TWI689114B - Piezoelectric ceramic apparatus and forming method thereof - Google Patents

Abstract

A piezoelectric ceramic apparatus includes an upper electrode layer, a lower electrode layer, a piezoelectric ceramic material layer, a conformal coating layer, and a pressure sensitive adhesive layer. The piezoelectric ceramic material layer is disposed between the upper electrode layer and the lower electrode layer. The conformal coating layer is disposed at the left side and the right side of the piezoelectric ceramic material layer. The pressure sensitive adhesive layer covers the upper electrode layer and the conformal coating layer.

Description

Piezoelectric ceramic device and its forming method

The disclosed embodiments relate to a piezoelectric ceramic device, and particularly to a piezoelectric ceramic device and a method of forming the same.

Piezoelectric materials are materials that have a piezoelectric effect that changes the polarization of an electrode by receiving stress from the outside, and a reverse piezoelectric effect that produces a skew by applying an electric field. Piezoelectric ceramic materials are widely used in piezoelectric vibrators , Piezoelectric filters, piezoelectric actuators, piezoelectric transformers or piezoelectric buzzers and other piezoelectric ceramic devices.

The purpose of the present disclosure is to propose a piezoelectric ceramic device including an upper electrode layer, a lower electrode layer, a piezoelectric ceramic material layer, a conformal coating (CC) layer and a pressure sensitive adhesive (Pressure Sensitive Adhesive PSA) layer. The piezoelectric ceramic material layer is interposed between the upper electrode layer and the lower electrode layer. Three anti-adhesive layers are provided on the left and right sides of the piezoelectric ceramic material layer. The pressure sensitive adhesive layer covers the upper electrode layer and the three anti-adhesive layer.

In some embodiments, the piezoelectric ceramic device further includes a flexible printed circuit board (FPC), and the lower electrode layer is bonded to the flexible printed circuit board through conductive adhesive (Conductive Adhesive).

In some embodiments, the three anti-adhesive layers are disposed on the flexible printed circuit board, and the pressure-sensitive adhesive layer covers the flexible printed circuit board.

In some embodiments, the Young's Modulus of the three rubber-proof layers is greater than 1 GPa.

In some embodiments, the shape of the three adhesive layers in the cross section is triangular, so that the turning angles of the pressure-sensitive adhesive layer are all greater than 100 degrees.

The purpose of the present disclosure is to provide another method for forming a piezoelectric ceramic device, which includes: providing a piezoelectric ceramic material layer sandwiched between an upper electrode layer and a lower electrode layer; performing a dispense process to make the three anti-adhesives The layers are arranged on the left and right sides of the piezoelectric ceramic material layer; and an encapsulation (Encapsulating) process is performed to make the pressure-sensitive adhesive layer cover the upper electrode layer and the three anti-adhesive layer.

In some embodiments, the method for forming the piezoelectric ceramic device further includes: before performing the dispensing process, a spray process is used to distribute the Anisotropic Conductive Adhesive (ACA) in the flexible printing A circuit board; and a bonding process to bond the lower electrode layer to the flexible printed circuit board through the anisotropic conductive adhesive.

In some embodiments, the three anti-adhesive layers are disposed on the flexible printed circuit board, and the pressure-sensitive adhesive layer covers the flexible printed circuit board.

In some embodiments, the Young's modulus of the above three rubber-proof layers is greater than 1 GPa.

In some embodiments, the cross-sectional shape of the three adhesive layers is triangular, so that the turning angles of the pressure-sensitive adhesive layer are all greater than 100 degrees.

In order to make the above-mentioned features and advantages of the present disclosure more comprehensible, the embodiments are specifically described below and described in detail in conjunction with the accompanying drawings.

The embodiments of the present invention are discussed in detail below. However, it can be understood that the embodiments provide many applicable concepts that can be implemented in a variety of specific contents. The discussed and disclosed embodiments are for illustration only and are not intended to limit the scope of the present invention.

FIG. 1 is a cross-sectional view of a piezoelectric ceramic device 100 according to the first embodiment of the present disclosure. The piezoelectric ceramic device 100 includes an upper electrode layer 110, a lower electrode layer 120, a piezoelectric ceramic material layer 130, and a flexible printed circuit (FPC) 140. The piezoelectric ceramic material layer 130 is interposed between the upper electrode layer 110 and the lower electrode layer 120. The flexible printed circuit board 140 has a contact pad 142 and a contact pad 144 respectively connected to the upper electrode layer 110 and the lower electrode layer 120 through a conductive adhesive (Conductive Adhesive) 150.

The forming method of the piezoelectric ceramic device 100 includes: providing a piezoelectric ceramic material layer 130 sandwiched between the upper electrode layer 110 and the lower electrode layer 120; through a spraying process to make the liquid conductive adhesive 150 evenly distributed in the soft On the printed circuit board 140; and performing a bonding process so that the upper electrode layer 110 and the lower electrode layer 120 are respectively bonded to the contact pads 142 and the contact pads 144 of the flexible printed circuit board 140 through the cured conductive adhesive 150. In the above-mentioned forming method, the conductive adhesive 150 may be anisotropic conductive adhesive (Anisotropic Conductive Adhesive, ACA), but the disclosure is not limited thereto. Among them, the above-mentioned joining process includes pressure pressing and thermal curing (thermal curing), the pressure parameter of pressure pressing is 0.23 MPa (MPa), the temperature parameter of heat curing is 120 degrees C, the pressure pressing and The time parameter of heat hardening is 170 seconds, but the disclosure is not limited to this.

When the piezoelectric ceramic material layer 130 is subjected to pressure, a voltage difference will appear on the upper and lower sides. At this time, the flexible printed circuit board 140 obtains the upper electrode layer 110 and the lower electrode layer 120 through the contact pad 142 and the contact pad 144, respectively. The voltage value, so that the voltage difference can be used to obtain the mechanical energy received by the piezoelectric ceramic material layer 130 through an appropriate conversion operation, such as vibration force or the lower pressure channel, etc. The conversion of the electrode voltage difference into mechanical energy is known to those skilled in the art and will not be described in this article.

Since the upper electrode layer 110, the lower electrode layer 120, and/or the conductive adhesive 150 of the piezoelectric ceramic device 100 still have some exposed parts, in practice, the piezoelectric ceramic device 100 is usually sealed ( Encapsulating) to better protect the piezoelectric ceramic device 100. 2A to 2B are schematic diagrams of the sealing process of the piezoelectric ceramic device 100 according to the first embodiment of the present disclosure. Referring to FIG. 2A, the sealing machine includes a vacuum pump 210, an upper working table 220, a soft rubber (sticky rubber) 230, a lower working table 240, and a heating system 250. The piezoelectric ceramic device 100 is disposed on the lower table 240, and the vacuum pump 210 is used to make the vacuum in the chamber of the sealing machine less than 0.2 torr. An encapsulation film (Encapsulation Film) 260 is provided on the lower surface of the soft rubber 230. Please refer to FIG. 2B, which is a schematic diagram of lamination. Lamination is performed with a pressure parameter of 0.5 MPa and a time parameter of 2 minutes.

FIG. 3 is a cross-sectional view of the piezoelectric ceramic device 300 after sealing according to the first embodiment of the present disclosure. The encapsulated piezoelectric ceramic device 300 further includes a pressure sensitive adhesive (Pressure Sensitive Adhesive PSA) layer 160. The pressure sensitive adhesive layer 160 covers the upper electrode layer 110 and the flexible printed circuit board 140. Please refer to FIGS. 2B and 3 together. During sealing, due to the step height of each element in the piezoelectric ceramic device 100, the soft rubber 230 and the left and right sides of the piezoelectric ceramic device 100 cannot be completely bonded Therefore, the presence of bubbles 310 in the piezoelectric ceramic device 300 after sealing is generated on the left and right sides of the piezoelectric ceramic material layer 130. The bubble 310 has an adverse effect on the piezoelectric ceramic device 300 after being encapsulated. For example, the vibration energy of the piezoelectric ceramic device 300 after being encapsulated may be reduced due to the bubble 310. Accordingly, the present disclosure proposes a second embodiment to improve the above-mentioned defects.

FIG. 4 is a cross-sectional view of a piezoelectric ceramic device 400 according to the second embodiment of the present disclosure. The piezoelectric ceramic device 400 includes an upper electrode layer 110, a lower electrode layer 120, a piezoelectric ceramic material layer 130, a flexible printed circuit board 140, and a conformal coating (CC) layer 170. The piezoelectric ceramic material layer 130 is interposed between the upper electrode layer 110 and the lower electrode layer 120. The flexible printed circuit board 140 has contact pads 142 and contact pads 144 respectively joined to the upper electrode layer 110 and the lower electrode layer 120 through the conductive adhesive 150. The three anti-adhesive layers 170 are disposed on the left and right sides of the piezoelectric ceramic material layer 130, and the three anti-adhesive layers 170 are disposed on the flexible printed circuit board 140.

The forming method of the piezoelectric ceramic device 400 includes: providing the piezoelectric ceramic material layer 130 sandwiched between the upper electrode layer 110 and the lower electrode layer 120; through a spraying process to make the liquid conductive adhesive 150 evenly distributed in the soft On the printed circuit board 140; a bonding process is performed so that the upper electrode layer 110 and the lower electrode layer 120 are respectively bonded to the contact pads 142 and the contact pads 144 of the flexible printed circuit board 140 through the cured conductive adhesive 150; In the process of dispense, the three anti-adhesive layers 170 are disposed on the left and right sides of the piezoelectric ceramic material layer 130, and the three anti-adhesive layers 170 are disposed on the flexible printed circuit board 140.

In the second embodiment of the present disclosure, the Young's Modulus of the three anti-adhesive layer 170 is greater than 1 GPa, but the present disclosure is not limited thereto. As shown in FIG. 4, in the second embodiment of the present disclosure, the shape of the three adhesive layers 170 in the cross-sectional direction is a triangle.

FIG. 5 is a schematic view of a sealant of a piezoelectric ceramic device 400 according to the second embodiment of the present disclosure. FIG. 5 is a schematic diagram of lamination. FIG. 5 is similar to FIGS. 2A and 2B, so the similarities will not be repeated. FIG. 6 is a cross-sectional view of the piezoelectric ceramic device 600 after sealing according to the second embodiment of the present disclosure. The encapsulated piezoelectric ceramic device 600 further includes a pressure-sensitive adhesive layer 160 that covers the upper electrode layer 110, the three-adhesive layer 170 and the flexible printed circuit board 140. Please refer to FIG. 5 and FIG. 6 together, when the sealing is performed, since the piezoelectric ceramic device 400 has been provided with a three-adhesive layer 170 on the left and right sides of the piezoelectric ceramic material layer 130 through the dispensing process, and the three-adhesive layer The shape of 170 in the cross-sectional direction is a triangle, and the soft rubber 230 and the left and right sides of the piezoelectric ceramic device 400 can be completely adhered to, so there is no air bubble in the piezoelectric ceramic device 600 after sealing, which can be improved The piezoelectric ceramic device 300 after being encapsulated is adversely affected by the presence of bubbles 310.

It is worth mentioning that, in the second embodiment of the present disclosure, the triangular shape of the three adhesive layers 170 of the piezoelectric ceramic device 400 in the cross-sectional direction should not be too steep, so that when sealing, The soft rubber 230 can be completely attached to the left and right sides of the piezoelectric ceramic device 400. Specifically, the shape of the three-proof adhesive layer 170 in the cross-section is not too steep, so that each turning angle of the pressure-sensitive adhesive layer 160 of the piezoelectric ceramic device 600 after being encapsulated is greater than 100 degrees.

In summary, the present disclosure proposes a piezoelectric ceramic device and a method for forming the same. By setting three anti-adhesive layers on the left and right sides of the piezoelectric ceramic material layer through a dispensing process, the piezoelectric ceramic device after sealing No bubbles will be generated, and the vibration energy of the piezoelectric ceramic device after sealing will not be reduced due to the generation of bubbles.

The above outlines the features of several embodiments, so those skilled in the art can better understand the aspect of the present disclosure. Those skilled in the art should understand that they can easily use the present disclosure as a basis to design or modify other processes and structures, thereby achieving the same goals and/or achieving the same advantages as the embodiments described herein . Those skilled in the art should also understand that these equivalent constructions do not deviate from the spirit and scope of this disclosure, and they can make various changes, replacements, and changes without departing from the spirit and scope of this disclosure.

100, 400: piezoelectric ceramic device

300, 600: piezoelectric ceramic device after sealing

110: upper electrode layer

120: Lower electrode layer

130: piezoelectric ceramic material layer

140: flexible printed circuit board

142, 144: contact pad

150: conductive adhesive

160: pressure sensitive adhesive layer

170: Three anti-adhesive layer

210: vacuum pump

220: Workbench

230: soft rubber

240: Lower table

250: heating system

260: Sealing film

From the following detailed description made in conjunction with the attached drawings, we can have a better understanding of the present disclosure. It should be noted that according to industry standard practices, the features are not drawn to scale. In fact, in order to make the discussion clearer, the size of each feature can be arbitrarily increased or decreased. FIG. 1 is a cross-sectional view of a piezoelectric ceramic device according to the first embodiment of the present disclosure. [FIG. 2A] to [FIG. 2B] are schematic diagrams of the sealing process of the piezoelectric ceramic device according to the first embodiment of the present disclosure. 3 is a cross-sectional view of the piezoelectric ceramic device after sealing according to the first embodiment of the present disclosure. 4 is a cross-sectional view of a piezoelectric ceramic device according to a second embodiment of the present disclosure. [FIG. 5] A schematic view of a sealant of a piezoelectric ceramic device according to the second embodiment of the present disclosure. 6 is a cross-sectional view of a piezoelectric ceramic device after sealing according to the second embodiment of the present disclosure.

600: Piezoelectric ceramic device after sealing

110: upper electrode layer

120: Lower electrode layer

130: piezoelectric ceramic material layer

140: flexible printed circuit board

142, 144: contact pad

150: conductive adhesive

160: pressure sensitive adhesive layer

170: Three anti-adhesive layer

Claims (8)

A piezoelectric ceramic device includes: an upper electrode layer; a lower electrode layer; a piezoelectric ceramic material layer sandwiched between the upper electrode layer and the lower electrode layer; a conformal coating (CC) layer , Arranged on the left and right sides of the piezoelectric ceramic material layer; and a pressure sensitive adhesive (Pressure Sensitive Adhesive PSA) layer, covering the upper electrode layer and the three adhesive layer; wherein the Young's modulus of the three adhesive layer (Young's Modulus) is greater than 1 GPa. The piezoelectric ceramic device as described in item 1 of the patent application scope further includes: a flexible printed circuit board (FPC); wherein the lower electrode layer is bonded to the flexible printed circuit through a conductive adhesive (Conductive Adhesive) On the circuit board. The piezoelectric ceramic device as described in item 2 of the patent application scope, wherein the three adhesive layers are provided on the flexible printed circuit board, and the pressure-sensitive adhesive layer covers the flexible printed circuit board. The piezoelectric ceramic device as described in item 1 of the patent application, wherein the shape of the three adhesive layers in the cross section is a triangle, so that the plurality of turning angles of the pressure-sensitive adhesive layer are all greater than 100 degrees . A method for forming a piezoelectric ceramic device includes: providing a piezoelectric ceramic material layer sandwiched between an upper electrode layer and a lower electrode layer; performing a dispense process to make a three-layer anti-adhesive layer The left and right sides of the piezoelectric ceramic material layer; and an encapsulating process is performed to make a pressure sensitive adhesive layer cover the upper electrode layer and the three anti-adhesive layer; wherein the Young's mold of the three anti-adhesive layer The number system is greater than 1GPa. The method for forming a piezoelectric ceramic device as described in item 5 of the scope of the patent application further includes: before performing the dispensing process, through a spray process to make an anisotropic conductive adhesive (ACA) ) Distributed on a flexible printed circuit board; and performing a bonding process to bond the lower electrode layer to the flexible printed circuit board through the anisotropic conductive adhesive. The method for forming a piezoelectric ceramic device as described in item 6 of the patent application scope, wherein the three anti-adhesive layers are provided on the flexible printed circuit board Above, wherein the pressure sensitive adhesive layer covers the flexible printed circuit board. The method for forming a piezoelectric ceramic device as described in item 5 of the patent application scope, wherein the shape of the three adhesive layers in the cross section is a triangle, so that the plurality of turning angles of the pressure-sensitive adhesive layer are all greater than 100 degrees.

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