Insert type headphone

The present invention relates to insert-type headphones that are used by attaching or inserting a sound emitting portion into the entrance of the ear canal.

In so-called insert-type headphones or earphones in which the conventional sound emitting part is attached to the recess in the auricle or the entrance of the external auditory canal, in order to achieve high fidelity in the entire range of the reproduced sound, particularly improvement in frequency characteristics in the low range. Various attempts have been made, but the policy common to these attempts is to communicate with the outside air through the sound emitting space in front of the diaphragm, which is sealed by cutting off the communication with the outside air at the time of mounting, to some extent. By lowering it, the frequency characteristics from the bass range to the treble range, especially in the bass range, are improved.

The sound emitting part is only the sound emitting side of the almost disk-shaped driver unit including the diaphragm and the magnetic circuit, and the sound emitting part is forward from the sound emitting side along the almost central axis of this driver unit, that is, in the ear canal. It may be an anterior air chamber that includes a tubular portion that projects toward it. In the former case, the headphones are attached to the auricle inner recess, that is, the ear canal, via the elastic ear pads provided on the outer peripheral surface of the housing surrounding the driver unit, with the sound emitting side facing the ear canal. In the latter case, the anterior air chamber including the tubular portion is formed by a front housing for accommodating the driver unit, and is inserted and held at the entrance of the ear canal by a flexible cushion member covering the outer circumference of the tubular portion, and is inserted and held on the back side of the driver unit. Is covered with a rear housing that derives the cord from the magnetic circuit and attaches to the front housing.

In the inner ear type headphones described in Japanese Patent Application Laid-Open No. 1-101795, which is an example of a type in which the housing surrounding the driver unit is attached to the ear canal via an ear pad, first, the wearability of the headphones to the ear canal is improved and the housing is provided. The length and thickness of the ring-shaped foamed plastic ear pads that have been attached to the outer periphery of the housing to allow air to flow between the outer peripheral surface and the peripheral wall of the ear canal are considerably increased, and the entire surface is coated with a thin film such as rubber. By doing so, sound leakage to the outside is reduced due to high airtightness and sound resistance while maintaining good fit to the ear canal. Further, in order to acoustically connect the front surface and the back surface of the diaphragm, a unit case that surrounds the outer periphery of the driver unit through a gap a and communicates the sound emitting space on the front surface of the diaphragm and the rear space inside the housing. , A bypass ring that separates the gap b connecting the back surface of the diaphragm and the rear space from the gap a through a hole made in the yoke of the magnetic circuit that holds the periphery of the diaphragm is provided, and an acoustic resistor is interposed in each gap a and b. By enlarging the gap of the gap a, a sound pressure characteristic with a wide frequency band balanced in both high and low frequencies can be obtained. Although not specified, the rear housing of the driver unit is not provided with a ventilation hole to contribute to the prevention of sound leakage, and the rear space is communicated with the outside through the gap a and the ear pad.

Another example of headphones that do not have ear pads but are worn in the ear canal is described in Jinkaisho 61-206390, in which the rear housing has a length to improve the frequency response in the bass range. A variable tubular duct portion is provided, and the sound in the rear housing that is communicated to the back surface of the diaphragm is emitted to the outside by the duct portion, and the frequency characteristics in the low frequency range are improved. Desirable acoustic control is possible by changing the length of the duct portion.

An example of an earphone of a type in which a tubular sound emitting portion is inserted and held at the entrance of the ear canal by a cushion member is described in Japanese Patent Application Laid-Open No. 2000-341784, and for good adhesion of the flexible cushion portion to the peripheral surface of the entrance of the ear canal. By communicating the sound emitting space in front of the diaphragm with an increased degree of sealing to the outside to the outside air from the entrance of the ear canal, the sound "community" due to the sensitivity enhancement of the bass frequency band generated in the sealed sound emitting space is prevented. Means are disclosed. This means is provided in a portion of the front housing that is formed continuously and integrally with the tubular sound emitting portion to accommodate and fix the driver unit, and is not covered by the cushion member when the sound emitting portion is attached to the entrance of the external auditory canal. It consists of a ventilation hole that allows the sound space to communicate with the outside air, and a damper that is installed inside the ventilation hole and serves as a ventilation resistor on which the driver unit is mounted. The ventilation resistance damper is a pressed urethane that adjusts the ventilation characteristics of urethane foam, and part of the sound radiated from the front of the driver unit into the sealed sound emitting space is given leakage resistance by the ventilation resistance damper and leaks to the outside from the ventilation holes. To do. The sound radiated from the small hole on the back of the driver unit to the back side is leaked to the outside from the ventilation hole provided in the rear housing of the earphone through the same ventilation resistance damper, and the acoustic characteristics in the low frequency range are improved.<patcit num="1"><text>Japanese Patent Application Laid-Open No. 1-101795</text></patcit><patcit num="2"><text>Jitsukaisho 61-296390</text></patcit><patcit num="3"><text>Japanese Unexamined Patent Publication No. 2000-341784</text></patcit>

<p> However, in addition to providing a considerably thick foamed plastic ear pad on the outer circumference of the housing in order to enhance the bass range, the headphones shown in JP-A-1-101795 are further on the front surface of the diaphragm along the inner peripheral surface thereof. A gap must be provided to connect the headphone and the back surface, and the outer diameter of the headphone itself, and therefore the diameter of the diaphragm, is subject to design restrictions. On the other hand, since the rear housing is not provided with a ventilation hole, the sound on the back side of the diaphragm is once returned to the front of the diaphragm through the gap along the inner circumference of the ear pad, and is emitted to the outside through the ear pad. Since the ear pad has a thin film with high airtightness and sound wave resistance that covers the surface to improve the problem of sound leakage, the airtightness of the sound emitting space on the front of the diaphragm is not reduced, and the sound from the back of the diaphragm is not reduced. There is a problem that the phenomenon of "komori" is promoted by superimposing.</p><p> In the case of the headphones described in Gazette No. 61-206390, the improvement of bass frequency characteristics is achieved by providing a duct part in the rear housing on the back side of the diaphragm. There is no suggestion of a solution to this problem. Further, it is shown that the desired acoustic control is achieved by making the length of the duct portion variable, but this is only the control on the back side of the diaphragm and the control regarding the degree of sealing or the degree of leakage on the front side of the diaphragm. Or, it does not suggest to the acoustic adjustment, and the problem of this point remains.</p><p> In the earphones described in JP-A-2000-341784, the airtightness of the sound emitting space is lowered by making a hole in the front air chamber of the front housing that divides the sound emitting space, and a part of the radiated sound of the diaphragm is sent to the front air. The ventilation holes provided in the anterior air chamber prevent the generation of "komori" by leaking from the room, but on the contrary, the sound outside the anterior air chamber, especially the wind noise generated during the walking of the user, is anterior. There is a problem that it is taken into the room and causes discomfort. Further, if the decrease in the degree of sealing is excessive or insufficient, the sound leakage is not stable and the desired wide band frequency characteristic cannot be obtained. According to the description in the publication on this point, in addition to pressed urethane whose ventilation characteristics have been adjusted, a non-woven fabric having no elasticity can be used as the ventilation resistor, but in the case of pressed urethane, between the driver unit and the front housing. It is necessary to ensure that the radiated sound leaks through the pressed urethane and the ventilation holes without creating a gap around the driver unit due to compression pinching, and when using a non-elastic non-woven fabric, a gap is likely to occur. Particular attention should be paid to the installation of the ventilation resistor in the ventilation holes, such as by applying an adhesive or the like to the butt surface to prevent this. However, while this caution must be paid for each assembly of related parts, there remains the problem that the finished product will vary because it cannot be configured in advance. Furthermore, in the configuration described in this publication, the ventilation resistor is fixed in a compressed and sandwiched state, and the degree of leakage is determined by the material of the ventilation resistor to be adopted, so that products with different specifications can be made with the same parts. There is also the problem that acoustic adjustment cannot be achieved at the assembly stage.</p><p> The present invention has been proposed to solve these problems, and its first purpose is to pass a sound emitting space on the front surface of the diaphragm, which is sealed when the diaphragm is attached or inserted into the ear canal, through a space on the back side of the diaphragm. By communicating to the outside, it is possible to prevent the occurrence of "combination" of sound in the sound emission space, and to provide insert-type headphones with improved frequency characteristics in the entire range from bass to treble.</p><p> Further, the second purpose is to obtain a configuration in which a closed sound emitting space is communicated to the outside through a space on the back side of the diaphragm as an assembly of parts modularized in advance according to desired acoustic characteristics. It is in the offer of insert type headphones.</p><p> A third object is to provide insert-type headphones capable of adjusting the reproduced sound by giving a function of adjusting the degree of communication to a configuration that communicates the space before and after the diaphragm and the external space.</p>

<p> In order to solve the above problems, the insert type headphones according to the present invention have a protector plate having a sound emitting opening to protect the sound emitting side on the front surface of the diaphragm, and one of the diaphragm driving circuits on the back side of the diaphragm. A driver unit having a yoke plate that constitutes a part and holds the outer periphery of the diaphragm at the outer peripheral end wall, and a sound emitting space in front of the protector plate and a back space that communicates with the outside behind the yoke plate are partitioned by accommodating the driver unit. It is equipped with a housing and a communication passage that communicates a sound emitting space that is sealed when the headphones are attached to the ear canal to the back space via a ventilation resistor, and the communication passage is a slit provided on the outer peripheral end wall of the yoke plate of the driver unit. The ventilation resistor is characterized in that it closes the back space side of the slit.</p><p> The insert-type headphones according to the present invention include a ring-shaped unit holder in which a driver unit extends inward from an outer peripheral wall and one end thereof to have a vent and a flange portion for partitioning a central opening, and the unit holder has an outer peripheral wall. The outer peripheral end wall of the yoke plate is surrounded by a wall, the flange portion is positioned on the step portion on the back space side adjacent to the outer peripheral end wall of the yoke plate to accommodate the driver unit, and the ventilation resistor is formed in a ring shape. It is characterized in that it is arranged between the flange portion of the unit holder and the rear space side step portion of the yoke plate.</p><p> The insert-type headphones according to the present invention are characterized in that a slit forming a continuous passage is formed from the outer peripheral end wall of the yoke plate of the unit holder to the adjacent rear space side step portion.</p><p> The insert-type headphones according to the present invention are characterized in that the flange portion of the unit holder has a ventilation expansion portion having a central opening at a portion corresponding to a slit in the outer peripheral end wall of the driver unit.</p><p> The insert-type headphone according to the present invention includes a front housing body that partitions the sound emitting space and a rear housing body that partitions the rear space, and the front housing body forms the front side of the outer peripheral end wall of the yoke plate of the driver unit. In a housing having a tubular sound emitting portion that is reduced in diameter from the pedestal portion and extends forward so as to partition the sound emitting space so as to face the sound emitting portion of the receiving pedestal portion and the protector plate, the pedestal portion is a driver. The unit is provided with a slit and a ventilation groove connected to the sound emitting space on the inner peripheral surface facing the slit on the outer peripheral end wall of the yoke plate.</p><p> In the insert type headphones according to the present invention, the outer peripheral wall of the unit holder extends beyond the outer peripheral end wall of the yoke plate of the driver unit and is joined to the outer peripheral surface of the pedestal portion of the front housing body that receives the outer peripheral end wall of the yoke plate. The driver unit is held by the front housing body.</p><p> In the insert type headphones according to the present invention, the outer peripheral wall of the unit holder has a slit facing the slit of the outer peripheral end wall of the yoke plate of the driver unit, and the pedestal portion of the front housing body is at least yoked with the facing slit of the unit holder. It is characterized by having a protrusion that engages with a part of a slit in the outer peripheral end wall of the plate.</p><p> The insert-type headphones according to the present invention are characterized in that the number of ventilation holes of the unit holder or the total aperture ratio of the ventilation holes and the ventilation expansion portion is determined according to a desired acoustic characteristic.</p><p> The insert-type headphones according to the present invention are characterized in that the ventilation resistor is a foamed compressed body in which the compression ratio is determined according to a desired acoustic characteristic.</p>

<p> According to the present invention, the slit provided on the outer peripheral edge of the driver unit of the insert type headphones communicates the sound emitting space in the housing, which is sealed when the headphones are attached to the ear canal, with the back space communicating with the outside. Prevents the generation of sound in the sound space, there is no wind noise that occurs when the sound emitting space is directly communicated with the outside, and not only the improvement in the low range but also the frequency characteristics in the entire range including the high range Improvements can be achieved.</p><p> Further, according to the present invention, the pedestal portion of the front housing body that receives the front side of the outer peripheral end of the driver unit of the insert type head has a ventilation groove that connects the communication slit at the outer peripheral end of the driver unit and the sound emitting space. , The outer peripheral wall of the unit holder that presses the ventilation resistor to the back side of the outer peripheral end of the driver unit at the flange portion extends beyond the outer peripheral end of the driver unit and joins to the outer peripheral surface of the pedestal portion, and has a slit facing the communication slit. Since the pedestal portion has a positioning protrusion that engages with the facing slit of the unit holder and at least a part of the communication slit of the driver unit, these front housing bodies, the driver unit, the ventilation resistor, and the unit holder are assembled. This has a remarkable effect in that a module having a desired communication function and acoustic characteristics is formed.</p><p> Further, according to the present invention, the degree of ventilation resistance given by the ventilation resistor to the communication through the air or sound slit of the sound emitting space in the back space communicating with the outside in the housing of the insert type headphone and the ventilation resistor are retained. Since the ventilation holes of the unit holder and the ventilation amount determined by the opening ratio of the opening expansion portion are created according to the desired acoustic characteristics, there is an effect that the above modules having different acoustic characteristics can be prepared in advance.</p>

Examples of the present invention will be described below with reference to the accompanying drawings.

1 and 2 are configuration diagrams of an embodiment of the insert type headphones according to the present invention, FIG. 1 is a vertical cross-sectional view taken along line I-I of FIG. 2, and FIG. 2 is a cross section taken along line II-II of FIG. It is a top view.

In FIGS. 1 and 2, a substantially disk-shaped driver unit 10 including a diaphragm and a magnetic circuit for driving the diaphragm and having a step portion, and a substantially cylindrical shape having an inner flange at one end and surrounding the outer periphery of the driver unit 10. In addition, for example, a unit holder 20 made of metal, a ring-shaped ventilation resistor 30 arranged between the step portion of the driver unit 10 and the inner flange of the unit holder 20, and the unit holder 20 and the ventilation resistor 30. The front housing body 50, which forms a half of the housing for mounting the combined driver unit 10 and accommodating the headphones, is modularized as described in detail later and constitutes the main part of the insert-type headphones of the present invention. To do. An exploded perspective view of these parts is shown in FIG.

The driver unit 10 includes a diaphragm 11 whose cross section is shown in FIG. 1, a protector plate 12 having a sound emitting opening 13 that protects the sound emitting side and allows the emitted sound to pass through, and a back side of the diaphragm 11. It forms a part of the magnetic circuit that electromagnetically drives the diaphragm, and is composed of a yoke plate 14 having a step portion 16 on the back side adjacent to the outer peripheral end wall while holding the outer circumference of the diaphragm 11 by the outer peripheral end wall. .. Here, as a feature of the present invention, the yoke plate 14 is provided with slits 15 extending from the outer peripheral end wall at least one place over the entire length of the outer peripheral end wall, preferably toward the step portion 16.

The ring-shaped ventilation resistor 30 controls the resistance to ventilation, that is, the ventilation resistance, for example, by heat-press molding a urethane foam sheet to obtain a sheet having a desired thickness and compression ratio. The ventilation resistor 30 is joined to and held by the step portion 16 of the yoke plate 14 by the inner flange 22 of the unit holder 20. At the same time, the substantially cylindrical outer peripheral wall 21 of the unit holder 20 extends along the outer peripheral surface of the ventilation resistor 30 and the outer peripheral end wall of the yoke plate 14 continuous thereto, and extends the front end of the outer peripheral end wall of the yoke plate 14 on the sound emitting side. It is joined to the outer peripheral surface of the pedestal portion 51 of the receiving front housing body 50. Since the flange 22 of the unit holder 20 is provided with a plurality of ventilation holes 23 at substantially equal intervals, air or sound from the sound emitting space passing through the slit 15 of the yoke plate 14 is subjected to ventilation resistance by the ventilation resistor 30. Exit from the rear vent 23 to the back space. Desirably, the flange 22 of the unit holder 20 has a vent slot or a vent extension 26 with a central opening 25 extending in the circumferential direction of the flange at a position corresponding to the slit 15 of the yoke plate 15. By changing the number of these ventilation holes 23 of the flange 22 or the diameter of each hole or the opening ratios of all the ventilation holes 23 and the slot 26, the amount of ventilation from the slit 15 is controlled, and the ventilation resistance of the ventilation resistor 30 is also changed. The desired air volume can be set to set the desired acoustic characteristics.

The front housing body 50 is formed of plastic, for example, in a substantially T-shape in cross section including a substantially disk-shaped pedestal portion 51 and a substantially tubular sound emitting portion 52, and the yoke plate 14 of the driver unit 10 is formed at the rear end surface 53. The pedestal portion 51 that receives the front end surface of the outer peripheral end wall of the driver unit 10 faces forward from the opening portion that opposes the diaphragm protector plate 12 of the driver unit 10 through a gap, that is, when the headphones are worn in the user's ear canal. It is formed integrally with the sound emitting portion 52 extending in a tubular shape toward the entrance of the external auditory canal.

Further, preferably, the outer peripheral wall 21 of the unit holder 20 is provided with a slit 27 for positioning at a position corresponding to the slit 15 of the yoke plate 14, and the pedestal portion 51 of the front housing body 50 is the outer periphery of the received driver unit 10. A protrusion 54 that engages with a positioning slit 27 is provided on a part of the outer peripheral wall surrounding the outer periphery of the edge portion of the unit holder 20. It is desirable that the protrusion 54 be formed in a shape and size that engages not only the slit 27 of the unit holder 20 but also at least a part of the ventilation slit 15 of the driver unit 10 that matches the slit 27. The slit 27 and the engaging protrusion 54 may be provided at a position independent of the position of the ventilation slit 15 if the purpose is merely to position the unit holder 20 and the front housing body 50, but the slit 27 and the engagement protrusion 54 may be provided at a position independent of the position of the ventilation slit 15. By providing it at a position consistent with the slit 15, the assembly of the driver unit 10 incorporating the ventilation resistor 30 and the unit holder 20 and the front housing body 50 constitutes a module having a predetermined ventilation function.

The front housing body 50 further comprises a flexible ear pad 70 that surrounds the outer circumference of the tubular sound emitting portion 52. For example, this ear pad 70 made of an elastic material such as rubber has a tubular portion and its tip that fit the inward protrusion 71 at the rear end into the groove 56 on the outer periphery of the sound emitting portion 52 and project and fix it from the tip of the sound emitting portion. It is a spherical part that extends from to near the front of the cradle, and when the sound emitting part 52 is inserted into the ear canal, it is joined to the peripheral surface of the ear canal to allow the headphones to be worn stably, and it is suitable between the sound emitting part and the ear canal. Seal in.

The front housing body 50 also has a concave outer circumference that receives the protector plate 12 that bulges toward the sound emitting side of the driver unit inside from the rear end surface 53 of the pedestal portion 51 that receives the front end surface of the outer circumference of the yoke plate 14 through a gap. In the portion, a ventilation groove 55 is provided at a position corresponding to the slit 15 on the outer circumference of the driver unit 10, and the tip opening of the tubular sound emitting portion 52 is covered with a protective screen 80 to prevent dust and the like from entering.

The rear housing body 40 that partitions the back space is made of, for example, plastic, and has a substantially hemispherical shape having a front end edge that abuts and engages with the rear end edge of the outer peripheral wall of the front housing body 50 that covers the outer periphery of the front end of the unit holder 20. A bushing 90 made of an elastic material that leads out a cord for a drive circuit is inserted into a hole provided in a part of the rear part of the rear space 41 that is formed and partitioned inside the rear space 41. The bushing 90 is relatively long to maintain some airtightness by increasing the contact surface with the cord surface, while near the front edge of the rear housing body 40, here in the vent 22 of the unit holder 20 of the driver unit. By providing a plurality of slits 42 at close positions, the back space 41 is communicated to the outside.

The front housing body 50 and the rear housing body 40 are connected by a coupling cover 60 that covers the pedestal portion 51 of the front housing body 50 and the outer periphery of the front end edge of the rear housing body 40. The inner flange 61 provided at the front end of the substantially tubular coupling cover 60 is applied to the front end surface of the pedestal portion 51 of the front housing body, and the hook 62 provided on the inner surface on the rear end side is attached to the slit 42 of the rear housing body. The housing bodies 40 and 50 are joined to each other to form a housing by elastically engaging with the ridge 43 provided on the front side of the housing.

In the insert-type headphones of the present invention configured in this way, the sound emitting space that is sealed by mounting the sound emitting portion 52 whose outer circumference is covered with the ear pad 70 in the user's ear canal is basically a driver. A slit 15 provided over at least the entire length of the outer peripheral end wall of the yoke plate 14 of the unit 10 is used as a communication passage to communicate with the rear space communicating with the outside of the back surface of the driver unit 10. In this embodiment, the gap between the pedestal portion 51 of the front housing body 50 and the protector plate 12 of the driver unit 10, the communication groove 55 of the pedestal portion 51, the slit 15, the ventilation resistor 30, and the ventilation resistor 30 are used. The ventilation holes 23 and the ventilation expansion part 26 of the unit holder 20 ensure that the communication passages of both spaces are formed, and the sound emitting space is the ventilation resistance of the ventilation resistance body 30 included in this communication passage and the ventilation opening ratio of the unit holder 20. It communicates with the back space and the external space with the ventilation ratio determined by.

FIG. 6 shows a comparison between the insert type headphones according to the present invention and the sound pressure frequency characteristics of the conventional example. The thick curve A is the present invention and the thin curve B is the conventional example. As is clear from the figure, the headphones according to the present invention not only show a remarkable improvement in the low range as compared with the conventional product, but also improve the sound pressure from the midrange to the high range.

As described above, the insert type headphone according to the present invention has the sound emitting opening 13 as described in claim 1 and protects the sound emitting side of the front surface of the diaphragm 11 and the back side of the diaphragm. A driver unit 10 including a yoke plate 14 that constitutes a part of the diaphragm drive circuit and protects the outer periphery of the diaphragm with an outer peripheral end wall, a sound emitting space in front of the protector plate that accommodates the driver unit, and the outside behind the yoke plate. It is equipped with a housing that partitions the back space that communicates with the rear space, and a communication passage that communicates the sound emitting space that is sealed when the headphones are attached to the ear canal to the back space via a ventilation resistor 30, and the communication passage is the yoke of the driver unit. It consists of a slit 15 provided on the outer peripheral end wall of the plate, and the ventilation resistor 30 blocks the back space side of the slit 15, so that the sound is prevented from being generated in the sound emitting space, and the entire sound from bass to treble is prevented. The frequency characteristics can be improved in the sound range.

<figref num="1">A vertical cross-sectional view showing the configuration of an embodiment of the insert-type headphones according to the present invention.</figref><figref num="2">Cross-sectional view of the configuration in the embodiment of FIG.</figref><figref num="3">An exploded perspective view of the main components that make up the module in the configuration of the embodiment shown in FIG.</figref><figref num="4">Longitudinal sectional view of the front housing body used in the embodiment of FIG.</figref><figref num="5">Top view of the unit holder used in the embodiment of FIG.</figref><figref num="6">Sound pressure frequency characteristic diagram of the insert type headphones in the embodiment of FIG.</figref>

Code description

10 Driver Unit 14 Yoke Plate 15 Slit 20 Unit Holder 23 Vent 26 Ventilation Expansion 27 Slit 30 Ventilation Resistor 40 Rear Housing Body 42 Slit 50 Front Housing Body 51 Cradle 52 Sound Discharge 60 Coupling Cover 70 Ear Pads