JPH0833078A - Receiver in communication equipment - Google Patents

Abstract

PURPOSE:To suppress resonance by increasing the acoustic resistance in a hole, to eliminate the generation of a peak in the vicinity of a low-resonance frequency and a high limiting frequency and to flatten a sensitivity frequency characteristic by making the shape of the hole to be formed in an ear piece part a hole shape with a step and increasing the surface area. CONSTITUTION:In a receiver for communication equipment where a receiver is incorporated at the inside, a hole 13 to be formed in an ear piece part 2 is formed into a shape with a step. For instance, the inner side is defined as a large diameter hole part 13a and the outer side is defined as a small diameter hole part 13b. By setting the dimension of each part so that the surf ace area may be larger and the capacity may be almost the same as compared with a conventional straight hole without step, the sharpness of resonance is suppressed low the flattening of a sensitivity frequency characteristic and high sensitivity can be attained and a stable acoustic characteristic can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver in a communication device such as a telephone.

[0002]

2. Description of the Related Art An example of a conventional handset used as a handset of a telephone will be described with reference to FIG. In FIG. 5, a plurality of through holes 3 are formed in the earpiece portion 2 of the earpiece main body 1, and a receiver 4 composed of, for example, an electrodynamic speaker is fixed inside the earpiece portion 2 by fixing its outer peripheral edge. To do. The receiver 4 forms a first front air chamber 6 between the diaphragm 5 and the earpiece 2 of the receiver main body 1, and the first front air chamber 6 is used as the second front air chamber (ear hole) 7 as described above. While communicating through each through hole 3, the first rear air chamber 9 between the diaphragm 5 and the frame 8 is connected to the second rear air chamber 11 inside the handset main body 1 through the plurality of through holes 10 of the frame 8. An acoustic vibration system for communication is provided, and such an acoustic vibration system is used to flatten the sensitivity frequency characteristics of the handset and to increase the sensitivity. When an electric AC signal is applied to the receiver 4, the vibrating plate 5 vibrates, and the sound pressure of the vibrating plate 5 is transmitted from the first front air chamber 6 through the through hole 3 to the second front air chamber. It is led to the ear canal which is 7, and transmitted to humans as a sound.

FIG. 6 is an electrical equivalent circuit showing the structure of the handset of FIG. 5. C6, C7, C9, and C11 are capacitors, which are the first front air chamber 6, the second front air chamber 7, and the second front air chamber 7. It corresponds to the stiffness of the first rear air chamber 9 and the second rear air chamber 11. L3
Represents a coil, and R3 represents resistance, which correspond to the acoustic mass and the acoustic resistance of the through hole 3 which is an acoustic element, respectively. L5 is a coil, R5 is a resistor, and C5 is a capacitor, which correspond to the acoustic mass, acoustic resistance, and stiffness of the diaphragm 5, which is an acoustic element, respectively. L10 represents a coil, and R10 represents resistance, which correspond to the acoustic mass and acoustic resistance of the through hole 10 which is an acoustic element. E indicates a power source, which corresponds to the exciting force (AC signal) applied to the receiver 4.

By the way, in order to flatten the sensitivity frequency characteristic of the handset, various constants of the receiver 4, that is, the effective area, effective mass, and effective stiffness of the diaphragm 5 are determined from the upper limit frequency of the telephone transmission reproduction band. By defining the deviation amount of the sensitivity, the equivalent circuit constant of each part in FIG. 6 is determined.

However, the sharpness of the resonance is determined by the constants of the receiver 4 and the constants of the structure of the receiver main body 1. In the conventional receiver, the value of the sharpness of the resonance becomes large, so that the resonance becomes sharp, There is a problem that flattening of the acoustic characteristics cannot be achieved because it occurs as a peak in the acoustic characteristics.

Therefore, in order to suppress such a peak of the acoustic characteristics, as shown in FIG. 7, there has been conventionally proposed that a nonwoven fabric 12 is attached to the inside of the earpiece portion 2 of the main body 1 of the handset. As shown in FIG. 8, the electrical equivalent circuit of the resistance R12 corresponds to the resistance component of the non-woven fabric 12
Is added.

FIG. 9 is an acoustic characteristic diagram obtained from the receiver shown in FIG. 5, and FIG. 10 is an acoustic characteristic diagram obtained from the receiver shown in FIG. 7. As is clear from a comparison of these acoustic characteristic diagrams. In the handset having the structure shown in FIG. 5, peaks were generated near the low resonance frequency and the high limit frequency, but in the handset having the non-woven fabric 12 shown in FIG. 9, near the low resonance frequency and the high frequency. It is possible to suppress the occurrence of peaks in the vicinity of the band limit frequency and to flatten the sensitivity frequency characteristic. The above acoustic characteristic diagrams are measured by using an electrodynamic speaker as the receiver 4 and a receiver in which six through holes 3 having a diameter of 2 mm and a length of 2 mm are formed in the earpiece 2. As the non-woven fabric 12, two samples cut from the same material having a thickness of 0.5 mm were used, and the acoustic characteristics of each sample are shown in FIG.

[0008]

As described above, in order to flatten the sensitivity frequency characteristics of the handset and to increase the sensitivity, the nonwoven fabric 12 is provided inside the earpiece 2, that is, in the first front air chamber 6.
However, on the other hand, a separate member called a non-woven fabric is needed separately, which causes a cost increase and the stable acoustic characteristics cannot be obtained due to the variation of the non-woven fabric used. A new problem arises. That is, the resistance R12 of the equivalent circuit in FIG.
The value of is determined by the texture of the non-woven fabric 12. Therefore, the value of the resistance R12 also varies due to the variation of the texture, and as a result, from the measurement results using two samples cut from the same material (see FIG. 10). As you can see,
It was supposed to cause variations in acoustic characteristics.

Further, in order to increase the acoustic resistance due to the through holes of the earpiece, it is sufficient to form a large number of through holes having a small diameter.
This complicates the structure of the molding die, causes a cost increase, and cannot be said to be preferable in terms of design.

However, according to the present invention, a non-woven fabric is not used,
(EN) Provided is a handset capable of flattening the sensitivity frequency characteristic and increasing the sensitivity and obtaining stable acoustic characteristics.

[0011]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above-mentioned problems, and in a receiver in a communication device having a receiver inside an earpiece portion having a plurality of through holes, each of the above-mentioned The hole has a stepped hole shape. The stepped hole shape is, for example, such that the inner end has a large diameter.

[0012]

According to the above construction, the surface area of the through hole formed in the earpiece portion is increased, and the viscous resistance to air is also increased accordingly. The same effect as the above can be obtained, that is, the effect that the sensitivity frequency characteristic can be flattened and the sensitivity can be increased. Moreover, since the acoustic resistance in the through hole is determined by the shape of the through hole, the value is stable without variation as in the case of non-woven fabric, and the acoustic characteristics can be stabilized.

When the shape of the through hole is changed, it also affects the acoustic mass, but the volume of the through hole is the largest element that changes the acoustic mass, and the shape of the through hole is If you change the volume so that it does not change,
Since the values of the acoustic mass are almost the same, it is not necessary to consider the influence of the acoustic mass on the acoustic characteristics.

[0014]

Embodiments of the present invention shown in FIGS. 1 to 5 will be described in detail. FIG. 1 is an explanatory diagram showing a main structure of a receiver according to an embodiment of the present invention, and FIG. 2 is an electrical equivalent circuit showing the configuration of the receiver, which are common to FIGS. 5 to 8. Common reference numerals are attached to the parts.

The earpiece according to this embodiment is different from the conventional earpiece shown in FIG. 5 only in the shape of the through hole formed in the earpiece 2, and the other structures are all the same. In this embodiment, the through hole 13 formed in the earpiece 2 has a stepped hole shape, for example, a large diameter hole 13a on the inner side and a small diameter hole 13b on the outer side. By forming the dimensions of each part so that the surface area is increased and the volume is almost the same as compared with the conventional straight through hole 3 having no step, it is formed in the earpiece part 2 in the handset shown in FIG. The sharpness of resonance can be suppressed to a low level by only changing the shape of the through hole, and the sensitivity frequency characteristics can be flattened and the sensitivity can be increased, and stable acoustic characteristics can be obtained.

That is, by increasing the surface area of the through hole 13, the viscous resistance of air to the through hole 13 is increased, and the volume of the through hole 13, which is the largest element that affects the acoustic mass, is made substantially the same. Explaining in the equivalent circuit of FIG. 2, the coil L1 corresponding to the acoustic mass of the through hole 13 which is an acoustic element.
3 is substantially equal to the coil 3 in FIG. 6, and the value of the resistance R13 corresponding to the acoustic resistance is the resistance R3 in FIG.
Set larger than the value of. As a result, it is possible to suppress the generation of peaks in the vicinity of the low resonance frequency and in the vicinity of the high limit frequency, as in the case where the nonwoven fabric is inserted.

FIG. 3 is a diagram showing the acoustic characteristics of the handset according to the present embodiment, in which an electrodynamic speaker is used as the receiver 4, and the diameter of the large diameter hole portion 13a of the through hole 13 is 2.64 mm.
The measurement results when the length is 1 mm, the diameter of the small diameter hole portion 13b is 1 mm, the length is 1 mm, and the number of through holes is 6 are shown. The measurement conditions other than the through hole 13 are the same as the measurement conditions of the acoustic characteristics shown in FIGS. 9 and 10.

According to the receiver according to this embodiment, as can be seen from the measurement results shown in FIG. 3, the occurrence of peaks near the low resonance frequency and the high limit frequency is higher than that of the conventional receiver that does not use the nonwoven fabric. It is possible to achieve flatness of sensitivity frequency characteristics and high sensitivity. Moreover, since the acoustic resistance due to the through holes 13 is determined by the shape thereof, there is no variation like the texture of the non-woven fabric, the acoustic resistance becomes stable, and the stable acoustic characteristics are obtained. Further, by setting the volume of the through hole 13 to a value equal to or approximate to the volume of the conventional through hole 3, it is not necessary to consider the influence of the acoustic mass on the acoustic characteristics.

Next, another embodiment of the present invention will be described. The shape of the through hole formed in the earpiece portion 2 of the earpiece main body 1 is not particularly limited to the shape of the above-described embodiment,
A stepped shape as shown in FIG. 4 may be used. The through hole 14 shown in FIG. 4 has a stepped shape with a large diameter hole portion 14a at both ends and a small diameter hole portion 14b at the middle portion, and when the same effect as that of the previous embodiment is expected. Each large diameter hole 1
4a has a diameter of 2.64 mm and a length of 0.5 mm, and the small diameter hole portion 14b has a diameter of 1 mm and a length of 1 mm.
In the above embodiment, the receiver 4 is an electrodynamic speaker, but a piezoelectric speaker or the like may be used.

[0020]

As described above, in the handset of the present invention, the through hole formed in the earpiece has a stepped hole shape and the surface area is increased to increase the acoustic resistance in the through hole. The sharpness of the resonance is suppressed to eliminate the occurrence of peaks near the low-frequency resonance frequency and the high-frequency limit frequency, and the sensitivity frequency characteristics can be flattened and the sensitivity can be increased, and a separate member such as non-woven fabric is used. It is possible to provide a practically excellent handset that does not need to be used, is excellent in cost, and does not cause variations in acoustic characteristics.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for explaining a main part configuration of a handset according to an embodiment of the present invention.

FIG. 2 is an electrical equivalent circuit diagram showing the configuration of the handset.

[Fig. 3] Acoustic characteristic diagram obtained from the handset

FIG. 4 is an enlarged cross-sectional view of a main part of a receiver according to another embodiment of the present invention.

FIG. 5 is a structural explanatory view showing an example of a conventional handset.

FIG. 6 is an electrical equivalent circuit diagram showing the configuration of the handset.

FIG. 7 is a structural explanatory view showing another example of a conventional handset.

FIG. 8 is an electrical equivalent circuit diagram showing the configuration of the handset.

FIG. 9 is an acoustic characteristic diagram obtained from the handset shown in FIG.

FIG. 10 is an acoustic characteristic diagram obtained from the handset shown in FIG.

[Explanation of symbols]

 1 Earpiece main body 2 Earpiece section 4 Receiver 5 Vibration plate 6 First front air chamber 7 Second front air chamber (ear hole) 9 First rear air chamber 11 Second rear air chamber 13,14 Through hole 13a, 14a Large diameter hole Portion 13b, 14b Small hole portion

Claims (2)

[Claims] 1. A receiver in a communication device having a receiver inside a receiver having a plurality of through holes, wherein each of the through holes has a stepped hole shape. 2. The handset in a communication device according to claim 1, wherein the stepped hole shape is a shape in which the inner end has a large diameter.