Patent Grant
10057686
This application is a U.S. national stage application of the PCT International Application No. PCT/JP2015/006006 filed on Dec. 3, 2015, which claims the benefit of foreign priority of Japanese patent application 2014-251640 filed on Dec. 12, 2014, the contents all of which are incorporated herein by reference.
The present disclosure relates to a loudspeaker that can be mounted in various electronic apparatuses, and an electronic apparatus and a mobile body device each including such a loudspeaker.
Conventional loudspeakers typically include a frame, a magnetic circuit having a magnetic gap, a voice coil, a diaphragm, and a center pole. The magnetic circuit includes a yoke, a ring magnet, an annular top plate, and magnetic fluid. The center pole is a columnar projection extending from the center of the yoke.
The magnetic circuit is stored in and coupled to the frame. The outer periphery of the diaphragm is coupled to the frame. The magnet is coupled to the yoke. The top plate is coupled onto the magnet. The center pole penetrates the centers of the magnet and the top plate. The magnetic gap is located between the side surface of the center pole and the inner circumferential surface of the top plate. One end of the voice coil is coupled to the diaphragm and the other end is inserted in the magnetic gap.
In the above configuration, the magnetic fluid is injected between the voice coil and the center pole and also between the voice coil and the top plate.
One example of techniques related to the present application is Patent Literature 1.
PTL 1: Japanese Unexamined Patent Application Publication No. S59-152797
The loudspeaker in accordance with the present disclosure includes a bottom plate, an internal magnet, an internal plate, an external magnetic part (first external magnetic part), a frame, a diaphragm, and a voice coil.
The internal magnet has a first surface, which is coupled to the bottom plate.
The internal plate is coupled to a second surface of the internal magnet on the reverse side from the first surface.
The first external magnetic part is coupled to the bottom plate with the internal plate and a first magnetic gap located therebetween.
The frame is coupled to at least one of the bottom plate and the first external magnetic part.
The diaphragm has an outer peripheral edge, which is supported by the frame.
The voice coil, which is cylindrical, has a first end and a second end opposite to the first end. The first end is coupled to the diaphragm, and the second end is inserted in the first magnetic gap.
The internal plate includes a cutout portion where the internal plate has an outer periphery, which is smaller than the outer periphery of the internal magnet when viewed from the top surface of the internal plate.
Between the voice coil and the internal plate, there are a holding portion holding magnetic fluid and a void part having a void. The holding portion and the void part are adjacent to each other.
The magnetic fluid is held in part of the cutout portion.
In the conventional loudspeaker, the vibration of the diaphragm causes the air in the space surrounded by the diaphragm, the voice coil, and the center pole to flow out or into the space from outside loudspeaker. Therefore, if the voice coil has a large amplitude, the air flowing in and out is likely to scatter the magnetic fluid. The scattering of the magnetic fluid may also be caused when the loudspeaker is accidentally dropped and subjected to an impact force.
The following is a description of the loudspeaker in accordance with the present exemplary embodiment, and an electronic apparatus mounted with the loudspeaker. Prior to describing the loudspeaker, the electronic apparatus will be described as follows. The electronic apparatus, which is mounted with the loudspeaker, is a stationary type such as video devices like TVs and audio devices like mini-components. Since the electronic apparatuses of this type are placed in households, it rarely occurs that the magnetic fluid is subjected to an impact. Therefore, stationary electronic apparatuses are designed primarily to reduce the scattering of the magnetic fluid due to the vibration of the voice coil.
Conventional loudspeakers used as tweeters for the high-frequency sound range is necessary to reduce the input of low-frequency signals. In other words, it is necessary to reduce the scattering of the magnetic fluid by decreasing the amplitude of the voice coil. Meanwhile, in loudspeakers capable of reproducing the entire range, such as full range and woofer loudspeakers, the voice coil has a large amplitude when receiving low frequency sound waves. Therefore, these loudspeakers are designed to reduce the scattering of the magnetic fluid caused by the amplitude of the voice coil.
In the meantime, there is a growing popularity of portable electronic apparatuses such as mobile telephones, smartphones, portable game consoles, and portable navigation devices, which are expected to be small and light.
With the recent popularity of internet delivery, there have been increasing opportunities for the users to watch movies, TV programs, and other moving images on portable electronic apparatuses. Therefore, these devices are expected to reproduce powerful sounds.
Thus, in spite of their smallness, loudspeakers mounted in portable electronic apparatuses are expected to have features, such as high input power resistance to reproduce high sound-pressure-level sound and a wide reproduction frequency range to reproduce low-frequency sound. Hence, loudspeakers mounted in portable electronic apparatuses are expected to reduce the scattering of the magnetic fluid, which is possibly caused by the large amplitude of the voice coil or by an impact when the electronic apparatus is accidentally dropped.
Loudspeaker 21 in accordance with the present exemplary embodiment will now be described with reference to drawings.
The loudspeaker 21 in accordance with the present disclosure includes bottom plate 28, internal magnet 29, internal plate 30, external magnetic parts 22B (including a first external magnetic part), frame 24, diaphragm 25, and voice coil 26.
Internal magnet 29 has a first surface, which is coupled to bottom plate 28.
Internal plate 30 is coupled to a second surface, which is on the reverse side from the first surface of internal magnet 29.
External magnetic parts 22B are coupled to bottom plate 28 with internal plate 30 and magnetic gaps 23A (including a first magnetic gap) located between them.
Frame 24 is coupled to at least one of bottom plate 28 and external magnetic parts 22B.
The outer peripheral edge of diaphragm 25 is supported by frame 24.
Cylindrical voice coil 26 has first end 26A, which is coupled to diaphragm 25 and also has second end 26B, which is opposite to first end 26A and is inserted in magnetic gaps 23A.
Internal plate 30 has cutout portions 31. The outer periphery of internal plate 30 in cutout portions 31 is smaller than that of internal magnet 29 when viewed from the top surface of internal plate 30.
Between voice coil 26 and internal plate 30, there are located holding portions 27A, 27B, and 27C filled with magnetic fluid 27, and void parts 32 with a void. Holding portions 27A, 27B, and 27C are adjacent to void parts 32.
Magnetic fluid 27 is held in part of each of cutout portions 31.
Loudspeaker 21 in accordance with the present disclosure will now be described in detail. Loudspeaker 21 includes magnetic circuit 22, frame 24, diaphragm 25, voice coil 26, and magnetic fluid 27. Magnetic circuit 22 has magnetic gaps 23A. Magnetic fluid 27 is held in holding portions 27A, 27B, and 27C. Holding portions 27B will also be referred to as the trap portions. Magnetic circuit 22 includes bottom plate 28, internal magnetic part 22A, and external magnetic parts 22B. Internal magnetic part 22A includes internal magnet 29 and internal plate 30. Internal magnet 29 includes magnetic poles 29A and 29B, which are opposite in polarity.
Internal plate 30 includes top surface 60, bottom surface 61, side surfaces 30A, and side surfaces 30C. Top surface 60 is opposite to bottom surface 61 (
Side surfaces 30C have side surfaces 30B and side surfaces 30D (
External magnetic parts 22B face at least part of each of side surfaces 30A with magnetic gaps 23A (
The outer peripheral edge of diaphragm 25 is supported by frame 24 (
Cutout portions 31A are located on the boundary between void parts 32 and holding portions 27A. Since side surfaces 30B are located inside the outer peripheral edge of internal magnet 29, magnetic fluid 27 is attracted and held in part of each of cutout portions 31A and 31B by the magnetic force of internal magnet 29 in cutout portions 31A and 31B. As a result, cutout portions 31A and 31B have holding portions 27B (trap portions) in which magnetic fluid 27 is held. The magnetic force of internal magnet 29 keeps the magnetic fluid within holding portions 27B, for example, when loudspeaker 21 is dropped and subjected to an impact force. This reduces the scattering of the magnetic fluid.
The vibration of diaphragm 25 can increase or decrease the volume of the space defined by diaphragm 25, voice coil 26, and internal magnetic part 22A. When diaphragm 25 vibrates in the direction of decreasing the volume of the space, the air in the space flows out through the passage extending between internal magnetic part 22A and the inner side surfaces of voice coil 26. Meanwhile, when diaphragm 25 vibrates in the direction of increasing the volume of the space, the air outside loudspeaker 21 flows into the space though the passage. In this situation, magnetic fluid 27 is likely to scatter in the vicinity of the boundary between holding portions 27A and void part 32A. However, in the configuration in accordance with the present disclosure, the magnetic force of internal magnet 29 in cutout portions 31A keeps magnetic fluid 27 within cutout portion 31A1. This configuration reduces magnetic fluid 27 from infiltrating void parts 32, and also reduces a decrease in the passage sectional area, and hence, an increase in the speed of the air flowing through the passage. As a result, the magnetic fluid is less scattered.
In the present exemplary embodiment, the magnetic fluid is less scattered, and hence, less reduced in amount. As a result, the magnetic flux density in magnetic gaps 23A can be maintained using small-sized internal magnet 29 with a small magnetic force. Thus, loudspeaker 21 has high input power resistance, a wide reproduction frequency range, and other excellent characteristic in spite of its smallness. The input power resistance is also increased because loudspeaker 21 prevents the temperature rise of the voice coil. As a result, loudspeaker 21 has better sound pressure characteristics.
Loudspeaker 21 will now be described in more detail. Loudspeaker 21 preferably includes terminals 33 (
Magnetic fluid 27 will now be described as follows. Fluid 27 should have as high a saturation magnetic flux density as possible so that it can be easily attracted into magnetic gaps 23A by the attractive force of internal magnet 29. This further reduces the scattering of fluid 27. The saturation magnetic flux density of fluid 27 is preferably in the range of 20 mT to 200 mT, inclusive. When it exceeds 200 mT, fluid 27 contains a large amount of magnetic powder and prevents voice coil 26 from vibrating. When it is less than 20 mT, the magnetic attractive force is low, making fluid 27 more likely to scatter. Using fluid 27 with a saturation magnetic flux density in the range of 20 mT to 200 mT, inclusive provides loudspeaker 21 with excellent sound pressure-frequency response.
It is preferable that fluid 27 should have as low a surface tension as possible on the inner side surfaces of voice coil 26 so as to be more wettable to voice coil 26. This increases the area of holding portions 27A in which fluid 27 and voice coil 26 come into contact with each other. As a result, fluid 27 is less scattered.
The clearances between voice coil 26 and internal magnetic part 22A and between second end 26B of voice coil 26 and bottom plate 28 are very small. If having a small surface tension on the inner side surfaces of voice coil 26, fluid 27 may infiltrate these clearances due to the capillary phenomenon. To avoid this happening, it is preferable that a coating agent or adhesive (not shown) should be applied to second end 26B of voice coil 26 excluding side surfaces 230A. The coating agent or adhesive is preferably applied also to the following regions: the side surfaces of internal magnet 29; the top surface of bottom plate 28; the region between internal magnet 29 and internal plate 30; and the top surface of internal plate 30. This configuration prevents fluid 27 from infiltrating small clearances other than holding portions 27A and from flowing onto the top surface of internal plate 30. Examples of the coating agent and adhesive include fluorine-based material. Fluorine-based coating agents and adhesives repel fluid 27 and prevent its flowing out.
If fluid 27 reaches the joint between voice coil 26 and diaphragm 25, fluid 27 may spread further along the joint of voice coil 26 and diaphragm 25 due to the capillary phenomenon. To avoid this happening, the coating agent or adhesive is preferably applied to first end 26A of voice coil 26 excluding side surfaces 230A so that fluid 27 can be prevented from reaching the joint between voice coil 26 and diaphragm 25.
If voice coil 26 is substantially square-shaped when viewed from above, fluid 27 that has reached the four corners of voice coil 26 may creep up the four corners due to the capillary phenomenon and may reach the joint between voice coil 26 and diaphragm 25. In this situation, too, fluid 27 may spread further along the joint between voice coil 26 and diaphragm 25. To prevent fluid 27 from reaching the four corners of voice coil 26, it is preferable that the corners should be coated with the coating agent or adhesive.
The coating agent or adhesive may be applied to surround side surfaces 230A of voice coil 26 instead of being applied to the entire region of voice coil 26 excluding side surfaces 230A.
Magnetic circuit 22 will now be described in detail. External magnetic parts 22B face side surfaces 30A with magnetic gaps 23A located between them. In
In other words, internal magnet 29 has side surface 130A1 (first side surface) and side surface 130A2 (second side surface), which is opposite to and substantially parallel to side surface 130A1. Internal plate 30 has side surface 30A1 (third side surface) substantially parallel to side surface 130A1 and side surface 30A2 (fourth side surface) substantially parallel to side surface 130A2. External magnetic part 22B1 (first external magnetic part) faces side surface 30A1 with magnetic gap 23A1 (first magnetic gap) located between them. External magnetic part 22B2 (second external magnetic part) faces side surface 30A2 with magnetic gap 23A2 (second magnetic gap) located between them. Side surface 130A1 and side surface 130A2 may be collectively referred to as side surfaces 130A.
Internal magnet 29 further has side surface 130D1 (fifth side surface) substantially perpendicular to side surface 130A1 and side surface 130D2 (sixth side surface) which is opposite to and substantially parallel to side surface 130D1. Internal plate 30 has side surface 30D1 (seventh side surface) substantially parallel to side surface 130D1 and side surface 30D2 (eighth side surface) substantially parallel to side surface 130D2. Side surface 130D1 and side surface 130D2 may be collectively referred to as side surfaces 130D.
It is preferable that external magnetic parts 22B should face the entire part of side surfaces 30A, but may alternatively face only part of side surfaces 30A. This configuration increases the magnetic force of magnetic gaps 23A. As shown in
As shown in
Internal plate 30, external plates 35, and bottom plate 28, which are made of magnetic material, preferably have a low magnetoresistance and a high saturation magnetic flux density. Hence, it is preferable that these components should be made of permendur. This configuration increases the magnetic flux density in magnetic gaps 23A, and allows fluid 27 to be held in magnetic gaps 23A with a higher magnetic attractive force. As a result, fluid 27 is less scattered.
As shown in
The magnetic flux of internal magnet 29 is once directed to the air in the region where cutout portions 31 and internal magnet 29 overlap with each other. In general, magnetic fluxes flow from high magnetoresistance to low magnetoresistance. Therefore, the magnetic flux once directed to the air from internal magnet 29 flows toward side surfaces 30B in cutout portions 31. The magnetic flux keeps fluid 27 within the region defined by magnetic pole 29A and side surfaces 30B. This results in the formation of holding portions 27B (trap portions) for fluid 27 as shown in
It is preferable that holding portions 27B (trap portions) for fluid 27 should be coupled to holding portions 27A. This configuration prevents holding portions 27B from being separated from fluid 27 held in holding portions 27A. As a result, fluid 27 in holding portions 27A is less scattered.
The clearance between side surfaces 30A and the side surfaces of internal magnet 29 should be as small as possible, and it is further preferable that side surfaces 30A and the side surfaces of internal magnet 29 should be flush with each other. In this configuration, the distance between internal magnetic part 22A and the inner side surfaces of voice coil 26 can be small in cutout portions 31. This prevents holding portions 27B from being separated from fluid 27 in holding portions 27A.
It is preferable that the distance between side surfaces 30D and the inner side surfaces (side surfaces 230D) of voice coil 26 should be larger than the distance between side surfaces 30A and the inner side surfaces (side surfaces 230A) of voice coil 26. This configuration prevents the area of void parts 32 from being reduced by fluid 27. Void parts 32 are the clearances between side surfaces 30C of internal plate 30 and voice coil 26.
It is preferable that cutout portions 31 should include cutout portions 31A1, 31A2, 31B1, and 31B2 (
This configuration provides void part 32A between side surface 30C1 and the inner side surfaces (side surfaces 230D) of voice coil 26 (
In other words, voice coil 26 includes side surface 230A1 (ninth side surface) substantially parallel to side surface 30A1 (third side surface) of internal plate 30 and side surface 230A2 (tenth side surface) substantially parallel to side surface 30A2 (fourth side surface). Voice coil 26 further includes side surface 230D1 (eleventh side surface) substantially parallel to side surface 30D1 (seventh side surface) of internal plate 30 and side surface 230D2 (twelfth side surface) substantially parallel to side surface 30D2 (eighth side surface). Void part 32A is located between side surface 30D1 of internal plate 30 and side surface 230D1 of voice coil 26. Void part 32B is located between side surface 30D2 of internal plate 30 and side surface 230D2 of voice coil 26.
In
Cutout portions 31 are not limited to two pairs, and may be any number of cutout portions. For example, internal plate 30 may include three or more pairs of cutout portions. It is preferable that these pairs of cutout portions 31 should be located 180 degrees rotationally symmetric about the center of internal plate 30 to make diaphragm 25 generate less rolling action.
It is preferable that loudspeaker 21 should have net 36 (
As shown in
Side surface 30A1 and side surface 30A2 are parallel and opposite to each other. External magnetic parts 22B include external magnetic part 22B1 and external magnetic part 22B2. In this case, internal magnetic part 22A is located between external magnetic parts 22B1 and 22B2. This configuration provides magnetic gaps 23A between side surface 30A1 and external magnetic part 22B1 and between side surface 30A2 and external magnetic part 22B2. This configuration also increases the area in which internal magnetic part 22A and external magnetic parts 22B face each other, thereby increasing the magnetic force supplied to voice coil 26. As a result, loudspeaker 21 has excellent sound pressure level characteristics.
It is preferable that external magnetic part 22B1 should include external magnet 34A and external plate 35A as shown in
It is preferable that cutout portions 31A should be located at the four corners of internal plate 30 (
Each of internal plate 30 and the internal magnet has long sides and short sides. The long sides of internal plate 30 and the long sides of internal magnet 29 are aligned in the same direction. In this case, side surfaces 30A are on the long sides, and side surfaces 30D are on the short sides. In this configuration, side surfaces 30A are larger in length than side surfaces 30D when internal plate 30 is viewed from above. This increases the magnetic flux density in magnetic gaps 23A, thereby reducing the scattering of fluid 27.
It is preferable that internal plate 30 and internal magnet 29 should be substantially equal in the length of the short sides. In this configuration, the long-side side surfaces of internal magnet 29 are aligned with side surfaces 30A of internal plate 30. It is also preferable that side surfaces 30A of internal plate 30 and the long-side side surfaces of internal magnet 29 should be aligned with each other. This configuration prevents holding portions 27B (trap portions) from being separated from fluid 27 held in holding portions 27A. This reduces the distance between magnetic pole 29A and voice coil 26 in cutout portions 31, so that fluid 27 in holding portions 27A can be attracted by the strong magnetic force of magnetic pole 29A. This further prevents holding portions 27B from being separated from fluid 27 held in holding portions 27A.
It is preferable that the four corners of internal magnet 29 should be chamfered when internal plate 30 is viewed from above. The chamfer angle can be, for example, 45 degrees (C-chamfered) to increase the area of the air passage and hence to decrease the speed of the air flowing through the passage. The clearances are large between the corners of internal magnet 29 and the inner side surfaces of voice coil 26, so that the air flows through the clearances at low speed. Since cutout portions 31 are located at the four corners of internal magnet 29, the four corners of internal magnet 29 are in the vicinity of the boundary between void parts 32 and holding portions 27A. This configuration reduces the speed of the air in the vicinity of the boundary between void parts 32 and holding portions 27A. As a result, the scattering of fluid 27 is further reduced. The chamfer angle at the four corners of internal magnet 29 is not limited to 45 degrees (C-chamfered) and may be round-chamfered (R-chamfered).
The following is a description of the various cutout portions.
In magnetic circuit 122, external plates 38A are coupled to external plates 35A and 35B via joint 38B. In loudspeaker 222, external plates 38A are directly coupled to bottom plate 28.
Between internal plate 30 and external plates 38A, there are located magnetic gaps 23B, which are a collective term of magnetic gap 23B1 and magnetic gap 23B2.
External magnetic part 22C1 (third external magnetic part) faces side surface 30D1 with magnetic gap 23B1 (third magnetic gap) located between them. External magnetic part 22C2 (fourth external magnetic part) faces side surface 30D2 with magnetic gap 23B2 (fourth magnetic gap) located between them. Second end 26B of voice coil 26 shown in
In magnetic circuit 122, external plates 38A are preferably coupled to external plates 35A and 35B magnetically and mechanically, and may be coupled directly to these plates 35A and 35B without joint 38B. In this configuration, the magnetic flux is applied to voice coil 26 in magnetic gaps 23B in addition to magnetic gaps 23A. As a result, loudspeaker 21 has excellent sound pressure level characteristics.
It is preferable that joint 38B should be bent at the peripheral edges of external plates 35A and 35B toward bottom plate 28. Alternatively, the peripheral edges of external plates 35A and 35B may be bent toward bottom plate 28. It is also preferable that external plates 38A should be integrated with external plates 35A and 35B. This configuration reduces the number of components, thereby reducing the assembly man hours of magnetic circuit 122.
In loudspeaker 222, external plates 38A are bent at the outer peripheral edge of bottom plate 28 toward diaphragm 25. External plates 38A and bottom plate 28 may be integrated as shown in
External magnetic part 22D1 includes external magnet 34C (third external magnet) and external plate 35C. External magnetic part 22D2 includes external magnet 34D (fourth external magnet) and external plate 35D (
The side surface of external plate 35C faces side surface 30D1, whereas the side surface of external plate 35D faces side surface 30D2. Magnetic gaps 23B are located between the side surface of external plate 35C and side surface 30D1 and between the side surface of external plate 35D and side surface 30D2. External magnet 34C is sandwiched between bottom plate 28 and external plate 35C, whereas external magnet 34D is sandwiched between bottom plate 28 and external plate 35D. External magnets 34C and 34D are magnetically coupled in series with internal magnet 29. In other words, external magnets 34C and 34D are coupled onto bottom plate 28. The magnetic poles of external magnets 34C and 34D are opposite to the magnetic pole of internal magnet 29.
In the above-described configuration, the magnetic fluxes of not only internal magnet 29 but also of external magnets 34C and 34D are applied to magnetic gaps 23B. This increases the amount of the magnetic flux in magnetic gaps 23B, so that loudspeaker 600 has a high sound-pressure level. Internal plate 30 has cutout portions 31, which prevent the area of void parts 32A and 32B from being decreased by fluid 27 even if the magnetic flux is large in magnetic gaps 23B. This reduces the scattering of fluid 27. It is preferable that external magnets 34C and 34D should be located distant from external magnets 34A and 34B. This configuration provides clearances between external magnets 34C and 34A, between external magnets 34C and 34B, between external magnets 34D and 34A, and between external magnets 34D and 34B. Voice coil 26 can be coupled to terminals 33 through these clearances.
The following is a description of airflow in loudspeaker 600.
The minimum distance between external magnet 34A (first external magnet) and external magnet 34C (third external magnet) is referred to as a width W1 (first width). The minimum distance between bottom plate 28 and second end 26B of voice coil 26 is referred to as a height H1. There is an opening A1 (first opening) with the width W1 and the height H1. The product of the width W1 and the height H1 is referred to as an area S1 (first area). In short, the area S1 is the area of the opening A1. For easier understanding, the opening A1 (area S1) is hatched in
The minimum distance between external magnet 34B (second external magnet) and external magnet 34C (third external magnet) is referred to as a width W2 (second width) as shown in
The minimum distance between external magnet 34A (first external magnet) and external magnet 34D (fourth external magnet) is referred to as a width W3 (third width) as shown in
The minimum distance between external magnet 34B (second external magnet) and external magnet 34D (fourth external magnet) is referred to as a width W4 (fourth width) as shown in
In
The total area of void parts 32 when viewed from the top surface of internal plate 30 is referred to as a total area TS2 (second total area). The area of regions in cutout portions 31 where internal magnet 29 is not covered with fluid 27 when viewed from the top surface of internal plate 30 is referred to as a total area TS3 (third total area).
The value obtained by subtracting the total area TS3 (third total area) from the total area TS2 (second total area) is referred to as a total area TS4 (fourth total area). In
The following is a description of a loudspeaker including a non-square-shaped internal magnet.
In circular magnetic circuit 22, internal magnetic part 22A is circular when viewed from above as shown in
In oval magnetic circuit 522B, internal magnetic part 22A is oval when viewed from above as shown in
In
In magnetic circuit 522C including rounded-rectangular internal magnet 29 as shown in
Internal magnet 29 may be circular or substantially square-shaped instead of being rounded-rectangular-shaped when viewed from above. It is, however, preferable that external magnetic parts 22B should be substantially square-shaped. In this case, external plates 35 and external magnets 34 are substantially square-shaped when viewed from above.
External magnetic parts 22B may be not substantially square-shaped, but rounded-rectangular-shaped. In this case, external plates 35 and external magnets 34 may have a rounded-rectangular hole in the center when viewed from above. The center hole may be not rounded-rectangular but substantially square-shaped. In this case, it is preferable that external magnets 34 should be formed of a plurality of magnets.
Electronic apparatus 1001 mounted with loudspeaker 700 will now be described with reference to drawings. Loudspeaker 700 is one of loudspeakers 21, 222, 600, and 602.
Electronic apparatus 1001 includes loudspeaker 700 and amplifier 1002, which supplies loudspeaker 700 with electrical signals. Apparatus 1001 preferably includes cabinet 1003, and can further include display unit 1004. In this configuration, loudspeaker 700, amplifier 1002, and display unit 1004 are stored in cabinet 1003. One example of display unit 1004 is a liquid crystal display device. When electrically coupled to terminals 33, amplifier 1002 supplies electrical signals to loudspeaker 700.
Loudspeaker 700 is mounted in electronic apparatus 1001. Therefore, the scattering of fluid 27 can be avoided even when apparatus 1001 is accidentally dropped or subjected to a strong impact. As a result, loudspeaker 700 maintains its characteristics and hence its sound quality.
Next, mobile body device 2001 mounted with loudspeaker 700 will be described with reference to drawings.
Drive unit 2003 receives the power generated by power generation unit 2002 and moves body 2005. In the case that device 2001 is an automobile, drive unit 2003 includes, for example, tires. Steering unit 2004 is coupled with drive unit 2003 to change the travelling direction of body 2005. Steering unit 2004 can be, for example, a steering wheel.
In the case that device 2001 is an automobile, loudspeaker 700 may be integrated into the front panel or the rear tray of the body, or may alternatively be mounted in body 2005 as part of a car navigation system or a car audio system. Loudspeaker 700 is not necessarily mounted directly in body 2005 as a component of the mobile body device, and can be mounted in electronic apparatus 1001 shown in
According to the above-described configuration, the scattering of fluid 27 is avoided even when mobile body device 2001 is subjected to vibration during transport or to impact due to collision with another mobile body device.
As described above, according to the present disclosure, the cutout portions are located on the boundary between the voids and the holding portions. The internal plate is located inside the outer peripheral edge of the internal magnet when viewed from above. In this configuration, the magnetic force of the internal magnet in the cutout portions keeps the magnetic fluid attracted in the cutout portions. As a result, even if the loudspeaker is subjected to an impact force, the magnetic fluid is held in place by the magnetic force of the internal magnet. Furthermore, the magnetic fluid is prevented from infiltrating the voids, so that the voids are prevented from being clogged with the fluid. This reduces the scattering of the fluid.
The loudspeaker in accordance with the present disclosure, which restricts the scattering of the magnetic fluid, is useful in small portable electronic apparatuses such as mobile telephones and smartphones.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-251640 | Dec 2014 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2015/006006 | 12/3/2015 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2016/092782 | 6/16/2016 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4320263 | Thiele | Mar 1982 | A |
| 4357498 | Tsuchiya | Nov 1982 | A |
| 20070147649 | Takase | Jun 2007 | A1 |
| 20080309440 | Itakura | Dec 2008 | A1 |
| 20140079258 | Fujise et al. | Mar 2014 | A1 |
| 20150016660 | Matsumura et al. | Jan 2015 | A1 |
| Number | Date | Country |
|---|---|---|
| 59-152797 | Aug 1984 | JP |
| 2008-312056 | Dec 2008 | JP |
| 2009171279 | Jul 2009 | JP |
| 2010-258856 | Nov 2010 | JP |
| 2013114872 | Aug 2013 | WO |
| 2014097632 | Jun 2014 | WO |
| Entry |
|---|
| International Search Report of PCT application No. PCT/JP2015/006006 dated Mar. 1, 2016. |
| Number | Date | Country | |
|---|---|---|---|
| 20170280247 A1 | Sep 2017 | US |
