JP5907285B2 - Flat speaker and AV equipment - Google Patents

Description

  The present invention relates to a flat speaker having a small thickness with respect to the size of a vibration surface.

  In recent years, the demand for thin speakers has been increasing for reasons such as mounting on thin displays. For this reason, various planar speakers (thin speakers) have been devised.

  The speaker described in Patent Document 1 has a structure in which electrodes are formed on both main surfaces of flat-plate polyvinylidene fluoride (PVDF).

  However, such a conventional flat speaker has a weak point that the sound quality characteristic is generally inferior because a depth cannot be obtained like a dynamic speaker.

  In order to improve this weak point, for example, in the speaker of Patent Document 2, a flat membrane made of resin or the like is vibrated by an electromagnetic exciter (actuator). In the speaker of Patent Document 2, an electromagnetic exciter is attached to the side surface of the membrane.

  In the speaker of Patent Document 3, two flat plates are arranged at a predetermined interval, and an electromagnetic exciter (actuator) is arranged in a hollow region between the flat plates, and the flat plate is vibrated by the exciter.

JP 2009-272978 A JP-A-62-73898 JP 2005-117217 A

  In the speaker shown in Patent Document 2 described above, an electromagnetic exciter is provided on the side of the membrane, so that the shape becomes larger as the exciter is arranged.

  Moreover, in the speaker shown in Patent Document 3, an exciter is disposed between the flat plates, so that at least the thickness of the exciter is required. Furthermore, since the exciters are arranged at opposite ends of the flat plate, the area of the flat plate surface is increased by at least two exciters.

  Accordingly, it is an object of the present invention to provide a flat speaker that is thin and excellent in sound quality characteristics, has a substantially large vibration surface area, and is significantly thinner than the area.

  The planar speaker of the present invention includes a piezoelectric film, an exciter film, a diaphragm, a frame, and a connecting portion. The piezoelectric film is made of a piezoelectric resin having electrodes formed on both main surfaces. An exciter film consists of a flat plate with a piezoelectric film mounted on at least one main surface. The diaphragm is a flat plate disposed at a predetermined interval in a direction orthogonal to the main surface of the exciter film. The frame is formed in a smaller area than the main surfaces of the exciter film and the diaphragm, and is disposed between the exciter film and the diaphragm. The connecting portion connects the end of the exciter film, the end of the frame, and the end of the diaphragm, and propagates the expansion and contraction of the exciter film to the diaphragm with the end of the frame as a fulcrum.

  In this configuration, when a sound signal is applied to the piezoelectric film, the exciter film expands and contracts according to the sound signal. The connecting portion propagates the expansion and contraction of the exciter film to the diaphragm using the end of the film as a fulcrum. Therefore, the diaphragm vibrates according to the sound signal and emits sound to the outside. At this time, the piezoelectric film, exciter film, diaphragm, and frame are all significantly thinner than the main surface area, so that they can be formed thin as a flat speaker. In addition, since the vibration of the piezoelectric film is amplified by the exciter film and propagated to the diaphragm, the sound quality characteristics can be improved.

Moreover, it is preferable that the connection part of the planar speaker of this invention is provided with the 1st joint part and 2nd joint part which consist of the following structure. The first joint portion connects the end portion of the exciter film and the end portion of the frame. The second joint portion connects the end portion of the frame and the end portion of the diaphragm. The first joint part and the second joint part are connected at substantially right angles.

  In this configuration, the first joint portion and the second joint portion are connected in a substantially L shape when viewed in a direction parallel to the main surface of the exciter film, the diaphragm, and the frame. Thereby, the connection part becomes a fulcrum at the connection point where the first joint part and the second joint part connect to the frame, the point where the first joint part connects to the exciter film, and the second joint part becomes the diaphragm. It functions as a lever where the point connected to is the point of action. Thereby, the expansion and contraction of the exciter film can be effectively propagated to the diaphragm.

  The planar speaker of the present invention preferably has the following configuration. The length of connecting the end of the exciter film and the end of the frame by the first joint is shorter than the length of connecting the end of the diaphragm and the end of the frame by the second joint.

  In this configuration, due to the lever principle, the expansion and contraction of the diaphragm is larger than the expansion and contraction of the exciter film. Thereby, the expansion and contraction of the exciter film can be more effectively propagated to the diaphragm.

  Moreover, the piezoelectric film of the planar speaker of the present invention may be an organic piezoelectric material.

  In this configuration, the piezoelectric film is formed of polyvinylidene fluoride (PVDF), polylactic acid (PLLA), or the like.

  In the planar speaker of the present invention, at least a part of the diaphragm may be made of an elastic film.

  In this configuration, the stress generated when the diaphragm is fixed to the exciter film via the connecting portion is relieved, and the main surface of the diaphragm can be made flat without being curved.

  Moreover, it is preferable that the diaphragm of the planar speaker of the present invention is made of a material having translucency.

  In this configuration, since the diaphragm has translucency, what is arranged on the back side (exciter film side) of the diaphragm can be viewed from the front side of the diaphragm.

  The present invention also relates to an AV device, and includes a flat speaker having the above-described translucent diaphragm, and the frame includes a thin display unit having the diaphragm side as a display surface.

  In this configuration, since the thin display unit is arranged in the flat speaker, a thin AV device can be realized.

  According to the present invention, it is possible to realize a thin flat speaker having an excellent sound quality characteristic and having a size substantially equal to the area of the vibration surface.

It is the front view and side view of the planar speaker which concern on the 1st Embodiment of this invention. It is a partial expanded side view of the planar speaker which concerns on the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the planar speaker which concerns on the 1st Embodiment of this invention. It is operation | movement explanatory drawing of the planar speaker which concerns on the 2nd Embodiment of this invention. It is the front view and side view of the planar speaker which concern on the 3rd Embodiment of this invention. It is the front view and side view of the planar speaker which concern on the 4th Embodiment of this invention. It is a partial expanded side view of the planar speaker which concerns on the 5th Embodiment of this invention. It is a partial expanded side view of the planar speaker which concerns on the 6th Embodiment of this invention.

  A planar speaker according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a front view of a flat speaker according to the first embodiment of the present invention, and FIG. 1B is a side view of the flat speaker. FIG. 2 is a partially enlarged view of the flat speaker according to the first embodiment of the present invention.

The flat speaker 10 includes a piezoelectric film 20, an exciter film 30, a diaphragm 40, and a connecting member 50.

  The piezoelectric film 20 includes a base film 200 having a rectangular shape in plan view. Electrodes 201 are formed on both opposing main surfaces of the base film 200. The base film 200 is a film having piezoelectricity, and is preferably made of polylactic acid (hereinafter referred to as PLA) or polyvinylidene fluoride (hereinafter referred to as PVDF). More preferably, it is composed of PLA. By comprising PLA, the translucency of the base film 200 can be made very high. If the usage is such that there is no problem even if the translucency is low, a laminate in which a PVDF film having a thinner thickness is laminated, or a laminate in which a PLA film having a thinner thickness is laminated can be used. Thereby, the apparent piezoelectric constant of the piezoelectric film can be improved and the driving voltage of the piezoelectric film can be lowered. When PLA is used for the base film 200, the base film 200 is preferably formed in a rectangular shape by cutting so that each outer periphery is approximately 45 ° with respect to the stretching direction.

  The electrode 201 is formed on substantially the entire main surfaces of the base film 200. The electrode 201 is preferably composed mainly of indium tin oxide ITO, zinc oxide ZnO, and polythiophene. Since these materials are highly translucent, by combining with a base film 200 made of PLA, a piezoelectric film 20L that is substantially transparent (visible light transmissivity is about 95%) or more is realized. Can do. Note that a silver nanowire electrode can be used as the electrode 201, and an aluminum vapor-deposited electrode is preferably used as long as there is no problem even if the translucency is low. A lead wiring conductor (not shown) is connected to the electrode 201, and a sound emission drive signal from the outside is applied to each electrode 201 through the wiring conductor.

  The exciter film 30 has a rectangular shape in plan view, and is formed in a size that allows the piezoelectric film 20 to be disposed. The exciter film 30 is made of polyethylene terephthalate (PET). The exciter film 30 may use other materials such as polyethylene nanophthalate (PEN), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), and functionally the shape of the diaphragm 40. As long as it has a strength that can sufficiently maintain the above. Furthermore, the exciter film 30 is better if it is an insulating material having high translucency.

  For example, when PLA is used for the base film 200 of the piezoelectric film 20 and PET is used for the exciter film 30, the thickness of the exciter film 30 is preferably about 0.05 mm to 0.2 mm.

  A piezoelectric film 20 is disposed on one main surface of the exciter film 30. The piezoelectric film 20 is fixed to the exciter film 30 using an adhesive layer 23. At this time, the piezoelectric film 20 is fixed so that the stretching direction forms an angle of about 45 ° with respect to each outer periphery of the exciter film 30.

  The diaphragm 40 has a rectangular shape in plan view. The diaphragm 40 is made of a material having a predetermined rigidity and is made of acrylic resin (PMMA). The diaphragm 40 may be made of other materials such as PET, polycarbonate (PC), PLA, etc., and may be any insulating material having a high translucency functionally.

  The diaphragm 40 is arranged on the one main surface side (piezoelectric film 20 side) of the exciter film 30 with a predetermined interval. At this time, the main surface of the diaphragm 40 and the main surface of the exciter film 30 are substantially parallel.

  The length in the first direction (the length in the horizontal direction in FIG. 1) constituting the main surface of the diaphragm 40 is substantially the same as that of the exciter film 30. The length in the second direction (length in the vertical direction in FIG. 1) constituting the main surface of the diaphragm 40 orthogonal to the first direction is longer than that of the exciter film 30.

  The frame 300 has a rectangular shape in plan view. The frame 300 is made of a material having higher rigidity than the diaphragm 40. The frame 300 may be an insulating material having high translucency. Further, the frame 300 may have a shape in which the center of the main surface is opened, that is, a shape having a flesh portion with a predetermined width on the outer peripheral portion.

  The frame 300 is disposed between the exciter film 30 and the diaphragm 4 with a space therebetween. At this time, the main surface of the frame 300 and the main surface of the exciter film 30 are parallel to each other.

  The length in the first direction constituting the main surface of the frame 300 (the length in the horizontal direction in FIG. 1) is substantially the same as that of the exciter film 30 and the diaphragm 40. The length in the second direction (length in the vertical direction in FIG. 1) constituting the main surface of the frame 300 orthogonal to the first direction is shorter than that of the exciter film 30.

  The exciter film 30, the frame 300, and the diaphragm 40 are connected by a connecting member 50. The connecting member 50 is disposed on a side (second direction end side) forming the end portion in the second direction of the exciter film 30, the frame 300, and the diaphragm 40. The connecting member 50 is also made of a highly rigid material.

  The connecting member 50 is formed by integrally forming a first joint portion 501 and a second joint portion 502. The first joint portion 501 and the second joint portion 502 are made of a long plate. The first joint portion 501 and the second joint portion 502 are connected across the entire sides along the longitudinal direction. At this time, the first joint portion 501 and the second joint portion 502 are connected in a shape in which the short direction perpendicular to the long direction of the flat plate is substantially orthogonal. Thereby, the connecting member 50 is L-shaped when viewed from the direction parallel to the longitudinal direction of the first joint portion 501 and the second joint portion 502.

  The corner side where the first joint portion 501 and the second joint portion 502 of the connecting member 50 are connected is connected to the second direction end side of the frame 300. At this time, the first joint portion 501 and the second joint portion 502 of the connecting member 50 are pivotally connected to the frame 300 when viewed from a direction parallel to the longitudinal direction.

  An end side opposite to the corner side of the first joint portion 501 of the connecting member 50 is connected to an end side in the second direction of the exciter film 30. At this time, the first joint portion 501 is rotatably connected to the exciter film 30 when viewed from a direction parallel to the longitudinal direction.

  The end of the connecting member 50 opposite to the corner of the second joint portion 502 is connected to the end of the diaphragm 40 in the second direction. At this time, the second joint portion 502 is rotatably connected to the diaphragm 40 when viewed from a direction parallel to the longitudinal direction.

  As described above, the exciter film 30, the diaphragm 40, and the frame 300 are attached to the connecting member 50 so that the exciter film 30, the diaphragm 40, and the frame 300 can be rotated with respect to the connecting member 50. If so, the specific structure may be any structure.

  With such a configuration, the connection portion between the coupling member 50 and the frame 300 becomes a fulcrum 511 for propagating the expansion and contraction of the exciter film 30 to the diaphragm 40. A connecting portion between the first joint portion 501 and the exciter film 30 serves as a power point 512 for propagating the expansion and contraction of the exciter film 30 to the diaphragm 40. A connecting portion between the second joint portion 502 and the diaphragm 40 serves as an action point 513 for propagating the expansion / contraction of the exciter film 30 to the diaphragm.

  FIG. 3 is a diagram for explaining the operation of the flat speaker according to the first embodiment of the present invention. 3, the side view in the steady state of the piezoelectric film 20, the expansion | extension state of the piezoelectric film 20, and the contraction state of the piezoelectric film 20 is shown.

  First, in a steady state, the diaphragm 40 is fixed to the exciter film 30 by the frame 300 and the connecting member 50. At this time, the exciter film 30 and the diaphragm 40 are fixed so that bending stress is applied. In other words, the exciter film 30 and the diaphragm 40 are fixed so that tensile stress is applied to the exciter film 30 along the second direction. More specifically, the diaphragm 40 is fixed so as to be curved and protrude toward the side opposite to the side where the exciter film 30 exists (front side of the front face of the diaphragm 40). 1 and 3 exaggerately describe the curved state of the diaphragm 40. Actually, as shown in FIG. 2, the main surface of the diaphragm 40 and the main surface of the exciter film 30 are The relationship becomes more parallel.

  In such a state, when the sound emission drive signal is applied to the piezoelectric film 20 and the piezoelectric film 20 is stretched along the second direction, the exciter film 30 is shown in S901 as shown in the stretched state of FIG. Elongate. When the exciter film 30 expands as shown in S901, the first joint portion 501 of the connecting member 50 rotates toward the diaphragm 40 side with the connecting portion between the connecting member 50 and the frame 300 as a fulcrum. By the rotation of the first joint portion 501, the second joint portion 502 connected to the first joint portion 501 also rotates toward the diaphragm 40 with the connection portion between the coupling member 50 and the frame 300 as a fulcrum.

  The connecting members 50 are arranged at both ends in the second direction, and the distance between the both ends in the second direction of the diaphragm 40 by rotating the respective second joint portions 502 toward the diaphragm 40 side. Becomes shorter. Thereby, the protrusion amount with respect to the front front side increases at the diaphragm 40.

  When the sound emission drive signal is applied to the piezoelectric film 20 and the piezoelectric film 20 contracts along the second direction, the exciter film 30 contracts as shown in S902 as shown in the contracted state of FIG. . When the exciter film 30 contracts as shown in S902, the first joint portion 501 of the connecting member 50 rotates toward the exciter film 30 with the connecting portion between the connecting member 50 and the frame 300 as a fulcrum. By the rotation of the first joint portion 501, the second joint portion 502 connected to the first joint portion 501 also rotates toward the diaphragm 40 with the connection portion between the coupling member 50 and the frame 300 as a fulcrum.

  The connecting members 50 are disposed at both ends in the second direction, and the distance between both ends in the second direction of the diaphragm 40 is as each second joint portion 502 rotates toward the exciter film 30 side. Becomes longer. Thereby, the projection amount with respect to the front front side of the diaphragm 40 is reduced.

  As described above, when the sound emission drive signal is applied to the piezoelectric film 20 by using the configuration of the present embodiment, the vibration plate 40 is vibrated according to the sound emission drive signal and emitted to the front. be able to.

  Then, as described above, a constant bending stress is applied to the diaphragm 40, and stress due to expansion / contraction of the exciter film 40 in the same direction as the bending stress (expansion / contraction that propagates expansion / contraction of the piezoelectric film 20) is applied. Thus, the diaphragm 40 can be vibrated effectively. Furthermore, since the piezoelectric film 20 can be disposed on substantially the entire surface of the planar speaker 10 in plan view, the bass output characteristics can be improved, and the diaphragm 40 can be vibrated most efficiently in the determined area. Further, since an electromagnetic exciter as shown in the conventional Patent Document 2 is not required, the flat speaker 10 can be formed in a small size (small area when viewed from the front). Further, as viewed from the side, the exciter film 30 and the diaphragm 40 to which the piezoelectric film 20 is attached have a slight margin with respect to the distance corresponding to the vibration stroke of the diaphragm 40 and the moving amount of the frame 300. Since it suffices to arrange them apart from each other, the length in the depth direction as shown in the conventional patent document 3 is hardly required, and the flat speaker 10 can be formed thin.

  In addition, although sound is emitted also to the exciter film 30 side of the diaphragm 40, the exciter film 30 side of the diaphragm 40 functions as an enclosure of a semi-closed space by the above-mentioned structure. Thereby, it can suppress that the sound emitted to the exciter film 30 side leaks to the front side, and can improve a sound quality characteristic.

  In the above description, the length of the first joint part 501 (the distance between the connection position of the first joint part 501 to the frame 300 and the connection position of the first joint part 501 to the exciter film 30), The relationship between the length of the second joint portion 502 (the distance between the connection position of the second joint portion 502 to the frame 300 and the connection position of the second joint portion 502 to the diaphragm 40) was not particularly shown. The two joint portions 502 may be made longer than the length of the first joint portion 501. Thereby, from the lever principle, the amount of change between the edges in the second direction of the diaphragm 40 becomes larger than the amount of expansion / contraction of the exciter film 30. Therefore, the expansion and contraction of the exciter film 30 can be amplified and the diaphragm 40 can be vibrated. Thereby, sound can be emitted more effectively.

  Next, a planar speaker according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a diagram for explaining the operation of the flat speaker according to the second embodiment of the present invention. FIG. 4 shows a side view of the piezoelectric film 20A in a steady state, the piezoelectric film 20A in an expanded state, and a piezoelectric film 20A in a contracted state.

  The planar speaker 10A according to the present embodiment is different from the diaphragm 40 of the first embodiment in the material of the diaphragm 40A, and other configurations are the same as those of the planar speaker 10 according to the first embodiment. It is.

  The diaphragm 40A has the same shape as the diaphragm 40 shown in the first embodiment, and is made of a different material. The material of the diaphragm 40A is a stretchable material such as polyurethane. By setting it as such a structure, as shown in FIG. 4, it can suppress that the diaphragm 40 curves in a steady state. Moreover, as shown in FIG. 4, even if the exciter film 30 expands and contracts, the diaphragm 40 does not curve.

  Thereby, the main surface of the diaphragm 40A can be flattened, and the front surface of the flat speaker 10A can be flattened.

  Next, a planar speaker according to a third embodiment of the present invention will be described with reference to the drawings. FIG. 5A is a front view of a flat speaker according to the third embodiment of the present invention, and FIG. 5B is a side view of the flat speaker.

  The planar speaker 10B according to the present embodiment is different from the diaphragm 40 of the first embodiment in the structure of the diaphragm 40B, and the other configurations are the same as those of the planar speaker 10 according to the first embodiment. It is.

  The diaphragm 40 </ b> B includes a main plate 401 and a frame plate 402. The main plate 401 is made of a material having a predetermined rigidity, like the diaphragm 40 shown in the first embodiment. The length of the main plate 401 in the first direction is the same as that of the exciter film 30. The length of the main plate 402 in the second direction is shorter than that of the exciter film 30. The frame plate 402 is made of a stretchable material, like the diaphragm 40A shown in the second embodiment. The length of the frame plate 402 in the first direction is the same as that of the exciter film 30. The length of the frame plate 402 in the second direction is shorter than that of the exciter film 30.

  The frame plates 402 are disposed at both ends of the main plate 401 in the second direction. The frame plate 402 is bonded to the main plate 401 with an adhesive or the like, and is connected to the second joint portion 502 of the connecting member 50.

  Even with such a structure, the main surface of the diaphragm 40B can be flattened and the front surface of the flat speaker 10B can be flattened, as in the second embodiment.

  Next, a planar speaker according to a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 6A is a front view of a flat speaker according to the fourth embodiment of the present invention, and FIG. 6B is a side view of the flat speaker.

  The planar speaker 10C of the present embodiment is different from the planar speaker 10 of the first embodiment in the shape of the piezoelectric film 20C, and other configurations are the same as those of the planar speaker 10 of the first embodiment. .

  The area of the piezoelectric film 20 </ b> C viewed from the front is smaller than that of the exciter film 30. The piezoelectric film 20 </ b> C is disposed substantially at the center of the exciter film 30 when viewed from the front.

  If the sound quality characteristics required by the flat speaker 10C are obtained, the piezoelectric film 20C can be made small. As a result, the planar speaker can be configured at a lower cost while obtaining the required sound quality characteristics.

  Next, a planar speaker according to a fifth embodiment of the present invention is described with reference to the drawings. FIG. 7 is a partially enlarged side view of a flat speaker according to a fifth embodiment of the present invention.

  The planar speaker 10D of the present embodiment is different from the planar speaker of the first embodiment in the shape of the connecting member 500D, the mounting structure of the exciter film 30D, the diaphragm 40D, and the frame 300 with respect to the connecting member 500D. The configuration of is the same.

  The connecting member 500D has the same basic structure as the connecting member 50 shown in the first embodiment, and includes a first joint portion 501D and a second joint portion 502D. The first joint portion 501D and the second joint portion 502D are connected so as to be L-shaped when viewed in a direction parallel to the main surfaces of the exciter film 30D, the diaphragm 40D, and the frame 300.

  A corner side of the coupling member 500D where the first joint portion 501D and the second joint portion 502D are connected is in contact with the side on the diaphragm 40D side of the end surface in the second direction of the frame 300. In this state, the connecting member 500D and the frame 300 are fixed by the flexible resin film 520D. At this time, the flexible resin film 520D is attached to the surface on the diaphragm 40D side of the frame 300 and the surface on the diaphragm 40D side of the second joint portion 502D of the connecting member 500D. With such a structure, the contact position between the corner side of the connecting member 500D and the side on the diaphragm 40D side of the end surface in the second direction of the frame 300 becomes the fulcrum 511D, and the flexible resin film 520D functions as a hinge. To do.

  A bent portion 31D that is bent toward the frame 300 is formed at the end in the second direction of the exciter film 30D. The bent portion 31D is bonded to the surface of the first joint portion 501D on the second joint portion 502D side. The bonding position between the exciter film 30D and the first joint portion 501D is a force point 512D.

  A bent portion 41D that is bent toward the frame 300 is formed at the end in the second direction of the diaphragm 40D. The bent portion 41D is bonded to the surface of the second joint portion 502D on the first joint portion 501D side. A bonding position between the diaphragm 40D and the second joint portion 501D is a force point 513D.

  Even with such a structure, it is possible to realize a flat type speaker that is thin and excellent in sound quality characteristics, as in the above-described embodiments. Furthermore, by using the configuration of this embodiment, a mechanism for propagating the expansion and contraction of the exciter film 30D to the diaphragm 40D can be realized with a relatively simple structure, and a flat speaker can be easily manufactured. .

  Next, a planar speaker according to a sixth embodiment of the present invention will be described with reference to the drawings. FIG. 8 is a partially enlarged side view of a flat speaker according to a sixth embodiment of the present invention.

  The planar speaker 10E of the present embodiment is different from the planar speaker of the first embodiment in the shape of the connecting member 500E, the mounting structure of the exciter film 30E, the diaphragm 40E, and the frame 300 with respect to the connecting member 500E. The configuration of is the same.

  The connecting member 500E is a long prism. The first corner side of the connecting member 500 </ b> E is in contact with the side on the diaphragm 40 </ b> E side of the end surface in the second direction of the frame 300. In this state, the connecting member 500E and the frame 300 are fixed by the flexible resin film 520E. At this time, the flexible resin film 520E is attached to the surface on the diaphragm 40E side of the frame 300 and the surface on the diaphragm 40E side of the connecting member 500E. With such a structure, the contact position between the first corner side of the connecting member 500E and the side on the diaphragm 40E side of the second direction end surface of the frame 300 becomes the fulcrum 511E, and the flexible resin film 520E Functions as a hinge.

  A bent portion 31E that is bent toward the frame 300 is formed at an end portion in the second direction of the exciter film 30E. The bent portion 31E is bonded to the surface of the connecting member 500E opposite to the surface on which the flexible resin film 511E is mounted. The bonding position between the exciter film 30E and the connecting member 500E is a force point 512E.

  A bent portion 41E that is bent toward the frame 300 is formed at the second direction end of the diaphragm 40E. The bent portion 41E is bonded to the surface opposite to the frame 300 perpendicular to the surface on which the flexible resin film 511E of the connecting member 500E is mounted. The bonding position between the diaphragm 40E and the connecting member 500E is an action point 512E.

  Even with such a structure, it is possible to realize a flat type speaker that is thin and excellent in sound quality characteristics, as in the above-described embodiments. Furthermore, by using the configuration of this embodiment, a mechanism for propagating the expansion and contraction of the exciter film 30D to the diaphragm 40D can be realized with a simpler structure, and a flat speaker can be manufactured more easily. .

  In each of the embodiments described above, an example in which the frame 300 is used has been described. However, the frame 300 may be replaced with a thin display unit having a rectangular shape when viewed from the front. For example, a liquid crystal display device may be used as the thin display unit. The thin display unit is arranged so that the display surface is on the diaphragm side. The diaphragm is a light-transmitting material.

  With such a configuration, it is possible to realize an AV device that displays not only audio but also video and images while maintaining the external shape as a flat speaker. That is, a thin AV device can be realized.

10, 10A, 10B, 10C, 10D, 10E: planar speakers,
20: Piezoelectric film,
23: adhesive layer,
30, 30D, 30E: Exciter film,
31D, 31E: bent part,
40, 40A, 40B, 40D, 40E: diaphragm,
41D, 41E: bent portion,
50,500D, 500E: connecting member,
200: Base film,
201: electrode,
300: Frame,
401: main plate,
402: Frame plate,
501, 501 D: first joint part,
502, 502D: second joint portion,
511, 511D: fulcrum,
512, 512D: Power point,
513,513D: point of action,
520D, 520E: flexible resin film,

Claims (7)

A piezoelectric film made of a piezoelectric resin having electrodes formed on both main surfaces;
A flat exciter film having the piezoelectric film mounted on at least one main surface;
A flat diaphragm arranged at a predetermined interval in a direction orthogonal to the main surface of the exciter film;
A frame that is formed in a smaller area than the main surface of the exciter film and the diaphragm, and is disposed between the exciter film and the diaphragm;
An end portion of the exciter film, an end portion of the frame, and an end portion of the diaphragm, and a connecting portion that propagates expansion and contraction of the exciter film to the diaphragm using the end portion of the frame as a fulcrum. The
Flat speaker. The connecting portion is
A first joint for connecting an end of the exciter film and an end of the frame;
A second joint for connecting the end of the frame and the end of the diaphragm,
The first joint part and the second joint part are connected at a substantially right angle,
The planar speaker according to claim 1. The length connecting the end portion of the exciter film and the end portion of the frame by the first joint portion is:
The planar speaker according to claim 2, wherein the planar speaker is shorter than a length connecting the end of the diaphragm and the end of the frame by the second joint portion.   The flat speaker according to any one of claims 1 to 3, wherein the piezoelectric film is made of an organic piezoelectric material.   The flat speaker according to any one of claims 1 to 4, wherein at least a part of the diaphragm is made of a stretchable film.   The planar speaker according to claim 1, wherein the diaphragm is made of a light-transmitting material. A flat speaker according to claim 6,
The frame is an AV device including a thin display unit having the diaphragm side as a display surface.

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