JP6216126B2 - Electronics - Google Patents

Description

  The present invention relates to an electronic device that generates a vibration sound that is transmitted by vibrating a vibration part by applying a predetermined electrical signal (audio signal) to the piezoelectric element to vibrate a part of a human body.

  Patent Document 1 describes an electronic device such as a mobile phone that transmits air conduction sound and bone conduction sound to a user. According to Patent Document 1, air conduction sound is sound transmitted to the auditory nerve of a user by vibration of air that is caused by vibration of an object being transmitted to the eardrum through the external auditory canal. Have been described. Patent Document 1 describes that the vibration sound is a sound transmitted to the user's auditory nerve through a part of the user's body (for example, the cartilage of the outer ear) that contacts the vibrating object. Yes.

  In the telephone set described in Patent Document 1, it is described that a short plate-like vibrating body made of a piezoelectric element (bimorph) and a flexible material is attached to the outer surface of a housing via an elastic member. Further, in Patent Document 1, when a voltage is applied to the piezoelectric element of the vibrating portion, the piezoelectric material expands and contracts in the longitudinal direction, so that the vibrating body bends and vibrates, and the user brings the vibrating body into contact with the auricle. Thus, it is described that the air conduction sound and the vibration sound are transmitted to the user, and the vibrating body functions as a vibrating portion.

JP 2005-348193 A

  In the electronic device described in Patent Document 1, no consideration has been given to the power consumption of the piezoelectric element attached to the vibrating portion.

  An object of the present invention is to provide an electronic device that takes into account the power consumption of the piezoelectric element in an electronic device that generates a vibration sound by vibrating a vibrating portion with a piezoelectric element.

Electronic device according to one aspect of the present invention includes a vibration unit for generating a vibration sound transmitted by vibrating the parts of the body in contact with or pressed, mounted stacked on the vibrating section, the first piezoelectric element and the first A second piezoelectric element having a capacitance value larger than that of the piezoelectric element , wherein the first signal is input to the first piezoelectric element, and the second signal is input to the second piezoelectric element. The vibration sound is generated in a low frequency band and a high frequency band by the vibration of the piezoelectric element and the second piezoelectric element, and the voltage of the second signal is the first in the low frequency band. The voltage of the second signal is lower than the voltage of the first signal in the high frequency band . In addition, in the electronic device, the voltage of the second signal out of the first signal and the second signal is increased in the low frequency band, and the first signal is increased in the high frequency band. You may provide the control part which controls so that the voltage of a said 2nd signal may be made small among a signal and a said 2nd signal .

The control unit may include an amplifier that variably controls the second signal according to a frequency band .

The first piezoelectric element and the second piezoelectric element may have different shapes. Furthermore, the first piezoelectric element and the second piezoelectric element are preferably in the shape of a rectangular plate, and the length of at least one side of each is preferably different. Alternatively, the first piezoelectric element and the second piezoelectric element may have different thicknesses in the stacking direction. Furthermore, the first piezoelectric element and the second piezoelectric element may be stacked piezoelectric elements, and the number of layers may be different from each other.

  The vibration unit may be a panel. Further, the vibrating part may be larger than the size of the ear.

The vibration unit may include a display unit. The first piezoelectric element and the second piezoelectric element may be attached to a position different from the attachment position of the display unit in the vibration unit.

Even when the vibration part is pressed against a part of the human body to be pressed with a force of 3N or more, the vibration part may vibrate the part and transmit the vibration sound. Furthermore, even if the vibration unit is pressed against a portion of the human body to be pressed with a force of 5N or more, the vibration portion is preferably transmitted by vibrating the portion.
Further, the control unit sets the voltage of the second signal as the first voltage in the middle frequency band, and increases the voltage of the second signal higher than the first voltage in the low frequency band. The second voltage is a third voltage in which the voltage of the second signal is suppressed more than the first voltage in the high frequency band, and the first voltage is changed to the third voltage. The suppression amount may be controlled to be larger than the increase amount from the first voltage to the second voltage.

  According to the embodiments described below, it is possible to provide an electronic device that generates vibration sound by vibrating a vibration unit using a piezoelectric element, in consideration of power consumption of the piezoelectric element.

It is a figure which shows the functional block of an electronic device. It is a figure explaining the frequency characteristic of a piezoelectric element. It is a figure explaining operation | movement of a control part. It is a figure which shows the example of the shape and magnitude | size of a panel. It is a figure which shows the mounting structure of the electronic device which concerns on 1st Embodiment. It is a figure which shows the example of the vibration of the panel in 1st Embodiment. It is a figure which shows the mounting structure of the electronic device which concerns on 2nd Embodiment. It is a figure which shows the example of the vibration of the panel in 2nd Embodiment. It is a figure which shows the example of the support structure of a panel.

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

  FIG. 1 is a diagram showing functional blocks of an electronic device 1 according to an embodiment of the present invention. The electronic device 1 is, for example, a mobile phone (smart phone), and includes a panel 10, a display unit 20, piezoelectric elements 30 and 31, an input unit 40, and a control unit 50.

  The panel 10 is a touch panel that detects contact or a cover panel that protects the display unit 20. Panel 10 is formed of synthetic resin such as glass or acrylic. The shape of the panel 10 may be a plate shape. The panel 10 may be a flat plate or a curved panel whose surface is smoothly inclined. When the panel 10 is a touch panel, the touch of a user's finger, pen, stylus pen, or the like is detected. 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.

  The display unit 20 is a display device such as a liquid crystal display, an organic EL display, or an inorganic EL display. The display unit 20 is provided on the back surface of the panel 10. The display unit 20 is disposed on the back surface of the panel 10. The display unit 20 may be bonded to the panel 10 with a bonding member (for example, an adhesive), or may be spaced apart from the panel 10 and supported by the casing of the electronic device 1.

  The piezoelectric elements 30 and 31 are elements that expand or contract or bend (bend) in accordance with an electromechanical coupling coefficient of a constituent material by applying an electric signal (voltage). For these elements, for example, those made of ceramic or quartz are used. The piezoelectric elements 30 and 31 are, for example, unimorph elements or bimorph elements. A unimorph element expands and contracts when an electric signal (voltage) is applied, and a bimorph element bends when an electric signal (voltage) is applied. Alternatively, the piezoelectric elements 30 and 31 may be stacked piezoelectric elements. The stacked piezoelectric element includes a stacked unimorph element in which unimorphs are stacked (for example, 16 layers or 24 layers), or a stacked bimorph element in which bimorphs are stacked (for example, 16 layers or 24 layers are stacked). The laminated piezoelectric element is composed of a laminated structure of a plurality of dielectric layers made of, for example, PZT (lead zirconate titanate) and electrode layers arranged between the plurality of dielectric layers.

  The piezoelectric elements 30 and 31 have different capacitance values. The piezoelectric elements 30 and 31 have different capacities by having different shapes. For example, when the piezoelectric elements 30 and 31 are rectangular plates, the length and / or thickness (the thickness and the number of layers in the case of a laminated type) of at least one side may be different. Alternatively, the piezoelectric elements 30 and 31 may be made of different materials and have different capacitance values. As will be described in detail later, the input signals to the piezoelectric elements 30 and 31 are controlled according to the frequency band.

  The piezoelectric elements 30 and 31 are disposed on the back surface of the panel 10 (the surface on the inner side of the electronic device 1). The first piezoelectric element 30 is attached to the panel 10 by, for example, a joining member (for example, double-sided tape). The piezoelectric element 30 may be attached to the panel 10 via an intermediate member (for example, a sheet metal). The second piezoelectric element 31 is attached to the first piezoelectric element 30 in a stacked manner. The piezoelectric element 31 is attached to the piezoelectric element 30 by, for example, a joining member (for example, a double-sided tape).

  The input unit 40 receives an operation input from a user, and includes, for example, operation buttons (operation keys). In addition, when the panel 10 is a touch panel, the panel 10 can also accept the operation input from a user by detecting the contact from a user.

  The control unit 50 is a processor that controls the electronic device 1. The control unit 50 applies a predetermined electrical signal (voltage corresponding to the audio signal) to the piezoelectric elements 30 and 31. The voltage applied to the piezoelectric elements 30 and 31 by the control unit 50 is, for example, ± 15 V, which is higher than ± 5 V, which is an applied voltage of a so-called panel speaker for the purpose of conducting sound by air conduction sound instead of vibration sound. It may be. Thereby, even when the user touches or presses (presses) the panel 10 to his / her body with a force of 3N or more (for example, a force of 5N to 10N), sufficient vibration is generated in the panel 10. Then, by vibrating a part of the user's body, that is, the contact part or the pressing part, it is possible to generate a vibration sound through the part. Note that how much applied voltage is used can be appropriately adjusted according to the fixing strength of the panel 10 to the casing or the support member or the performance of the piezoelectric element 30.

  When the control unit 50 applies an electrical signal to the piezoelectric elements 30 and 31, the piezoelectric elements 30 and 31 expand or contract or bend according to the voltage (amplitude) and period of the applied electrical signal. At this time, the panel 10 to which the piezoelectric elements 30 and 31 are attached is deformed according to expansion and contraction or bending of the piezoelectric elements 30 and 31, and the panel 10 vibrates. The panel 10 is bent by expansion / contraction or bending of the piezoelectric elements 30 and 31. The panel 10 is bent directly by the piezoelectric elements 30 and 31. “The panel 10 is directly bent by the piezoelectric element” means that the panel is specified by the inertial force of the piezoelectric actuator configured by arranging the piezoelectric element in the casing as used in a conventional panel speaker. This is different from the phenomenon in which the panel is deformed by exciting this area. “The panel 10 is bent directly by the piezoelectric element” means that expansion or contraction (bending) of the piezoelectric element directly bends the panel via the bonding member or the bonding member and the reinforcing member 80 described later. To do. For this reason, the panel 10 generates air conduction sound and also generates vibration sound through a part of the body when the user contacts a part of the body (for example, cartilage of the outer ear). For example, the control unit 50 can apply an electric signal corresponding to a voice signal related to the voice of the other party to the piezoelectric elements 30 and 31 to generate air conduction sound and vibration sound corresponding to the voice signal. The audio signal may relate to a ringing melody or a music piece including music. Note that the audio signal applied to the electrical signal may be based on music data stored in the internal memory of the electronic device 1, or music data stored in an external server or the like is reproduced via a network. May be.

  Further, the control unit 50 controls the voltage (amplitude) of the electric signal applied to the piezoelectric elements 30 and 31 so as to differ according to the frequency band of the output sound. Specifically, the voltage of the electric signal applied to the larger capacitance value of the piezoelectric elements 30 and 31 is increased in the low band, and the voltage of the electric signal applied to the larger capacitance value is decreased in the high band. Control is performed. As a configuration for such control, the control unit 50 includes, for example, an amplifier that variably controls an electric signal having a larger capacitance value among the piezoelectric elements 30 and 31 according to a band. Alternatively, the control unit 50 may include a DSP (Digital Signal Processor) that controls an electric signal for each of the piezoelectric elements 30 and 31.

  The panel 10 has a rectangular shape, for example, and vibrates not only in the attachment region to which the piezoelectric elements 30 and 31 are attached, but also in a region away from the attachment region. The panel 10 has a plurality of locations that vibrate in a direction intersecting the main surface of the panel 10 in the vibrating region, and the amplitude value of the vibration is increased from positive to negative with time in each of the plurality of locations. Or vice versa. At a certain moment, the panel 10 vibrates in a manner that a portion having a relatively large vibration amplitude and a portion having a relatively small vibration amplitude are randomly distributed over the entire panel 10. That is, vibrations of a plurality of waves are detected over the entire panel 10. Even when the user presses the panel 10 against his / her body with a force of 5N to 10N, for example, the control unit 50 applies the piezoelectric elements 30 and 31 to prevent the above-described vibration of the panel 10 from being attenuated. The applied voltage may be ± 15V. Therefore, the user can hear the sound by bringing his / her ear into contact with a region away from the above-described region where the panel 10 is attached.

  Here, the operation and effect of the control of the control unit 50 as described above will be described with reference to FIG. FIG. 2 shows an example of the sound pressure frequency characteristics of the piezoelectric elements 30 and 31 with the horizontal axis representing the frequency of the output sound and the vertical axis representing the sound pressure. This sound pressure frequency characteristic shows a shape that rises to the right generally according to the frequency, and has a resonance point in the vicinity of 3000 Hz. Therefore, on the relatively high frequency side (for example, a band of 1500 Hz or higher), even if the voltage of the electric signal applied to the piezoelectric elements 30 and 31 is the same, the sound pressure of the generated sound is increased. Therefore, a voltage for obtaining a desired sound pressure is small on the high frequency side. Therefore, on the high frequency side, by reducing the voltage of the electric signal applied to the piezoelectric elements 30 and 31, the current consumed by the piezoelectric element 30 or 31 is suppressed and the power consumption is reduced while ensuring the desired sound pressure. Can be made. Here, since the consumption current increases as the capacitance value of the piezoelectric elements 30 and 31 increases, a larger current can be suppressed by reducing the voltage of the piezoelectric elements 30 and 31 having the larger capacitance value. Power consumption can be reduced efficiently.

  FIG. 3 shows an operation example of the control unit 50. The control unit 50 controls the electrical signal as shown in FIG. 3 when the output audio is less than 700 Hz in the low frequency range, 700 Hz to less than 1500 Hz in the middle frequency range, and 1500 Hz or higher in the high frequency range. For example, the capacitance value of the piezoelectric element 30 is 1 μF, and the capacitance value of the piezoelectric element 31 is 2 μF. The controller 50 applies an electric signal of ± 10 V in the low to high range to the piezoelectric element 30 having the smaller capacitance value, while the piezoelectric element 30 in the middle range is applied to the piezoelectric element 31 having the larger capacitance value. The same electrical signal of ± 10V is applied, but an electrical signal of ± (10−β) V (β is an arbitrary positive number of 10 or less) is applied in the high frequency range. That is, the voltage of the electric signal is suppressed. In this way, the current consumption of the piezoelectric element 31 can be suppressed, and the power consumption of the piezoelectric elements 30 and 31 as a whole can be reduced. Further, the control unit 50 increases the voltage of the electric signal applied to the piezoelectric element 31 in the low frequency range according to the sound pressure frequency characteristic, and the electric power of ± (10 + α) V (α is an arbitrary positive number) A signal may be applied. Here, the power consumption as a whole can be suppressed by controlling the amount of current suppression in the high region to be larger than the amount of increase in current in the low region. Α is an arbitrary positive number, but a voltage that allows application to the piezoelectric elements 30 and 31 (performance of the piezoelectric elements 30 and 31) and a voltage that can be boosted by a power amplifier (not shown). Moreover, it is preferable that the sound pressure of the sound generated by the panel is set based on the extent that the sound pressure reaches the upper limit and does not change.

  FIG. 4 shows an example of the shape and size of the panel 10. The panel 10 may be approximately the same size as the user's ear. The panel 10 may be larger than the user's ear, as shown in FIG. In this case, when the user listens to the sound, the entire ear is easily covered with the panel 10 of the electronic device 1, so that it is difficult for ambient sounds (noise) to enter the ear canal. Panel 10 is an area wider than an area having a length corresponding to the distance from the lower leg of the anti-annulus (lower anti-limb) to the anti-tragus and a width corresponding to the distance from the tragus to the anti-annulus. Should just vibrate. The panel 10 preferably has a length corresponding to the distance between a portion near the upper leg of the ankle ring (upper pair leg) in the ear ring and the earlobe, and a distance between the tragus and a portion near the ear ring in the ear ring. It suffices that a region having a width corresponding to is vibrated.

  Here, the length direction is the longitudinal direction 2a in which the panel 10 extends in this example, and the piezoelectric elements 30 and 31 are disposed closer to one end from the center. The width direction is a direction 2b orthogonal to the longitudinal direction. The region having such a length and width may be a rectangular region, or may be an elliptical shape having the above length as the major axis and the width as the minor axis. The average size of Japanese ears can be found by referring to the Japanese human body size database (1992-1994) created by the Human Life Engineering Research Center (HQL). If the panel 10 is larger than the average size of Japanese ears, the panel 10 is considered to be large enough to cover the entire foreign ear. By having the area | region of the above dimensions and shapes, the panel 10 can cover a user's ear | edge and becomes tolerance with respect to the position shift when it touches on an ear | edge. Such a region includes at least the region from the lower end of the piezoelectric elements 30 and 31 to the midpoint of the longitudinal direction 2a of the panel 10.

  The electronic device 1 can transmit air conduction sound and vibration sound transmitted through a part of the user's body (for example, cartilage of the outer ear) to the user by the vibration of the panel 10. Here, the panel 10 is an example of a vibration part. Therefore, when outputting a sound having a volume equivalent to that of a conventional dynamic receiver, the sound transmitted to the periphery of the electronic device 1 due to the vibration of the air due to the vibration of the panel 10 is less than that of the dynamic receiver. Therefore, it is suitable, for example, when listening to a recorded message on a train.

  In addition, since the electronic device 1 transmits vibration sound due to the vibration of the panel 10, even if the user wears an earphone or a headphone, for example, the user can contact the electronic device 1 with the earphone or the headphone so that the user can Sounds can be heard through headphones and body parts.

  The electronic device 1 transmits sound to the user by the vibration of the panel 10. Therefore, when the electronic device 1 does not include a separate dynamic receiver, it is not necessary to form an opening (sound outlet) for sound transmission in the housing, and the waterproof structure of the electronic device 1 can be simplified. In addition, when the electronic device 1 is provided with a dynamic receiver, the sound emission port is preferably closed by a member that allows gas to pass but not liquid. An example of the member that allows gas to pass but not liquid is Gore-Tex (registered trademark).

(First embodiment)
FIG. 5 is a diagram illustrating a mounting structure of the electronic device 1 according to the first embodiment. 5 (a) is a front view, FIG. 5 (b) is a cross-sectional view taken along line bb in FIG. 5 (a), and FIG. 5 (c) is taken along line cc in FIG. 5 (a). FIG. The electronic device 1 shown in FIG. 5 is a smartphone in which a touch panel, which is a glass plate, is arranged as a panel 10 on the front surface of a housing 60 (for example, a metal or resin case).

  The panel 10 and the input unit 40 are supported by the housing 60, and the display unit 20 and the piezoelectric elements 30 and 31 are attached to the panel 10, respectively. The panel 10, the display part 20, and the piezoelectric element 30 are each substantially rectangular.

  The display unit 20 is disposed approximately at the center in the short direction of the panel 10 and is attached to the panel 10 by the joining member 71. The joining member 71 is an adhesive having a thermosetting property or an ultraviolet curable property, and may be, for example, an optical elastic resin that is a colorless and transparent acrylic ultraviolet curable adhesive. Preferably, the display unit 20 is bonded to the panel 10 on the entire surface in contact with the panel 10. By doing so, the rigidity of the diaphragm 100 in the portion where the display unit 20 is bonded to the panel 10 can be increased.

  The piezoelectric elements 30 and 31 are spaced apart from a longitudinal end of the panel 10 by a predetermined distance, and are arranged in the vicinity of the end so that the longitudinal direction of the piezoelectric elements 30 and 31 is along the short side of the panel 10. Is done. The display unit 20 and the piezoelectric elements 30 and 31 are arranged side by side in a direction parallel to the inner surface of the panel 10.

  The piezoelectric elements 30 and 31 are stacked and attached to the panel 10. For example, the first piezoelectric element 30 is bonded to the panel 10 by the bonding member 70. The second piezoelectric element 31 is stacked and bonded to the first piezoelectric element 30 by the bonding member 70. The joining member 70 is an adhesive having a thermosetting property or an ultraviolet curable property, a double-sided tape, or the like, and may be, for example, an optical elastic resin that is a colorless and transparent acrylic ultraviolet curable adhesive. In addition, by using a double-sided tape having elasticity, when both of the piezoelectric elements 30 and 31 are deformed while ensuring the degree of freedom of deformation of each of the piezoelectric elements 30 and 31, the deformation is caused by the elastic deformation of the joining member. Due to the above, each of the piezoelectric elements 30 and 31 is difficult to peel off from the bonding member. Alternatively, as the joining member 70, an adhesive having thermosetting property or ultraviolet curable property may be used. By doing so, it is possible to bond the piezoelectric element 30 and the panel 10 or between the piezoelectric elements 30 and 31 in such a manner that thermal stress shrinkage hardly occurs. Furthermore, here, the joining member 70 used between the piezoelectric element 30 and the panel 10 and the joining member 70 used between the piezoelectric elements 30 and 31 may be made of different types of materials.

  The piezoelectric elements 30 and 31 are separated from the inner surface of the housing 60 by a predetermined distance. The piezoelectric elements 30 and 31 may be separated from the surface on the inner side of the housing 60 by a predetermined distance even in a stretched or bent state. That is, the distance between the piezoelectric elements 30 and 31 and the inner surface of the housing 60 is preferably larger than the maximum deformation amount of the piezoelectric elements 30 and 31.

  In the first embodiment, the piezoelectric elements 30 and 31 have different capacitance values. For example, at least one of the longitudinal lengths 30L and 31L of the piezoelectric elements 30 and 31, the widths 30W and 31W in the direction intersecting the longitudinal direction, or the thicknesses 30T and 31T in the stacking direction is different. The capacitance values of the elements 30 and 31 can be made different. Further, in the case where the piezoelectric elements 30 and 31 are composed of stacked unimorph or bimorph elements, if the number of layers is the same, the thickness of each layer is different, or if the thickness of each layer is the same, the number of layers is increased. The thicknesses 30T and 31T of the entire element can be made different by making them different, and the capacitance values can be made different by doing so. Alternatively, the piezoelectric elements 30 and 31 may be made of different materials so that the capacitance values are different. And the control part 50 controls the voltage of the electric signal applied to the one where a capacitance value is larger according to a zone | band, and can reduce power consumption, ensuring a desired sound pressure. It should be noted that either the closer piezoelectric element 30 or the farther piezoelectric element 31 in the stacking direction on the panel 10 may have either larger capacitance value.

  FIG. 6 is a diagram illustrating an example of vibration of the panel 10 of the electronic device 1 according to the first embodiment. In the electronic device 1 according to the first embodiment, the display unit 20 is attached to the panel 10. For this reason, the lower part of the panel 10 is less likely to vibrate than the upper part of the panel 10 to which the piezoelectric elements 30 and 31 are attached. Therefore, sound leakage due to vibration of the lower portion of the panel 10 at the lower portion of the panel 10 can be reduced. The upper part of the panel 10 is bent directly by the piezoelectric elements 30 and 31, and the vibration is attenuated at the lower part as compared with the upper part. In the panel 10, the portion directly above the piezoelectric elements 30, 31 protrudes higher than the surroundings in the long side direction of the piezoelectric elements 30, 31.

  In addition, according to the electronic device 1 according to the first embodiment, the panel 10 is deformed due to deformation of the piezoelectric elements 30 and 31 attached to the back surface of the panel 10, and the object is in contact with the deformed panel 10. Air conduction sound and vibration sound can be transmitted to objects. Accordingly, since the air conduction sound and the vibration sound can be transmitted to the user without causing the vibration portion to protrude from the outer surface of the housing 60, the patent document in which a very small vibration body is brought into contact with the human body as compared with the housing. The usability is improved as compared with the electronic device described in 1. Further, since it is not necessary to put the user's ears on the piezoelectric element itself, the piezoelectric element itself is not easily damaged. Further, when the case 60 is deformed instead of the panel 10, the user tends to drop the terminal when generating vibration, whereas when the panel 10 is vibrated, Things are hard to happen.

(Second Embodiment)
FIG. 7 is a diagram illustrating a mounting structure of the electronic device 1 according to the second embodiment. 7 (a) is a front view, FIG. 7 (b) is a cross-sectional view taken along line bb in FIG. 7 (a), and FIG. 7 (c) is taken along line cc in FIG. 7 (a). It is sectional drawing. The electronic device 1 shown in FIG. 7 is a foldable mobile phone in which a cover panel (acrylic plate) that protects the display unit 20 as a panel 10 is arranged on the front surface of the upper housing 60.

  In the second embodiment, a reinforcing member 80 is disposed between the panel 10 and the piezoelectric element 30. The reinforcing member 80 is an elastic member such as rubber or silicon. The reinforcing member 80 may be a metal plate made of, for example, aluminum having a certain degree of elasticity. The reinforcing member 80 may be a resin plate, for example. As resin which forms the resin-made board here, a polyamide-type resin is mentioned, for example. Examples of the polyamide-based resin include Reny (registered trademark), which is made of a crystalline thermoplastic resin obtained from metaxylylenediamine and adipic acid and is rich in strength and elasticity. Such a polyamide-based resin may be a reinforced resin reinforced with glass fiber, metal fiber, carbon fiber, or the like using itself as a base polymer. The strength and elasticity are appropriately adjusted according to the amount of glass fiber, metal fiber, carbon fiber, or the like added to the polyamide-based resin. The reinforced resin as described above is formed, for example, by impregnating a resin into a base material formed by braiding glass fiber, metal fiber, carbon fiber, or the like and curing it. The reinforced resin may be formed by mixing a finely cut fiber piece into a liquid resin and then curing it. The reinforced resin may be a laminate of a base material in which fibers are knitted and a resin layer.

  The piezoelectric elements 30 and 31 are stacked and attached to the panel 10. For example, the second piezoelectric element 31 and the first piezoelectric element 30 are bonded by the bonding member 70, the first piezoelectric element 30 and the reinforcing member 80 are bonded by the bonding member 70, and the reinforcing member 80 and the panel 10 are further bonded. Are bonded by the bonding member 70. The joining member 70 is an adhesive having a thermosetting property or an ultraviolet curable property, a double-sided tape or the like. The piezoelectric elements 30 and 31 are spaced apart from a longitudinal end of the panel 10 by a predetermined distance, and are arranged in the vicinity of the end so that the longitudinal direction of the piezoelectric elements 30 and 31 is along the short side of the panel 10. Is done.

  Also in the second embodiment, the capacitance values of the piezoelectric elements 30 and 31 are made different. And the control part 50 controls the voltage of the electric signal applied to the one where a capacitance value is larger according to a zone | band, and can reduce power consumption, ensuring a desired sound pressure.

  In the second embodiment, the display unit 20 is supported by the housing 60. That is, the electronic device 1 according to the second embodiment has a structure in which the display unit 20 and the support unit 90 that is a part of the housing 60 are bonded by the bonding member 72. The support portion 90 is not limited to a configuration as a part of the housing 60, and can be configured as a member independent of the housing 60 by metal, resin, or the like.

  As described above, according to the electronic device 1 according to the second embodiment, the reinforcing member 80 and the panel 10 are deformed due to the deformation of the piezoelectric elements 30 and 31 attached to the panel 10 via the reinforcing member 80. The air conduction sound and the vibration sound are transmitted to the object in contact with the deformed panel 10. Thereby, the air conduction sound and the vibration sound can be transmitted to the user without placing the vibration body itself on the ear. The piezoelectric elements 30 and 31 are attached to the surface of the panel 10 on the inner side of the housing 60. For this reason, the air conduction sound and the vibration sound can be transmitted to the user without causing the vibrating body to protrude from the outer surface of the housing 60. Further, the panel 10 is deformed to transmit the air conduction sound and the vibration sound not only in the attachment region to which the piezoelectric elements 30 and 31 are attached but also in any part of the panel 10. For this reason, the user can hear the vibration sound by bringing his / her ear into contact with an arbitrary position of the panel 10 in addition to the air conduction sound through the air.

  Further, by arranging the reinforcing member 80 between the piezoelectric element 30 and the panel 10, for example, when an external force is applied to the panel 10, the external force is transmitted to the piezoelectric elements 30 and 31, and the piezoelectric elements 30 and 31 are damaged. The possibility of doing so can be further reduced. Moreover, even if the panel 10 is brought into strong contact with the human body, the vibration of the panel 10 can be hardly attenuated. Further, by disposing the reinforcing member 80 between the piezoelectric element 30 and the panel 10, the resonance frequency of the panel 10 is lowered, and the acoustic characteristics in the low frequency band are improved. Instead of the reinforcing member 80, a plate-like weight may be attached to the piezoelectric element 30 by the joining member 70.

  FIG. 8 is a diagram illustrating an example of vibration of the panel 10 of the electronic device 1 according to the second embodiment. In the electronic device 1 according to the second embodiment, the panel 10 is an acrylic plate having a lower rigidity than the glass plate, and the display unit 20 is not bonded to the back surface of the panel 10. As compared with the electronic apparatus 1 according to the above, the amplitude generated by the piezoelectric element is increased. In addition, the panel 10 vibrates not only in the attachment region to which the piezoelectric element is attached, but also in a region away from the attachment region. For this reason, the user can hear the vibration sound by bringing his / her ear into contact with an arbitrary position of the panel 10 in addition to the air conduction sound through the air.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, the functions included in each member can be rearranged so as not to be logically contradictory, and a plurality of components can be combined into one or divided.

  For example, as shown in a cross-sectional view of the housing 60 shown in FIG. 9, the panel 10 may be bonded to the housing 60 with a bonding member 73. Thus, by making it difficult for the vibration from the panel 10 to be directly transmitted to the housing 60, it is possible to reduce the possibility that the user drops the electronic device 1 as compared with the case where the housing itself vibrates greatly. Further, the joining member 73 can be a non-heating type curable adhesive. Accordingly, there is an advantage that thermal stress shrinkage hardly occurs between the housing 60 and the panel 10 at the time of curing. Further, the joining member 73 can be a double-sided tape. Thereby, there exists an advantage that the shrinkage stress like the time of use of an adhesive agent does not generate | occur | produce between the housing | casing 60 and the panel 10 easily.

  For example, when the panel 10 and the display unit 20 are configured not to overlap each other, the piezoelectric elements 30 and 31 may be disposed in the center of the panel 10. When the piezoelectric elements 30 and 31 are disposed in the center of the panel 10, vibrations of the piezoelectric elements 30 and 31 are evenly transmitted to the entire panel 10 to improve the quality of the air conduction sound, or the user listens to the panel 10 The vibration sound can be recognized even if it is brought into contact with various positions.

  In the first and second embodiments described above, the piezoelectric elements 30 and 31 are shown as examples. However, the number of piezoelectric elements may be three or more. In this case, the piezoelectric element that is the target for controlling the electric signal may be a piezoelectric element having the largest capacitance value, or may be a plurality of piezoelectric elements having a larger capacitance value.

  Further, instead of the panel 10, the piezoelectric element is attached to any one of the display panel, the operation panel, the cover panel, and the lid panel for allowing the rechargeable battery to be removed, thereby vibrating the member to which the piezoelectric element is attached. Can act as a part. In particular, when the panel 10 is a display panel, the piezoelectric elements 30 and 31 are disposed outside the display area for the display function. As a result, there is an advantage that the display is hardly disturbed. The operation panel includes the touch panel of the first embodiment. In addition, the operation panel includes a sheet key that is a member that constitutes one surface of the operation unit side body, which is integrally formed with a key top of an operation key in a folding mobile phone, for example.

  In addition, the kind of joining members 70-73 used by 1st Embodiment and 2nd Embodiment can be suitably used according to the member which is the object to adhere | attach.

DESCRIPTION OF SYMBOLS 1 Electronic device 10 Panel 20 Display part 30, 31 Piezoelectric element 40 Input part 50 Control part 60 Case 70-73 Joining member 80 Reinforcement member 90 Support part

Claims (14)

A vibration unit that generates vibration sound transmitted by vibrating a part of a human body that is in contact with or pressed against;
A first piezoelectric element and a second piezoelectric element having a capacitance value larger than that of the first piezoelectric element, which are stacked and attached to the vibration unit;
A first signal is input to the first piezoelectric element, and a second signal is input to the second piezoelectric element;
The vibration sound is generated in a low frequency band and a high frequency band by the vibration of the first piezoelectric element and the second piezoelectric element,
In the low frequency band, the voltage of the second signal is higher than the voltage of the first signal, and in the high frequency band, the voltage of the second signal is smaller than the voltage of the first signal. , Electronics.   In claim 1,
  In the low frequency band, the voltage of the second signal is increased among the first signal and the second signal, and in the high frequency band, the first signal and the second signal are increased. An electronic apparatus having a control unit that controls to reduce the voltage of the second signal among signals.   In claim 2,
  The said control part is an electronic device provided with the amplifier which variably controls the said 2nd signal according to a frequency band. In any one of Claims 1 thru | or 3,
The electronic device in which the first piezoelectric element and the second piezoelectric element have different shapes. In claim 4,
The electronic device, wherein the first piezoelectric element and the second piezoelectric element have a rectangular plate shape, and each has a length of at least one side different. In claim 4 or 5,
The electronic device in which the first piezoelectric element and the second piezoelectric element have different thicknesses in the stacking direction. In claim 6,
The first piezoelectric element and the second piezoelectric element are stacked piezoelectric elements, and each has a different number of layers. In any one of Claims 1 thru | or 7,
The vibration unit is an electronic device that is a panel. In claim 8,
The vibration unit is an electronic device larger than the size of an ear. In claim 8 or 9,
The vibration unit is an electronic device having a display unit. In claim 10,
The electronic device in which the first piezoelectric element and the second piezoelectric element are attached to a position different from an attachment position of the display unit in the vibration unit. In any one of Claims 1 thru | or 11,
The electronic device transmits the vibration sound by vibrating the part even when the vibration part is pressed against the part of the human body to be pressed with a force of 3N or more. In any one of Claims 1 to 12,
The electronic device transmits the vibration sound by vibrating the part even when the vibration part is pressed against the part of the human body to be pressed with a force of 5N or more.   In claim 2 or 3,
  The controller is
    In the middle frequency band, the voltage of the second signal is the first voltage, and in the low frequency band, the voltage of the second signal is the second voltage increased from the first voltage, In the high frequency band, the voltage of the second signal is a third voltage suppressed more than the first voltage,
    An electronic device that controls an amount of suppression from the first voltage to the third voltage to be larger than an amount of increase from the first voltage to the second voltage.

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