JP2001169386A - Radiation diaphragm and high frequency transducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high frequency transducer with a dome diaphragm of a 2-division elliptic shape that can overcome problems of distortion and a failure point in a prior art even in the case of a dome with a frequency in excess of 30 kHz. SOLUTION: The dome diaphragm has a torus skirt 54 extended therefrom in an integrated form, is connected to a disk plate of the transducer. A voice coil 60 with a cylindrical cross section is directly connected to the skirt 54 in an area very close to a dome 52. The dome 52 is not definite but made of a rigid material such as metal, alloy and metalloid consisting of titanium, aluminum, and boron or their combinations. The dome 52 is formed following in a general expression of an ellipse, (x2/a2)+(y2/b2)=1, where a>b, (a) is a half of a distance of the major axis and (b) is a half of a distance of the minor axis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to dome-type transducers, and more particularly, to high-frequency transducers having elliptical domes for improving mechanical acoustic strength and performance.

[0002]

BACKGROUND OF THE INVENTION In the technical field, loudspeakers are used to generate high audio frequencies. Dome loudspeakers are customarily used in loudspeakers used to generate high audio frequencies. Conventionally, a vibrating dome used as a radiating element in a loudspeaker has been designed to have a hemispherical shape with a truncated end when viewed in cross section and to have a cylindrical portion around as shown in FIG. Was. The dome and the tube may be one part or separate parts adapted to be connected to each other. The tubular portion is connected to a movable electromagnetic coil, and the diaphragm and the coil float in a gap formed by the pole pieces of the permanent magnet and receive a current representing a sound to be reproduced. The magnetic force causes the radiation dome to move back and forth with respect to the listener. When the dome moves forward,
The dome compresses the air in front, and as the dome moves backwards, the dome dilutes the air in front. Compression and dilution produce sound.

[0003] However, at high frequencies the movement of the dome is limited, resulting in failure. According to finite element analysis and laser vibration measurements, the mechano-acoustic design of these prior art domes has a deflection and resonance of 3
It has been shown to be below 0 kHz, resulting in mechanical damage and poor acoustic performance. The resulting damage occurs around the dome, where vibrations are concentrated in the dome loudspeaker. As shown in FIG. 2, the prior art dome structure began to flex around the dome at 22 kHz, resulting in breakage and poor acoustic performance. Since the dome and the voice coil vibrate in a disturbed state due to damage in the surrounding area, the “Q” peak point of the frequency response curve becomes high. As a result of the damage, the sound emitted from the dome of the high-frequency diaphragm becomes hard to hear and is indistinct due to the poor vibration transmitting power of the voice coil.

[0004]

SUMMARY OF THE INVENTION Accordingly, the general objects of the present invention are:
It is to eliminate the disadvantages of the prior art.

In particular, it is an object of the present invention to provide a dome that can operate at high frequencies. Another object of the invention is
It is to provide a dome for a high frequency transducer that maintains mechanical strength and acoustic performance even at high frequencies.

It is yet another object of the present invention to provide a dome for a high frequency transducer that maintains mechanical strength and acoustic performance at frequencies above 30 kHz.

It is another object of the present invention to provide a dome for a high frequency transducer with high rigidity at the outer periphery.

It is another object of the present invention to provide a dome for a high frequency transducer having an integral skirt extending from the dome to provide for a strong outer periphery.

It is yet another object of the present invention to provide a dome for a high frequency transducer, the perimeter of which is circumferential to support the perimeter.

It is another object of the present invention to provide a dome for a high frequency transducer that incorporates a voice coil as an element to strengthen its outer periphery.

Yet another object of the present invention is to provide a dome for a high frequency transducer adapted to function with various magnetic systems used in various loudspeakers.

In accordance with the principles of the present invention, there is provided a unique high frequency transducer that overcomes the problems of the prior art.
A high frequency transducer is understood to be an element that is incorporated into a loudspeaker as is known in the art. The high frequency transducer has a magnet pot, which has an annular rim extending therefrom. The magnet pot and rim have an inner surface and an outer surface, and the disk-shaped magnet is received on the inner surface. A channel is formed between the outer periphery of the magnet and the inner surface of the annular rim.

A disk-shaped magnetic pole is positioned on the magnet. Extending inwardly from the rim is an annular lip which is coplanar with the poles, but defines a non-magnetic annular gap therebetween to provide an outer pole. The magnet is preferably neodymium-iron-boron, but any other material having substantially the same or better magnetic properties may alternatively be used. Annular holders are positioned on and outside the rim and are substantially "L" shaped. The annular holder has at least one cavity extending therethrough for receiving a terminal extending therethrough to the outer connector.

The oval dome has an annular skirt that extends therefrom in an integral and unitary manner at the outer periphery. The skirt is connected to the magnetic pole on the opposite side of the dome. The oval dome is bisected in the axial direction and has a long axis extending from a first side of the skirt directly to the opposite side. The dome has a short axis that extends vertically from the long axis to the top of the dome. An oval dome is constructed according to the following general formula for an ellipse: This general formula is (x ² / a ² ) + (y ² / b ² ) = 1, and a> b. The dome can have various sizes within the range according to the general formula.

The dome and skirt are constructed of a rigid material in one and a unitary manner, and over a high frequency range,
Adds additional strength to the structure. Domes are formed of various materials, such as metals, alloys, metal matrices and metalloids.

A voice coil, preferably having a cylindrical cross section, is wound around the skirt and mounted directly on it. To further enhance the structure, the coil is wound as close as possible to the transition area between the dome and the skirt. An annular peripheral component is mounted directly to the dome at a first outer periphery and its second
Is mounted on the spacer at the outer periphery of the rim, and the spacer is mounted on the rim.

In the configured state, the mechanical strength of the structure is increased even at frequencies above 30 kHz, and the acoustic performance of the high-frequency transducer is significantly improved.

[0018] The above objects and advantages of the invention are exemplary only and should not be construed as limiting the invention. These and other objects of the invention described herein,
Features, aspects and advantages will become more apparent from the following detailed description of embodiments of the invention when read in conjunction with the accompanying drawings and the appended claims.

It should be understood that the drawings are used for illustrative purposes only and do not define the scope of the invention. Also, while the figures show symmetric devices, it should be understood that the same elements can be applied to asymmetric devices.

In the drawings, like reference numbers indicate like elements.

[0021]

DETAILED DESCRIPTION Referring to FIG. 3, an axial cross-sectional view of a high frequency transducer 10 is shown. The high frequency transducer 10 is a structure that is typically incorporated into a loudspeaker device (not shown), as is known in the art. Thus, it should be understood that a low frequency transducer having a magnet structure, a voice coil, and a generally frustoconical diaphragm is incorporated into the high frequency transducer 10 by any means known in the art.

The transducer 10 has a magnet pot 12, which has an annular rim 14 extending therefrom. The magnet pot 12 has a generally cylindrical outer surface 16 and can be adapted to function with any low frequency transducer known in the art. The magnet pot 12 has an inner surface 18 and the rim 14 and the magnet pot 12 define an annular recess. The disc-shaped magnet 20 has a lower surface 22 and an upper surface 24 interconnected by an outer wall 26. Magnet 20 is received in magnet pot 12 such that lower surface 22 is disposed on inner surface 18. The outer wall 26 of the magnet 20 does not contact the inner surface 18 of the rim 14, defining an annular channel 28 therebetween.

The disk pole 30 has a first surface 32 and a second surface 34 interconnected by an outer edge 36. The pole 30 is positioned on the magnet 20 such that the first surface 32 of the pole 30 engages the top surface 24 of the magnet 20. Annular lip 38 extends inwardly from upper portion 40 of rim 14. The pole 30 is maintained in a plane similar to the lip 38 such that the circular outer edge 36 is equidistant from the lip to form an outer pole. The nonmagnetic gap 42 is formed between the outer edge 36 of the magnetic pole 30 and the lip 3 of the magnet pot 12.
8 is defined.

Preferably, the magnet 20 is made of neodymium-iron-
It is formed of boron, which allows the air gap between the poles to have a substantially very high magnetic field strength compared to other available magnetic materials. However, it will be appreciated that magnet 20 may be formed of other materials having substantially similar or better magnetic properties than neodymium-iron-boron. Further, a ceramic magnet assembly may be used and transducer 10 may be adapted to accommodate structures known in the art.

A holder 44 having an annular shape is positioned on the rim 14 of the magnet pot 12. The holder 44 has a vertical portion 46 connected to the outer surface 16 of the rim 14 of the magnet pot 12 and has a horizontal portion 48 connected to the upper portion 40 of the rim 14. The vertical portion 46 has at least one cavity extending axially therein for receiving a terminal 50 extending therefrom to an external connector (not shown).

Referring still to FIG.
Has an annular skirt 54 extending therefrom at the outer periphery. Hem
Reference numeral 54 denotes an end opposite to the dome 52 and a second end of the magnetic pole 30.
It communicates with the surface 34. Referring now further to FIG.
The arm 52 has an elliptical shape when bisected in the axial direction.
Extends from a first side of portion 54 to a surface opposite hem 54
It has a major axis 56 and a minor axis 58 perpendicular thereto.
The elliptical shape has the general formula (x ^Two/ A^Two) + (Y^Two/ B^Two) = 1
A> b. The dome 52 has a general formula
It can have various sizes as long as it follows. Preferred practice
In the range of the example, the ratio of a to b is not less than 1.4 and not more than 2.6.
Below. In a more specific preferred embodiment, a
Ratio to 1.75, where a = 12.727
5 mm and b = 7.789 mm.

The dome 52 and the skirt 54 are preferably
It is configured as an integral part to enhance its structural strength and acoustic performance. The dome 52 may be formed of various rigid materials, and in the preferred embodiment, the dome 52
Is formed of multiple types of metals such as, but not limited to, titanium or aluminum. Dome 44 is also 2
It can be formed of a plurality of alloys consisting of more than one kind of metal or a metal having one or more kinds of non-metals. Alloy 1
The metal matrix composite may include more than one metal and one or more metalloids such as, but not limited to, aluminum and boron. In a preferred embodiment, the metal matrix composite trademark "BORALYN" is used for the dome structure, which is commercially available from Alyn Corporation, Irvine, California, USA. is there.

Referring now further to FIG. 6, a voice coil 60, preferably having a cylindrical cross section, is wound around skirt 54 and connected directly thereto. To further enhance the structure of the dome 52 at high frequencies, the coils 60
Is preferably wound as close as possible to the transition region where the dome 52 extends into the skirt 54. An annular shaped and flexible peripheral component 62 is connected at a first edge 64 to the outer periphery of the dome 52 and at a second edge 66 to the horizontal portion 48 of the holder 44. As a result, the hem 5
4. An annular void 68 is defined by the peripheral part 62 and the horizontal part 48 of the holder 44.

The voice coil 60 is connected to a lead out conductor 70 extending from the dome area. The lead-out conductor 70 is connected to the surrounding part 62 and the holder 4.
4 and extends between them. The lead-out conductor 70 is then connected to the terminal 50 and extends out through a cavity extending from the vertical portion 46 to an external connector (not shown).

Still referring to FIG. 7, again using laser vibration measurements, the mechano-acoustic design of the present invention with an elliptical dome was monitored. When tested at a frequency of 22 kHz, as in experiments with prior art transducers, the deflection and resonance at the periphery of the elliptical dome was significantly reduced compared to the prior art. As a result, no damage occurred, the vibrations of the dome and the voice coil were regular, and the "Q" peak point of the frequency response curve was not high. Also, thanks to the elliptical design, the curvature and deflection moved toward the top of the dome and away from the periphery. As a result, the acoustic and mechanical performance of the elliptical dome was improved even at high frequencies beyond 30 kHz.

Referring now to FIG. 8, frequency response measurements were made to compare the acoustic performance of the prior art dome and the elliptical dome. The "Q" peak point of the prior art dome (designated 81) is high at 22.9 kHz, and the peak of the elliptical dome of the present invention (designated 82) is at this frequency up to a frequency of 32.9 kHz. The peak did not reach such a peak, and the upper operating frequency increased from about 20 kHz to about 30 kHz.

While the above description contains many specifics, it should be understood that they are not intended to limit the scope of the invention, but merely as exemplifications of one preferred embodiment thereof. Many other variations are possible without departing from the essential spirit of the invention. Therefore, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a prior art transducer showing the dome, skirt, coil and surrounding components.

FIG. 2 shows damage at the periphery of the dome structure;
FIG. 2 shows the results of laser scanning of a prior art dome at 2 kHz.

FIG. 3 is a cross-sectional view showing a high-frequency transducer having an elliptical dome.

FIG. 4 is an elevation view of an elliptical dome with an integral skirt having a voice coil thereon.

5 is a cross-sectional view of the elliptical dome and skirt along line 5-5 of FIG.

FIG. 6 is a perspective view showing an elliptical dome including a skirt extending from the dome and a voice coil connected to the skirt.

FIG. 7 is a diagram showing the results of laser scanning of an elliptical dome at 22 kHz, showing that damage at the outer periphery of the dome has been reduced.

FIG. 8 is a graph illustrating the frequency response of an elliptical dome compared to a prior art dome, measuring the acoustic pressure level in units of dB.

[Explanation of symbols]

10 High frequency transducer, 12 Magnet pot, 5
2 Domes, 54 hem, 60 voice coils.

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[Procedure amendment]

[Submission date] January 23, 2001 (2001.1.2)
3)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 3

FIG. 4

FIG. 5

FIG. 6

FIG. 7

FIG. 8

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Philip Jeffrey Ansony, United Kingdom, TI 234 W. R. Kent, Singleton Ashford, Bucksford Lane, 68 (72) Inventor Julian Roger Wright United Kingdom, T.N. 127 El Vikent, Matt Field, Oakfield Road, 29

Claims (20)

[Claims] 1. A radiating diaphragm for use in a high frequency transducer, comprising: a dome and an annular skirt extending therefrom; a voice coil connected to the skirt; and a disc-shaped plate connected to the skirt. And a magnet connected to the plate, and an annular magnet pot receiving the magnet on the opposite side of the plate. 2. The radiating diaphragm according to claim 1, wherein the dome comprises a substantially rigid material. 3. The radiating diaphragm according to claim 2, wherein said rigid material is a metal. 4. The radiating diaphragm according to claim 2, wherein said rigid material is an alloy. 5. The radiating diaphragm according to claim 4, wherein the dome is an alloy including at least boron, titanium and aluminum. 6. The radiating diaphragm according to claim 4, wherein said alloy comprises a metal matrix of at least a metal and a metalloid. 7. The radiating diaphragm according to claim 1, wherein the dome has an elliptical configuration. 8. The radiating diaphragm according to claim 6, wherein said elliptical configuration is bisected along its long axis. 9. The shape of the ellipse is represented by the formula (x ² / a ² ) +
(Y ² / b ² ) = 1, where a is equal to half the length of the long axis, b is equal to half the length of the short axis, and a> b
The radiating diaphragm according to claim 6, wherein 10. The radiation diaphragm according to claim 9, wherein a ratio between the major axis and the minor axis is 1.4 or more and 2.6 or less. 11. The ratio of the major axis to the minor axis is 1.75.
The radiating diaphragm according to claim 9, wherein 12. The radiating diaphragm according to claim 6, wherein said dome is integral with said skirt. 13. The radiating diaphragm according to claim 1, wherein the cross section of the coil is cylindrical. 14. The coil of claim 1, wherein the coil is directly connected to the skirt at a transition region from the dome to the skirt.
3. A radiation diaphragm according to claim 1. 15. A high frequency transducer having a radiating diaphragm, the magnet pot having an annular rim at a periphery thereof, and the magnet pot being held in the magnet pot to define a channel between the magnet and the annular rim. A magnet; a disk-shaped plate positioned on the magnet in the rim; a dome diaphragm communicating with the plate; an annular spacer connected to the wall; and a flexible connection to the dome at a periphery thereof. An annular peripheral component, the annular peripheral component further connected to the annular spacer at another portion of the peripheral portion. 16. The high frequency transducer according to claim 15, wherein the dome has a skirt extending therefrom. 17. The high frequency transducer according to claim 15, wherein a cylindrical coil is directly connected to the skirt in close proximity to the dome. 18. The high frequency transducer according to claim 15, wherein said dome has a bisected elliptical shape. 19. The method according to claim 19, wherein the dome has a formula (x ² / a ² ) + (y
Constructed according to ² / b ²⁾ = 1, which is a> b, the high-frequency transducer according to claim 18. 20. A high-frequency transducer having a radiation diaphragm, comprising: a magnet pot having an annular wall around its periphery; an annular lip extending from a middle of an upper portion of the wall; and the magnet and the annular wall. A first magnet held in the magnet pot to define a channel between the first and second portions, a disc-shaped plate positioned on the magnet on a surface similar to the annular lip, and an integral member extending therefrom. An elliptical dome diaphragm having a typical skirt, the skirt being attached to the plate, the dome including at least a material selected from a metal, an alloy, and a metalloid, and further connected to the wall. A spacer and an annular peripheral component that is flexibly connected to the dome at a periphery thereof, the annular peripheral component further connected to the annular spacer. Is, high frequency transducer.