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 having 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 in a range of 20 Hz-20000 Hz, and sounds are generated by the vibrations transferred through a human bone;
an ear hook, wherein the ear hook is configured to contact with the head of a user, one or more contact points of the ear hook and the head of the user include a vibration fulcrum of the vibration device when the vibration device vibrates; and
at least one button, wherein the at least one button is configured for user operation, and a distance between a center of a button of the at least one button and the vibration fulcrum is not greater than a distance between a center of the vibration device and the vibration fulcrum.
2. The bone conduction speaker according to claim 1 , wherein the center of the button of the at least one button includes a center of mass or a centroid of the button.
3. The bone conduction speaker according to claim 1 , wherein the vibrations of the vibration device is indicated by a first ratio of a first distance to a second distance, and a second ratio of a mass of the button to a mass of the vibration device, the first distance representing a distance between the center of the button and the vibration fulcrum, the second distance representing a distance between a center of the vibration device and the vibration fulcrum.
4. The bone conduction speaker according to claim 1 , wherein the first ratio is not greater than a first ratio threshold.
5. The bone conduction speaker according to claim 4 , wherein the second ratio is not greater than a second ratio threshold.
6. The bone conduction speaker according to claim 1 , wherein the first ratio is not greater than a third ratio threshold.
7. The bone conduction speaker according to claim 1 , wherein the bone conduction speaker further includes a housing for accommodating the vibration device, the housing includes an outer side wall and a peripheral side wall.
8. The bone conduction speaker according to claim 7 , wherein a ratio of the third distance to a fourth distance is not be greater than a fourth ratio threshold, the third distance representing a vertical distance between a top of the button and a top end position of the outer side wall, the fourth distance representing a vertical distance between a bottom of the button and a bottom end position of the outer side wall.
9. The bone conduction speaker according to claim 7 , wherein the peripheral side wall includes a first peripheral side wall arranged along a length direction of the outer side wall, a ratio of the fifth distance to a sixth distance is not be greater than a fifth ratio threshold, the fifth distance representing a vertical distance between a top of the button and a top end position of the first peripheral side wall, the sixth distance representing a vertical distance between a bottom of the button and a bottom end position of the first peripheral side wall.
10. The bone conduction speaker according to claim 7 , wherein the bone conduction speaker further includes a connection portion connecting the ear hook and the vibration device, the connection portion has a central axis, an extension line of the central axis has a projection on a plane where the outer surface of the button locates, and an angle formed between the projection and the long axis direction of the button is less than an angle threshold.
11. 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.
12. The bone conduction speaker according to claim 11 , 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.
13. The bone conduction speaker according to claim 12 , wherein the first torus is fixed on a magnetic component.
14. The bone conduction speaker according to claim 13 , further comprising a voice coil, wherein the voice coil is driven by the magnetic component and fixed on the second torus.
15. The bone conduction speaker according to claim 14 , wherein the at least two first rods are staggered with the at least two second rods.
16. The bone conduction speaker according to claim 15 , wherein a staggered angle between one of the at least two first rods and one of the at least two second rods is 60 degrees.
17. The bone conduction speaker according to claim 14 , wherein the magnetic component comprises:
a bottom plate;
an annular magnet attaching to the bottom plate;
an inner magnet concentrically disposed inside the annular magnet;
an inner magnetic conductive plate attaching to the inner magnet;
an annular magnetic conductive plate attaching to the annular magnet; and
a grommet attaching to the annular magnetic conductive plate.
18. The bone conduction speaker according to claim 1 , wherein the vibration conductive plate is made of stainless steels and has a thickness in a range of 0.1 to 0.2 mm.
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.