Patent Application
20140301579
The present invention generally relates to an acoustic device, and more particularly, to a vibrating acoustic device for generating high-frequency, medium-frequency and low-frequency acoustic waves.
With the rapid development of technologies, the design of electronic devices, such as cellular phones, PDAs (personal digital assistants), and so on, is being driven by the marketplace towards providing more and more multimedia functions. At the same time, consumer's demand has been continuing to push a dramatic reduction in the size of the electronic devices.
To comply with the multimedia requirements and reduce the size of the electronic devices, most electronic devices today include an vibrating acoustic device for generating audible sounds through vibration. The vibrating acoustic device comprises a holder, a vibrating system and a magnetic system received in the holder, respectively. The vibrating system comprises a coil and a diaphragm driven by the coil. Such an acoustic device only provides sounds with a certain range of frequency, e.g. high frequency sound, or mediate frequency sound. If an electronic device need full frequency band sounds, three acoustic devices are needed to perform the high frequency sound, mediate frequency sound, and low frequency sound, respectively, which obviously increases the cost.
Referring to
The frame 2 comprises a lower panel 21, a cover 22 mounted on the lower panel 21, a receiving space 23 formed by the lower panel 21 and the cover 22, and an acoustic hole 24 formed in the upper cover 22 and opposite to the lower panel 21.
The vibrating unit 1 comprises a holder 11, a first vibrating system 12 mounted on a lower portion of the holder 11, a second vibrating system 13 attached on an upper portion of the holder 11, and a magnetic system 4 received in the holder 11. The holder 11 has a hollow space for receiving the magnetic system 4 and the first and second vibrating systems 12, 13.
The magnetic system 4 comprises a first magnetic conduction member 41, a second magnetic conduction member 42 surrounding the first magnetic conduction member 41, a pair of first pole plates 43 attached on two sides of the first magnetic conduction member 41, a pair of second pole plates 44 attached on two sides of the second magnetic conduction member 42, and a magnetic gap 45 formed by outer surfaces of the first magnetic conduction member 41 and the first pole plates 43 together with the inner surfaces of the second magnetic conduction member 42 and the second pole plates 44. The first and second pole plates 43, 44 are made of magnetic conduction materials for effectively conducting magnetic fluxes, respectively. In this embodiment, the first and second magnetic conduction members 41, 42 are permanent magnets. Optionally, in an alternative embodiment, at least one of the first and second magnetic conduction members 41, 42 is a permanent magnet. And the first and second pole plates 43, 44 may be omitted for reducing the whole volume of the system.
The first vibrating system 12 comprises a vibrating plate 121 attached on a lower side of the holder 11 for resonating with a resonate media (e.g., the lower panel) to resonate and radiating sound in low-frequency region, a first coil 122 connected with the vibrating plate 121 and a first elastic supporting member 16 mounted the vibrating plate 121 and surrounded by the first coil 122 for elastically supporting the first magnetic conduction member 41 and providing a pre-pressure to the vibrating plate 121. The first coil 122 has an end inserted and suspended in the magnetic gap 45 and another end directly or indirectly connected with the vibrating plate 121 for driving the vibrating plate 121. An upper side of the vibrating plate 121 is attached on the lower part of the holder 11 and the lower side of the vibrating plate 121 is coupled with the lower panel 21. The magnetic system 4 cooperates with the first coil 122 to drive the vibrating plate 121 to vibrate for causing the lower panel 21 coupled with the vibrating plate 121 to resonate and radiate sound in low-frequency region, such as sounds with frequency under 600 Hz.
Optionally and improvably, the first vibrating system 12 further comprises a second elastic supporting member 15 sandwiched between the lower side of the holder 1 and a the second pole plate 44 for elastically supporting the holder 1. A part of the second pole plates also attach on the second elastic supporting member 15. The second elastic supporting member 15 surrounds the first coil 122. The first and second elastic supporting members 16, 15 are made of soft silicone or foam.
The second vibrating system 13 comprises a diaphragm 131 attached on an upper side of the holder 11 and partially exposed from the acoustic hole 24, and a second coil 132 having an end inserted and suspended in the magnetic gap 45 and another end directly or indirectly connected with the diaphragm 131 for driving the diaphragm 131. When the second coil 132 is activated by an electric audio signal, an electromagnetic force occurs between the second coil 132 and the magnetic system 4. This forces the diaphragm 131 to vibrate, thereby generating high and medium frequency sounds which are emitted to an environment perceivable by a listener.
The cover 22 has an upper plate 221 surrounding the acoustic hole 24 and a sidewall 222 extending from the upper plate 221 and coupled to the lower panel 21. The sidewall 222 comprises a supporting wall 223 for supporting the upper plate 221 and an elastic wall 224 connecting with the supporting wall 223 and the lower plane 21 for absorbing the vibration generating from the lower plane 21 and the first vibrating system 12 and for preventing the vibration generated by the lower plane 21 and the first vibrating system 12 influencing the sound quality of the second vibrating system 13.
The first magnetic conduction member 41 is spaced from the second magnetic conduction member 42 for forming the magnetic gap 45 shared by the first and second coils 122, 132. In an alternative embodiment, the first magnetic conduction member is partially connected with a second magnetic conduction member for dividing the magnetic gap discussed above into two separated parts, such as a first magnetic gap for partially receiving the first coil and a second magnetic gap for partially receiving the second coil. Additional, the second magnetic conduction member is capable of supporting the first magnetic conduction member, thereby the first elastic supporting member can be omitted.
In an alternative embodiment, referring to
While the present invention has been described with reference to the specific embodiments, the description of the invention is illustrative and is not to be construed as limiting the invention. Various of modifications to the present invention can be made to the exemplary embodiments by those skilled in the art without departing from the true spirit and scope of the invention as defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201320169064.5 | Apr 2013 | CN | national |
