JP5297957B2 - headphone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent pressure inside a forward cavity from rapidly changing when mounting headphones. <P>SOLUTION: The headphone 1 includes: an electroacoustic transducer 10 attached onto nearly the center of a baffle plate 20; a headphone casing 30 for forming a rear cavity RC of prescribed volume on the back of the baffle plate 20; and an ear pad 40 that is attached over the entire periphery on the front of the baffle plate 20 and forms a front cavity FC between a temple HS of a human body and the baffle plate 20. The ear pad 40 comprises an elastic body 41 that is covered with a non-permeable outer cover 42 and includes continuous bubbles. In this case, an air flowing port 43 having prescribed thin air layer resistance R is provided on an outer side 40c of a free space in the ear pad 40. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a headphone, and more particularly to a headphone provided with an ear pad that can prevent a sudden pressure change in a front cavity.

  Headphones that are worn on the temporal region of the human body so as to cover the ears are provided with an ear pad having an elastic body on the ear pad side.

  When the ear pad is applied to the side of the human body, it forms an airtight space (front cavity) on the sound emitting surface side of the headphones. In particular, a headphone having a noise canceling function is designed so that the airtightness of the front cavity is higher in order to improve sound insulation in a low sound range.

  When the headphones are attached to the head of the human body, the ear pad is pressed against the side of the head by the side pressure applied by the headband, so that the volume of the ear pad is reduced and the ear pad is in close contact with the side of the head by the repulsive force of the internal elastic body.

  At this time, if the volume of the ear pad is rapidly decreased, the pressure fluctuation per unit time in the front cavity increases, which may cause discomfort to the user.

  One way to relieve such sudden pressure fluctuations is to stiffen the elasticity of the elastic body so that the volume of the earpad does not decrease rapidly. This is not preferable.

  Therefore, in the invention described in Patent Document 1, in a headphone having a noise canceling function, a pad material obtained by coating an ear pad with an elastic body having open cells such as a sponge material with a non-breathable outer skin made of synthetic leather or the like. And an air circulation hole is provided in the outer skin so that the atmospheric pressure fluctuation in the front cavity is moderated when the headphones are attached and detached.

JP 2001-69590 A

  However, in the headphones described in Patent Document 1, the following problems have been pointed out because the air circulation holes are arranged on the inner side surface of the ear pad (the surface side forming the front cavity). .

  That is, when the headphones are worn, the ear pad is compressed by the side pressure applied by the headband, so that the compressed air in the ear pad enters the front cavity, and the pressure in the front cavity is increased.

  When this pressure change is picked up by the microphone unit arranged in the front cavity, a signal that cancels the pressure change is output from the noise cancellation active circuit to the headphone unit (electroacoustic transducer), which is noise. May be heard.

  In a headphone having a noise canceling function, a small electret condenser microphone unit that does not particularly require a polarization voltage is usually used as the microphone unit.

  As described above, when the pressure in the front cavity is increased, the distance between the diaphragm of the electret condenser microphone unit and the fixed pole is offset according to the pressure, so the noise cancellation sensitivity changes. May end up.

  As a result, the stability of the noise canceling active circuit is impaired, and the noise canceling active circuit is a feedback type, and in some cases, self-oscillation may occur.

  Although this self-oscillation depends on the situation, it stops when the pressure rise (or pressure drop) in the front cavity due to the pressing force (or pulling force) on the ear pad is alleviated.

  However, although it is a short time, it is not preferable for the user to listen to a large oscillation sound while wearing the headphones.

  Therefore, an object of the present invention is to provide a headphone in which the pressure in the front cavity does not change abruptly when the headphone is worn.

  In order to solve the above-described problems, the present invention provides an electroacoustic transducer mounted substantially at the center of a baffle plate, a headphone housing that forms a rear cavity of a predetermined volume on the back side of the baffle plate, and the baffle plate. A front pad that is attached over the entire periphery of the front side of the body and includes an ear pad that forms a front cavity between the human head and the baffle plate, and the ear pad is covered with a non-breathable outer skin. A headphone made of an elastic body having bubbles is characterized in that an air circulation port having a predetermined thin air layer resistance is provided on the outer surface of the ear pad on the free space side.

  In this invention, it is preferable that the said air circulation port consists of a pair of guide board arrange | positioned on both sides of the predetermined space | gap used as the said thin air layer resistance.

  Further, the present invention is preferably a headphone having a noise canceling function in which a noise canceling microphone unit is housed in the front cavity.

  According to the present invention, an electroacoustic transducer mounted almost at the center of the baffle plate, a headphone housing that forms a rear cavity of a predetermined volume on the back side of the baffle plate, and the entire peripheral portion on the front side of the baffle plate. A headphone comprising an elastic body that is attached over the circumference and includes an ear pad that forms a front cavity between a human head and the baffle plate, and the ear pad is covered with a non-breathable outer skin. In the ear pad free space side outer surface provided with an air circulation port having a predetermined thin air layer resistance, the deformation due to the side pressure of the ear pad when wearing the headphones becomes gentle, Abrupt changes in pressure in the front cavities as air is released into free space and does not enter the front cavities It is possible to prevent.

  Therefore, especially in headphones with a noise cancellation function in which a microphone unit for noise cancellation is housed in the front cavity, the sensitivity of the microphone unit can be maintained well and the noise cancellation active circuit operates stably. Can be made.

1 is a schematic cross-sectional view showing a headphone according to an embodiment of the present invention. (A) The disassembled perspective view which shows the structure of the air circulation port provided in the ear pad of the said headphones, (b) The AA sectional view taken on the line. (A) The equivalent circuit schematic of the said air circulation port, (b) The graph which shows the pressure decay curve of a front cavity.

  Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 3, but the present invention is not limited to this.

  As shown in FIG. 1, a headphone 1 according to this embodiment includes, as a basic configuration, a speaker unit 10 as an electroacoustic transducer, a baffle plate 20 that supports the speaker unit 10 at a central portion, and a baffle plate 20. A headphone housing 30 that forms a rear cavity RC of a predetermined volume on the back surface side, and an ear pad 40 that forms a front cavity FC between the human body head HS and the baffle plate 20.

  In this embodiment, a dynamic speaker unit including a diaphragm 11 having a voice coil 12 and a magnetic circuit 13 having a permanent magnet 14 and providing a magnetic gap to the voice coil 12 is used for the speaker unit 10. However, in some cases, an electrostatic speaker unit may be used.

  The headphone case 30 is formed in a bowl shape from a synthetic resin material or wood, and the pair of headphones 1 is a headband (both not shown) via a universal joint-shaped hanger at the headphone case 30 portion. Supported at both ends.

  The ear pad 40 is attached over the entire periphery of the peripheral portion on the front surface side of the baffle plate 20, and includes a top surface 40 a that abuts the temporal head HS around the ear E of the human body, An inner side surface 40b that forms the front cavity FC therebetween and an outer side surface 40c facing the free space are provided. The front side of the baffle plate 20 is the sound emitting surface side of the speaker unit 10.

  The ear pad 40 includes an elastic body 41 having open cells, such as sponge, as a core material. The ear pad 40 is entirely covered with an outer skin 42 such as synthetic leather that has almost no air permeability.

  The headphone 1 according to this embodiment includes a microphone unit 50 for noise cancellation in the front cavity FC. In connection with the microphone unit 50, the headphone 1 is equipped with a feedback active noise canceling circuit (not shown). The microphone unit 50 is preferably an electret condenser microphone unit that is small and does not require a polarization power source.

  Since the ear pad 40 has a top surface portion 40a that is in close contact with the temporal region HS and the outer skin 42 is non-breathable, the front cavity FC is highly airtight.

  Therefore, when the headphones are worn, the pressure in the front cavity FC increases rapidly due to the side pressure applied by the headband. This not only makes the user uncomfortable, but also causes the operation of the feedback active noise cancellation circuit to become unstable.

  Therefore, in the present invention, an air circulation port 43 having a predetermined thin air layer resistance R is provided on the outer surface 40 c side of the ear pad 40.

  As shown in FIGS. 2A and 2B, in this embodiment, in order to form the air circulation port 43, the first guide plate 431 attached along the baffle plate 20 and a predetermined interval are provided. And a second guide plate 432 attached to the first guide plate 431 via a pair of left and right double-sided adhesive (or adhesive) tapes 433 and 433, and air flow through a slit-shaped opening between them. A mouth 43 is formed.

  As an example, a PET film having a thickness of 0.5 mm can be used for the first and second guide plates 431 and 432, and the thickness of the double-sided adhesive tapes 433 and 433 is 0.3 mm. When the distance between the double-sided adhesive tapes 433 and 433 is L, an air circulation port 43 having a thin air layer resistance of L × 0.3 mm is obtained.

  According to this, when the headphones are mounted, the ear pad 40 is pressed against the temporal head HS by the side pressure applied by the headband and the elastic body 41 is compressed, but the air in the ear pad 40 has an air resistance R. Since it is gradually released into the free space through the circulation port 43, the ear pad 40 is gently deformed, and the pressure in the front cavity FC is gradually reduced accordingly.

  Therefore, the user's unpleasant feeling when wearing the headphones is reduced, and in the headphones having a noise canceling function, the feedback active noise canceling circuit can be operated stably.

  For reference, the graph of FIG. 3A shows the time-pressure relationship in the front cavity FC when headphones are attached. FIG. 3B shows an equivalent circuit diagram of the air circulation port 43.

  In this equivalent circuit diagram, I is a current source generated when the ear pad 40 is compressed, s is a stiffness obtained by combining the stiffness of the elastic body 41 with the stiffness of the elastic body 41 itself, and R is a thin air layer resistance.

  When removing the headphones 1, the atmosphere is gradually sucked into the ear pad 40 through the air circulation port 43 having the thin air layer resistance R as the headphones 1 are moved away from the temporal region HS. Therefore, the pressure in the front cavity FC does not change abruptly.

  As described above, the present invention has been described in the above embodiment, but the air circulation port 43 extends over the entire circumference of the outer side surface 40c of the ear pad 40 on the condition that the air in the ear pad 40 does not leak into the front cavity FC. It may be provided or may be provided partially.

  Moreover, the material of the guide plates 431 and 432 may be arbitrarily selected. Similarly, the spacer that holds the gap between the guide plates 431 and 432 is not limited to the double-sided adhesive tape 433. The desired thin air layer resistance R can be obtained depending on the arrangement interval and thickness of the spacers.

1 Headphone 10 Speaker unit (electroacoustic transducer)
20 Baffle plate 30 Headphone housing 40 Ear pad 40a Top surface portion 40b Inner side surface 40c Outer side surface 41 Elastic body 42 Outer skin 43 Air flow port 431, 432 Guide plate 433 Double-sided adhesive tape (spacer)
50 Microphone unit FC Front cavity RC Rear cavity

Claims (3)

An electroacoustic transducer mounted almost at the center of the baffle plate, a headphone housing that forms a rear cavity of a predetermined volume on the back side of the baffle plate, and a peripheral edge of the front side of the baffle plate. In a headphone comprising an elastic body having an open cell, comprising an ear pad that forms a front cavity between the human body side head and the baffle plate, and the ear pad is covered with a non-breathable outer skin.
A headphone characterized in that an air circulation port having a predetermined thin air layer resistance is provided on the outer surface of the ear pad on the free space side.   The headphone according to claim 1, wherein the air circulation port includes a pair of guide plates arranged to face each other with a predetermined gap serving as the thin air layer resistance.   The headphone according to claim 1 or 2, wherein a microphone unit for noise cancellation is housed in the front cavity.

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