JP2014061718A - Liquid jet head, liquid jet device and actuator device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid jet head, a liquid jet device and an actuator device with improved displacement characteristics.SOLUTION: A liquid jet head is equipped with: a pressure generating chamber which communicates with a nozzle opening for jetting liquid; and a piezoelectric element for generating pressure variation to the pressure generating chamber, in which the piezoelectric element comprises: a first electrode; a piezoelectric layer formed on the first electrode and containing titanium (Ti) and zirconium (Zr); and a second electrode formed on the opposite side of the first electrode of the piezoelectric layer. A crystal structure obtained by measuring the piezoelectric layer within a range of 100 to 500 nm from the first electrode in a thickness direction by electronic energy loss spectrometry has a part of monoclinic system structure, fluctuation of Ti/(Ti+Zr)% when a horizontal axis is considered as distance from the first electrode and a vertical axis is considered as Ti/(Ti+Zr)% from a range to become a monoclinic system to a rhombohedral crystal system is within 10%, and fluctuation from the range to become the monoclinic system to a tetragonal system is within 10% for a measurement result.

Description

  The present invention relates to a liquid ejecting head that ejects liquid from a nozzle opening, a liquid ejecting apparatus, and an actuator device having a first electrode, a piezoelectric layer, and a second electrode.

  A piezoelectric element used as pressure generating means for ejecting liquid from a nozzle opening of an ink jet recording head is an element in which a piezoelectric layer made of a piezoelectric material exhibiting an electromechanical conversion function is sandwiched between two electrodes. As a piezoelectric layer used in such a piezoelectric element, a layer containing titanium and zirconium and having a Ti / Zr ratio in the range of 30/70 to 70/30 has been proposed (for example, Patent Documents). 1).

Japanese Patent Laid-Open No. 10-286953

  However, in a piezoelectric element having a piezoelectric layer that only defines the overall Ti / Zr ratio as in Patent Document 1, there is a case where sufficient displacement cannot be obtained. Such a problem is not limited to a piezoelectric element used in an ink jet recording head, but also exists in a piezoelectric element used in a liquid ejecting head that ejects another liquid, and is used in a device other than the liquid ejecting head. It also exists in piezoelectric elements.

  SUMMARY An advantage of some aspects of the invention is that it provides a liquid ejecting head, a liquid ejecting apparatus, and an actuator device that have improved displacement characteristics.

An aspect of the present invention that solves the above-described problem includes a pressure generation chamber that communicates with a nozzle opening that ejects liquid, and a piezoelectric element that causes a pressure change in the pressure generation chamber, and the piezoelectric element includes a first electrode. And a piezoelectric layer formed on the first electrode and containing titanium (Ti) and zirconium (Zr), and a second electrode formed on the opposite side of the piezoelectric layer from the first electrode. In the liquid jet head, the crystal structure of the piezoelectric layer measured in the thickness direction in the range of 100 to 500 nm from the first electrode by electron energy loss spectroscopy has a monoclinic structure portion. From the range of the monoclinic system of Ti / (Ti + Zr)% when the horizontal axis is the distance from the first electrode and the vertical axis is Ti / (Ti + Zr)% in the measurement results, Variation within 10% and monoclinic system Change to tetragonal from range of the a liquid-jet head, characterized in that within 10%.
In this aspect, the crystal structure of the piezoelectric layer measured by the EELS method has a monoclinic structure in the range of 100 to 500 nm from the first electrode, and the horizontal axis of the measurement result is the distance from the first electrode. And the vertical axis is Ti / (Ti + Zr)%, the variation of Ti / (Ti + Zr)% from the range of the monoclinic system to the rhombohedral system is within 10%, and the monoclinic system By adopting a predetermined crystal structure in which the variation from the system range to the tetragonal system is within 10%, a large displacement can be obtained with a low driving voltage, that is, the displacement characteristics can be improved. it can.

  Here, the crystal structure of the piezoelectric layer is preferably different in the thickness direction of the piezoelectric layer. According to this, the displacement characteristics can be further improved.

  The piezoelectric layer may have a thickness of 1 to 2 μm. According to this, even when the piezoelectric layer is a thin film having a thickness of about 1 to 2 μm, a large displacement can be obtained with a low driving voltage.

  The first electrode preferably contains platinum. According to this, a liquid ejecting head having a piezoelectric element having excellent displacement characteristics can be realized.

  According to another aspect of the invention, there is provided a liquid ejecting apparatus including the liquid ejecting head according to the above aspect. According to this aspect, it is possible to realize a liquid ejecting apparatus including a liquid ejecting head that can obtain a large amount of displacement with a low driving voltage, that is, that has improved displacement characteristics.

In another aspect of the present invention, a first electrode, a piezoelectric layer formed on the first electrode and containing titanium (Ti) and zirconium (Zr), the first electrode of the piezoelectric layer, And the second electrode formed on the opposite side, and the crystal structure of the piezoelectric layer measured by electron energy loss spectroscopy in the thickness direction in the range of 100 to 500 nm from the first electrode is a monoclinic crystal A range of a monoclinic system of Ti / (Ti + Zr)% when the horizontal axis is the distance from the first electrode and the vertical axis is Ti / (Ti + Zr)% in the measurement result. The actuator device is characterized in that a change from rhombohedral to a rhombohedral system is within 10%, and a change from a monoclinic system to a tetragonal system is within 10%.
In this aspect, the crystal structure of the piezoelectric layer measured by the EELS method has a monoclinic structure in the range of 100 to 500 nm from the first electrode, and the horizontal axis of the measurement result is the distance from the first electrode. And the vertical axis is Ti / (Ti + Zr)%, the variation of Ti / (Ti + Zr)% from the range of the monoclinic system to the rhombohedral system is within 10%, and the monoclinic system By adopting a predetermined crystal structure in which the variation from the system range to the tetragonal system is within 10%, a large displacement can be obtained with a low driving voltage, that is, the displacement characteristics can be improved. it can.

FIG. 2 is an exploded perspective view illustrating a schematic configuration of the recording head according to the first embodiment. 2A and 2B are a plan view and a cross-sectional view of the recording head according to the first embodiment. It is a figure which shows the result of having measured the piezoelectric material layer which concerns on Embodiment 1 by EELS method. It is a spectrum obtained by EELS measurement. It is a figure showing the example of a relationship between Ti / (Ti + Zr) and the distance of D peak and E peak. It is a figure which shows the result of having measured the crystal structure of the piezoelectric material layer of various piezoelectric elements. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. It is a figure which shows the result of having measured the piezoelectric material layer which concerns on Example 1 by EELS method. It is a figure which shows the result of having measured the piezoelectric material layer which concerns on Example 2 by EELS method. It is a figure which shows the result of having measured the piezoelectric material layer which concerns on the comparative example 1 by EELS method. It is a figure which shows the result of having measured the piezoelectric material layer which concerns on the comparative example 2 by EELS method. It is a figure which shows the result of having measured the piezoelectric material layer which concerns on the comparative example 3 by EELS method. 1 is a diagram illustrating a schematic configuration of a recording apparatus according to an embodiment.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is an exploded perspective view showing a schematic configuration of an ink jet recording head which is an example of a liquid ejecting head according to Embodiment 1 of the present invention. FIG. 2 is a plan view of FIG. FIG.

  As shown in FIGS. 1 and 2, the flow path forming substrate 10 of the present embodiment is made of a silicon single crystal substrate, and an elastic film 50 is formed on one surface thereof.

  A plurality of pressure generating chambers 12 are arranged in parallel in the width direction of the flow path forming substrate 10. In addition, a communication portion 13 is formed in a region outside the longitudinal direction of the pressure generation chamber 12 of the flow path forming substrate 10, and the communication portion 13 and each pressure generation chamber 12 are provided for each pressure generation chamber 12. Communication is made via a supply path 14 and a communication path 15. The communication part 13 communicates with a reservoir part 31 of a protective substrate, which will be described later, and constitutes a part of a reservoir that serves as a common ink chamber for the pressure generating chambers 12. The ink supply path 14 is formed with a narrower width than the pressure generation chamber 12, and maintains a constant flow path resistance of ink flowing into the pressure generation chamber 12 from the communication portion 13. In this embodiment, the ink supply path 14 is formed by narrowing the width of the flow path from one side. However, the ink supply path may be formed by narrowing the width of the flow path from both sides. Further, the ink supply path may be formed by narrowing from the thickness direction instead of narrowing the width of the flow path.

  In this embodiment, the flow path forming substrate 10 is provided with a liquid flow path including the pressure generation chamber 12, the communication portion 13, the ink supply path 14, and the communication path 15.

  Further, on the opening surface side of the flow path forming substrate 10, a nozzle plate 20 having a nozzle opening 21 communicating with the vicinity of the end of each pressure generating chamber 12 on the side opposite to the ink supply path 14 is provided with an adhesive. Or a heat-welded film or the like. The nozzle plate 20 is made of, for example, glass ceramics, a silicon single crystal substrate, stainless steel, or the like.

  On the other hand, the elastic film 50 is formed on the side opposite to the opening surface of the flow path forming substrate 10 as described above, and the insulator film 55 is formed on the elastic film 50. Further, the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are laminated on the insulator film 55 to constitute the piezoelectric element 300. Here, the piezoelectric element 300 refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80. In general, one electrode of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12. In the present embodiment, the first electrode 60 is a common electrode of the piezoelectric element 300, and the second electrode 80 is an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for the convenience of the drive circuit and wiring. In addition, here, the piezoelectric element 300 and the diaphragm that is displaced by driving the piezoelectric element 300 are collectively referred to as an actuator device. In the above-described example, the elastic film 50, the insulator film 55, and the first electrode 60 function as a diaphragm. However, the present invention is not limited to this. For example, the elastic film 50 and the insulator film 55 are provided. Instead, only the first electrode 60 may act as a diaphragm. Further, the piezoelectric element 300 itself may substantially serve as a diaphragm.

The piezoelectric layer 70 is formed on the first electrode 60 and has a perovskite structure, for example, a ferroelectric material containing Zr or Ti as a metal. As the piezoelectric layer 70, for example, a ferroelectric material such as lead zirconate titanate (PZT) or a material obtained by adding a metal oxide such as niobium oxide, nickel oxide, or magnesium oxide to the ferroelectric material is suitable. Specifically, lead zirconate titanate (Pb (Zr, Ti) O ₃ ), barium zirconate titanate (Ba (Zr, Ti) O ₃ ), lead lanthanum zirconate titanate ((Pb, La) ( Zr, Ti) O ₃ ) or lead magnesium niobate zirconium titanate (Pb (Zr, Ti) (Mg, Nb) O ₃ ) or the like can be used.

  The piezoelectric layer 70 is formed thick enough to suppress the thickness so as not to generate cracks in the manufacturing process and to exhibit sufficient displacement characteristics. For example, in this embodiment, the piezoelectric layer 70 is formed with a thickness of about 1 to 2 μm.

  In this embodiment, the crystal structure of the piezoelectric layer 70 measured in the thickness direction from the first electrode 60 to 100 to 500 nm in the thickness direction by electron energy loss spectroscopy (EELS (Electoron Energy Loss Spectroscopy) method) A monoclinic system of Ti / (Ti + Zr)% having a portion of an oblique structure and having a horizontal axis of the measurement results from the first electrode 60 and a vertical axis of Ti / (Ti + Zr)%. The variation of rhombohedral system from the range is within 10%. Further, the variation of the tetragonal system from the range of the monoclinic system of Ti / (Ti + Zr)% is within 10%.

  Specifically, when the piezoelectric layer 70 of the present embodiment is measured in the thickness direction of the piezoelectric layer 70 by the EELS method, the piezoelectric layer 70 is tetragonal on the first electrode 60 side as shown in FIG. From the first electrode 60, the crystal structure around the monoclinic system is different in the thickness direction of the piezoelectric layer from the vicinity of 100 nm, that is, the crystal structure is monotonous around the monoclinic system. The structure is different from that of the oblique system. In FIG. 3, the horizontal axis represents the distance from the first electrode 60 (BE), and the vertical axis represents Ti / (Ti + Zr) (molar ratio)%. In addition, two lines parallel to the horizontal axis shown in the figure are, in order from the top, a line indicating the boundary between the tetragonal system and the monoclinic system, and the monoclinic system and the rhombohedral system. , T represents a tetragonal crystal structure, M represents a monoclinic crystal structure, and R represents a rhombohedral crystal structure. The boundary of this crystal structure can also be obtained by the EELS method. More specifically, when EELS measurement is performed, a spectrum at each Ti / (Ti + Zr) as shown in FIG. 4 is obtained. When the crystal structure is a tetragonal system, the B peak shown in FIG. 4 disappears, so it can be determined from the spectrum whether the crystal structure is a tetragonal system. Further, the distance between the D peak and the E peak shown in FIG. 4 is almost constant in the monoclinic system, but is attenuated when the rhombohedral system is used. Can be identified. For example, in FIG. 5 showing an example of the relationship between Ti / (Ti + Zr) and the distance between the D peak and the E peak, there are a region where the distance between the D peak and the E peak is substantially constant and a region where the peak distance is attenuated. When this occurs (46% in FIG. 5), the boundary between the rhombohedral system and the monoclinic system is obtained. Thus, the boundary of the crystal structure can be obtained by the EELS method. As will be described later, the boundary of the crystal structure is not determined only by Ti / (Ti + Zr), but varies depending on conditions such as stress. However, the boundary of the crystal structure can be found by performing EELS measurement.

Then, as shown in FIG. 3, the piezoelectric layer 70 of the present embodiment has a rhombohedral in order from the first electrode 60 side in the range of 100 to 500 nm from the first electrode side in the thickness direction of the piezoelectric layer 70. The crystal structure of the crystal system, the monoclinic system, the tetragonal system, the monoclinic system, the rhombohedral system, and the monoclinic system changes continuously. In the rhombohedral part (near 100 to 140 nm from the first electrode side and around 240 to 470 nm from the first electrode side), the rhombohedral system from the range of monoclinic system of Ti / (Ti + Zr)% Fluctuations, that is, X _R which is Ti / (Ti + Zr)% at the boundary between the rhombohedral system and the monoclinic system, and X ₁ and X which are Ti / (Ti + Zr)% at the rhombohedral part The difference from ₂ mag is within 10%. Further, in the tetragonal part (around 150 to 190 nm from the first electrode side), the variation of the tetragonal system from the range of the monoclinic system of Ti / (Ti + Zr)%, that is, the tetragonal system and the monoclinic system. the difference between the Ti / (Ti + Zr)% a is X _T and the portion of the tetragonal Ti / (Ti + Zr)% a is X ₃ or the like in the boundary between the crystal system is within 10%.

  By adopting a crystal structure in such a predetermined range, it is possible to obtain a large displacement with a lower driving voltage than a piezoelectric element having a piezoelectric layer outside the range, that is, to improve the displacement characteristics. It becomes a piezoelectric element that can be used.

  Here, with the change of Ti / (Ti + Zr)%, the crystal structure of the piezoelectric layer 70 changes in a tetragonal system, a monoclinic system, and a rhombohedral system. For example, when Ti / (Ti + Zr)% is relatively low, a rhombohedral system is formed, and as it is higher, a monoclinic system and a tetragonal system are formed. The difference in crystal structure due to the difference in Ti / (Ti + Zr)% is not defined by absolute Ti / (Ti + Zr)%, and the first electrode 60, the insulator film 55, and the elastic film 50 are not limited. Also, it varies depending on the stress due to the base of the piezoelectric layer 70 such as the flow path forming substrate 10 and the manufacturing conditions of the piezoelectric layer 70. The piezoelectric element 300 is manufactured by changing the manufacturing conditions such as the material, thickness, and firing temperature of the base of the first electrode 60 and the like and the piezoelectric layer 70, the crystal structure of each piezoelectric layer 70 is measured, and Ti / Zr + Ti A diagram showing the crystal structure with respect to% is shown in FIG. In the figure, Tet indicates tetragonal system, Mono indicates monoclinic system, and Rhom indicates rhombohedral system. As shown in FIG. 6, even in the piezoelectric layer 70 having the same Ti / Zr + Ti%, the crystal structure is different. That is, the crystal structure is changed not only by Ti / Zr + Ti% but also by stress. Further, for example, when the stress of the piezoelectric layer 70 in FIG. 3 changes, it shifts in the vertical axis direction, that is, the crystal structure changes even with the same Ti / Zr + Ti%.

  Accordingly, even if only the Ti / Zr ratio is specified as in the prior art, the piezoelectric element 300 with good displacement characteristics cannot be obtained with certainty. However, in the present invention, as described above, the influence of stress or the like is also exerted. Since the crystal structure is defined within a predetermined range in consideration, the piezoelectric element 300 having good displacement characteristics can be obtained with certainty.

  In particular, the piezoelectric layer 70 having a thin film thickness of about 1 to 2 μm is subjected to a greater stress than a thick film, so that it is difficult to obtain good displacement characteristics even if only the Ti / Zr ratio is defined. Therefore, the piezoelectric element 300 having good displacement characteristics is obtained.

The method of forming the piezoelectric element 300 having such a piezoelectric layer 70 on the flow path forming substrate 10 is not particularly limited, and can be manufactured by the following method, for example. 7 to 10 are cross-sectional views in the longitudinal direction of the pressure generating chamber showing the method of manufacturing the ink jet recording head according to the first embodiment of the present invention. First, as shown in FIG. 7A, a silicon dioxide film 51 made of silicon dioxide (SiO ₂ ) or the like constituting the elastic film 50 is formed on the surface of a flow path forming substrate wafer 110 that is a silicon wafer. Next, as shown in FIG. 7B, an insulator film 55 made of zirconium oxide or the like is formed on the elastic film 50 (silicon dioxide film 51). Next, as shown in FIG. 7C, a single layer of platinum (Pt) or a first electrode 60 in which an iridium (Ir) layer is laminated and alloyed on the platinum layer is formed by sputtering or the like.

  Next, as shown in FIG. 8A, a seed titanium layer 61 made of titanium (Ti), for example, having a thickness of about 4 nm is formed on the first electrode 60 by a sputtering method or the like. By providing the seed titanium layer 61 on the first electrode 60 in this way, the piezoelectric layer 70 is formed when the piezoelectric layer 70 is formed on the first electrode 60 via the seed titanium layer 61 in a later step. Can be controlled to (100) or (111), and a piezoelectric layer 70 suitable as an electromechanical transducer can be obtained. The seed titanium layer 61 functions as a seed for promoting crystallization when the piezoelectric layer 70 is crystallized, and diffuses into the piezoelectric layer 70 after the piezoelectric layer 70 is fired.

  Next, the piezoelectric layer 70 is formed. Here, in the present embodiment, a so-called sol-gel in which a so-called sol obtained by dissolving and dispersing a metal organic substance in a solvent is applied, dried, gelled, and further fired at a high temperature to obtain a piezoelectric layer 70 made of metal oxide. The piezoelectric layer 70 is formed using the method. The manufacturing method of the piezoelectric layer 70 is not limited to the sol-gel method, and a MOD (Metal-Organic Decomposition) method may be used.

As a specific forming procedure of the piezoelectric layer 70, first, as shown in FIG. 8B, a piezoelectric precursor that is a precursor film of the piezoelectric layer on the first electrode 60 (seed titanium layer 61). A film 74 is formed. That is, a sol (solution) containing Ti and Zr is applied onto the flow path forming substrate 10 on which the first electrode 60 is formed (application process). Next, the piezoelectric precursor film 74 is heated to a predetermined temperature and dried for a predetermined time (drying step). For example, the piezoelectric precursor film 74 can be dried by holding at 150 to 170 ° C. for 5 to 10 minutes. Next, the dried piezoelectric precursor film 74 is degreased by heating it to a predetermined temperature and holding it for a certain time (degreasing step). For example, the piezoelectric precursor film 74 can be degreased by heating to a temperature of about 300 to 400 ° C. and holding for about 5 to 10 minutes. The degreasing referred to here is to release organic components contained in the piezoelectric precursor film 74 as, for example, NO ₂ , CO ₂ , H ₂ O or the like. In the degreasing step, the rate of temperature rise can be set to 15 ° C./sec or more.

  Next, as shown in FIG. 8C, the piezoelectric precursor film 74 is crystallized by heating to a predetermined temperature and holding for a certain period of time to form a first piezoelectric film 75 (firing step). ). For example, the piezoelectric film 75 can be formed by heating the piezoelectric precursor film 74 at 650 to 800 ° C. for 5 to 30 minutes. In the firing step, the temperature increase rate can be set to 15 ° C./sec or less.

  Next, as shown in FIG. 9A, when the first piezoelectric film 75 is formed on the first electrode 60, the first electrode 60 and the first piezoelectric film 75 are simultaneously patterned. .

  Next, as shown in FIG. 9B, the intermediate titanium layer 62 made of titanium (Ti) is formed again on the entire surface of the flow path forming substrate wafer 110 including the first piezoelectric film 75, and then the above-mentioned. By performing the piezoelectric film forming process including the coating process, the drying process, the degreasing process, and the baking process, a second piezoelectric film 75 is formed as shown in FIG. Then, as shown in FIG. 9 (d), by repeatedly performing the piezoelectric film forming process including the coating process, the drying process, the degreasing process, and the baking process described above on the second piezoelectric film 75. A piezoelectric layer 70 composed of a plurality of piezoelectric films 75 is formed.

  Next, as shown in FIG. 10A, after forming the second electrode 80 made of, for example, iridium (Ir) over the piezoelectric layer 70, as shown in FIG. The piezoelectric layer 300 and the second electrode 80 are patterned in a region facing each pressure generating chamber 12 to form the piezoelectric element 300.

  It should be noted that the stress applied to the piezoelectric layer 70 that affects the crystal structure of the piezoelectric layer 70 is the first electrode 60, the insulator film 55, the elasticity in the method of forming the piezoelectric element 300 on the flow path forming substrate 10. The film 50, the base of the piezoelectric layer 70 such as the flow path forming substrate 10 and the manufacturing conditions such as the material, thickness, composition, and firing temperature of the piezoelectric layer 70, and the balance thereof vary.

Example 1
The piezoelectric element 300 was produced on the flow path forming substrate 10 by the method described above. In the step of forming the piezoelectric layer 70, the firing temperature was 680 ° C. In addition, a 12-layer piezoelectric precursor film was formed using the same sol, but the first-layer piezoelectric precursor film was formed and then fired to laminate the second-fourth piezoelectric precursor films. After firing, the piezoelectric precursor films of the 5th to 12th layers were laminated and then fired.
For the piezoelectric layer 70 of the obtained piezoelectric element 300, the crystal structure is measured in the thickness direction by the EELS method, and in the measurement result, the horizontal axis is the distance from the first electrode 60, and the vertical axis is Ti / (Ti + Zr)%. The results are shown in FIG. In the figure, the region indicated by 1L that is partitioned by a broken line is the first layer of the piezoelectric film 75, the region indicated by 2-4L is the region indicated by 2L-4th, and the region indicated by 5L- Indicates the fifth and subsequent layers. Further, the amount of displacement was measured by driving the piezoelectric element.

(Example 2)
The same operation as in Example 1 was performed except that the intermediate titanium layer 62 was not formed. The results are shown in FIG.

(Comparative Example 1)
The same operation as in Example 1 was performed except that the firing temperature of the piezoelectric layer 70 was set to 700 ° C. The results are shown in FIG.

(Comparative Example 2)
The same operation as in Example 1 was performed except that the firing temperature of the piezoelectric layer 70 was 780 ° C. The results are shown in FIG.

(Comparative Example 3)
The same operation as in Example 1 was performed, except that the first electrode 60 was a laminate of platinum (Pt) and titanium (Ti), the film thickness was 80 nm and 50 nm, respectively, and the stress state was changed. The results are shown in FIG.

  As shown in FIGS. 11 to 15, since the stress and the like change when the firing conditions and the base of the piezoelectric layer 70 are changed, the crystal structure of the piezoelectric layer 70 is different between Examples 1-2 and Comparative Examples 1-3. . Then, as shown in FIGS. 11 and 12, the rhombohedral system has a crystal structure within a predetermined range, that is, a monoclinic structure, and a range of Ti / (Ti + Zr)% that is monoclinic. Examples 1-2 in which the variation to the tetragonal system from the range of the monoclinic system is within 10% is as described above with reference to FIGS. Compared with Comparative Examples 1 to 3 having a crystal structure outside the predetermined range, a large amount of displacement could be obtained.

  Further, each second electrode 80 which is an individual electrode of the piezoelectric element 300 is drawn from the vicinity of the end on the ink supply path 14 side and extended to the insulator film 55, for example, gold (Au) or the like. The lead electrode 90 which consists of is connected.

  On the flow path forming substrate 10 on which such a piezoelectric element 300 is formed, that is, on the first electrode 60, the insulator film 55, and the lead electrode 90, there is a reservoir portion 31 that constitutes at least a part of the reservoir 100. The protective substrate 30 is bonded via an adhesive 35. In the present embodiment, the reservoir portion 31 is formed through the protective substrate 30 in the thickness direction and across the width direction of the pressure generation chamber 12. As described above, the communication portion 13 of the flow path forming substrate 10. The reservoir 100 is configured as a common ink chamber for the pressure generation chambers 12. Alternatively, the communication portion 13 of the flow path forming substrate 10 may be divided into a plurality of pressure generation chambers 12 and only the reservoir portion 31 may be used as the reservoir. Further, for example, only the pressure generation chamber 12 is provided in the flow path forming substrate 10, and a reservoir and a member interposed between the flow path forming substrate 10 and the protective substrate 30 (for example, the elastic film 50, the insulator film 55, etc.) An ink supply path 14 that communicates with each pressure generating chamber 12 may be provided.

  A piezoelectric element holding portion 32 having a space that does not hinder the movement of the piezoelectric element 300 is provided in a region of the protective substrate 30 that faces the piezoelectric element 300. The piezoelectric element holding part 32 only needs to have a space that does not hinder the movement of the piezoelectric element 300, and the space may be sealed or unsealed.

  As such a protective substrate 30, it is preferable to use substantially the same material as the coefficient of thermal expansion of the flow path forming substrate 10, for example, glass, ceramic material, etc. In this embodiment, the same material as the flow path forming substrate 10 is used. The silicon single crystal substrate was used.

  The protective substrate 30 is provided with a through hole 33 that penetrates the protective substrate 30 in the thickness direction. The vicinity of the end portion of the lead electrode 90 drawn from each piezoelectric element 300 is provided so as to be exposed in the through hole 33.

  A drive circuit 120 for driving the piezoelectric elements 300 arranged in parallel is fixed on the protective substrate 30. For example, a circuit board or a semiconductor integrated circuit (IC) can be used as the drive circuit 120. The drive circuit 120 and the lead electrode 90 are electrically connected via a connection wiring 121 made of a conductive wire such as a bonding wire.

  In addition, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded onto the protective substrate 30. Here, the sealing film 41 is made of a material having low rigidity and flexibility, and one surface of the reservoir portion 31 is sealed by the sealing film 41. The fixing plate 42 is formed of a relatively hard material. Since the region of the fixing plate 42 facing the reservoir 100 is an opening 43 that is completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with a flexible sealing film 41. Has been.

  In such an ink jet recording head of this embodiment, ink is taken in from an ink introduction port connected to an external ink supply means (not shown), and the interior from the reservoir 100 to the nozzle opening 21 is filled with ink. In accordance with a recording signal from 120, a voltage is applied between each of the first electrode 60 and the second electrode 80 corresponding to the pressure generating chamber 12, and the elastic film 50, the insulator film 55, the first electrode 60, and the piezoelectric body. By bending and deforming the layer 70, the pressure in each pressure generation chamber 12 is increased, and ink droplets are ejected from the nozzle openings 21.

(Other embodiments)
As mentioned above, although one Embodiment of this invention was described, the fundamental structure of this invention is not limited to what was mentioned above. For example, in Embodiment 1 described above, the piezoelectric layer 70 has both the rhombohedral and tetragonal crystal structures in the predetermined range in the range of 100 to 500 nm from the first electrode 60 (FIG. 3). ) And those having the rhombohedral system in the above predetermined range but not having the tetragonal system (Example 2), the present invention is not limited to the rhombohedral system from the range of monoclinic system. The variation of Ti / (Ti + Zr)% and the variation of tetragonal Ti / (Ti + Zr)% from the range of monoclinic system may be within 10%, respectively, and the rhombohedral system and tetragonal system It is not necessary to have both crystal structures. The piezoelectric layer may be preferentially oriented in any of the (100) plane, (110) plane, (001) plane, and (111) plane. In addition, since the orientation is easily controlled when the crystal structure of the piezoelectric layer is a tetragonal system, the crystal structure on the first electrode 60 side of the piezoelectric layer 70 is preferably a tetragonal system.

  For example, in Embodiment 1 described above, a silicon single crystal substrate is exemplified as the flow path forming substrate 10, but the present invention is not particularly limited thereto. For example, the crystal plane orientation is (100) plane, (110) plane, etc. A silicon single crystal substrate may be used, or a material such as an SOI substrate or glass may be used.

  Further, these ink jet recording heads I constitute a part of a recording head unit having an ink flow path communicating with an ink cartridge or the like, and are mounted on the ink jet recording apparatus. FIG. 16 is a schematic view showing an example of the ink jet recording apparatus.

  In the ink jet recording apparatus II shown in FIG. 16, the recording head units 1A and 1B having the ink jet recording head I are detachably provided with cartridges 2A and 2B constituting the ink supply means, and the recording head units 1A and 1B. Is mounted on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. The recording head units 1A and 1B, for example, are configured to eject a black ink composition and a color ink composition, respectively.

  The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted is moved along the carriage shaft 5. The On the other hand, the apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S which is a recording medium such as paper fed by a paper feed roller (not shown) is wound around the platen 8. It is designed to be transported.

  In the first embodiment described above, an ink jet recording head has been described as an example of a liquid ejecting head. However, the present invention is widely intended for all liquid ejecting heads, and is a liquid ejecting a liquid other than ink. Of course, the present invention can also be applied to an ejection head. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

  The present invention is not limited to a piezoelectric element mounted on a liquid jet head typified by an ink jet recording head, and can also be applied to a piezoelectric element mounted on another apparatus.

  I ink jet recording head (liquid ejecting head), II ink jet recording apparatus (liquid ejecting apparatus), 10 flow path forming substrate, 12 pressure generating chamber, 13 communicating portion, 14 ink supply path, 15 communicating path, 20 nozzle plate, 21 nozzle opening, 30 protective substrate, 31 reservoir section, 40 compliance substrate, 50 elastic film, 55 insulator film, 60 first electrode, 70 piezoelectric layer, 80 second electrode, 90 lead electrode, 100 reservoir, 120 drive circuit 300 Piezoelectric element.

Claims (6)

A pressure generation chamber communicating with a nozzle opening for ejecting liquid; and a piezoelectric element that causes a pressure change in the pressure generation chamber,
The piezoelectric element is formed on the opposite side of the first electrode, the piezoelectric layer formed on the first electrode containing titanium (Ti) and zirconium (Zr), and the first electrode of the piezoelectric layer. A liquid ejecting head including the second electrode,
The crystal structure of the piezoelectric layer measured by electron energy loss spectroscopy in the thickness direction in the range of 100 to 500 nm from the first electrode has a monoclinic structure portion, and the horizontal axis of the measurement results When the distance from the first electrode and the vertical axis is Ti / (Ti + Zr)%, the variation of Ti / (Ti + Zr)% from the monoclinic range to the rhombohedral system is within 10%. In addition, the liquid ejecting head is characterized in that a change from a monoclinic system to a tetragonal system is within 10%.   The liquid ejecting head according to claim 1, wherein a crystal structure of the piezoelectric layer is different in a thickness direction of the piezoelectric layer.   The liquid jet head according to claim 1, wherein the piezoelectric layer has a thickness of 1 to 2 μm.   The liquid ejecting head according to claim 1, wherein the first electrode includes platinum.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1. A first electrode; a piezoelectric layer formed on the first electrode and containing titanium (Ti) and zirconium (Zr); and a second electrode formed on the opposite side of the piezoelectric layer from the first electrode. And
The crystal structure of the piezoelectric layer measured by electron energy loss spectroscopy in the thickness direction in the range of 100 to 500 nm from the first electrode has a monoclinic structure portion, and the horizontal axis of the measurement results When the distance from the first electrode and the vertical axis is Ti / (Ti + Zr)%, the variation of Ti / (Ti + Zr)% from the monoclinic range to the rhombohedral system is within 10%. And an actuator device characterized in that a change from a monoclinic system to a tetragonal system is within 10%.

Images