JP2012216899A - Audio output device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an audio output device that maximizes sound pressure of an audible sound at a desired distance from a sound hole.SOLUTION: An audio output device 100 has: an oscillation device 70 that has a piezoelectric vibrator 10; a speaker control section (that includes, for example, a control section 50) that inputs modulating signals for a parametric speaker to the oscillation device 70; a sound hole 20 through which ultrasonic sound waves output from the piezoelectric vibrator 10 are emitted; a liquid container 31 that is arranged in the sound hole 20; an acquisition section (for example, an operation-display section 40) that acquires information indicating a desired distance; and a liquid amount adjusting section (that includes, for example, a liquid tank 33, a liquid passage 34, an actuator 32, and the control section 50) that adjusts an amount of liquid filled in the liquid container 31 in accordance with the information acquired by the acquisition section.

Description

  The present invention relates to an audio output device.

A parametric speaker modulates an ultrasonic carrier wave with an audible sound signal using a method such as AM / FM, and radiates it while maintaining high directivity as it is in the air. It demodulates the listening sound. Therefore, the sound pressure of the audible sound to be demodulated becomes maximum at a certain distance from the sound hole of the parametric speaker, but the distance is fixedly determined by the modulation method, the modulation degree, the ultrasonic carrier sound pressure, etc. .
The parametric speaker is described in Patent Documents 1 to 3, for example.

  Patent Document 4 includes a cooling mechanism that is disposed on the back surface of the ultrasonic transducer array and includes a porous member, and a flow path that circulates a liquid heat transfer material through the cooling mechanism. An ultrasonic probe for cooling an ultrasonic transducer while matching acoustic impedance by a mechanism is described.

JP 2005-39439 A JP 2007-228402 A JP 2008-131055 A JP 2008-86362 A

  As described above, in the parametric speaker, the sound pressure of the audible sound demodulated at a certain distance from the sound hole is maximized. For this reason, a technique capable of maximizing the sound pressure of audible sound at a desired distance from the sound hole is demanded.

  An object of the present invention is to provide an audio output device capable of maximizing the sound pressure of an audible sound at a desired distance from a sound hole.

The present invention includes an oscillation device having a piezoelectric vibrator;
A speaker control unit for inputting a modulation signal for a parametric speaker to the oscillation device;
A sound hole for emitting ultrasonic waves output from the piezoelectric vibrator;
A liquid container disposed in the sound hole;
An acquisition unit for acquiring information indicating a target distance;
A liquid amount adjusting unit that adjusts a filling amount of the liquid in the liquid container according to the information acquired by the acquiring unit;
An audio output device is provided.

  According to the present invention, the sound pressure of audible sound can be maximized at a desired distance from the sound hole.

It is principal part sectional drawing of the audio | voice output apparatus which concerns on embodiment. It is sectional drawing which shows the structure of the periphery of a piezoelectric vibrator. It is a block diagram of the audio | voice output apparatus which concerns on embodiment. It is a figure which shows the relationship between the liquid quantity of a liquid container, and the distance from which the sound pressure of an audible sound becomes the maximum. It is a flowchart which shows the flow of operation | movement of the audio | voice output apparatus which concerns on embodiment. It is a figure which shows the example of the operation screen of the audio | voice output apparatus which concerns on embodiment. It is a figure which shows the example of the operation screen of the audio | voice output apparatus which concerns on embodiment. It is a figure which shows the example of the operation screen of the audio | voice output apparatus which concerns on embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

[First Embodiment]
1 is a cross-sectional view of a main part of an audio output device 100 according to the embodiment, FIG. 2 is a cross-sectional view showing a structure around a piezoelectric vibrator 10, FIG. 3 is a block diagram of the audio output device 100, and FIG. FIG. 5 is a flowchart showing the operation flow of the audio output device 100, and FIGS. 6 to 8 are diagrams showing the relationship between the amount of liquid and the distance at which the sound pressure of the audible sound is maximum (distance from the sound hole 20). It is a figure which shows the example of the operation screen of the audio | voice output apparatus.

  The audio output device 100 according to the present embodiment includes an oscillation device 70 having a piezoelectric vibrator 10 and a speaker control unit (for example, configured by the control unit 50) that inputs a modulation signal for a parametric speaker to the oscillation device 70. The sound hole 20 that emits ultrasonic waves output from the piezoelectric vibrator 10, the liquid container 31 disposed in the sound hole 20, and an acquisition unit that acquires information indicating the target distance (for example, the operation unit and display unit 40) ) And a liquid amount adjusting unit (for example, a liquid tank 33, a liquid channel 34, an actuator 32, and a control unit 50) that adjusts the filling amount of the liquid in the liquid container 31 according to the information acquired by the acquiring unit. And). Here, the parametric speaker (ultrasonic speaker) includes a speaker control unit and the piezoelectric vibrator 10. The audio output device 100 is, for example, an electronic device such as a mobile phone or other mobile communication terminal device, a mobile phone or other mobile information terminal device, a laptop personal computer, or a small game device. Details will be described below.

As shown in FIG. 1, the audio output device 100 includes a first housing 1 that houses an oscillation device 70 (FIG. 2) including a piezoelectric vibrator 10 and a second housing 2 that covers the periphery of the first housing 1. And have.
A first opening 1 a that communicates the inside and the outside of the first housing 1 is formed at a position facing the piezoelectric vibrator 10 in the first housing 1.
A second opening 2 a that communicates the inside and outside of the second housing 2 is formed at a position facing the first opening 1 a in the second housing 2.
The sound hole 20 includes first and second openings 1a and 2a.

  As shown in FIG. 2, the oscillation device 70 includes a sheet-like vibration member 71, the piezoelectric vibrator 10, and a support portion 72. The piezoelectric vibrator 10 is attached to one surface of the vibration member 71. The support part 72 supports the edge of the vibration member 71.

  The vibration member 71 vibrates due to vibration generated from the piezoelectric vibrator 10 and oscillates a sound wave having a frequency of 20 kHz or more, for example. The piezoelectric vibrator 10 also oscillates, for example, a sound wave having a frequency of 20 kHz or more when vibrated. The vibration member 71 adjusts the basic resonance frequency of the piezoelectric vibrator 10. The fundamental resonance frequency of the mechanical vibrator depends on the load weight and compliance. Since the compliance is the mechanical rigidity of the piezoelectric vibrator 10, the basic resonance frequency of the piezoelectric vibrator 10 can be controlled by controlling the rigidity of the vibration member 71. The thickness of the vibrating member 71 is preferably 5 μm or more and 500 μm or less. The vibration member 71 preferably has a longitudinal elastic modulus, which is an index indicating rigidity, of 1 GPa or more and 500 GPa or less. If the rigidity of the vibration member 71 is too low or too high, there is a possibility that the characteristics and reliability of the mechanical vibrator are impaired. The material constituting the vibration member 71 is not particularly limited as long as it is a material having a high elastic modulus with respect to the piezoelectric vibrator 10 which is a brittle material such as metal or resin, but phosphor bronze from the viewpoint of workability and cost Or stainless steel is preferred.

  The planar shape of the piezoelectric vibrator 10 is, for example, a circle, but the planar shape of the piezoelectric vibrator 10 is not limited to a circle. For example, the entire surface of the piezoelectric vibrator 10 facing the vibration member 71 is fixed to the vibration member 71 with an adhesive. Thereby, the entire surface of one surface of the piezoelectric vibrator 10 is restrained by the vibration member 71.

  The support part 72 is made of, for example, metal and is formed in a cylindrical shape (for example, a cylindrical shape). One end side of the support portion 72 is bonded to the first housing 1 via the bonding portion 3. The bonding part 3 is, for example, an adhesive or a double-sided tape.

  By inputting an oscillation signal to the piezoelectric vibrator 10 from a control unit 50 described later, the piezoelectric vibrator 10 is vibrated and a sound wave is oscillated from the piezoelectric vibrator 10. The control unit 50 generates a modulation signal (a parametric speaker modulation signal) to be input to the piezoelectric vibrator 10. The transport wave of the modulation signal is, for example, an ultrasonic wave having a frequency of 20 kHz or higher, and specifically, an ultrasonic wave having a frequency of 100 kHz, for example. The control unit 50 controls the piezoelectric vibrator 10 according to information input from the outside.

  The parametric speaker modulates an ultrasonic carrier wave with an audible sound signal using a modulation method such as AM modulation, DSB modulation, SSB modulation, FM modulation, and radiates it while maintaining high directivity in the air. The audible sound is demodulated by the nonlinear phenomenon of sound waves in the air. Therefore, at a certain distance from the sound hole 20, the sound pressure of the audible sound to be demodulated becomes maximum.

  The number of sound holes 20 is arbitrary. There may be one or more sound holes 20.

  A liquid container 31 is disposed in the region of the distance between the first housing 1 and the second housing 2. The liquid container 31 is formed in, for example, a flat shape (for example, a flat rectangular parallelepiped shape), and an edge portion of the sound hole 20 in the first housing 1 and an edge portion of the sound hole 20 in the second housing 2. , And the sound hole 20 is closed. The liquid container 31 is filled with, for example, air and liquid.

  The liquid container 31 is made of a material that transmits ultrasonic waves. Specifically, the liquid container 31 is made of, for example, a resin material such as acrylic or ABS.

  Further, in the liquid container 31, it is exposed in the part that becomes the sound path, that is, the part that faces the piezoelectric vibrator 10 (the part that is exposed in the first opening 1 a) and the second opening 2 a. A waterproof film (not shown) is affixed to each site. Examples of the waterproof membrane material having good waterproofness and sound transmission include polytetrafluoroethylene or a polyurethane polymer composite material.

  The audio output device 100 is further arranged offset from the sound hole 20, and has a liquid tank 33 for storing liquid, a liquid channel 34 for communicating the liquid tank 33 and the liquid container 31, and the volume of the liquid tank 33. And an actuator 32 (FIG. 3) for increasing and decreasing.

  The liquid can be selected in consideration of viscosity, for example, water, ethanol, or silicone synthetic oil. The viscosity of the liquid is generally about 100 times greater than that of air, and the coefficient of friction also increases substantially proportionally. For this reason, in the liquid container 31, it is possible to cause attenuation and nonlinear distortion of ultrasonic waves larger than air.

The actuator 32 increases or decreases the volume of the liquid tank 33 by, for example, an electromagnetic driving method, a piezoelectric driving method, or other driving methods.
Since the liquid tank 33 and the liquid container 31 communicate with each other via the liquid channel 34, when the volume of the liquid tank 33 decreases, the liquid is supplied to the liquid container 31 via the liquid channel 34.
Further, when the volume of the liquid tank 33 increases, the liquid in the liquid container 31 is sucked by the liquid tank 33 through the liquid channel 34.

  In the liquid container 31, an area not filled with liquid is filled with air. When the amount of liquid in the liquid container 31 decreases, the air expands and the pressure of the air decreases. When the amount of liquid in the liquid container 31 increases, air is compressed and the pressure of the air increases.

  As described above, the liquid container 31 closes the sound hole 20. The nonlinear distortion generated in the sound hole 20 can be controlled by adjusting the filling amount of the liquid in the liquid container 31. That is, as the amount of liquid in the liquid container 31 increases, the attenuation of ultrasonic waves and the nonlinear distortion in the liquid container 31 increase. For this reason, the distance (distance from the sound hole 20) at which the sound pressure of the audible sound becomes maximum tends to become shorter as the liquid amount in the liquid container 31 increases (see FIG. 4).

  As shown in FIG. 3, the audio output device 100 further includes an operation unit and display unit 40 that performs various display operations and also functions as an operation unit that receives an input operation by a user. That is, the operation unit / display unit 40 can be configured by, for example, a touch panel type liquid crystal display device and the like, and not only performs a simple display operation but also functions as a GUI (Graphical User Interface).

  The audio output device 100 further includes a control unit 50 that controls the operation of the piezoelectric vibrator 10, the actuator 32, and the operation unit / display unit 40. The control unit 50 includes a control / calculation unit and a storage unit, and a table 51 is stored and held in the storage unit.

  The table 51 includes a distance from the sound hole 20 at which the audible sound reproduced by demodulating the ultrasonic wave radiated from the sound hole 20 is maximized (hereinafter referred to as an audible sound pressure maximum distance), and the actuator 32. It includes information indicating the correspondence between the control parameters.

The audio output device 100 is configured so that the user can change the distance (distance from the sound hole 20) at which the sound pressure of the audible sound to be demodulated is maximum as required.
When the user inputs a desired distance (target distance) to the operation unit / display unit 40, the control unit 50 controls the actuator 32 in accordance with the input distance, whereby the volume of the liquid tank 33, In addition, the liquid amount in the liquid container 31 is adjusted to the optimum volume and liquid amount corresponding to the inputted distance. That is, the filling amount of the liquid in the liquid container 31 is adjusted to the optimum filling amount according to the input distance. As a result, sound can be output so that the sound pressure of the audible sound demodulated is maximized at a position separated from the sound hole 20 by the distance input by the user.
As described above, the audio output device 100 has an operation unit (operation unit / display unit 40) that receives a distance input operation, and the liquid amount adjustment unit demodulates the ultrasonic waves emitted from the sound hole 20. The liquid filling amount in the liquid container 31 is adjusted so that the audible sound reproduced by the above is maximized at a position away from the sound hole 20 by the distance input to the operation unit.

  Further, when controlling the operation of the actuator 32, the control unit 50 acquires the control parameter of the actuator 32 corresponding to the distance input by the user from the table 51, and uses the acquired control parameter to liquid tank 33. And the amount of liquid in the liquid container 31 are adjusted.

  The audio output device 100 is, for example, a mobile communication terminal device. In that case, the audio output device 100 has a communication unit (not shown) for realizing a communication function. Further, the audio output device 100 may realize a call function as a communication function. Furthermore, the audio output device 100 may have a music reproduction function as an example of the audio reproduction function.

  Next, a series of operations will be described with reference to FIGS.

First, in a normal state (for example, a state in which music is being played while waiting for an incoming call), for example, as shown in FIG. 6, a function selection button group 42 including various function selection buttons is used as an operation unit. It is displayed on the display screen 41 of the display unit 40. The function selection button group 42 includes a distance selection button 42a for performing a request operation for shifting to the distance selection mode.
In this state, the control unit 50 monitors the presence / absence of an operation on the distance selection button 42a (step S11 in FIG. 5). This monitoring state continues unless the distance selection button 42a is operated (if the determination in step S11 is N, the determination in step S11 is repeatedly executed).

  Thereafter, it is assumed that the distance selection button 42a of the function selection button group 42 is touched. This operation is detected by the touch panel type operation unit / display unit 40, and a detection signal indicating the detection is input from the operation unit / display unit 40 to the control unit 50.

Then, the control unit 50 determines that an operation for requesting transition to the distance selection mode has been performed (Y in step S11).
Subsequently, the control unit 50 shifts the operation mode of the audio output device 100 to the distance selection mode. At this time, the operation unit and display unit 40 displays, for example, a target distance selection window 43 as shown in FIG. 7 on the display screen 41 under the control of the control unit 50 (displays the target distance selection screen) (step) S12).

  As shown in FIG. 7, the target distance selection window 43 displays a target distance selection candidate 44 together with a message prompting a target distance selection operation (for example, a character string such as “Please select a target distance.”). Is done. For example, the target distance is selected as a selection candidate 44 so that the target distance can be selected in increments of 5 cm, such as 5-10 cm, 10-15 cm, 15-20 cm,..., 90-95 cm, 95-100 cm. It is displayed on the selection window 43. Furthermore, in the target distance selection window 43, for example, a cursor 45 used for selecting the target distance is displayed.

  In this state, the control unit 50 monitors the presence / absence of a selection operation for any of the selection candidates 44 for the target distance (step S13 in FIG. 5). This monitoring state continues unless any selection candidate 44 for the target distance is selected (if the determination in step S13 is N, the determination in step S13 is repeated).

For example, when the user performs a touch operation on a display location of 15 to 20 cm on the display screen 41, this operation is detected by the touch panel type operation unit and display unit 40, and detection indicating the detection is performed. A signal is input from the operation unit / display unit 40 to the control unit 50.
Then, the control unit 50 instructs the operation unit / display unit 40 to perform display control for moving the cursor 45 to the display position of 15 to 20 cm, and 15 to 20 cm is selected as the target distance (input is performed). ) (Y in step S13).

  Subsequently, the control unit 50 obtains a control parameter corresponding to the selected target distance from the table 51 (step S14), and displays a target distance switching confirmation window 46 as shown in FIG. (A confirmation screen for switching the target distance is displayed) (step S15).

  As shown in FIG. 8, in the confirmation window 46, for example, “Yes, a range of 15 to 20 cm has been selected as the target distance. Are you sure you want to change the setting of the ultrasonic speaker?” ”And“ No ”selection buttons 47 and a cursor 48 for selecting one of the selection buttons are displayed.

  In this state, the control unit 50 monitors the presence / absence of a selection operation for the “Yes” or “No” selection button (step S16 in FIG. 5). When “No” is selected (N in Step S16), the processing from Step S12 is repeated. When “Yes” is selected (Y in Step S16), the control unit 50 determines whether or not the target distance setting needs to be changed (Step S17). That is, it is determined whether or not the control parameter corresponding to the target distance set so far matches the control parameter corresponding to the currently selected target distance.

  As a result of the determination, if the control parameter corresponding to the target distance that has been set up to now and the control parameter corresponding to the target distance selected this time are the same, the control unit 50 does not need to change the setting. (N of step S18), that is, it is determined that the setting so far should be continued, and the processing of FIG.

On the other hand, when the control parameter corresponding to the target distance set so far is different from the control parameter corresponding to the target distance selected this time, the control unit 50 needs to change the setting (in step S18). Y), and by controlling the actuator 32 according to the control parameter acquired in the previous step S14, the liquid filling amount in the liquid container 31 is adjusted to the filling amount corresponding to the target distance (step S19). ).
Thereby, the liquid container 31 is set so that the audible sound reproduced by demodulating the ultrasonic wave radiated from the sound hole 20 becomes maximum at a position away from the sound hole 20 by the target distance selected by the user. The filling amount of the liquid inside can be adjusted.

  According to the embodiment as described above, the audio output device 100 includes the oscillation device 70 having the piezoelectric vibrator 10, the speaker control unit that inputs the modulation signal for the parametric speaker to the oscillation device 70, and the piezoelectric vibrator 10. The sound hole 20 that radiates the output ultrasonic wave, the liquid container 31 disposed in the sound hole 20, the operation unit / display unit 40 that acquires information indicating the target distance, and the operation unit / display unit 40 acquired. Since there is a liquid amount adjusting unit (for example, the liquid tank 33, the liquid channel 34, the actuator 32, and the control unit 50) that adjusts the filling amount of the liquid in the liquid container 31 according to the information, it is emitted from the sound hole 20. The liquid in the liquid container 31 is such that the audible sound reproduced by demodulating the ultrasonic wave is maximized at a position away from the sound hole 20 by the target distance selected by the user. It is possible to adjust the filling amount.

In the above embodiment, an opening / closing valve may be provided in the liquid flow path 34. In this case, by opening the on-off valve 34, the liquid tank 33 and the liquid container 31 communicate with each other via the liquid flow path 34, and the liquid can be circulated between the liquid tank 33 and the liquid container 31. . In addition, the flow of the liquid between the liquid tank 33 and the liquid container 31 is blocked by closing the on-off valve 34.
Further, a flow rate control valve for controlling the flow rate of the liquid flowing through the liquid channel 34 may be provided in the liquid channel 34.

  In the above embodiment, an example has been described in which the audio output device 100 acquires information indicating the target distance when the user performs an input (for example, selection) operation of the target distance on the operation unit and display unit 40. Information indicating the target distance may be acquired from a device external to the audio output device 100.

DESCRIPTION OF SYMBOLS 1 1st housing | casing 1a 1st opening 2 2nd housing | casing 2a 2nd opening 3 Bonding part 10 Piezoelectric vibrator 20 Sound hole 31 Liquid container 32 Actuator 33 Liquid tank 34 Liquid flow path 40 Operation part and display part 41 Display screen 42 Function selection button group 42a Distance selection button 43 Target distance selection window 45 Cursor 46 Confirmation window 47 Selection button group 48 Cursor 50 Control unit 51 Table 70 Oscillator 71 Vibration member 72 Support unit 100 Audio output device

Claims (5)

An oscillation device having a piezoelectric vibrator;
A speaker control unit for inputting a modulation signal for a parametric speaker to the oscillation device;
A sound hole for emitting ultrasonic waves output from the piezoelectric vibrator;
A liquid container disposed in the sound hole;
An acquisition unit for acquiring information indicating a target distance;
A liquid amount adjusting unit that adjusts a filling amount of the liquid in the liquid container according to the information acquired by the acquiring unit;
An audio output device comprising: The liquid volume adjusting unit is
A liquid tank disposed offset from the sound hole and storing the liquid;
A liquid flow path for communicating the liquid tank and the liquid container;
An actuator for increasing or decreasing the volume of the liquid tank;
The audio output device according to claim 1, comprising: A first housing that houses the oscillation device;
A second housing covering the periphery of the first housing;
Have
A first opening for communicating the inside and the outside of the first housing is formed at a position facing the piezoelectric vibrator in the first housing.
A second opening that communicates the inside and the outside of the second housing is formed at a position facing the first opening in the second housing,
The sound hole includes the first and second openings,
3. The audio output device according to claim 1, wherein the liquid container is disposed in a region having a space between the first housing and the second housing. 4. A table showing a correspondence relationship between the distance from the sound hole where the audible sound reproduced by demodulating the ultrasonic wave radiated from the sound hole is maximized, and the control parameter of the liquid amount adjusting unit; Having a storage section stored,
The liquid amount adjusting unit acquires the control parameter corresponding to the information acquired by the acquiring unit from the table, and adjusts the filling amount of the liquid in the liquid container using the acquired control parameter. The audio output device according to claim 1, wherein the audio output device is an audio output device.   The audio output device according to claim 1, wherein the acquisition unit is an operation unit that receives an input operation of the target distance.

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