Bone conduction sound transmission devices
The present disclosure is of a bone conduction sound transmission device. The bone conduction sound transmission device includes of a laminated structure and a base structure. The laminated structure is formed by a vibration unit and an acoustic transducer unit. The base structure is configured to load the laminated structure. At least one side of the laminated structure is physically connected to the base structure. The base structure vibrates based on an external vibration signal, and the vibration unit deforms in response to the vibration of the base structure; and the acoustic transducer unit generates an electrical signal based on the deformation of the vibration unit.
1 . A bone conduction sound transmission device, comprising:
a laminated structure formed by a vibration unit and an acoustic transducer unit; and
a base structure configured to load the laminated structure, and at least one side of the laminated structure being physically connected to the base structure; wherein
the base structure vibrates based on an external vibration signal, and the vibration unit deforms in response to the vibration of the base structure; and the acoustic transducer unit generates an electrical signal based on the deformation of the vibration unit, wherein
the vibration unit includes at least one support arm and a mass element, the mass element is connected to the base structure through the at least one support arm
the at least one support arm includes a first bar-shaped part and a second bar-shaped part, one end of the first bar-shaped part is connected to the mass element, an other end of the first bar-shaped part is connected to one end of the second bar-shaped part;
a length of the first bar-shaped part is within a range of 20 μm-200 μm, and a width of the first bar-shaped part is within a range of 50 μm-400 μm; or
a length of the second bar-shaped part is within a range of 500 μm-1300 μm, and a width of the second bar-shaped part is within a range of 50 μm-400 μm.
2 . The bone conduction sound transmission device of claim 1 , wherein a resonant frequency of the bone conduction sound transmission device is within a range of 1 kHz-5 KHz.
3 . The bone conduction sound transmission device of claim 1 , wherein the resonant frequency of the bone conduction sound transmission device is positively correlated with a stiffness of the vibration unit, or the resonant frequency of the bone conduction sound transmission device is negatively correlated with a mass of the laminated structure.
4 . The bone conduction sound transmission device of claim 1 , wherein the acoustic transducer unit includes a first electrode layer, a first piezoelectric layer, and a second electrode layer arranged in sequence from top to bottom, and the first electrode layer or the second electrode layer is connected to an upper surface or a lower surface of the at least one support arm.
5 . The bone conduction sound transmission device of claim 4 , wherein the acoustic transducer unit includes at least one elastic layer, and the at least one elastic layer is located on an upper surface or a lower surface of the first electrode layer or an upper surface or a lower surface of the second electrode layer.
6 . The bone conduction sound transmission device of claim 5 , wherein a thickness of the at least one elastic layer is 1 time-6 times of a thickness of the first piezoelectric layer.
7 . The bone conduction sound transmission device of claim 4 , wherein a neutral layer is formed on the bone conduction sound transmission device, and a deformation stress of the neutral layer is zero when the support arm is deformed; and the neutral layer does not overlap with the first piezoelectric layer in a thickness direction.
8 . The bone conduction sound transmission device of claim 4 , wherein an electrode insulation trench is arranged on the first electrode layer or the second electrode layer, and the electrode insulation trench is used to divide the first electrode layer or the second electrode layer into two or more electrode regions.
9 . The bone conduction sound transmission device of claim 4 , wherein an overlapping region of the first electrode layer, the first piezoelectric layer, and the second electrode layer extends toward the mass element to form an extension region, and the extension region is located on an upper surface or a lower surface of the mass element.
10 . The bone conduction sound transmission device of claim 9 , wherein a width of the extension region on a plane perpendicular to a thickness direction is 1.2 times-2 times of a width of a connection part of the at least one support arm and the mass element on a plane perpendicular to the thickness direction.
11 . The bone conduction sound transmission device of claim 1 , wherein a thickness of the mass element is within a range of 1 μm-400 μm.
12 . The bone conduction sound transmission device of claim 1 , wherein the acoustic transducer unit includes a first electrode layer, a first piezoelectric layer, and a second electrode layer, and a ratio of an area of an overlapping region of the first electrode layer, the first piezoelectric layer, and the second electrode layer to an area of a cross section of the at least one support arm perpendicular to a thickness direction is within a range of 5%-40%.
13 . The bone conduction sound transmission device of claim 1 , wherein an other end of the second bar-shaped part is connected to the base structure.
14 . The bone conduction sound transmission device of claim 1 , wherein the at least one support arm further includes a third bar-shaped part; an other end of the second bar-shaped part is connected to one end of the third bar-shaped part; and an other end of the third bar-shaped part is connected to the base structure.
15 . The bone conduction sound transmission device of claim 14 , wherein
the length of the first bar-shaped part is within a range of 20 μm-200 μm, and the width of the first bar-shaped part is within a range of 50 μm-300 μm; or
the length of the second bar-shaped part is within a range of 500 μm-1200 μm, and the width of the second bar-shaped part is within a range of 50 μm-300 μm; or
a length of the third bar-shaped part is within a range of 800 μm-1300 μm, and a width of the third bar-shaped part is within a range of 50 μm-300 μm.
16 . The bone conduction sound transmission device of claim 1 , a width of the at least one support arm is smaller than a width of an edge of the mass element connected to the at least one support arm.