headphone

Abstract

To provide canal type headphones capable of stably introducing external sound into a sound guide tube while adjusting bass tone quality.SOLUTION: Headphones according to the present invention are canal type headphones. The headphones comprise driver units, housings, sound guide tubes, and earpieces. The housing is provided with a first chamber storing the driver unit, a second chamber physically separated from the first chamber in the housing, and an introduction hole communicating between the second chamber and the outside of the housing to introduce sound outside the housing into the second chamber. The sound guide tube has a first sound guide communicating with the first chamber, a second sound guide communicating with the second chamber, a wall placed between the first sound guide and the second sound guide, and a sound coupling part communicating with the first sound guide and the second sound guide. The sound guide tube communicates with the first chamber and the second chamber.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to headphones. [Background technology]

[0002] In-ear headphones (earphones) have earpieces that are inserted into the ear canal. The earpieces conform to the shape of the ear canal and deform to fit tightly against the inner surface of the ear canal, sealing the ear canal. Therefore, in-ear headphones have the advantages of being difficult to remove from the ear, having high sound insulation, little sound leakage, and good low-frequency sound quality (frequency characteristics). As a result, in-ear headphones are widely used when going out.

[0003] Moreover, in recent years, wireless in-ear headphones that connect to music players using Bluetooth (registered trademark) have become widespread, and in-ear headphones are now also used during exercise such as walking, jogging (running), and training.

[0004] However, due to the high sound insulation of canal-type headphones, users of the canal-type headphones have difficulty hearing external sounds (for example, environmental sounds outside the headphones, such as the sounds of cars or bicycles running) and therefore are unaware of the approach of a car or bicycle. Therefore, there is a demand for canal-type headphones that have the function of introducing external sounds (introducing external sounds to the user's eardrums).

[0005] For example, a canal-type headphone equipped with a microphone for picking up external sounds and a circuit for processing signals from the microphone may have a function for introducing external sounds. However, this configuration causes problems such as feedback, an increase in the size of the housing, and an increase in cost.

[0006] Also, for example, a hole for introducing external sound is provided in the path of sound waves from the driver unit of the canal type headphones to the earpiece, so that the canal type headphones can have a function of introducing external sound. However, the diffraction angle of the sound waves from the driver unit increases as the frequency of the sound waves decreases (the wavelength of the sound waves increases). Therefore, in this configuration, the sound waves from the driver unit are emitted to the outside through the hole before heading toward the ear canal. As a result, the sound pressure of the low frequency range (about 1 kHz or less) becomes more difficult to transmit to the eardrum as the frequency decreases. That is, in the frequency characteristics of the canal type headphones, the sound pressure level of the low frequency range decreases as the frequency decreases. In other words, if a hole for introducing external sound is provided in the above-mentioned path, the sound quality of the low frequency range of the canal type headphones deteriorates. In this way, there is a trade-off relationship between the introduction of external sound through the hole and the sound quality of the low frequency range.

[0007] A technique has been proposed to adjust the sound quality in the low range by providing a passage in a sound guide tube that is open to the outside air and changing the density of an acoustic resistance material arranged in the passage (see, for example, Patent Document 1).

[0008] According to the technology disclosed in Patent Document 1, the canal-type headphones can introduce external sounds through a passage that is connected to the outside air. However, in this configuration, an opening (air vent) that is connected to the outside air is arranged in the sound guide tube. Therefore, when the canal-type headphones are worn, the air vent is arranged deep inside the concha (near the ear canal). Since the concha cavity is covered by the housing of the canal-type headphones, external sounds cannot reach the air vent unless they pass through a gap between the housing and the auricle (concha cavity). In addition, since the shapes of human ears vary, the air vent can be blocked by the ear canal or the concha cavity. As a result, the external sounds are attenuated or blocked before they reach the air vent. Therefore, in this technology, external sounds are not stably introduced into the sound guide tube, and the sound pressure of the external sounds guided to the user's eardrum varies. In other words, the user cannot clearly hear the external sounds. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 6508687 Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a canal-type headphone that has a desired low-frequency sound quality and is capable of stably introducing external sound into the sound guide tube. [Means for solving the problem]

[0011] The headphones of the present invention are canal-type headphones that are fitted in the user's ear canal and comprise a driver unit that generates sound waves based on an electrical signal, a housing that accommodates the driver unit, a sound guide tube that protrudes from the housing and guides sound waves from the driver unit to the ear canal, and an earpiece that is attached to the sound guide tube and can be deformed to fit the shape of the ear canal, wherein the housing comprises a first chamber in which the driver unit is accommodated, a second chamber within the housing that is physically isolated from the first chamber, and an introduction hole that connects the second chamber to the outside of the housing and introduces external sound from the housing into the second chamber, and the sound guide tube comprises a first sound guide portion that communicates with the first chamber, a second sound guide portion that communicates with the second chamber, a wall portion that is arranged between the first sound guide portion and the second sound guide portion, and an acoustic connecting portion that communicates with each of the first sound guide portion and the second sound guide portion, and the sound guide tube communicates with each of the first and second chambers. Effect of the Invention

[0012] According to the present invention, a desired low-frequency sound quality can be obtained, and external sound can be stably introduced into the sound guide tube. [Brief description of the drawings]

[0013] [Figure 1] 1 is a perspective view showing an embodiment of a headphone according to the present invention. [Diagram 2] 2 is a view taken along the arrow A of a first sound emitting unit included in the headphones of FIG. 1. [Diagram 3] 3 is a cross-sectional view of the first sound emitting unit taken along line BB in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view of the first sound emitting unit in FIG. 3, with the driver unit included in the first sound emitting unit not shown. [Diagram 5] 3 is a perspective view of the first sound emitting unit of FIG. 2 when the first sound emitting unit is worn by a user, as viewed from the front direction of the user. [Figure 6] 6 is a cross-sectional view taken along line BB in FIG. 2 in the state shown in FIG. 5. [Figure 7] 3 is a graph showing frequency characteristics of headphones when the volume of a second chamber included in the first sound emitting unit of FIG. 2 is changed. [Figure 8] 3 is a graph showing frequency characteristics of headphones when the introduction hole of the first sound output unit in FIG. 2 is covered from the outside with a damper and the density of the damper is changed. [Figure 9] FIG. 11 is a schematic cross-sectional view showing another embodiment of the headphones according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of a headphone (earphone) according to the present invention will be described with reference to the drawings. In each drawing, the same members and elements are given the same reference numerals, and duplicated explanations will be omitted.

[0015] ●Headphones● Headphone configuration FIG. 1 is a perspective view showing an embodiment of a headphone according to the present invention.

[0016] The headphones 1 are worn on the ear (ear canal) of a user U of the headphones 1 (see FIG. 5; the same applies below), and output sound waves corresponding to audio signals from a sound source (not shown; the same applies below), such as a portable music player. The headphones 1 include a first sound emitting unit 10 and a second sound emitting unit 20. The headphones 1 are connected to the sound source via a wireless communication line. The first sound emitting unit 10 and the second sound emitting unit 20 are also connected via a wireless communication line. In other words, the headphones 1 are completely wireless headphones.

[0017] The headphones are not limited to completely wireless headphones. That is, for example, the headphones may be wireless headphones in which the first sound emitting unit and the second sound emitting unit are connected by a cable, or may be wired headphones that are connected to a sound source via a cable.

[0018] The first sound emitting unit 10 is attached to the right ear (ear canal) of a user U, and outputs sound waves corresponding to an audio signal from a sound source.

[0019] The second sound emitting unit 20 is attached to (the ear canal of) the left ear of the user U, and outputs sound waves corresponding to an audio signal from a sound source.

[0020] ● Configuration of the first sound emission unit FIG. 2 is a view of the first sound emitting unit 10 in FIG. FIG. 3 is a cross-sectional view of the first sound emitting unit 10 taken along line BB in FIG. Fig. 4 is a cross-sectional view of the first sound emitting unit 10 in a state in which the driver unit 12 is not shown in Fig. 3. For convenience of explanation, Fig. 3 shows a diaphragm 121, which will be described later, by a two-dot chain line.

[0021] The first sound emitting unit 10 includes a housing 11, a driver unit 12, a sound guide tube 13, an earpiece 14, and a circuit board 15.

[0022] The housing 11 contains the driver unit 12 and the circuit board 15. The housing 11 is made of a synthetic resin such as ABS. The housing 11 includes a main body 111, a protruding portion 112, a partition wall 113, a first chamber R1, a second chamber R2, a third chamber R3, and an introduction hole 11h.

[0023] "Housing the driver unit 12" includes a state in which the entire driver unit 12 is disposed within the housing 11 and a state in which only a portion of the driver unit 12 is disposed within the housing 11.

[0024] The main body 111 is hollow and generally egg-shaped. When the first sound emitting unit 10 is worn by the user U (hereinafter referred to as the "worn state"), a part of the main body 111 protrudes from another part of the main body 111 toward the ear canal in a generally hollow truncated cone shape, and is configured as a protruding part 112.

[0025] In the following description, the direction in which protrusion 112 protrudes from main body 111 (to the right in FIG. 3) is referred to as the "front" and the opposite direction (to the left in FIG. 3) is referred to as the "rear".

[0026] In addition, in the following description, the "cross-sectional area of ​​a path" means the opening area of ​​the path when the path is cut by a plane perpendicular to the direction of air flow passing through the path in the shortest distance from one opening of the path to the other opening of the path.

[0027] The partition wall 113 physically separates the inside of the main body portion 111 and the inside of the protruding portion 112 into a first chamber R1 and a second chamber R2 within the housing 11. The partition wall 113 includes a first partition wall 113a and a second partition wall 113b.

[0028] The first partition wall 113a has a plate shape parallel to the front-rear direction. The first partition wall 113a is disposed inside the protruding portion 112. The first partition wall 113a is integral with the protruding portion 112. The first partition wall 113a is disposed forward of the introduction hole 11h in the front-rear direction.

[0029] The second partition wall 113b is an L-shaped plate having a first portion 113b1 along the front-rear direction and a second portion 113b2 along the penetrating direction of the introduction hole 11h. The second partition wall 113b is disposed on the inner side of the main body portion 111 and the protruding portion 112. The second partition wall 113b is separate from the main body portion 111 and the protruding portion 112. The second partition wall 113b is welded to the inner surface of the main body portion 111 and the protruding portion 112 so that the first portion 113b1 is continuous with the first partition wall 113a.

[0030] The first chamber R1 houses the driver unit 12. The first chamber R1 is a room formed by the main body portion 111, the protruding portion 112, the isolation wall 113, and the circuit board 15.

[0031] The second chamber R2 is a path that guides the external sound from the introduction hole 11h to the sound guide tube 13, and adjusts the low-frequency sound quality (frequency characteristics) of the first sound emission unit 10, as described later. The second chamber R2 is a room formed by the main body 111, the protruding portion 112, and the isolation wall 113. The second chamber R2 is physically isolated from the first chamber R1 by the isolation wall 113.

[0032] "External sound" refers to sound waves of environmental sounds (e.g., the sound of a car or bicycle running on the road, the sound of a car engine, announcements output from a speaker, etc.) output from sound sources outside the housing 11 (e.g., a car or bicycle running on the road, or speakers installed indoors or outdoors).

[0033] The third chamber R3 accommodates a circuit (not shown) (described later) mounted on the circuit board 15. The third chamber R3 is a chamber formed by the main body 111 and the circuit board 15.

[0034] In this embodiment, the volume of the first chamber R1 is sufficiently larger than the volumes of the second chamber R2 and the third chamber R3. The volume of the second chamber R2 is also larger than the volume of the sound conduit 13.

[0035] The introduction hole 11h is a circular through hole that introduces external sound into the second chamber R2. The introduction hole 11h is disposed in the main body 111, and connects the outside of the housing 11 to the second chamber R2. The through direction of the introduction hole 11h is perpendicular to the protruding direction (front-rear direction) of the protruding portion 112.

[0036] The driver unit 12 generates and outputs sound waves based on an electric signal from a sound source. The driver unit 12 is a balanced armature type driver unit. The driver unit 12 includes a diaphragm 121 that vibrates based on an electric signal from the sound source. The driver unit 12 is attached between the protruding portion 112 and the first isolation wall 113a. That is, the driver unit 12 is housed in the protruding portion 112 of the first chamber R1. In the front-rear direction, the driver unit 12 is disposed forward of the introduction hole 11h. In other words, the introduction hole 11h is disposed forward of the driver unit 12 (diaphragm 121).

[0037] When the headphones are worn, the sound conduit 13 guides sound waves (hereinafter referred to as "reproduced sound") from the driver unit 12 toward the ear canal. The sound conduit 13 is integrated with the housing 11. The sound conduit 13 includes a cylindrical tubular portion 131, a plate-shaped wall portion 132, a first sound guiding portion 133, a second sound guiding portion 134, and an acoustic coupling portion 135.

[0038] The cylindrical portion 131 is formed by a front end surface of the protruding portion 112 protruding forward in a cylindrical shape.

[0039] The wall portion 132 physically separates the inside of the cylindrical portion 131 into the first sound guiding portion 133 and the second sound guiding portion 134. The wall portion 132 is a plate-like portion that is integral with both the cylindrical portion 131 and the first isolation wall 113a. The wall portion 132 is disposed between the first sound guiding portion 133 and the second sound guiding portion 134 on the inside of the rear half of the cylindrical portion 131.

[0040] The first sound guiding section 133 communicates with the first chamber R1 and guides the reproduced sound to the acoustic coupling section 135. The first sound guiding section 133 is a semi-cylindrical passage formed by the tubular section 131 and the wall section 132. The first sound guiding section 133 includes a groove section 133a. The groove section 133a is a groove in which the front end section of the driver unit 12 is disposed. The groove section 133a is semi-cylindrical along the front-rear direction and is disposed on the inner surface of the tubular section 131. The groove section 133a extends from the front end of the first sound guiding section 133 to the front end section of the protruding section 112. With this configuration, even if the driver unit 12 is disposed between the protruding section 112 and the rear end section of the sound guiding tube 13, the outer diameters of the protruding section 112 and the sound guiding tube 13 can be made small enough to be inserted into the ear canal. Also, a part of the reproduced sound is guided to the acoustic coupling section 135 via the groove section 133a.

[0041] The second sound guiding section 134 communicates with the second chamber R2 and guides the outside sound from the introduction hole 11h to the acoustic coupling section 135. The second sound guiding section 134 is a semi-cylindrical passage defined by the tubular section 131 and the wall section 132. The cross-sectional area of ​​the second sound guiding section 134 is smaller than the cross-sectional area of ​​the first sound guiding section 133, the opening area of ​​the introduction hole 11h, and the cross-sectional area of ​​the second chamber R2. The volume of the second sound guiding section 134 is smaller than the volume of the first sound guiding section 133 and the volume of the second chamber R2.

[0042] The acoustic coupling section 135 communicates with each of the first sound guiding section 133 and the second sound guiding section 134, and acoustically couples (combines) the reproduced sound and the external sound and guides them toward the ear canal. The acoustic coupling section 135 is disposed in the front half of the sound guiding tube 13.

[0043] When worn, earpiece 14 deforms to fit the shape of the ear canal and fits tightly against the inner surface of the ear canal. Earpiece 14 is made of synthetic resin such as elastic silicone rubber. Earpiece 14 includes a substantially cylindrical inner tube portion 141 and an umbrella-shaped outer tube portion 142 that is integral with inner tube portion 141. Earpiece 14 is attached to sound conduit 13 by inserting tube portion 131 into inner tube portion 141. Earpiece 14 is detachable from sound conduit 13.

[0044] The circuit board 15 mounts circuits (such as a wireless communication circuit, a D / A conversion circuit, and an amplifier circuit) necessary for the operation of the first sound emitting unit 10. The circuit board 15 is housed in the main body 111 so as to separate the first chamber R1 and the third chamber R3.

[0045] ● Configuration of the second sound emission unit Return to Figure 1. The second sound emitting unit 20 includes a housing 21, a driver unit (not shown), a sound guide tube (not shown), an earpiece 24, and a circuit board (not shown). The housing 21 includes an introduction hole 21h. The configuration of the second sound emitting unit 20 is the same as the configuration of the first sound emitting unit 10. Therefore, a detailed description of the second sound emitting unit 20 will be omitted.

[0046] In the headphones 1 configured as above, when worn, the earpiece 14 is inserted into the ear canal of the right ear of the user U, and the earpiece 24 is inserted into the ear canal of the left ear of the user U. In other words, the headphones 1 are canal-type headphones that are worn in the ear canal.

[0047] ●Headphone operation Next, the operation of the headphones 1 will be described with reference to the drawings, taking the first sound emitting unit 10 as an example.

[0048] FIG. 5 is a perspective view of the first sound emitting unit 10 when worn by a user U, as viewed from the front direction of the user U. FIG. Fig. 6 is a cross-sectional view taken along line BB in Fig. 2 in the state of Fig. 5. In Fig. 6, the head of a user U is shown by a two-dot chain line.

[0049] When the first sound emission unit 10 is attached, the outer cylinder portion 142 of the earpiece 14 is inserted into the ear canal, deformed to fit the shape of the ear canal, and comes into close contact with the inner surface of the ear canal. At this time, a part of the air pushed into the ear canal by the earpiece 14 is discharged from the introduction hole 11h to the outside of the housing 11 via the inner cylinder portion 141, the acoustic coupling portion 135, the second sound guide portion 134, and the second chamber R2. Therefore, the sense of pressure and blockage in the ear canal given to the user U when wearing the headphones 1 is reduced compared to the case where the air in the ear canal is not discharged to the outside of the housing 11.

[0050] In the wearing state, the reproduced sound is guided to the eardrum (not shown, the same applies below) via the first sound guide portion 133, the acoustic coupling portion 135, the inner tube portion 141, and the ear canal, as shown by the thick solid arrow S1 in FIG. 6. As a result, the user U in the wearing state can hear the desired sound (reproduced sound) from the sound source. On the other hand, the outside sound is guided to the eardrum via the introduction hole 11h, the second chamber R2, the second sound guide portion 134, the acoustic coupling portion 135, the inner tube portion 141, and the ear canal, as shown by the solid arrow S2 in FIG. 6. As a result, the user U in the wearing state can hear the outside sound. In this way, the reproduced sound and the outside sound each pass through the acoustic coupling portion 135. That is, the outside sound is acoustically coupled (combined) with the reproduced sound in the acoustic coupling portion 135 (and / or the inner tube portion 141) and guided to the eardrum.

[0051] Here, the diffraction angle of a sound wave is smaller as the wavelength of the sound wave is shorter. Therefore, high-frequency sound waves have high linearity. On the other hand, low-frequency sound waves have high diffusion properties. Therefore, among the sound waves guided to the first sound guiding section 133, low-frequency sound waves (approximately 1 kHz or less) are diffracted within the acoustic coupling section 135 and more easily enter the second sound guiding section 134 as the wavelength of the sound wave becomes longer (the frequency of the sound wave becomes lower).

[0052] The low-frequency sound waves that have entered the second sound guide section 134 are released to the outside of the housing 11 through the second chamber R2 and the introduction hole 11h, as shown by the dashed arrow S3 in FIG. 6. Therefore, among the frequency characteristics of the headphones 1, the low-frequency sound pressure level (low-frequency sound quality) decreases as the frequency of the sound waves decreases. Therefore, among the external sounds synthesized in the acoustic coupling section 135, the low-frequency external sounds are guided to the eardrum without being canceled (masked) by the sound waves from the driver unit 12 as the frequency of the external sounds decreases. Generally, external sounds that notify pedestrians and runners (those who are running or jogging) of the presence of danger are the running sounds of cars and bicycles, and the engine sounds of cars. The frequency band of these external sounds is a low range of about 100 Hz to 250 Hz. Therefore, a user U wearing the headphones can listen to the running sounds of cars and engine sounds while listening to playback sounds such as vocals while going out.

[0053] In the first sound emitting unit 10, the sound pressure level of the low frequency range is affected by the air path (hereinafter referred to as the "air passage L") between the outside of the housing 11 and the acoustic coupling part 135. That is, the sound pressure level of the low frequency range can be adjusted to a desired sound pressure level by changing the size (opening area, length, volume, etc.) of the air passage L. In this embodiment, the air passage L is composed of the introduction hole 11h, the second chamber R2, and the second sound guiding part 134.

[0054] Since the volume of the second chamber R2 is sufficiently larger than the volume of the second sound guide 134, the volume of the air passage L can be easily changed simply by changing the volume of the second chamber R2. Furthermore, since the volume of the housing 11 is sufficiently larger than the volume of the sound guide 13, the range in which the volume of the second chamber R2 can be changed is large. As described above, the second separating wall 113b is separate from both the main body 111 and the protruding portion 112. Therefore, the volume of the second chamber R2 can be easily changed simply by changing the shape of the second separating wall 113b.

[0055] As described above, both the reproduced sound and the external sound pass through the air passage L. Therefore, the reproduced sound and the external sound passing through the air passage L are each influenced by the air in the air passage L. Here, the volume of the second chamber R2 occupies most of the volume of the air passage L. Therefore, the reproduced sound and the external sound passing through the air passage L are each strongly influenced by the volume of the second chamber R2 (i.e., the air in the second chamber R2). That is, for example, when the volume of the second chamber R2 is sufficiently larger than the volume of the second sound guide portion 134 and the volume of the introduction hole 11h, the stiffness of the air in the second chamber R2 is small. That is, the larger the volume of the second chamber R2, the smaller the effect that the volume of the second chamber R2 has on the reproduced sound and the external sound. In other words, the smaller the volume of the second chamber R2, the greater the effect. Thus, in the headphones 1, the second chamber R2 has an acoustic effect on each of the reproduced sound and the external sound. That is, the second chamber R2 adjusts the intake of external sounds in the low frequency range and adjusts the quality of low frequencies of the headphones 1.

[0056] 7 is a graph showing the frequency characteristics of the headphones 1 when the volume of the second chamber R2 is changed. In this figure, the vertical axis shows the sound pressure level, and the horizontal axis shows the frequency. In this figure, the solid line shows the frequency characteristics of the headphones 1 of this embodiment, and the dashed line shows the frequency characteristics when the volume of the second chamber R2 is smaller than that of this embodiment.

[0057] As shown in FIG. 7, when the volume of the second chamber R2 is reduced, the sound pressure level in the low range increases in the frequency characteristics of the headphones 1. In this embodiment, the positions and sizes of the introduction hole 11h and the second sound guide portion 134 are constant. Therefore, the volume of the second chamber R2 can be changed by changing the shape of the second isolation wall 113b. When the volume of the second chamber R2 is reduced by changing the shape of the second isolation wall 113b, the acoustic impedance of the second chamber R2 with respect to the reproduced sound increases, and the second chamber R2 functions as an acoustic barrier. As a result, the sound pressure level of the reproduced sound in the low range increases.

[0058] Returning to Figures 5 and 6. As described above, the introduction hole 11h is a through hole penetrating the main body 111. Therefore, the opening area of ​​the introduction hole 11h (air permeability of the introduction hole 11h) can be changed simply by covering the introduction hole 11h from the outside of the housing 11. In addition, the air permeability of the introduction hole 11h can be changed by changing the density of the member covering the introduction hole 11h.

[0059] 8 is a graph showing the frequency characteristics of the headphones 1 when the introduction hole 11h is covered with a member (not shown) from the outside of the housing 11 and the density of the member is changed. In the figure, the solid line shows the frequency characteristics when the introduction hole 11h is not covered (when there is no member), the two-dot chain line shows the frequency characteristics when the introduction hole 11h is completely sealed, the dashed line shows the frequency characteristics when the density of the member is low, and the one-dot chain line shows the frequency characteristics when the density of the member is high. The figure shows that the sound pressure level in the low range increases as the air permeability of the introduction hole 11h decreases.

[0060] Returning to Figures 5 and 6. In the worn state, the introduction hole 11h is disposed at a position that is outside the cavity of the concha of the user U and visible from the front of the user U. In other words, in the worn state, the introduction hole 11h is not blocked (covered) by the ear of the user U. Therefore, the introduction hole 11h can always introduce external sound into the second chamber R2.

[0061] "Outside the cavity of the concha" means outside the tragus (left side of the paper in Fig. 5 and Fig. 6). That is, in this embodiment, the introduction hole 11h is disposed outside the tragus in the auricle.

[0062] Summary According to the embodiment described above, the housing 11 includes a first chamber R1 in which the driver unit 12 is accommodated, a second chamber R2 physically isolated from the first chamber R1, and an introduction hole 11h that connects the second chamber R2 to the outside of the housing 11 and introduces external sound into the second chamber R2. The sound guide tube 13 communicates with each of the first chamber R1 and the second chamber R2. According to this configuration, sound waves (reproduced sound) from the driver unit 12 are guided to the sound guide tube 13 via the first chamber R1. Meanwhile, external sound is guided to the sound guide tube 13 via the introduction hole 11h and the second chamber R2. As a result, the external sound is acoustically coupled (combined) with the reproduced sound in the sound guide tube 13 and guided to the eardrum of the user U. In addition, low-frequency sound waves of the reproduced sound are emitted to the outside of the housing 11 via the second chamber R2 and the introduction hole 11h. As a result, the sound pressure level of the low frequency range of the headphones 1 decreases.

[0063] Here, the second chamber R2 has an acoustic effect on both the reproduced sound and the external sound. That is, the reproduced sound released to the outside and the external sound introduced into the sound guide tube are affected by the air (volume) in the second chamber R2. Also, as described above, the ventilation rate of the introduction hole 11h affects the sound pressure level of the low range. As a result, the sound pressure level of the low range of the headphones 1 is adjusted to a desired sound pressure level by the volume of the second chamber R2 and / or the ventilation rate of the introduction hole 11h. That is, the sound quality of the low range of the headphones 1 is adjusted to a desired sound quality by the volume of the second chamber R2 and / or the ventilation rate of the introduction hole 11h. In this way, the headphones 1 have a desired low range sound quality due to the second chamber R2, and can stably introduce external sound into the sound guide tube 13 by the introduction hole 11h of the housing 11. Therefore, the user U in the wearing state can clearly hear the reproduced sound and the external sound.

[0064] According to the embodiment described above, the sound guide tube 13 includes the first sound guide portion 133 communicating with the first chamber R1, the second sound guide portion 134 communicating with the second chamber R2, and the wall portion 132 disposed between the first sound guide portion 133 and the second sound guide portion 134. According to this configuration, the reproduced sound is guided to the outlet (the opening of the sound guide tube 13 on the ear canal side) of the sound guide tube 13 without leaking into the second chamber R2 on the way. Then, only low-frequency sound waves of the reproduced sound enter the second sound guide portion 134 branched off at the outlet, and the mid-high frequency sound waves are guided to the ear canal via the earpiece 14. As a result, the headphones 1 do not change the sound pressure of the mid-high frequency range. Moreover, the outside sound is guided to the outlet (front end) of the sound guide tube 13 via the second sound guide portion 134, where it is acoustically coupled (combined) with the reproduced sound and guided to the ear canal. In this way, the headphones 1 have the desired low-frequency sound quality, and can stably introduce external sound to (the outlet of) the sound conduit 13. As a result, the user U wearing the headphones can clearly hear the reproduced sound and external sound.

[0065] Furthermore, according to the embodiment described above, the sound guide tube 13 includes an acoustic coupling section 135 that communicates with each of the first sound guide section 133 and the second sound guide section 134. According to this configuration, only low-frequency sound waves enter the second sound guide section 134 that branches off at the acoustic coupling section 135, and mid- to high-frequency sound waves are guided to the ear canal via the acoustic coupling section 135. As a result, the headphones 1 can adjust only the low-frequency sound pressure without changing the mid- to high-frequency sound pressure. In addition, the outside sound is guided to the acoustic coupling section 135 via the second sound guide section 134, acoustically coupled (combined) with the reproduced sound at the acoustic coupling section 135, and guided to the ear canal. In this way, the headphones 1 have the desired low-frequency sound quality and can stably introduce the outside sound into the sound guide tube 13 (acoustic coupling section 135). As a result, the user U wearing the headphones can clearly hear the reproduced sound and the outside sound.

[0066] Furthermore, according to the embodiment described above, when the direction in which the sound guide tube 13 is arranged relative to the driver unit 12 is defined as the front, the introduction hole 11h is arranged behind the driver unit 12 (diaphragm 121) in the front-rear direction. With this configuration, the introduction hole 11h is arranged at a position farther away from the ear canal than the position in which the driver unit 12 is arranged when the headphones are worn. In other words, the introduction hole 11h is arranged at a position that is less likely to be covered by the auricle of the user U when the headphones are worn. As a result, the headphones 1 can introduce external sounds into the sound guide tube 13 more stably than conventional headphones that have an air hole near the ear canal. Therefore, the user U can clearly hear the reproduced sound and the external sound when the headphones are worn.

[0067] Furthermore, according to the embodiment described above, the housing 11 includes a partition wall 113 that separates the first chamber R1 from the second chamber R2. With this configuration, the second chamber R2 is reliably separated from the first chamber R1 in which the driver unit 12 is housed. The volume (cross-sectional area) of the second chamber R2 can be changed by changing the shape of the partition wall 113. That is, the low-frequency sound pressure level of the headphones 1 can be adjusted to a desired sound pressure level by changing the shape of the partition wall 113. As a result, the headphones 1 have a desired low-frequency sound quality and can stably introduce external sounds into the sound guide tube 13. Therefore, the user U wearing the headphones can clearly hear the reproduced sound and the external sound.

[0068] Furthermore, according to the embodiment described above, the partition wall 113 includes the second partition wall 113b that is separate from each of the main body 111 and the protruding portion 112. According to this configuration, the volume of the second chamber R2 can be easily changed by changing the shape of the second partition wall 113b. Here, for example, when the housing 11 is molded using a mold, the manufacturer of the headphones 1 can mold each of the main body 111, the protruding portion 112, and the first partition wall 113a using a mold, and mold the second partition wall 113b separately. As a result, the manufacturer can change the volume of the second chamber R2 simply by changing the shape of the second partition wall 113b. That is, the low-frequency sound pressure level of the headphones 1 can be easily adjusted to a desired sound pressure level simply by changing the design of the second partition wall 113b. That is, the low-frequency sound quality of the headphones 1 can be easily adjusted.

[0069] Furthermore, according to the embodiment described above, the opening area of ​​the introduction hole 11h is larger than the cross-sectional area of ​​the second sound guide portion 134. In other words, the introduction hole 11h, which is the entrance of the external sound to the second chamber R2, is smaller than the second sound guide portion 134, which is the entrance of the low-frequency sound waves to the second chamber R2. According to this configuration, the headphones 1 can control the low-frequency sound waves entering the second chamber R2 while introducing a large amount of external sound into the second chamber R2. In other words, the headphones 1 have the desired low-frequency sound quality and can stably introduce external sound into the sound guide tube 13. As a result, the user U wearing the headphones can clearly hear the reproduced sound and the external sound.

[0070] Furthermore, according to the embodiment described above, the cross-sectional area of ​​the second chamber R2 is larger than the cross-sectional area of ​​the second sound guide 134 and the opening area of ​​the introduction hole 11h. According to this configuration, the entrance of the outside sound from the second chamber R2 to the second sound guide 134 is controlled by the cross-sectional area (volume) of the second sound guide. On the other hand, the entrance of the reproduced sound from the second chamber R2 to the introduction hole 11h is controlled by the opening area of ​​the introduction hole 11h. In other words, the low-frequency sound quality of the headphones 1 and the introduction of the outside sound are adjusted by the size of the air passage L. Therefore, the headphones 1 have the desired low-frequency sound quality and can stably introduce the outside sound into the sound guide tube 13. As a result, the user U wearing the headphones can clearly hear the reproduced sound and the outside sound.

[0071] Furthermore, according to the embodiment described above, when the headphones are worn, the introduction hole 11h is disposed in a position visible from outside the housing 11 (for example, outside the cavity of the concha of the user U). With this configuration, the introduction hole 11h is not blocked (covered) from the outside by the ear (auricle). Therefore, the introduction hole 11h can always introduce external sound into the second chamber R2. As a result, the headphones 1 can stably introduce external sound into the sound guide tube 13.

[0072] The number and shape of the introduction holes 11h are not limited to those in the present embodiment. That is, for example, the number of the introduction holes may be multiple, and the introduction holes may be slit-shaped.

[0073] In addition, the arrangement of the introduction hole relative to the driver unit in the front-rear direction is not limited to the present embodiment as long as the introduction hole is not blocked by the ear. That is, for example, the introduction hole may be arranged in the same position as the driver unit in the front-rear direction, or may be arranged further back than the position shown in FIG.

[0074] Furthermore, if external sound can be introduced into the acoustic coupling portion, the opening area of ​​the introduction hole may be equal to or smaller than the cross-sectional area of ​​the second sound guiding portion.

[0075] Furthermore, the penetration direction of the introduction hole may be inclined with respect to the protruding direction (front-rear direction) of the protruding portion.

[0076] Furthermore, the second isolation wall may be integral with both the main body and the protrusion.

[0077] Furthermore, the housing may not have a protrusion, and the sound guide tube may protrude from the main body.

[0078] Furthermore, the sound guide tube may be separate from the housing. In this configuration, the sound guide tube does not have a wall, and the separating wall may extend into the sound guide tube. That is, for example, the first sound guide section and the second sound guide section may each be formed by a sound guide tube and a separating wall.

[0079] Furthermore, the sound guide tube does not have to have a wall. In this configuration, low-frequency sound waves enter the second chamber through the sound guide tube. Also, external sound is combined with the reproduced sound inside the sound guide tube.

[0080] Furthermore, the sound conduit does not have to include an acoustic coupling portion. In this configuration, for example, the wall portion may divide the inside of the sound conduit into a first sound guiding portion and a second sound guiding portion from the rear end to the front end of the sound conduit.

[0081] Furthermore, the headphones may include a support that holds the housing on the user's auricle. In this configuration, the support may be detachable from the housing and rotatable between a closed position that blocks the introduction hole and an open position that does not block the introduction hole. The introduction hole may be blocked (sealed) when the support is attached to the housing and opened when the support is removed from the housing. With this configuration, the user can easily change the sound quality of the low frequencies by changing the position of the support or by attaching and detaching it.

[0082] Furthermore, the driver unit may be a dynamic type driver unit. In this configuration, the driver unit is housed in the main body.

[0083] 9 is a schematic cross-sectional view showing another embodiment of headphones according to the present invention. The figure shows a cross-section of headphones 1A equipped with a dynamic driver unit 12A. For convenience of explanation, the figure shows only a cross-section of a first sound emitting unit 10A equipped in the headphones 1A.

[0084] The headphones 1A include a housing 11A, a driver unit 12A, a sound guide tube 13A, and an earpiece .

[0085] Housing 11A includes introduction hole 11Ah and a separation wall 113A. Separation wall 113A physically separates the inside of housing 11A into a first chamber RA1 that houses driver unit 12A and a second chamber RA2 that guides external sound from introduction hole 11Ah to sound guide tube 13A. Driver unit 12A includes diaphragm 121A.

[0086] The sound guiding tube 13A comprises a first sound guiding portion 133A communicating with the first chamber RA1, a second sound guiding portion 134A communicating with the second chamber RA2, an acoustic coupling portion 135A communicating with each of the first sound guiding portion 133A and the second sound guiding portion 134A, and a wall portion 132A physically separating the first sound guiding portion 133A and the second sound guiding portion 134A.

[0087] When the direction in which the sound guide tube 13A is arranged relative to the driver unit 12A is defined as the front, the introduction hole 11Ah is arranged behind the driver unit 12A in the front-rear direction. According to this configuration, sound waves (reproduced sound) from the driver unit 12A are guided to the acoustic coupling part 135A via the first chamber RA1 and the first sound guide part 133A. Low-frequency sound waves enter the second sound guide part 134A from the acoustic coupling part 135A and are emitted to the outside of the housing 11A via the second chamber RA2 and the introduction hole 11Ah. On the other hand, outside sound is guided to the acoustic coupling part 135A via the introduction hole 11Ah and the second chamber RA2, acoustically coupled (combined) with the reproduced sound in the acoustic coupling part 135A, and guided to the ear canal. That is, the headphones 1A have the desired low-frequency sound quality and can stably introduce external sounds to the sound conduit 13A (acoustic coupling portion 135A) like the headphones 1 described above. As a result, the user U wearing the headphones can clearly hear the reproduced sound and external sounds. [Explanation of symbols]

[0088] 1. Headphones 11. Housing 11h Introduction hole 113 Isolation Wall 113b Second isolation wall (part of isolation wall) 12 Driver unit 121 Diaphragm 13 Sound conduit 132 Wall 133 First sound guide 134 Second sound guide 135 Acoustic connection section 14 Earpiece R1 Room 1 R2 2nd room 1A Headphones 11A Housing 11Ah introduction hole 113A Isolation wall 12A driver unit 121A diaphragm 13A sound conduit 132A Wall section 133A 1st sound guide section 134A Second Sound Conductor 135A Acoustic connection section RA1 Room 1 RA2 Room 2

Claims

1. In-ear headphones that are fitted to the ear canal of a user, A driver unit that generates sound waves based on an electrical signal; a housing that accommodates the driver unit; a sound guide tube that protrudes from the housing and guides the sound waves from the driver unit to the ear canal; an earpiece attached to the sound guide tube and deformable to fit the shape of the ear canal; and The housing includes: A first chamber in which the driver unit is accommodated; a second chamber within the housing, the second chamber being physically isolated from the first chamber; an introduction hole that communicates the second chamber with the outside of the housing and introduces external sound of the housing into the second chamber; With The sound guide tube is a first sound guide portion communicating with the first chamber; a second sound guide portion communicating with the second chamber; a wall portion disposed between the first sound guiding portion and the second sound guiding portion; an acoustic coupling portion communicating with each of the first sound guiding portion and the second sound guiding portion; With The sound guide tube communicates with both the first chamber and the second chamber. The headphone is characterized by:

2. The driver unit includes: a diaphragm that vibrates based on the electrical signal; With When a direction in which the sound guide tube is arranged with respect to the driver unit is defined as a forward direction, the introduction hole is arranged rearward of the diaphragm in a front-rear direction. The headphone according to claim 1.

3. The introduction hole is disposed rearward of the driver unit. The headphone according to claim 2.

4. The housing includes: a partition wall separating the first chamber and the second chamber; Equipped with The headphone according to claim 1.

5. A portion of the isolation wall is separate from the housing. The headphone according to claim 4.

6. the isolation wall extends into the sound guiding tube to form the first sound guiding section and the second sound guiding section within the sound guiding tube. The headphone according to claim 4.

7. an opening area of ​​the introduction hole is larger than a cross-sectional area of ​​the second sound guiding portion; The headphone according to claim 1.

8. a cross-sectional area of ​​the second chamber is larger than a cross-sectional area of ​​the second sound guiding portion and an opening area of ​​the introduction hole, The headphone according to claim 1.

9. The volume of the second chamber is greater than the volume of the sound conduit. The headphone according to claim 8.

10. When the earpiece is attached to the ear canal, the introduction hole is disposed at a position visible from the outside of the housing. The headphone according to claim 1.

11. When the earpiece is attached to the ear canal, the introduction hole is disposed outside the concha cavity of the user. The headphone according to claim 10.

12. the acoustic coupling portion is a space communicating with each of the first sound guiding portion and the second sound guiding portion, The headphone according to claim 1.

13. The acoustic coupling portion is disposed adjacent to the earpiece. The headphone according to claim 1.

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