JP2013163361A - Method of evaluating piezoelectric element, piezoelectric element, and liquid ejection head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric element evaluation method, a piezoelectric element and a liquid jet head capable of evaluating deformation efficiency more easily and accurately.
A method of evaluating a piezoelectric element provided on a pressure generating chamber 12 via a diaphragm 55, wherein the direction in which the piezoelectric elements are arranged side by side is a first direction, and a direction perpendicular to the first direction is a first direction. The length of the piezoelectric active portion 320 of the piezoelectric element in the first direction is a (μm), the length in the second direction is b (μm), and the first direction of the pressure generating chamber is two directions. The length in the second direction is c (μm), the length in the second direction is d (μm), and the values of (b / c), (a / c), and [(b−c + 100) / d] are calculated as parameters. And evaluate the deformation efficiency.
[Selection] Figure 5

Description

  The present invention relates to a method for evaluating a piezoelectric element provided on a pressure generating chamber via a diaphragm, a piezoelectric element, and a liquid ejecting head.

  Conventionally, a piezoelectric element is known as an electromechanical conversion element. The piezoelectric element is usually composed of a lower electrode and an upper electrode and a piezoelectric layer sandwiched between these electrodes, and is formed on the pressure generating chamber via a diaphragm, and applies a voltage to the lower electrode and the upper electrode. It is driven by that. An actuator is composed of such a piezoelectric element and a diaphragm. The actuator is said to have better electromechanical conversion efficiency, that is, better performance as an actuator, as the amount of deformation due to deformation of the diaphragm is larger for the same applied voltage.

  Japanese Patent Application Laid-Open No. 2004-228561 describes a technique for adjusting the length in the short direction and the length in the short direction of the pressure generating chamber to reduce the variation in the deformation amount of the diaphragm caused by driving the piezoelectric element. .

JP 2004-066496 A

  However, the evaluation method disclosed in Patent Document 1 cannot accurately evaluate the actuator, and further improvement in accuracy is required.

  Therefore, an object of the present invention is to provide a piezoelectric element evaluation method, a piezoelectric element, and a liquid ejecting head that can evaluate deformation efficiency more easily and accurately.

The present invention for solving the above-mentioned problems is a method for evaluating a piezoelectric element provided on a pressure generating chamber via a diaphragm, wherein the direction in which the piezoelectric elements are arranged side by side is a first direction and is orthogonal to the first direction. The direction is the second direction, and the length of the piezoelectric active part of the piezoelectric element in the first direction is a (μm), the length of the second direction is b (μm) in plan view, The length in one direction is c (μm), the length in the second direction is d (μm), and the values of (b / c), (a / c), and [(b−c + 100) / d] are parameters. And evaluating the deformation efficiency in the piezoelectric element evaluation method.
According to this, by using the values of (b / c), (a / c), and [(b−c + 100) / d] as parameters, the deformation efficiency can be more easily and accurately evaluated. .

  Here, it is preferable to evaluate the deformation efficiency by multiplying the deformation efficiency calculated by the values of (b / c), (a / c), and [(b−c + 100) / d]. According to this, the deformation efficiency of the whole piezoelectric element can be evaluated more easily and more accurately.

  The (b / c) is 3.0 ≦ (b / c) ≦ 5.0, the (a / c) is 0.70 ≦ a / c ≦ 0.90, and the [(b−c + 100 ) / D] is preferably in the range of 1.0 ≦ [(b−c + 100) / d] ≦ 1.2. According to this, a piezoelectric element with suitable deformation efficiency can be designed.

Another aspect of the present invention is a piezoelectric element provided on a pressure generation chamber via a diaphragm, wherein the direction in which the piezoelectric elements are arranged side by side is a first direction, and a direction orthogonal to the second direction is a second direction. The length of the piezoelectric active part of the piezoelectric element in the first direction is a (μm), the length of the second direction is b (μm), and the length of the pressure generating chamber in the first direction in plan view. When the thickness is c (μm) and the length in the second direction is d (μm), 3.0 ≦ (b / c) ≦ 5.0, 0.70 ≦ a / c ≦ 0.90, The piezoelectric element is characterized by satisfying the condition of 0 ≦ [(b−c + 100) / d] ≦ 1.2.
According to the present invention, a piezoelectric element with high deformation efficiency can be realized.

Another aspect of the invention is a liquid ejecting head including the piezoelectric element.
According to the present invention, a liquid ejecting head having good ejection characteristics can be realized.

FIG. 3 is an exploded perspective view illustrating a schematic configuration of the recording head according to the first embodiment. FIG. 3 is a plan view of the recording head according to the first embodiment. FIG. 3 is a cross-sectional view of the recording head according to the first embodiment. The top view explaining the conditions of simulation. Sectional drawing of FIG. The figure which shows a simulation result. The figure which shows a simulation result. The figure which shows a simulation result. 1 is a diagram illustrating a schematic configuration of a recording apparatus according to an embodiment of the present invention.

(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 invention, FIG. 2 is a plan view of FIG. 1, and FIG. 2 is a cross-sectional view taken along line AA ′ of FIG. As shown in FIGS. 1 to 3, the flow path forming substrate 10 of the present embodiment is made of a silicon single crystal substrate, and an elastic film 50 made of silicon dioxide 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 manifold part 31 of a protective substrate, which will be described later, and constitutes a part of a manifold that becomes a common ink chamber for each pressure generating chamber 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 14 may be formed by narrowing the width of the flow path from both sides. Further, the ink supply path 14 may be formed not by narrowing the width of the flow path but by narrowing from the thickness direction. In the present 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. On the elastic film 50, for example, titanium oxide having a thickness of about 30 to 50 nm or the like. An adhesion layer 56 for improving adhesion between the first electrode 60 such as the elastic film 50 and the like is provided. The adhesion layer 56 is not necessarily provided, and an insulator film made of zirconium oxide or the like may be provided on the elastic film 50 as necessary.

  Further, a first electrode 60, a piezoelectric layer 70, which is a thin film having a thickness of 620 nm to 1520 nm, and a second electrode 80 are stacked on the adhesion layer 56, and pressure is applied to the pressure generating chamber 12. A piezoelectric element 300 is configured as pressure generating means for causing a change. 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. Here, a portion where piezoelectric distortion occurs due to application of voltage to both electrodes is referred to as a piezoelectric active portion 320, which is continuous from the piezoelectric active portion 320 but is not sandwiched between the first electrode 60 and the second electrode 80, The portion that is not voltage-driven is called a piezoelectric inactive portion. Also, the piezoelectric element 300 and a diaphragm that is deformed by driving the piezoelectric element 300 are collectively referred to as a piezoelectric element or an actuator device. In the above-described example, the elastic film 50, the adhesion layer 56, the first electrode 60, and the insulator film provided as necessary function as a vibration plate. However, the present invention is not limited to this. For example, the elastic film 50 and the adhesion layer 56 may not be provided. Further, the piezoelectric element 300 itself may substantially serve as a diaphragm, and in this case, the whole is also referred to as a piezoelectric element.

  In the present embodiment, the piezoelectric material constituting the piezoelectric layer 70 is a composite oxide having a perovskite structure, for example, a composite oxide having at least Pb, Ti and Zr and having a perovskite structure. It is. Specifically, for example, lead zirconate titanate (PZT) or a relaxor ferroelectric material in which a metal such as niobium, nickel, magnesium, bismuth or yttrium is added thereto is used. The piezoelectric layer 70 of this embodiment is made of lead zirconate titanate (PZT).

  In particular, in order to suppress the content of non-lead or lead and reduce the burden on the environment, it has a perovskite structure containing bismuth (Bi), iron (Fe), barium (Ba) and titanium (Ti). A composite oxide may be used. Such a composite oxide containing Bi, Fe, Ba, and Ti and having a perovskite structure is a composite oxide having a perovskite structure of a mixed crystal of bismuth ferrate and barium titanate, or bismuth ferrate and barium titanate. Is also expressed as a solid solution in which the solid solution is uniformly dissolved.

  Each of the second electrodes 80, which are individual electrodes of the piezoelectric element 300, is drawn from the vicinity of the end on the ink supply path 14 side to the elastic film 50 or an insulator film provided as necessary. An extended lead electrode 90 made of, for example, gold (Au) or the like is connected.

  At least a part of the manifold 100 is formed on the flow path forming substrate 10 on which such a piezoelectric element 300 is formed, that is, on the first electrode 60, the elastic film 50, the insulator film provided as necessary, and the lead electrode 90. A protective substrate 30 having a manifold portion 31 constituting the above is joined via an adhesive 35. In this embodiment, the manifold portion 31 penetrates the protective substrate 30 in the thickness direction and is formed across the width direction of the pressure generating chamber 12. As described above, the communication portion 13 of the flow path forming substrate 10. The manifold 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 manifold portion 31 may be used as a manifold. Further, for example, only the pressure generation chamber 12 is provided in the flow path forming substrate 10 and a member (for example, an elastic film 50, an insulator film provided as necessary, etc.) interposed between the flow path forming substrate 10 and the protective substrate 30 ) May be provided with an ink supply path 14 for communicating the manifold 100 and each pressure generating chamber 12.

  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 manifold portion 31 is sealed by the sealing film 41. The fixing plate 42 is formed of a relatively hard material. Since the area of the fixing plate 42 facing the manifold 100 is an opening 43 that is completely removed in the thickness direction, one surface of the manifold 100 is sealed only with a flexible sealing film 41. Has been.

  In such an ink jet recording head I 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 manifold 100 to the nozzle opening 21 is filled with ink, and then driven. In accordance with a recording signal from the circuit 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 adhesion layer 56, 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.

  In the case of designing such an ink jet recording head I or a piezoelectric element mounted thereon, the present invention maintains the displacement efficiency of the piezoelectric element within a good range, and the dimensions of the pressure generating chamber 12 and the piezoelectric element. The present invention relates to an evaluation method capable of simply designing the dimensions of the piezoelectric active portion 320 of the element 300.

  Hereinafter, a method for evaluating a piezoelectric element according to an embodiment of the present invention will be described with reference to the drawings.

  4 to 5 are schematic diagrams of the piezoelectric element used in the simulation performed in the present embodiment. 4 is a plan view of FIG. 3. FIG. 4A shows a case where the pressure generating chamber 12 and the piezoelectric active portion 320 are rectangular, and FIG. 4B shows a case where the pressure generating chamber 12 and the piezoelectric active portion 320 are rectangular. Are parallelograms, and FIGS. 5A and 5B are cross-sectional views taken along the line BB ′ and the line CC ′ of FIG. A drawing for explaining FIG. 4B is omitted. FIG. 5 schematically shows the diaphragm 55 mainly made of the elastic film 50 in the embodiment described above.

  When the direction in which the piezoelectric elements are arranged side by side is the first direction, and the direction orthogonal thereto is the second direction, the length in the first direction (BB ′ line direction) of the piezoelectric active part 320 in plan view A (μm), the length in the second direction (CC ′ line direction) is b (μm), and the length of the pressure generating chamber 12 in the first direction (BB line direction) is c (μm). The length in the second direction (CC ′ line direction) is d (μm), and the values of (b / c), (a / c), and [(b−c + 100) / d] are used as parameters, FIG. 6 shows the relationship between the value of (b / c) and the deformation efficiency, and FIG. 7 shows the relationship between the value of (a / c) and the deformation efficiency. FIG. 8 shows the relationship between the value of [(b−c + 100) / d] and the deformation efficiency. 6 and 7, the pressure generation chamber 12 and the piezoelectric active part 320 are rectangular and parallelograms, but there is almost no difference between them. Simulation was performed only in the case of.

  The simulation was performed by the finite element method, and was calculated by calculating the deformation amount of the diaphragm and the volume change (excluded volume) of the pressure generation chamber by driving the piezoelectric element.

  The simulated ranges are 34 ≦ c ≦ 70 (μm), 0.10 ≦ (a / c) ≦ 1.0, 1.0 ≦ (b / c) ≦ 5.0, 0.0 <[( b−c + 100) / d] ≦ 1.2.

  Further, when there is a protective film from the diaphragm 55, when the thickness of the entire piezoelectric element 300 including the protective film is e and the thickness of the piezoelectric layer 70 of the piezoelectric active part 320 is f, 0.37 ≦ ( f / e) ≦ 1.0, and the deformation amount δ of the piezoelectric layer 70 was simulated in a range of 0.030 ≦ δ ≦ 1.0 (μm).

  The deformation efficiency evaluated in the present embodiment corresponds to the excluded volume (%) by converting the deformation amount δ of the diaphragm into the deformation efficiency.

  FIG. 6 shows the relationship between the ratio (b / c) between the length b in the second direction of the piezoelectric active part 320 and the length c in the first direction of the pressure generating chamber 12 and the deformation efficiency (%). .

  From FIG. 6, the deformation efficiency decreases as (b / c) decreases, and the deformation efficiency of the actuator is maximum in the range of (b / c) ≧ 3.0, preferably (b / c) ≧ 4.0. That is, it turns out that it becomes about 100%. In addition, it is known from the realistic dimension regulation that (b / c) is preferably 20 or less.

  FIG. 7 shows the relationship between the ratio (a / c) between the length a in the first direction of the piezoelectric active part 320 and the length c in the first direction of the pressure generating chamber 12 and the deformation efficiency (%). Show.

  From FIG. 7, in the range of 0.70 ≦ a / c ≦ 0.90, preferably 0.70 ≦ a / c ≦ 0.85, the deformation efficiency of the actuator is maximum, that is, about 100%, It turns out that deformation efficiency falls, so that it remove | deviates from this range.

  FIG. 8 shows the relationship between the predetermined value [(b−c + 100) / d] relating to the length b of the piezoelectric active part 320 in the second direction and the length c of the pressure generating chamber 12 in the first direction, and the deformation efficiency. Indicates.

  FIG. 8 shows that the deformation efficiency of the actuator is maximum, that is, about 100% in the range of [(b−c + 100) / d] ≧ 1.0. In addition, it has been found that [(b−c + 100) / d] is preferably 2.0 or less from realistic dimensional regulations.

  Here, the deformation efficiency of [(b−c + 100) / d] is different in meaning from the deformation efficiency defined by a / c and b / c. The excluded volume is defined as a length b (μm) in the second direction (C-C ′ line direction) of the piezoelectric active part 320 and a length c (in the BB ′ line direction) of the pressure generating chamber 12. The ratio of (b−c + 100) corrected by (μm) to the length d (μm) of the pressure generation chamber 12 in the second direction (CC ′ line direction) is [(b−c + 100) / d] <1 In this case, the length b (μm) in the second direction (CC ′ line direction) of the piezoelectric active portion 320 is set to the length c (μm) in the first direction (BB line direction) of the pressure generating chamber 12. ) Corrected by (b−c + 100), and is proportional to the product of the length c (μm) of the pressure generation chamber 12 in the first direction (BB ′ line direction) and the deformation amount δ. On the other hand, when [(b−c + 100) / d] ≧ 1, the excluded volume is proportional to the product of the length c (μm) of the pressure generation chamber 12 in the first direction (B-B ′ line direction) and the deformation amount δ. However, the length b (μm) in the second direction (CC ′ line direction) of the piezoelectric active portion 320 is set to the length c (μm) in the first direction (BB line direction) of the pressure generating chamber 12. ) Is not proportional to (b−c + 100) corrected in (1). The deformation efficiency of [(b−c + 100) / d] is due to the length d (μm) of the pressure generation chamber 12 in the second direction (CC ′ line direction), and although not shown, actually contributes to the deformation. The ratio b ′ / d of the length b ′ (μm) in the second direction (CC ′ line direction) of the piezoelectric active portion 320 is simply and accurately evaluating the optimal range of deformation efficiency. It is important as a parameter that can be

  As a result, from the relationship between the values of (b / c), (a / c), and [(b−c + 100) / d] and the deformation efficiency, the dimensions a to d that can be designed are taken into consideration. Since the deformation efficiency for each value of d can be easily evaluated, a design range that meets the design conditions and has good deformation efficiency can be easily evaluated.

  For example, when the dimension c in the first direction of the pressure generation chamber 12 is 34 μm, the dimension d in the second direction of the pressure generation chamber 12, the dimension a in the first direction of the piezoelectric active part 320, and the dimension b in the second direction. The preferred range is as follows.

24 ≦ a ≦ 29 (μm) (0.70 ≦ a / c ≦ 0.85)
140 ≦ b ≦ 170 (μm) (4.0 ≦ b / c ≦ 5.0)
172 ≦ d ≦ 236 (μm) (1.0 ≦ [(b−c + 100) / d] ≦ 1.2)

  For example, when the dimension c of the pressure generation chamber 12 in the first direction c = 70 μm, the following range is the optimum range.

49 ≦ a ≦ 60 (μm) (0.70 ≦ a / c ≦ 0.85)
280 ≦ b ≦ 350 (μm) (4.0 ≦ b / c ≦ 5.0)
258 ≦ d ≦ 380 (μm) (1.0 ≦ [(b−c + 100) / d] ≦ 1.2)

  In the piezoelectric element of the above-described embodiment, the length in the first direction (BB ′ line direction) of the piezoelectric active portion 320 satisfying such an optimal range is a (μm), and the second direction (C− The length in the C ′ line direction) is b (μm), the length in the first direction (BB ′ line direction) of the pressure generating chamber 12 is c (μm), and the second direction (CC ′ line direction). Is the length d (μm).

  Note that the deformation efficiency of the actuator may be evaluated from the relationship between the deformation efficiency and each of the values (b / c), (a / c), and [(b−c + 100) / d]. However, for example, the product of all parameters may be used as the evaluation parameter, and the evaluation method is not particularly limited.

  In the above example, the pressure generation chamber and the piezoelectric active part were simulated as a rectangle or a parallelogram, but the same applies to the ellipse, the ellipse, the track shape of the track and field, etc. It is clear from the simulation results on the parallelogram.

  In the evaluation method of the present invention, when designing the piezoelectric element and the liquid jet head described above, the dimensions of the pressure generating chamber and the piezoelectric electric active part are restricted by the dimensions of each member. Length a (μm) in the first direction (BB ′ line direction) and the second direction (CC ′ line direction) of the piezoelectric active part 320 that can obtain the maximum deformation efficiency due to various restrictions. Length b (μm), length c (μm) in the first direction (BB ′ line direction) of the pressure generating chamber 12, and length d (μm) in the second direction (CC ′ line direction). It is extremely useful as a method for predicting the above with relative ease and high accuracy.

  The ink jet recording head of such an embodiment constitutes a part of a recording head unit including an ink flow path communicating with an ink cartridge or the like, and is mounted on the ink jet recording apparatus. FIG. 9 is a schematic view showing an example of the ink jet recording apparatus.

  In the ink jet recording apparatus II shown in FIG. 9, 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 that 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 above-described embodiment, the ink jet recording head has been described as an example of the liquid ejecting head. However, the present invention is widely applied to all liquid ejecting heads, and the liquid ejecting ejects a liquid other than ink. Of course, it can also be applied to the 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.

  Further, the piezoelectric element according to the present invention is not limited to the piezoelectric element used in the liquid ejecting head, and can be used in other devices. Other devices include, for example, an ultrasonic device such as an ultrasonic transmitter, an ultrasonic motor, a temperature-electric converter, a pressure-electric converter, a ferroelectric transistor, a piezoelectric transformer, and a filter for blocking harmful rays such as infrared rays. And filters such as an optical filter using a photonic crystal effect by quantum dot formation, an optical filter using optical interference of a thin film, and the like. The present invention can also be applied to a piezoelectric element used as a sensor and a piezoelectric element used as a ferroelectric memory. Examples of the sensor using the piezoelectric element include an infrared sensor, an ultrasonic sensor, a thermal sensor, a pressure sensor, a pyroelectric sensor, and a gyro sensor (angular velocity sensor).

  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, 20 nozzle plate, 21 nozzle opening, 30 protective substrate, 31 manifold portion, 32 piezoelectric element holding portion, 40 compliance substrate, 50 elastic film, 60 first electrode, 70 piezoelectric layer, 80 second electrode, 90 lead electrode, 100 manifold, 120 drive circuit, 300 piezoelectric Element, 320 piezoelectric active part

Claims (5)

A method for evaluating a piezoelectric element provided on a pressure generating chamber via a diaphragm, wherein a direction in which the piezoelectric elements are arranged side by side is a first direction, and a direction orthogonal to the direction is a second direction, and is a plan view The length in the first direction of the piezoelectric active portion of the piezoelectric element is a (μm), the length in the second direction is b (μm), and the length in the first direction of the pressure generating chamber is c (μm). ), The length in the second direction is d (μm), and the values of (b / c), (a / c), and [(b−c + 100) / d] are calculated as parameters to evaluate the deformation efficiency. A method for evaluating a piezoelectric element. The deformation efficiency is evaluated by multiplying the deformation efficiency calculated by the values of (b / c), (a / c), and [(b−c + 100) / d]. Evaluation method of piezoelectric element. (B / c) is 3.0 ≦ (b / c) ≦ 5.0, (a / c) is 0.70 ≦ a / c ≦ 0.90, [(b−c + 100) / d] is in the range of 1.0 ≦ [(b−c + 100) / d] ≦ 1.2. 3. The method for evaluating a piezoelectric element according to claim 1, wherein d] is in a range of 1.0 ≦ [(b−c + 100) / d] ≦ 1.2. A piezoelectric element provided on a pressure generating chamber via a vibration plate, wherein a direction in which the piezoelectric elements are arranged side by side is a first direction, and a direction orthogonal to the second direction is a second direction. The length in the first direction of the piezoelectric active part of the piezoelectric element is a (μm), the length in the second direction is b (μm), the length in the first direction of the pressure generating chamber is c (μm), When the length in two directions is d (μm), 3.0 ≦ (b / c) ≦ 5.0, 0.70 ≦ a / c ≦ 0.90, 1.0 ≦ [(b−c + 100) /D]≦1.2, a piezoelectric element that satisfies the condition. A liquid ejecting head comprising the piezoelectric element according to claim 4.

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