TWI585375B - Ultrasonic sensor and manufacturing method thereof - Google Patents

Description

Ultrasonic sensor and manufacturing method thereof

The invention relates to a method for manufacturing an ultrasonic sensor and an ultrasonic sensor.

Material wave sensing elements using piezoelectric films and the like as piezoelectric materials have been widely used in various fields such as industry, national defense, fire protection, and electronics. A typical matter wave sensing element is an ultrasonic sensor. Among them, ultrasonic sensors are widely used in harsh environments such as public places because of their operability, environmental temperature and humidity, long life and high resolution. The ultrasonic sensor generally includes a transparent electrode layer for emitting and receiving a voltage, and a piezoelectric material layer for generating an ultrasonic wave, and the first electrode and the piezoelectric material layer of the transparent electrode layer pass through an edge region of the ultrasonic sensor. A conductive film is connected, and when the conductive film is coated, the edge of the film is not sharp due to the large surface tension of the piezoelectric material, resulting in a decrease in touch precision.

In view of the above, it is necessary to provide an ultrasonic sensor and a method of manufacturing the same.

An ultrasonic sensor includes: a substrate; a first electrode and a first piezoelectric material layer are stacked on one side of the substrate; and a second electrode and a second piezoelectric material layer are stacked on the other side of the substrate; The first piezoelectric material layer is provided with a notch; the conductive film is coated with the notch for connecting the first electrode and the first piezoelectric material layer.

A method of manufacturing an ultrasonic sensor, comprising: Providing a substrate, a first electrode and a second electrode are formed on both sides of the substrate; a first piezoelectric material layer is coated on the first electrode, and a second piezoelectric material layer is coated on the second electrode; A gap is defined on a layer of piezoelectric material; and a conductive film is coated on the gap to connect the first electrode and the first layer of piezoelectric material.

Compared with the prior art, the ultrasonic sensor and the manufacturing method of the present invention provide a notch on the second piezoelectric material layer, and connect the first electrode and the first piezoelectric material layer through the conductive film at the notch, thereby solving The phenomenon that the conductive film is coated with a corner due to a large surface of the piezoelectric material increases the sensing accuracy of the ultrasonic sensor.

100‧‧‧Ultrasonic Sensor

10‧‧‧First piezoelectric material layer

11‧‧‧First electrode

12‧‧‧First colloid layer

13‧‧‧Substrate

14‧‧‧Second colloid layer

15‧‧‧second electrode

16‧‧‧Second piezoelectric material layer

17‧‧‧Electrical film

102‧‧‧ gap

S201~S207‧‧‧Steps

1 is a top plan view of an ultrasonic sensor of the present invention.

2 is a perspective view showing the side view structure of the ultrasonic sensor shown in FIG. 1.

3 is a cross-sectional view of the ultrasonic sensor of FIG. 1 taken along line III-III.

4 to 7 are structural diagrams showing the manufacturing steps of the ultrasonic sensor of the present invention.

Figure 8 is a flow chart of a method of manufacturing the ultrasonic sensor of the present invention.

Please refer to FIG. 1 , FIG. 2 and FIG. 3 . FIG. 1 is a top view of the ultrasonic sensor 100 of the present invention, and FIG. 2 is a perspective view showing the structure of one side of the ultrasonic sensor 100 of FIG. 1 . 3 is a schematic cross-sectional view of the ultrasonic sensor 100 taken along line III-III. The ultrasonic sensor 100 includes a first piezoelectric material layer 10, a first electrode 11, a first colloid layer 12, a substrate 13, a second colloid layer 14, a second electrode 15, and a second piezoelectric material layer which are sequentially stacked. 16 and a conductive film 17 for connecting the first electrode 11 and the first piezoelectric material layer 10. The first electrode 11 is bonded to one side of the substrate 13 through the first colloid layer 12 . The second electrode 15 is bonded to the opposite side of the substrate 13 through the second colloid layer 14. In this embodiment, the first colloid layer 12 and the second colloid layer 14 are photocurable adhesives.

The substrate 13 is a transparent substrate such as a glass substrate, a quartz substrate, a sapphire substrate or a flexible transparent substrate. In the present embodiment, the substrate 13 is a glass substrate.

In a modified embodiment, the first electrode 11 and the second electrode 15 may be directly formed on the substrate 13. The material of the first electrode 11 and the second electrode 15 is a single layer transparent conductive material or a multilayer composite transparent conductive material. The single-layer transparent conductive material includes, but is not limited to, Indium Tin Oxide (ITO), zinc oxide (ZnO), polyethylene dioxythiophene (PEDOT), carbon nanotube (CNT), silver nanowire ( AgNW) and graphene. The multilayer composite transparent conductive material includes, but is not limited to, a three-layer composite structure conductive material composed of indium tin oxide, silver, indium tin oxide which are sequentially laminated.

The first piezoelectric material layer 10 is coated on the first electrode 11. The material of the first piezoelectric material layer 10 is Polyvinylidene Fluoride (PVDF). In a modified embodiment, the first piezoelectric material layer 10 is made of aluminum nitride, lead zirconium titanate (PZT), lithium niobate (LiTaO ₃ ), cerium oxide (SiO ₂ ), and oxidation. Zinc (ZnO) and the like. The first piezoelectric material layer 10 is a single layer structure or a multilayer composite material structure. The first piezoelectric material layer 10 defines a conductive portion on one edge region, and the conductive portion is disposed as a notch 102. The cross-sectional shape of the notch 102 is, but not limited to, a trapezoid. In the present embodiment, the thickness of the first piezoelectric material layer 10 is greater than 5 μm.

The conductive film 17 is used to connect the first piezoelectric material layer 10 and the first electrode 11 , and the conductive film 17 is disposed at the gap 102 . The material of the conductive film 17 is a silver paste, and the diameter of the conductive particles in the silver paste is larger than 0.01 μm and smaller than 10 μm. In the present embodiment, the thickness of the conductive film 17 is less than 10 μm, and the cohesive force of the material of the conductive film 17 is greater than the surface tension of the piezoelectric material.

The second piezoelectric material layer 16 is coated on the second electrode 15. The material of the second piezoelectric material layer 16 is Polyvinylidene Fluoride (PVDF). In a modified embodiment, the second piezoelectric material layer 16 is made of aluminum nitride, lead zirconium titanate (PZT), lithium niobate (LiTaO ₃ ), cerium oxide (SiO ₂ ), and oxidation. Zinc (ZnO) and the like. The second piezoelectric material layer 16 is a single layer structure or a multilayer composite material structure.

In the present embodiment, the second electrode 15 is an output voltage to the transmitting electrode of the second piezoelectric material layer 16, and the first electrode 11 is a receiving electrode that receives the voltage output from the first piezoelectric material layer 10. When the ultrasonic sensor 100 is in operation, the second electrode 15 applies a voltage to the second piezoelectric material layer 16, and the second piezoelectric material layer 16 generates vibrations under the action of a voltage to emit ultrasonic waves from the surface. When a finger or a stylus or the like contacts the ultrasonic sensor 100, the ultrasonic wave is reflected by the finger to the first The piezoelectric material layer 10 converts the ultrasonic wave into an electrical signal, and transmits an electrical signal to the wafer through the conductive film 17 to determine a touch position, a size, a pressure parameter, and the like.

The ultrasonic sensor 100 further includes an insulating layer covering the piezoelectric material layer to protect the piezoelectric material layer. The material of the insulating layer may be boron nitride, insulating diamond-like carbon or a combination thereof.

Please refer to FIG. 4 to FIG. 8 together. FIG. 4 to FIG. 7 are schematic structural diagrams of manufacturing steps of the ultrasonic sensor of the present invention. Figure 8 is a flow chart of a method of manufacturing the ultrasonic sensor of the present invention.

Step S201, referring to FIG. 4, a substrate 13 is provided, and the first electrode 11 and the second electrode 15 are formed on both sides of the substrate 13. The first electrode 11 is bonded to one side of the substrate 13 through the first colloid layer 12 . The second electrode 15 is bonded to the opposite side of the substrate 13 through the second colloid layer 14. The substrate 13 is a transparent substrate such as a glass substrate, a quartz substrate, a sapphire substrate or a flexible transparent substrate. In the present embodiment, the substrate 13 is a glass substrate. The material of the first electrode 11 and the second electrode 15 is a single layer transparent conductive material or a multilayer composite transparent conductive material. The single-layer transparent conductive material includes, but is not limited to, Indium Tin Oxide (ITO), zinc oxide (ZnO), polyethylene dioxythiophene (PEDOT), carbon nanotube (CNT), silver nanowire ( AgNW) and graphene. The multilayer composite transparent conductive material includes, but is not limited to, a three-layer composite structure conductive material composed of indium tin oxide, silver, indium tin oxide which are sequentially laminated. In the present embodiment, a transparent conductive material may be deposited by a deposition method such as a sputtering method, a vacuum evaporation method, a pulsed laser deposition method, an ion plating method, an organometallic vapor phase epitaxy method, or a plasma CVD method, and the transparent conductive layer may be patterned. The material forms the first electrode 11 and the second electrode 15.

Step S203, referring to FIG. 5, the first piezoelectric material layer 10 is coated on the first electrode 11, and the second piezoelectric material layer 16 is coated on the second electrode 15. The material of the first piezoelectric material layer 10 and the second piezoelectric material layer 16 is Polyvinylidene Fluoride (PVDF). In a modified embodiment, the first piezoelectric material layer 10 and the second piezoelectric material layer 16 are made of aluminum nitride, lead zirconium titanate (PZT), lithium niobate (LiTaO ₃ ), Cerium oxide (SiO ₂ ), zinc oxide (ZnO), and the like. The first piezoelectric material layer 10 and the second piezoelectric material layer 16 are a single layer structure or a multilayer composite material structure. In the present embodiment, the thickness of the first piezoelectric material layer 10 is greater than 5 μm. Specifically, a deposition method such as a sputtering method, a vacuum evaporation method, a pulsed laser deposition method, an ion plating method, an organometallic vapor phase epitaxy method, or a plasma CVD method can be used to form a second electrode 15 and a first electrode 11 . A piezoelectric material is patterned and the piezoelectric material is patterned to form a first piezoelectric material layer 10 and a second piezoelectric material layer 16.

Step S205, referring to FIG. 6, a notch 102 is defined on the first piezoelectric material layer 10. The cross-sectional shape of the notch 102 is, but not limited to, a trapezoid.

Step S207, referring to FIG. 7, a conductive film 17 is applied to the notch 102 to connect the first electrode 11 and the first piezoelectric material layer 10. The material of the conductive film 17 is a silver paste, and the diameter of the conductive particles in the silver paste is larger than 0.01 μm and smaller than 10 μm. In the present embodiment, the thickness of the conductive film 17 is less than 10 μm, and the cohesive force of the conductive particles in the material of the conductive film 17 is greater than the surface tension of the piezoelectric material.

The ultrasonic sensor 100 and the manufacturing method of the present invention are provided with a notch 102 in the first piezoelectric material layer 10 to connect the transparent electrode through the conductive film 17, thereby reducing the surface tension at the notch of the first piezoelectric material layer 10 to solve The phenomenon that the conductive film is coated with a corner due to a large surface of the piezoelectric material increases the sensing accuracy of the ultrasonic sensor.

While the invention has been described above in terms of a preferred embodiment thereof, it is not intended to limit the invention, and various modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Changes are intended to be included within the scope of the claimed invention.

100‧‧‧Ultrasonic Sensor

10‧‧‧First piezoelectric material layer

11‧‧‧First electrode

12‧‧‧First colloid layer

13‧‧‧Substrate

14‧‧‧Second colloid layer

15‧‧‧second electrode

16‧‧‧Second piezoelectric material layer

17‧‧‧Electrical film

102‧‧‧ gap

Claims (9)

An ultrasonic sensor includes: a substrate; a first electrode and a first piezoelectric material layer are stacked on one side of the substrate; and a second electrode and a second piezoelectric material layer are stacked on the other side of the substrate; The second electrode is an output voltage to the transmitting electrode of the second piezoelectric material layer, the first electrode is a receiving electrode that receives the voltage outputted by the first piezoelectric material layer; and the first piezoelectric material layer is provided with a notch; The conductive film coats the gap for connecting the first electrode and the first piezoelectric material layer. The ultrasonic sensor according to claim 1, wherein the conductive film is made of silver paste. The ultrasonic sensor of claim 2, wherein the conductive particles in the silver paste have a diameter greater than 0.01 μm and less than 10 μm. The ultrasonic sensor according to claim 1, wherein the conductive film has a thickness of less than 10 μm. The ultrasonic sensor according to claim 1, wherein the cohesive force of the conductive particles in the conductive film is greater than the surface tension of the piezoelectric material layer. The ultrasonic sensor of claim 1, wherein the first electrode and the second electrode are made of a single layer of transparent conductive material. The ultrasonic sensor according to claim 6, wherein the single-layer transparent conductive material comprises indium tin oxide, zinc oxide, polyethylene dioxythiophene, carbon nanotubes, silver nanowires, and graphene. The ultrasonic sensor according to claim 1, wherein the first and second piezoelectric material layers are made of polydifluoroethylene. A method for manufacturing an ultrasonic sensor, comprising: providing a substrate, forming a first electrode and a second electrode on both sides of the substrate; applying a first piezoelectric material layer on the first electrode, the second electrode Coating a second piezoelectric material layer; defining a notch on the first piezoelectric material layer; and coating a conductive film on the notch to connect the first electrode and the first piezoelectric material layer.