JP6766927B2 - Piezoelectric devices, liquid discharge heads, and liquid discharge devices - Google Patents

Description

The present invention relates to a piezoelectric device, a liquid discharge head, and a liquid discharge device, and in particular, a piezoelectric device, a piezoelectric device, a liquid discharge head, and a liquid having a piezoelectric element formed with a flexible surface sandwiched between vacant chambers. Regarding the discharge device.

Piezoelectric devices include piezoelectric elements and are applied to various liquid discharge devices, vibration sensors, and the like. For example, in a liquid discharge device, various liquids are discharged (injected) from a liquid discharge head using a piezoelectric device. As this liquid discharge device, for example, there are image recording devices such as an inkjet printer and an inkjet plotter, but recently, various types of liquid discharge devices are manufactured by taking advantage of the feature that a very small amount of liquid can be accurately landed at a predetermined position. It is also applied to devices. For example, a display manufacturing device that manufactures color filters such as liquid crystal displays, an electrode forming device that forms electrodes such as an organic EL (Electro Luminescence) display and a FED (field emission display), and a chip that manufactures a biochip (biochemical element). It is applied to manufacturing equipment. Then, the recording head for the image recording device ejects liquid ink, and the color material ejection head for the display manufacturing apparatus ejects solutions of each color material of R (Red), G (Green), and B (Blue). Further, the electrode material discharge head for the electrode forming apparatus discharges the liquid electrode material, and the bioorganic matter discharge head for the chip manufacturing apparatus discharges the bioorganic matter solution.

The liquid discharge head using the piezoelectric device is configured to cause a pressure fluctuation in the liquid in the pressure chamber by driving the piezoelectric element, and discharge the liquid from a nozzle leading to the pressure chamber. The pressure chamber is formed by anisotropic etching on a crystalline substrate such as silicon. A part of this pressure chamber is partitioned by a flexible member to form a flexible surface, and a lower electrode and a piezoelectric material made of a piezoelectric material such as lead zirconate titanate (PZT) are formed on the flexible surface. The upper electrodes are laminated by a film forming technique. For example, in the liquid discharge head disclosed in Patent Document 1, the lower electrode of the upper and lower electrodes is an individual electrode patterned for each pressure chamber, and the other upper electrode extends over a plurality of pressure chambers. It is a continuously formed common electrode. By adopting such a configuration, since most of the piezoelectric body is covered with the upper electrode, the upper electrode also functions as a protective film, and the moisture resistance of the piezoelectric body is enhanced. In this configuration, the portion where the upper electrode, the piezoelectric body, and the lower electrode overlap each other in a plan view (that is, when viewed in the stacking direction of each layer) is an active portion that is deformed by applying a voltage to the electrodes.

JP-A-2014-341114

However, in the above configuration, the active portion is formed to the outside of the opening of the pressure chamber. Therefore, when a driving voltage is applied to the upper and lower electrodes, an electric field is also generated at the end of the active portion located outside the opening of the pressure chamber, and the end also tries to move. However, since the area under the end of the active portion is a structure, that is, a portion of the pressure chamber forming substrate in which no vacant chamber such as a pressure chamber is formed, the end of the active portion is actually restrained and moved. Absent. As a result, stress may be concentrated on the end of the active portion, causing cracks, peeling, and the like.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a piezoelectric device, a liquid discharge head, and a liquid discharge device capable of relieving stress at an end portion of an active portion. There is.

[Means 1]
The piezoelectric device of the present invention has been proposed in order to achieve the above object, and includes a vacant member for partitioning a vacant room and a vacant member.
A piezoelectric element provided on one surface of the vacant member with a flexible surface interposed therebetween, and a first electrode, a piezoelectric body, and a second electrode are laminated in this order from the flexible surface side. When,
With
The vacant portion of the vacant member, which is independent of the vacant chamber, is formed at a position where the first electrode, the piezoelectric body, and the second electrode overlap each other in a plan view with respect to the end of the active portion. It is a feature.

According to the present invention, when a vacant portion of the vacant member, which is independent of the vacant chamber, is formed at a position where it overlaps the end of the active portion in a plan view and is intentionally vulnerable, that is, when an external force is applied. Is provided with a weak portion that can be slightly deformed, and this portion relaxes the stress at the time of driving the active portion of the piezoelectric element. As a result, cracks, peeling, and the like are suppressed at the end of the active portion of the piezoelectric element.

[Means 2]
Further, in the configuration of the means 1, the vacant member has a vacant space forming substrate for partitioning the vacant room and a flexible member that functions as the flexible surface.
It is possible to adopt a configuration in which the vacant portion is partitioned by the recess provided in the vacancy forming substrate and the flexible member.

According to this configuration, since the empty portion is provided at a position closer to the end of the active portion, the effect of relaxing the stress at the time of driving the active portion of the piezoelectric element is further improved. As a result, cracks, peeling, and the like are more reliably suppressed at the end of the active portion of the piezoelectric element.

[Means 3]
Further, in the configuration of the means 1, the front vacant member is joined to the first vacancy forming substrate that partitions the vacancy and the surface of the first vacancy forming substrate that is opposite to the piezoelectric element side. With a second vacancy forming substrate, which is
As the vacant portion, a configuration defined by a recess provided in the second vacancy forming substrate and the first vacancy forming substrate can be adopted.

According to this configuration, this vacancy is not provided and is thicker than the first vacancy forming substrate than the first vacancy forming substrate whose thickness is defined by the height (depth) of the vacancy. It is easier to process the recesses by forming the recesses on the second vacancy forming substrate.

[Means 4]
Further, in the configuration of the means 3, the vacant portion includes a first vacant portion partitioned by a recess provided in the first vacancy forming substrate and the second vacancy forming substrate, and the second empty portion. Includes a recess provided in the chamber forming substrate and a second vacant portion partitioned by the first vacancy forming substrate.
In the vacant room member, it is desirable to adopt a configuration in which the first vacant part and the second vacant part are alternately formed along the parallel direction of the vacant rooms.

According to this configuration, the first vacant portion and the second vacant portion are formed alternately, so that the first vacant space forming substrate and the second vacant portion are formed as compared with the configuration in which the vacant portion is formed only on one substrate. Since the decrease in the strength of the vacancy-forming substrates is suppressed, the risk of damage to these substrates can be suppressed.

[Means 5]
Further, in the configuration of the means 3 or the means 4, the flexible surface may adopt a configuration integrally formed with the first vacancy forming substrate.

According to this configuration, in a configuration in which the first vacancy forming substrate and the flexible surface are separate members, the first vacancy forming substrate and the flexible surface may be separated from each other in the vicinity of the end of the active portion when the piezoelectric element is driven. On the other hand, in the configuration in which the first vacant chamber forming substrate and the flexible surface are integrated, the risk of the first vacant chamber forming substrate and the flexible surface being separated when the piezoelectric element is driven can be suppressed. Further, even with such a configuration, a vacant portion is formed from the surface of the first vacancy forming substrate on the side of the second vacancy forming substrate, or a vacant portion is formed on the side of the second vacancy forming substrate. As a result, the empty space can be provided without any problem.

[Means 6]
Further, the liquid discharge head of the present invention includes the piezoelectric device of any one of the above means 1 to 5 and the piezoelectric device.
A nozzle that communicates with the vacant room of the piezoelectric device,
With
The drive of the piezoelectric element in the piezoelectric device causes a pressure fluctuation in the liquid in the air chamber, and the pressure fluctuation causes the liquid to be discharged from the nozzle.

[Means 7]
Further, the liquid discharge device of the present invention is characterized by including the above liquid discharge head.

According to the configurations of the means 6 and the means 7, the stress at the time of driving the active portion of the piezoelectric element is relaxed, and cracks and peeling are suppressed at the end of the active portion of the piezoelectric element, so that the reliability is improved. improves.

It is a perspective view explaining the internal structure of a printer. It is sectional drawing of the main part of a recording head. It is an enlarged sectional view of the area A in FIG. It is a bottom view of the pressure chamber forming substrate. It is an enlarged sectional view of the main part of the recording head in 2nd Embodiment. It is a bottom view of the pressure chamber forming substrate in 3rd Embodiment. It is an enlarged sectional view of the main part of the recording head in 3rd Embodiment. It is an enlarged sectional view of the main part of the recording head in 4th Embodiment. It is a bottom view of the pressure chamber forming substrate in 5th Embodiment. It is a bottom view of the pressure chamber forming substrate of the modification of 5th Embodiment.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In the embodiments described below, various limitations are given as suitable specific examples of the present invention, but the scope of the present invention is the scope of the present invention unless otherwise specified in the following description to limit the present invention. It is not limited to these aspects. Further, in the following, an inkjet printer (hereinafter, printer) which is a kind of liquid ejection device equipped with an inkjet recording head (hereinafter, recording head) which is a kind of liquid ejection head provided with the piezoelectric device according to the present invention. Will be described as an example.

The configuration of the printer 1 will be described with reference to FIG. The printer 1 is a device that ejects liquid ink onto the surface of a recording medium 2 such as recording paper to record an image or the like. The printer 1 includes a recording head 3 for ejecting ink, a carriage 4 to which the recording head 3 is attached, a carriage moving mechanism 5 for moving the carriage 4 in the main scanning direction, and a platen roller 6 for transferring the recording medium 2 in the sub-scanning direction. Etc. are provided. Here, the above-mentioned ink is a kind of liquid, and is stored in the ink cartridge 7 as a liquid supply source. The ink cartridge 7 is detachably attached to the recording head 3. It is also possible to adopt a configuration in which the ink cartridge 7 is arranged on the main body side of the printer 1 and is supplied from the ink cartridge 7 to the recording head 3 through the ink supply tube.

FIG. 2 is a cross-sectional view illustrating the configuration of the main portion of the recording head 3. Further, FIG. 3 is an enlarged cross-sectional view of the region A in FIG. The recording head 3 in the present embodiment includes a pressure generating unit 9 and a flow path unit 12, and is configured to be attached to a case 17 in a state in which these members are laminated. The flow path unit 12 has a nozzle plate 13, a compliance substrate 16, and a communication substrate 14 (corresponding to the second vacancy forming substrate in the present invention). Further, the pressure generating unit 9 is unitized by laminating the pressure chamber forming substrate 20 (corresponding to the first vacant chamber forming substrate in the present invention) in which the pressure chamber 22 is formed, the piezoelectric element 26, and the sealing plate 15. ing.

The case 17 is, for example, a box-shaped member made of synthetic resin, and a communication board 14 to which the nozzle plate 13 and the pressure generating unit 9 are joined is fixed to the bottom surface side. On the lower surface side of the case 17, a storage space 19 recessed in a rectangular parallelepiped shape from the lower surface to the middle of the case 17 in the height direction is formed. When the flow path unit 12 is joined to the lower surface of the case 17 in a positioned state, the pressure generating unit 9 laminated on the communication board 14 is accommodated in the accommodation space 19. Further, an ink introduction empty portion 24 is formed in the case 17. The ink introduction empty space 24 is an empty space into which ink from the ink cartridge 7 side is introduced. The ink that has flowed into the ink introduction empty space 24 is introduced into the common liquid chamber 23 (described later) of the communication substrate 14.

FIG. 4 is a bottom view of the pressure chamber forming substrate 20 (the joint surface side with the communicating substrate 14). In the figure, the portion indicated by the broken line indicates the lower electrode 30 of the piezoelectric element 26 (corresponding to the first electrode in the present invention), and the portion indicated by the alternate long and short dash line indicates the upper electrode 32 of the piezoelectric element 26 (the second electrode in the present invention). Corresponds to the electrode). The pressure chamber forming substrate 20 which is a constituent member of the pressure generating unit 9 is made of a silicon single crystal substrate (hereinafter, also simply referred to as a silicon substrate). In the pressure chamber forming substrate 20, a part of a plurality of pressure chambers 22 (corresponding to vacant chambers in the present invention), in the present embodiment, a pressure chamber vacant portion mainly for partitioning a side wall and a ceiling surface is a nozzle plate 13. A plurality of nozzles 18 are formed corresponding to the plurality of nozzles 18 provided in the above. The empty part of the pressure chamber is a space formed halfway in the thickness direction of the pressure chamber forming substrate 20 by etching from the lower surface side of the pressure chamber forming substrate 20 and leaving a thin thin portion on the upper surface side. The thin portion functions as a flexible surface 21 that deforms as the piezoelectric element 26 is driven. That is, in the present embodiment, the pressure chamber forming substrate 20 and the flexible surface 21 are integrally formed. The pressure chamber 22 is partitioned by closing the opening portion on the lower surface side of the pressure chamber vacant portion with the communication substrate 14 described later. Hereinafter, the pressure chamber 22 including the empty space of the pressure chamber will be referred to as appropriate.

The pressure chamber 22 in the present embodiment has a substantially parallel quadrilateral shape that is long in a direction orthogonal to the nozzle row direction in a plan view (state seen in the stacking direction of the pressure chamber substrate 20, the communicating substrate 14, and other constituent members). It is vacant. Further, the wall 22w at the end in the longitudinal direction of the pressure chamber in the pressure chamber 22 (vacant portion of the pressure chamber) is inclined with respect to the upper and lower surfaces of the pressure chamber forming substrate 20. Specifically, the wall 22w is inclined so as to be inward of the pressure chamber 22 toward the upper surface of the pressure chamber forming substrate 20. Each pressure chamber 22 is provided in each nozzle 18 of the nozzle plate 13 in a one-to-one correspondence. That is, the formation pitch of each pressure chamber 22 corresponds to the formation pitch of the nozzle 18.

When the pressure chamber forming substrate 20 is joined in a state of being positioned with respect to the communication substrate 14, one end of the pressure chamber 22 in the longitudinal direction communicates with the nozzle 18 via the nozzle communication passage 27 of the communication substrate 14, which will be described later. .. Further, the other end of the pressure chamber 22 in the longitudinal direction communicates with the common liquid chamber 23 via the supply port 28 of the communication board 14. In the present embodiment, the laminate composed of the pressure chamber forming substrate 20 and the communicating substrate 14 corresponds to the vacant chamber member in the present invention. The combination of the vacant member and the piezoelectric element 26 corresponds to the piezoelectric device of the present invention.

In the present embodiment, on the lower surface side of the pressure chamber forming substrate 20, on both sides in the longitudinal direction of the pressure chamber 22, bottomed recesses 34 shallower than the pressure chamber 22 are formed in the thickness direction of the pressure chamber forming substrate 20. It is formed halfway. That is, in the recess 34, in a state where the portion corresponding to the bottom plate of the recess 34 is left as the fragile portion 36, in a plan view from the lower surface side of the pressure chamber forming substrate 20 as in the pressure chamber 22 by anisotropic etching. It is formed in a substantially parallel quadrilateral shape. The opening on the lower surface side of the recess 34 is closed by the communicating substrate 14 by joining the communicating substrate 14 to the lower surface of the pressure chamber forming substrate 20. As a result, the empty portion 35 is partitioned by the recess 34 of the pressure chamber forming substrate 20 and the communication substrate 14. As shown in FIG. 4, two empty portions 35 are formed for each pressure chamber 22 at positions overlapping with both ends E of the active portions of the piezoelectric element 26 in a plan view. The empty space 35 is a space independent of the flow path through which ink flows, such as the pressure chamber 22, and is filled with air.

The piezoelectric element 26 is formed at a position (region corresponding to the flexible surface 21) corresponding to each pressure chamber 22 on the upper surface of the pressure chamber forming substrate 20. The piezoelectric element 26 in the present embodiment is a so-called bending mode piezoelectric element. The piezoelectric element 26 is configured by sequentially laminating a metal lower electrode 30, a piezoelectric body 31 made of lead zirconate titanate (PZT), etc., and a metal upper electrode 32 on a pressure chamber forming substrate 20. Has been done. The piezoelectric element 26 in the present embodiment is located on the pressure chamber forming substrate 20 at a position beyond the longitudinal end of the pressure chamber 22 and outside the pressure chamber 22 (a position outside the flexible surface 21). Has been extended to. Then, as shown in FIGS. 3 and 4, the lower electrode 30 and the piezoelectric body 31 are further extended to a position outside in the same direction as the end portion of the upper electrode 32 in the longitudinal direction of the pressure chamber.

In the present embodiment, the lower electrode 30 and the piezoelectric body 31 are patterned for each pressure chamber 22, and the lower electrode 30 is an individual electrode for each pressure chamber 22. Further, the upper electrode 32 is an electrode common to a plurality of piezoelectric elements 26. Then, in a plan view, that is, in the stacking direction of each layer, the portion where the upper electrode 32, the piezoelectric body 31, and the lower electrode 30 overlap is an active portion where piezoelectric strain is generated by applying a voltage to both electrodes 30 and 32. is there. Therefore, the end of the upper electrode 32 in the longitudinal direction of the pressure chamber substantially defines the end E of the active portion. It is also possible to adopt a configuration in which the lower electrode 30 is a common electrode for the plurality of piezoelectric elements 26 and the upper electrode 32 is an individual electrode for each piezoelectric element 26.

A sealing plate 15 is arranged on the upper surface of the communication substrate 14 on which the piezoelectric element 26 is formed. The sealing plate 15 is made of, for example, glass, a ceramic material, a silicon single crystal substrate, a metal, a synthetic resin, or the like. Inside the sealing plate 15, a piezoelectric element accommodating empty portion 39 having a size that does not hinder the driving of the piezoelectric element 26 is formed in a region facing the piezoelectric element 26. The sealing plate 15 is joined to the upper surface of the communication substrate 14 in a state where the mainly active portion of the piezoelectric element 26 is accommodated in the piezoelectric element accommodating empty portion 39. The sealing plate 15 is formed with a wiring empty portion (not shown) penetrating in the substrate thickness direction, and an electrode terminal extending from the piezoelectric element 26 is arranged in the wiring empty portion. Terminals of wiring members (not shown) are electrically connected to the electrode terminals.

The nozzle plate 13 and the compliance board 16 are joined to the lower surface of the communication board 14. The nozzle plate 13 is a plate material in which a plurality of nozzles 18 are opened, and is made of a silicon substrate in this embodiment. Then, the cylindrical nozzle 18 is formed by performing dry etching on the substrate. The nozzle plate 13 is joined to the central portion of the lower surface of the communication board 14 in a state where each nozzle 18 communicates with the nozzle communication passage 27 of the communication board 14. The compliance substrate 16 is a flexible member joined on the lower surface of the communication substrate 14 so as to close the opening of the common liquid chamber 23. The compliance board 16 has a function of absorbing a pressure change of ink in the common liquid chamber 23.

The communication substrate 14 is a plate material made of a silicon substrate in the same manner as the pressure chamber forming substrate 20. On the communication substrate 14, an empty portion serving as a nozzle communication passage 27 and a common liquid chamber 23 is formed by anisotropic etching. A plurality of nozzle communication passages 27 are formed corresponding to the pressure chambers 22 along the parallel direction (nozzle row direction) of the pressure chambers. With the communication substrate 14 and the pressure chamber forming substrate 20 joined in a positioned state, each nozzle communication passage 27 communicates with one end of the corresponding pressure chamber 22 in the longitudinal direction. The common liquid chamber 23 extends along the nozzle row direction (in other words, the parallel direction of the pressure chambers 22), and is an empty portion into which common ink is introduced into each pressure chamber 22. When the communication board 14 is joined to the case 17 in the positioned state, the common liquid chamber 23 communicates with the ink introduction empty portion 24, and the ink from the ink cartridge 7 is introduced into the common liquid chamber 23 through the ink introduction empty portion 24. .. The common liquid chamber 23 and each pressure chamber 22 communicate with each other via a supply port 28 individually provided for each pressure chamber. Therefore, the ink in the common liquid chamber 23 is distributed and supplied to each pressure chamber 22 through the supply port 28.

Here, in the recording head 3 having the above configuration, the active portion of the piezoelectric element 26 is formed in the pressure chamber forming substrate 20 to a position corresponding to the outside of the flexible surface 21 of the pressure chamber 22. Therefore, when a driving voltage is applied to the upper and lower electrodes 30 and 32, an electric field is generated between the upper and lower electrodes also at the end of the active portion outside the upper opening of the pressure chamber, and the end of the active portion also tries to move. To do. In a conventional recording head having a similar configuration, there is no vacancy such as a pressure chamber in a structure, that is, a substrate on which a pressure chamber is formed, below the end of an active portion outside the flexible surface of the pressure chamber. Since it is a part, the end of the active part is actually restrained and cannot move. As a result, stress may be concentrated on the end of the active portion, causing cracks, peeling, and the like. Regarding such a defect, in the recording head 3 according to the present invention, as described above, an empty portion 35 is formed at a position overlapping both ends E of the active portion of the piezoelectric element 26 in a plan view, and the portion is intentionally fragile. That is, since a weak portion that can be slightly deformed when an external force is applied is provided, this portion relaxes the stress at the time of driving the active portion of the piezoelectric element 26. As a result, cracks and peeling are suppressed at the ends (particularly electrodes) of the active portion of the piezoelectric element 26. Further, since the empty space 35 is a space separate from the ink flow path such as the pressure chamber 22, it does not affect the ink ejection characteristics (weight of ejected ink and flying speed) in the nozzle 18. ..

Here, if the pressure chamber forming substrate and the flexible surface (flexible member) are separate members, the pressure chamber forming substrate and the flexible member may be separated from each other in the vicinity of the end of the active portion when the piezoelectric element is driven. On the other hand, in the present embodiment, since the pressure chamber forming substrate 20 and the flexible surface 21 are integrated, the pressure chamber forming substrate 20 and the flexible surface 21 are separated when the piezoelectric element 26 is driven. You can reduce the risk of doing so. Further, even if the pressure chamber forming substrate 20 and the flexible surface 21 are integrally formed in this way, a recess 34 for partitioning the empty portion 35 is formed on the surface of the pressure chamber forming substrate 20 on the communication substrate 14 side. Therefore, the empty space 35 can be provided without any problem. Further, in the present embodiment, since the recesses can be formed in the pressure chamber forming substrate 20 by the same etching process as in the pressure chamber 22, the number of steps does not increase.

FIG. 5 is a cross-sectional view of a main part of the recording head 3 according to the second embodiment of the present invention. In the first embodiment, the configuration in which the empty portion 35 is partitioned by the recess 34 of the pressure chamber forming substrate 20 and the communication substrate 14 is illustrated, but the present invention is not limited to this. In the second embodiment, the recess 34'is formed on the communication substrate 14 side, and the recess 34'is closed by the pressure chamber forming substrate 20 to form an empty portion 35'. It is different from the embodiment of. That is, from the viewpoint of ensuring the strength of the partition wall between the pressure chambers, the height (depth) of the pressure chamber 22 is formed to be shallower than that of the common liquid chamber 23, the nozzle communication passage 27, and the like. The thickness of the pressure chamber forming substrate 20 is thinner than the thickness of the communicating substrate 14 (for example, in the range of 200 [μm] or more and 500 [μm]) (for example, in the range of 40 [μm] or more and 100 [μm]). ). Therefore, it is easier to process the recess 34'on the thicker communicating substrate 14, and the substrate is less likely to be damaged. Also in this second embodiment, as in the first embodiment, since the empty portion 35'is formed at a position overlapping both ends E of the active portion of the piezoelectric element 26 in a plan view, the active portion of the piezoelectric element 26 is active. The stress at the time of driving the part is relaxed. The other configurations are the same as those of the first embodiment.

6 and 7 are views for explaining the configuration of the third embodiment of the present invention, FIG. 6 is a bottom view of the pressure chamber forming substrate 20, and FIG. 7 is a cross-sectional view of a main part of the recording head 3. is there. In the present embodiment, the first empty portion 35a is partitioned by the recess 34a formed in the pressure chamber forming substrate 20 and the communicating substrate 14, and the recess 34b formed in the communicating substrate 14 and the pressure chamber forming substrate are partitioned. The second vacant portion 35b is formed alternately along the nozzle row direction (the direction in which the pressure chambers are arranged side by side), which is different from the first embodiment and the second embodiment. That is, in the configuration in which the recess is formed only in one of the pressure chamber forming substrate 20 and the communicating substrate 14, the substrate becomes fragile and may be damaged. On the other hand, as in the present embodiment, the first empty portion 35a and the second empty portion 35b are alternately formed, so that the strength of the pressure chamber forming substrate 20 and the communication substrate 14 is suppressed from being lowered. Therefore, the risk of damage or the like can be suppressed. Also in this second embodiment, as in the first embodiment, since the empty portions 35a and 35b are formed at positions overlapping the both ends E of the active portions of the piezoelectric element 26 in a plan view, the piezoelectric element 26 The stress when driving the active part is relaxed. The other configurations are the same as those of the first embodiment.

FIG. 8 is a cross-sectional view of a main part of the recording head 3 according to the fourth embodiment of the present invention. In the first embodiment, the pressure chamber vacant portion of the pressure chamber forming substrate 20 is formed so as to penetrate the thickness direction of the pressure chamber substrate 20, and the elastic film 40 (this) is formed on the pressure chamber forming substrate 20. The pressure chamber 22 is partitioned by joining the flexible member) and the communicating substrate 14 in the present invention. The elastic film 40 is composed of, for example, a first layer made of silicon dioxide (SiO ₂ ) and a second layer made of zirconium oxide (ZrO ₂ ) formed on the first layer. The portion of the elastic film 40 that closes the upper opening of the pressure chamber 22 functions as a flexible surface that deforms as the piezoelectric element 26 (active portion) is driven. Further, a recess 34c is formed in the pressure chamber forming substrate 20 which is recessed halfway in the substrate thickness direction from the upper surface side to the lower surface side. The opening on the upper surface side of the recess 34c is closed by the elastic film 40. As a result, the empty space 35c is partitioned by the recess 34c of the pressure chamber forming substrate 20 and the elastic film 40. According to this configuration, in the stacking direction of the pressure chamber forming substrate 20 and the communication substrate 14, the empty portion 35c is provided at a position closer to the end E of the active portion, so that the stress at the time of driving the active portion of the piezoelectric element 26 is relaxed. The effect of doing is improved. As a result, cracks, peeling, and the like are more reliably suppressed at the end of the active portion of the piezoelectric element 26. The other configurations are the same as those of the first embodiment.

FIG. 9 is a plan view of the pressure chamber substrate 20'in the fifth embodiment of the present invention. The pressure chamber 22'in the present embodiment has an elliptical shape or a rhombic shape in a plan view. Further, in FIG. 9, the portion shown by the broken line indicates the end E of the active portion defined by the shape of the individual electrode of the piezoelectric element. That is, the end E of the active portion in the present embodiment is also located outside the pressure chamber 22'(outside the flexible surface). Then, in the pressure chamber substrate 20'or the substrate constituting the vacant chamber member together with the pressure chamber substrate 20', the groove-shaped vacant portion 35c is located at a position where it overlaps with the end E of the active portion in a plan view. It is formed in an annular shape over the entire circumference of E. Even in such a configuration, the stress at the time of driving the active portion of the piezoelectric element 26 is relaxed by forming the empty portion 35d at a position overlapping the both ends E of the active portion of the piezoelectric element in a plan view. As a result, cracks, peeling, and the like are suppressed at the end of the active portion of the piezoelectric element. As in the modified example shown in FIG. 10, in the configuration in which the supply path 45 communicating with the pressure chamber 22'is formed in the pressure chamber substrate 20', the empty portion 35d is flat so as to avoid the supply path 45. The empty portion 35d does not necessarily have to be formed over the entire circumference of the end E of the active portion, such as being formed in a horseshoe shape visually.

In the above, the configuration of the recording head 3 including the pressure chamber forming substrate 20, the communicating substrate 14, and the piezoelectric element 26 has been described as an example of the piezoelectric device, but the present invention describes the vacant member for partitioning the vacant chamber. And it can also be applied to other piezoelectric devices including piezoelectric elements. Further, as the liquid discharge head, for example, a color material discharge head used for manufacturing a color filter such as a liquid crystal display, an electrode material discharge head used for forming an electrode of an organic EL (Electro Luminescence) display, a FED (surface emitting display) or the like. The present invention can also be applied to a head, a bioorganic substance discharge head used for manufacturing a biochip (biochemical element), and the like.

1 ... Printer, 3 ... Recording head, 9 ... Pressure generating unit, 12 ... Flow path unit, 13 ... Nozzle plate, 14 ... Communication substrate, 15 ... Sealing plate, 18 ... Nozzle, 20 ... Pressure chamber forming substrate, 21 ... Flexible surface, 22 ... Pressure chamber, 23 ... Common liquid chamber, 26 ... Piezoelectric element, 30 ... Lower electrode, 31 ... Piezoelectric body, 32 ... Upper electrode, 34 ... Recession, 35 ... Empty space, 40 ... Elastic film, 42 ... recess, 43 ... empty space, 45 ... supply path

Claims (8)

Vacancy members that partition vacancies and
A piezoelectric element provided on one surface of the vacant member with a flexible surface interposed therebetween, and a first electrode, a piezoelectric body, and a second electrode are laminated in this order from the flexible surface side. When,
With
A vacant portion of the vacant member that is independent of the vacant chamber is formed at a position where the first electrode, the piezoelectric body, and the second electrode overlap each other in a plan view with respect to the end of the active portion .
A piezoelectric device characterized in that the empty portion is formed at both ends of the active portion in a plan view . The vacant member includes a vacant space forming substrate for partitioning the vacant room and a flexible member that functions as the flexible surface.
The piezoelectric device according to claim 1, wherein the vacant portion is partitioned by a recess provided in the vacancy forming substrate and the flexible member. The vacant member includes a first vacancy forming substrate that partitions the vacancy, and a second vacancy forming substrate that is joined to a surface of the first vacancy forming substrate that is opposite to the piezoelectric element side. Have,
The piezoelectric device according to claim 1, wherein the vacant portion is partitioned by a recess provided in the second vacancy forming substrate and the first vacancy forming substrate. The vacant portion includes a recess provided in the first vacancy forming substrate, a first vacant portion partitioned by the second vacancy forming substrate, and a recess provided in the second vacancy forming substrate. Includes a second vacant portion partitioned by the first vacancy forming substrate.
The piezoelectric device according to claim 3, wherein in the vacant member, the first vacant portion and the second vacant portion are alternately formed along the parallel direction of the vacant chamber. The piezoelectric device according to claim 3 or 4, wherein the flexible surface is integrally formed on the first vacancy forming substrate. The piezoelectric device according to any one of claims 1 to 4, wherein the vacant portion has a length from a plan view direction shorter than that of the vacant chamber. The piezoelectric device according to claims 1 any one of claims 6,
A nozzle that communicates with the vacant room of the piezoelectric device,
With
A liquid discharge head characterized in that a pressure fluctuation is caused in a liquid in the air chamber by driving a piezoelectric element in the piezoelectric device, and the liquid is discharged from the nozzle by the pressure fluctuation. A liquid discharge device comprising the liquid discharge head according to claim 7 .

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