JP5696434B2 - Electronics - Google Patents

Description

  The present invention relates to an electronic device having a function of outputting sound.

  In recent years, the demand for mobile terminals such as mobile phones and laptop computers has been increasing. In particular, the development of thin mobile terminals with commercial functions such as videophones, video playback, and hands-free phone functions is underway. In these developments, there is an increasing demand for electroacoustic transducers that are small and have high output. Conventionally, an electrodynamic electroacoustic transducer is used as an electroacoustic transducer in an electronic device such as a mobile phone. This electrodynamic electroacoustic transducer is composed of a permanent magnet, a voice coil, and a diaphragm. However, the electrodynamic electroacoustic transducer is limited in thickness because of its operation principle and structure. Therefore, it is expected to use the piezoelectric vibrator as a parametric speaker.

  Patent Document 1 describes that in a portable information terminal, a transparent piezoelectric film diaphragm is provided above a display screen.

JP 2003-244792 A

  In recent portable electronic devices, there is a significant need to increase the screen while suppressing an increase in size.

  The objective of this invention is providing the electronic device which can enlarge a screen, suppressing an enlargement.

According to the present invention, a display screen;
An operation button provided on the same surface as the display screen and having a hollow portion;
A piezoelectric vibrator incorporated in the hollow portion in a direction in which an oscillation surface faces the surface of the operation button;
Control means for inputting an audio signal to the piezoelectric vibrator;
An electronic device is provided.

  ADVANTAGE OF THE INVENTION According to this invention, a screen can be enlarged, suppressing the enlargement of an electronic device.

It is a top view which shows the structure of the electronic device which concerns on 1st Embodiment. It is AA 'sectional drawing of FIG. FIG. 3 is an enlarged view of one of the operation buttons shown in FIG. 2. It is sectional drawing which shows the principal part of the electronic device which concerns on 2nd Embodiment.

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

(First embodiment)
FIG. 1 is a plan view illustrating a configuration of an electronic device 300 according to the first embodiment. The electronic device 300 is a portable electronic device and includes a display screen 200 and operation buttons 100. The operation button 100 is provided on the same surface as the display screen 200. The operation button 100 has a hollow portion 112 (see FIG. 3). A piezoelectric vibrator 120 (see FIG. 3) is incorporated in the hollow portion 112. The piezoelectric vibrator 120 faces the direction in which the oscillation surface faces the surface of the operation button 100. An audio signal is input from the control unit 50 to the piezoelectric vibrator 120. That is, the piezoelectric vibrator 120 functions as a sound source of the speaker. Details will be described below.

  In the present embodiment, the electronic device 300 is a mobile communication terminal. The electronic device 300 has a plurality of operation buttons 100 arranged in a matrix (array). The piezoelectric vibrator 120 is incorporated in each of the plurality of operation buttons 100.

  2 is a cross-sectional view taken along the line AA ′ of FIG. Each of the plurality of operation buttons 100 is attached to the housing 310 of the electronic device 300 via the spring 102. A control unit 50 is connected to the piezoelectric vibrator 120 of each operation button 100 via a signal generation unit 52. The signal generation unit 52 generates an electrical signal input to the piezoelectric vibrator 120, for example, a modulation signal in a parametric speaker. The transport wave of the modulation signal is an ultrasonic wave having a frequency of 20 kHz or higher, for example, an ultrasonic wave having a frequency of 100 kHz. The control unit 50 controls the signal generation unit 52 based on information input from the outside. Information input to the control unit 50 is an audio signal. And the control part 50 and the signal generation part 52 change the timing which each piezoelectric vibrator 120 oscillates a transport wave, in order to control the directivity of a parametric speaker. And the audible sound is reproduced | regenerated by the synthesis | combination of the transport wave which each piezoelectric vibrator 120 oscillated in the air.

  Here, the principle of a general parametric speaker will be described. A parametric speaker emits ultrasonic waves (transport waves) subjected to AM modulation, DSB modulation, SSB modulation, and FM modulation from each of a plurality of oscillation sources into the air, and due to nonlinear characteristics when the ultrasonic waves propagate into the air. , To make an audible sound appear. Non-linear here means that the flow changes from laminar flow to turbulent flow when the Reynolds number indicated by the ratio between the inertial action and the viscous action of the flow increases. Since the sound wave is slightly disturbed in the fluid, the sound wave propagates nonlinearly. Particularly in the ultrasonic frequency band, the nonlinearity of the sound wave can be easily observed. And when an ultrasonic wave is radiated in the air, harmonics accompanying the nonlinearity of the sound wave are remarkably generated. The sound wave is a dense state where the density of the molecular density is generated in the air. When it takes time for air molecules to recover from compression, air that cannot be recovered after compression collides with air molecules that continuously propagate, and a shock wave is generated. An audible sound is generated by this shock wave.

  FIG. 3 is an enlarged view of one of the operation buttons 100 shown in FIG. The piezoelectric vibrator 120 is formed of, for example, a piezoelectric film and is polarized in the thickness direction. The thickness of the piezoelectric vibrator 120 is, for example, 0.5 mm or less. The piezoelectric vibrator 120 has electrodes (not shown) formed on both surfaces, and a signal voltage is applied from the signal generator 52 between these electrodes. The piezoelectric vibrator 120 is located in a hollow portion 112 provided in the housing 110 of the operation button 100. The edge of the piezoelectric vibrator 120 is fixed to the inner wall of the hollow portion 112. The piezoelectric vibrator 120 may be made of ceramics.

  A through hole 114 is provided on the surface of the housing 110. The through hole 114 connects the hollow portion 112 and the outside. The ultrasonic wave oscillated by the piezoelectric vibrator 120 is radiated to the outside through the through hole 114.

  Next, the operation and effect of this embodiment will be described. According to this embodiment, the operation button 100 incorporates the piezoelectric vibrator 120 that functions as a speaker. For this reason, it is not necessary to ensure the area | region which installs only a speaker in the housing | casing of the electronic device 300. FIG. For this reason, the display screen 200 can be enlarged while suppressing the enlargement of the electronic device 300.

  In particular, in this embodiment, a parametric speaker having an array structure is employed as the speaker. When the parametric speaker having the array structure is employed, the area occupied by the speaker in the electronic device 300 becomes large. On the other hand, in the present embodiment, since the piezoelectric vibrator 120 is incorporated in the operation buttons 100 arranged in an array, the display screen 200 needs to be small even if a parametric speaker having an array structure is employed. Disappear.

  Moreover, since the through-hole 114 is provided in the housing | casing 110 of the operation button 100 and a transport wave is radiate | emitted from the through-hole 114, the directivity of a parametric speaker is also improved. Further, since the piezoelectric vibrator 120 is located inside the casing 110 of the operation button 100, the durability of the piezoelectric vibrator 120 is also improved. Moreover, it can also suppress that the electronic device 300 becomes thick due to a speaker.

(Second Embodiment)
FIG. 4 is a cross-sectional view illustrating a main part of the electronic device 300 according to the second embodiment, and corresponds to FIG. 3 in the first embodiment. The electronic device 300 according to the present embodiment is the same as the electronic device according to the first embodiment except that a plurality of piezoelectric vibrators 120 are provided in parallel to each other in the hollow portion 112 of the casing 110 of each operation button 100. The configuration is the same as that of the device 300.

  Also according to this embodiment, the same effect as that of the first embodiment can be obtained. Further, since the plurality of piezoelectric vibrators 120 are provided in the hollow portion 112 of the operation button 100, the output of the speaker can be increased.

  The structure of the piezoelectric vibrator 120 disposed in the hollow portion 112 is not limited to the structure shown in the first and second embodiments.

As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.
Hereinafter, examples of the reference form will be added.
1.
A display screen;
An operation button provided on the same surface as the display screen and having a hollow portion;
A piezoelectric vibrator incorporated in the hollow portion in a direction in which an oscillation surface faces the surface of the operation button;
Control means for inputting an audio signal to the piezoelectric vibrator;
Electronic equipment comprising.
2.
1. In the electronic device described in
The operation button further includes a through-hole connecting the hollow portion and the outside on the surface,
The control means is an electronic device that inputs a modulation signal in a parametric speaker to the piezoelectric vibrator.
3.
1. Or 2. In the electronic device described in
A plurality of the operation buttons arranged in a matrix;
The piezoelectric vibrator is an electronic device incorporated in each of the plurality of operation buttons.
4).
1. ~ 3. In the electronic device according to any one of
The piezoelectric vibrator is an electronic device in which an edge is fixed to an inner wall of the hollow portion.

DESCRIPTION OF SYMBOLS 50 Control part 52 Signal generation part 100 Operation button 102 Spring 110 Case 112 Hollow part 114 Through-hole 120 Piezoelectric vibrator 200 Display screen 300 Electronic device 310 Case

Claims (3)

A display screen;
An operation button having a hollow portion and a housing surrounding the hollow portion;
A piezoelectric vibrator incorporated in the hollow portion;
Control means for inputting an audio signal to the piezoelectric vibrator;
With
The casing has an outer wall surface arranged on the same plane as the display screen,
The piezoelectric vibrator has an oscillation surface disposed in a state of facing the outer wall surface,
A through-hole that connects the hollow portion and the outside is formed in the outer wall surface,
The through hole is not blocked,
The control means inputs a modulation signal in a parametric speaker to the piezoelectric vibrator,
The piezoelectric vibrator oscillates an ultrasonic wave having a frequency of 20 kHz or more ,
An edge of the piezoelectric vibrator is fixed to an intermediate portion between an upper end and a lower end of an inner wall of the hollow portion standing upright with respect to the piezoelectric vibrator, and a portion of the inner wall standing upright is An electronic apparatus which is located on one side of the piezoelectric vibrator and the other part of the vertically standing inner wall is located on the other side of the piezoelectric vibrator . The electronic device according to claim 1,
The said through-hole is an electronic device which has penetrated the said outer wall surface in the direction orthogonal to the said display screen. The electronic device according to claim 1 or 2,
A plurality of the operation buttons arranged in a matrix;
The piezoelectric vibrator is an electronic device incorporated in each of the plurality of operation buttons.

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