CN100505357C - Piezoelectric element, liquid-jet head and liquid-jet equipment - Google Patents
Piezoelectric element, liquid-jet head and liquid-jet equipment Download PDFInfo
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- CN100505357C CN100505357C CNB2006100651402A CN200610065140A CN100505357C CN 100505357 C CN100505357 C CN 100505357C CN B2006100651402 A CNB2006100651402 A CN B2006100651402A CN 200610065140 A CN200610065140 A CN 200610065140A CN 100505357 C CN100505357 C CN 100505357C
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Abstract
Disclosed are a piezoelectric element, which has a high withstand voltage and a longer durability life, a liquid-jet head and a liquid-jet apparatus. The piezoelectric element includes a lower electroDisclosed are a piezoelectric element, which has a high withstand voltage and a longer durability life, a liquid-jet head and a liquid-jet apparatus. The piezoelectric element includes a lower electrode provided above a substrate, a piezoelectric layer provided above the lower electrode, and an upper electrode provided above the piezoelectric layer, and an electric resistivity of the piezoelectricde provided above a substrate, a piezoelectric layer provided above the lower electrode, and an upper electrode provided above the piezoelectric layer, and an electric resistivity of the piezoelectric layer is not lower than 20M Ohm.c.m. layer is not lower than 20M Ohm.c.m.
Description
Technical field
The present invention relates to include the piezoelectric element of bottom electrode, piezoelectric layer and top electrode.Particularly, the present invention relates to from the jet head liquid of jet hole liquid droplets and the piezoelectric element that is used for liquid injection device.
Background technology
Ink jet print head with following structure has dropped into actual use.According to this structure, the part of the pressure generation chamber that is connected with jet hole that from then on ink droplet sprays is made of oscillating plate.Oscillating plate is out of shape by piezoelectric element, so the ink pressurized in each pressure generation chamber.Thus, from each jet hole, spray ink droplet.For example the ink jet print head of structure belongs to such ink jet print head as follows.On the whole surface of oscillating plate, form the conforming layer of making by piezoelectric by using film to form technology.Then, will be somebody's turn to do the layer of being made by piezoelectric by photoetching process cuts into and the corresponding shape of pressure generation chamber.Piezoelectric element thus, in pressure generation chamber, forms piezoelectric element respectively, so that can be mutually independent.
Comprise having being suggested, and leakage current is to suppress by the component that a certain amount of halogen material that will be contained in wherein is set at piezoelectric layer as the piezoelectric element that is used for this ink jet print head by the piezoelectric element that suppresses the withstand voltage that its leakage current improves.(opening the claims in the 11st page of No.2004-107181 referring to for example Japan Patent spy)
But the spy opens No.2004-107181 according to Japan Patent, though the leakage current of piezoelectric layer can be suppressed, the resistivity of piezoelectric layer is not set.Therefore, there are the following problems, if promptly resistivity is lower, increases the durability deterioration that causes piezoelectric layer owing to leakage current.
Should be noted that such problem is not limited to the jet head liquid of ink jet print head representative.In other piezoelectric element, also there is similar problem.
Summary of the invention
Consider above-mentioned situation, the purpose of this invention is to provide a kind of piezoelectric element, a kind of jet head liquid and a kind of liquid injection device with high withstand voltage and longer viability.
The a first aspect of the present invention that is used to solve foregoing problems is a kind of piezoelectric element, it is characterized in that comprising: be arranged on the bottom electrode on the substrate; Be arranged on the piezoelectric layer on the described bottom electrode; With the top electrode that is arranged on the described piezoelectric layer, wherein, the resistivity of described piezoelectric layer is not less than 20M Ω cm.
In first aspect, by setting the resistivity of piezoelectric element, can improve the withstand voltage of piezoelectric element, can improve its endurance life simultaneously, can improve its reliability thus.
A second aspect of the present invention is the piezoelectric element as a first aspect of the present invention, it is characterized in that the withstand voltage of described piezoelectric layer is not less than 900kV/cm.
In second aspect,, the endurance life that can improve piezoelectric layer, can improve its reliability thus by setting the withstand voltage of piezoelectric element.
A third aspect of the present invention is as each piezoelectric element in a first aspect of the present invention and the second aspect, it is characterized in that the leakage current of described piezoelectric layer is not more than 1 * 10
-8A/cm
2
In the third aspect,, the endurance life that can improve piezoelectric layer, can improve its reliability thus by setting the leakage current of piezoelectric element.
A fourth aspect of the present invention is that the relative dielectric constant that it is characterized in that described piezoelectric layer is 750 to 1500 as a first aspect of the present invention each piezoelectric element to the third aspect.
In fourth aspect, the degree of crystallinity of piezoelectric layer is significantly increased.Therefore, can provide placement property excellent and have the piezoelectric element of high withstand voltage and longer endurance life.
A fifth aspect of the present invention is that the coercive electric field that it is characterized in that described piezoelectric layer is 15 to 30kV/cm, and remanent polarization is 10 to 25 μ C/cm as a first aspect of the present invention each piezoelectric element to the fourth aspect
2
In aspect the 5th, the degree of crystallinity of piezoelectric layer is further improved.Therefore, are further improved the placement property of piezoelectric element and endurance life.
A sixth aspect of the present invention is a kind of piezoelectric element, it is characterized in that comprising: be arranged on the bottom electrode on the substrate; Be arranged on the piezoelectric layer on the described bottom electrode; With the top electrode that is arranged on the described piezoelectric layer, described piezoelectric element is characterised in that the resistivity of described piezoelectric layer is not less than 20M Ω cm, and the leakage current of described piezoelectric layer is not more than 1 * 10
-8A/cm
2, and the withstand voltage of described piezoelectric layer is not less than 900kV/cm.
In aspect the 6th,, can improve its reliability thus by setting the endurance life that its resistivity, leakage current and withstand voltage can improve piezoelectric element.
A seventh aspect of the present invention is a kind of jet head liquid, it is characterized in that comprising: as each piezoelectric element in first aspect to the six aspects; Form substrate with passage, described piezoelectric element is placed in described passage at oscillating plate and forms and be set to described passage under the situation between substrate and the described piezoelectric element and form substrate, and the pressure generation chamber that is communicated with jet hole is set to described passage formation substrate.
In the situation aspect the 7th, can obtain such jet head liquid, be enhanced thereby be enhanced its reliability its endurance life.
A eighth aspect of the present invention is a kind of liquid injection device, it is characterized in that comprising the jet head liquid as the 7th aspect.
In the situation of eight aspect, can obtain such liquid injection device, be enhanced thereby be enhanced its reliability its endurance life.
Description of drawings
Fig. 1 shows the decomposition diagram according to the schematic configuration of the recording head of first embodiment.
Fig. 2 A and 2B are respectively according to the vertical view of the recording head of embodiment 1 and cutaway view.
Fig. 3 shows the figure line of example of the hysteresis loop (hysteresis loop) of piezoelectric layer.
Fig. 4 A to Fig. 4 C is the cutaway view that illustrates according to the manufacture method of the recording head of first embodiment.
Fig. 5 A is the cutaway view that illustrates according to the manufacture method of the recording head of first embodiment to Fig. 5 C.
Fig. 6 A is the cutaway view that illustrates according to the manufacture method of the recording head of first embodiment to Fig. 6 D.
Fig. 7 illustrates the displacement of sample piezoelectric element and the figure line of displacement reduction rate.
Fig. 8 shows the view according to the schematic configuration of the tape deck of an embodiment.
Embodiment
To describe the present invention in detail based on embodiment below.
(first embodiment)
Fig. 1 is the decomposition diagram according to the ink jet print head of the first embodiment of the present invention.Fig. 2 A is the vertical view of the ink jet print head shown in Fig. 1, and Fig. 2 B is the cutaway view of the ink jet print head got of the line A-A ' along Fig. 2 A.
In the situation of present embodiment, passage forms substrate 10 and is made by monocrystalline substrate, as shown in the figure.Form at passage on one of two surfaces of substrate 10 and form elastic membrane 50.Elastic membrane 50 has the thickness of 0.5 to 2 μ m, and is made by the silicon dioxide that forms by thermal oxidation in advance.
Form in the substrate 10 at passage,, arrange a plurality of pressure generation chambers 12 that separate by partition wall 11 abreast by forming substrate 10 from opposite side anisotropic etching passage.Connected component 13 is formed on vertical outside of pressure generation chamber 12.Connected component 13 constitutes the part of fluid reservoir 100, and described fluid reservoir 100 is the common ink water cavities that are used for pressure generation chamber 12.Connected component 13 and each pressure generation chamber 12 end on vertically is communicated with by its ink feed path 14.Each ink feed path 14 forms with the narrower width of width that specific pressure produces chamber 12, and makes ink keep constant from the channel resistance that connected component 13 flow into the pressure generation chamber 12.
On the other hand, as mentioned above, form at passage on another surface of an opposite side with open surfaces of substrate 10, form elastic membrane 50.The thickness of elastic membrane 50 is for example made for about 1.0 μ m and by silicon dioxide.Dielectric film 55 is formed on this elastic membrane 50 by it being layered on this elastic membrane 50.Dielectric film 55 is by zirconia (ZrO
2) wait and make, and its thickness is about 0.4 μ m.In addition, use the technology that will be described later,, on this dielectric film 55, form lower electrode film 60, piezoelectric layer 70 and upper electrode film 80 by it is laminated to each other.Each piezoelectric element 300 is made of lower electrode film 60, a piezoelectric layer 70 and a upper electrode film 80.The thickness of lower electrode film 60 for example is about 0.1～0.5 μ m.Each piezoelectric layer 70 is made by lead zirconate titanate (PZT) etc., and has and for example be the thickness of about 1.0 μ m.Each top electrode 80 is made by gold, platinum, iridium etc., and has and for example be the thickness of about 0.05 μ m.
At this, piezoelectric element 300 is the parts that comprise lower electrode film 60, a piezoelectric layer 70 and a upper electrode film 80.Generally speaking, piezoelectric element 300 is configured as follows.One in two electrodes of piezoelectric element 300 is used as public electrode.Another electrode and piezoelectric layer 70 are patterned according to each pressure generation chamber 12.In the part that constitutes that is patterned accordingly in patterned piezoelectric layer 70 and two electrodes, owing to piezoelectric strain is taken place two electrode application voltage.This part is called as " piezoelectricity active part ".In the present embodiment, lower electrode film 60 is used as the public electrode of piezoelectric element 300, and upper electrode film 80 is as the single electrode of piezoelectric element 300.But, for the convenience of drive circuit and interconnection line its purposes is put upside down, do not have any problem yet.In both cases, in each pressure generation chamber, all form the piezoelectricity active part respectively.Herein, the combination of piezoelectric element 300 and oscillating plate is called as " piezo-activator ".Oscillating plate relies on the driving of piezoelectric element 300 and displacement is provided.Along band ground, in foregoing example, elastic membrane 50, dielectric film 55 and lower electrode film 60 are jointly served as oscillating plate.But, need not many speeches, this is not restrictive.For example, can only make lower electrode film 60 serve as oscillating plate, and elastic membrane 50 and dielectric film 55 need not be provided.
Notice that the piezoelectric layer 70 of present embodiment has the resistivity of 20M Ω cm at least.By such resistivity is set, can prevents that leakage current from becoming big, and can prolong the endurance life of piezoelectric layer 70.The leakage current of this piezoelectric layer 70 preferably is not more than 1 * 10
-8A/cm
2In addition, the withstand voltage of piezoelectric layer 70 preferably is not less than 900kV/cm.Set the leakage current and the withstand voltage of piezoelectric layer 70 as described above, can prolong the endurance life of piezoelectric layer 70.
In addition, such piezoelectric layer 70 has 750～1500 relative dielectric constant.In addition, the characteristic of such piezoelectric layer 70 is that coercive electric field is Ec=15～30kV/cm (2Ec=30～60kV/cm), and remanent polarization is Pr=10～25 μ C/cm
2(2Pr=20～50 μ C/cm
2).Notice that coercivity electric field ec and remanent polarization Pr for example are the 2Er of the hysteresis loop (hysteresis loop) that utilizes piezoelectric layer as shown in Figure 3 and the value that 2Pr obtains.
For the piezoelectric layer 70 with such characteristic, it is especially excellent that its piezoelectric constant becomes, in other words, and piezoelectric constant d
31Become 150～250pC/N.Therefore, improved the placement property of piezoelectric element 300.In addition, as this piezoelectric layer 70 of present embodiment, as example is by showing the electromechanical transition effects and having the crystal film that the ferroelectric ceramic material of perovskite structure is made.As the material that is used for piezoelectric layer 70, for example, ferroelectric-piezoelectric and be desirable by metal oxide being added to this ferroelectric-resulting material of piezoelectric etc.Ferroelectric-piezoelectric like this comprises lead zirconate titanate (PZT).Such metal oxide comprises niobium oxide, nickel oxide and magnesium oxide.Particularly, can use lead titanates (PbTiO
3), lead zirconate titanate (Pb (Zr, Ti) O
3), lead zirconates (PbZrO
3), load lanthanium titanate ((Pb, La) TiO
3), lead lanthanum zirconate titanate ((Pb, La) (Zr, Ti) O
3), magnesium zirconate-titanate lead niobate (Pb (Zr, Ti) (Mg, Nb) O
3) etc.In this embodiment, the material that comprises Pb (lead), Zr (zirconium) and Ti (titanium) is used to piezoelectric layer 70 in the mode that satisfies formula Pb/ (Zr+Ti)=1.0～1.3.Therefore, excessive lead is accumulated in the crystal boundary in case stopping leak electric leakage rheology is big, can set leakage current thus.
In addition, at least a dopant that preferably will be selected from nickel (Ni), manganese (Mn) and strontium (Sr) is doped to the piezoelectric layer 70 of present embodiment.As mentioned above, by predetermined dopant is doped to piezoelectric layer 70, can set the resistivity, leakage current, withstand voltage, relative dielectric constant, remanent polarization, coercive electric field, piezoelectric constant of piezoelectric layer 70 etc.The amount that the amount of such dopant is preferably predetermined, specifically, be no more than its 10%." be no more than 10% " and the amount with dopant that do not mean that reduces better in this setting.The upper limit of setting " being no more than 10% " is because a large amount of dopants causes reducing of piezoelectric layer 70 displacements.Need not many speeches, piezoelectric layer 70 can not comprise any nickel (Ni), manganese (Mn) and strontium (Sr).Even in such circumstances, also can obtain to have the piezoelectric layer 70 of desired characteristic.
In addition, piezoelectric layer 70 is formed with certain thickness, and this thickness prevents to crack in piezoelectric layer 70 in manufacture process, and makes piezoelectric layer 70 can fully show its placement property.In this embodiment, for example, piezoelectric layer 70 is formed the thickness of about 1 μ m to 2 μ m.
In addition, extraction electrode 90 is connected to each upper electrode film 80, and described upper electrode film 80 is the single electrodes that are used for each piezoelectric element 300.Extraction electrode 90 is drawn near the end of corresponding ink feed path 14, and extends to the top of dielectric film 55.Extraction electrode 90 is made by for example gold (Au) etc.
In addition, piezoelectric element holding portion 32 zone relative that be set at baffle 30 with piezoelectric element 300.Piezoelectric element holding portion 32 has a cavity, and this cavity is enough big, and piezoelectric element 300 is moved in the clear.If baffle 30 has the big cavity that must be enough to make piezoelectric element 300 to move in the clear, and is just enough.Whether cavity is hermetically enclosed is unessential.
It is desirable to, have with material that passage forms the identical thermal coefficient of expansion of substrate 10 and be used to such baffle 30.The example of described material comprises glass, ceramic material etc.In the present embodiment, baffle 30 by as with form the monocrystalline substrate that passage forms substrate 10 identical materials and form.
In addition, baffle 30 is provided with along the through hole 33 of thickness direction pierce through the protection plate 30.And near the part of the end of the extraction electrode 90 of drawing from piezoelectric element 300 is arranged in the mode that near part this is exposed to through hole 33 respectively.And drive circuit 110 is fixed to the top of baffle 30.Drive circuit 110 drives the piezoelectric element of arranging along parallel lines 300.For example, circuit board, semiconductor integrated circuit (IC) etc. can be used as this drive circuit 110.In addition, drive circuit 110 is electrically connected by being connected interconnection 120 mutually with each extraction electrode 90.Connecting interconnection 120 is made by the lead such as wire bonds.
In addition, flexible board (compliance plate) 40 is engaged to baffle 30 tops.Flexible board 40 is made of diaphragm seal 41 and fixed head 42.At this, diaphragm seal 41 is made by the flexible material (for example, thickness is polyphenylene sulfide (PPS) film of 6 μ m) of relatively low stiffness.One end of fluid reservoir part 31 is hermetically enclosed by sealing film 41.In addition, fixed head 42 is by forming such as the hard material of metal (for example, thickness is the stainless steel (SUS) of 30 μ m etc. etc.).The zone relative with fluid reservoir 100 of this fixed head 42 is opening portions 43, and this opening portion 43 obtains by the part corresponding to this zone of removing fixed head along thickness direction fully.Therefore, an end of fluid reservoir 100 is only sealed by the diaphragm seal 41 of flexibility.
Be used for ink feed is formed on to the ink inlet port 44 of fluid reservoir 100 part of flexible board 40.This part of flexible board 40 is in the outside of fluid reservoir 100, and is positioned at roughly on the position corresponding to the center longitudinally of fluid reservoir 100.In addition, baffle 30 is provided with ink and introduces path 35, introduces path 35 by ink, and the sidewall of ink inlet port 44 and fluid reservoir 100 is interconnected.
Such ink jet print head according to present embodiment sucks ink from the ink inlet port 44 that is connected with external ink feeding mechanism (not shown), and will be full of ink in the inside in 21 scopes from fluid reservoir 100 to jet hole.Then, according to tracer signal, between corresponding to each upper electrode film 80 of pressure generation chamber 12 and lower electrode film 60, apply voltage from drive circuit.Thus, ink jet print head makes elastic membrane 50, lower electrode film 60 and piezoelectric layer 70 be out of shape with case of bending.This distortion is risen the pressure in each pressure generation chamber 12, thus from jet hole 21 ejection ink droplets.
After this, will provide description to Fig. 6 D with reference to figure 4A for the method for making such ink jet print head.Notice that Fig. 4 A is pressure generation chamber 12 cutaway view longitudinally to Fig. 6 D.At first, shown in Fig. 4 A, the passage of making by monocrystalline substrate form substrate 10 in diffusion furnace under about 1100 ℃ by thermal oxidation.Thus, form silicon dioxide film 52 on the surface of passage formation substrate 10, this silicon dioxide film 52 will become elastic membrane 50 and diaphragm 51 in the back.Subsequently, shown in Fig. 4 B, zirconium (Zr) layer is formed on the elastic membrane 50 (silicon dioxide film 52).After this, by for example in diffusion furnace at 500 ℃～1200 ℃ following hot zirconias (Zr) layers, form by zirconia (ZrO
2) insulating barrier 55 made.
Then, shown in Fig. 4 C, whole formation iridium, platinum etc. on the top of passage formation substrate 10.After this, form bottom electrode 60 by the mode that is patterned into reservation shape.
Subsequently, piezoelectric layer 70 is formed on the bottom electrode 60.At this, utilize the method that is called as sol-gal process to form piezoelectric layer 70 in the present embodiment.According to sol-gal process, what be called as colloidal sol is by with metallorganic matter dissolving with to be dispersed in catalyst resulting.Coating and dry described colloidal sol are to form gel.Under higher temperature, cure described gel then.Obtain the piezoelectric layer 70 made by metal oxide thus.In addition, the method for manufacturing piezoelectric layer 70 is not limited to sol-gal process.For example, also can use MOD (deposition of metal organic) method etc.
The material that is used for piezoelectric layer 70 is the material of a kind of Pb of containing, Zr and Ti.In this embodiment, piezoelectric layer 70 is formed by lead zirconate titanate (PZT).In addition, the piezoelectric layer 70 of present embodiment forms based on formula Pb/ (Zr+Ti)=1.0～1.3.In other words, piezoelectric layer 70 comprises and is no more than 30% excessive lead.Be no more than 30% excessive lead by making piezoelectric layer 70 comprise, prevented that the leakage current of piezoelectric layer 70 from becoming big.In addition, at least a dopant that preferably will be selected from Ni, Mn and Sr is doped to piezoelectric layer 70.Excessive dopant reduces the displacement of piezoelectric layer 70.Therefore, preferably, the amount of dopant is no more than 10% of piezoelectric layer 70.
The detailed process that forms piezoelectric layer 70 is as follows.Shown in Fig. 5 A, at first, be formed on the lower electrode film 60 as the piezoelectricity precursor film 71 of PZT presoma.In other words, comprise metal-organic colloidal sol (liquid solution) and be applied to the top (in application step) that is formed on the lower electrode film 60 on the passage formation substrate 10.
Subsequently, heating piezoelectricity precursor film 71 under predetermined temperature, and so dry regular hour.In the present embodiment, can be for example by piezoelectricity precursor film 71 be kept coming in 8～30 minutes dry piezoelectricity precursor film 71 down at 170～180 ℃.In addition, it is desirable to, the speed that temperature raises in drying steps is 0.5～1.5 ℃/second.Along band ground, mentioned here " speed that temperature raises " is defined as from temperature 1 to temperature 2 the temperature change speed with respect to the time.In order to following method accounting temperature 1 and temperature 2.Poor between the temperature that beginning, temperature (room temperature) when obtaining the heating beginning and piezoelectricity precursor film 71 reach by heating.Then, obtain temperature 1 by 20% temperature that is added to when beginning heating that will differ from.Obtain temperature 2 by 80% temperature that is added to when beginning heating that will differ from.For example wherein temperature in 50 seconds, be raised under 100 ℃ the situation from 25 ℃ of room temperatures, the speed that temperature raises is as follows:
(100-25) * (0.8-0.2)/50=0.9[℃/second]
Subsequently, be heated to predetermined temperature and this film is kept the regular hour under this temperature, piezoelectricity precursor film 71 is carried out degreasing by the piezoelectricity precursor film 71 that will be dried.In the situation of present embodiment, for example, this film is carried out degreasing under this temperature by piezoelectricity precursor film 71 being heated to about 300～400 ℃ temperature and this film being kept about 10～30 minutes.Along band ground, the meaning of degreasing is included in organic component in the piezoelectricity precursor film 71 for example with NO referred in this
2, CO
2, H
2O etc. are removed from it.In defatting step, it is desirable to, the speed that temperature raises is 0.5～1.5 ℃/second.
Then, shown in Fig. 5 B, piezoelectricity precursor film 71 is heated to predetermined temperature, and keeps the regular hour under this temperature, carries out crystallization thus.So piezoelectric film 72 is formed (in baking step).In baking step, it is desirable to, piezoelectricity precursor film 71 is heated to 650～750 ℃ temperature.In the present embodiment, piezoelectricity precursor film 71 was heated 30 minutes at 680 ℃.And, in baking step, it is desirable to, the speed that temperature raises is no more than 15 ℃/second.As described, in by the situation of curing formation piezoelectric film 72, preferably, piezoelectricity precursor film 71 is heated at least 30 minutes.So, the piezoelectric film 72 that can obtain having excellent specific property.
Notice that for example RTP (rapid thermal treatment) system can be used as the heating system that is used for drying, degreasing and baking step.The RTP system carries out heat treatment by the radiation from hot plate or infrared lamp.
Then, the piezoelectric layer that comprises aforesaid coating, drying, degreasing and baking step forms step and is repeated repeatedly.In the situation of present embodiment, piezoelectric layer forms step and is repeated ten times.Like this, shown in Fig. 5 C, form the piezoelectric layer with predetermined thickness 70 that comprises ten lamination electrolemmas 72.The thickness that is coated with each time of colloidal sol is in the situation of about 0.1 μ m therein, and total thickness of piezoelectric film 70 is about 1.1 μ m.
Note, in the technology of reality, form first and second piezoelectric films 72 by curing a plurality of piezoelectricity precursor film 71 respectively.The 3rd and film subsequently form as follows.At first, carry out coating, drying and defatting step twice in the piezoelectricity precursor film 71 each.Subsequently, in baking step, once cure two piezoelectricity precursor film 71.In other words, cure, can form the piezoelectric layer of forming by ten lamination electrolemmas 72 70 by carrying out six times.At this, preferably, be no more than three hours for total time of curing of such piezoelectric layer 70.This makes that forming the piezoelectric layer 70 with excellent specific property becomes possibility.
By forming piezoelectric layer 70 by this way, the resistivity of piezoelectric layer 70 can be greater than 20M Ω cm.In other words, by setting resistivity by this way, can prevent that leakage current from becoming big, and can prolong the endurance life of piezoelectric layer 70.In addition, the manufacture method of the piezoelectric layer 70 of present embodiment can form leakage current and be not more than 1 * 10
-8A/cm
2And withstand voltage is not less than the piezoelectric layer 70 of 900kV/cm.By leakage current and the withstand voltage of setting piezoelectric layer 70 in this way, can prolong the endurance life of piezoelectric layer 70.
Therefore, under the condition of present embodiment, form in the situation of piezoelectric layer 70, can form reliably and have the piezoelectric layer 70 that relative dielectric constant is 750～1500 excellent specific property.At this, in the situation that piezoelectric layer 70 is formed under such condition, the coercivity electric field ec of piezoelectric layer 70 is that the remanent polarization Pr of about 15～30kV/cm and piezoelectric layer 70 is about 10～25 μ C/cm
2
In addition, passing through Fig. 5 A after the step shown in Fig. 5 C forms piezoelectric layer 70, upper electrode film 80 is formed on the whole surface of passage formation substrate 10, as shown in Figure 6A.Upper electrode film 80 is made by for example iridium.Then, piezoelectric layer 70 and upper electrode film 80 are patterned as respectively each of a plurality of zones relative with a plurality of pressure generation chamber 12.So, form piezoelectric element 300.
Formed by this way piezoelectric layer 70 has the piezoelectric constant d up to 150～250 (pC/N)
31, the placement property of piezoelectric element 300 is significantly increased thus.So, can improve characteristics of inkjet.
Subsequently, form extraction electrode 90.Particularly, extraction electrode 90 is formed as follows.Shown in Fig. 6 B, at first, extraction electrode 90 is formed on the whole surface of passage formation substrate 10.Extraction electrode 90 is made by for example gold (Au) etc.After this, by use by photoresist etc. make mask pattern (not shown) patterning extraction electrode 90 in each piezoelectric element 300.
Then, shown in Fig. 6 C, for example utilize adhesive 34, join baffle 30 to top that passage forms substrate 10.Baffle 30 holds a plurality of piezoelectric elements 300 that are patterned like this.Along band ground, fluid reservoir part 31 and piezoelectric element holding portion 32 etc. is formed in the baffle 30 in advance.In addition, baffle 30 is that the monocrystalline substrate of about 400 μ m is made by for example thickness.Join baffle 30 to passage and form the rigidity that substrate 10 has increased gained passage formation substrate 10 significantly.
Subsequently, shown in Fig. 6 D, the silicon dioxide film 52 on the surface by passage being formed substrate 10 (this surface and form the surface opposite of piezoelectric element 300 on it) is patterned to reservation shape, forms diaphragm 51.Under with the situation of diaphragm 51, use alkaline solution that passage formation substrate 10 is carried out anisotropic etching (wet etching) such as KOH as mask.Thus, form formation pressure generation chamber 12, connected component 13, ink feed path 14 etc. in the substrate 10 at passage.
Subsequently, nozzle plate 20 is engaged to the surface that passage forms substrate 10, and described surface and baffle 30 have been engaged to the surface opposite on it.In nozzle plate 20, be drilled with jet hole 21.Simultaneously, flexible board 40 is engaged on the baffle 30.Thus, formed ink jet print head as shown in Figure 1.
Note, by the film formation and the anisotropic etching of aforesaid multi-series, a large amount of chip of once actual formation on single wafer.After this technology was finished, wafer was divided into the passage that as shown in Figure 1 each has die size and forms substrate 10.So, formed ink jet print head.
According to the present invention, as mentioned above, each in the piezoelectric layer 70 of formation piezoelectric element 300 is formed has the resistivity that is not less than 20M Ω cm.This has increased the piezoelectric constant d of piezoelectric layer 70
31Therefore, improved the placement property of piezoelectric element 300.In addition, improved the degree of crystallinity of piezoelectric layer 70.Therefore, for example, the withstand voltage of piezoelectric layer 70 can be not less than 900kV/cm, and its leakage current can be not more than 1 * 10 simultaneously
-8A/cm
2Thus, can be significantly longer the endurance life of piezoelectric layer 70.
At this, the sample of piezoelectric element with above-mentioned characteristic has been carried out durability test, wherein, predetermined driving pulse is applied to this sample 30,000,000,000 times continuously.Fig. 7 shows the displacement of piezoelectric element and the testing result that displacement reduces.Along band ground, for the sample piezoelectric element, the thickness of piezoelectric layer is 1.5 μ m, and the thickness of lower electrode film is 200nm, and the thickness of upper electrode film 80 is 50nm.The driving pulse that applies in durability test is that the frequency of 50V voltage is the sine wave of 100kHz.The driving pulse that applies in the displacement measurement process is that the frequency of 30V voltage is the trapezoidal wave of 800Hz.
As shown in Figure 7, for piezoelectric element according to the present invention, its displacement reduces along with the increase of the number of times of the pulse of bearing, and in other words, the displacement reduction rate increases.But even after applying 30,000,000,000 times driving pulse, the displacement reduction rate is quite low by 13.3%.Find out obviously that from the result according to the present invention, the viability of piezoelectric element (piezoelectric layer) significantly improves.
(other embodiment)
The first embodiment of the present invention described above.But the essential structure of ink jet print head is not limited to aforesaid structure.In the first above-mentioned embodiment, for example, formed piezoelectric layer by using sol-gal process or MOD method.But it is not restricted to this particularly.For example, piezoelectric layer can form by sputtering method.Forming by described sputtering method in the situation of piezoelectric film, it is just enough under 650～750 ℃ the piezoelectricity precursor film to be carried out the after annealing of half an hour to three hour.
In addition, in the first above-mentioned embodiment, at least a dopant that is selected from nickel (Ni), manganese (Mn) and strontium (Sr) is doped in each piezoelectric layer 70 that constitutes piezoelectric element 300.But it is not restricted to this particularly.Even without nickel (Ni), manganese (Mn) and strontium (Sr) etc. are doped to wherein, also can obtain to have the piezoelectric layer 70 of desired characteristic.
In addition, constituted the part of head unit according to each the ink jet print head of these embodiment, and be installed in the ink-jet recording apparatus with the ink channel that is communicated with print cartridge etc.Fig. 8 shows the schematic configuration figure of the example of ink-jet recording apparatus.
As shown in Figure 8, comprise that the head unit 1A of ink jet print head separately and 1B removably are set to box 2A and the 2B that constitutes ink supply unit.The carriage 3 that head unit 1A and 1B are installed on it is set to the bracket axle 5 that is fixed in apparatus main body 4 in such a way: promptly carriage 3 can freely move on the direction that described axle extends.Designated black ink composition and the color inks composition of spraying respectively of these head unit 1A and 1B.
In addition, from the actuating force of drive motors 6 by a plurality of gears that do not illustrate be with 7 to be delivered to carriage 3 synchronously.Thus, make the carriage 3 that head unit 1A and 1B are installed on it move along bracket axle 5.On the other hand, apparatus main body 4 is provided with the cylinder 8 along bracket axle 5.Be designed to transmission on cylinder 8 as the recording medium such as the scraps of paper and by the documentary film S that feeding-in roll etc. is sent into, wherein feeding-in roll is not shown.
Note,, the invention is intended to broadly be applied to the gamut of jet head liquid though toply under with the situation of ink jet print head, described first embodiment as the example of jet head liquid.The self-explantory the present invention of being can be applied to spray any jet head liquid of the liquid that is different from ink.The example of jet head liquid that injection is different from the liquid of ink comprises: be used for the various recording heads such as the image recording of printer; Be used to make the pigment injector head of the colour filtering of liquid crystal indicator etc.; Be used to form the electrode material injector head of electrode of organic EL display and FED (Field Emission Display) device etc.; The biological organic substance that is used to make biochip sprays first-class.
Claims (5)
1. piezoelectric element comprises:
Be arranged on the bottom electrode on the substrate;
Be arranged on the piezoelectric layer on the described bottom electrode; With
Be arranged on the top electrode on the described piezoelectric layer,
Wherein, at least a dopant that is selected from nickel, manganese, the strontium is doped in the described piezoelectric layer,
The resistivity of described piezoelectric layer is not less than 20M Ω cm,
The leakage current of described piezoelectric layer is not more than 1 * 10
-8A/cm
2, the coercive electric field of described piezoelectric layer is 15 to 30kV/cm,
The relative dielectric constant of described piezoelectric layer is 750 to 1500.
2. piezoelectric element as claimed in claim 1, wherein, the withstand voltage of described piezoelectric layer is not less than 900kV/cm.
3. piezoelectric element as claimed in claim 1, wherein, the remanent polarization of described piezoelectric layer is 10 to 25 μ C/cm
2
4. jet head liquid comprises:
As each described piezoelectric element in the claim 1 to 3; With
Passage forms substrate, described piezoelectric element is placed in described passage at oscillating plate and forms and be set to described passage under the situation between substrate and the described piezoelectric element and form substrate, and the pressure generation chamber that is communicated with jet hole is set to described passage formation substrate.
5. a liquid injection device comprises jet head liquid as claimed in claim 4.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
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| JP2005081729 | 2005-03-22 | ||
| JP2005081729 | 2005-03-22 | ||
| JP2005356706 | 2005-12-09 |
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| CN100505357C true CN100505357C (en) | 2009-06-24 |
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| CNB2006100651402A Expired - Fee Related CN100505357C (en) | 2005-03-22 | 2006-03-21 | Piezoelectric element, liquid-jet head and liquid-jet equipment |
| CNB2006100651417A Expired - Fee Related CN100479218C (en) | 2005-03-22 | 2006-03-21 | Piezoelectric element, liquid-jet head, method of manufacturing the same, and liquid-jet apparatus |
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| CNB2006100651417A Expired - Fee Related CN100479218C (en) | 2005-03-22 | 2006-03-21 | Piezoelectric element, liquid-jet head, method of manufacturing the same, and liquid-jet apparatus |
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| JP (1) | JP2009049433A (en) |
| CN (2) | CN100505357C (en) |
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| JP4821566B2 (en) * | 2006-11-08 | 2011-11-24 | セイコーエプソン株式会社 | Liquid discharge head |
| JP2011091234A (en) * | 2009-10-23 | 2011-05-06 | Seiko Epson Corp | Liquid ejection head, liquid ejection device and actuator device |
| JP2017136724A (en) * | 2016-02-02 | 2017-08-10 | 東芝テック株式会社 | Ink jet head |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3576788B2 (en) * | 1998-02-13 | 2004-10-13 | 株式会社東芝 | Electronic component and method of manufacturing the same |
| EP0991130B1 (en) * | 1998-03-04 | 2007-12-12 | Seiko Epson Corporation | Piezoelectric device, ink-jet recording head, method for manufacture, and printer |
| JP2001152360A (en) * | 1999-11-25 | 2001-06-05 | Ricoh Co Ltd | Ceramic dielectric film forming method, multilayered structure of ceramic dielectric film/substrate, and electro-mechanical transducer |
| JP4752156B2 (en) * | 2001-08-23 | 2011-08-17 | 株式会社村田製作所 | Piezoelectric ceramic composition for laminated piezoelectric element, laminated piezoelectric element, method for producing laminated piezoelectric element, and laminated piezoelectric device |
| JP4081809B2 (en) * | 2002-06-24 | 2008-04-30 | セイコーエプソン株式会社 | Method for manufacturing piezoelectric element |
| JP2004107181A (en) * | 2002-09-20 | 2004-04-08 | Canon Inc | Composition for forming piezoelectric element, method of manufacturing piezoelectric film, piezoelectric element and inkjet recording head |
| JP2004111835A (en) * | 2002-09-20 | 2004-04-08 | Canon Inc | Method of manufacturing piezoelectric element, piezoelectric element, and ink jet recording head |
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2006
- 2006-03-21 CN CNB2006100651402A patent/CN100505357C/en not_active Expired - Fee Related
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2008
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Non-Patent Citations (5)
| Title |
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| . . |
| Control of Leakage Resistance in Pb(Zr,Ti)O3 Thin Filmsby Donor Doping. Duane Dimos,Robert W. Schwartz,Steven J. Lockwood.JOURNAL OF THE AMERICAN CERAMIC SOCIETY,Vol.77 No.11. 1994 |
| Control of Leakage Resistance in Pb(Zr,Ti)O3 Thin Filmsby Donor Doping. Duane Dimos,Robert W. Schwartz,Steven J. Lockwood.JOURNAL OF THE AMERICAN CERAMIC SOCIETY,Vol.77 No.11. 1994 * |
| Lead zirconate titanate (PZT) film capacitor with amultilayerconstruction. Bang-Hung Tsao,Sandra Fries Carr,Joseph A. Weimer.Aerospace and Electronics Conference, 1998. NAECON 1998. Proceedings of the IEEE 1998 National. 1998 |
| Structural and Dielectric Properties of the PZTHeterolayered Films Prepared by Sol-Gel Technique. Sung-Gap Lee,In-Gil Park,Jang-Ho Chung,Young-Hie Lee.Proceedings of the 5th International Conference on Properties and Applications of Dielectric Materials. 1997 |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100479218C (en) | 2009-04-15 |
| CN1838444A (en) | 2006-09-27 |
| JP2009049433A (en) | 2009-03-05 |
| CN1838445A (en) | 2006-09-27 |
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