JP2014003356A - Voice coil, magnetic circuit, speaker, sound playback system and its application device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of a planar speaker with high efficiency, high performance, wide design flexibility, and high practical utility.SOLUTION: A plurality of voice coils in square shapes are arranged in a lattice state. Adjacent sides of the voice coil are to be overlapped. Magnetic poles in square shapes are disposed within the voice coils. A permanent magnet is disposed to each of the magnetic poles so that the adjacent magnetic poles have reversed polarity. Current polarity of the adjacent voice coils are set to reversed polarity to each other and driving force is generated in the same direction for all of the voice coils. The structure can respond to the various sizes and performance requirements by increasing the number of voice coils and magnetic circuits, as required, in a surface direction, or in a plurality of layers.

Description

Throughout the entire sentence including the claims, the content in {} has priority over the content outside {}.
The terms defined in the claims are the same in the specification.

The present invention relates to {ideal flat speaker, its voice coil, its magnetic circuit}.

What is important in a high-efficiency flat speaker is {ensuring driving force} and {securing diaphragm rigidity}.
It is not easy to secure driving force under the condition of a flat surface. Moreover, even if the driving force can be ensured, under the condition of high performance, a light and high rigidity diaphragm with a wide plane has many difficult problems in terms of {material selection and shape design}.
The design of the magnetic circuit of a flat speaker requires a high magnetic flux density when a strong driving force is required. Therefore, it requires the thickness of the magnetic path material as well as the performance of the permanent magnet. There is always a trade-off relationship.

The present invention relates to a speaker structure in which driving force is distributed on a plane. A speaker using electromagnetic force is composed of {a magnetic circuit, a voice coil, and a structural part that supports them}. Speaker performance is designed to make the best use of the resources used within the given cost limits. When trying to improve performance, even if only one factor was focused on, it was necessary to consider the constraints due to other factors, and there was no effective solution to increase the overall performance at once. The present invention dramatically improves the {external dimension design freedom, conversion efficiency} of the speaker as an electroacoustic transducer by combining both the {voice coil structure} and {magnetic circuit structure}. It is something to be made.

The demand for {thinning and high efficiency} can be expressed as the following first, second, and third specific technical issues.
The first problem is high-performance surface drive.
Both {the surface drive in which a uniform driving force is distributed in a planar shape} and {having a highly linear driving range} are made compatible.

The second problem is highly efficient surface driving.
{Having strong driving force in the entire frequency range} and {not increasing the inductance component of the voice coil}.

The third problem is the bending strength of the planar diaphragm.
The acoustic radiation plate has both {having a bending strength that can withstand a strong driving force} and {being lightweight so as not to reduce the conversion efficiency in a high frequency region}.

The above first, second, and third problems must always be solved by including a plurality of factors that are in a trade-off relationship. To that end, the basic problem needs to be solved in order to expand the limit range of the trade-off conditions.

For the first issue,
A combined voice coil is used in which a large number of rectangular cylindrical voice coils are arranged in a grid.
The {coil direction and wiring} of the voice coil are configured so that the polarities of the currents flowing in adjacent voice coils are opposite to each other. Each voice coil is provided with a magnetic pole, and a magnetic circuit is configured so that adjacent magnetic poles have opposite polarities.

For the second issue,
By distributing small magnets, the driving force of each one is small, but the magnetic gap density of each magnetic circuit is efficiently increased, and the yoke uses a thin planar magnetic path. Mutual inductance components between the voice coils are canceled by reversing the current polarities of adjacent voice coils.

For the third issue,
The assembled voice coil arranged in close contact with a large number of rectangular cylindrical voice coil lattices reinforces the bending strength of the diaphragm, which is a major weak point of a flat speaker.

There are the following first to ninth effects.
First, surface driving in which driving force is distributed in a planar shape.
Since the current polarity of adjacent coils and the adjacent magnetic poles have opposite polarities, the force generated by the current flowing through the coils is in the same direction in all coil units. By increasing the number of coil units per unit area, the driving force can be distributed in a planar shape to a practically ideal level. The area and shape of the surface can be freely designed without sacrificing the reproduction characteristics. Since the radiation area of the diaphragm can be increased and the stroke of vibration can be reduced, this method is suitable for thin type. In addition, because the magnetic parts are small, even if the magnetic flux density of the magnetic gap is designed high, the magnetic flux is locally small, so that unnecessary magnetic circuit materials are reduced without sacrificing reproduction performance, and a thin structure Suitable for

Secondly, a strong driving force can be obtained by increasing the density of {coil distribution} and {distribution of strong magnetic flux density region where the coil intersects} over the entire plane.
Furthermore, since the current polarities of the coils corresponding to the adjacent magnetic poles are opposite to each other, {the mutual inductance component between adjacent coil units} is canceled out, and the conversion efficiency in the high frequency region is high.

Third, since the coil length within the same area can be made significantly longer than the circumference of the assembled magnetic circuit, a coil that meets the required specifications by combining parallel connection and series connection of voice coils. The degree of freedom in design is high and the selection range is wide.

Fourth, by reducing the size of the voice coil, increasing the number and increasing the density, the coil length within the same area can be greatly increased, and the energy conversion efficiency from electricity to sound is greatly improved. To do.

Fifth, since the voice coil is dispersed in a planar shape, heat generated by the copper loss of the coil is dispersed, and as a result, the {input power limit range due to local temperature rise} is widened.

Sixth, since the driving force can be surface-distributed, the selection range of the shape of the acoustic radiation surface is greatly expanded without changing the basic design.

Seventh, since the driving force can be distributed in a surface distribution, it is not necessary to increase the bending strength of the diaphragm even if the area of the diaphragm is large. Therefore, when obtaining the same sound pressure, the vibration area can be increased and the vibration amplitude can be reduced. This greatly improves the design freedom of the bass reproduction capability.

Eighth, since the total magnetic flux per unit magnetic pole can be reduced, the planar magnetic path can be designed to be thin. Combined with the effect that the vibration amplitude can be reduced by taking a large area, the degree of freedom in designing a thin external appearance is increased.

Explanatory drawing of one Example of basic structure of this invention (a) C-C 'cross section (b) A-A' cross section (c) B-B 'cross section Fig. 1 Magnetic flux distribution and current direction inside circle (a) Enlarged view of circle 71 in Fig. 1 (b) Enlarged view of circle 72 in Fig. 1 Explanatory drawing of one Example of this invention which provided the 2nd permanent magnet in addition to the basic structure of FIG. FIG. 2 is an explanatory diagram of an embodiment of the present invention in which a magnetic circuit and a set voice coil have a two-story structure in addition to the basic structure of FIG. 1.

First, as shown in FIG. 1 (a), 16 rectangular cylindrical voice coils are assembled in a lattice pattern.
On the other hand, 16 rectangular magnetic poles are arranged, and a lattice-like voice coil is accommodated in a gap between the magnetic poles. Permanent magnets are arranged such that all adjacent magnetic poles have opposite polarities, and the magnetic poles and permanent magnets are arranged on a planar magnetic path. The four corners of the planar magnetic path are bent to provide a magnetic gap between the outer sides of the outer magnetic poles. The winding direction or wiring is determined so that the voice coils adjacent to all the voice coils have opposite polarities. That is, when the current direction of the voice coil surrounding all the N magnetic poles is counterclockwise (right rotation), the current direction of the voice coil surrounding all the S magnetic poles is right rotation (left rotation).
Since both the polarity of the adjacent magnetic poles and the polarity of the current flowing in the voice coil are opposite, the driving forces generated in all the voice coils are in the same direction.

FIG. 1 is composed of 16 {voice coils, magnetic poles and permanent magnets}, but in general, it is configured with an arbitrary number depending on the application and performance.

Second, a permanent magnet is provided on the magnetic pole of FIG. 1 to increase the magnetic flux density of the magnetic gap and obtain further driving force.

Third, a permanent magnet, a magnetic pole, and a voice coil similar to those in FIG. 1 are provided on the magnetic pole in FIG. 1 to obtain further driving force.

Since {edge, damper, bobbin} which is a part of the structure of the speaker is the same as that of a general speaker, description thereof is omitted.

Hereinafter, detailed description using drawings.
FIG. 1 shows an embodiment for explaining the basic structure of the present invention.
X1 to X4 indicate the position of the horizontal axis in the description of the drawing, and Y1 to Y4 indicate the position of the vertical axis in the description of the drawing. For example, the center coordinates of 211 magnetic poles are {X1, Y1},
The center coordinates of the magnetic pole 242 are {X4, Y2}.
FIG. 1 shows a plane in which magnetic poles are {16 voice coils, 16 magnetic poles, 16 permanent magnets, 1 plane yoke, 1 diaphragm} of {vertical 4 rows, horizontal 4 columns}. The structure of the speaker.

FIG. 1A shows a CC ′ cross section of FIG.
FIG.1 (b) shows the AA 'cross section of Fig.1 (a).
FIG.1 (c) shows the BB 'cross section of Fig.1 (a).

111, 121, 141, 142 are voice coils located at coordinates {x1, y1}, {x2, Y1}, {X4, Y1}, {X4, Y2}, respectively.
The {thick line and thick arrow} on the four sides of each coil unit indicate the current polarity of the voice coil in the magnetic gap.
211, 221, 231, 241, 242, and 243 are coordinates {x1, y1}, {x2, Y1}, {X3, Y1}, {X4, Y1}, {X4, Y2}, {X4, Y3}, respectively. Magnetic poles located at the
311, 321, 341, 342, 343 are permanent magnets located at coordinates {x1, y1}, {x2, Y1}, {X4, Y1}, {X4, Y2}, {X4, Y3},
4 is a plane magnetic path,
511, 512, 513, 515 are AA ′ cross-sections of the bobbin of the voice coil,
521, 522, 523, 525 are BB ′ cross-sections of the bobbin of the voice coil,
6 is a diaphragm.
A portion surrounded by circles 71 and 72 is a portion {detailed explanation in an enlarged view of FIG. 2 described later}.
A white circle indicates that the current polarity of the voice coil is facing from the front. A black circle indicates that the current polarity of the voice coil is facing from the front to the front.

Voice coil
It is provided at a position centering on the intersection of the abscissa {X1, X2, X3, X4} and the ordinate {Y1, Y2, Y3, Y4}. The current polarity is determined by {winding direction and wiring} so that the current polarities of adjacent voice coils are opposite to each other.
Adjacent magnetic poles are arranged to have opposite polarities. All poles around the N pole are S poles and all poles around the S pole are N] poles.

The voice coil 221 has a right-handed polarity when viewed from above, and the magnetic pole surrounded by the voice coil is an N pole. When a current is passed in the direction of the arrow, a driving force is generated in the direction of pushing out the diaphragm. The voice coil 211 has a left-handed polarity when viewed from above, and the magnetic pole surrounded by the voice coil is an S pole. When a current is passed in the direction of the arrow, a driving force is generated in the direction of pushing out the diaphragm. Similarly, when the same current is supplied to all voice coils in that direction, all voice coils generate a driving force in the direction of pushing out the diaphragm.

A uniform magnetic field is generated in the magnetic gap between adjacent magnetic poles, and the current flowing through the voice coil produces a uniform driving force throughout the voice coil.

FIG. 2 is an explanatory diagram of the magnetic flux distribution between the magnetic poles of the portions {71 and 72} surrounded by a circle in FIG.
2A shows a portion 71 in FIG. 1, and FIG. 2B shows a portion 72 in FIG.
2 has the same function.
Reference numeral 232 denotes the N magnetic pole of the {X3, Y2} coordinate in FIG.
The S poles {222, 231, 242, 233} surround the four sides.
{241, 242, 243} are magnetic poles of {N, S, N} on coordinates {X4, Y1} {X4, Y2} {X4, Y3}, respectively.
{341, 342, 343} are permanent magnets having coordinates {X4, Y1} {X4, Y2} {X4, Y3}.
A set of {thin line and thin arrow} indicates {magnetic flux and direction of magnetic flux} in the magnetic path.
The {magnetic flux from N to S} viewed from above is nearly parallel between the four sides, but swells out of the gap in the space where the corners of the four magnetic poles gather. The voice coil is a quarter circle in this portion and is almost orthogonal to the magnetic flux, so that this quarter circle portion also generates a driving force without greatly reducing the efficiency.

The {magnetic flux between the magnetic poles of 241 and 242} is generated by a magnetic loop having a {341 and 342 permanent magnet} and a plane magnetic path of 4 as a magnetic path. The magnetic circuit of the present invention is not a magnetic path for guiding {magnetic flux from one large magnet} like a general speaker magnetic circuit, but a magnetic path in which small magnets are dispersed and led to small magnetic poles, The magnetic flux in the magnetic path is small. Since the magnetic path is also dispersed, a magnetic path having a large cross-sectional area is not required. Therefore, it can function with a thin plate-like planar magnetic path, and there is little waste of magnetic circuit material, which is suitable for a thin speaker.

FIG. 3 shows an embodiment of the present invention. This is a technique for further increasing the magnetic flux density of the magnetic gap between the magnetic poles in addition to the basic structure of FIG. 1 and 2 indicate the same function. Reference numerals 3011, 3021, 3031, and 3041 denote second permanent magnets.
The first permanent magnet {311, 321, 331, 341} and the second permanent magnet {3011, 3021, 3031, 3041}
It has the same polarity on the magnetic pole {211, 221, 231, 241} side. By providing the second permanent magnet, the magnetic flux density of the magnetic gap can be increased approximately twice.
This is an effective technique for {thinning and high performance}.

FIG. 4 shows an embodiment of the present invention. FIG. 2 is an explanatory diagram in the case of further increasing the driving force by providing one stage {magnetic gap and voice coil} in addition to the basic structure of FIG. 1.
The same numbers as those in FIGS. 1, 2, and 3 in FIG. 4 indicate the same functions.
2011, 2021, 2031, and 2041 are second magnetic poles,
Since the second voice coil is provided in the two-story structure in addition to the first voice coil described in FIG. 1, the driving force is increased. In FIG. 3, the magnetic flux from the magnetic pole opposite to the first magnetic pole of the second permanent magnet is not used as the driving force, but in FIG. 4, the magnetic flux is concentrated in the magnetic gap of the second magnetic pole, and the use efficiency of the magnetic flux Raise. The method of FIG. 4 can increase the driving force by about 1.5 times compared to the method of FIG.

Further, similarly to FIG. 3, by providing a third permanent magnet on the upper surface of the second magnetic pole, the driving force can be approximately doubled compared to FIG.
Furthermore, driving force can be increased by increasing the hierarchy of voice coils and magnetic circuits.

Claim 1 relates to the structure of the voice coil. The present invention relates to a method for increasing the density of a voice coil that obtains an effective driving force by combining rectangular voice coils.
Claim 2 relates to a magnetic circuit combined with the voice coil. A plane driving system is completed by providing a plane magnetic path common to the magnetic pole and the permanent magnet corresponding to each voice coil.
The third aspect relates to a method for increasing the magnetic flux density of the magnetic gap and further increasing the driving force.
A fourth aspect of the present invention relates to a method for further increasing the driving force by making the voice coil and the magnetic circuit into two layers.
The fifth aspect relates to a method of increasing the magnetic flux density of the magnetic gap in the second layer and further increasing the driving force of the voice coil and the magnetic circuit.
A sixth aspect of the present invention relates to a method for increasing a driving force by using a voice coil and a magnetic circuit in an arbitrary hierarchy.
A seventh aspect of the present invention relates to an application of a speaker as a component defined in the first to sixth aspects to a sound reproducing device or an application device thereof.

X1, X2, X3, X4 Position on the horizontal axis of the drawing.
Y1, Y2, Y3, Y4 Position of the vertical axis in the drawing.
111, 121, 131, 132, 133, 141, 142 Voice coils.
Thick line and thick arrow Voice coil and its current polarity.
Thin line and thin arrow Magnetic flux and its direction.
211, 221, 231, 241, 222, 232, 233, 242, 243
First magnetic pole.
2011, 2021, 2031, 2041 The second magnetic pole.
311, 321, 341, 342, 343 First permanent magnet.
3011, 3021, 3031, 3041 Second permanent magnet.
4 Planar magnetic path.
511, 512, 513, 515, 521, 522, 523, 525, bobbin.
6 Diaphragm.
71, 72 Enlarged area.

Claims (7)

A rectangular cylindrical voice coil is used as a voice coil.
The first feature is that the voice coils are arranged in a lattice pattern on the diaphragm so that the rectangular sides of the plurality of voice coils overlap each other.
With the voice coil placed on the diaphragm, the state seen from the diaphragm side of the voice coil is the top surface,
When the same current is applied to all voice coils,
When viewed from the top, the current direction is counterclockwise counterclockwise and the opposite direction clockwise.
A group in which the current direction is counterclockwise when viewed from above is {left-handed voice coil},
A group in which the direction of current is clockwise when viewed from above is {right-handed voice coil},
With the voice coil placed on the diaphragm, all voice coils next to all left-handed voice coils are right-handed voice coils, and all voice coils next to all right-handed voice coils are left-handed voice coils. The second feature is that
The third feature is that the sides of adjacent voice coils are in close contact with each other.
As a result of the second feature, the fourth feature is that the directions of {the currents flowing through both of the closely attached voice coils} are the same,
A combination of all voice coils is used as a voice coil.
A combined voice coil having the above first, second, third and fourth characteristics or a combined voice coil mounted on a diaphragm.
A quadrangular magnetic material that fits in a rectangular cylindrical space inside one voice coil as defined in claim 1 is used as a magnetic pole.
The fifth feature is that the magnetic poles are arranged so that the magnetic poles are accommodated in each voice coil constituting the assembled voice coil,
The side where adjacent sides of the voice coil are in close contact is defined as the close contact side.
The sixth feature is that all the contact edges fit in the magnetic gap between the magnetic poles.
A seventh feature is that {columnar or flat plate} permanent magnets are arranged on each magnetic pole so that adjacent magnetic poles have opposite polarities,
The permanent magnet is a permanent magnet,
{The combination of permanent magnets and magnetic poles} is {plate-like magnetic material for arranging and arranging corresponding to each voice coil} as a planar magnetic path,
The eighth feature is that the permanent magnet is in close contact with the planar magnetic path,
A structure in which each magnetic pole is magnetically coupled to each permanent magnet through a planar magnetic path is referred to as a {assembled magnetic circuit}.
All sides of the assembled voice coil of claim 1 are inserted into the magnetic gap between adjacent magnetic poles, and {the direction of magnetic flux between the magnetic poles by the magnetized magnetic pole} and {the direction of current flowing through the voice coil} are perpendicular to each other The ninth feature is that the magnetic poles of {assembled magnetic circuit} are arranged so as to intersect,
A speaker having the fifth, sixth, seventh, eighth and ninth characteristics.
The permanent magnet defined in claim 2 is a first permanent magnet,
The tenth feature is that the second permanent magnet is disposed on the surface of the magnetic pole defined in claim 2 on the side opposite to the surface of the first permanent magnet,
The polarity of both the first permanent magnet and the second permanent magnet shall be the same polarity on the magnetic pole side,
Speaker having tenth feature
The magnetic pole defined in claim 2 is a first magnetic pole,
The eleventh feature is that the second magnetic pole is disposed on the side of the {second surface of the second permanent magnet defined in claim 3 opposite to the first magnetic pole},
The assembled voice coil defined in claim 1 is a first assembled voice coil,
In addition to the first voice coil, a twelfth feature is that {second voice coil having the same structure as the first voice coil} is arranged in the magnetic gap between the adjacent second magnetic poles.
A pair of voice coils on the same axis constituting the first voice coil and the second voice coil are configured on the same bobbin.
It is assumed that the current polarity is determined so that the forces generated in all the voice coils constituting the first voice coil and the second voice coil are in the same direction by the same current,
A speaker having eleventh and twelfth characteristics.
A thirteenth feature is that a third permanent magnet is disposed on the {opposite surface of the second permanent magnet} of the second magnetic pole of claim 4;
The polarity on the second magnetic pole side of the third permanent magnet is the same as the polarity of the second permanent magnet,
A speaker having a thirteenth feature.
As defined in claim 4 and claim 5, the structure that produces two driving forces consisting of {first and second} {permanent magnet and magnetic pole and assembled voice coil} is a second floor structure,
The 14th feature is that the second-floor structure is further changed to a third-floor structure, a fourth-floor structure, and an arbitrary hierarchical structure.
Speaker having fourteenth feature
A fifteenth feature having a speaker as defined in claim 2, claim 3, claim 4, claim 5 and claim 6, {sound reproduction device}, and {sound car comprising the sound reproduction device} Television set, radio set, telephone equipment, mobile player}