JP5367989B2 - Inner ear headphones - Google Patents

Abstract

The aim of the invention is to provide a headphone for adopting the headphone unit for braking the low-frequency resonance with a simple structure, wherein, an earphone (100) comprises the following components: a sound generating part side cover (110), fine holes (111), a back side cover (120) and an electroacoustic switching component (200). The electroacoustic switching component (200) is provided with a vibrating plate (201) which switches audio signal to sound and sends out sound wave. The electroacoustic switching component (200) is closed by the sound generating side cover (110) and the back side cover (120). The fine holes (111) which has an aperture opening ratio with a specific proportion relatively to the area of vibrating plate (201) are installed on the sound generating part side cover (110) for restraining the resonance of vibrating plate (201).

Description

The present invention relates to an inner-ear headphone that converts an electrical signal output from a playback device or a receiver into an audible sound wave using a speaker that is brought close to the ear , and more particularly, braking for suppressing resonance of a diaphragm. The present invention relates to a damperless inner-ear headphone having no members.

  Conventionally, an earphone as a headphone is connected to an audio output device such as a television, radio, personal computer, audio player, etc., and a speaker provided in the earphone is attached to the auricle without causing surrounding people to listen to the sound. In general, listening to the sound output from the sound output device is performed.

  Since such an earphone requires a small and flat transducer, it cannot be provided with a braking member (damper) for suppressing resonance of the diaphragm, unlike a general speaker. It is difficult to provide a magnetic circuit, and sufficient electromagnetic braking due to the output impedance of the amplifier cannot be obtained. As a result, there has been a problem that an enhanced sound due to the low-frequency resonance f0 occurs at a frequency of about 200 Hz.

  Here, the low-frequency resonance f0 generated in the conventional earphone will be described with reference to FIG. FIG. 6 is a graph showing frequency characteristics of a conventional earphone. A graph 600 shown in FIG. 6 is a measurement result of pink noise. In FIG. 6, the vertical axis represents sound pressure (dB) and the horizontal axis represents frequency (Hz). As shown in the waveform of the graph 600, the sound pressure is high in a low frequency range of about 200 Hz, that is, the diaphragm is strongly resonating at the frequency. The resonance that occurs in this low frequency range is the low frequency resonance f0. In addition, if it supplements about calculation of f0, it calculates with the following (1) Formula.

f0 = (S / M) ^1/2 / 2π (1) formula

  S is a stiffness constant, and M is the mass of a vibration system including a diaphragm and a voice coil. In order to suppress the low-frequency resonance f0 expressed by the equation (1), it is desirable to provide a mechanical resistance by applying a viscous material to the diaphragm itself corresponding to the stiffness. Decrease or deterioration of acoustic characteristics will occur.

  In addition, as a conventional technique that can adjust the frequency characteristics, for example, there is a technique that has functions of a speaker and an earphone and adjusts the frequency characteristics so that the frequency characteristics are suitable for the earphone when used as an earphone. It has been proposed (for example, see Patent Document 1 below).

JP 2005-318267 A

  However, even if the frequency characteristic is adjusted by using the technique of Patent Document 1 described above and the increase of the natural frequency at the low-frequency resonance f0 is suppressed, it is not possible to cope with the variation in f0 of the earphones and the temperature change of f0. Further, the technique disclosed in Patent Document 1 requires control by the control unit, and there is a problem in that the low-frequency resonance f0 cannot be braked as a single earphone.

In order to solve the above-described problems caused by the prior art, the present invention is an inner-ear type headphone that can perform low-frequency resonance f0 braking with a single headphone while having a simple configuration without requiring control by a control unit or the like. The purpose is to provide.

In order to solve the above-described problems and achieve the object, an inner-ear type headphone according to the present invention is an inner-ear type headphone worn on an auricle, and includes a diaphragm included in an electroacoustic transducer that converts an audio signal into sound. The electroacoustic transducer is hermetically sealed, and is provided in an apparatus housing composed of a housing on the sound generating unit side and a housing on the back side, and a housing on the sound generating unit side to suppress resonance of the diaphragm. And an air hole having an aperture ratio of 0.5 to 3% with respect to the area of the diaphragm and outputting sound.

  According to the present invention, since the electroacoustic transducer is accommodated in the sealed device casing provided with only the minute holes, a certain sound can be output from the minute holes, while the air in the device casing is minute. Sufficient mechanical resistance can be given to the diaphragm with mechanical resistance flowing in and out of the hole. Thereby, low-pass resonance can be suppressed.

According to the inner-ear headphone of the present invention, it is possible to perform low-frequency resonance braking with a single headphone while having a simple configuration, and it is possible to improve sound quality and reduce user fatigue. Play.

Exemplary embodiments of an inner-ear headphone according to the present invention will be explained below in detail with reference to the accompanying drawings. In the following description, an example in which the inner ear headphones of the present invention are implemented using an earphone attached to the auricle will be described.

(Embodiment)
(Earphone configuration)
The configuration of the earphone according to the embodiment of the present invention will be described. FIG. 1 is a configuration diagram of an earphone 100 according to an embodiment of the present invention. In FIG. 1, the earphone 100 includes, as a device housing 101, a sounding unit side case 110 that is a sounding unit side housing, a back side case 120 that is a back side housing, and a tube unit 130. .

  The sound generating unit side case 110 has a fine hole 111 on the surface to be attached to the auricle. The fine holes 111 are a plurality of circular air holes, and output sound by vibration of a diaphragm described later. The back side case 120 is fitted to the sound generation unit side case 110 without a gap. The cylindrical portion 130 is formed integrally with the back side case 120 and incorporates a cord 131. The cord 131 is connected to an audio output device such as a portable audio player or a portable radio.

(Internal configuration of earphone)
Next, the internal configuration of the earphone 100 according to the present embodiment will be described with reference to FIG. FIG. 2 is an exploded perspective view showing the internal configuration of the earphone 100 according to the present embodiment.

  In FIG. 2, the earphone 100 includes an electroacoustic transducer 200 inside a sound generation unit side case 110 and a back side case 120. The electroacoustic transducer 200 is in contact with the outside air only through the minute holes 111 because the sound generating unit side case 110 and the back side case 120 are fitted with no gap. The electroacoustic transducer 200 includes a diaphragm 201, a voice coil 202, and a connection line 203.

  The diaphragm 201 is driven by the voice coil 202 to vibrate and emit sound waves in the air. The voice coil 202 vibrates the diaphragm 201 in the magnetic circuit of the electroacoustic transducer 200 by giving an electric signal. The connection line 203 is built in the cord 131 and transmits an electrical signal.

  Here, the fine hole 111 provided in the sound generating unit side case 110 will be described in detail. The fine hole 111 is provided at one position in the center of the sound generating unit side case 110 and outputs sound waves radiated from the diaphragm 201. The fine hole 111 has an opening ratio of a predetermined ratio with respect to the area of the diaphragm 201. The predetermined aperture ratio is preferably in the range of about 0.5 to 3%, and most preferably about 1%, with respect to the area of the diaphragm 201. In this embodiment, the aperture ratio is 1.147%.

  Further, in the present embodiment, the fine holes 111 are provided at one place as a circular shape, but the number and shape thereof are arbitrary as long as the aperture ratio has a predetermined ratio with respect to the area of the diaphragm 201. Can be selected. When a plurality of fine lights 111 are provided, it is necessary to add a plurality of holes to obtain a predetermined ratio of aperture ratio.

  Furthermore, the fine holes 111 can be provided not only in the sound generating unit side case 110 but also in the back side case 120. Also in this case, it is possible to provide a plurality of fine holes 111. In this case, the entire fine hole 111 provided in the sound generating unit side case 110 and the fine hole 111 provided in the back side case 120 have an aperture ratio of a predetermined ratio with respect to the area of the diaphragm 201. Cost.

(Frequency characteristics of the earphone according to the present embodiment)
Next, the frequency characteristics of the earphone 100 according to the present embodiment will be described with reference to FIG. FIG. 3 is a graph showing frequency characteristics of the earphone 100 according to the present embodiment. A graph 300 shown in FIG. 3 is a measurement result of pink noise. In FIG. 3, the vertical axis indicates the sound pressure, and the horizontal axis indicates the frequency.

  Here, it supplements about the structure of the conventional earphone which becomes the frequency characteristic shown in FIG. In the conventional earphone, the aperture ratio of the air hole for sound generation is at least about 5%, and the aperture ratio of the earphone showing the measurement result of FIG. 6 is 4.590%.

  The graph 300 shown in FIG. 3 has a lower sound pressure in a low frequency range of about 200 Hz indicated by reference numeral 301 than the graph 600 using the conventional earphone shown in FIG. This indicates that when the vibration plate 201 vibrates, sound waves are emitted only from the fine holes 111 and vibration of the vibration plate 201 is suppressed at the frequency. This is because the low-frequency resonance is suppressed by the mechanical resistance of the air that the diaphragm 201 flows in and out of the fine holes 111.

  On the other hand, in the conventional earphone shown in FIG. 6, when the vibration plate 201 vibrates, the sound generation air hole is large with respect to the vibration plate 201, so that mechanical resistance of inflowing and inflowing air hardly occurs and vibration is generated. A sufficient mechanical resistance is not applied to the plate 201. As a result, low-frequency resonance occurs in the conventional earphone.

  As described above, earphone 100 according to the present embodiment can suppress low-frequency resonance of diaphragm 201.

(Relationship between micropore opening ratio and level difference)
As a result of intensive studies, the present inventor has found that it is effective that the aperture ratio of the fine holes 111 is 0.5 to 3%. Regarding this, first, the relationship between the aperture ratio of the fine holes 111 and the level difference will be described with reference to FIG. FIG. 4 is a graph showing the relationship between the aperture ratio of the fine holes 111 and the level difference. As an overview of FIG. 4, the graph 400 shows that the lower the resonance, the lower the level difference shown on the vertical axis.

  In FIG. 4, the vertical axis represents the level difference (dB) between 200 Hz and 1 kHz, and the horizontal axis represents the aperture ratio of the fine holes 111. First, each plot point will be described. A plot point 401 indicates a level difference between 200 Hz and 1 kHz in the earphone 100 (aperture ratio = 1.147%) used in the present embodiment. That is, the difference between the 200 Hz level indicated by reference numeral 301 in FIG. 3 and the 1 kHz level indicated by reference numeral 302 is shown.

  On the other hand, a plot point 402 indicates a level difference between 200 Hz and 1 kHz in a conventional earphone (aperture ratio = 4.590%). That is, the difference between the 200 Hz level indicated by f0 in FIG. 6 and the 1 kHz level indicated by reference numeral 601 is shown. Similarly, for the other plot points shown in FIG. 4, that is, for the earphones with other aperture ratios corresponding to the plot points, the frequency characteristics are measured, and the result of calculating the level difference between 200 Hz and 1 kHz is obtained. Show.

  For example, when the plot point 401 and the plot point 402 are compared, the level difference is smaller in the plot point 401 than in the plot point 402. That is, the plot point 401 indicates that the level difference between the frequencies of 200 Hz and 1 kHz is small, and low-frequency resonance is unlikely to occur. As shown in the graph 400, it can be seen that the lower the resonance, the lower the resonance is, and the higher the aperture, the easier the low-frequency resonance occurs.

  Further, as shown in the graph 400, when the aperture ratio is about 3% or less, the level difference is significantly reduced as compared with the case where the aperture ratio exceeds about 3%. That is, if the aperture ratio is about 3% or less, the frequency characteristic graph (see FIGS. 3 and 6) can be flattened (reduced to around 200 Hz), and low-frequency resonance can be suppressed.

(Relationship between aperture ratio of micropores and sensitivity)
Next, the relationship between the aperture ratio of the fine holes 111 and the sensitivity will be described with reference to FIG. FIG. 5 is a graph showing the relationship between the aperture ratio of the fine holes 111 and the sensitivity. As an overview of FIG. 5, the graph 500 indicates that the higher the sensitivity shown on the vertical axis, the better the state of voice transmission.

  In FIG. 5, the vertical axis indicates the sensitivity, and the horizontal axis indicates the aperture ratio of the fine hole 111. First, each plot point will be described. A plot point 501 indicates the sensitivity of the earphone 100 (aperture ratio = 1.147%) used in the present embodiment. On the other hand, the plot point 502 indicates the sensitivity of the conventional earphone (aperture ratio = 4.590%).

  For example, when the plot point 501 and the plot point 502 are compared, the sensitivity does not change greatly between the plot point 501 and the plot point 502. As shown in the graph 500, it can be seen that when the aperture ratio is about 1% or more, the sensitivity is a substantially constant value. On the other hand, if the aperture ratio is less than about 1%, the sensitivity decreases. In particular, when the aperture ratio is less than about 0.5% (plot point 503), the user listens and feels uncomfortable. Therefore, if the aperture ratio is about 0.5% or more, a constant sensitivity can be maintained.

  Thus, in order to maintain a constant sensitivity, it is sufficient that the aperture ratio is about 0.5% or more as shown in FIG. 5, and in order to reduce low-frequency resonance, it is shown in FIG. As just described, the aperture ratio may be about 3% or less. Therefore, it is desirable that the aperture ratio of the fine holes 111 is about 0.5 to 3%. In particular, if the aperture ratio is about 1%, low-frequency resonance can be effectively reduced while maintaining good sensitivity.

  In the present embodiment, the headphone of the present invention is realized by the earphone 100 worn on the auricle, but the present invention is not limited to the earphone 100 shown in the present embodiment, and the vibration of the diaphragm is The present invention can be applied to a damperless headphone that does not have an attenuation member for attenuation. In addition, the earphone 100 is not limited to the type that is attached to the auricle, but the type that is inserted into the ear canal, the type that the headband is placed on the head, the type that the clip is hooked on the outer ear, etc. Can do.

  As described above, according to the earphone 100 according to the present embodiment, the electroacoustic transducer 200 is disposed in the sealed device casing 101 and the microscopic holes 111 are provided to brake the diaphragm 201. When the vibration plate 201 vibrates, sound waves are emitted only from the fine holes 111 and sufficient mechanical resistance can be given to the vibration plate 201. Thereby, low frequency resonance can be suppressed and sound quality can be improved. Therefore, it is possible to reduce the feeling of fatigue that the user feels when listening to sound for a long time.

  Further, in the earphone 100 according to the present embodiment, the fine hole 111 can be provided in the sound generating unit side case 110 and the back side case 120. Even with such a configuration, low-frequency resonance can be suppressed, and the sound quality can be adjusted by, for example, improving the sound quality of high sound by the fine holes 111 provided in the back side case 120.

  Further, in the earphone 100 according to the present embodiment, the aperture ratio of the fine holes 111 is set to a range of about 0.5 to 3% with respect to the area of the diaphragm 201, so that low-frequency resonance can be effectively suppressed. Can do. In the present embodiment, since the aperture ratio of the fine holes 111 is about 1% with respect to the area of the diaphragm 201, low-frequency resonance can be suppressed most effectively.

  As described above, according to the headphone according to the present invention, it is possible to perform low-frequency resonance braking with the headphone alone, while improving the sound quality and reducing the fatigue of the user, with a simple configuration. Can do.

The headphone according to the present invention relates to an inner-ear type headphone that converts an electric signal output from a playback device or a receiver into an audible sound wave using a speaker that is brought close to the ear , and in particular, vibration of a diaphragm such as an earphone. It is suitable for a damperless inner-ear type headphone that does not have a damping member for attenuating sound.

1 is a configuration diagram of an earphone according to an embodiment of the present invention. It is the disassembled perspective view which showed the internal structure of the earphone concerning this Embodiment. It is the graph which showed the frequency characteristic of the earphone concerning this Embodiment. It is the graph which showed the relationship between the opening rate of a micropore, and a level difference. It is the graph which showed the relationship between the aperture ratio of a micropore, and a sensitivity. It is the graph which showed the frequency characteristic of the conventional earphone.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Earphone 101 Apparatus housing 110 Sound generation part side case 111 Micro hole 120 Back side case 200 Electroacoustic transducer 201 Diaphragm 202 Voice coil

Claims (1)

In the earbud headphones worn on the auricle,
A diaphragm included in an electroacoustic transducer that converts an audio signal into sound;
The electroacoustic transducer is hermetically sealed, and a device housing composed of a housing on the sound generating unit side and a housing on the back side,
An air hole provided in a housing on the sounding unit side to suppress resonance of the diaphragm, having an aperture ratio of 0.5 to 3% with respect to the area of the diaphragm, and outputting sound;
Inner ear headphones characterized by having

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