JP3557361B2 - Electroacoustic transducer for receiving - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a receiving electro-acoustic transducer used for a handset of a mobile phone or the like.
[0002]
[Prior art]
Conventionally, as measures to improve the acoustic characteristics of the receiving side of a mobile phone, measures to prevent sound from leaking into the case of the mobile phone (pre-leak in the case), and to attach the earpiece of the handset case to the auricle to listen. Measures to be taken are taken.
[0003]
[Problems to be solved by the invention]
However, in the structure that takes measures against pre-leakage in the case, sound was emitted inside the case of the handset, so the separation characteristics that prevent howling due to the sound sneaking between the microphone on the transmitting side and the receiver on the receiving side also had The isolation characteristics to be referred to are not good. Therefore, in order to improve the isolation characteristics, it is necessary to take extra measures such as providing a partition for partitioning the inside of the handset case into a transmitting side and a receiving side.
[0004]
In addition, in the case of a closed type in which the earpiece of the case is brought into close contact with the auricle to listen to the sound, if sound leakage occurs in the auricle part, the frequency characteristics will change significantly, and in order to reduce the change, Has adopted means for securing a large volume in the back chamber of the diaphragm of the receiver (electroacoustic transducer) on the receiving side.
[0005]
By the way, in the mobile phone which has become popular recently, the above-mentioned partition has been added due to the progress of miniaturization so that it can be conveniently carried in a pocket or bag of clothes. Or increasing the volume of the back chamber of the diaphragm is not preferred because it hinders miniaturization. In addition, it is difficult for small-sized hermetically sealed mobile phones to perform the operation of listening to the incoming call sound by attaching the earpiece of the case to the pinna exactly. The earpiece is kept slightly away from the pinna. For this reason, during actual use, sound leakage occurs between the ear cover and the pinna of the case, and the frequency characteristics change, making it difficult to hear particularly low-frequency band sounds.
[0006]
The present invention has been made under the above circumstances, and without the need to increase the volume of the back chamber of the diaphragm, it is possible to hear the sound when the auricle is perfectly fitted to the ear pad of the case. It is an object of the present invention to provide a receiving electro-acoustic transducer in which the difference between the sound-receiving characteristic (sealing characteristic) and the way in which sound is heard when the earpiece is separated from the pinna (pre-leak characteristic) is reduced.
[0007]
In addition, the present invention provides a receiving electro-acoustic transducer in which the acoustic characteristics in a predetermined frequency band are kept almost flat and the sound in a low frequency band is easily heard in any of the above two cases. The purpose is to:
[0008]
Still another object of the present invention is to provide a receiving electro-acoustic transducer capable of improving the above-mentioned isolation characteristics without providing a partition between a transmitting side and a receiving side of a case of a handset. I do.
[0009]
[Means for Solving the Problems]
The receiving electro-acoustic transducer according to the present invention includes a diaphragm having a magnetic circuit forming element, a voice coil inserted into a gap in the magnetic circuit, and disposed in front of the magnetic circuit forming element. An electroacoustic transducer provided with a sound-permeable baffle plate disposed on the front side of the plate, and having a shielding member housed in the case and blocking sound leakage from the electroacoustic transducer to the back. And a surrounding wall member surrounding a space between the baffle plate and the magnetic circuit forming element, and a sound is provided on an outer peripheral portion of an earpiece having a sound hole provided in the case facing the baffle plate. A leak passage is formed, and a sound output passage communicating the sound leak passage with a back room partitioned by the diaphragm in the space via a communication passage is provided in the enclosure wall member, and the baffle plate is provided. A sound return passage for returning a part of the sound emitted to the front side to the back chamber through the communication passage and the sound output passage is formed by the baffle plate and the ear cover portion, and the baffle plate and the ear cover portion There is a flexible pad between them.
[0010]
In the present invention, the shielding member is fitted to the back plate of a frame provided in the case and having a back plate and a peripheral wall integral with the back plate, and a fitting hole provided in the back plate. And the magnetic circuit forming element of the electroacoustic transducer provided. Further, the enclosing wall member is formed by a peripheral wall of the frame in which one portion in the circumferential direction is cut off, and a cap that is fitted into a cut-out portion of the peripheral wall and closes the cut-off portion. It is possible to form a sound output passage.
[0011]
The operation of the present invention will be made clear by the following description of the embodiments.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is an exploded perspective view showing an essential part of an embodiment of a receiving electro-acoustic transducer according to the present invention, and FIG. 2 is a sectional view showing an essential part of the apparatus.
[0013]
1 and 2, an electroacoustic transducer 10 used as a receiver has a magnetic circuit forming element 20 and a voice coil 31 inserted into a gap G in the magnetic circuit. The diaphragm 30 includes a diaphragm-type diaphragm 30 disposed in front of the diaphragm 30, a baffle plate 40 having sound permeability disposed in front of the diaphragm 30, a frame 50, and a pad 60. The electroacoustic transducer 10 employs a low acoustic impedance electroacoustic transducer.
[0014]
The magnetic circuit forming element 20 has a disk-shaped magnet 21, a circular yoke 22 and a disk-shaped pole piece 23 that are distributed to both poles of the magnet 21. 23, the gap G is formed. The baffle plate 40 is made of a circular metal plate, and has a sound emission hole 41 at an eccentric portion thereof. The frame 50 is a synthetic resin molded body having a back plate 51 and a peripheral wall 52 integral with the back plate 51, and the magnetic circuit forming element 20 is fitted in a mounting hole 53 provided in the back plate 51. Attached to. Further, the peripheral wall 52 is cut at one position in the circumferential direction, and the cut portion is closed by an arc-shaped cap 54 attached to the cut portion. An outer peripheral edge of the diaphragm 30 and an outer peripheral edge of the baffle plate 40 are supported by a circular surrounding wall member 55 (described later) formed by the peripheral wall 52 and the cap 54. Further, coil spring-type terminal terminals 56 and 57 are attached to a flat portion 58 provided on the outer peripheral portion of the frame 50, and the lead wires 32 drawn out from the voice coil 31 are attached to these terminal terminals 56 and 57. , 33 are separately connected. As shown in FIG. 1, the pad 60 integrally has an edge frame 61 made of a flexible material and a flexible net 62 having a fine mesh covering an opening formed by the edge frame 61. As shown in FIG. 2, the pad 60 has an edge frame 61 adhered to the frame 50 with an adhesive, covers the baffle plate 41, and is folded over the flat portion 58.
[0015]
The electroacoustic transducer 10 having the above configuration is incorporated as a unit into a case 70 of a handset of a mobile phone as shown in FIG. 2, and in the assembled state (accommodated state), the terminal terminals 56 and 57 are connected to the case 70. Is resiliently contacted with the electrode of the wiring board 80 in the inside. When the pad 60 is in contact with the back surface of the ear cover 71 provided on the case 70, the pad 60 is arranged between the baffle plate 40 and the ear cover 71. The earpiece 71 faces the baffle plate 40 and has sound holes 74 at two places in the center.
[0016]
In the electroacoustic transducer described with reference to FIGS. 1 and 2, the back plate 51 of the frame 50 provided in the case 70 and the electroacoustic transducer 10 attached to the mounting hole 53 of the back plate 50 are provided. The shielding member 90 is formed by the magnetic circuit forming element 20. This shielding member 90 has a function of blocking sound leakage from the electroacoustic transducer 10 to the back. Further, the circular surrounding wall member 55 formed by the peripheral wall 52 of the frame 50 and the cap 54 surrounds the space between the baffle plate 40 and the magnetic circuit forming element 20 around the surrounding wall member 55.
[0017]
An outward sound leakage passage 72 is provided in the outer peripheral portion of the earpiece 71, whereas a sound output passage 59 is provided in the cap 54 forming the surrounding wall member 55. The outlet passage 59 communicates with a back room in a space surrounded by the surrounding wall member 55, that is, the back room 34 partitioned by the diaphragm 30. Further, the communication passage 73 formed by the clearance space between the surrounding wall member 55 and the outer peripheral portion of the ear contact portion 71 is formed of the sound leakage passage 72 facing each other with the communication passage 73 interposed therebetween. The start portion 72a communicates with the end portion 59a of the sound output passage 59.
[0018]
FIG. 2 shows only the receiving-side electro-acoustic transducer provided at one end of the case 70, but the transmitting-side electro-acoustic transducer is provided at the other end of the case 70.
[0019]
According to this electro-acoustic transducer, sound leakage into the case of the sound generated by the electro-acoustic transducer 10 is blocked by the shielding member 90, so that howling due to sound wraparound between the receiving side and the transmitting side is performed. Will be prevented. Therefore, the isolation characteristics are improved.
[0020]
Further, the sound of the back chamber 34 of the diaphragm 30 leaks from the back chamber 34 to the outside of the case 70 through the sound output passage 59 and the communication passage 73 and then passes through the sound leakage passage 72 as shown by arrows a and b. Get out. As a result, the frequency characteristics are improved, the acoustic characteristics in the predetermined frequency band are kept almost flat, and the sound in the low frequency band is easily heard. Further, a part of the sound once emitted to the front side of the baffle plate 40 passes through a sound return passage 75 formed by a gap between the baffle plate 40 and the ear cover 71 of the case 70 as shown by an arrow c. It reaches the passage 73 and further returns to the back room 34 of the diaphragm 30 through the sound output passage 59. Thus, the degree of sealing between the earpiece 71 and the pinna does not adversely affect the frequency characteristics.
[0021]
In this electroacoustic transducer, since the baffle plate 40 and the pad 60 cover the diaphragm 30 and the like, there is an advantage that a dustproof action is exerted by them.
[0022]
Next, the acoustic characteristics of the electroacoustic transducer according to the present invention will be described with reference to FIGS. 3 to 8 and 9 to 11 together with comparative examples. The acoustic characteristics are quantitatively measured by installing a frequency characteristic measuring jig in the electroacoustic transducer.
[0023]
3 to 8, reference numeral 1 denotes a measurement jig, which has an artificial ear 2 and a microphone 3 for collecting sound. Reference numeral 4 denotes a leakage ring having a sound leakage hole 5.
[0024]
3, 5, and 7 illustrate the case where the artificial ear 2 of the measurement jig 1 is pressed against the ear cover 71 of the case 70 to surround the sound hole 74 of the ear cover 71, so that the ear cover 71 and the artificial ear 2 shows a measurement method performed so as not to cause sound leakage from a gap between the first and second samples. This measurement method is a simulation mode in which the earpiece 71 of the case 70 is fitted to the pinna so as not to cause sound leakage, and the reception sound is heard, and is suitable for basic measurement of frequency characteristics. . On the other hand, FIG. 4, FIG. 6, and FIG. 8 show a measurement method performed by using the leakage ring 4 to cause sound leakage between the earpiece 71 and the artificial ear 2. This measurement method is a simulated mode when listening to a reception sound in a state where the auricle is away from the ear pad 71, and is in a more actual use state of the mobile phone than in the case of FIGS. 3, 5 and 7. Frequency characteristics can be quantitatively measured in a close state. Hereinafter, the frequency characteristics obtained by the measurement methods of FIGS. 3, 5, and 7 are referred to as closed characteristics, and the frequency characteristics obtained by the measurement methods of FIGS. 4, 6, and 8 are referred to as pre-leak characteristics.
[0025]
FIG. 3 shows a method for measuring the sealing characteristics of the receiving-side electroacoustic transducer according to the present invention, and FIG. 4 shows a method for measuring the pre-leakage characteristics of the device. FIG. 5 shows a method of measuring the sealing characteristics of the receiving-side electroacoustic transducer according to the first comparative example, and FIG. 6 shows a method of measuring the pre-leakage characteristics of the device. FIG. 7 shows a method for measuring the sealing characteristics of the receiving-side electroacoustic transducer according to the second comparative example, and FIG. 8 shows a method for measuring the pre-leakage characteristics of the device. 9 shows the acoustic characteristics of the receiving-side electro-acoustic converter according to the present invention, FIG. 10 shows the acoustic characteristics of the receiving-side electro-acoustic converter according to the first comparative example, and FIG. 11 shows the acoustic characteristics of the second comparative example. The acoustic characteristics of the receiving-side electroacoustic transducer are shown respectively. In FIGS. 9 to 11, the solid line indicates the closed characteristic, and the broken line indicates the pre-leak characteristic curve. The difference between the receiving-side electroacoustic transducer according to the present invention and the first and second comparative examples is that, in the first comparative example, one of the two sound holes 74 of the earpiece 71 is used. In the second comparative example, the sound output hole 59 of the surrounding wall member 55 is closed. In other respects, the receiving-side electro-acoustic converter according to the present invention and the first and second comparative examples have the same configuration.
[0026]
According to FIG. 10 showing the acoustic characteristics of the first comparative example, although the sensitivity of the sealing characteristics shows a high value of about 110 dB in a low frequency band (around 100 to 500 Hz), the sensitivity drops sharply at 1 to 2 kHz. It is not satisfactory in terms of flatness of the sealing characteristics. The sensitivity of the pre-leak characteristic is about 90 dB, and a certain level of flatness is maintained. However, the difference H between the sealing characteristic and the pre-leak characteristic on the low frequency side of 1 kHz or less is large. This means that the sound in the low frequency band that can be heard when the pinna is attached to the earpiece 71 to prevent sound leakage at the pinna portion, It indicates that it becomes extremely hard to hear.
[0027]
According to FIG. 11 showing the acoustic characteristics of the second comparative example, the sensitivity of the sealing characteristics is close to 90 dB on the low frequency side of 1 kHz or less, and a certain degree of flatness is maintained. The sensitivity of the pre-leak characteristic sharply decreases at lower frequencies in a band of 1 kHz or less. For this reason, the difference H between the sealing characteristic and the pre-leak characteristic on the low frequency side of 1 kHz or less rapidly increases as the frequency decreases. Therefore, also in this case, the sound in the low frequency band that can be heard when the pinna is properly attached to the ear pad 71 so as not to cause sound leakage at the pinna portion, the sound leak occurs at the pinna portion. Indicates that it becomes extremely hard to hear when
[0028]
According to FIG. 9 showing the acoustic characteristics of the receiving-side electro-acoustic transducer according to the present invention, the sensitivities of the sealing characteristic and the pre-leak characteristic are close to each other on the low frequency side of 1 kHz or less, and both fall within the range of 90 to 95 dB. In addition, the sensitivity of the sealing characteristic and the sensitivity of the pre-leak characteristic both maintain flatness. The difference H between the two characteristics on the low frequency side is reduced to a small value. This is due to the fact that low-frequency band sound can be heard when the pinna is attached to the earpiece 71 so as not to cause sound leakage at the pinna portion, and sound leakage occurs at the pinna portion. In this case, there is little difference from how to hear the sound in the low frequency band that can be heard when the sound is on, indicating that the sound is easy to hear in any case.
[0029]
In the above-described embodiment, the low acoustic impedance dynamic receiver is used as the electroacoustic transducer 10. However, when the high acoustic impedance dynamic receiver is used as the electroacoustic transducer 10, both the sensitivity of the sealing property and the sensitivity of the pre-leak property are low. Although it is lower than that of FIG. 9 on the low frequency side, it has been confirmed that the difference H between the two characteristics on the low frequency side is reduced to a small value and the flatness of the sensitivity is secured.
[0030]
【The invention's effect】
As described above, according to the present invention, the difference between the sealing characteristic and the pre-leak characteristic is reduced and the acoustic characteristic in a predetermined frequency band is reduced without increasing the volume of the back chamber of the diaphragm.ゞ Because it is kept flat, it is easier to hear low frequency band sounds. Further, according to the present invention, it is possible to improve the isolation characteristics without providing a partition between the transmitting side and the receiving side of the case.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a main part of an embodiment of a receiving electro-acoustic transducer according to the present invention.
FIG. 2 is a cross-sectional view illustratively showing a main part of the receiving electro-acoustic transducer.
FIG. 3 is an explanatory diagram showing a method of measuring the sealing characteristics of the receiving-side electro-acoustic transducer according to the present invention.
FIG. 4 is an explanatory diagram showing a method of measuring a pre-leak characteristic of the receiving-side electro-acoustic transducer according to the present invention.
FIG. 5 is an explanatory diagram showing a method for measuring sealing characteristics of a first comparative example.
FIG. 6 is an explanatory diagram showing a method of measuring a pre-leak characteristic of a first comparative example.
FIG. 7 is an explanatory diagram showing a method for measuring sealing characteristics in a second comparative example.
FIG. 8 is an explanatory diagram showing a method of measuring a pre-leak characteristic of a second comparative example.
FIG. 9 is a diagram showing acoustic characteristics of the receiving-side electro-acoustic transducer according to the present invention.
FIG. 10 is a diagram illustrating acoustic characteristics of a first comparative example.
FIG. 11 is a diagram illustrating acoustic characteristics of a second comparative example.
[Explanation of symbols]
Reference Signs List 10 electroacoustic transducer 20 magnetic circuit forming element 30 diaphragm 31 voice coil 34 back room 40 baffle plate 50 frame 51 back plate 52 peripheral wall 53 mounting hole 54 cap 55 surrounding wall member 59 sound output passage 59a end portion of sound output passage 60 Pad 70 Case 71 Earpiece 72 Sound leak passage 72a Sound leak passage start 73 Communication passage 74 Sound hole 75 Sound return passage 90 Shielding member G Gap

Claims (3)

A magnetic circuit forming element, a diaphragm having a voice coil inserted into a gap in the magnetic circuit and disposed in front of the magnetic circuit forming element, and having a sound permeability disposed in front of the diaphragm A baffle plate, and an electro-acoustic transducer, which is housed in the case and has a shielding member for blocking sound leakage from the electro-acoustic transducer to the back, and the baffle plate and the magnetic circuit forming element. A sound leakage passage is formed in an outer peripheral portion of an earpiece portion having a sound hole provided in the case facing the baffle plate, and a sound leakage passage formed between the sound leakage passage and the sound leakage passage. A sound output passage communicating the back room partitioned by the diaphragm in the space through a communication passage is provided in the enclosure wall member, and a part of the sound emitted to the front side of the baffle plate is partially connected to the communication passage and Up A sound return passage returning to the back chamber through a sound output passage is formed by the baffle plate and the earpiece, and a flexible pad is provided between the baffle plate and the earpiece. A receiving electro-acoustic transducer. The back plate of the frame, wherein the shielding member is mounted on the case and has a back plate and a peripheral wall integral with the back plate; and the electric member fitted to a mounting hole provided in the back plate in a fitting manner. 2. The receiving electro-acoustic transducer according to claim 1, wherein the electro-acoustic transducer is formed by the magnetic transducer forming element of the acoustic transducer. The surrounding wall member is formed by a peripheral wall of the frame in which one portion in the circumferential direction is cut off, and a cap that is fitted into a cut-out portion of the peripheral wall and closes the cut-off portion. 3. The receiving electro-acoustic transducer according to claim 2, wherein a sound output passage is formed.

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