Patent Publication Number: US-8126189-B2

Title: Multi-directional flat speaker device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial no. 98104651, filed on Feb. 13, 2009. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The disclosure relates to a speaker device. More particularly, relates to a multi-directional flat speaker device. 
     2. Background 
     The two most direct sensory systems of human being are visual and audible systems, so for a long time, scientists try their best to develop related elements or system techniques. The demand of providing the user with more plentiful or specific sound fields by utilizing the composition of speaker system will be consistent in the future market application. Recently, electro-acoustic speakers are mainly classified into direct and indirect radiating types, and are approximately classified into moving coil, piezoelectric, and electrostatic speakers according to driving manners. The moving coil speaker is currently the most commonly used and most mature product. However, a moving coil speaker cannot be compressed due to the physical structure thereof. Accordingly, moving coil speaker is not suitable for 3C products and home entertainment systems which have their sizes reduced constantly. A piezoelectric speaker pushes a membrane to produce sounds based on the piezoelectric effect of an electrical material (i.e., the material is deformed when an electric field is supplied thereon). Although having a compressed and small structure, the piezoelectric speaker can not be flexible as the electrical material requires sintering. 
     Currently, the manufacture of speakers still applies the design production method as that for a single unit as illustrated in U.S. Pat. No. 3,894,199. 
     As for the electrostatic speaker, for example, in U.S. Pat. No. 3,894,199, an electro-acoustic transducer structure is mainly provided, as shown in  FIG. 1 . The structure includes two fixed electrode structures  110  and  120  placed on two sides. The fixed electrode structures  110  and  120  have a plurality of pores for scattering the sounds generated. A vibrating film  130  is disposed between the fixed electrode structures  110  and  120 . A fixing structure  140  is made of an insulation material, and used to fix the fixed electrode structures  110  and  120  and the vibrating film  130 . The fixed electrode structures  110  and  120  are respectively connected to an AC source  160  through a transformer  150 . When an AC signal is transmitted to the fixed electrode structures  110  and  120 , a potential is alternately changed to enable the vibrating film  130  to generate vibration due to difference potentials on two sides thereof, and thereby generating corresponding sound. However, the above configuration needs to enhance the sound-pressure output, so an additional power element is required to work together with the driving process. In this manner, the apparatus not only has a large volume, but more elements are used, and the cost is also relatively high. In addition, the fixing structure  140  must fix the fixed electrode structures  110  and  120  and the vibrating film  130 , so the electro-acoustic transducer structure cannot achieve the flexible characteristics. 
     SUMMARY 
     The embodiment is a multi-directional flat speaker device, which includes a plurality of speakers having directional effects, a control mechanism, and a serial connection device. The speakers with directional effects can transmit sounds to appointed locations. The control mechanism is directed to control the rotation angles of the speakers having directional effects. The serial connection device is directed to connect the speakers having directional effects. 
     In one embodiment, the multi-directional flat speaker device includes a plurality of flat speakers with sound field directional characteristics, a serial connection mechanism, and a control mechanism. The serial connection mechanism is configured to connect the flat speakers serially in a parallel manner. The control mechanism controls one or more of the flat speakers to rotate respectively, and generates a directional sound field according to the rotation angle of the flat speaker. 
     In the multi-directional flat speaker device, wherein the control mechanism independently actuates each of the flat speakers to rotate a corresponding angle thereof, or actuates all of the flat speakers to rotate a same angle. 
     In the multi-directional flat speaker device, wherein the control mechanism drives the serial connection mechanism to rotate through a transmission belt. The control mechanism can apply the mechanical or electrical controlling manner. 
     The multi-directional flat speaker device, wherein the flat speakers are connected to an audio input interface for receiving at least one or a plurality of set(s) of audio signal inputs, and transmitting the foregoing audio signals to the corresponding flat speakers. 
     In the multi-directional flat speaker device, wherein the audio input interface receives a plurality of processed divided signals and transmits the processed divided signals to each of the appointed speakers with directional effects through the serial connection mechanism. Afterward, the control mechanism is utilized in cooperation to drive each of the flat speakers for transmitting the processed divided signals, which is obtained from the audio input interface, to a specific direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the embodiment, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and, together with the description, serve to explain the principles of the embodiment. 
         FIG. 1  illustrates an electro-acoustic transducer structure. 
         FIG. 2A  is a schematic structural diagram of a multi-directional flat speaker device according to an embodiment of the embodiment. 
         FIG. 2B  is a schematic structural diagram of a control mechanism of the multi-directional flat speaker device in  FIG. 2A . 
         FIG. 2C  is a schematic diagram of a method of driving a stepping motor of the multi-directional flat speaker device in  FIG. 2A . 
         FIG. 3  is a schematic structural diagram of a flat speaker with characteristics of being flexible and the like according to another embodiment of a multi-directional flat speaker device in the embodiment. 
         FIG. 4  is a schematic structural diagram of a multi-directional flat speaker device having baffle structures according to another embodiment. 
         FIG. 5A  is a schematic diagram of a multi-directional flat speaker device capable of adjusting angles individually according to another embodiment. 
         FIG. 5B  is an enlarged diagram showing a part of  FIG. 5A . 
         FIG. 6A  is a schematic diagram of a multi-directional flat speaker device capable of adjusting angles individually and having baffle structures according to another embodiment. 
         FIG. 6B  is a schematic diagram of a different disposition design according to another embodiment. 
         FIG. 7A  and  FIG. 7B  are schematic diagrams of supporting structures of a flat speaker in a multi-directional flat speaker device provided in the embodiment. 
         FIG. 8  is a schematic diagram of the assembly and disassembly of a flat speaker in a multi-directional flat speaker device provided in the embodiment. 
         FIG. 9  is a schematic structural diagram of a flat speaker unit applied in a multi-directional flat speaker device provided in the embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The electrostatic speaker includes mainly Hi-End earphone and loudspeaker in the current market. The operating principle for the conventional electrostatic speaker is that two fixed electrode plates with holes are used to clamp a conductive vibrating film to form a capacitor, and then a DC bias is applied to the vibrating film and an AC voltage is applied to two fixed electrodes, and electrostatic force generated by the positive and negative electric fields is used to drive the conductive vibrating film to vibrate and to radiate sounds. The basic structure of the thin-type flat speaker technology has a characteristic of being high directional, and this characteristic can be applied in the design of sound fields. 
     In one embodiment provides that by the sound field directional characteristics of the flat speaker device, accompanied with the external multi-directional control mechanism, a composite sound field is generated as desired accordingly. The design makes the applications of the flat speaker device more suitable to meet the requirement of future utilizations. 
     The multi-directional control mechanism to actuate the flat speakers can be achieved by controlling one or more of the flat speakers to rotate in a unique manner or independently. The control mechanism can be designed by a mechanical or an electrical controlling manner. 
     Therefore, in the application of conventional speakers, the flat speakers with directivity can be utilized so as to be apart from the design of conventional speakers. Consequently, the sound components can be utilized in many other application fields, and is becoming a major point in the development of flat speaker techniques. 
     The multi-directional flat speaker device includes a plurality of speakers having directional effects, a control mechanism, and a serial connection device. The speakers with directional effects can transmit sounds to preset locations. The control mechanism, such as a control unit, is directed to control the rotation angles of the speakers having directional effects. The serial connection device is directed to connect the speakers having directional effects. The audio input interface is configured to receive the external audio signal inputs. 
     In the multi-directional flat speaker device, wherein the control mechanism can control the speakers with directional effects to make sounds at the same direction or individual directions. 
     In the multi-directional flat speaker device, wherein the serial connection device can be assembled by transmission lines that are sharing transmission audio signals or by applying an external facilitating connection mechanism. 
     In the multi-directional flat speaker device, wherein the audio input interface can receive one or a plurality of set(s) of audio signals. If the sets of audio signals are inputted, the audio signals can be a plurality of identical signals or a plurality of processed divided signals. 
     In the multi-directional flat speaker device, if the audio input interface receives the processed divided signals, the signals can be transmitted to each of the preset speakers with directional effects through the serial connection device. Afterward, the control mechanism is utilized in cooperation to drive each of the speakers with directional effects for transmitting the processed divided signals, which is obtained from the audio input interface, to a specific direction. 
     In the multi-directional flat speaker device of the embodiment, the effect of special sound field is achieved by utilizing the directional characteristics of the flat electrostatic speaker structure. The fundamental principle of the flat electrostatic speaker utilizes the charge characteristics and the electrostatic force effect in the vibrating film material. When the vibrating film is stimulated by an external voltage, the vibrating film surface generates deformation, so as to drive the air around the vibrating film to generate sounds. As known from the electrostatic force formula and energy laws that, the force applied on the vibrating film equals to the capacitance value of the whole speaker multiplied by the intensity of the internal electric field and the externally-inputted sound voltage signal, and the larger the force applied on the vibrating film is, the louder the outputted sound is. 
     On the other hand, the moving coil speakers can not apply multiple sets of moving coil speakers within a suitable area for achieving the sound directional effect. Hence, the embodiment provides diagrams as illustrated in  FIGS. 2A˜2C , which the speakers are assembled with a structure similar to that of the shutters. As illustrated in  FIG. 2A , a multi-directional flat speaker device includes a plurality of flat speakers with directional effects  210 ,  211 ,  212 ,  213 ,  214 , and  215 , and the surfaces thereof include a plurality of sound holes. A serial connection mechanism, for example, a plurality of serial connection devices  220 ,  221 ,  222 ,  223 ,  224 , and  225  as illustrated in the diagrams, is configured to serially connect the flat speakers  210 ,  211 ,  212 ,  213 ,  214 , and  215  in a parallel manner, so as to drive the serially connected flat speakers to rotate in a direction  240  or an opposite direction  242 . A control mechanism  230  is configured for driving the serial connection devices  220 ,  221 ,  222 ,  223 ,  224 , and  225  to rotate. Moreover, an audio input interface  250  can receive one or a plurality of set(s) of audio signals from an external music playing device, and then transmit the audio signals to the flat speakers  210 ,  211 ,  212 ,  213 ,  214 , and  215 . 
     The serial connection mechanism is driven by a control mechanism, and is configured to actuate the flat speakers to individually rotate in the same direction or different directions. The control mechanism can be achieved by a method of assembling an electrical circuit and a mechanical mechanism. In one embodiment, a method of assembling a simple mechanical mechanism, for example, applying a structure similar to the structures of shutters that are pulled manually, can be used. In addition, a method of linking serial connected thin-type flat speakers is to apply transmission lines for transmitting audio signals or an external facilitating mechanism. 
     Referring to  FIG. 2B , a schematic diagram of the control mechanism in one embodiment is illustrated. The control mechanism  230  includes a stepping motor  232 , a driving circuit  234 , a controller  236 , and a power managing unit  238 . The stepping motor  232  is configured for driving the serial connection devices  220 ,  221 ,  222 ,  223 ,  224 , and  225  to rotate. The driving circuit  234  is configured to generate a control signal for driving. Moreover, the controller  236  is configured to calculate and control a rotation angle. The power managing unit  238  provides a power to drive the driving device  230 . The driving device  230  drives the serial connection device so that multiple embodiments for rotating the flat speakers are available. In one embodiment, a driving method of the stepping motor  232  can be as illustrated in  FIG. 2C , where the serial connection devices  220 ,  221 ,  222 ,  223 ,  224 , and  225  have gear wheels on two sides, and are rotated via a transmission belt  231 . The transmission belt  231  is connected to the stepping motor  232  to drive the transmission belt  231  to move up and down, and thereby driving the gear wheels on the two sides of the serial connection devices to rotate. 
     By controlling the thin-type flat speakers  210 ,  211 ,  212 ,  213 ,  214 , and  215  that are serially connected, the control mechanism  230  can control the serially connected thin-type flat speakers to send sounds in a same direction by using the directional characteristics thereof. Hence, the sound sending location can receive a volume louder than the normal. 
     In a multi-directional flat speaker device  200 , the flat speakers  210 ,  211 ,  212 ,  213 ,  214 , and  215  are connected to an audio input interface  250  for receiving one or a plurality set(s) of audio signals from an external music playing device. If the sets of audio signals are inputted, then the signals can be a plurality of identical signals or a plurality of processed divided signals. 
     In the multi-directional flat speaker device  200 , if the audio input interface receives the processed divided signals, the signals can be transmitted to each of preset speakers with directional effects through the serial connection mechanism. Afterward, the control mechanism is utilized in cooperation to drive each of the speakers with the directional effects for transmitting the processed divided signals of the audio input interface to a specific direction. 
     In another embodiment of the multi-directional flat speaker device, a flat speaker with characteristics of being light, thin, flexible, and the like can be applied as illustrated in  FIG. 3 . In a multi-directional flat speaker device  300 , a flexible flat speaker  310  can roll up a serial connection device  320 . Next, the flexible flat speaker  310  can be rolled out and then adjusts a direction for sending sounds through supporting elements on two ends of the serial connection device  320 . 
     Referring to  FIG. 4 , according to an embodiment of the multi-directional flat speaker device in the embodiment, a multi-directional flat speaker device  400  includes a plurality of flat speakers with directional effects  410 ,  411 ,  412 , and  413  as shown in the diagram, for example, where surfaces thereof includes a plurality of sound holes. A plurality of serial connection devices  420 ,  421 ,  422 , and  423  is serially connected to a plurality of corresponding flat speakers  410 ,  411 ,  412 , and  413  respectively so as to drive the serially connected flat speakers to rotate in a direction  440  or a direction  442 . In order to enhance the directional effects of the flat speakers, increase reflectivity of sounds, or prevent interferences between adjacent speakers, the multi-directional speaker device  400  is joined with baffles  450  and  454  for increasing the sound reflectivity or preventing the interferences between adjacent speakers. The baffles  450  and  454  respectively include serial connection devices  452  and  456  for control mechanisms to control rotations thereof. 
     In another embodiment of the multi-directional flat speaker device, a control mechanism can be utilized to control serially connected thin-type flat speakers for sending sounds individually to directions preset by a user. Therefore, audience at different locations can all sense the audio information as required. Referring to  FIG. 5A , a multi-directional flat speaker device  500  includes a plurality of flat speakers with directional effects  510 ,  511 ,  512 ,  513 ,  514 , and  515 , and surfaces thereof include a plurality of sound holes. A plurality of serial connection devices  520 ,  521 ,  522 ,  523 ,  524 , and  525  is serially connected to the corresponding flat speakers  510 ,  511 ,  512 ,  513 ,  514 , and  515  respectively. A control mechanism  530  is configured for driving the serial connection devices  520 ,  521 ,  522 ,  523 ,  524 , and  525  to rotate. Moreover, an audio input interface  550  can receive one or a plurality of set(s) of audio signals from an external music playing device. The audio input interface  550  then transmits the audio signals to the flat speakers  510 ,  511 ,  512 ,  513 ,  514 , and  515 . 
     The serial connection devices  520 ,  521 ,  522 ,  523 ,  524 , and  525  are respectively driven by the control mechanism, so that every flat speaker can rotate at a different angle. In other words, sounds can be sent to the directions preset by the user as illustrated in  FIG. 5A . Here, the flat speaker  510  rotates an angle  541 , the flat speaker  511  rotates an angle  542 , the flat speaker  514  rotates an angle  543 , and the flat speaker  515  rotates an angle  544 . 
     In order to achieve this goal, in one embodiment, a control mechanism  530  and a plurality of stepping motors  532  are respectively connected to the serial connection devices  520 ,  521 ,  522 ,  523 ,  524 , and  525 . Each of the serial connection devices  520 ,  521 ,  522 ,  523 ,  524 , and  525  has, for example, gear wheels on two sides. Moreover, every gear wheel is engaged to a stepping motor  532  correspondingly, and driven by the stepping motor  532  to rotate. The driving circuit and the control mechanism  530  control each stepping motor  532  to rotate individually.  FIG. 5B  is an enlarged diagram of a connection between the stepping motor  532  and the serial connection device. 
     In another embodiment of the multi-directional flat speaker device, not only a control mechanism can be utilized to control serially connected thin-type flat speakers to send sounds individually to directions preset by a user, but baffles can also be added, as illustrated in  FIG. 6A , to enhance directional effects of the flat speakers. As illustrated in  FIG. 6A , a multi-directional flat speaker device  600  includes a plurality of flat speakers with directional effects  611 ,  612 ,  613  and  614 , for example, and surfaces thereof include a plurality of sound holes. A plurality of serial connection devices  620 ,  621 ,  622 ,  623 ,  624  and  625  is serially connected to a plurality of corresponding flat speakers  611 ,  612 ,  613  and  614  respectively so as to drive the serially connected flat speakers to rotate. In order to enhance the directional effects of the flat speakers, increase reflectivity of sounds, or prevent interferences between adjacent speakers, the multi-directional speaker device  600  is joined with baffles  630  and  632  for increasing the sound reflectivity or preventing the interferences between the adjacent speakers. The baffles  630  and  632  respectively include serial connection devices  620  and  625  for control mechanisms to control rotations thereof. 
     A disposition of the serial connection devices  620 ,  621 ,  622 ,  623 ,  624  and  625  being serially connected to the corresponding flat speakers  611 ,  612 ,  613  and  614  can be disposed in a linear manner, an annular manner or a half-annular manner with a specific radian. The disposition is designed based on demands of actual products or different disposing locations of the multi-directional flat speaker devices. For instance, referring to  FIG. 6B , the method of serially connecting the serial connection devices  620 ,  621 ,  622 ,  623 ,  624  and  625  utilizes the radian design of a half-annular. 
     A supporting mechanism between the thin-type flat speakers and the serial connection devices can be disposed at an edge or a specific location of the flat speaker. For example, referring to  FIG. 7A  and  FIG. 7B , supporting rods  720 ,  721  and  722 ,  723  are respectively located on two sides of flat speakers  710  and  712 . A revolver  730  is controlled by a control mechanism, such that the flat speakers  710  and  712  can be rotated to different angles, for example, 0-180°, through the revolver  730 . As shown in  FIG. 7B , if the flat speaker  712  is present, then the two sides thereof include supporting rods  722  and  723 . Hence, the flat speakers  722  and  723  can be rotated to different angles, for example, from 0 degree to 360 degrees, through the revolver  730 . 
     In addition, an assembly of the flat speaker and the serial connection device can be referred to  FIG. 8 . The supporting mechanism utilizes an assembling method as illustrated in the diagram, or a mechanism fixing or bonding method to perform the assembly. A serial connection device  820  has a bar-shaped hole for inserting a flat speaker  810 . The flat speaker  810  is slid into the bar-shaped hole from a side to be fixed or pulled out to be disassembled. 
     A control mechanism for controlling the thin-type flat speakers can control individual speakers to face a same direction or different directions. The control mechanism can be a method of assembling an electrical circuit and a mechanical mechanism, or simply a method of assembling a mechanical mechanism. In addition, a method of linking serial connected thin-type flat speakers can apply transmission lines for transmitting audio signals, or an external facilitating mechanism. 
     The multi-directional flat speaker device includes an audio input interface for receiving one or a plurality set(s) of audio signals. Herein, the audio signals can be identical signals or a plurality of processed divided signals that is provided to different flat speakers. Therefore, the flat speakers with directivity can be individually driven to output the processed divided signals from an audio end to different directions. Thus, a specific sound field effect design can be achieved. 
     Moreover, a structure of the flat speaker aforementioned, referring to  FIG. 9 , is assembled by a plurality of speaker unit structures  900  in one embodiment. The speaker unit structure  900  forms a working region of a vibrating film between adjacent supporting bodies on two sides, that is, a cavity space for the speaker to generate resonant sound field is formed. The interior of the speaker unit structure  900  is disposed with a plurality of specifically designed supporting bodies. Here, the supporting bodies are specifically designed for the configuration or the manner of disposition. Moreover, a design of a sound cavity structure provided in the embodiment faces the rear of the sound making direction. A working region of the vibrating film is formed between the sound cavity substrate and the vibrating film through the adjacent sound cavity supporting bodies, that is, another cavity space of the speaker for generating a resonant sound field is formed. 
     The speaker unit structure  900  includes a vibrating film  910 , an electrode layer  920  with a plurality of holes, a frame supporting body  930 , and a plurality of supporting bodies  940  between the electrode layer  920  and the vibrating film  910 . A sound cavity structure is present on a side that is opposite to the side of the vibrating film  910  facing the electrode layer  920 . The sound cavity structure is assembled by a sound cavity substrate  960  and a plurality of sound cavity supporting bodies  970 , which is disposed between the vibrating film  910  and the sound cavity substrate  960 . The vibrating film  910  includes an electret layer  912  and a metal thin film electrode  914 . Herein, a side surface  912   a  of the electret layer  912  is connected to the frame supporting body  930  and the supporting bodies  940 . Moreover, another side surface  912   b  is electrically connected to the metal thin film electrode  914 . 
     The electrode layer  920  having a plurality of holes can be assembled by metal material. In one embodiment, flexible material, such as paper or ultra-thin non-conductive material layer, can also be applied by plating a layer of metal thin film on a surface thereof. 
     When the electrode layer  920  is a non-conductive material being plated with a layer of metal thin film, the non-conductive material can be non-conductive material such as plastic, rubber, paper, non-conductive fabric (cotton fiber, high polymer fiber), etc, and the metal thin film can be pure metal material such as aluminum, gold, silver, copper, an alloy thereof, bi-metal material such as Ni/Au, one of indium tin oxide (ITO) or indium zinc oxide (IZO) or a combination thereof, or high polymer conductive material PEDOT, etc. 
     In another embodiment, when the electrode layer  920  is assembled by conductive material, the electrode layer  920  can be assembled by one of metal (iron, copper, aluminum, etc, or an alloy thereof) and conductive fabric (metal fiber, metal oxide fiber, carbon fiber, graphite fiber). 
     A material of the electret layer  912  can be dielectric material. The dielectric material can maintain static charges for a long time after being electrized, and can generate ferroelectric effect therein after being charged, and is thus called the electret vibrating film layer. The electret layer  912  can be fabricated by mono-layer or multi-layer dielectric material, and the dielectric material can be, for example, fluorinated ethylenepropylene (FEP), polytetrafluorethylene (PTFE), polyvinylidene fluoride (PVDF), some Fluorine Polymer, and other suitable materials. Additionally, the interior of the dielectric material includes micro or micro nano-pores. The electret layer  912  is a vibrating film capable of maintaining the static charges and piezoelectricity for a long time after the dielectric material is electrized, and includes micro nano-pores to increase the transmittance and piezoelectric characteristics. Thus, after being charged by corona, dipolar charges are generated in the material to generate the ferroelectric effect. In order not to affect the tension and vibration effects of the vibrating film  910 , the metal thin film electrode  914  may be an ultra-thin metal thin film electrode. The thickness of the defined “ultra-thin” herein is between about 0.2 μm (micrometer, μm) and 0.8 mm (millimeter, mm), and the preferred thickness is between about 0.2 μm and 0.4 μm in an embodiment, which may be approximately 0.3 μm. 
     The electret layer  912  that is fully injected with negative charges is set as an example for illustration. The input audio signals are respectively connected to the electrode layer  920  having the plurality of holes and the metal thin film electrode  914 . When the input audio signal is a positive voltage, it generates an attractive force with the negative charges of the electret vibrating film on the speaker unit. When the audio signal is a negative voltage, it generates a repulsive force with the positive charges on the speaker unit, so as to cause the movement of the vibrating film  910 . 
     On the contrary, when the voltage-phase input of the audio signal has changed, the positive voltage similarly generates an attractive force with the negative charges of the electret vibrating film on the speaker unit while the negative voltage generates a repulsive force with the positive charge on the unit, and the vibrating film  910  moves towards an opposite direction. When the electret vibrating film  910  moves towards different directions, it generates sound output by means of compressing the surrounding air. 
     As for the speaker unit structure  900  in this embodiment, a thin film  950  with air-permeable and water-proofing characteristics may be wrapped on one or two sides thereof, for example, GORE-TEX thin film made of expanded PTFE (ePTFE) material, which can prevent influences caused by water and oxidation that may result in the leakage of the charges of the electret layer  912  and thus affecting the ferroelectric effect. 
     A working region of the vibrating membrane  910  is formed between the electrode layer  920  and the vibrating membrane  910  through the adjacent supporting bodies  940 , that is, a cavity space  942  of the speaker for generating a resonant sound field is formed. A working region of the vibrating membrane  910  is formed between the electrode layer  960  and the vibrating membrane  910  through the adjacent supporting bodies  970 , that is, a cavity space  972  of the speaker for generating a resonant sound field is formed. No matter for the supporting bodies  940  or the sound cavity supporting bodies  970 , the disposing manner, the height, and other designs may be adjusted according to the requirements on design. In addition, the number of the sound cavity supporting bodies  970  may be equal to, less than, or more than that of the supporting bodies  940 . The supporting bodies  940  or the sound cavity supporting bodies  970  may be respectively fabricated on the electrode layer  920  or the sound cavity substrate  960 . 
     The sound cavity structure provided in the embodiment is disposed on a surface of the metal thin film electrode  914  of the vibrating film  910 . The optimal design of supporting bodies or material of disposing sound absorbing cotton are disposed according to the consideration of the frequency design of the speaker. Here, the disposing manner, the height, and other designs may be adjusted, and the configuration thereof can be of random shapes. Moreover, the cavity space formed by the frame supporting body at the location of the sound cavity structure may optionally include a sound releasing hole  972  for releasing the pressure from generating sounds to produce a better sound field effect. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the embodiment without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the embodiment cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.