Piezoelectric diaphragm, diaphragm pump, manufacturing method for the same, and liquid discharge device

Abstract

To provide a piezoelectric diaphragm capable of suppressing an influence of thermal energy when connecting a lead to an electrode of a piezoelectric element on an adhesive for bonding another electrode of the piezoelectric element and a metal plate.SOLUTION: A piezoelectric diaphragm 1 includes: a piezoelectric element 2; and a metal plate 3 on which the piezoelectric element 2 is laminated. Electrodes 6a and 6b are provided on both surfaces 2a and 2b of the piezoelectric element 2, respectively. The electrode 6a provided on one surface 2a of the piezoelectric element 2 is bonded to the metal plate 3. A lead 8b is connected to the electrode 6b provided on the other surface 2b of the piezoelectric element 2. The electrode 6a provided on the one surface 2a of the piezoelectric element 2 is bonded to the metal plate 3 by a heat-resistant adhesive 4 in a region including a position overlapping with a connection part between the electrode 6b on the other surface 2b and the lead 8b in a plan view, and is bonded to the metal plate 3 by the conductive adhesive 5 in at least a part of a part other than the region.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a piezoelectric diaphragm, a diaphragm pump, a method for manufacturing the same, and a liquid ejection device. [Background technology]

[0002] A piezoelectric diaphragm used as a power source for a micropump or the like includes a piezoelectric element with electrodes on both sides and a metal plate to which the electrode on one side of the piezoelectric element is bonded. When power is supplied to the piezoelectric element from the electrodes, the piezoelectric element and the metal plate vibrate together. Typically, a lead for supplying power is connected to the electrode on the other side of the piezoelectric element by soldering or the like. However, thermal energy generated during connection by soldering or the like can damage the piezoelectric element. Therefore, in the invention described in Patent Document 1, a notch is formed in the electrode of the piezoelectric element opposite the electrode to which the lead is connected, at a position that overlaps the connection portion in a plan view. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-165993 Summary of the Invention [Problem to be solved by the invention]

[0004] By forming a notch in the electrode as in Patent Document 1, migration and short circuits between the electrodes can be suppressed when cracks occur in the piezoelectric element due to thermal energy during connection, such as soldering. However, even with the configuration in Patent Document 1, the thermal energy during connection can damage the adhesive that bonds the electrode on one side of the piezoelectric element to the metal plate, and it cannot prevent the adhesive strength from decreasing. If the adhesive strength between the electrode on one side of the piezoelectric element and the metal plate decreases, the lead soldered to the metal plate becomes more likely to peel off when a tensile force is applied to the lead.

[0005] The object of the present invention is to provide a piezoelectric vibration plate that can reduce the effect of thermal energy generated when connecting leads to electrodes of a piezoelectric element on the adhesive that bonds other electrodes of the piezoelectric element to a metal plate. [Means for solving the problem]

[0006] The piezoelectric diaphragm of the present invention includes a piezoelectric element and a metal plate on which the piezoelectric element is laminated, and has an electrode provided on each of both sides of the piezoelectric element, the electrode provided on one side of the piezoelectric element being adhered to the metal plate, and a lead being connected to the electrode provided on the other side of the piezoelectric element, and the electrode provided on one side of the piezoelectric element is adhered to the metal plate with a heat-resistant adhesive in a region including a position that overlaps, in a plan view, with the connection portion between the electrode on the other side and the lead, and is adhered to the metal plate with a conductive adhesive in at least a portion of the portion other than that region. [Effects of the Invention]

[0007] The piezoelectric diaphragm of the present invention can suppress the influence of thermal energy generated when connecting leads to electrodes of a piezoelectric element on the adhesive that bonds other electrodes of the piezoelectric element to a metal plate. [Brief explanation of the drawings]

[0008] [Figure 1] 1A and 1B are a plan view and a cross-sectional view showing a piezoelectric diaphragm according to a first embodiment of the present invention. [Figure 2] 2A and 2B are a plan view and a cross-sectional view showing a piezoelectric element of the piezoelectric diaphragm shown in FIG. [Figure 3] 2A and 2B are a plan view and a cross-sectional view showing a metal plate to which an adhesive material is applied, of the piezoelectric diaphragm shown in FIG. 1. [Figure 4] 2A and 2B are a plan view and a cross-sectional view showing a state in which a piezoelectric element of the piezoelectric diaphragm shown in FIG. 1 and a metal plate are bonded together. [Figure 5] 5A and 5B are a plan view and a cross-sectional view showing a piezoelectric diaphragm according to a second embodiment of the present invention. [Figure 6] 6A and 6B are a plan view and a cross-sectional view showing a metal plate to which an adhesive material is applied, of the piezoelectric diaphragm shown in FIG. 5. [Figure 7] 10A and 10B are a plan view and a cross-sectional view showing a piezoelectric diaphragm according to a third embodiment of the present invention. [Figure 8] 8A and 8B are a plan view and a cross-sectional view showing a metal plate to which an adhesive material is applied, of the piezoelectric diaphragm shown in FIG. 7. [Figure 9] 8A and 8B are a plan view and a cross-sectional view showing a state in which a piezoelectric element of the piezoelectric diaphragm shown in FIG. 7 is bonded to a metal plate. [Figure 10] 8A and 8B are a plan view and a cross-sectional view showing the soldered state of the piezoelectric diaphragm shown in FIG. 7. [Figure 11] 8A and 8B are a plan view and a cross-sectional view showing a state in which a diaphragm is attached to the piezoelectric diaphragm shown in FIG. 7. [Figure 12] 10A and 10B are a plan view and a cross-sectional view showing a piezoelectric diaphragm according to a fourth embodiment of the present invention. [Figure 13] 13A and 13B are a plan view and a cross-sectional view showing a metal plate to which an adhesive material is applied, of the piezoelectric diaphragm shown in FIG. 12. [Figure 14] 13A and 13B are a plan view and a cross-sectional view showing a state in which a piezoelectric element of the piezoelectric diaphragm shown in FIG. 12 is bonded to a metal plate. [Figure 15] 13A and 13B are a plan view and a cross-sectional view showing the soldered state of the piezoelectric diaphragm shown in FIG. 12. [Figure 16] 13A and 13B are a plan view and a cross-sectional view showing a state in which a diaphragm is attached to the piezoelectric diaphragm shown in FIG. 12. [Figure 17] 1A and 1B are a perspective view and a cross-sectional view of a diaphragm pump according to the present invention; [Figure 18] FIG. 18 is an exploded perspective view of the diaphragm pump shown in FIG. 17. [Figure 19] 1 is a schematic perspective view showing an example of the configuration of a liquid ejection device according to the present invention. [Figure 20] FIG. 20 is a perspective view of a liquid ejection head of the liquid ejection device shown in FIG. [Figure 21] FIG. 2 is a block diagram schematically illustrating a circulation path of the entire liquid ejection device. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First Embodiment FIG. 1(A) is a plan view showing a piezoelectric diaphragm 1 according to a first embodiment of the present invention, and FIG. 1(B) is a cross-sectional view taken along line AA in FIG. 1(A). FIG. 2(A) is a plan view showing a piezoelectric element 2 having electrodes 6a and 6b on both sides thereof, and FIG. 2(B) is a cross-sectional view taken along line AA in FIG. 2(A). FIG. 3(A) is a plan view showing a metal plate 3 to which two types of adhesives 4 and 5 have been applied, and FIG. 3(B) is a cross-sectional view taken along line AA in FIG. 3(A). FIG. 4(A) is a plan view showing the state in which the piezoelectric element 2 and the metal plate 3 are bonded, and FIG. 4(B) is a cross-sectional view taken along line AA in FIG. 4(A). The piezoelectric diaphragm 1 according to this embodiment includes a piezoelectric element 2 and a metal plate 3 on which the piezoelectric element 2 is laminated. The piezoelectric element 2 is made of, for example, piezoelectric ceramic, and has electrodes 6a and 6b made of a conductive paste such as silver paste on both sides 2a and 2b, respectively. An electrode 6a provided on one surface (back surface) 2a of the piezoelectric element 2 and the surrounding surface 2a are bonded to a metal plate 3. Leads 8a and 8b are connected to the metal plate 3 and an electrode 6b provided on the other surface (front surface) 2b of the piezoelectric element 2 by solders 7a and 7b, respectively. Soldering is performed using a soldering iron 12 (see FIGS. 10 and 15) or a laser, etc.

[0010] The electrode 6a provided on one surface 2a of the piezoelectric element 2 is adhered to the metal plate 3 by a heat-resistant adhesive 4 in a region including a position where it overlaps with the connection portion between the electrode 6b provided on the other surface 2b and the lead 8b in a plan view. The electrode 6a is adhered to the metal plate 3 by a conductive adhesive 5 in a region other than the overlapping region. In this specification, a plan view refers to a state when viewed in a direction perpendicular to the main surface of a plate-like member or the like. An example of the conductive adhesive 5 is a conductive adhesive having a volume resistivity of 6×10 -3The heat-resistant adhesive 4 is a thermosetting conductive acrylic adhesive with a resistance of Ω·cm. The heat-resistant adhesive 4 is generally non-conductive and has better heat resistance than the conductive adhesive 5, preferably withstanding temperatures of at least 200°C. As an example, the heat-resistant adhesive 4 is an epoxy-based adhesive that is heat-resistant to 200°C. In this embodiment, the planar shape of the solder 7b connecting the electrode 6b and the lead 8b provided on the other surface (front surface) 2b is an approximately circular shape with a diameter of approximately 3 mm. The planar shape of the heat-resistant adhesive 4 (the planar shape of the area to which the heat-resistant adhesive 4 is applied) is an approximately square shape with each side measuring 4.5 mm × 4.5 mm, 1.5 times the diameter of the planar shape of the solder 7b.

[0011] To manufacture this piezoelectric diaphragm 1, first, a piezoelectric element 2 having electrodes 6a and 6b on both sides 2a and 2b is prepared, as shown in FIGS. 2(A) and 2(B). Then, as shown in FIGS. 3(A) and 3(B), a heat-resistant adhesive 4 and a conductive adhesive 5 are applied to one side of a metal plate 3. The heat-resistant adhesive 4 is applied to a substantially square area of ​​the metal plate 3, as viewed from above, that overlaps with a portion where the electrode 6b on the other side 2b of the piezoelectric element 2 will be connected to the lead 8b in a subsequent process. The conductive adhesive 5 is applied to the remaining portion of the metal plate 3. A gap may be formed between the heat-resistant adhesive 4 and the conductive adhesive 5, or the heat-resistant adhesive 4 and the conductive adhesive 5 may be in contact with each other without a gap. Then, as shown in FIGS. 4(A) and 4(B), one side 2a of the piezoelectric element 2 is superimposed on and bonded to the metal plate 3 to which the heat-resistant adhesive 4 and the conductive adhesive 5 have been applied. Then, lead 8a is connected to metal plate 3 with solder 7a, and lead 8b is connected to electrode 6b provided on the other surface 2b of piezoelectric element 2 with solder 7b. Either lead 8a or lead 8b can be connected first. In this manner, piezoelectric diaphragm 1 shown in FIGS. 1(A) and 1(B) is manufactured. By bonding metal plate 3 and electrode 6a on one surface 2a of piezoelectric element 2 with heat-resistant adhesive 4 and conductive adhesive 5, the influence of thermal energy generated when connecting lead 8b to electrode 6b on the other surface 2b on the bonding between electrode 6a and metal plate 3 is reduced. This point will be explained below.

[0012] A comparative example is a configuration in which the metal plate 3 and the piezoelectric element 2 are bonded only with a conductive adhesive 5. In this comparative example, after bonding the metal plate 3 to the electrode 6a on one surface 2a of the piezoelectric element 2, if a lead 8b is connected to the electrode 6b on the other surface 2b with solder 7b, the thermal energy during soldering is transferred to the conductive adhesive 5 via the electrode 6b, the piezoelectric element 2, and the electrode 6a. This may result in thermal damage to the conductive adhesive 5 and a decrease in adhesive strength. For example, when soldering the lead 8b to the electrode 6b using lead-free solder 7b, the tip of the soldering iron 12 (see FIGS. 10 and 15) is approximately 340°C, and the soldering iron 12 is in contact with the lead 8b and electrode 6b for approximately 0.5 seconds. If the thermal energy of soldering performed under these conditions is transferred to the conductive adhesive 5, the adhesive strength will decrease. This decrease in adhesive strength affects the ease with which the leads 8a and 8b peel off when a tensile force is applied to them, and this may result in the conduction of the leads 8a and 8b being interrupted during transportation during the manufacture of the piezoelectric diaphragm 1, causing poor electrical connection.

[0013] In contrast, in the piezoelectric diaphragm 1 of this embodiment, a notch is provided in the conductive adhesive 5 in a region overlapping the connection between the electrode 6b and the lead 8b by the solder 7b in a plan view, and the heat-resistant adhesive 4 is disposed in that region. With this configuration, substantially the entire surface of the electrode 6a provided on one surface 2a of the piezoelectric element 2 is adhered to the metal plate 3 by the two types of adhesives 4 and 5, thereby providing a strong fixation. Furthermore, when soldering the electrode 6b on the other surface 2b to the lead 8b, the heat-resistant adhesive 4 is primarily transmitted via the electrode 6b, the piezoelectric element 2, and the electrode 6a through the heat-resistant adhesive 4. The heat-resistant adhesive 4 is hardly damaged by the application of heat energy, and its adhesive strength is not easily reduced. Furthermore, while the heat-resistant adhesive 4 is generally non-conductive, in this embodiment, the conductive adhesive 5 ensures electrical connection between the electrode 6a and the metal plate 3. As described above, according to this embodiment, the combined use of the heat-resistant adhesive 4 and the conductive adhesive 5 enables a strong bond and electrical connection between the electrode 6a and the metal plate 3. Furthermore, because the heat-resistant adhesive 4 bonds the electrode 6a to the metal plate 3 in the area where the thermal energy generated by soldering is primarily transmitted, the adhesive strength is prevented from decreasing due to the influence of thermal energy, and peeling is unlikely to occur even when a tensile force is applied to the leads 8a and 8b. For example, if the temperature of the tip of the soldering iron 12 (see FIGS. 10 and 15 ) is approximately 340°C, the temperature of the heat-resistant adhesive 4, through which thermal energy is transmitted via the electrode 6b, the piezoelectric element 2, and the electrode 6a, is expected to be approximately 150°C. Therefore, the heat-resistant adhesive 4, which has a heat resistance of approximately 200°C, is hardly damaged by heat. Furthermore, because the conductive adhesive 5 ensures electrical connection between the electrode 6a and the metal plate 3, the supply of power and electrical signals to the piezoelectric element 2 via the leads 8a and 8b is highly reliable while keeping manufacturing costs low. Note that the soldering for connecting the electrode 6a on one surface 2a of the piezoelectric element 2 to the lead 8a with the solder 7a is performed at a position away from the conductive adhesive 5, so that the thermal energy during soldering is not transmitted very much to the conductive adhesive 5. Therefore, the conductive adhesive 5 is hardly damaged by the thermal energy during soldering. Note that in the example shown in Fig. 3, the planar shape of the area where the heat-resistant adhesive 4 is provided is approximately square.However, the present invention is not limited to such a configuration, and the planar shape of the area where the heat-resistant adhesive 4 is provided may be a circle, a polygonal shape other than a square, or any other shape.

[0014] <Second embodiment> Next, a piezoelectric diaphragm 1 according to a second embodiment of the present invention will be described. FIG. 5(A) is a plan view showing the piezoelectric diaphragm 1 according to the second embodiment of the present invention, and FIG. 5(B) is a cross-sectional view taken along line AA in FIG. 5(A). FIG. 6(A) is a plan view showing the metal plate 3 to which two types of adhesives 4 and 5 of the piezoelectric diaphragm 1 have been applied, and FIG. 6(B) is a cross-sectional view taken along line AA in FIG. 6(A). In the second embodiment of the present invention, the area to which the heat-resistant adhesive 4 is applied has a ring-like shape that overlaps with the connection between the electrode 6b and the lead 8b by the solder 7b in plan view. In plan view, a conductive adhesive 5 is provided inside the ring-shaped heat-resistant adhesive 4 formed on the metal plate 3. The other configurations are the same as those in the first embodiment, so the same reference numerals are used and their description will be omitted.

[0015] In the present invention, it is necessary to align the solder 7b electrically connecting the electrode 6b and the lead 8b so that it is located within the area where the heat-resistant adhesive 4 is provided in a plan view. In this embodiment, the heat-resistant adhesive 4 has a ring-like planar shape, so circumferential alignment of the solder 7b is not necessary. The heat-resistant adhesive 4 preferably has a ring-like planar shape concentric with the outer shapes of the electrodes 6a and 6b. In one example, the width of the ring, which is the planar shape of the heat-resistant adhesive 4, is 4.5 mm, which is 1.5 times the diameter (3 mm) of the planar shape of the solder 7b. This configuration, as in the first embodiment, enables strong adhesion between the electrode 6a and the metal plate 3 and prevents a decrease in adhesive strength due to thermal energy during soldering between the electrode 6b and the lead 8b. Furthermore, peeling of the leads 8a and 8b when a tensile force is applied is suppressed, and the electrical connection between the electrode 6a and the metal plate 3 is ensured by the conductive adhesive 5. This reduces manufacturing costs and increases the reliability of the supply of power and electrical signals to the piezoelectric element 2. In this embodiment, the heat-resistant adhesive 4 is formed in a ring shape, eliminating the need for circumferential alignment when soldering the lead 8b to the electrode 6b, making the soldering process easier. Furthermore, the conductive adhesive 5 is surrounded by the ring-shaped heat-resistant adhesive 4, reducing the transfer of thermal energy to the surrounding area during soldering. In the configuration shown in FIGS. 5 and 6, the heat-resistant adhesive 4 has a complete ring-like shape in plan view. However, a configuration may also be adopted in which a notch is cut out in a portion of the ring (not shown), and the conductive adhesive 5 is disposed in the notch. This reduces costs.

[0016] <Third embodiment> Next, a piezoelectric diaphragm 1 according to a third embodiment of the present invention will be described. Fig. 7(A) is a plan view showing the piezoelectric diaphragm 1 according to the third embodiment of the present invention, and Fig. 7(B) is a cross-sectional view taken along line AA in Fig. 7(A). Fig. 8(A) is a plan view showing a metal plate 3 to which a conductive adhesive 5 is applied, and Fig. 8(B) is a cross-sectional view taken along line AA in Fig. 8(A). Fig. 9(A) is a plan view showing a state in which a piezoelectric element 2 and a metal plate 3 are bonded, and Fig. 9(B) is a cross-sectional view taken along line AA in Fig. 9(A). Fig. 10(A) is a plan view showing a state in which a lead 8b is soldered to an electrode 6b provided on the other surface 2b of the piezoelectric element 2, and Fig. 10(B) is a cross-sectional view taken along line AA in Fig. 10(A). Fig. 11(A) is a plan view showing a state in which a diaphragm 14 is attached to the piezoelectric diaphragm 1 according to this embodiment, and Fig. 11(B) is a cross-sectional view taken along line AA in Fig. 11(A). Similar to the piezoelectric diaphragm 1 of the first embodiment, the piezoelectric diaphragm 1 of this embodiment includes a piezoelectric element 2 and a metal plate 3 on which the piezoelectric element 2 is laminated. Electrodes 6a and 6b are provided on both surfaces 2a and 2b of the piezoelectric element 2, respectively. The electrode 6a provided on one surface (back surface) 2a of the piezoelectric element 2 and the surrounding surface 2a are bonded to the metal plate 3. Leads 8a and 8b are connected to the metal plate 3 and the electrode 6b provided on the other surface (front surface) 2b of the piezoelectric element 2 by solders 7a and 7b, respectively. The materials of the piezoelectric element 2, the electrodes 6a and 6b, and the metal plate 3 may be the same as those of the first embodiment.

[0017] An opening 9 is provided in the metal plate 3 in a region including a position overlapping the connection portion between the electrode 6b and the lead 8b provided on the other surface 2b in a plan view, and a rib 11 is provided inside the opening 9. The electrode 6a provided on one surface 2a of the piezoelectric element 2 is adhered to the metal plate 3 with a conductive adhesive 5 in a portion other than the position facing the opening 9 of the metal plate 3 and in a portion facing the rib 11 in a plan view. The portion of the one surface 2a facing the opening 9 but excluding the position facing the rib 11 is adhered to the metal plate 3 with an adhesive 10 inside the opening 9. The conductive adhesive 5 may be the same as in the first embodiment. The adhesive 10 inside the opening 9 does not need to be heat-resistant and may be the same adhesive as the conductive adhesive 5 or a different adhesive. As an example, the planar shape of the solder 7b connecting the electrode 6b and the lead 8b is a substantially circular shape with a diameter of about 3 mm, and the planar shape of the opening 9 provided in the metal plate is a substantially square shape with each side measuring 4.5 mm x 4.5 mm, which is 1.5 times the diameter of the planar shape of the solder 7b. The planar shape of the rib 11 is a straight line passing through approximately the center of the planar shape of the opening 9, and the width of the rib 11 may be about 1.5 mm, the same as the diameter of the solder 7b.

[0018] To manufacture this piezoelectric diaphragm 1, a piezoelectric element 2 having electrodes 6a and 6b formed on both surfaces 2a and 2b, respectively, is prepared, similar to the piezoelectric element 2 of the first embodiment shown in FIGS. 2(A) and 2(B). Also, as shown in FIGS. 8(A) and 8(B), a metal plate 3 having an opening 9 and a rib 11 is prepared. Specifically, two holes are formed side by side in the metal plate 3 by a punching process or the like, thereby forming a substantially square opening 9 and a linear rib 11 passing through the center of the opening 9. In this specification, a configuration in which two holes are formed side by side in this manner is considered to be a configuration in which one rib 11 is provided within one opening 9. A conductive adhesive 5 is applied to one surface of the metal plate 3. The conductive adhesive 5 is provided on the metal plate 3 in the areas other than the opening 9 and on the rib 11. The conductive adhesive 5 is not present in the areas of the opening 9 other than the rib 11. As shown in FIGS. 9(A) and 9(B), one surface 2a of the piezoelectric element 2 is placed on and bonded to the metal plate 3 to which the conductive adhesive 5 has been applied. Then, a lead 8a is connected to the metal plate 3 with solder 7a, and a lead 8b is connected to an electrode 6b on the other surface 2b of the piezoelectric element 2 with solder 7b. When connecting the lead 8b to the electrode 6b with solder 7b, as shown in FIGS. 10(A) and 10(B), the solder 7b is heated and fixed with a soldering iron 12 facing the rib 11. Even if the soldering iron 12 comes into contact with and presses the solder 7b, the piezoelectric element 2 is supported from one surface 2a side (the lower side in the drawing) by the rib 11, so that damage such as cracks is suppressed. If the width of the flat contact portion of the tip of the soldering iron 12 is approximately 0.8 mm and the width of the rib 11 is approximately 1.5 mm, the rib 11 can adequately support the piezoelectric element 2 and solder 7b during soldering without strict control of the positional accuracy of the soldering iron 12. After the lead 8b is connected to the electrode 6b by the solder 7b, a space is created at the position of the opening 9 below the solder 7b. This space is open on the side of one surface 2a (the bottom side of the drawing). By injecting adhesive 10 into the opening 9 from the side of one surface 2a (the bottom side of the drawing) and solidifying it, the adhesive 10 bonds a portion of the electrode 6b to a portion of the metal plate 3. Thus, the electrode 6b and the metal plate 3 are firmly bonded together by the conductive adhesive 5 and adhesive 10.

[0019] In this embodiment, an opening 9 is provided in a region including a position overlapping the connection portion between the electrode 6b and the lead 8b. The opening 9 is free of adhesive 10, leaving an open space, and soldering is performed to connect the electrode 6b and the lead 8b. After soldering is completed, adhesive 10 is injected into the opening 9. Therefore, thermal energy during soldering is not transferred to the adhesive 10, and the adhesive 10 is not damaged by heat. Furthermore, since most of the conductive adhesive 5 is located away from the connection portion between the electrode 6b and the lead 8b, the thermal energy during soldering is not transferred very much, and thermal damage is minimal. The conductive adhesive 5 applied to the rib 11 may be damaged by the thermal energy transferred during soldering. However, since the rib 11 has a small area, only a small amount of the conductive adhesive 5 is damaged by the thermal energy transferred, and therefore the impact on the adhesive strength between the electrode 6b and the metal plate 3 is negligible. Other than the above, the other aspects are similar to those of the first and second embodiments, and therefore further description is omitted.

[0020] As described above, in this embodiment, as in the first embodiment, strong adhesion between the electrode 6a and the metal plate 3 is possible, and a decrease in adhesive strength due to thermal energy is suppressed. Furthermore, peeling is unlikely to occur even when a tensile force is applied to the leads 8a, 8b, and the electrical connection between the electrode 6b and the metal plate 3 is ensured by the conductive adhesive 5, so manufacturing costs are kept low and the supply of power and electrical signals to the piezoelectric element 2 is highly reliable. Moreover, there is no need to use a heat-resistant adhesive, and the adhesive 10 injected into the opening 9 may be the same adhesive as the conductive adhesive 5 or a different adhesive, so costs related to adhesives can be reduced.

[0021] When the piezoelectric diaphragm 1 of this embodiment is used in a diaphragm pump or the like, which will be described later, a diaphragm 14 is fixed to a metal plate 3, as shown in Figures 11(A) and 11(B). A portion of the adhesive 10 for fixing the diaphragm 14 can be poured into the opening 9 as described above and used to bond the electrode 6b, the metal plate 3, and the diaphragm 14. In other words, the adhesive 10 used for fixing the diaphragm can be reused to obtain the effects described above, and manufacturing costs can be kept low.

[0022] <Fourth embodiment> Next, a piezoelectric diaphragm 1 according to a fourth embodiment of the present invention will be described. Fig. 12(A) is a plan view showing the piezoelectric diaphragm 1 according to the fourth embodiment of the present invention, and Fig. 12(B) is a cross-sectional view taken along line AA in Fig. 12(A). Fig. 13(A) is a plan view showing a metal plate 3 to which a conductive adhesive 5 is applied, and Fig. 13(B) is a cross-sectional view taken along line AA in Fig. 13(A). Fig. 14(A) is a plan view showing a state in which a piezoelectric element 2 and a metal plate 3 are bonded, and Fig. 14(B) is a cross-sectional view taken along line AA in Fig. 14(A). Fig. 15(A) is a plan view showing a state in which a lead 8b is soldered to an electrode 6b of a piezoelectric element 2, and Fig. 15(B) is a cross-sectional view taken along line AA in Fig. 15(A). Fig. 16(A) is a plan view showing a state in which a diaphragm 14 is attached to the piezoelectric diaphragm 1 according to this embodiment, and Fig. 16(B) is a cross-sectional view taken along line AA in Fig. 16(A). This embodiment differs from the third embodiment in that no rib is provided inside the opening 9 of the metal plate 3. Since the other configurations are the same as those of the third embodiment, the same reference numerals are used and the description will be omitted.

[0023] In this embodiment, an opening 9 is provided in a region of the metal plate 3 that includes a position that overlaps, in plan view, the connection portion between the electrode 6b and the lead 8b provided on the other surface 2b, and no rib or the like is provided inside the opening 9. The electrode 6a provided on one surface 2a of the piezoelectric element 2 is bonded to the metal plate 3 with a conductive adhesive 5 in a portion other than the position facing the opening 9 of the metal plate 3 in plan view. The electrode 6a is bonded to the metal plate 3 at the position facing the opening 9 on the one surface 2a with an adhesive 10 injected into the opening 9. The conductive adhesive 5 may be the same as in the first embodiment, and the adhesive 10 injected into the opening 9 may be the same as in the third embodiment. The planar shapes of the solder 7b and the opening 9 may be the same as in the third embodiment.

[0024] To manufacture this piezoelectric diaphragm 1, a piezoelectric element 2 similar to those in the first to third embodiments is prepared, and a metal plate 3 having an opening 9 as shown in FIGS. 13(A) and 13(B) is prepared. Specifically, a substantially square opening 9 is formed in the metal plate 3 by punching or the like. A conductive adhesive 5 is provided on one surface of the metal plate 3 except for the opening 9. No conductive adhesive 5 is present within the opening 9. One surface 2a of the piezoelectric element 2 is then superimposed and bonded to the metal plate 3 to which the conductive adhesive 5 has been applied, as shown in FIGS. 14(A) and 14(B). Then, a lead 8a is connected to the metal plate 3 with solder 7a, and a lead 8b is connected to an electrode 6b on the other surface 2b of the piezoelectric element 2 with solder 7b. When connecting the lead 8b to the electrode 6b with solder 7b, a rectangular parallelepiped support jig 13 is inserted into the opening 9 from the side of one surface 2a (the lower side of the drawing), and passes through the opening 9 to abut against the electrode 6b, as shown in FIGS. 15(A) and 15(B). That is, the piezoelectric element 2 is supported from one surface 2a (the lower side of the drawing) by a support jig 13. In this state, a soldering iron 12 is brought into contact with the solder 7b covering a portion of the lead 8b on the electrode 6b, and heat is applied to fix the solder 7b. Even if the soldering iron 12 contacts and presses the solder 7b, the piezoelectric element 2 is supported from one surface 2a (the lower side of the drawing) by the support jig 13, so that damage such as cracks is suppressed. After the lead 8b is connected to the electrode 6b by the solder 7b in this manner, the support jig 13 is removed from the opening 9. Then, adhesive 10 is poured into the opening 9 from one surface (the lower side of the drawing) so as to fill the space that is created at the position of the opening 9 below the solder 7b and open to the one surface 2a (the lower side of the drawing), and is solidified. The adhesive 10 bonds a part of the electrode 6b to a part of the metal plate 3, and the conductive adhesive 5 and adhesive 10 firmly bond the electrode 6b to the metal plate 3.

[0025] In this embodiment, the adhesive 10 is injected into the opening 9 after soldering to connect the electrode 6b and the lead 8b. Therefore, the adhesive 10 is not affected by the thermal energy during soldering. Therefore, the same effects as those of the third embodiment can be achieved in this embodiment. Furthermore, since there is no rib in the opening 9 in this embodiment, neither the conductive adhesive 5 nor the adhesive 10 is present in the opening 9 at the time of soldering. Therefore, the conductive adhesive 5 and the adhesive 10 are less likely to be affected by the thermal energy during soldering when connecting the electrode 6b and the lead 8b. In this embodiment, the piezoelectric diaphragm 1 can also be used in a diaphragm pump. As shown in FIGS. 16(A) and 16(B), a portion of the adhesive 10 that secures the diaphragm 14 can be injected into the opening 9 and used to bond the electrode 6b, the metal plate 3, and the diaphragm 14.

[0026] In any of the first to fourth embodiments described above, soldering, which is an inexpensive and common electrical connection method, can be performed while preventing almost no damage caused by thermal energy to the piezoelectric element 2 and adhesive materials 4, 5, and 10. As a result, it is possible to prevent a decrease in the adhesive strength between the electrode 6a and the metal plate 3 and peeling when a tensile force is applied to the leads 8a and 8b.

[0027] <Diaphragm pump> A diaphragm pump, which is an example of a device employing a piezoelectric diaphragm 1 according to the present invention, will be described. FIG. 17(A) is a perspective view of a diaphragm pump (hereinafter sometimes referred to as a "pump") 21 according to the present invention, and FIG. 17(B) is a cross-sectional view thereof. FIG. 18 is an exploded perspective view of the pump 21. The pump 21 includes a piezoelectric diaphragm 1 according to the present invention, a diaphragm 14, a case 22, and a flow path member 23. For clarity, the electrodes 6a and 6b, the solders 7a and 7b, and the leads 8a and 8b are omitted from FIGS. 17 and 18. The case 22 has two flow paths 24a and 24b on one side (the lower side in FIGS. 17(B) and 18) and a recess 25 having a circular planar shape on the other side (the upper side in FIGS. 17(B) and 18). The two flow paths 24a and 24b communicate with the recess 25. A flow path member 23 is bonded to one side of the case 22. Flow path member 23 is provided with two hollow pipes 26a, 26b protruding away from case 22 and with flow paths 27a, 27b communicating with the hollows in pipes 26a, 26b, respectively. When case 22 and flow path member 23 are joined, flow paths 24a, 24b of case 22 communicate with flow paths 27a, 27b of flow path member 23. For example, one pipe 26a and flow paths 27a, 24a are concentrically arranged and communicate with each other to form a suction-side path. The other pipe 26b and flow paths 27b, 24b are concentrically arranged and communicate with each other to form a discharge-side path. A suction-side check valve 28a is provided in flow path 27a, and a discharge-side check valve 28b is provided in flow path 24b on the discharge side. Check valves 28a, 28b are made of thin, plate-shaped rubber or the like and elastically deform when subjected to pressure. Case 22 and flow path member 23 are airtightly joined outside flow paths 27a and 24b, in which check valves 28a and 28b are housed. The suction-side path consisting of pipe portion 26a and flow paths 27a and 24a is opened and closed by suction-side check valve 28a. The discharge-side path consisting of pipe portion 26b and flow paths 27b and 24b is opened and closed by discharge-side check valve 28b.

[0028] Similar to the configurations shown in FIGS. 11 and 16, a diaphragm 14 is bonded to the metal plate 3 of the piezoelectric diaphragm 1 of the pump 21, and the piezoelectric diaphragm 1 is joined to the case 22 so that the diaphragm 14 closes a recess 25 in the case 22. The recess 25 is closed by the diaphragm 14 to form a pump chamber, and the diaphragm 14 serves as one of the walls that define the pump chamber. The diaphragm 14 has a protrusion 14a on its outer periphery, and the end face of the protrusion 14a (the end face at the bottom in the drawing) is fixed to the case 22, and the inside of the protrusion 14a forms a vibrating vibrating portion 14b. The recess 25 of the case 22, the protrusion 14a, and the vibrating portion 14b are formed concentrically. The projection image of the outer periphery 3a of the metal plate 3 of the piezoelectric diaphragm 1 onto the case 22 side is located between the inner periphery of the protrusion 14a (the outer periphery of the vibrating portion 14b) and the outer periphery (the outer periphery of the entire diaphragm 14).

[0029] Pump 21 uses piezoelectric diaphragm 1 according to the present invention, for example, piezoelectric diaphragm 1 having a configuration similar to any of the first to fourth embodiments described above. When piezoelectric diaphragm 1 is driven, diaphragm 14 vibrates integrally with piezoelectric element 2 and metal plate 3. When diaphragm 14 vibrates, the volume of a pump chamber formed by recess 25 increases or decreases, and the resulting pressure opens and closes suction-side check valve 28a and discharge-side check valve 28b. That is, by supplying an electrical signal to electrodes 6a, 6b (see FIGS. 1, 5, 11, 16, etc.) of piezoelectric diaphragm 1, suction-side check valve 28a opens to draw in fluid, or discharge-side check valve 28b opens to discharge fluid.

[0030] In this way, by using the piezoelectric diaphragm 1 of the present invention together with the check valves 28a and 28b, it is possible to manufacture a pump (micropump) 21 that mechanically vibrates the piezoelectric element 2 by supplying an electrical signal from the outside and pumps a minute amount of liquid using the generated pressure. This allows for a low-cost, highly reliable pump 21 to be obtained.

[0031] <Liquid ejection head and liquid ejection device> Next, a liquid ejection device 30 according to the present invention and a liquid ejection head 31 included therein will be described with reference to FIGS. 19 to 21. An example of the liquid ejection device 30 is an inkjet recording device that ejects liquid ink to perform recording, and an example of the liquid ejection head 31 included therein is an inkjet recording head. However, the liquid ejection device 30 and the liquid ejection head 31 are not limited to inkjet recording devices and inkjet recording heads. The liquid ejection device 30 of the present invention may be a device such as a printer, a copier, a facsimile machine with a communication system, or a word processor with a printer unit, or even an industrial recording device combined with various processing devices. The liquid ejection device 30 of the present invention may also be a device used for applications such as biochip production and electronic circuit printing.

[0032] 19 is a schematic perspective view illustrating an example of the configuration of a liquid ejection device 30 including a liquid ejection head 31. The liquid ejection device 30 is a so-called full-line type recording device, and has a long liquid ejection head 31 that extends across the entire width of a recording medium P. The recording medium P is continuously transported in the direction of arrow F by a transport mechanism 32 including a transport belt and the like. An image is recorded on the recording medium P by ejecting liquid ink from the liquid ejection head 31 while transporting the recording medium P in the direction of arrow F. This liquid ejection device 30 has four liquid ejection heads 31C, 31M, 31Y, and 31Bk that eject cyan (C), magenta (M), yellow (Y), and black (K) liquid ink, respectively, and is capable of recording color images.

[0033] FIG. 20 is a perspective view of a liquid ejection head 31. The liquid ejection head 31 has a configuration in which a plurality of element substrates 33 are arranged in the Y direction, and each element substrate 33 has a plurality of energy generating elements 15 (e.g., heat generating elements, see FIG. 21) arranged in the Y direction. As an example, by arranging a plurality of element substrates 33, a full-line liquid ejection head 31 is configured whose dimension in the Y direction corresponds to the width of an A4 size paper. Each element substrate 33 is connected to a common electric wiring board 35 via a flexible electric wiring board 34. The electric wiring board 35 is provided with a power supply terminal unit 36 ​​to which power is supplied and a signal input terminal unit 37 to receive an electric signal for ejection. A support member 38, which is a liquid supply unit that supports the element substrates 33 and supplies liquid, is formed with a portion of a circulation flow path (see FIG. 21) that supplies ink supplied from an ink tank (not shown) to each element substrate 33 and recovers unused ink. Each energy generating element 15 of the element substrate 33 shown in Figure 21 is driven by power supplied from the power supply terminal section 36 based on an ejection signal input from the signal input terminal section 37, and generates energy to eject ink from the ejection port 16 to the outside along the Z direction.

[0034] <Circulation route> FIG. 21 is a block diagram showing the circulation paths of liquid ink in the entire liquid ejection device 30, including the liquid ejection head 31. While FIG. 21 shows a circulation path for one color of liquid ink, in reality, circulation paths are provided for the number of colors used in the liquid ejection device 30. The liquid ejection head 31 includes a support member 38, which is a liquid supply unit, and a liquid ejection unit 40, which includes multiple element substrates 33 and a flow path member 39. The support member 38 includes a filter 41 and a negative pressure control unit 42, and is connected to a circulation pump 43 and a buffer tank 44. Liquid ink supplied from the buffer tank 44 to the liquid connection portion of the support member 38 passes through the filter 41 and the negative pressure control unit 42 in that order before being sent to the liquid ejection unit 40. The negative pressure control unit 42 is a typical regulator mechanism that has the function of maintaining a predetermined constant negative pressure downstream (toward the liquid ejection unit 40) even when the liquid supply flow rate fluctuates in accordance with changes in print duty. The support member 38 temporarily collects liquid ink from the outlet of the liquid ejection unit 40 and discharges the liquid ink to the suction side of the circulation pump 43. Inside the liquid ejection unit 40, an element substrate 33 and a flow path member 39 supporting it are stacked in the stacking direction (z direction). The flow path member 39 of the liquid ejection unit 40 receives liquid ink supplied from the support member 38. A supply flow path 45 is provided within the flow path member 39. The upstream side of the supply flow path 45 is connected to the support member 38, and the downstream side of the supply flow path 45 is connected to a common flow path 46 of the element substrate 33. That is, the supply flow path 45 has a connection port connected to the support member 38 and a connection port connected to the common flow path 46. The common flow path 46 of the element substrate 33 is a common flow path connected to multiple pressure chambers 48. A recovery flow path 47 is also provided within the flow path member 39. The upstream side of the recovery flow path 47 is connected to the common flow path 46 of the element substrate 33, and the downstream side of the recovery flow path 47 is connected to the circulation pump 43 via the support member 38. That is, the recovery flow path 47 has a connection port connected to the common flow path 46 and a connection port connected to the support member 38.

[0035] The buffer tank 44, connected to the element substrate 33 of the liquid ejection head 31, is a storage unit that stores liquid ink and has an air communication hole (not shown) through which air bubbles in the liquid ink can be discharged to the outside. The buffer tank 44 is also connected to a replenishment pump 49. When ink is consumed in the liquid ejection head 31 due to a recording operation, a suction recovery process, or the like, the replenishment pump 49 transfers the consumed ink from the main tank 50 to the buffer tank 44. The circulation pump 43 sucks ink from the liquid ejection head 31 and returns it to the buffer tank 44, and also has the function of applying a decompression force to the negative pressure control unit 42 from the downstream side of the circulation path. The circulation pump 43 and the replenishment pump 49 can be, for example, a syringe pump, a tube pump, a diaphragm pump, or a gear pump. In this example, a diaphragm pump 21 as shown in FIGS. 17 and 18 is used.

[0036] In this liquid ejection device 30, liquid ink is supplied from a main tank 50 to a plurality of pressure chambers 48 via a buffer tank 44, a support member 38, a flow path member 39, and a common flow path 46. The energy generating elements 15 of the element substrate 33 are driven at appropriate timing by an ejection signal input from a signal input terminal unit 37 and power supplied from a power supply terminal unit 36. The driven energy generating elements 15 then receive energy generated, causing the liquid ink in the pressure chambers 48 to be ejected as droplets from the ejection ports 16 to the outside of the liquid ejection head 31.

[0037] In the liquid ejection device 30 shown in Fig. 21, a diaphragm pump 21 (such as the pumps shown in Figs. 17 and 18) using the piezoelectric diaphragm 1 of the present invention, for example, the piezoelectric diaphragm 1 of the first to fourth embodiments described above, is used as a circulation pump 43 and a replenishment pump 49. This allows for the incorporation of a low-cost, highly reliable pump 21, resulting in a liquid ejection device 30 that can stably perform good liquid ejection operations. However, the liquid ejection device 30 incorporating the piezoelectric diaphragm 1 and diaphragm pump 21 of the present invention is not limited to the configuration shown in Fig. 21, and the piezoelectric diaphragm 1 and diaphragm pump 21 of the present invention can be suitably employed in any liquid ejection device that implements various ejection methods.

[0038] As explained above, the piezoelectric diaphragm 1 of the present invention is preferably used as the actuation source for the diaphragm pump 21, and furthermore, by incorporating this diaphragm pump 21 as the circulation pump 43 and the refill pump 49, an inexpensive and highly reliable liquid discharge device 30 can be configured. However, the piezoelectric diaphragm 1 of the present invention is not limited to such uses. For example, the piezoelectric diaphragm 1 of the present invention can also be preferably used in the piezoelectric sounding body described in Patent Document 1 and various other devices.

[0039] The present invention may include the following configurations and methods. (device 1) a piezoelectric element and a metal plate on which the piezoelectric element is laminated, Electrodes are provided on both sides of the piezoelectric element, the electrode provided on one surface of the piezoelectric element is bonded to the metal plate, a lead is connected to the electrode provided on the other surface of the piezoelectric element; A piezoelectric diaphragm characterized in that the electrode provided on one surface of the piezoelectric element is adhered to the metal plate with a heat-resistant adhesive in an area including a position that overlaps the connection portion between the electrode on the other surface and the lead when viewed in a plane, and is adhered to the metal plate with a conductive adhesive in at least a portion of the area other than that area. (device 2) The piezoelectric diaphragm described in Device 1, wherein the heat-resistant adhesive is non-conductive. (device 3) The piezoelectric diaphragm according to Device 1 or 2, wherein the heat-resistant adhesive has heat resistance to a temperature of at least 200°C. (device 4) 4. The piezoelectric diaphragm according to any one of devices 1 to 3, wherein the heat-resistant adhesive has a polygonal or circular planar shape. (device 5) 4. The piezoelectric diaphragm according to any one of Devices 1 to 3, wherein the heat-resistant adhesive has a ring-shaped planar shape. (device 6) The piezoelectric diaphragm according to device 5, wherein the conductive adhesive is disposed inside the heat-resistant adhesive that is ring-shaped in a plan view. (device 7) a piezoelectric element and a metal plate on which the piezoelectric element is laminated, Electrodes are provided on both sides of the piezoelectric element, the electrode provided on one surface of the piezoelectric element is bonded to the metal plate, a lead is connected to the electrode provided on the other surface of the piezoelectric element; an opening is provided in the metal plate in a region including a position overlapping a connection portion between the electrode and the lead on the other surface in a plan view; A piezoelectric vibration plate characterized in that the electrode provided on one surface of the piezoelectric element is adhered to the metal plate by an adhesive inside the opening at a position facing the opening in a planar view, and is adhered to the metal plate by a conductive adhesive in at least a portion of the portion other than the position facing the opening. (device 8) A piezoelectric vibration plate as described in device 7, wherein the metal plate has a rib inside the opening when viewed in a plane, and the rib faces the connection portion between the electrode and the lead provided on the other surface of the piezoelectric element. (device 9) 9. The piezoelectric diaphragm of device 7 or 8, wherein the adhesive inside the opening is a different adhesive from the conductive adhesive. (device 10) 10. The piezoelectric diaphragm according to any one of devices 1 to 9, wherein the electrode provided on the other surface of the piezoelectric element and the lead are connected by soldering. (device 11) A diaphragm pump comprising a piezoelectric vibration plate described in any one of devices 1 to 10, a case having a recess, and a diaphragm bonded to the metal plate of the piezoelectric vibration plate and positioned so as to cover the recess of the case. (device 12) A liquid ejection device including a liquid ejection head that ejects liquid from an ejection port, and the diaphragm pump according to device 11 that supplies liquid to the liquid ejection head. (Method 1) A method for manufacturing a piezoelectric diaphragm including a piezoelectric element and a metal plate on which the piezoelectric element is laminated, and an electrode is provided on each of both surfaces of the piezoelectric element, a step of adhering a partial region of the electrode provided on one surface of the piezoelectric element to the metal plate with a heat-resistant adhesive, and adhering at least a part of a portion other than the partial region to the metal plate with a conductive adhesive; and connecting a lead to the electrode on the other surface of the piezoelectric element at a position that overlaps with the region in a plan view. (Method 2) A method for manufacturing a piezoelectric diaphragm including a piezoelectric element and a metal plate on which the piezoelectric element is laminated, and an electrode is provided on each of both surfaces of the piezoelectric element, An opening is provided in a part of the metal plate, a step of adhering at least a portion of the electrode provided on one surface of the piezoelectric element, other than a region facing the opening in a plan view, to the metal plate using a conductive adhesive; connecting a lead to a part of a region of the electrode provided on the other surface of the piezoelectric element that faces the opening in a plan view; a step of injecting an adhesive into the opening after the step of connecting the lead, and using the adhesive to adhere an area of ​​the electrode provided on one side of the piezoelectric element that faces the opening in a planar view to the metal plate. (Method 3) The method for manufacturing a piezoelectric diaphragm described in Method 2, wherein the metal plate has a rib inside the opening when viewed in a plane, and the step of connecting the lead is performed in a state where the piezoelectric element is supported from the one surface side by the rib. (Method 4) The method for manufacturing a piezoelectric diaphragm according to method 2, wherein the step of connecting the leads is performed in a state in which the piezoelectric element is supported from the one surface side by a support jig that passes through the opening. (Method 5) 5. The method for manufacturing a piezoelectric diaphragm according to any one of methods 1 to 4, wherein in the step of connecting the leads, the leads are soldered to the electrodes. (Method 6) A step of adhering a diaphragm to the metal plate of the piezoelectric diaphragm manufactured by the method for manufacturing a piezoelectric diaphragm according to method 1; and attaching the piezoelectric diaphragm to a case having a recess so that the diaphragm closes the recess. (Method 7) A step of adhering a diaphragm to the metal plate of the piezoelectric diaphragm manufactured by the method for manufacturing a piezoelectric diaphragm according to any one of methods 2 to 5; and attaching the piezoelectric diaphragm to a case having a recess so that the diaphragm closes the recess. (Method 8) The method for manufacturing a diaphragm pump according to Method 7, wherein the adhesive is injected into the opening and applied to the surface of the metal plate opposite to the surface bonded to the one surface of the piezoelectric element, and the diaphragm is bonded to the metal plate by the adhesive. [Explanation of symbols]

[0040] 1 Piezoelectric diaphragm 2 Piezoelectric element 2a One side 2b The other side 3 metal plate 4 Heat-resistant adhesive 5 Conductive adhesive 6a,6b electrode 8a,8b lead

Claims

1. a piezoelectric element and a metal plate on which the piezoelectric element is laminated, Electrodes are provided on both sides of the piezoelectric element, the electrode provided on one surface of the piezoelectric element is bonded to the metal plate, a lead is connected to the electrode provided on the other surface of the piezoelectric element; A piezoelectric diaphragm characterized in that the electrode provided on one surface of the piezoelectric element is adhered to the metal plate with a heat-resistant adhesive in an area including a position that overlaps the connection portion between the electrode on the other surface and the lead when viewed in a plane, and is adhered to the metal plate with a conductive adhesive in at least a portion of the area other than that area.

2. The piezoelectric diaphragm according to claim 1 , wherein the heat-resistant adhesive is non-conductive.

3. The piezoelectric diaphragm according to claim 1 , wherein the heat-resistant adhesive has a heat resistance to a temperature of at least 200° C.

4. The piezoelectric diaphragm according to claim 1 , wherein the heat-resistant adhesive has a polygonal or circular planar shape.

5. The piezoelectric diaphragm according to claim 1 , wherein the heat-resistant adhesive has a ring-shaped planar shape.

6. The piezoelectric diaphragm according to claim 5 , wherein the conductive adhesive material is disposed inside the heat-resistant adhesive material that is ring-shaped in a plan view.

7. a piezoelectric element and a metal plate on which the piezoelectric element is laminated, Electrodes are provided on both sides of the piezoelectric element, the electrode provided on one surface of the piezoelectric element is bonded to the metal plate, a lead is connected to the electrode provided on the other surface of the piezoelectric element; an opening is provided in the metal plate in a region including a position overlapping a connection portion between the electrode and the lead on the other surface in a plan view; A piezoelectric vibration plate characterized in that the electrode provided on one surface of the piezoelectric element is adhered to the metal plate by an adhesive inside the opening at a position facing the opening in a planar view, and is adhered to the metal plate by a conductive adhesive in at least a portion of the portion other than the position facing the opening.

8. 8. The piezoelectric diaphragm according to claim 7, wherein the metal plate has a rib inside the opening in a planar view, the rib facing a connection portion between the electrode and the lead provided on the other surface of the piezoelectric element.

9. The piezoelectric diaphragm according to claim 7 , wherein the adhesive inside the opening is an adhesive different from the conductive adhesive.

10. 9. The piezoelectric diaphragm according to claim 1, wherein the electrode provided on the other surface of the piezoelectric element and the lead are connected by soldering.

11. A diaphragm pump comprising: a piezoelectric vibration plate according to any one of claims 1, 2, 3, 7, and 8; a case having a recess; and a diaphragm bonded to the metal plate of the piezoelectric vibration plate and positioned so as to close the recess of the case.

12. A liquid ejection device comprising: a liquid ejection head that ejects liquid from an ejection port; and the diaphragm pump according to claim 11 that supplies liquid to the liquid ejection head.

13. A method for manufacturing a piezoelectric diaphragm including a piezoelectric element and a metal plate on which the piezoelectric element is laminated, and an electrode is provided on each of both surfaces of the piezoelectric element, a step of adhering a partial region of the electrode provided on one surface of the piezoelectric element to the metal plate with a heat-resistant adhesive, and adhering at least a part of a portion other than the partial region to the metal plate with a conductive adhesive; and connecting a lead to the electrode on the other surface of the piezoelectric element at a position that overlaps with the region in a plan view.

14. A method for manufacturing a piezoelectric diaphragm including a piezoelectric element and a metal plate on which the piezoelectric element is laminated, and an electrode is provided on each of both surfaces of the piezoelectric element, An opening is provided in a part of the metal plate, a step of adhering at least a portion of the electrode provided on one surface of the piezoelectric element, other than a region facing the opening in a plan view, to the metal plate using a conductive adhesive; connecting a lead to a part of a region of the electrode provided on the other surface of the piezoelectric element that faces the opening in a plan view; a step of injecting an adhesive into the opening after the step of connecting the lead, and using the adhesive to adhere an area of ​​the electrode provided on one side of the piezoelectric element that faces the opening in a planar view to the metal plate.

15. 15. The method for manufacturing a piezoelectric diaphragm according to claim 14, wherein the metal plate has a rib inside the opening in a plan view, and the step of connecting the lead is performed in a state where the piezoelectric element is supported from the one surface side by the rib.

16. The method for manufacturing a piezoelectric diaphragm according to claim 14 , wherein the step of connecting the leads is performed in a state where the piezoelectric element is supported from the one surface side by a support jig that passes through the opening.

17. The method for manufacturing a piezoelectric diaphragm according to claim 13 , wherein the step of connecting the leads comprises soldering the leads to the electrodes.

18. a step of adhering a diaphragm to the metal plate of the piezoelectric diaphragm manufactured by the method for manufacturing a piezoelectric diaphragm according to claim 13; and attaching the piezoelectric diaphragm to a case having a recess so that the diaphragm closes the recess.

19. a step of adhering a diaphragm to the metal plate of the piezoelectric diaphragm manufactured by the method for manufacturing a piezoelectric diaphragm according to any one of claims 14 to 16; and attaching the piezoelectric diaphragm to a case having a recess so that the diaphragm closes the recess.

20. 20. The method for manufacturing a diaphragm pump according to claim 19, wherein the adhesive is injected into the opening and applied to a surface of the metal plate opposite to the surface bonded to the one surface of the piezoelectric element, and the diaphragm is bonded to the metal plate by the adhesive.

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