Panel type speaker

Abstract

To provide a panel type speaker for reducing damage of a piezoelectric element.SOLUTION: A panel type speaker outputs a sonic wave from a panel by vibrating the panel by an actuator. The actuator includes: a diaphragm; and a piezoelectric element arranged on at least one surface of the diaphragm. The piezoelectric element has an opening from which the diaphragm is exposed at the center part in a plane view. The diaphragm is to be joined with the panel in a part where the diaphragm is exposed from the opening.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a panel type speaker. [Background technology]

[0002] There is a display speaker (panel type speaker) that uses a display as a speaker by vibrating the display panel of the display with an actuator (vibration actuator) that uses a piezoelectric element. In a display speaker, a vibration unit is provided between the vibration actuator and the display panel. The vibration unit is attached, for example, to the back surface of the display panel with double-sided adhesive tape or the like. Furthermore, the vibration unit is attached, for example, to the center of the piezoelectric element of the vibration actuator with double-sided adhesive tape or the like. This allows the vibration unit to transmit the vibration of the vibration actuator to the display panel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-171927 A Summary of the Invention [Problem to be solved by the invention]

[0004] When the piezoelectric element of the vibration actuator attached to the vibration section vibrates, stress is applied to the piezoelectric element, which may cause damage to the piezoelectric element.

[0005] An object of the present invention is to provide a panel-type speaker that reduces damage to a piezoelectric element. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention employs the following solutions. That is, the first aspect is A panel-type speaker that vibrates a panel using an actuator to output sound waves from the panel, The actuator comprises: A diaphragm; A piezoelectric element is disposed on at least one surface of the vibration plate, The piezoelectric element has an opening at the center when viewed from above through which the diaphragm is exposed, and the diaphragm is coupled to the panel at the portion where the diaphragm is exposed through the opening, thereby forming a panel-type speaker. Effect of the Invention

[0007] According to the present invention, it is possible to provide a panel type speaker that reduces damage to a piezoelectric element. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a display speaker 10 according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of the configuration of a vibration actuator 300 according to an embodiment. [Diagram 3] FIG. 3 is a diagram showing an example of the configuration of the display speaker 11 according to the first modification. [Figure 4] FIG. 4 is a diagram showing an example of the configuration of a vibration actuator 300 according to the first modification. [Diagram 5] FIG. 5 is a diagram showing an example of the configuration of the display speaker 12 according to the second modification. [Figure 6] FIG. 6 is a diagram showing an example of the configuration of a vibration actuator 300 according to the second modification. [Figure 7] FIG. 7 is a diagram showing an example of the configuration of a vibration actuator 300 according to the third modification. [Figure 8] FIG. 8 is a diagram showing an example of the configuration of the display speaker 13 according to the fourth modification. [Figure 9] FIG. 7 is a diagram showing an example of the configuration of a vibration actuator 300 according to the fourth modification. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The configurations of the following embodiments are merely examples, and the present invention is not limited to the configurations of the embodiments.

[0010] Here, a case will be described in which a vibration actuator is provided on a display panel of a display, and the display functions as a display speaker. A display speaker is a device that outputs (emits) sound waves from a display panel by vibrating the display panel with a vibration actuator (actuator).

[0011] <Embodiment> (Configuration example) FIG. 1 is a diagram showing an example of the configuration of a display speaker 10 of this embodiment. FIG. 1 is a cross-sectional view of the display speaker 10 seen from above. The display speaker 10 of FIG. 1 includes a display panel 100, an excitation unit 200, and a vibration actuator 300. The excitation unit 200 includes a main body 210, a double-sided adhesive tape 221 on the display panel side, and a double-sided adhesive tape 222 on the vibration actuator side. The vibration actuator 300 includes a diaphragm 310, a piezoelectric element 320 attached to a surface (first surface) of the diaphragm 310 on the display panel side, and a piezoelectric element 330 attached to a surface (second surface) of the diaphragm 310 opposite to the first surface. A plurality of excitation units 200 and vibration actuators 300 may be attached to one display panel 100. Here, the direction from right to left in FIG. 1 is the x-direction, the direction from the back to the front of the paper surface of FIG. 1 is the y-direction, and the direction from bottom to top in FIG. 1 (the direction from the vibration actuator 300 to the display panel 100) is the z-direction. The positional relationship between the display speaker 10 and the x-direction, y-direction, and z-direction is the same in other figures. The display panel 100 is an example of a panel. The display speaker is an example of a panel-type speaker. The vibration actuator 300 is an example of an actuator.

[0012] The display panel 100 is a type of display panel that is included in liquid crystal displays, organic EL (Electro-Luminescence) displays, and the like.

[0013] The excitation unit 200 transmits the vibration of the vibration actuator 300 to the display panel 100. The main body 210 of the excitation unit 200 is, for example, a columnar (for example, a rectangular column, a cylinder, etc.) object, and has an upper surface and a lower surface that are approximately parallel to each other. The excitation unit 200 is, for example, resin, metal, etc. A double-sided adhesive tape 221 is attached to one of the upper surface and the lower surface, and a double-sided adhesive tape 222 is attached to the other surface. Here, it is assumed that the double-sided adhesive tape 221 is attached to the upper surface, and the double-sided adhesive tape 221 is attached to the lower surface. The double-sided adhesive tape 221 attaches and fixes the main body 210 of the excitation unit 200 to the back surface of the display panel 100. The double-sided adhesive tape 222 attaches and fixes the main body 210 of the excitation unit 200 to the diaphragm 310 of the vibration actuator 300. The excitation unit 200 is fixed to the diaphragm 310 without contacting the piezoelectric element 320. The excitation unit 200 is fixed between the display panel 100 and the vibration actuator 300 by double-sided adhesive tapes 221, 222. An adhesive or the like may be used instead of the double-sided adhesive tapes 221, 222. The excitation unit 200 and the display panel 100 may be integrated. The diaphragm 310 of the vibration actuator 300 is coupled to the display panel 100 via the excitation unit 200.

[0014] The vibration plate 310 of the vibration actuator 300 is a rectangular plate-like member, and has a front surface (first surface) and a back surface (second surface) in a direction perpendicular to the thickness direction. The shape may be circular or elliptical. The shape of the diaphragm 310 may be any other shape as long as it is symmetrical from left to right and from top to bottom. The front surface is approximately parallel to the back surface. The diaphragm 310 is arranged so that the front surface of the diaphragm 310 is approximately parallel to the back surface of the display panel 100. The piezoelectric elements 320 and 330 are elements whose shape changes in response to the voltage when a voltage is applied. The piezoelectric elements 320 and 330 are elements made of a plate-shaped material such as ceramic that exhibits a piezoelectric effect. Electrodes for applying a voltage are attached to the piezoelectric elements 320 and 330. The piezoelectric element 320 is attached to the first surface of the diaphragm 310. The piezoelectric element 330 is attached to the second surface of the diaphragm 310. The piezoelectric element 320 has an opening so that the center part of the diaphragm 310 is exposed when viewed from the first surface side. The piezoelectric element 320 has an opening in the center part. The diaphragm 310 has a portion (exposed portion) exposed at the center of the first surface of the diaphragm 310 due to an opening of the piezoelectric element 320. The double-sided adhesive tape 222 of the excitation unit 200 is attached to the opening, thereby bonding the diaphragm 310 and the excitation unit 200. At this time, the piezoelectric element 320 and the excitation unit 200 are not in contact with each other. Note that the piezoelectric element 330 does not have to be attached to the diaphragm 310 (the piezoelectric element 330 does not have to be present). The first surface and the second surface are on the xy plane.

[0015] FIG. 2 is a diagram showing an example of the configuration of the vibration actuator 300 of this embodiment. FIG. 2 is a diagram showing the vibration actuator 300 as viewed from the first surface side. A piezoelectric element 320 having an opening is attached to the first surface of the vibration plate 310 of the vibration actuator 300. In addition, the central part of the vibration plate 310 (part including the center of the first surface, central part in plan view) is exposed by the opening of the piezoelectric element 320. Here, when the shape of the vibration plate 310 is rectangular, the center of the first surface (second surface) of the vibration plate 310 is the intersection point of two diagonals of the rectangle. In addition, when the shape of the vibration plate 310 is circular or elliptical, the center of the first surface (second surface) of the vibration plate 310 is the center of the circle or ellipse. Even if the shape of the vibration plate 310 is another shape, the center of the first surface (second surface) of the vibration plate 310 can be defined by, for example, the center of gravity. The size of the opening of the piezoelectric element 320 (the size of the exposed part of the vibration plate 310) is larger than the size of the lower surface of the main body 210 of the vibration unit 200 attached to the vibration plate 310 (the part surrounded by the dotted line in FIG. 2). This prevents the piezoelectric element 320 from coming into contact with the vibration unit 200. Here, the opening of the piezoelectric element 320 is rectangular (square), but it may be circular to match the shape of the vibration unit 200. In order to increase the area of ​​the piezoelectric element 320, it is desirable to make the size of the opening of the piezoelectric element 320 as small as possible. By increasing the area of ​​the piezoelectric element 320, the output (maximum output) of the display speaker 10 can be increased. In addition, when the vibration actuator 300 is viewed from the first surface side, it is desirable that the outer end of the piezoelectric element 320 is inside the end of the vibration plate 310. If the outer end of the piezoelectric element 320 is outside the end of the vibration plate 310, the piezoelectric element 320 is easily damaged. The same applies to the piezoelectric element 330 attached to the second surface of the diaphragm 310.

[0016] (Variation 1) Here, a first modified example of this embodiment will be described. The first modified example has some points in common with the above-mentioned configuration example. Here, differences from the above-mentioned configuration example will be mainly described.

[0017] FIG. 3 is a diagram showing a configuration example of a display speaker 11 of the first modified example. FIG. 3 is a cross-sectional view of the display speaker 11 viewed from above. The display speaker 11 of FIG. 3 includes a display panel 100, a vibration unit 200, and a vibration actuator 300. The vibration unit 200 includes a main body 210, a double-sided adhesive tape 221 on the display panel side, and a screw 230. The vibration actuator 300 includes a vibration plate 310, a piezoelectric element 320, and a piezoelectric element 330. The vibration plate 310 has a through hole in the center. The center of the through hole coincides with the center of the vibration plate 310. The cross-sectional shape of the through hole is, for example, circular. The vibration unit 200 and the display panel 100 may be integrated.

[0018] Fig. 4 is a diagram showing an example of the configuration of a vibration actuator 300 of Modification 1. Fig. 4 is a diagram showing the vibration actuator 300 as viewed from the first surface side. A through hole for passing a screw 230 is provided in the center of a vibration plate 310 of the vibration actuator 300. An opening is provided in the center of the piezoelectric element 320 so that the through hole of the vibration plate 310 is exposed.

[0019] In the above configuration example, the excitation unit 200 and the vibration actuator 300 are fixed by a double-sided adhesive tape 222. In the first modification, the excitation unit 200 and the vibration actuator 300 are fixed by a screw 230. In the first modification, the vibration plate 310 has a through hole in the center through which the screw 230 passes. The piezoelectric element 330 attached to the second surface of the vibration plate 310 has an opening that exposes the center of the second surface of the vibration plate 310, similar to the piezoelectric element 320. The main body 210 of the excitation unit 200 has a screw hole on the vibration actuator 300 side for fixing the screw 230. When fixing the vibration actuator 300 to the excitation unit 200, the screw 230 is passed through the through hole from the second surface side of the vibration plate 310 and screwed to the main body 210 of the excitation unit 200 on the first surface side. That is, the vibration actuator 300 is connected to the display panel 100 via the vibration unit 200 by the screw 230. This allows for stronger fixing (connection) than when fixed by the double-sided adhesive tape 222. Also, durability is improved compared to when fixed by the double-sided adhesive tape 222. Bolts and nuts may be used instead of the screw 230.

[0020] (Variation 2) Here, a second modification of the present embodiment will be described. The second modification has common points with the above-described configuration example and modifications. Here, differences from the above-described configuration example and modifications will be mainly described.

[0021] FIG. 5 is a diagram showing a configuration example of the display speaker 12 of the second modification. FIG. 5 is a cross-sectional view of the display speaker 12 viewed from above. The display speaker 12 of FIG. 5 includes a display panel 100, an excitation unit 200, and a vibration actuator 300. The excitation unit 200 includes a main body 210, a double-sided adhesive tape 221 on the display panel side, and a screw 230. The vibration actuator 300 includes a vibration plate 310, a piezoelectric element 320, and a piezoelectric element 330. The vibration plate 310 has a through hole in the center. The excitation unit 200 and the display panel 100 may be integrated. As in the first modification, the second modification has a configuration in which the excitation unit 200 and the vibration actuator 300 are fixed by the screw 230. In the second modification, the size of the vibration actuator 300 side of the main body 210 of the excitation unit 200 is reduced in order to increase the area of ​​the piezoelectric element 320. The size of the main body 210 of the excitation unit 200 on the vibration actuator 300 side is large enough to support the screw 230. On the other hand, it is desirable that the size of the main body 210 of the excitation unit 200 on the display panel 100 side is larger. This is because if the area of ​​the adhesive surface between the display panel 100 and the excitation unit 200 becomes small, the possibility that the excitation unit 200 will come off the display panel 100 increases. Here, the main body 210 of the excitation unit 200 is shaped so as not to come into contact with the piezoelectric element 320. The length in the z direction of the main body 210 on the vibration actuator 300 side (the portion that is smaller than the display panel 100 side) is longer than the thickness (length in the z direction) of the piezoelectric element 320. As a result, the excitation unit 200 and the piezoelectric element 320 do not come into contact with each other.

[0022] Fig. 6 is a diagram showing an example of the configuration of a vibration actuator 300 of Modification 2. Fig. 6 is a diagram showing the vibration actuator 300 as viewed from the first surface side. The exposed portion of the diaphragm 310 of the vibration actuator 300 of Modification 2 is smaller than the exposed portion of the diaphragm 310 of Modification 1. Therefore, the area of ​​the piezoelectric element 320 of Modification 2 is larger than the area of ​​the piezoelectric element 320 of Modification 1. This makes it possible to increase the output (maximum output) of the display speaker 10.

[0023] (Variation 3) Here, a third modification of the present embodiment will be described. The third modification has common points with the above-described configuration examples and modifications. Here, differences from the above-described configuration examples and modifications will be mainly described.

[0024] FIG. 7 is a diagram showing a configuration example of a vibration actuator 300 of the third modification. FIG. 7 is a diagram showing the vibration actuator 300 as viewed from the first surface side. In the vibration actuator 300 of the third modification, the piezoelectric element 320 is divided into two piezoelectric elements 320A and 320B. The piezoelectric elements 320A and 320B are attached to the vibration plate 310, avoiding the exposed portion of the vibration plate 310 to which the excitation unit 200 is attached. The piezoelectric elements 320A and 320B are attached to the portion of the vibration plate 310 other than the exposed portion to which the excitation unit 200 is attached. Here, two piezoelectric elements are attached to the first surface of the vibration plate 310, but two or more piezoelectric elements may be attached. This makes it unnecessary to provide an opening in the piezoelectric element 320, and therefore makes it easier to process the piezoelectric element 320. The same is true for the piezoelectric element 330 attached to the second surface of the vibration plate 310.

[0025] (Variation 4) Here, a fourth modified example of the present embodiment will be described. The fourth modified example has common points with the above-mentioned configuration examples and modifications. Here, differences from the above-mentioned configuration examples and modifications will be mainly described.

[0026] FIG. 8 is a diagram showing a configuration example of the display speaker 13 of the fourth modification. FIG. 8 is a cross-sectional view of the display speaker 13 viewed from above. The display speaker 13 of FIG. 8 includes a display panel 100, a vibration unit 200, and a vibration actuator 300. The vibration unit 200 includes a main body 210, a double-sided adhesive tape 221 on the display panel side, a first screw 230A, and a second screw 230B. The vibration actuator 300 includes a vibration plate 310, a piezoelectric element 320, and a piezoelectric element 330. The vibration plate 310 has a first through hole and a second through hole in the center. The center of the first through hole and the center of the second through hole pass through the center of the vibration plate 310 and exist on a straight line parallel to the x direction. The distance from the center of the first through hole to the center of the vibration plate 310 and the distance from the center of the second through hole to the center of the vibration plate 310 are the same. For example, when the distance from the center of the through hole to the center of the diaphragm 310 is shorter than the distance from the center of the through hole to the closest end of the diaphragm 310, the through hole is assumed to be present in the central part of the diaphragm 310. The first and second through holes are present near the center of the diaphragm 310. The excitation unit 200 and the display panel 100 may be integrated. As in the first and second modifications, the fourth modification has a configuration in which the excitation unit 200 and the vibration actuator 300 are fixed by the first screw 230A and the second screw 230B. In the fourth modification, in order to suppress the flexural vibration of the diaphragm 310, the excitation unit 200 and the vibration actuator 300 are fixed by two screws (the first screw 230A and the second screw 230B). Here, it is assumed that a flexural vibration occurs in which the x direction of the diaphragm 310 is bowed in the z direction. 8, a voltage applied to the piezoelectric elements 320 and 330 generates a flexural vibration in which the x direction of the diaphragm 310 bows in the z direction. That is, the flexural vibration propagates in the x direction of the diaphragm 310. Here, a plurality of through holes are provided in the direction along which the flexural vibration of the diaphragm 310 propagates. The vibration of the diaphragm 310 can be more efficiently transmitted to the display panel 100 by the first and second through holes of the diaphragm 310, which pass through the center of the diaphragm 310 and exist on a straight line parallel to the x direction, and the first and second screws 230A and 230B.When a flexural vibration occurs in which the y direction of the diaphragm 310 is curved in the z direction, a first through hole and a second through hole of the diaphragm 310 may be provided on a straight line that passes through the center of the diaphragm 310 and is parallel to the y direction. The vibration actuator 300 may be fixed to the vibration unit 200 by two or more through holes and two or more screws. By fixing at more positions in the propagation direction of the flexural vibration, the vibration mode is dispersed, and the vibration of the diaphragm 310 can be transmitted to the display panel 100 more efficiently over a wide band.

[0027] FIG. 9 is a diagram showing a configuration example of a vibration actuator 300 according to a fourth modified example. This is a view from the first surface side of the actuator 300. The vibration plate 310 of the vibration actuator 300 of Modification 4 has a first through hole and a second through hole on a line that passes through the center of the vibration plate 310 and is parallel to the x direction. The piezoelectric element 320 has openings that expose the first through hole and the second through hole.

[0028] (Actions and Effects of the Embodiments) The display speaker 10 of this embodiment includes a display panel 100, a vibration actuator 200, and a vibration actuator 300. The vibration actuator 300 includes a vibration plate 310, a piezoelectric element 320, and a piezoelectric element 330. The vibration actuator 200 is fixed to the vibration plate 310 without contacting the piezoelectric element 320 and the piezoelectric element 330. According to the display speaker 10, since the vibration actuator 200 does not contact the piezoelectric element 320 and the piezoelectric element 330, damage to the piezoelectric element 320 and the piezoelectric element 330 can be suppressed compared to a configuration in which the piezoelectric element 320 and the piezoelectric element 330 contact the vibration actuator 200. Furthermore, according to the display speaker 10, the vibration actuator 300 and the vibration actuator 200 can be firmly coupled to each other.

[0029] Although the embodiments of the present invention have been described above, these are merely examples, and the present invention is not limited to these. Various modifications based on the knowledge of those skilled in the art are possible without departing from the spirit of the claims. [Explanation of symbols]

[0030] 10 Display Speaker 11 Display Speaker 12 Display Speaker 13 Display Speaker 100 Display Panel 200 Vibration section 210 Main body 221 Double-sided adhesive tape 222 Double-sided adhesive tape 230 Screw 300 Vibration Actuator 310 Diaphragm 320 Piezoelectric element 330 Piezoelectric element

Claims

[Claim 1] A panel-type speaker that vibrates a panel using an actuator to output sound waves from the panel, The actuator comprises: A diaphragm; A piezoelectric element is disposed on at least one surface of the vibration plate, the piezoelectric element has an opening at a central portion in a plan view through which the vibration plate is exposed, The actuator comprises: a plurality of through holes provided in a portion where the diaphragm is exposed by the opening, the through holes penetrating one surface and the other surface of the diaphragm; a plurality of screws passing through each of the plurality of through holes; One of the openings is provided to surround the plurality of through holes, the diaphragm is connected to the panel by the plurality of screws at a portion where the diaphragm is exposed through the opening; A panel-type speaker, wherein the plurality of through holes are provided in a direction along a propagation direction of flexural vibration of the diaphragm.

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