JP2008154038A - Receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To flatten the frequency versus sound output characteristic of a receiver over a wide frequency region. <P>SOLUTION: In the receiver in which sound waves from a speaker propagate in a front air chamber space and is outputted from sound holes provided on a wall of an ear piece to the outside, a central portion occupying at least 1/4 area of an inner surface of the wall of the ear piece is blocked, and the sound holes are positioned in an area between the area of the central part and a circumferential wall of the front air chamber space. Since the sound waves emitted by the speaker accordingly propagate in the front air chamber space toward inner openings of the sound holes provided at the circumferential wall side of the wall of the ear piece, the sound waves come into mutual contact with one another only in a very narrow area near the center of a diaphragm to be able to reduce disturbance of airflow of the sound waves in the front air chamber space (attenuation of the sound waves in a high frequency region can be reduced) so that the frequency versus sound output characteristic of the receiver can be flattened over a wide frequency region. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a handset used in, for example, a telephone handset.

The conventional analog telephone line has an upper limit of the transmission frequency band of 3 to 3.4 kHz, but the ISDN digital line has a wider bandwidth up to an upper limit of the transmission frequency band of about 7 kHz. Furthermore, it is possible to use a voice transmission band up to 20 kHz on the IP line. If communication is performed over such a broadband line, the call quality is improved and voice etc. can be transmitted with high quality (clear), but in order for humans to feel the high quality voice signal transmitted, Furthermore, it is necessary to realize a wide band of the handset. Therefore, for example, as shown in FIG. 5, a front air chamber 30 is provided on the front side of an electroacoustic transducer (for example, a speaker, hereinafter sometimes simply referred to as “speaker”) 20, and the reception of the front air chamber 30 By propagating to the outside of the handset through the sound hole provided in the mouth, the frequency-to-sound output characteristic of the handset 10 is improved, and the rear chamber 40 is provided behind the speaker 20, so that the frequency-to-sound output characteristic of the handset 10 is provided. Has been developed (for example, Patent Documents 1 and 2). Here, the upper limit frequency of the sound output of the handset determined by the shape of the front air chamber (the upper limit frequency (hereinafter referred to as “fr”) that can be output without significant decrease in the sound output with respect to the electric signal input of the handset may be displayed. ) Is proportional to the square root of the number n of the sound holes in the front air chamber and inversely proportional to the square root of the sum of the volume c1 of the front air chamber and the equivalent volume c2 of the diaphragm of the speaker, as shown in equation (1). It is known to do.
fr = kr (n / c1 + c2) ^1/2 (1) Therefore, if the number of sound holes is increased by providing as many sound holes as can be arranged in the earpiece, the volume of the front air chamber 30 is also increased. If the volume of c1 is reduced, the handset 10 can be widened.
JP-A-10-150698 JP 2003-23482 A

  However, even if the volume c1 of the front air chamber is reduced, there is an equivalent volume c2 of the diaphragm of the speaker, so that there is a limit to the reduction of c1 + c2, and there is a limit to widening the band. Therefore, if the number n of sound holes is increased over the entire area of the earpiece to widen the band, the propagation path of sound waves from the diaphragm of the speaker to each sound hole is propagated to the adjacent sound holes (in FIG. 5). A region R (a region indicated by a dashed ellipse in FIG. 5) is generated. In these regions R, since the air current is disturbed by the collision of each sound wave due to the difference in propagation distance from the diaphragm to the adjacent sound hole, the sound wave in the high sound (high frequency) region is attenuated. As a result, the sound output characteristic in the high frequency region of the receiver is degraded (the quality of the reproduced sound of the receiver is degraded). Therefore, the present invention aims to realize a receiver capable of reducing the attenuation of high-frequency sound waves and flattening the frequency-to-sound output characteristics over a wide frequency range by preventing the disturbance of the airflow in the front air chamber. And

  In order to solve the above-described problem, a receiver according to the present invention has an electroacoustic transducer and a front air chamber as described in claim 1, and the front air chamber has an electroacoustic transducer on one end side. The front air chamber space which has the earpiece wall portion on the other end side and the front air chamber has is defined by the sound source side wall portion, the earpiece wall portion and the peripheral wall, and the sound waves generated by the electroacoustic transducer are In a receiver that propagates through the space and is output from the sound hole provided in the earpiece wall to the outside of the receiver, any inner opening of the plurality of sound holes defines the outer shape of the inner surface of the earpiece wall. Between the first closed curve and a second closed curve that is similar to the first closed curve and has a center of gravity at the same position and has a length that is one-half the length of the first closed curve. .

  Since such a second closed curve occludes a central portion occupying at least a quarter of the inner surface of the earpiece wall, the receiver is positioned in the region between the central portion and the first closed curve. Sound waves are output to the outside through the internal opening. The three-quarters of the inner surface of the earpiece wall is generated by the three-quarter sound waves generated from the outer periphery that occupies three-fourths of the diaphragm of the electroacoustic transducer, relative to the outside of the second closed curve. Is emitted from the outer peripheral portion that occupies and is not concentrated on the central portion that occupies one-fourth the area of the inner surface of the earpiece wall portion. Therefore, in the receiver, the sound waves traveling from the diaphragm of the electroacoustic transducer to each internal opening are in contact with each other in a very narrow region near the center of the diaphragm, and the turbulence of the airflow between the sound waves is small. (Attenuation of sound waves in the high frequency region can be reduced). Therefore, the receiver can flatten the frequency characteristics from the middle frequency to the vicinity of the high frequency region (for example, 10 kHz).

  The receiver according to claim 2 further has a curved surface complementary to the curved surface of the diaphragm of the electroacoustic transducer on the inner surface of the wall of the earpiece (for example, the diaphragm of the electroacoustic transducer is a convex curved surface). In some cases, a concave curved surface complementary to the convex curved surface is formed on the inner surface of the earpiece wall part), and a sound wave propagation path is formed between both curved surfaces, and the inner opening is formed on the inner curved surface of the earpiece wall part. It is located outside the third closed curve that defines the outer shape. Accordingly, the sound wave generated by the diaphragm of the electroacoustic transducer propagates through the propagation path between the complementary curved surfaces toward the internal opening of each sound hole, and is output to the outside from each sound hole. Therefore, in the receiver, the propagation of the sound wave is adjusted and the propagation path (the front air chamber) is more stable than the case where the curved surface complementary to the curved surface of the diaphragm of the electroacoustic transducer is not formed on the inner surface of the receiver wall. The turbulence of the airflow in the space can be further reduced. Thus, the handset can further improve the frequency characteristics from the mid-frequency to the vicinity of fr.

  In the receiver according to claim 3, the first closed curve is a circle, and a plurality of sound holes are provided on a sound hole array circle that is concentric with the first closed curve, so that the diaphragm to the inner opening of each sound hole. The propagation of the sound wave can be most optimally adjusted by making the objectivity / identity of each of the propagation paths to the best state (with the same propagation distance from the diaphragm to each sound hole). Therefore, the receiver can minimize the turbulence of the airflow in the front air chamber space, and further improve the frequency characteristics from the mid-range frequency to the vicinity of fr.

  As described above, the handset according to the present invention reduces the collision of sound waves propagating in the front air chamber space, thereby preventing turbulence of the air current in the front air chamber space, and generating high frequency sound waves in the front air chamber. The effect of reducing the attenuation and flattening the frequency-to-sound output characteristics over a wide frequency range can be obtained.

  Hereinafter, a receiver according to the present invention will be described with reference to the drawings.

An embodiment (Embodiment 1) of a receiver according to the present invention will be described with reference to FIGS. FIG. 1 shows an example of the appearance of the handset 1 (2 in FIG. 1 is a receiver-side end), and FIG. 2 is a diagram showing a schematic cross-sectional configuration of the receiver-side end 2 including the receiver.
A receiver 10 shown in FIG. 2 has a speaker 20 and a front air chamber 30 at the receiver-side end 2 of the handset 1. In the speaker 20, a diaphragm 22 is attached to one surface of the substrate 21 with a spacer 23 interposed therebetween, a coil 24 a is attached to the surface of the diaphragm 22 opposite to the substrate 21, and a magnetic part is attached to the center of the substrate 21. A circuit 24b is attached (the diaphragm is vibrated when the magnetic circuit 24b vibrates the coil 24a). The front air chamber 30 has a diaphragm 22 of the speaker 20 on one end side as a sound source side wall portion, and has an earpiece wall portion 31 positioned in parallel with the diaphragm 22 at a distance of 3 mm on the other end side. A front air chamber space 30a (substantially cylindrical space) is formed by the earpiece wall portion 31 and the peripheral wall 32 (inner diameter 25 mm) having an annular cross section.

  On the inner surface 31c (surface on the front air space 30a side) of the earpiece wall portion 31, an internal opening 31b of each sound hole 31a whose center is located on the sound hole array circle C is opened. The sound hole array circle C includes a first circle (closed curve) C1 that defines the outer shape of the inner surface 31c of the earpiece wall portion 31, and a concentric circle (center of gravity position is the same position) as the first circle C1. The first circle C1 and the second circle C2 are concentrically located between the first circle C1 and the second circle C2, which is half the length of one circle C1. Thus, the earpiece wall portion 31 is closed at the central portion having an area of at least a quarter, and the sound hole 31a (diameter of 2 mm, the number of holes) is arranged in the vicinity of the peripheral wall 32. 20). The rear chamber container 41 is attached to the outer casing 1a of the handset 1 with a screw (not shown), for example, and sandwiches the substrate 21 of the speaker 20 together with the peripheral wall 32, and the substrate 21 (the magnetic circuit 24b is attached to the center). Are interposed between the front air chamber space 30a and the rear air chamber space 40a together with the diaphragm 22.

  In the receiver 10 having such a configuration, the sound wave emitted from the diaphragm 22 of the speaker 20 propagates through the front air chamber space 30a toward each internal opening 31b (broken arrow in FIG. 2), and from each sound hole 31a. Outputs externally to stimulate human hearing. Accordingly, since the sound waves traveling toward the respective internal openings 31b only touch each other in a very narrow region (region R indicated by a dashed ellipse in FIG. 2) near the center of the diaphragm 22, the sound waves are less likely to collide with each other. Therefore, the turbulence of the airflow is reduced (the attenuation of the sound wave in the high frequency region is reduced).

  FIG. 4 is an example of frequency vs. sound output characteristics of the handset 10. The broken line L1 is an example of the frequency versus sound output characteristic of the conventional handset shown in FIG. 5, and the frequency versus sound output characteristic (solid line L2) of the handset 10 is the turbulence of the airflow between the sound waves in the front air chamber space 30a. Therefore, the sound output in the vicinity of 10 kHz increases by 5 to 6 dB, and the frequency characteristic from the middle frequency to the vicinity of fr (10 kHz) in the high frequency region approaches a flat characteristic.

Next, based on FIG.3 and FIG.4, another Example (Example 2) of the receiver concerning this invention is described. In addition, the same code | symbol is attached | subjected to the component which has a function similar to Example 1, and the description is abbreviate | omitted.
The receiver 10a shown in FIG. 3 has a concave curved surface 31d formed on the inner surface 31c of the earpiece wall 31. The concave curved surface 31d and the convex curved surface 22a of the diaphragm 22 of the speaker 20 are complementary curved surfaces. Are formed in a region defined by a third circle (closed curve) C3 having a diameter of 16 mm and the same center as the first circle C1. The center of the convex curved surface 22a has a height of 1 mm in the direction of the earpiece wall 31. Here, the diaphragm 22 and the earpiece wall 31 have an interval of 1 mm in the axial direction of the front air chamber space 30a in any region including the regions of the convex curved surface 22a and the concave curved surface 31d. The internal opening 31b of each sound hole 31a is provided on a sound hole array circle C (a concentric circle with the first circle C1) located in a region outside the third circle (closed curve) C3 (region near the peripheral wall 32). It has been.

  Therefore, the sound wave emitted by the speaker 20 has a propagation path in the axial direction of the front air chamber space 30a from the center of the diaphragm 22 (center of the convex curved surface 22a) to each internal opening 31b, as indicated by a broken line arrow in FIG. It propagates through a radial propagation path at regular intervals without becoming wide or narrow, and is output to the outside from each sound hole 31a to stimulate human hearing. In such a receiver 10a, the turbulence of the airflow occurs only in the vicinity of the center of the convex curved surface 22a of the receiver 10a (region R indicated by a dashed ellipse), and the objectivity of the propagation path from the diaphragm 22 to each internal opening 31b.・ Because the identity is in the best state (because the difference in propagation distance from the diaphragm to each adjacent internal opening 31b can be made zero), the progress of the sound wave is best arranged and the front air chamber space 30a ( The turbulence of airflow in the propagation path) can be minimized.

  As described above, in the receiver 10a, the turbulence of the airflow between the sound waves in the front air chamber space 30a is less than that in the receiver 10, so that the frequency-to-sound output characteristic is 10 kHz as indicated by the one-dot chain line L3 in FIG. In the vicinity, the frequency characteristic is further increased by about 2 to 3 dB as compared with the handset 10, and the frequency characteristics from the middle frequency to the vicinity of fr (10 kHz) in the high frequency region are further flattened.

  The handset according to the invention is not limited to the above embodiments, and can be appropriately modified and implemented without departing from the spirit of the handset. For example, in each of the above embodiments, even when the earpiece wall portion and the sound source side wall portion are not positioned in parallel, each sound wave directed from the diaphragm toward the inner opening of the sound hole is a very narrow region near the center of the diaphragm. Therefore, the turbulence of the airflow between the sound waves is reduced, and the frequency characteristics from the middle frequency to the vicinity of fr in the high frequency region can be flattened. Even if the cross-sectional shape of the peripheral wall of the front air chamber is not circular, the sound waves traveling from the diaphragm toward the inner opening of the sound hole only touch each other in a very narrow area near the center of the diaphragm. Therefore, the frequency characteristic from the middle frequency to the vicinity of fr in the high frequency region can be flattened. Even if the sound holes are not aligned on the sound hole arrangement circle, if each internal opening is located between the first closed curve and the second closed curve, Since the turbulence of the airflow between the sound waves can be reduced, the frequency characteristics from the mid-frequency to the vicinity of fr are flattened.

The example of an external appearance of the handset provided with the receiver concerning this invention is shown. It is a figure which shows schematic sectional structure of the receiver side edge part containing the receiver concerning one Example (Example 1) of this invention. It is a figure which shows schematic cross-sectional structure of the receiver side edge part containing the receiver concerning the other Example (Example 2) of this invention. It is an example of improvement of frequency versus sound output characteristics of the handset according to the present invention. It is a figure which shows the general | schematic cross-section structure of the conventional receiver side edge part.

Explanation of symbols

10, 10a Handset 20 Speaker (electroacoustic transducer)
22 Speaker diaphragm (side wall of sound source)
22a Curved surface of the diaphragm (convex surface)
30 front air chamber 30a front air chamber space 31 earpiece wall 31a sound hole 31b inner opening 31c inner surface 31d inner wall 31d curved surface (concave surface)
32 Peripheral wall C Sound hole arrangement circle C1 1st circle (1st closed curve)
C2 Second circle (second closed curve)
C3 3rd circle (3rd closed curve)

Claims (3)

A front air chamber and an electroacoustic transducer;
The front air chamber has an electroacoustic transducer on one end side and an earpiece wall on the other end side,
The front air chamber space of the front air chamber is defined by a sound source side wall, the earpiece wall, and a peripheral wall,
In the receiver in which sound waves generated by the electroacoustic transducer propagate through the front air space and are output to the outside from a plurality of sound holes provided in the receiver wall,
Any internal opening of the plurality of sound holes,
A first closed curve defining a contour shape of the inner surface of the earpiece wall portion;
A receiver that is located between a second closed curve that is similar to the first closed curve, has a center of gravity at the same position, and has a length that is half the length of the first closed curve. The receiver according to claim 1, further comprising forming a curved surface complementary to a curved surface of the diaphragm of the electroacoustic transducer on the inner surface of the earpiece wall portion, and the inner surface of the earpiece wall portion and the electroacoustic transducer. A sound wave propagation path is formed between the curved surface of the diaphragm of the vessel,
The receiver is characterized in that the inner opening is located outside a third closed curve that defines a contour shape of a curved surface on the inner surface of the earpiece wall.   The handset according to claim 1 or 2, wherein the first closed curve is a circle, and the plurality of sound holes are provided on a sound hole array circle that is concentric with the first closed curve.

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