the contact area of conductive layer are less than or equal to 20mm2。
13. piezoelectric speaker according to claim 8, it is characterised in that:
The diameter of above-mentioned oscillating plate is 10mm~50mm.
14. piezoelectric speaker according to claim 8, it is characterised in that:
It is the construction that above-mentioned piezoelectric element has been pasted at least one interarea of above-mentioned oscillating plate.
15. piezoelectric speaker according to claim 8, it is characterised in that:
Above-mentioned piezoelectric element is the lit-par-lit structure for being alternately laminated multiple piezoelectric layers and electrode layer.
16. piezoelectric speaker according to claim 15, it is characterised in that:
Above-mentioned piezoelectric element includes at least 3 layers of piezoelectric layer.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004181815A JP2006005800A (en) | 2004-06-18 | 2004-06-18 | Piezoelectric speaker |
| JP181815/2004 | 2004-06-18 | ||
| JP181816/2004 | 2004-06-18 |
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| Publication Number | Publication Date |
|---|---|
| CN1710994A true CN1710994A (en) | 2005-12-21 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200510077322.7A Pending CN1710994A (en) | 2004-06-18 | 2005-06-20 | Piezoelectric loud speaker |
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| Country | Link |
|---|---|
| JP (1) | JP2006005800A (en) |
| CN (1) | CN1710994A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8319396B2 (en) | 2005-12-27 | 2012-11-27 | Nec Corporation | Piezo-electric actuator and electronic device |
| CN105637898A (en) * | 2014-09-26 | 2016-06-01 | 京瓷株式会社 | Sound generator, sound generating device, and electronic apparatus |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20100138931A (en) * | 2008-03-21 | 2010-12-31 | 엔지케이 인슐레이터 엘티디 | Piezoelectric/electrostrictive element and manufacturing method thereof |
| JP5637521B2 (en) | 2011-11-29 | 2014-12-10 | 住友理工株式会社 | Polymer speaker |
| KR102277583B1 (en) * | 2019-08-23 | 2021-07-13 | 김철희 | loudspeaker apparatus of acoustic guitar |
-
2004
- 2004-06-18 JP JP2004181815A patent/JP2006005800A/en active Pending
-
2005
- 2005-06-20 CN CN200510077322.7A patent/CN1710994A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8319396B2 (en) | 2005-12-27 | 2012-11-27 | Nec Corporation | Piezo-electric actuator and electronic device |
| CN105637898A (en) * | 2014-09-26 | 2016-06-01 | 京瓷株式会社 | Sound generator, sound generating device, and electronic apparatus |
| CN105637898B (en) * | 2014-09-26 | 2019-04-26 | 京瓷株式会社 | Sound producer, flexible piezoelectric sound-generating devices and electronic equipment |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2006005800A (en) | 2006-01-05 |
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