Earphones

Abstract

To provide earphones with high sound quality, while reducing pressure on a diaphragm.SOLUTION: Earphones 1 comprise: a diaphragm 6; a driver unit 5 which has the diaphragm 6 on its front surface; a unit cap 2 which houses the driver unit 5; and an acoustic tube 3 which is coupled to a front surface of the unit cap 2 and forms a front-side air chamber 3s on a front surface of the diaphragm 6. The unit cap 2 has: a unit holding wall 21 which holds a lateral wall of the driver unit 5; a communication hole 22 which brings the inside of the unit holding wall 21 into communication with the outside thereof and also brings the front surface of the unit cap 2 into communication with a rear surface thereof, in front of the unit holding wall 21. A central axis of a unit housing part 21a defined by the unit holding wall 21 is eccentric with respect to a central axis of the unit cap 2.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] 2. Description of the Related Art Earplug-shaped in-ear headphones (earphones) that are inserted into the ear canal are known.

[0003] Previously, earphones have been known that have, for example, an opening that emits sound waves output from the driver unit into the ear, and that include a sound emitting member that is attached to the edge of the cylindrical support member on the sound emitting side of the driver unit with the outer surface of the cylindrical support member exposed, and a cover member that is attached to the edge of the cylindrical support member opposite the sound emitting side of the driver unit with the outer surface of the cylindrical support member exposed (see, for example, Patent Document 1).

[0004] In earplug-shaped canal-type earphones, a small driver unit can be installed in the ear canal, so by placing the diaphragm close to the eardrum, the loss of low-frequency sounds can be reduced even if the area of ​​the diaphragm is small. On the other hand, since the space between the diaphragm and the eardrum is small, the diaphragm may be deformed or crushed as a result of the pressure applied to the diaphragm when the earphone is inserted into the ear. However, the prior art documents do not disclose any technology that solves this problem. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-158045 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide an earphone that reduces pressure on the diaphragm and produces high-quality sound. [Means for solving the problem]

[0007] The earphones of the present invention comprise a diaphragm, a driver unit having the diaphragm on its front surface, a unit cap that houses the driver unit, and an acoustic tube connected to the front surface of the unit cap and forming a front air chamber on the front surface of the diaphragm, the unit cap comprising a unit retaining wall that holds the side wall of the driver unit, and a communication hole in front of the unit retaining wall that connects the inside and outside of the unit retaining wall and the front and rear surfaces of the unit cap, and the central axis of the unit accommodating portion defined by the unit retaining wall is eccentric from the central axis of the unit cap. Effect of the Invention

[0008] According to the present invention, it is possible to provide earphones that reduce pressure on the diaphragm and produce high quality sound. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic front view of an embodiment of an earphone according to the present invention, showing a state in which a housing is removed. [Diagram 2] FIG. 2 is a schematic vertical cross-sectional view of the earphone. [Diagram 3] FIG. 2 is a schematic bottom view of the earphone. [Figure 4] 2 is a schematic plan view of a housing of the earphone. FIG. [Diagram 5] FIG. 2 is a schematic perspective view of the housing. [Figure 6] 1 is a graph showing frequency characteristics of the above earphone and frequency characteristics of the related art. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of an earphone according to the present invention will be described with reference to the drawings. In the following description, the axial direction of the driver unit 5 is also referred to as the z direction, and the directions perpendicular to the z direction are also referred to as the x direction and the y direction. The surface facing the +z direction is also referred to as the rear surface, and the surface facing the -z direction is also referred to as the front surface.

[0011] ●Earphones● As shown in FIG. 1, the earphone 1 mainly has, in appearance, a unit cap 2, an acoustic tube 3, and a housing 4. The unit cap 2 is a bottomed cylindrical member having a bottom on the front side. The acoustic tube 3 is a substantially cylindrical member connected to the front side of the unit cap 2. The acoustic tube 3 extends obliquely with respect to the axis of the unit cap 2. An air hole 25 (see FIG. 2) is formed at the connecting portion between the unit cap 2 and the acoustic tube 3, and this air hole 25 connects the inner space of the unit cap 2 and the inner space of the acoustic tube 3.

[0012] As shown in FIG. 2, the unit cap 2 mainly includes a unit holding wall 21, a communication hole 22, a rear chamber wall 23, a notch 24, and an air hole 25.

[0013] The unit holding wall 21 is a cylindrical member formed inside the unit cap 2. The unit holding wall 21 holds the side wall of the driver unit 5. That is, the inner space of the unit holding wall 21 serves as a unit accommodating section 21a that accommodates the driver unit 5. Since the driver unit 5 is fitted into the unit accommodating section 21a with almost no gap, the central axis of the driver unit 5 is substantially aligned with the central axis 21x of the unit accommodating section 21a.

[0014] A diaphragm 6 is disposed on the front surface of the driver unit 5. The front of the diaphragm 6 is connected to the inner space of the acoustic tube 3 via an air vent 25. As a result, the inner space of the acoustic tube 3 becomes a front air chamber 3s.

[0015] A central axis 21x of the unit accommodating portion 21a defined by the unit holding wall 21 is eccentric from a central axis 2x of the unit cap 2. According to this configuration, compared to a configuration in which the driver unit 5 is disposed at the axial center of the unit cap 2, even if the unit cap 2 is small, a space 2s can be formed on the side of the driver unit 5.

[0016] 2 and 3, the unit cap 2 has a communication hole 22 formed in front of the unit holding wall 21. The communication hole 22 is a through hole that communicates between the front and rear surfaces of the unit cap 2. The communication hole 22 is formed in the front surface of the unit cap 2, in a wall surface that defines the space 2s. In other words, the communication hole 22 is formed on the opposite side of the unit cap 2 to the acoustic tube 3 in the radial direction.

[0017] The communication hole 22 is formed across the radially inner and outer sides of the unit holding wall 21. As a result, the inner and outer sides of the unit holding wall 21 are communicated with each other via the communication hole 22 and the front space outside the unit cap 2. Furthermore, at the upper and lower ends of the communication hole 22 in the y direction (see FIG. 3), a step 22a is formed by cutting out part of the thickness of the unit cap 2, and the step 22a may be formed into an appropriate shape to adjust the ventilation volume and the way the air escapes. The position of the communication hole 22 in the drawing is an example, and it goes without saying that it is not limited to a configuration in which it is disposed in a vertical section passing through approximately the center of the acoustic tube 3 as in Fig. 2. The communication hole 22 only needs to be formed across the radial inner and outer sides of the unit holding wall 21, and may be disposed above or below the position in Fig. 4 along the curved surface of the unit holding wall 21. In that case, the communication hole 22 is disposed to the left of the position in Fig. 4 according to the curvature of the unit holding wall 21.

[0018] As shown in Fig. 2 and Fig. 4, a rear chamber wall 23 is disposed in the space 2s. The rear chamber wall 23 is a partial cylindrical body disposed radially outward of the unit holding wall 21. The rear chamber wall 23 is U-shaped in a plan view (see Fig. 4). The space inside the rear chamber wall 23 communicates with the communication hole 22. As a result, the space surrounded by the rear chamber wall 23 and the unit holding wall 21 forms a rear air chamber 23s that communicates with the front air chamber 3s via the communication hole 22.

[0019] According to the above-mentioned configuration, the air pressure generated when the earphone 1 is attached to the ear canal escapes from the front air chamber 3s through the communication hole 22. Also, according to the above-mentioned configuration, air flows through the communication hole 22 in response to the pressure in the direction of pulling the diaphragm 6 generated when removing the earphone 1 and the pressure change generated when removing the earphone 1 from the package. Therefore, even in a small earphone with a small space between the diaphragm 6 and the eardrum, the change in air pressure on the front surface of the diaphragm 6 can be reduced. As a result, deformation and damage of the diaphragm 6 can be prevented. In addition to when the earphone 1 is attached, the change in air pressure during packaging and transportation can also be reduced.

[0020] Furthermore, with the configuration in which the communication hole 22 communicates with the space 2s, air can escape to the rear side, reducing the load on the diaphragm 6 and allowing the diaphragm 6 to vibrate accurately with good responsiveness. In other words, earphones with high sound quality can be realized.

[0021] Furthermore, according to the configuration in which the rear chamber wall 23 is provided in the space 2s to form the rear air chamber 23s, the inflow and outflow of air is controlled, so that low-frequency sound pressure can be guaranteed.

[0022] A housing 4 that covers the rear surface of the driver unit 5 is connected to the rear surface of the unit cap 2. An inner space 4s of the housing 4 is connected to the rear air chamber 23s. With this configuration, the vibration of the air in the rear air chamber 23s can be transmitted to the space 4s as well. In this embodiment, the housing 4 is provided with a communication hole (not shown) with the outside air, but the housing 4 may not be provided with the communication hole, and the inner space 4s of the housing 4 and the rear air chamber 23s may be connected to the outside air via only one communication hole 22. Moreover, the rear chamber wall 23 may not be provided. In this case, the space 4s and the space 2s inside the housing 4 communicate with the outside air via the communication hole 22.

[0023] 2, 4 and 5, the notch 24 is formed by cutting out the wall surface around the communication hole 22, i.e., a part of the unit holding wall 21 and the inner wall of the front surface of the unit cap 2, in the thickness direction. In this embodiment, the notch 24 is shaped such that the unit holding wall 21 and the unit cap 2 are cut out in a generally L-shape in vertical cross section. The notch 24 is shaped such that the unit holding wall 21 is cut out in a rectangular shape. Note that the detailed aspect is not limited to the above.

[0024] An acoustic resistor 7 is housed in the cutout 24. The acoustic resistor 7 is disposed in a substantially L-shape along the cutout 24. The acoustic resistor 7 covers at least a portion of the communication hole 22. More specifically, the acoustic resistor 7 is disposed in the communication hole 22 between the unit accommodating portion 21a and the front space of the unit cap 2. That is, the front air chamber 3s and the rear air chamber 23s are in communication with each other via the acoustic resistor 7.

[0025] The acoustic tube 3 is connected to a position eccentric to the central axis 21x side of the unit housing portion 21a with respect to the axial center of the unit cap 2. That is, the front air chamber 3s formed by the acoustic tube 3 is formed on the front side of the driver unit 5. Therefore, the vibration of the diaphragm 6 is transmitted from the front surface of the diaphragm 6 to the front air chamber 3s.

[0026] Here, the higher the frequency, the more linear the vibration tends to progress. In this regard, according to the present configuration in which the acoustic tube 3 is eccentric to match the position of the driver unit 5, the diaphragm 6 faces the front air chamber 3s through the air vent 25, so that the vibration of mid-to-high frequency sounds can be sufficiently transmitted to the opening of the acoustic tube 3. In other words, according to this configuration, even with a small earphone, a mid-to-high frequency sound source can be reproduced with high quality sound.

[0027] More specifically, the acoustic tube 3 may be disposed at a position where an imaginary straight line 3x along the central axis of the acoustic tube 3 passes through the center of the air vent 25. With this configuration, the air vent 25 is sufficiently open to the front air chamber 3s formed by the acoustic tube 3, and the vibration of the diaphragm 6 is transmitted linearly to the front air chamber 3s, so that even a small earphone 1 can reproduce high-quality sound from a mid-to-high frequency sound source.

[0028] 2, the central axis 21x of the unit accommodating portion 21a is drawn to be substantially parallel to the central axis 2x of the unit cap 2. That is, the central axis of the driver unit 5 is substantially parallel to the central axis 2x of the unit cap 2. However, the technical scope of the present invention is not limited to this, and the central axis 21x of the unit accommodating portion 21a may be formed to be inclined with respect to the central axis 2x of the unit cap 2. That is, the driver unit 5 may be accommodated to be inclined with respect to the central axis 2x of the unit cap 2.

[0029] Also, the acoustic tube 3 may be connected obliquely to the front surface of the unit cap 2, and the driver unit 5 may be housed at an angle to the axial direction of the acoustic tube 3. The central axis 21x of the unit housing portion 21a and the central axis of the driver unit 5 may be substantially parallel to the virtual straight line 3x along the central axis of the acoustic tube 3. In this case, the driver unit 5 and the diaphragm 6 face the vent hole 25 and the front air chamber 3s formed inside the acoustic tube 3. Even with this configuration, the vibration of the mid-high frequency sound generated by the diaphragm 6 can be sufficiently transmitted to the opening of the acoustic tube 3. Also, the size of the earphone 1 can be reduced. Furthermore, such a configuration can improve the degree of freedom in the design and structure of the earphone.

[0030] Furthermore, the configuration according to the present invention allows earphones to be made smaller while maintaining sound quality, making it possible to realize earphones with a thinner acoustic tube than conventional earphones. Therefore, the configuration according to the present invention allows the realization of earphones suitable for users with small ears or narrow ear canals.

[0031] Frequency response characteristics FIG. 6 shows the frequency characteristics of an earphone. That is, the horizontal axis shows frequency, and the vertical axis shows output level (dBV). The dashed line shows the frequency characteristics of an earphone according to the related art, and the solid line shows the frequency characteristics of the earphone 1 according to the present invention. FIG. 6 also shows the frequency characteristics of the earphone according to the related art superimposed. The earphone according to the related art has a structure in which the driver unit is accommodated in the approximate axial center of the unit cap, and does not have a configuration corresponding to the space 2s. Also, the acoustic tube of the earphone according to the related art is connected to the axial center of the unit cap.

[0032] As shown in Fig. 6, the earphone 1 maintains a higher sound pressure in the low frequency band F1 above 1 kHz than the earphone of the related art. That is, the earphone 1 can reproduce low-frequency sounds with high quality, despite the small external dimensions of the unit cap 2. Also, in the high frequency band F2, which is a band with a higher frequency than the low frequency band F1, the fluctuation range of the sound pressure is smaller compared to the earphone of the related art. That is, the earphone 1 can output a stable sound even in the high frequency band.

[0033] According to the embodiment described above, it is possible to provide earphones that reduce pressure on the diaphragm and produce high quality sound. Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0034] 1. Earphones 2 Unit Cap 21 Unit Retaining Wall 21a Unit storage section 21x Central axis of unit housing 22 Communication hole 23 Rear chamber wall 23s Rear air chamber 3 sound tube 3s Front air chamber 4. Housing 5 Driver Unit 6 diaphragm

Claims

1. A diaphragm; A driver unit having the diaphragm on a front surface thereof; a unit cap that houses the driver unit; an acoustic tube connected to a front surface of the unit cap and forming a front air chamber in front of the diaphragm; Equipped with The unit cap is a unit holding wall that holds a side wall of the driver unit; a communication hole in front of the unit holding wall, the communication hole connecting the inside and outside of the unit holding wall and the front and rear surfaces of the unit cap; Equipped with Earphones.

2. The acoustic tube is connected to a position eccentric to a central axis of the unit holding wall with respect to the axial center of the unit cap. The earphone according to claim 1.

3. The acoustic tube is connected obliquely to the front surface of the unit cap, The driver unit is housed at an angle to the axial direction of the acoustic tube and faces the front air chamber formed inside the acoustic tube. The earphone according to claim 1.

4. An air hole is formed at a connecting portion between the unit cap and the acoustic tube, the air hole communicating the diaphragm and the front air chamber, and a virtual straight line along a central axis of the acoustic tube passes through a center of the air hole. The earphone according to any one of claims 1 to 3.

5. The communication hole is formed on the opposite side of the unit cap to the acoustic tube in the radial direction. The earphone according to claim 1.

6. the unit cap further includes a rear chamber wall that is disposed on a rear surface side of the unit cap and radially outward of the unit holding wall and that forms a rear air chamber that communicates with the communication hole; The earphone according to claim 1.

7. A housing that covers the rear surface of the driver unit is connected to the rear surface of the unit cap, and an inner space of the housing communicates with the rear air chamber. The earphone according to claim 6.

8. At least one of a front end portion of the unit holding wall and an inner wall on a front surface of the unit cap has a notch formed by cutting the unit holding wall or the inner wall in a thickness direction, An acoustic resistor is housed in the cutout, The front air chamber and the rear air chamber are in communication with each other via the acoustic resistance material. The earphone according to claim 6.

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