WO2018225180A1

WO2018225180A1 - Electroacoustic transducer

Info

Publication number: WO2018225180A1
Application number: PCT/JP2017/021128
Authority: WO
Inventors: 賢太田中
Original assignee: 賢太田中
Priority date: 2017-06-07
Filing date: 2017-06-07
Publication date: 2018-12-13

Abstract

[Problem] To enable high-quality sound reproduction in an electroacoustic transducer, particularly in a low sound range. [Solution] A drive magnet 17 is secured inside a yoke frame 15 having a flange part 15b, and a vibration film 25 facing the drive magnet is secured to the tip part 15c of the flange part 15b. A voice coil 27 is secured to the vibration film 25 so as to surround a central region. Lead lines 27a from both ends of the voice coil 27 are brought out from one location. An outer peripheral region 25b of the vibration film 25 around the vicinity of the voice coil 27 forms a sealed space E with the flange part 15c. A communication hole 15f is formed in the flange part 15b communicating between the sealed space E and the outside in the vicinity of the position at which the lead lines 27a are brought out.

Description

Electroacoustic transducer

The present invention relates to an electroacoustic transducer, and more particularly, to an improvement in a speaker device such as an earphone or a headphone worn on a user's ear or head, and an electroacoustic transducer that can be used as a microphone.

As a speaker device to be worn on the user's ear, for example, there is a configuration as shown in FIG.

In this configuration, a cylindrical drive magnet 3 is fixed to the inner bottom of a cup-shaped magnetic yoke frame 1, a ring-shaped pole piece 5 is stacked on the drive magnet 3, and a ring is attached to the outer bottom of the yoke frame 1. The circuit board 7 is overlapped, and the yoke frame 1, the drive magnet 3, the pole piece 5 and the circuit board 7 are caulked through a tubular fitting 9 to integrate them.

In addition, an annular flange portion 1a that is bent so as to protrude outward is integrally formed at the tip of the cylindrical portion of the yoke frame 1, and the thin vibrating membrane 11 faces the pole piece 5 with a gap therebetween. Is fixed to the tip of the flange portion 1a.

Further, a voice coil 13 in which a thin insulated conductor is formed in a cylindrical shape is fixed to the central portion of the diaphragm 11 on the yoke frame side, and the voice coil 13 is annularly formed between the outer periphery of the pole piece 5 and the cylindrical portion of the yoke frame 1. Inserted into the gap, both end lead wires 13a of the voice coil 13 are connected to the circuit board 7 through the hollow portion 9a of the fitting 9. The hollow portion of the eyelet 9 is closed.

Moreover, the flange portion 1a and the outer peripheral region from the vicinity of the root of the voice coil 13 in the diaphragm 11 form a sealed space.

Reference numeral 1b in FIG. 9 is a small braking hole formed at the bottom of the yoke frame 1 and communicating with the outside. By appropriately selecting the inner diameter of the small braking hole 1b, the sound quality characteristics of the speaker device can be adjusted. Met.

In such a speaker device, when the audio signal supplied to the circuit board 7 is applied to the voice coil 13 via the lead wires 13a, the vibration film 11 is vibrated by the audio signal to generate drive sound.

In the speaker device as an actual product, the yoke frame 1 is housed in a main body case (not shown) and ear chips (ear pads, earpieces) (not shown) are fitted into the main body case, for example, into an ear canal insertion (canal) type. Composed.

Such a speaker device is not shown, but the main body case main body is placed in such a manner that the diaphragm 11 is brought close to the concha of the concha, which is surrounded by the user's tragus, antipods and concha. The ear tip is elastically brought into contact with the inner wall of the ear canal (not shown) extending from the concha cavity to the eardrum (not shown) while being inserted.

Incidentally, as a known example of the earphone, there is JP 2010-283629 (Patent Document 1), and as a known example of the speaker device, there is JP 6-178390 (Patent Document 2).

JP 2010-283629 A JP-A-6-178390

However, in the above-described speaker device, as shown in FIGS. 10A and 10B, both end lead wires 13 a are led out from one base of the voice coil 13 to the inner space, so that an audio signal is applied to the both end lead wires 13 a. When the voice coil 13 is oscillated and displaced, the following effects are likely to occur.

In other words, in the configuration shown in FIG. 9, the small hole 1b for adjusting the sound quality is located between the central portion and the outer peripheral portion with the voice coil 13 in between, and the leading portion of the lead wire 13a at both ends and the small small portion for braking. No particular attention is paid to the positional relationship with the hole 1b, the load applied to the diaphragm 11 by the lead wires 13a at both ends becomes one of the lead-out positions P1, and the lead-out portion of the lead wires 13a at both ends is the load on the diaphragm 11 Thus, the vibration displacement at the lead-out position P1 is suppressed, and a rolling motion that vibrates in a state where the vibration film 11 is inclined is likely to occur.

In particular, the larger the input signal, the easier the rolling motion occurred, causing the following variations in performance, increased harmonic distortion, and noise such as chattering.

That is, a rolling motion is generated in the diaphragm 11 with a low frequency sound, a harmonic distortion is increased, a beat sound with respect to a high frequency signal is generated, a sound turbidity, a blur of a sound image or a performance variation is large, and a chatter sound is poor. It was easy to occur.

The beat sound is a sum signal or a difference signal of a high frequency signal and a low frequency harmonic distortion. For example, when the low frequency signal sound is 50 Hz and the high frequency signal sound is 2000 Hz, 1850, 1900, A sum signal or a difference signal such as 1950, 2050, 2100, 2150 Hz, etc.

Furthermore, due to the rolling motion, the followability to a sharp sound such as a percussion instrument deteriorated, and the faithful reproducibility of the reproduced sound easily deteriorated.

However, in the configuration of FIG. 9 described above, since the flange portion 1a and the outer peripheral area of the outer periphery from the base of the voice coil 13 in the vibration film 11 form a sealed space, a damper effect is added to the entire vibration film 11. It may be considered that the rolling motion hardly occurs in the vibration film 11.

However, since the braking small hole 1b is formed at the bottom of the yoke frame 1, the air inside and outside the voice coil 13 is circulated through the braking small hole 1b. Can not expect much.

Further, since the braking small hole 1b is formed irrespective of the lead-out position P1 of the both-end lead wire 13a, a load is applied to one position of the lead-out position P1 of the both-end lead wire 13a on the vibration film 11, and the vibration at the lead-out position P1 is caused. Since the displacement can be suppressed, it is difficult to suppress the occurrence of rolling motion.

By the way, as the shape of the vibration film 11, it is conceivable to make it difficult to be affected by the rolling motion, but it is not necessarily advantageous in terms of sound quality and input resistance.

Specifically, there are proposals that use the vibration film 11 with large unevenness or deep corrugation grooves, or use the thick vibration film 11 to increase the rigidity of the vibration film 11 itself and suppress the occurrence of rolling motion. .

However, the diaphragm 11 having such a shape has a problem that the resonance frequency f0 is high and low sound is difficult to be produced.

On the contrary, the flexible vibration film 11 that reduces the unevenness or shallows the corrugation groove and absorbs the rolling motion has problems such as large low-frequency distortion.

Thus, it has been found that there is room for improvement in the conventional speaker device in order to obtain a high-quality reproduced sound in a wide frequency band, particularly a low-frequency sound.

In recent years, speaker devices and earphone devices have been required to have higher performance due to increasing market demands for improving sound quality such as high resolution.

Therefore, as a result of earnestly examining various configurations in pursuit of further improvement in quality, the present inventor has been particularly interested in the positional relationship between the lead-out portion of the both-end lead wire 13a and the braking small hole 1b, which has not attracted much attention in the past. Attention was paid to the point where the positional relationship affected the characteristics, and a new configuration was found, thereby completing the present invention.

The present invention has been made to solve such a problem, and has an object to provide an electroacoustic transducer having a wide frequency band and excellent transient response characteristics and capable of reproducing a high-quality sound particularly in a low frequency range. And

In order to solve such a problem, the first configuration according to the electroacoustic transducer of the present invention is formed in a cup shape, and has an annular flange portion with an open front end portion extending toward the outer periphery and a bottom portion. A magnetic yoke frame having a through hole in the center, and a cylindrical drive magnet having one end face fixed to the bottom of the yoke frame so as to align the hollow portion with the through hole in the yoke frame; A ring-shaped pole piece that is coaxially stacked on the other end surface of the drive magnet so that the hollow part of the drive magnet is aligned with the hollow part in the yoke frame, and is spaced from the pole piece A thin vibrating membrane fixed so as to close the outer periphery of the flange portion so as to face to each other, and a thin insulating conductive wire is wound to form a cylindrical shape. It is a voice coil fixed to the diaphragm so as to surround the central region on one side surface, and is inserted into an annular gap between the outer periphery of the pole piece and the cylindrical part of the yoke frame, and is connected to the lead wires at both ends. A voice coil that vibrates the vibrating membrane by an applied audio signal, and has an inner magnet type configuration.

Moreover, these through holes or hollow portions are closed indirectly or directly, and the outer peripheral area of the outer periphery from the root of the voice coil in the vibration membrane faces the flange portion to form a sealed space together with this, The lead wires at both ends are led out from the same position at the base of the voice coil, and in the vicinity of the lead wire lead-out portion at the flange portion, there is a communication hole communicating from the sealed space to the outside, and the acoustic impedance of the sealed space In this configuration, a communication hole for adjustment is formed.

A second configuration of the electroacoustic transducer according to the present invention is such that one end surface is coaxial with a cylindrical magnetic yoke frame and a fixed portion formed by bending outward from one end surface side of the yoke frame. A ring-shaped drive magnet fixed to the outer periphery of the cylindrical portion of the yoke frame and facing the outer periphery of the cylindrical portion, and on the other end face side of the drive magnet on the outer periphery of the yoke frame. A ring-shaped magnetic pole piece fixed coaxially, having a tip protruding to the outer circumference of the drive magnet, and facing the yoke frame and the pole piece with a space therebetween A thin vibrating membrane fixed to the outer periphery of the tip of the pole piece, and a thin insulating conducting wire is wound to form a cylindrical shape, and the yoke frame side piece of the vibrating membrane A voice coil fixed to the diaphragm so as to surround the central region, and inserted into an annular gap between the outer periphery of the cylindrical portion of the yoke frame and the inner periphery of the pole piece, and applied to the lead wires at both ends A voice coil that vibrates the vibration film by a sound signal to be generated, and has an outer magnet type configuration.

Moreover, the hollow portion of the yoke frame is closed, and the outer peripheral region from the base of the voice coil to the outer periphery of the vibration membrane forms a sealed space facing the pole piece, and the lead wires at both ends are connected to the voice coil. A communication hole that is led out from the same position at the base and is formed in the tip portion closest to the lead wire lead-out portion from the sealed space to the outside, and is used for adjusting the acoustic impedance of the sealed space. In this configuration, holes are formed.

In the electroacoustic transducers having the first and second configurations, a configuration in which one communicating hole having an inner diameter of φ0.1 mm to φ0.8 mm is formed in the flange portion is also possible.

In the electroacoustic transducers having the first and second configurations, a plurality of the communication holes are formed in the flange portion, and the total of the opening areas is selected to be 0.079 mm ² to 0.503 mm ² . Configuration is also possible.

In the electroacoustic transducers of the first and second configurations, the lead wires at both ends are led out from the same position at the base of the voice coil to the left and right and led out from the hollow portion of the pole piece. It is also possible to have a configuration.

In the electroacoustic transducers in the first and second configurations, the lead wires at both ends may be led out from the same position at the base of the voice coil toward the outer periphery of the diaphragm.

In the first configuration according to the electroacoustic transducer of the present invention, the through hole or the hollow portion is indirectly or directly blocked, and the both end lead wires are at the same position at the root of the voice coil. The outer peripheral region of the diaphragm from the vicinity of the root of the voice coil faces the flange portion and forms a sealed space with the flange portion, and the sealed space is near the lead-out portion of the both end lead wires in the flange portion. Since a communication hole communicating from the outside to the outside is formed, it becomes easy to lower the acoustic impedance of the sealed space only in the vicinity of the communication hole in the inner magnet type configuration, reducing the load on the lead wire lead-out part, A practical sealing degree of the sealed space is ensured, and vibration of the vibrating membrane near the lead wire lead-out position from the voice coil is ensured. Rolling motion in is greatly reduced.

Therefore, smooth piston motion of the diaphragm is ensured, and as a result, excellent transient response, low distortion, and wide frequency band can be obtained. In particular, high-quality sound reproduction is possible in the low sound range.

In the second configuration relating to the electroacoustic transducer of the present invention, the hollow portion of the yoke frame is closed, the lead wires at both ends are led out from the same position at the base of the voice coil, and the voice in the diaphragm is The outer peripheral area from the base of the coil to the outer periphery forms a sealed space facing the pole piece, and communicates from the sealed space to the outside at the protruding portion of the pole piece closest to the lead wire lead-out portion. Since the formed communication hole is formed, it is easy to lower the acoustic impedance of the sealed space only in the vicinity of the communication hole in the outer magnet type configuration, reducing the load on the lead wire drawing part, and the voice The vibration of the diaphragm is secured near the lead wire lead-out position from the coil, greatly reducing rolling motion on the diaphragm. Are, we is possible to obtain a first configuration and a similar effect.

In the first and second configurations of the electroacoustic transducer according to the present invention, since the one communication hole having an inner diameter of 0.1 mm to 0.8 mm is formed in the flange portion, the one communication hole is formed. In this case, it is easy to obtain the effects described above.

In the first and second configurations according to the electroacoustic transducer of the present invention, a plurality of the communication holes are formed in the flange portion, and the total of the opening areas is 0.079 mm ² to 0.503 mm. ² is selected, it is easy to obtain the above-described effects in the configuration in which a plurality of the communication holes are formed.

In the first and second configurations of the electroacoustic transducer according to the present invention, the lead wires at both ends are led out from the same position at the base of the voice coil so as to be separated from the left and right, and the hollow portion of the pole piece Therefore, the vibration of the diaphragm is ensured.

In the first and second configurations according to the electroacoustic transducer of the present invention, the lead wires at both ends are led out from the same position at the base of the voice coil in the same direction and led out from the outer periphery of the diaphragm. Therefore, the vibration of the vibration film is ensured.

It is a principal part longitudinal cross-sectional view which shows one form of the 1st structure which concerns on the electroacoustic transducer of this invention. It is the bottom view and principal part sectional drawing of the diaphragm which concern on the electroacoustic transducer of FIG. It is a schematic longitudinal cross-sectional view which shows the electroacoustic transducer of this invention as an earphone apparatus. It is a frequency characteristic figure about the electroacoustic transducer of FIG. 1 and the electroacoustic transducer used as the reference of this invention. It is a total harmonic distortion characteristic figure about the electroacoustic transducer of FIG. 1 and the electroacoustic transducer used as the reference of this invention. FIG. 2 is a transient response waveform diagram according to the electroacoustic transducer of FIG. 1. It is a transient response waveform figure concerning the electroacoustic transducer used as a reference of the present invention. It is a principal part longitudinal cross-sectional view which shows one form of the 2nd structure which concerns on the electroacoustic transducer of this invention. It is sectional drawing which shows the electroacoustic transducer used as the reference of this invention. It is the schematic explaining operation | movement of the electroacoustic transducer used as the reference of this invention, and the electroacoustic transducer of this invention.

Hereinafter, an embodiment of an electroacoustic transducer according to the present invention will be described with reference to the drawings, taking a speaker device, for example, an earphone device as an example.

FIG. 1 is a longitudinal sectional view of an essential part showing an embodiment of a first configuration according to the speaker device of the present invention.

In FIG. 1, a yoke frame 15 is formed into a cup shape from a magnetic plate material, and is formed as a ring plate formed by bending the open end side (upper side in FIG. 1) of the cylindrical portion 15a outward. The flat flange portion 15b is integrally formed, and further, the outer peripheral portion 15c of the flange portion 15b is bent so as to rise slightly upward in the drawing.

A through hole 15e is formed at the center of the bottom 15d of the yoke frame 15, and a cylindrical (ring) drive magnet 17 is accommodated in the yoke frame 15 so that the hollow portion 17a is aligned with the through hole 15e. Yes. That is, the drive magnet 17 is housed in the yoke frame 15 with one end face (lower side in FIG. 1) overlapped with the bottom portion 15d so as to surround the through hole 15a.

On the other end face (upper side in FIG. 1) of the drive magnet 17, a ring-shaped pole piece formed of a magnetic material having an outer diameter that is the same as or slightly larger than the outer diameter of the drive magnet 17. 19 are stacked. The pole piece 19 has a hollow portion 19 a so as to align with the hollow portion 17 a of the drive magnet 17.

On the outside of the bottom 15d of the yoke frame 15, a circuit board 21 having through holes 21a is overlaid so that the through holes 21a and the through holes 15e are aligned.

The yoke frame 15, the drive magnet 17, the pole piece 19, and the circuit board 21 are formed of a tubular fitting 23 that is penetrated from the pole piece 19 or the circuit board 21 side through the hollow portions 17a and 19a and the through holes 15e and 21a. The two ends are coaxially integrated and fixed to the bottom 15 d of the yoke frame 15.

The yoke frame 15, the drive magnet 17, the pole piece 19, and the circuit board 21 may be coaxially integrated with an adhesive or the like (not shown) and fixed to the yoke frame 15.

The pole piece 19 has its outer periphery facing the tip of the cylindrical portion 15a of the yoke frame 15, that is, at the same level position as the bent portion from the cylindrical portion 15a to the flange portion 15b, and the magnetic flux concentration for obtaining high sound quality. However, the drive magnet 17 can be identified with the same.

A magnetic circuit is formed by the magnetic flux from the yoke frame 15 between the outer periphery of the pole piece 19 and the tip of the cylindrical portion 15a of the yoke frame 15 which is opposed to the outer periphery of the pole piece 19.

As shown in FIGS. 2A and 2B, the vibration film 25 is formed in a disk shape from a conventionally known thin and translucent insulating film material, and a central area formed by slightly expanding a relatively wide central portion into a dome shape. 25a and an outer peripheral region 25b concentrically surrounding the central region 25a in an annular shape. FIG. 2A shows the pole piece 19 and the flange portion 15b seen through the translucent vibrating membrane 25. FIG.

Although not shown in the drawing, the outer peripheral region 25b of the vibration film 25 is formed with radial fine irregularities called a so-called corrugation edge, and the central region 25a is, for example, 1.5 times the outer peripheral region 25b. It will preferably be as strong as about 2 to 5 times.

As shown in FIG. 1, the vibration film 25 covers the flange portion 15b and the pole piece 19 of the yoke frame 15 with a space, and covers the outer periphery of the outer peripheral region 25b around the outer peripheral portion 15c of the flange portion 15a. It is fixed to and supported by an adhesive or the like.

On one surface side (the lower surface side in FIG. 1) of the vibration film 25, a voice coil 27 formed by winding a thin insulated conductor wire coated in a cylindrical shape at the annular boundary between the central region 25a and the outer peripheral region 25b. One end face side is fixed so as to surround the central region 25a.

The voice coil 27 is slightly spaced from the yoke frame 15, the drive magnet 17, and the pole piece 19 in an annular gap between the inner wall of the cylindrical portion 15 a of the yoke frame 15 and the outer periphery of the drive magnet 17 and the pole piece 19. It is inserted and faces the inner periphery of the yoke frame 15 and the outer periphery of the drive magnet 17 in an annular shape.

Two lead wires 27a from the voice coil 27 are led inward from the same position at the base of the voice coil 27, and the hollow portion 23a of the fitting 23, that is, the pole piece 19 and the hollow portions 19a and 17a of the drive magnet 17 are provided. Further, it is led out to the outside through the bottom 15 d of the yoke frame 15 and the through holes 15 e and 21 a of the circuit board 21, and is connected to the circuit board 21.

Note that the lead wires 27a at both ends may be fixed to the upper end of the fitting 23 with a flexible adhesive (not shown).

The lead wires 27a at both ends are wired in the air with a margin so as not to be stressed by vibrations of the vibration film 25, which will be described later, and as shown in FIG. 2A, for example, left and right from the root of the voice coil 27. In addition, it is led out from the hollow portion 19a of the pole piece 19, and is bent into a heart-like shape when viewed from the front or back surface of the vibration membrane 25.

Note that the two end lead wires 27a do not have to be derived from exactly the same position, and include a configuration in which they are derived from slightly separated positions as shown in FIG. 2A.

In the vibrating membrane 25, the outer peripheral region 25b from the vicinity of the root of the voice coil 27 faces the sealed space E formed in the yoke frame 15 and the flange portion 15b, as shown in FIG.

That is, the outer peripheral region 25b from the vicinity of the root of the voice coil 27 in the vibration film 25 faces the flange portion 15b and forms a sealed space E together therewith.

The sealed space E is a hollow portion of the fitting 23 through a narrow annular gap between the voice coil 27 and the drive magnet 17 or the pole piece 19 from a narrow gap between the cylindrical portion 15a of the yoke frame 15 and the voice coil 27. It communicates with 23a.

In addition, the structure which seals the inside of the hollow part 23a while filling the inside of the hollow part 23a with the foaming urethane which is not shown in figure and fixing the both-ends lead wire 27a in the hollow part 23a is also possible.

However, since the hollow portion 23a of the eyelet 23 is closed by the sealing member 29 from the circuit board 21 side, the sealed space E is sealed and the entire outer peripheral region 25b of the vibrating membrane 25 is supported with a uniform load. It functions as an air damper.

In the flange portion 15b of the yoke frame 15, one communication hole 15f communicating from the sealed space E to the outside is formed near the lead-out portion of the both-end lead wire 27a.

The communication hole 15f is a member for adjusting the acoustic impedance of the sealed space E, and has a function of reducing the acoustic impedance of the sealed space E and facilitating vibration without suppressing the vibration of the vibrating membrane 25 in the vicinity thereof. ing. The inner diameter of the communication hole 15f may be selected in the range of φ0.1 mm to 0.8 mm according to the target characteristics.

An audio signal is supplied from an electronic device (not shown) to the circuit board 21 superimposed on the bottom 15d of the yoke frame 15 through a cable 31 described later.

When the voice signal is applied to the voice coil 27 via the lead wires 27a at both ends, the voice coil 27 is displaced, and the vibrating membrane 25 is driven to vibrate.

That is, the yoke frame 15, the drive magnet 17, and the voice coil 27 form a drive unit 33 that vibrates and drives the vibration film 25, and is a main part of a so-called inner magnet type speaker device.

Next, a configuration in which the speaker device having this configuration is commercialized will be described.
As shown in FIG. 3, the yoke frame 15 is manufactured by fitting the outer peripheral portion 15 c of the flange portion 15 b into a cap-shaped case main body 35 and supporting it in the case main body 35.

The case main body 35 described above includes a large-diameter cylindrical portion 35a into which the outer periphery of the yoke frame 15 fits, and a small-diameter cylindrical portion 35b that is continuous from the large-diameter cylindrical portion 35a and has substantially the same dimensions as the yoke frame 15. And integrally molded from an insulating synthetic resin or the like.

The yoke frame 15, the drive magnet 17, and the pole piece 19 are integrated and fitted inside the large-diameter cylindrical portion 35a, and fixedly supported inside the large-diameter cylindrical portion 35a.

The small-diameter cylindrical portion 35b of the case body 35 covers the vibrating membrane 25 with a space therebetween, and extends so as to protrude upward in FIG.

In the speaker device having the above-described configuration, the case body 35 covers the yoke frame 15 and the circuit board 21 by covering the outer surface of the large-diameter cylindrical portion 35a with the cover substrate 37 and the like, and a flexible ear around the small-diameter cylindrical portion 35b. The chip 39 is fitted and commercialized as an earphone device.

In such a speaker device, by supplying an audio signal from the cable 31 via the circuit board 21 and applying the audio signal to the voice coil 27, the drive unit 33 vibrates the vibration film 25, and the sound-cylinder body. The vibration sound is propagated to the outside through the small diameter cylindrical portion 35b.

Although not shown, the speaker device according to the present invention houses the case main body 35 in the concha cavity surrounded by the user's tragus, antitragus and concha, and the ear tip 39 at the tip. It is inserted into the ear canal (not shown) and used.

In such a configuration according to the speaker device of the present invention, the lead-out position P1 becomes a vibration node when the vibration film 25 vibrates due to a load caused by the lead-out position P1 of the both-end lead wire 27a from the voice coil 27. A rolling motion centering on the

However, in the speaker device of the present invention, the sealed space E facing the outer peripheral region 25b of the vibrating membrane 25 is a narrow flat space formed between the flange portion 15b of the yoke frame 15 and the outer peripheral region 25b of the vibrating membrane 25. Yes, it functions as an air damper facing the entire circumference of the outer peripheral area 25b of the vibration film 25, and holds the vibration film 25 in a state where a uniform mechanical load is applied to the entire circumference of the outer peripheral area 25b.

Moreover, in the flange portion 15b, since one communicating hole 15f communicating from the sealed space E to the outside is formed in the vicinity of the leading portion of the lead wires 27a at both ends, the displacement at the leading position P1 cannot be suppressed, and the diaphragm 25 Is easy to vibrate.

That is, the load due to the lead portion 27a of the both end lead wires 27a with respect to the vibration film 25 and the partial reduction in acoustic impedance with respect to the sealed space E by the communication hole 15f are balanced, and the rolling motion of the vibration film 25 is greatly reduced.

Therefore, it is difficult for rolling vibration to occur in the vibration film 25, and it is difficult for the outer peripheral region 25b of the vibration film 25 to be loosened.

Even if the both ends lead wire 27a is led out from one place in combination with such an operation, as shown in FIG. 10C, the entire diaphragm 25 is uniformly displaced in the piston mode, a wide frequency band, an excellent transient response waveform, In particular, it is possible to obtain high-quality reproduced sound in a low sound range. Specifically, the feeling of localization of a musical instrument or the like is improved, and the reproduced sound is easily discriminated.

On the other hand, in the speaker device shown in FIG. 9, if the low frequency response is improved, the vibration amplitude of the vibration film 25 increases, so that the rolling motion becomes larger, and abnormal vibration such as increased distortion and generation of chatter noise occurs. It is likely to occur.

In the speaker device shown in FIG. 9, the diaphragm 7 is likely to cause an operation called unbalanced rolling due to the load of the lead wires 9a as shown in FIG. 10A. Therefore, in order to absorb some distortion during vibration of the diaphragm 7, it is general to make the portion corresponding to the central region 7 a have a spherical shape so as to bend and vibrate to some extent.

In the configuration of the present invention, since a rolling motion is difficult to occur, distortion such as twisting is difficult to occur in the outer peripheral region 25b, and the degree of freedom in designing the corrugation edge portion can be greatly improved compared to the conventional configuration. Is possible. In addition, since there is little occurrence of distortion, chatter noise, etc., the response in the low range can be controlled relatively freely.

In the configuration of the speaker device according to the present invention, it can be seen that high-quality sound reproduction is possible in a wide frequency band, as shown by the solid line a in FIG. Like the total harmonic distortion characteristic, the harmonic distortion characteristic is low and flat up to a low sound range.

On the other hand, in the configuration shown in FIG. 9, although the response in the mid-low range is lower than the solid line a in the frequency characteristic diagram of the present invention as shown by the broken line b in FIG. Like the total harmonic distortion characteristic indicated by the broken line b, the harmonic distortion characteristic is poor, and in particular, the deterioration of the mid-low range portion around 1 KHz or less is conspicuous.

The sealed space E in the present invention includes, for example, an annular gap (for example, about 0.3 mm) between the drive magnet 17 and the pole piece 19 and the yoke frame 15 and a hollow portion 17a of the drive magnet 17 and a through hole 15e of the yoke frame 15. However, since the inside is completely sealed by the sealing member 29, the sealing space E is highly sealed, and thereby the effect of the communication hole 15f is more exhibited.

Furthermore, the transient response waveform shown in the configuration of the speaker device according to the present invention is as shown in FIG. 6, and there is little disturbance in the output signal waveform when the tone burst signals of 200 Hz and 1000 Hz are applied, and the transient response waveform is good. I understand that.

On the other hand, in the configuration of FIG. 9, as shown in FIG. 7, a relatively large disturbance occurs in the output signal waveform when the tone burst signals of 200 Hz and 1000 Hz are applied, and the transient response waveform of the speaker device according to the present invention is improved. You can see that

As described above, the first configuration according to the speaker device of the present invention has a wide frequency band and excellent transient response characteristics, and can reproduce high-quality sound particularly in the low sound range.

In the present invention, the communication hole 15f formed in the flange portion 15b can be selected within the range of the inner diameter φ0.1 mm to 0.8 mm according to the target characteristics. That is, if the inner diameter of the communication hole 15f is made smaller than the above range, sufficient low frequency characteristics cannot be obtained, and if it is increased, the low frequency is excessive or the bumper effect of the sealed space E is reduced. Rolling motion is likely to occur.

In the present invention, the number of communication holes 15f formed in the flange portion 15b is not limited to one, and a plurality (for example, about 2 to 4) may be formed (see FIG. 2C). The object of the present invention can be achieved if the total area of the plurality of communication holes 15f is about 0.079 mm ² to 0.503 mm ² .

Further, in the present invention, as shown by the broken line in FIG. 2A, the two end lead wires 27b are led out from the same position at the base of the voice coil 27, and the vibration film is formed at the outer peripheral portion 15c of the flange portion 15b. A configuration in which it is led out from between 25 and the outside is also possible.

Further, in the present invention, the hollow portion 23a of the fit 23 is not limited to the configuration in which the hollow portion 23a is closed with the sheet-like sealing member 29, but the hollow of the yoke frame 15 and the through holes 15e and 21a of the circuit board 21, the drive magnet 17 and the pole piece 19 If the portions 17a and 19a are closed indirectly or directly, the object of the present invention can be achieved.

Next, a second configuration, that is, an external magnet type speaker device according to the speaker device of the present invention will be described.
FIG. 8 is a longitudinal sectional view of an essential part showing one form of a second configuration according to the speaker device of the present invention.

In FIG. 8, a yoke frame 41 is formed from a magnetic plate material into a cylindrical shape, and a ring plate-like fixing portion 41a formed by bending the lower open end in the figure outward is integrated. Have.

A ring-shaped drive magnet 43 is coaxially fitted to the outer periphery of the yoke frame 41 at a distance from the outer periphery of the cylindrical portion 41b, and one end surface (lower side in FIG. 8) is fixed to the fixing portion 41a. ing.

On the other end surface of the drive magnet 43 (upper side in FIG. 8), a pole piece 45 having an inner diameter substantially the same as or slightly smaller than the inner diameter of the drive magnet 43 and formed from a magnetic material into a ring plate shape is overlaid. ing.

The pole piece 45 has a tip portion 45a formed so as to protrude further from the outer periphery of the drive magnet 43, that is, a protruding portion, and the outer periphery of the tip portion 45a is bent slightly upward (upper side in FIG. 8).

The drive magnet 43 and the pole piece 45 have the same outer circumference, and both the inner circumference of the pole piece 45 protrudes inward from that of the drive magnet 43. The pole piece 45 is arranged on the yoke frame 41. It faces the circumference at the same level position as the other tip.

A circuit board 47 is overlaid on the outside of the fixed portion 41 a of the yoke frame 41.
The fixed portion 41 a of the yoke frame 41, the drive magnet 43, the pole piece 45, and the circuit board 47 are coaxially integrated with, for example, an adhesive and fixed to the fixed portion 41 a of the yoke frame 41.

A magnetic circuit is formed by the magnetic flux from the yoke frame 41 between the inner periphery of the pole piece 45 and the front end of the yoke frame 41 facing the pole piece 45 with a slight gap therebetween.

As in FIG. 2, the vibration film 49 is formed in a disk shape from a conventionally known thin insulating film material, and a central region 49a formed by slightly expanding a relatively wide central portion into a dome shape, and the central region An outer peripheral region 49b concentrically and annularly surrounding 49a. Other configurations of the vibration film 49 are the same as those of the vibration film 25 in FIG.

The vibration film 49 covers the yoke frame 41 and the pole piece 45 with a space and fixes the entire outer edge of the outer peripheral region 49b to the outer periphery of the tip 45a of the pole piece 45 with an adhesive or the like. It is supported.

On one surface side (lower surface side in FIG. 8) of the vibrating membrane 49, one end surface side of the cylindrical voice coil 51 surrounds the central region 49a at the annular boundary between the central region 49a and the outer peripheral region 49b. It is fixed.

Similar to the voice coil 27 described above, the voice coil 51 is formed by integrally winding a thin insulated conductor wire coated in a cylindrical shape, and the outer wall of the yoke frame 41 and the inner periphery of the drive magnet 43 and the pole piece 45. Between the yoke frame 41 (cylindrical portion 41 b), the drive magnet 43 and the pole piece 45 with a slight gap between them, and the outer periphery of the yoke frame 41 and the inside of the drive magnet 43 and the pole piece 45. It faces to the circumference in a ring.

Both-end lead wires 51a from the voice coil 51 are led out from the same location, and are connected to the circuit board 47 through the hollow portions 41c of the yoke frame 41 and the through holes 47a of the circuit board 47.

The outer peripheral region 49 b of the vibration film 49 faces the sealed space E formed between the pole piece 45.

The sealed space E is communicated with the hollow portion 41 c of the yoke frame 41 through a narrow gap between the yoke frame 41 and the voice coil 51 via the pole piece 45 and the drive magnet 43 and the voice coil 51.

The through hole 47a of the circuit board 47 is closed by a sheet-like sealing member 53 to seal the sealed space E, and the sealed space E has a function of supporting the entire outer peripheral region 49b of the voice coil 51 with a uniform load. Have.

Further, the circuit board 47 may be configured such that the through hole 47a is not formed and the sealing member 53 is not used. In short, the space formed by the yoke frame 41 and the vibration film 49 may be sealed.

In the pole piece 45, one communication hole 45b communicating from the sealed space E to the outside is formed in the vicinity of the lead-out portion of the both-end lead wire 51a.

As in the first configuration described above, one communication hole 45b having an inner diameter of about 0.1 mm to 0.8 mm in diameter may be formed. If the total of these is about 0.079 mm ² to 0.503 mm ² , the object of the present invention can be achieved.

An audio signal is supplied from an electronic device (not shown) to the circuit board 47 overlaid on the fixed portion 41a of the yoke frame 41 via a cable (not shown), and the audio signal is sent to the voice coil 51 via the lead wires 51a at both ends. , The voice coil 51 is displaced, and the vibration film 49 is driven to vibrate.

That is, the drive part 55 that vibrates and drives the vibration film 49 is formed by the yoke frame 41, the drive magnet 43, and the voice coil 51, and is a main part of a so-called outer magnet type speaker device.

The yoke frame 41 is fitted in the cap-shaped case main body 35 and supported in the case main body 35 as shown in FIG. 3 described above, but illustration and description thereof are omitted. The same applies to examples of commercialization and use as earphone devices.

In the speaker device having the second configuration as described above, by supplying an audio signal through the circuit board 47 and applying the audio signal to the voice coil 51, the drive unit 55 causes the vibration film 49 to vibrate and vibrate. Is propagated to the outside.

In the second configuration of the present invention, the sealed space E can achieve the object of the invention if the hollow portion 41c of the yoke frame 41 is closed, and the sealed space E is not necessarily sealed by the circuit board 47 or the sealing member 53. It is not limited.

Further, the second configuration of the present invention is similar in operation and effect to the first configuration, and the frequency characteristics and the total harmonic distortion characteristics are as shown in FIGS. It has transient response characteristics and can reproduce high-quality sound particularly in the low sound range.

Further, in the speaker device of the present invention, the sound passage cylinder formed by the small-diameter cylindrical portion 35b of the case main body 35 protrudes along the central axis of the case main body (small-diameter cylindrical portion) 35. Alternatively, a configuration that projects in an oblique direction is also possible.

Note that the electroacoustic transducer of the present invention can be widely used as a headphone or a microphone.

1, 15, 41 Yoke frames 1a, 15b, 47a Flange 1b Small holes for braking 3, 17, 43 Drive magnets 5, 19, 45 Pole pieces 7, 21, 47 Circuit boards 9, 23 Fittings 9a, 17a, 19a , 41c Hollow portions 11, 25, 49 Vibration membranes 13, 27, 51

Voice coils

13a, 27a, 27b, 51a Lead wires 15a, 41b Cylindrical portion 15c Outer peripheral portion 15d Bottom portions 15e, 21e, 47a Through holes 15f, 45b Communication Holes 25a, 49a Central areas 25b, 49b Outer peripheral areas 29, 53 Sealing members 31 Cables 33, 55 Drive part 35 Case body 35a Large diameter cylindrical part 35b Small diameter cylindrical part 37 Cover substrate 39 Ear tip 41a Fixing part 45a Tip E Sealed space P1 lead-out position

Claims

A magnetic yoke frame that is formed in a cup shape and has an annular flange portion that has an open front end portion extending toward the outer periphery, and a through-hole in the center of the bottom portion;
A cylindrical drive magnet having one end face fixed to the bottom of the yoke frame so that the hollow portion is aligned with the through hole in the yoke frame;
A ring-shaped pole piece coaxially stacked on the other end surface of the drive magnet so as to align the hollow portion of the drive magnet with the hollow portion in the yoke frame;
A thin diaphragm fixed so as to close the outer periphery of the flange portion so as to face the pole piece with a gap;
A voice coil which is formed in a cylindrical shape by winding a thin insulated conductor, and is fixed to the vibration film so as to surround a central region on one side of the vibration film on the yoke frame side, the outer periphery of the pole piece and the cylinder of the yoke frame A voice coil that is inserted into an annular gap between the shape parts and vibrates the vibrating membrane by an audio signal applied to both end lead wires;
Comprising
The through-hole or the hollow portion is indirectly or directly blocked, and the outer peripheral region of the outer periphery from the vicinity of the root of the voice coil in the vibration membrane faces the flange portion to form a sealed space together therewith, The lead wires at both ends are led out from the same position at the base of the voice coil, and in the vicinity of the lead-out portion of the lead wires at the flange portion, there are communication holes communicating from the sealed space to the outside, An electroacoustic transducer having a communication hole for adjusting acoustic impedance.
The electroacoustic transducer according to claim 1, wherein one communication hole having an inner diameter of 0.1 mm to 0.8 mm is formed in the flange portion.
The electroacoustic transducer according to claim 1, wherein a plurality of the communication holes are formed in the flange portion, and the total area of the holes is selected from 0.079 mm 2 to 0.503 mm 2 .
The electroacoustic according to any one of claims 1 to 3, wherein the both-end lead wires are led out from the same position at the base of the voice coil to the left and right and led out from the hollow portion of the pole piece. Conversion device.
The electroacoustic transducer according to any one of claims 1 to 3, wherein the lead wires at both ends are led out from the same position at the base of the voice coil toward the outer periphery of the diaphragm.
A cylindrical magnetic yoke frame,
A ring-shaped drive magnet having one end face coaxially fixed to a fixed portion bent outwardly from one end face side of the yoke frame, and spaced apart from the outer periphery of the cylindrical portion of the yoke frame. Drive magnets facing each other,
A ring-shaped pole piece coaxially fixed to the other end surface side of the drive magnet on the outer periphery of the yoke frame, and a pole piece having a tip protruding to the outer periphery from the drive magnet;
A thin diaphragm fixed to the outer periphery of the tip of the pole piece so as to face the yoke frame and the pole piece at a distance;
A voice coil that is formed in a cylindrical shape by winding a thin insulated conductor, and is fixed to the vibration film so as to surround a central region on one side of the vibration film on the yoke frame side, and the outer periphery of the cylindrical portion of the yoke frame A voice coil that is inserted into an annular gap between the inner periphery of the pole piece and vibrates the vibrating membrane by an audio signal applied to the lead wires at both ends;
Comprising
The hollow portion of the yoke frame is closed, and the outer peripheral region from the vicinity of the root of the voice coil in the vibration membrane faces the pole piece to form a sealed space, and the both end lead wires are the root of the voice coil. A communication hole formed in the tip end portion closest to the lead-out portion of the both end lead wires from the sealed space to the outside, and for communicating the acoustic impedance of the sealed space An electroacoustic transducer having holes formed therein.
The electroacoustic transducer according to claim 6, wherein one communication hole having an inner diameter of 0.1 mm to 0.8 mm is formed in the flange portion.
The electroacoustic transducer according to claim 6, wherein a plurality of the communication holes are formed in the flange portion, and the total area of the holes is selected from 0.079 mm 2 to 0.503 mm 2 .
The electroacoustic conversion according to any one of claims 6 to 8, wherein the lead wires at both ends are led out from the same position at the base of the voice coil so as to be separated from the left and right and from the hollow portion of the pole piece. apparatus.
The electroacoustic transducer according to any one of claims 6 to 8, wherein the lead wires at both ends are led out from the same position at the base of the voice coil toward the outer periphery of the diaphragm.