Electroacoustic transducer

Abstract

To provide an electroacoustic transducer in which a vibrating membrane is less likely to be broken and sound pressure is improved even when the transducer is small.SOLUTION: An electroacoustic transducer 2 includes a housing 20, a partition member 30 disposed inside the housing 20, a first electroacoustic conversion unit 100, and a second electroacoustic conversion unit 200. The electroacoustic conversion unit of a first (2) includes a fixed electrode 101(201), a vibrating film 105(205) which is disposed to face the fixed electrode and vibrates according to a potential difference generated between the fixed electrode and the fixed electrode based on an electric signal, and a support member 107(207) which supports a partial region of the vibrating film and brings a part of the vibrating film into contact with the fixed electrode. The first electroacoustic conversion unit and the second electroacoustic conversion unit are disposed to face each other with the partition member 30 interposed therebetween so that a sound emitting part 100a and a sound emitting part 200a communicate with an acoustic outlet 2a, and the partition member 30 supports the support member 107 and the support member 207.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an electro-acoustic transducer that converts an electrical signal into sound. [Background technology]

[0002] Conventionally, there has been known a capacitive electroacoustic transducer having a flat fixed electrode (hereinafter referred to as a fixed pole) and a diaphragm provided opposite the fixed pole. Patent Document 1 discloses a capacitor-type earphone in which the outer periphery of a thin-film diaphragm is fixed to a housing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-183851 Summary of the Invention [Problem to be solved by the invention]

[0004] In electroacoustic transducers such as capacitor-type earphones or headphones, the pressure inside the electroacoustic transducer changes as the pressure inside the ear canal changes depending on how the device is worn. If the pressure inside the electroacoustic transducer changes while the diaphragm is fixed to the housing only at its outer periphery, the diaphragm will be displaced, causing stress to concentrate on the outer periphery of the diaphragm. It is desirable for the electroacoustic transducer to have a structure that makes the diaphragm less susceptible to damage due to stress applied to the outer periphery, and that can improve the sensitivity (sound pressure) of the electroacoustic transducer even if it is small.

[0005] Therefore, the present invention has been made in consideration of these points, and aims to provide an electro-acoustic transducer in which the vibrating membrane is less likely to be damaged and in which the sensitivity of the electro-acoustic transducer is less likely to decrease even if it is small. [Means for solving the problem]

[0006] The electroacoustic transducer of the present invention comprises a housing having an acoustic outlet for releasing sound to the outside, a partition member arranged inside the housing, a first electroacoustic conversion unit arranged inside the housing, and a second electroacoustic conversion unit arranged inside the housing, wherein the first electroacoustic conversion unit and the second electroacoustic conversion unit each have a fixed pole, a vibrating membrane arranged opposite the fixed pole and vibrating in response to a potential difference generated between the fixed pole and the vibrating membrane based on an electric signal, and a support member that supports a partial area of ​​the vibrating membrane and abuts a part of the vibrating membrane against the fixed pole, and are arranged so that the distance between the vibrating membrane and the fixed pole increases as the distance from the partial area increases outward, and the sound emitting portion of the first electroacoustic conversion unit and the sound emitting portion of the second electroacoustic conversion unit are arranged opposite each other across the partition member so as to communicate with the acoustic outlet, and the partition member supports the support member of the first electroacoustic conversion unit and the support member of the second electroacoustic conversion unit.

[0007] The partition member may have a first recess formed on a first surface that defines a portion of the acoustic space of the first electroacoustic conversion unit, and that receives and supports the support member of the first electroacoustic conversion unit, and a second recess formed on a second surface that defines a portion of the acoustic space of the second electroacoustic conversion unit, and that receives and supports the support member of the second electroacoustic conversion unit.

[0008] The partition member may be provided to divide the interior of the housing into a first space and a second space.

[0009] The partition member may be a plate-like member having a through hole formed therein, one opening of which is exposed to the first space and the other opening of which is exposed to the second space.

[0010] The housing may be cylindrical, and the sound outlet may be formed in a side surface of the housing.

[0011] The first electroacoustic conversion unit and the second electroacoustic conversion unit may be arranged at an angle so that the distance between them gradually decreases from the end of the housing on the side where the acoustic outlet is located to the end opposite the acoustic outlet in a cross section of the housing cut in the thickness direction.

[0012] The housing may include a cylindrical housing member, a first cover member attached to one end of the housing member, and a second cover member attached to the other end of the housing member. [Effects of the Invention]

[0013] The present invention has the effect of providing an electroacoustic transducer in which the diaphragm is less likely to be damaged and in which the sensitivity of the electroacoustic transducer is less likely to decrease even if the transducer is small. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view of an earphone, which is an example of an electroacoustic transducer. [Figure 2] FIG. 2 is a diagram showing the appearance of the earphone of FIG. [Figure 3] 2 is a cross-sectional view showing the electro-acoustic transducer of the earphone of FIG. 1, showing a cross section cut in the thickness direction of the housing. [Figure 4] FIG. 2 is a cross-sectional view showing a housing of the electroacoustic transducer. [Figure 5] FIG. 1 is a schematic diagram showing a model of the configuration of an electroacoustic transducer. [Figure 6] FIG. 2 is a perspective view illustrating the internal structure of a housing of the electroacoustic transducer. [Figure 7] FIG. 2 is a diagram showing an electrical circuit for inputting an electrical signal to a fixed electrode and a vibrating membrane. [Figure 8] FIG. 1 is a cross-sectional view schematically showing a push-pull type electro-acoustic transducer. [Figure 9] FIG. 4 is a cross-sectional view showing the configuration of an electroacoustic transducer according to a second embodiment. [Figure 10]FIG. 10 is a perspective view showing a state in which an earphone having an electro-acoustic transducer according to a second embodiment is worn by a user. DETAILED DESCRIPTION OF THE INVENTION

[0015] [First embodiment] An electroacoustic transducer according to an embodiment of the present invention and an electroacoustic transducer device including the electroacoustic transducer will be described with reference to the drawings. Fig. 1 is a cross-sectional view of an earphone 1, which is an example of an electroacoustic transducer. Fig. 2 is a diagram showing the appearance of the earphone 1 of Fig. 1.

[0016] The present invention can be applied to both so-called in-ear type earphones and inner-ear type earphones, but the following will illustrate an in-ear type earphone. The external shape of the earphone 1 in Figure 1 is partially different from the external shape of the earphone 1 in Figure 2, but these differences are not essential.

[0017] In the following, terms indicating directions such as "upper," "lower," "right," and "left" are used in accordance with the orientation of objects depicted in the drawings, but these terms are not intended to limit the present invention. The "upper" and "lower" directions correspond to the thickness direction of the electro-acoustic transducer, and the "right" and "left" directions correspond to directions across the electro-acoustic transducer.

[0018] (Outline of electroacoustic transducer) As shown in FIGS. 1 and 2, the earphone 1 includes an electro-acoustic transducer 2, an earpiece 3, a conduit forming member 4, and a cable 5.

[0019] The electroacoustic transducer 2 is a driver unit that converts electrical signals into sound. The internal structure of the electroacoustic transducer 2 will be described in detail later. The earpiece 3 is a component that is inserted into the user's ear canal and is made of an elastic material.

[0020] The conduit forming member 4 forms part of the outer shape of the earphone 1. The conduit forming member 4 has a conduit portion 4a and a cable connection portion 4b. The conduit portion 4a is a cylindrical structural portion for emitting sound generated by the electro-acoustic transducer 2 to the outside, and has a duct 4c formed therein. The earpiece 3 is attached to the tip of the conduit portion 4a.

[0021] The cable connection portion 4b is a portion to which the cable 5 is connected. The cable 5 is a cable that transmits an electric signal to the electro-acoustic transducer 2.

[0022] In this embodiment, the conduit-forming member 4 and the electroacoustic transducer 2 are described as separate components, but this does not mean that the conduit-forming member 4 and the electroacoustic transducer 2 must be provided separately. The conduit-forming member 4 and the electroacoustic transducer 2 may be provided integrally as a single member.

[0023] (Configuration of electroacoustic transducer) Fig. 3 is a cross-sectional view showing the electro-acoustic transducer 2 of the earphone 1 of Fig. 1, showing a cross section of the housing cut in the thickness direction. Fig. 4 is a cross-sectional view showing the housing of the electro-acoustic transducer 2. Fig. 5 is a schematic diagram showing a model of the configuration of the electro-acoustic transducer 2. Fig. 6 is a perspective view for explaining the internal structure of the housing of the electro-acoustic transducer 2. Fig. 7 is a diagram showing an electric circuit for inputting an electric signal to the fixed electrode and the diaphragm.

[0024] As shown in FIG. 3, the electroacoustic transducer 2 has a housing 20, a partition member 30, a first electroacoustic transducer unit 100, and a second electroacoustic transducer unit 200.

[0025] One of the features of the electroacoustic transducer 2 is that, as shown in FIGS. 3 and 5, the first electroacoustic transducer unit 100 and the second electroacoustic transducer unit 200 are arranged facing each other within the housing 20, sandwiching the partition member 30. Sound generated by each of the first electroacoustic transducer unit 100 and the second electroacoustic transducer unit 200 is released to the outside from a sound outlet 2a on the side of the housing 20. This configuration of the electroacoustic transducer 2 increases the effective area of ​​the diaphragm compared to a case where only one electroacoustic transducer unit is included. As a result, even if the housing 20 is small, the sensitivity of the electroacoustic transducer 2 is improved, resulting in the advantageous effect of improving the sound quality of the earphone 1.

[0026] The first electroacoustic transducer unit 100 and the second electroacoustic transducer unit 200 have the same configuration and are arranged symmetrically with respect to a reference plane A that crosses the center of the thickness direction of the electroacoustic transducer 2. The components of the first electroacoustic transducer unit 100 are assigned numbers in the "100" series, and the components of the second electroacoustic transducer unit 200 are assigned numbers in the "200" series that correspond to the components of the first electroacoustic transducer unit 100. Below, the first electroacoustic transducer unit 100 will be described, and a duplicated description of the second electroacoustic transducer unit 200 will be omitted. The two electroacoustic transducer units 100, 200 may be simply referred to as "electroacoustic transducer units" without any particular distinction being made between them.

[0027] (Housing structure) Before describing the detailed configuration of the electroacoustic transducer unit, we will first describe the housing 20. As shown in Figures 3 and 4, the housing 20 has a housing member 21, a first cover member 25, and a second cover member 26. The housing 20 is also formed symmetrically in the up-down direction with respect to the reference plane A.

[0028] The housing member 21 is a cylindrical member. One end, which is the upper end, of the housing member 21, and the other end, which is the lower end, are open. The housing member 21 constitutes the side surface of the housing 20. The housing member 21 is formed of, for example, a resin material. A first cover member 25 is attached to the upper end of the housing member 21, and a second cover member 26 is attached to the lower end of the housing member 21. The housing member 21 is formed with a sound outlet 2a that releases sound to the outside.

[0029] The first cover member 25 is a member that closes the opening at the upper end of the housing member 21. As shown in Fig. 4, the first cover member 25 has a disk-shaped flat surface 25a and side surfaces 25b that extend from the peripheral edge of the flat surface 25a in a direction perpendicular to the flat surface 25a. The first cover member 25 is formed of, for example, a resin material.

[0030] The second cover member 26 is a member that closes the opening at the lower end of the housing member 21. The second cover member 26 also has a disk-shaped flat surface 26a and a side surface 26b that extends from the peripheral edge of the flat surface 26a in a direction perpendicular to the flat surface 25a. The second cover member 26 is formed of, for example, a resin material.

[0031] A sealed internal space is formed by attaching the first cover member 25 and the second cover member 26 to the housing member 21. The outer shape of the housing 20 is a slightly flattened cylinder with a height dimension shorter than its diameter. As can be seen from the perspective view of FIG. 2, the flat surface 25a of the first cover member 25 is the surface that faces the side of the user's head when the earphone 1 is in use. Note that, although a cylindrical housing 20 is exemplified in this embodiment, the shape of the housing 20 is arbitrary. Holes for adjusting acoustic characteristics may be formed in either or both of the first cover member 25 and the second cover member 26.

[0032] 3 and 4 again. Partition member 30 is disposed inside housing 20. Specifically, partition member 30 is a member that divides the internal space of housing 20 into a first space S100 and a second space S200. Partition member 30 may be provided as a member separate from housing member 21, but in this embodiment, it is formed integrally with housing member 21. Partition member 30 is a disk-shaped member and is disposed coaxially with housing 20 such that its central axis coincides with the central axis CL of housing 20.

[0033] 4 and 6, the partition member 30 has a first surface 31a that defines a part of the first space S100 and a second surface 31b that is located on the opposite side and defines a part of the second space S200. The first surface 31a and the second surface 31b may be surfaces that are inclined with respect to the reference plane A, or may be surfaces that are parallel to the reference plane A.

[0034] Specifically, the partition member 30 has a circular thick portion 30-1 and an annular portion 30-2 formed on the outside thereof. The thick portion 30-1 is formed in a circular region of a predetermined radius centered on the central axis CL. The annular portion 30-2 has an annular flat surface. As will be described later, a conductive member 113 and the like are disposed in the annular portion 30-2.

[0035] The partition member 30 has a recess 33, which is a first recess, formed on the first surface 31a. The partition member 30 also has a recess 33 formed on the second surface 31b (see FIG. 3). Each recess 33 is a structural part for receiving and supporting a support member 107. The recess 33 has a flat bottom surface and a circular outline shape that is slightly larger than the cross-sectional shape of the support member 107. The recess 33 is formed in the center of the partition member 30.

[0036] According to the configuration in which the recess 33 for receiving the support member 107 is formed in this manner, when assembling the product, the support member 107 is placed in the recess 33, which is a predetermined fixed position, and the position of the support member 107 is less likely to vary. Therefore, it is possible to reduce variations in the acoustic characteristics of the electroacoustic transducer 2 caused by misalignment of the support member 107. The partition member 30 supports the support member 207 of the second electroacoustic conversion unit 200 at the recess 33, which is a second recess formed in the second surface 31b.

[0037] As shown in Fig. 6, the partition member 30 has a through hole 35 penetrating the partition member 30 in the thickness direction. One opening of the through hole 35 is exposed to the first space S100, and the other opening of the through hole 35 is exposed to the second space S200. This allows the first space S100 and the second space S200 to communicate with each other. One opening of the through hole 35 exposed to the first space S100 forms the sound emitting portion 100a of the first electroacoustic converter unit 100 (see Fig. 3), and the other opening exposed to the second space S200 forms the sound emitting portion 200a of the second electroacoustic converter unit 200.

[0038] Although the above description has been given of a configuration in which the partition member 30 divides the internal space of the housing 20, the partition member 30 does not necessarily have to have the function of dividing the internal space of the housing 20.

[0039] The through hole 35 is, for example, a hole that extends straight along the thickness direction of the partition member 30. When the through hole 35 has such a shape, there is an advantage that the through hole 35 can be easily formed using a mold. The contour shape of the through hole 35 is arbitrary, but the through hole 35 may have a shape that is curved like an arc, for example, as shown in FIG. 6. A plurality of through holes 35 may be formed, or only one through hole 35 may be formed.

[0040] (Electroacoustic conversion unit) Next, the electroacoustic converter units will be described. As described above, the first electroacoustic converter unit 100 and the second electroacoustic converter unit 200 have the same configuration and are arranged symmetrically across the reference plane A. Therefore, of the two electroacoustic converter units, the first electroacoustic converter unit 100 will be described below.

[0041] As shown in FIG. 3, the first electroacoustic transducer unit 100 includes a fixed pole 101, a fixed pole cover 103, a diaphragm 105, a support member 107, an insulating member 111, and a conductive member 113.

[0042] The fixed pole 101 is formed of a flat conductive material. The fixed pole 101 may have any shape and size, but may be, for example, a disk-shaped one. The fixed pole 101 has a plurality of holes formed therein to allow air to pass through.

[0043] An electret layer (not shown) is formed on the surface of the fixed electrode 101 facing the diaphragm 105. The electret layer includes a dielectric that semi-permanently holds an electric charge, and a bias voltage is applied to the conductive member of the fixed electrode 101. The first electroacoustic transducer unit 100 having the fixed electrode 101 on which the electret layer is formed does not need to apply a bias voltage to the fixed electrode 101 from outside. Note that if the fixed electrode 101 does not have an electret layer formed thereon, a bias voltage may be applied to the fixed electrode 101 via a terminal (not shown).

[0044] 7, the fixed pole 101 is connected to the ground of the sound source 6 via a wiring 5a. Note that, with respect to the second electroacoustic transducer unit 200, the fixed pole 201 is also connected to the ground of the sound source 6 via a wiring 5a.

[0045] The fixed pole cover 103 is a member for fixing the fixed pole 101, and is disposed between the fixed pole 101 and the first cover member 25. The fixed pole cover 103 is a substantially disc-shaped member with a plurality of holes formed therein, and is made of an insulating member. The plurality of holes formed in the fixed pole cover 103 are holes for allowing air to pass through. An acoustic chamber is formed by the housing 20 or the like on the rear side of the fixed pole cover 103 (i.e., the side opposite to the surface facing the diaphragm 105). In this configuration, the plurality of holes formed in the fixed pole cover 103 are one of the elements that determine the acoustic impedance, and the shape and size of the holes are used in the acoustic design of the electro-acoustic conversion unit 100.

[0046] Vibrating membrane 105 is a thin conductive film and is provided opposite fixed electrode 101. Vibrating membrane 105 is formed of, for example, a metal foil or a polymer film on which gold is vapor-deposited. Vibrating membrane 105 is, for example, circular. An annular region on the outer periphery of vibrating membrane 105 is supported by insulating member 111 and conductive member 113.

[0047] A partial region of the diaphragm 105 is pressed against the fixed pole 101 by the support member 107. Specifically, a central region of the circular diaphragm 105 is pressed against the fixed pole 101 and abuts against the central portion of the fixed pole 101. With this configuration, the distance between the diaphragm 105 and the fixed pole 101 in the thickness direction of the fixed pole 101 gradually increases as the distance from the partial region where the diaphragm 105 is in contact with the fixed pole 101 increases toward the outside (the radially outer side of the circular diaphragm 105). The outer periphery of the diaphragm 105 is the farthest from the fixed pole 101. Specifically, the diaphragm 105 and the fixed pole 101 are separated by the thickness of the insulating member 111.

[0048] Although the center of diaphragm 105 is in physical contact with fixed electrode 101, there is no electrical continuity between diaphragm 105 and fixed electrode 101. As a structure that does not establish electrical continuity between diaphragm 105 and fixed electrode 101, diaphragm 105 may be formed from an insulating film material, with no metal film formed on the surface facing fixed electrode 101, and with a metal film formed only on the surface opposite to the surface facing fixed electrode 101. With this configuration, even if the center of diaphragm 105 comes into contact with fixed electrode 101, there is no electrical continuity between diaphragm 105 and fixed electrode 101.

[0049] The support member 107 is formed of an elastic material such as a spring, a porous body, or rubber. The shape of the support member 107 is arbitrary, but is, for example, cylindrical. The support member 107 may also be cubic. The support member 107 is placed in the recess 33 of the partition member 30 and protrudes from the recess 33 by a predetermined height. The support member 107 displaces in the direction in which the diaphragm 105 displaces in response to a change in pressure within the acoustic space of the first electroacoustic conversion unit 100. A change in pressure within the acoustic space occurs, for example, when the earphone 1 is worn on or removed from the ear.

[0050] Insulating member 111 is a member that prevents conduction between vibrating membrane 105 and fixed electrode 101. Insulating member 111 is an annular member having a predetermined thickness, and is formed from, for example, resin. Insulating member 111 is disposed between vibrating membrane 105 and fixed electrode 101.

[0051] The conductive member 113 is a conductive member for applying an electric signal to the diaphragm 105. The conductive member 113 is, for example, annular and formed of a conductive sheet. The conductive member 113 is disposed on the surface of the diaphragm 105 opposite to the surface that contacts the insulating member 111, and is in contact with the outer periphery of the diaphragm 105. In other words, the conductive member 113 and the insulating member 111 sandwich the outer periphery of the diaphragm 105 therebetween. An electric signal is input to the conductive member 113 from the sound source 6 via the wiring 5b as shown in FIG. 7. The conductive member 113 may be a metal member instead of a conductive sheet. Any material may be used, for example, brass.

[0052] The first electroacoustic transducer unit 100 has been described above, and the second electroacoustic transducer unit 200 is configured in the same manner as the first electroacoustic transducer unit 100. As shown in Fig. 3, the second electroacoustic transducer unit 200 includes a fixed pole 201, a fixed pole cover 203, a diaphragm 205, a support member 207, an insulating member 211, and a conductive member 213. The fixed pole 201, the fixed pole cover 203, the diaphragm 205, the support member 207, the insulating member 211, and the conductive member 213 correspond to the fixed pole 101, the fixed pole cover 103, the diaphragm 105, the support member 107, the insulating member 111, and the conductive member 113 of the first electroacoustic transducer unit 100, respectively, and therefore a duplicated description will be omitted.

[0053] 3 and 5, the first electroacoustic converter unit 100 and the second electroacoustic converter unit 200 are arranged opposite to each other so that the sound emitting section 100a of the first electroacoustic converter unit 100 faces the sound emitting section 200a of the second electroacoustic converter unit 200. Specifically, the first electroacoustic converter unit 100 and the second electroacoustic converter unit 200 are arranged parallel to each other so that the fixed pole 101 and the fixed pole 201 are parallel to each other.

[0054] In the first electroacoustic transducer unit 100 configured as described above, the diaphragm 105 vibrates in the acoustic space of the first electroacoustic transducer unit 100 in response to a potential difference generated between the fixed electrode 101 and the diaphragm 105 based on an electrical signal input from the sound source 6. Similarly, in the second electroacoustic transducer unit 200, the diaphragm 205 vibrates in the acoustic space of the second electroacoustic transducer unit 200 in response to a potential difference generated between the fixed electrode 201 and the diaphragm 205. The sound generated in the first electroacoustic transducer unit 100 and the sound generated in the second electroacoustic transducer unit 200 are emitted from the sound emitting sections 100a and 200a, respectively. The sound generated in the first electroacoustic transducer unit 100 and the sound generated in the second electroacoustic transducer unit 200 are then emitted to the outside of the housing 20 from the sound outlet 2a on the side surface of the housing 20, and then to the outside of the earphone 1 via the conduit section 4a and the earpiece 3.

[0055] (Operation and effect of the configuration of the first embodiment) As described above, in the electroacoustic transducer 2 of this embodiment, a pair of electroacoustic transducer units, the first electroacoustic transducer unit 100 and the second electroacoustic transducer unit 200, are arranged inside the housing 20. Therefore, compared to an electroacoustic transducer provided with only one electroacoustic transducer unit, the effective area of ​​the diaphragm is doubled, improving the sensitivity of the electroacoustic transducer 2. Even when the electroacoustic transducer 2 is small and it is difficult to ensure sufficient sensitivity with one electroacoustic transducer unit, the configuration of this embodiment makes it possible to improve the sensitivity of the electroacoustic transducer 2.

[0056] In particular, in the electroacoustic transducer 2 of this embodiment, a portion of the diaphragm 105 of the first electroacoustic transducer unit 100 is pressed against the fixed pole 101, and a portion of the diaphragm 205 of the second electroacoustic transducer unit 200 is pressed against the fixed pole 201. With this configuration, in the capacitor-type drive unit, the gap between the fixed pole 101 and the diaphragm 105 and the gap between the fixed pole 201 and the diaphragm 205 are reduced, improving the sensitivity of the electroacoustic transducer 2.

[0057] In a configuration in which the diaphragm is fixed to the housing only at its outer periphery, changes inside the electroacoustic transducer cause the diaphragm to displace, resulting in stress concentration at the outer periphery of the diaphragm. In contrast, in the first electroacoustic transducer unit 100 and the second electroacoustic transducer unit 200 of this embodiment, the displacement of the diaphragm 105 and the diaphragm 205 is suppressed by the support member 107, thereby mitigating stress concentration at the outer periphery of the diaphragm 105 and the diaphragm 205. This reduces the likelihood of damage to the diaphragms 105 and 205. Furthermore, in a configuration such as this embodiment, the displacement of the diaphragm is smaller than in a configuration in which the fixed pole and the diaphragm are arranged parallel to each other. This allows the thickness of each of the first electroacoustic transducer unit 100 and the second electroacoustic transducer unit 200 to be thinner, which is advantageous for reducing the overall size of the earphone 1.

[0058] The first space S100 in which the first electroacoustic converter unit 100 is disposed and the second space S200 in which the second electroacoustic converter unit 200 is disposed may be formed as a common air chamber rather than being independent from each other. However, when the first space S100 and the second space S200 are independent from each other as in this embodiment, there is an advantage that the acoustic design of each acoustic-electroacoustic converter unit can be easily performed.

[0059] In the electroacoustic transducer 2 of this embodiment, the fixed pole 101 and the fixed pole 201 preferably have an electret layer. In a configuration in which two so-called dynamic units using magnets are arranged facing each other, the influence of magnetic repulsion occurs. However, in a configuration in which electroacoustic transducers 2 each having an electret condenser electroacoustic conversion unit are arranged facing each other as in this embodiment, factors that affect sound quality, such as repulsion, are reduced.

[0060] Fig. 8 is a cross-sectional view schematically showing a push-pull electrostatic electroacoustic transducer as a comparative example. In a push-pull electroacoustic transducer 300 as shown in Fig. 8, a pair of fixed poles 301 are arranged on both sides of a vibrating membrane 305. The push-pull electroacoustic transducer 300 requires a balanced drive amplifier (not shown) to operate the electroacoustic transducer 300. In the configuration of this embodiment, both single-ended drive and balanced drive can be used.

[0061] Furthermore, in the push-pull electroacoustic transducer 300, each fixed pole 301 constitutes an acoustic impedance, which may make it difficult to improve the sensitivity of the electroacoustic transducer 300. Furthermore, to prevent the vibrating membrane 305 from sticking to the fixed pole 301, it is necessary to make the gap between the vibrating membrane 305 and the fixed pole 301 relatively large. This configuration is disadvantageous in improving the sensitivity of the electroacoustic transducer 300 and reducing the size of the electroacoustic transducer 300. In contrast, the configuration of the electroacoustic transducer 2 of this embodiment is advantageous in improving the sensitivity of the electroacoustic transducer 2 and reducing the size of the electroacoustic transducer 2.

[0062] In the electroacoustic transducer 2 of this embodiment, the partition member 30 has a first surface 31a that defines a portion of the acoustic space of the first electroacoustic transducer unit 100 and a second surface 31b that defines a portion of the acoustic space of the second electroacoustic transducer unit 200. With this configuration, the partition member 30, which divides the interior of the housing 20 into two spaces, also serves as a member that defines the acoustic space of the first electroacoustic transducer unit 100 and the acoustic space of the second electroacoustic transducer unit 200. Therefore, compared to a configuration in which the acoustic spaces of the electroacoustic transducer units 100 and 200 are formed by members separate from the partition member 30, the number of parts is reduced and the structure is simplified. Additionally, the configuration of this embodiment, in which the partition member 30 defines a portion of the acoustic space, has the advantage of making it easy to adjust the acoustic resistance. Furthermore, the configuration of this embodiment also makes it easy to change parameters, such as acoustic mass, acoustic capacitance, and acoustic resistance, that control the vibration of the diaphragm 105.

[0063] In the electroacoustic transducer 2 of this embodiment, recesses 33 for receiving and supporting the support member 107 are formed on each of the first surface 31a and the second surface 31b of the partition member 30. With this configuration, the support member 107 is disposed in the recesses 33, and the position of the support member 107 is less likely to shift. Therefore, variations in acoustic characteristics caused by shifts in the position of the support member 107 are reduced.

[0064] In the electroacoustic transducer 2 of this embodiment, the partition member 30 is a plate-like member, and a through hole 35 is formed in the partition member 30, one opening of which is exposed to the first space S100 and the other opening of which is exposed to the second space S200. With this configuration, the acoustic space of the first electroacoustic conversion unit 100 and the acoustic space of the second electroacoustic conversion unit 200 can be communicated with each other using the simple structure in which the through hole 35 is formed in the partition member 30, which is a plate-like member.

[0065] In the electro-acoustic transducer 2 of this embodiment, the sound outlet 2a that releases sound from the housing 20 to the outside is formed on the side surface of the housing 20, rather than on the first cover member 25 and second cover member 26 of the housing 20. With this configuration, the design of the earphone 1 can be adapted to the shape of the user's ear and its surroundings, compared to a configuration in which the sound outlet is provided on the first cover member 25 and second cover member 26. This makes the earphone 1 easier to use for users.

[0066] In the electroacoustic transducer 2 of this embodiment, the housing 20 has a cylindrical housing member 21, and a first cover member 25 is attached to one end of the housing member 21, and a second cover member 26 is attached to the other end of the housing member 21. According to this configuration, when assembling a product, a worker places the first electroacoustic conversion unit 100 inside the housing 20 from one end side of the housing 20, and attaches the first cover member 25. Thereafter, a worker places the second electroacoustic conversion unit 200 inside the housing 20 from the other end side of the housing 20, and attaches the second cover member 26. With this procedure, a worker can easily assemble the electroacoustic transducer 2.

[0067] (Second embodiment) In the first embodiment, a configuration in which the first electroacoustic converter unit 100 and the second electroacoustic converter unit 200 are arranged in parallel has been exemplified, but the first electroacoustic converter unit 100 and the second electroacoustic converter unit 200 may also be arranged as shown in Fig. 9. Fig. 9 is a cross-sectional view showing the configuration of an electroacoustic transducer of the second embodiment. Fig. 10 is a perspective view showing a state in which an earphone having an electroacoustic transducer of the second embodiment is worn by a user.

[0068] 9 includes a housing 20A, a partition member 30A, a first electroacoustic transducer unit 100, and a second electroacoustic transducer unit 200. The housing 20A includes a housing member 21A having a shape different from that of the housing member 21 of the first embodiment, a first cover member 25 attached to one end of the housing member 21A, and a second cover member 26 attached to the other end of the housing member 21A.

[0069] The partition member 30A is formed in a shape such that the thickness gradually decreases from the end of the housing 20A on the side where the sound outlet 2a is located (the end on the left side in FIG. 9), which is the side closer to the earpiece 3, to the end opposite the sound outlet 2a (the end on the right side in the figure). Accordingly, the housing 20A is formed so that the thickness of the housing 20A at the end opposite the sound outlet 2a is thinner than the thickness at the end on the sound outlet 2a side.

[0070] As in the first embodiment, the first electroacoustic transducer unit 100 and the second electroacoustic transducer unit 200 are arranged symmetrically across the reference plane A and facing each other. Specifically, the first electroacoustic transducer unit 100 and the second electroacoustic transducer unit 200 are arranged at an angle so that the distance between them gradually decreases from the end on the side where the sound outlet 2a is located to the opposite end. The other configuration of the electroacoustic transducer 2A is the same as in the first embodiment, so a duplicated description will be omitted.

[0071] According to the configuration of the second embodiment, compared to a configuration in which the first electroacoustic transducer unit 100 and the second electroacoustic transducer unit 200 are arranged in parallel, the housing 20A is formed thinner in a region of the housing 20A that is particularly close to the helix 7 of the user's auricle (see FIG. 10 ), that is, on the opposite side to the side where the sound outlet 2a is located. Therefore, the electroacoustic transducer 2A of the second embodiment can avoid interference between the housing 20A and the ear, and the wearing comfort of the earphone 1 is also improved.

[0072] As in the first embodiment, the electroacoustic transducer 2A of the second embodiment has a first electroacoustic transducer unit 100 and a second electroacoustic transducer unit 200 arranged opposite each other within the housing 20A, thereby achieving the effect of improving the sensitivity of the electroacoustic transducer 2A.

[0073] The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by functionally or physically distributing or integrating any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of the new embodiments resulting from the combination also have the effects of the original embodiments. [Explanation of symbols]

[0074] 1 earphones 2. Electroacoustic transducer 2a sound outlet 3 earpieces 4. Conduit forming member 4a Conduit section 4b Cable connection 4c conduit 5 Cable 5a wiring 5b Wiring 6. Sound Source 7 Earrings 20 Case 21 Housing member 25 first cover member 25a flat surface 25b side 26 Second cover member 26a flat surface 26b Side 30 Partition member 30-1 Thick part 30-2 Circular section 31a First Side 31b Second Face 33 Recess 35 through holes 100 First electroacoustic conversion unit 100a Sound emitting part 101 Fixed pole 103 Fixed pole cover 105 Vibrating membrane 107 Support member 111 Insulating materials 113 Conductive materials 200 Second electroacoustic conversion unit 200a Sound emitting part 201 Fixed pole 203 Fixed pole cover 205 Vibrating membrane 207 Support member 211 Insulating materials 213 Conductive materials A Reference plane CL center axis S100 First Space S200 Second Space

Claims

1. a housing having a sound outlet for emitting sound to the outside; a partition member disposed inside the housing; a first electroacoustic transducer unit disposed inside the housing; a second electroacoustic transducer unit disposed inside the housing; Equipped with The first electroacoustic transducer unit and the second electroacoustic transducer unit are A fixed pole and a vibrating membrane disposed opposite the fixed electrode and vibrating in response to a potential difference generated between the vibrating membrane and the fixed electrode based on an electric signal; a support member that supports a partial area of ​​the vibration membrane and brings the part of the vibration membrane into contact with the fixed pole, The distance between the vibration membrane and the fixed pole is set to increase as the distance from the partial region to the outside increases, the sound emitting portion of the first electroacoustic transducer unit and the sound emitting portion of the second electroacoustic transducer unit are arranged opposite to each other with the partition member interposed therebetween so as to communicate with the sound outlet, the partition member supports the support member of the first electroacoustic transducer unit and the support member of the second electroacoustic transducer unit. Electroacoustic transducer.

2. The partition member is a first recess formed on a first surface that defines a part of the acoustic space of the first electroacoustic transducer unit, the first recess receiving the support member of the first electroacoustic transducer unit and supporting the support member; a second recess formed on a second surface that defines a part of the acoustic space of the second electroacoustic transducer unit, the second recess receiving the support member of the second electroacoustic transducer unit and supporting the support member; 2. The electroacoustic transducer according to claim 1.

3. The partition member is provided to divide the interior of the housing into a first space and a second space.

3. The electroacoustic transducer according to claim 1 or 2.

4. the partition member is a plate-like member having a through hole formed therein, one opening of which is exposed to the first space and the other opening of which is exposed to the second space; 4. The electroacoustic transducer according to claim 3.

5. The housing is cylindrical, The sound outlet is formed in a side surface of the housing. The electroacoustic transducer according to any one of claims 1 to 4.

6. The first electroacoustic transducer unit and the second electroacoustic transducer unit are In a cross section cut in the thickness direction of the housing, the sound outlets are arranged at an angle such that the distance between them gradually decreases from the end of the housing on the side where the sound outlet is located to the end opposite to the sound outlet.

6. The electroacoustic transducer according to claim 5.

7. The housing includes: a cylindrical housing member; a first cover member attached to one end of the housing member; a second cover member attached to the other end of the housing member; having The electro-acoustic transducer according to any one of claims 1 to 6.

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