1. Field of the Invention
The present invention relates to electrostatic speakers (or capacitor speakers) constituted of parallel planar electrodes and diaphragms.
The present application claims priority on Japanese Patent Application No. 2009-228543, the content of which is incorporated herein by reference.
2. Description of the Related Art
Patent Document 1 discloses an electrostatic speaker in which a diaphragm having conductivity is slightly distanced from and interposed between a pair of fixed electrodes having conductivity, which are disposed opposite to each other. Patent Document 2 discloses a planar speaker in which a pair of planar electrodes is disposed in proximity to the surface and backside of a diaphragm (i.e. a thin-film member) via damping members.
Patent Document 1: Japanese Patent Application Publication No. 2007-274341
Patent Document 2: Japanese Patent Application Publication No. 2008-54154
The technologies of Patent Documents 1 and 2 may not always demonstrate a normal functionality as an electrostatic speaker when adjacent conductive layers unexpectedly conduct to each other due to a wrong installation of an electrostatic speaker. Even when an electrostatic speaker is installed with a holding member tightly holding end portions thereof, the electrostatic speaker may not function normally due to a short-circuiting of adjacent conductive layers under a high pressure applied to end portions thereof. Even when an electrostatic speaker is installed with a holding member having conductivity (e.g. a screw or hook) being inserted into a through-hole (which runs through the electrostatic speaker), the electrostatic speaker may not function normally due to a short-circuiting of adjacent conductive layers (which are partially exposed on the interior wall of a through-hole) being pressed by a holding member, In addition, a high pressure applied to the periphery of a through-hole may cause a short-circuiting of adjacent conductive layers, thus disturbing a normal function of an electrostatic speaker.
It is an object of the present invention to provide an electrostatic speaker which does not cause a short-circuiting of adjacent conductive layers regardless of installation using various types of holding members.
An electrostatic speaker of the present invention is constituted of a diaphragm in which a first conductive layer is formed on a first surface, and an electrode in which a second conductive layer is formed on a second surface. The diaphragm is disposed opposite to and/or slightly distanced from the electrode in such a way that the first surface is disposed opposite to the second surface. A holding region is formed on the main body of an electrostatic speaker in relation to the first surface of the diaphragm and the second surface of the electrode. The first conductive layer circumvents the holding region of the first surface whilst the second conductive layer circumvents the holding region of the second surface.
In the above, the holding region is formed along a predetermined edge of the main body of an electrostatic speaker. That is the holding region is formed on the first surface along the predetermined edge whilst the holding region is formed on the second surface along the predetermined edge.
In addition, a through-hole can be formed to run through the diaphragm and the electrode. The holding region of the first surface is formed in the periphery of a through-hole running through the diaphragm, whilst the holding region of the second surface is formed in the periphery of a through-hole running through the electrode,
The installation equipment is adapted to the electrostatic speaker in such a way that a holding member holds the holding region of the electrostatic speaker, thus installing the electrostatic speaker at a predetermined position (e.g. a wall surface). The present invention guarantees the normal functionality of an electrostatic speaker irrespective of installation measures. Even when a through-hole of an electrostatic speaker is hung at a predetermined position via a holding member, the present invention guarantees normal functionality of the electrostatic speaker.
These and other objects, aspects, and embodiments of the present invention will be described in more detail with reference to the following drawings.
The present invention will be described in further detail by way of examples with reference to the accompanying drawings.
The electrostatic speaker 10 is constituted of an electrode 112, a diaphragm 102, an electrode 114, and a pair of cushion materials 132. The electrostatic speaker 10 has a laminated structure sequentially laminating the electrode 112 (i.e. an uppermost portion), the cushion material 132, the diaphragm 102, the cushion material 132, and the electrode 114 (i.e. a lowermost portion), which are mutually connected together via tapes or bonds (or adhesives). The electrostatic speaker 10 has an integral structure including these constituent elements as shown in
A main body of the electrostatic speaker 10 has a holding region 10A, which is held by a holding member (not shown) in an installation of the electrostatic speaker 10. The holding region 10A is laid along an edge of the main body of the electrostatic speaker 10. That is, the holding region 10A having a width W is formed along one side of the electrostatic speaker 10 having a rectangular shape.
The diaphragm 102 is sandwiched between the electrodes 112 and 114 via the cushion materials 132 with one end portion thereof being held between the electrodes 112 and 114, One cushion material 132 is interposed between the diaphragm 102 and the electrode 112, while the other cushion material 132 is interposed between the diaphragm 102 and the electrode 114. The cushion materials 132 have insulating property, air permeability, and elasticity. The cushion materials 132 are composed of compressed cottons. An internal space 10B which allows for an upper-side vibration of the diaphragm 102 is secured between the diaphragm 102 and the electrode 112, while another internal space 10B which allows for a lower-side vibration of the diaphragm 102 is secured between the diaphragm 102 and the electrode 114. It is possible to insert a spacer between the diaphragm 102 and the electrode 112, thus securing the internal space 10B therebetween. In addition, it is possible to insert a spacer between the diaphragm 102 and the electrode 114, thus securing the internal space 10B therebetween.
A vibrating portion of the diaphragm 102 other than one edge thereof has a shape and size which can be stored inside the internal space 10B. The vibrating portion of the diaphragm 102 is disposed approximately at an intermediate position of the internal space 10B in a vertical direction and interposed between the electrodes 112 and 114. An upper surface 102A of the diaphragm 102 is disposed opposite to a lower surface 112A of the electrode 112 via the internal space 10B which is sufficiently large to accept an upper-side vibration of the diaphragm 102. A lower surface 102B of the diaphragm 102 is disposed opposite to an upper surface 114A of the electrode 114 via the internal space 10B which is sufficiently large enough to accept a lower-side vibration of the diaphragm 102.
A conductive layer 103 is formed on the upper surface 102A of the diaphragm 102, while a conductive layer 104 is formed on the lower surface 102B of the diaphragm 102. A conductive layer 113 is formed on the lower surface 112A of the electrode 112, while a conductive layer 115 is formed on the upper surface 114A of the electrode 114. The conductive layers 103, 104, 113, and 115 are formed on the surfaces 102A, 102B, 112A, and 114A in such a way that conductive metals are deposited on these surfaces or conductive coatings are applied onto these surfaces.
As described above, the holding region 10A is formed along one edge of the electrostatic speaker 10 with the predetermined with W; that is, the holding region 10A having the width W is formed along one edge of the upper surface 102A of the diaphragm 102 and is also formed along one edge of the lower surface 102B of the diaphragm 102. In addition, the holding region 10A having a width W is formed along one edge of the lower surface 112A of the electrode 112 and is further formed along one edge of the upper surface 114A of the electrode 114.
The electrostatic speaker 10 is designed to satisfy at least one of design choices (a) and (b).
(a) The conductive layer 103 is formed to bypass the holding region 10A on the upper surface 102A of the diaphragm 102.
(b) The conductive layer 113 is formed to bypass the holding region 10A on the lower surface 112A of the electrode 112.
Specifically, the conductive layer 103 is not formed in the holding region 10A on the upper surface 102A of the diaphragm 102, so that the conductive layer 103 bypasses the holding region 10A of the upper surface 102A. The conductive layer 113 is not formed in the holding region 10A on the lower surface 112A of the electrode 112, so that the conductive layer 113 bypasses the holding region 10A of the lower surface 112A.
The electrostatic speaker 10 is designed to satisfy at least one of design choices (c) and (d).
(c) The conductive layer 104 is formed to bypass the holding region 10A on the lower surface 102B of the diaphragm 102.
(d) The conductive layer 115 is formed to bypass the holding region 10A on the upper surface 114A of the electrode 114.
That is, the conductive layer 104 is not formed in the holding region 10A on the lower surface 1028 of the diaphragm 102, so that the conductive layer 104 bypasses the holding region 10A of the lower surface 102B. The conductive layer 115 is not formed in the holding region 10A on the upper surface 114A of the electrode 114, so that the conductive layer 115 bypasses the holding region 10A of the upper surface 114.
For example, a positive voltage is applied to the conductive layers 103 and 104, wherein a positive voltage is applied to the conductive layer 113 while a negative voltage is applied to the conductive layer 115. In this situation, the diaphragm 102 is displaced toward the conductive layer 115 in such a way that the conductive layers 103 and 104 sandwiching the diaphragm 102 are repelled by the “positively charged” conductive layer 113 while being attracted toward the “negatively charged” conductive layer 115. Alternatively, a positive voltage is applied to the conductive layers 103 and 104, wherein a negative voltage is applied to the conductive layer 113 while a positive voltage is applied to the conductive layer 115. In this situation, the diaphragm 102 is displaced toward the conductive layer 113 in such a way that the conductive layers 103 and 104 are repelled by the conductive layer 115 while being attracted toward the conductive layer 113. The diaphragm 102 is forced to vibrate as the conductive layers 103 and 104 repeat displacements toward the conductive layers 113 and 115. The diaphragm 102 vibrates to produce sound based on vibration factors (i.e. frequency, amplitude, and phase). Sound caused by the diaphragm 102 permeates at least one of the apertures 112C of the electrode 112 and the apertures 114C of the electrode 114, so that the electrostatic speaker 10 emits sound into the external space.
In the second embodiment, through-holes 10C pierce through the main body of the electrostatic speaker 10 from the upper surface of the electrode 112 to the lower surface of the electrode 114, That is, the through-holes 10C run through the electrode 112, the diaphragm 102, and the electrode 114.
The conductive layer 103 is not formed in the holding regions 10D on the upper surface 102A of the diaphragm 102; hence, the conductive layer 103 circumvents the holding regions 10D of the upper surface 102A of the diaphragm 102. In addition, the conductive layer 104 is not formed in the holding regions 10D on the lower surface 102E of the diaphragm 102; hence, the conductive layer 104 circumvents the holding regions 10D of the lower surface 102B of the diaphragm 102.
The conductive layer 113 is not formed in the holding regions 10D on the lower surface 112A of the electrode 112; hence, the conductive layer 113 circumvents the holding regions 10D of the lower surface 112A of the electrode 112. In addition, the conductive layer 115 is not formed in the holding regions 10D on the upper surface 114A of the electrode 114; hence, the conductive layer 115 circumvents the holding regions 10D of the upper surface 114A of the electrode 114.
The present invention is not necessarily limited to the first and second embodiments, which can be further modified in various ways as follows.
(1) The structure of the electrostatic speaker 10 is not necessarily limited to the first and second embodiments. In short, the electrostatic speaker 10 needs to be configured of a diaphragm having a first conductive layer on a first surface and a substrate having a second conductive layer on a second surface. Namely, the electrostatic speaker 10 needs at least the diaphragm 102 having the conductive layer 103 on the upper surface 102A and the electrode 112 having the conductive layer 113 on the lower surface 112A. In addition, the diaphragm 102, the electrode 112 and 114 do not need conductivity in the holding region 10A and the holding regions 10D, whilst they need conductivity in other regions (other than the holding regions 10A and 10D). For example, at least one of the electrodes 112 and 114 is composed of a planar conductive cloth in which conductive materials are included in other regions (other than the holding regions 10A and 10D), whilst no conductive materials are included in the holding regions 10A and 10D.
(2) It is possible to adopt other materials other than PET and PP for use in the diaphragm 102, the electrodes 112 and 114. For example, the diaphragm 102, the electrodes 112 and 114 can be composed of synthetic resins. The cushion materials 132 need air permeability and elasticity; hence, they are not necessarily composed of compressed cottons. For example, the cushion materials 132 can be composed of ester wools. The outline shapes of the diaphragm 102, the electrode 112 and 114 are not necessarily limited to rectangular shapes. For example, the diaphragm 102, the electrodes 112 and 114 can be formed in circular shapes or polygonal shapes except for rectangular shapes. In addition, the main body of the electrostatic speaker 10 can be formed in a cylindrical shape, a conical shape, a pyramid shape, a lampshade shape, or parasol shape. In this case, it is preferable that one holding region be formed at one end of the cylindrical shape, whilst one holding region be formed at a top portion of the conical shape, the pyramid shape, the lampshade shape, or the parasol shape.
(3) It is possible to incorporate terminals with respect to the holding member 510 and the electrostatic speaker 10. The terminal of the electrostatic speaker 10 comes in contact with the terminal of the holding members 510 when the electrostatic speaker 10 is held by the holding member 510. The terminal of the electrostatic speaker 10 coupled with the terminal of the holding member 510 may serve as a power-supply terminal for supplying power to any one of the conductive layers 10, 104, 113, and 115. It is possible to incorporate a plurality of terminals (each serving as the above power-supply terminal) with respect to the electrostatic speaker 10 and the holding member 510 respectively. That is, it is possible to incorporate four power-supply terminals for supplying power to the four conductive layers 103, 104, 113, and 115 with respect to the electrostatic speaker 10 and the holding members 510 respectively.
(4) In the first embodiment, the holding region 10A is not necessarily formed along one edge of the “rectangular-shaped” electrostatic speaker 10, and the holding region 10A is not necessarily formed with a certain width. For example, the position, shape and size of the holding region 10A can be determined in conformity with the position, shape and size of the holding member 510 holding the electrostatic speaker 10. The holding member 510 does not necessarily hold the upper edge of the electrostatic speaker 10, wherein the holding member 510 can hold both the left-side and right-side edges, both the upper and lower edges of the electrostatic speaker 10, all the four corners of the electrostatic speaker 10, all the four sides of the electrostatic speaker 10, or the like. Herein, the holding region 10A needs to be set to the position at which the holding region 10A is held by the holding member 510. The length of the holding member 510 can be shorter than the length of one side of the electrostatic speaker 10. In this case, the length of the holding region 10A needs to agree with the length of the holding member 510 along a side edge of the electrostatic speaker 10 being held by the holding member 510.
(5) The electrostatic speaker 10 of the first embodiment needs to be configured such that adjacent conductive layers cannot be short-circuited in the holding region 10A. In other words, no conductivity is needed in at least one of the upper surface 102A of the diaphragm 102 and the lower surface 112A. of the electrode 112. In addition, no conductivity is needed in at least one of the lower surface 102E of the diaphragm 102 and the upper surface 114A of the electrode 114. That is, one of the conductive layers 103 and 113 is not necessarily formed in the holding region 10A. In addition, one of the conductive layers 104 and 115 is not necessarily formed in the holding region 10A. Alternatively, an insulating layer can be formed in the holding region 10A in order to cover one of the conductive layers 103 and 113 therewith. In addition, an insulating layer can be formed in the holding region 10A in order to cover one of the conductive layers 104 and 115 therewith.
(6) In the second embodiment, the through-holes 10C are not necessarily formed in rectangular shapes in plan view. The through-holes IOC can be formed in circular shapes or polygonal shapes except for rectangular shapes, The number of the through-holes 10C formed in the main body of the electrostatic speaker 10 is not necessarily limited to two. It is possible to form one through-hole 10C or three or more through-holes 10C in the main body of the electrostatic speaker 10. The holding regions 10D are not necessarily formed in rectangular shapes in plan view. The holding regions 10D can be formed in circular shapes or polygonal shapes except for rectangular shapes. The shapes of the holding regions 10D do not necessarily agree with the shapes of the through-holes 10C. The shape, position and size of the holding region 10D can be determined in conformity with the shape, position and size of the holding member 510 holding the electrostatic speaker 10. The holding region 10D can be set to a position at which the holding member 510 holds the electrostatic speaker 10.
(7) In the second embodiment, an installation measure of the electrostatic speaker 10 having the through-holes 10C is not necessarily limited to the “L-shaped” holding members 510 shown in
(8) In the second embodiment, the electrostatic speaker 10 does not necessarily equipped with the through-holes 10C in shipment. The electrostatic speaker 10 subjected to shipment can have the holding regions 10D which do not surround the through-holes 10C. This allows users to arbitrarily form the through-holes 10C used for fixing the electrostatic speaker 10 onto the wall surface 920. Before an installation of the electrostatic speaker 10 on the wall surface 920, users may form the through-holes 10C in the holding regions 10D by use of a drill or punch in advance. Alternatively, users may form the through-holes 10C simultaneously with fixing the electrostatic speaker 10 onto the wall surface 920, wherein users may hammer nails into the holding regions 10B of the electrostatic speaker 10.
(9) It is possible to form an identification mark indicating the holding region 10A or 10D on the surface of the electrostatic speaker 10. For example, the holding region 10A or 10D can be painted in a color which differs from a color of the other region on the surface of the electrostatic speaker 10. Alternatively, the holding region 10A or 10D can be formed with a surface shape (or a texture) which differs from the texture of the other region on the surface of the electrostatic speaker 10, This helps users to easily discriminate position, shape and size of the holding member 510 holding the electrostatic speaker 10.
Lastly, the present invention is not necessarily limited to the above embodiments and variations, which can be further modified within the scope of the invention as defined in the appended claims.
Number | Date | Country | Kind |
---|---|---|---|
2009-228543 | Sep 2009 | JP | national |