JP7203637B2 - Actuator and speaker device - Google Patents

Description

The disclosed embodiments relate to actuators and speaker devices.

2. Description of the Related Art Conventionally, there has been known an actuator that utilizes the so-called inverse piezoelectric effect, which is the volume distortion of a piezoelectric element due to voltage application (see, for example, Patent Document 1). Such an actuator is attached to the back surface of a panel such as a display, for example, and can be driven to vibrate the panel so that the panel can function as a diaphragm of a speaker.

JP 2014-127794 A

However, the conventional techniques described above have room for further improvement in terms of improving the vibration characteristics of the panel.

For example, in the conventional technology described above, the panel is vibrated by bending the panel so as to follow the expansion and contraction of the piezoelectric element due to volumetric strain. loss is likely to occur, and vibration of the opposite phase is likely to occur. Therefore, when the panel functions as a speaker device, for example, the sound pressure frequency characteristics are degraded.

One aspect of the embodiments has been made in view of the above, and an object thereof is to provide an actuator and a speaker device capable of improving vibration characteristics of a panel.

An actuator according to an aspect of an embodiment is an actuator provided on a panel, and includes a diaphragm, a piezoelectric element, and a vibration transmission section. The piezoelectric element is provided on at least one main surface of the diaphragm. The vibration transmitting section is connected to the diaphragm on both sides of the piezoelectric element in the short side direction of the central portion in the long side direction of the piezoelectric element in a plan view of the diaphragm, and is in contact with the panel. touch.

According to one aspect of the embodiment, the vibration characteristics of the panel can be improved.

FIG. 1 is a schematic front view showing an overview of the configuration of a display speaker according to a comparative example. FIG. 2 is an explanatory diagram of the driving principle of the piezoelectric element. FIG. 3 is an explanatory diagram of operation of the panel according to the comparative example. FIG. 4 is a schematic front view showing the outline of the configuration of the display speaker according to the first embodiment. FIG. 5 is a schematic front view of the actuator according to the first embodiment. FIG. 6 is a schematic bottom view of the actuator according to the first embodiment. FIG. 7 is a schematic side view of the actuator according to the first embodiment. FIG. 8 is a diagram showing an arrangement example of actuators according to the first embodiment. FIG. 9 is an operation explanatory diagram of the actuator according to the first embodiment. FIG. 10 is a dimension explanatory diagram of the vibration transmitting portion according to the first embodiment. 11A and 11B are diagrams (part 1) illustrating an example of attachment of the vibration transmitting portion according to the first embodiment; FIG. FIG. 12 is a diagram (part 2) illustrating an example of mounting the vibration transmitting portion according to the first embodiment; FIG. 13 is a diagram showing the configuration of a vibration transmitting section according to a first modified example. FIG. 14 is a diagram showing the configuration of a vibration transmitting section according to a second modification. FIG. 15 is a diagram showing the configuration of a vibration transmitting section according to a third modification. FIG. 16 is a schematic side view showing the outline of the configuration of the actuator according to the second embodiment. FIG. 17 is a schematic front view showing the outline of the configuration of the display speaker according to the third embodiment.

Hereinafter, embodiments of an actuator and a speaker device disclosed in the present application will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

In the following description, the actuator is provided in a display panel such as an organic EL (organic electro-luminescence) display that does not require a backlight, and the display functions as a display speaker. A display speaker corresponds to an example of a speaker device.

In addition, each drawing used in the following description may show a three-dimensional orthogonal coordinate system in order to make the description easier to understand. In such an orthogonal coordinate system, the main surface direction of plate-like members such as a panel, a piezoelectric element, and a diaphragm, which will be described later, is the XY plane direction, and the thickness direction of these plate-like members is the Z-axis direction.

The term “principal surface” refers to the front and back main surfaces of the plate-like member, excluding the side surfaces along the thickness direction of the plate-like member. point to In the following description, the front direction is defined as viewed from the positive direction of the Z axis.

(First embodiment)
First, the first embodiment will be described, but prior to that, an overview of the configuration of a display speaker 10' according to a comparative example will be described. FIG. 1 is a schematic front view showing an overview of the configuration of a display speaker 10' according to a comparative example. FIG. 2 is an explanatory diagram of the driving principle of the piezoelectric element PZ. Note that FIG. 2 exaggerates the thickness of the piezoelectric element PZ. Moreover, FIG. 3 is an operation explanatory diagram of the panel P according to the comparative example.

As shown in FIG. 1, a display speaker 10' according to the comparative example includes a panel P and a piezoelectric element PZ. The panel P is, for example, a display panel of an organic EL display.

The piezoelectric element PZ is a so-called piezoelectric element, and is based on an element in which a piezoelectric body such as a specific ceramic is sandwiched between two electrodes, and has various structures such as a unimorph type.

In the display speaker 10' according to the comparative example, for example, two such piezoelectric elements PZ are provided on the rear surface of the panel P, and are attached at symmetrical positions with respect to the entire surface of the panel P. As shown in FIG. The display speaker 10' vibrates the panel P using a phenomenon in which a piezoelectric body deforms when a voltage is applied to the piezoelectric element PZ, the so-called inverse piezoelectric effect, and outputs sound using the panel P as a diaphragm.

Specifically, as shown in FIG. 2, the piezoelectric element PZ is pre-polarized in the Z-axis direction, which is the thickness direction, for example. expands and contracts in the direction of polarization, and the thickness increases and decreases.

However, since the volume does not change, for example, when the piezoelectric element PZ expands in the polarization direction (see arrow 201 in the figure), it contracts in the X-axis direction perpendicular to the polarization direction (see arrow 202 in the figure). Also, when the piezoelectric element PZ contracts in the polarization direction (see arrow 203 in the figure), it expands in the X-axis direction perpendicular to the polarization direction (see arrow 204 in the figure).

In the display speaker 10' according to the comparative example, the piezoelectric element PZ that expands and contracts in this way is attached to the back surface of the panel P as described above, but the panel P itself does not expand and contract. Therefore, as shown in FIG. 3, the expansion and contraction of the piezoelectric element PZ (see arrows 301 and 302 in the drawing) acts as a force that bends the entire panel P that does not expand and contract. That is, the difference in expansion and contraction between the piezoelectric element PZ and the panel P causes the panel P to vibrate.

However, when the panel P is vibrated by bending the panel P to follow the expansion and contraction of the piezoelectric element PZ in this way, loss is likely to occur in the way the vibration is transmitted, and vibration of the opposite phase is likely to occur. Therefore, according to the display speaker 10' according to the comparative example, the cancellation of the sound due to the anti-phase vibration tends to cause deterioration of the sound pressure frequency characteristics.

Therefore, the display speaker 10 according to the first embodiment vibrates the panel P using the actuator 11 . The actuator 11 includes a diaphragm 111 , a piezoelectric element PZ, and a vibration transmission section 112 .

Diaphragm 111 is arranged such that its main surface is substantially parallel to the rear surface of panel P. As shown in FIG. The piezoelectric element PZ is provided on at least one main surface of the diaphragm 111 . The vibration transmitting portion 112 is provided so as to extend from the vibration plate 111 without contacting the piezoelectric element PZ and contact the rear surface of the panel P. As shown in FIG.

A specific configuration example of the display speaker 10 according to the first embodiment will be described below with reference to FIGS. 4 to 12. FIG. FIG. 4 is a schematic front view showing the outline of the configuration of the display speaker 10 according to the first embodiment. Also, FIG. 5 is a schematic front view of the actuator 11 according to the first embodiment. Also, FIG. 6 is a schematic bottom view of the actuator 11 according to the first embodiment.

Also, FIG. 7 is a schematic side view of the actuator 11 according to the first embodiment. FIG. 8 is a diagram showing an arrangement example of the actuators 11 according to the first embodiment. Moreover, FIG. 9 is an operation explanatory diagram of the actuator 11 according to the first embodiment.

Moreover, FIG. 10 is a dimension explanatory drawing of the vibration transmission part 112 which concerns on 1st Embodiment. 11 and 12 are diagrams (part 1) and (part 2) showing examples of attachment of the vibration transmitting portion 112 according to the first embodiment.

As shown in FIG. 4 , the display speaker 10 according to the first embodiment has an actuator 11 . One actuator 11 is provided on the back surface of the panel P, for example, at the central portion.

Specifically, the actuator 11 includes a vibration plate 111, a piezoelectric element PZ, and a vibration transmission section 112, as shown in FIGS. Diaphragm 111 is, for example, a plate-like member whose longitudinal direction is the Y-axis direction and whose lateral direction is the X-axis direction, and is made of glass epoxy or the like.

The piezoelectric elements PZ are provided, for example, on both main surfaces of the diaphragm 111 along the extending direction of the diaphragm 111, as shown in FIGS. The piezoelectric element PZ is attached to the vibration plate 111 using an adhesive material such as an adhesive, double-sided tape, or the like.

The diaphragm 111 is provided so that the area of its main surface is larger than the area of the main surface of the piezoelectric element PZ. Therefore, as shown in FIG. 5, in the state where the piezoelectric element PZ is provided, the vibration plate 111 has a non-contact area with the piezoelectric element PZ (hereinafter referred to as a "margin area") around the piezoelectric element PZ. ) is formed.

Vibration transmitting portion 112 is provided on the main surface of diaphragm 111 on the side facing the rear surface of panel P so as to extend from the margin area and contact the rear surface of panel P. As shown in FIG. For example, as shown in FIGS. 5 and 6, the vibration transmitting portion 112 is formed in a bridge shape, in other words, in a substantially U-shape in a vertical cross-sectional view along the XZ plane. One is provided in

As shown in FIGS. 5 and 6, the vibration transmitting portion 112 is formed in a bridge shape, and is composed of three members, for example, a horizontal portion 112a and a pair of leg portions 112b.

Moreover, as shown in FIG. 7 , the actuator 11 further includes a pair of support portions 113 . The supporting portion 113 is a member that supports the diaphragm 111, and is provided in marginal regions at both ends in the longitudinal direction (Y-axis direction) of the main surface of the diaphragm 111 opposite to the side on which the vibration transmitting portion 112 is provided. provided respectively.

As shown in FIG. 8, the actuator 11 is provided so as to be interposed between the chassis C and the panel P of the display speaker 10, and the support portion 113 is made of an adhesive material such as an adhesive or double-sided tape. It is attached to the chassis C using On the other hand, the vibration transmitting portion 112 is provided so as to come into contact with the rear surface of the panel P, as indicated by M1 in the drawing.

In the actuator 11 arranged in this manner, as shown in FIG. 9, the piezoelectric elements PZ provided on both sides of the main surface of the diaphragm 111 are arranged such that the phases are opposite to each other when driven. A voltage is applied. That is, the pair of piezoelectric elements PZ is driven so that when one expands along the Y-axis direction, the other contracts along the Y-axis direction (see arrows 901 and 902 in the drawing). .

As a result, the vibration plate 111 can be made more flexible following the expansion and contraction of the piezoelectric element PZ, and the driving force of the actuator 11 can be increased.

In addition, since the vibration transmitting portion 112 is in contact with the back surface of the panel P, the expansion and contraction of the piezoelectric element PZ along the longitudinal direction (Y-axis direction) is transmitted in the perpendicular direction (Z-axis direction). The vibration is converted into vibration and transmitted to the rear surface of the panel P (see arrow 903 in the figure).

In other words, the vibration transmission unit 112 concentrates the vibrations that are converted in the vertical direction by the diaphragm 111 bending in response to the expansion and contraction of the piezoelectric element PZ at the central part of the diaphragm 111 and transmits the vibration to the rear surface of the panel P. introduce.

As a result, occurrence of opposite-phase vibrations in the panel P can be reduced. That is, the sound pressure frequency characteristics of the panel P can be improved.

As shown in FIG. 10, the height dimension h of the vibration transmitting portion 112 is set so as not to contact the piezoelectric element PZ even when the piezoelectric element PZ reaches the maximum displacement position. As a result, it is possible to prevent transmission of vibration to the panel P from being hindered due to contact between the vibration transmitting portion 112 and the piezoelectric element PZ during driving.

Note that, as shown in FIG. 11, the vibration transmitting portion 112 can be attached to the diaphragm 111 using an adhesive material A such as an adhesive, double-sided tape, or the like. Alternatively, as shown in FIG. 12, the vibration transmitting portion 112 can be attached to the diaphragm 111 by fitting, for example.

In FIG. 12, the leg portions 112b of the vibration transmitting portion 112 are formed so as to expand, for example, in the free state, and are fitted into the fitting holes 111a formed in advance in the diaphragm 111, whereby the vibration transmitting portion 112 is attached to the diaphragm 111. FIG.

(Modification of Vibration Transmitting Part 112)
Next, modified examples of the vibration transmitting portion 112 will be described with reference to FIGS. 13 to 15. FIG. FIG. 13 is a diagram showing the configuration of a vibration transmitting portion 112A according to a first modified example. Also, FIG. 14 is a diagram showing the configuration of a vibration transmitting portion 112B according to a second modified example. Also, FIG. 15 is a diagram showing a configuration of a vibration transmitting portion 112C according to a third modified example.

So far, an example has been shown in which the vibration transmitting portion 112 is composed of three members, a horizontal portion 112a and a pair of leg portions 112b. 112 A of vibration transmission parts which concern can be comprised as one bridge|bridging member. According to the vibration transmitting portion 112A according to the first modified example, it is possible to suppress the loss of vibration transmission caused by errors in the combination processing of a plurality of members.

Further, until now, the vibration transmitting portions 112 and 112A are formed in a substantially U-shape when viewed in longitudinal section on the XZ plane, and are in surface contact with the panel P, for example, by the horizontal portion 112a. is not.

For example, as shown in FIG. 14, a vibration transmitting portion 112B according to the second modified example is formed to have a substantially arch shape when viewed in longitudinal section along the XZ plane. That is, the vibration transmitting portion 112B may be formed such that the top portion that contacts the rear surface of the panel P has an R shape and is in point contact with the rear surface of the panel P. As shown in FIG.

As a result, the vibration transmitting section 112B can intensively transmit the vibration to the point P1 in the figure, which is in point contact with the point P1. .

Moreover, although the example in which the vibration transmitting portions 112, 112A, and 112B are formed in a bridge shape has been described so far, the present invention is not limited to this.

For example, as shown in FIG. 15, the vibration transmitting portion 112C according to the third modification has a plurality of protrusions protruding from the diaphragm 111, and each of the protrusions has an R-shaped tip. FIG. 15 shows an example in which the vibration transmitting portion 112C is in point contact with the rear surface of the panel P at points P2 and P3.

As a result, the vibration transmitting portion 112C can intensively transmit vibrations to the point-contact points P2 and P3, which can contribute to, for example, accurately transmitting the vibration of the low-frequency component of the sound. In addition, the vibration transmitting portion 112C can transmit stable and concentrated vibrations through a plurality of point contacts.

14 and 15, the vibration transmitting portions 112B and 112C are in point contact with the rear surface of the panel P, but they may be in surface contact.

As described above, the actuator 11 according to the first embodiment is an actuator provided on the panel P, and includes the vibration plate 111, the piezoelectric element PZ, and the vibration transmission portions 112, 112A, 112B, and 112C. . The piezoelectric element PZ is provided on at least one main surface of the diaphragm 111 . Vibration transmitting portions 112, 112A, 112B, and 112C are provided on diaphragm 111 and abut against the back surface of panel P without contacting piezoelectric element PZ.

Therefore, according to the actuator 11 according to the first embodiment, the vibration characteristics of the panel P can be improved.

The piezoelectric elements PZ are provided on both main surfaces of the diaphragm 111, and voltages are applied to the two surfaces so that the phases are opposite to each other during driving. Therefore, according to the actuator 11 according to the first embodiment, it is possible to improve the driving force.

At least one vibration transmitting portion 112 is provided in the central portion of the diaphragm 111 . Therefore, according to the actuator 11 according to the first embodiment, the panel P can be efficiently vibrated, and the vibration characteristics of the panel P can be improved.

Also, the vibration transmitting portions 112 and 112A are formed in a substantially U-shape. Therefore, according to the actuator 11 according to the first embodiment, vibration can be efficiently transmitted to the panel P, and the vibration characteristics of the panel P can be improved.

Also, the vibration transmitting portion 112B is formed in a substantially arch shape. Therefore, according to the actuator 11 according to the first embodiment, it is possible to intensively transmit vibrations to the contact point, which contributes to accurate transmission of, for example, vibrations of low-frequency components of sound. . Further, the rigidity of the vibration transmitting portion 112B can be improved due to the substantially arched shape.

Also, the vibration transmitting portion 112</b>C is formed in the shape of a plurality of protrusions protruding from the diaphragm 111 . Therefore, according to the actuator 11 according to the first embodiment, it is possible to intensively transmit vibrations to the contact point, which contributes to accurate transmission of, for example, vibrations of low-frequency components of sound. . In addition, the plurality of point contacts enables stable and concentrated transmission of vibration, and the panel P can be efficiently vibrated without loss, and the vibration characteristics of the panel P can be improved.

Also, the vibration transmitting portion 112 is provided in the center of the diaphragm 111 in the long side direction, and on the short sides of the back side of the vibration transmitting portions 112 and 112A, in other words, at both ends in the longitudinal direction of the vibration transmitting portion 112. A leg portion 112 b is provided on the side facing the diaphragm 111 . Therefore, according to the actuator 11 according to the first embodiment, it is possible to transmit the vibration of the diaphragm 111 to the panel P in a well-balanced manner.

(Second embodiment)
FIG. 16 is a schematic side view showing the outline of the configuration of the actuator 11A according to the second embodiment. So far, an example has been described in which the vibration transmitting portions 112, 112A, 112B, and 112C are in direct contact with the back surface of the panel P, but this is not the only case.

16, the actuator 11A can interpose the cushioning material B between the vibration transmitting portion 112 and the rear surface of the panel P. As shown in FIG. This makes it possible to achieve the effect of preventing chattering, for example.

(Third embodiment)
FIG. 17 is a schematic front view showing the outline of the configuration of the display speaker 10A according to the third embodiment. So far, an example in which one actuator 11, 11A is provided, for example, at the central portion of the back surface of the panel P has been described, but this is not the only option.

That is, as shown in FIG. 17, the display speaker 10A can be provided with actuators 11 and 11A near both ends of the panel P in the longitudinal direction (X-axis direction), respectively.

This allows, for example, stereophonic reproduction of sound. When the display speaker 10A is mounted in the vehicle compartment, for example, by providing the actuators 11 and 11A near both ends of the instrument panel (instrument panel), an effective stereophonic sound is provided to the driver. playback can be provided.

In each of the embodiments described above, the piezoelectric element PZ is provided on both sides of the main surface of the diaphragm 111, but it is sufficient if it is provided on at least one side.

Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the invention are not limited to the specific details and representative embodiments so shown and described. Accordingly, various changes may be made without departing from the spirit or scope of the general inventive concept defined by the appended claims and equivalents thereof.

10, 10A Display speaker 11, 11A Actuator 111 Diaphragm 111a Fitting hole 112, 112A, 112B, 112C Vibration transmission part 112a Horizontal part 112b Leg part 113 Support part A Adhesive material B Cushioning material C Chassis P Panel PZ Piezoelectric element

Claims (8)

An actuator provided on a panel,
a diaphragm;
a piezoelectric element provided on at least one main surface of the diaphragm;
a vibration transmitting portion connected to the diaphragm and in contact with the panel on both sides of the piezoelectric element in the short side direction of the central portion in the long side direction of the piezoelectric element in a plan view of the diaphragm ; An actuator, comprising: The piezoelectric element is
2. The actuator according to claim 1, wherein the actuator is provided on both main surfaces of the diaphragm, and voltages are applied to the two surfaces in opposite phases when driven. The vibration transmitting section is
3. The actuator according to claim 1, wherein at least one is provided in the central portion of said diaphragm. An actuator provided on a panel,
a diaphragm;
a piezoelectric element provided on at least one main surface of the diaphragm;
a substantially U-shaped vibration transmitting portion that is provided on the diaphragm and contacts the panel without contacting the piezoelectric element;
An actuator comprising : An actuator provided on a panel,
a diaphragm;
a piezoelectric element provided on at least one main surface of the diaphragm;
a substantially arch-shaped vibration transmitting portion that is provided on the diaphragm and contacts the panel without contacting the piezoelectric element;
An actuator comprising : The vibration transmitting section is
2. The actuator according to claim 1, wherein the actuator is formed in the shape of a plurality of protrusions protruding from the vibration plate. An actuator provided on a panel,
a diaphragm;
a piezoelectric element provided on at least one main surface of the diaphragm;
a vibration transmitting portion provided on the diaphragm and in contact with the panel without contacting the piezoelectric element;
with
The vibration transmitting section is
An actuator , characterized in that it is provided at the center of the diaphragm in the long side direction, and has legs on the short side of the back side of the vibration transmitting section. the panel;
and the actuator according to any one of claims 1 to 7 provided on the back surface of the panel.

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