JP2013021565A - Electrodynamic speaker and display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a thin type electrodynamic speaker with a low overall height which includes a second diaphragm that vibrates in a direction substantially orthogonal to a first diaphragm, has excellent sound reproduction performance and, is suitably attached to equipment, such as a display; and a display device using the thin type electrodynamic speaker.SOLUTION: An electrodynamic speaker includes: a first diaphragm and a first voice coil; a second diaphragm that vibrates in a second axial direction substantially orthogonal to a first axial direction, and a second voice coil; and a magnetic circuit which includes a magnet, a first yoke and a second yoke, and has a first magnetic gap and a second magnetic gap. The magnetic circuit forms the first magnetic gap between the first yoke and the second yoke, and forms the second magnetic gap between a first extended part that is extended from a bottom part of the first yoke to an outer peripheral side thereof, and a second extended part that is extended toward an outer peripheral side of the second yoke.

Description

  A thin electrodynamic speaker with a low overall height, which is equipped with a second diaphragm that vibrates in a direction substantially orthogonal to the first diaphragm, has excellent sound reproduction capability, and is attached to a device such as a display. Electrodynamic type speaker suitable for

  In an audio device such as a display to which a speaker for reproducing sound is attached, it is desired to reduce the space required for attaching the speaker. When emphasizing the design of liquid crystal displays, the diaphragm of the electrodynamic speaker should be exposed from the back side of the liquid crystal display in order to minimize the frame around the liquid crystal display when viewed from the front. In some cases, the front side is not exposed. In particular, in an electrodynamic speaker that is thinned so as to reduce the overall height, which is the distance from the front end portion of the front frame to the magnetic circuit on the back side, the shape of the speaker diaphragm or the center support of the voice coil There may be a limit depending on the structure.

  Specifically, even if the damper that supports the voice coil at the center becomes closer to the magnetic circuit due to the reduction in thickness, it is necessary to take care not to generate abnormal noise by contacting the magnetic circuit. In the electrodynamic speaker, there is a problem that it becomes easy for the damper to collide with the magnetic circuit and generate abnormal noise at a frequency below the lowest resonance frequency f0 where the vibration system is greatly displaced. Therefore, conventionally, various electrodynamic speakers have been proposed in order to solve such problems.

  Conventionally, an annular top plate having two linear portions parallel to the inner peripheral side, a pole having two protrusions cut and raised from the under plate on the inner peripheral side, and a top plate and an under plate of the pole And two rod-shaped magnets sandwiched between them and magnetized in the same direction, with the two protrusions of the pole facing the two straight portions of the top plate, respectively, between the two rod-shaped magnets Two magnetic air gaps are formed, the two protrusions of the pole form a through hole therebetween, and the top plate, the under plate, and the two rod-shaped magnets communicate with the through hole 2. There is an electrodynamic speaker including a speaker magnetic circuit that forms two internal spaces (Patent Document 1).

  Further, conventionally, there is provided a magnetic circuit for a speaker comprising a rod-shaped magnet having a rectangular cross section forming a linear magnetic gap, and a U-shaped or annular yoke connected to the magnet at a mounting portion. However, the cross section of the portion not including the mounting portion is formed in a substantially rectangular shape, the cross section of the portion including the mounting portion is formed in a substantially L shape, and the mounting portion is a rectangular shape that engages with a magnet having a rectangular cross section. There is an electrodynamic type speaker provided with a magnetic circuit for a speaker which is a concave portion forming a space (Patent Document 2).

  Further, conventionally, the first coil and the second coil, which are flat-plate air-core coils in which a flat wire is wound without being shifted with respect to the winding axis, are connected to the coil end faces so that the respective winding axes coincide with each other. A first coil and a second coil, which are formed by bonding together, and the first and second coils bonded together are connected in series or in parallel so that audio signal current flows in the same direction. Including a voice coil including a reinforcing plate that is housed in an inner circumferential space defined by an inner circumferential end formed by bonding the second coil and that has an outer circumferential end engaged with the inner circumferential end. There is a type speaker (Patent Document 3).

JP 2010-103891 A (FIGS. 1 to 9) JP 2010-272988 (FIGS. 1 to 6) JP 2011-114857 A (FIGS. 1 to 7)

  However, when the electrodynamic speakers of Patent Documents 1 to 3 are attached to the display device so that the diaphragm is not exposed on the front side, there is a problem that the reproduction level of the mid-high range tends to decrease. For example, if the electrodynamic speaker of Patent Documents 1 to 3 is attached to the display device so that the diaphragm is exposed on the back side, that is, the sound is emitted to the back side, the display device can be thinned. On the other hand, there is a problem that the reproduction level in the middle / high range, which is difficult to go around to the front side, is lowered and the reproduction sound quality is lowered.

  The present invention has been made in order to solve the above-described problems of the prior art, and an object thereof is a thin electrodynamic speaker having a low overall height, which vibrates in a direction substantially orthogonal to the first diaphragm. The present invention relates to an electrodynamic speaker including the second diaphragm, and to provide a thin electrodynamic speaker excellent in sound reproduction capability and suitable for being attached to a device such as a display, and a display device using the same.

  The electrodynamic speaker of the present invention includes a first diaphragm that vibrates in a first axial direction, a first voice coil that is coupled to the first diaphragm, and a second axial direction that is substantially orthogonal to the first axial direction. A second diaphragm that vibrates to the second diaphragm, a second voice coil coupled to the second diaphragm, a magnet, a first yoke coupled to the bottom surface of the magnet, a second yoke coupled to the top surface of the magnet, The first voice coil is disposed so as to be able to vibrate in the first axial direction, and the second voice coil is disposed so as to be capable of vibrating in the second axial direction. A magnetic circuit, wherein the magnetic circuit forms a first magnetic gap between a first side wall portion formed by being cut and raised from a bottom portion of the first yoke and an inner peripheral end portion of the second yoke, and The first extending portion formed by extending from the bottom of the one yoke to the outer peripheral side and the second yoke Extending in the circumferential side to form a second magnetic gap between the second extending portion which is formed.

  The electrodynamic speaker according to the present invention has a substantially cylindrical shape in which the first voice coil is wound around a bobbin with a round wire or a rectangular wire obliquely shifted with respect to the first winding axis that coincides with the vibration direction. The first voice coil includes a flat coil that is formed by multilayer winding without shifting the flat wire with respect to the second winding axis that is substantially orthogonal to the vibration direction. The second voice coil is connected in series or in parallel.

  In the electrodynamic speaker of the present invention, the first magnetic gap and the second magnetic gap of the magnetic circuit are both linear gaps, and the first voice coil and the second voice coil are the first magnetic gap and the magnetic gap, respectively. It is formed in a track shape including a straight portion arranged in the second magnetic gap.

  In the electrodynamic speaker of the present invention, the first magnetic gap of the magnetic circuit is configured as a pair of linear gaps arranged in parallel, and the pair of linear portions of the track-shaped first voice coil vibrate respectively. Arranged as possible.

  In addition, the electrodynamic speaker of the present invention is connected to the frame connected to the magnetic circuit, the outer peripheral end of the first diaphragm and the first edge connected to the frame, the outer peripheral end of the second diaphragm and the frame. A second edge.

  The electrodynamic speaker according to the present invention is formed between an inner periphery fixing portion connected to the bobbin of the first voice coil, an outer periphery fixing portion connected to the frame, and the inner periphery fixing portion and the outer periphery fixing portion. A support formed between a first damper having a support movable part, an inner peripheral fixing part connected to the second voice coil, an outer peripheral fixing part connected to the frame, and an inner peripheral fixing part and an outer peripheral fixing part. And a second damper having a movable part.

  Moreover, the display device of the present invention is a display device including any one of the above-described electrodynamic speakers, and the first diaphragm and the two substantially perpendicular surfaces constituting the corners of the casing of the display device, respectively. An electrodynamic speaker is attached so that the second diaphragm is exposed.

  The operation of the present invention will be described below.

  The electrodynamic speaker of the present invention has an electrodynamic speaker having a first diaphragm that vibrates in a first axial direction and a second diaphragm that vibrates in a second axial direction substantially orthogonal to the first axial direction. Type speaker. Although the first and second axial directions can be arbitrarily set, the first axial direction can be set to a direction that defines the overall height or thickness of the electrodynamic speaker, for example, and the second axis The direction may be a direction in which the electrodynamic speaker is viewed from the side.

  The electrodynamic speaker includes a first voice coil coupled to the first diaphragm, a second voice coil coupled to the second diaphragm, a magnet, a first yoke coupled to the bottom side of the magnet, A first yoke that is coupled to the top surface, the first voice coil being arranged to vibrate in the first axial direction, and the second voice coil vibrating in the second axial direction. And a magnetic circuit having a second magnetic air gap that is arranged in a possible manner. A frame connected to the magnetic circuit, a first edge connected to the outer peripheral end of the first diaphragm and the frame, and a second edge connected to the outer peripheral end of the second diaphragm and the frame are further provided. Just do it.

  Specifically, the magnetic circuit forms a first magnetic gap between a first side wall portion formed by being cut and raised from a bottom portion of the first yoke and an inner peripheral end portion of the second yoke, and the first yoke. A second magnetic gap is formed between a first extending portion formed extending from the bottom of the outer periphery to the outer peripheral side and a second extending portion formed extending from the outer peripheral side of the second yoke. Therefore, since the electrodynamic speaker of the present invention has the first diaphragm and the second diaphragm capable of reproducing sound in the first and second axial directions that are substantially orthogonal to each other, it can be used in a device such as a display. A thin electrodynamic speaker suitable for mounting can be realized.

  That is, in a display device or the like that is required to reduce the space required for mounting the speaker, the diaphragm is obtained by adding the second diaphragm to the first diaphragm as compared with the speaker having the same volume or surface area. Since the area can be increased, the reproduction sound pressure level of the electrodynamic speaker can be increased. The first diaphragm and the second diaphragm are exposed on the two surfaces constituting the corner portion of the casing of the display device, that is, the sound is emitted in two directions parallel to the two surfaces constituting the corner portion. If it is attached to the display device so as to radiate, an electrodynamic speaker can be attached, so that it is possible to improve the sound reproduction conditions even under restrictive attachment conditions. For example, when the electrodynamic speaker is attached to the display device so that the diaphragm is not exposed to the front surface side, the first vibration is applied even if the first diaphragm is attached to the display device so as to be exposed to the rear surface side of the display device. The second diaphragm that can vibrate in a direction substantially orthogonal to the plate is the surface that defines the thickness of the display device (the surface in any one of the upward, downward, and lateral directions that is substantially orthogonal to the back surface Side). Therefore, a decrease in the reproduction level in the middle and high sound range of the first diaphragm arranged on the back side can be compensated by the other second diaphragm, and the reproduction sound quality can be improved.

  Here, the first voice coil includes a substantially cylindrical coil formed by winding a round wire or a rectangular wire obliquely with respect to the first winding axis coinciding with the vibration direction and winding it around a bobbin. It is preferable that the voice coil includes a flat coil formed by multilayer winding without shifting the flat wire with respect to the second winding axis that is substantially orthogonal to the vibration direction. Since the second voice coil is a flat coil in which the winding axis direction is parallel to the first voice coil, the second voice coil can be a flat coil having a very thin thickness along the winding axis direction. Therefore, the electrodynamic speaker according to the present invention vibrates in the second axial direction substantially orthogonal to the first axial direction even if it is a thin electrodynamic speaker having a small first axial dimension that defines the overall height. A second diaphragm and a second voice coil can be provided. The first voice coil and the second voice coil may be connected in series or in parallel.

  Specifically, the first magnetic gap and the second magnetic gap of the magnetic circuit are both linear gaps, and the first voice coil and the second voice coil are disposed in the first magnetic gap and the second magnetic gap, respectively. Preferably, it is formed in a track shape including a straight portion. Both the first magnetic gap and the second magnetic gap are linear gaps that are substantially orthogonal to the first axial direction that defines the overall height, and the corresponding track-shaped first voice coil and second voice coil are disposed. Thus, the length of the coil disposed in the magnetic gap can be increased without increasing the overall height of the electrodynamic speaker. Further, if the first magnetic gap of the magnetic circuit is configured as a pair of linear gaps arranged in parallel, the pair of linear portions of the track-shaped first voice coil are arranged so as to be able to vibrate, respectively. Even a thin electrodynamic speaker can sufficiently increase the driving force generated in the first voice coil.

  The electrodynamic speaker according to the present invention is formed between an inner periphery fixing portion connected to the bobbin of the first voice coil, an outer periphery fixing portion connected to the frame, and the inner periphery fixing portion and the outer periphery fixing portion. A first damper having a support movable part, or an inner peripheral fixing part connected to the second voice coil, an outer peripheral fixing part connected to the frame, and an inner peripheral fixing part and an outer peripheral fixing part. And a second damper having a support movable part. The first damper and the second damper perform the center holding of the first voice coil with respect to the first magnetic gap and the center holding of the second voice coil with respect to the second magnetic gap, respectively, so that the vibration including the voice coil and the diaphragm is included. It is possible to realize a thin electrodynamic speaker that suppresses abnormal noise generated when the system and the magnetic circuit collide, and has excellent sound reproduction capability.

  With regard to a thin electrodynamic speaker having a low overall height, it is possible to provide a thin electrodynamic speaker excellent in sound reproduction capability and suitable for being attached to a device such as a display and a display device using the same.

It is a figure explaining the electrodynamic speaker 1 by preferable embodiment of this invention. Example 1 1 is a perspective view illustrating an electrodynamic speaker 1 according to a preferred embodiment of the present invention. Example 1 It is an expanded view explaining the structure of the electrodynamic speaker 1 by preferable embodiment of this invention. Example 1 It is sectional drawing explaining the electrodynamic speaker 1 by preferable embodiment of this invention. Example 1 It is a perspective view explaining the magnetic circuit 10 which comprises the electrodynamic speaker 1 by preferable embodiment of this invention. Example 1 It is a rear view explaining the display apparatus 20 provided with the electrodynamic speaker 1 by preferable embodiment of this invention. (Example 2) It is sectional drawing explaining the display apparatus 20 provided with the electrodynamic speaker 1 by preferable embodiment of this invention. (Example 2) It is a perspective view explaining the display apparatus 20 provided with the electrodynamic speaker 1 by preferable embodiment of this invention. (Example 2)

  Hereinafter, although the electrodynamic speaker by preferable embodiment of this invention is demonstrated, this invention is not limited to these embodiment.

  1 to 5 are diagrams for explaining an electrodynamic speaker 1 according to a preferred embodiment of the present invention. 1A is a plan view of the electrodynamic speaker 1 as viewed from the Z-axis side, FIG. 1B is a side view of the electrodynamic speaker 1 as viewed from the X-axis side, and FIG. It is the side view seen from the Y-axis side. FIG. 2 is a perspective view of the electrodynamic speaker 1, and FIG. 3 is a development view illustrating the configuration of the electrodynamic speaker 1. 4 is a cross-sectional view of the electrodynamic speaker 1, and FIG. 5 is a perspective view illustrating the magnetic circuit 10 constituting the electrodynamic speaker 1. FIG. As will be described later, a part of the structure of the electrodynamic speaker 1, the internal structure, and the like are omitted. The direction in which the Z axis extends is the height direction that defines the overall height or thickness, the direction in which the Y axis (long axis) extends is the major axis direction, and the direction in which the X axis (minor axis) extends is the minor axis direction. It is.

  The electrodynamic speaker 1 of this embodiment is an elongated and thin electrodynamic speaker having a major axis length of about 150.0 mm, a minor axis direction length of about 52.5 mm, and an overall height of 11.0 mm. The electrodynamic speaker 1 includes a first diaphragm 2a that vibrates in the Z-axis direction and a second diaphragm 2b that vibrates in the X-axis direction orthogonal to the Z-axis direction. In the electrodynamic speaker 1, the first diaphragm 2 a and the second diaphragm 2 b are independent diaphragms, but the frame 6 and the magnetic circuit 10 connected to the frame 6 have a common configuration. The frame 6 has an elongated shape corresponding to each of the track-shaped diaphragms 2a and 2b, and the magnetic circuit 10 fixed so as to be accommodated in the frame 6 also has an elongated shape having a narrow width in the minor axis direction. ing. Therefore, the electrodynamic speaker 1 is a speaker suitable for a device with a small width for mounting the speaker, such as a side surface or an edge of a display unit included in a device such as a display. A terminal 7 (not shown) to which an audio signal current is supplied is attached to the back side of the frame 6 and a part of the magnetic circuit 10 is exposed.

  The outer periphery of the first diaphragm 2 a is supported by the first edge 3 a, and the outer periphery of the first edge 3 a is fixed to the first frame portion 6 a of the frame 6. On the other hand, the outer periphery of the second diaphragm 2 b is supported by the second edge 3 b, and the outer periphery of the second edge 3 b is fixed to the second frame portion 6 b of the frame 6. A first voice coil 4a is connected to the back side of the first diaphragm 2a, and is supported by the first damper 5a so as to vibrate. The second voice coil 4b is connected to the back side of the second diaphragm 2b and is supported by the second damper 5b so as to vibrate.

  The first diaphragm 2a of the electrodynamic speaker 1 is formed by forming a foamed thermoplastic resin in order to reduce the weight of the speaker diaphragm. In the case of the present embodiment, the first diaphragm 2a having irregularities is formed by using a thermoplastic resin foam sheet (specifically, polystyrene paper) that is formed by extrusion using a vacuum forming method in combination with plug assist molding. Have gained. In other words, the elongated first diaphragm 2a, whose major axis direction length is significantly different from the major axis direction length, is likely to be noticeably affected by the split vibration in the major axis direction, so that the sectional shape of the minor axis direction is partially U-shaped. It is made into the shape which has rigidity in a major axis direction so that it may become a shape to include. The first diaphragm 2a has an inner peripheral side of the first edge 3a bonded to the outer peripheral end thereof, and a bobbin constituting the voice coil 4 is bonded to the center rear surface. The first diaphragm 2a may be configured to include a base body made of a paper material formed by making paper fibers.

  The second diaphragm 2b of the electrodynamic loudspeaker 1 is configured to include a substrate whose base material is a paper material formed by making paper fibers in order to reduce the weight of the speaker diaphragm. In the case of the present embodiment, the second diaphragm 2b is a substantially cone-shaped diaphragm having a smaller diaphragm area and higher rigidity than the first diaphragm 2a. Specifically, it is a speaker diaphragm in which a base body made of a paper material obtained by making paper fiber is formed. The second diaphragm 2b, like the substantially cone-shaped first diaphragm 2a, is prone to the influence of divided vibration in the major axis direction, so that the minor axis cross-sectional shape becomes a cone shape including a substantially U-shape. Thus, the shape has rigidity in the major axis direction. The second diaphragm 2b defines a convex ridge line portion on the front surface side on a diaphragm surface having a cone-shaped cross section, and an engagement recess in which a voice coil is engaged with a part on the back surface side of the ridge line portion. And a rib defining the above. That is, this rib is a rib formed in the major axis direction of the second diaphragm 2b, and forms an engaging recess with which the second voice coil is engaged on the central back side and is convex on the front side. What is necessary is just a rib which prescribes | regulates a ridgeline part. Further, the second diaphragm 2b has an inner peripheral side of the second edge 3b bonded to an outer peripheral end thereof.

  In the present embodiment, the first edge 3a and the second edge 3b are formed by injecting flexible foam rubber into a mold and heating and foaming. The first edge 3a has a track-shaped long side extending linearly in the major axis direction of the first diaphragm 2a, and a free edge is formed by a thin corrugation (or roll) so as to freely support the first diaphragm 2a. On the short side of the track shape having an arc shape in the minor axis direction, a fixed edge that is thick and does not vibrate freely is formed so as to fix and support the first diaphragm 2a. As a result, the elongated first diaphragm 2a is flexibly supported by the compliance of the free edge portion of the edge 3 in the minor axis direction, while foaming of the thermoplastic resin forming the first diaphragm 2a in the major axis direction. Bending vibration is made possible by the flexibility of the sheet. On the other hand, the second edge 3b forms a free edge by thin corrugation (or roll) so as to freely support the second diaphragm 2b over the entire circumference of the track shape. In addition, you may comprise the 1st edge 3a and the 2nd edge 3b with elastic bodies, such as a non-foamed nitrile rubber (NBR).

  The first voice coil 4a is formed of a track-shaped bobbin and a track-shaped coil that is wound around one end thereof and supplied with an audio current. In the case of the present embodiment, the first voice coil 4a has a track shape having a major axis direction length of about 33.0 mm and a minor axis direction length of about 14.5 mm. The other end of the bobbin where the coil is not wound is connected to the center of the back surface of the first diaphragm 2a by an adhesive. The coil is a substantially cylindrical coil formed by winding a round wire or a rectangular wire obliquely around a bobbin with respect to the first winding axis that coincides with the Z-axis direction that is the vibration direction. Since the track-shaped bobbin and coil of the first voice coil 4a include two straight portions along the major axis direction, the two straight portions of the coil are respectively disposed in magnetic gaps 13a and 13b of the magnetic circuit 10 described later. The

  The second voice coil 4b is a flat coil having a winding direction in the Z direction substantially orthogonal to the X axis direction in which the second diaphragm 2b vibrates, corresponding to the magnetic circuit 10 described later. The coil has a track shape with a major axis length of about 36.0 mm, a minor axis length of about 8.0 mm, and a thickness 4t of about 0.5 mm. Specifically, the second voice coil 4b includes two air-core coils 41 and 42 formed in a flat plate shape and a reinforcing plate 43 described later. Each of the coils 41 and 42 is formed by winding a copper clad aluminum flat wire having a thickness of 0.11 mm × 0.22 mm into a multi-layer winding without shifting with respect to the winding axis, and the thickness (41t to 42t) is a thick flat wire. This is an air-core coil formed in a flat plate shape having a thickness dimension approximately equal to about 0.22 mm and a winding layer thickness dimension of about 0.5 mm. The coils 41 and 42 constituting the second voice coil 4b of the present embodiment are coils having substantially the same number of turns. The second voice coil 4b is formed by bonding the coil end faces so that the winding axes of the coils 41 and 42 coincide with each other with an adhesive (or varnish), and the bonded coils 41 and 42 are the same. It is a voice coil configured to be connected in series so that an audio signal current flows in the direction. Since the coils 41 and 42 are wound in multiple layers without shifting the rectangular wire with respect to the winding axis, there is a problem that each of the coils 41 and 42 is easily warped and deformed. It can prevent and keep a flat plate shape.

  In the track-shaped second voice coil 4b to which the coils 41 and 42 are bonded, one linear portion, the other linear portion, one arc portion, and the other arc portion are formed, and the track-shaped second voice coil 4b is formed. An inner peripheral space that is a track-shaped hole is formed on the inner peripheral side of the inner peripheral end. Therefore, in the coil 4, the outer peripheral end portion of the reinforcing plate 43 accommodated in the inner peripheral space engages with the track-shaped inner peripheral end portion. The reinforcing plate 43 has an outer peripheral end engaged with a track-shaped inner peripheral end of the second voice coil 4b and is bonded with an adhesive. That is, the outer peripheral end of the reinforcing plate 43 is engaged with the inner peripheral surface of the innermost winding of the coils 41 and 42. The reinforcing plate 43 of this embodiment is an aluminum plate having a thickness 43t of about 0.14 mm, and has a track shape having a major axis length of about 31.5 mm and a minor axis direction length of about 3.5 mm. Since the thickness 43t of the reinforcing plate 43 is made smaller than the voice coil thickness dimension 4t defined by the thickness of the coils 41 and 42 bonded together, the reinforcing plate 43 does not protrude from the inner peripheral space of the second voice coil 4b. . Since the reinforcing plate 43 increases the rigidity of the second voice coil 4b, the reinforcing plate 43 suppresses deformation such that the flat plate-like second voice coil 4b is warped. The reinforcing plate 43 may be made of a nonmagnetic metal such as copper, duralumin, or an aluminum alloy, but may be made of a resin such as ABS, PI, or PET. Further, the shape of the reinforcing plate 43 is not limited to a flat plate shape as in the present embodiment.

  In addition, the tinsel wire (not shown) is soldered to a terminal 7 (not shown) fixed to the frame 6 and a lead wire of each of the first voice coil 4a or the second voice coil 4b from the terminal 7. Then, the electric current is supplied to the coil. However, the tinsel wire may be electrically connected to the terminal 7 by providing a metal eyelet on the first diaphragm 2a. In the present embodiment, the first voice coil 4a and the second voice coil 4b are connected in series, but may be connected in parallel.

  The first damper 5a is formed by cutting an elongated corrugation damper formed by impregnating a phenolic resin with a woven fabric of flexible fibers as a base material and forming an overall shape. Specifically, the first damper 5a includes two inner fixing portions that are connected to the end side around which the coil of the bobbin is wound, an outer fixing portion that is fixed to the top plate 11 of the magnetic circuit 10, and an inner fixing portion. And two movable parts that connect the outer fixed part and an inner flat part that connects the two inner fixed parts. The two movable parts of the damper located in the major axis direction have a substantially fan shape and have corrugations, and are respectively disposed in the internal spaces 16a and 16b of the magnetic circuit 10 as described later. The inner flat portion of the damper is an elongated strip-shaped flat portion, and connects the two inner fixing portions across the through hole 14 of the magnetic circuit 10 along the major axis direction.

  The second damper 5b is provided with a notch portion (slit portion) in a thin plate-like resin plate, and an inner fixing portion connected to the second voice coil 4b, and an outer fixing portion connected to the second frame portion 6b of the frame 6. A damper having an arm-shaped movable portion that connects the inner fixed portion and the outer fixed portion. Specifically, the second damper 5b is a member formed by pressing a PC resin plate having a thickness of about 0.2 mm, and the inner fixing portion includes the arc portion of the second voice coil 4b, The reinforcing plate 43 of the two voice coil 4b is inserted and fixed. The second damper 5b is connected to the second voice coil 4b or the frame 6 by an adhesive. The second damper 5b may be a damper formed by injection molding of a resin, or may be formed by impregnating a phenol resin with a flexible fiber woven fabric as a base material. Good.

  The frame 6 is an iron plate frame including a first frame portion 6a and a second frame portion 6b that are press-molded into an elongated basket shape corresponding to each diaphragm shape. The frame 6 further includes a fixing portion for fixing the magnetic circuit 10, a connecting portion for connecting these fixing portions, a window defined between the plurality of connecting portions, and a mounting hole for attaching the terminal 7 (not shown). . The first frame portion 6a and the second frame portion 6b each include a substantially rectangular fixing portion that fixes the first edge 3a or the second edge 3b, and a mounting portion to the display device described later. Therefore, the speaker vibration system including the first diaphragm 2a, the first edge 3a, the first voice coil 4a, and the first damper 5a can vibrate in the Z-axis direction with respect to the first frame portion 6a and the magnetic circuit 10. Supported by The speaker vibration system including the second diaphragm 2b, the second edge 3b, the second voice coil 4b, and the second damper 5b can vibrate in the X-axis direction with respect to the second frame portion 6b and the magnetic circuit 10. Supported by Therefore, as will be described later, the electrodynamic speaker 1 can be attached so that the first diaphragm and the second diaphragm are exposed on the two surfaces constituting the corner portion of the casing of the display device. .

  The magnetic circuit 10 includes an elongated top plate 11, an elongated pole 12, and two rod-shaped magnets 15a and 15b magnetized in the same direction. The magnetic circuit 10 includes first magnetic air gaps 13a and 13b in which the first voice coil 4a is arranged so as to be able to vibrate in the Z-axis direction, and second magnetic material in which the second voice coil 4b is arranged so as to be able to vibrate in the X-axis direction. There is a gap 13c. Each member constituting the magnetic circuit 10 is fixed with an adhesive. The magnetic circuit 10 is also fixed to the fixing portion of the frame 6 with an adhesive. The magnetic circuit 10 is a thin magnetic circuit having an overall height of about 6.8 mm. Since the entire magnetic circuit 10 is accommodated inside the frame 6, the electrodynamic speaker 1 can be thinned.

  The top plate 11 is formed of a soft iron steel material having a thickness of 1.6 mm in an annular shape having two straight portions 11a and 11b parallel to the inner peripheral side, and is further extended to one outer peripheral side in the X-axis direction. It is a member formed so that it may have the extending part 11c formed. The two linear portions 11a and 11b are provided along the major axis direction, have a length of 24.0 mm, and form magnetic gaps 13a and 13b described later. That is, the inner peripheral side of the top plate 11 has a shape in which two long straight portions 11a and 11b extending in the major axis direction from the inner peripheral side of the rectangular ring protrude into a trapezoidal shape, and the two straight lines The annular inner peripheral side other than the portions 11 a and 11 b does not act as a magnetic gap that generates a driving force for the voice coil 4. Further, on the outer peripheral side of the top plate 11, an extending portion 11c that forms a magnetic gap 13c described later is extended.

  The pole 12 is a member having two projecting portions 12a and 12b cut and raised from the under plate on the inner peripheral side and an extending portion 12c corresponding to the extending portion 11c of the top plate 11 on the outer peripheral side. Specifically, a substantially H-shaped hole is provided on the inner peripheral side of a 1.6 mm-thick soft iron steel material constituting the under plate, and these are cut and raised from the inner peripheral side, so that two protrusions 12a and 12b are provided. In addition, an extending portion 12c that forms a magnetic gap 13c, which will be described later, is extended on the outer peripheral side. In the pole 12, the straight hole of the horizontal bar portion constituting the substantially H-shaped hole is along the major axis direction so that the two protrusions 12 a and 12 b face the two straight parts of the top plate, respectively. Placed in the direction The pole 12 may be implemented in a single process of punching and bending.

  The two rod-shaped magnets 15a and 15b are rare earth magnets each having a major axis length of 50.0 mm, a minor axis direction length of 6.0 mm, and a thickness of 3.0 mm, and may be ferrite magnets. The rare earth magnet is an Nd—Fe—B type neodymium magnet or an Sm—Co type samarium cobalt magnet, which has a large maximum energy product (BH) max, An Nd—Fe—B rare earth magnet having a larger magnetization and coercive force and a strong coercive force even in a small volume may be used.

  Therefore, in the magnetic circuit 10, the two protrusions 12 a and 12 b of the pole 12 are disposed between the two bar-shaped magnets 15 a and 15 b so as to face the two straight portions 11 a and 11 b of the top plate 11, respectively. Two magnetic gaps 13a and 13b are formed. The two magnetic air gaps 13a and 13b that enable the first voice coil 4a to vibrate in the Z-axis direction are provided along the Y-axis direction that is the major axis direction, and the two protrusions 12a and 12b of the pole 12 are A substantially rectangular through hole 14 is formed between them. The top plate 11, the underplate of the pole 12, and the two rod-shaped magnets 15 a and 15 b form two internal spaces 16 a and 16 b that communicate with the through hole 14. In the elongated magnetic circuit 10 of this embodiment, the two internal spaces 16a and 16b are disposed along the major axis direction with the through hole 14 interposed therebetween.

  Further, the magnetic circuit 10 is formed between the extended portion 12c formed to extend from the bottom of the pole 12 to the outer peripheral side and the extended portion 11c formed to extend to the outer peripheral side of the top plate 11. Two magnetic gaps 13c are formed. The magnetic gap 13c that enables the second voice coil 4b to vibrate in the X-axis direction is provided along the Y-axis direction, which is the major axis direction. In the present embodiment, the second magnetic gap 13c is formed by the extending portions 11c and 12c extending in the X-axis direction. However, the second magnetic gap 13c is within a range that can be said to be a direction substantially orthogonal to the Z-axis direction. The extending portions 11c and 12c may be slightly bent in a predetermined direction so as not to be orthogonal to the magnetic air gaps 13a and 13b.

  FIG. 4 is an enlarged view of the AO-A ′ cross section along the minor axis direction for explaining the configuration in the vicinity of the magnetic circuit 10 of the electrodynamic speaker 1 of the present embodiment. In the electrodynamic speaker 1, when an audio current is supplied to the coil of the first voice coil 4a, a driving force is applied to the linear portion of the first voice coil 4a disposed in the magnetic gaps 13a and 13b. The voice coil 4a vibrates in the Z-axis direction, and the connected first diaphragm 2a also vibrates in the Z-axis direction. In the minor axis direction, the first diaphragm 2a is flexibly supported by the free edge portion of the first edge 3a that supports the outer peripheral end of the first diaphragm 2a. On the other hand, in the major axis direction, bending vibration is possible due to the flexibility of the thermoplastic resin foam sheet forming the first diaphragm 2a, and the first voice coil 4a is greatly displaced at a frequency near or below the lowest resonance frequency f0. In this case, the first diaphragm 2a fixed at both ends in the major axis direction is bent and deformed in an arc shape in the major axis direction.

  The first damper 5 a that supports the track-shaped first voice coil 4 a so as to be able to vibrate is fixed at its outer fixing portion on the plane of the annular top plate 11 that constitutes the magnetic circuit 10. The two inner fixed portions connected to the first voice coil 4a of the first damper 5a are arc-shaped concave portions corresponding to the short-diameter side of the track shape, and are end portions on the side around which the coil of the bobbin is wound It is a part fixed so that may be mounted. Therefore, in the 1st damper 5a, the inner side flat part which connects the two inner side fixing parts arrange | positioned in a major axis direction can be integrally formed in the inner peripheral side of the 1st voice coil 4a. The inner flat part of the first damper 5a connects the two inner fixing parts across the through hole 14 of the magnetic circuit 10 along the long diameter direction, and reinforces the track-shaped bobbin. That is, in the electrodynamic speaker 1 of the present embodiment, the magnetic circuit 10 has the through hole 14, so that the inner peripheral side of the bobbin can be connected along the major axis direction by the inner flat portion of the damper 5. In addition, the first voice coil 4a can be stably supported so as to vibrate.

  On the other hand, in the electrodynamic speaker 1, when an audio current is supplied to the second voice coil 4b, a driving force acts on a linear portion of the second voice coil 4b arranged in the magnetic gap 13c, and the second voice coil 4b is operated. The coil 4b vibrates in the X-axis direction, and the connected second diaphragm 2b also vibrates in the X-axis direction. The second diaphragm 2b is flexibly supported by the second edge 3b that supports the outer peripheral end thereof. Further, the second damper 5b that supports the track-shaped second voice coil 4b so as to vibrate is fixed to the second frame portion 6b at its outer fixing portion. Accordingly, the second voice coil 4b connected to the second diaphragm 2b is greatly displaced in the X-axis direction at a frequency near or below the lowest resonance frequency f0.

  In the electrodynamic speaker 1 of the present embodiment, the second voice coil 4b has one track-shaped linear portion disposed in the linear magnetic gap 13c of the magnetic circuit 10, and the other linear portion is the second diaphragm. It connects with the engagement recessed part of the center part of 2b. In addition, the arc of the second voice coil 4b and the reinforcing plate 43 are connected to the slit of the inner fixed portion of the second damper 5b. In the present embodiment, the two bonded coils 41 and 42 constituting the second voice coil 4b are bonded to the bonded portions (for example, one linear portion of the coil 41 and one linear portion of the coil 42). They are connected in series so that audio signal currents flow in the same direction. Of course, the coils 41 and 42 may be connected in parallel. Further, the tinsel wire (not shown) connected to the second voice coil 4b is electrically connected by soldering a terminal (not shown) fixed to the frame 6 and a lead wire of the second voice coil 4b from the terminal. Then, an audio current is supplied to the second voice coil 4b. However, the tinsel wire may be electrically connected to the terminal by providing a metal eyelet on the second diaphragm 2b.

  When an audio signal current is supplied to the second voice coil 4b by the electrodynamic speaker 1, one linear portion of the second voice coil 4b disposed in the linear magnetic gap 13c of the magnetic circuit 10 is placed in the X-axis direction. Driving force acts. The second voice coil 4b includes the reinforcing plate 43 (not shown) that engages between one linear portion and the other linear portion, thereby reinforcing the coils 41 and 42 and increasing rigidity. ing. The reinforcing plate 43 is made of resin or non-magnetic metal and can be realized with a minimum volume accommodated in the inner space, so that the weight can be reduced and is suitable for the thickness dimension 4t of the second voice coil 4b. It is not necessary to make it larger than the linear magnetic gap size, and a high magnetic flux density can be maintained. The reinforcing plate 43 of the present embodiment is a track-shaped flat plate that can be easily processed, but may be lightened by providing a through hole or a meat stealer. Therefore, it is possible to increase the sound reproduction efficiency and to make the electrodynamic speaker 1 having excellent sound reproduction ability. A driving force acting on a portion (one linear portion of the second voice coil 4b) disposed in the magnetic gap 13c of the magnetic circuit 10 of the second voice coil 4b is connected to the other linear portion of the second voice coil 4b. It is sufficiently transmitted to the second diaphragm 2b. As a result, the electrodynamic speaker 1 using the second voice coil 4b can secure a wide audio reproduction band by increasing the high frequency limit frequency.

  As described above, the first diaphragm 2a is a speaker diaphragm having a larger diaphragm area than the second diaphragm 2b. The first diaphragm 21, which is a large diaphragm, is excellent in reproduction of the mid-low range, and the second diaphragm 22 connected to the second voice coil 4 b including the reinforcing plate 43 has a driving force generated in the second voice coil 4 b. Since it is transmitted directly, it is possible to configure a speaker vibration system that excels in high-frequency range reproduction. Therefore, the electrodynamic speaker 1 including the first diaphragm 2a and the second diaphragm 2b can substantially increase the diaphragm area by about 23% compared to other speakers having the same volume or surface area. The playback sound pressure level of the electrodynamic speaker 1 can be increased. In the case of the present embodiment, the second diaphragm 2b that vibrates in the X-axis direction is a speaker diaphragm having a smaller area than the first diaphragm 2a, and is suitable for high-frequency range reproduction. The radiation directivity characteristic of the first diaphragm 2a that vibrates in the Z-axis direction is such that the second diaphragm 2b assumes this band because the sound pressure level in the high sound range decreases in the X-axis direction, which is a substantially orthogonal direction. Thus, the directivity characteristics of the electrodynamic speaker 1 can be improved.

  The magnetic circuit 10 of the electrodynamic loudspeaker 1 is an external magnetic type in which rod-like magnets 15a and 15b are arranged outside a region to be projected when the track-shaped coil of the first voice coil 4a is viewed in plan from the Z-axis direction. Since the magnets 15a and 15b are magnetized so that the planes connected to the top plate 11 or the pole 12 have different magnetic polarities, the linear magnetic air gaps 13a, 13b, In addition, a magnetic field having a high magnetic flux density is generated in 13c. Since the rod-like magnets 15a and 15b having a strong coercive force are arranged so as to extend in the major axis direction, they are suitable for an elongated speaker such as the electrodynamic speaker 1 of the present invention. If the maximum width of the magnetic circuit 10 can be reduced and its overall height can be reduced, the magnetic circuit 10 can be accommodated in a region formed when the elongated first diaphragm 2a is viewed from the Z-axis direction. This is because the magnetic circuit 10 is contained in a region formed when the second diaphragm 2b is viewed from the X-axis direction. In the magnetic circuit 10, the lengths of the linear portions 11a and 11b along the Y-axis direction, which is the major axis direction, and the magnetic air gaps 13a and 13b including 11c, and 13c are shorter than those of the rod-shaped magnets 15a and 15b. . Therefore, magnetic flux concentrates on the magnetic air gaps 13a and 13b and 13c, and a high magnetic flux density distribution can be obtained even in the thin magnetic circuit 10. Therefore, the highly efficient electrodynamic loudspeaker 1 is realized, including the use of the lightweight first diaphragm 2a and the second diaphragm 2b.

  In addition, in the electrodynamic speaker 1, two movable parts of the first damper 5 a are disposed in the internal spaces 16 a and 16 b of the magnetic circuit 10, respectively, corresponding to the magnetic circuit 10. The two movable parts of the first damper 5a positioned in the major axis direction are substantially fan-shaped, have corrugations, and are portions respectively disposed in the internal spaces 16a and 16b that are not used as magnetic gaps. The two movable parts of the first damper 5a can support the first voice coil 4a so as to vibrate so as not to interfere with the magnetic circuit 10, respectively. Therefore, the electrodynamic speaker 1 can be thinned by reducing the overall height of the magnetic circuit 10 of the electrodynamic speaker so that the entire magnetic circuit 10 is accommodated in the frame 6. Even in the case of an elongated electrodynamic speaker in which the operation of the vibration system is likely to be unstable, the electrodynamic speaker 1 of the present embodiment generates an abnormal noise when the voice coil contacts the magnetic gap of the magnetic circuit, The problem of malfunction can be suppressed.

  6, 7, and 8 are diagrams illustrating the display device 20 including the electrodynamic speaker 1 of the above-described embodiment. Specifically, FIG. 6 is a rear view of the display device 20, and FIG. 7 is a BOB ′ cross-sectional side view of a portion of the display device 20 to which the electrodynamic speaker 1 is attached. These are the perspective views at the time of seeing the display apparatus 20 from front diagonally downward.

  For example, the display device 20 is the display device 20 in which the electrodynamic speaker 1 is attached to the left and right two positions on the back side of the housing 21 (in the direction of arrow B in the figure) so that the first diaphragm 2a is exposed. Then, a thin rectangular flat casing 21 is floated from a mounting surface such as a floor by a stand 22 so that sound radiated from the electrodynamic speaker 1 is directed to the front side of the display device 20 (in the direction of arrow F in the figure). Also trying to reach. A display unit 24 for projecting an image is provided on the front side of the casing 21 of the display device 20, and a frame unit 23 is defined around the display unit 24. The left and right electrodynamic speakers 1 corresponding to the stereo left and right signals are respectively supplied with audio signal currents obtained by power amplification of the stereo left and right signals from amplifiers (not shown) built in the casing 21. Of course, the configuration of the display device 20 is not limited to the illustrated one including the shape of the stand 22.

  In the display device 20 of the present embodiment, when viewed from the front side (in the direction of arrow F in the figure), the electrodynamic speaker 1 is moved to the lower corner of the frame portion 23 of the casing 21 so as not to be exposed. The electric speaker 1 is attached. The electrodynamic speaker 1 of the above-described embodiment is attached so that the first diaphragm 2a and the second diaphragm 2b are exposed on the two surfaces (the back surface and the bottom surface) constituting the lower corner portion of the casing 21, respectively. be able to. That is, the electrodynamic speaker 1 can be attached to the display device so as to emit sound in two directions of the back surface and the bottom surface constituting the corner portion. Therefore, even if there are many mounting conditions such as when it is desired to prevent the electrodynamic speaker 1 from being viewed from the front for design reasons, or when it is desired to reduce the frame portion 23 when viewed from the front, the electrodynamic speaker 1 It is possible to improve the sound reproduction conditions of the type speaker 1.

  For example, when the electrodynamic speaker 1 is attached to the display device 20 so that the diaphragm is not exposed to the front side as in the present embodiment, the first diaphragm 2a is exposed to the back side of the display device 20. Even if attached to the housing 21, the second diaphragm 2a that can vibrate in the lower surface direction (in the direction of arrow D in the figure) that is substantially perpendicular to the first diaphragm 2a is exposed. Therefore, the electrodynamic loudspeaker 1 can prevent the reproduction level of the first and second diaphragms 2a disposed on the back side from being lowered in the middle and high sound range by the other second diaphragm 2b, thereby improving the reproduction sound quality. be able to. As described above, the second diaphragm 2b is a diaphragm suitable for high-frequency range reproduction, and is attached to the lower side surface of the housing 21 so that it easily goes around to the front side due to diffraction of sound waves.

  In this embodiment, the thin electrodynamic speaker 1 is mounted so that the first diaphragm 2a and the second diaphragm are exposed on the two surfaces (the back surface and the bottom surface) constituting the lower corner portion of the housing 21. Although the electrodynamic speaker 1 attached to the display device 20 is attached, the first diaphragm 2a and the second diaphragm 2b are provided on any two surfaces constituting the corner portion of the casing 21 of the display device 20, respectively. What is necessary is just to attach so that it may be exposed. For example, even if the first diaphragm 2a of the electrodynamic speaker 1 is disposed on the back side of the housing 21, the second diaphragm 2b may be disposed on the side surface (or top surface side). Good. Alternatively, when the thickness of the casing 21 of the display device 20 is somewhat large, the first diaphragm 2a of the electrodynamic speaker 1 is disposed on the side surface (or top surface side, bottom surface side) of the casing 21. In this way, the second diaphragm 2b may be arranged on the front side.

  In the above embodiment, even the thin electrodynamic speaker 1 including the first diaphragm 2a that vibrates in the Z-axis direction further includes the second diaphragm 2b that can vibrate in the substantially perpendicular X-axis direction. However, the present invention is not limited to the above embodiment. For example, the magnetic circuit 10 further forms a magnetic air gap in the X-axis direction or the Y-direction to form a vibration system that can vibrate in the X-axis direction or the Y-direction, and vibration that can emit sound in the X-axis direction or the Y-direction. A plate may be further provided. By providing a plurality of diaphragms radiating in different directions and increasing the diaphragm area, the electrodynamic speaker 1 having high efficiency and excellent directivity is realized.

  Further, in the above embodiment, the first voice coil 4a connected to the first diaphragm 2a vibrating in the Z-axis direction is a track-shaped voice coil, and the second voice coil 4a connected to the second diaphragm 2b vibrating in the X-axis direction is used. Although the voice coil 4b is a flat track-shaped coil having a winding axis direction in the Z direction, the present invention is not limited to the above embodiment. The first voice coil 4a may be a voice coil having a round cross section, and the second voice coil 4b may be a track-shaped voice coil including a linear portion having a winding axis direction in the X direction. If the thickness of the second voice coil 4b in the Z direction can be reduced, the thin electrodynamic speaker 1 having the second diaphragm 2b that vibrates in the X-axis direction can be realized. Further, the second voice coil 4b does not necessarily include the reinforcing plate 43 as in the above embodiment.

  The electrodynamic speaker of the present invention can be applied not only as a speaker built in video / audio equipment such as a display but also to a game machine having a cabinet with a built-in speaker for reproducing sound, a game machine such as a slot machine, etc. It is. In addition, the electrodynamic speaker provided with the magnetic circuit for a speaker according to the present invention has a narrow overall width and can realize a speaker system that reproduces sound in a small and thin cabinet. Suitable.

DESCRIPTION OF SYMBOLS 1 Electrodynamic type speaker 2a, 2b 1st diaphragm, 2nd diaphragm 3a, 3b 1st edge, 2nd edge 4a, 4b 1st voice coil, 2nd voice coil 5a, 5b 1st damper, 2nd damper 6 Frame 10 Magnetic circuit 11 Top plate 12 Pole 13a, 13b, 13c Magnetic air gap 14 Through hole 15a, 15b Magnet 16a, 16b Internal space

Claims (7)

A first diaphragm that vibrates in a first axial direction; a first voice coil that is coupled to the first diaphragm; and a second diaphragm that vibrates in a second axial direction that is substantially perpendicular to the first axial direction And a second voice coil connected to the second diaphragm,
A magnet, a first yoke coupled to the bottom surface side of the magnet, and a second yoke coupled to the top surface side of the magnet, wherein the first voice coil is arranged to vibrate in the first axial direction. A first magnetic air gap, and a magnetic circuit having a second magnetic air gap in which the second voice coil is arranged to vibrate in the second axial direction.
The magnetic circuit forms the first magnetic gap between a first side wall portion formed by being cut and raised from a bottom portion of the first yoke and an inner peripheral end portion of the second yoke, and the first yoke The second magnetic gap is formed between a first extending portion formed to extend from the bottom portion to the outer peripheral side and a second extending portion formed to extend to the outer peripheral side of the second yoke. Form,
Electrodynamic type speaker. The first voice coil includes a substantially cylindrical coil formed by winding a round wire or a rectangular wire obliquely with respect to a first winding axis coinciding with the vibration direction and winding it around a bobbin;
The second voice coil includes a flat coil formed by multi-layer winding without shifting a flat wire with respect to a second winding axis substantially orthogonal to the vibration direction,
The first voice coil and the second voice coil are connected in series or in parallel.
The electrodynamic speaker according to claim 1. The first magnetic gap and the second magnetic gap of the magnetic circuit are both linear gaps, and the first voice coil and the second voice coil are respectively the first magnetic gap and the second magnetic gap. Formed in a track shape including a straight line portion arranged in
The electrodynamic speaker according to claim 1 or 2. The first magnetic gap of the magnetic circuit is configured as a pair of linear gaps arranged in parallel, and the pair of linear portions of the track-shaped first voice coil are arranged so as to be able to vibrate. ,
The electrodynamic speaker according to claim 3. A frame coupled to the magnetic circuit;
An outer peripheral end side of the first diaphragm and a first edge connected to the frame;
An outer peripheral end side of the second diaphragm and a second edge connected to the frame;
Further comprising
The electrodynamic speaker according to any one of claims 1 to 4. An inner periphery fixing portion connected to the bobbin of the first voice coil, an outer periphery fixing portion connected to the frame, and a support movable portion formed between the inner periphery fixing portion and the outer periphery fixing portion. A first damper having,
A second inner part fixed to the second voice coil; an outer peripheral fixed part connected to the frame; and a movable support part formed between the inner peripheral fixed part and the outer peripheral fixed part. A damper, and
The electrodynamic speaker according to any one of claims 1 to 5. A display device comprising the electrodynamic speaker according to any one of claims 1 to 6,
A display device in which an electrodynamic speaker is attached so that the first diaphragm and the second diaphragm are exposed on two surfaces constituting a corner portion of a casing of the display device.

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