Key structure, electronic equipment and method for improving drop impact resistance of piezoelectric ceramic

Abstract

The invention discloses a key structure, an electronic device and a method for improving falling impact resistance of piezoelectric ceramics, and relates to the technical field of electronic equipment.The key structure comprises a key body and a piezoelectric element, the piezoelectric element is arranged on one side of the key body and comprises a reinforcing plate and the piezoelectric ceramics, and the reinforcing plate is arranged on the other side of the key body. The reinforcing plate is provided with a first end and a second end which are opposite to each other, and the piezoelectric ceramic is fixed on any surface of the reinforcing plate or embedded in the reinforcing plate and located between the first end and the second end; the reinforcing plate is made of a material of which the loss factor is greater than 0.01, and vibration waves generated by falling impact are transmitted to the piezoelectric ceramic through the reinforcing plate so as to reduce the vibration waves transmitted to the piezoelectric ceramic; according to the technical scheme provided by the invention, the drop impact resistance of the key structure can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic equipment, and in particular to a key structure, electronic equipment and a method for improving the drop impact resistance of piezoelectric ceramics. Background Art

[0002] With the rapid development of communication technology, consumer electronic products have been widely used in our daily life, among which buttons are the most frequently used structures in electronic products. At present, the button structure usually adopts piezoelectric ceramic elements as driving components. However, due to the structural reasons of the piezoelectric ceramic element material itself, the material has low toughness, low bending strength, and is extremely impact-resistant. When subjected to a small impact, it will crack and fail, that is, the button structure has poor anti-drop impact performance. Summary of the invention

[0003] The main purpose of the present invention is to propose a key structure, an electronic device and a method for improving the drop impact resistance of piezoelectric ceramics, aiming to improve the drop impact resistance of the key structure.

[0004] In order to achieve the above object, the present invention proposes a key structure, which comprises:

[0005] Button body;

[0006] A piezoelectric element is arranged on one side of the button body, and the piezoelectric element includes a reinforcing plate and a piezoelectric ceramic. The reinforcing plate has a first end and a second end opposite to each other, and the piezoelectric ceramic is fixed on any surface of the reinforcing plate or embedded in the reinforcing plate and is located between the first end and the second end; the reinforcing plate is made of a material with a loss factor greater than 0.01, and the vibration wave generated by the drop impact is transmitted to the piezoelectric ceramic through the reinforcing plate to reduce the vibration wave transmitted to the piezoelectric ceramic.

[0007] In one embodiment, the reinforcing plate is made of at least one of a fiber material, an alloy material, a damping composite material, a plastic material, and a porous composite material.

[0008] In one embodiment, the reinforcing plate is made of fiber material and is processed, and the angle between the plate surface of the reinforcing plate and the fiber weaving direction is defined as θ, 30°≤θ≤60°.

[0009] In one embodiment, at least one surface of the reinforcing plate is provided with a shock absorbing groove, and the shock absorbing groove is provided close to an end portion of the reinforcing plate and is located outside the piezoelectric ceramic.

[0010] In one embodiment, the thickness of the portion of the reinforcing plate corresponding to the shock absorbing groove is 10-95% of the thickness of the reinforcing plate.

[0011] In one embodiment, a mounting groove is provided on one surface of the reinforcing plate, and the piezoelectric ceramic is fixed in the mounting groove.

[0012] In one embodiment, the piezoelectric element further includes a protective glue, and the protective glue is disposed on the outer peripheral wall of the piezoelectric ceramic.

[0013] In one embodiment, the button structure also includes a mounting shell and two shock-absorbing members, the mounting shell is provided with a accommodating space with at least one side opening, the piezoelectric element is located in the accommodating space, the button body is arranged on the surface of the mounting shell facing the opening, and at least partially extends into the opening and the accommodating space, and the extending portion of the button body abuts against the piezoelectric element; the two shock-absorbing members are respectively arranged at the first end and the second end, and each of the shock-absorbing members is located on the surface of the reinforcing plate opposite to the mounting shell, and is fixedly connected to the mounting shell.

[0014] In one embodiment, the shock absorbing member includes a first shock absorbing portion and a second shock absorbing portion which are bent and connected, the first shock absorbing portion is arranged on the surface of the reinforcing plate facing the button body, the second shock absorbing portion is arranged on the side of the reinforcing plate, and the first shock absorbing portion and the second shock absorbing portion are both fixed on the mounting shell.

[0015] In one embodiment, the button body includes a covering portion, an assembly portion and abutting portion which are connected in sequence, the radial dimensions of the covering portion and the abutting portion are both larger than the radial dimensions of the assembly portion, the abutting portion is located in the accommodating space and abuts against the piezoelectric element, the assembly portion is located in the opening, and the covering portion abuts against the surface of the mounting shell where the opening is provided.

[0016] In one embodiment, the key structure further includes a buffer pad, and the buffer pad is arranged on a side of the piezoelectric element facing away from the key body.

[0017] The present invention also provides an electronic device, which includes the key structure as described above.

[0018] The present invention also proposes a method for improving the drop impact resistance of piezoelectric ceramics, the method comprising:

[0019] A material with a loss factor greater than 0.01 is compounded on the piezoelectric ceramic, so that the vibration wave generated by the drop impact is transmitted to the piezoelectric ceramic through the material with a loss factor greater than 0.01, thereby reducing the vibration wave transmitted to the piezoelectric ceramic.

[0020] In one embodiment, the step of compounding a material having a loss factor greater than 0.01 on the piezoelectric ceramic includes:

[0021] A reinforcing plate made of a material with a loss factor greater than 0.01 is bonded and fixed to any surface of the piezoelectric ceramic, and the piezoelectric ceramic is located between the two ends of the reinforcing plate, or the piezoelectric ceramic is embedded in the reinforcing plate made of a material with a loss factor greater than 0.01.

[0022] In one embodiment, the material with a loss factor greater than 0.01 is the same material or a composite material of two or more materials.

[0023] The technical solution of the present invention is that the key structure includes a key body and a piezoelectric element, the piezoelectric element is arranged on one side of the key body, the piezoelectric element includes a reinforcing plate and a piezoelectric ceramic, the piezoelectric ceramic has a first end and a second end opposite to each other, the piezoelectric ceramic is fixed on any surface of the reinforcing plate and is located between the first end and the second end; the reinforcing plate is made of a material with a loss factor greater than 0.01, and the vibration wave (or vibration energy) generated by the drop impact is transmitted to the piezoelectric ceramic through the reinforcing plate to reduce the vibration wave (or vibration energy) transmitted to the piezoelectric ceramic. In the key structure provided by the present invention, the additional reinforcing plate is made of a material with a loss factor greater than 0.01 and has a certain strength. During the drop process, the vibration wave (or vibration energy) generated by the impact of the key structure will be transmitted to the piezoelectric ceramic along the reinforcing plate, which will greatly reduce the transmission of the vibration wave (or vibration energy) to the piezoelectric ceramic, thereby effectively reducing the fracture tendency of the piezoelectric ceramic during the drop impact process, that is, the key structure has good anti-drop impact performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0025] Figure 1 A structural schematic diagram of an embodiment of a key structure provided by the present invention;

[0026] Figure 2 for Figure 1 A schematic diagram of a partially exploded structure of the key structure from another perspective;

[0027] Figure 3 for Figure 2 A schematic diagram of the enlarged structure at A in the middle;

[0028] Figure 4 for Figure 1 A schematic diagram of a partial cross-sectional structure of the key structure from another perspective;

[0029] Figure 5 for Figure 4 A structural diagram of the middle reinforcement plate from another perspective;

[0030] Figure 6 for Figure 4 A schematic diagram of the structure of the middle button body from another perspective;

[0031] Figure 7 A schematic diagram of a partial explosion structure of another embodiment of the key structure provided by the present invention;

[0032] Figure 8 for Figure 7 A schematic diagram of the enlarged structure at B in the middle;

[0033] Fig. 9 for Figure 7 A schematic diagram of a partial cross-sectional structure of the key structure from another perspective;

[0034] Fig.10 FIG. 1 is a graph showing the change of loss factor with fiber angle θ in one embodiment of the present invention.

[0035] Description of Figure Numbers:

[0036] 100. Button structure; 1. Button body; 11. Covering part; 12. Assembly part; 13. Abutment part; 2. Reinforcement plate; 2a. First end; 2b. Second end; 21. Shock-absorbing groove; 22. Mounting groove; 23. Mounting hole; 3. Piezoelectric ceramic; 4. Protective glue; 5. Buffer pad; 6. Shock-absorbing member; 61. First shock-absorbing part; 62. Second shock-absorbing part; 7. Mounting shell; 71. Opening.

[0037] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0040] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0041] As a functional ceramic material, piezoelectric ceramics have positive piezoelectric effect and inverse piezoelectric effect. By using the positive piezoelectric effect of piezoelectric ceramics, positive and negative charges can be generated between the positive and negative electrodes of the piezoelectric ceramics when the piezoelectric ceramics are pressed, forming an electric field and current; by using the inverse piezoelectric effect of piezoelectric ceramics, when a certain driving waveform is applied between the positive and negative electrodes of the piezoelectric ceramics, the piezoelectric ceramics will produce deformations in different directions. By using the positive and inverse piezoelectric effects of piezoelectric ceramics, various functional devices can be designed.

[0042] Piezoelectric touch feedback utilizes both the direct piezoelectric effect and the inverse piezoelectric effect of piezoelectric ceramics. When a finger presses the piezoelectric ceramic, the piezoelectric ceramic generates an electric charge, forming an electric field and current. The electrical signal is given to the receiving driver chip. After being recognized by the driver chip, the driver chip is triggered to output a certain electrical signal waveform, which is input into the piezoelectric ceramic, driving the piezoelectric ceramic product to vibrate. The finger feels the vibration of the piezoelectric ceramic, which forms a tactile feedback action.

[0043] The pressure sensor, piezoelectric ceramics, and driver chip form a tactile feedback circuit. The pressure sensor generates a signal when the finger gently presses the pressure sensor. The signal is output to the driver chip. The driver chip outputs an electrical signal to the piezoelectric ceramics, which drives the piezoelectric ceramics to vibrate. The finger feels the vibration of the piezoelectric ceramics, which forms a tactile feedback action. The solution using the pressure sensor has the characteristics of high sensitivity, small trigger force, and short feedback time. The pressure sensor includes piezoresistive sensors, piezocalyst sensors, and elastic wave sensors.

[0044] Using the touch feedback principle of piezoelectric ceramics, a variety of new functional devices can be designed, such as new side function buttons on mobile phones, which can realize pressing and sliding functions. Long pressing, short pressing, and pressing with different forces of the pressing function can generate different electrical signals. The driver chip recognizes different electrical signals and outputs different vibration waveforms to the piezoelectric ceramics. Under the action of different driving waveforms, the piezoelectric ceramics form different vibration accelerations and displacements as well as feedback forces, which interact with the fingers. Similarly, when the finger slides the side function buttons of the mobile phone, the pressure sensor receives different sliding actions, such as fast sliding, slow sliding, strong sliding, or small force sliding, which can interact with the mobile phone software to generate a variety of flexible and changeable control and interactive actions, greatly improving the functions of the side buttons of the mobile phone and the human-computer interaction experience.

[0045] As the driving component of the side buttons of mobile phones, piezoelectric ceramics have the characteristics of low energy consumption, short feedback time, large vibration acceleration, and large feedback force. They are researched and developed by many manufacturers. However, leaded piezoelectric ceramics such as PZT and lead-free piezoelectric ceramics such as KNN have low toughness, low bending strength, high notch sensitivity, and are extremely impact-resistant due to their own material structure. They will crack and fail when subjected to a small impact, which seriously limits the application of piezoelectric ceramics in smart wearable VR, AR, smart phones, smart headphones and other electronic products. Usually, smart wearable VR, AR, smart phones, smart headphones and other electronic products need to pass a variety of mechanical impact tests such as a 1.5m marble floor drop impact test, a drum drop test, and a micro-drop test. As mobile phone buttons, they are very likely to fall and crack and fail when subjected to impact, which seriously limits their application in smart wearable VR, AR, smart phones, smart headphones and other fields.

[0046] Based on this, the drop failure mechanism of piezoelectric ceramics used in mobile phone side keys is analyzed specifically as follows: At the moment of the phone falling, there are three types of forces acting on the piezoelectric ceramics, causing the piezoelectric ceramics to be destroyed: (1) Instantaneous acceleration. During the falling process, the phone rebounds at the moment of impact with the marble floor. The action time is less than 0.01s, and its instantaneous acceleration reaches 780m / s 2, under the action of the weight of the piezoelectric ceramic itself and the gravity of the structural parts rigidly connected to it, a force is generated to act on the piezoelectric ceramic, causing the piezoelectric ceramic to produce instantaneous strain. When the instantaneous strain exceeds the strain that the piezoelectric ceramic can withstand, the piezoelectric ceramic will break; (2) Rigid impact of the key body. The key body protrudes from the side surface of the mobile phone. When the side of the mobile phone falls, the key body first touches the ground. The weight and impact force of the entire mobile phone act on the key body, causing the key body to move inward and instantly act on the piezoelectric ceramic, causing the piezoelectric ceramic product to deform due to impact, that is, the piezoelectric ceramic will crack. (3) Vibration impact on piezoelectric ceramics. When the mobile phone falls, the interaction between the ground and the mobile phone and the key body, as well as the interaction between the mobile phone frame and the piezoelectric ceramic and substrate, will generate a strong impact vibration wave. Under the action of the vibration wave, the piezoelectric ceramic and the substrate will vibrate up and down. The superposition of vibration waves will cause the piezoelectric ceramic to crack when the stress exceeds the limit that the piezoelectric ceramic can withstand.

[0047] Based on the above technical problems and drop failure mechanism, the present invention proposes a key structure 100 , aiming to improve the drop impact resistance performance of the key structure 100 .

[0048] See also Figure 1 , Figure 2 , Figure 3 , Figure 7 and Figure 8 In one embodiment of the present invention, a key structure 100 includes a key body 1 and a piezoelectric element. The piezoelectric element is arranged on one side of the key body 1. The piezoelectric element includes a reinforcing plate 2 and a piezoelectric ceramic 3. The reinforcing plate 2 has a first end 2a and a second end 2b opposite to each other. The piezoelectric ceramic 3 is fixed on any surface of the reinforcing plate 2 or embedded in the reinforcing plate 2 and is located between the first end 2a and the second end 2b. The reinforcing plate 2 is made of a material with a loss factor greater than 0.01. The vibration wave generated by the drop impact is transmitted to the piezoelectric ceramic 3 through the reinforcing plate 2 to reduce the vibration wave transmitted to the piezoelectric ceramic 3.

[0049] Specifically, the reinforcing plate 2 is roughly in the shape of a rectangular parallelepiped plate, and has a first end 2a and a second end 2b opposite to each other along its length direction. The reinforcing plate 2 is made of a material with a loss factor greater than 0.01. The vibration wave (or vibration energy) generated by the drop impact can be transmitted to the piezoelectric ceramic 3 through the reinforcing plate 2, which greatly reduces the transmission of the vibration wave (or vibration energy) to the piezoelectric ceramic 3. The piezoelectric ceramic 3 is roughly in the shape of a sheet, and its length dimension is smaller than the length dimension of the reinforcing plate 2, so that the piezoelectric ceramic 3 is located in the middle area of ​​the reinforcing plate 2. The piezoelectric ceramic 3 can be arranged on the surface of the reinforcing plate 2 facing away from the key body 1, that is, the key body 1, the reinforcing plate 2 and the piezoelectric ceramic 3 are stacked in sequence, and the key structure 100 is a positive structure. Alternatively, the piezoelectric ceramic 3 is arranged between the reinforcing plate 2 and the key body 1, that is, the key body 1, the piezoelectric ceramic 3 and the reinforcing plate 2 are stacked in sequence, and the key structure 100 is a reverse structure. The piezoelectric ceramic 3 may be glued and fixed on the surface of the reinforcing plate 2, and the piezoelectric ceramic 3 is located between the first end 2a and the second end 2b, that is, the piezoelectric ceramic 3 is fixed in the middle area of ​​the reinforcing plate 2. Of course, the piezoelectric ceramic 3 may also be embedded in the reinforcing plate 2, and the piezoelectric ceramic 3 may be embedded in the reinforcing plate 2 by injection molding. In this way, the vibration energy generated by the external impact may also be transmitted through the reinforcing plate 2, thereby greatly reducing the transmission of the vibration energy to the piezoelectric ceramic 3.

[0050] As a vibration component, the piezoelectric ceramic 3 will expand and contract in the length direction when subjected to a driving waveform. Due to the fixed constraint of the reinforcing plate 2, the piezoelectric ceramic 3 and the reinforcing plate 2 will deform in the direction of the reinforcing plate 2, generating continuous vibration, which is transmitted to the key body 1, achieving a vibration feedback effect. The reinforcing plate 2 serves as a structural strength reinforcing plate for the piezoelectric ceramic 3. During the falling process of the key structure 100, the reinforcing plate 2 can enhance the structural strength and bending strength of the overall structure, thereby enhancing the anti-fall ability during the falling process and reducing the risk of fracture of the piezoelectric ceramic 3. In addition, through the adhesive connection between the reinforcing plate 2 and the piezoelectric ceramic 3, a vibration coupling structure is formed, which converts the expansion and contraction deformation of the piezoelectric ceramic 3 in the length direction into vibration in the thickness direction toward the reinforcing plate 2, thereby transmitting the vibration energy. At the same time, the reinforcing plate 2 is made of a material with a loss factor greater than 0.01 and has a certain structural strength. After the reinforcing plate 2 is combined with the piezoelectric ceramic 3, the vibration energy generated by the drop impact can be transmitted to the piezoelectric ceramic 3 through the reinforcing plate 2. The vibration energy is absorbed by the reinforcing plate 2 during the transmission process, thereby achieving the purpose of reducing the transmission of vibration energy to the piezoelectric ceramic 3, thereby reducing the fracture tendency of the piezoelectric ceramic 3.

[0051] Compared with the existing reinforcement plate made of metal plate, the reinforcement plate 2 is made of material with a loss factor greater than 0.01, which can more effectively reduce the transmission of vibration energy generated by the drop impact to the piezoelectric ceramic 3, thereby more effectively reducing the fracture tendency of the piezoelectric ceramic 3 during the drop impact process, and the key structure 100 has better drop impact resistance.

[0052] In the key structure 100 provided by the present invention, the additional reinforcement plate 2 is made of a material with a loss factor greater than 0.01 and has a certain strength. During the falling process, the vibration wave (or vibration energy) generated by the impact of the key structure 100 will be transmitted to the piezoelectric ceramic 3 along the reinforcement plate 2, which will greatly reduce the transmission of the vibration wave (or vibration energy) to the piezoelectric ceramic 3, thereby effectively reducing the fracture tendency of the piezoelectric ceramic 3 during the falling impact process, that is, the key structure 100 has good anti-drop impact performance.

[0053] In an optional embodiment of the present invention, the material of the reinforcing plate 2 is at least one of a fiber material, an alloy material, a damping composite material, a plastic material, and a porous composite material. Among them, the fiber material can be selected from epoxy glass fiber, carbon fiber, asbestos fiber or other high-damping fiber materials; the alloy material can be selected from copper-zinc-aluminum alloy, iron-chromium-molybdenum alloy, manganese-copper series alloy, magnesium alloy or other high-damping alloy materials; the damping composite material can be selected from rubber metal composite material, rubber fiber composite material or other high-damping composite material; the plastic material can be selected from polyacrylate, polyurethane, polyvinyl butyral or other high-damping plastic materials, and the porous composite material can be selected from foam metal or other high-damping porous composite materials. In practical applications, the reinforcing plate 2 can be selected from one or more of the above materials.

[0054] Please refer to Fig.10 In one embodiment of the present invention, the reinforcing plate 2 is made of fiber materials such as epoxy glass fiber and carbon fiber, and the angle between the plate surface of the reinforcing plate 2 and the fiber weaving direction (i.e., the fiber angle) is defined as θ. Fig.10 It can be seen that as the fiber angle θ increases, the loss factor first increases and then decreases. Fig. 9 , the selectable value range of θ is: 30°≤θ≤60°, for example, θ is 30°, 40°, 50°, 60° and the interval value between any two end points. The reinforcing plate 2 manufactured in this way has a higher loss factor, so that the fracture tendency of the piezoelectric ceramic 3 during the drop impact process can be more effectively reduced, and the key structure 100 has better drop impact resistance.

[0055] It should be noted that Fig.10 Among them, the Adams-Bacon method and the Ni-Adams method are commonly used theoretical prediction models to test the damping performance (such as loss factor) of damping materials.

[0056] See also Figure 3 , Figure 4 and Figure 5 In one embodiment of the present invention, a shock absorbing groove 21 is provided on at least one surface of the reinforcing plate 2 . The shock absorbing groove 21 is provided near the end of the reinforcing plate 2 and is located on the outer side of the piezoelectric ceramic 3 .

[0057] Specifically, the shock absorbing groove 21 can be provided on the surface of the reinforcing plate 2 facing the key body 1, or on the surface of the reinforcing plate 2 facing away from the key body 1. The shock absorbing groove 21 can optionally penetrate the two opposite side surfaces of the reinforcing plate 2. The shape of the shock absorbing groove 21 can be selected as a square groove, a U-shaped groove or other reasonable shapes, which are not limited here. The shock absorbing groove 21 is provided at the first end 2a or the second end 2b. The setting of the shock absorbing groove 21 can make the deformation of the reinforcing plate 2 during the drop impact process concentrated locally, that is, the impact deformation of the key structure 100 is concentrated to the shock absorbing groove 21, effectively reducing the strain of the contact part with the piezoelectric ceramic 3, thereby effectively reducing the risk of fracture of the piezoelectric ceramic 3; the shock absorbing groove 21 can also prevent the vibration energy from being transmitted from the end of the reinforcing plate 2 to the middle part and the piezoelectric ceramic 3, further reducing the risk of fracture of the piezoelectric ceramic 3, and improving the anti-drop ability of the key structure 100.

[0058] Of course, in order to more effectively improve the anti-drop ability of the button structure 100, the number of shock-absorbing grooves 21 can be optionally set to two, and the two shock-absorbing grooves 21 are respectively opened at the first end 2a and the second end 2b. The two shock-absorbing grooves 21 can be opened on the same surface of the reinforcement plate 2, or on different surfaces of the reinforcement plate 2, which is not limited here.

[0059] In an optional embodiment of the present invention, the thickness of the portion of the reinforcing plate 2 corresponding to the damping groove 21 is 10-95% (e.g., 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 85% and any interval between the two end points) of the thickness of the reinforcing plate 2. Such a design can effectively reduce the risk of fracture of the piezoelectric ceramic 3 while ensuring the overall structural strength of the reinforcing plate 2.

[0060] Please refer to Figure 4 , Figure 8 and Fig. 9 In some embodiments of the present invention, a mounting groove 22 is provided on one surface of the reinforcing plate 2 , and the piezoelectric ceramic 3 is fixed in the mounting groove 22 .

[0061] like Figures 3 to 5As shown, in one embodiment of the present invention, the key structure 100 is a positive structure, that is, the piezoelectric ceramic 3 is arranged on the side of the reinforcing plate 2 facing away from the key body 1, and a mounting groove 22 is provided on the surface of the reinforcing plate 2 facing away from the key body 1. The size of the mounting groove 22 is adapted to the size of the piezoelectric ceramic 3, and the piezoelectric ceramic 3 is glued and fixed in the mounting groove 22. In this way, the combination of the piezoelectric ceramic 3 and the reinforcing plate 2 is more firm and the operation is more convenient.

[0062] like Figure 8 and Fig. 9 As shown, in one embodiment of the present invention, the key structure 100 is a reverse-mounted structure, that is, the piezoelectric ceramic 3 is arranged on the side of the reinforcing plate 2 facing the key body 1, and a mounting groove 22 is opened on the surface of the reinforcing plate 2 facing the key body 1. The size of the mounting groove 22 is adapted to the size of the piezoelectric ceramic 3, and the piezoelectric ceramic 3 is glued and fixed in the mounting groove 22. In this way, the combination of the piezoelectric ceramic 3 and the reinforcing plate 2 is more firm and the operation is more convenient.

[0063] Optionally, the piezoelectric ceramic 3 has a length of 10-30 mm, a width of 2-5 mm, and a thickness of 0.2-0.9 mm, and the mounting groove 22 is also in the shape of a rectangular parallelepiped, the size of which must match the size of the piezoelectric ceramic 3 to ensure that the piezoelectric ceramic 3 can be fixed in the mounting groove 22 .

[0064] Please refer to Figure 3 , Figure 4 , Figure 8 and Fig. 9 In one embodiment of the present invention, the piezoelectric element further includes a protective glue 4, which is arranged on the outer peripheral wall of the piezoelectric ceramic 3. The protective glue 4 can not only fix the piezoelectric ceramic 3 to prevent the local crack from expanding, but also prevent the relative movement between the piezoelectric ceramic 3 and the reinforcing plate 2 during the falling process, thereby protecting the piezoelectric ceramic 3.

[0065] It should be noted that in the embodiment where the mounting groove 22 is provided on the surface of the reinforcing plate 2, the size of the mounting groove 22 is larger than the size of the piezoelectric ceramic 3 to ensure that the protective glue 4 is also located in the mounting groove 22, so that the structure is more compact and more secure.

[0066] In some embodiments of the present invention, the protective glue 4 is an integrated annular structure, and the protective glue 4 is arranged around the outer peripheral wall of the piezoelectric ceramic 3 , so that the piezoelectric ceramic 3 can be fixed and protected more effectively.

[0067] Of course, in other embodiments of the present invention, the protective glue 4 may also be a split structure, that is, it includes a plurality of protective glue 4 segments, and the plurality of protective glue 4 segments are arranged at intervals along the circumferential direction of the piezoelectric ceramic 3 on the outer peripheral wall of the piezoelectric ceramic 3. In this way, the piezoelectric ceramic 3 can be fixed and protected more effectively, and the production of the protective glue 4 is convenient, and piezoelectric ceramics 3 of different sizes can be fixed and protected.

[0068] Optionally, the thickness of the protective glue 4 is 0.05-1 mm (such as 0.05 mm, 0.1 mm, 0.2 mm, 0.5 mm, 0.8 mm, 1 mm and any interval between the two end points). The protective glue 4 in the above thickness range can more effectively fix and protect the piezoelectric ceramic 3.

[0069] See also Figures 2 to 4 In one embodiment of the present invention, the key structure 100 also includes a mounting shell 7 and two shock absorbing members 6. The mounting shell 7 is provided with a receiving space with at least one side opening 71. The piezoelectric element is located in the receiving space. The key body 1 is provided on the surface of the mounting shell 7 facing the opening 71 and at least partially extends into the opening 71 and the receiving space. The extending portion of the key body 1 abuts against the piezoelectric element. The two shock absorbing members 6 are respectively provided at the first end 2a and the second end 2b, and each shock absorbing member 6 is located on the surface of the reinforcing plate 2 opposite to the mounting shell 7 and is fixedly connected to the mounting shell 7.

[0070] Specifically, the mounting shell 7 is a part of an electronic device, such as a mobile phone frame, a tablet frame, or other structural parts, which is convenient for user operation. The specific structure of the mounting shell 7 is not limited. The material of the mounting shell 7 can be plastic, or it can be a metal material such as stainless steel, aluminum alloy, titanium alloy, etc., which is not limited here. The interior of the mounting shell 7 defines a accommodating space, which is used to place structures such as piezoelectric ceramics 3, reinforcement plates 2, protective glue, shock absorbers 6, and key bodies 1, which are used to cooperate to realize the pressing function of the key structure 100. The accommodating space runs through one side of the mounting shell 7 to form an opening 71. A part of the key body 1 is located in the opening 71. Optionally, the surface of the key body away from the reinforcement plate 2 is flush with the opening 71 or exposed to the opening 71 to form a pressable area for the user to press. The connection method of the piezoelectric ceramics 3, reinforcement plates 2, protective glue, key bodies 1, shock absorbers 6 and other structures with the mounting shell 7 can be selected as adhesive connection, card connection or other reasonable methods, which are not limited here. The shock absorbing member 6 is located between the reinforcing plate 2 and the mounting shell 7, and is respectively located at the first end 2a and the second end 2b. Such a setting can play a role in shock absorption and buffering. At the same time, the two shock absorbing members 6 can play a role in pre-tightening and fixing the two ends of the reinforcing plate 2 (i.e., the first end 2a and the second end 2b).

[0071] Optionally, the shock absorbing member 6 is made of foam, silicone, rubber, elastic material, bent metal sheet or other reasonable materials.

[0072] Please again Figure 3 and Figure 4In some embodiments of the present invention, the shock absorbing member 6 includes a first shock absorbing portion 61 and a second shock absorbing portion 62 which are bent and connected. The first shock absorbing portion 61 is arranged on the surface of the reinforcing plate 2 facing the key body 1, and the second shock absorbing portion 62 is arranged on the side of the reinforcing plate 2. The first shock absorbing portion 61 and the second shock absorbing portion 62 are both fixed on the mounting shell 7.

[0073] Specifically, the first shock absorbing portion 61 and the second shock absorbing portion 62 are L-shaped structures, wherein the first shock absorbing portion 61 is arranged between the end surface of the reinforcing plate 2 and the inner wall surface of the mounting shell 7, and the second shock absorbing portion 62 is arranged between the end surface of the reinforcing plate 2 and the inner wall surface of the mounting shell 7, and the first shock absorbing portion 61 and the second shock absorbing portion 62 are both fixed on the mounting shell 7, and the fixing method thereof can be selected to be gluing, which is simple to operate and relatively firmly fixed. With such a setting, the surface and end surface of the reinforcing plate 2 facing the key body 1 are not in contact with the mounting shell 7, so that when the reinforcing plate 2 falls along the length direction and the thickness direction, the first shock absorbing portion 61 and the second shock absorbing portion 62 can play a better shock absorbing and buffering role, and can also play a role in pre-tightening and fixing the two ends of the reinforcing plate 2.

[0074] like Figure 3 and Figure 4 In some embodiments of the present invention, the first end 2a and the second end 2b of the reinforcing plate 2 are both provided with mounting holes 23, and the mounting shell 7 is correspondingly provided with matching holes. The reinforcing plate 2 is fixed in the mounting shell 7 by the cooperation of the fasteners with the mounting holes 23 and the matching holes. Optionally, the fasteners are screws and the matching holes are threaded holes. Such a structure is more firmly fixed and is more convenient to operate.

[0075] Please refer to Figure 6 In one embodiment of the present invention, the key body 1 includes a covering portion 11, an assembly portion 12 and abutting portion 13 which are connected in sequence. The radial dimensions of the covering portion 11 and the abutting portion 13 are both larger than the radial dimensions of the assembly portion 12. The abutting portion 13 is located in the accommodating space and abuts against the piezoelectric element. The assembly portion 12 is located in the opening 71, and the covering portion 11 abuts against the surface of the mounting shell 7 where the opening 71 is provided.

[0076] Specifically, the key body 1 is roughly in an I-shape, that is, the radial dimensions of the covering portion 11 and the abutting portion 13 are both larger than the radial dimensions of the assembly portion 12, wherein the specific shapes and dimensions of the covering portion 11, the assembly portion 12 and the abutting portion 13 are not limited, as long as the assembly portion 12 is located in the opening 71, the covering portion 11 covers the opening 71, and the abutting portion 13 is located in the accommodating space, the key body 1 can be blocked from moving inward by the mounting shell 7 and the key body 1, and can also be blocked from moving outward by the mounting shell 7 and the key body 1, which can effectively reduce the impact of the key body 1 on the internal structure of the piezoelectric ceramic 3 and enhance the impact resistance of the piezoelectric ceramic 3.

[0077] Optionally, in order to ensure that the key body 1 has good overall firmness, the covering portion 11 , the assembly portion 12 and the abutting portion 13 adopt an integrated structure.

[0078] Please refer to Figure 3 , Figure 4 , Figure 8 and Fig. 9 In some embodiments of the present invention, the key structure 100 further includes a buffer pad 5 , which is disposed in the accommodating space and located on a side of the piezoelectric element facing away from the key body 1 .

[0079] Specifically, when the key structure 100 is installed upright, the buffer pad 5 is located on the side of the piezoelectric ceramic 3 that is away from the reinforcing plate 2, that is, the key body 1, the reinforcing plate 2, the piezoelectric ceramic 3 and the buffer pad 5 are sequentially stacked in the accommodating space. When the key structure 100 is installed reversely, the buffer pad 5 is located on the side of the reinforcing plate 2 that is away from the piezoelectric ceramic 3, that is, the key body 1, the piezoelectric ceramic 3, the reinforcing plate 2 and the buffer pad 5 are sequentially stacked in the accommodating space. During the falling process, the key body 1 will move toward the accommodating cavity, and the setting of the buffer pad 5 can play a buffering role to further reduce the risk of the piezoelectric ceramic 3 breaking.

[0080] Optionally, the material of the buffer pad 5 can be selected as soft materials such as foam, silicone, double-sided tape, etc., and the thickness of the buffer pad 5 can be selected as 0.1-2mm (such as 0.1mm, 0.5mm, 1.5mm, 2mm and an interval value between any two end points).

[0081] It should be noted that, when the key structure 100 is properly installed, in order to ensure that the buffer pad 5 has a better buffering effect, the surface size of the buffer pad 5 is required to be larger than the surface size of the piezoelectric ceramic 3, that is, the projection of the piezoelectric ceramic 3 on the plane where the buffer pad 5 is located is within the outer contour of the buffer pad 5. In this way, the entire surface of the piezoelectric ceramic 3 is in contact with the buffer pad 5, which can better buffer and protect the piezoelectric ceramic 3.

[0082] In some embodiments of the present invention, the button structure 100 also includes a pressure sensor, which can be set as one pressure sensor, and one pressure sensor can be optionally glued and fixed to any surface of the first end 2a or any surface of the second end 2b; of course, in order to improve the sensitivity of the button structure 100, the pressure sensor can also be set as two, and the two pressure sensors are respectively glued and fixed to any surface of the first end 2a and any surface of the second end 2b.

[0083] It should be noted that the pressure sensor and the piezoelectric ceramic 3 are both electrically connected to the control unit. The pressure sensor generates an electrical signal after receiving the pressure from the key body 1, and transmits the electrical signal to the control unit. After receiving the electrical signal, the control unit outputs a signal to realize the key response function, and outputs a pulse signal to the piezoelectric ceramic 3. Under the action of the inverse piezoelectric effect, the piezoelectric ceramic 3 generates vibration and transmits it to the key body 1, so that the key body 1 vibrates to achieve a vibration feedback effect. Among them, the control unit can be selected as a driver chip in an electronic device, and the driver chip is electrically connected to the pressure sensor and the piezoelectric element through connecting wires.

[0084] The present invention also provides an electronic device, which includes a key structure 100. The specific structure of the key structure 100 refers to the above embodiment. Since the electronic device adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here. Among them, the electronic device includes but is not limited to smart phones, tablet computers, personal computers, laptops, smart watches, wearable devices, digital cameras, video cameras, game consoles, audio, video playback devices and smart home devices.

[0085] Furthermore, the present invention also provides a method for improving the drop impact resistance of piezoelectric ceramics, the method comprising:

[0086] A material with a loss factor greater than 0.01 is compounded on the piezoelectric ceramic 3 so that the vibration wave generated by the drop impact is transmitted to the piezoelectric ceramic 3 through the material with a loss factor greater than 0.01, thereby reducing the vibration wave transmitted to the piezoelectric ceramic 3.

[0087] The method provided by the present invention uses a material with a loss factor greater than 0.01 to reduce the vibration wave (i.e., vibration energy) transmitted to the piezoelectric ceramic during the falling process, thereby effectively reducing the risk of fracture of the piezoelectric ceramic 3. The method is relatively effective and relatively simple to operate. The method for improving the drop impact resistance of piezoelectric ceramics provided by the present invention can be applied to the key structure 100 of the above-mentioned electronic device, and of course, it can also be applied to other functional devices including piezoelectric ceramics 3.

[0088] In some embodiments of the present invention, the step of compounding a material having a loss factor greater than 0.01 on the piezoelectric ceramic includes:

[0089] A reinforcing plate 2 made of a material with a loss factor greater than 0.01 is bonded and fixed to any surface of the piezoelectric ceramic 3 , and the piezoelectric ceramic 3 is located between two ends of the reinforcing plate 2 .

[0090] Specifically, a reinforcing plate 2 is first made of a material with a loss factor greater than 0.01, and the processing and manufacturing method is not limited. Then, the reinforcing plate 2 is bonded and fixed to any surface of the piezoelectric ceramic 3, and the piezoelectric ceramic 3 is located between the first end 2a and the second end 2b of the reinforcing plate 2. In this way, the vibration wave generated by the drop impact is transmitted to the piezoelectric ceramic 3 through the reinforcing plate 2 made of a material with a loss factor greater than 0.01. This can effectively reduce the vibration wave (i.e., vibration energy) transmitted to the piezoelectric ceramic 3, thereby effectively improving the drop impact resistance of the piezoelectric ceramic 3, and the method is relatively simple to operate. Among them, the specific structural settings of the piezoelectric ceramic 3 and the reinforcing plate 2 can refer to the above embodiments, and will not be repeated here.

[0091] In some other embodiments of the present invention, the step of compounding a material having a loss factor greater than 0.01 on the piezoelectric ceramic includes:

[0092] The piezoelectric ceramics are embedded in a reinforcing plate made of a material with a loss factor greater than 0.01.

[0093] Specifically, the piezoelectric ceramic 3 can be embedded in a material with a loss factor greater than 0.01 by injection molding to form a reinforcing plate 2. In this way, the material with a loss factor greater than 0.01 can completely cover the piezoelectric ceramic 3. This can also effectively reduce the vibration wave (that is, vibration energy) transmitted to the piezoelectric ceramic 3, thereby effectively improving the drop impact resistance of the piezoelectric ceramic 3. Moreover, this method is relatively simple to operate.

[0094] In some embodiments of the present invention, the material with a loss factor greater than 0.01 composited on the piezoelectric ceramic can be the same material or a composite of two or more materials, which is not limited here and is within the protection scope of the present invention. Among them, the selection of materials with a loss factor greater than 0.01 can refer to the above embodiments and will not be repeated here. When the material with a loss factor greater than 0.01 is composited with two or more materials, the composite method can be doping composite, segmented composite, or other reasonable composite methods between materials, which is not limited here.

[0095] It should be noted that the specific structure of the reinforcing plate 2 made of a material with a loss factor greater than 0.01 can be referred to the above embodiment, and will not be described in detail here.

[0096] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A key structure, characterized in that: The key structure comprises: Button body; A piezoelectric element is arranged on one side of the key body, the piezoelectric element comprises a reinforcing plate and a piezoelectric ceramic, the reinforcing plate has a first end and a second end opposite to each other, the piezoelectric ceramic is fixed on any surface of the reinforcing plate or embedded in the reinforcing plate and is located between the first end and the second end; The reinforcing plate is made of a material with a loss factor greater than 0.01, and the vibration wave generated by the drop impact is transmitted to the piezoelectric ceramic through the reinforcing plate to reduce the vibration wave transmitted to the piezoelectric ceramic.

2. The key structure according to claim 1, characterized in that: The reinforcing plate is made of at least one of a fiber material, an alloy material, a damping composite material, a plastic material, and a porous composite material.

3. The key structure according to claim 2, characterized in that: The reinforcing plate is made of fiber material and processed, and the angle between the plate surface of the reinforcing plate and the fiber weaving direction is defined as θ, 30°≤θ≤60°.

4. The key structure according to claim 1, characterized in that: At least one surface of the reinforcing plate is provided with a shock absorbing groove, and the shock absorbing groove is provided close to the end of the reinforcing plate and is located outside the piezoelectric ceramic.

5. The key structure according to claim 4, characterized in that: The thickness of the reinforcing plate corresponding to the shock absorbing groove is 10-95% of the thickness of the reinforcing plate.

6. The key structure according to claim 1, characterized in that: A mounting groove is provided on one surface of the reinforcing plate, and the piezoelectric ceramic is fixed in the mounting groove.

7. The key structure according to any one of claims 1 to 6, characterized in that: The piezoelectric element further includes a protective glue, which is arranged on the outer peripheral wall of the piezoelectric ceramic.

8. The key structure according to any one of claims 1 to 6, characterized in that: The key structure further includes a mounting shell and two shock absorbing members, the mounting shell is provided with a receiving space with at least one side opening, the piezoelectric element is located in the receiving space, the key body is provided on a surface of the mounting shell facing the opening, and at least partially extends into the opening and the receiving space, and the extending portion of the key body abuts against the piezoelectric element; The two shock absorbing members are respectively arranged at the first end and the second end, and each of the shock absorbing members is located on a surface of the reinforcing plate opposite to the mounting shell, and is fixedly connected to the mounting shell.

9. The key structure according to claim 8, characterized in that: The shock absorbing member includes a first shock absorbing portion and a second shock absorbing portion which are bent and connected, the first shock absorbing portion is arranged on the surface of the reinforcing plate facing the button body, the second shock absorbing portion is arranged on the side of the reinforcing plate, and the first shock absorbing portion and the second shock absorbing portion are both fixed on the mounting shell.

10. The key structure according to claim 8, characterized in that: The button body includes a covering portion, an assembly portion and abutting portion which are connected in sequence, the radial dimensions of the covering portion and the abutting portion are both larger than the radial dimension of the assembly portion, the abutting portion is located in the accommodating space and abuts against the piezoelectric element, the assembly portion is located in the opening, and the covering portion abuts against the surface of the mounting shell where the opening is provided.

11. The key structure according to any one of claims 1 to 6, characterized in that: The key structure further includes a buffer pad, which is arranged on a side of the piezoelectric element facing away from the key body.

12. An electronic device, characterized in that: The electronic device comprises the key structure according to any one of claims 1 to 11.

13. A method for improving the drop impact resistance of piezoelectric ceramics, characterized in that: The method comprises: A material with a loss factor greater than 0.01 is compounded on the piezoelectric ceramic, so that the vibration wave generated by the drop impact is transmitted to the piezoelectric ceramic through the material with a loss factor greater than 0.01, thereby reducing the vibration wave transmitted to the piezoelectric ceramic.

14. The method for improving the drop impact resistance of piezoelectric ceramics according to claim 13, characterized in that: The step of compounding a material having a loss factor greater than 0.01 on a piezoelectric ceramic comprises: A reinforcing plate made of a material with a loss factor greater than 0.01 is bonded and fixed to any surface of the piezoelectric ceramic, and the piezoelectric ceramic is located between the two ends of the reinforcing plate, or, The piezoelectric ceramics are embedded in a reinforcing plate made of a material with a loss factor greater than 0.

01.

15. The method for improving the drop impact resistance of piezoelectric ceramics according to claim 13, characterized in that: The material with a loss factor greater than 0.01 is the same material or a composite material of two or more materials.

Images