JP2006066972A - Speaker device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speaker device mainly employing bone conduction and capable of being used in various environments. <P>SOLUTION: The speaker device is provided with a piezoelectric vibrator 11, a pressure sensor 12 for detecting a pressing force between the piezoelectric vibrator 11 and a vibration transmitter for pressing this piezoelectric vibrator 11, and a vibration output control means for increasing the vibration output of the piezoelectric vibrator 11 in response to the increase in the pressing force. Also, the piezoelectric vibrator 11 is supported by a supporter 13, and the pressing sensor 12 is attached on the supporter 13. Further, the pressure sensor is configured so that it has high sensitivity for static pressure and low sensitivity in a sound frequency band. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a speaker device, and more particularly to a speaker device suitable for using a piezoelectric vibrator as an acoustic vibration generator in various usage environments.

  It is well known that a speaker with high conversion efficiency can be obtained when a piezoelectric vibrator is used as an acoustic vibration generator. One such speaker device is a bone conduction type speaker device. This type of speaker device is also used in, for example, mobile phones. According to this technology, a speaker device configured to block ambient sounds transmitted through the external auditory canal and cause the auditory organs of the inner ear to perceive sound vibration by bone conduction of the human head is used. The sound can be heard without being disturbed by the sound. Therefore, the speaker can be used even in an environment with a high noise level such as a transportation platform. For example, as disclosed in Patent Document 1, a mobile phone including a bone-conduction speaker is an example.

  In the above-described prior art, when the external auditory canal entrance is closed to block external noise and a bone conduction only transmission path is used, it cannot be said that the S / N ratio of voice vibration reaching the inner ear is sufficiently high, There is also a sense of ear closure by closing the ear canal entrance.

  In general, when a bone conduction type speaker device is used, in an environment where the ambient noise level is low, better sound quality can be obtained in terms of delicacy or frequency characteristics compared to air conduction sound through the ear canal and middle ear. Absent. On the other hand, even in use in an environment where the ambient noise level is high, the S / N ratio is insufficient.

JP 2003-348208 A

  Therefore, a technical problem of the present invention is to provide a speaker device mainly composed of bone conduction that can be used in various environments.

  The present invention focuses not only on improving the frequency characteristics and Q of the piezoelectric vibrator, but also mainly using bone-conducted sound and easily and instantaneously adjusting the sound vibration output during use according to the usage environment. It was made.

  The speaker device of the present invention includes a pressure sensor that detects a pressing force between a piezoelectric vibrating body, a vibration transmitting body that presses the piezoelectric vibrating body, and a vibration output of the piezoelectric vibrating body according to a change in the pressing force. And a vibration output control means for changing.

  The speaker device according to the present invention is characterized in that, in the speaker device, the pressure sensor is configured to have high sensitivity to static pressure and low sensitivity in an audio frequency band.

  Furthermore, the speaker device of the present invention is characterized in that, in the speaker device, the piezoelectric vibrating body is supported by a support, and the pressure sensor is attached to the support.

  The speaker device of the present invention uses a pressure sensor that detects a pressing force between a vibration transmitting body that presses the piezoelectric vibrating body and transmits the vibration output, and the vibration output of the piezoelectric vibrating body according to the pressing force. Since the output control means for changing the vibration force is provided, the vibration output can be instantaneously changed by changing the pressing force. In particular, when the level of audio information reaching the inner ear is relatively low with respect to the level of external noise caused by air conduction sound, the force for pressing the piezoelectric vibrator against the auricle (ear shell) or head is increased. In addition to an increase in the amount of transmission due to changes in the acoustic physical constants before and after the transmission interface, an increase in vibration output by the piezoelectric vibrator is brought about, and the level of audio information reaching the inner ear can be increased. .

  In the speaker device of the present invention, the pressure sensor has high sensitivity to static pressure and low sensitivity in the audio frequency band. Therefore, the force pressing the piezoelectric vibrator against the auricle or the head is detected as static pressure. However, the vibration output of the piezoelectric vibrating body is detected only slightly. As a result, the vibration output of the piezoelectric body can be adjusted depending only on the pressing force.

  In the speaker device of the present invention, since the piezoelectric vibrating body is supported by the support and the pressure sensor is held by the support, the piezoelectric vibrating body is moved to the auricle or the head by operating the support by hand. The force pressed against the part can be easily adjusted. Further, since the pressure sensor is attached to the support, the pressing force can be accurately detected.

  As a result of providing these means, according to the present invention, it is possible to instantaneously adjust the size of the voice information reaching the auditory organ of the inner ear according to the environment. That is, according to the present invention, it is possible to provide a speaker device mainly composed of bone conduction that can cope with various environments.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing an example of the speaker device of the present invention. Referring to FIG. 1, the speaker device includes a piezoelectric vibration member 11, a pressure sensor 12, a support member 13 that supports the piezoelectric vibration member 11 and the pressure sensor 12, and an arc shape protruding from a part of the support member 13. And an elongated ear hook 14. In FIG. 1, illustrations of codes used for electrical connection are omitted.

  FIG. 2 is a block diagram showing the configuration of the speaker device of the present invention. Referring to FIG. 2, the piezoelectric vibrating body 11 and the pressure sensor 12 are connected to the output control circuit 23, respectively. The output control circuit 23 changes the vibration output of the piezoelectric vibrating body 11 according to the output of the pressure sensor 12.

  3A and 3B are diagrams showing a specific configuration of the piezoelectric vibrating body 11 shown in FIGS. 1 and 2. FIG. 3A is a longitudinal sectional view, and FIG. 3B is an external perspective view. As shown in FIG. 3 (a), the piezoelectric vibrator 11 has piezoelectric ceramic plates 43 formed on both sides of a shim 2 made of a metal elastic plate, and further covered with a coating layer 4 made of a flexible material. It is a configuration. As shown in FIG. 3A, the piezoelectric vibrator 11 is a rectangular plate-shaped piezoelectric bimorph in which the left-right direction of the paper is the longitudinal direction, and in FIG. 3B, the diagonally lower left direction is the longitudinal direction. When one piezoelectric ceramic plate 3 extends in the longitudinal direction, a voltage is applied so that the other piezoelectric ceramic plate 3 contracts in the longitudinal direction, and bimorph vibration is generated. Here, the piezoelectric ceramic plate 3 generates a displacement in the longitudinal direction (displacement in the left-right direction on the paper surface) mainly using a piezoelectric lateral effect.

  The piezoelectric ceramic plate 3 is rectangular and polarized in the thickness direction, and causes expansion and contraction according to electric signals applied to the upper and lower surfaces. In addition, when the electrode is divided into two groups for each layer and the polarization and voltage can be applied for each layer in the configuration in which the layers are stacked in the thickness direction, there is an advantage that the driving voltage can be greatly reduced. In addition, illustration of a voltage application means, electrical connection, etc. is abbreviate | omitted.

  Next, a specific method for manufacturing the piezoelectric vibrating body 11 used in the present invention will be described. First, NEC TOKIN piezoelectric ceramics (trade name Nepec 10) are used for the two piezoelectric ceramic plates 3, and the dimensions are 32 mm in length, 8 mm in width, and 0.15 mm in thickness. The shim 2 is made of brass having a thickness of 50 μm, and its length and width are substantially the same as those of the piezoelectric ceramic plate 3. These were bonded together with an epoxy-based adhesive, and an electrode (not shown) was provided on the outer main surface of the piezoelectric ceramic plate 3, and lead wires were drawn from this electrode and the shim 2.

  Next, liquid urethane rubber was poured into the entire surface of the piezoelectric bimorph using a brass mold, and the coating layer 4 was formed with a thickness of about 1.5 mm on two surfaces in the thickness direction by a curing process. The resonance frequency and the Q of the vibrating body are adjusted by the thickness of the covering layer 4. At this time, if one piezoelectric ceramic plate 3 is formed of a plurality of layers and an electrode is provided for each layer, the driving voltage can be lowered accordingly.

  The description will be continued with reference to FIGS. 1 and 2 again. A semiconductor pressure sensor is used for the pressure sensor 12, and the support 13 and the ear hook 14 are made of urethane rubber, and support an output control circuit 23 for adjusting the vibration output of the piezoelectric vibrator 11 according to the output of the pressure sensor. Embedded in the body 13.

  The operation of the speaker device according to the embodiment of the present invention thus manufactured will be described.

  FIG. 4 is a schematic view showing a usage state of the speaker device of the present invention. Referring to FIG. 4, the ear device 14 of the speaker device 101 is worn over the pinna 32 on the human head 33. Reference numeral 34 is a hand.

  As shown in FIG. 4, the speaker device 101 of the present embodiment is used by being pressed against the auricle 32. Therefore, information transmission by bone conduction through the cartilage of the auricle 32 is mainly performed. However, information transmission by air conduction sound through the air of the external auditory canal is also included.

  First, when the external noise level is low, the elastic force by the ear hook 14 brings a pressing force, and the pressing force is small. On the other hand, when the external noise level becomes high, if the hand 34 is pressed together, the pressure sensor 12 (see FIG. 1) detects an increase in pressure, and the output control circuit (see FIG. 2) 11 (see FIG. 1) is increased. At this time, when the piezoelectric vibrating body 11 is strongly pressed against the auricular cartilage of the auricle 32, the acoustic property constant before and after the interface changes, and the level of the transmitted sound vibration increases.

  Therefore, the level increase due to the change in the physical property constant and the level increase of the vibration output of the piezoelectric vibrating body are added, and the level of the sound vibration reaching the auditory organ of the inner ear increases.

  As the pressure sensor used at this time, a sensor that does not respond to the vibration output of the piezoelectric vibrator 11 is preferable. Therefore, a sensor that detects only the static pressure and is small enough to ignore the sensitivity of the sound frequency band from the piezoelectric vibrator is suitable. However, it is sufficient to use a pressure sensor chip that can detect a static pressure, and it is easy to extract only the DC component by a filter or the like.

  As described above, the speaker device according to the present invention can be applied to a receiver such as a mobile phone, a hearing aid, a headphone of an audio device, and the like.

It is a perspective view which shows the speaker apparatus by embodiment of this invention. It is a block diagram which shows the circuit structure of the speaker apparatus of FIG. FIGS. 1A and 1B show the piezoelectric vibrator of FIGS. 1 and 2, wherein FIG. 1A is a longitudinal sectional view, and FIG. It is the schematic which shows the use condition of the speaker apparatus by embodiment of this invention.

Explanation of symbols

2 Shims 3 Piezoelectric Ceramic Plate 4 Covering Layer 11 Piezoelectric Vibrating Body 12 Pressure Sensor 13 Support 14 Ear Hook 23 Output Control Circuit 32 Auricle 33 Head 34 Hand 101 Speaker Device

Claims (3)

  A pressure sensor that detects a pressing force between the piezoelectric vibrating body and a vibration transmitting body that presses the piezoelectric vibrating body; and a vibration output control unit that changes a vibration output of the piezoelectric vibrating body in accordance with a change in the pressing force. A speaker device comprising:   The speaker device according to claim 1, wherein the pressure sensor is configured to have high sensitivity to static pressure and low sensitivity in an audio frequency band. The speaker device according to claim 1, wherein the piezoelectric vibrating body is supported by a support body, and the pressure sensor is attached to the support body.

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