JPH1093158A - Piezoelectric material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric material exhibiting a high piezoelectric const., even in a film state. SOLUTION: A piezoelectric material is formed directly on a T or Zr metal film. It has a compsn. shown by x(Pb1-u M)ZrO3 -yPbTiO3 -zPb(B1,B2)O3 , where B1 is at least one element selected from among Mg, Zn, Ni, Cu, Mn, and Co; B2 is at least one element selected from among Ta, Nb and W; and M is an alkali earth metal selected from among Ba, Sr and Ca, 0<=x<=0.60, 0.05<=y<=0.90, 0<=z<=0.90, and 0<=u<=0.2 in mol ratios.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric material used for a vibrator or the like of an ink jet recording apparatus.

[0002]

2. Description of the Related Art Conventionally, zircon / lead titanate (PZT) has been known as a piezoelectric body. However, this PZ
When T is formed by sputtering or CVD, the piezoelectric properties are inferior to those of bulk. As a result, when the PZT film formed by sputtering or CVD was applied to a piezoelectric element of an ink jet recording apparatus, sufficient piezoelectric characteristics could not be obtained.

In an ink jet recording apparatus, an image is recorded by forming an image point by making liquid ink into small particles called droplets and flying on a recording medium.
It has been put to practical use as an inkjet printer. This ink-jet printer has the advantages that it has less noise than other recording methods and does not require processing such as development and fixing, and has thus attracted attention as a plain paper recording technique. At present, a number of ink jet printer systems have been invented, but a typical system is a system in which ink droplets are caused to fly by the pressure of steam generated by the heat of a heating element (for example, JP-B-56-9429 and JP-B-61). No. 59911) and a method of flying an ink droplet by a pressure pulse due to displacement of a piezoelectric body (for example, Japanese Patent Publication No. 53-12138). These ink jet printers fly ink from the tip of a nozzle. For this reason, local concentration of the ink occurs due to evaporation and volatilization of the solvent in the ink, and nozzle clogging occurs. Further, it is difficult for the conventional ink jet printer to reduce the particle size of the ink droplet to be ejected (for example, a diameter of 20 μm or less), so that it is difficult to increase the resolution.

[0004] In order to overcome such a problem, IB is used as a method of causing ink to fly from an ink liquid surface using the pressure (radiation pressure) of an ultrasonic beam generated by a piezoelectric element.
MTDB, Vol. No. 4, pp. 1168 (197
3-10), US Pat. No. 4,308,547 (198)
1), JP-A-63-313157, JP-A-2-184
No. 443 has been proposed. However, it has been difficult to efficiently fly ink because the piezoelectric material used in these methods has a small piezoelectric constant. as a result,
There is a problem that it is difficult to increase the image speed and that the flying efficiency is reduced when used for a long time.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a piezoelectric material having a high piezoelectric constant even in a film state.

[0006]

The piezoelectric material according to the present invention has a composition formula of x (Pb ₁ -uM) ZrO ₃ -yPbTiO ₃ -zPb.
(B1, B2) O ₃ (where B1 is Mg, Zn, Ni, Cu, Mn, Co
At least one element selected from the group consisting of Ta, N
b, at least one element selected from W, M is Ba,
An alkaline earth metal element selected from Sr and Ca, x,
y and z are respectively 0 ≦ x ≦ 0.60 and 0.05 in molar ratio.
≦ y ≦ 0.90, 0 ≦ z ≦ 0.90, u is 0 ≦
u ≦ 0.2) is represented by T or Z
r is formed directly on the metal film.

According to such a piezoelectric body according to the present invention, the specific piezoelectric material represented by the above-mentioned composition formula is made to be T or Z.
When formed directly on a metal film of r, the piezoelectric material exhibits a piezoelectric constant equivalent to that of bulk PZT, and thus can be applied to a piezoelectric element capable of emitting a high ultrasonic beam.

Further, a part of Pb is converted to M (Ba, Sr, C
The piezoelectric material substituted in the range of 20 mol% or less in T)
The piezoelectric characteristics can be further improved by directly forming them on the metal film of i and Zr.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a piezoelectric body according to the present invention will be described in detail. This piezoelectric body has a composition formula of x (Pb _{1-u
M) ZrO 3 -yPbTiO 3 -zPb (} B1, B2)
O ₃ (where B1 is Mg, Zn, Ni, Cu, Mn,
At least one element selected from Co, B2 is Ta,
At least one element selected from Nb and W;
an alkaline earth metal element selected from a, Sr, and Ca;
x, y, and z are 0 ≦ x ≦ 0.60, 0.
05 ≦ y ≦ 0.90, 0 ≦ z ≦ 0.90, u indicates a molar ratio of 0 ≦ u ≦ 0.2), and the piezoelectric material expressed directly was formed on a T or Zr metal film. Having a configuration. Here, xPbZrO ₃ -yPbTiO ₃ -zPb (B1,
B2) It is represented by O ₃ , and x, y, and z are each 0 in a molar ratio.
≦ x ≦ 0.60, 0.05 ≦ y ≦ 0.90, 0 ≦ z ≦
The composition range of 0.90 is shown in FIG.

The Pb (B1, B2) O ₃ includes, for example, Pb (Zn _1/3 Nb _2/3 ) O ₃ , Pb (Mg _1/3 N)
b _2/3 )] O ₃ , Pb (Ni _1/3 Nb _2/3 ) O ₃ , Pb
(Co _1/3 Nb _2/3 ) O ₃ , Pb (A _1/2 Nb _1/2 ) O
₃ can be mentioned.

In the piezoelectric material represented by the above composition formula,
If the values of x, y and z deviate from the above ranges, it becomes difficult to obtain a piezoelectric body having a high piezoelectric constant. In the piezoelectric material represented by the above composition formula, the mole number A of Pb, Ba, Sr, and Ca [Pb, Ba, Sr, Ca] and the mole number of other elements B [Mg, Zn, Ni, Cu, Mn] , Co, Ta,
Nb, W] is preferably 0.95 ≦ A / B ≦ 0.99. By setting A / B within the above range, it is possible to suppress the deterioration of the piezoelectric characteristics due to the repetition of the piezoelectric vibration.

It is preferable that the thickness of the piezoelectric material is 5 to 200 μm. When the thickness of the piezoelectric material is less than 5 μm, it becomes difficult to obtain a piezoelectric body having a sufficiently high piezoelectric constant. On the other hand, the thickness of the piezoelectric material is 200 μm.
If it exceeds m, the film composition may be non-uniform and the characteristics may vary. On the other hand, the image accuracy changes according to the ink particle size, and the ink particle size is determined by the frequency of the ultrasonic wave generated from the piezoelectric body. Therefore, in order to obtain an appropriate ink particle diameter, it is necessary to set the frequency of the ultrasonic wave generated from the piezoelectric body to an appropriate value. Ultrasonic waves generated from the piezoelectric body change depending on the thickness of the piezoelectric body. For these reasons, the thickness of the piezoelectric body required to generate ink droplets of an appropriate size is determined, and although the thickness slightly varies depending on the type of piezoelectric body, the thickness of the piezoelectric body is generally set within a range of 10 to 100 μm. It is desirable to do.

The piezoelectric material may be formed by, for example, sputtering, CV
It is formed on the metal film by the D method or the coating method. In order to manufacture a piezoelectric element from the piezoelectric body, a method is employed in which a piezoelectric material coated with the metal is cut into desired dimensions, and electrodes are formed on the surface of the metal film and the surface on the opposite side. As the electrode, for example, an Au electrode,
A Cr electrode or the like can be used. These electrodes are formed by a sputtering method, a vapor deposition method, a coating method, or the like.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail. Example 1 First, an Au electrode having a thickness of 0.2 μm was formed on a glass substrate by sputtering, and a Ti film having a thickness of 10 μm was formed on the Au electrode. Subsequently, 1N Pb (NO _{3) 3} solution, 1N ZrOCl ₂ · 8
H ₂ O solution, 2.5 TiCl ₄ aqueous solution of defined, 1N _{Mg (NO 3) 2 · 6H} 2 O solution and 1 N N
with Bcl ₅ aqueous Pb [Zr _0.45 Ti _0.40 (Mg
_1/3 Nb _{2/3) 0.15)} was prepared to have the composition of O _3,
This mixed solution was put into a reaction vessel autoclave together with the glass substrate on which the Ti film was formed. By treating this reaction container at 150 ° C. for 72 hours, a 50 μm thick Pb [Zr _0.45 Ti _0.40 (M
g _1/3 Nb _2/3 ) _0.15 ) O ₃ film was formed. Subsequently, a thickness of 0.2 μm was formed on the piezoelectric material film by sputtering.
Was formed to produce a piezoelectric element.

Comparative Example 1 A piezoelectric element was manufactured in the same manner as in Example 1 except that a piezoelectric material was formed directly on a glass substrate without forming an Au electrode.

Comparative Example 2 PbO, ZrO ₂ , and TiO were used as starting materials so as to have the same composition as the piezoelectric body of Example 1.
₂ , MgCO ₃ , Nb ₂ O _{5 is made} into a paste, which is formed on a glass substrate by sputtering to a thickness of 0.2 μm.
A piezoelectric element was fabricated by applying the film on a Au electrode having a thickness of 1 m and heating at 1200 ° C. for 2 hours to form a piezoelectric body having a thickness of 1 mm.

Regarding the obtained piezoelectric elements of Example 1 and Comparative Examples 1 and 2, 1.5 ° C. was applied between a pair of Au electrodes at 100 ° C.
After applying a voltage of kV and polarizing, the piezoelectric constant (Kt) was measured. As a result, the piezoelectric elements of Example 1 and Comparative Examples 1 and 2 had Kt of 43%, 35% and 30%, respectively. In Comparative Examples 1 and 2, although a phenomenon occurs in which the piezoelectric properties are reduced when the piezoelectric body is formed into a thin film, the piezoelectric properties are reduced when the piezoelectric body is formed via Ti as in the present invention. It can be seen that a thin film-shaped piezoelectric element can be obtained without using the same.

Example 2 First, an Au electrode having a thickness of 0.2 μm was formed on a glass substrate by sputtering, and a Ti film having a thickness of 10 μm was formed on the Au electrode. Subsequently, 1N Pb (NO ₃ ) ₃ aqueous solution, 1N Ba
Cl ₂ solution, 1N ZrOCl ₂ · 8H ₂ O aqueous solution, 2.5 TiCl ₄ aqueous solution of defined, 1N ZnCl
_{Using 2} aqueous solution and 1N aqueous NbCl ₅ solution (P
b _0.95 Ba _0.05 ) [Zr _0.50 Ti _0.40 (Zn _1/3 Nb
_2/3 ) _0.10 ] O ₃ was prepared and the mixed solution was placed in a reaction vessel autoclave together with the glass substrate on which the Ti film was formed. 150 ° C
For 72 hours on the Ti film, a (Pb _0.95 Ba _0.05 ) [Zr _0.50 Ti
_0.40 (Zn _1/3 Nb _2/3 ) _0.10 ] O ₃ film was formed. Subsequently, the thickness of the piezoelectric material film was reduced to 0.
A 2 μm Au electrode was formed to produce a piezoelectric element.

Regarding the obtained piezoelectric element of Example 2, 1
After a voltage of 1.5 kV was applied between the pair of Au electrodes at 00 ° C. for polarization, the piezoelectric constant (Kt) was measured. As a result, it was confirmed that Kt exhibited a high piezoelectric constant of 45%.

(Embodiment 3) FIG. 2 is a perspective view showing an ink jet printer manufactured in Embodiment 3 of the present invention.

First, an Au film having a thickness of 0.2 μm was formed on a glass substrate 1 as a backing material by sputtering, and then the Au film was patterned by selective etching to form an Au individual electrode 2. This Au individual electrode was made to have a width of one element of 60 μm and an electrode interval of 25 μm.
Subsequently, after filling the space between the individual electrodes with an insulating material made of epoxy resin so as to be flush with the individual electrode surface, a 10 μm-thick Ti film (not shown) is formed by sputtering. Pb [Zr _0.45 Ti _0.40 (Mg _1/3 Nb)
_2/3 ) _0.15 ) O ₃ film 3 was formed. Note that a piezoelectric body was constituted by the Ti film and the piezoelectric material film. The glass substrate 1 has a sound speed of 6000 m / s and a thickness of 1.2 μm.
m. Accordingly, at a driving frequency of 50 MHz, since the wavelength is 120 μm, the thickness is は, which is 20 times larger than the thickness.

Next, an Al common electrode 4 was formed on the piezoelectric material film by sputtering. At this time, the electrode length in the sub-scanning direction, that is, the aperture was 1.5 mm. Then, the sound velocity of the alumina powder and the epoxy resin was 3 × 1103 m /
The mixture ratio is adjusted so as to be in the vicinity of s, the mixture is applied on the common electrode 4 and cured to a thickness of about 45 μm, a density of 2.20 × 103 kg / m ³ , and a sound speed of 2.95 × 103.
An m / s layer was formed. Subsequently, the surface of this layer was polished, and grooves having a half wavelength (approximately 30 μm) in depth were cut so as to have a focal length of 3.5 mm so as to be parallel to each other in the main scanning direction. Formed. Further, the distance between the ultrasonic radiation surface and the liquid surface of the ink 6 is approximately 3.
Side walls 7a and 7b were formed so as to be 5 mm, and a driving circuit 8 connected to the individual electrodes 2 was attached to the non-electrode surface of the glass substrate 1 to manufacture an ink jet recording apparatus.

Comparative Example 3 An ink jet recording apparatus similar to that of Example 3 was manufactured using a Pb (Zr _0.53 Ti _0.47 ) O ₃ film having a thickness of 50 μm as a piezoelectric substance.

Flying experiments were performed on the obtained ink jet recording apparatuses of Example 3 and Comparative Example 3. First,
Among the conditions under which a 100% ink droplet flies by drawing a straight line in the main scanning direction using the ink jet recording apparatus of Example 3, numerical values with a low drive voltage and a small burst wave number were obtained. When a flight experiment was performed on the recording apparatus of Comparative Example 3 under these conditions, the flying ratio was about 70%. From this result, it can be seen that the recording device of Example 3 has improved flying efficiency as compared with the recording device of Comparative Example 3.

Further, 100% ink droplets were made to fly by changing the burst wave number using the recording apparatus of Comparative Example 3. As a result, the number of burst waves increases, and the repetition period also needs to be increased. Comparing the recording speeds of the recording apparatuses of Comparative Example 3 and Example 3, the same contents can be printed in Example 3 in about 65% of the time of Comparative Example 3, and the recording speed is increased. I was able to.

[0026]

As described above, the piezoelectric material according to the present invention has a composition formula of x (Pb ₁ -uM) ZrO ₃ -yPbTi.
O ₃ -zPb (B1, B2) O ₃ (where B1 is M
g, at least one element selected from Zn, Ni, Cu, Mn, Co, B2 is at least one element selected from Ta, Nb, W, M is an alkaline earth metal selected from Ba, Sr, Ca The elements, x, y, and z, are each in molar ratio of 0 ≦ x ≦ 0.60, 0.05 ≦ y ≦ 0.90, 0 ≦ z
.Ltoreq.0.90, u represents a molar ratio of 0.ltoreq.u.ltoreq.0.2), and has a structure in which a piezoelectric material directly formed on a T or Zr metal film has a high piezoelectric constant in a film state. Therefore, a remarkable effect such as effective use for a piezoelectric element or the like of an ink jet recording apparatus is exhibited.

[Brief description of the drawings]

FIG. 1 shows xPbZrO ₃ -yP of a piezoelectric material according to the present invention.
A craft showing the composition range of bTiO ₃ -zPb (B1, B2) O ₃ .

FIG. 2 is a perspective view illustrating an inkjet recording apparatus according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Glass substrate (backing material), 2 ... Individual electrode, 3 ... Piezoelectric material layer, 4 ... Common electrode 5 ... Fresnel lens, 6 ... Ink.

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI H01L 41/22

Claims (1)

[Claims] 1. The composition formula is x (Pb ₁ -uM) ZrO ₃ -yPbTiO ₃ -zPb
(B1, B2) O ₃ (where B1 is Mg, Zn, Ni, Cu, Mn, Co
At least one element selected from the group consisting of Ta, N
b, at least one element selected from W, M is Ba,
An alkaline earth metal element selected from Sr and Ca, x,
y and z are respectively 0 ≦ x ≦ 0.60 and 0.05 in molar ratio.
≦ y ≦ 0.90, 0 ≦ z ≦ 0.90, u is 0 ≦
a piezoelectric material represented by u ≦ 0.2) is formed directly on a metal film of Ti or Zr.