JP2003169393A - Speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a speaker for use in various sound apparatus in which the efficiency of the speaker is enhanced by employing a highly efficient small magnetic circuit of a leaf tweeter reproducing 20 kHz or above. <P>SOLUTION: The speaker comprises a magnet 27 magnetized in the vertical direction, a bottom yoke 24 bonded to the lower surface of the magnet 27, a plate 26 bonded to the upper surface of the magnet 27, and a magnetic circuit 29 forming a magnetic air gap 28 by means of the plate 26 and the bottom yoke 24 wherein the magnet 27 is wider than the plate 26 and the upper surface of the magnet 27 is exposed at least on the magnetic air gap 28 side. Consequently, the volume of the magnet 27 is enlarged without requiring a huge magnetic circuit 29 and since the flux is concentrated upward, a highly efficient small magnetic circuit of a leaf tweeter can be obtained. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodynamic loudspeaker used in various audio equipments, and particularly to 20k.
The present invention relates to a speaker capable of reproducing a high sound range above Hz.

[0002]

2. Description of the Related Art Usually, a speaker for high-pitched sound reproduction is called a tweeter, and recently, DVD audio and super audio for reproducing a music source of 20 kHz or more have been introduced to improve the sound quality. Reproduction up to 100 kHz is required. Further, along with the miniaturization of the entire audio equipment, all speakers are being miniaturized.

Here, the conventional technique will be described with reference to the structural cross-sectional view of the tweeter shown in FIG.

According to FIG. 1, reference numeral 1 denotes a dome-shaped diaphragm, and the diaphragm 1 has an outer peripheral portion in most cases.
It is held by the frame 3 via a roll-shaped edge 2 integrally formed with the frame.

A voice coil bobbin 4 is fixed to the dome-shaped end of the diaphragm 1, and a voice coil 5 wound under the coil bobbin 4 is fixed.

On the other hand, a yoke 6 is provided inside the frame 3.
A magnetic circuit 9 composed of a magnet 7 and a plate 8 is provided, and the voice coil 5 is suspended in a non-contact manner in a magnetic gap 10 formed between an outer peripheral portion of the plate 8 and an inner peripheral portion of the yoke 6. The voice coil bobbin 4 makes a piston motion by a driving current such as a music signal flowing, the diaphragm 1 vibrates, and a sound wave is emitted.

However, in such a structure, the higher the frequency is, the more the driving force of the voice coil 5 is attenuated by the voice coil bobbin 4, and the diaphragm 1 and the voice coil bobbin 4 are usually fixed by the adhesive, so that the adhesive portion is attenuated. In addition, there were many problems in reproducing high-pitched sound of 20 kHz or higher.

As a means for solving the problem of driving force attenuation in the high range, a so-called leaf tweeter having a modified tweeter structure has been proposed.

A conventional leaf tweeter is shown in FIG. 6 (a).
~ It demonstrates by FIG.6 (d). 6 (a) is a top view of the diaphragm which is the main part, FIG. 6 (b) is a top view of the magnetic circuit which is the main part, FIG. 6 (c) is a sectional view taken along the line AB of FIG. 6 (b), (D)
[Fig. 3] is a structural sectional view of a leaf tweeter. According to the figure,
The diaphragm 20 is composed of the film 20, the pattern coil 21, and the frame 22 for fixing the portion where the coil 21 does not exist, and further the bottom yoke 24 and the outer yoke 2 are provided.
5, a plate 26, a magnet 27, and a magnetic circuit 29 constituted by two magnetic gaps 28 constituted by the outer peripheral surface of the plate 26 and the inner peripheral surface of the outer yoke 25. Here, the diaphragm 23 is arranged so that the pattern coil 21 exists on the upper surface side of the magnetic gap 28, and the diaphragm 23 and the magnetic circuit 29 are fixed by the frame 30. Further, it is general that an insulating cushioning material 31 is inserted between the magnetic circuit 29 and the diaphragm 23.

With the leaf tweeter having such a structure, when an electric input as a music signal is applied to the coil 21, a driving force is generated in the coil 21 integrated with the film 20, so that the driving force of the coil 21 is increased. It is an advantageous tweeter to drive the film 20 to emit sound waves without being attenuated and reproduce sound waves of 20 kHz or more.

[0011]

However, in the above-mentioned leaf tweeter, (1) the width of the magnetic gap 28 needs to be equal to or larger than that of the pattern coil 21, which is several times wider than that of a general tweeter. There is a destiny to become. If the magnetic gap 28 is wide, the magnetic flux density will decrease. Further, in such a structure, since the magnetic flux acting on the coil 21 is above the magnetic gap 28, the magnetic flux in the magnetic gap 28 where the magnetic flux is most concentrated cannot be used, and thus the magnetic circuit 29 is structurally inefficient. (2) Since the reproduced sound pressure as a speaker is proportional to the magnitude of the magnetic flux density of the magnetic air gap 28, it is necessary to enlarge the magnet 27 to secure the sound pressure. Further, enlarging the magnet 27 also enlarges the plate 26 fixed to the upper surface of the magnet 27, and enlarges the bottom yoke 24 and the outer yoke 25, which leads to the enlargement of the magnetic circuit 29 and the miniaturization of recent speakers. It will not fit the trend. There was a problem.

The present invention solves the above-mentioned problems and provides an excellent speaker which can secure a sufficient reproduction sound pressure in spite of a small magnetic circuit.

[0013]

In order to solve the above-mentioned problems, a speaker according to claim 1 of the present invention comprises a magnet magnetized at least in a vertical direction and a bottom yoke fixed to the lower surface of the magnet. A magnetic circuit formed of a flat plate fixed to the upper surface of the magnet and forming a magnetic gap between the plate and the yoke, and a planar diaphragm provided with a pattern coil portion on a resin film, the magnetic gap. In the speaker in which the pattern coil section is arranged above
The width of the magnet is larger than the width of the plate, and the upper surface of the magnet is exposed at least on the magnetic gap side. The width of the magnet is larger than the width of the plate. By making the speaker exposed at least on the side of the magnetic gap, the volume of the magnet can be expanded without enlarging the magnetic circuit, and the magnetic flux can be concentrated upward, so that the magnetic circuit is small and highly efficient. It can be converted.

According to a second aspect of the present invention, a leaf tweeter can be formed by providing the magnetic circuit according to the first aspect with two linear magnetic gaps.

According to a third aspect of the present invention, the distance between the inner sides of the coils arranged at the innermost circumference of the loudspeaker according to the second aspect is smaller than the width of the magnet. The layout is optimized to improve the efficiency of the speaker.

According to a fourth aspect of the present invention, the speaker according to the first aspect is provided with a first magnet and a second magnet of the same shape in parallel on a bottom yoke, and the same shape is formed on the first magnet and the second magnet. A first plate and a second plate are provided, a center pole is provided between the first and second magnets of the bottom yoke, and an inner peripheral surface of one side of each of the first and second plates and the center pole. The present invention is to provide two linear magnetic air gaps of the same shape with the outer peripheral surface of, and to realize a small and highly efficient magnetic circuit by using two magnets in a speaker having two linear magnetic air gaps. .

According to a fifth aspect of the present invention, the distance between the outer sides of the coils arranged at the outermost circumference of the speaker according to the fourth aspect is larger than the distance between the inner peripheral surfaces of the two magnets. , The coil arrangement of the diaphragm is optimized to improve the efficiency of the speaker.

According to a sixth aspect of the present invention, there is provided a bottom yoke having a center pole centered on the speaker according to the first aspect and an annular outer yoke on an outer peripheral portion, and mounted on the bottom yoke. A ring-shaped magnet and a ring-shaped plate, a first magnetic gap between the inner peripheral surface of the plate and the outer peripheral surface of the center pole, and a second magnetic gap between the outer peripheral surface of the plate and the inner peripheral surface of the outer yoke. By adopting the concentric configuration, it is possible to provide a circular speaker in which the area of the diaphragm is increased and which can be configured with a small magnetic circuit.

According to a seventh aspect of the present invention, in the loudspeaker according to the sixth aspect, the outer diameter of the first magnetic gap between the outer sides of the coils arranged at the outermost periphery is larger than the inner diameter of the magnet. The inner diameter of the innermost coil of the second magnetic gap is set smaller than the outer diameter of the magnet, and the coil arrangement of the diaphragm is optimized to improve the efficiency of the speaker. It is a thing.

According to an eighth aspect of the present invention, the speaker according to the first aspect is provided with a bottom yoke having an annular center pole, and a cylindrical first pole mounted on the inner circumference of the center pole. A magnet, a ring-shaped second magnet mounted on the outer circumference of the center pole, a disc-shaped first plate mounted on the first magnet, and a ring-shaped second magnet mounted on the second magnet. And an inner peripheral surface of the center pole, respectively.
Magnetic gap is formed, and the second magnetic gap is formed concentrically with the inner peripheral surface of the second plate and the outer peripheral surface of the center pole. It is possible to provide a loudspeaker with a large magnetic circuit and two driving parts for the diaphragm.

According to a ninth aspect of the present invention, in the speaker according to the eighth aspect, the inner diameter between the inner sides of the coils arranged at the innermost circumference in the first magnetic gap is the outer diameter of the first magnet. In the second magnetic gap, the outer diameter of the outermost coil arranged in the outermost circumference is larger than the inner diameter of the second magnet, and the coil arrangement of the diaphragm is optimized.
This is intended to improve the efficiency of the speaker.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a speaker of the present invention will be described below with reference to FIGS. 1 (a) to 4 (c).

In the description, the same parts as those in the prior art will be designated by the same reference numerals, and the description will be omitted.

(Embodiment 1) An embodiment of the speaker of the present invention will be described with reference to the leaf tweeters of FIGS. 1 (a) to 1 (d). FIG. 1A is a top view of a diaphragm, which is a main part,
2B is a top view of the magnetic circuit, which is the main part, FIG. 1C is a cross-sectional view taken along the line AB of FIG. 1B, and FIG. 1D is a structural cross-sectional view of the speaker.

The present embodiment explains Claims 1, 2 and 3.

According to the figure, the diaphragm 23 is the film 20.
And a pattern coil 21, and a bottom yoke 24 which is composed of a frame 22 for fixing a portion where the coil 21 does not exist and which is further provided with an outer yoke 25, and a vertically magnetized magnet 27 mounted thereon. A magnetic circuit 29 having two magnetic air gaps 28 formed by the plate 26 mounted on the plate 26 and the outer peripheral surface of the plate 26 and the inner peripheral surface of the outer yoke 25 is provided.

Here, the vibration plate 23 is arranged so that the pattern coil 21 exists on the upper surface side of the magnetic gap 28, and the vibration plate 23 and the magnetic circuit 29 are fixed by the frame 30. In addition, an insulating cushioning material 31 is provided between the magnetic circuit 29 and the diaphragm 23.
Have been inserted.

The difference from the prior art is that the width of the magnet 27 is larger than that of the plate 26.

Up to now, in the case of a normal leaf tweeter,
This is considered as an extension of the magnetic circuit of a typical tweeter (see FIG. 5), and in order to concentrate the magnetic flux in the magnetic gap 28, at least the plate 26 having the same width as the magnet 27 is fixed and the magnetic gap 28 of the outer yoke 25 is fixed. Make the side shape convex, and The magnetic flux was concentrated in the magnetic gap 28. 2. A magnetic saturation state was created in the outer yoke 25, and the magnetic flux was scattered upward as much as possible. However, the magnetic flux from the magnet 27 could not be efficiently gathered above the magnetic gap 28 where the coil 21 exists because the magnetic flux is scattered downward.

With the configuration of this embodiment, (1) There are two magnetic paths of the magnetic flux emitted from the magnet 27 on the upper surface of the magnet 27. That is, in the portion where the plate 26 is present, a magnetic path is formed in which the magnetic flux emitted from the magnet 27 passes through the plate 26 and flows out to the inner peripheral surface and the upper surface of the outer yoke 25. On the other hand, the magnetic flux from the exposed portion where the plate 26 does not exist is emitted upward from the magnetization direction and becomes a magnetic path that flows out to the inner peripheral surface and the upper surface of the outer yoke 25. Therefore, the magnetic flux is concentrated on the upper side of the magnetic air gap 28 as compared with the conventional magnetic circuit for leaf tweeter.
The magnetic flux density in the coil 21 arranged above is increased, and the efficiency as a speaker is improved. (2) Further, the plate 26 can be made thin, and by making it thin, the magnetic flux can be emitted to the upper side by utilizing the magnetic saturation of the plate 26 (unlike the conventional case, it is not emitted to the lower side).
The magnetic flux density in the coil 21 arranged on the magnetic gap 28 is increased, and the efficiency as a speaker is improved. (3) It is not necessary to enlarge the entire magnetic circuit 29 even if the width of the magnet 27 is enlarged. Therefore, a small and powerful magnetic circuit can be obtained. (4) Even if the same magnet 27 as the conventional one is used, the plate 2
By making the width of 6 smaller than that of the magnet 27, the magnetic circuit 28 can be strengthened for the above reason. (5) The shape of the outer yoke 25 on the side of the magnetic gap 28 does not need to be convex, so that the bottom yoke 24 and the outer yoke 25 are machined, the cost of parts is reduced, and the total height of the magnetic circuit 29 is reduced. There is an advantage.

Further, in the leaf tweeter, the amplitude amount is small, and even if the thin plate 26 is used, the vibrating plate 23 does not have the magnet 27.
Since it does not collide with the upper surface of the coil 21, the distance between the insides of the coils 21 arranged in the innermost circumference is made smaller than the width of the magnet 27, as shown in the figure, so that the coil 21 is kept within the limited magnetic gap 28. A large number are arranged, and the wire length of coil 21 and coil 21
The driving force, which is determined by the product of the magnetic flux density exposed to, can be taken out to a large extent, and sufficient efficiency improvement as a speaker can be realized.

(Embodiment 2) Another embodiment of the loudspeaker of the present invention will be described mainly with reference to claims 4 and 5 by the leaf tweeters of FIGS. 2 (a) to 2 (c). The same parts as those in the first embodiment are designated by the same reference numerals, and the description will be omitted.

FIG. 2 (a) is a top view of a magnetic circuit which is a main part of another embodiment of the present invention, and FIG. 2 (b) is A- of FIG.
A sectional view B and a sectional view (c) of the drawing show a structural sectional view of the leaf tweeter. The same diaphragm as that of the first embodiment is used.

According to the figure, the difference from the first embodiment is the shape of the magnetic circuit 29a. Two magnets 27a magnetized in the same vertical direction are used, the bottom yoke 24 and the plate 26a are fixed to the upper and lower surfaces of the magnet 27a, and the outer peripheral surface of the center pole 25a provided at the center of the bottom plate 24 and the plate 26a. A magnetic gap 28a is formed with the inner peripheral surface.

With this structure, there are two magnetic paths of the magnetic flux emitted from the magnet 27a on the upper surface of the magnet 27a. That is, in the portion where the plate 26a exists, the magnetic flux emitted from the magnet 27a is absorbed by the plate 26a.
A magnetic path that passes through the inside of a and flows out to the inner peripheral surface and the upper surface of the center pole 25a is formed. Meanwhile, the plate 26
The magnetic flux from the exposed portion where a does not exist is emitted upward in the magnetizing direction and forms a magnetic path that flows out to the inner peripheral surface and the upper surface of the center pole 25a. Therefore, the magnetic flux concentrates on the upper side of the magnetic gap 28a, and the magnetic gap 2
The magnetic flux density in the coil 21 arranged on 8a is increased,
The efficiency as a speaker is improved.

By constructing a stronger magnetic circuit 29a for leaf tweeter by using two magnets 27a, a small and highly efficient magnetic circuit can be constructed as in the first embodiment.

Further, as shown in FIG. 2C, the distance between the outer sides of the coil 21 arranged on the outermost circumference is two magnets 27.
By using the diaphragm 23 that is larger than the distance between the inner peripheral surfaces of a, it is possible to effectively arrange a large number of coils 21 in the limited magnetic gap 28a. Therefore, as in the first embodiment, the efficiency of the speaker is improved. realizable.

(Embodiment 3) Another embodiment of the speaker of the present invention will be described mainly with reference to claims 6 and 7 with reference to FIGS. 3 (a) to 3 (d). Note that this embodiment is a circular speaker, and although the embodiment is different from those of the first and second embodiments, the same functional parts will be described with the same numbers for convenience.

FIG. 3A is a top view of the diaphragm, which is the main part,
FIG. 3B is a top view of a magnetic circuit, which is a main part, and FIG.
3B is a sectional view taken along the line AB of FIG. 3B, and FIG. 3D is a structural sectional view of a leaf tweeter that is a speaker.

According to the figure, the difference from the previous embodiments is that the diaphragm 23 and the magnetic circuit 29 are circular in shape, and the diaphragm 23 is divided into two vibrating parts.
In addition, there are two magnetic air gaps 28.

The present embodiment will be described focusing on the above differences.

Since the efficiency of the speaker is proportional to the area of the diaphragm 23, it is desirable to have a large vibration area. However, in the leaf tweeter, when the area of the diaphragm 23 is increased in the conventional structure and the above-described embodiments, the magnetic air gap 28 is inevitably expanded. When the magnetic gap 28 expands, the magnetic resistance in the magnetic path, which is the path of the magnetic flux, increases, so the magnetic flux density decreases, and the efficiency of the speaker decreases.

Therefore, since the width of the magnetic gap 28 is not expanded while the area of the diaphragm 23 is increased, the magnetic circuit 29 has two magnetic gaps as shown in FIGS. 3 (a) to 3 (d). With the configuration, the width of the magnet 27 is made wider than that of the plate 26 to further improve the efficiency.

With the configuration of the present invention, the magnet 2 is provided for both the magnetic gap 28 on the center side and the magnetic gap 28 on the outer side.
On the upper surface of 7, there are two magnetic paths of the magnetic flux emitted from the magnet 27, that is, four magnetic paths. First, with respect to the magnetic gap 28 on the center side, in the portion where the plate 26 exists, the magnetic flux emitted from the magnet 27 passes through the plate 26 and flows out to the inner peripheral surface and the upper surface of the center pole 25a. It is formed. The magnetic flux from the exposed portion where the plate 26 does not exist is emitted above the magnetization direction, and the center pole 25a
It becomes a magnetic path that flows out to the inner peripheral surface and the upper surface.

Next, with respect to the outer magnetic gap 28, the magnetic flux emitted from the magnet 27 at the portion where the plate 26 exists passes through the plate 26 and flows out to the inner peripheral surface and the upper surface of the outer yoke 25. A magnetic path is formed. The magnetic flux from the exposed portion where the plate 26 does not exist is emitted upward in the magnetization direction, and the outer yoke 25a
It becomes a magnetic path that flows out to the inner peripheral surface and the upper surface.

Therefore, the magnetic flux concentrates on the upper side of the magnetic air gap 28, and the magnetic flux in the coil 21 printed on the diaphragm 23 divided into two parts arranged on the two magnetic air gaps 28, respectively. Since the density can be effectively increased, the efficiency as a speaker is improved.

Further, as shown in the figure, the outer diameter of the coil 21 arranged at the outermost periphery in the magnetic gap 28 on the center side is larger than the inner diameter of the magnet 27, and the outer magnetic gap 2 is formed.
By setting the inner diameter between the inner sides of the coils 21 arranged at the innermost circumference in FIG. 8 to be smaller than the outer diameter of the magnets 27, a large number of coils 21 can be effectively arranged in the limited magnetic gap 28. Therefore, as in the above-described embodiments, sufficient efficiency improvement as a speaker can be realized.

(Embodiment 4) Another embodiment of the speaker of the present invention will be described with reference to claims 8 and 9 mainly by the leaf tweeters of FIGS. 4 (a) to 4 (c). Similar to the third embodiment, the same parts as those in the first embodiment will be described with the same reference numerals.

FIG. 4A is a top view of a magnetic circuit, which is a main part, FIG. 4B is a sectional view taken along the line AB of FIG. 4A, and FIG. 4C is a structural sectional view of a leaf tweeter which is a speaker. Is. The same diaphragm as that of the third embodiment is used as the diaphragm.

The difference from the third embodiment is that the magnetic circuit 29 is used.
Is the structure of. The two magnets 27b are used to effectively increase the magnetic flux density of the two magnetic gaps 28.

The present embodiment will be described focusing on the above differences. Disc-shaped and annular magnets 27b magnetized in the same vertical direction are used, bottom yokes 24 are fixed to the lower surfaces of these two magnets 27b, and disc-shaped and annular plates 26b are respectively attached to the upper surfaces of the magnets 27b. To fix. Here, the diameter of the disc-shaped magnet 27b is equal to that of the disc-shaped plate 26.
b, the inner diameter of the annular magnet 27b is set smaller than that of the annular plate.
7b has a part of its upper surface exposed, and the bottom yoke 2
A magnetic gap 28b is formed on the center side of the magnetic circuit 29 by the inner peripheral surface of the annular center pole 25a and the outer peripheral surface of the disk-shaped plate 26b provided in FIG.
The outer peripheral surface of a and the inner peripheral surface of the annular plate 26b form another magnetic gap 28b outside the magnetic circuit 29.

With this configuration, the magnetic gap 2 on the center side is
The magnetic path of the magnetic flux supplied from the disk-shaped magnet 27b arranged on the center side with respect to 8b is considered to be divided into two, and the annular magnet 27 arranged on the outer side with respect to the magnetic gap 28 on the outer side.
The magnetic path of the magnetic flux supplied from b can also be considered as being divided into two. First, with respect to the magnetic gap 28b on the center side, the magnetic flux emitted from the disc-shaped magnet 27b at the portion where the disc-shaped plate 26b exists is the plate 26.
A magnetic path that passes through the inside of b and flows out to the inner peripheral surface and the upper surface of the center pole 25a is formed. The magnetic flux from the exposed portion where the disk-shaped plate 26b does not exist is emitted upward from the magnetization direction and becomes a magnetic path that flows out to the inner peripheral surface and the upper surface of the center pole 25a.

Next, with respect to the outer magnetic gap 28b, the magnetic flux emitted from the magnet 27b passes through the plate 26b at the portion where the annular plate 26b exists, and flows out to the outer peripheral surface and the upper surface of the center pole 25a. A magnetic path is formed. The magnetic flux from the exposed portion where the annular plate 26 does not exist is emitted above the magnetizing direction and becomes a magnetic path that flows out to the outer peripheral surface and the upper surface of the center pole 25a.

Therefore, the magnetic flux concentrates on the upper side of the magnetic air gap 28b, and the magnetic flux in the coil 21 printed on the two divided diaphragms 23 arranged on the two magnetic air gaps 28b. Since the density can be effectively increased, the efficiency as a speaker is improved.

Further, as shown in FIGS. 3 (a) to 3 (c), the inner diameter of the coil 21 arranged at the innermost circumference in the magnetic gap 28b on the center side is outside the disk-shaped magnet 27b. The outer diameter of the coil 21, which is smaller than the diameter and is located on the outermost periphery in the outer magnetic gap 28b, has an annular outer diameter.
Since a large number of coils 21 can be effectively arranged in the limited magnetic gap 28b by using the diaphragm 23 having a diameter larger than the inner diameter of the speaker 23, sufficient efficiency improvement as a speaker is realized as in the previous embodiments. it can.

It should be noted that the frame 31 and the like excluding the magnetic circuit 29 shown in the above-described embodiments have not been directly related to the miniaturization and high efficiency of the magnetic circuit 29, and thus only an example has been shown. Good.

Further, in the third and fourth embodiments, the magnetic circuit 29 and the diaphragm 23 have been illustrated and described as circular, but they may be rectangular, for example, which does not impair the gist of the present invention. There is also nothing.

[0058]

As described above, the speaker of the present invention includes a magnet magnetized in the vertical direction, a bottom yoke fixed to the lower surface of the magnet, a flat plate fixed to the upper surface of the magnet, and a plate. In the magnetic circuit where the magnetic gap is formed by the yoke and the yoke, the width of the magnet is set to be larger than the width of the plate, and the upper surface of the magnet is exposed at least on the magnetic gap side. The efficiency of a small leaf tweeter can be improved.

[Brief description of drawings]

FIG. 1A is a top view of a diaphragm that is a main part of an embodiment of a speaker of the present invention. FIG. 1B is a top view of a magnetic circuit that is the main part. Figure (d) Sectional view

2A is a top view of a magnetic circuit, which is a main part of another embodiment of the present invention, FIG. 2B is a sectional view taken along line AB of FIG. 2A, and FIG.

FIG. 3A is a top view of a diaphragm that is a main part of another embodiment of the speaker, FIG. 3B is a top view of a magnetic circuit that is the main part, and FIG. 3C is a cross-sectional view taken along line AB of FIG. (D) Same sectional view

4A is a top view of a magnetic circuit that is a main part of another embodiment of the speaker, FIG. 4B is a cross-sectional view taken along line AB of FIG. 4A, and FIG.

FIG. 5 is a cross-sectional view of a conventional tweeter.

FIG. 6A is a top view of a diaphragm that is a main part of a leaf tweeter that is another structure of the conventional tweeter. FIG. 6B is a top view of a magnetic circuit that is the main part. Section B (d) Sectional view

[Explanation of symbols]

20 films 21 coils 22 frames 23 diaphragm 24 Bottom yoke 25 outer yoke 25a center pole 26,26a, 26b plate 27,27a, 27b Magnet 28, 28a Magnetic air gap 29, 29a Magnetic circuit 30 frames 31 Insulation cushioning material

Continued front page    (72) Inventor Keiji Ishikawa             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5D012 BB04 FA00

Claims (9)

[Claims] 1. A magnet formed between at least a magnet magnetized in a vertical direction, a bottom yoke fixed to a lower surface of the magnet, and a flat plate fixed to an upper surface of the magnet. In a speaker in which a magnetic circuit that forms an air gap and a planar diaphragm provided with a pattern coil portion on a resin film are arranged above the magnetic air gap, the width of the magnet is larger than the width of the plate. A speaker configured such that an upper surface of the magnet is exposed at least on the magnetic gap side. 2. The speaker according to claim 1, wherein an outer yoke is provided on a side surface of the bottom yoke, and a linear magnetic gap is formed between an outer peripheral surface of the plate and an inner peripheral surface of the outer yoke. 3. The speaker according to claim 2, wherein the distance between the inner sides of the coils arranged at the innermost circumference is smaller than the width of the magnet. 4. A first magnet and a second magnet having the same shape are provided in parallel on a bottom yoke, and a first plate and a second plate having the same shape are provided on the first magnet and the second magnet, respectively. A center pole is provided between the first magnet and the second magnet, and two linear magnetic air gaps having the same shape are provided on the inner peripheral surface of one side of each of the first and second plates and the outer peripheral surface of the center pole. The speaker according to claim 1. 5. The distance between the outer sides of the coils arranged on the outermost periphery is larger than the distance between the inner peripheral surfaces of the two magnets.
The speaker described in. 6. A bottom yoke having a center pole in the center and an annular outer yoke on the outer peripheral portion, an annular magnet and an annular plate mounted on the bottom yoke,
The inner peripheral surface of the plate and the outer peripheral surface of the center pole
2. The speaker according to claim 1, wherein the magnetic air gap is formed by the outer peripheral surface of the plate and the inner peripheral surface of the outer yoke, and the second magnetic air gap is formed concentrically. 7. The inner diameter between the outer sides of the coils arranged on the outermost circumference in the first magnetic gap is larger than the inner diameter of the magnet, and the inner diameter between the inner sides of the coils arranged on the innermost circumference in the second magnetic gap. Is smaller than the outer diameter of the magnet. 8. A bottom yoke having an annular center pole, a cylindrical first magnet mounted on the inner circumference of the center pole, and an annular second magnet mounted on the outer circumference of the center pole. , A disc-shaped first plate mounted on the first magnet and an annular second plate mounted on the second magnet, and the outer peripheral surface of the first plate and the outer surface of the first plate, respectively. The first magnetic gap is formed with the inner peripheral surface of the center pole, and the second magnetic gap is formed concentrically with the inner peripheral surface of the second plate and the outer peripheral surface of the center pole. The described speaker. 9. An inner diameter between inner sides of coils arranged on the innermost circumference in the first magnetic gap is smaller than an outer diameter of the first magnet, and outer sides of coils arranged on the outermost circumference in the second magnetic gap. The speaker according to claim 8, wherein the outer diameter between the two is larger than the inner diameter of the second magnet.