WO2023184298A1 - 压电传感器、其驱动方法及触觉反馈装置 - Google Patents

压电传感器、其驱动方法及触觉反馈装置 Download PDF

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WO2023184298A1
WO2023184298A1 PCT/CN2022/084282 CN2022084282W WO2023184298A1 WO 2023184298 A1 WO2023184298 A1 WO 2023184298A1 CN 2022084282 W CN2022084282 W CN 2022084282W WO 2023184298 A1 WO2023184298 A1 WO 2023184298A1
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layer
piezoelectric sensor
electrode layer
piezoelectric
electrode
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PCT/CN2022/084282
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English (en)
French (fr)
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陈右儒
花慧
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京东方科技集团股份有限公司
北京京东方技术开发有限公司
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Priority to CN202280000636.9A priority Critical patent/CN117203600A/zh
Priority to PCT/CN2022/084282 priority patent/WO2023184298A1/zh
Publication of WO2023184298A1 publication Critical patent/WO2023184298A1/zh

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer

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  • the present disclosure relates to the technical field of tactile feedback, and in particular to a piezoelectric sensor, its driving method and a tactile feedback device.
  • Tactile feedback (Haptics) is the focus of current technology development. Specifically, tactile feedback can enable the terminal to interact with the human body through the sense of touch. Tactile feedback can be divided into two categories, one is vibration feedback and the other is tactile reproduction technology.
  • surface tactile reproduction technology can perceive the characteristics of objects through bare finger touch screen and achieve efficient and natural interaction on multimedia terminals. It has huge research value and has received widespread attention from domestic and foreign researchers.
  • surface tactility refers to the interaction between the surface roughness of an object and the surface of the skin (fingertips), forming different friction forces due to different surface structures. Therefore, by controlling surface friction, different tactile/tactile sensations can be simulated.
  • Embodiments of the present disclosure provide a piezoelectric sensor, its driving method and tactile feedback device.
  • the specific solutions are as follows:
  • Embodiments of the present disclosure provide a driving method for a piezoelectric sensor.
  • the piezoelectric sensor includes: a substrate, and a first electrode layer, a piezoelectric film layer and a second electrode layer located on the substrate; Wherein, the first electrode layer is grounded, and the second electrode layer is coupled to the driving signal terminal;
  • the driving method includes: loading a ground signal to the first electrode layer, and loading a driving signal superposed by a DC voltage and an AC voltage to the second electrode layer.
  • the effect of the alternating electric field formed by the piezoelectric film layer between the first electrode layer and the second electrode layer The deformation occurs under the force and the force satisfies the following formula:
  • F is the acting force
  • ⁇ is the coefficient
  • a 0 is the voltage value of the DC voltage
  • a 1 sin( ⁇ t) is the voltage value of the AC voltage
  • a 1 is the peak value of the driving signal waveform
  • d 33 is the piezoelectric constant.
  • a 0 is greater than 0.
  • a 0
  • the substrate includes a flexible substrate or a glass substrate.
  • the thickness of the piezoelectric film layer is 1 ⁇ m to 10 ⁇ m.
  • the density of the piezoelectric film layer is 95% to 100%.
  • the piezoelectric film layer includes lead zirconate titanate, and the ratio relationship of the atomic percentage content in the lead zirconate titanate is as follows:
  • the voltage value of the DC voltage is greater than 0.
  • the voltage value of the DC voltage is equal to the peak value of the AC voltage.
  • an embodiment of the present disclosure also provides a piezoelectric sensor, which is driven by any of the above driving methods provided by the embodiment of the present disclosure;
  • the piezoelectric sensor includes: a substrate. , and a first electrode layer, a piezoelectric film layer and a second electrode layer located on the base substrate; wherein the first electrode layer is grounded, and the second electrode layer is coupled to the driving signal terminal.
  • the above-mentioned piezoelectric sensor provided by the embodiment of the present disclosure further includes a first barrier layer located between the first electrode layer and the piezoelectric film layer, and the first The barrier layer is used to block ions from the piezoelectric film layer from diffusing to the first electrode layer.
  • the material of the first barrier layer is Ti.
  • the thickness of the first barrier layer is less than 10 nm.
  • the transmittance of the first barrier layer is greater than or equal to 60%.
  • the material of the first barrier layer includes Pt, HfO 2 or LiNbO 3 .
  • the above-mentioned piezoelectric sensor provided by the embodiment of the present disclosure further includes a second barrier layer located between the first barrier layer and the piezoelectric film layer, and the second barrier layer
  • the material of the barrier layer is different from the material of the first barrier layer, and the second barrier layer is used to block the diffusion of ions of the piezoelectric film layer to the first electrode layer.
  • the material of the second barrier layer is HfO 2 or LiNbO 3 .
  • the thickness of the second barrier layer is less than 50 nm.
  • the above-mentioned piezoelectric sensor provided by the embodiment of the present disclosure also includes:
  • An organic insulating layer is located on the side of the second electrode layer facing away from the base substrate.
  • the organic insulating layer has a first via hole, and the orthographic projection of the first via hole on the base substrate is the same as the orthogonal projection of the first via hole on the base substrate. Orthographic projections of the second electrode layer on the base substrate overlap each other;
  • An inorganic insulating layer is located on the side of the organic insulating layer facing away from the base substrate, and the inorganic insulating layer does not at least partially overlap with the first via hole;
  • a wiring layer is located on the side of the inorganic insulating layer facing away from the base substrate.
  • the wiring layer includes wiring, and one end of the wiring passes through at least part of the first via hole and the second electrode. layer electrical connection.
  • the inorganic insulating layer covers the sidewall of the first via hole and extends to contact the second electrode layer.
  • the contact boundary between the inorganic insulating layer and the second electrode layer is the first boundary
  • the contact boundary between the organic insulating layer and the second electrode is the second boundary
  • the distance between the first boundary and the second boundary is greater than 30% of the thickness of the piezoelectric film layer And less than 60% of the thickness of the piezoelectric film layer.
  • the inorganic insulating layer covers the side wall of the first via hole and covers the second electrode exposed by the first via hole.
  • layer, the part of the inorganic insulating layer covering the second electrode layer has at least one second via hole, and one end of the trace passes through the first via hole and the second via hole and the second via hole.
  • the electrode layers are electrically connected.
  • the above-mentioned piezoelectric sensor provided by the embodiment of the present disclosure further includes: a binding electrode arranged in the same layer as the first electrode layer, the binding electrode being close to the substrate The edge of the substrate is provided, and the other end of the trace is electrically connected to the binding electrode through a third via hole provided on the inorganic insulation layer and the organic insulation layer.
  • the binding electrode is used to connect all The drive signal terminal.
  • the number of the inorganic insulating layers is one layer.
  • the material of the inorganic insulating layer includes SiO 2 , Al 2 O 3 or Si 3 N 4 .
  • the inorganic insulating layer includes at least two sub-layers arranged in a stack, and the materials of the two sub-layers are different.
  • the material of each sub-layer includes SiO 2 , Al 2 O 3 or Si 3 N 4 .
  • the shape of the wiring layer is a grid-like structure, and the material of the wiring layer is Ti/Ni/Au, Ti /Au or Ti/Al/Ti.
  • the thickness of the inorganic insulating layer is 100 nm to 300 nm.
  • an embodiment of the present disclosure also provides a tactile feedback device, including the piezoelectric sensor described in any of the above provided by the embodiment of the present disclosure.
  • Figure 1 is a schematic structural diagram of a piezoelectric sensor provided in the related art
  • Figure 2 is a schematic structural diagram of a piezoelectric sensor provided by an embodiment of the present disclosure
  • Figure 3 is a schematic structural diagram of another piezoelectric sensor provided by an embodiment of the present disclosure.
  • Figure 4 is a schematic structural diagram of another piezoelectric sensor provided by an embodiment of the present disclosure.
  • Figure 5 is a schematic structural diagram of another piezoelectric sensor provided by an embodiment of the present disclosure.
  • Figure 6 is a schematic structural diagram of another piezoelectric sensor provided by an embodiment of the present disclosure.
  • Figure 7 is a schematic structural diagram of another piezoelectric sensor provided by an embodiment of the present disclosure.
  • Figure 8 is a schematic diagram of a driving signal provided by an embodiment of the present disclosure.
  • Figure 9 is a schematic diagram of another driving signal provided by an embodiment of the present disclosure.
  • Figure 10 is a relationship curve between the vibration displacement of the piezoelectric sensor provided by the embodiment of the present disclosure and the driving signal loaded on the second electrode layer;
  • Figure 11 is a schematic diagram of the vibration effect of the piezoelectric sensor
  • Figure 12 is a schematic structural diagram of a piezoelectric sensor provided in the related art.
  • Figure 13 is a schematic structural diagram of another piezoelectric sensor provided in the related art.
  • Figure 14 is a top view of some of the film layers in the piezoelectric sensor.
  • Figure 15 is a partial enlarged schematic diagram of Figure 14;
  • Figure 16 shows the vibration displacement-driving signal curves of five types of piezoelectric sensors under different driving conditions.
  • FIG. 1 is the structure of a PZT thin film piezoelectric sensor, including a base substrate 1 and a first electrode layer 2, a piezoelectric thin film layer 3, a second electrode layer 4, and an insulating layer located on the base substrate 1. 5 and wiring layer 6, wiring layer 6 is electrically connected to the second electrode layer 4 through a via hole penetrating the insulating layer 5.
  • the manufacturing process of the piezoelectric thin film layer 3 is to deposit on the first electrode layer 2 and anneal after deposition.
  • the piezoelectric film layer 3 after annealing Internal stress is easily generated in the thin film layer 3 . If the piezoelectric thin film layer 3 is deposited on the first electrode layer 2 (ITO), and if the crystallization annealing temperature of the piezoelectric thin film layer 3 is 500°C-700°C, considering the influence of the thermal expansion coefficient, there will be presence on the PZT/ITO interface after returning to room temperature. A sheet of stress (shown by the arrow).
  • the PZT thin film piezoelectric sensor is driven by loading the first electrode layer 2 with a ground signal, and the second electrode layer 4 by loading a sine wave signal with a symmetrical signal center at 0V. Due to the tensile stress on the PZT/ITO interface, the PZT film is greatly affected. When the piezoelectric sensor (actuator) operates, if the second electrode layer 4 is still loaded with a sine wave signal with a symmetrical signal center at 0V, the PZT thin film piezoelectric sensor cannot work effectively.
  • the piezoelectric sensor includes: a base substrate 1, and a first electrode located on the base substrate 1 Layer 2, piezoelectric film layer 3 and second electrode layer 4; wherein, the first electrode layer 2 is grounded, and the second electrode layer 4 is coupled to the driving signal terminal;
  • the driving signal V superposed by the DC voltage V dc and the AC voltage V AC is applied to the second electrode layer 4 of the piezoelectric sensor.
  • the DC voltage V dc can cause the electric current inside the piezoelectric film layer to change.
  • the domain preferential orientation can overcome the stress inside the piezoelectric film layer, thereby overcoming the constraints of the substrate substrate 1, so that the piezoelectric film layer has a greater performance under the driving signal V superposed by the direct current voltage V dc and the alternating voltage V AC . vibration displacement, thereby improving the performance of the piezoelectric sensor.
  • the embodiment of the present disclosure loads a ground signal to the first electrode layer 2 close to the base substrate 1, and loads a DC voltage V dc and an AC voltage V dc superimposed on the second electrode layer 4 far away from the base substrate 1.
  • the driving signal V as an example, of course, in specific implementation, the ground signal can also be loaded to the second electrode layer 4 far away from the base substrate 1, and the DC voltage V dc and the first electrode layer 2 close to the base substrate 1 can be loaded.
  • the AC voltage V dc is superimposed on the driving signal V.
  • the substrate substrate 1 provided by the embodiment of the present disclosure may include a flexible substrate substrate (such as PI, etc.) or a glass substrate substrate.
  • the base substrate 1 can also be a substrate made of silicon or silicon dioxide (SiO 2 ), a substrate made of sapphire, or a metal wafer.
  • the substrate is not limited here, and those skilled in the art can set the base substrate 1 according to actual application needs.
  • the manufacturing process of the piezoelectric thin film layer 3 provided by the embodiment of the present disclosure may be a vapor deposition process (CVD), a sputtering process (Sputter) or a sol-gel process (Sol-Gel).
  • CVD vapor deposition process
  • Sputter sputtering process
  • Sol-Gel sol-gel process
  • the thickness of the piezoelectric film layer 3 provided by the embodiment of the present disclosure may be 1 ⁇ m to 10 ⁇ m.
  • the density of the piezoelectric film layer 3 provided by the embodiment of the present disclosure is 95% to 100%.
  • the material of the piezoelectric film layer 3 provided by the embodiment of the present disclosure may include lead zirconate titanate (Pb(Zr,Ti)O 3 , PZT).
  • Pb(Zr,Ti)O 3 , PZT lead zirconate titanate
  • the ratio of the atomic percentage content in lead zirconate titanate is as follows:
  • the piezoelectric film layer 3 formed in this way has excellent piezoelectric coefficient, ensuring the piezoelectric characteristics of the corresponding piezoelectric sensor.
  • the piezoelectric film layer 3 is not limited to the above-mentioned PZT, but can also be aluminum nitride (AlN), ZnO (zinc oxide), barium titanate (BaTiO 3 ), lead titanate (PbTiO 3 ) , at least one of potassium niobate (KNbO 3 ), lithium niobate (LiNbO 3 ), lithium tantalate (LiTaO 3 ), and lanthanum gallium silicate (La 3 Ga 5 SiO 14 ).
  • the details can be determined by those skilled in the art.
  • the material for making the piezoelectric film layer must be selected according to the actual use needs, and is not limited here.
  • the piezoelectric characteristics of the corresponding piezoelectric sensor are guaranteed.
  • the corresponding piezoelectric sensor can be applied to tactile feedback devices, and PZT has The high light transmittance does not affect the display quality of the display device when integrated into the display device.
  • the second electrode layer 4 is loaded with a DC voltage V dc and an AC
  • the voltage V dc is superimposed on the driving signal V, so an alternating electric field is formed between the first electrode layer 2 and the second electrode layer 4 , and the piezoelectric film layer 3 is formed between the first electrode layer 2 and the second electrode layer 4
  • Deformation occurs under the action of the alternating electric field to generate an action force F.
  • the action force F satisfies the following formula:
  • ⁇ is the coefficient
  • a 0 is the voltage value of the above-mentioned DC voltage
  • a 1 sin ( ⁇ t) is the voltage value of the above-mentioned AC voltage
  • a 1 is the peak value of the driving signal waveform
  • d 33 is the piezoelectric constant.
  • the acting force F can be determined according to the tactile feedback effect required by the user, and then the driving signal V that needs to be loaded on the second electrode layer 4 is determined based on the acting force F, thereby determining a 0 and a 1 .
  • the peak value of the drive signal waveform (generally a sinusoidal waveform) is the maximum value based on the 0 scale, and may be positive or negative.
  • the peak-to-peak value of the drive signal waveform is the difference between the maximum value and the minimum value, and is only positive.
  • the peak-to-peak value describes the range of changes in signal values.
  • the relationship between peak value and peak value The peak value refers to the difference between the highest value or the lowest value of the signal and the average value within a period. Generally speaking, the peak value is only defined for signals that are symmetrical up and down. That is, the peak value is equal to half of the peak value.
  • the driving method provided by the embodiment of the present disclosure can make the electric domains inside the piezoelectric film layer 3 preferentially oriented, and can overcome the stress inside the piezoelectric film layer 3 , so that the piezoelectric film layer 3 has a larger vibration displacement driven by the driving signal V superposed by the direct current voltage V dc and the alternating voltage V AC , thereby improving the performance of the piezoelectric sensor.
  • the voltage value a0 of the direct current voltage V dc satisfies: a 0 -
  • Figure 10 is a relationship curve between the vibration displacement (nm) of the piezoelectric sensor provided by the embodiment of the present disclosure and the driving signal (V) loaded on the second electrode layer, where V PP (Voltage Peak- Peak) is the peak-to-peak voltage.
  • V PP Voltage Peak- Peak
  • the driving signal of V PP 16V)
  • point F indicates that the DC voltage is loaded to the second electrode layer 4 at the same time.
  • Figure 11 is a schematic diagram of the vibration effect of the piezoelectric sensor obtained by laser vibration measurement.
  • the embodiment of the present disclosure simultaneously loads the driving signal of the superposed DC voltage and AC voltage to the second electrode layer, and when the voltage value of the DC voltage is equal to the peak value a 1 of the AC voltage V AC , the piezoelectric film layer has Larger vibration displacement, thereby improving the performance of the piezoelectric sensor.
  • An embodiment of the present disclosure provides a piezoelectric sensor, as shown in Figures 2 to 7.
  • the piezoelectric sensor is driven by the aforementioned piezoelectric sensor driving method, which can cause the piezoelectric sensor to have a larger vibration displacement.
  • the piezoelectric sensor includes: a base substrate 1, and a first electrode layer 2, a piezoelectric film layer 3 and a second electrode layer 4 located on the base substrate 1; wherein the first electrode layer 2 is grounded, and the second electrode Layer 4 is coupled to the driving signal terminal.
  • PZT piezoelectric thin film layers
  • process methods for making piezoelectric thin film layers including dry coating (sputtering, Sputter) and wet coating (sol-gel method, Sol-Gel).
  • sputtering sputter
  • sol-gel method sol-Gel
  • PZT material needs to go through a high-temperature annealing process. This process requires PZT grain growth in an air environment of 550°C-650°C to form a good solid solution phase.
  • the vibrator structure needs to use transparent electrodes (such as ITO) as the base electrode and growth layer.
  • transparent electrodes such as ITO
  • the inventor of this case has verified that the Pb ions are all It has a diffusion of about 100nm. In addition to causing the resistance of ITO to increase, this diffusion will also cause Pb ions to be lost in the PZT film layer, causing the perovskite phase to shift to the Pyrochlore phase, reducing the piezoelectric performance of PZT, thereby reducing the performance of the piezoelectric device. . Therefore, in the above-mentioned piezoelectric sensor provided by the embodiment of the present disclosure, as shown in Figure 2, it also includes a first barrier layer 7 located between the first electrode layer 2 and the piezoelectric film layer 3. The first barrier layer 7 is The ions in the blocking piezoelectric film layer 3 diffuse to the first electrode layer 2 .
  • the piezoelectric thin film layer 3 (such as PZT) can be formed by dry coating or wet coating.
  • the PZT material needs to undergo high-temperature annealing. This process requires PZT grain growth in an air environment of 550°C-650°C to form a good solid solution phase.
  • the first electrode layer 2 (such as ITO) mainly conducts electricity through oxygen vacancies, during the high-temperature annealing process, the oxygen in PZT will diffuse to the oxygen vacancies of ITO, causing the resistance of ITO to increase (the conductivity to decrease), which is not conducive to the device.
  • the first barrier layer 7 can block the diffusion of ions (such as O, Pb) in the piezoelectric film layer 3 to the first electrode layer 2 .
  • Electrode layer 2 so that when the piezoelectric film layer 3 is subsequently subjected to a high-temperature annealing process, the conductivity of ITO can be maintained while preventing Pb from diffusing into ITO, and it is easy to maintain the PZT perovskite crystal phase and increase the voltage of the piezoelectric film layer 3. electrical properties.
  • the first electrode layer may include a plurality of patterned first electrodes, or may be a whole-surface structure; the second electrode layer may include a plurality of patterned second electrodes.
  • the first electrode layer 2 and the second electrode layer 4 can be made of indium tin oxide (ITO), can also be made of indium zinc oxide (IZO), and of course can also be made of titanium gold ( Ti-Au) alloy, titanium aluminum titanium (Ti-Al-Ti) alloy, titanium molybdenum (Ti-Mo) alloy. In addition, it can also be made of titanium (Ti), gold (Au), silver It is made of one of (Ag), molybdenum (Mo), copper (Cu), tungsten (W), and chromium (Cr).
  • ITO indium tin oxide
  • IZO indium zinc oxide
  • Ti-Au titanium aluminum titanium
  • Ti-Mo titanium molybdenum
  • it can also be made of titanium (Ti), gold (Au), silver It is made of one of (Ag), molybdenum (Mo), copper (Cu), tungsten (W), and chromium (Cr).
  • Those skilled in the art can set the above-
  • the material of the first barrier layer 7 can be Ti. This is because Ti has stable characteristics and is not easily oxidized at high temperatures. metal, and the thickness is thin after the first barrier layer 7 is formed.
  • the thickness of the first barrier layer is less than 10nm, such as 9nm, 8nm, 7nm, 6nm, 5nm, 4nm, etc.
  • the transmittance of the first barrier layer 7 is greater than or equal to 60%, such as 60%, 70%, 80%, 90% %wait. In this way, when the piezoelectric sensor of the present disclosure is integrated into a display device, the display quality of the display device is not affected.
  • the material of the first barrier layer 7 may also include Pt, HfO 2 or LiNbO 3 , but is not limited thereto.
  • the first barrier layer 7 made of Ti can block most of the ions in PZT from diffusing to the first electrode layer 2, for example, the conductivity of the first electrode layer 2 and the conductivity of the piezoelectric film layer 3 can be further improved. Piezoelectric properties.
  • the above piezoelectric sensor provided by the embodiment of the present disclosure, as shown in Figure 3, it also includes a second barrier layer 8 located between the first barrier layer 7 and the piezoelectric film layer 3.
  • the second barrier layer The material of 8 is different from that of the first barrier layer 7 , and the second barrier layer 8 is used to further block the diffusion of ions in the piezoelectric film layer 3 to the first electrode layer 2 .
  • the material of the second barrier layer may be HfO 2 or LiNbO 3 .
  • HfO 2 when the material of the second barrier layer is HfO 2 , HfO 2 can be used as a seed layer.
  • the seed layer is required for film growth and orientation, so that the piezoelectric material is subsequently produced on the second barrier layer.
  • the crystallographic orientation of the piezoelectric material layer will be related to the orientation of the second barrier layer, which is beneficial to the crystallographic orientation of the piezoelectric material layer and improves the piezoelectric performance of the piezoelectric material layer.
  • LiNbO 3 when the material of the second barrier layer is LiNbO 3 (LNO for short), LiNbO 3 can also be used as a seed layer. Since LiNbO 3 itself is conductive, compared with HfO 2 , LiNbO 3 avoids the diffusion of Pb and O. At the same time, the conductivity can be further improved.
  • HfO 2 or LiNbO 3 can be selected as the second barrier layer according to actual needs.
  • the thickness of the second barrier layer is less than 50 nm, such as 40 nm, 30 nm, 20 nm, or 10 nm.
  • Figure 12 is a piezoelectric sensor structure in the related art, including a base substrate 1 and a first electrode layer 2, a piezoelectric film layer 3, and a second electrode layer that are stacked sequentially on the base substrate 1 4. Insulating layer 5 and wiring layer 6.
  • the wiring layer 6 is electrically connected to the second electrode layer 4 through a via hole penetrating the insulating layer 5; it also includes an insulation layer located on the side of the second electrode layer 4 facing away from the substrate 1 5.
  • the wiring layer 6 located on the side of the insulating layer 5 facing away from the base substrate 1; the wiring layer 6 is electrically connected to the second electrode layer 4 through a via hole penetrating the insulating layer 5, and the material of the insulating layer 5 is an inorganic material; One electrode layer 2 is connected to the ground, and the wiring layer 6 is connected to the driving signal terminal.
  • an insulating layer 5 needs to be provided between the second electrode layer 4 and the wiring layer 6 for isolation.
  • the manufacturing process of the piezoelectric thin film layer 3 (such as PZT material) generally includes dry etching and wet etching.
  • the piezoelectric film layer 3 includes a bottom edge aa disposed in contact with the first electrode layer 2 and a side edge bb adjacent to the bottom edge aa.
  • the piezoelectric film layer 3 is very easy to form a chamfered structure. (That is, the angle ⁇ is formed between the side bb and the first electrode layer 2), ⁇ is generally 60° to 85°; when using a dry etching process to make the piezoelectric film layer 3, the angle ⁇ between the side bb and the first electrode The angle ⁇ between layers 2 is generally 85° to 95°.
  • the embodiment of the present disclosure takes the wet etching process to produce the piezoelectric film layer 3 as an example, that is, the angle ⁇ between the side bb and the first electrode layer 2 is generally 60° to 85°. Since the inorganic insulating layer 5 used between the wiring layer 6 and the second electrode layer 4 in Figure 12 cannot fill the chamfered structure ( ⁇ ) of the piezoelectric film layer 3, it is easy to cause the risk of disconnection of the wiring layer 6, so As shown in FIG. 13 , an organic insulating layer 10 is used to fill the chamfer ( ⁇ ) of the piezoelectric film layer 3 between the wiring layer 6 and the second electrode layer 4 .
  • the piezoelectric sensor also includes:
  • the organic insulating layer 10 is located on the side of the second electrode layer 4 facing away from the base substrate 1.
  • the organic insulating layer 10 has a first via V1, and the orthographic projection of the first via V1 on the base substrate 1 is in contact with the second electrode layer. 4 Orthographic projections on the base substrate 1 overlap with each other;
  • the inorganic insulating layer 20 is located on the side of the organic insulating layer 10 facing away from the base substrate 1, and the inorganic insulating layer 20 does not at least partially overlap with the first via V1;
  • the wiring layer 6 is located on the side of the inorganic insulating layer 20 facing away from the base substrate 1 .
  • the wiring layer 6 includes wiring, and one end of the wiring is electrically connected to the second electrode layer 4 through at least part of the first via hole V1 .
  • the inorganic insulation layer 20 between the wiring layer 6 and the organic insulation layer 10. Due to the strong adhesion between the inorganic insulation layer 20 and the wiring layer 6, the organic insulation On the basis that the layer 10 solves the chamfering problem of the piezoelectric film layer 3, the inorganic insulating layer 20 can solve the problem of poor adhesion between the organic insulating layer 10 and the wiring layer 6, thereby preventing the wiring layer 6 from falling off. question.
  • the inorganic insulating layer 20 covers the sidewall of the first via V1 and extends to contact the second electrode layer 4 . Due to the influence of the manufacturing process, the cross-section of the first via V1 along the thickness direction of the piezoelectric sensor is generally an inverted trapezoidal structure.
  • the inorganic insulating layer 20 is disposed to cover the sidewall of the first via V1 and extends to the second electrode layer 4 In this way, the inorganic insulating layer 20 has a buffering effect in the first via hole V1, so that the wiring layer 6 produced later will not be disconnected at the first via hole V1.
  • the contact boundary between the inorganic insulating layer 20 and the second electrode layer 4 is the third One boundary
  • the contact boundary between the organic insulating layer 10 and the second electrode layer 4 is the second boundary
  • the distance d between the first boundary and the second boundary can be greater than 30% of the thickness of the piezoelectric film layer 3 and less than the piezoelectric film layer 3 60% of thickness.
  • the thickness of the piezoelectric film layer 3 is generally 1 ⁇ m to 10 ⁇ m, for example, the thickness of the piezoelectric film layer 3 is 1 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m or 10 ⁇ m.
  • the thickness of the piezoelectric film layer 3 is 3 ⁇ m, then d is greater than 0.9 ⁇ m and less than 1.8 ⁇ m; if the thickness of the piezoelectric film layer 3 is 6 ⁇ m, then d is greater than 1.8 ⁇ m and less than 3.6 ⁇ m; For example, if the thickness of the electrical thin film layer 3 is 9 ⁇ m, then d is greater than 2.7 ⁇ m and less than 5.4 ⁇ m; and so on.
  • the inorganic insulating layer 20 covers the side of the first via V1 wall and covers the second electrode layer 4 exposed by the first via hole V1.
  • the part of the inorganic insulating layer 20 covering the second electrode layer 4 has at least one second via hole V2, and one end of the trace (6) passes through the first via hole.
  • V1 and the second via hole V2 are electrically connected to the second electrode layer 4 .
  • part of the wiring layer 6 and the exposed second electrode layer 4 is in contact with the inorganic insulating layer 20 , and part of it is electrically connected to the second electrode layer 4 through the first via hole V1 and the second via hole V2. Since the wiring layer 6
  • the adhesion to the inorganic insulating layer 20 is strong, so the adhesion between the wiring layer 6 and the second electrode layer 4 can be improved on the basis of ensuring the electrical connection between the wiring layer 6 and the second electrode layer 4 sex.
  • the piezoelectric sensor provided by the embodiment of the present disclosure, as shown in Figures 4-7, it also includes: a binding electrode 30 arranged in the same layer as the first electrode layer 2, and the binding electrode 30 is close to The edge of the base substrate 1 is set, and the other end of the trace (6) is electrically connected to the binding electrode 30 through the third via V3 provided on the inorganic insulation layer 20 and the organic insulation layer 10.
  • the binding electrode 30 is used for connection. drive signal terminal. Specifically, a driving signal superimposed with a DC voltage and an AC voltage is loaded onto the second electrode layer 4 through the driving voltage input terminal, so that an alternating electric field can be formed between the first electrode layer 2 and the second electrode layer 4.
  • the alternating electric field The frequency is the same as that of the AC voltage signal. Under the action of the alternating electric field, the piezoelectric film layer 3 deforms and generates a vibration signal.
  • the frequency of the vibration signal is the same as the frequency of the alternating electric field.
  • the substrate The base substrate resonates, the amplitude increases, and a tactile feedback signal is generated.
  • the friction force on the surface of the substrate substrate can be adjusted through the resonance generated between the piezoelectric film layer and the substrate substrate, thereby achieving texture reproduction of the object on the surface of the substrate substrate.
  • the wiring layer is electrically connected to the second electrode layer 4 through the second via hole V2, as shown in Figures 14 and 15.
  • Figure 14 shows the second electrode layer 4 and the second electrode layer 4.
  • Figure 15 is an enlarged schematic diagram of the dotted box in Figure 14.
  • Piezoelectric sensors are generally combined with display devices to achieve tactile reproduction.
  • the wiring layer The shape of 6 can be a grid-like structure. Each grid line of the grid-like structure can be provided with a plurality of second via holes V2 corresponding to the inorganic insulation layer 20 below, so that the wiring layer 6 can be connected to the wiring layer 6 through the second via hole V2.
  • the second electrode layer 4 is electrically connected.
  • the material of the wiring layer can be Ti/Ni/Au, where Ti can be 10nm, Ni can be 400nm, and Au can be 100nm; or, the wiring layer The material of the layer can be Ti/Au, where Ti can be 10nm and Au can be 400nm; or the material of the wiring layer can be Ti/Al/Ti, where Ti can be 10nm and Al can be 300nm.
  • the number of inorganic insulating layers 20 may be one layer.
  • the material of the inorganic insulating layer 20 may include, but is not limited to, at least one of SiO 2 , Al 2 O 3 or Si 3 N 4 .
  • the inorganic insulating layer 20 may include at least two sub-insulating layers (21 and 22) arranged in a stack.
  • the materials of the insulating layers (21 and 22) are different.
  • the outermost sub-insulating layer 22 can be made of a material with good adhesion to the wiring layer 6 .
  • the material of each sub-insulating layer (21 and 22) may include but is not limited to SiO 2 , Al 2 O 3 or Si 3 N 4 .
  • the material of the wiring layer 6 is Cr, and the material of the outermost sub-insulating layer 22 can be Si 3 N 4 .
  • the thickness of the inorganic insulating layer 20 can be 100nm ⁇ 300nm.
  • the thickness of the inorganic insulating layer 20 can be 100nm, 200nm or 300nm.
  • the edge of the second electrode layer 4 may be indented relative to the edge of the piezoelectric film layer 3 .
  • the indentation amount of the edge of the second electrode layer 4 relative to the edge of the piezoelectric film layer 3 is greater than or equal to 100 micrometers and less than or equal to 500 micrometers.
  • the indentation may be 150 microns.
  • the edges of the piezoelectric film layer 3 may be recessed relative to the edges of the first electrode layer 2 .
  • Figure 2 provided by the embodiment of the present disclosure only provides the first barrier layer 7 on the basis of Figure 1
  • Figure 3 only provides the first barrier layer 7 and the second barrier layer 8 on the basis of Figure 1
  • Figures 4 to 7 show an inorganic insulating layer located between the organic insulating layer and the wiring layer based on Figure 13.
  • the arrangement of the barrier layer and the arrangement of the organic insulating layer and the inorganic insulating layer The setting scheme can be superimposed, that is, a first barrier layer and/or a second barrier layer can be placed between the first electrode layer and the piezoelectric film layer, and at the same time, an inorganic insulating layer and an organic layer can be placed between the second electrode layer and the wiring layer. Insulation layer, select and set according to actual needs.
  • the inventor of this case drove several piezoelectric sensors with different structures provided by embodiments of the present disclosure using the aforementioned driving method for piezoelectric sensors.
  • each film layer is: 500um/500nm/2000nm/250nm.
  • each film layer is: 500um/250nm/5-10nm/2000nm/250nm.
  • Glass/ITO/LNO/PZT/ITO the thickness of each film layer is: 500um/250um/100-200nm/2000nm/250nm.
  • each film layer is: 500um/250nm/100nm/2000nm/250nm.
  • each film layer is: 500um/10-20nm/2000nm/250nm.
  • Glass in each of the above structures represents the base substrate, the two ITOs represent the first electrode layer and the second electrode layer respectively, PZT represents the piezoelectric thin film layer, and Ti, LNO, Pt and HfO 2 all represent the first barrier layer.
  • Figure 16 is a vibration displacement-driving signal curve diagram of five kinds of piezoelectric sensors under different driving conditions. It can be seen that the second electrode layer provided by the embodiment of the present disclosure is loaded with signals superposed by DC voltage and AC voltage for driving voltage. For electrical sensors, the piezoelectric film layer can obtain larger vibration displacements, thereby improving the performance of the piezoelectric sensor.
  • making the piezoelectric sensor shown in Figure 4 may include the following steps:
  • a first electrode layer, a piezoelectric film material layer and a second electrode layer are sequentially formed on the base substrate;
  • the first electrode layer may include a plurality of patterned first electrodes, or may be a full-surface structure; the second electrode layer may include a plurality of patterned second electrodes.
  • the piezoelectric film material layer is polarized
  • a strong DC electric field is applied to the piezoelectric film material layer to form an orderly arrangement of Dipole moments in the piezoelectric film material layer, forming prepolarization characteristics.
  • the polarization is as follows: the first electrode layer is grounded (0V/GND), and the second electrode layer is loaded with DC voltage.
  • the DC voltage application process can be performed between room temperature and 120°C.
  • the DC voltage is >15V and the polarization time is >5min.
  • the polarized piezoelectric film material layer is patterned to form a piezoelectric film layer located between the first electrode layer and the second electrode layer;
  • the patterned piezoelectric thin film layer can be formed by dry coating (sputtering, Sputter) or wet coating (sol-gel method, Sol-Gel).
  • an organic insulating layer is formed on the side of the second electrode layer facing away from the base substrate.
  • the organic insulating layer has a first via hole.
  • the orthogonal projection of the first via hole on the base substrate is the same as the orthogonal projection of the second electrode layer on the base substrate. orthographic projections overlap each other;
  • an inorganic insulating layer is formed on a side of the organic insulating layer facing away from the base substrate, and the inorganic insulating layer does not at least partially overlap with the first via hole;
  • a wiring layer is formed on a side of the inorganic insulating layer facing away from the base substrate, and the wiring layer is electrically connected to the second electrode layer through at least part of the first via holes.
  • the piezoelectric film material layer needs to be polarized before forming the patterned piezoelectric film layer.
  • the piezoelectric sensor provided by the embodiment of the present disclosure can be applied to fields such as medical treatment, automotive electronics, and sports tracking systems. It is especially suitable for use in the field of wearable devices, monitoring and treatment outside medical devices or implanted inside the human body, or in fields such as artificial intelligence electronic skin. Specifically, piezoelectric sensors can be applied to brake pads, keyboards, mobile terminals, game controllers, vehicles and other devices that can produce vibration and mechanical properties.
  • an embodiment of the present disclosure also provides a tactile feedback device, including the above-mentioned piezoelectric sensor provided by an embodiment of the present disclosure. Since the problem-solving principle of the tactile feedback device is similar to that of the aforementioned piezoelectric sensor, the implementation of the tactile feedback device can refer to the implementation of the aforementioned piezoelectric sensor, and repeated details will not be repeated.
  • the tactile feedback device can be any product or component with display or touch functions such as mobile phones, tablet computers, televisions, monitors, notebook computers, digital photo frames, and navigators.
  • the above-mentioned tactile feedback device provided by the embodiments of the present disclosure may also include other functional structures well known to those skilled in the art, which will not be described in detail here.
  • the tactile feedback device can be combined with the touch screen, and the touch screen can determine the position of the human body's touch, thereby generating the corresponding vibration waveform, amplitude and frequency, and realizing human-computer interaction.
  • the piezoelectric sensor in the tactile feedback device determines the position of the human body's touch, thereby generating the corresponding vibration waveform, amplitude and frequency, which can realize human-computer interaction.
  • the tactile feedback device can also be applied in medical, automotive electronics, sports tracking systems and other fields according to actual needs, which will not be described in detail here.
  • Embodiments of the present disclosure provide a piezoelectric sensor, its driving method and a tactile feedback device.
  • a driving signal superimposed with a DC voltage and an AC voltage onto the second electrode layer of the piezoelectric sensor the DC voltage can cause the inside of the piezoelectric film layer to
  • the preferred orientation of the electric domain can overcome the stress inside the piezoelectric film layer, thereby overcoming the constraints of the substrate substrate, so that the piezoelectric film layer has a large vibration displacement driven by the driving signal superposed by DC voltage and AC voltage. This can improve the performance of piezoelectric sensors.

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Abstract

一种压电传感器、其驱动方法及触觉反馈装置，压电传感器包括：衬底基板（1），以及位于衬底基板（1）上的第一电极层（2）、压电薄膜层（3）和第二电极层（4）；其中，第一电极层（2）接地，第二电极层（4）耦接驱动信号端；驱动方法包括：向第一电极层（2）加载接地信号，向第二电极层（4）加载直流电压和交流电压叠加的驱动信号。

Description

压电传感器、其驱动方法及触觉反馈装置 技术领域
本公开涉及触觉反馈技术领域，特别涉及一种压电传感器、其驱动方法及触觉反馈装置。
背景技术
触觉反馈(Haptics)为现今科技开发的重点，具体地，触觉反馈能够透过触觉，使终端跟人体产生交互。触觉反馈又可以分为两类，一类为振动反馈，一类为触觉再现技术。
表面触觉再现技术可以通过裸指触控屏幕来感知物体特性，在多媒体终端实现高效自然的交互，具有巨大的研究价值，因而得到国内外研究学者的广泛关注。表面触觉物理意义上，为物体表面粗糙度与皮肤(指尖)的表面产生作用，因表面结构不同而形成不同的摩擦力。因此透过控制表面摩擦力，即可实现不同触觉/触感之模拟。
发明内容
本公开实施例提供了一种压电传感器、其驱动方法及触觉反馈装置，具体方案如下：
本公开实施例提供的一种压电传感器的驱动方法，所述压电传感器包括：衬底基板，以及位于所述衬底基板上的第一电极层、压电薄膜层和第二电极层；其中，所述第一电极层接地，所述第二电极层耦接驱动信号端；
所述驱动方法包括：向所述第一电极层加载接地信号，向所述第二电极层加载直流电压和交流电压叠加的驱动信号。
在一种可能的实现方式中，在本公开实施例提供的上述驱动方法中，所述压电薄膜层在所述第一电极层和所述第二电极层之间形成的交变电场的作 用下发生变形产生作用力，所述作用力满足如下公式：
F＝μ·[a 0+a 1sin(ωt)]·d 33；
其中，F为所述作用力，μ为系数，a 0为所述直流电压的电压值，a 1sin(ωt)为所述交流电压的电压值，a 1为所述驱动信号波形的峰值，d 33为压电常数。
在一种可能的实现方式中，在本公开实施例提供的上述驱动方法中，a 0大于0。
在一种可能的实现方式中，在本公开实施例提供的上述驱动方法中，a 0-|a 1|≥0。
在一种可能的实现方式中，在本公开实施例提供的上述驱动方法中，a 0＝|a 1|。
在一种可能的实现方式中，在本公开实施例提供的上述驱动方法中，所述衬底基板包括柔性衬底基板或玻璃衬底基板。
在一种可能的实现方式中，在本公开实施例提供的上述驱动方法中，所述压电薄膜层的厚度为1μm～10μm。
在一种可能的实现方式中，在本公开实施例提供的上述驱动方法中，所述压电薄膜层的致密度为95％～100％。
在一种可能的实现方式中，在本公开实施例提供的上述驱动方法中，所述压电薄膜层包括锆钛酸铅，所述锆钛酸铅中的原子数百分含量比值关系如下：
Pb/(Zr+Ti)＝0.9～1.1，Zr/(Zr+Ti)＝48％～53％。
在一种可能的实现方式中，在本公开实施例提供的上述驱动方法中，所述直流电压的电压值大于0。
在一种可能的实现方式中，在本公开实施例提供的上述驱动方法中，所述直流电压的电压值等于所述交流电压的峰值。
相应地，本公开实施例还提供了一种压电传感器，所述压电传感器采用本公开实施例提供的上述任一项所述的驱动方法进行驱动；所述压电传感器包括：衬底基板，以及位于所述衬底基板上的第一电极层、压电薄膜层和第 二电极层；其中，所述第一电极层接地，所述第二电极层耦接驱动信号端。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，还包括位于所述第一电极层和所述压电薄膜层之间的第一阻挡层，所述第一阻挡层用于阻挡所述压电薄膜层的离子扩散至所述第一电极层。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，所述第一阻挡层的材料为Ti。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，所述第一阻挡层的厚度小于10nm。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，所述第一阻挡层的透过率大于或等于60％。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，所述第一阻挡层的材料包括Pt、HfO 2或LiNbO 3。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，还包括位于所述第一阻挡层和所述压电薄膜层之间的第二阻挡层，所述第二阻挡层的材料与所述第一阻挡层的材料不同，所述第二阻挡层用于阻挡所述压电薄膜层的离子扩散至所述第一电极层。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，所述第二阻挡层的材料为HfO 2或LiNbO 3。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，所述第二阻挡层的厚度小于50nm。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，还包括：
有机绝缘层，位于所述第二电极层背离所述衬底基板的一侧，所述有机绝缘层具有第一过孔，所述第一过孔在所述衬底基板上的正投影与所述第二电极层在所述衬底基板上的正投影相互交叠；
无机绝缘层，位于所述有机绝缘层背离所述衬底基板的一侧，所述无机绝缘层与所述第一过孔至少部分不交叠；
走线层，位于所述无机绝缘层背离所述衬底基板的一侧，所述走线层包括走线，所述走线的一端通过至少部分所述第一过孔与所述第二电极层电连接。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，所述无机绝缘层覆盖所述第一过孔的侧壁且延伸至与所述第二电极层接触。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，在所述第一过孔的同一侧壁处，所述无机绝缘层和所述第二电极层的接触边界为第一边界，所述有机绝缘层和所述第二电极的接触边界为第二边界，所述第一边界和所述第二边界之间的距离大于所述压电薄膜层厚度的30％且小于所述压电薄膜层厚度的60％。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，所述无机绝缘层覆盖所述第一过孔的侧壁且覆盖所述第一过孔露出的第二电极层，所述无机绝缘层中覆盖所述第二电极层的部分具有至少一个第二过孔，所述走线的一端通过所述第一过孔和所述第二过孔与所述第二电极层电连接。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，还包括：与所述第一电极层同层设置的绑定电极，所述绑定电极靠近所述衬底基板的边缘设置，所述走线的另一端通过设置在所述无机绝缘层和所述有机绝缘层上的第三过孔与所述绑定电极电连接，所述绑定电极用于连接所述驱动信号端。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，所述无机绝缘层的数量为一层。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，所述无机绝缘层的材料包括SiO 2、Al 2O 3或Si 3N 4。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，所述无机绝缘层包括叠层设置的至少两个子层，所述两个子层的材料不同。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，各所述子层的材料包括SiO 2、Al 2O 3或Si 3N 4。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，所述走线层的形状为网格状结构，所述走线层的材料为Ti/Ni/Au、Ti/Au或Ti/Al/Ti。
在一种可能的实现方式中，在本公开实施例提供的上述压电传感器中，所述无机绝缘层的厚度为100nm～300nm。
相应地，本公开实施例还提供了一种触觉反馈装置，包括如本公开实施例提供的上述任一项所述的压电传感器。
附图说明
图1为相关技术中提供的一种压电传感器的结构示意图；
图2为本公开实施例提供的一种压电传感器的结构示意图；
图3为本公开实施例提供的又一种压电传感器的结构示意图；
图4为本公开实施例提供的又一种压电传感器的结构示意图；
图5为本公开实施例提供的又一种压电传感器的结构示意图；
图6为本公开实施例提供的又一种压电传感器的结构示意图；
图7为本公开实施例提供的又一种压电传感器的结构示意图；
图8为本公开实施例提供的一种驱动信号的示意图；
图9为本公开实施例提供的又一种驱动信号的示意图；
图10为本公开实施例提供的压电传感器的振动位移和第二电极层加载的驱动信号之间的关系曲线；
图11为压电传感器震动的效果示意图；
图12为相关技术中提供的一种压电传感器的结构示意图；
图13为相关技术中提供的又一种压电传感器的结构示意图；
图14为压电传感器中部分膜层的俯视示意图；
图15为图14中的局部放大示意图；
图16为5种压电传感器在不同驱动条件下的振动位移-驱动信号曲线图。
具体实施方式
为使本公开实施例的目的、技术方案和优点更加清楚，下面将结合本公开实施例的附图，对本公开实施例的技术方案进行清楚、完整地描述。显然，所描述的实施例是本公开的一部分实施例，而不是全部的实施例。并且在不冲突的情况下，本公开中的实施例及实施例中的特征可以相互组合。基于所描述的本公开的实施例，本领域普通技术人员在无需创造性劳动的前提下所获得的所有其他实施例，都属于本公开保护的范围。
除非另外定义，本公开使用的技术术语或者科学术语应当为本公开所属领域内具有一般技能的人士所理解的通常意义。本公开中使用的“包括”或者“包含”等类似的词语意指出现该词前面的元件或者物件涵盖出现在该词后面列举的元件或者物件及其等同，而不排除其他元件或者物件。“连接”或者“相连”等类似的词语并非限定于物理的或者机械的连接，而是可以包括电性的连接，不管是直接的还是间接的。“内”、“外”、“上”、“下”等仅用于表示相对位置关系，当被描述对象的绝对位置改变后，则该相对位置关系也可能相应地改变。
需要注意的是，附图中各图形的尺寸和形状不反映真实比例，目的只是示意说明本公开内容。并且自始至终相同或类似的标号表示相同或类似的元件或具有相同或类似功能的元件。
薄膜压电材料具有高介电常数与透明的特性，非常适合用于屏幕集成的传感器结构。其中，锆钛酸铅压电陶瓷(PZT)由于优异的压电性能，目前应用的较多。如图1所示，图1为PZT薄膜压电传感器的结构，包括衬底基板1以及位于衬底基板1上的第一电极层2、压电薄膜层3、第二电极层4、绝缘层5和走线层6，走线层6通过贯穿绝缘层5的过孔与第二电极层4电连接。压电薄膜层3的制作工艺为于第一电极层2上沉积，并于沉积后退火，由于第一电极层2的结晶取向与热膨胀系数的影响以及PZT热膨胀系数非定值，退火后压电薄膜层3内容易产生内应力。若压电薄膜层3沉积于第一电极层2(ITO)上，若压电薄膜层3晶化退火温度为500℃-700℃，考虑热膨胀系数 影响，回到室温后PZT/ITO介面上存在一张应力(箭头所示)。一般PZT薄膜压电传感器的驱动是第一电极层2加载接地信号，第二电极层4加载以对称信号中心在0V的正弦波信号进行驱动，由于PZT/ITO介面上的张应力大幅影响PZT薄膜压电传感器(致动器)运作，若第二电极层4仍然加载以对称信号中心在0V的正弦波信号，则PZT薄膜压电传感器无法有效工作。
有鉴于此，本公开实施例提供了一种压电传感器的驱动方法，如图2-图7所示，该压电传感器包括：衬底基板1，以及位于衬底基板1上的第一电极层2、压电薄膜层3和第二电极层4；其中，第一电极层2接地，第二电极层4耦接驱动信号端；
用于驱动图2-图7所示的压电传感器的驱动方法包括：向第一电极层2加载接地信号，向第二电极层4加载直流电压V dc和交流电压V dc叠加的驱动信号V，该驱动信号V如图8所示，V dc＝a 0，交流电压V AC的峰值为a 1。
本公开实施例提供的上述驱动方法，通过向压电传感器的第二电极层4加载直流电压V dc和交流电压V AC叠加的驱动信号V，直流电压V dc可以使压电薄膜层内部的电畴择优取向，可以克服压电薄膜层内部的应力，从而可以克服衬底基板1的束缚，使得压电薄膜层在直流电压V dc和交流电压V AC叠加的驱动信号V的驱动下具有较大的振动位移，从而可以提高压电传感器的性能。
需要说明的是，本公开实施例是以向靠近衬底基板1的第一电极层2加载接地信号，向远离衬底基板1的第二电极层4加载直流电压V dc和交流电压V dc叠加的驱动信号V为例，当然，在具体实施时，也可以向远离衬底基板1的第二电极层4加载接地信号，向靠近衬底基板1的第一电极层2加载直流电压V dc和交流电压V dc叠加的驱动信号V。
在具体实施时，本公开实施例提供的衬底基板1可以包括柔性衬底基板(例如PI等)或玻璃衬底基板。
当然，在具体实施过程中，衬底基板1还可以为由硅或二氧化硅(SiO 2)制成的基板，还可以为由蓝宝石制成的基板，还可以为由金属晶圆制成的基 板，在此不做限定，本领域技术人员可以根据实际应用需要来设置所述衬底基板1。
在具体实施时，本公开实施例提供的压电薄膜层3的制作工艺可以是气相沉积工艺(CVD)、溅射工艺(Sputter)或溶胶-凝胶法工艺(Sol-Gel)。
在具体实施时，本公开实施例提供的压电薄膜层3的厚度可以为1μm～10μm。
在具体实施时，本公开实施例提供的压电薄膜层3的致密度为95％～100％。
在具体实施时，本公开实施例提供的压电薄膜层3的材料可以包括锆钛酸铅(Pb(Zr,Ti)O 3，PZT)，锆钛酸铅中的原子数百分含量比值关系如下：
Pb/(Zr+Ti)＝0.9～1.1，Zr/(Zr+Ti)＝48％～53％。这样形成的压电薄膜层3具有优异的高压电系数，保证了相应的压电传感器的压电特性。
在具体实施时，压电薄膜层3不限于是上述所说的PZT，还可以是氮化铝(AlN)、ZnO(氧化锌)、钛酸钡(BaTiO 3)、钛酸铅(PbTiO 3)、铌酸钾(KNbO 3)、铌酸锂(LiNbO 3)、钽酸锂(LiTaO 3)、硅酸镓镧(La 3Ga 5SiO 14)中的至少一种，具体可以根据本领域技术人员的实际使用需要来选择制作压电薄膜层的材料，在此不做限定。其中，在使用PZT制成压电薄膜层时，由于PZT具有高压电系数，保证了相应的压电传感器的压电特性，可以将相应的压电传感器应用到触觉反馈器件中，而且PZT具有较高的透光性，在将其集成到显示器件中时，不影响显示器件的显示质量。
在具体实施时，在本公开实施例提供的上述驱动方法中，如图2-图7所示，由于向第一电极层2加载接地信号，向第二电极层4加载直流电压V dc和交流电压V dc叠加的驱动信号V，因此在第一电极层2和第二电极层4之间形成交变电场，压电薄膜层3在第一电极层2和第二电极层4之间形成的交变电场的作用下发生变形产生作用力F，作用力F满足如下公式：
F＝μ·[a 0+a 1sin(ωt)]·d 33；
其中，μ为系数，a 0为上述加载的直流电压的电压值，a 1sin(ωt)为上述加载的交流电压的电压值，a 1为驱动信号波形的峰值，d 33为压电常数。
具体地，可以根据用户需要的触觉反馈效果来确定作用力F，然后根据该作用力F确定需要给第二电极层4加载的驱动信号V，从而确定a 0和a 1。
具体地，驱动信号波形(一般为正弦形状的波形)的峰值是以0刻度为基准的最大值，有正有负。驱动信号波形的峰峰值是最大值和最小值的差值，只有正的。峰峰值描述了信号值的变化范围的大小。峰峰值与峰值的关系：峰值是指一个周期内信号最高值或最低值到平均值之间差的值。一般来说，峰值对上下对称的信号才有定义。即峰值等于峰峰值的一半。
在具体实施时，在本公开实施例提供的上述驱动方法中，如图8所示，直流电压V dc的电压值a 0大于0。相比于相关技术中只对第二电极层4加载交流电压信号，本公开实施例提供的驱动方法可以使压电薄膜层3内部的电畴择优取向，可以克服压电薄膜层3内部的应力，使得压电薄膜层3在直流电压V dc和交流电压V AC叠加的驱动信号V的驱动下具有较大的振动位移，提高压电传感器的性能。
在具体实施时，为了进一步提高压电薄膜层的振动位移，在本公开实施例提供的上述驱动方法中，直流电压V dc的电压值a0满足：a 0-|a 1|≥0。
在具体实施时，在本公开实施例提供的上述驱动方法中，如图9所示，直流电压V dc的电压值a 0和交流电压V AC的峰值a 1满足a 0＝|a 1|时，可以使得压电传感器获得最佳驱动效果，压电薄膜层3的振动位移最大。
如图10所示，图10为本公开实施例提供的压电传感器的振动位移(nm)和第二电极层加载的驱动信号(V)之间的关系曲线，其中，V PP(Voltage Peak-Peak)为峰峰值电压。本公开实施例中的V PP＝2a 1＝2a 0时，压电薄膜层3的振动位移较大。从图10可以看出，A点表示仅向第二电极层4加载交流电压信号，B点表示同时向第二电极层4加载直流电压为5V和交流电压信号(V PP＝10V)的驱动信号，C点表示同时向第二电极层4加载直流电压为5V和交流电压信号(V PP＝14V)的驱动信号，D点表示同时向第二电极层4加载直流电压为8V和交流电压信号(V PP＝16V)的驱动信号，E点表示同时向第二电极层4加载直流电压为10V和交流电压信号(V PP＝20V)的驱动信号，F点 表示同时向第二电极层4加载直流电压为12V和交流电压信号(V PP＝24V)的驱动信号，其中，B、D、E、F都是a 0＝a 1时，压电薄膜层的振动位移变化，可以看出相比于A点只加载交流电压，B、D、E、F对应的压电薄膜层具有较大的振动位移。其中B和C的振动位移没有变化，是因为C点对应的a 0小于a 1，因此只有当a 0＝a 1时，压电薄膜层具有较大的振动位移，如图11所示，图11为激光测振得到的压电传感器的振动效果示意图。
综上所述，本公开实施例通过向第二电极层同时加载直流电压和交流电压叠加的驱动信号，且当直流电压的电压值等于交流电压V AC的峰值a 1时，压电薄膜层具有较大的振动位移，从而提高压电传感器的性能。
下面对本公开实施例提供的压电传感器的具体结构进行说明：
本公开实施例提供的一种压电传感器，如图2-图7所示，该压电传感器采用前述的一种压电传感器的驱动方法进行驱动，可以使得压电传感器具有较大的振动位移；该压电传感器包括：衬底基板1，以及位于衬底基板1上的第一电极层2、压电薄膜层3和第二电极层4；其中，第一电极层2接地，第二电极层4耦接驱动信号端。
制作压电薄膜层(PZT)的工艺方法有很多，包括干法镀膜(溅射，Sputter)与湿法镀膜(溶胶-凝胶法，Sol-Gel)，但若要实现良好压电常数特性，PZT材料需要经过高温退火工艺，此工艺需在550℃-650℃空气环境下进行PZT晶粒生长，形成良好的固溶相。将振动器结构集成到显示器件中时，为了不影响显示器件的显示质量，振动器结构需使用透明电极(如ITO)作为基底电极与生长层，但存在如下问题：一方面，因ITO主要通过氧空缺进行导电，但PZT为钙钛矿相且需足够的晶粒尺寸形成压电性能，因此PZT需要高温氧气退火，此退火工艺会导致ITO阻值大幅上升，线路电阻上升，导电度下降，不利于器件高频驱动。另外，因PZT中的Pb离子具有很小的离子半径，很容易在氧化物间产生扩散，一旦PZT薄膜直接制作于ITO上，在不同高温退火工艺下，经本案的发明人验证，Pb离子均具有100nm左右的扩散，此扩散除导致ITO电阻上升，也将导致PZT膜层产生Pb离子缺失，使钙钛矿相态转往Pyrochlore 相态，降低PZT的压电性能，从而降低压电器件性能。因此，在本公开实施例提供的上述压电传感器中，如图2所示，还包括位于第一电极层2和压电薄膜层3之间的第一阻挡层7，第一阻挡层7用于阻挡压电薄膜层3的离子扩散至第一电极层2。
本发明实施例提供的上述压电传感器，由于压电薄膜层3(例如PZT)可以采用干法镀膜或湿法镀膜的方式形成，但若要实现良好压电常数特性，PZT材料需要经过高温退火工艺，此工艺需在550℃-650℃空气环境下进行PZT晶粒生长，形成良好的固溶相。因第一电极层2(例如ITO)主要通过氧空缺进行导电，在高温退火工艺中，PZT中的氧会扩散至ITO的氧空缺位置，导致ITO电阻上升(导电度下降)，从而不利于器件高频驱动；并且用于Pb离子半径较小，Pb离子很容易在氧化物间扩散，此扩散除导致ITO电阻上升，也将导致PZT膜层产生Pb离子缺失，使相态转往Pyrochlore，从而降低PZT的压电性能。本公开实施例通过在压电薄膜层3和第一电极层2之间设置第一阻挡层7，第一阻挡层7可以阻挡压电薄膜层3的离子(例如O、Pb)扩散至第一电极层2，从而后续对压电薄膜层3采用高温退火工艺时，可以保持ITO导电度的同时，避免Pb扩散进ITO，并易于维持PZT钙钛矿结晶相，提高压电薄膜层3的压电性能。
需要说明的是，第一电极层可以包括图案化的多个第一电极，也可以为一整面的结构；第二电极层包括图案化的多个第二电极。
在具体实施过程中，第一电极层2和第二电极层4可以是由氧化铟锡(ITO)制成，还可以是由氧化铟锌(IZO)制成，当然还可以是由钛金(Ti-Au)合金、钛铝钛(Ti-Al-Ti)合金、钛钼(Ti-Mo)合金中的一种制成，此外，还可以是由钛(Ti)、金(Au)、银(Ag)、钼(Mo)、铜(Cu)、钨(W)、铬(Cr)中的一种制成，本领域技术人员可以根据实际应用需要来设置上述第一电极层和第二电极层，在此不做限定。
在具体实施时，在本公开实施例提供的上述压电传感器中，如图2所示，第一阻挡层7的材料可以为Ti，这是由于Ti的特性稳定，其为在高温下不易 氧化的金属，并且形成第一阻挡层7后厚度较薄。
在具体实施时，为了保证压电传感器的透明性，在本公开实施例提供的上述压电传感器中，第一阻挡层的厚度小于10nm，例如9nm、8nm、7nm、6nm、5nm、4nm等。
在具体实施时，在本公开实施例提供的上述压电传感器中，如图2所示，第一阻挡层7的透过率大于或等于60％，例如60％、70％、80％、90％等。这样将本公开的压电传感器集成到显示器件中时，不影响显示器件的显示质量。
在具体实施时，在本公开实施例提供的上述压电传感器中，如图2所示，第一阻挡层7的材料还可以包括Pt、HfO 2或LiNbO 3，但不限于此。
在具体实施时，虽然采用Ti制作的第一阻挡层7可以阻挡PZT中大部分离子扩散至第一电极层2，但是为例进一步提高第一电极层2的导电度以及压电薄膜层3的压电性能，在本公开实施例提供的上述压电传感器中，如图3所示，还包括位于第一阻挡层7和压电薄膜层3之间的第二阻挡层8，第二阻挡层8的材料与第一阻挡层7的材料不同，第二阻挡层8用于进一步阻挡压电薄膜层3的离子扩散至第一电极层2。
在具体实施时，在本公开实施例提供的上述压电传感器中，第二阻挡层的材料可以为HfO 2或LiNbO 3。
具体地，第二阻挡层的材料为HfO 2时，HfO 2可以作为种子层(seed layer)，薄膜生长，若要有取向，都需种子层，这样后续在第二阻挡层上制作压电材料层时，压电材料层生长的结晶取向会与第二阻挡层的取向相关，从而有利于压电材料层生长的结晶取向，提高压电材料层的压电性能。
具体地，第二阻挡层的材料为LiNbO 3(简称LNO)时，LiNbO 3也可以作为种子层(seed layer)，由于LiNbO 3本身导电，相比于HfO 2，LiNbO 3在避免Pb、O扩散的同时，可以更进一步提升导电度。
在采用干法或湿法工艺制作压电材料层(如PZT)时，工艺中多多少少都会有微孔，一旦PZT中有孔洞，第一电极层和第二电极层连接，形成短路， 由于LNO为导体，因此使用HfO 2作为第二阻挡层，较LNO作为第二阻挡层，更能抵御PZT层产生孔洞时，通过HfO 2的绝缘性，避免第一电极层和第二电极层短路的问题。
因此，可以根据实际需要选择HfO 2或LiNbO 3作为第二阻挡层。
在具体实施时，在本公开实施例提供的上述压电传感器中，第二阻挡层的厚度小于50nm，例如40nm、30nm、20nm、10nm。
如图12所示，图12为相关技术中的压电传感器结构，包括衬底基板1以及位于衬底基板1上依次层叠设置的第一电极层2、压电薄膜层3、第二电极层4、绝缘层5和走线层6，走线层6通过贯穿绝缘层5的过孔与第二电极层4电连接；还包括位于第二电极层4背离衬底基板1一侧的绝缘层5，位于绝缘层5背离衬底基板1一侧的走线层6；走线层6通过贯穿绝缘层5的过孔与第二电极层4电连接，绝缘层5的材料为无机材料；第一电极层2接地，走线层6接驱动信号端。由于为避免短路问题，第二电极层4与走线层6之间需要设置绝缘层5隔离，但压电薄膜层3(例如PZT材料)的制作工艺一般包括干法刻蚀和湿法刻蚀，压电薄膜层3包括与第一电极层2接触设置的底边aa以及与底边aa邻接的侧边bb，在采用湿法刻蚀工艺时，压电薄膜层3非常容易形成倒角结构(即侧边bb与第一电极层2之间形成夹角θ)，θ一般为60°～85°；在采用干法刻蚀工艺制作压电薄膜层3时，侧边bb与第一电极层2之间的夹角θ一般为85°～95°。需要说明的是，本公开实施例是以采用湿法刻蚀工艺制作压电薄膜层3为例，即侧边bb与第一电极层2之间的夹角θ一般为60°～85°。由于图12中在走线层6和第二电极层4之间采用无机的绝缘层5无法填充压电薄膜层3的倒角结构(θ)，容易导致走线层6断线的风险，因此如图13所示，在走线层6和第二电极层4之间采用有机的绝缘层10填充压电薄膜层3的倒角(θ)。但是由于有机绝缘层10和走线层6之间的粘附性不佳容易导致走线层6脱落(如图13所示)。因此，在具体实施时，在本公开实施例提供的上述压电传感器中，如图4-图7所示，压电传感器还包括：
有机绝缘层10，位于第二电极层4背离衬底基板1的一侧，有机绝缘层10具有第一过孔V1，第一过孔V1在衬底基板1上的正投影与第二电极层4在衬底基板1上的正投影相互交叠；
无机绝缘层20，位于有机绝缘层10背离衬底基板1的一侧，无机绝缘层20与第一过孔V1至少部分不交叠；
走线层6，位于无机绝缘层20背离衬底基板1的一侧，走线层6包括走线，走线的一端通过至少部分第一过孔V1与第二电极层4电连接。
本公开实施例图4-图7通过在走线层6和有机绝缘层10之间设置无机绝缘层20，由于无机绝缘层20与走线层6之间的粘附性较强，在有机绝缘层10解决压电薄膜层3的倒角问题的基础上，无机绝缘层20可以解决有机绝缘层10与走线层6之间粘附性不佳的问题，从而可以防止走线层6脱落的问题。
在具体实施时，在本公开实施例提供的上述压电传感器中，如图4和图6所示，无机绝缘层20覆盖第一过孔V1的侧壁且延伸至与第二电极层4接触。由于制作工艺的影响，第一过孔V1沿压电传感器厚度方向的截面一般为倒梯形结构，将无机绝缘层20设置成覆盖第一过孔V1的侧壁且延伸至与第二电极层4接触，这样无机绝缘层20在第一过孔V1内具有缓冲作用，使得后续制作的走线层6在第一过孔V1处不会发生断线的问题。
在具体实施时，在本公开实施例提供的上述压电传感器中，如图4和图6所示，在第一过孔V1处，无机绝缘层20和第二电极层4的接触边界为第一边界，有机绝缘层10和第二电极层4的接触边界为第二边界，第一边界和第二边界之间的距离d可以大于压电薄膜层3厚度的30％且小于压电薄膜层3厚度的60％。具体地，由于压电薄膜层3的厚度一般为1μm～10μm，例如，压电薄膜层3的厚度为1μm、2μm、3μm、4μm、5μm、6μm、7μm、8μm、9μm或10μm。例如，以压电薄膜层3的厚度为3μm为例，则d大于0.9μm且小于1.8μm；以压电薄膜层3的厚度为6μm为例，则d大于1.8μm且小于3.6μm；以压电薄膜层3的厚度为9μm为例，则d大于2.7μm且小于5.4μm；等等。
在具体实施时，由于走线层的材料一般为金属材料，第二电极层的材料一般为氧化铟锡(ITO)，金属与ITO之间的粘附性不佳，为了防止走线层与第二电极层之间发生剥离导致无法进行电信号传输的问题，在本公开实施例提供的上述压电传感器中，如图5和图7所示，无机绝缘层20覆盖第一过孔V1的侧壁且覆盖第一过孔V1露出的第二电极层4，无机绝缘层20中覆盖第二电极层4的部分具有至少一个第二过孔V2，走线(6)的一端通过第一过孔V1和第二过孔V2与第二电极层4电连接。这样走线层6与露出的第二电极层4之间部分与无机绝缘层20接触，部分通过第一过孔V1和第二过孔V2与第二电极层4电连接，由于走线层6与无机绝缘层20之间的粘附性较强，因此可以在保证走线层6与第二电极层4电连接的基础上，提高走线层6与第二电极层4之间的粘附性。
在具体实施时，在本公开实施例提供的上述压电传感器中，如图4-图7所示，还包括：与第一电极层2同层设置的绑定电极30，绑定电极30靠近衬底基板1的边缘设置，走线(6)的另一端通过设置在无机绝缘层20和有机绝缘层10上的第三过孔V3与绑定电极30电连接，绑定电极30用于连接驱动信号端。具体地，通过驱动电压输入端向第二电极层4加载直流电压和交流电压叠加的驱动信号，这样在第一电极层2和第二电极层4之间可以形成交变电场，交变电场的频率与交流电压信号的频率相同。在交变电场的作用下，压电薄膜层3发生形变并产生振动信号，该振动信号的频率与交变电场的频率相同，当振动信号的频率接近或等于衬底基板的固有频率时，衬底基板发生共振，振幅增强，产生触觉反馈信号，当手指触摸衬底基板的表面时，可以明显感受到摩擦力的变化。在实际应用中，可以通过压电薄膜层与衬底基板之间产生的共振来调节衬底基板表面的摩擦力，从而在衬底基板的表面实现物体的纹理再现。
在具体实施时，为了更清楚的示意图5中走线层通过第二过孔V2与第二电极层4电连接，如图14和图15所示，图14为第二电极层4、第二过孔V2和走线层6的俯视示意图，图15为图14中虚线框内的放大示意图，压电传 感器一般与显示器件结合实现触觉再现，为了提高压电传感器的透过率，走线层6的形状可以为网格状结构，网格状结构的每一条网格线对应下方的无机绝缘层20可以设置多个第二过孔V2，以实现走线层6通过第二过孔V2与第二电极层4电连接。
在具体实施时，在本公开实施例提供的上述振动面板中，走线层的材料可以为Ti/Ni/Au，其中Ti可以为10nm，Ni可以为400nm，Au可以为100nm；或，走线层的材料可以为Ti/Au，其中Ti可以为10nm，Au可以为400nm；或，走线层的材料可以为Ti/Al/Ti，其中Ti可以为10nm，Al可以为300nm。
在具体实施时，在本公开实施例提供的上述压电传感器中，如图4和图5所示，无机绝缘层20的数量可以为一层。具体地，无机绝缘层20的材料可以包括但不限于SiO 2、Al 2O 3或Si 3N 4中的至少一种。
在具体实施时，在本公开实施例提供的上述触控面板中，如图6和图7所示，无机绝缘层20可以包括叠层设置的至少两个子绝缘层(21和22)，两个子绝缘层(21和22)的材料不同。这样可以根据走线层6的材料，将最外侧的子绝缘层22的材料采用与走线层6的粘附性较好的材料。具体地，各子绝缘层(21和22)的材料可以包括但不限于SiO 2、Al 2O 3或Si 3N 4。例如走线层6的材料为Cr，则最外侧的子绝缘层22的材料可以为Si 3N 4。
在具体实施时，在本公开实施例提供的上述振动面板中，如图4-图7所示，无机绝缘层20的厚度可以为100nm～300nm，例如无机绝缘层20的厚度为100nm、200nm或300nm。
为了降低短路风险，参照图2-图7，第二电极层4的边缘可以相对于压电薄膜层3的边缘缩进。在具体实现中，第二电极层4的边缘相对于压电薄膜层3的边缘的缩进量大于或等于100微米，且小于或等于500微米。例如，缩进量可以为150微米。
为了进一步降低短路风险，压电薄膜层3的边缘可以相对于第一电极层2的边缘缩进。
需要说明的是，本公开实施例提供的图2仅是在图1的基础上设置第一 阻挡层7，图3仅是在图1的基础上设置第一阻挡层7和第二阻挡层8，图4-图7是在图13的基础上设置位于有机绝缘层和走线层之间的无机绝缘层，当然，在具体实施时，阻挡层的设置方案和有机绝缘层、无机绝缘层的设置方案可以叠加，即在第一电极层和压电薄膜层之间可以设置第一阻挡层和/或第二阻挡层，同时在第二电极层和走线层之间设置无机绝缘层和有机绝缘层，根据实际需要进行选择设置。
本案的发明人对本公开实施例提供的几种不同结构的压电传感器采用前述一种压电传感器的驱动方法进行了驱动。
本公开实施例提供的五种压电传感器的结构为：
1、Glass/ITO/PZT/ITO，各膜层的厚度为：500um/500nm/2000nm/250nm。
2、Glass/ITO/Ti/PZT/ITO，各膜层的厚度为：500um/250nm/5-10nm/2000nm/250nm。
3、Glass/ITO/LNO/PZT/ITO，各膜层的厚度为：500um/250um/100-200nm/2000nm/250nm。
4、Glass/ITO/Pt/PZT/ITO，各膜层的厚度为：500um/250nm/100nm/2000nm/250nm。
5、Glass/ITO/HfO 2/PZT/ITO，各膜层的厚度为：500um/10-20nm/2000nm/250nm。
上述各结构中的Glass表示衬底基板，两个ITO分别表示第一电极层和第二电极层，PZT表示压电薄膜层，Ti、LNO、Pt和HfO 2均表示第一阻挡层。
在对上述五种压电传感器进行驱动时，第一电极层接地，第二电极层均加载直流电压和交流电压叠加的信号，且直流电压的电压值等于交流电压的峰值，如图16所示，图16为5种压电传感器在不同驱动条件下的振动位移-驱动信号曲线图，可以看出采用本公开实施例提供的第二电极层均加载直流电压和交流电压叠加的信号进行驱动压电传感器，压电薄膜层可以获得较大的振动位移，从而提高压电传感器的性能。
示例性的，以本公开实施例提供的图4的压电传感器为例，制作图4所 示的压电传感器，可以包括以下步骤：
首先，在衬底基板上依次形成第一电极层、压电薄膜材料层和第二电极层；
具体地，第一电极层可以包括图案化的多个第一电极，也可以为一整面的结构；第二电极层包括图案化的多个第二电极。
其次，对压电薄膜材料层进行极化处理；
具体地，在压电薄膜材料层上加一强直流电场，使压电薄膜材料层中Dipole moment(偶极矩)形成有序排列，形成预极化特性。一般极化为第一电极层接地(0V/GND)，第二电极层加载直流电压，可于室温～120℃间进行加直流电压过程，直流电压为>15V，极化时间>5min。通过极化工艺，可进一步提升PZT移动薄膜层的性能。
接着，对极化处理后的压电薄膜材料层进行图案化，形成位于第一电极层和第二电极层之间的压电薄膜层；
具体地，可以采用干法镀膜(溅射，Sputter)或湿法镀膜(溶胶-凝胶法，Sol-Gel)的方式形成图案化的压电薄膜层。
接着，在第二电极层背离衬底基板的一侧形成有机绝缘层，有机绝缘层具有第一过孔，第一过孔在衬底基板上的正投影与第二电极层在衬底基板上的正投影相互交叠；
接着，在有机绝缘层背离衬底基板的一侧形成无机绝缘层，无机绝缘层与第一过孔至少部分不交叠；
接着，在无机绝缘层背离衬底基板的一侧形成走线层，走线层通过至少部分第一过孔与第二电极层电连接。
需要说明的是，在制作本公开实施例提供的其它压电传感器的结构时，在形成图案化的压电薄膜层之前，均需对压电薄膜材料层进行极化处理。
本公开实施例提供的压电传感器可应用于医疗，汽车电子，运动追踪系统等领域。尤其适用于可穿戴设备领域，医疗体外或植入人体内部的监测及治疗使用，或者应用于人工智能的电子皮肤等领域。具体地，可以将压电传 感器应用于刹车片、键盘、移动终端、游戏手柄、车载等可产生振动和力学特性的装置中。
基于同一发明构思，本公开实施例还提供了一种触觉反馈装置，包括本公开实施例提供的上述压电传感器。由于该触觉反馈装置解决问题的原理与前述一种压电传感器相似，因此该触觉反馈装置的实施可以参见前述压电传感器的实施，重复之处不再赘述。该触觉反馈装置可以为：手机、平板电脑、电视机、显示器、笔记本电脑、数码相框、导航仪等任何具有显示或触控功能的产品或部件。
在具体实施时，本公开实施例提供的上述触觉反馈装置还可以包括本领域技术人员熟知的其他功能结构，在此不做详述。
在具体实施时，可以将触觉反馈装置与触控屏在一起，通过触控屏可以确定人体触控的位置，从而产生对应的振动波形、振幅和频率，可以实现人机交互。再比如，通过触觉反馈装置中的压电传感器确定人体触控的位置，从而产生对应的振动波形、振幅和频率，可以实现人机交互。当然，还可以根据实际需要将触觉反馈装置应用在医疗，汽车电子，运动追踪系统等领域，在此不再详述。
本公开实施例提供了一种压电传感器、其驱动方法及触觉反馈装置，通过向压电传感器的第二电极层加载直流电压和交流电压叠加的驱动信号，直流电压可以使压电薄膜层内部的电畴择优取向，可以克服压电薄膜层内部的应力，从而可以克服衬底基板的束缚，使得压电薄膜层在直流电压和交流电压叠加的驱动信号的驱动下具有较大的振动位移，从而可以提高压电传感器的性能。
尽管已描述了本公开的优选实施例，但本领域内的技术人员一旦得知了基本创造性概念，则可对这些实施例作出另外的变更和修改。所以，所附权利要求意欲解释为包括优选实施例以及落入本公开范围的所有变更和修改。
显然，本领域的技术人员可以对本公开实施例进行各种改动和变型而不脱离本公开实施例的精神和范围。这样，倘若本公开实施例的这些修改和变 型属于本公开权利要求及其等同技术的范围之内，则本公开也意图包含这些改动和变型在内。

Claims (30)

  1. 一种压电传感器的驱动方法，其中，所述压电传感器包括：衬底基板，以及位于所述衬底基板上的第一电极层、压电薄膜层和第二电极层；其中，所述第一电极层接地，所述第二电极层耦接驱动信号端；
    所述驱动方法包括：向所述第一电极层加载接地信号，向所述第二电极层加载直流电压和交流电压叠加的驱动信号。
  2. 如权利要求1所述的驱动方法，其中，所述压电薄膜层在所述第一电极层和所述第二电极层之间形成的交变电场的作用下发生变形产生作用力，所述作用力满足如下公式：
    F＝μ·[a 0+a 1sin(ωt)]·d 33；
    其中，F为所述作用力，μ为系数，a 0为所述直流电压的电压值，a 1sin(ωt)为所述交流电压的电压值，a 1为所述驱动信号波形的峰值，d 33为压电常数。
  3. 如权利要求2所述的驱动方法，其中，a 0大于0。
  4. 如权利要求3所述的驱动方法，其中，a 0-|a 1|≥0。
  5. 如权利要求4所述的驱动方法，其中，a 0＝|a 1|。
  6. 如权利要求1-5任一项所述的驱动方法，其中，所述衬底基板包括柔性衬底基板或玻璃衬底基板。
  7. 如权利要求1-6任一项所述的驱动方法，其中，所述压电薄膜层的厚度为1μm～10μm。
  8. 如权利要求1-7任一项所述的驱动方法，其中，所述压电薄膜层的致密度为95％～100％。
  9. 如权利要求1-8任一项所述的驱动方法，其中，所述压电薄膜层包括锆钛酸铅，所述锆钛酸铅中的原子数百分含量比值关系如下：
    Pb/(Zr+Ti)＝0.9～1.1，Zr/(Zr+Ti)＝48％～53％。
  10. 一种压电传感器，其中，所述压电传感器采用如权利要求1-9任一项所述的驱动方法进行驱动；所述压电传感器包括：衬底基板，以及位于所述 衬底基板上的第一电极层、压电薄膜层和第二电极层；其中，所述第一电极层接地，所述第二电极层耦接驱动信号端。
  11. 如权利要求10所述的压电传感器，其中，还包括位于所述第一电极层和所述压电薄膜层之间的第一阻挡层，所述第一阻挡层用于阻挡所述压电薄膜层的离子扩散至所述第一电极层。
  12. 如权利要求11所述的压电传感器，其中，所述第一阻挡层的材料为Ti。
  13. 如权利要求12所述的压电传感器，其中，所述第一阻挡层的厚度小于10nm。
  14. 如权利要求12所述的压电传感器，其中，所述第一阻挡层的透过率大于或等于60％。
  15. 如权利要求11所述的压电传感器，其中，所述第一阻挡层的材料包括Pt、HfO 2或LiNbO 3。
  16. 如权利要求12所述的压电传感器，其中，还包括位于所述第一阻挡层和所述压电薄膜层之间的第二阻挡层，所述第二阻挡层的材料与所述第一阻挡层的材料不同，所述第二阻挡层用于阻挡所述压电薄膜层的离子扩散至所述第一电极层。
  17. 如权利要求16所述的压电传感器，其中，所述第二阻挡层的材料为HfO 2或LiNbO 3。
  18. 如权利要求17所述的压电传感器，其中，所述第二阻挡层的厚度小于50nm。
  19. 如权利要求10-18任一项所述的压电传感器，其中，还包括：
    有机绝缘层，位于所述第二电极层背离所述衬底基板的一侧，所述有机绝缘层具有第一过孔，所述第一过孔在所述衬底基板上的正投影与所述第二电极层在所述衬底基板上的正投影相互交叠；
    无机绝缘层，位于所述有机绝缘层背离所述衬底基板的一侧，所述无机绝缘层与所述第一过孔至少部分不交叠；
    走线层，位于所述无机绝缘层背离所述衬底基板的一侧，所述走线层包括走线，所述走线的一端通过至少部分所述第一过孔与所述第二电极层电连接。
  20. 如权利要求19所述的压电传感器，其中，所述无机绝缘层覆盖所述第一过孔的侧壁且延伸至与所述第二电极层接触。
  21. 如权利要求20所述的压电传感器，其中，在所述第一过孔的同一侧壁处，所述无机绝缘层和所述第二电极层的接触边界为第一边界，所述有机绝缘层和所述第二电极的接触边界为第二边界，所述第一边界和所述第二边界之间的距离大于所述压电薄膜层厚度的30％且小于所述压电薄膜层厚度的60％。
  22. 如权利要求19所述的压电传感器，其中，所述无机绝缘层覆盖所述第一过孔的侧壁且覆盖所述第一过孔露出的第二电极层，所述无机绝缘层中覆盖所述第二电极层的部分具有至少一个第二过孔，所述走线的一端通过所述第一过孔和所述第二过孔与所述第二电极层电连接。
  23. 如权利要求20-22任一项所述的压电传感器，其中，还包括：与所述第一电极层同层设置的绑定电极，所述绑定电极靠近所述衬底基板的边缘设置，所述走线的另一端通过设置在所述无机绝缘层和所述有机绝缘层上的第三过孔与所述绑定电极电连接，所述绑定电极用于连接所述驱动信号端。
  24. 如权利要求19-23任一项所述的压电传感器，其中，所述无机绝缘层的数量为一层。
  25. 如权利要求24所述的压电传感器，其中，所述无机绝缘层的材料包括SiO 2、Al 2O 3或Si 3N 4。
  26. 如权利要求19-23任一项所述的压电传感器，其中，所述无机绝缘层包括叠层设置的至少两个子层，所述两个子层的材料不同。
  27. 如权利要求26所述的压电传感器，其中，各所述子层的材料包括SiO 2、Al 2O 3或Si 3N 4。
  28. 如权利要求19-23任一项所述的压电传感器，其中，所述走线层的形 状为网格状结构，所述走线层的材料为Ti/Ni/Au、Ti/Au或Ti/Al/Ti。
  29. 如权利要求19-23任一项所述的压电传感器，其中，所述无机绝缘层的厚度为100nm～300nm。
  30. 一种触觉反馈装置，其中，包括如权利要求10-29任一项所述的压电传感器。
PCT/CN2022/084282 2022-03-31 2022-03-31 压电传感器、其驱动方法及触觉反馈装置 WO2023184298A1 (zh)

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