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Piezoelectric speaker, piezoelectric sound device using same, and sensor with siren

A piezoelectric speaker and piezoelectric technology, applied in the direction of sensors, piezoelectric/electrostrictive transducers, resonant transducers, sensor types, etc., can solve problems such as low sound pressure and inability to obtain sufficient sound pressure, and achieve improved sound pressure effect

Inactive Publication Date: 2011-11-30
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, in such a piezoelectric speaker, the sound pressure in the low range is still low, and sufficient sound pressure cannot be obtained

Method used

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  • Piezoelectric speaker, piezoelectric sound device using same, and sensor with siren
  • Piezoelectric speaker, piezoelectric sound device using same, and sensor with siren
  • Piezoelectric speaker, piezoelectric sound device using same, and sensor with siren

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0084] refer to Figure 1 to Figure 4 The piezoelectric speaker according to Embodiment 1 of the present invention will be described. The piezoelectric speaker 1 of the present embodiment is characterized by including a piezoelectric vibrator 2, a film-like body 3 that is provided around the piezoelectric vibrator 2 and holds the piezoelectric vibrator 2, and a frame 4 that supports the outer peripheral portion of the film-like body 3, The membrane body 3 has a bellows structure having peaks and valleys in the outer circumferential direction according to the natural frequency of the in-phase mode in which the abdomen and the nodes are formed concentrically, and the sound generator is formed by the piezoelectric vibrator and the membrane body. The piezoelectric vibrator 2 includes a piezoelectric body 21 composed of a piezoelectric element, and a metal plate as a plate-like body 22 having a diameter larger than that of the piezoelectric body 21 and concentrically attached to th...

Embodiment approach 2

[0109] Next, Embodiment 2 of the present invention will be described.

[0110] In this embodiment, as Figure 13 As shown in (a) to (c), the bellows structure of the membrane body 3 is characterized in that the bellows and the abdomen of the vibration mode correspond one-to-one, and the bellows ( peaks and valleys). Here, the structure of the piezoelectric speaker is the same as that of the first embodiment except for the accordion shape.

[0111] refer to Figure 13 The operation in which the piezoelectric speaker 1 of the present embodiment configured as described above emits radiated sound will be described. Figure 13 (a) to (c) show the vibration modes ( Figure 13 (a)), the displacement of the vibration part of the piezoelectric speaker ( Figure 13 (b)) and the composition of membranous bodies ( Figure 13 (c)). Here, when a signal voltage for radiating sound is applied to the piezoelectric body 21, the piezoelectric body 21 contracts and expands, but the plate-l...

Embodiment approach 3

[0115] Next, Embodiment 3 of the present invention will be described.

[0116] Next, the results of the measurement of the third resonance will be described.

[0117] exist Figure 14 in indicates that for the Figures 1 to 4 The same piezoelectric vibrator 2 shown in the above-mentioned first embodiment is formed with a size of 35Φ, and when only the piezoelectric vibrator 2 of 35Φ is provided (curve a), the piezoelectric vibrator 2 of 35Φ is connected to the film-like body 3 of 50Φ. In the case (curve b) and the case where the piezoelectric vibrator 2 of 35Φ is connected to the membrane-like body 3 having the accordion of 50Φ (curve c), the relationship between the sound pressure and the resonance frequency was measured.

[0118] in addition, Figure 15 is an enlarged view of the vicinity of the third resonance point.

[0119] As can be seen from this figure, the curve b represents the increase in the sound pressure in the low frequency range, and the curve c represents ...

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PUM

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Abstract

Disclosed is a piezoelectric speaker with a large sound pressure, a piezoelectric audio device, and a sensor with an alert device attached, employing same, with respect to a low frequency region and a high frequency region. A piezoelectric speaker (1) comprises a piezoelectric oscillator (2), further comprising a piezoelectric body (21) formed from a piezoelectric element, and a plate, further comprising a diameter greater than the diameter of the piezoelectric body (21), the plate being mounted upon a surface of the piezoelectric body (21) in a concentric state, and a film body (3), which is installed upon a periphery of the piezoelectric oscillator (2) and maintains the piezoelectric oscillator in an elastic state, wherein the film body (3) further comprises a rough and fine portion further comprising a physically rough portion that may be a peak portion (3M); and / or a valley portion (3V) upon an external circumference direction thereof, the film body (3) is further positioned to correspond to a fixed frequency of an in-phase mode wherein peaks, valleys, and nodes are formed in a concentric circle, and the piezoelectric oscillator (2) and the film body (3) form a sound emission body.

Description

technical field [0001] The present invention relates to a piezoelectric speaker, a piezoelectric acoustic device using the same, and a sensor with an alarm device, and in particular, to improvement of sound pressure of a piezoelectric speaker using a piezoelectric element. Background technique [0002] A piezoelectric speaker using a piezoelectric vibrator in which a piezoelectric element is bonded to a metal plate has been conventionally known. The piezoelectric speaker has a thin and simple structure compared with the dynamic speaker, so it can be reduced in size and is also inexpensive. However, such a piezoelectric speaker has a problem that the sound pressure in the vicinity of the resonance frequency is high, but the sound pressure in other frequencies, particularly in the low frequency region, is small. In this specification, the low frequency region (hereinafter referred to as the low region) refers to the region below about 1 kHz, the high frequency region (hereina...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04R17/00H04R1/28H04R1/34
CPCH04R1/345H04R7/04H04R17/00H04R7/20H04R2231/003H04R2307/207H04R17/10
Inventor 福岛实北田耕作赤坂修西川哲广
Owner PANASONIC CORP