TW202211502A - Method for polarizing piezoelectric film - Google Patents

Abstract

A method for polarizing a piezoelectric film is described. In this method, a piezoelectric film is flat adhered to a surface of a conductive substrate. An insulating barrier is disposed on at least two of edge areas of the piezoelectric film. A polarization process is performed on the piezoelectric film.

Description

The polarization method of piezoelectric film

The present disclosure relates to a fabrication technology of a piezoelectric thin film, and in particular, to a polarization method of the piezoelectric thin film.

The polar directions of the electrical domains in piezoelectric materials often cancel each other out without regularity, which is easy to cause the entire piezoelectric material to have no polarity and cannot exhibit the piezoelectric properties of the material itself. Therefore, it is usually necessary to perform a polarization process on the piezoelectric material, so that the direction of the electric domain of the piezoelectric material can be consistent and the piezoelectric properties can be exhibited.

The non-contact polarization technology uses a high electric field for polarization, and arranges the molecules in the piezoelectric film neatly along the electric field distribution to achieve the effect of making the piezoelectric film exhibit piezoelectric properties. At present, most of the polarization treatments of piezoelectric films use corona discharge technology to provide electron sources. In some polarization equipment using corona discharge technology, electrons will first pass through a negative high-voltage grid (grid) before reaching the surface to be polarized.

However, there is a potential difference between the electrons on the surface of the piezoelectric film and the grounded substrate below, thereby generating an arc. As a result, not only will the polarization of the piezoelectric film be uneven, but the arc will also form arc traces on the piezoelectric film, which will seriously affect the polarization quality and appearance of the piezoelectric film.

Therefore, an object of the present disclosure is to provide a polarization method for a piezoelectric film, which uses an insulating baffle to shield the edge region of the piezoelectric film to prevent electrons from accumulating in the edge region of the piezoelectric film to generate arcs. Thereby, arc traces on the piezoelectric film can be avoided, and the polarization quality and yield of the piezoelectric film can be improved.

Another object of the present disclosure is to provide a polarization method of a piezoelectric film, which can prevent arc discharge during the polarization process, so that the polarization quality and appearance of the piezoelectric film can be considered.

According to the above objective of the present disclosure, a polarization method of a piezoelectric thin film is provided. In this method, the piezoelectric film is flatly attached to the surface of the conductive substrate. An insulating baffle is arranged on at least two of the plurality of edge regions of the piezoelectric film. A polarization process is performed on the piezoelectric film.

According to an embodiment of the present disclosure, the above-mentioned insulating baffle includes a frame-like structure covering all edge regions of the piezoelectric film.

According to an embodiment of the present disclosure, the above-mentioned insulating baffle includes two strip-like structures respectively covering two opposite sides of the edge region of the piezoelectric film.

According to an embodiment of the present disclosure, the above-mentioned polarization process is a roll-to-roll polarization process.

According to an embodiment of the present disclosure, the width of each of the aforementioned edge regions is 3 mm to 50 mm.

According to an embodiment of the present disclosure, a thickness of the above-mentioned insulating baffle is 20 μm to 10 mm.

According to an embodiment of the present disclosure, the above-mentioned insulating baffle protrudes beyond the outer edge of the piezoelectric film.

According to an embodiment of the present disclosure, before performing the polarization process, the above-mentioned method further includes performing a defoaming treatment on the piezoelectric film to remove air bubbles between the piezoelectric film and the surface of the conductive substrate.

According to an embodiment of the present disclosure, the above-mentioned performing the defoaming process includes disposing an auxiliary electrode on the piezoelectric film.

According to an embodiment of the present disclosure, the above-mentioned auxiliary electrode is a conductive plate or a semiconductor plate.

Please refer to FIGS. 1A and 1B , wherein FIG. 1A is a schematic top view illustrating a piezoelectric film disposed on a conductive substrate according to an embodiment of the present disclosure, and FIG. 1B is a section line along A-A of FIG. 1A Schematic diagram of the cross section obtained. In this embodiment, when the piezoelectric film 100 is polarized, the piezoelectric film 100 can be flatly attached to the surface 112 of the conductive substrate 110 first. The piezoelectric film 100 may be an organic piezoelectric film or an inorganic piezoelectric film. The organic piezoelectric film 100 may be a high molecular piezoelectric material, such as, but not limited to, a homopolymer of polyvinylidene fluoride (PVDF). The inorganic piezoelectric thin film can be a piezoelectric ceramic material, such as but not limited to lead zirconate titanate (PZT).

In some examples, the organic piezoelectric film 100 may be fabricated by injection film formation, and then the piezoelectric film 100 may be attached to the surface 112 of the conductive substrate 110 . Before attaching the organic piezoelectric film 100 to the conductive substrate 110 , the piezoelectric film 100 may be stretched first. In other examples, the piezoelectric film 100 can be directly formed on the surface 112 of the conductive substrate 110 by, for example, coating.

The surface 112 of the conductive substrate 110 is preferably a flat surface, so the piezoelectric film 100 can be smoothly attached to the surface 112 of the conductive substrate 110 . In addition, in order to improve the possible deformation of the piezoelectric film 100 during the polarization process, the conductive substrate 110 preferably has a structural strength capable of supporting the piezoelectric film 100 . In some examples, the conductive substrate 110 may be a metal plate, a metal film, a carbon plate, or a metal coil. The metal coil can be applied to the roll-to-roll (RTR) polarization process of the piezoelectric film 100 . During the polarization process, the conductive substrate 110 carries the piezoelectric film 100 to be polarized. For example, for a roll-to-roll or in-line polarization process, the conductive substrate 110 moves with the piezoelectric film 100 . The discontinuous roll of the piezoelectric film 100 in FIG. 1A is suitable for a batch polarization process.

In some examples, the conductive substrate may also include a non-conductive or conductive substrate, and a conductive layer overlying the substrate. The piezoelectric film 100 is flatly attached to the surface of the conductive layer. The non-conductive substrate can be, for example, a plastic film, transparent glass, or a plastic plate. The conductive layer may include, for example, a metal layer, a conductive oxide layer, or a carbon nanopowder layer.

When the piezoelectric film 100 is attached to the surface 112 of the conductive substrate 110 , air bubbles may be generated between the attached surface 102 of the piezoelectric film 100 and the surface 112 of the conductive substrate 110 . Therefore, the defoaming treatment can be selectively performed according to the bonding condition, so as to remove the air bubbles between the bonding surface 102 of the piezoelectric film 100 and the surface 112 of the conductive substrate 110 . The defoaming treatment can be performed by, for example, a scraping method, a vacuum method, a pressing method, and/or an electrostatic adsorption method.

The piezoelectric film 100 has a plurality of edge regions. For example, as shown in FIG. 1A , the piezoelectric film 100 is a quadrilateral film with four edge regions 104a-104d. Please refer to FIG. 2A and FIG. 2B , wherein FIG. 2A is a schematic top view of an insulating baffle disposed on a piezoelectric film according to an embodiment of the present disclosure, and FIG. 2B is a schematic view along the section line A-A of FIG. 2A Schematic diagram of the cross section obtained. Next, the insulating baffles 120 are disposed on the edge regions 104 a to 104 d of the piezoelectric film 100 to cover all the edge regions 104 a to 104 d of the piezoelectric film 100 . The material of the insulating baffle 120 can be a material with high insulating coefficient, such as ceramics, plastics such as polytetrafluoroethylene (PTFE) and polyimide (PI), mica, and glass.

The shape and structure of the insulating barrier 120 depend on the shape of the piezoelectric film 100 . In the example of FIG. 2A and FIG. 2B , the piezoelectric film 100 is quadrilateral and has four edge regions 104a-104d, so the insulating baffle 120 includes a frame-like structure formed by four frames 122a-122d. When the piezoelectric thin film is circular, oval, or polygonal, the insulating baffle 120 may correspond to a circular frame, an oval frame, or a polygonal frame.

The frames 122 a ˜ 122 d cover the entire edge regions 104 a ˜ 104 d of the piezoelectric film 100 , respectively. The frames 122a-122d need to cover the outermost edges of the edge regions 104a-104d, respectively. In some examples, the outer edges of the borders 122a-122d may be aligned with the outer edges of the edge regions 104a-104d, respectively, as shown in FIG. 2B. The frames 122a to 122d can also protrude from the outer edges of the edge regions 104a to 104d of the piezoelectric film 100, respectively, as shown in FIG. 4 . Therefore, please refer to FIG. 1A and FIG. 2A simultaneously, the width 124 of each frame 122a-122d may be equal to or greater than the width 106 of the corresponding edge regions 104a-104d. The suitable width 106 of the edge regions 104a-104d depends on the voltage of the polarization process, and the thickness 126 of the frames 122a-122d depends on the material type of the insulating baffle 120 and the voltage of the polarization process. In some illustrative examples, the width 106 of each edge region 104a-104d may be about 3 mm to about 50 mm. In addition, the thickness 126 of each of the frames 122a-122d may be, for example, about 20 μm to about 10 mm.

Please refer to FIG. 3 , which is a schematic diagram of a device for a polarization process of a piezoelectric film according to an embodiment of the present disclosure. After the insulating baffle 120 is covered on the edge regions 104a-104d of the piezoelectric film 100, the piezoelectric film 100 can be subjected to a polarization process, so that the piezoelectric film 100 exhibits piezoelectric properties. In some examples, the piezoelectric film 100 may be polarized using plasma. During the polarization process, the polarization electrode 130 can be disposed above the piezoelectric film 100 , the first electrode 142 of the power supply 140 is electrically connected to the polarization electrode 130 , and the second electrode 140 of the power supply 140 is electrically connected. The pole 144 is grounded to the conductive substrate 110 . The first pole 142 and the second pole 144 of the power supply 140 have different potentials.

After the power supply 140 supplies power to the polarizing electrode 130 , the polarizing electrode 130 can generate plasma and spray toward the piezoelectric film 100 , so as to use the electrons in the plasma to polarize the piezoelectric film 100 . In some examples, a grid (not shown) can be disposed between the polarizing electrode 130 and the piezoelectric film 100 . The voltage of the grid can be the same as or similar to the voltage of the polarized electrode 130 , or less than the voltage of the polarized electrode 130 .

During the polarization process, since the insulating baffle 120 covers all the edge regions 104a-104d of the piezoelectric film 100, electrons in the plasma can be prevented from accumulating on the edge regions 104a-104d. Therefore, arcs can be prevented from being generated between the edge regions 104 a to 104 d of the piezoelectric film 100 and the grounded conductive substrate 110 , and arc traces can be prevented from being generated on the piezoelectric film 100 . In this way, not only a piezoelectric film with good appearance can be obtained, but also the polarization quality and yield of the piezoelectric film 100 can be improved. In addition, the pressing force of the insulating baffle 120 on the edge regions 104a-104d of the piezoelectric film 100 can maintain the flatness of the piezoelectric film 100 during the polarization process, which is beneficial to the application of the piezoelectric film 100 after polarization.

Please refer to FIG. 5A and FIG. 5B , which are a schematic top view of an insulating baffle provided on a piezoelectric film according to an embodiment of the present disclosure, and a schematic cross-sectional view taken along the section line A-A in FIG. 5A , respectively. . The piezoelectric film 200 of this embodiment is a continuous roll, which is suitable for a roll-to-roll polarization process. The piezoelectric film 200 may be an organic piezoelectric film or an inorganic piezoelectric film. The piezoelectric film 200 may be, for example, but not limited to, a homopolymer of polyvinylidene fluoride and lead zirconate titanate.

The piezoelectric film 200 is flatly attached to the surface 212 of the conductive substrate 210 . The surface 212 of the conductive substrate 210 is preferably a flat surface, so as to maintain the flatness of the piezoelectric film 200 . The conductive substrate 210 has sufficient structural strength to effectively support the piezoelectric film 200 during the polarization process. The conductive substrate 210 may be a carbon coil or a metal coil. In some examples, the conductive substrate may also include a non-conductive or conductive substrate, and a conductive layer covering the substrate, wherein the piezoelectric film 200 is flat on the surface of the conductive layer. The substrate can be, for example, a plastic film, transparent glass, or a plastic plate. The conductive layer may include, for example, a metal layer, a conductive oxide layer, or a carbon nanopowder layer.

Since the piezoelectric film 200 is a continuous roll, during the polarization process, the insulating baffle 220 only needs to cover the two edge regions 202 a and 202 b of the piezoelectric film 200 . The two edge regions 202 a and 202 b are respectively located on two opposite sides of the piezoelectric film 200 and extend along the length direction of the piezoelectric film 200 . The insulating baffle 220 may include two strip-shaped structures 222 a and 222 b to cover the entire edge regions 202 a and 202 b of the piezoelectric film 200 , respectively. The material of the insulating baffle 220 can be a material with high insulating coefficient, such as ceramics, plastics such as PTFE and polyimide, mica, and glass.

The strip structures 222a and 222b need to cover the outermost edges of the edge regions 202a and 202b, respectively. Similarly, the outer edges of the strip structures 222a and 222b can be aligned with the outer edges of the edge regions 202a and 202b, respectively, as shown in FIG. 5B; or, the strip structures 222a and 222b can protrude from the edge of the piezoelectric film 200, respectively outside the outer edges of regions 202a and 202b. The width 224 of each strip structure 222a may be equal to or greater than the width 204 of the corresponding edge regions 202a and 202b. In some demonstrative examples, the width 204 of each edge region 202a and 202b may be about 3 mm to about 50 mm. In addition, the thickness 226 of each of the strip structures 222a and 222b may be, for example, about 20 μm to about 10 mm.

Please refer to FIG. 6A and FIG. 6B , which are schematic top views of an insulating baffle and an auxiliary electrode disposed on a piezoelectric film according to an embodiment of the present disclosure, and obtained along the section line A-A in FIG. 6A , respectively. cross-sectional schematic diagram. Before polarization, during polarization, and after polarization, air bubbles may exist between the bonding surface 102 of the piezoelectric film 100 and the surface 112 of the conductive substrate 110 . Therefore, in some examples, the auxiliary electrode 150 may be additionally disposed, and the auxiliary electrode 150 may be pressed against the piezoelectric film 100 . In some exemplary examples, the insulating baffle 120 is disposed outside the auxiliary electrode 150 , that is, the frames 122 a - 122 d of the insulating baffle 120 surround the outside of the auxiliary electrode 150 . However, the size of the auxiliary electrode 150 is not limited to the hollow size of the frame-shaped insulating baffle 120 , that is, the size of the auxiliary electrode 150 may be larger than the hollow size of the insulating baffle 120 .

The auxiliary electrode 150 can remove the air bubbles between the bonding surface 102 of the piezoelectric film 100 and the surface 112 of the conductive substrate 110 by pressing before, during and after the polarization of the piezoelectric film 100 . The flatness of the piezoelectric film 100 is maintained. The auxiliary electrode 150 may be, for example, a conductive plate or a semiconductor plate.

As can be seen from the above-mentioned embodiments, one of the advantages of the present disclosure is that the polarization method of the piezoelectric film of the present disclosure uses an insulating baffle to shield the edge region of the piezoelectric film to prevent electrons from accumulating in the edge region of the piezoelectric film and causing arcing . Thereby, arc traces on the piezoelectric film can be avoided, and the polarization quality and yield of the piezoelectric film can be improved.

As can be seen from the above-mentioned embodiments, another advantage of the present disclosure is that the polarization method of the piezoelectric film of the present disclosure can prevent arc discharge during the polarization process, so that both the polarization quality and the appearance of the piezoelectric film can be considered.

Although the present disclosure has been disclosed above with examples, it is not intended to limit the present disclosure. Anyone with ordinary knowledge in this technical field can make various changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the appended patent application.

100: Piezo Film 102: Fitting the surface 104a: Marginal Zone 104b: Marginal Zone 104c: Marginal Zone 104d: Edge Zone 106: width 110: Conductive substrate 112: Surface 120: Insulation baffle 122a: Border 122b: Border 122c: Border 122d: border 124:width 126: Thickness 130: polarized electrodes 140: Power Supply 142: First Pole 144: second pole 150: auxiliary electrode 200: Piezo Film 202a: Marginal Zone 202b: Marginal Zone 204:width 210: Conductive substrates 212: Surface 220: Insulation baffle 222a: stripe structure 222b: stripe structure 224:width 226: Thickness

In order to make the above and other objects, features, advantages and embodiments of the present disclosure more clearly understood, the accompanying drawings are described as follows: 1A is a schematic top view illustrating a piezoelectric film disposed on a conductive substrate according to an embodiment of the present disclosure; [FIG. 1B] is a schematic cross-sectional view taken along the section line A-A of FIG. 1A; [ FIG. 2A ] is a schematic top view illustrating an insulating baffle provided on a piezoelectric film according to an embodiment of the present disclosure; [FIG. 2B] is a schematic cross-sectional view obtained along the A-A section line of FIG. 2A; [ FIG. 3 ] is a schematic diagram of a device for a polarization process of a piezoelectric thin film according to an embodiment of the present disclosure; [ FIG. 4 ] is a schematic cross-sectional view illustrating an insulating baffle provided on a piezoelectric film according to an embodiment of the present disclosure; [ FIG. 5A ] is a schematic top view illustrating an insulating baffle provided on a piezoelectric film according to an embodiment of the present disclosure; [FIG. 5B] is a schematic cross-sectional view obtained along the A-A section line of FIG. 5A; [ FIG. 6A ] is a schematic top view illustrating an insulating baffle and an auxiliary electrode disposed on a piezoelectric film according to an embodiment of the present disclosure; and [ FIG. 6B ] is a schematic cross-sectional view taken along the section line A-A of FIG. 6A .

Domestic storage information (please note in the order of storage institution, date and number) without Foreign deposit information (please note in the order of deposit country, institution, date and number) without

100: Piezo Film

102: Fitting the surface

104b: Marginal Zone

104d: Edge Zone

110: Conductive substrate

112: Surface

120: Insulation baffle

122a: Border

122b: Border

122d: border

124:width

126: Thickness

Claims (10)

A polarization method of a piezoelectric film, comprising: A piezoelectric film is flatly attached to a surface of a conductive substrate; disposing an insulating baffle on at least two of the plurality of edge regions of the piezoelectric film; and A polarization process is performed on the piezoelectric film. The method of claim 1, wherein the insulating baffle comprises a frame-like structure covering all the edge regions of the piezoelectric film. The method as claimed in claim 1, wherein the insulating baffle comprises two strip-like structures respectively covering opposite two of the edge regions of the piezoelectric film. The method of claim 3, wherein the polarization process is a roll-to-roll polarization process. The method of claim 1, wherein a width of each of the edge regions is 3 mm to 50 mm. The method of claim 1, wherein a thickness of the insulating baffle is 20 μm to 10 mm. The method of claim 1, wherein the insulating baffle protrudes beyond an outer edge of the piezoelectric film. The method as claimed in claim 1, wherein before performing the polarization process, the method further comprises performing a defoaming treatment on the piezoelectric film to remove the bubbles between the piezoelectric film and the surface of the conductive substrate bubble. The method of claim 8, wherein performing the defoaming process comprises disposing an auxiliary electrode on the piezoelectric film. The method of claim 9, wherein the auxiliary electrode is a conductive plate or a semiconductor plate.

Images