JP2012216897A - Oscillation device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oscillation device that automatically switches between hands-free and non-hands-free modes and that is prevented from increasing in size.SOLUTION: Each of a plurality of oscillation elements 30 has a vibrating member 10 and a piezoelectric element 20. The piezoelectric elements 20 are provided on the respective vibrating members 10. A frame 40 holds the oscillation elements 30. The oscillation elements 30 are arranged in an array. Proximity sensors 32 form the same array as that of the oscillation elements 30, and detect presence of an object, for example a human body, in the proximity thereof. Based on the detection result of the proximity sensors 32, a control section 50 controls magnitude of input to the oscillation elements 30.

Description

  The present invention relates to an oscillation device and an electronic apparatus having a piezoelectric element as an oscillation source.

    One type of speaker is used as an oscillation source in which a piezoelectric element is fixed on a vibrating member. This type of speaker is characterized in that it is easy to miniaturize compared to an electrodynamic speaker using a voice coil and a magnet. A speaker using a piezoelectric element flexures and vibrates the diaphragm by mounting the piezoelectric element on the diaphragm.

  On the other hand, Patent Document 1 describes that a mobile phone terminal performs a predetermined notification operation when voice data is received when a caller is away from a receiving speaker by a predetermined distance or more during a call. .

JP 2006-245919 A

  The present inventor considered that an electronic device having an audio output function increases the opportunity to listen to audio output hands-free. In such a case, if the user switches between hands-free one by one, a load is imposed on the user. On the other hand, downsizing of electronic devices is desired.

  The objective of this invention is providing the oscillation apparatus and electronic device which can switch automatically whether it is hands-free and can suppress enlargement.

According to the present invention, there are a plurality of oscillation elements arranged in an array having a vibration member and a plurality of piezoelectric elements provided on the vibration member;
A frame for holding the plurality of oscillation elements;
A proximity sensor that is held by the frame and constitutes the same array as the oscillation element, and detects that an object is close,
There is provided an oscillating device comprising control means for controlling the magnitude of input to the plurality of oscillating elements based on the detection result of the proximity sensor.

  According to the present invention, an electronic apparatus having the above-described oscillation device is provided.

  ADVANTAGE OF THE INVENTION According to this invention, it can switch automatically whether it is hands free, and can suppress enlarging.

It is a figure which shows the structure of the oscillation apparatus which concerns on embodiment. It is sectional drawing which shows the structure of an oscillation element. It is a figure which shows the structure of the electronic device which has an oscillation apparatus shown in FIG.

  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.

  FIG. 1 is a diagram illustrating a configuration of the oscillation device according to the embodiment. FIG. 2 is a cross-sectional view showing the configuration of the oscillation element 30. The oscillation device includes a plurality of oscillation elements 30, a frame body 40, a proximity sensor 32, and a control unit 50. Each of the oscillation elements 30 includes the vibration member 10 and the piezoelectric element 20. The piezoelectric element 20 is provided on the vibration member 10. The frame body 40 holds a plurality of oscillation elements 30. The plurality of oscillation elements 30 are arranged in an array. The proximity sensor 32 constitutes the same array as the oscillation element 30 and detects that an object (for example, a human body: in the following description, the object is a human body) is close. The control unit 50 controls the magnitudes of inputs to the plurality of oscillation elements 30 based on the detection result of the proximity sensor 32.

  That is, the control unit 50 reduces the input to the oscillation element 30 when the proximity sensor 32 detects that a human body is approaching. Further, when the proximity sensor 32 detects that the human body is separated, the control unit 50 increases the input to the oscillation element 30. For example, when the distance to the human body is equal to or less than the threshold value, the control unit 50 determines that it is not hands-free and reduces the output. In addition, when the distance to the human body exceeds the threshold, the control unit 50 determines that the hands are free and increases the output. For this reason, it can be switched automatically whether it is hands-free. Moreover, since the proximity sensor 32 comprises the same array as the oscillation element 30, it can suppress that an oscillation apparatus enlarges. Details will be described below.

  The vibration member 10 has a sheet shape, and the end portion is not constrained. The vibrating member 10 adjusts the basic resonance frequency of the piezoelectric element 20. The fundamental resonance frequency of the mechanical vibrator depends on the load weight and compliance. Since the compliance is the mechanical rigidity of the vibrator, the basic resonance frequency of the piezoelectric element 20 can be controlled by controlling the rigidity of the vibration member 10. The thickness of the vibration member 10 is preferably 5 μm or more and 500 μm or less. Further, the vibration member 10 preferably has a longitudinal elastic modulus, which is an index indicating rigidity, of 1 GPa or more and 500 GPa or less. When the rigidity of the vibration member 10 is too low or too high, there is a possibility that characteristics and reliability as a mechanical vibrator are impaired. The material constituting the vibration member 10 is not particularly limited as long as it is a material having a high elastic modulus with respect to the piezoelectric element 20 that is a brittle material, such as metal or resin, but phosphor bronze or the like in terms of workability and cost. Stainless steel or the like is preferable.

  The piezoelectric element 20 is formed of piezoelectric ceramics such as PZT. However, the piezoelectric element 20 may be formed of a polymer material exhibiting piezoelectric characteristics, such as polyvinylidene fluoride.

  In the present embodiment, the oscillation elements 30 are arranged in a matrix. The frame body 40 holds the entire circumference of the edge of the vibration member 10 of each oscillation element 30.

  In the present embodiment, the proximity sensor 32 has the same structure as the oscillation element 30. That is, in this embodiment, at least one of the oscillation elements 30 arranged in a matrix is used as the proximity sensor 32.

  The control unit 50 generates a drive signal based on an audio signal input from the outside, and inputs the generated drive signal to each piezoelectric element 20. When the oscillation device is caused to function as a speaker that directly outputs audible sound, the control unit 50 generates a drive signal by amplifying the audio signal. When the oscillation device functions as a parametric speaker, the control unit 50 modulates audio data (original signal) input from the outside to generate modulation data for the parametric speaker, and generates a drive signal based on this data. To do. The frequency of this drive signal is the nth-order resonance frequency of the piezoelectric element 20.

  When the control unit 50 uses the oscillation device as a parametric speaker, the proximity sensor 32 detects a sound wave having the same frequency as the sound wave oscillated by the oscillation element 30, and indicates that the human body has approached based on the magnitude of the detected value. To detect. That is, when a person approaches, the sound wave generated by the oscillation element 30 is reflected by the person. The proximity sensor 32 detects whether or not a person has approached by detecting the intensity of the reflected sound wave.

  FIG. 3 is a diagram illustrating a configuration of the electronic apparatus 100 including the oscillation device illustrated in FIG. The electronic device 100 is a portable electronic device such as a portable communication terminal, a portable game device, a portable music player, or a portable video player. In the example illustrated in FIG. 3, the electronic device 100 is a foldable mobile communication terminal having two housings. The oscillation element 30 and the proximity sensor 32 are built in a casing in which the display 102 is provided among the two casings of the electronic device 100. The control unit 50 may be provided in the same casing as the oscillation element 30 and the proximity sensor 32, or may be provided in a casing opposite to this.

  Next, the operation and effect of this embodiment will be described. According to the present embodiment, the control unit 50 reduces the input to the oscillation element 30 when the proximity sensor 32 detects that a human body has approached. Further, when the proximity sensor 32 detects that the human body is separated, the control unit 50 increases the input to the oscillation element 30. For this reason, it can be switched automatically whether it is hands-free. Moreover, since the proximity sensor 32 comprises the same array as the oscillation element 30, it can suppress that an oscillation apparatus enlarges.

  Further, as described above, the proximity sensor 32 detects the sound wave oscillated from the oscillating element 30 and reflected by the human body, and detects whether the person is close by detecting the strength of the detected sound wave. . When the oscillation element 30 functions as a parametric speaker, the oscillation element 30 uses the resonance frequency of the piezoelectric element 20 as a carrier wave. Further, since the proximity sensor 32 has the same structure as the oscillation element 30, the resonance frequency of the proximity sensor 32 is the same as the resonance frequency of the oscillation element 30. Therefore, the detection sensitivity of the proximity sensor 32 is increased.

  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.

DESCRIPTION OF SYMBOLS 10 Vibration member 20 Piezoelectric element 30 Oscillation element 32 Proximity sensor 40 Frame 50 Control part 100 Electronic device 102 Display

Claims (4)

A plurality of oscillation elements arranged in an array having a vibration member and a plurality of piezoelectric elements provided on the vibration member;
A frame for holding the plurality of oscillation elements;
A proximity sensor that is held by the frame and constitutes the same array as the oscillation element, and detects that an object is close,
Control means for controlling the magnitude of input to the plurality of oscillation elements based on the detection result of the proximity sensor;
An oscillation device comprising: The oscillation device according to claim 1,
An oscillation device in which the control means inputs a modulation signal as a parametric speaker to the plurality of oscillation elements. The oscillation device according to claim 2,
The proximity sensor has the same structure as the oscillation element, detects a sound wave having the same frequency as the sound wave oscillated by the oscillation element, and detects that an object has approached based on the magnitude of the detection value. An oscillating device.   The electronic device which has an oscillation apparatus as described in any one of Claims 1-3.

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