Panel type speaker

Abstract

To provide a technology capable of appropriately setting a resonance frequency of an actuator.SOLUTION: A panel speaker for outputting sound waves from a panel by vibrating the panel with the use of an actuator comprises: a vibration transmission part which has one end connected to the panel and the other end connected to the actuator so as to transmit vibration of the actuator to the panel; and a binding part which binds the actuator to the vibration transmission part. The actuator comprises: a diaphragm; and a piezoelectric element which is disposed at least on one surface of the diaphragm. In order that a resonance frequency of flexural vibration propagating in a specific direction in a diaphragm plane may be a predetermined frequency, a length of a portion of the binding part along the specific direction is set to a predetermined length.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] There is a display speaker (panel type speaker) that makes a display into a speaker by vibrating a display panel of the display with an actuator (vibration actuator) using a piezoelectric element. In the display speaker, a vibration transmission part is provided between the vibration actuator and the display panel. The vibration transmission part is attached, for example, to the back surface of the display panel with double-sided adhesive tape or the like. Further, the vibration transmission part is attached, for example, to the central part of the piezoelectric element of the vibration actuator with double-sided adhesive tape or the like. Thereby, the vibration transmission part can transmit the vibration of the vibration actuator to the display panel.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When vibrating a display panel with a vibration actuator, due to the resonance between the vibration actuator and the display panel, the sound pressure at a specific frequency (resonance frequency) may become strong. As a display speaker, it is desirable to obtain appropriate frequency characteristics over the entire output frequency band rather than having some frequencies stand out. However, the resonance frequency is ultimately determined by the surrounding configuration such as the size of the vibration actuator, the size of the display panel, and the housing of the display panel, and it has been difficult to adjust it arbitrarily.

[0005] The present invention aims to provide a technology capable of appropriately setting the resonance frequency of an actuator.

Means for Solving the Problem

[0006] To solve the above problems, the panel type speaker of the present invention is a panel type speaker that vibrates a panel by an actuator and outputs sound waves from the panel, a vibration transmission part having one end connected to the panel and the other end connected to the actuator, and transmitting the vibration of the actuator to the panel, a restraint part that restrains the actuator to the vibration transmission part, and the actuator includes a diaphragm, and a piezoelectric element disposed on at least one surface of the diaphragm, the restraint part is configured such that the length of a portion of the restraint part along the specific direction is set to a predetermined length so that the resonance frequency of the flexural vibration propagating in a specific direction within the plane of the diaphragm becomes a predetermined frequency.

Effect of the Invention

[0007] According to the present invention, it is possible to provide a technology capable of appropriately setting the resonance frequency of an actuator.

Brief Description of the Drawings

[0008]

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Mode for Carrying Out the Invention

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

[0010] Here, a panel type speaker that vibrates a panel by an actuator and outputs sound waves from the panel will be described. In the following embodiments, mainly an example will be described in which an actuator vibrates a display panel to output (emit) sound waves from the display panel and function as a display speaker.

[0011] 〈First Embodiment〉 (Configuration Example) FIG. 1 is a diagram showing a configuration example of the display speaker 10 of the present embodiment. FIG. 1 is a cross-sectional view of the display speaker 10 viewed from above, FIG. 2 is a view of the actuator viewed from the display side (front side), FIG. 3 is a view of the actuator viewed from the back side, and FIG. 4 is an exploded perspective view of the vibration transmission unit 200. The display speaker 10 in FIG. 1 includes a display panel 100, a vibration transmission unit 200, a vibration actuator 300, and a restraint unit 400. Here, the direction from right to left in FIG. 1 is the x direction, the direction from the back surface to the front surface of the paper in 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. Note that this direction is shown for convenience of explanation and is not limited to this direction. For example, the posture of the display speaker 10 is not limited to this direction. 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. The mounting structure of the actuator in the present embodiment includes a vibration transmission unit 200, a vibration actuator 300, and a restraint unit 400.

[0012] The display panel 100 is a display element included in, for example, a liquid crystal display, an organic EL (Electro-Luminescence) display, etc., and displays and outputs an image when an image signal is input. The display panel 100 is generally flat, and the actuator 300 is connected to the surface (back surface) opposite to the display surface (front surface) of the image via the vibration transmission unit 200. The display panel 100 is an example of a target panel that is vibrated by the vibration actuator 300.

[0013] One end of the vibration transmission unit 200 is connected to the display panel 100, and the other end is the vibration actuator It is connected to the vibrator 300 and transmits the vibration of the vibrator 300 to the display panel 100. The vibration transmission unit 200 has a screw receiving part 210 (a part to be fastened) and a vibration transmission main body 220 provided around the screw receiving part 210. The screw receiving part 210 is erected on the back surface 101 of the display panel 100, and a female screw part 215 to which a restraint part 400 is attached is provided on the free end side thereof.

[0014] The vibration transmission main body 220 has a generally rectangular parallelepiped outer shape in which a display side contact surface 221 in contact with the back surface of the display panel 100 and an actuator side contact surface 222 in contact with the vibrator 300 are provided in parallel, and has a hole 223 penetrating the screw receiving part 210. As long as the vibration transmission main body 220 has the display side contact surface 221 and the actuator side contact surface 222, it may have other outer shapes. For example, it may be columnar such as a quadrangular prism or a cylinder. The vibration transmission unit 200 is made of, for example, resin, metal, or the like.

[0015] In this embodiment, the screw receiving part 210 which is a part of the vibration transmission unit 200 is formed integrally with the display panel 100. However, the present invention is not limited to this, and the vibration transmission unit 200 may be formed separately from the display panel 100, and the vibration transmission unit 200 may be fixed to the display panel 100 with an adhesive or a double-sided tape.

[0016] The vibrator 300 includes a diaphragm 310, a piezoelectric element 320 attached to the surface of the diaphragm 310 on the display panel side (referred to as the first surface), and a piezoelectric element 330 attached to the surface of the diaphragm 310 on the opposite side of the first surface (referred to as the second surface). The diaphragm 310 of the vibrator 300 is coupled to the display panel 100 via the vibration transmission unit 200.

[0017] The diaphragm 310 of the vibration actuator 300 is a rectangular plate-shaped member in plan view, and has a surface (first surface) disposed on the display panel side and a back surface (second surface) on the opposite side. The shape of the diaphragm 310 may be circular or elliptical. Also, the shape of the diaphragm 310 may be other shapes as long as it is symmetric about the left and right and symmetric about the top and bottom. The surface is substantially parallel to the back surface. Also, the diaphragm 310 is arranged such that the surface of the diaphragm 310 is substantially parallel to the back surface of the display panel 100.

[0018] The piezoelectric elements 320 and 330 are piezoelectric elements that deform in shape according to a voltage when a voltage is applied. The piezoelectric elements 320 and 330 are, for example, elements made of a plate-shaped material such as a ceramic exhibiting 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 such that the central portion of the diaphragm 310 is exposed when viewed from the first surface side. The piezoelectric element 320 has an opening in the central portion. The diaphragm 310 has a portion (exposed portion) exposed at the central portion of the first surface of the diaphragm 310 due to the opening of the piezoelectric element 320. The actuator-side contact surface of the vibration transmission portion 200 is connected to the opening. At this time, the piezoelectric element 320 and the vibration transmission portion 200 do not contact each other. Note that a configuration in which one of the piezoelectric elements 320 and 330 is omitted may be employed. In the present embodiment, the first surface and the second surface are on the xy plane.

[0019] FIG. 2 is a view of the vibration actuator 300 as seen from the first surface side. Piezoelectric elements 320 and 330 having openings are attached to the first surface and the second surface of the diaphragm 310 of the vibration actuator 300. Further, the central portion of the diaphragm 310 (the portion including the centers of the first surface and the second surface, the central portion in plan view) is exposed by the openings of the piezoelectric elements 320 and 330. Here, when the shape of the diaphragm 310 is rectangular, the center of the first surface (second surface) of the diaphragm 310 is the intersection of the two diagonals of the rectangle. Also, when the shape of the diaphragm 310 is circular or elliptical, the center of the first surface (second surface) of the diaphragm 310 is the center of the circle or ellipse. Even if the shape of the diaphragm 310 is other shapes, the center of the first surface (second surface) of the diaphragm 310 can be defined by, for example, the center of gravity or the like.

[0020] The size of the opening of the piezoelectric element 320 (the size of the exposed portion of the diaphragm 310) is larger than the size of the actuator-side contact surface 222 of the vibration transmission portion 200 that abuts on the diaphragm 310 (the portion surrounded by the dotted line in FIG. 2). Thereby, the piezoelectric element 320 and the vibration transmission portion 200 do not come into contact. Here, the opening of the piezoelectric element 320 is rectangular (square), but it may be circular according to the shape of the vibration transmission portion 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.

[0021] The size of the opening of the piezoelectric element 330 (the size of the exposed portion of the diaphragm 310) is larger than the area where the restraint portion 400 is arranged (the portion surrounded by the dotted line in FIG. 3). Thereby, the piezoelectric element 330 and the restraint portion 400 do not come into contact. Here, the opening of the piezoelectric element 330 is rectangular (rectangular), but it may be circular according to the shape of the restraint portion 400. In order to increase the area of the piezoelectric element 330, it is desirable to make the size of the opening of the piezoelectric element 330 as small as possible.

[0022] By increasing the areas of the piezoelectric elements 320 and 330, the output (maximum output) of the display speaker 10 can be made larger. Further, when the vibration actuator 300 is viewed from the first surface and the second surface sides, it is desirable that the outer ends of the piezoelectric elements 320 and 330 are inside the ends of the diaphragm 310.

[0023] In addition, a through-hole 311 for passing the restraining portion 400 is provided near the center of the diaphragm 310.

[0024] The restraining portion 400 is a bolt (fastening member) having a male screw portion 410 and a head portion 420. In the examples of FIGS. 1 and 3, two restraining portions 400 are used, and the male screw portion 410 penetrates the through-hole 311 from the second surface side of the diaphragm 310 and is screwed into the female screw portion 215 of the vibration transmission portion 200 until the head portion 420 abuts against the second surface of the diaphragm 310. Thereby, the vibration transmission portion 200, the vibration actuator 300, and the restraining portion 400 are fastened. That is, the vibration actuator 300 is restrained by the restraining portion 400.

[0025] In the present embodiment, on the surfaces (first surface and second surface) of the diaphragm 310 where the piezoelectric elements 320 and 330 are provided, the direction along the longitudinal direction is defined as a specific direction (x direction), and the restraining length L1 (the length from the end of the restraining portion to the opposite end in the specific direction) by the two restraining portions 400 is set to be a predetermined length. This predetermined length is adjusted so that the resonance frequency of the flexural vibration propagating in a specific direction in the plane of the diaphragm 310 becomes a predetermined frequency. For example, a screw receiving portion 210 is provided at a position where the restraining length L1 by the restraining portion 400 becomes a predetermined length. is provided.

[0026] As a result, even if the actuator 300 resonates with the display panel 100 or the like and the sound at a specific resonance frequency is enhanced, the resonance frequency can be set to an appropriate value so that the balance is achieved across the entire frequency band of the sound output from the display panel 100. That is, instead of the sound at some frequencies being prominent, appropriate frequency characteristics can be obtained. For this reason, the resonance frequency can be set only by the length L1 of the restraint portion without changing the sizes of the display panel 100 and the vibration actuator 300, and appropriate frequency characteristics can be obtained with a simple configuration. For example, by setting the resonance frequency high, high-pitched sound reproduction can be enabled while ensuring sound pressure.

[0027] Also, when adjusting the resonance frequency in this specific direction, for example, the restraint length L1 by the restraint portion 400 is set so that the resonance frequency of the flexural vibration propagated in the x direction (first direction) of the diaphragm approaches the resonance frequency of the flexural vibration propagated in the y direction (second direction) orthogonal to this x direction. It may be set.

[0028] As a result, even better frequency characteristics can be obtained across the entire frequency band of the sound output from the display panel 100.

[0029] (Modification 1) FIG. 5 is a diagram showing a holding structure of the actuator according to Modification 1. In this modification, the direction of restraint by the restraint portion 400 is different from that of the above-described embodiment. Since other configurations are the same as those of the above-described embodiment, the same reference numerals are given to the same elements, and repeated description is omitted.

[0030] In the foregoing embodiment, the longitudinal direction of the diaphragm 310 is set as a specific direction, and the resonance frequency in this direction is adjusted. However, in this modified example, the short-side direction of the diaphragm 310 is set as the specific direction, and the resonance frequency in this direction is adjusted. That is, in this modified example, the two restraint portions 400 are arranged in the y direction along the surfaces (the first surface and the second surface) of the diaphragm 310 where the piezoelectric elements 320 and 330 are provided. Therefore, although not shown in the figure, the screw receiving portions 210 that are fastened to these restraint portions 400 are also arranged in the y direction. And the restraint length L2 by this restraint portion 400 is set to be a predetermined length. This predetermined length means that the resonance frequency when the diaphragm 31 0 bends and vibrates in the y direction is adjusted to be a predetermined frequency.

[0031] Thereby, the resonance frequency when the diaphragm 310 of the actuator 300 bends and vibrates in the y direction can be set to an appropriate value.

[0032] (Modified Example 2) FIG. 6 is a diagram showing a holding structure of the actuator according to the modified example 2, and FIG. 7 is a diagram of the vibration transmission portion 200A according to the modified example 2 as viewed from the actuator side. This modified example has a different configuration in which the restraint portion 400 restrains in a plurality of directions as compared with the foregoing embodiment. Since the other configurations are the same as those of the foregoing embodiment, the same reference numerals are given to the same elements, and the repeated description is omitted.

[0033] In the foregoing embodiment, the configuration is such that the resonance frequency in the longitudinal direction (the first direction) of the diaphragm 310 is adjusted. However, in this modified example, in addition to this, the resonance frequency in the short-side direction (the second direction) of the diaphragm 310 is adjusted. For this reason, in this modified example, as shown in FIG. 7, the first screw receiving portion (the portion to be fastened) 211 of the vibration transmission portion 200A is provided at two positions in the x direction (the first direction), and the second screw receiving portion 212 is provided at two positions in the y direction (the second direction). And the restraint portion 400 is fastened to these screw receiving portions 210 (211, 212), respectively.

[0034] Here, the restraint length (first length) L1 by the restraint portion 400 in the x direction and the restraint length (second length) L2 by the restraint portion 400 in the y direction are set so that the resonance frequency when the diaphragm 310 bends and vibrates in the x direction or the y direction is a predetermined value, similar to the above-described embodiments and Modification 1.

[0035] Thereby, the resonance frequency of the actuator 300 in the x direction can be set to an appropriate value, and the resonance frequency in the y direction can be set to an appropriate value. For example, even when the diaphragm has a shape close to a square having sides of substantially the same length in the x direction and the y direction, or a shape close to a perfect circle having diameters of substantially the same length in the x direction and the y direction, by making the restraint length L1 and the restraint length L2 different lengths, the resonance frequencies in the x direction and the y direction can be made different frequencies. Thereby, the sound output from the display panel 100 does not concentrate on a specific frequency, and good frequency characteristics can be obtained over the entire frequency band.

[0036] Further, the restraint portion (fastening member) 400 may be selectively fastened to the first screw receiving portion 211 arranged in the x direction or the second screw receiving portion 212 arranged in the y direction.

[0037] Thereby, the restraint direction can be selected, and the resonance frequency in the x direction and the resonance frequency in the y direction can be selectively adjusted. Therefore, even when connecting the actuator 300 of the same specification to the display panel 100 having different aspect ratios, the frequency characteristics can be appropriately set. For this reason, the actuators 300 adopted for different products can be made common, and for example, the procurement of the actuator 300 can be facilitated.

[0038] (Modification 3) FIG. 8 is a diagram showing a holding structure of the actuator according to Modification 3, and FIG. 9 is a view of the vibration transmission part 200B according to Modification 3 as seen from the actuator side. This modification is different from the above-described embodiment in that the restraint length L1 by the restraint part 400 can be adjusted. Since other configurations are the same as those of the above-described embodiment, the same reference numerals are given to the same elements, and the description will not be repeated.

[0039] In the above-described embodiment, the restraint part 400 was provided at two locations in a specific direction (x direction) of the diaphragm 310. However, in this modification, as shown in FIG. 9, the vibration transmission part 200B includes screw receivers 210 (21-1 to 21-5) at five locations in a specific direction (x direction), and the restraint part 400 is selectively fastened to two of these locations. Note that the number of screw receivers 210 is not limited to this, and may be three or more.

[0040] According to this modification, by adjusting the restraint length by the restraint part 400 that fastens to the five screw receivers 21-1 to 21-5, the resonance frequency in the x direction can be arbitrarily adjusted. For example, compared with the case where the restraint part 400 is fastened to the screw receivers 21-2 and 21-4, when the restraint part 400 is fastened to the screw receivers 21-1 and 21-5, the restraint length becomes longer and the resonance frequency can be set higher.

[0041] Thereby, the resonance frequency can be arbitrarily adjusted according to the usage environment of the display speaker 10, the user's preference, etc. Further, even when connecting an actuator 300 of the same specification to display panels 100 having different sizes and aspect ratios, an optimal restraint length can be selected according to the size of the display panel 100, etc., and the frequency characteristics can be appropriately set. For this reason, the actuators 300 adopted for different products can be made common, and for example, the procurement of the actuator 300 can be facilitated.

[0042] In addition, when arranging the screw receivers 210 in the x-direction and the y-direction as in the aforementioned Modification 2, this modification may be applied, and the screw receivers 210 may be provided at three or more locations in each of the x-direction and the y-direction so that the restraint length can be adjusted in the x-direction and the y-direction.

[0043] <Second Embodiment> FIG. 10 is a diagram showing a holding structure of an actuator according to the second embodiment, and FIG. 11 is a diagram of the holding structure of the actuator according to the second embodiment as viewed from the back side. In this embodiment, compared with the aforementioned first embodiment, the restraint portion 401 includes a fastening member 430 and a spacer 440, and the configuration in which the restraint length is set by the width (length) of the spacer 440 is different. Since other configurations are the same as those of the aforementioned embodiments, the same reference numerals are given to the same elements, and repeated explanations are omitted.

[0044] The spacer 440 is a flat plate-like member and has a through hole 441 through which the fastening member 430 passes in the thickness direction (z-direction in the figure). The spacer 440 is formed of a synthetic resin or metal and has a configuration capable of restraining the diaphragm 310.

[0045] In the display panel 100 of this embodiment, one screw receiver 210 is erected at the center of the back surface. Similarly, a through hole 311 through which the fastening member 430 passes is provided at one location in the center of the diaphragm 310.

[0046] Then, as shown in FIGS. 10 and 11, the male screw portion 410 of the fastening member 430 passes through the through hole 441 and the through hole 311 of the diaphragm 310 from the back side of the spacer 440, and is screwed into the female screw portion 215 of the screw receiver 210 until the head portion 420 abuts against the back surface of the spacer 440. Thereby, the vibration transmission portion 200, the vibration actuator 300, the spacer 440, and the fastening member 430 are fastened. That is, the vibration actuator 300 is restrained by the spacer 440 of the restraint portion 401.

[0047] In this embodiment, the length L1 in the first direction (x direction) and the length L2 in the second direction (y direction) of the spacer 440 provided along the surface (second surface) on which the piezoelectric element 330 of the vibration plate 310 is provided are set to predetermined lengths, respectively.

[0048] According to this embodiment, the resonant frequency of the actuator 300 in the x direction can be set to an appropriate value, and the resonant frequency in the y direction can also be set to an appropriate value, depending on the lengths L1 and L2 of the spacer 440. For example, a plurality of types of spacers having different lengths L1 and L2 can be used. The resonant frequency in the x and y directions may be adjusted by preparing spacers 440 and selecting spacers 440 that provide the desired resonant frequency.

[0049] As a result, even when connecting actuators 300 of the same specifications to display panels 100 of different sizes and aspect ratios, it is possible to select the optimum constraint length and appropriately set the frequency characteristics according to the size of the display panel 100. This allows the actuators 300 used in different products to be standardized, making it easier to procure the actuators 300, for example.

[0050] (Variation 4) Fig. 12 is a diagram showing the actuator holding structure according to Modification 4, and Fig. 13 is a diagram showing the actuator holding structure according to Modification 4 as viewed from the rear side. This modification differs from the second embodiment described above in that a plurality of fastening members 430 are provided in the restraint section 402. Note that other configurations are the same as those in the embodiment described above, and therefore the same elements are denoted by the same reference numerals, and repeated description will be omitted.

[0051] In this modified example, similar to the example of FIG. 1, two screw receivers 210 are erected near the center of the back surface of the display panel 100, and fastening members 430 are respectively fastened to the screw receivers 210. The fastening member 430 has a male screw portion 410 that penetrates through the through hole 441 from the back surface side of the spacer 440 and the through hole 311 of the diaphragm 310, and is screwed into the female screw portion 215 of the screw receiver 210 until the head portion 420 abuts against the back surface of the spacer 440.

[0052] Thereby, the vibration transmission part 200, the vibration actuator 300, the spacer 440, and the fastening member 430 are fastened. That is, the vibration actuator 300 is restrained by the spacer 440 of the restraint part 402.

[0053] According to this modified example, similar to the aforementioned second embodiment, the lengths L1 and L2 of the spacer 440 are used to set the resonance frequencies of the actuator 300 in the x - direction and y - direction, and appropriate frequency characteristics can be obtained. Thereby, for example, when the display speaker 10 of the first embodiment and the actuator 300 are made common, and it is desired to set a resonance frequency other than the frequency determined by the restraint length by the restraint part 400 as in the first embodiment, a spacer 440 may be added as in this modified example, and the resonance frequency may be set by the lengths L1 and L2 of the spacer 440.

[0054] The embodiments of the present invention have been described above, but these are merely examples, and the present invention is not limited thereto. Various modifications based on the knowledge of those skilled in the art are possible without departing from the spirit of the claims.

Explanation of Reference Numerals

[0055] 10 Display speaker 100 Display panel 200 Vibration transmission part 300 Vibration actuator 310 Diaphragm 320 Piezoelectric element 330 Piezoelectric element

Claims

1. A panel-type speaker that vibrates a panel by an actuator to output sound waves from the panel, comprising: a vibration transmission part having one end connected to the panel and the other end connected to the actuator, for transmitting the vibration of the actuator to the panel; a restraint part for restraining the actuator to the vibration transmission part; wherein the actuator comprises: a diaphragm; a piezoelectric element disposed on at least one surface of the diaphragm; wherein the restraint part comprises a fastening member for fastening to the vibration transmission part and a flat spacer, the spacer is abutted against a surface of the diaphragm opposite to the surface connected to the vibration transmission part, and the fastening member is fastened to the vibration transmission part via the spacer, and the length of a portion of the restraint part along the specific direction is defined by the length of the spacer so that the resonance frequency of the flexural vibration propagating in a specific direction within the plane of the diaphragm becomes a predetermined frequency. A panel-type speaker.

2. The panel-type speaker according to claim 1, wherein the diaphragm is rectangular in plan view, and the specific direction is a direction along the longitudinal direction of the diaphragm in plan view.

3. The panel-type speaker according to claim 2, wherein the length of a portion of the restraint part along the specific direction is set to a predetermined length so that the resonance frequency of the flexural vibration propagating in the specific direction approaches the frequency of the flexural vibration propagating in a direction orthogonal to the specific direction.

4. The restraint part comprises a fastening member for fastening to the vibration transmission part, the diaphragm is restrained to the vibration transmission part by the fastening members provided at least at two positions in the specific direction, and the length of the restraint part is defined by the interval between the fastening members in the specific direction. The panel-type speaker according to any one of claims 1 to 3.

5. When the diaphragm has a first direction as the specific direction and a second direction orthogonal to the first direction in plan view, The panel-type speaker according to any one of claims 1 to 4, wherein the length of the restraint part in the second direction is set to a second length so that the resonance frequency of the flexural vibration propagating in the second direction within the plane of the diaphragm becomes a predetermined frequency.

6. ​ The panel type speaker according to claim 5, which cites claim 4, wherein the vibration transmission part includes fastened members to which the fastening member is fastened at at least two locations in the first direction and at least two locations in the second direction, and the restraint direction can be selected by selectively fastening the fastening member to the fastened member in the first direction or the fastened member in the second direction.

7. The panel type speaker according to any one of claims 1 to 6, wherein the vibration transmission part includes fastened members to which the fastening member is fastened at three or more locations in the specific direction, and the length of the restraint is set by the interval between the fastening members fastened to two of the fastened members.

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