Bone conduction speaker and compound vibration device thereof
The present disclosure relates to a bone conduction speaker and its compound vibration device. The compound vibration device comprises a vibration conductive plate and a vibration board, the vibration conductive plate is set to be the first torus, where at least two first rods inside it converge to its center; the vibration board is set as the second torus, where at least two second rods inside it converge to its center. The vibration conductive plate is fixed with the vibration board; the first torus is fixed on a magnetic system, and the second torus comprises a fixed voice coil, which is driven by the magnetic system. The bone conduction speaker in the present disclosure and its compound vibration device adopt the fixed vibration conductive plate and vibration board, making the technique simpler with a lower cost; because the two adjustable parts in the compound vibration device can adjust both low frequency and high frequency area, the frequency response obtained is flatter and the sound is broader.
1. A bone conduction speaker, comprising:
a vibration device comprising a vibration conductive plate and a vibration board, wherein
the vibration conductive plate is physically connected with the vibration board, vibrations generated by the vibration conductive plate and the vibration board have at least two resonance peaks, frequencies of the at least two resonance peaks being catchable with human ears, and sounds are generated by the vibrations transferred through a human bone;
a microphone configured to receive a first signal including a voice signal and a first vibration signal; and
a vibration sensor configured to receive a second vibration signal, wherein
the microphone and the vibration sensor are configured such that the first vibration signal can be offset with the second vibration signal.
2. The bone conduction speaker according to claim 1 , further comprising a housing, wherein the bone conduction speaker, the microphone, and the vibration sensor are located in the housing.
3. The bone conduction speaker according to claim 1 , wherein
an amplitude-frequency response of the vibration sensor to the second vibration signal is same as an amplitude-frequency response of the microphone to the first vibration signal; or
a phase-frequency response of the vibration sensor to the second vibration signal is same as a phase-frequency response of the microphone to the first vibration signal.
4. The bone conduction speaker according to claim 1 , wherein a cavity volume of the vibration sensor is greater than a cavity volume of the microphone such that the microphone and the vibration sensor have an approximately same frequency response to the vibration of the vibration source.
5. The bone conduction speaker according to claim 1 , further comprising a signal processing unit configured to make the first vibration signal offset with the second vibration signal and output the voice signal.
6. The bone conduction speaker according to claim 1 , wherein the microphone includes a front cavity or a back cavity.
7. The bone conduction speaker according to claim 6 , wherein the front cavity includes at least one opening on a top or a side wall of the front cavity.
8. The bone conduction speaker according to claim 1 , wherein the vibration sensor includes a closed microphone, or a dual-link microphone.
9. The bone conduction speaker according to claim 8 , wherein the closed microphone includes a closed front cavity and a closed back cavity.
10. The bone conduction speaker according to claim 8 , wherein the dual-link microphone includes an open front cavity and an open back cavity.
11. The bone conduction speaker according to claim 1 , wherein the microphone is an air conduction microphone and the vibration sensor is a bone conduction microphone.
12. The bone conduction speaker according to claim 1 , wherein the microphone and the vibration sensor are both micro-electromechanical system microphones.
13. The bone conduction speaker according to claim 1 , wherein the microphone and the vibration sensor are independently connected to a same housing.
14. The bone conduction speaker according to claim 13 , wherein the microphone and the vibration sensor are located at adjacent positions on the housing or at symmetrical positions on the housing with respect to the bone conduction speaker.
15. The bone conduction speaker according to claim 13 , wherein a connection between the microphone and the housing or a connection between the vibration sensor and the housing includes at least one of a cantilever connection, a peripheral connection, or a substrate connection.
16. The bone conduction speaker according to claim 1 , wherein the vibration conductive plate includes a first torus and at least two first rods, the at least two first rods converging to a center of the first torus.
17. The bone conduction speaker according to claim 14 , wherein the vibration board includes a second torus and at least two second rods, the at least two second rods converging to a center of the second torus.
18. The bone conduction speaker according to claim 15 , wherein the first torus is fixed on a magnetic component.
19. The bone conduction speaker according to claim 1 , wherein a lower resonance peak of the at least two resonance peaks is equal to or lower than 900 Hz.
20. The bone conduction speaker according to claim 19 , wherein a higher resonance peak of the at least two resonance peaks is equal to or lower than 9500 Hz.