JP7155656B2 - Piezoelectric device, liquid ejecting head, and liquid ejecting apparatus - Google Patents

Description

The present invention relates to a piezoelectric device, a liquid ejecting head having the piezoelectric device, and a liquid ejecting apparatus including the liquid ejecting head.

2. Description of the Related Art Conventionally, there has been known a liquid ejecting head that ejects liquid droplets from a nozzle that communicates with a pressure generating chamber by deforming a piezoelectric element to generate pressure fluctuations in the liquid in the pressure generating chamber. A representative example is an ink jet recording head that ejects ink droplets as liquid droplets.

An ink jet recording head includes, for example, a piezoelectric element via a diaphragm on one side of a flow path forming substrate provided with pressure generating chambers communicating with nozzle openings, and the diaphragm is deformed by driving the piezoelectric element. Ink droplets are ejected from the nozzles by causing pressure changes in the pressure generating chambers.

Here, the piezoelectric element is composed of a first electrode, a piezoelectric layer, and a second electrode provided on a diaphragm containing zirconium oxide as the uppermost layer (see, for example, Patent Document 1). Further, in such a piezoelectric element, an active portion sandwiched between the first electrode and the second electrode and serving as a substantial driving portion is provided in each region of the vibration plate facing the pressure generating chamber. On both sides of the active portion in the region facing the pressure generating chamber, there is a diaphragm or a region where the diaphragm and the non-active portion of the piezoelectric element are laminated, and is called an arm portion. Furthermore, in such a piezoelectric element, by providing recesses opening on the side opposite to the substrate in regions corresponding to the arm portions of the piezoelectric layer, the displacement characteristics of the piezoelectric element are improved, that is, a large displacement is achieved at a low voltage. be able to.

A piezoelectric element provided with a moisture barrier layer for protecting the piezoelectric layer from moisture has also been proposed (see, for example, Patent Document 2).

JP 2010-228268 A JP 2008-066623 A

However, by providing a recess in the piezoelectric layer, the diaphragm is exposed or becomes closer to the outside atmosphere, so the zirconium oxide of the diaphragm reacts with moisture in a high-humidity environment, changing the characteristics of the diaphragm. There is a problem that

Also, although a configuration is disclosed in which the inside of the recess, particularly the bottom surface of the recess, is covered with the second electrode, moisture permeates the second electrode, and the moisture permeating the second electrode reacts with zirconium oxide of the diaphragm. As a result, there is a problem that the characteristics of the diaphragm change.

In particular, in an ink jet recording head having a structure in which the second electrode is provided in common over a plurality of active portions, as in Patent Document 1, the film thickness of the second electrode becomes thinner as the density of the active portion increases. As a result, moisture easily permeates the second electrode, so that the characteristics of the diaphragm tend to change.

In Patent Document 2, although the moisture barrier layer is provided on the piezoelectric element, the provision of the moisture barrier layer on the active region of the piezoelectric element reduces the amount of displacement of the piezoelectric element. be.

It should be noted that such problems are not limited to liquid jet heads represented by ink jet recording heads, but also exist in other piezoelectric devices.

In view of such circumstances, the present invention provides a piezoelectric device, a liquid ejecting head, and a liquid ejecting apparatus that suppress changes in the characteristics of the diaphragm due to moisture without inhibiting deformation of the piezoelectric element. aim.

A mode of the present invention for solving the above problem is a substrate in which a plurality of first recesses are formed, and a vibration plate provided on one surface side of the substrate, wherein the uppermost layer on the side opposite to the substrate is oxidized. A vibration plate having a zirconium oxide layer containing zirconium, a first electrode provided on one surface side of the substrate via the vibration plate, a piezoelectric layer provided on the first electrode, and on the piezoelectric layer and a piezoelectric element having a second electrode provided in the piezoelectric element, and the piezoelectric element includes an active portion sandwiched between the first electrode and the second electrode of the piezoelectric layer for each of the first recesses. The first electrode constitutes an individual electrode independently provided in each of the active portions, and the second electrode is provided in common to a plurality of the active portions The piezoelectric layer is provided with a second recess that is provided outside the active portion and opens on the side opposite to the substrate, and the substrate and the piezoelectric element are laminated together. A first moisture barrier layer formed of a material other than the zirconium oxide is formed in a region on the opposite side of the diaphragm from the substrate in the direction and overlapping the bottom surface of the second recess, and the The piezoelectric device is characterized in that the first moisture barrier layer is not formed in part of the region overlapping the active portion in the stacking direction.

Further, according to another aspect of the present invention, there is provided a liquid jet head including the piezoelectric device described above.

According to another aspect of the invention, there is provided a liquid ejecting apparatus including the liquid ejecting head described above.

1 is an exploded perspective view of a print head according to Embodiment 1 of the present invention; FIG. 1 is a plan view of a channel-forming substrate according to Embodiment 1 of the present invention; FIG. 1 is a cross-sectional view of a recording head according to Embodiment 1 of the present invention; FIG. 2 is an enlarged cross-sectional view of a main part of the print head according to Embodiment 1 of the present invention; FIG. 2 is an enlarged cross-sectional view of a main part of the print head according to Embodiment 1 of the present invention; FIG. FIG. 8 is an enlarged cross-sectional view of a main part of a print head according to Embodiment 2 of the present invention; FIG. 8 is an enlarged cross-sectional view of a main part of a print head according to Embodiment 3 of the present invention; FIG. 8 is an enlarged cross-sectional view of a main part of a print head according to Embodiment 3 of the present invention; FIG. 11 is an enlarged cross-sectional view of a main part of a print head according to Embodiment 4 of the present invention; FIG. 11 is an enlarged cross-sectional view of a main part of a print head according to Embodiment 5 of the present invention; FIG. 11 is an enlarged cross-sectional view of a main part of a print head according to Embodiment 6 of the present invention; 1 is a schematic diagram of a recording apparatus according to an embodiment of the invention; FIG.

The present invention will be described in detail below based on embodiments.
(Embodiment 1)
FIG. 1 is an exploded perspective view of an ink jet recording head which is a liquid jet head according to Embodiment 1 of the present invention, FIG. 2 is a plan view of a flow path forming substrate of the recording head, and FIG. 2, FIG. 4 is an enlarged view of the main part of FIG. 3, and FIG. 5 is a BB' line cross-sectional view of FIG.

As shown in the figure, the flow path forming substrate 10, which is a substrate constituting the ink jet recording head 1 (hereinafter also simply referred to as the recording head 1) of this embodiment, is made of stainless steel, metal such as Ni, ZrO ₂ or Al ₂ Ceramic materials typified by O3 _, glass ceramic materials, and oxides such as MgO and _LaAlO3 can be used. In this embodiment, the channel forming substrate 10 is made of a silicon single crystal substrate. A plurality of nozzles 21 for ejecting ink from pressure generating chambers 12, which are first concave portions partitioned by a plurality of partition walls 11, are arranged side by side on the flow path forming substrate 10 by anisotropic etching from one surface side. are arranged side by side along the direction of Hereinafter, this direction will be referred to as the side-by-side direction of the pressure generating chambers 12 or the first direction X. As shown in FIG. Further, the flow path forming substrate 10 is provided with a plurality of rows, two rows in the present embodiment, in which the pressure generating chambers 12 are arranged side by side in the first direction X. As shown in FIG. The direction in which a plurality of rows of the pressure generating chambers 12 are arranged will be referred to as a second direction Y hereinafter. In this embodiment, the portion between the pressure generating chambers 12 arranged side by side in the first direction X of the flow path forming substrate 10 is called a partition 11 . The partition 11 is formed along the second direction Y. As shown in FIG. That is, the partition walls 11 are portions of the flow path forming substrate 10 overlapping the pressure generating chambers 12 in the second direction Y. As shown in FIG. Further, a direction orthogonal to both the first direction X and the second direction Y is called a third direction Z. Specifically, the case member 40 side and the nozzle plate 20 side, which will be described later, are called the Z1 side and the Z2 side, respectively. Although the first direction X, the second direction Y, and the third direction Z are directions orthogonal to each other, the directions are not particularly limited to this, and may be directions that intersect at an angle other than orthogonal. .

A communication plate 15 and a nozzle plate 20 are sequentially laminated on the Z2 side, which is one surface side of the flow path forming substrate 10 .

The communication plate 15 is provided with a nozzle communication passage 16 that communicates the pressure generating chamber 12 and the nozzle 21, as shown in FIG. The communication plate 15 has an area larger than that of the flow path forming substrate 10 , and the nozzle plate 20 has an area smaller than that of the flow path forming substrate 10 . By providing the communication plate 15 in this way, the nozzles 21 of the nozzle plate 20 and the pressure generating chambers 12 can be separated from each other. It becomes less susceptible to thickening due to evaporation. In addition, since the nozzle plate 20 only needs to cover the opening of the nozzle communication passage 16 that communicates the pressure generating chamber 12 and the nozzle 21, the area of the nozzle plate 20 can be made relatively small, and the cost can be reduced. can be done. In this embodiment, the surface from which the nozzles 21 of the nozzle plate 20 are opened and ink droplets are ejected is referred to as a liquid ejection surface 20a.

Further, the communication plate 15 is provided with a first manifold portion 17 and a second manifold portion 18 that constitute a part of the manifold 100 .

The first manifold portion 17 is provided so as to penetrate the communication plate 15 in the third direction Z. As shown in FIG.
The second manifold portion 18 does not pass through the communication plate 15 in the third direction Z, but is provided to open the communication plate 15 toward the nozzle plate 20 .

In the communication plate 15 , a supply communication passage 19 communicating with one end of the pressure generation chamber 12 in the second direction Y is provided independently for each of the pressure generation chambers 12 . The supply communication passage 19 communicates the second manifold portion 18 with the pressure generating chamber 12 to supply the ink in the manifold 100 to the pressure generating chamber 12 .

As such a communication plate 15, stainless steel, metal such as nickel (Ni), ceramics such as zirconium (Zr), or the like can be used. It should be noted that the communication plate 15 is preferably made of a material having a coefficient of linear expansion similar to that of the flow path forming substrate 10 . That is, when a material having a coefficient of linear expansion that is significantly different from that of the channel forming substrate 10 is used for the communicating plate 15, the difference in coefficient of linear expansion between the channel forming substrate 10 and the communicating plate 15 causes warpage due to heating or cooling. occurs. In the present embodiment, by using the same material as the channel forming substrate 10, that is, a silicon single crystal substrate, for the communication plate 15, it is possible to suppress the occurrence of thermal warping, thermal cracking, peeling, and the like.

The nozzle plate 20 is formed with nozzles 21 communicating with the respective pressure generating chambers 12 via nozzle communication passages 16 . That is, the nozzles 21 that eject the same type of liquid (ink) are arranged in a first direction X, and the rows of the nozzles 21 arranged in the first direction X are arranged in a row in the second direction Y. Two rows are formed.

As such a nozzle plate 20, for example, a metal such as stainless steel (SUS), an organic material such as polyimide resin, a silicon single crystal substrate, or the like can be used. By using a silicon single crystal substrate as the nozzle plate 20, the linear expansion coefficients of the nozzle plate 20 and the communication plate 15 are made equal to suppress the occurrence of warpage due to heating and cooling, cracking, peeling, etc. due to heat. can do.

On the other hand, a vibration plate 50 is formed on the Z1 side, which is the other side of the flow path forming substrate 10 . The vibrating plate 50 has a zirconium oxide layer 52 containing zirconium oxide (ZrO _x ) on the uppermost layer on the side opposite to the flow path forming substrate 10 . In this embodiment, the vibration plate 50 includes an elastic film 51 containing silicon oxide (SiO _x ) provided on the side of the flow path forming substrate 10 , and the flow path forming substrate 10 on the elastic film 51 , that is, on the elastic film 51 . and a zirconium oxide layer 52 comprising zirconium oxide (ZrO _x ) provided on the opposite side. In this embodiment, an elastic film 51 containing silicon dioxide (SiO ₂ ) and a zirconium oxide layer 52 containing zirconium oxide (ZrO ₂ ) are used. Here, the zirconium oxide layer 52 may contain other materials as long as it contains zirconium oxide as a main component. In addition, that the main component of the zirconium oxide layer 52 is zirconium oxide means that the zirconium oxide contained in the zirconium oxide layer 52 is 50% by mass or more. Further, in this embodiment, the elastic film 51 containing silicon oxide is provided as the diaphragm 50, but the material of the elastic film 51 is not limited to silicon oxide, and may be titanium oxide or the like. Alternatively, the diaphragm 50 may not be provided with the elastic film 51 . That is, the diaphragm 50 may be composed only of the zirconium oxide layer 52 . Zirconium Oxide Layer 52 By using the zirconium oxide layer 52 containing zirconium oxide in the diaphragm 50 as described above, the rigidity and toughness of the diaphragm 50 can be ensured. In addition, by using the zirconium oxide layer 52 containing zirconium oxide as the uppermost layer on the opposite side of the flow path forming substrate 10 of the vibration plate 50, lead (Pb) and bismuth ( Components such as Bi) can be suppressed from diffusing below the zirconium oxide layer 52 , that is, into the elastic film 51 and the channel-forming substrate 10 . That is, by providing the zirconium oxide layer 52 made of zirconium oxide as the uppermost layer of the vibration plate 50, the components contained in the piezoelectric layer 70 are suppressed from diffusing into the elastic film 51 and the flow path forming substrate 10, thereby increasing the elasticity. It is possible to suppress problems such as reduction in rigidity due to diffusion of the components of the piezoelectric layer 70 into the film 51, the flow path forming substrate 10, and the like.

The liquid flow paths such as the pressure generating chambers 12 are formed by anisotropically etching the flow path forming substrate 10 from one side (the side to which the nozzle plate 20 is bonded). is defined by an elastic membrane 51 . That is, by providing the elastic film 51 containing silicon oxide on the flow path forming substrate 10 side of the diaphragm 50 , the flow path forming substrate 10 is subjected to an anisotropic treatment using an alkaline solution such as KOH from the side opposite to the diaphragm 50 . The elastic film 51 can be used as an etching stop layer during the etching. Therefore, the pressure generating chambers 12 can be formed in the passage forming substrate 10 with high density and high accuracy by anisotropic etching, and variations in the thickness of the vibration plate 50 can be suppressed. Of course, the method of forming the pressure generating chamber 12 is not limited to anisotropic etching, and dry etching or the like may be used.

As shown in FIGS. 4 and 5, a piezoelectric actuator 300 including a first electrode 60, a piezoelectric layer 70, and a second electrode 80 is formed on the vibration plate 50 of the flow path forming substrate 10. ing. In this embodiment, the piezoelectric actuator 300 serves as pressure generating means for causing pressure change in the ink in the pressure generating chamber 12 . Here, the piezoelectric actuator 300 is also called a piezoelectric element 300 and refers to a portion including the first electrode 60 , the piezoelectric layer 70 and the second electrode 80 . A portion where piezoelectric strain occurs in the piezoelectric layer 70 when a voltage is applied between the first electrode 60 and the second electrode 80 is called an active portion 310 . That is, the active portion 310 is a portion of the piezoelectric layer 70 sandwiched in the third direction Z between the first electrode 60 and the second electrode 80 . In this embodiment, an active portion 310 is formed for each pressure generating chamber 12 that is the first concave portion. In this embodiment, the first electrode 60 constitutes an individual electrode provided independently for each of the active portions 310 , and the second electrode 80 is a common electrode provided commonly to the plurality of active portions 310 . make up the electrodes.

Here, the first electrode 60 constituting the piezoelectric actuator 300 of the present embodiment is separated for each pressure generating chamber 12, and an independent individual electrode is provided for each active portion 310, which is a substantial driving portion of the piezoelectric actuator 300. Configure. The first electrode 60 is formed with a width narrower than the width of the pressure generating chamber 12 in the first direction X, which is the direction in which the active portions 310 are arranged side by side. That is, in the first direction X of the pressure generating chamber 12 , the end portion of the first electrode 60 is located inside the region facing the pressure generating chamber 12 . Although the details will be described later, since the second electrode 80 is provided wider than the first electrode 60 in the first direction X, the width of the active portion 310 of the present embodiment in the first direction X is defined by the first electrode 60 .

It should be noted that the material of the first electrode 60 must be a material that does not oxidize when the piezoelectric layer 70, which will be described later, is formed and that can maintain conductivity. ), or conductive oxides typified by lanthanum nickel oxide (LNO) are preferably used.

Further, as the first electrode 60, an adhesion layer for ensuring adhesion may be used between the aforementioned conductive material and the diaphragm 50. FIG. In this embodiment, titanium is used as the adhesion layer, although not shown. Zirconium, titanium, titanium oxide, or the like can be used as the adhesion layer. That is, in the present embodiment, the first electrode 60 is formed of an adhesion layer made of titanium and at least one conductive layer selected from the conductive materials described above.

As shown in FIG. 4, the piezoelectric layer 70 is continuously provided in the first direction X so that the second direction Y has a predetermined width.

In the second direction Y of the pressure generating chamber 12 , the end of the piezoelectric layer 70 on the side of the supply communication path 19 is located outside the end of the first electrode 60 . That is, the end of the first electrode 60 is covered with the piezoelectric layer 70 . In addition, in the second direction Y, the end of the piezoelectric layer 70 on the nozzle 21 side is located inside (on the pressure generating chamber 12 side) the end of the first electrode 60 . The end on the nozzle 21 side is not covered with the piezoelectric layer 70 .

The piezoelectric layer 70 is made of an oxide piezoelectric material having a polarized structure formed on the first electrode 60, and can be made of, for example, a perovskite-type oxide represented by the general formula ABO ₃ , and contains lead. Piezoelectric materials, lead-free piezoelectric materials that do not contain lead, and the like can be used. The piezoelectric layer 70 is formed by, for example, a liquid phase method such as a sol-gel method or a MOD (Metal-Organic Decomposition) method, or a PVD (Physical Vapor Deposition) method (vapor phase method) such as a sputtering method or a laser ablation method. can be formed with

As shown in FIG. 5, such a piezoelectric layer 70 is formed with a second concave portion 71 that opens on the side opposite to the flow path forming substrate 10 outside the active portion 310 . That is, since the active portion 310 of the present embodiment is defined by the first electrode 60 in the first direction X, the second concave portion 71 is provided outside the first electrode 60 in the first direction X. It is Also, since the active portions 310 are arranged side by side in the first direction X, the second recesses 71 are arranged between the active portions 310 adjacent to each other in the first direction X. As shown in FIG.

Further, in the present embodiment, the second concave portion 71 is provided so as to penetrate the piezoelectric layer 70 in the third direction Z, which is the stacking direction. That is, the second recess 71 is formed with a depth reaching the vibration plate 50 , the piezoelectric layer 70 is not formed on the bottom surface 711 of the second recess 71 , and the bottom surface 711 of the second recess 71 vibrates. A plate 50 is exposed.

Here, the second recess 71 and the pressure generating chamber 12, which is the first recess, are positioned at least partially overlapping each other in the third direction Z, which is the lamination direction of the flow path forming substrate 10 and the piezoelectric element 300. are placed. Moreover, it is preferable that the width of the second concave portion 71 in the first direction X is substantially the same as or wider than the width of each partition wall 11 in the first direction X. Here, the width of the second recess 71 in the first direction X is the width of the pressure generating chamber 12 closest to the first recess in the third direction Z, that is, the width of the bottom surface side of the second recess 71. That is. The width of the pressure generating chamber 12, which is the first recess, in the first direction X is the width closest to the second recess 71 in the third direction Z, that is, the width of the bottom surface.

Incidentally, the fact that the pressure generating chamber 12 and the second recessed portion 71, which are the first recessed portions, are arranged at a position where at least a part thereof overlaps in the third direction Z means that the widths of the pressure generating chamber 12 and the second recessed portion 71 are It also includes those whose defined bottom sides do not overlap each other. That is, for example, if the side surface of the pressure generating chamber 12 and the side surface of the second recessed portion 71 are provided at an angle, even if these bottom surfaces do not overlap each other, the opening sides thereof are partially overlapped. Arrangement is also possible.

By providing the second concave portion 71 in the piezoelectric layer 70 in this manner, the rigidity of the arms between the diaphragm 50 and the wall surface of the pressure generating chamber 12 of the piezoelectric element 300 and the active portion 310 can be reduced. , the piezoelectric element 300 can be satisfactorily displaced.

The width of the second recess 71 in the first direction X should be substantially the same as or wider than the width of each partition wall 11 in the first direction X. By arranging at a position where at least a part overlaps in the third direction Z on the bottom surface side that defines the width in the first direction X of the , and the displacement characteristics of the piezoelectric element 300 can be improved, that is, a high displacement can be obtained at a low voltage.

The second electrode 80 is provided on the opposite side of the piezoelectric layer 70 to the first electrode 60 and constitutes a common electrode common to the plurality of active portions 310 . In addition, the second electrode 80 is provided continuously across the inner surface of the second recess 71 , that is, the bottom surface of the second recess 71 on the side of the flow path forming substrate 10 and the side surface on the side of the piezoelectric layer 70 . . Note that the second electrode 80 does not have to be provided on the inner surface of the second concave portion 71 .

Such a second electrode 80 is desirably made of a material that can satisfactorily form the interface of the piezoelectric layer 70 and exhibit electrical conductivity and piezoelectric properties. Au) and other noble metal materials and conductive oxides typified by lanthanum nickel oxide (LNO) are preferably used. Also, the second electrode 80 may be a laminate of a plurality of materials. In this embodiment, a laminated electrode of iridium and titanium (iridium is in contact with the piezoelectric layer 70) is used. The second electrode 80 is formed by a sputtering method, a PVD (Physical Vapor Deposition) method (gas phase method) such as a laser ablation method, a sol-gel method, a MOD (Metal-Organic Decomposition) method, a liquid phase method such as a plating method. can be formed by Further, by performing heat treatment after forming the second electrode 80, the characteristics of the piezoelectric layer 70 can be improved.

In addition, in the third direction Z, a material different from that of the second electrode 80 is formed in a region of the vibration plate 50 opposite to the flow path forming substrate 10 and overlapping with the bottom surface 711 of the second recess 71 of the piezoelectric layer 70 . A first moisture barrier layer 200 is provided. Here, that the first moisture barrier layer 200 is provided on the opposite side of the diaphragm 50 to the flow path forming substrate 10 in the third direction Z means that the first moisture barrier layer 200 is provided in the third direction Z. It means that it is provided on the Z1 side of the diaphragm 50 in the Z direction. In this embodiment, the first moisture barrier layer 200 is provided between the diaphragm 50 and the second electrode 80 . That is, since the second recessed portion 71 is provided so as to penetrate the piezoelectric layer 70 in the third direction Z, on the bottom surface 711 of the second recessed portion 71 , the vibration plate 50 and the first , the moisture barrier layer 200 and the second electrode 80 are laminated in this order.

The bottom surface 711 of the second recess 71 is the inner surface of the second recess 71 closest to the flow path forming substrate 10 in the third direction Z. As shown in FIG. Further, the fact that the first moisture barrier layer 200 is provided in a region overlapping with the bottom surface 711 of the second concave portion 71 means that when viewed from the third direction Z, the first moisture barrier layer 200 It means that the entire surface of the bottom surface 711 of the recess 71 is overlapped. Further, the first moisture barrier layer 200 provided in a region overlapping the bottom surface 711 of the second recess 71 means that the first moisture barrier layer 200 overlaps at least the bottom surface 711 of the second recess 71 . To tell. That is, the first moisture barrier layer 200 extends from the area overlapping the bottom surface 711 of the second recess 71 to the area outside thereof. In this embodiment, the first moisture barrier layer 200 extends from the region overlapping the bottom surface 711 of the second recess 71 toward the active portion 310 side. The portion of the first moisture barrier layer 200 extending from the bottom surface 711 of the second recess 71 toward the active portion 310 is between the piezoelectric layer 70 and the second electrode 80 in this embodiment. is provided. That is, the portion of the first moisture barrier layer 200 extending from the bottom surface 711 of the second recess 71 toward the active portion 310 is provided on the side surface 712 of the second recess 71 . In addition, the portion of the first moisture barrier layer 200 extending from the bottom surface 711 of the second recess 71 toward the active portion 310 extends until it reaches the surface of the piezoelectric layer 70 on the Z1 side. . The first moisture barrier layer 200 is provided continuously over the inner surface of the second recess 71 and the peripheral edge of the opening of the second recess 71 of the piezoelectric layer 70 .

Also, the first moisture barrier layer 200 is not provided in part of the region overlapping the active portion 310 in the third direction Z. FIG. That is, the first moisture barrier layer 200 is not provided in all or part of the region overlapping the active portion 310 in the third direction Z. FIG. In this embodiment, the first moisture barrier layer 200 does not extend to the region overlapping the active portion 310 in the third direction Z, and is not provided in the entire region overlapping the active portion 310 . For this reason, the end of the first moisture barrier layer 200 is located outside the active portion 310 on the Z1 side surface of the piezoelectric layer 70 in the cross section in the first direction X. As shown in FIG. That is, as shown in FIG. 2, the first moisture barrier layer 200 has an opening 201 that is larger than the active portion 310 . That is, the opening 201 of the first moisture barrier layer 200 is provided in the third direction Z with a size and position that includes the active portion 310 .

In this way, the first moisture barrier layer 200 is extended to the surface of the piezoelectric layer 70 where the second concave portion 71 opens, and an opening 201 that opens in the Z1 side surface of the piezoelectric layer 70 is provided. Thus, when forming and patterning the first moisture barrier layer 200, the first moisture barrier layer 200 can be patterned on the Z1 side plane of the piezoelectric layer 70, thereby improving the patterning accuracy. As a result, variations in the displacement characteristics of the piezoelectric element 300 due to the positional deviation of the opening 201 can be suppressed. Of course, the first moisture barrier layer 200 only needs to be provided in the region overlapping the bottom surface 711 of the second recess 71 , and the first moisture barrier layer 200 is provided only on the bottom surface 711 of the second recess 71 . Also, the first moisture barrier layer 200 extends halfway between the bottom surface of the second recess 71 and the side surface 712 on the side of the bottom surface 711 , that is, the opening 201 opens halfway along the side surface 712 of the second recess 71 . You may do so.

When a conductive material is used as the material of the first moisture barrier layer 200, the portion of the first electrode 60, which is an individual electrode, formed outside the piezoelectric layer 70 and the It is preferable to provide it in a region that does not overlap in the third direction Z with the portion where the individual wiring 91 connected to the first electrode 60 is formed. This can prevent the first electrodes 60 from being short-circuited by the first moisture barrier layer 200 . Further, when a material having insulating properties is used as the material of the first moisture barrier layer 200, the first moisture barrier layer 200 may be formed on the portion of the first electrode 60 outside the piezoelectric layer 70 or , may also be provided in a region overlapping with the individual wiring 91 in the third direction Z. FIG.

As a material for such a first moisture barrier layer 200, any material other than zirconium oxide can be used, and an inorganic material, an organic material, or the like can be used. Also, the first moisture barrier layer 200 may be a material having conductivity or a material having insulating properties. Incidentally, in the case of a conductive material such as a metal, the electrical resistance of the second electrode 80 is reduced so that the first direction X, which is the direction in which the active portions 310 of the second electrode 80 are arranged side by side, is used. By suppressing the voltage drop at , it is possible to suppress variations in the displacement of the active portion 310 .

Inorganic materials that can be used as the first moisture barrier layer 200 include at least one selected from metals, oxide films, and nitride films. That is, the first moisture barrier layer 200 may use a single inorganic material, or may be a laminate of different materials. As the inorganic material for the first moisture barrier layer 200, it is particularly preferable to use an inorganic amorphous material, that is, an amorphous oxide film and nitride film. Examples of such an amorphous oxide film include aluminum oxide (AlO _x ) such as alumina (Al ₂ O ₃ ). By using an amorphous oxide film and a nitride film as the first moisture barrier layer 200 in this way, it is possible to reliably suppress the permeation of moisture, improve the mechanical strength, and prevent damage such as cracks. can be suppressed.

Table 1 below shows the water vapor permeability of silicon oxide (SiO ₂ ) and aluminum oxide (Al ₂ O ₃ ), which are typical examples of oxide films.

As shown in Table 1, between silicon oxide (SiO ₂ ) and aluminum oxide (Al ₂ O ₃ ), aluminum oxide (Al ₂ O ₃ ) has better moisture barrier properties than silicon oxide (SiO ₂ ). there is Therefore, when an inorganic material is used for the first moisture barrier layer 200 , aluminum oxide (Al ₂ O ₃ ) is used to suppress moisture permeation through the first moisture barrier layer 200 , thereby forming the zirconium oxide layer 52 . can be protected from moisture.

Further, when a metal is used as the first moisture barrier layer 200, it is possible to suppress the formation of pinholes and the like by performing an annealing treatment after film formation, thereby improving moisture barrier properties. can be done.

Organic materials that can be used as the first moisture barrier layer 200 include, for example, at least one selected from epoxy resins, polyimide resins, silicon-based resins, and fluorine-based resins. Also, the first moisture barrier layer 200 may be formed of either one of an inorganic material and an organic material, or may be a laminate of both.

By providing the first moisture barrier layer 200 overlapping at least the bottom surface 711 of the second recess 71 in this way, the zirconium oxide layer 52 of the diaphragm 50 is arranged at a position close to the external atmosphere by the second recess 71 . However, the first moisture barrier layer 200 can protect the zirconium oxide layer 52 from moisture contained in the atmosphere. Therefore, by providing the first moisture barrier layer 200, the zirconium oxide layer 52 and moisture are prevented from reacting with each other, thereby suppressing a change in the properties of the zirconium oxide layer 52, thereby suppressing breakage of the diaphragm 50. be able to. Incidentally, if the first moisture barrier layer 200 is not provided, the vibration plate 50 breaks in a high-humidity environment or the like. This is because when the zirconium oxide layer 52 reacts with moisture, the characteristics of the zirconium oxide layer 52 are changed, and the zirconium oxide layer 52 and the second electrode 80 are peeled off. 50 alone, and the tensile stress due to the displacement of the active portion 310 is applied to the diaphragm 50 . Another factor is that the toughness of the zirconium oxide layer 52 decreases due to reaction between the zirconium oxide layer 52 and moisture. Therefore, in the present embodiment, by providing the first moisture barrier layer 200, it is possible to suppress the reaction between the zirconium oxide layer 52 and moisture, which may cause breakage of the vibration plate 50. Breakage of diaphragm 50 can be suppressed.

In addition, in the present embodiment, the first moisture barrier layer 200 is not provided in at least part of the region overlapping the active portion 310 in the third direction Z, so that the first moisture barrier layer 200 activates the It is possible to prevent the portion 310 from being restrained, thereby suppressing a decrease in the amount of displacement of the active portion 310 .

In this embodiment, the flow path forming substrate 10, which is a substrate on which the pressure generating chambers 12 that are the first recesses are formed, the vibration plate 50, the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are The piezoelectric element 300 provided with the second concave portion 71 is collectively referred to as a piezoelectric device.

Further, as shown in FIG. 2 , individual wiring 91 as a lead wiring is drawn out from the first electrode 60 of the piezoelectric actuator 300 . A common wiring 92 that is a lead wiring is drawn from the second electrode 80 . Furthermore, a flexible cable 120 is connected to the extended ends of the individual wires 91 and the common wires 92 opposite to the ends connected to the piezoelectric actuator 300 . The flexible cable 120 is a wiring board having flexibility, and in this embodiment, a driving circuit 121, which is a driving element, is mounted thereon.

In addition, in this embodiment, an insulating material is used as the first moisture barrier layer 200 . 2 and 4, the first moisture barrier layer 200 of the present embodiment is continuous over the zirconium oxide layer 52 outside the piezoelectric layer 70 in the second direction Y. are provided. Also, the first moisture barrier layer 200 extends in the second direction Y from above the zirconium oxide layer 52 toward the active portion 310 of the first moisture barrier layer 200 . The extended portion covers the side surface of the piezoelectric layer 70 and extends to reach the surface of the piezoelectric layer 70 on the Z1 side. The individual wiring 91 of the individual wiring 91 and the first electrode 60 are electrically connected through a contact hole 202 provided in the first moisture barrier layer 200 .

By thus providing the first moisture barrier layer 200 so as to cover the exposed zirconium oxide layer 52 on both sides of the piezoelectric actuator 300 in the second direction Y, both sides of the piezoelectric actuator 300 in the second direction Y zirconium oxide layer 52 can be protected from moisture. Therefore, even in the second direction Y, the reaction between the zirconium oxide layer 52 and moisture, which causes breakage of the diaphragm 50, can be suppressed, and breakage of the diaphragm 50 can be suppressed in a high-humidity environment or the like. can.

In addition, by providing the first moisture barrier layer 200 between the individual wiring 91 and the first electrode 60 at the end of the piezoelectric actuator 300 on the side of the individual wiring 91 in the second direction Y, moisture is prevented from and the first electrode 60 to prevent it from penetrating into the zirconium oxide layer 52, thereby protecting the zirconium oxide layer 52 from moisture.

Furthermore, by covering the side surface of the piezoelectric layer 70 with the first moisture barrier layer 200 in the second direction Y, the portion of the piezoelectric layer 70 exposed to the outside is reduced and the piezoelectric layer 70 is protected from moisture. can be protected from Therefore, deterioration of the piezoelectric layer 70 due to moisture and separation of the second electrode 80 and the piezoelectric layer 70 due to moisture can be suppressed.

It should be noted that the first moisture barrier layer 200 is not provided in part of the region overlapping the active portion 310 in the third direction Z, even in the second direction Y. That is, the first moisture barrier layer 200 extends over the active portion 310 on the one end side in the second direction Y on the side of the individual wiring 91, and on the other end side in the second direction Y , is provided outside the active portion 310 , that is, outside the first electrode 60 . The first moisture barrier layer 200 is provided with an opening 201 opening to the main portion of the active portion 310 . By providing the openings 201 in the first moisture barrier layer 200 in this manner, the first moisture barrier layer 200 suppresses the deformation of the piezoelectric actuator 300 and reduces the amount of displacement of the piezoelectric actuator 300 . can be suppressed.

A protective substrate 30 having approximately the same size as the flow path forming substrate 10 is bonded to the surface of the flow path forming substrate 10 on the Z1 side. The protection substrate 30 has a holding portion 31 that is a space for protecting the piezoelectric actuator 300 . Two holding portions 31 are formed side by side in the second direction Y between rows of the piezoelectric actuators 300 arranged in the first direction X. As shown in FIG. Further, the protective substrate 30 is provided with a through hole 32 penetrating in the third direction Z between two holding portions 31 arranged in the second direction Y. As shown in FIG. The end portions of the individual wiring 91 and the common wiring 92 drawn out from the electrodes of the piezoelectric actuator 300 are extended so as to be exposed in the through hole 32, and the individual wiring 91 and the common wiring 92 and the flexible cable 120 pass through. They are electrically connected within the holes 32 . The connection method between the individual wiring 91 and the common wiring 92 and the flexible cable 120 is not particularly limited. conductive adhesives (ACP, ACF), non-conductive adhesives (NCP, NCF), and the like.

As shown in FIG. 3 , a case member 40 is fixed on the protective substrate 30 to define a manifold 100 communicating with the plurality of pressure generating chambers 12 together with the flow path forming substrate 10 . The case member 40 has substantially the same shape as the communication plate 15 described above in a plan view, and is joined to the protection substrate 30 as well as to the communication plate 15 described above.

Such a case member 40 has a recess 41 with a depth that accommodates the flow path forming substrate 10 and the protection substrate 30 on the protection substrate 30 side. The concave portion 41 has an opening area larger than the surface of the protective substrate 30 joined to the flow path forming substrate 10 . The opening surface of the recess 41 on the side of the nozzle plate 20 is sealed by the communication plate 15 while the passage forming substrate 10 and the like are accommodated in the recess 41 . As a result, a third manifold portion 42 is defined by the case member 40 and the flow path forming substrate 10 at the outer peripheral portion of the flow path forming substrate 10 . The manifold of the present embodiment is formed by the first manifold portion 17 and the second manifold portion 18 provided on the communication plate 15 and the third manifold portion 42 defined by the case member 40 and the flow path forming substrate 10. 100 are configured. The manifold 100 is continuously provided in the first direction X, which is the direction in which the pressure generating chambers 12 are arranged side by side. are arranged side by side in the direction X.

A compliance substrate 45 is provided on the surface of the communication plate 15 on the Z2 side where the first manifold portion 17 and the second manifold portion 18 are opened. The compliance substrate 45 seals the openings of the first manifold portion 17 and the second manifold portion 18 on the side of the liquid ejection surface 20a. Such a compliance substrate 45 includes a sealing film 46 made of a flexible thin film and a fixed substrate 47 made of a hard material such as metal in this embodiment. A region of the fixed substrate 47 facing the manifold 100 is the fixed substrate opening 48 that is completely removed in the thickness direction. The compliance portion 49 is a sealed flexible portion.

The case member 40 is provided with an introduction passage 44 that communicates with the manifolds 100 to supply ink to each manifold 100 . Further, the case member 40 is provided with a connection port 43 that communicates with the through hole 32 of the protective substrate 30 and through which the flexible cable 120 is inserted.

In such a recording head 1 , when ejecting ink, the ink is taken in from the introduction path 44 and the inside of the flow path from the manifold 100 to the nozzles 21 is filled with ink. After that, according to the signal from the driving circuit 121, by applying a voltage to each active portion 310 corresponding to the pressure generating chamber 12, the active portion 310 and the diaphragm 50 are deformed. As a result, the pressure in the pressure generating chamber 12 is increased and ink droplets are ejected from the predetermined nozzles 21 .

As described above, in the present embodiment, the flow path forming substrate 10, which is a substrate in which the pressure generating chambers 12, which are a plurality of first recesses, are formed, and the vibration plate provided on one surface side of the flow path forming substrate 10. A vibrating plate 50 having a zirconium oxide layer 52 containing zirconium oxide as the uppermost layer on the side opposite to the flow path forming substrate 10 and a vibrating plate 50 provided on one side of the flow path forming substrate 10 via the vibrating plate 50 a piezoelectric element 300 having a first electrode 60 formed thereon, a piezoelectric layer 70 provided on the first electrode 60, and a second electrode 80 provided on the piezoelectric layer 70; , the active portion 310 sandwiched between the first electrode 60 and the second electrode 80 of the piezoelectric layer 70 is provided independently for each pressure generating chamber 12, and the first electrode 60 is provided in each of the active portions 310. Independently provided individual electrodes are configured, the second electrode 80 configures a common electrode provided commonly to the plurality of active portions 310 , and the piezoelectric layer 70 is provided outside the active portions 310 . A second concave portion 71 is provided and is opened on the side opposite to the flow path forming substrate. A first moisture barrier layer 200 made of a material other than zirconium oxide is formed in a region opposite to the path-forming substrate 10 and overlapping the bottom surface of the second recess 71 . 200 is not formed in part of the region overlapping the active portion 310 in the third direction Z. FIG.

Thus, by providing the second recess 71, the displacement characteristics of the piezoelectric element 300 can be improved. By providing the first moisture barrier layer 200, the zirconium oxide layer 52 can be prevented from reacting with moisture, and the diaphragm 50 can be protected from moisture. Therefore, it is possible to suppress destruction of the diaphragm 50 due to the zirconium oxide layer 52 reacting with moisture and changing the characteristics of the diaphragm 50 .

Further, by providing the first moisture barrier layer 200, it is possible to protect the diaphragm 50 from moisture permeating the second electrode 80. Therefore, the thickness of the second electrode 80 can be made relatively thin, and the active portion can be protected. 310 can be densely arranged.

Moreover, in the present embodiment, it is preferable that the plurality of active portions 310 are arranged side by side in the first direction X, and the second concave portions 71 are provided on both sides of the active portion 310 in the first direction X. FIG. According to this, the active portions 310 can be arranged in the first direction X with high density, and the amount of displacement in the third direction Z in the cross section of the active portions 310 in the first direction X can be improved. be able to.

In addition, in the third direction Z, which is the stacking direction, the second recess 71 and the pressure generating chamber 12, which is the first recess, are preferably arranged at positions at least partially overlapping each other. According to this, the rigidity of the arm portion between the wall surface of the channel forming substrate 10 and the active portion 310 can be reduced by the second concave portion 71, and the displacement characteristics of the active portion 310 can be improved.

Of course, in the third direction Z, the pressure generating chamber 12, which is the first recess, and the second recess 71 do not have to be arranged such that at least a portion of them overlap each other.

In addition, the first moisture barrier layer 200 provided in the region overlapping the bottom surface 711 of the second recess 71 in the third direction Z, which is the stacking direction, is provided between the vibration plate 50 and the second electrode 80. preferably. According to this, it is possible to suppress the intrusion of moisture from the interface between the first moisture barrier layer 200 and the second electrode 80, thereby suppressing the diaphragm 50 from reacting with the moisture and destroying the diaphragm 50. can be done.

Also, the first moisture barrier layer 200 preferably extends from the region overlapping the bottom surface 711 of the second concave portion 71 toward the active portion 310 in the third direction Z, which is the stacking direction. According to this, by extending the first moisture barrier layer 200, the diaphragm 50 closer to the active portion 310 than the bottom surface of the second recess 71 can be protected from moisture.

Moreover, it is preferable that the portion of the first moisture barrier layer 200 extending toward the active portion 310 is provided between the piezoelectric layer 70 and the second electrode 80 . According to this, even if moisture permeates the second electrode 80, the first moisture barrier layer 200 can protect the piezoelectric layer 70 and the vibration plate 50 below the second electrode 80. Separation at the interface between 70 and second electrode 80 can be suppressed.

Also, the first moisture barrier layer 200 is preferably made of metal. By forming the first moisture barrier layer 200 from a metal in this manner, the first moisture barrier layer 200 can be heat-treated and annealed at the same time as the piezoelectric layer 70 is fired. Therefore, formation of pinholes or the like in the first moisture barrier layer 200 can be suppressed, and moisture barrier properties can be improved.

Also, the first moisture barrier layer 200 is preferably an amorphous oxide film or nitride film. By forming the first moisture barrier layer 200 with an amorphous oxide film or nitride film in this way, it is possible to reliably suppress the permeation of moisture, improve the mechanical strength, and Also, the first moisture barrier layer 200 can be prevented from being damaged such as cracks.

The second recess 71 is provided so as to penetrate the piezoelectric layer 70 in the third direction Z, which is the stacking direction. It is preferable that the vibration plate 50, the first moisture barrier layer 200, and the second electrode 80 are laminated in this order. According to this configuration, the second concave portion 71 penetrates the piezoelectric layer 70 in the third direction Z, thereby reducing the rigidity of the arm portion and improving the displacement characteristic of the active portion 310, and at the same time, vibrating. Even if the second electrode 80 is provided on the plate 50 , the provision of the first moisture barrier layer 200 can protect the diaphragm 50 from moisture that has permeated the second electrode 80 .

Of course, the second concave portion 71 may be provided without penetrating the piezoelectric layer 70 in the third direction Z.

(Embodiment 2)
FIG. 6 is a cross-sectional view of a principal portion of an ink jet recording head, which is an example of a liquid jet head according to Embodiment 2 of the present invention, and is a cross-sectional view corresponding to line BB' of FIG. In addition, the same code|symbol is attached|subjected to the member similar to embodiment mentioned above, and the overlapping description is abbreviate|omitted.

As shown in FIG. 6, the piezoelectric element 300 of this embodiment is provided with a first moisture barrier layer 200 and a second moisture barrier layer 210 .

The second moisture barrier layer 210 is formed of a material different from that of the first moisture barrier layer 200 between the piezoelectric layer 70 of the active section 310 and the second electrode 80 .

As the material for the first moisture barrier layer 200, the same material as described above can be used.

A metal is used as the material for the second moisture barrier layer 210 . The metal, which is the material of the second moisture barrier layer 210, may be any material as long as it has conductivity, and includes metals and metal oxides. Examples of metals used for the second moisture barrier layer 210 include gold (Au), silver (Ag), platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru ) and osmium (Os). In addition, when a metal is used as the second moisture barrier layer 210, the formation of pinholes or the like can be suppressed by performing an annealing treatment after film formation, thereby improving moisture barrier properties. can be done.

By using a conductive material for the second moisture barrier layer 210 , a voltage can be applied to the active portion 310 of the piezoelectric layer 70 from the second electrode 80 via the second moisture barrier layer 210 . . In addition, by forming the first moisture barrier layer 200 and the second moisture barrier layer 210 from different materials, the first moisture barrier layer 200 can achieve moisture permeation without applying a voltage to the active portion 310 . A material with a low modulus can be used, the diaphragm 50 can be protected from moisture, and the second moisture barrier layer 210 can apply a voltage to the active portion 310 and Any material suitable for deformation can be used.

Also, by providing the second moisture barrier layer 210 , the piezoelectric layer 70 can be protected from moisture permeating the second electrode 80 even in the active portion 310 . Therefore, deterioration of the piezoelectric layer 70 due to moisture and separation of the second electrode 80 and the piezoelectric layer 70 due to moisture can be suppressed. In other words, the second electrode 80 and the second moisture barrier layer 210 can be firmly bonded by being made of metal, and the moisture permeating the second electrode 80 is unlikely to cause separation between the two. In addition, the second moisture barrier layer 210 makes it difficult for moisture that has permeated the second electrode 80 to permeate the piezoelectric layer 70 , so that the second moisture barrier layer 210 and the piezoelectric layer 70 are separated from each other by moisture. hard.

In addition, in the third direction Z, which is the lamination direction of the flow path forming substrate 10 and the piezoelectric element 300, the first moisture barrier layer 200 and the second moisture barrier layer 210 are arranged at positions at least partially overlapping each other. It is That is, in the present embodiment, the second moisture barrier layer 210 extends from the active portion 310 to the outside of the active portion 310, and the extended portion is the first moisture barrier layer 200 and the second moisture barrier layer 200. is arranged so as to overlap in the third direction Z with the moisture barrier layer 210 of .

In this way, by arranging the first moisture barrier layer 200 and the second moisture barrier layer 210 so that at least a part thereof overlaps in the third direction Z, moisture permeating through the second electrode 80 is transmitted to the diaphragm. Permeation to the 50 side can be reliably suppressed, and problems due to moisture on the diaphragm 50 can be suppressed.

As described above, in the present embodiment, between the piezoelectric layer 70 of the active section 310 and the second electrode 80, the second moisture barrier layer made of a material different from that of the first moisture barrier layer 200 is provided. A layer 210 is provided. By providing the second moisture barrier layer 210 in the active portion 310 in this manner, the piezoelectric layer 70 can be protected from moisture permeating the second electrode 80 also in the active portion 310 . Therefore, deterioration of the piezoelectric layer 70 due to moisture and separation of the second electrode 80 and the piezoelectric layer 70 due to moisture can be suppressed.

In addition, by forming the first moisture barrier layer 200 and the second moisture barrier layer 210 from different materials, the first moisture barrier layer 200 can achieve moisture permeation without applying a voltage to the active portion 310 . A material with a low modulus can be used, the diaphragm 50 can be protected from moisture, and the second moisture barrier layer 210 can apply a voltage to the active portion 310 and Any material suitable for deformation can be used.

In addition, it is preferable that the first moisture barrier layer 200 and the second moisture barrier layer 210 are arranged so that at least a part of them overlap each other in the third direction Z, which is the stacking direction. According to this, in the third direction Z, the overlapping portion of the diaphragm 50 from the second concave portion 71 to the active portion 310 is covered with the first moisture barrier layer 200 and the second moisture barrier layer 210. Therefore, the diaphragm 50 in this portion can be reliably protected from moisture.

Of course, the first moisture barrier layer 200 and the second moisture barrier layer 210 may be arranged so that at least a part thereof does not overlap each other in the third direction Z.

Also, the second moisture barrier layer 210 is preferably made of metal. According to this, a voltage can be applied from the second electrode 80 to the active portion 310 of the piezoelectric layer 70 .

(Embodiment 3)
FIG. 7 is a cross-sectional view of a principal part of an ink jet recording head, which is an example of a liquid jet head according to Embodiment 3 of the present invention, and is a cross-sectional view according to line BB′ of FIG. 2, and FIG. 3 is a cross-sectional view of the essential parts of the ink jet recording head according to Embodiment 3, and is a cross-sectional view corresponding to line AA' of FIG. 2. FIG. In addition, the same code|symbol is attached|subjected to the member similar to embodiment mentioned above, and the overlapping description is abbreviate|omitted.

As shown in FIG. 7, in the third direction Z, the region of the piezoelectric layer 70 on the opposite side of the diaphragm 50 from the flow path forming substrate 10 and overlapping at least the bottom surface 711 of the second recess 71 has , a first moisture barrier layer 200A formed of a material different from that of the second electrode 80 is provided. In the present embodiment, the second recess 71 is provided so as to penetrate the piezoelectric layer 70 in the third direction Z, which is the stacking direction. A barrier layer 200A is provided between the diaphragm 50 and the second electrode 80 . That is, since the second recessed portion 71 is provided so as to penetrate the piezoelectric layer 70 in the third direction Z, on the bottom surface 711 of the second recessed portion 71 , the vibration plate 50 and the first , the moisture barrier layer 200 and the second electrode 80 are laminated in this order.

Also, the first moisture barrier layer 200A extends from the region overlapping the bottom surface 711 of the second recess 71 toward the active portion 310 side. The portion of the first moisture barrier layer 200 extending from the bottom surface 711 of the second recess 71 toward the active portion 310 is provided between the vibration plate 50 and the piezoelectric layer 70 in this embodiment. It is That is, the first moisture barrier layer 200A is provided on the surface of the vibration plate 50 opposite to the flow path forming substrate 10 .

Such a first moisture barrier layer 200A is not provided in part of the region overlapping the active portion 310 in the third direction Z. As shown in FIG. In this embodiment, the first moisture barrier layer 200 is not provided up to the first electrode 60 and is not provided in the entire region overlapping the active portion 310 . That is, the opening 201 of the first moisture barrier layer 200A is provided with a width wider than that of the first electrode 60 in the first direction X. As shown in FIG.

By providing the first moisture barrier layer 200A on the vibration plate 50 in this manner, the first moisture barrier layer 200 can be formed on the vibration plate 50 when the first moisture barrier layer 200A is formed and patterned. Since the patterning can be performed on the plane of , the patterning accuracy can be improved, and variations in the displacement characteristics of the piezoelectric element 300 due to the positional deviation of the opening 201 can be suppressed.

A material that can withstand firing of the piezoelectric layer 70 is required for the first moisture barrier layer 200A, and it is preferable to use a metal, particularly a noble metal. By using a metal as the first moisture barrier layer 200A, the first moisture barrier layer 200A can be annealed at the same time as the piezoelectric layer 70 is fired. The process of processing becomes unnecessary, and cost can be reduced. Further, by annealing the first moisture barrier layer 200A, the formation of pinholes or the like in the first moisture barrier layer 200A can be suppressed, and the moisture barrier properties can be improved.

Also, the first moisture barrier layer 200A is provided on the zirconium oxide layer 52 outside the piezoelectric actuator 300 in the second direction Y. As shown in FIG. For example, when an insulating material is used as the first moisture barrier layer 200A, as shown in FIG. , and between the individual wirings 91 arranged side by side in the first direction X. When the first moisture barrier layer 200A is made of a conductive material, the first moisture barrier layer 200A has the same structure as that shown in FIG. Alternatively, although not shown, a first moisture barrier layer 200A is provided between the individual wirings 91 adjacent to each other in the first direction X. It must be set selectively.

In addition, the first moisture barrier layer 200A of the present embodiment extends from above the zirconium oxide layer 52 toward the active portion 310 in the second direction Y, and the active portion of the first moisture barrier layer 200A extends toward the active portion 310. The portion extending toward 310 extends between the piezoelectric layer 70 and the zirconium oxide layer 52 , that is, between the piezoelectric layer 70 and the zirconium oxide layer 52 or the first electrode 60 .

Note that the first moisture barrier layer 200A is not provided in part of the region overlapping the active portion 310 in the third direction Z, even in the second direction Y. That is, the first moisture barrier layer 200A extends over the active portion 310 on the other end side in the second direction Y, and extends over the active portion 310 on the one end side in the second direction Y. It is provided outside, that is, outside the first electrode 60 . The first moisture barrier layer 200</b>A is provided with an opening 201 opening to the main portion of the active portion 310 . By providing the openings 201 in the first moisture barrier layer 200A in this manner, the first moisture barrier layer 200A suppresses the inhibition of deformation of the piezoelectric actuator 300, thereby reducing the amount of displacement of the piezoelectric actuator 300. can be suppressed.

As described above, in this embodiment, the portion of the first moisture barrier layer 200A extending toward the active portion 310 is provided between the vibration plate 50 and the piezoelectric layer 70 .

In this way, by providing the second recess 71 in the piezoelectric layer 70, the displacement characteristics of the piezoelectric element 300 can be improved. By providing the first moisture barrier layer 200A, the diaphragm 50 can be protected from moisture. Therefore, it is possible to suppress breakage of diaphragm 50 due to changes in the characteristics of diaphragm 50 due to reaction of zirconium oxide contained in diaphragm 50 with moisture.

In addition, by providing the portion of the first moisture barrier layer 200A extending toward the active portion 310 between the vibration plate 50 and the piezoelectric layer 70, the region of the zirconium oxide layer 52 close to the external atmosphere becomes the first moisture barrier layer 200A. can be covered and protected by the moisture barrier layer 200A, and the reaction of the zirconium oxide layer 52 with moisture can be reliably suppressed. That is, even if the piezoelectric layer 70 is interposed between the second concave portion 71 and the zirconium oxide layer 52, if the thickness of the intervening piezoelectric layer 70 is thin, moisture that has permeated the second electrode 80 will be absorbed into the zirconium oxide layer 52. There is a risk of reaching the layer 52 . In the present embodiment, the first moisture barrier layer 200A is extended toward the active portion 310 and the extended portion is provided between the vibration plate 50 and the piezoelectric layer 70, so that the piezoelectric layer is relatively thin. Moisture passing through 70 can be suppressed from reaching the zirconium oxide layer 52 .

Also, by covering the zirconium oxide layer 52 exposed on both sides of the piezoelectric actuator 300 in the second direction Y, the zirconium oxide layer 52 on both sides of the piezoelectric actuator 300 in the second direction Y is protected from moisture. be able to. Therefore, even in the second direction Y, the reaction between the zirconium oxide layer 52 and moisture, which causes breakage of the diaphragm 50, can be suppressed, and breakage of the diaphragm 50 can be suppressed in a high-humidity environment or the like. can.

In addition, by providing the first moisture barrier layer 200A between the individual wiring 91 and the first electrode 60 at the end of the piezoelectric actuator 300 on the side of the individual wiring 91 in the second direction Y, moisture is prevented from and the first electrode 60 to prevent it from penetrating into the zirconium oxide layer 52, thereby protecting the zirconium oxide layer 52 from moisture.

(Embodiment 4)
FIG. 9 is a cross-sectional view of a principal part of an ink jet recording head, which is an example of a liquid jet head according to Embodiment 4 of the present invention, and is a cross-sectional view according to line BB' of FIG. In addition, the same code|symbol is attached|subjected to the member similar to embodiment mentioned above, and the overlapping description is abbreviate|omitted.

As shown in FIG. 9, the piezoelectric element 300 of this embodiment is provided with a first moisture barrier layer 200A and a second moisture barrier layer 210 .

The first moisture barrier layer 200A is the same member as in the third embodiment described above. That is, the first moisture barrier layer 200A is provided between the vibration plate 50 and the second electrode 80 in the region overlapping the bottom surface 711 of the second concave portion 71 in the third direction Z. As shown in FIG. That is, since the second recessed portion 71 is provided so as to penetrate the piezoelectric layer 70 in the third direction Z, on the bottom surface 711 of the second recessed portion 71 , the vibration plate 50 and the first , the moisture barrier layer 200 and the second electrode 80 are laminated in this order. As the first moisture barrier layer 200A, a material similar to that of the third embodiment can be used.

The second moisture barrier layer 210 is the same member as in the second embodiment described above, and a material different from that of the first moisture barrier layer 200 is placed between the piezoelectric layer 70 of the active section 310 and the second electrode 80 . It is formed by As the second moisture barrier layer 210, the same material as in the second embodiment can be used.

The first moisture barrier layer 200 and the second moisture barrier layer 210 are arranged so that at least a part thereof overlaps with each other in the third direction Z, which is the direction in which the flow path forming substrate 10 and the piezoelectric element 300 are stacked. It is That is, in the present embodiment, the second moisture barrier layer 210 extends from the active portion 310 to the outside of the active portion 310, and the extended portion is the first moisture barrier layer 200 and the second moisture barrier layer 200. is arranged so as to overlap in the third direction Z with the moisture barrier layer 210 of .

In this way, by arranging the first moisture barrier layer 200 and the second moisture barrier layer 210 so that at least a part thereof overlaps in the third direction Z, moisture permeating through the second electrode 80 is transmitted to the diaphragm. Permeation to the 50 side can be reliably suppressed, and problems due to moisture on the diaphragm 50 can be suppressed.

By using a conductive material for the second moisture barrier layer 210 , a voltage can be applied to the active portion 310 of the piezoelectric layer 70 from the second electrode 80 via the second moisture barrier layer 210 . . In addition, by forming the first moisture barrier layer 200 and the second moisture barrier layer 210 from different materials, the first moisture barrier layer 200 can achieve moisture permeation without applying a voltage to the active portion 310 . A material with a low modulus can be used, the diaphragm 50 can be protected from moisture, and the second moisture barrier layer 210 can apply a voltage to the active portion 310 and Any material suitable for deformation can be used.

Also, by providing the second moisture barrier layer 210 , the piezoelectric layer 70 can be protected from moisture permeating the second electrode 80 even in the active portion 310 . Therefore, deterioration of the piezoelectric layer 70 due to moisture and separation of the second electrode 80 and the piezoelectric layer 70 due to moisture can be suppressed. In other words, the second electrode 80 and the second moisture barrier layer 210 can be firmly bonded by being made of metal, and the moisture permeating the second electrode 80 is unlikely to cause separation between the two. In addition, the second moisture barrier layer 210 makes it difficult for moisture that has permeated the second electrode 80 to permeate the piezoelectric layer 70 , so that the second moisture barrier layer 210 and the piezoelectric layer 70 are separated from each other by moisture. hard.

In addition, in the third direction Z, which is the lamination direction of the flow path forming substrate 10 and the piezoelectric element 300, the first moisture barrier layer 200 and the second moisture barrier layer 210 are arranged at positions at least partially overlapping each other. It is That is, in the present embodiment, the second moisture barrier layer 210 extends from the active portion 310 to the outside of the active portion 310, and the extended portion is the first moisture barrier layer 200 and the second moisture barrier layer 200. is arranged so as to overlap in the third direction Z with the moisture barrier layer 210 of .

In this way, by arranging the first moisture barrier layer 200 and the second moisture barrier layer 210 so that at least a part thereof overlaps in the third direction Z, moisture permeating through the second electrode 80 is transmitted to the diaphragm. Permeation to the 50 side can be reliably suppressed, and problems due to moisture on the diaphragm 50 can be suppressed.

As described above, in the present embodiment, between the piezoelectric layer 70 of the active section 310 and the second electrode 80, the second moisture barrier layer made of a material different from that of the first moisture barrier layer 200 is provided. A layer 210 is provided. By providing the second moisture barrier layer 210 in the active portion 310 in this manner, the piezoelectric layer 70 can be protected from moisture permeating the second electrode 80 also in the active portion 310 . Therefore, deterioration of the piezoelectric layer 70 due to moisture and separation of the second electrode 80 and the piezoelectric layer 70 due to moisture can be suppressed.

In addition, by forming the first moisture barrier layer 200 and the second moisture barrier layer 210 from different materials, the first moisture barrier layer 200 can achieve moisture permeation without applying a voltage to the active portion 310 . A material with a low modulus can be used, the diaphragm 50 can be protected from moisture, and the second moisture barrier layer 210 can apply a voltage to the active portion 310 and Any material suitable for deformation can be used.

In addition, it is preferable that the first moisture barrier layer 200 and the second moisture barrier layer 210 are arranged so that at least a part of them overlap each other in the third direction Z, which is the stacking direction. According to this, in the third direction Z, the overlapping portion of the diaphragm 50 from the second concave portion 71 to the active portion 310 is covered with the first moisture barrier layer 200 and the second moisture barrier layer 210. Therefore, the diaphragm 50 in this portion can be reliably protected from moisture.

Of course, the first moisture barrier layer 200 and the second moisture barrier layer 210 may be arranged so that at least a part thereof does not overlap each other in the third direction Z.

Also, the second moisture barrier layer 210 is preferably made of metal. According to this, a voltage can be applied from the second electrode 80 to the active portion 310 of the piezoelectric layer 70 .

(Embodiment 5)
FIG. 10 is a cross-sectional view of a main part of an ink jet recording head, which is an example of a liquid jet head according to Embodiment 5 of the present invention, and is a cross-sectional view according to line BB' of FIG. In addition, the same code|symbol is attached|subjected to the member similar to embodiment mentioned above, and the overlapping description is abbreviate|omitted.

As shown in FIG. 10, in the present embodiment, the second concave portion 71 does not penetrate the piezoelectric layer 70 in the third direction Z, which is the stacking direction, and leaves the piezoelectric layer 70 on the bottom surface 711 side. is formed by The piezoelectric element 300 is provided with the first moisture barrier layer 200 similar to that of the first embodiment described above. That is, the first moisture barrier layer 200 includes the vibration plate 50, the first moisture barrier layer 200, the piezoelectric layer 70, and the second electrode 80 on the bottom surface 711 of the second concave portion 71 from the flow path forming substrate 10 side. They are stacked in order.

Even with such a configuration, as in the first embodiment described above, the displacement characteristics of the piezoelectric element 300 can be improved by providing the second concave portion 71, and the vibration plate 50 can be displaced by providing the second concave portion 71. By providing the first moisture barrier layer 200, the vibration plate 50 can be protected from moisture even when it comes close to the outside atmosphere. Therefore, it is possible to suppress breakage of diaphragm 50 due to changes in the characteristics of diaphragm 50 due to reaction of zirconium oxide contained in diaphragm 50 with moisture.

In this embodiment, the structure provided with the first moisture barrier layer 200 similar to that of the above-described first embodiment was exemplified, but it is not particularly limited to this. It may be applied to Embodiments 2 to 4 and Embodiment 6 described later.

(Embodiment 6)
FIG. 11 is a cross-sectional view of a main part of an ink jet recording head, which is an example of a liquid jet head according to Embodiment 6 of the present invention, and is a cross-sectional view according to line BB' of FIG. In addition, the same code|symbol is attached|subjected to the member similar to embodiment mentioned above, and the overlapping description is abbreviate|omitted.

As shown in FIG. 11, the second electrode 80 of this embodiment is not formed on the inner surface of the second recess 71, that is, on the bottom surface 711 and side surfaces 712. As shown in FIG. The piezoelectric element 300 is provided with the first moisture barrier layer 200 similar to that of the first embodiment described above. That is, in the first moisture barrier layer 200 , the vibrating plate 50 and the first moisture barrier layer 200 are laminated in this order from the flow path forming substrate 10 side on the bottom surface 711 of the second concave portion 71 .

Even with such a configuration, as in the first embodiment described above, the displacement characteristics of the piezoelectric element 300 can be improved by providing the second concave portion 71, and the vibration plate 50 can be displaced by providing the second concave portion 71. By providing the first moisture barrier layer 200, the vibration plate 50 can be protected from moisture even when it comes close to the outside atmosphere. Therefore, it is possible to prevent the zirconium oxide contained in the diaphragm 50 from reacting with moisture and changing the characteristics of the diaphragm 50, thereby preventing the diaphragm 50 from being destroyed. That is, even if the diaphragm 50 is exposed to the outside by the second concave portion 71, the diaphragm 50 can be prevented from Can be protected from water.

In this embodiment, the structure provided with the first moisture barrier layer 200 similar to that of the above-described first embodiment was exemplified, but it is not particularly limited to this. It may be applied to Embodiments 2-5.

(Other embodiments)
Although each embodiment of the present invention has been described above, the basic configuration of the present invention is not limited to the above.

For example, in each of the above-described embodiments, the communication plate 15 and the nozzle plate 20 are provided on the Z2 side of the flow path forming substrate 10, but this is not a particular limitation. The nozzle plate 20 may be directly adhered to the surface of the channel forming substrate 10 on the Z2 side.

Further, in each of the above-described embodiments, a single crystal silicon substrate is used as the channel forming substrate 10, but the present invention is not limited to this. can be

In the above-described Embodiments 1, 2, 5, and 6, the first moisture barrier layer 200 extends outward from the active portion 310 on the Z1 side surface of the piezoelectric layer 70 in the cross section in the first direction X. The first moisture barrier layer 200 is located inside the active portion 310 on the Z1 side surface of the piezoelectric layer 70 in the first direction X cross section. That is, it may be provided in a region overlapping the active portion 310 in the third direction Z. FIG. That is, the first moisture barrier layer 200 may have openings 201 that are smaller than the active portion 310 . Of course, even in Embodiments 3 and 4, if an insulating material is used as the first moisture barrier layer 200A, the opening 201 of the first moisture barrier layer 200A may be the first electrode 60. You may provide so that it may become narrower than the width|variety of the 1st direction X. FIG.

Such a recording head 1 is mounted in an ink jet recording apparatus I. As shown in FIG. FIG. 12 is a schematic diagram showing an example of an ink jet recording apparatus according to this embodiment.

In the ink jet recording apparatus I shown in FIG. 12, a recording head 1 is detachably provided with a cartridge 2 constituting liquid supply means. It is provided axially movably on the shaft 5 .

The driving force of the drive motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 (not shown), so that the carriage 3 with the recording head 1 mounted thereon is moved along the carriage shaft 5 . On the other hand, the apparatus main body 4 is provided with a transport roller 8 as transport means, and the transport roller 8 transports a recording sheet S, which is a recording medium such as paper. The conveying means for conveying the recording sheet S is not limited to the conveying roller, and may be a belt, a drum, or the like.

In the example described above, the ink jet recording apparatus I has a configuration in which the cartridge 2, which is the ink supply means, is mounted on the carriage 3. However, it is not limited to this. It may be fixed to the apparatus main body 4 and the liquid supply means and the recording head 1 may be connected via a supply pipe such as a tube. Also, the liquid supply means may not be mounted on the ink jet recording apparatus.

Further, in the above-described ink jet recording apparatus I, the recording head 1 is mounted on the carriage 3 and moves in the main scanning direction, but is not limited to this. The present invention can also be applied to a so-called line-type recording apparatus that prints by simply moving a recording sheet S such as paper in the sub-scanning direction.

In addition, the present invention broadly applies to liquid jet heads in general, and for example, to manufacture recording heads such as various ink jet recording heads used in image recording apparatuses such as printers, and color filters such as liquid crystal displays. It can also be applied to a coloring material ejection head, an electrode material ejection head used to form electrodes for organic EL displays, FEDs (field emission displays), etc., and a bioorganic matter ejection head used to manufacture biochips. Further, although the ink jet recording apparatus I has been described as an example of the liquid ejecting apparatus, it is also possible to use the liquid ejecting apparatus using the other liquid ejecting heads described above.

Moreover, the present invention is not limited to the liquid jet head, and can be applied to other piezoelectric devices having a substrate provided with recesses and piezoelectric actuators. Other piezoelectric devices include, for example, ultrasonic devices such as ultrasonic oscillators, ultrasonic motors, temperature-electrical converters, pressure-electrical converters, ferroelectric transistors, piezoelectric transformers, and shielding of harmful rays such as infrared rays. Filters, optical filters using photonic crystal effect by forming quantum dots, filters such as optical filters using optical interference of thin films, infrared sensors, ultrasonic sensors, thermal sensors, pressure sensors, pyroelectric sensors, and gyro sensors ( various sensors such as angular velocity sensors), ferroelectric memory, and the like.

I... Inkjet recording apparatus (liquid ejecting apparatus), 1... Inkjet recording head (liquid ejecting head), 2... Cartridge, 3... Carriage, 4... Apparatus body, 5... Carriage shaft, 6... Drive motor, 7... Timing Belt 8 Conveying roller 10 Flow path forming substrate (substrate) 11 Partition wall 12 Pressure generating chamber (first concave portion) 15 Communication plate 16 Nozzle communication passage 17 First manifold part DESCRIPTION OF SYMBOLS 18... 2nd manifold part 19... Supply communication path 20... Nozzle plate 20a... Liquid injection surface 21... Nozzle 30... Protection board 31... Holding part 32... Through hole 40... Case member 41... Recessed portion 42 Third manifold portion 43 Connection port 44 Introduction path 45 Compliance substrate 46 Sealing film 47 Fixed substrate 48 Opening for fixed substrate 49 Compliance portion 50 Diaphragm 51 Elastic film 52 Zirconium oxide layer 60 First electrode 70 Piezoelectric layer 71 Second concave portion 711 Bottom surface 712 Side surface 80 Second electrode 91 Individual wiring , 92... common wiring, 100... manifold, 120... flexible cable, 121... drive circuit, 200, 200A... first moisture barrier layer, 201... opening, 202... contact hole, 210... second moisture barrier layer, 300 Piezoelectric element (piezoelectric actuator) 310 Active part S Recording sheet X First direction Y Second direction Z Third direction

Claims (12)

a substrate on which a plurality of first recesses are formed;
a diaphragm provided on one surface side of the substrate, the diaphragm having a zirconium oxide layer containing zirconium oxide as the uppermost layer on the side opposite to the substrate;
a piezoelectric element having a first electrode provided on one side of the substrate via the diaphragm, a piezoelectric layer provided on the first electrode, and a second electrode provided on the piezoelectric layer; ,
and
In the piezoelectric element, an active portion of the piezoelectric layer sandwiched between the first electrode and the second electrode is provided independently for each first recess,
the plurality of active portions are arranged side by side in a first direction;
the piezoelectric element includes an inactive portion of the piezoelectric layer that is not sandwiched between the first electrode and the second electrode, adjacent to the active portion;
The first electrode constitutes an individual electrode provided independently for each of the active portions,
The second electrode constitutes a common electrode provided in common to the plurality of active portions,
The piezoelectric layer has a second electrode provided outside the active portion and opening on the side opposite to the substrate.
A recess is provided,
A first piezoelectric element made of a material other than the zirconium oxide is provided in a region of the vibration plate opposite to the substrate in the lamination direction of the substrate and the piezoelectric element and overlapping with the bottom surface of the second recess. A moisture barrier layer of
The first moisture barrier layer extends along the first direction from a region overlapping the bottom surface of the second recess in the stacking direction to a region overlapping the inactive portion in the stacking direction,
The first moisture barrier layer is provided between the vibration plate and the piezoelectric layer in a region overlapping the inactive portion in the stacking direction,
The piezoelectric device according to claim 1, wherein the first moisture barrier layer is not formed in a region overlapping the active portion in the stacking direction. 2. The piezoelectric device according to claim 1, wherein the second concave portions are provided on both sides of the active portion in the first direction. 3. The piezoelectric device according to claim 1, wherein the second recess and the first recess are arranged at a position where at least a part of the recess overlaps in the stacking direction. 2. The first moisture barrier layer provided in a region overlapping the bottom surface of the second recess in the stacking direction is provided between the vibration plate and the second electrode.
4. The piezoelectric device according to any one of 1 to 3. The piezoelectric device according to any one of claims 1 to 4, wherein the first moisture barrier layer is metal. 5. The piezoelectric device according to claim 1, wherein said first moisture barrier layer is an amorphous oxide film or nitride film. The second recess is provided to penetrate the piezoelectric layer in the stacking direction,
On the bottom surface of the second recess, from the substrate side, the vibration plate, the first moisture barrier layer,
7. The piezoelectric device according to claim 1, wherein the second electrodes are laminated in this order. A second moisture barrier layer formed of a material different from that of the first moisture barrier layer is provided between the piezoelectric layer of the active portion and the second electrode. Claim 1 to
8. The piezoelectric device according to any one of 7. 9. The piezoelectric device according to claim 8, wherein the first moisture barrier layer and the second moisture barrier layer are arranged at positions at least partially overlapping each other in the stacking direction. 10. The piezoelectric device according to claim 8, wherein said second moisture barrier layer is metal. A liquid jet head comprising the piezoelectric device according to any one of claims 1 to 10. A liquid ejecting apparatus comprising the liquid ejecting head according to claim 11 .

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