JP2000294845A - Droplet ejector - Google Patents

Abstract

(57) [Problem] To provide a droplet ejecting apparatus capable of repolarizing a piezoelectric element with high resolution of droplet ejection. SOLUTION: A piezoelectric element substrate having, on a surface thereof, first and second concave portions for containing a liquid, and a liquid flow path connecting the concave portions, and an inner surface of the first concave portion. An inner electrode formed on a piezoelectric element substrate;
A back electrode formed on the back surface of the piezoelectric element substrate facing the bottom surface of the concave portion, and a droplet ejecting hole at a position corresponding to the first concave portion, wherein the first and second concave portions and the liquid flow path are formed. And a lid mounted on the surface of the piezoelectric element substrate so as to cover the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid droplet ejecting apparatus used for an ink jet printer head or the like.

[0002]

2. Description of the Related Art In recent years, an ink jet printer has attracted attention as an output terminal of a personal computer. The driving method of the ink jet printer head, which can be said to be the heart, is roughly classified into a piezoelectric driving method and a heat driving method. The piezoelectric driving method is superior to the thermal driving method in terms of responsiveness and durability.

A configuration of a conventional piezoelectric drive type ink jet printer head and a method of manufacturing the same are disclosed in, for example, Japanese Patent Application Laid-Open No. 2-150355. FIG.
1 is a cross-sectional view showing a conventional inkjet printer head disclosed in this document. The inkjet printer head of FIG. 12 includes a bottom sheet 314 and a top sheet 320 disposed on top of the bottom sheet 314.
The bottom sheet 314 is located above (in the direction of arrow 315 in the figure)
It is formed from a piezoelectric material that is polarized. Bottom seat 3
A number of mutually parallel grooves 312 are formed in 14. Opposite side surfaces 316 of a substantially upper half of the groove 312
Is formed with an electrode 334. By disposing the top sheet 320 on the top of the bottom sheet 314, each groove 312 is closed to form an ink pressure chamber.
Each ink pressure chamber is provided with a nozzle (not shown) and an ink supply port (not shown), and the ink supply port is connected to an ink supply unit (not shown) via an ink supply pipe (not shown). Have been. The ink filled in the pressure chamber from the ink supply unit is ejected from the nozzle to the outside.

[0004] The ink jet printer head of FIG. 12 operates as follows. Both sides 3 of each groove 312
A voltage having the opposite sign is applied to each of the electrodes 334 formed on the 16. By applying such a voltage, the portion of the piezoelectric body sandwiched between the electrodes 334 receives an electric field orthogonal to the polarization direction (the direction of arrow 315 in the figure). The piezoelectric member that has received the electric field is curved as shown by a dotted line in FIG. As a result, the volume of the ink pressure chamber (groove 312) rapidly decreases, and the pressure in the ink pressure chamber becomes positive. The ink in the ink pressure chamber that has become positive pressure is ejected to the outside through the nozzle.

[0005] The ink jet printer head of FIG. 12 is manufactured as follows. First, a plurality of parallel grooves 312 are provided in a bottom sheet 314 made of a piezoelectric material using a dicing saw. Next, the bottom sheet 314 is held using a jig in a vacuum evaporation apparatus,
A metal material is vacuum-deposited from obliquely above 14. In this manner, the electrode 33 is placed on substantially the upper half of one side
4 are formed. Subsequently, the bottom sheet 314 is rotated 180 degrees, and a metal material is vacuum-deposited in the same manner as described above. In this manner, the electrode 334 is also deposited on substantially the upper half of the other side surface of the groove 312. The electrodes 3 are provided on both sides of the groove 312.
After forming 34, the unnecessary metal deposition film formed on the top 322 of the bottom sheet 314 is removed. Next, the top sheet 320 is bonded to the top of the bottom sheet 314 using an adhesive. Thus, ink pressure chambers are formed, and an ink supply port for connecting an ink supply pipe to each ink pressure chamber is provided, whereby an ink jet printer head is completed.

The ink jet printer head shown in FIG. 12 has the following problems. (1) The groove 312 is formed on the bottom sheet 3 using a dicing saw.
14, the lower limit of the width of the groove 312 is several tens μm. Therefore, the drawing resolution determined by the distance between the ink pressure chambers is several hundreds of dpi (dot per i).
nch) was the upper limit. (2) The groove 312 is formed on the bottom sheet 3 using a dicing saw.
14, it is difficult to form the groove 312 other than the linear shape. Therefore, only an ink jet printer head having a structure in which ink is ejected in parallel with the bottom surface of the bottom sheet 314 can be manufactured. As a result, the number of nozzles is limited to a one-dimensional array, and there is a limit in improving the drawing resolution and the drawing speed. (3) When one ink pressure chamber becomes positive pressure and ink is ejected, the ink pressure chambers on both sides of the ink pressure chamber always become negative pressure. That is, only one ink pressure chamber can be used at a time. Therefore, the actual interval between the ink pressure chambers is twice as large as the actual interval, resulting in a decrease in the drawing resolution. (4) The polarization direction of each piezoelectric body portion sandwiched between the electrodes 334,
The direction of the electric field applied to each piezoelectric body by the electrode 334 is orthogonal to the direction of the electric field. Therefore, when the polarization of each piezoelectric body is depolarized due to a rise in temperature or the like, a voltage cannot be applied between the electrodes 334 to repolarize the piezoelectric body.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a droplet ejecting apparatus which has a high resolution for ejecting a droplet and can repolarize a piezoelectric element.

[0008]

According to the present invention, a piezoelectric element substrate having, on a surface thereof, first and second recesses for accommodating a liquid and a liquid flow path connecting these recesses. An inner electrode formed on the piezoelectric element substrate along the inner surface of the first concave portion, a back electrode formed on the back surface of the piezoelectric element substrate facing the bottom surface of the first concave portion,
And a lid portion mounted on the surface of the piezoelectric element substrate so as to cover the first and second concave portions and the liquid flow path. A droplet ejector is provided.

In the present invention, it is preferable that there are a plurality of the first concave portions, and the first concave portions are one-dimensionally arranged on the surface of the piezoelectric element substrate.

In the present invention, it is preferable that a plurality of the first concave portions are provided, and the first concave portions are two-dimensionally arranged on the surface of the piezoelectric element substrate.

Further, inner electrodes formed along the inner surfaces of the plurality of first recesses are connected by a conductor layer formed on an upper surface of the piezoelectric element substrate, and the back electrode is formed of the plurality of first recesses. It is preferable that they are independently provided at positions corresponding to the bottom surface.

Further, in the present invention, it is preferable that the first and second concave portions are formed by dry-etching the piezoelectric element substrate.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of a droplet ejecting apparatus according to the present invention. FIG. 1A is a schematic perspective view thereof, and FIG.
FIG. 2B is a sectional view taken along line BB ′ in FIG. The droplet ejecting apparatus according to the present invention includes one piezoelectric block 1 and a lid 2 mounted on the surface of the block 1.

The piezoelectric block 1 is usually in the shape of a rectangular parallelepiped or the like. The dimensions of the piezoelectric block material 1 are, for example, about 10 mm in width, about 10 mm in length, and about 0.5 mm in thickness (or height). The piezoelectric block material 1 is not particularly limited as long as it is a piezoelectric ceramic. Examples of the piezoelectric ceramic include lead zirconate titanate (PZT) -based ceramics, lead zinc niobate and lead titanate (PZN-PT) -based ceramics, and lead magnesium niobate and lead titanate (PMN-PT) -based ceramics. No.

The piezoelectric block material 1 is made of, for example, a material obtained by firing the above-mentioned ceramic material powder or a material obtained by grinding or cutting a single crystal such as a solid solution single crystal of the ceramic material. In addition, the piezoelectric block material 1
A material obtained by grinding or cutting out a single crystal is more preferable than a material obtained by firing a material powder. This is because a single crystal has a higher orientation and a higher density than a sintered one and has excellent piezoelectric characteristics.

In one surface of the piezoelectric block 1,
A first concave portion 3 for accommodating a liquid, a second concave portion 4, and a liquid flow channel groove 5 for connecting the first and second concave portions 3 and 4 to each other are formed. In the case of an ink jet printer head, a plurality of first concave portions 3 are provided. The second recess 4 may be further connected to a liquid supply channel groove (not shown). One end of the liquid supply channel groove (not shown) is connected to the second recess 4, and the other end is connected to the side surface of the piezoelectric block 1.

Examples of the liquid include inks used in ink-jet printers, test solutions, and chemicals such as reagents.

The shapes of the first and second concave portions 3 and 4 include a circle and a square, and are not particularly limited. FIG.
1 shows a circular first concave portion 3 and a square second concave portion 4 as examples. The dimensions of the concave portions 3 and 4 and the groove 5 are determined by the use of the liquid droplet ejecting apparatus according to the present invention, for example, the specifications of an ink jet printer head, and are not particularly limited. As an example, the diameter of the circular first recess 3 is about 50 μm and the depth is about 490 μm, and the size of the square second recess 4 is 500 μm in length × 300 μm in width and about 490 μm in depth, Also, the width of the liquid channel groove 5 is about 10 μm.
m, the depth is about 490 μm. Recesses 3, 4 and groove 5
Can be formed on the surface of the piezoelectric block material by selective etching, which is a dry process using plasma of a reactive gas, as described later.

Lid 2 for covering recesses 3 and 4 and groove 5
Is mounted on the surface of the piezoelectric block material 1 in a liquid-tight manner. The lid 2 has, for example, a sheet-like shape. When the lid 2 is a sheet member, the thickness is, for example, about 0.1 mm. The material forming the lid 2 is, for example, a piezoelectric material of the same type as the piezoelectric block material 1 or an insulator such as quartz glass. Further, the lid 2 has a droplet ejection hole 9 at a position corresponding to the first recess 3 for ejecting the liquid stored in the first recess 3 as a droplet to the outside. The diameter of the droplet jetting hole 9 needs to be appropriately changed depending on the diameter of the droplet finally required and the like, and is, for example, 20 μm.

The first and second concave portions 3 and 4 covered by the lid 2 form first and second liquid storage chambers for storing liquid, respectively. The liquid flow channel groove 5 covered by the lid 2 forms a liquid flow channel connecting the first and second liquid storage chambers. In addition, the above-described liquid supply channel groove 5 covered by the lid 2 forms a liquid supply channel that supplies liquid from an external liquid supply source to the second liquid storage chamber.

As shown in FIG. 1B, an inner surface electrode 6 is formed on the inner surface including the bottom surface and the side surface of the first recess 3. The inner surface electrode 6 is connected to a surface wiring electrode 10 continuously formed on the upper surface of the piezoelectric block material 1 to form a common electrode composed of one connected conductor. The surface wiring electrode 10 may be formed not only on the upper surface of the piezoelectric block material 1 but also continuously from the upper surface to the side surface. The electrode portion formed on the side surface of the piezoelectric block 1 is exposed to the outside even when the lid 2 is attached to the piezoelectric block 1. By connecting a wiring or the like from a power supply to the exposed front surface wiring electrode 10, a voltage can be applied to the inner surface electrode 6 from the outside.

The inner surface electrode 6 and the above-mentioned surface wiring electrode 10
A conductive layer may also be formed on portions other than the region where is formed, for example, on the bottom surface and side surfaces of the second concave portion 4, the liquid flow channel groove 5, and the liquid supply channel groove (not shown). . These areas are areas where it is not necessary to form a conductive layer,
Even if the conductive layer is formed, it does not hinder the operation as the droplet ejecting apparatus. FIG. 1B is a cross-sectional view showing an example in which a conductive layer is formed on the bottom surface and the side surface of each of the recesses 3 and 4 and the groove 5.

A back electrode 7 is formed on the back surface of the piezoelectric block 1 so as to face the bottom surface of the first recess 3. The back electrodes 7 are individually formed at positions corresponding to the first concave portions 3. Further, a back wiring electrode (not shown) connected to the back electrode 7 is formed on the back surface of the piezoelectric block material 1. FIG. 2 shows an example of the back electrode 7 and the back wiring electrode. In FIG. 2, a strip-shaped back wiring electrode 11 is connected to each circular back electrode 7.

The material of the conductive layer forming the inner and rear electrodes 6, 7 and the wiring electrodes 10, 11 and the method of forming the conductive layer are not particularly limited. Examples of the material of the conductive layer include a metal material. Examples of the metal material include a single metal such as gold, silver, copper, platinum, titanium, nickel, and chromium, and a laminate of a metal such as chromium / gold that combines these single metals.
Examples of the method of forming the conductive layer include CVD (chemical vapor deposition), electroplating, electroless plating, sputtering, vapor deposition, and ion plating.

The thicknesses of the inner surface and the back electrodes 6, 7 are different from each other. As a specific thickness, for example, one is about 1 to 50 μm and the other is 0.01 mm to 0.1 mm
It is preferable that the thickness is about 1 to 50 μm. As an example, the inner electrode is 1 μm and the back electrode is 10 μm, or the inner electrode is 0.1 mm and the back electrode is 1 μm.
0 μm. Since the thicknesses of the inner surface and the back electrodes 6 and 7 are different, the elasticity of each electrode in the in-plane direction, that is, the amount of elongation and the amount of contraction with respect to a constant stress are different from each other.
The thicker one has less expansion and contraction, and the thinner one has more expansion and contraction.

As shown in FIG. 1B, a piezoelectric element is formed by the inner and rear electrodes 6, 7 and the piezoelectric portion 8 at the bottom of the first concave portion 3 sandwiched between both electrodes. The piezoelectric portion 8 is polarized in the thickness direction, that is, polarized in the direction from the inner electrode 6 to the back electrode 7 or in the opposite direction. In order to polarize the piezoelectric body portion 8, for example, a voltage may be applied between the inner electrode 6 and the back electrode 7 in a state where the piezoelectric block material 1 is placed in the air or oil.

The thickness of the piezoelectric member 8 is, for example, 50 to 20.
0 μm is preferred. When the thickness exceeds 200 μm, even if a voltage is applied to the inner surface and the back electrodes 6 and 7 to deform the piezoelectric element as described later, the deformation is too small to be sufficient for ejecting droplets. Conversely, if the thickness is less than 50 μm, the thickness is too small and the piezoelectric portion 8 is easily broken during manufacturing and use, and the reliability is low.

By applying a voltage to the inner and back electrodes 6, 7, the piezoelectric element is deformed, so that the first liquid storage chamber formed by the first recess 3 can be expanded and contracted. By expanding the first liquid storage chamber, the liquid stored in the second liquid storage chamber by the second recess 4 can be guided to the first liquid storage chamber through the liquid flow path. In addition, by contracting the first liquid storage chamber, the liquid stored in the first liquid storage chamber can be extruded and ejected to the outside as droplets through the droplet ejection holes 9.

In the liquid droplet ejecting apparatus according to the present invention, as described above, the piezoelectric element is formed using the piezoelectric portion 8 at the bottom of the first liquid storage chamber. That is, since the bottom surface of the first liquid storage chamber is the piezoelectric element as it is, the position of the piezoelectric element is automatically defined by the first concave portion 3. Therefore, if the inner electrode 6 including the bottom surface of the first recess 3 is formed, even if the back electrode 7 is roughly formed at a position corresponding to the first recess 3, the piezoelectric element with respect to the first liquid storage chamber is formed. Can be accurately positioned. Therefore, even if each of the first liquid storage chamber and the piezoelectric element has a fine shape, it is easy to accurately dispose the piezoelectric element at a position corresponding to the first liquid storage chamber. As a result, a droplet ejecting device having a fine structure can be realized, and the resolution of droplet ejection can be increased.

In the droplet ejecting apparatus according to the present invention, the direction of polarization of the piezoelectric element and the direction of the electric field applied to the piezoelectric element coincide. Therefore, it is possible to repolarize the piezoelectric element by applying a voltage to the electrode.

FIG. 3 is a schematic plan view showing another example of the droplet ejecting apparatus according to the present invention. In FIG. 3, for ease of explanation, only the upper surface of the piezoelectric block material 1 is shown, and the lid 2 is omitted. In the apparatus shown in FIG. 3, there are a plurality of first concave portions 3, which are one-dimensionally arranged on the surface of the piezoelectric block 1. Each recess 3 communicates with the second recess 4 via the liquid channel groove 5. The second recess 4 is 1
There may be a single unit or a plurality of units, but it is preferable that the number is one in order to facilitate fabrication of the device. The lid 2 (not shown) is provided with droplet ejection holes 9 one-dimensionally arranged corresponding to the first recess 3.

FIG. 4 is a schematic plan view showing another example of the droplet ejecting apparatus according to the present invention. Also in FIG. 4, only the upper surface of the piezoelectric block 1 is shown, and the lid 2 is omitted.
In the apparatus of FIG. 4, a plurality of first recesses 3 are two-dimensionally arranged on the surface of the piezoelectric block material 1, and each recess 3 communicates with the second recess 4 via the liquid channel groove 5. I have. As described above, it is preferable that the number of the second concave portion 4 is one in order to facilitate manufacture of the device. The lid 2 (not shown) is provided with droplet ejection holes 9 two-dimensionally arranged corresponding to the first recess 3.

The droplet ejecting apparatus as shown in FIGS. 3 and 4 can be applied particularly to an ink jet printer head. This inkjet printer is small,
Since it has a fine and high-precision structure, the interval between nozzles can be reduced, and printing with high drawing resolution can be performed. If the droplet ejecting apparatus as shown in FIG. 4 is used, it is possible to arrange the nozzles of the ink jet printer two-dimensionally. Further, since the adjacent ink pressure chambers can be driven independently of each other, the ink ejection resolution (dpi value) can be further increased. Further, as will be apparent from the manufacturing method described later, the inkjet printer can be manufactured by a simple process group.

Next, the operation of the liquid droplet ejecting apparatus according to the present invention will be described. As an example, a case where the back electrode 7 is thicker than the inner electrode 6 will be described. FIG. 5 is a schematic sectional view showing the operation of the droplet ejecting apparatus shown in FIG. FIG.
5A shows a state where no voltage is applied to the inner surface and the back electrodes 6 and 7, and FIGS. 5B and 5C show a state where voltage is applied to the electrodes.

FIG. 6 is a diagram showing an example of a voltage application schedule to the back electrode 7. First, a positive voltage is applied to the back electrode 10 as shown in FIG. When a positive voltage is applied, the piezoelectric element tends to contract in the in-plane direction due to the piezoelectric transverse effect.
The bending as shown in (b) occurs. This deflection is
This is based on a unimorph operation composed of a back electrode 7 and a piezoelectric element. In such a state, the first liquid storage chamber 3
Expands to a negative pressure inside the chamber, and flows from the second liquid storage chamber 4 through the liquid flow path 5 (in the direction of arrow X in FIG. 5B).
Is filled with excess liquid. Next, FIG.
As shown in (1), a voltage that changes from positive to negative is applied to the back electrode 7 in a short time. When the voltage is applied in this manner, the piezoelectric element tends to expand in the in-plane direction due to the piezoelectric lateral effect, but the relatively thick back electrode 7 causes the deflection as shown in FIG. 5C. . In such a state, the first liquid storage chamber 3 contracts and the pressure in the chamber becomes positive, and the liquid flows from the first liquid storage chamber 4 through the droplet ejection holes 9 (in the direction of arrow Y in FIG. 5C). Injected outside. The time when this voltage changes from positive to negative is defined as a droplet ejection time. Next, the applied voltage is changed from negative to positive at a slow speed.
When the voltage is changed in this manner, the piezoelectric element again attempts to contract in the in-plane direction due to the piezoelectric transverse effect, but the relatively thick back electrode 7 causes the bending as shown in FIG. 5B. In such a state, the first liquid storage chamber 3 expands again to a negative pressure in the chamber, and the first liquid storage chamber 4 passes through the liquid flow path 5 from the second liquid storage chamber 4 (in the direction of arrow X in FIG. 5B). The excess liquid is supplied to the liquid storage chamber 3. This time is defined as the liquid supply time. The total of the liquid ejection time and the liquid supply time is one cycle time. By repeating these operations, droplets can be ejected on demand.

When the inner electrode 6 is thicker than the back electrode 7, the sign of the voltage applied to the back electrode shown in FIG. 6 may be reversed. In this case, the piezoelectric element bends due to the unimorph operation between the inner surface electrode 6 and the piezoelectric element.

Next, a method of manufacturing the liquid droplet ejecting apparatus according to the present invention will be described. This manufacturing method includes (A) a concave portion forming step, (B) an electrode forming step, (C) a lid portion forming step, and (D) a substrate bonding step. Each step will be described below with reference to the schematic cross-sectional views shown in FIGS.

(A) Step of Forming Recess First, as shown in FIG.
Prepare As described above, the piezoelectric block material 1 is made of, for example, a PZT (lead zirconate titanate) -based piezoelectric ceramic material. Next, FIG.
As shown in (b), an etching mask layer 21 of, for example, approximately 0.1 mm thick nickel is formed on one surface (hereinafter, referred to as an upper surface) of the piezoelectric block material 1 by electroless plating or the like in advance. Keep it. Etching mask layer 21
Is formed of a conductive material. For example, copper or the like is used in addition to nickel. Further, the mask layer 21 may be formed by using a known drive process such as electroplating other than electroless plating, vacuum deposition, and sputtering.

As shown in FIG. 7C, patterning is performed on the etching mask layer 21 so as to have the first and second concave portions 3 and 4 and the opening 23 corresponding to the liquid channel groove 5. The formed resist 22 is formed. The patterning is performed, for example, by applying a resist 22 on the entire surface of the mask layer 21 and then exposing and developing through a mask. Alternatively, a resist may be formed by printing only in a portion other than the opening 23.

As shown in FIG. 7D, using the resist 22 as an etching mask, the etching mask layer 21 is etched by argon ion beam etching or the like.
The piezoelectric block material 1 is exposed in the etched portion. As shown in FIG. 7E, reactive ion etching (R) using carbon hexafluoride (SF ₆ ) as a reaction gas is performed.
The piezoelectric block material 1 is etched by the IE) method or the like. The first and second concave portions 3 and 4 are etched.
In addition, a liquid channel groove 5 is formed on the upper surface of the piezoelectric block material 1. FIG. 7E shows a cross-sectional view of the plurality of first recesses 3 formed as an example.

(B) Electrode Forming Step As shown in FIG. 7F, an opening 25 corresponding to the first concave portion 3 and the back wiring electrode (not shown) is formed on the back surface of the piezoelectric block material 1. A resist 24 patterned so as to be provided is provided by a printing method or the like.

Next, as shown in FIG. 8A, a conductive layer 26 such as a 1 μm thick nickel film is formed on the entire upper surface of the piezoelectric block material 1 including the bottom surface and side surfaces of the first concave portion 3. Is formed by vacuum evaporation or the like. Next, a conductive layer 27 such as a nickel film having a thickness of, for example, 10 μm is formed on the entire back surface of the piezoelectric block material 1 by vacuum evaporation or the like.

As shown in FIG. 8B, the resist 2
2 and 24 are removed by dissolving in a solvent or the like. By removing the resist, the conductive layer 2 on the resists 22 and 24 is removed.
6 and 27 are also removed (lifted off) together with the resists 22 and 24. As a result, continuous conductive layers 21 and 26 remain on the entire upper surface of the piezoelectric block material 1. The conductive layer 21
Since the thick etching mask layer 21 is used as it is, it is effective in reducing the resistance. Further, on the back surface of the block material 1, the conductive layer 27 remains at the portion corresponding to the first recess 3 and at the position of the back wiring electrode. As described above, FIG.
(B) inner electrode 6, surface wiring electrode 10, back electrode 7,
And a back wiring electrode (not shown) is formed.

(C) Lid Forming Step First, as shown in FIG. 9A, a lid 2 made of, for example, a quartz glass substrate is prepared. Next, as shown in FIG. 9B, a resist 30 is applied to the surface of the lid 2. As shown in FIG. 9C, the resist 30 is exposed using a photomask (not shown) and then developed to form an opening 31 corresponding to the droplet ejection hole 9 in the resist 30. As shown in FIG. 9D, the lid 2 is etched by reactive ion etching or the like using a well-known mixed gas of CF ₄ and H ₂ to form the droplet ejection holes 9. As shown in FIG. 9E, the resist 30 is removed by dissolving with a solvent or the like, and the lid 2 provided with the droplet ejection holes 9 is manufactured.

(D) Substrate bonding step The piezoelectric block material 1 prepared in the steps (A) and (B)
The lid 2 produced in the step (C) is bonded. First,
As shown in FIG. 10A, an ultraviolet-curing adhesive 32 is precisely applied to the surface of the piezoelectric block material 1 which is in contact with the lid 2. Next, as shown in FIG.
The lid 2 is brought into contact with the upper surface of the piezoelectric block material 1 by positioning the liquid droplet ejecting holes 9 so as to match with each other. After the contact, the adhesive 32 is cured by irradiating ultraviolet rays from above the lid 2. At the time of curing, for example, by sending air from the outside into the first concave portion 3 through the droplet ejection hole 9,
The inside of the concave portion 3 is set to an appropriate positive pressure. This prevents excess adhesive 32 from flowing into the first and second liquid storage chambers and the liquid flow path. (A) ~
By the step (D), the droplet ejecting apparatus shown in FIG. 1 can be manufactured.

Next, another example of the method of manufacturing the liquid droplet ejecting apparatus according to the present invention will be described. This manufacturing method also includes (A) a recess forming step, (B) an electrode forming step, (C) a lid forming step, and (D) a substrate bonding step.

(A) Concavity forming step In the same manner as in FIGS. 7A to 7E, the piezoelectric block material 1 is etched, and the first and second concave parts 3 and 4 are formed.
In addition, a liquid flow channel groove 5 is formed. Next, FIG.
As shown in (a), the resist 22 is removed by dissolving it with a solvent or the like.

(B) Electrode forming step As shown in FIG. 11B, a conductive layer 40 such as a nickel film having a thickness of 0.1 mm is formed on the upper surface of the piezoelectric block material 1 by, for example, sputtering. Thus, FIG.
Are formed as shown in FIG. Next, as shown in FIG. 11C, a resist 24 having an opening 25 corresponding to the first concave portion 3 and the back surface wiring electrode is provided on the back surface of the piezoelectric block material 1 by a printing method or the like. As shown in FIG. 11D, a conductive layer 27 such as a nickel film having a thickness of, for example, 10 μm is formed on the back surface of the piezoelectric block material 1 by vacuum evaporation or the like. FIG.
As shown in (e), the resist 24 is removed by dissolving it with a solvent or the like. By removing, the conductive layer 27 on the resist 24 is removed together with the resist 24 (lift-off).
As a result, the conductive layer 27 remains on the back surface of the piezoelectric block material 1 at the portion facing the first concave portion 3 and at the position of the back wiring electrode. Thus, the back electrode 7 and the back wiring electrode (not shown) of FIG. 1B are formed.

(C) Lid Forming Step The lid 2 is manufactured in the same manner as in FIGS. 9A to 9E. (D) Laminating Step The piezoelectric block 1 and the lid 2 are laminated in the same manner as in FIGS. 10A and 10B. (A) ~
By the step (D), the droplet ejecting apparatus shown in FIG. 1 can be manufactured.

[0050]

As described in detail above, according to the present invention, there is provided a droplet ejecting apparatus which has a high resolution of droplet ejection and can repolarize the piezoelectric element.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view and a cross-sectional view illustrating an example of a droplet ejecting apparatus according to the present invention.

FIG. 2 is a schematic plan view showing an example of a back electrode and a back wiring electrode according to the present invention.

FIG. 3 is a schematic plan view showing another example of the droplet ejecting apparatus according to the present invention.

FIG. 4 is a schematic plan view showing another example of the droplet ejecting apparatus according to the present invention.

FIG. 5 is a schematic cross-sectional view showing the operation of the liquid ejection apparatus according to the present invention.

FIG. 6 is a diagram showing an example of a method of applying a voltage to a piezoelectric element according to the present invention.

FIG. 7 is a process chart showing an example of a method for manufacturing a droplet ejecting apparatus according to the present invention.

FIG. 8 is a process chart showing an example of a method for manufacturing a droplet ejecting apparatus according to the present invention.

FIG. 9 is a process chart showing an example of a method for manufacturing a droplet ejecting apparatus according to the present invention.

FIG. 10 is a process chart showing an example of a method for manufacturing a droplet ejecting apparatus according to the present invention.

FIG. 11 is a process chart showing another example of the method of manufacturing the droplet ejecting apparatus according to the present invention.

FIG. 12 is a sectional view showing a conventional ink jet printer head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Piezoelectric block material 2 ... Lid part 3 ... 1st recessed part 4 ... 2nd recessed part 5 ... Liquid channel groove 6 ... Inner surface electrode 7 ... Back surface electrode 8 ... Piezoelectric part 9 ... Droplet ejection hole 10 ... Front wiring electrode 11 Back wiring electrode 21 Etching mask layer 22, 24, 30 Resist 23, 25, 31 Opening 26, 27, 40 Conductive layer 32 Adhesive

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Seiya Takahashi 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Industrial Co., Ltd. (72) Katsuhiro Wakabayashi 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (72) Inventor Yukihiko Sawada 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (72) Inventor Masaki Esashi 1-chome, Yagiyama-minami, Taihaku-ku, Sendai-city, Miyagi Prefecture. No. 11-9 (72) Inventor: Shio Wang 3-12-8 F-term, 3-12-8 Yawata, Aoba-ku, Sendai, Miyagi Prefecture (Reference) 2C057 AF93 AG92 AG93 AP02 AP32 AP52 AP53 AP54 AP55 BA04 BA14 4F033 AA14 BA03 CA07 DA05 EA01 JA03 JA06 NA01

Claims (5)

[Claims] 1. A piezoelectric element substrate having, on a surface thereof, first and second recesses for accommodating a liquid and a liquid flow path connecting these recesses, and an inner surface of the first recess. An inner electrode formed on the piezoelectric element substrate, a back electrode formed on the back surface of the piezoelectric element substrate facing the bottom surface of the first recess, and a droplet ejection hole at a position corresponding to the first recess. And a lid mounted on the surface of the piezoelectric element substrate so as to cover the first and second recesses and the liquid flow path. 2. The droplet ejecting apparatus according to claim 1, wherein a plurality of the first concave portions are provided, and are arranged one-dimensionally on a surface of the piezoelectric element substrate. 3. The droplet ejecting apparatus according to claim 1, wherein there are a plurality of the first concave portions, and the first concave portions are two-dimensionally arranged on the surface of the piezoelectric element substrate. 4. An inner surface electrode formed along an inner surface of the plurality of first recesses is connected by a conductor layer formed on an upper surface of a piezoelectric element substrate, and the back electrode is formed of a plurality of first recesses. The droplet ejecting device according to claim 2, wherein the droplet ejecting device is provided independently at a position corresponding to the bottom surface. 5. The droplet ejecting apparatus according to claim 1, wherein the first and second concave portions are formed by dry-etching a piezoelectric element substrate.