Micro speaker and earphone

Abstract

To provide a micro speaker and earphone capable of reducing a thickness compared with a conventional configuration while suppressing sound quality adjustment and sound quality variation.SOLUTION: A micro speaker includes: a bottomed cylindrical frame incorporated in a housing of an earphone; a diaphragm arranged in an opening part of the frame and having an edge in a peripheral edge of a dome; a cylindrical voice coil co-axially fixed to the diaphragm; and a ring-shaped magnet arranged inside the frame and having an under-dome ventilation path at the center, coaxial with the voice coil. The frame comprises: a first vacant room formed on the opposite side of the diaphragm by sandwiching the magnet; a second vacant room formed in a ring shape on an outer side of the magnet; an under-edge ventilation path including one end part opening to face the edge and the other end part arranged on the opposite side of the one end part and communicating with the first vacant room; a first ventilation channel for allowing the first vacant room to communicate with the second vacant room; and a second ventilation channel for allowing the second vacant room to be open to an outer side of the frame.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a micro-speaker and an earphone. [Background technology]

[0002] A speaker unit and earphones that adjust sound quality and suppress variation in sound quality have been proposed (see, for example, Patent Document 1). This speaker unit is incorporated into the housing of the earphone, and includes a cylindrical frame, a diaphragm that emits sound, and a substrate to which the wiring of the coil provided on the diaphragm is connected. A space is formed inside the frame, and the diaphragm and the substrate are arranged inside the frame with the space between them. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-91463 A Summary of the Invention [Problem to be solved by the invention]

[0004] The speaker unit and earphones disclosed in Patent Document 1 have a structure in which the diaphragm and the substrate are arranged with a space between them. By providing this space, the sound quality is adjusted and the variation in sound quality is suppressed. However, this arrangement has a problem in that the distance between the diaphragm and the substrate (in other words, the thickness of the speaker unit) becomes thick depending on the size of the space. In other words, by arranging the diaphragm and the substrate with a space between them, it is difficult to miniaturize the speaker unit.

[0005] The present disclosure has been devised in consideration of the above-mentioned conventional circumstances, and aims to provide a micro-speaker and earphones equipped with such a micro-speaker that can adjust sound quality and suppress variation in sound quality while making the housing thinner than conventional configurations. [Means for solving the problem]

[0006] The present disclosure provides a microspeaker to be incorporated into the housing of an earphone, the microspeaker comprising: a cylindrical frame with a bottom; a diaphragm provided at an opening of the frame and having an edge on the periphery of a dome; a cylindrical voice coil coaxially fixed to the diaphragm; and a ring-shaped magnet disposed within the frame and having an under-dome air passage at its center that is coaxial with the voice coil, the frame having a first chamber formed on the opposite side of the diaphragm across the magnet, a second chamber formed in a ring shape outside the magnet, an under-edge air passage having one end that opens facing the edge and the other end that is provided opposite the one end and leads to the first chamber, a first air passage connecting the first chamber to the second chamber, and a second air passage that opens the second chamber to the outside of the frame.

[0007] The present disclosure provides a microspeaker to be incorporated into the housing of an earphone, the microspeaker comprising: a cylindrical frame with a bottom; a diaphragm provided at an opening of the frame and having an edge on the periphery of a dome; a cylindrical voice coil coaxially fixed to the diaphragm; and an annular magnet disposed within the frame and having an under-dome air passage at its center that is coaxial with the voice coil, the frame having a third chamber formed on the opposite side of the diaphragm across the magnet; a fourth chamber formed in an annular shape outside the magnet; an under-edge air passage having one end that opens facing the edge, another end that is provided opposite to the one end and leads to the third chamber, and an intermediate portion that is provided between the one end and the other end and leads to the second chamber; a protrusion that extends radially outward from a part of the outer periphery and has a fifth chamber; a third air passage that connects the third chamber to the fifth chamber; and a fourth air passage that opens the fifth chamber to the outside of the frame.

[0008] The present disclosure provides an earphone including a micro-speaker. Effect of the Invention

[0009] According to the microspeaker of the present disclosure, it is possible to adjust the sound quality and suppress variation in sound quality while making the thickness thinner than that of conventional configurations.

[0010] According to the earphone of the present disclosure, the amount of protrusion to the outside from the ear canal into which it is inserted can be kept small compared to conventional configurations. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a side view showing a part of an earphone equipped with a microspeaker according to a first embodiment; [Diagram 2] A perspective view of the microspeaker shown in FIG. 1, seen obliquely from above. [Diagram 3] A bottom perspective view of the microspeaker shown in Figure 2, turned upside down. [Figure 4] Bottom view of the microspeaker shown in Figure 3 [Diagram 5] Cross section AA of Figure 4 [Figure 6] Cross section B-B of Figure 4 [Figure 7] Operation diagram showing air flow [Figure 8] 1 is a cross-sectional view of a micro speaker according to a comparative example; [Figure 9] FIG. 11 is a side view showing a part of an earphone equipped with a microspeaker according to a second embodiment. [Figure 10] FIG. 10 is a perspective view of the microspeaker shown in FIG. 9, seen obliquely from above. [Figure 11] A bottom perspective view of the microspeaker shown in Figure 10, turned upside down. [Figure 12] Bottom view of the microspeaker shown in Figure 11 [Figure 13] Cross-sectional view of Fig. 12 [Figure 14] EE cross section of Figure 12 [Figure 15] An explanatory diagram showing the air flow in the DD cross section of Figure 12. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, with reference to the drawings as appropriate, an embodiment specifically disclosing a microspeaker and an earphone according to the present disclosure will be described in detail. However, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters or duplicate description of substantially the same configuration may be omitted. This is to avoid the following description becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. Note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0013] In the following description, the reference numerals appearing in the accompanying drawings are given as references to explain the configuration of the micro-speaker or earphone, and the same reference numerals in the accompanying drawings indicate the same configuration.

[0014] [Embodiment 1] 1 is a partially cutaway side view of earphone 13 equipped with microspeaker 11 according to embodiment 1. Earphone 13 has a housing 15, microspeaker 11, a substrate 17, and a battery 19.

[0015] The inside of the housing 15 of the earphone 13 forms an accommodation space 21 that accommodates the microspeaker 11, the substrate 17, and the battery 19. The housing 15 has a sound conduit 25 with a sound emission hole 23. In the earphone 13, an earpiece (not shown) is attached to the outer periphery of the sound conduit 25. The earpiece is prevented from coming off by a locking claw 27 of the sound conduit 25. The sound conduit 25 with the earpiece attached is inserted into the wearer's ear. That is, in the earphone 13, sound that has passed through the sound conduit 25 from the microspeaker 11 is emitted from the sound emission hole 23 upward (for example, toward the inside of the wearer's ear).

[0016] In this specification, unless otherwise specified, the upper side refers to the direction in which sound that has passed through the sound guide tube 25 is emitted from the sound emission hole 23, and the lower side refers to the side in which the battery 19 is housed relative to the microspeaker 11.

[0017] The substrate 17 is electrically connected to the battery 19 by a flexible flat cable 29. The microspeaker 11 is electrically connected to the substrate 17 by a flat cable 31. Various types of power (power supply), audio signals, and control signals are transmitted to the microspeaker 11 from the substrate 17 via the flat cable 31.

[0018] Fig. 2 is a perspective view of the microspeaker 11 shown in Fig. 1, seen obliquely from above. The microspeaker 11 is formed in a flat, generally cylindrical shape. The microspeaker 11 has a frame 33 that is tubular with a bottom. The frame 33 is formed, for example, by injection molding using a resin material. A diaphragm 35 is provided in an opening formed on the upper side of the frame 33. The diaphragm 35 has a dome 37 that is disposed so as to occupy the central portion of the housing of the microspeaker 11, and an edge 39 that is formed in a generally circular plate shape around the periphery of the dome 37.

[0019] The bottom of frame 33 which is in the shape of a bottomed cylinder may be integral with frame 33, or a separate member may be fixed integrally with frame 33. In the first embodiment, a separate rear box 41 is fixed integrally to frame 33 at the bottom of frame 33. Diaphragm 35, frame 33, and rear box 41, each of which is circular, are joined coaxially.

[0020] Fig. 3 is a bottom perspective view of the microspeaker 11 shown in Fig. 2 turned upside down. A pair of second ventilation paths 43, which will be described later, are opened at both diametrical ends of the bottom surface of the rear box 41. Each of these second ventilation paths 43 is covered with a second mesh material 45, which will be described later.

[0021] 4 is a bottom view of the microspeaker 11 shown in FIG. 3. The rear box 41 has a circular bottom central portion 47, and the periphery of the bottom central portion 47 is an annular hollowed-out portion 49 that is thinner than the bottom central portion 47. In other words, there is a step between the bottom central portion 47 and the hollowed-out portion 49 (see FIG. 3). The second ventilation path 43 and the second mesh material 45 are disposed in this hollowed-out portion 49. On the outer periphery of the bottom central portion 47, four protrusions 51 are formed at equal intervals in the circumferential direction so as to protrude into the hollowed-out portion 49. These protrusions 51 are portions within the frame 33 where ventilation paths, which will be described later, are formed.

[0022] Fig. 5 is a cross-sectional view taken along line AA in Fig. 4. Diaphragm 35 has a ring 53 provided on the outer periphery of edge 39. Diaphragm 35 is supported by frame 33 via edge 39 by fixing ring 53 to an opening of frame 33. Diaphragm 35 has a dome 37 with a lower surface that is a concave curved surface.

[0023] The diaphragm 35 has an edge 39 that is processed to be more flexible than the dome 37. The edge 39 has a plurality of oblique embossments that reduce the strength of the periphery, making it easier to vibrate the diaphragm 35. The edge 39 makes it easier for the diaphragm 35 to vibrate, and when no audio signal is input to the voice coil 55, the edge 39 maintains the diaphragm 35 in a neutral position. The diaphragm 35 has a cylindrical voice coil 55 coaxially fixed to the lower surface (concave curved surface) of the dome 37.

[0024] The voice coil 55 is formed by winding a metallic wire multiple times into a ring (cylindrical shape). The voice coil 55 is connected to an input terminal (not shown) to which an audio signal is input from the substrate 17. The upper end of the voice coil 55 is fixed to the diaphragm 35, and the lower end is inserted into a magnetic gap in the magnetic circuit of the magnet 57. The diaphragm 35 vibrates due to the vibration of the fixed voice coil 55, and converts the audio signal input to the voice coil 55 into sound.

[0025] Within the frame 33, an annular magnet 57 is disposed coaxially with the voice coil 55 inside the voice coil 55. The magnet 57 has an under-dome air passage 59 at its center, which is coaxial with the voice coil 55. The magnet 57 is fixed coaxially to the inside of a cylindrical yoke 61 with a bottom that is fixed within the frame 33.

[0026] The yoke 61 is made of a magnetic material. A circular ring-shaped plate 63 is coaxially fixed to the upper surface of the magnet 57. The plate 63 is made of a magnetic material. A flange-shaped stopper 65 is fixed to the upper surface of the plate 63. The upper surface of the stopper 65 has a convex curved surface following the concave curved surface of the dome 37. The stopper 65 restricts the displacement of the diaphragm 35 toward the magnet 57, and restricts the diaphragm 35 from coming too close to the plate 63.

[0027] The yoke 61, the magnet 57, and the plate 63 form a magnetic circuit of the microspeaker 11. The magnetic circuit is a circuit that generates a steady magnetic flux in a magnetic gap. The yoke 61 forms a magnetic gap between its inner peripheral surface and the outer peripheral surface of the plate 63. The lower end of the cylindrical voice coil 55 is inserted into this magnetic gap.

[0028] A magnetic fluid 67 is disposed in the magnetic gap. The magnetic fluid 67 is disposed in a ring shape between the outer periphery of the plate 63 and the inner periphery of the voice coil 55. The gap between the voice coil 55 and the plate 63 is sealed by the magnetic fluid 67. The magnetic fluid 67 is a magnetic colloidal solution in which ferromagnetic particles, a dispersant that covers the surfaces of the ferromagnetic particles, and a solvent are mixed. By disposing the magnetic fluid 67 between the voice coil 55 and the plate 63, the microspeaker 11 can stabilize the vibration of the voice coil 55 with low friction resistance.

[0029] The driver section of the microspeaker 11, in which the yoke 61, the magnet 57, the plate 63 and the stopper 65 are coaxially fixed, has an under-dome air passage 59 formed penetrating through the center.

[0030] On the other hand, the frame 33 is configured to have a first chamber 69, a second chamber 71, an under-edge ventilation passage 73, a first ventilation passage 75, and a second ventilation passage 43.

[0031] The frame 33 is formed in a cylindrical shape with a bottom, and an opening on the opposite side to the diaphragm 35 is blocked by the rear box 41. The first chamber 69 is formed between the rear box 41 and the yoke 61, which is a cylindrical shape with a bottom and is fixed inside the frame 33. That is, the first chamber 69 is formed on the opposite side to the diaphragm 35 with the magnet 57 in between. The first chamber 69 is a cylindrical space sandwiched between the bottom of the yoke 61 and the bottom wall of the rear box 41. The first chamber 69 is disposed coaxially with the under-dome air passage 59. The lower end of the under-dome air passage 59 is physically connected to the first chamber 69.

[0032] The second chamber 71 is formed in an annular shape on the side wall of the frame 33 outside the magnet 57. The second chamber 71 is a cylindrical space having a predetermined thickness and is coaxial with the magnet 57. The upper part of the second chamber 71 is closed by the upper wall of the frame 33, and the lower part of the second chamber 71 is closed by annular partition wall 77 of the rear box 41.

[0033] One end of the under-edge air passage 73 opens facing the edge 39. The other end of the under-edge air passage 73 communicates with the first chamber 69. The under-edge air passage 73 is surrounded by a vertical wall portion 79 in the second chamber 71, and is therefore separated from the second chamber 71 without being directly connected thereto. In other words, the under-edge air passage 73 is disposed in the second chamber 71 in the shape of a pipe shaft.

[0034] Fig. 6 is a cross-sectional view taken along line BB of Fig. 4. The first ventilation passage 75 is formed by eroding a portion of the annular partition wall 77 at the protrusion 51 of the rear box 41. The first ventilation passage 75 connects the first chamber 69 to the second chamber 71. The first ventilation passage 75 is provided at two locations on both sides in the diameter direction of the rear box 41. The air in the first chamber 69 and the air in the second chamber 71 can move through the first ventilation passage 75.

[0035] Further, the annular partition wall 77 is formed with a second ventilation passage 43 that opens the second chamber 71 to the outside of the frame 33 at the CC cross section position shown in Fig. 4. The second ventilation passage 43 penetrates the annular partition wall 77 and opens at the hollowed-out portion 49. As shown in Fig. 4, the second ventilation passage 43 is provided at two locations on both sides in the diameter direction of the rear box 41. The air in the second chamber 71 and the air outside the frame can move through the second ventilation passage 43.

[0036] Thus, in the microspeaker 11, the first air passage 75 and the second air passage 43 are disposed at different positions in the circumferential direction of the frame 33.

[0037] In the microspeaker 11, the first air passage 75 and the second air passage 43 have mesh materials that determine the air resistance. A first mesh material 81 shown in Fig. 6 is attached to the first air passage 75. A second mesh material 45 shown in Figs. 3 and 4 is attached to the second air passage 43. The first mesh material 81 and the second mesh material 45 control the resistance of air passing through the first air passage 75 and the second air passage 43. The first mesh material 81 and the second mesh material 45 may be, for example, a nonwoven fabric or a porous plate-like member made of chemical fiber.

[0038] FIG. 7 is an explanatory diagram showing the operation of air flow. The upper diagram of FIG. 7 is a cross-sectional view taken along line AA in FIG. 4, the middle diagram is a cross-sectional view taken along line BB in FIG. 4, and the lower diagram is a cross-sectional view taken along line CC in FIG. 4. As shown in the upper diagram of FIG. 7, in the microspeaker 11, when the voice coil 55 is driven to vibrate the diaphragm 35, the air under the dome 37 moves to the under-dome air passage 59 due to the displacement. The air in the under-dome air passage 59 is pushed by the movement of the air under the dome 37, and part or all of it moves to the first chamber 69. Similarly, the air under the edge 39 also moves to the under-edge air passage 73. The air in the under-edge air passage 73 is pushed by the movement of the air under the edge 39, and part or all of it moves to the first chamber 69.

[0039] As shown in the middle diagram of Figure 7, some or all of the air in the first chamber 69 moves through the first air passage 75 to the second chamber 71 as air moves from the under-dome air passage 59 and the under-edge air passage 73.

[0040] 7, the air in the second chamber 71 is pushed by the air moving from the first chamber 69, and some or all of the air moves through the second air passage 43 to the outside of the frame 33. If the diaphragm 35 is displaced in the opposite direction, air moves from the outside of the frame 33 to the second chamber 71 through the second air passage 43, and then the air flows in the opposite direction and moves into the gap below the diaphragm.

[0041] Next, the operation of the above-mentioned first embodiment will be described.

[0042] The microspeaker 11 of embodiment 1 is incorporated into the housing 15 of the earphone 13, and comprises a cylindrical frame 33 with a bottom, a diaphragm 35 provided at the opening of the frame 33 and having an edge 39 on the periphery of a dome 37, a cylindrical voice coil 55 fixed coaxially to the diaphragm 35, and an annular magnet 57 disposed within the frame 33 and having an under-dome air passage 59 at its center which is coaxial with the voice coil 55. The frame 33 is equipped with a first chamber 69 formed on the opposite side of the diaphragm 35 across the magnet 57, a second chamber 71 formed in a ring shape outside the magnet 57, an under-edge air passage 73 having one end opening facing the edge 39 and the other end located opposite the one end and communicating with the first chamber 69, a first air passage 75 connecting the first chamber 69 to the second chamber 71, and a second air passage 43 opening the second chamber 71 to the outside of the frame.

[0043] In the microspeaker 11 according to the first embodiment, the frame 33 is formed in a cylindrical shape with a bottom. In the cylindrical shape with a bottom, one of both ends in the axial direction of the cylinder is a bottom that is closed, and the other is an opening that opens the inside of the cylinder. The bottom of the frame 33 may be integral with the frame 33, or a separate member may be fixed integrally with the frame 33.

[0044] A circular diaphragm 35 is provided on the opening side of the frame 33. The diaphragm 35 has an edge 39 on the periphery of a dome 37. The edge 39 is a soft edge with multiple oblique embossed portions, and as the edge 39 flexes, the dome 37 and the edge 39 vibrate smoothly as one unit.

[0045] The dome 37 has a concave curved surface on the opening side of the frame 33. A cylindrical voice coil 55 is coaxially fixed to the surface on the opening side of the diaphragm 35. A portion of the voice coil 55 enters the cylindrical interior of the frame 33 from the opening.

[0046] A magnet 57 is provided inside the frame 33 and spaced apart from the diaphragm 35, inside the voice coil 55. The magnet 57 is arranged coaxially with the voice coil 55. The magnet 57 is formed in an annular shape, and has an under-dome air passage 59 that passes through the center coaxially. This allows air under the dome between the diaphragm 35 and the magnet 57 to move through the under-dome air passage 59 in a direction along the axis of the frame 33.

[0047] 8 is a cross-sectional view of a microspeaker 83 according to a comparative example. Here, the frame structure of the microspeaker 83 according to the comparative example will be described. A frame 85 of the microspeaker 83 is provided with a driver bottom cover 87 spaced below the yoke 61. A first cavity 69 is formed between the yoke 61 and the driver bottom cover 87. An under-edge air passage 73 is formed in the frame 85, and the under-edge air passage 73 communicates with the first cavity 69. A first air passage 89 is formed in the driver bottom cover 87, which is coaxial with the under-dome air passage 59. The first air passage 89 is covered with a first mesh material 81.

[0048] A second chamber 93 is formed between the driver bottom cover 87 and the rear box 91. A second air passage 95 that opens the second chamber 93 to the outside of the frame is formed in the rear box 91 coaxially with the under-dome air passage 59. The second air passage 95 is covered with a second mesh material 45. In the microspeaker 83 according to this comparative example, the under-dome air passage 59, the first chamber 69, and the second chamber 93 are arranged in series one above the other. For this reason, when a chamber of a predetermined volume is secured, there is a limit to how low the overall height of the frame 85 can be reduced.

[0049] Meanwhile, in the microspeaker 11 according to the first embodiment, a first chamber 69 is formed in the frame 33 on the opposite side of the diaphragm 35 across the magnet 57. That is, the under-dome air passage 59 connects the gap under the dome with the first chamber 69. Therefore, the air in the gap under the dome, the under-dome air passage 59, and the first chamber 69 moves in accordance with the displacement of the diaphragm 35 which vibrates when driven by the voice coil 55.

[0050] In the frame 33, an annular second chamber 71 is formed which is coaxial with the voice coil 55 and is located between the diaphragm 35 and the first chamber 69. The second chamber 71 is formed to be located outside the voice coil 55. The second chamber 71 has a lower end side in the axial direction which overlaps with the first chamber 69 and protrudes outward beyond the first chamber 69.

[0051] That is, the microspeaker 11 is arranged such that the under-dome air passage 59 is at the center, and the magnet 57, the voice coil 55, and the second chamber 71 are arranged coaxially in this order on the radially outer side of the under-dome air passage 59. The diaphragm 35 is arranged on one side of the axial direction of the frame 33 which is the center of all of these, and the first chamber 69 is arranged on the other side of the axial direction.

[0052] Further, an under-edge air passage 73 is formed in the frame 33, one end of which opens facing the edge 39 and the other end of which communicates with the first chamber 69. The under-edge air passage 73 is formed by partitioning a part of the second chamber 71. In other words, the second chamber 71 contains the under-edge air passage 73. The air in the under-edge air passage 73 does not move directly to the second chamber 71, but first moves to the first chamber 69, thereby moving the air in the first chamber 69 to the second chamber 71.

[0053] In the microspeaker 11, the frame 33 has a first air passage 75 that connects the first chamber 69 to the second chamber 71. The frame 33 also has a second air passage 43 that opens the second chamber 71 to the outside of the frame.

[0054] Therefore, in the microspeaker 11, when the voice coil 55 is driven, the diaphragm 35 vibrates, and the displacement of the air in the gap under the diaphragm causes the air in the under-dome air passage 59 and the under-edge air passage 73 to move. Accordingly, the air in the under-dome air passage 59 moves the air in the first chamber 69. Similarly, the air in the under-edge air passage 73 also moves the air in the first chamber 69. In other words, both the air in the under-dome air passage 59 and the air in the under-edge air passage 73 actuate the air in the first chamber 69.

[0055] The air that has moved to the first chamber 69 passes through the first air passage 75 and moves the air in the first chamber 69 to the second chamber 71 that is annular outside the magnet 57. When the air moves from the first air passage 75 to the second chamber 71, the air inside is pushed, and a part of the air moves to the outside of the frame through the second air passage 43. If the diaphragm 35 is displaced in the opposite direction, air from outside the frame moves to the second chamber 71 through the second air passage 43, and the air then moves to the gap below the diaphragm by the reverse flow.

[0056] Thus, in the microspeaker 11, the volume within the frame through which air moves due to the displacement of the diaphragm 35 is composed of the under-dome air passage 59, the first chamber 69, the second chamber 71, and the under-edge air passage 73. These volumes are set to a size that allows the desired sound quality to be ensured. The first chamber 69 is formed as a flat space perpendicular to the axis of the frame 33 on the opposite side of the diaphragm 35 with the magnet 57 in between. On the other hand, the second chamber 71 communicating with the first chamber 69 is formed in a ring shape outside the magnet 57 between the diaphragm 35 and the first chamber 69. That is, the thickness in the direction along the axis of the frame 33 is suppressed.

[0057] That is, in the microspeaker 11, a predetermined volume of empty space is secured mainly by the first empty space 69 and the second empty space 71 to adjust the sound quality and suppress variation in sound quality, while the second empty space 71 is arranged in an annular shape outside the magnet 57, thereby removing that volume from the serial arrangement of the under-dome air passage 59 and the first empty space 69. As a result, the microspeaker 11 can be made thinner than the conventional configuration, without depending on the thickness of the second empty space 71.

[0058] Furthermore, in the microspeaker 11, the first ventilation path 75 and the second ventilation path 43 are disposed at different positions in the circumferential direction of the frame 33.

[0059] In this microspeaker 11, a first air passage 75 that connects the first chamber 69 to the second chamber 71 and a second air passage 43 that opens the second chamber 71 to the outside of the frame are arranged at different positions in the circumferential direction of the frame 33. The second chamber 71 is formed in an annular shape within the frame between the diaphragm 35 and the first chamber 69. The first chamber 69 is formed as a disk-shaped space at the bottom of the frame 33.

[0060] The annular second chamber 71 is partitioned from the disk-shaped first chamber 69 by an annular partition wall 77. The inner peripheral edge of the annular second chamber 71 overlaps with the first chamber 69. The annular partition wall 77 is formed so that its outer peripheral side is larger than the outer diameter of the first chamber 69 and extends radially outward from the first chamber 69. In other words, the annular partition wall 77 that separates the second chamber 71 and the first chamber 69 has its inner peripheral side overlapping with the first chamber 69 and its outer peripheral side protruding outside the frame.

[0061] As a result, in the second chamber 71, a first air passage 75 communicating with the first chamber 69 can be formed on the inner peripheral side of the annular partition wall 77, and a second air passage 43 communicating with the outside of the frame can be formed on the outer peripheral side of the annular partition wall 77. As a result, by arranging the first air passage 75 and the second air passage 43 in the annular partition wall 77 at different circumferential positions in the second chamber 71, the frame 33 can be prevented from becoming enlarged in the radial direction, and can communicate the second chamber 71 with both the first chamber 69 and the outside of the frame with a compact structure.

[0062] Furthermore, in the microspeaker 11, the first air passage 75 and the second air passage 43 have a mesh material that determines the air resistance.

[0063] In this microspeaker 11, the first air passage 75 and the second air passage 43 have a mesh material that determines the air resistance. The mesh material can obtain a desired air resistance by changing the mesh size of the mesh material. The microspeaker 11 can change to a desired sound pressure frequency characteristic (in other words, obtain a desired sound pressure frequency characteristic) by changing the air resistance of at least one of the first air passage 75 and the second air passage 43. That is, the sound pressure frequency characteristic that determines the quality of the sound emitted from the diaphragm 35 can be controlled by the volumes of the first chamber 69 and the second chamber 71 and the air resistance, which is a characteristic of the mesh material.

[0064] Moreover, the earphone 13 according to the first embodiment includes a micro speaker 11.

[0065] Earphone 13 according to the first embodiment houses microspeaker 11 in its housing 15. Microspeaker 11 can be thinner than conventional configurations while adjusting the sound quality and suppressing variation in sound quality, so the dimension in the thickness direction of housing 15 can be reduced accordingly. As a result, earphone 13 can keep the amount of protrusion to the outside from the ear canal into which it is inserted smaller than conventional configurations.

[0066] Therefore, the microspeaker 11 according to the first embodiment can be thinner than the conventional configuration while adjusting the sound quality and suppressing the variation in the sound quality. Also, the earphone 13 according to the first embodiment can reduce the amount of protrusion to the outside from the ear canal into which it is inserted, compared to the conventional configuration.

[0067] [Embodiment 2] Next, a second embodiment will be described. 9 is a partially cutaway side view of an earphone 99 equipped with a microspeaker 97 according to embodiment 2. In embodiment 2, the same members as those shown in embodiment 1 are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0068] In some cases, the housing 15 of the earphones 99 is formed asymmetrically with respect to the axis of the sound conduit 25. In this case, surplus space 101 is generated in the housing space 21 immediately below the sound conduit 25. In the earphones 99, this surplus space 101 is utilized to position a protrusion 103 that extends from the frame.

[0069] FIG. 10 is a perspective view of the microspeaker 97 shown in FIG. 9, seen from diagonally above. The main body of the frame 105 is formed in a cylindrical shape. The frame 105 has a protruding portion 103 protruding radially outward from a portion of the outer periphery of the main body. The frame 105 has a ring-shaped cover 107 attached to the upper surface of the main body, which covers the outer periphery of the diaphragm 35. The cover 107 exposes the dome 37 excluding the inner and outer periphery of the entire diaphragm, and up to about half the diameter of the edge 39. A rear box 109 having substantially the same outer shape as the frame 105 in a plan view and a substrate 111 are integrally laminated on the lower surface side of the frame 105. A fourth ventilation path 113 opens at the protruding tip surface of the protruding portion 103. The opening of the fourth ventilation path 113 is covered by a second mesh material 115.

[0070] Fig. 11 is a bottom perspective view of the microspeaker 97 shown in Fig. 10 turned upside down. Frame 105 has a bottom opening 117 (see Fig. 13) on its bottom surface. This bottom opening 117 is closed by rear box 109 stacked on its bottom surface. Rear box 109 has a concave opening 119 (see Fig. 13) on its bottom surface. Concave opening 119 of rear box 109 is closed by substrate 111 stacked on its bottom surface.

[0071] Fig. 12 is a bottom view of the microspeaker 97 shown in Fig. 11. The rear box 109 is provided with a plurality of positioning ribs 121 for regulating the fixing position of the substrate 111 outside the area where the substrate 111 is fixed.

[0072] Fig. 13 is a DD cross-sectional view of Fig. 12. Microspeaker 97 differs from microspeaker 11 of embodiment 1 in that fourth chamber 123 (see Fig. 14) communicates with third chamber 127 via under-edge air passage 125, and in that frame 105 has protruding portion 103 extending radially outward, and protruding portion 103 has fifth chamber 129. As other configurations are the same as microspeaker 11 of embodiment 1, the following description will focus on the differences.

[0073] The frame 105 has a third chamber 127 formed on the opposite side of the diaphragm 35 with the magnet 57 in between. The third chamber 127 is formed between the concave opening 119 of the rear box 109 and the substrate 111. The frame 105 has a pair of under-edge air passages 125 formed on both sides in the diameter direction inside the cylinder. The under-edge air passage 125 has one end that opens facing the edge 39 and the other end that is provided opposite the one end and leads to the third chamber 127. The under-edge air passage 125 also has a middle part in the up-down direction that leads to the fourth chamber 123 (see FIG. 14).

[0074] Fig. 14 is an E-E cross-sectional view of Fig. 12. Frame 105 has fourth chamber 123 formed in an annular shape outside magnet 57. Both diametrical sides of the main body portion in the direction in which protruding portion 103 protrudes communicate with a pair of under-edge air passages 125 of the fourth chamber 123. That is, fourth chamber 123 communicates with third chamber 127 via under-edge air passage 125.

[0075] 13 again. The frame 105 has a fifth chamber 129 in a protruding portion 103 that extends radially outward from a portion of the outer periphery of the cylinder. The frame 105 has a third air passage 131 that connects the third chamber 127 to the fifth chamber 129. The frame 105 also has a fourth air passage 113 that opens the fifth chamber 129 to the outside of the frame 33.

[0076] The opening of the third air passage 131 of the microspeaker 97 is covered by the first mesh material 133, and the opening of the fourth air passage 113 is covered by the second mesh material 115. The first mesh material 133 and the second mesh material 115 determine the air resistance in the same manner as described above.

[0077] 15 is an explanatory diagram of the operation showing the air flow in the DD cross section of FIG. 12. In the microspeaker 97, when the voice coil 55 is driven to vibrate the diaphragm 35, the air under the dome 37 moves to the under-dome air passage 59 due to the displacement. The air in the under-dome air passage 59 is pushed by the movement of the air under the dome 37, and part or all of it moves to the third chamber 127. Similarly, the air under the edge 39 also moves to the under-edge air passage 125. The air in the under-edge air passage 125 is pushed by the movement of the air under the edge 39, and part or all of it moves to the third chamber 127. At this time, part or all of the air in the fourth chamber 123 communicating with the under-edge air passage 125 also moves to the third chamber 127.

[0078] As air moves from the under-dome air passage 59, the under-edge air passage 125, and the fourth chamber 123, a part or all of the air in the third chamber 127 moves through the third air passage 131 to the fifth chamber 129.

[0079] The air in fifth chamber 129 is pushed by the air moving from third air passage 131, and a part or all of the air moves through fourth air passage 113 to the outside of frame 33. If diaphragm 35 is displaced in the opposite direction, air moves from outside frame 105 to fifth chamber 129 through fourth air passage 113, and then the air moves into the gap below diaphragm 35 due to the reverse flow.

[0080] Next, the operation of the above-mentioned second embodiment will be described.

[0081] The microspeaker 97 is incorporated into the housing 15 of the earphone 99, and comprises a cylindrical frame 105 with a bottom, a diaphragm 35 provided at the opening of the frame 105 and having an edge 39 on the periphery of the dome 37, a cylindrical voice coil 55 fixed coaxially to the diaphragm 35, and an annular magnet 57 disposed within the frame 105 and having an under-dome air passage 59 at its center that is coaxial with the voice coil 55. The frame 105 includes a third chamber 127 formed on the opposite side of the diaphragm 35 with the magnet 57 in between, a fourth chamber 123 formed in an annular shape outside the magnet 57, an under-edge air passage 125 having one end opening opposite the edge 39, another end provided on the opposite side of the one end and communicating with the third chamber 127, and an intermediate portion provided between the one end and the other end and communicating with the fourth chamber 123, a protruding portion 103 extending radially outward from a portion of the outer periphery and having a fifth chamber 129, a third air passage 131 connecting the third chamber 127 to the fifth chamber 129, and a fourth air passage 113 opening the fifth chamber 129 to the outside of the frame 105. The under-edge air passage 125 and the fourth chamber 123 do not communicate directly with each other, but communicate with each other via the third chamber 127 and the third air passage 131. Moreover, the fourth chamber 123 and the fifth chamber 129 are directly connected to each other and form the same space.

[0082] This microspeaker 97 differs from the microspeaker 11 of embodiment 1 in that the fourth chamber 123 is in communication with the under-edge air passage 125 via the third chamber 127 and the third air passage 131, and in that the frame 105 has a fifth chamber 129 in the protruding portion 103 that extends radially outward.

[0083] In microspeaker 97 according to embodiment 2, the radial width of fourth chamber 123 in the main body of cylindrical frame 105 is smaller than that in embodiment 1. In microspeaker 97 according to embodiment 2, the outer diameter of the main body of frame 105 is the same, so that the radial width of fourth chamber 123 is reduced, making it possible to ensure a larger space for accommodating driver parts such as magnet 57 and voice coil 55.

[0084] The annular fourth chamber 123 communicates with the middle part of the under-edge air passage 125 at two points on both sides in the diameter direction. As a result, the fourth chamber 123 communicates with the third chamber 127 through the under-edge air passage 125.

[0085] A protruding portion 103 is formed in the frame 105, extending radially outward from a portion of the outer periphery. A fifth chamber 129 is formed inside this protruding portion 103. In the microspeaker 97, a large space is secured to accommodate the driver portion, and the reduction in volume caused by the reduction in the fourth chamber 123 is compensated for by providing the fifth chamber 129. The third chamber 127 communicates with the fifth chamber 129 through a third ventilation path 131. The fifth chamber 129 is opened to the outside of the frame 105 by the fourth ventilation path 113.

[0086] Therefore, in the microspeaker 97, when the voice coil 55 is driven, the diaphragm 35 vibrates, and the displacement of the air in the gap under the diaphragm causes the air in the under-dome air passage 59 and the under-edge air passage 125 to move. Accordingly, the air in the under-dome air passage 59 moves the air in the third chamber 127. Similarly, the air in the under-edge air passage 125 also moves the air in the third chamber 127. In other words, both the air in the under-dome air passage 59 and the air in the under-edge air passage 125 actuate the air in the third chamber 127. Since the under-edge air passage 125 is also connected to the fourth chamber 123, a part or all of the air in the fourth chamber 123 also moves to the third chamber 127.

[0087] The air that has moved to the third chamber 127 moves the air in the fifth chamber 129, which is in communication with the third air passage 131. When the air moves from the third air passage 131 to the fifth chamber 129, the air inside is pushed, and a part or all of the air moves to the outside of the frame 105 through the fourth air passage 113.

[0088] In the microspeaker 97, the volume within the frame through which air moves due to the displacement of the diaphragm 35 is composed of the under-dome air passage 59, the third chamber 127, the fourth chamber 123, the under-edge air passage 125, and the fifth chamber 129. These volumes are set to a size that allows the desired sound quality to be ensured. The third chamber 127 is formed as a flat space perpendicular to the axis of the frame 105 on the opposite side of the diaphragm 35 across the magnet 57. That is, the thickness in the direction along the axis of the frame 105 is suppressed. On the other hand, the fourth chamber 123, which communicates with the third chamber 127 via the under-edge air passage 125, is formed in a ring shape outside the magnet 57 between the diaphragm 35 and the third chamber 127.

[0089] In this microspeaker 97, by accommodating a large driver unit with a desired outer diameter, a fourth chamber 123 is secured in a frame thick portion 135 (see FIG. 14) which is the difference between the outer diameter of the remaining frame 105 and the outer diameter of the driver unit. In the second embodiment, the fourth chamber 123 is formed by effectively utilizing the remaining frame thick portion 135.

[0090] That is, in the microspeaker 97, a predetermined volume of empty spaces is secured by the third empty space 127, the fourth empty space 123, and the fifth empty space 129, thereby adjusting the sound quality and suppressing variations in sound quality. In the microspeaker 97, the fourth empty space 123 is disposed in an annular shape on the outside of the magnet 57, and the fifth empty space 129 is provided in the protruding portion 103 that protrudes from a part of the frame 105. This removes the volumes of the fourth empty space 123 and the fifth empty space 129 from the serial arrangement of the under-dome air passage 59 and the third empty space 127. As a result, the microspeaker 97 can be made thinner than the conventional configuration, without depending on the thickness of the fourth empty space 123.

[0091] Furthermore, in the microspeaker 97, the third air passage 131 and the fourth air passage 113 have a mesh material that determines the air resistance.

[0092] In this microspeaker 97, the third air passage 131 and the fourth air passage 113 have a mesh material that determines the air resistance. The mesh material can obtain a desired air resistance by changing the mesh size. The microspeaker 97 can change the sound pressure frequency characteristics to a desired one by changing the air resistance of at least one of the third air passage 131 and the fourth air passage 113. According to the microspeaker 97, the sound quality of the sound emitted from the diaphragm 35 can be controlled by the volumes of the third chamber 127, the fourth chamber 123, and the fifth chamber 129, and the air resistance, which is a characteristic of the mesh material.

[0093] Furthermore, the earphone 99 may not be symmetrical with respect to the axis of the sound conduit 25. In this case, surplus space 101 may exist around the microspeaker 97 in the accommodation space 21 of the earphone 99. When accommodating the microspeaker 97 with the protrusion 103, this surplus space 101 can be effectively utilized as the accommodation space 21 for the protrusion 103. In other words, by effectively utilizing the surplus space 101, the earphone 99 can adjust the sound quality and suppress variation in sound quality while suppressing the amount of protrusion from the ear canal to the outside, compared to the conventional configuration.

[0094] Therefore, the microspeaker 97 according to the second embodiment can be thinner than the conventional configuration while adjusting the sound quality and suppressing the variation in sound quality. Also, the earphone 99 according to the second embodiment can reduce the amount of protrusion from the ear canal to the outside when inserted, compared to the conventional configuration.

[0095] <About the technology disclosed herein> As described above, the present disclosure discloses the following technical ideas.

[0096] <Technology 1> A microspeaker (11) incorporated in a housing (15) of an earphone (13), A cylindrical frame (33) with a bottom; a diaphragm (35) provided in the opening of the frame and having an edge (39) on the periphery of a dome (37); A cylindrical voice coil (55) that is coaxially fixed to the diaphragm; an annular magnet (57) disposed within the frame and having a dome-under-ventilation passage (59) at its center that is coaxial with the voice coil; The frame is a first chamber (69) formed on the opposite side of the diaphragm with the magnet in between; A second chamber (71) formed in an annular shape outside the magnet; an under-edge ventilation passage (73) having one end portion that opens facing the edge portion and another end portion that is provided opposite to the one end portion and communicates with the first chamber; a first ventilation passage (75) that connects the first chamber to the second chamber; and a second air passage (43) that opens the second chamber to the outside of the frame. Micro speaker. As a result, the microspeaker secures a predetermined volume of empty space mainly in the first and second empty spaces to adjust the sound quality and suppress variation in sound quality, while arranging the second empty space in an annular shape outside the magnet removes that volume from the serial arrangement of the under-dome air passage and the first empty space, thereby suppressing the thickness of the microspeaker.As a result, the microspeaker can be made thinner than conventional configurations without relying on the thickness of the second empty space.

[0097] <Technology 2> The first air passage and the second air passage are disposed at different positions in the circumferential direction of the frame. A microspeaker according to <Technical 1>. This allows the second chamber to form a first air passageway that communicates with the first chamber on the inner circumferential side of the annular partition, and a second air passageway that communicates with the outside of the frame on the outer circumferential side of the annular partition. As a result, by arranging the first air passageway and the second air passageway in the annular partition at different circumferential positions in the second chamber, the frame can be prevented from becoming enlarged in the radial direction and can communicate the second chamber with both the first chamber and the outside of the frame with a compact structure.

[0098] <Technology 3> The first air passage and the second air passage have a mesh material that determines air resistance. A microspeaker according to <Technology 1> or <Technology 2>. This allows the microspeaker to change the sound pressure frequency characteristics to a desired one (in other words, obtain a desired sound pressure frequency characteristic) by changing the air resistance of at least one of the first and second air passages. That is, the sound pressure frequency characteristics that determine the quality of the sound emitted from the diaphragm can be controlled by the air resistance, which is a characteristic of the mesh material and the volumes of the first and second chambers.

[0099] <Technology 4> A micro-speaker (97) incorporated in a housing (15) of an earphone (99), A cylindrical frame (105) with a bottom; a diaphragm (35) provided in the opening of the frame and having an edge (39) on the periphery of a dome (37); A cylindrical voice coil (55) that is coaxially fixed to the diaphragm; an annular magnet (57) disposed within the frame and having a dome-under-ventilation passage (59) at its center that is coaxial with the voice coil; The frame is a third chamber (127) formed on the opposite side of the diaphragm with the magnet in between; a fourth chamber (123) formed in an annular shape outside the magnet; an under-edge ventilation passage (125) having one end opening opposite to the edge, another end provided on the opposite side to the one end and communicating with the third chamber, and an intermediate portion provided between the one end and the other end and communicating with the fourth chamber; a protrusion (103) extending radially outward from a portion of the outer periphery and having a fifth chamber (129); a third air passage (131) that connects the third chamber to the fifth chamber; and a fourth air passage (113) that opens the fifth chamber to the outside of the frame. Micro speaker. As a result, the microspeaker secures a predetermined volume of empty spaces in the third empty space, the fourth empty space 123, and the fifth empty space 129, thereby adjusting the sound quality and suppressing variations in sound quality. The microspeaker has the fourth empty space 123 arranged in an annular shape outside the magnet 57, and the fifth empty space 129 provided in the protruding portion 103 that protrudes from a part of the frame 105. As a result, the volumes of the fourth empty space 123 and the fifth empty space 129 are removed from the serial arrangement of the under-dome air passage 59 and the third empty space 127, realizing a reduction in the thickness of the microspeaker 97. As a result, the microspeaker 97 can be made thinner than the conventional configuration without depending on the thickness of the fourth empty space 123.

[0100] <Technology 5> The third air passage and the fourth air passage have a mesh material that determines air resistance. A micro speaker according to <Technical 4>. As a result, the earphone may not be symmetrical with respect to the axis of the sound guide tube. In this case, there may be excess space around the microspeaker in the housing space of the earphone. When housing a microspeaker with a protrusion, this excess space can be effectively used as a housing space for the protrusion. In other words, by effectively using the excess space, the earphone can adjust the sound quality and suppress variation in sound quality while keeping the amount of protrusion from the ear canal to the outside smaller than in conventional configurations.

[0101] <Technology 6> An earphone equipped with a microspeaker according to any one of <Technology 1> to <Technology 5>. This allows the earphone to house a microspeaker in its housing. The microspeaker can be thinner than conventional configurations while adjusting the sound quality and suppressing variation in sound quality, so the thickness dimension of the earphone housing can be reduced accordingly. This allows the earphone to keep the amount of protrusion from the ear canal to the outside smaller than conventional configurations.

[0102] Although various embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications, corrections, substitutions, additions, deletions, and equivalents within the scope of the claims, and it is understood that these also belong to the technical scope of the present disclosure. In addition, the components in the various embodiments described above may be arbitrarily combined within the scope of the invention. [Industrial Applicability]

[0103] INDUSTRIAL APPLICABILITY The present disclosure is useful as a microspeaker and earphone that can adjust sound quality and suppress variation in sound quality while being thinner than conventional configurations. [Explanation of symbols]

[0104] 11...Micro speaker 13. Earphones 15…Housing 33…Frame 35...Diaphragm 37…Dome 39…Edge 43…Second air passage 45…Second mesh material (mesh material) 55…Voice coil 57…Magnet 59…Under-dome ventilation passage 69…First vacancy 71…Second vacant room 73…Under-edge ventilation channel 75…First ventilation passage 81…First mesh material (mesh material) 97...Micro speaker 99…Earphones 103...Protrusion 105…Frame 113…4th air passage 115…Second mesh material (mesh material) 123…4th vacant room 125…Under-edge ventilation channel 127…3rd vacant room 129…5th vacant room 131…Third air passage 133…First mesh material (mesh material)

Claims

1. A micro speaker incorporated in an earphone housing, A cylindrical frame with a bottom; a diaphragm provided in the opening of the frame and having an edge on the periphery of the dome; A cylindrical voice coil fixed coaxially to the diaphragm; an annular magnet disposed within the frame and having an under-dome air passage at its center that is coaxial with the voice coil; The frame is a first cavity formed on the opposite side of the diaphragm with the magnet in between; a second chamber formed in an annular shape outside the magnet; an under-edge ventilation passage having one end portion that opens facing the edge portion and another end portion that is provided opposite to the one end portion and communicates with the first chamber; A first ventilation passage that connects the first chamber to the second chamber; A second air passage that opens the second chamber to the outside of the frame. Micro speaker.

2. The first air passage and the second air passage are disposed at different positions in a circumferential direction of the frame.

2. The microspeaker of claim 1.

3. The first air passage and the second air passage have a mesh material that determines air resistance.

2. The microspeaker of claim 1.

4. A micro speaker incorporated in an earphone housing, A cylindrical frame with a bottom; a diaphragm provided in the opening of the frame and having an edge on the periphery of the dome; A cylindrical voice coil fixed coaxially to the diaphragm; an annular magnet disposed within the frame and having an under-dome air passage at its center that is coaxial with the voice coil; The frame is a third chamber formed on the opposite side of the diaphragm with the magnet in between; a fourth chamber formed in an annular shape outside the magnet; an under-edge ventilation passage having one end portion that opens facing the edge, another end portion that is provided on the opposite side to the one end portion and that communicates with the third chamber, and an intermediate portion that is provided between the one end portion and the other end portion and that communicates with the fourth chamber; a protrusion extending radially outward from a portion of the outer periphery and having a fifth chamber; A third ventilation passage that connects the third chamber to the fifth chamber; A fourth air passage that opens the fifth chamber to the outside of the frame. Micro speaker.

5. The third air passage and the fourth air passage have a mesh material that determines air resistance.

5. The microspeaker according to claim 4.

6. A microspeaker according to any one of claims 1 to 5, Earphones.

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