JP6479104B2 - Sound generator - Google Patents

Description

  The present invention relates to a sound generator that vibrates a contact surface with which a sound generator contacts and generates sound from the contact surface.

  Conventional electronic devices such as mobile phones generate sound from speakers provided in the electronic devices. Dynamic speakers are the mainstream of speakers used in conventional electronic devices. For example, Patent Document 1 discloses a vibration generator having a dynamic speaker structure including a magnet, a voice coil, a diaphragm, and a case for housing them. An apparatus is described.

5-85192

  However, the vibration generating device described in Patent Document 1 has a dynamic speaker structure, and the sound output depends on the size of the diaphragm. Therefore, the smaller the speaker, the smaller the output. Output may not be obtained.

  The objective of this invention made | formed in view of this viewpoint is providing the sound generator which can output a favorable sound according to a condition.

The sound generator according to the present invention that achieves the above object is as follows.
A piezoelectric vibration part having a laminated piezoelectric element that expands and contracts along the lamination direction;
A weight for applying a load to the piezoelectric vibrating portion;
The piezoelectric vibration part is deformed by applying a sound signal to the multilayer piezoelectric element while a load from the weight is applied to the piezoelectric vibration part, and the piezoelectric vibration part expands and contracts along the stacking direction. The contact surface with which the sound generator contacts is vibrated by deformation of the mode to generate sound from the contact surface ,
One end of the piezoelectric vibrating portion in the expansion / contraction direction of the multilayer piezoelectric element is open to the outside of the device .

In addition, the sound generator according to the present invention that achieves the above-described object,
Comprising a piezoelectric vibration part having a laminated piezoelectric element that expands and contracts along the lamination direction;
With the load applied to the piezoelectric vibration part, the piezoelectric vibration part is deformed by applying a sound signal to the multilayer piezoelectric element, and the expansion / contraction mode of the piezoelectric vibration part is deformed along the stacking direction. Vibrating the contact surface with which the sound generator contacts to generate sound from the contact surface ;
One end of the piezoelectric vibrating portion in the expansion / contraction direction of the multilayer piezoelectric element is open to the outside of the device .

With the load applied to the piezoelectric vibration part, the piezoelectric vibration part is deformed by applying a sound signal to the multilayer piezoelectric element, and the expansion / contraction mode of the piezoelectric vibration part is deformed along the stacking direction. A sound may be generated from the mounting surface by vibrating the mounting surface on which the sound generator is mounted.

  According to this invention comprised as mentioned above, the sound generator which can output a favorable sound according to a condition can be provided.

1 is an external perspective view showing a schematic configuration of a sound generator according to an embodiment of the present invention. It is an external appearance perspective view of the principal part which decomposes | disassembles and shows the back surface side of the mobile telephone of FIG. It is a figure which shows the structure of the laminated piezoelectric element of FIG. It is a figure which shows the modification of a lamination type piezoelectric element. It is a partial expanded sectional view of the piezoelectric vibration part of FIG. It is a figure which shows the modification of the stand in the back surface side of a mobile telephone. It is a functional block diagram of the principal part of the mobile telephone of FIG. It is a side view which shows the state mounted on the contact surface using the stand about the mobile phone of FIG. 4 is a flowchart showing an operation procedure of sound output performed by the mobile phone of FIG. 1. It is a figure which shows an example of the frequency characteristic of the filter process by DSP of FIG. It is a figure which shows arrangement | positioning of the piezoelectric vibration part and leg part in the mobile telephone of FIG. It is the schematic for demonstrating operation | movement of the piezoelectric vibration part in the mobile telephone of FIG. 7 is a flowchart showing a modification of the operation procedure of sound output performed by the mobile phone of FIG. 1. It is a figure which shows three modifications of the holding | maintenance form of a piezoelectric vibration part. It is a figure which shows schematic structure of the principal part which shows the modification of a piezoelectric vibration part.

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

  FIG. 1 is an external perspective view of a sound generator according to an embodiment of the present invention. The sound generator according to the present embodiment includes a mobile phone 10 such as a smartphone and a piezoelectric vibration unit 60. As will be described later, the mobile phone 10 functions as a weight (weight of a sound generator) that applies a load to the piezoelectric vibrating portion 60. The sound generator according to the present embodiment includes a piezoelectric vibrator 60 for a sound generator on the lower surface 20a side that is one long side of the main body 20 of the mobile phone 10. The lower surface 20a faces the contact surface when the mobile phone 10 is placed horizontally on a contact surface such as a desk.

  In the main body 20, a panel 30, an input unit 31, a speaker 40, and a microphone 71 are arranged on the front side of the mobile phone 10, and a part of the panel 30 is shown in FIG. In addition, the display unit 50 is held. Moreover, the proximity sensor 72 is arrange | positioned at the main body 20 at the upper surface 20b side located in the reverse side of the lower surface 20a. The speaker 40, the microphone 71, and the proximity sensor 72 are detection mechanisms that constitute a detection unit that detects two states in the mobile phone 10. Two states detected by the detection unit and specific detection methods thereof will be described later. A battery pack, a camera unit, and the like are mounted on the back side of the main body 20 and are covered with a battery lid 21.

  The panel 30 includes a touch panel that detects contact, a cover panel that protects the display unit 50, and the like, and is formed of, for example, glass or a synthetic resin such as acrylic. The panel 30 has a rectangular shape, for example. The panel 30 may be a flat plate or a curved panel whose surface is smoothly inclined. When panel 30 is a touch panel, it detects contact of a user's finger, pen, stylus pen, or the like. As a detection method of the touch panel, any method such as a capacitance method, a resistance film method, a surface acoustic wave method (or an ultrasonic method), an infrared method, an electromagnetic induction method, and a load detection method can be used. In the present embodiment, for convenience of explanation, panel 30 is a touch panel.

  The input unit 31 receives an operation input from a user, and includes, for example, an operation button (operation key). The panel 30 can also accept an operation input from the user by detecting a user's contact with a soft key or the like displayed on the display unit 50.

  The display unit 50 is a display device such as a liquid crystal display, an organic EL display, or an inorganic EL display.

  The speaker 40 is a sound output device such as a dynamic speaker or a capacitor speaker, and outputs sound based on a sound signal applied from a control unit included in the mobile phone 10.

  The microphone 71 detects the user's voice during a call, and detects the sound generated from the contact surface during the sound generation by the piezoelectric vibration unit 60. Further, the proximity sensor 72 is a sensor that detects the presence of the detection target in a non-contact manner, and can be, for example, a camera, an infrared sensor, a sound wave sensor, or the like.

  FIG. 2 is a schematic perspective view of an essential part of the cellular phone 10 of FIG. On the back side of the main body 20, a battery pack 80, a camera unit 81, and the like are mounted. In addition, the mobile phone 10 includes in the main body 20 an inclination detection sensor 73 that detects an inclination of a piezoelectric element described later of the piezoelectric vibration unit 60, a vibration detection sensor 74 that detects vibration applied to the mobile phone 10, and wireless And a communication unit 75. The inclination detection sensor 73 and the vibration detection sensor 74 are detection mechanisms that constitute a detection unit that detects two states, and are configured by, for example, an acceleration sensor. The wireless communication unit 75 has a known communication function as the mobile phone 10 and acquires position information by a GPS (Global Positioning System) function, or a WiFi (Wireless Fidelity) access point. By acquiring connection information, it is possible to acquire information related to the position of the mobile phone 10.

  The cellular phone 10 includes a holding unit 100 that houses and holds the piezoelectric vibrating unit 60 on the back side of the main body 20. The holding unit 100 includes a slit 101 that extends along the short direction of the main body 20 and has a uniform width that opens to the lower surface 20a.

  The piezoelectric vibration unit 60 includes a piezoelectric element 61, an O-ring 62, and an insulating cap 63 that is a covering member. A piezoelectric element is an element that expands or contracts or bends according to an electromechanical coupling coefficient of a constituent material by applying an electric signal (voltage). These elements are made of, for example, ceramic or quartz. The piezoelectric element may be a unimorph, bimorph or multilayer piezoelectric element. The multilayer piezoelectric element includes a multilayer bimorph element in which bimorphs are laminated (for example, about 8 to 40 layers), a plurality of dielectric layers made of, for example, PZT (lead zirconate titanate), and the plurality of dielectric layers. There is a stack type composed of a laminated structure with electrode layers arranged between body layers. A unimorph expands and contracts when an electric signal is applied, a bimorph bends when an electric signal is applied, and a stack type stacked piezoelectric element expands and contracts along the stacking direction when an electric signal is applied.

  In the present embodiment, the piezoelectric element 61 is formed of a stack type stacked piezoelectric element. The laminated piezoelectric element 61 includes, for example, a dielectric 61a made of ceramics such as PZT and an internal electrode having a comb-like cross section, as shown in the enlarged cross-sectional view and plan view in FIGS. 61b are alternately stacked. The internal electrode 61b is formed by alternately stacking the one connected to the first side electrode 61c and the one connected to the second side electrode 61d, and electrically connecting the first side electrode 61c or the second side electrode 61d, respectively. Connected to.

  The laminated piezoelectric element 61 shown in FIGS. 3A and 3B has, on one end face, a first lead connection portion 61e electrically connected to the first side surface electrode 61c and a second side surface electrode 61d. An electrically connected second lead connecting portion 61f is formed. A first lead wire 61g and a second lead wire 61h are connected to the first lead connecting portion 61e and the second lead connecting portion 61f, respectively. In addition, the first side electrode 61c, the second side electrode 61d, the first lead connection portion 61e, and the second lead connection portion 61f are connected to the first lead connection portion 61e and the second lead connection portion 61f, respectively. 61g and the second lead wire 61h are connected and covered with an insulating layer 61i.

  The stacked piezoelectric element 61 has a length in the stacking direction of, for example, 5 mm to 120 mm. Moreover, the cross-sectional shape in the direction orthogonal to the stacking direction of the multilayer piezoelectric element 61 can be, for example, a substantially square shape of 2 mm square to 10 mm square or an arbitrary shape other than the square shape. Note that the number of laminated piezoelectric elements 61 and the cross-sectional area of the laminated piezoelectric element 61 depend on the weight of the mobile phone 10 serving as a weight (for example, 80 g to 800 g in the case of a portable electronic device). It is determined appropriately so that the sound pressure or sound quality of the sound generated from the contact surface 150 can be sufficiently secured.

  As will be described later with reference to FIG. 7, the laminated piezoelectric element 61 is supplied with a sound signal (reproduced sound signal) from the control unit 130 via a DSP (digital signal processor) 120. In other words, a voltage corresponding to the sound signal is applied to the multilayer piezoelectric element 61 from the control unit 130 via the DSP 120. When the voltage applied from the control unit 130 is an AC voltage, when a positive voltage is applied to the first side electrode 61c, a negative voltage is applied to the second side electrode 61d. Conversely, when a negative voltage is applied to the first side electrode 61c, a positive voltage is applied to the second side electrode 61d. When a voltage is applied to the first side electrode 61c and the second side electrode 61d, polarization occurs in the dielectric 61a, and the stacked piezoelectric element 61 expands and contracts from a state where no voltage is applied. The direction of expansion and contraction of the stacked piezoelectric element 61 is substantially along the stacking direction of the dielectric 61a and the internal electrode 61b. Alternatively, the expansion / contraction direction of the multilayer piezoelectric element 61 substantially coincides with the lamination direction of the dielectric 61a and the internal electrode 61b. Since the laminated piezoelectric element 61 expands and contracts substantially along the stacking direction, there is an advantage that the vibration transmission efficiency in the stretching direction is good.

  3A and 3B, the first side electrode 61c and the second side electrode 61d are alternately connected to the internal electrode 61b, and are connected to the first lead connection portion 61e and the second lead connection portion 61f. It can also be a through-hole connected to each other. 3 (a) and 3 (b), the first lead connecting portion 61e and the second lead connecting portion 61f are formed of a first side electrode 61c and a first side electrode 61c at one end of the multilayer piezoelectric element 61, as shown in FIG. You may form in the 2nd side electrode 61d.

  As shown in the partial enlarged cross-sectional view of FIG. 5, the laminated piezoelectric element 61 has one end side surface including the first lead connection portion 61 e and the second lead connection portion 61 f bonded to the slit 101 of the holding portion 100 of the main body 20. It fixes through the agent 102 (for example, epoxy resin). Further, a cap 63 is inserted into the other end portion of the multilayer piezoelectric element 61 and is fixed by the adhesive 102.

  The cap 63 is formed of a material that can reliably transmit the expansion and contraction vibration caused by the stacked piezoelectric element 61 to the contact surface 150 such as a desk, for example, hard plastic. When it is desired to suppress damage to the contact surface 150, the cap 63 may be a relatively soft plastic instead of a hard plastic. The cap 63 is formed with an entry portion 63 a located in the slit 101 and a projection 63 b protruding from the main body 20 in a state of being attached to the multilayer piezoelectric element 61, and the entry located in the slit 101. An O-ring 62 is disposed on the outer periphery of the portion 63a. The O-ring 62 is made of, for example, silicone rubber. The O-ring 62 is used to move and hold the multilayer piezoelectric element 61 and at the same time makes it difficult for moisture or dust to enter the slit 101. The protrusion 63b has a hemispherical tip. Note that the tip of the protrusion 63b is not limited to a hemispherical shape, but may be any shape as long as it can reliably make point contact or surface contact with the contact surface 150 of a desk or the like to transmit the expansion and contraction vibration by the stacked piezoelectric element 61. It can be a shape. In FIG. 5, the gap between the O-ring 62 and the adhesion portion of the multilayer piezoelectric element 61 to the slit 101 can be filled with gel or the like to further enhance the dustproof and waterproof effect. The piezoelectric vibrating portion 60 is attached to the holding portion 100, and the protruding portion 63 b of the cap 63 protrudes from the lower surface 20 a of the main body 20 in a state where the battery lid 21 is attached to the main body 20. Further, the protruding portion 63 b of the cap 63 has a facing surface 63 c that is a surface facing the lower surface 20 a of the main body 20. As shown in FIG. 5, the opposing surface 63c is separated from the lower surface 20a by a length d in a state where no voltage is applied to the multilayer piezoelectric element 61 and the multilayer piezoelectric element 61 does not expand or contract.

  Referring to FIG. 2 again, the mobile phone 10 includes a stand 90 that can be opened and closed on the battery lid 21, that is, the main body 20. The stand 90 includes a leg portion 91 and an attachment portion 92 that serves as a fulcrum during opening and closing. In the present embodiment, the stand 90 has a mounting portion 92 on the upper surface 20b side opposite to the lower surface 20a of the main body 20 in the state of being housed in the main body 20, and the lower surface 20a along the short direction of the main body 20. It has a leg 91 extending to the side. The main body 20 of the mobile phone 10 is provided with a space 82 for storing a stand 90 provided in the battery lid 21. When the cellular phone 10 is placed on a horizontal contact surface 150 such as a desk with the lower surface 20a side down, that is, when the cellular phone 10 is laid sideways, at least the legs 91 and the piezoelectric vibration unit 60 is supported in contact with the contact surface 150. The stand 90 is preferably provided so that the inclination angle of the panel 30 can be adjusted when the mobile phone 10 is laid sideways.

  Further, the stand 90 is not limited to the above-described form. For example, as shown in FIG. 6A, the stand 90 has a mounting portion 92 on the lower surface 20 a side of the main body 20 in the storage state in the main body 20, and the upper surface 20 b side along the short direction of the main body 20. The leg portion 91 may be configured to extend in the direction. Further, for example, as shown in FIG. 6B, the stand 90 has a mounting portion 92 on one side of the main body 20 in the storage state in the main body 20, and the other side along the longitudinal direction of the main body 20. The leg portion 91 may be configured to extend on the side surface side. The mobile phone 10 may include a plurality of stands 90 as shown in FIG. 6C, for example.

  FIG. 7 is a functional block diagram of the main part of the mobile phone 10. The mobile phone 10 includes the panel 30, the input unit 31, the speaker 40, the display unit 50, the laminated piezoelectric element 61, the microphone 71, the proximity sensor 72, the tilt detection sensor 73, the vibration detection sensor 74, and the wireless communication unit 75 described above. In addition, a DSP 120 and a control unit 130 are provided. The microphone 71, the proximity sensor 72, the tilt detection sensor 73, the vibration detection sensor 74, and the wireless communication unit 75 are examples of detection mechanisms that constitute the detection unit 70. Note that the detection unit 70 does not necessarily include all the five detection mechanisms illustrated in FIG. 7, and may include at least one detection mechanism. The panel 30, the input unit 31, the display unit 50, and the detection mechanisms 71 to 75 are connected to the control unit 130. In addition, the speaker 40 and the multilayer piezoelectric element 61 are connected to the control unit 130 via the DSP 120. The DSP 120 may be built in the control unit 130.

  The control unit 130 is a processor that controls the overall operation of the mobile phone 10. The control unit 130 reproduces a sound signal to be applied to the speaker 40 or the laminated piezoelectric element 61 via the DSP 120 in accordance with the two states detected by the detection unit 70 (speech of the other party or music including a ringtone or music) The voltage corresponding to the reproduced sound signal is controlled. The reproduced sound signal may be based on music data stored in an internal memory, or music data stored in an external server or the like may be reproduced via a network.

  Here, detection of two states performed by the detection unit 70 using each detection mechanism will be described. The detection unit 70 uses one of the detection mechanisms to detect two states, a drive permission state in which the drive of the piezoelectric element 61 is permitted and a drive rejection state in which the drive of the piezoelectric element 61 is refused.

  First, the case where the microphone 71 is used as the detection mechanism will be described. When the mobile phone 10 is used while being placed on, for example, a futon or the like, the vibration of the piezoelectric element 61 is absorbed by the soft futon that is the contact surface 150. Therefore, it is difficult to obtain good sound from the contact surface 150. Therefore, when the sound is generated by driving the piezoelectric element 61, the contact surface 150 of the mobile phone 10 placed in a horizontal position is a hard material that generates a sound volume equal to or higher than a predetermined set value. It is preferable. Further, when the contact surface 150 is soft, it is preferable to generate sound from the speaker 40 instead of driving the piezoelectric element 61. Therefore, it is preferable that the control unit 130 controls the application of the sound signal to the piezoelectric element 61 or the speaker 40 according to the volume of the sound generated from the contact surface 150.

  Therefore, first, the microphone 71 acquires the sound generated from the contact surface 150, and the detection unit 70 determines whether the drive permission state and the drive rejection state are based on whether the volume of the acquired sound is equal to or higher than a set value. To detect. The control unit 130 controls the application of the sound signal to the piezoelectric element 61 or the speaker 40 according to the state detected by the detection unit 70. Specifically, before outputting the sound to be reproduced by the user of the mobile phone 10, the control unit 130 first applies a pure tone sweep signal of a certain level as a sound signal to the piezoelectric element 61, A sound is generated from the contact surface 150 by vibrating. And the sound which the contact surface 150 generate | occur | produces is acquired with the microphone 71, and when the volume of the acquired sound is more than a setting value, the detection part 70 detects that it is a drive permission state. On the other hand, when the volume of the acquired sound is less than the set value, the detection unit 70 detects that the drive is rejected. The set value of the volume used for detecting the state can be set to an arbitrary value, for example, 40 db. The pure tone sweep signal may be a signal in a frequency range that is difficult to be heard by human ears.

  When the detection unit 70 detects the drive permission state, the control unit 130 applies a sound signal to the piezoelectric element 61. On the other hand, when the detection unit 70 detects the drive refusal state, the control unit 130 does not apply the sound signal to the piezoelectric element 61 or applies the sound signal when the sound signal has already been applied. Stop. When the sound signal is not applied to the piezoelectric element 61, the control unit 130 may apply the sound signal to the speaker 40. The operation of the control unit after the detection unit 70 detects the drive permission state or the drive rejection state is the same for other detection mechanisms described later.

  The detection of the two states using the microphone 71 may be performed only once before the sound signal is applied, or is continuously performed while the sound signal is being applied to the piezoelectric element 61. It may be a thing. Further, when the movement of the mobile phone 10 is detected by a vibration detection sensor 74 described later, the state using the microphone 71 may be detected. When the detection unit 70 continues to detect the state while applying the sound signal to the piezoelectric element 61, the detection unit 70 is generated from the contact surface 150 by the application of the sound signal to the piezoelectric element 61. The sound may be acquired from the microphone 71, and the state may be detected based on whether the volume of the acquired sound is equal to or higher than a set value. This detection may be performed continuously or periodically or irregularly. In addition, when the state is detected based on the sound generated from the contact surface 150 by the sound signal applied to the piezoelectric element 61, the set value of the volume used for detecting the two states is a pure tone sweep signal. Therefore, it can be different from the set value when the state is detected. For example, when the user has set a large volume output from the mobile phone 10, the set value of the volume used for detecting the state can be increased.

  The microphone 71 may acquire ambient noise in addition to the sound generated from the contact surface 150. In order to prevent erroneous detection of a state due to the influence of noise, the mobile phone 10 acquires ambient sounds from the microphone 71 when the output of the sound signal from the control unit 130 is low or there is no output, and the mobile phone 10 When the state is detected by storing in a storage unit (not shown), the state may be detected after performing processing for canceling the sound corresponding to the stored noise from the sound acquired from the microphone 71. .

  Next, a case where the proximity sensor 72 is used as a detection mechanism will be described. For example, even when the user is listening to the sound generated from the contact surface 150 by applying a sound signal to the piezoelectric element 61, the user may temporarily leave the mobile phone 10. In that case, since the user who wants to listen to the sound is not around the mobile phone 10, it is not necessary to generate the sound. Therefore, it is advantageous if the sound can be automatically stopped when the user leaves the mobile phone 10. That is, it is preferable that the control unit 130 controls the application of the sound signal to the piezoelectric element 61 or the speaker 40 according to whether or not there is a person around.

  Therefore, the proximity sensor 72 acquires information regarding whether or not there is a person in the surroundings, and the detection unit 70 detects a drive permission state and a drive rejection state based on the acquired information, and performs control according to the detected state. The unit 130 controls application of a sound signal to the piezoelectric element 61 or the speaker 40. Specifically, when the proximity sensor 72 is in a state in which it is confirmed that there is a detection target around the mobile phone 10, the detection unit 70 detects that the drive is allowed, and the proximity sensor 72 When the detection object is not confirmed to be present around the mobile phone 10, the detection unit 70 detects that the drive is rejected. That is, when the proximity sensor 72 confirms that the detection target object is a person around the mobile phone 10, the detection unit 70 detects that the drive is permitted. Apply sound signal. On the other hand, when the proximity sensor 72 confirms that there is no person around the mobile phone 10, the detection unit 70 can detect that the drive is rejected and can stop applying the sound signal to the piezoelectric element 61.

  The proximity sensor 72 may always check the presence or absence of a detection object around the mobile phone 10, and may check regularly or irregularly. Further, in the above-described example, when the proximity sensor 72 confirms the presence of the detection target, the detection unit 70 confirms the drive allowable state, and when the proximity sensor 72 does not confirm the presence of the detection target, the detection unit Although it has been described that 70 confirms the drive rejection state, the detection unit 70 may be configured to reverse the detection of the drive permission state and the drive rejection state. That is, when the proximity sensor 72 has not confirmed the presence of the detection target, the detection unit 70 may confirm the drive allowable state, and the control unit 130 may apply the sound signal to the piezoelectric element 61. On the contrary, when the proximity sensor 72 confirms the presence of the detection target, the detection unit 70 may confirm the drive rejection state, and the control unit 130 may stop applying the sound signal to the piezoelectric element 61.

  Next, the case where the tilt detection sensor 73 is used as the detection mechanism will be described with reference to FIG. FIG. 8 shows a state where the mobile phone 10 is placed on a horizontal contact surface 150 such as a desk using the stand 90. As shown in FIG. 8, the mobile phone 10 is supported on the contact surface 150 by the piezoelectric vibrating portion 60 and the stand 90 (leg portion 91). The mobile phone 10 has a lowermost end 201. The lowermost end portion 201 assumes that the piezoelectric vibrating portion 60 does not exist when the mobile phone 10 of the mobile phone 10 is placed on the horizontal contact surface 150 such as a desk with the lower surface 20a down. In this case, the contact surface 150 is in contact with the contact surface 150. The lowermost end 201 of the mobile phone 10 is, for example, a corner of the main body 20, but is not limited thereto. When the lower surface 20 a is provided with a protruding portion that protrudes from the lower surface 20 a, the protruding portion may be the lowest end portion 201 of the mobile phone 10. The protrusion is, for example, a side key or a connector cap.

As shown in FIG. 8A, when the mobile phone 10 is placed horizontally, the angle θ (inclination θ) formed by the piezoelectric element 61 with respect to the vertical direction is less than a predetermined angle θ ₀ (FIG. 8). In the case of θ ₁ in 8 (a), a sufficient load is applied to the piezoelectric vibrating portion 60 from the mobile phone 10 as a weight. Thereby, the piezoelectric vibration part 60 can vibrate the contact surface 150 appropriately, and a good sound is generated from the contact surface 150. On the other hand, as shown in FIG. 8B, when the angle θ (inclination θ) formed by the piezoelectric element 61 with respect to the vertical direction is equal to or larger than a predetermined angle θ ₀ (in the case of θ ₂ in FIG. 8B). In this case, a sufficient load is not applied from the mobile phone 10 to the piezoelectric vibrating portion 60. As a result, it is difficult for good sound to be generated from the contact surface 150. Further, when the angle of the piezoelectric element 61 is θ ₂ , as compared with the case where the angle of the piezoelectric element 61 is θ ₁ , as a reaction of the force that the piezoelectric element 61 vibrates and applies to the contact surface 150, the cellular phone 10 The force of the horizontal component received by the main body 20 increases. For this reason, the mobile phone 10 may slide and move. When the mobile phone 10 moves, if the mobile phone 10 is placed on a desk or the like, for example, the mobile phone 10 may drop from the desk, and the mobile phone 10 or the piezoelectric vibration unit 60 may break down due to the impact of the drop. There is. Further, when the angle θ ₂ is large and the lowermost end portion 201 comes into contact with the contact surface 150, abnormal noise may be generated between the lowermost end portion 201 and the contact surface 150 when the piezoelectric element 61 vibrates. Therefore, it is preferable to control application of a sound signal to the piezoelectric element 61 or the speaker 40 in accordance with the inclination θ of the piezoelectric element 61.

Therefore, the inclination detection sensor 73 detects the inclination of the piezoelectric element 61, and the detection unit 70 detects the drive permission state and the drive rejection state based on the inclination θ of the piezoelectric element 61. The control unit 130 controls the application of the sound signal to the piezoelectric element 61 or the speaker 40 according to the state detected by the detection unit 70. Specifically, when the inclination θ of the piezoelectric element 61 is less than a predetermined angle θ ₀ , the detection unit 70 detects that the drive is permitted. On the other hand, when the inclination θ of the piezoelectric element 61 is equal to or larger than the predetermined angle θ ₀ , the detection unit 70 detects that the drive is rejected. The predetermined angle θ ₀ can be determined as appropriate based on, for example, the size of the mobile phone 10 and the piezoelectric vibration unit 60, the weight of the mobile phone 10, the length and arrangement of the stand 90, and for example, 30 degrees. It can be.

  Next, the case where the vibration detection sensor 74 is used as a detection mechanism will be described. When the mobile phone 10 is used while being placed on, for example, a futon or the like, the vibration of the piezoelectric element 61 is absorbed by the soft futon that is the contact surface 150. Therefore, it is difficult to obtain good sound from the contact surface 150. Accordingly, when the sound is generated by driving the piezoelectric element 61, the contact surface 150 of the mobile phone 10 set up horizontally is a hard material that can sufficiently transmit the vibration of the piezoelectric element 61. It is preferable. Further, when the contact surface 150 is soft, it is preferable to generate sound from the speaker 40 instead of driving the piezoelectric element 61. Therefore, it is preferable that the control unit 130 controls the application of the sound signal to the piezoelectric element 61 or the speaker 40 depending on whether or not the contact surface 150 is a hard material. Here, when the piezoelectric element 61 is driven to generate sound from the contact surface 150, if the contact surface 150 is sufficiently hard, the mobile phone 10 reacts as a reaction of the force that the piezoelectric element 61 vibrates and applies to the contact surface 150. And vibrate with an amplitude corresponding to the vibration of the piezoelectric element 61. That is, when the vibration detection sensor 74 detects the vibration of the mobile phone 10, it can be determined whether or not the contact surface 150 is a hard material.

  Therefore, the vibration detection sensor 74 detects the vibration of the mobile phone 10, and the detection unit 70 detects the drive permission state and the drive rejection state based on the vibration of the mobile phone 10. The control unit 130 controls the application of the sound signal to the piezoelectric element 61 or the speaker 40 according to the state detected by the detection unit 70. Specifically, the vibration detection sensor 74 acquires a vibration waveform of the mobile phone 10. When the contact surface 150 is sufficiently hard and does not absorb the vibration of the piezoelectric element 61, the mobile phone 10 vibrates with the same amplitude as that of the vibration of the piezoelectric element 61, but the material of the contact surface 150 is sufficiently hard. If not, the amplitude of the mobile phone 10 is also reduced by the amount of vibration of the piezoelectric element 61 absorbed according to the material. Accordingly, the detection unit 70 detects two states depending on whether the ratio of the vibration amplitude of the mobile phone 10 to the vibration amplitude of the piezoelectric element 61 is equal to or greater than a predetermined ratio. When the ratio of the amplitude of the mobile phone 10 to the amplitude of the piezoelectric element 61 is equal to or greater than a predetermined ratio, the detection unit 70 detects the drive permission state, and when the ratio is less than the predetermined ratio, the detection unit 70 indicates the drive rejection state. To detect. This predetermined ratio can be arbitrarily determined, for example, 50%. When the predetermined ratio is 50%, for example, assuming that the extension amount (amplitude) of the piezoelectric element 61 is 10 μm, the detection unit 70 detects the drive allowable state when the amplitude of the mobile phone 10 is 5 μm or more. When it is less than 5 μm, the detection unit 70 detects a drive rejection state.

  By using the vibration detection sensor 74, not only the amplitude of vibration that the mobile phone 10 receives as a reaction of the vibration of the piezoelectric element 61 can be detected, but also the movement of the mobile phone 10 can be detected. The movement of the mobile phone 10 is detected by the vibration detection sensor 74 detecting the vibration frequency of the mobile phone 10. For example, it is assumed that the vibration detection sensor 74 detects a vibration having a frequency of 1 to 2 kHz that is a vibration frequency when a human walks. In this case, the detection unit 70 recognizes that the mobile phone 10 is moving and is not placed on the contact surface 150, and detects a drive rejection state. When the vibration detection sensor 74 does not detect the vibration having such a frequency, the detection unit 70 can detect the drive allowable state.

  Next, a case where the wireless communication unit 75 is used as a detection mechanism will be described. Here, it is assumed that the wireless communication unit 75 acquires position information by the GPS function as information regarding the position of the mobile phone 10. When sound is generated using the mobile phone 10, there are places that are not suitable for generating sound, such as public facilities such as a library. In such a place, it is advantageous if the mobile phone 10 can automatically stop the sound. That is, it is preferable that the control unit 130 controls the application of the sound signal to the piezoelectric element 61 or the speaker 40 according to the location where the mobile phone 10 is located.

  Therefore, the wireless communication unit 75 acquires position information using the GPS function, and the detection unit 70 detects the drive permission state and the drive rejection state based on the position information, and the control unit according to the detected state. 130 controls the application of a sound signal to the piezoelectric element 61 or the speaker 40. Specifically, for example, a user registers in advance in the detection unit 70 a place where it is inappropriate to output sound from the mobile phone 10. When the detection unit 70 confirms that the mobile phone 10 is in a previously registered position based on the position information acquired by the wireless communication unit 75, the detection unit 70 detects a drive rejection state. In this case, the control unit 130 can stop the application of the sound signal. On the other hand, when the detection unit 70 confirms that the mobile phone 10 is not in a pre-registered position, the detection unit 70 detects a drive allowable state. In this case, the control unit 130 can apply a sound signal.

  In the above-described example, it has been described that a place where it is inappropriate to output sound from the mobile phone 10 is registered in the detection unit 70 in advance. You may register with the detection part 70 previously. For example, a private location of a user such as a home is registered in the detection unit 70 in advance. When the detection unit 70 confirms that the mobile phone 10 is in a pre-registered position based on the position information acquired by the wireless communication unit 75, the detection unit 70 detects a drive permission state. In this case, the control unit 130 can apply a sound signal. On the other hand, when the detection unit 70 confirms that the mobile phone 10 is not in a previously registered position, the detection unit 70 detects a drive rejection state. In this case, the control unit 130 can stop the application of the sound signal.

  The mobile phone 10 outputs sound based on the operations of the detection unit 70 and the control unit 130 described above. FIG. 9 is a flowchart showing an operation procedure of sound output performed by the mobile phone 10.

  First, in the mobile phone 10, any detection mechanism of the detection unit 70 acquires information for determining two states (step S101). The information for determining the two states is, for example, a sound generated from the contact surface 150 when the detection mechanism is the microphone 71, and the detection target exists around when the detection mechanism is the proximity sensor 72. Whether or not. Subsequently, the detection unit 70 detects whether the mobile phone 10 is in the drive-permitted state or the drive-rejected state based on the information acquired by the detection mechanism (step S102).

  When the detection unit 70 detects the drive permission state (the drive permission state in step S102), the control unit 130 determines application of the sound signal to the piezoelectric element 61 (step S103). Then, the control unit 130 applies a sound signal to the piezoelectric element 61 (step S106). On the other hand, when the detection unit 70 detects the drive rejection state (the drive rejection state in step S102), the control unit 130 determines whether or not to drive the speaker 40 (step S104).

  For example, when the proximity sensor 72 detects that there is no person around, and the detection unit 70 detects a drive refusal state, the mobile phone 10 does not need to output sound from the speaker 40. In such a case, the control unit 130 can determine that the speaker is not driven. Further, for example, when the wireless communication unit 75 detects that the mobile phone 10 is in a library and the detection unit 70 detects a drive refusal state, the wireless communication unit 75 outputs a sound from the speaker 40 of the mobile phone 10. Is not appropriate. In such a case, the control unit 130 can determine that the speaker is not driven. As described above, whether or not the control unit 130 drives the speaker 40 can be determined based on information of each detection mechanism. However, the determination of the control unit 130 is not limited to this, and may be performed by providing different determination criteria and algorithms.

  When it is determined that the control unit 130 drives the speaker 40 (Yes in Step S104), the control unit 130 determines application of the sound signal to the speaker 40 (Step S105). And the control part 130 applies a sound signal to the speaker 40 (step S106). On the other hand, when the control unit 130 determines not to drive the speaker 40 (No in step S104), the control unit 130 ends this flow without applying the sound signal. When the detection unit 70 detects two states regularly or irregularly, the mobile phone 10 may repeat this flow.

  When the mobile phone 10 repeats this flow and the sound output destination is switched by switching the application destination of the sound signal between the piezoelectric element 61 and the speaker 40, the mobile phone 10 switches the sound output destination. This may be notified to the user. The notification to the user can be performed by various methods. For example, the output destination of the sound may be displayed on the display unit 50 of the mobile phone 10. For example, when the output destination of a sound is switched, a notification sound indicating that the output destination has been switched may be inserted into the output sound.

  For example, when the detection unit 70 detects a drive refusal state, the mobile phone 10 may notify the user that the drive refusal state is present. The notification of the drive refusal state can be performed by various methods. For example, it is displayed on the display unit 50 of the mobile phone, or a separate LED (Light Emitting Diode) is provided on the mobile phone 10. This can be done by turning on the LED.

  Referring again to FIG. 7, the DSP 120 performs necessary signal processing such as equalizing processing, D / A conversion processing, boosting processing, and filtering processing on the digital signal from the control unit 130, and the speaker 40 and the piezoelectric element. A required sound signal is applied to 61.

  The maximum voltage of the reproduced sound signal applied to the multilayer piezoelectric element 61 can be, for example, 10 Vpp to 50 Vpp, but is not limited to this range, and depends on the weight of the mobile phone 10 and the performance of the multilayer piezoelectric element 61. It can be adjusted as appropriate. Further, the sound signal applied to the laminated piezoelectric element 61 may be biased with a DC voltage, and a maximum voltage may be set around the bias voltage.

  Further, not only the laminated piezoelectric element 61, the piezoelectric element generally has a larger power loss at higher frequencies. Therefore, the filter processing of the sound signal to the laminated piezoelectric element 61 by the DSP 120 has a frequency characteristic that attenuates or cuts at least a part of a frequency component of about 10 kHz to 50 kHz, or the attenuation rate increases gradually or stepwise. It is set to have frequency characteristics. FIG. 10 shows frequency characteristics when the cutoff frequency is about 20 kHz as an example. Thus, power consumption can be suppressed by attenuating or cutting high frequency components.

  Next, the arrangement of the piezoelectric vibrating portion 60 and the leg portion 91 will be described with reference to FIG. FIG. 11 shows a state where the mobile phone 10 is placed on a horizontal contact surface 150 such as a desk with the lower surface 20a facing downward. Here, the desk is an example of a contacted member, and the contact surface 150 is an example of a contact surface on which the sound generator is placed. As shown in FIG. 11, the mobile phone 10 is supported such that at least the leg portion 91 and the piezoelectric vibrating portion 60 are in contact with each other on the contact surface 150. A point G is the center of gravity of the mobile phone 10. That is, point G is the center of gravity of the sound generator weight.

  In FIG. 11, the leg portion 91 has a lowermost end portion 911. The lowermost end portion 911 is a portion of the leg portion 91 that comes into contact with the contact surface 150 when the mobile phone 10 is placed on a horizontal contact surface 150 such as a desk with the lower surface 20a facing downward.

  The piezoelectric vibration part 60 has a lowermost end part 601. The lowermost end portion 601 is a portion of the piezoelectric vibrating portion 60 that comes into contact with the contact surface 150 when the mobile phone 10 is placed on a horizontal contact surface 150 such as a desk with the lower surface 20a facing down. The lowermost end 601 is, for example, the tip of the cap 63.

  In FIG. 11, a dotted line L is a line that passes through the center of gravity G of the mobile phone 10 and is perpendicular to the contact surface 150 when the mobile phone 10 is placed on a horizontal contact surface 150 such as a desk with the lower surface 20 a facing down. (Virtual line). An alternate long and short dash line I is a line (virtual line) connecting the lowermost end 911 of the leg 91 and the lowermost end 201 of the mobile phone 10 when it is assumed that the piezoelectric vibrating part 60 does not exist. The dotted line L1 is a line (virtual line) that passes through the lowermost end 601 and is perpendicular to the contact surface 150. The dotted line L2 is a line (imaginary line) that passes through the lowermost end portion 911 and is perpendicular to the contact surface 150. The dotted line L1 is separated from the dotted line L by a length D1 in the horizontal direction. The dotted line L2 is separated from the dotted line L by a length D2 in the horizontal direction.

  In FIG. 11, a region R <b> 2 is a region on one side delimited by a dotted line L in the mobile phone 10. The region R1 is a region on the other side delimited by the dotted line L in the mobile phone 10. The leg portion 91 is provided on the region R2 side. Further, the piezoelectric vibrating portion 60 is provided on the region R1 side on the lower surface 20a.

  The piezoelectric vibrating portion 60 is preferably provided at a position as close as possible to the dotted line L on the region R1 side. Thereby, the load in the vertical direction applied to the piezoelectric vibrating portion 60 becomes larger than when the piezoelectric vibrating portion 60 is provided at a position separated from the dotted line L on the region R1 side. Thereby, the mobile phone 10 can be effectively used as the weight of the sound generator.

  The lowermost end 911 of the leg 91 is preferably provided at a position as far as possible from the dotted line L on the region R2 side. Thereby, even when the piezoelectric vibrating portion 60 is provided at a position as close as possible to the dotted line L, a sufficient distance between the lowermost end portion 911 and the piezoelectric vibrating portion 60 is ensured, and the sound generator can be stably stabilized. It can be mounted on.

  The lowest end portion 601 of the piezoelectric vibrating portion 60 is a one-dot chain line I when a voltage is not applied to the laminated piezoelectric element 61 and the laminated piezoelectric element 61 extends most from a state where it does not expand or contract or when the laminated piezoelectric element 61 has a maximum amplitude. It is better to be located closer to the contact surface 150 side. That is, the lowermost end portion 601 is in contact with the multi-layered piezoelectric element 61 more than the one-dot chain line I when the multi-layered piezoelectric element 61 is extended to the maximum from the state where it does not expand or contract or when the multi-layered piezoelectric element 61 has the maximum amplitude. It is good to protrude to the surface 150 side. Thereby, the contact surface 150 can be appropriately vibrated by the piezoelectric vibrating portion 60.

  The lowermost end 601 of the piezoelectric vibration unit 60 is applied when the laminated piezoelectric element 61 is contracted most from the state in which no voltage is applied to the laminated piezoelectric element 61 and the laminated piezoelectric element 61 does not expand or contract, or the laminated piezoelectric element 61. When the minimum amplitude is, it is preferable to be located closer to the contact surface 150 than the alternate long and short dash line I. That is, the lowest end portion 601 is one point at the time when the multilayer piezoelectric element 61 is at the minimum amplitude when the multilayer piezoelectric element 61 contracts the most from the state in which the voltage is not applied to the multilayer piezoelectric element 61 and the multilayer piezoelectric element 61 does not expand and contract. It is preferable that the contact surface 150 protrudes from the chain line I. Thereby, the lowermost end portion 201 of the mobile phone 10 is less likely to come into contact with the contact surface 150. For example, depending on the type of coating of the main body 20, the coating is less likely to be peeled off. Further, abnormal noise is less likely to occur between the lowermost end 201 and the contact surface 150.

  FIGS. 12A, 12B, and 12C are schematic diagrams for explaining the operation of the mobile phone 10 as a sound generator. When the mobile phone 10 functions as a sound generator, the mobile phone 10 has a cap 63 and a leg portion 91 of the piezoelectric vibrating portion 60 with the lower surface 20a side of the main body 20 facing downward, as shown in FIG. It is placed sideways so as to contact the contact surface 150 such as a desk. Thereby, the weight of the mobile phone 10 is given to the piezoelectric vibrating portion 60 as a load. That is, the mobile phone 10 functions as a weight of the sound generator according to the present invention. In the state shown in FIG. 12A, the stacked piezoelectric element 61 does not expand and contract because no voltage is applied.

  In this state, when the multilayer piezoelectric element 61 of the piezoelectric vibration unit 60 is driven by the reproduction sound signal, the multilayer piezoelectric element 61 is brought into contact with the leg 91 as shown in FIGS. With the contact portion with the surface 150 as a fulcrum, the cap 63 expands and contracts according to the reproduced sound signal without being separated from the contact surface 150. If there is no inconvenience such as abnormal noise being generated when the lowermost end portion 201 contacts the contact surface 150, the lower end portion 201 may be slightly separated. The difference between the length of the laminated piezoelectric element 61 when it is most expanded and the length when it is most contracted is, for example, 0.05 μm to 50 μm. As a result, the expansion and contraction vibration of the multilayer piezoelectric element 61 is transmitted to the contact surface 150 through the cap 63 and the contact surface 150 vibrates, and the contact surface 150 functions as a vibration speaker to generate sound from the contact surface 150. If the difference between the length when stretched most and the length when shrunk most is less than 0.05 μm, the contact surface may not be vibrated properly. On the other hand, if it exceeds 50 μm, the vibration will increase. There is a risk that the sound generator will rattle.

  Here, as described above, when it is assumed that the piezoelectric vibrating portion 60 does not exist when the multilayer piezoelectric element 61 is extended to the end of the cap 63, the cap 63 and the lowermost end portion 911 of the leg portion 91 are portable. It is good to be located on the contact surface 150 side with respect to the line (one-dot chain line I in FIG. 11) connecting the lowermost end portion 201 of the telephone 10. The tip of the cap 63 is preferably located closer to the contact surface 150 than the virtual line when the multilayer piezoelectric element 61 is contracted most.

  Further, the distance d between the lower surface 20a and the facing surface 63c of the cap 63 shown in FIG. 5 is a state where the voltage is not applied to the multilayer piezoelectric element 61 and the multilayer piezoelectric element 61 is contracted most from the state where the multilayer piezoelectric element 61 does not expand and contract. It is better to be longer than the amount of displacement when Thereby, even when the laminated piezoelectric element 61 is in the most contracted state (the state shown in FIG. 12C), the lower surface 20a of the main body 20 and the cap 63 can be hardly contacted. Therefore, it becomes difficult for the cap 63 to fall off the piezoelectric element 61.

  The arrangement location on the lower surface 20a of the piezoelectric vibrating section 60, the length of the stacked piezoelectric element 61 in the stacking direction, the size of the cap 63, and the like are appropriately determined so as to satisfy the above-described conditions.

  The sound generator according to the present embodiment can output a good sound depending on the situation. Specifically, the mobile phone 10 can output a sound using a piezoelectric element when the detection unit 70 detects a drive allowable state. As this piezoelectric element, a stack-type laminated piezoelectric element 61 is used to cause expansion / contraction vibration along the lamination direction by a reproduced sound signal, and the expansion / contraction vibration is transmitted to the contact surface 150. Direction) and the contact surface 150 can be efficiently vibrated. In addition, since the multilayer piezoelectric element 61 is brought into contact with the contact surface 150 via the cap 63, the multilayer piezoelectric element 61 can be prevented from being damaged. Further, when the mobile phone 10 is placed sideways and the cap 63 of the piezoelectric vibration unit 60 is brought into contact with the contact surface 150, the weight of the mobile phone 10 is applied to the cap 63 as a load. The expansion and contraction vibration of the piezoelectric vibration part 60 can be efficiently transmitted to the contact surface 150. As described above, when the detection unit 70 detects the drive allowable state, a good sound can be generated using the piezoelectric element.

  In addition, according to the sound generator according to the present embodiment, the detection unit 70 detects the two states of the piezoelectric element 61 that are allowed to drive and the drive rejected state using each detection mechanism, and the detected state. In response to this, a sound signal is applied to the piezoelectric element 61 or the speaker 40. Therefore, for example, in situations where it is not necessary to generate sound from the piezoelectric element 61 or situations where it is inappropriate to generate sound from the piezoelectric element 61, application of the sound signal to the piezoelectric element 61 is stopped, or instead A sound signal can be applied to the speaker 40. Thus, the sound generator according to the present embodiment can apply a sound signal according to the situation and output a sound.

  In addition, this invention is not limited only to the said embodiment, Many deformation | transformation or a change is possible. For example, in the above embodiment, the detection unit 70 has been described as detecting two states using any one of the detection mechanisms, but the present invention is not limited to this form. That is, the detection unit 70 may detect two states using two or more detection mechanisms. When the detection unit 70 detects two states using two or more detection mechanisms, the detection unit 70 detects the drive allowable state in all the detection mechanisms used to detect the two states. 130 can execute the application of a sound signal to the piezoelectric element 61. On the other hand, when the detection unit 70 detects the drive rejection state in any of the detection mechanisms used to detect the two states, the control unit 130 can stop the application of the sound signal to the piezoelectric element 61. . At this time, the control unit 130 may apply a sound signal to the speaker 40.

  Here, the case where the detection unit 70 detects two states using two detection mechanisms will be specifically described. Here, the case where the microphone 71 is used as the first detection mechanism and the proximity sensor 72 is used as the second detection mechanism will be described, but the present invention is not limited to this, and the first and second detection mechanisms are not limited thereto. Any detection mechanism can be used as the mechanism. FIG. 13 is a flowchart illustrating an operation procedure of sound output performed by the mobile phone 10 when the detection unit 70 detects two states using two detection mechanisms.

  First, in the mobile phone 10, the microphone 71 as the first detection mechanism acquires information for determining two states, that is, the sound generated from the contact surface 150 (step S201). Next, the detection unit 70 detects whether the mobile phone 10 is in a drive-permitted state or a drive-rejected state based on the information acquired by the first detection mechanism (step S202). When the detection unit 70 detects the drive permission state (drive permission state in step S202), the proximity sensor 72 as the second detection mechanism has information for determining the two states, that is, the detection target exists in the surroundings. Information regarding whether or not to do so is acquired (step S203). Then, the detection unit 70 detects whether the mobile phone 10 is in the drive-permitted state or the drive-rejected state based on the information acquired by the second detection mechanism (step S204). When the detection unit 70 detects a drive permission state (drive permission state in step S204), the control unit 130 determines application of a sound signal to the piezoelectric element 61 (step S205). And the control part 130 applies a sound signal to the piezoelectric element 61 (step S208).

  On the other hand, when the detection unit 70 detects the drive refusal state based on the information acquired by one of the first and second detection mechanisms (the drive refusal state in step S202 or the drive refusal state in step S204), the control unit 130 determines whether to drive the speaker 40 (step S206). For example, the control unit 130 determines to drive the speaker 40 when the detection unit 70 detects a drive rejection state based on information acquired by the microphone 71 of the first detection mechanism, and the proximity sensor of the second detection mechanism. It can be determined that the speaker 40 is not driven when the detection unit 70 detects the drive refusal state based on the information acquired by 72.

  When it is determined that the control unit 130 drives the speaker 40 (Yes in step S206), the control unit 130 determines application of the sound signal to the speaker 40 (step S207). And the control part 130 applies a sound signal to the speaker 40 (step S208). On the other hand, when the control unit 130 determines not to drive the speaker 40 (No in step S206), the control unit 130 does not apply the sound signal and ends this flow. When the detection unit 70 detects two states regularly or irregularly, the mobile phone 10 may repeat this flow. In addition, even when the detection unit 70 detects two states using three or more detection mechanisms, the mobile phone 10 can output sound in the same operation procedure.

  As described above, the detection unit 70 detects two states, that is, the drive permission state and the drive rejection state of the piezoelectric element 61 using two or more detection mechanisms, and the control unit 130 responds to the detected state. By applying a sound signal to the piezoelectric element 61 or the speaker 40, it is possible to apply a sound signal according to a plurality of different situations and output a sound.

  Moreover, in the said embodiment, the structure which fixes the piezoelectric vibration part 60 with respect to the holding | maintenance part 100 is not restricted to what is shown in FIG. As shown in FIGS. 14A to 14C, the piezoelectric vibrating unit 60 may be held by the holding unit 100. The holding unit 100 shown in FIG. 14A includes a wide slit 101a that opens to the lower surface 20a, and a narrow slit 101b that continues to the slit 101a. The laminated piezoelectric element 61 has one end portion arranged in the narrow slit 101 b and the side surface fixed to the slit 101 b via the adhesive 102. Further, the wide slit 101 a is filled with a filler 103 such as silicone rubber or gel that does not hinder the expansion and contraction operation of the multilayer piezoelectric element 61 in the gap with the multilayer piezoelectric element 61. If the piezoelectric vibrating portion 60 is held by the holding portion 100 in this manner, the cellular phone 10 can be waterproofed more reliably without using a waterproof packing such as an O-ring. Further, by covering the portion projecting from the lower surface 20a of the multilayer piezoelectric element 61 with an insulating cap, the multilayer piezoelectric element 61 can be reliably insulated.

  The holding unit 100 shown in FIG. 14B includes a tapered slit 101c that expands toward the lower surface 20a, and a narrow slit 101d that continues to the tapered slit 101c. The laminated piezoelectric element 61 has one end portion disposed in the narrow slit 101 d and the side surface fixed to the slit 101 d via the adhesive 102. The tapered slit 101 c is filled with a filler 103 such as silicone rubber or gel that does not hinder the expansion and contraction operation of the multilayer piezoelectric element 61 in the gap with the multilayer piezoelectric element 61. With this configuration, the same effect as that of the holding unit 100 of FIG. 14A can be obtained, and since the tapered slit 101c is provided, the multilayer piezoelectric element 61 can be easily assembled to the holding unit 100. There are advantages that can be made.

  The holding unit 100 shown in FIG. 14C has a slit 101 having a uniform width as in the above embodiment, but the laminated piezoelectric element 61 has an end face on one end side through an adhesive 102. It is fixed to the slit 101. Further, an O-ring 62 is disposed at an appropriate position of the multilayer piezoelectric element 61 in the slit 101. Such a holding mode of the laminated piezoelectric element 61 is particularly suitable when the laminated piezoelectric element 61 has a lead wire connecting portion formed on a side electrode as shown in FIG. Etc. are advantageous.

  Further, in the above embodiment and the modified examples of FIGS. 14A to 14C, the piezoelectric vibrating portion 60 omits the cap 63, and the tip surface of the multilayer piezoelectric element 61 is formed directly or made of an insulating member or the like. You may mount on the contact surface 150 via a vibration transmission member. In addition, the piezoelectric element is not limited to the stack type stacked piezoelectric element described above, and a unimorph, bimorph, or stacked bimorph element may be used. FIG. 15 is a diagram showing a schematic configuration of a main part when a bimorph is used. The bimorph 65 has a long rectangular shape, one surface 65 a is exposed on the lower surface 20 a of the main body 20, and both long ends are held by the holding unit 100. The holding unit 100 has an opening 101e that holds the bimorph 65, and the inner surface of the opening 101e on the back surface 65b side of the bimorph 65 is curved. According to this configuration, when the main body 20 is placed on the contact surface 150 so that the bimorph 65 contacts the contact surface 150 and the bimorph 65 is driven by the reproduction sound signal, the bimorph 65 bends (curves) and vibrates. As a result, the vibration of the bimorph 65 is transmitted to the contact surface 150, and the contact surface 150 functions as a vibration speaker, and a reproduction sound is generated from the contact surface 150. Note that a coating layer such as polyurethane may be formed on the surface 65 a of the bimorph 65.

  In the above embodiment, the detection mechanism is not limited to the microphone 71, the proximity sensor 72, the tilt detection sensor 73, the vibration detection sensor 74, and the wireless communication unit 75. The detection mechanism may be any detection mechanism as long as the detection unit 70 is used for detecting two states.

  For example, a camera is provided on the lower surface 20a of the main body 20, and the detection unit 70 can use this camera as a detection mechanism. The camera periodically or irregularly captures an image of the lowermost end portion 601 corresponding to the tip portion of the piezoelectric vibration unit 60 and detects whether the piezoelectric vibration unit 60 is in contact with the contact surface 150. The detection unit 70 detects the drive allowable state when confirming that the piezoelectric vibration unit 60 and the contact surface 150 are in contact with each other based on the image captured by the camera, Detects a denial condition. For example, when there is a change in an image captured by the camera, the detection unit 70 may recognize that the mobile phone 10 has moved and detect a drive rejection state. In this way, the cellular phone 10 drives the piezoelectric element 61 when the piezoelectric vibrating portion 60 is in contact with the contact surface, or stops driving the piezoelectric element 61 when the cellular phone 10 is moving. Can be.

  Further, for example, the detection unit 70 can use a clock provided in the mobile phone 10 as a detection mechanism. When using the timepiece as a detection mechanism, the user registers a time zone during which no sound signal is applied to the piezoelectric element 61 in the detection unit 70 in advance. When the clock indicates the time of the pre-registered time zone, the detection unit 70 recognizes that it is a time zone during which no sound signal is applied to the piezoelectric element 61 and detects the drive rejection state. On the other hand, when the timepiece indicates a time other than the pre-registered time zone, the detection unit 70 recognizes that it is a time zone in which a sound signal is applied to the piezoelectric element 61 and detects a drive permission state. When using the timepiece as a detection mechanism, the user may register the time zone in which the sound signal is applied to the piezoelectric element 61 in the detection unit 70 in advance. In this case, when the clock indicates the time of the pre-registered time zone, the detection unit 70 detects the drive permission state, and when the clock indicates a time other than the pre-registered time zone, the detection unit 70 is in the drive rejection state. Is detected. By using the timepiece as a detection mechanism, for example, the piezoelectric element 61 is not used to generate sound at midnight, or the piezoelectric element 61 is used to generate sound only at specific times during the day. Can be.

  In addition, the mobile phone 10 includes a content recognition unit that recognizes content to be played back, and the detection unit 70 can use the content recognition unit as a detection mechanism. The content recognition unit recognizes whether the content to be reproduced is content that may be shared with others other than the user based on a predetermined algorithm, for example. In addition, for example, content that the user may share with others other than the user is registered in advance in the content recognition unit. Then, when outputting sound from the mobile phone 10, the content recognition unit recognizes whether the sound is content that may be shared with others other than the user. When the content recognition unit recognizes that the content may be shared, the detection unit 70 detects the drive permission state, and when the content recognition unit recognizes that the content is not shareable, the detection unit 70 sets the drive rejection state. To detect. The content that may be shared can be, for example, the sound of a movie or a television program. On the other hand, content that does not correspond to content that may be shared can be, for example, a sound that may contain information related to the individual of the user, such as recording of an answering machine. In this way, it is possible to prevent information relating to the user's individual from leaking to others due to sound output using the piezoelectric element 61.

  Further, the mobile phone 10 includes a remaining battery level detection unit that detects the remaining battery level, and the detection unit 70 can use the remaining battery level detection unit as a detection mechanism. When the remaining battery level detection unit detects that the remaining battery level of the mobile phone 10 is greater than or equal to a predetermined value, for example, when detecting that the remaining battery level is 10% or more of the battery capacity, the detection unit 70 Detecting the drive allowable state. On the other hand, when the remaining battery level detecting unit detects that the remaining battery level of the mobile phone 10 is less than a predetermined value, for example, when detecting that the remaining battery level is less than 10% of the battery capacity, 70 detects a drive rejection state. In this way, the mobile phone 10 can stop driving the piezoelectric element 61 or drive the speaker 40 whose battery consumption is smaller than that of the piezoelectric element 61 when the remaining battery level is low.

  Further, the mobile phone 10 includes an operation detection unit, and the detection unit 70 can use the operation detection unit as a detection mechanism. That is, when the operation detection unit recognizes an operation from the user to the mobile phone 10, the detection unit 70 detects the drive rejection state, and when the operation detection unit does not recognize the operation to the mobile phone 10, the detection unit 70 Detects the drive allowable state. In this way, for example, by preventing the piezoelectric element 61 from vibrating while the user is operating the mobile phone 10, it is possible to prevent the user from operating the mobile phone 10. In the detection of the state using the operation detection unit, the detection unit 70 has been described as detecting the drive refusal state regardless of what operation is performed in the above description. However, for a predetermined operation, the detection unit 70 is driven. The mobile phone 10 may be configured to detect the allowable state. For example, when a user performs an operation related to sound, such as volume control operation, it is convenient if sound is output from the mobile phone 10. Therefore, the mobile phone 10 may be configured so that the detection unit 70 detects the drive-permitted state, for example, by registering the predetermined operation in advance in the operation detection unit.

  Further, the detection unit 70 can use the stand 90 as a detection mechanism. For example, when the stand 90 is accommodated in the main body 20, the detection unit 70 can recognize that the sound output using the piezoelectric element 61 is not used and can detect the drive refusal state. On the other hand, when the stand 90 is pulled out from the main body 20, the detection unit 70 recognizes that the sound output using the piezoelectric element 61 is used, and can detect the drive allowable state. As described above, the detection unit 70 can detect two states using various detection mechanisms.

  In the above-described embodiment, the mobile phone 10 is described as including the speaker 40, but the mobile phone 10 may not include the speaker 40. In this case, the mobile phone 10 generates a sound by applying a sound signal to the piezoelectric element 61 when the detecting unit 70 detects the drive allowable state, and generates a sound signal when the drive refusal state is detected. Is not applied and no sound is generated. Thus, when the mobile phone 10 does not include the speaker 40, the number of components can be reduced as compared with a mobile phone having a dynamic speaker structure, and thus the mobile phone 10 can be simply configured with a small number of components. Therefore, the mobile phone 10 can have a smaller configuration.

  Moreover, although said non-contact member was a desk and said contact surface 150 was a horizontal mounting surface of a desk in said embodiment, this invention is not limited to this. The contact surface 150 may not be a horizontal surface. For example, the contact surface 150 may be a surface perpendicular to the desk ground. Examples of the contacted member having a surface perpendicular to the ground include a partition for partitioning a space.

  Moreover, in the said embodiment, although the sound generator was mounted in the mobile telephone 10 and the mobile telephone 10 was functioned as a weight, a weight is not restricted to this. For example, a variety of electronic devices such as portable music players, stationary televisions, telephone conference systems, laptop computers, projectors, wall clocks / wall televisions, alarm clocks, photo frames, etc. can be used as weights to generate sound. A vessel can also be installed.

DESCRIPTION OF SYMBOLS 10 Mobile phone 20 Main body 20a Lower surface 20b Upper surface 21 Battery lid 30 Panel 31 Input part 40 Speaker 50 Display part 60 Piezoelectric vibration part 61 Piezoelectric element 62 O-ring 63 Cap 70 Detection part 71 Microphone 72 Proximity sensor 73 Tilt detection sensor 74 Vibration detection sensor 75 Wireless communication section 80 Battery pack 81 Camera unit 90 Stand 91 Leg section 92 Mounting section 100 Holding section 101 Slit 120 Digital signal processor (DSP)
130 Control part 150 Contact surface

Claims (3)

A sound generator,
A piezoelectric vibration part having a laminated piezoelectric element that expands and contracts along the lamination direction;
A weight for applying a load to the piezoelectric vibrating portion;
The piezoelectric vibration part is deformed by applying a sound signal to the multilayer piezoelectric element while a load from the weight is applied to the piezoelectric vibration part, and the piezoelectric vibration part expands and contracts along the stacking direction. The contact surface with which the sound generator contacts is vibrated by deformation of the mode to generate sound from the contact surface ,
A sound generator in which one end of the piezoelectric vibrating section in the expansion / contraction direction of the multilayer piezoelectric element is open to the outside of the device itself . A sound generator,
Comprising a piezoelectric vibration part having a laminated piezoelectric element that expands and contracts along the lamination direction;
With the load applied to the piezoelectric vibration part, the piezoelectric vibration part is deformed by applying a sound signal to the multilayer piezoelectric element, and the expansion / contraction mode of the piezoelectric vibration part is deformed along the stacking direction. Vibrating the contact surface with which the sound generator contacts to generate sound from the contact surface ;
A sound generator in which one end of the piezoelectric vibrating section in the expansion / contraction direction of the multilayer piezoelectric element is open to the outside of the device itself .   With the load applied to the piezoelectric vibration part, the piezoelectric vibration part is deformed by applying a sound signal to the multilayer piezoelectric element, and the expansion / contraction mode of the piezoelectric vibration part is deformed along the stacking direction. The sound generator according to claim 1 or 2, wherein a sound is generated from the placement surface by vibrating the placement surface on which the sound generator is placed.

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