JP4408287B2 - Handset - Google Patents

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, a front air chamber is provided on the front side of an electroacoustic transducer (for example, a speaker, which may be simply referred to as “speaker” hereinafter), and the receiver is received through a sound hole provided in the earpiece of the front air chamber. The technology to improve the frequency-to-sound output characteristics of the handset by improving the frequency-to-sound output characteristics of the handset and providing a rear air chamber with a leak hole behind the speaker diaphragm is developed. (For example, Patent Documents 1 and 2).
JP-A-10-150698 JP 2003-23482 A

  However, since the frequency-to-sound output characteristics of the handset are determined by the volume of the tubular body of the handset including the front air chamber and the rear air chamber (for example, Patent Document 1), a leak hole is provided in the rear air chamber to reduce the volume. Even if the acoustic output characteristics in any one of the frequency bands of the frequency band, the middle frequency range, and the high frequency range can be changed (to a desired characteristic), the frequency-to-sound output characteristics can be flattened over a wide frequency range. Can not. Further, a technique (for example, Patent Document 2) that uses a phase difference between a sound wave generated toward the front surface of the speaker and a sound wave generated toward the back surface of the speaker has a desired acoustic output characteristic in the vicinity of a frequency at which the phase difference can be used. Therefore, the frequency-to-sound output characteristic cannot be flattened over a wide frequency range. Therefore, an object of the present invention is to realize a receiver that can flatten the frequency-to-sound output characteristics over a wide frequency range.

  In order to solve the above problems, a receiver according to the present invention has an electroacoustic transducer, a front air chamber, and a rear air chamber as described in claim 1, and the front air chamber has an electroacoustic sound at one end side. The transducer has the earpiece wall on the other end, and the front air space of the front air chamber is defined by the sound source front wall, the earpiece wall, and the peripheral wall, and the rear air chamber is the back of the sound source. A sound wave generated by the electroacoustic transducer is separated from a plurality of sound holes provided in the earpiece wall portion by defining a rear air chamber space having a wall portion and a rear air chamber body, and being generated by the electroacoustic transducer. In the receiver output to the outside, the first leak hole and the second leak hole of the rear air chamber main body leak sound waves generated by the diaphragm of the electroacoustic transducer to the outside of the receiver. The opening of the first leak hole is covered with a damper material.

  If there is no leak hole in the rear air chamber body that defines the rear air chamber space, the sound output of the handset decreases in the low frequency region, and the sound output increases in the middle frequency region (for example, around 3 to 5 kHz). The sound output decreases from the mid-frequency range to the high-frequency range (for example, 5 to 10 kHz). Therefore, the handset first provides a first leak hole to increase the sound output of the handset in the low frequency range. However, if only the first leak hole is provided, the sound output in the middle frequency region remains increased, and the frequency-to-sound output characteristic cannot be flattened.

  Therefore, the opening of the first leak hole is covered with a damper material on the outer surface of the rear air chamber body, and acts as a damper against acoustic resonance in the rear air chamber space. With this damper action, the sound output at the mid-range frequency, which is the acoustic resonance frequency, decreases, and the rate of increase / decrease of the sound output with respect to the frequency change in the region near the mid-range frequency decreases, and the sound output increases. The area (band) can be expanded. However, a part of the sound output of the handset in the low frequency region is reduced by this damper action. Therefore, a second leak hole is further provided to increase the sound output in the low frequency region with the second leak hole.

  Thus, in the low frequency range, the sound output is increased by the first leak hole and the second leak hole, and the sound output in the mid frequency range is flattened over a wide frequency range by the damper action of the first leak hole. Is done. Therefore, the handset can realize a good frequency-to-sound output characteristic from the low-frequency range to the middle to high-frequency range (the frequency-to-sound output property can be widened).

  The receiver according to claim 2 is configured such that the damper action of the first leak hole is eliminated by the second leak hole by making the diameter of the second leak hole smaller than the diameter of the first leak hole. By preventing the sound output in the frequency domain from increasing again, the frequency-to-sound output characteristic of the handset can be further improved.

  As described above, the handset according to the present invention can increase the sound output in the low frequency range by providing the first leak hole and the second leak hole, and the first cover whose opening is covered with the damper material. The leak holes can flatten the sound output characteristics in the mid-frequency range. Therefore, the handset according to the present invention can flatten the frequency-to-sound output characteristics from the low-frequency range to the mid- to high-frequency range (the frequency-to-sound output property can be increased).

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

  An embodiment of a handset 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 a receiver 10 provided in the receiver-side end 2. The receiver 10 according to the present invention includes a speaker 20, a front air chamber 30, and a rear air chamber 40 at the receiver side end 2 of the handset 1.

  In the speaker 20, the diaphragm 22 is attached to one side of the substrate 21 with a spacer 23 interposed therebetween, and the speaker internal space 25 formed between the diaphragm 22 and the substrate 21 has a spacer 23 around the periphery thereof. A coil 24a is attached to the surface of the diaphragm 22 on the side of the speaker internal space 25, and a magnetic circuit 24b is attached to the center of the substrate 21 (the magnetic circuit 24b vibrates the coil 24a). The vibration plate vibrates.) Further, in the speaker 20, in order to smoothly vibrate the diaphragm 22, a speaker leak hole 21 a is provided in the substrate 21, and the speaker internal space 25 and the rear air chamber space 40 a communicate with each other. Air vibration generated in the speaker internal space 25 is leaked to the rear air chamber space 40a.

  The front air chamber 30 has a diaphragm 22 of the speaker 20 on one end side as a sound source front wall portion, and has an earpiece wall portion 31 positioned parallel to the diaphragm 22 at a distance of 3 mm on the other end side. The earpiece wall portion 31 and the peripheral wall 32 (inner diameter 25 mm) having an annular cross section form a front air chamber space 30a (substantially cylindrical space). The earpiece wall 31 is provided with 24 sound holes 31a having a diameter of 2 mm. Therefore, in the receiver 10, sound waves generated by the speaker 20 propagate through the front air chamber space 30 a and are output to the outside from the plurality of sound holes 31 a provided in the receiver wall 31, thereby stimulating human hearing.

  The substrate 21 of the speaker 20 (the magnetic circuit 24b is attached at the center) and the bottomed cylindrical rear air chamber body 41, which form the sound source rear wall of the rear air chamber 40, are the rear air chamber space 40a. Is drawn. A first leak hole 42 (diameter 3 mm) and a second leak hole 43 (diameter 1.5 mm) are respectively provided in the bottom surface portion 41a of the rear air chamber main body 41 (the first leak hole 42 and the first leak hole 42). The second leak hole 43 can be provided at any position on the bottom surface portion 41a), and a damper material 44 is attached to the outside of the first leak hole 42. The damper material 44 is, for example, a cloth having a fine texture or a mesh for screen printing, and acts as a damper with respect to acoustic resonance in the rear air space 40a by air resistance of the fine texture. The rear air chamber main body 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 (the substrate 21 together with the diaphragm 22 is in the front air chamber). It is interposed between the space 30a and the rear air chamber space 40a).

  FIG. 3 is an example of frequency versus sound output characteristics of the receiver 10 (the horizontal axis is frequency and the vertical axis is sound output). The broken line L1 is a frequency versus sound output characteristic when the rear air chamber space 40a does not have a leak hole. When there is no leak hole in the rear air chamber body, the frequency vs. acoustic output characteristic curve in the low frequency range falls toward the low frequency side, and the acoustic output in the mid frequency range (for example, around 3 to 5 kHz). Increases by about 10 dB. Here, when the first leak hole 42 is provided, the acoustic output in the low frequency region is increased by the action of the first leak hole 42 as shown by a one-dot chain line L2, and the frequency versus sound in the low frequency region is increased. The output characteristic curve is flattened (the middle frequency region where the sound output increases is slightly lowered to 2 to 3 kHz). However, the degree of increase in the sound output in the mid-frequency range in the alternate long and short dash line L2 is not much different from the degree of increase in the sound output in the mid-frequency range in the broken line L1.

  Therefore, when the opening 42a of the first leak hole 42 is covered with the damper material 44 on the outer surface of the rear air chamber main body 40a, the damper material 44 acts as a damper against acoustic resonance in the rear air chamber space 40a. When the damper material 44 acts on the acoustic resonance, as indicated by a two-dot chain line L3, the acoustic output at the acoustic resonance frequency (middle frequency) decreases, and the increase or decrease in the acoustic output with respect to the frequency change in the region near the middle frequency. As the rate decreases, the middle frequency region (band) in which the acoustic output increases increases (the acoustic output flattens from the middle to the wide frequency region), but the acoustic output in the middle frequency region is low frequency region It is still about 3 to 5 dB higher than.

  Therefore, if the second leak hole 43 is further provided, the sound output in the low frequency range is increased, so that the sound output is flattened from the low frequency range to the middle to wide frequency range (solid line L). Here, if the diameter of the second leak hole 43 is too large, the effect of the damper of the first leak hole 42 is extinguished, and the characteristic of the alternate long and short dash line L2 is restored. When the size is smaller than the leak hole 42, the sound output is not increased in the mid-frequency range than when the diameters of both the leak holes are equal.

  Thus, in the receiver 10, the sound output in the low frequency region is increased by the first leak hole 42 and the second leak hole 43, and due to the action of the damper material 44 attached to the opening 42 a of the first leak hole 42. The degree of increase in the sound output in the mid-frequency range is flattened, and the increase in the sound output is flattened over a wide frequency range. Therefore, the handset 10 can realize good frequency-to-sound output characteristics from the low-frequency range to the middle to high-frequency range (the frequency-to-sound output property can be widened).

  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 the above embodiment, even if the rear air chamber space has a shape other than the bottomed cylindrical shape, the first leak hole and the second leak hole can increase the acoustic output in the low frequency range. In addition, the damper material expands the mid-frequency region where the sound output increases to the vicinity of the low-frequency region and the vicinity of the high-frequency region, and also exhibits the effect of flattening the increase in sound output over a wide frequency region. The same operational effects as in the above embodiment are obtained. Further, the number of the first leak holes and the second leak holes is not limited in the above embodiment.

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 cross-sectional structure of the receiver side edge part containing the receiver concerning one Example of this invention. It is a characteristic view which shows the mode of the improvement of the frequency versus sound output characteristic of the receiver concerning a figure.

Explanation of symbols

10 Handset 20 Speaker (electroacoustic transducer)
21 Speaker board (sound source back wall)
22 Speaker diaphragm (front wall of sound source)
30 front air chamber 30a front air chamber space 31 earpiece wall portion 31a sound hole 32 peripheral wall 40 rear air chamber 40a rear air chamber space 41 rear air chamber body 42 first leak hole 43 second leak hole 44 damper material

Claims (2)

An electroacoustic transducer, a front air chamber, and a rear air chamber;
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 front wall portion, the earpiece wall portion, and a peripheral wall,
The rear air chamber has a sound source back wall and a rear air chamber body to define a rear air chamber space,
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,
The first leak hole and the second leak hole of the rear air chamber main body leak sound waves generated by the diaphragm of the electroacoustic transducer to the outside of the rear air chamber of the receiver,
The receiver according to claim 1, wherein an opening of the first leak hole is covered with a damper material.   The handset according to claim 1, wherein the diameter of the second leak hole is smaller than the diameter of the first leak hole.

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