Acoustic generator, acoustic generating device, and electronic device
An acoustic generator according to an embodiment is provided with a vibration body, an exciter (piezoelectric vibration element), and a coating portion. The exciter is joined onto the vibration body through a joining portion. The coating portion is provided from the exciter to the vibration body. Furthermore, at least a part of an outer periphery of the joining portion is positioned inside of an outer periphery of the exciter, and a part of the coating portion is interposed between the vibration body and the exciter.
1. An acoustic generator comprising:
a vibration body;
an exciter configured to vibrate upon input of an electric signal;
a joining portion configured to join the exciter onto the vibration body; and
a coating portion provided from the exciter to the vibration body; wherein
at least a part of an outer periphery of the exciter extends beyond an outer periphery of the joining portion, and a part of the coating portion is interposed between a surface of the vibration body and a surface of the exciter, the surfaces facing each other.
2. The acoustic generator according to claim 1 , wherein
the part of the coating portion has an asymmetric shape with respect to a central axis of the exciter, the central axis being orthogonal to a vibration surface of the vibration body.
3. The acoustic generator according to claim 1 , wherein
the joining portion is in contact with the part of the coating portion, and
an outer periphery surface of the joining portion being in contact with the part of the coating portion has concavity and convexity.
4. The acoustic generator according to claim 1 , wherein
the outer periphery surface of the joining portion has a wedge shaped groove when viewed from a section orthogonal to the vibration surface of the vibration body.
5. The acoustic generator according to claim 1 , wherein
a whole of the outer periphery of the joining portion is positioned inside of the outer periphery of the exciter, and the part of the coating portion is arranged over an entire periphery along the outer periphery of the exciter.
6. The acoustic generator according to claim 1 , wherein
a part of the outer periphery of the exciter extends beyond the outer periphery of the joining portion, and wherein a part of the joining portion extends beyond the outer periphery of the exciter.
7. The acoustic generator according to claim 1 , wherein
the part of the coating portion interposed between the surfaces facing each other has a void.
8. The acoustic generator according to claim 1 , wherein
a gap exists between the part of the coating portion interposed between the surfaces facing each other and at least one of the vibration body, the exciter, and the joining portion.
9. An acoustic generating device comprising:
the acoustic generator according to claim 1 ; and
a housing configured to place therein the acoustic generator.
10. An electronic device comprising:
the acoustic generator according to claim 1 ;
an electronic circuit connected to the acoustic generator; and
a case configured to place therein the electronic circuit and the acoustic generator,
wherein the electronic device has a function to cause the acoustic generator to generate a sound.
11. The acoustic generator according to claim 1 , wherein
the coating portion is provided from the exciter to the vibration body to coat the exciter and the vibration body.