PIEZOELECTRIC SENSOR AND ELECTRONIC DEVICE

The present invention provides a piezoelectric sensor and an electronic device including the piezoelectric sensor. The piezoelectric sensor includes a piezoelectric ceramic layer having a first surface and a second surface, a first metal shrapnel mounted on the first surface, and a second metal shrapnel mounted on the second surface. A first cavity is formed between the first metal shrapnel and the piezoelectric ceramic layer and a second cavity is formed between the second metal shrapnel and the piezoelectric ceramic layer. The piezoelectric sensor further includes a first damping member located in the first cavity and a second damping member located in the second cavity. The second damping member is arranged symmetrically with the first damping member. The piezoelectric sensor and electronic device of the present invention can reduce the internal stress of the piezoelectric ceramic layer, thereby improving the reliability of the piezoelectric sensor.

FIELD OF THE PRESENT INVENTION

The present invention relates to the field of sensor, and more particularly, to a piezoelectric sensor and an electronic device including the same.

DESCRIPTION OF RELATED ART

Currently, the piezoelectric ceramic transducers are used in the buttons and other components of electronic products such as mobile phones and watches on the market, to achieve the functions of sensing and vibration. And it has achieved good user experience and market response. In related art, the piezoelectric ceramic transducers mainly have an arch shape or cymbal structures. However, due to the highly brittle and poor impact resistance of the piezoelectric ceramics, the piezoelectric ceramics are easy to be broken during the dropping reliability tests. This greatly limits the application and promotion of the piezoelectric ceramic transducers. At the same time, during use, when pressing the piezoelectric ceramic transducers, because it is easy to use excessive force, the arch-shaped or cymbal-shaped sensors will be deformed excessively, which may easily cause damage to the device.

Therefore, it is desired to provide a new piezoelectric sensor and a new electronic device which can overcome the above problems.

SUMMARY

In view of the above, the embodiment of the present invention provides a new piezoelectric sensor. By the present invention, the piezoelectric sensor has high reliability.

The present invention provides a piezoelectric sensor including a piezoelectric ceramic layer. The piezoelectric ceramic layer includes a first surface and a second surface opposite to the first surface. The piezoelectric sensor further includes a first metal shrapnel mounted on the first surface and a second metal shrapnel mounted on the second surface. A first cavity is formed between the first metal shrapnel and the piezoelectric ceramic layer and a second cavity is formed between the second metal shrapnel and the piezoelectric ceramic layer. The piezoelectric sensor further includes a first damping member located in the first cavity and fixed on the first surface and a second damping member located in the second cavity and fixed on the second surface. The second damping member is arranged symmetrically with the first damping member.

As an improvement, one side of the first damping member is secured to the first surface of the piezoelectric ceramic layer, and the other side of the first damping member is abutted against the first metal shrapnel; one side of the second damping member is secured to the second surface of the piezoelectric ceramic layer, and the other side of the second damping member is abutted against the second metal shrapnel.

As an improvement, each of the first damping member and the second damping member is selected from one or more of foam, thermosetting glue, rubber, and silicone.

As an improvement, a length of the first damping member accounts for 10% to 90% of a length of the piezoelectric ceramic layer, and a length of the second damping member accounts for 10% to 90% of the length of the piezoelectric ceramic layer.

As an improvement, each of the first metal shrapnel and the second metal shrapnel includes a fixation portion fixed with the piezoelectric ceramic layer, an extension portion extending obliquely from the fixation portion in a direction away from the piezoelectric ceramic layer, and a horizontal portion extending horizontally from the extension portion.

In view of the above, the embodiment of the present invention provides a new electronic device. By the present invention, the piezoelectric sensor of the electronic device has high reliability.

The present invention provides an electronic device including a housing, a frame received in the housing, a button fixed to the housing, and a piezoelectric sensor located between the frame and the button. The piezoelectric sensor s a piezoelectric ceramic layer. The piezoelectric ceramic layer includes a first surface and a second surface opposite to the first surface. The piezoelectric sensor further includes a first metal shrapnel mounted on the first surface and a second metal shrapnel mounted on the second surface. A first cavity is formed between the first metal shrapnel and the piezoelectric ceramic layer and a second cavity is formed between the second metal shrapnel and the piezoelectric ceramic layer. The piezoelectric sensor further includes a first damping member located in the first cavity and fixed on the first surface and a second damping member located in the second cavity and fixed on the second surface. The second damping member is arranged symmetrically with the first damping member.

As an improvement, the electronic device further includes a supporting member connecting the piezoelectric sensor to the frame and a connecting member connecting the piezoelectric sensor and the button.

As an improvement, one side of the first damping member is secured to the first surface of the piezoelectric ceramic layer, and the other side of the first damping member is abutted against the first metal shrapnel; one side of the second damping member is secured to the second surface of the piezoelectric ceramic layer, and the other side of the second damping member is abutted against the second metal shrapnel.

As an improvement, each of the first damping member and the second damping member is selected from one or more of foam, thermosetting glue, rubber, and silicone.

As an improvement, a length of the first damping member accounts for 10% to 90% of a length of the piezoelectric ceramic layer, and a length of the second damping member accounts for 10% to 90% of the length of the piezoelectric ceramic layer.

As an improvement, each of the first metal shrapnel and the second metal shrapnel includes a fixation portion fixed with the piezoelectric ceramic layer, an extension portion extending obliquely from the fixation portion in a direction away from the piezoelectric ceramic layer, and a horizontal portion extending horizontally from the extension portion.

As an improvement, the fixation portion of the first metal shrapnel and the fixation portion of the second metal shrapnel are fixed with the piezoelectric ceramic layer by glue.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The present invention will hereinafter be described in detail with reference to exemplary embodiments. To make the technical problems to be solved, technical solutions and beneficial effects of the present invention more apparent, the present invention is described in further detail together with the figures and the embodiments. It should be understood the specific embodiments described hereby is only to explain the disclosure, not intended to limit the disclosure.

Referring to theFIGS.1-2, the present invention provides one embodiment of a piezoelectric sensor100. The piezoelectric sensor100includes a piezoelectric ceramic layer1, a first metal shrapnel21and a second metal shrapnel22fixed with the piezoelectric ceramic layer1, a first damping member31secured between the first metal shrapnel21and piezoelectric ceramic layer1, a second damping member32secured between the second metal shrapnel22and piezoelectric ceramic layer1, a first electrode41provided at one end of the piezoelectric ceramic layer1, and a second electrode42provided at the other end of the piezoelectric ceramic layer1.

The piezoelectric ceramic layer1includes a first surface11and a second surface12opposite to the first surface11. A first cavity51is formed between the first metal shrapnel21and the first surface11of the piezoelectric ceramic layer1. A second cavity52is formed between the second metal shrapnel22and the second surface12of the piezoelectric ceramic layer1. The first damping member31locates in the first cavity51and fixed on the first surface11of the piezoelectric ceramic layer1. The second damping member32locates in the second cavity52and fixed on the second surface12of the piezoelectric ceramic layer1. The second damping member32is arranged symmetrically with the first damping member31. Each of the first damping member31and the second damping member32is selected from one or more of foam, thermosetting glue, rubber, and silicone, and so on.

One side of the first damping member31is secured to the first surface11of the piezoelectric ceramic layer1, and the other side of the first damping member31is abutted against the first metal shrapnel21. One side of the second damping member32is secured to the second surface12of the piezoelectric ceramic layer1, and the other side of the second damping member32is abutted against the second metal shrapnel22. A length of the first damping member31accounts for 10% to 90% of a length of the piezoelectric ceramic layer1, and a length of the second damping member32accounts for 10% to 90% of the length of the piezoelectric ceramic layer.

Each of the first metal shrapnel21and the second metal shrapnel22includes a fixation portion201fixed with the piezoelectric ceramic layer1, an extension portion202extending obliquely from the fixation portion201in a direction away from the piezoelectric ceramic layer1, and a horizontal portion203extending horizontally from the extension portion202. The fixation portion201of the first metal shrapnel21and the fixation portion201of the second metal shrapnel22are fixed with the piezoelectric ceramic layer1by glue.

Both the first metal shrapnel21and the second metal shrapnel22have two fixation portions201, two extension portions202and one horizontal portion203, so that each of the first metal shrapnel21and the second metal shrapnel22has a trapezoidal shape.

The first electrode41is attached and fixed to one side surface of the piezoelectric ceramic layer1connecting the first surface11and the second surface12, and the second electrode42is attached and fixed to the other side surface of the piezoelectric ceramic layer1connecting the first surface11and the second surface12. The first electrode41and the second electrode42supply power to the piezoelectric ceramic layer1.

The piezoelectric sensor100of the present invention provides the first damping member31and the second damping member32, and the first damping member31and the second damping member32play a role in limiting and supporting the piezoelectric ceramic layer1disposed in the middle position, thereby reducing the internal stress of the piezoelectric ceramic layer and the glue. The piezoelectric sensor100of the present invention can improve its reliability. Through the test, the internal stress of the piezoelectric ceramic layer1was reduced to 70 MPa after improvement (with damping member added) from 133 MPa before (without damping member). And the internal stress of the glue was reduced to 18 Mpa after improvement (with damping member added) from 37 MPa before (without damping member). It can be seen that the performance of the piezoelectric sensor100has been significantly improved.

Referring to theFIGS.1-3, the present invention provides one embodiment of an electronic device200inFIG.3. The electronic device200includes a housing6, a cover (not shown) covering with the housing6, a frame7received in the housing6, and a button8fixed to the housing1. The electronic device200further includes the piezoelectric sensor100as described above. The piezoelectric sensor100locates between the frame7and the button8. In detail, the electronic device200further includes a supporting member91connecting the piezoelectric sensor100to the frame7and a connecting member92connecting the piezoelectric sensor100and the button8. The horizontal portion203of the first metal shrapnel21is fixedly attached to the connecting member92so that the piezoelectric sensor100can transmit a vibration to the button8. The horizontal part203of the second metal shrapnel22is fixedly attached to the supporting member91so that the frame7can support the piezoelectric sensor100.

Compared with related technologies, the present invention provides a piezoelectric sensor including a piezoelectric ceramic layer. The piezoelectric ceramic layer includes a first surface and a second surface opposite to the first surface. The piezoelectric sensor further includes a first metal shrapnel mounted on the first surface and a second metal shrapnel mounted on the second surface. A first cavity is formed between the first metal shrapnel and the piezoelectric ceramic layer and a second cavity is formed between the second metal shrapnel and the piezoelectric ceramic layer. The piezoelectric sensor further includes a first damping member located in the first cavity and fixed on the first surface and a second damping member located in the second cavity and fixed on the second surface. The second damping member is arranged symmetrically with the first damping member. The piezoelectric sensor of the present invention by setting first and second damping members, which play a role in limiting and supporting the piezoelectric ceramic layer disposed in the middle position, thereby reducing the internal stress of the piezoelectric ceramic layer and the glue. The piezoelectric sensor of the present invention improves its reliability.

Compared with related technologies, the present invention provides an electronic device including a housing, a frame received in the housing, a button fixed to the housing, and a piezoelectric sensor located between the frame and the button. The piezoelectric sensor includes a piezoelectric ceramic layer. The piezoelectric ceramic layer includes a first surface and a second surface opposite to the first surface. The piezoelectric sensor further includes a first metal shrapnel mounted on the first surface and a second metal shrapnel mounted on the second surface. A first cavity is formed between the first metal shrapnel and the piezoelectric ceramic layer and a second cavity is formed between the second metal shrapnel and the piezoelectric ceramic layer. The piezoelectric sensor further includes a first damping member located in the first cavity and fixed on the first surface and a second damping member located in the second cavity and fixed on the second surface. The second damping member is arranged symmetrically with the first damping member. The piezoelectric sensor of electronic device of the present invention by setting first and second damping members, which play a role in limiting and supporting the piezoelectric ceramic layer disposed in the middle position, thereby reducing the internal stress of the piezoelectric ceramic layer and the glue. The electronic device of the present invention improves its reliability.