Piezoelectric sensor, method of manufacturing the same, and haptic feedback device

Abstract

The present disclosure provides a piezoelectric sensor, a manufacturing method thereof and a haptic feedback device, wherein the piezoelectric sensor comprises a substrate, and a first electrode layer, a piezoelectric film layer, an insulating layer and a second electrode layer arranged in sequence away from the substrate, wherein the insulating layer is in contact with at least part of the piezoelectric film layer. The piezoelectric sensor avoids short circuit and improves product yield.

Description

Technical Field

[0001] This disclosure relates to the field of sensor technology, and in particular to a piezoelectric sensor, its manufacturing method, and a tactile feedback device. Background Technology

[0002] Haptics is a key area of ​​technological development today. Specifically, haptic feedback enables interaction between a device and the human body through touch. Haptic feedback can be divided into two categories: vibration feedback and haptic reproduction technology. Summary of the Invention

[0003] This disclosure provides a piezoelectric sensor, its manufacturing method, and a tactile feedback device, the specific solutions of which are as follows:

[0004] This disclosure provides a piezoelectric sensor, comprising:

[0005] A substrate, and a first electrode layer, a piezoelectric thin film layer, an insulating layer, and a second electrode layer disposed sequentially away from the substrate, wherein the insulating layer is in at least partial contact with the piezoelectric thin film layer.

[0006] Optionally, in an embodiment of this disclosure, the side of the piezoelectric thin film layer facing away from the substrate includes at least one hollow structure, and each hollow structure is filled with the insulating layer.

[0007] Optionally, in an embodiment of this disclosure, the orthographic projection of the insulating layer on the substrate falls entirely within the region of the orthographic projection of the piezoelectric thin film layer on the substrate.

[0008] The orthographic projection of the insulating layer on the substrate overlaps with the orthographic projection of the piezoelectric thin film layer on the substrate.

[0009] Optionally, in embodiments of this disclosure, the insulating layer includes at least one of polyimide, silicon dioxide, and aluminum oxide.

[0010] Optionally, in this embodiment of the disclosure, the thickness relationship between the insulating layer and the piezoelectric thin film layer must satisfy the following equation:

[0011] d PI ≤0.1 d PZT ;

[0012] Where, d PI d represents the thickness of the insulating layer. PZT This indicates the thickness of the piezoelectric thin film layer.

[0013] Optionally, in this embodiment of the disclosure, the thickness of the insulating layer ranges from [50nm, 200nm].

[0014] Optionally, in this embodiment of the disclosure, the thickness of the piezoelectric thin film layer ranges from 0 to 2 μm.

[0015] Optionally, in this embodiment of the disclosure, the capacitance relationship between the piezoelectric thin film layer and the insulating layer must satisfy the following equation:

[0016] C PZT ≥100C PI ;

[0017] Among them, C PZT C represents the capacitance of the piezoelectric thin film layer. PI This indicates the capacitance of the insulating layer.

[0018] Optionally, in this embodiment of the disclosure, the resistance relationship between the piezoelectric thin film layer and the insulating layer must satisfy the following equation:

[0019] R PI ≥1000R PZT ;

[0020] Among them, R PZT R represents the resistance of the piezoelectric thin film layer. PI This indicates the resistance of the insulating layer.

[0021] Optionally, in an embodiment of this disclosure, a hydrophilic material layer is disposed on the side of the piezoelectric thin film layer facing away from the substrate.

[0022] Optionally, in embodiments of this disclosure, the piezoelectric thin film layer includes at least one of aluminum nitride, zinc oxide, lead zirconate titanate, barium titanate, lead titanate, potassium niobate, lithium niobate, lithium tantalate, and lanthanum gallium silicate.

[0023] Optionally, in an embodiment of this disclosure, the first electrode layer has a plurality of first columnar structures on the side near the piezoelectric thin film layer.

[0024] Optionally, in an embodiment of this disclosure, the second electrode layer has a plurality of second columnar structures on the side near the piezoelectric thin film layer.

[0025] Optionally, in this embodiment of the present disclosure, the first electrode layer has a plurality of third columnar structures on the side near the piezoelectric thin film layer, and the second electrode layer has a plurality of fourth columnar structures on the side near the piezoelectric thin film layer, wherein the orthographic projection of any third columnar structure on the substrate and the orthographic projection of any fourth columnar structure on the substrate do not overlap.

[0026] Accordingly, this disclosure provides a haptic feedback device, comprising a haptic feedback circuit and a piezoelectric sensor as described in any of the preceding embodiments; wherein:

[0027] The tactile feedback circuit is located on the side of the second electrode layer away from the first electrode layer, or on the side of the first electrode layer away from the second electrode layer. The tactile feedback circuit is used to generate voltage pulses according to the received instructions to make the structure vibrate.

[0028] Accordingly, this disclosure provides a method for manufacturing a piezoelectric sensor, comprising:

[0029] A first electrode layer is formed on a substrate.

[0030] A piezoelectric thin film layer is formed on the side of the first electrode layer that is away from the substrate.

[0031] An insulating layer is formed on the side of the piezoelectric thin film layer opposite to the first electrode layer, which is in at least partial contact with the piezoelectric thin film layer;

[0032] A second electrode layer is formed on the side of the insulating layer opposite to the piezoelectric thin film layer.

[0033] Optionally, in an embodiment of this disclosure, forming an insulating layer that at least partially contacts the piezoelectric thin film layer on the side of the piezoelectric thin film layer opposite to the first electrode layer includes:

[0034] A wet process is used to coat the piezoelectric thin film layer with polyimide material on the side opposite to the first electrode layer;

[0035] The polyimide material is cured at high temperature to form an insulating layer that is at least partially in contact with the piezoelectric film layer on the side of the piezoelectric film layer away from the first electrode layer. Attached Figure Description

[0036] Figure 1 This is a top view of a thin-film vibrating chip with cracks in the piezoelectric layer, as described in related technologies.

[0037] Figure 2 This is a schematic diagram of one structure of a piezoelectric sensor provided in an embodiment of this disclosure;

[0038] Figure 3 This is a schematic diagram of one structure of a piezoelectric sensor provided in an embodiment of this disclosure;

[0039] Figure 4 This is a schematic diagram of one structure of a piezoelectric sensor provided in an embodiment of this disclosure;

[0040] Figure 5 This is a schematic diagram of one structure of a piezoelectric sensor provided in an embodiment of this disclosure;

[0041] Figure 6 This is a schematic diagram of one structure of a piezoelectric sensor provided in an embodiment of this disclosure;

[0042] Figure 7 This is a schematic diagram of one structure of a piezoelectric sensor provided in an embodiment of this disclosure;

[0043] Figure 8 This is a schematic diagram of one structure of a piezoelectric sensor provided in an embodiment of this disclosure;

[0044] Figure 9 This is a schematic diagram of one structure of a piezoelectric sensor provided in an embodiment of this disclosure;

[0045] Figure 10 This is a schematic diagram of one structure of a haptic feedback device provided in an embodiment of the present disclosure;

[0046] Figure 11 A flowchart illustrating a method for fabricating a piezoelectric sensor according to an embodiment of this disclosure;

[0047] Figure 12 for Figure 11 A flowchart of one method for step S103. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. Furthermore, the embodiments and features in the embodiments of this disclosure can be combined with each other without conflict. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0049] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure pertains. As used in this disclosure, the words “comprising” or “including” and similar terms mean that an element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, but do not exclude other elements or objects.

[0050] Thin-film piezoelectric materials, with their high dielectric constant and transparency, are well-suited for screen-integrated vibrator structures. However, when uneven surface charge distribution leads to accumulation or excessive voltage occurs, the vibrator can break down. For example, the upper and lower electrodes may remain open-circuited, but the piezoelectric thin-film layer structure may be damaged. Alternatively, the upper and lower electrodes may short-circuit due to breakdown, causing the entire vibrator to fail. The main cause of short circuits is the formation of cracks in the piezoelectric thin-film layer due to microparticles, particles, or film stress during the manufacturing process. Depositing electrodes directly onto this cracked layer poses a high risk of short circuits. Therefore, preventing short circuits in piezoelectric sensors has become a pressing technical problem.

[0051] In related technologies, Figure 1 This is a top view of a thin-film oscillating chip with cracks in the piezoelectric layer. During the manufacturing process, microparticles, particles, or film stress can cause cracks in the piezoelectric layer. If electrodes are directly deposited on the piezoelectric layer, these cracks will cause the thin-film oscillating chip to short-circuit, thereby reducing product yield.

[0052] In view of this, the present disclosure provides a piezoelectric sensor, a method for manufacturing the same, and a tactile feedback device to avoid short circuits in the piezoelectric sensor and improve product yield.

[0053] like Figure 2 The diagram shown is a schematic representation of one structure of a piezoelectric sensor provided in this disclosure. The piezoelectric sensor includes:

[0054] The substrate 1, and a first electrode layer 2, a piezoelectric thin film layer 3, an insulating layer 4, and a second electrode layer 5 disposed sequentially away from the substrate 1, wherein the insulating layer 4 is in at least partial contact with the piezoelectric thin film layer 3.

[0055] In specific implementation, the substrate 1 can be a substrate made of glass, a substrate made of silicon or silicon dioxide (SiO2), a substrate made of sapphire, or a substrate made of metal wafers. There are no limitations here. Those skilled in the art can set the substrate 1 according to the actual application needs.

[0056] In specific implementation, the first electrode layer 2 can be made of indium tin oxide (ITO), indium zinc oxide (IZO), or one of titanium-gold (Ti-Au) alloy, titanium-aluminum-titanium (Ti-Al-Ti) alloy, or titanium-molybdenum (TiMo) alloy. Alternatively, it can be made of titanium (Ti), gold (Au), silver (Ag), molybdenum (Mo), copper (Cu), tungsten (W), or chromium (Cr). Those skilled in the art can configure the first electrode layer 2 according to actual application needs, and no limitation is made here. Correspondingly, the second electrode layer 5 can also be made of the same material as the first electrode layer 2, which will not be described in detail here.

[0057] In specific implementation, the piezoelectric thin film layer 3 can be aluminum nitride (AlN), ZnO (zinc oxide), lead zirconate titanate (Pb(Zr,Ti)O3, PZT), barium titanate (BaTiO3), lead titanate (PbTiO3), potassium niobate (KNbO3), lithium niobate (LiNbO3), lithium tantalate (LiTaO3), or lanthanum gallium silicate (La3Ga5SiO3). 14 At least one of the following can be used: In this way, while ensuring the transparency of the piezoelectric sensor, the vibration characteristics of the piezoelectric sensor are also guaranteed. Specifically, the material for fabricating the piezoelectric thin film layer 3 can be selected according to the actual needs of those skilled in the art, and is not limited here. When using PZT to fabricate the piezoelectric thin film layer 3, because PZT has a high piezoelectric coefficient, the piezoelectric characteristics of the corresponding piezoelectric sensor are guaranteed, allowing the corresponding piezoelectric sensor to be applied to haptic feedback devices. Furthermore, PZT has high light transmittance, so when integrated into a display device, it does not affect the display quality of the display device.

[0058] The insulating layer 4 located between the piezoelectric thin film layer 3 and the second electrode layer 5 is in at least partial contact with the piezoelectric thin film layer 3. The insulating layer 4 may also be in complete contact with the piezoelectric thin film layer 3; for example, the insulating layer 4 may completely cover the side of the piezoelectric thin film layer 3 facing away from the substrate 1. Figure 2 The diagram illustrates that the insulating layer 4 completely covers the side of the piezoelectric thin film layer 3 facing away from the substrate 1, and can also partially contact the piezoelectric thin film layer 3. For example, the insulating layer 4 only fills the crack portion in the piezoelectric thin film layer 3, or the insulating layer 4 is only disposed in the portion of the piezoelectric thin film layer 3 facing away from the substrate 1.

[0059] In specific implementation, the piezoelectric thin film layer 3 can be entirely disposed on the side of the first electrode layer 2 facing away from the substrate 1, improving the fabrication efficiency of the piezoelectric sensor. Furthermore, the piezoelectric thin film layer 3 can be patterned as needed; for example, it can be disposed in sections on the side of the first electrode layer 2 facing away from the substrate 1, thus enabling flexible design of the piezoelectric sensor. In specific implementation, since the insulating layer 4 is in at least partial contact with the piezoelectric thin film layer 3, even if cracks exist in the piezoelectric thin film layer 3, the insulating layer 4 can effectively fill the cracks. Therefore, after the deposition of the second electrode layer 5, the presence of the insulating layer 4 prevents short circuits between the second electrode layer 5 and the first electrode layer 2 due to contact, thereby avoiding the short-circuit risk of the piezoelectric sensor and improving product yield.

[0060] In the embodiments disclosed herein, such as Figure 3 The diagram shows one possible structure of the piezoelectric sensor. The piezoelectric thin film layer 3, on the side facing away from the substrate 1, includes at least one hollow structure f, and each hollow structure f is filled with the insulating layer 4. The at least one hollow structure f can be one or more. Figure 3 The diagram illustrates the case where there is only one hollow structure f, but other numbers are also possible and not limited here. The hollow structure f can be a crack present in the piezoelectric thin film layer 3. When there are multiple hollow structures f, the sizes of the individual hollow structures f can be unequal, and their distribution can be randomized according to actual process conditions. For example... Figure 4 The diagram shows that the insulating layer 4 completely fills each of the hollow structures f, and the thickness of the insulating layer 4 filling each hollow structure f is equal to the depth of the corresponding hollow structure f. The thickness direction of the insulating layer 4 and the depth direction of the hollow structure f are both along a direction perpendicular to the plane of the substrate 1. The term "equal" here does not mean completely equal, but rather approximately equal. In this way, the insulating layer 4 effectively fills each hollow structure f in the piezoelectric thin film layer 3, avoiding the risk of short circuits in the piezoelectric sensor. Furthermore, since the insulating layer 4 completely fills each hollow structure f, when the portion of the insulating layer 4, except for filling each hollow structure f, completely covers the side of the piezoelectric thin film layer 3 facing away from the substrate 1, a flush arrangement of the side of the piezoelectric thin film layer 3 facing away from the substrate 1 is achieved, ensuring the structural stability of the piezoelectric sensor in subsequent fabrication and improving the performance of the piezoelectric sensor.

[0061] In this embodiment of the disclosure, combined with Figure 4 and Figure 5 As shown, the orthographic projection of the insulating layer 4 onto the substrate 1 completely falls within the area of ​​the orthographic projection of the piezoelectric thin film layer 3 onto the substrate 1. In specific implementations, the insulating layer 4 can be disposed only in areas of the piezoelectric thin film layer 3 prone to cracking, for example, only in areas containing the perforated structure f. The insulating layer 4 can fill only the perforated structure f, or it can partially fill the perforated structure f. For example, the overall thickness of the piezoelectric thin film layer 3 along the direction perpendicular to the plane of the substrate 1 is b, the depth of the perforated structure f is c, and the thickness of the insulating layer 4 along the direction perpendicular to the plane of the substrate 1 is d, where c ≤ b and d ≤ c. Figure 5 As shown, when the insulating layer 4 completely fills the hollow structure f, b=c=d, as... Figure 6 As shown, when the hollow structure f is partially filled in the insulating layer 4, b=c and d<c. In this way, the hollow structure f on the piezoelectric thin film layer 3 is filled by the insulating layer 4, avoiding the risk of short circuit in the piezoelectric sensor.

[0062] In this disclosed embodiment, it is still combined with Figure 3 As shown, the orthographic projection of the insulating layer 4 on the substrate 1 overlaps with the orthographic projection of the piezoelectric thin film layer 3 on the substrate 1. In specific implementation, the insulating layer 4 can completely cover the side of the piezoelectric thin film layer 3 facing away from the substrate 1. Even if the piezoelectric thin film layer 3 originally has cracks, the insulating layer 4 effectively fills the hollow structure f, avoiding the short-circuit risk of the piezoelectric sensor and improving product yield.

[0063] In this embodiment of the disclosure, the insulating layer 4 includes at least one of polyimide (PI), silicon dioxide (SiO2), and aluminum oxide (Al2O3). In specific implementation, if the piezoelectric thin film layer 3 has the hollow structure f, the hollow structure f will have strong capillary force and pores. When using a wet process, the insulating layer 4 can flow into the hollow structure f through gravity leveling. For example, when using a wet process to coat PI on the side of the piezoelectric thin film layer 3 away from the substrate 1, since PI has good leveling characteristics on the surface of the piezoelectric thin film layer 3, PI can quickly level the hollow structure f. While ensuring the surface flatness of the side of the piezoelectric thin film layer 3 away from the substrate 1, the risk of short circuit of the piezoelectric sensor is avoided. Since PI has good high-temperature curing (cyclization) characteristics, after the wet coating of PI on the side of the piezoelectric thin film layer 3 away from the substrate 1, the PI is cured at high temperature within 200℃~300℃ to form the insulating layer 4, thereby ensuring that the insulating layer 4 has stable insulation characteristics and improving the performance of the piezoelectric sensor.

[0064] In specific implementation, a wet process can also be used to coat SiO2 on the side of the piezoelectric thin film layer 3 away from the substrate 1, thereby leveling the hollow structure f. While ensuring the surface flatness of the side of the piezoelectric thin film layer 3 away from the substrate 1, the risk of short circuit of the piezoelectric sensor is avoided. After wet coating SiO2 on the side of the piezoelectric thin film layer 3 away from the substrate 1, the SiO2 is cured at a high temperature of not less than 300°C to form the insulating layer 4, thereby ensuring that the insulating layer 4 has stable insulation properties and improving the performance of the piezoelectric sensor.

[0065] In specific implementation, a dry deposition process can be used to coat Al2O3 on the side of the piezoelectric thin film layer 3 away from the substrate 1. Due to the insulating properties of Al2O3, the risk of short circuit in the piezoelectric sensor is avoided, thus improving the performance of the piezoelectric sensor. Of course, other methods can also be used to set the piezoelectric thin film layer 3, which will not be described in detail here.

[0066] In this embodiment of the disclosure, the thickness relationship between the insulating layer 4 and the piezoelectric thin film layer 3 must satisfy the following equation:

[0067] d PI ≤0.1 d PZT ;

[0068] Where, d PI d represents the thickness of the insulating layer 4. PZT This indicates the thickness of the piezoelectric thin film layer 3.

[0069] In the specific implementation process, the inventors discovered in actual research that when the thickness of the piezoelectric thin film layer 3 is constant, the thickness of the insulating layer 4 coated on the side of the piezoelectric thin film layer 3 away from the substrate 1 is set to within 10% of the thickness of the piezoelectric thin film layer 3. For example, when the thickness of the piezoelectric thin film layer 3 is 2μm, the thickness of the insulating layer 4 can be 200nm, 100nm, or 50nm, without limitation. In this way, while ensuring the insulation characteristics of the insulating layer 4, the short-circuit risk of the piezoelectric sensor can be avoided, and the vibration characteristics of the piezoelectric sensor under high-frequency AC drive can be guaranteed, thereby improving the performance of the piezoelectric sensor.

[0070] In this embodiment of the disclosure, the thickness of the insulating layer 4 is in the range of [50nm, 200nm].

[0071] In specific implementation, the thickness of the insulating layer 4 is between 50nm and 200nm. For example, the thickness of the insulating layer 4 is 100nm, 60nm, or 50nm. When the thickness of the insulating layer 4 is within the above range, the insulating layer 4 has good insulation characteristics, thereby effectively avoiding the short-circuit risk of the piezoelectric sensor.

[0072] In this embodiment of the disclosure, the thickness of the piezoelectric thin film layer 3 ranges from 0 to 2 μm.

[0073] In specific implementation, the thickness of the piezoelectric thin film layer 3 is between 0 and 2 μm. For example, the thickness of the piezoelectric thin film layer 3 is 0.5 μm, 1 μm, or 2 μm. In practical applications, the thickness of the piezoelectric thin film layer 3 can be set as close to zero as possible to ensure good vibration characteristics of the piezoelectric thin film layer 3 while also taking into account the lightweight design of the piezoelectric sensor.

[0074] In this embodiment of the disclosure, the capacitance relationship between the piezoelectric thin film layer 3 and the insulating layer 4 must satisfy the following equation:

[0075] C PZT ≥100C PI ;

[0076] Among them, C PZT C represents the capacitance of the piezoelectric thin film layer 3. PI This indicates the capacitance of the insulating layer 4.

[0077] In specific implementation, when the material used for the piezoelectric thin film layer 3 is fixed, for example, a film layer made of PbTiO3, and the thickness of the piezoelectric thin film layer 3 is fixed, and the facing area between the first electrode layer 2 and the second electrode layer 5 is fixed, the capacitance of the piezoelectric thin film layer 3 can be determined according to the capacitance calculation formula as follows: ,in, The dielectric constant of the piezoelectric thin film layer 3 is expressed as d, which ranges from 450 to 1500. PZT A represents the thickness of the piezoelectric thin film layer 3, and A represents the area between the first electrode layer 2 and the second electrode layer 5.

[0078] The capacitance relationship between the piezoelectric thin film layer 3 and the insulating layer 4 satisfies: C PZT ≥100C PI At that time, the voltage applied to the piezoelectric thin film layer 3 is: In this way, in C PZT ≥100C PI This design avoids significant voltage loss on the piezoelectric thin film layer 3 due to the insulating layer 4 being located on the surface of the piezoelectric thin film layer 3 facing away from the substrate 1, ensuring good vibration characteristics of the piezoelectric sensor under high-frequency AC drive and thus guaranteeing its performance. Furthermore, when the capacitance of the piezoelectric thin film layer 3 is constant, the material and thickness of the insulating layer 4 can be selected based on the capacitance relationship between the piezoelectric thin film layer 3 and the insulating layer 4. When the insulating layer 4 is made of PI material, its dielectric constant ranges from 2.3 to 2.8. In practical applications, the insulating layer 4 can be configured according to the actual conditions of the piezoelectric thin film layer 3, thus enabling flexible fabrication of the piezoelectric sensor.

[0079] In this embodiment of the disclosure, the resistance relationship between the piezoelectric thin film layer 3 and the insulating layer 4 must satisfy the following equation:

[0080] R PI ≥1000R PZT ;

[0081] Among them, R PZT R represents the resistance of the piezoelectric thin film layer 3. PI This indicates the resistance of the insulating layer 4.

[0082] In specific implementation, when the material used for the piezoelectric thin film layer 3 is fixed, for example, a film layer made of PbTiO3, and when the thickness of the piezoelectric thin film layer 3 is fixed, and the cross-sectional area of ​​the piezoelectric thin film layer 3 parallel to the plane of the substrate 1 is fixed, the resistance of the piezoelectric thin film layer 3 can be determined according to the resistance calculation formula as follows: ,in, The resistivity of the piezoelectric thin film layer 3 is greater than or equal to 10. 9 Ωcm, d PZT The thickness of the piezoelectric thin film layer 3 is indicated by A, which represents the cross-sectional area of ​​the piezoelectric thin film layer 3 parallel to the plane of the substrate 1. This area can be equal to the area of ​​the first electrode layer 2 and the second electrode layer 5 facing each other.

[0083] The resistance relationship between the piezoelectric thin film layer 3 and the insulating layer 4 satisfies R PI ≥1000R PZT When the insulation layer 4 has good insulation properties, it effectively avoids the short-circuit risk of the piezoelectric sensor. When the resistance of the piezoelectric thin film layer 3 is constant, the material and corresponding thickness range of the insulation layer 4 can be determined according to the resistance calculation formula. In practical applications, the insulation layer 4 can be set according to the actual situation of the piezoelectric thin film layer 3, thereby realizing the flexible fabrication of the piezoelectric sensor.

[0084] In this embodiment, a hydrophilic material layer is disposed on the side of the piezoelectric thin film layer 3 facing away from the substrate 1. This hydrophilic material layer not only ensures rapid leveling of the insulating layer 4 on the side of the piezoelectric thin film layer 3 facing away from the substrate 1, but also possesses good high-temperature curing characteristics, guaranteeing stable insulation properties of the insulating layer 4 and thus improving the performance of the piezoelectric sensor.

[0085] In this embodiment, the first electrode layer 2 and the second electrode layer 5 can be configured in the following four ways, with the first implementation still combining... Figure 2 As shown, the first electrode layer 2 and the second electrode layer 5 are both plate-like structures of the whole layer, or at least one of the first electrode layer 2 and the second electrode layer 5 may include a pattern design, and the orthographic projection of the second electrode layer 5 on the substrate 1 completely falls within the area of ​​the orthographic projection of the first electrode layer 2 on the substrate 1.

[0086] In this embodiment of the disclosure, the second implementation is as follows: Figure 6 As shown, the first electrode layer 2 has multiple first columnar structures 10 on the side near the piezoelectric thin film layer 3, and the second electrode layer 5 is a whole-layer plate structure, or the second electrode layer 5 may also include a patterned design. In this way, while preventing the piezoelectric sensor from short-circuiting through the insulating layer 4, the multiple first columnar structures 10 increase the contact area between the piezoelectric thin film layer 3 and the first electrode layer 2, ensuring the structural stability between the piezoelectric thin film layer 3 and the first electrode layer 2, and improving the performance of the piezoelectric sensor.

[0087] In specific implementation, all the first columnar structures 10 have the same size. The first columnar structures 10 can be distributed with unequal spacing or with equal spacing, depending on the actual application requirements. No limitation is made here. When the first columnar structures 10 are distributed with equal spacing, the uniformity of transmittance at all locations of the piezoelectric sensor is ensured, thus guaranteeing the performance of the piezoelectric sensor.

[0088] In this embodiment of the disclosure, the third implementation is as follows: Figure 7 As shown, the first electrode layer 2 is a single-layer plate structure, or the first electrode layer 2 may include a pattern design. The second electrode layer 5 has multiple second columnar structures 20 on the side near the piezoelectric thin film layer 3. In this way, while preventing the piezoelectric sensor from short-circuiting through the insulating layer 4, the multiple second columnar structures 20 increase the contact area between the piezoelectric thin film layer 3 and the second electrode layer 5, ensuring the structural stability between the piezoelectric thin film layer 3 and the second electrode layer 5, and improving the performance of the piezoelectric sensor.

[0089] In practical implementation, all the second columnar structures 20 have the same size. The second columnar structures 20 can be distributed with unequal spacing or with equal spacing, depending on the actual application requirements. No limitation is made here. When the second columnar structures 20 are distributed with equal spacing, the uniformity of light transmittance at all locations of the piezoelectric sensor is ensured, thus guaranteeing the performance of the piezoelectric sensor.

[0090] In this disclosure embodiment, the fourth implementation is as follows: Figure 8As shown, the first electrode layer 2 has multiple third columnar structures 30 on the side near the piezoelectric thin film layer 3, and the second electrode layer 5 has multiple fourth columnar structures 40 on the side near the piezoelectric thin film layer 3. The orthographic projection of any third columnar structure 30 on the substrate 1 and the orthographic projection of any fourth columnar structure 40 on the substrate 1 do not overlap. The multiple third columnar structures 30 increase the contact area between the piezoelectric thin film layer 3 and the first electrode layer 2, and the multiple fourth columnar structures 40 increase the contact area between the piezoelectric thin film layer 3 and the second electrode layer 5, thereby ensuring the structural stability of the piezoelectric thin film layer 3 with the first electrode layer 2 and the second electrode layer 5 respectively, and improving the performance of the piezoelectric sensor. Furthermore, the orthographic projections of any of the third columnar structures 30 and any of the fourth columnar structures 40 on the substrate 1 do not overlap. For example, the orthographic projection of any of the fourth columnar structures 40 on the substrate 1 falls entirely within the area of ​​the orthographic projection of the gap between two adjacent third columnar structures 30 on the substrate 1. While ensuring structural stability, this also guarantees the uniformity of the piezoelectric thin film layer 3 thickness, avoiding the occurrence of breakdown at thinner locations due to uneven thickness of the piezoelectric thin film layer 3, thereby ensuring the performance of the piezoelectric sensor.

[0091] In specific implementation, all the third columnar structures 30 and all the fourth columnar structures 40 have the same size. The third columnar structures 30 can be distributed with unequal spacing or with uniform spacing. Similarly, the fourth columnar structures 40 can be distributed with unequal spacing or with uniform spacing. The specific distribution of the third columnar structures 30 and the fourth columnar structures 40 can be set according to actual application needs, and is not limited here. When the third columnar structures 30 and the fourth columnar structures 40 are distributed with equal spacing, the uniformity of light transmittance at all positions of the piezoelectric sensor is ensured, thus guaranteeing the performance of the piezoelectric sensor.

[0092] Of course, in practical applications, in addition to the above four implementation methods for setting the first electrode layer 2 and the second electrode layer 5, other methods can be used to set the first electrode layer 2 and the second electrode layer 5 according to actual needs, which will not be described in detail here.

[0093] It should be noted that the thickness of the first electrode layer 2 is between 50 nm and 500 nm, and the thickness of the second electrode layer 5 is between 50 nm and 500 nm. For example, the thickness of the first electrode layer 2 is 200 nm, and the thickness of the second electrode layer 5 is 150 nm. In specific implementations, the thicknesses of the first electrode layer 2 and the second electrode layer 5 can be set according to actual application needs, and are not limited here. The term "same" in this disclosure does not mean completely identical, but can mean approximately identical or roughly identical.

[0094] In this embodiment of the disclosure, such as Figure 9 The diagram shows one possible structure of the piezoelectric sensor. In addition to the aforementioned film layers, the piezoelectric sensor may also include a protective layer 6 disposed around the first electrode layer 2, the piezoelectric thin film layer 3, the insulating layer 4, and the second electrode layer 5, and a wiring layer 7 coupled through vias penetrating the protective layer 6. In a specific implementation, utilizing the inverse piezoelectric effect, the first electrode layer 2 is grounded, and a high-frequency AC voltage signal (V0) is applied to the second electrode layer 5. AC The piezoelectric sensor applies a high-frequency AC voltage signal to the piezoelectric thin film layer 3 and the insulating layer 4, thereby generating high-frequency vibration. Laser can be used to measure the vibration displacement, ensuring the performance of the piezoelectric sensor. The protective layer can be SiO2, silicon nitride (Si3N4), etc., and is not limited here. Of course, in addition to the various film layers mentioned above, other film layers can be used in the piezoelectric sensor according to the actual application; specific details can be found in related technologies.

[0095] It should be noted that, in this embodiment, the first electrode layer 2, the piezoelectric thin film layer 3, the insulating layer 4, and the second electrode layer 5, which are sequentially stacked along the substrate 1, each have a decreasing projected area on the substrate 1. That is, the projected area of ​​the second electrode layer 5 on the substrate 1 completely falls within the area of ​​the projected area of ​​the insulating layer 4 on the substrate 1, the projected area of ​​the insulating layer 4 on the substrate 1 completely falls within the area of ​​the projected area of ​​the piezoelectric thin film layer 3 on the substrate 1, and the projected area of ​​the piezoelectric thin film layer 3 on the substrate 1 completely falls within the area of ​​the projected area of ​​the first electrode layer 2 on the substrate 1. This creates a step difference between the layers, ensuring rapid leveling during the wet processing of each layer and maintaining the structural stability of the piezoelectric sensor, thereby improving its performance. Furthermore, the piezoelectric sensor can be applied in fields such as medical devices, automotive electronics, and motion tracking systems. It is particularly suitable for wearable devices, external or implantable medical monitoring and treatment, or applications in fields such as artificial intelligence electronic skin. Specifically, the piezoelectric sensor can be applied to devices that generate vibration and mechanical properties, such as brake pads, keyboards, mobile terminals, game controllers, and vehicle components.

[0096] Based on the same publicly disclosed concept, such as Figure 10 As shown, this disclosure also provides a tactile feedback device, which includes a tactile feedback circuit 100 and a piezoelectric sensor 200 as described above; wherein:

[0097] The tactile feedback circuit 100 is located on the side of the second electrode layer 5 away from the first electrode layer 2, or on the side of the first electrode layer 2 away from the second electrode layer 5. The tactile feedback circuit 100 is used to generate voltage pulses according to the received instructions to make the structure vibrate.

[0098] In the specific implementation process, such as Figure 10 The diagram illustrates that the haptic feedback circuit 100 is located on the side of the first electrode layer 2 opposite to the second electrode layer 5. For example, the haptic feedback device can be integrated with a touchscreen. The touchscreen can determine the position of the human touch, thereby generating corresponding vibration waveforms, amplitudes, and frequencies, enabling human-computer interaction. Alternatively, the haptic feedback device can be reused as a piezoelectric element. The piezoelectric sensor can determine the position of the human touch, thereby generating corresponding vibration waveforms, amplitudes, and frequencies, also enabling human-computer interaction. Of course, the haptic feedback device can also be applied in fields such as medical treatment, automotive electronics, and motion tracking systems, depending on actual needs, which will not be detailed here.

[0099] Furthermore, the principle of the tactile feedback device in solving the problem is similar to that of the aforementioned piezoelectric sensor. Therefore, the relevant structure of the piezoelectric sensor 200 in the tactile feedback device can be implemented with reference to the aforementioned piezoelectric sensor 200 section, and the repeated parts will not be described again.

[0100] Based on the same publicly disclosed concept, such as Figure 11 As shown in the embodiments of this disclosure, a method for manufacturing a piezoelectric sensor is also provided, comprising:

[0101] S101: Form a first electrode layer on the substrate;

[0102] S102: A piezoelectric thin film layer is formed on the side of the first electrode layer away from the substrate.

[0103] S103: An insulating layer is formed on the side of the piezoelectric thin film layer away from the first electrode layer, which is in at least partial contact with the piezoelectric thin film layer;

[0104] S104: A second electrode layer is formed on the side of the insulating layer opposite to the piezoelectric thin film layer.

[0105] In the specific implementation process, the specific structure of the piezoelectric sensor in the manufacturing method is the same as described in the foregoing section, and will not be detailed here again. The specific implementation process of steps S101 to S103 is as follows:

[0106] First, a first electrode layer 2 is formed on the substrate 1. For example, ITO is sputtered onto the substrate 1, and then the ITO is patterned by photolithography and etching to form the first electrode layer 2 with the desired pattern. Then, a piezoelectric thin film layer 3 is formed on the side of the first electrode layer 2 away from the substrate 1. For example, the piezoelectric thin film layer 3 is deposited on the side of the first electrode layer 2 away from the substrate 1, and then the piezoelectric thin film layer 3 is patterned by photolithography and etching to form the piezoelectric thin film layer 3 with the desired pattern. Then, an insulating layer 4 is coated on the side of the piezoelectric thin film layer 3 away from the first electrode layer 2, which is at least partially in contact with the piezoelectric thin film layer 3. Then, a second electrode layer 5 is formed on the side of the insulating layer 4 away from the piezoelectric thin film layer 3. For example, ITO is sputtered on the side of the insulating layer 4 away from the piezoelectric thin film layer 3, and then the ITO is patterned by photolithography and etching to form the second electrode layer 5 with the desired pattern.

[0107] In the embodiments disclosed herein, such as Figure 12 As shown, step S103: forming an insulating layer that is at least partially in contact with the piezoelectric thin film layer on the side of the piezoelectric thin film layer opposite to the first electrode layer, including:

[0108] S201: Using a wet process, polyimide material is coated on the side of the piezoelectric thin film layer away from the first electrode layer;

[0109] S202: The polyimide material is cured at high temperature to form an insulating layer that is at least partially in contact with the piezoelectric film layer on the side of the piezoelectric film layer away from the first electrode layer.

[0110] In the specific implementation process, steps S201 to S202 are implemented as follows:

[0111] First, using a wet process, polyimide material is coated on the side of the piezoelectric thin film layer 3 facing away from the first electrode layer 2. Even if cracks exist in the piezoelectric thin film layer 3, the polyimide material will flow into the cracks due to the strong capillary force and porosity at the cracks, thus ensuring the insulation properties between the piezoelectric thin film layer 3 and the second electrode layer 5. Then, the polyimide material is cured at high temperature, forming an insulating layer 4 that is at least partially in contact with the piezoelectric thin film layer 3 on the side facing away from the first electrode layer 2. For example, the polyimide material is cured at 200°C, ensuring that the insulating layer 4 has stable insulation properties, thereby guaranteeing the performance of the piezoelectric sensor.

[0112] In practical implementation, the principle of the above-mentioned piezoelectric sensor manufacturing method is similar to that of the aforementioned piezoelectric sensor. Therefore, the manufacturing method of the piezoelectric sensor can refer to the implementation of the aforementioned piezoelectric sensor section, and the repeated parts will not be repeated.

[0113] This disclosure provides a piezoelectric sensor and its fabrication method. The piezoelectric sensor includes a substrate 1, and a first electrode layer 2, a piezoelectric thin film layer 3, an insulating layer 4, and a second electrode layer 5 sequentially opposite to the substrate 1. The insulating layer 4 is in at least partial contact with the piezoelectric thin film layer 3. Even if there are cracks in the piezoelectric thin film layer 3, the cracks are effectively filled by the insulating layer 4. In this way, after the second electrode layer 5 is deposited, the insulating layer 4 avoids the risk of short circuit between the second electrode layer 5 and the first electrode layer 2 due to contact, thus avoiding the short circuit risk of the piezoelectric sensor and improving the product yield.

[0114] Although preferred embodiments of this disclosure have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this disclosure.

[0115] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.

Claims

1. A piezoelectric sensor, wherein, The piezoelectric sensor, used in haptic feedback devices, provides vibration feedback under high-frequency AC drive and comprises: A substrate, and a first electrode layer, a piezoelectric thin film layer, an insulating layer, and a second electrode layer disposed sequentially away from the substrate, wherein the insulating layer is in at least partial contact with the piezoelectric thin film layer; the insulating layer covers the side of the piezoelectric thin film layer away from the substrate. The thickness relationship between the insulating layer and the piezoelectric thin film layer must satisfy the following equation: d PI ≤0.1 d PZT ; Where, d PI d represents the thickness of the insulating layer. PZT The thickness of the piezoelectric thin film layer is indicated, and the thickness range of the piezoelectric thin film layer is (0, 2 μm); The first electrode layer has a plurality of first columnar structures on the side near the piezoelectric thin film layer, and / or the second electrode layer has a plurality of second columnar structures on the side near the piezoelectric thin film layer.

2. The piezoelectric sensor as described in claim 1, wherein, The side of the piezoelectric thin film layer facing away from the substrate includes at least one hollow structure, and each hollow structure is filled with the insulating layer.

3. The piezoelectric sensor according to any one of claims 1-2, wherein, The orthographic projection of the insulating layer on the substrate falls entirely within the region of the orthographic projection of the piezoelectric thin film layer on the substrate.

4. The piezoelectric sensor according to any one of claims 1-2, wherein, The orthographic projection of the insulating layer on the substrate overlaps with the orthographic projection of the piezoelectric thin film layer on the substrate.

5. The piezoelectric sensor as described in claim 1, wherein, The insulating layer includes at least one of polyimide, silicon dioxide, and aluminum oxide.

6. The piezoelectric sensor as claimed in claim 1, wherein, The thickness of the insulating layer ranges from 50 nm to 200 nm.

7. The piezoelectric sensor as claimed in claim 1, wherein, The capacitance relationship between the piezoelectric thin film layer and the insulating layer must satisfy the following equation: C PZT ≥100C PI ; Among them, C PZT C represents the capacitance of the piezoelectric thin film layer. PI This indicates the capacitance of the insulating layer.

8. The piezoelectric sensor as claimed in claim 1, wherein, The resistance relationship between the piezoelectric thin film layer and the insulating layer must satisfy the following equation: R PI ≥1000R PZT ; Among them, R PZT R represents the resistance of the piezoelectric thin film layer. PI This indicates the resistance of the insulating layer.

9. The piezoelectric sensor as claimed in claim 1, wherein, A hydrophilic material layer is disposed on the side of the piezoelectric thin film layer facing away from the substrate.

10. The piezoelectric sensor as claimed in claim 1, wherein, The piezoelectric thin film layer includes at least one of aluminum nitride, zinc oxide, lead zirconate titanate, barium titanate, lead titanate, potassium niobate, lithium niobate, lithium tantalate, and lanthanum gallium silicate.

11. The piezoelectric sensor as claimed in claim 1, wherein, The first electrode layer has a plurality of third columnar structures on the side near the piezoelectric thin film layer, and the second electrode layer has a plurality of fourth columnar structures on the side near the piezoelectric thin film layer. The orthographic projection of any third columnar structure on the substrate and the orthographic projection of any fourth columnar structure on the substrate do not overlap.

12. A haptic feedback device, wherein, Includes a haptic feedback circuit and a piezoelectric sensor as described in any one of claims 1-11; wherein: The tactile feedback circuit is located on the side of the second electrode layer away from the first electrode layer, or on the side of the first electrode layer away from the second electrode layer. The tactile feedback circuit is used to generate voltage pulses according to the received instructions to make the structure vibrate.

13. A method for manufacturing a piezoelectric sensor, wherein, The piezoelectric sensor is used in a tactile feedback device, and the piezoelectric sensor is used for vibration feedback under high-frequency AC drive. The manufacturing method includes: A first electrode layer is formed on a substrate. A piezoelectric thin film layer is formed on the side of the first electrode layer that is away from the substrate. An insulating layer is formed on the side of the piezoelectric thin film layer opposite to the first electrode layer, in at least partial contact with the piezoelectric thin film layer; the insulating layer covers the side of the piezoelectric thin film layer opposite to the substrate; wherein the thickness relationship between the insulating layer and the piezoelectric thin film layer must satisfy the following relationship: d PI ≤0.1 d PZT ; where d PI d represents the thickness of the insulating layer. PZT The thickness of the piezoelectric thin film layer is indicated, and the thickness range of the piezoelectric thin film layer is (0, 2 μm); A second electrode layer is formed on the side of the insulating layer away from the piezoelectric thin film layer; the first electrode layer has a plurality of first columnar structures on the side near the piezoelectric thin film layer, and / or the second electrode layer has a plurality of second columnar structures on the side near the piezoelectric thin film layer.

14. The manufacturing method as described in claim 13, wherein, The method of forming an insulating layer that is at least partially in contact with the piezoelectric thin film layer on the side of the piezoelectric thin film layer opposite to the first electrode layer includes: A wet process is used to coat the piezoelectric thin film layer with polyimide material on the side opposite to the first electrode layer; The polyimide material is cured at high temperature to form an insulating layer that is at least partially in contact with the piezoelectric film layer on the side of the piezoelectric film layer away from the first electrode layer.

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